Fix: add missing rcu_barrier at end of sessiond main
[lttng-tools.git] / src / bin / lttng-sessiond / main.c
index d999928feb8a0f06bfe24857fc3182f56c4f903f..43f750a820fbf7c087ca9e5df4d275b3cc065cc9 100644 (file)
@@ -1,6 +1,7 @@
 /*
  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *               2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License, version 2 only,
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <getopt.h>
 #include <grp.h>
 #include <limits.h>
+#include <paths.h>
 #include <pthread.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <inttypes.h>
 #include <sys/mman.h>
 #include <sys/mount.h>
 #include <sys/resource.h>
 #include <config.h>
 
 #include <common/common.h>
-#include <common/compat/poll.h>
 #include <common/compat/socket.h>
+#include <common/compat/getenv.h>
 #include <common/defaults.h>
 #include <common/kernel-consumer/kernel-consumer.h>
 #include <common/futex.h>
 #include <common/relayd/relayd.h>
 #include <common/utils.h>
+#include <common/daemonize.h>
+#include <common/config/config.h>
 
 #include "lttng-sessiond.h"
+#include "buffer-registry.h"
 #include "channel.h"
 #include "cmd.h"
 #include "consumer.h"
 #include "ust-consumer.h"
 #include "utils.h"
 #include "fd-limit.h"
-#include "health.h"
+#include "health-sessiond.h"
 #include "testpoint.h"
+#include "ust-thread.h"
+#include "agent-thread.h"
+#include "save.h"
+#include "load-session-thread.h"
+#include "syscall.h"
+#include "agent.h"
 
 #define CONSUMERD_FILE "lttng-consumerd"
 
-/* Const values */
-const char default_home_dir[] = DEFAULT_HOME_DIR;
-const char default_tracing_group[] = DEFAULT_TRACING_GROUP;
-const char default_ust_sock_dir[] = DEFAULT_UST_SOCK_DIR;
-const char default_global_apps_pipe[] = DEFAULT_GLOBAL_APPS_PIPE;
-
 const char *progname;
-const char *opt_tracing_group;
-static const char *opt_pidfile;
+static const char *tracing_group_name = DEFAULT_TRACING_GROUP;
+static int tracing_group_name_override;
+static char *opt_pidfile;
 static int opt_sig_parent;
 static int opt_verbose_consumer;
-static int opt_daemon;
+static int opt_daemon, opt_background;
 static int opt_no_kernel;
-static int is_root;                    /* Set to 1 if the daemon is running as root */
+static char *opt_load_session_path;
 static pid_t ppid;          /* Parent PID for --sig-parent option */
+static pid_t child_ppid;    /* Internal parent PID use with daemonize. */
 static char *rundir;
+static int lockfile_fd = -1;
+
+/* Set to 1 when a SIGUSR1 signal is received. */
+static int recv_child_signal;
 
 /*
  * Consumer daemon specific control data. Every value not initialized here is
@@ -119,6 +132,42 @@ static struct consumer_data ustconsumer32_data = {
        .cond_mutex = PTHREAD_MUTEX_INITIALIZER,
 };
 
+/* Command line options */
+static const struct option long_options[] = {
+       { "client-sock", required_argument, 0, 'c' },
+       { "apps-sock", required_argument, 0, 'a' },
+       { "kconsumerd-cmd-sock", required_argument, 0, '\0' },
+       { "kconsumerd-err-sock", required_argument, 0, '\0' },
+       { "ustconsumerd32-cmd-sock", required_argument, 0, '\0' },
+       { "ustconsumerd32-err-sock", required_argument, 0, '\0' },
+       { "ustconsumerd64-cmd-sock", required_argument, 0, '\0' },
+       { "ustconsumerd64-err-sock", required_argument, 0, '\0' },
+       { "consumerd32-path", required_argument, 0, '\0' },
+       { "consumerd32-libdir", required_argument, 0, '\0' },
+       { "consumerd64-path", required_argument, 0, '\0' },
+       { "consumerd64-libdir", required_argument, 0, '\0' },
+       { "daemonize", no_argument, 0, 'd' },
+       { "background", no_argument, 0, 'b' },
+       { "sig-parent", no_argument, 0, 'S' },
+       { "help", no_argument, 0, 'h' },
+       { "group", required_argument, 0, 'g' },
+       { "version", no_argument, 0, 'V' },
+       { "quiet", no_argument, 0, 'q' },
+       { "verbose", no_argument, 0, 'v' },
+       { "verbose-consumer", no_argument, 0, '\0' },
+       { "no-kernel", no_argument, 0, '\0' },
+       { "pidfile", required_argument, 0, 'p' },
+       { "agent-tcp-port", required_argument, 0, '\0' },
+       { "config", required_argument, 0, 'f' },
+       { "load", required_argument, 0, 'l' },
+       { "kmod-probes", required_argument, 0, '\0' },
+       { "extra-kmod-probes", required_argument, 0, '\0' },
+       { NULL, 0, 0, 0 }
+};
+
+/* Command line options to ignore from configuration file */
+static const char *config_ignore_options[] = { "help", "version", "config" };
+
 /* Shared between threads */
 static int dispatch_thread_exit;
 
@@ -142,6 +191,7 @@ static int kernel_poll_pipe[2] = { -1, -1 };
  * for all threads when receiving an event on the pipe.
  */
 static int thread_quit_pipe[2] = { -1, -1 };
+static int ht_cleanup_quit_pipe[2] = { -1, -1 };
 
 /*
  * This pipe is used to inform the thread managing application communication
@@ -149,20 +199,28 @@ static int thread_quit_pipe[2] = { -1, -1 };
  */
 static int apps_cmd_pipe[2] = { -1, -1 };
 
+int apps_cmd_notify_pipe[2] = { -1, -1 };
+
 /* Pthread, Mutexes and Semaphores */
 static pthread_t apps_thread;
+static pthread_t apps_notify_thread;
 static pthread_t reg_apps_thread;
 static pthread_t client_thread;
 static pthread_t kernel_thread;
 static pthread_t dispatch_thread;
 static pthread_t health_thread;
+static pthread_t ht_cleanup_thread;
+static pthread_t agent_reg_thread;
+static pthread_t load_session_thread;
 
 /*
  * UST registration command queue. This queue is tied with a futex and uses a N
  * wakers / 1 waiter implemented and detailed in futex.c/.h
  *
- * The thread_manage_apps and thread_dispatch_ust_registration interact with
- * this queue and the wait/wake scheme.
+ * The thread_registration_apps and thread_dispatch_ust_registration uses this
+ * queue along with the wait/wake scheme. The thread_manage_apps receives down
+ * the line new application socket and monitors it for any I/O error or clean
+ * close that triggers an unregistration of the application.
  */
 static struct ust_cmd_queue ust_cmd_queue;
 
@@ -185,6 +243,10 @@ static const char *consumerd32_bin = CONFIG_CONSUMERD32_BIN;
 static const char *consumerd64_bin = CONFIG_CONSUMERD64_BIN;
 static const char *consumerd32_libdir = CONFIG_CONSUMERD32_LIBDIR;
 static const char *consumerd64_libdir = CONFIG_CONSUMERD64_LIBDIR;
+static int consumerd32_bin_override;
+static int consumerd64_bin_override;
+static int consumerd32_libdir_override;
+static int consumerd64_libdir_override;
 
 static const char *module_proc_lttng = "/proc/lttng";
 
@@ -222,17 +284,63 @@ enum consumerd_state {
 static enum consumerd_state ust_consumerd_state;
 static enum consumerd_state kernel_consumerd_state;
 
-/* Used for the health monitoring of the session daemon. See health.h */
-struct health_state health_thread_cmd;
-struct health_state health_thread_app_manage;
-struct health_state health_thread_app_reg;
-struct health_state health_thread_kernel;
-
 /*
  * Socket timeout for receiving and sending in seconds.
  */
 static int app_socket_timeout;
 
+/* Set in main() with the current page size. */
+long page_size;
+
+/* Application health monitoring */
+struct health_app *health_sessiond;
+
+/* Agent TCP port for registration. Used by the agent thread. */
+unsigned int agent_tcp_port = DEFAULT_AGENT_TCP_PORT;
+
+/* Am I root or not. */
+int is_root;                   /* Set to 1 if the daemon is running as root */
+
+const char * const config_section_name = "sessiond";
+
+/* Load session thread information to operate. */
+struct load_session_thread_data *load_info;
+
+/* Global hash tables */
+struct lttng_ht *agent_apps_ht_by_sock = NULL;
+
+/*
+ * Whether sessiond is ready for commands/health check requests.
+ * NR_LTTNG_SESSIOND_READY must match the number of calls to
+ * sessiond_notify_ready().
+ */
+#define NR_LTTNG_SESSIOND_READY                3
+int lttng_sessiond_ready = NR_LTTNG_SESSIOND_READY;
+
+/* Notify parents that we are ready for cmd and health check */
+LTTNG_HIDDEN
+void sessiond_notify_ready(void)
+{
+       if (uatomic_sub_return(&lttng_sessiond_ready, 1) == 0) {
+               /*
+                * Notify parent pid that we are ready to accept command
+                * for client side.  This ppid is the one from the
+                * external process that spawned us.
+                */
+               if (opt_sig_parent) {
+                       kill(ppid, SIGUSR1);
+               }
+
+               /*
+                * Notify the parent of the fork() process that we are
+                * ready.
+                */
+               if (opt_daemon || opt_background) {
+                       kill(child_ppid, SIGUSR1);
+               }
+       }
+}
+
 static
 void setup_consumerd_path(void)
 {
@@ -264,36 +372,31 @@ void setup_consumerd_path(void)
        /*
         * runtime env. var. overrides the build default.
         */
-       bin = getenv("LTTNG_CONSUMERD32_BIN");
+       bin = lttng_secure_getenv("LTTNG_CONSUMERD32_BIN");
        if (bin) {
                consumerd32_bin = bin;
        }
-       bin = getenv("LTTNG_CONSUMERD64_BIN");
+       bin = lttng_secure_getenv("LTTNG_CONSUMERD64_BIN");
        if (bin) {
                consumerd64_bin = bin;
        }
-       libdir = getenv("LTTNG_CONSUMERD32_LIBDIR");
+       libdir = lttng_secure_getenv("LTTNG_CONSUMERD32_LIBDIR");
        if (libdir) {
                consumerd32_libdir = libdir;
        }
-       libdir = getenv("LTTNG_CONSUMERD64_LIBDIR");
+       libdir = lttng_secure_getenv("LTTNG_CONSUMERD64_LIBDIR");
        if (libdir) {
                consumerd64_libdir = libdir;
        }
 }
 
-/*
- * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
- */
-static int create_thread_poll_set(struct lttng_poll_event *events,
-               unsigned int size)
+static
+int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
+               int *a_pipe)
 {
        int ret;
 
-       if (events == NULL || size == 0) {
-               ret = -1;
-               goto error;
-       }
+       assert(events);
 
        ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
        if (ret < 0) {
@@ -301,7 +404,7 @@ static int create_thread_poll_set(struct lttng_poll_event *events,
        }
 
        /* Add quit pipe */
-       ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN);
+       ret = lttng_poll_add(events, a_pipe[0], LPOLLIN | LPOLLERR);
        if (ret < 0) {
                goto error;
        }
@@ -313,36 +416,52 @@ error:
 }
 
 /*
- * Check if the thread quit pipe was triggered.
- *
- * Return 1 if it was triggered else 0;
+ * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
+ */
+int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size)
+{
+       return __sessiond_set_thread_pollset(events, size, thread_quit_pipe);
+}
+
+/*
+ * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
  */
-static int check_thread_quit_pipe(int fd, uint32_t events)
+int sessiond_set_ht_cleanup_thread_pollset(struct lttng_poll_event *events,
+               size_t size)
+{
+       return __sessiond_set_thread_pollset(events, size,
+                       ht_cleanup_quit_pipe);
+}
+
+static
+int __sessiond_check_thread_quit_pipe(int fd, uint32_t events, int a_pipe)
 {
-       if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
+       if (fd == a_pipe && (events & LPOLLIN)) {
                return 1;
        }
-
        return 0;
 }
 
 /*
- * Return group ID of the tracing group or -1 if not found.
+ * Check if the thread quit pipe was triggered.
+ *
+ * Return 1 if it was triggered else 0;
  */
-static gid_t allowed_group(void)
+int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
 {
-       struct group *grp;
+       return __sessiond_check_thread_quit_pipe(fd, events,
+                       thread_quit_pipe[0]);
+}
 
-       if (opt_tracing_group) {
-               grp = getgrnam(opt_tracing_group);
-       } else {
-               grp = getgrnam(default_tracing_group);
-       }
-       if (!grp) {
-               return -1;
-       } else {
-               return grp->gr_gid;
-       }
+/*
+ * Check if the ht_cleanup thread quit pipe was triggered.
+ *
+ * Return 1 if it was triggered else 0;
+ */
+int sessiond_check_ht_cleanup_quit(int fd, uint32_t events)
+{
+       return __sessiond_check_thread_quit_pipe(fd, events,
+                       ht_cleanup_quit_pipe[0]);
 }
 
 /*
@@ -350,18 +469,18 @@ static gid_t allowed_group(void)
  *
  * Return -1 on error or 0 if all pipes are created.
  */
-static int init_thread_quit_pipe(void)
+static int __init_thread_quit_pipe(int *a_pipe)
 {
        int ret, i;
 
-       ret = pipe(thread_quit_pipe);
+       ret = pipe(a_pipe);
        if (ret < 0) {
                PERROR("thread quit pipe");
                goto error;
        }
 
        for (i = 0; i < 2; i++) {
-               ret = fcntl(thread_quit_pipe[i], F_SETFD, FD_CLOEXEC);
+               ret = fcntl(a_pipe[i], F_SETFD, FD_CLOEXEC);
                if (ret < 0) {
                        PERROR("fcntl");
                        goto error;
@@ -372,6 +491,16 @@ error:
        return ret;
 }
 
+static int init_thread_quit_pipe(void)
+{
+       return __init_thread_quit_pipe(thread_quit_pipe);
+}
+
+static int init_ht_cleanup_quit_pipe(void)
+{
+       return __init_thread_quit_pipe(ht_cleanup_quit_pipe);
+}
+
 /*
  * Stop all threads by closing the thread quit pipe.
  */
@@ -392,17 +521,86 @@ static void stop_threads(void)
 }
 
 /*
- * Cleanup the daemon
+ * Close every consumer sockets.
+ */
+static void close_consumer_sockets(void)
+{
+       int ret;
+
+       if (kconsumer_data.err_sock >= 0) {
+               ret = close(kconsumer_data.err_sock);
+               if (ret < 0) {
+                       PERROR("kernel consumer err_sock close");
+               }
+       }
+       if (ustconsumer32_data.err_sock >= 0) {
+               ret = close(ustconsumer32_data.err_sock);
+               if (ret < 0) {
+                       PERROR("UST consumerd32 err_sock close");
+               }
+       }
+       if (ustconsumer64_data.err_sock >= 0) {
+               ret = close(ustconsumer64_data.err_sock);
+               if (ret < 0) {
+                       PERROR("UST consumerd64 err_sock close");
+               }
+       }
+       if (kconsumer_data.cmd_sock >= 0) {
+               ret = close(kconsumer_data.cmd_sock);
+               if (ret < 0) {
+                       PERROR("kernel consumer cmd_sock close");
+               }
+       }
+       if (ustconsumer32_data.cmd_sock >= 0) {
+               ret = close(ustconsumer32_data.cmd_sock);
+               if (ret < 0) {
+                       PERROR("UST consumerd32 cmd_sock close");
+               }
+       }
+       if (ustconsumer64_data.cmd_sock >= 0) {
+               ret = close(ustconsumer64_data.cmd_sock);
+               if (ret < 0) {
+                       PERROR("UST consumerd64 cmd_sock close");
+               }
+       }
+}
+
+/*
+ * Generate the full lock file path using the rundir.
+ *
+ * Return the snprintf() return value thus a negative value is an error.
+ */
+static int generate_lock_file_path(char *path, size_t len)
+{
+       int ret;
+
+       assert(path);
+       assert(rundir);
+
+       /* Build lockfile path from rundir. */
+       ret = snprintf(path, len, "%s/" DEFAULT_LTTNG_SESSIOND_LOCKFILE, rundir);
+       if (ret < 0) {
+               PERROR("snprintf lockfile path");
+       }
+
+       return ret;
+}
+
+/*
+ * Cleanup the session daemon's data structures.
  */
-static void cleanup(void)
+static void sessiond_cleanup(void)
 {
        int ret;
-       char *cmd = NULL;
        struct ltt_session *sess, *stmp;
+       char path[PATH_MAX];
 
-       DBG("Cleaning up");
+       DBG("Cleanup sessiond");
 
-       /* First thing first, stop all threads */
+       /*
+        * Close the thread quit pipe. It has already done its job,
+        * since we are now called.
+        */
        utils_close_pipe(thread_quit_pipe);
 
        /*
@@ -416,19 +614,58 @@ static void cleanup(void)
                }
        }
 
-       DBG("Removing %s directory", rundir);
-       ret = asprintf(&cmd, "rm -rf %s", rundir);
-       if (ret < 0) {
-               ERR("asprintf failed. Something is really wrong!");
-       }
-
-       /* Remove lttng run directory */
-       ret = system(cmd);
-       if (ret < 0) {
-               ERR("Unable to clean %s", rundir);
-       }
-       free(cmd);
-       free(rundir);
+       DBG("Removing sessiond and consumerd content of directory %s", rundir);
+
+       /* sessiond */
+       snprintf(path, PATH_MAX,
+               "%s/%s",
+               rundir, DEFAULT_LTTNG_SESSIOND_PIDFILE);
+       DBG("Removing %s", path);
+       (void) unlink(path);
+
+       snprintf(path, PATH_MAX, "%s/%s", rundir,
+                       DEFAULT_LTTNG_SESSIOND_AGENTPORT_FILE);
+       DBG("Removing %s", path);
+       (void) unlink(path);
+
+       /* kconsumerd */
+       snprintf(path, PATH_MAX,
+               DEFAULT_KCONSUMERD_ERR_SOCK_PATH,
+               rundir);
+       DBG("Removing %s", path);
+       (void) unlink(path);
+
+       snprintf(path, PATH_MAX,
+               DEFAULT_KCONSUMERD_PATH,
+               rundir);
+       DBG("Removing directory %s", path);
+       (void) rmdir(path);
+
+       /* ust consumerd 32 */
+       snprintf(path, PATH_MAX,
+               DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH,
+               rundir);
+       DBG("Removing %s", path);
+       (void) unlink(path);
+
+       snprintf(path, PATH_MAX,
+               DEFAULT_USTCONSUMERD32_PATH,
+               rundir);
+       DBG("Removing directory %s", path);
+       (void) rmdir(path);
+
+       /* ust consumerd 64 */
+       snprintf(path, PATH_MAX,
+               DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH,
+               rundir);
+       DBG("Removing %s", path);
+       (void) unlink(path);
+
+       snprintf(path, PATH_MAX,
+               DEFAULT_USTCONSUMERD64_PATH,
+               rundir);
+       DBG("Removing directory %s", path);
+       (void) rmdir(path);
 
        DBG("Cleaning up all sessions");
 
@@ -443,8 +680,12 @@ static void cleanup(void)
                }
        }
 
+       DBG("Cleaning up all agent apps");
+       agent_app_ht_clean();
+
        DBG("Closing all UST sockets");
        ust_app_clean_list();
+       buffer_reg_destroy_registries();
 
        if (is_root && !opt_no_kernel) {
                DBG2("Closing kernel fd");
@@ -456,8 +697,78 @@ static void cleanup(void)
                }
                DBG("Unloading kernel modules");
                modprobe_remove_lttng_all();
+               free(syscall_table);
+       }
+
+       close_consumer_sockets();
+
+       if (load_info) {
+               load_session_destroy_data(load_info);
+               free(load_info);
+       }
+
+       /*
+        * Cleanup lock file by deleting it and finaly closing it which will
+        * release the file system lock.
+        */
+       if (lockfile_fd >= 0) {
+               char lockfile_path[PATH_MAX];
+
+               ret = generate_lock_file_path(lockfile_path,
+                               sizeof(lockfile_path));
+               if (ret > 0) {
+                       ret = remove(lockfile_path);
+                       if (ret < 0) {
+                               PERROR("remove lock file");
+                       }
+                       ret = close(lockfile_fd);
+                       if (ret < 0) {
+                               PERROR("close lock file");
+                       }
+               }
+       }
+
+       /*
+        * We do NOT rmdir rundir because there are other processes
+        * using it, for instance lttng-relayd, which can start in
+        * parallel with this teardown.
+        */
+
+       free(rundir);
+}
+
+/*
+ * Cleanup the daemon's option data structures.
+ */
+static void sessiond_cleanup_options(void)
+{
+       DBG("Cleaning up options");
+
+       /*
+        * If the override option is set, the pointer points to a *non* const
+        * thus freeing it even though the variable type is set to const.
+        */
+       if (tracing_group_name_override) {
+               free((void *) tracing_group_name);
+       }
+       if (consumerd32_bin_override) {
+               free((void *) consumerd32_bin);
+       }
+       if (consumerd64_bin_override) {
+               free((void *) consumerd64_bin);
+       }
+       if (consumerd32_libdir_override) {
+               free((void *) consumerd32_libdir);
+       }
+       if (consumerd64_libdir_override) {
+               free((void *) consumerd64_libdir);
        }
 
+       free(opt_pidfile);
+       free(opt_load_session_path);
+       free(kmod_probes_list);
+       free(kmod_extra_probes_list);
+
        /* <fun> */
        DBG("%c[%d;%dm*** assert failed :-) *** ==> %c[%dm%c[%d;%dm"
                        "Matthew, BEET driven development works!%c[%dm",
@@ -621,42 +932,47 @@ static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
                }
                ksess = session->kernel_session;
 
-               cds_list_for_each_entry(channel, &ksess->channel_list.head, list) {
-                       if (channel->fd == fd) {
-                               DBG("Channel found, updating kernel streams");
-                               ret = kernel_open_channel_stream(channel);
-                               if (ret < 0) {
-                                       goto error;
-                               }
+               cds_list_for_each_entry(channel,
+                               &ksess->channel_list.head, list) {
+                       struct lttng_ht_iter iter;
+                       struct consumer_socket *socket;
 
-                               /*
-                                * Have we already sent fds to the consumer? If yes, it means
-                                * that tracing is started so it is safe to send our updated
-                                * stream fds.
-                                */
-                               if (ksess->consumer_fds_sent == 1 && ksess->consumer != NULL) {
-                                       struct lttng_ht_iter iter;
-                                       struct consumer_socket *socket;
-
-                                       rcu_read_lock();
-                                       cds_lfht_for_each_entry(ksess->consumer->socks->ht,
-                                                       &iter.iter, socket, node.node) {
-                                               /* Code flow error */
-                                               assert(socket->fd >= 0);
-
-                                               pthread_mutex_lock(socket->lock);
-                                               ret = kernel_consumer_send_channel_stream(socket,
-                                                               channel, ksess);
-                                               pthread_mutex_unlock(socket->lock);
-                                               if (ret < 0) {
-                                                       rcu_read_unlock();
-                                                       goto error;
-                                               }
-                                       }
+                       if (channel->fd != fd) {
+                               continue;
+                       }
+                       DBG("Channel found, updating kernel streams");
+                       ret = kernel_open_channel_stream(channel);
+                       if (ret < 0) {
+                               goto error;
+                       }
+                       /* Update the stream global counter */
+                       ksess->stream_count_global += ret;
+
+                       /*
+                        * Have we already sent fds to the consumer? If yes, it
+                        * means that tracing is started so it is safe to send
+                        * our updated stream fds.
+                        */
+                       if (ksess->consumer_fds_sent != 1
+                                       || ksess->consumer == NULL) {
+                               ret = -1;
+                               goto error;
+                       }
+
+                       rcu_read_lock();
+                       cds_lfht_for_each_entry(ksess->consumer->socks->ht,
+                                       &iter.iter, socket, node.node) {
+                               pthread_mutex_lock(socket->lock);
+                               ret = kernel_consumer_send_channel_stream(socket,
+                                               channel, ksess,
+                                               session->output_traces ? 1 : 0);
+                               pthread_mutex_unlock(socket->lock);
+                               if (ret < 0) {
                                        rcu_read_unlock();
+                                       goto error;
                                }
-                               goto error;
                        }
+                       rcu_read_unlock();
                }
                session_unlock(session);
        }
@@ -670,24 +986,47 @@ error:
 }
 
 /*
- * For each tracing session, update newly registered apps.
+ * For each tracing session, update newly registered apps. The session list
+ * lock MUST be acquired before calling this.
  */
 static void update_ust_app(int app_sock)
 {
        struct ltt_session *sess, *stmp;
 
-       session_lock_list();
+       /* Consumer is in an ERROR state. Stop any application update. */
+       if (uatomic_read(&ust_consumerd_state) == CONSUMER_ERROR) {
+               /* Stop the update process since the consumer is dead. */
+               return;
+       }
 
        /* For all tracing session(s) */
        cds_list_for_each_entry_safe(sess, stmp, &session_list_ptr->head, list) {
+               struct ust_app *app;
+
                session_lock(sess);
-               if (sess->ust_session) {
-                       ust_app_global_update(sess->ust_session, app_sock);
+               if (!sess->ust_session) {
+                       goto unlock_session;
+               }
+
+               rcu_read_lock();
+               assert(app_sock >= 0);
+               app = ust_app_find_by_sock(app_sock);
+               if (app == NULL) {
+                       /*
+                        * Application can be unregistered before so
+                        * this is possible hence simply stopping the
+                        * update.
+                        */
+                       DBG3("UST app update failed to find app sock %d",
+                               app_sock);
+                       goto unlock_rcu;
                }
+               ust_app_global_update(sess->ust_session, app);
+       unlock_rcu:
+               rcu_read_unlock();
+       unlock_session:
                session_unlock(sess);
        }
-
-       session_unlock_list();
 }
 
 /*
@@ -705,32 +1044,32 @@ static void *thread_manage_kernel(void *data)
 
        DBG("[thread] Thread manage kernel started");
 
-       health_register(HEALTH_TYPE_KERNEL);
+       health_register(health_sessiond, HEALTH_SESSIOND_TYPE_KERNEL);
 
        /*
         * This first step of the while is to clean this structure which could free
-        * non NULL pointers so zero it before the loop.
+        * non NULL pointers so initialize it before the loop.
         */
-       memset(&events, 0, sizeof(events));
+       lttng_poll_init(&events);
 
-       if (testpoint(thread_manage_kernel)) {
+       if (testpoint(sessiond_thread_manage_kernel)) {
                goto error_testpoint;
        }
 
-       health_code_update(&health_thread_kernel);
+       health_code_update();
 
-       if (testpoint(thread_manage_kernel_before_loop)) {
+       if (testpoint(sessiond_thread_manage_kernel_before_loop)) {
                goto error_testpoint;
        }
 
        while (1) {
-               health_code_update(&health_thread_kernel);
+               health_code_update();
 
                if (update_poll_flag == 1) {
                        /* Clean events object. We are about to populate it again. */
                        lttng_poll_clean(&events);
 
-                       ret = create_thread_poll_set(&events, 2);
+                       ret = sessiond_set_thread_pollset(&events, 2);
                        if (ret < 0) {
                                goto error_poll_create;
                        }
@@ -748,13 +1087,15 @@ static void *thread_manage_kernel(void *data)
                        update_poll_flag = 0;
                }
 
-               DBG("Thread kernel polling on %d fds", LTTNG_POLL_GETNB(&events));
+               DBG("Thread kernel polling");
 
                /* Poll infinite value of time */
        restart:
-               health_poll_update(&health_thread_kernel);
+               health_poll_entry();
                ret = lttng_poll_wait(&events, -1);
-               health_poll_update(&health_thread_kernel);
+               DBG("Thread kernel return from poll on %d fds",
+                               LTTNG_POLL_GETNB(&events));
+               health_poll_exit();
                if (ret < 0) {
                        /*
                         * Restart interrupted system call.
@@ -777,10 +1118,15 @@ static void *thread_manage_kernel(void *data)
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
-                       health_code_update(&health_thread_kernel);
+                       health_code_update();
+
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
 
                        /* Thread quit pipe has been closed. Killing thread. */
-                       ret = check_thread_quit_pipe(pollfd, revents);
+                       ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
                                err = 0;
                                goto exit;
@@ -788,9 +1134,8 @@ static void *thread_manage_kernel(void *data)
 
                        /* Check for data on kernel pipe */
                        if (pollfd == kernel_poll_pipe[0] && (revents & LPOLLIN)) {
-                               do {
-                                       ret = read(kernel_poll_pipe[0], &tmp, 1);
-                               } while (ret < 0 && errno == EINTR);
+                               (void) lttng_read(kernel_poll_pipe[0],
+                                       &tmp, 1);
                                /*
                                 * Ret value is useless here, if this pipe gets any actions an
                                 * update is required anyway.
@@ -825,12 +1170,12 @@ error_testpoint:
        utils_close_pipe(kernel_poll_pipe);
        kernel_poll_pipe[0] = kernel_poll_pipe[1] = -1;
        if (err) {
-               health_error(&health_thread_kernel);
+               health_error();
                ERR("Health error occurred in %s", __func__);
                WARN("Kernel thread died unexpectedly. "
                                "Kernel tracing can continue but CPU hotplug is disabled.");
        }
-       health_unregister();
+       health_unregister(health_sessiond);
        DBG("Kernel thread dying");
        return NULL;
 }
@@ -863,7 +1208,7 @@ static void signal_consumer_condition(struct consumer_data *data, int state)
  */
 static void *thread_manage_consumer(void *data)
 {
-       int sock = -1, i, ret, pollfd, err = -1;
+       int sock = -1, i, ret, pollfd, err = -1, should_quit = 0;
        uint32_t revents, nb_fd;
        enum lttcomm_return_code code;
        struct lttng_poll_event events;
@@ -871,32 +1216,18 @@ static void *thread_manage_consumer(void *data)
 
        DBG("[thread] Manage consumer started");
 
-       health_register(HEALTH_TYPE_CONSUMER);
+       rcu_register_thread();
+       rcu_thread_online();
 
-       /*
-        * Since the consumer thread can be spawned at any moment in time, we init
-        * the health to a poll status (1, which is a valid health over time).
-        * When the thread starts, we update here the health to a "code" path being
-        * an even value so this thread, when reaching a poll wait, does not
-        * trigger an error with an even value.
-        *
-        * Here is the use case we avoid.
-        *
-        * +1: the first poll update during initialization (main())
-        * +2 * x: multiple code update once in this thread.
-        * +1: poll wait in this thread (being a good health state).
-        * == even number which after the wait period shows as a bad health.
-        *
-        * In a nutshell, the following poll update to the health state brings back
-        * the state to an even value meaning a code path.
-        */
-       health_poll_update(&consumer_data->health);
+       health_register(health_sessiond, HEALTH_SESSIOND_TYPE_CONSUMER);
+
+       health_code_update();
 
        /*
-        * Pass 2 as size here for the thread quit pipe and kconsumerd_err_sock.
-        * Nothing more will be added to this poll set.
+        * Pass 3 as size here for the thread quit pipe, consumerd_err_sock and the
+        * metadata_sock. Nothing more will be added to this poll set.
         */
-       ret = create_thread_poll_set(&events, 2);
+       ret = sessiond_set_thread_pollset(&events, 3);
        if (ret < 0) {
                goto error_poll;
        }
@@ -911,18 +1242,18 @@ static void *thread_manage_consumer(void *data)
                goto error;
        }
 
-       health_code_update(&consumer_data->health);
+       health_code_update();
 
-       /* Inifinite blocking call, waiting for transmission */
+       /* Infinite blocking call, waiting for transmission */
 restart:
-       health_poll_update(&consumer_data->health);
+       health_poll_entry();
 
-       if (testpoint(thread_manage_consumer)) {
+       if (testpoint(sessiond_thread_manage_consumer)) {
                goto error;
        }
 
        ret = lttng_poll_wait(&events, -1);
-       health_poll_update(&consumer_data->health);
+       health_poll_exit();
        if (ret < 0) {
                /*
                 * Restart interrupted system call.
@@ -940,10 +1271,15 @@ restart:
                revents = LTTNG_POLL_GETEV(&events, i);
                pollfd = LTTNG_POLL_GETFD(&events, i);
 
-               health_code_update(&consumer_data->health);
+               health_code_update();
+
+               if (!revents) {
+                       /* No activity for this FD (poll implementation). */
+                       continue;
+               }
 
                /* Thread quit pipe has been closed. Killing thread. */
-               ret = check_thread_quit_pipe(pollfd, revents);
+               ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                if (ret) {
                        err = 0;
                        goto exit;
@@ -969,7 +1305,7 @@ restart:
         */
        (void) utils_set_fd_cloexec(sock);
 
-       health_code_update(&consumer_data->health);
+       health_code_update();
 
        DBG2("Receiving code from consumer err_sock");
 
@@ -980,114 +1316,180 @@ restart:
                goto error;
        }
 
-       health_code_update(&consumer_data->health);
-
+       health_code_update();
        if (code == LTTCOMM_CONSUMERD_COMMAND_SOCK_READY) {
+               /* Connect both socket, command and metadata. */
                consumer_data->cmd_sock =
                        lttcomm_connect_unix_sock(consumer_data->cmd_unix_sock_path);
-               if (consumer_data->cmd_sock < 0) {
+               consumer_data->metadata_fd =
+                       lttcomm_connect_unix_sock(consumer_data->cmd_unix_sock_path);
+               if (consumer_data->cmd_sock < 0
+                               || consumer_data->metadata_fd < 0) {
+                       PERROR("consumer connect cmd socket");
                        /* On error, signal condition and quit. */
                        signal_consumer_condition(consumer_data, -1);
-                       PERROR("consumer connect");
                        goto error;
                }
+               consumer_data->metadata_sock.fd_ptr = &consumer_data->metadata_fd;
+               /* Create metadata socket lock. */
+               consumer_data->metadata_sock.lock = zmalloc(sizeof(pthread_mutex_t));
+               if (consumer_data->metadata_sock.lock == NULL) {
+                       PERROR("zmalloc pthread mutex");
+                       ret = -1;
+                       goto error;
+               }
+               pthread_mutex_init(consumer_data->metadata_sock.lock, NULL);
+
                signal_consumer_condition(consumer_data, 1);
-               DBG("Consumer command socket ready");
+               DBG("Consumer command socket ready (fd: %d", consumer_data->cmd_sock);
+               DBG("Consumer metadata socket ready (fd: %d)",
+                               consumer_data->metadata_fd);
        } else {
                ERR("consumer error when waiting for SOCK_READY : %s",
                                lttcomm_get_readable_code(-code));
                goto error;
        }
 
-       /* Remove the kconsumerd error sock since we've established a connexion */
+       /* Remove the consumerd error sock since we've established a connexion */
        ret = lttng_poll_del(&events, consumer_data->err_sock);
        if (ret < 0) {
                goto error;
        }
 
+       /* Add new accepted error socket. */
        ret = lttng_poll_add(&events, sock, LPOLLIN | LPOLLRDHUP);
        if (ret < 0) {
                goto error;
        }
 
-       health_code_update(&consumer_data->health);
-
-       /* Inifinite blocking call, waiting for transmission */
-restart_poll:
-       health_poll_update(&consumer_data->health);
-       ret = lttng_poll_wait(&events, -1);
-       health_poll_update(&consumer_data->health);
+       /* Add metadata socket that is successfully connected. */
+       ret = lttng_poll_add(&events, consumer_data->metadata_fd,
+                       LPOLLIN | LPOLLRDHUP);
        if (ret < 0) {
-               /*
-                * Restart interrupted system call.
-                */
-               if (errno == EINTR) {
-                       goto restart_poll;
-               }
                goto error;
        }
 
-       nb_fd = ret;
-
-       for (i = 0; i < nb_fd; i++) {
-               /* Fetch once the poll data */
-               revents = LTTNG_POLL_GETEV(&events, i);
-               pollfd = LTTNG_POLL_GETFD(&events, i);
+       health_code_update();
 
-               health_code_update(&consumer_data->health);
+       /* Infinite blocking call, waiting for transmission */
+restart_poll:
+       while (1) {
+               health_code_update();
 
-               /* Thread quit pipe has been closed. Killing thread. */
-               ret = check_thread_quit_pipe(pollfd, revents);
-               if (ret) {
+               /* Exit the thread because the thread quit pipe has been triggered. */
+               if (should_quit) {
+                       /* Not a health error. */
                        err = 0;
                        goto exit;
                }
 
-               /* Event on the kconsumerd socket */
-               if (pollfd == sock) {
-                       if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
-                               ERR("consumer err socket second poll error");
-                               goto error;
+               health_poll_entry();
+               ret = lttng_poll_wait(&events, -1);
+               health_poll_exit();
+               if (ret < 0) {
+                       /*
+                        * Restart interrupted system call.
+                        */
+                       if (errno == EINTR) {
+                               goto restart_poll;
                        }
+                       goto error;
                }
-       }
-
-       health_code_update(&consumer_data->health);
 
-       /* Wait for any kconsumerd error */
-       ret = lttcomm_recv_unix_sock(sock, &code,
-                       sizeof(enum lttcomm_return_code));
-       if (ret <= 0) {
-               ERR("consumer closed the command socket");
-               goto error;
-       }
+               nb_fd = ret;
 
-       ERR("consumer return code : %s", lttcomm_get_readable_code(-code));
+               for (i = 0; i < nb_fd; i++) {
+                       /* Fetch once the poll data */
+                       revents = LTTNG_POLL_GETEV(&events, i);
+                       pollfd = LTTNG_POLL_GETFD(&events, i);
 
-exit:
-error:
-       /* Immediately set the consumerd state to stopped */
-       if (consumer_data->type == LTTNG_CONSUMER_KERNEL) {
-               uatomic_set(&kernel_consumerd_state, CONSUMER_ERROR);
-       } else if (consumer_data->type == LTTNG_CONSUMER64_UST ||
-                       consumer_data->type == LTTNG_CONSUMER32_UST) {
-               uatomic_set(&ust_consumerd_state, CONSUMER_ERROR);
-       } else {
-               /* Code flow error... */
-               assert(0);
-       }
+                       health_code_update();
+
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
+                       /*
+                        * Thread quit pipe has been triggered, flag that we should stop
+                        * but continue the current loop to handle potential data from
+                        * consumer.
+                        */
+                       should_quit = sessiond_check_thread_quit_pipe(pollfd, revents);
+
+                       if (pollfd == sock) {
+                               /* Event on the consumerd socket */
+                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                                       ERR("consumer err socket second poll error");
+                                       goto error;
+                               }
+                               health_code_update();
+                               /* Wait for any kconsumerd error */
+                               ret = lttcomm_recv_unix_sock(sock, &code,
+                                               sizeof(enum lttcomm_return_code));
+                               if (ret <= 0) {
+                                       ERR("consumer closed the command socket");
+                                       goto error;
+                               }
+
+                               ERR("consumer return code : %s",
+                                               lttcomm_get_readable_code(-code));
+
+                               goto exit;
+                       } else if (pollfd == consumer_data->metadata_fd) {
+                               /* UST metadata requests */
+                               ret = ust_consumer_metadata_request(
+                                               &consumer_data->metadata_sock);
+                               if (ret < 0) {
+                                       ERR("Handling metadata request");
+                                       goto error;
+                               }
+                       }
+                       /* No need for an else branch all FDs are tested prior. */
+               }
+               health_code_update();
+       }
+
+exit:
+error:
+       /*
+        * We lock here because we are about to close the sockets and some other
+        * thread might be using them so get exclusive access which will abort all
+        * other consumer command by other threads.
+        */
+       pthread_mutex_lock(&consumer_data->lock);
+
+       /* Immediately set the consumerd state to stopped */
+       if (consumer_data->type == LTTNG_CONSUMER_KERNEL) {
+               uatomic_set(&kernel_consumerd_state, CONSUMER_ERROR);
+       } else if (consumer_data->type == LTTNG_CONSUMER64_UST ||
+                       consumer_data->type == LTTNG_CONSUMER32_UST) {
+               uatomic_set(&ust_consumerd_state, CONSUMER_ERROR);
+       } else {
+               /* Code flow error... */
+               assert(0);
+       }
 
        if (consumer_data->err_sock >= 0) {
                ret = close(consumer_data->err_sock);
                if (ret) {
                        PERROR("close");
                }
+               consumer_data->err_sock = -1;
        }
        if (consumer_data->cmd_sock >= 0) {
                ret = close(consumer_data->cmd_sock);
                if (ret) {
                        PERROR("close");
                }
+               consumer_data->cmd_sock = -1;
+       }
+       if (consumer_data->metadata_sock.fd_ptr &&
+           *consumer_data->metadata_sock.fd_ptr >= 0) {
+               ret = close(*consumer_data->metadata_sock.fd_ptr);
+               if (ret) {
+                       PERROR("close");
+               }
        }
        if (sock >= 0) {
                ret = close(sock);
@@ -1099,16 +1501,25 @@ error:
        unlink(consumer_data->err_unix_sock_path);
        unlink(consumer_data->cmd_unix_sock_path);
        consumer_data->pid = 0;
+       pthread_mutex_unlock(&consumer_data->lock);
 
+       /* Cleanup metadata socket mutex. */
+       if (consumer_data->metadata_sock.lock) {
+               pthread_mutex_destroy(consumer_data->metadata_sock.lock);
+               free(consumer_data->metadata_sock.lock);
+       }
        lttng_poll_clean(&events);
 error_poll:
        if (err) {
-               health_error(&consumer_data->health);
+               health_error();
                ERR("Health error occurred in %s", __func__);
        }
-       health_unregister();
+       health_unregister(health_sessiond);
        DBG("consumer thread cleanup completed");
 
+       rcu_thread_offline();
+       rcu_unregister_thread();
+
        return NULL;
 }
 
@@ -1118,8 +1529,8 @@ error_poll:
 static void *thread_manage_apps(void *data)
 {
        int i, ret, pollfd, err = -1;
+       ssize_t size_ret;
        uint32_t revents, nb_fd;
-       struct ust_command ust_cmd;
        struct lttng_poll_event events;
 
        DBG("[thread] Manage application started");
@@ -1127,15 +1538,15 @@ static void *thread_manage_apps(void *data)
        rcu_register_thread();
        rcu_thread_online();
 
-       health_register(HEALTH_TYPE_APP_MANAGE);
+       health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_MANAGE);
 
-       if (testpoint(thread_manage_apps)) {
+       if (testpoint(sessiond_thread_manage_apps)) {
                goto error_testpoint;
        }
 
-       health_code_update(&health_thread_app_manage);
+       health_code_update();
 
-       ret = create_thread_poll_set(&events, 2);
+       ret = sessiond_set_thread_pollset(&events, 2);
        if (ret < 0) {
                goto error_poll_create;
        }
@@ -1145,20 +1556,22 @@ static void *thread_manage_apps(void *data)
                goto error;
        }
 
-       if (testpoint(thread_manage_apps_before_loop)) {
+       if (testpoint(sessiond_thread_manage_apps_before_loop)) {
                goto error;
        }
 
-       health_code_update(&health_thread_app_manage);
+       health_code_update();
 
        while (1) {
-               DBG("Apps thread polling on %d fds", LTTNG_POLL_GETNB(&events));
+               DBG("Apps thread polling");
 
                /* Inifinite blocking call, waiting for transmission */
        restart:
-               health_poll_update(&health_thread_app_manage);
+               health_poll_entry();
                ret = lttng_poll_wait(&events, -1);
-               health_poll_update(&health_thread_app_manage);
+               DBG("Apps thread return from poll on %d fds",
+                               LTTNG_POLL_GETNB(&events));
+               health_poll_exit();
                if (ret < 0) {
                        /*
                         * Restart interrupted system call.
@@ -1176,10 +1589,15 @@ static void *thread_manage_apps(void *data)
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
-                       health_code_update(&health_thread_app_manage);
+                       health_code_update();
+
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
 
                        /* Thread quit pipe has been closed. Killing thread. */
-                       ret = check_thread_quit_pipe(pollfd, revents);
+                       ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
                                err = 0;
                                goto exit;
@@ -1191,74 +1609,29 @@ static void *thread_manage_apps(void *data)
                                        ERR("Apps command pipe error");
                                        goto error;
                                } else if (revents & LPOLLIN) {
+                                       int sock;
+
                                        /* Empty pipe */
-                                       do {
-                                               ret = read(apps_cmd_pipe[0], &ust_cmd, sizeof(ust_cmd));
-                                       } while (ret < 0 && errno == EINTR);
-                                       if (ret < 0 || ret < sizeof(ust_cmd)) {
+                                       size_ret = lttng_read(apps_cmd_pipe[0], &sock, sizeof(sock));
+                                       if (size_ret < sizeof(sock)) {
                                                PERROR("read apps cmd pipe");
                                                goto error;
                                        }
 
-                                       health_code_update(&health_thread_app_manage);
-
-                                       /* Register applicaton to the session daemon */
-                                       ret = ust_app_register(&ust_cmd.reg_msg,
-                                                       ust_cmd.sock);
-                                       if (ret == -ENOMEM) {
-                                               goto error;
-                                       } else if (ret < 0) {
-                                               break;
-                                       }
-
-                                       health_code_update(&health_thread_app_manage);
+                                       health_code_update();
 
                                        /*
-                                        * Validate UST version compatibility.
+                                        * We only monitor the error events of the socket. This
+                                        * thread does not handle any incoming data from UST
+                                        * (POLLIN).
                                         */
-                                       ret = ust_app_validate_version(ust_cmd.sock);
-                                       if (ret >= 0) {
-                                               /*
-                                                * Add channel(s) and event(s) to newly registered apps
-                                                * from lttng global UST domain.
-                                                */
-                                               update_ust_app(ust_cmd.sock);
-                                       }
-
-                                       health_code_update(&health_thread_app_manage);
-
-                                       ret = ust_app_register_done(ust_cmd.sock);
+                                       ret = lttng_poll_add(&events, sock,
+                                                       LPOLLERR | LPOLLHUP | LPOLLRDHUP);
                                        if (ret < 0) {
-                                               /*
-                                                * If the registration is not possible, we simply
-                                                * unregister the apps and continue
-                                                */
-                                               ust_app_unregister(ust_cmd.sock);
-                                       } else {
-                                               /*
-                                                * We only monitor the error events of the socket. This
-                                                * thread does not handle any incoming data from UST
-                                                * (POLLIN).
-                                                */
-                                               ret = lttng_poll_add(&events, ust_cmd.sock,
-                                                               LPOLLERR & LPOLLHUP & LPOLLRDHUP);
-                                               if (ret < 0) {
-                                                       goto error;
-                                               }
-
-                                               /* Set socket timeout for both receiving and ending */
-                                               (void) lttcomm_setsockopt_rcv_timeout(ust_cmd.sock,
-                                                               app_socket_timeout);
-                                               (void) lttcomm_setsockopt_snd_timeout(ust_cmd.sock,
-                                                               app_socket_timeout);
-
-                                               DBG("Apps with sock %d added to poll set",
-                                                               ust_cmd.sock);
+                                               goto error;
                                        }
 
-                                       health_code_update(&health_thread_app_manage);
-
-                                       break;
+                                       DBG("Apps with sock %d added to poll set", sock);
                                }
                        } else {
                                /*
@@ -1274,11 +1647,10 @@ static void *thread_manage_apps(void *data)
 
                                        /* Socket closed on remote end. */
                                        ust_app_unregister(pollfd);
-                                       break;
                                }
                        }
 
-                       health_code_update(&health_thread_app_manage);
+                       health_code_update();
                }
        }
 
@@ -1297,35 +1669,190 @@ error_testpoint:
         */
 
        if (err) {
-               health_error(&health_thread_app_manage);
+               health_error();
                ERR("Health error occurred in %s", __func__);
        }
-       health_unregister();
+       health_unregister(health_sessiond);
        DBG("Application communication apps thread cleanup complete");
        rcu_thread_offline();
        rcu_unregister_thread();
        return NULL;
 }
 
+/*
+ * Send a socket to a thread This is called from the dispatch UST registration
+ * thread once all sockets are set for the application.
+ *
+ * The sock value can be invalid, we don't really care, the thread will handle
+ * it and make the necessary cleanup if so.
+ *
+ * On success, return 0 else a negative value being the errno message of the
+ * write().
+ */
+static int send_socket_to_thread(int fd, int sock)
+{
+       ssize_t ret;
+
+       /*
+        * It's possible that the FD is set as invalid with -1 concurrently just
+        * before calling this function being a shutdown state of the thread.
+        */
+       if (fd < 0) {
+               ret = -EBADF;
+               goto error;
+       }
+
+       ret = lttng_write(fd, &sock, sizeof(sock));
+       if (ret < sizeof(sock)) {
+               PERROR("write apps pipe %d", fd);
+               if (ret < 0) {
+                       ret = -errno;
+               }
+               goto error;
+       }
+
+       /* All good. Don't send back the write positive ret value. */
+       ret = 0;
+error:
+       return (int) ret;
+}
+
+/*
+ * Sanitize the wait queue of the dispatch registration thread meaning removing
+ * invalid nodes from it. This is to avoid memory leaks for the case the UST
+ * notify socket is never received.
+ */
+static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue)
+{
+       int ret, nb_fd = 0, i;
+       unsigned int fd_added = 0;
+       struct lttng_poll_event events;
+       struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node;
+
+       assert(wait_queue);
+
+       lttng_poll_init(&events);
+
+       /* Just skip everything for an empty queue. */
+       if (!wait_queue->count) {
+               goto end;
+       }
+
+       ret = lttng_poll_create(&events, wait_queue->count, LTTNG_CLOEXEC);
+       if (ret < 0) {
+               goto error_create;
+       }
+
+       cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
+                       &wait_queue->head, head) {
+               assert(wait_node->app);
+               ret = lttng_poll_add(&events, wait_node->app->sock,
+                               LPOLLHUP | LPOLLERR);
+               if (ret < 0) {
+                       goto error;
+               }
+
+               fd_added = 1;
+       }
+
+       if (!fd_added) {
+               goto end;
+       }
+
+       /*
+        * Poll but don't block so we can quickly identify the faulty events and
+        * clean them afterwards from the wait queue.
+        */
+       ret = lttng_poll_wait(&events, 0);
+       if (ret < 0) {
+               goto error;
+       }
+       nb_fd = ret;
+
+       for (i = 0; i < nb_fd; i++) {
+               /* Get faulty FD. */
+               uint32_t revents = LTTNG_POLL_GETEV(&events, i);
+               int pollfd = LTTNG_POLL_GETFD(&events, i);
+
+               if (!revents) {
+                       /* No activity for this FD (poll implementation). */
+                       continue;
+               }
+
+               cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
+                               &wait_queue->head, head) {
+                       if (pollfd == wait_node->app->sock &&
+                                       (revents & (LPOLLHUP | LPOLLERR))) {
+                               cds_list_del(&wait_node->head);
+                               wait_queue->count--;
+                               ust_app_destroy(wait_node->app);
+                               free(wait_node);
+                               break;
+                       }
+               }
+       }
+
+       if (nb_fd > 0) {
+               DBG("Wait queue sanitized, %d node were cleaned up", nb_fd);
+       }
+
+end:
+       lttng_poll_clean(&events);
+       return;
+
+error:
+       lttng_poll_clean(&events);
+error_create:
+       ERR("Unable to sanitize wait queue");
+       return;
+}
+
 /*
  * Dispatch request from the registration threads to the application
  * communication thread.
  */
 static void *thread_dispatch_ust_registration(void *data)
 {
-       int ret;
-       struct cds_wfq_node *node;
+       int ret, err = -1;
+       struct cds_wfcq_node *node;
        struct ust_command *ust_cmd = NULL;
+       struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node;
+       struct ust_reg_wait_queue wait_queue = {
+               .count = 0,
+       };
+
+       health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG_DISPATCH);
+
+       if (testpoint(sessiond_thread_app_reg_dispatch)) {
+               goto error_testpoint;
+       }
+
+       health_code_update();
+
+       CDS_INIT_LIST_HEAD(&wait_queue.head);
 
        DBG("[thread] Dispatch UST command started");
 
        while (!CMM_LOAD_SHARED(dispatch_thread_exit)) {
+               health_code_update();
+
                /* Atomically prepare the queue futex */
                futex_nto1_prepare(&ust_cmd_queue.futex);
 
                do {
+                       struct ust_app *app = NULL;
+                       ust_cmd = NULL;
+
+                       /*
+                        * Make sure we don't have node(s) that have hung up before receiving
+                        * the notify socket. This is to clean the list in order to avoid
+                        * memory leaks from notify socket that are never seen.
+                        */
+                       sanitize_wait_queue(&wait_queue);
+
+                       health_code_update();
                        /* Dequeue command for registration */
-                       node = cds_wfq_dequeue_blocking(&ust_cmd_queue.queue);
+                       node = cds_wfcq_dequeue_blocking(&ust_cmd_queue.head, &ust_cmd_queue.tail);
                        if (node == NULL) {
                                DBG("Woken up but nothing in the UST command queue");
                                /* Continue thread execution */
@@ -1340,44 +1867,193 @@ static void *thread_dispatch_ust_registration(void *data)
                                        ust_cmd->reg_msg.uid, ust_cmd->reg_msg.gid,
                                        ust_cmd->sock, ust_cmd->reg_msg.name,
                                        ust_cmd->reg_msg.major, ust_cmd->reg_msg.minor);
-                       /*
-                        * Inform apps thread of the new application registration. This
-                        * call is blocking so we can be assured that the data will be read
-                        * at some point in time or wait to the end of the world :)
-                        */
-                       if (apps_cmd_pipe[1] >= 0) {
-                               do {
-                                       ret = write(apps_cmd_pipe[1], ust_cmd,
-                                                       sizeof(struct ust_command));
-                               } while (ret < 0 && errno == EINTR);
-                               if (ret < 0 || ret != sizeof(struct ust_command)) {
-                                       PERROR("write apps cmd pipe");
-                                       if (errno == EBADF) {
-                                               /*
-                                                * We can't inform the application thread to process
-                                                * registration. We will exit or else application
-                                                * registration will not occur and tracing will never
-                                                * start.
-                                                */
-                                               goto error;
+
+                       if (ust_cmd->reg_msg.type == USTCTL_SOCKET_CMD) {
+                               wait_node = zmalloc(sizeof(*wait_node));
+                               if (!wait_node) {
+                                       PERROR("zmalloc wait_node dispatch");
+                                       ret = close(ust_cmd->sock);
+                                       if (ret < 0) {
+                                               PERROR("close ust sock dispatch %d", ust_cmd->sock);
+                                       }
+                                       lttng_fd_put(LTTNG_FD_APPS, 1);
+                                       free(ust_cmd);
+                                       goto error;
+                               }
+                               CDS_INIT_LIST_HEAD(&wait_node->head);
+
+                               /* Create application object if socket is CMD. */
+                               wait_node->app = ust_app_create(&ust_cmd->reg_msg,
+                                               ust_cmd->sock);
+                               if (!wait_node->app) {
+                                       ret = close(ust_cmd->sock);
+                                       if (ret < 0) {
+                                               PERROR("close ust sock dispatch %d", ust_cmd->sock);
                                        }
+                                       lttng_fd_put(LTTNG_FD_APPS, 1);
+                                       free(wait_node);
+                                       free(ust_cmd);
+                                       continue;
                                }
+                               /*
+                                * Add application to the wait queue so we can set the notify
+                                * socket before putting this object in the global ht.
+                                */
+                               cds_list_add(&wait_node->head, &wait_queue.head);
+                               wait_queue.count++;
+
+                               free(ust_cmd);
+                               /*
+                                * We have to continue here since we don't have the notify
+                                * socket and the application MUST be added to the hash table
+                                * only at that moment.
+                                */
+                               continue;
                        } else {
-                               /* Application manager thread is not available. */
-                               ret = close(ust_cmd->sock);
+                               /*
+                                * Look for the application in the local wait queue and set the
+                                * notify socket if found.
+                                */
+                               cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
+                                               &wait_queue.head, head) {
+                                       health_code_update();
+                                       if (wait_node->app->pid == ust_cmd->reg_msg.pid) {
+                                               wait_node->app->notify_sock = ust_cmd->sock;
+                                               cds_list_del(&wait_node->head);
+                                               wait_queue.count--;
+                                               app = wait_node->app;
+                                               free(wait_node);
+                                               DBG3("UST app notify socket %d is set", ust_cmd->sock);
+                                               break;
+                                       }
+                               }
+
+                               /*
+                                * With no application at this stage the received socket is
+                                * basically useless so close it before we free the cmd data
+                                * structure for good.
+                                */
+                               if (!app) {
+                                       ret = close(ust_cmd->sock);
+                                       if (ret < 0) {
+                                               PERROR("close ust sock dispatch %d", ust_cmd->sock);
+                                       }
+                                       lttng_fd_put(LTTNG_FD_APPS, 1);
+                               }
+                               free(ust_cmd);
+                       }
+
+                       if (app) {
+                               /*
+                                * @session_lock_list
+                                *
+                                * Lock the global session list so from the register up to the
+                                * registration done message, no thread can see the application
+                                * and change its state.
+                                */
+                               session_lock_list();
+                               rcu_read_lock();
+
+                               /*
+                                * Add application to the global hash table. This needs to be
+                                * done before the update to the UST registry can locate the
+                                * application.
+                                */
+                               ust_app_add(app);
+
+                               /* Set app version. This call will print an error if needed. */
+                               (void) ust_app_version(app);
+
+                               /* Send notify socket through the notify pipe. */
+                               ret = send_socket_to_thread(apps_cmd_notify_pipe[1],
+                                               app->notify_sock);
+                               if (ret < 0) {
+                                       rcu_read_unlock();
+                                       session_unlock_list();
+                                       /*
+                                        * No notify thread, stop the UST tracing. However, this is
+                                        * not an internal error of the this thread thus setting
+                                        * the health error code to a normal exit.
+                                        */
+                                       err = 0;
+                                       goto error;
+                               }
+
+                               /*
+                                * Update newly registered application with the tracing
+                                * registry info already enabled information.
+                                */
+                               update_ust_app(app->sock);
+
+                               /*
+                                * Don't care about return value. Let the manage apps threads
+                                * handle app unregistration upon socket close.
+                                */
+                               (void) ust_app_register_done(app->sock);
+
+                               /*
+                                * Even if the application socket has been closed, send the app
+                                * to the thread and unregistration will take place at that
+                                * place.
+                                */
+                               ret = send_socket_to_thread(apps_cmd_pipe[1], app->sock);
                                if (ret < 0) {
-                                       PERROR("close ust_cmd sock");
+                                       rcu_read_unlock();
+                                       session_unlock_list();
+                                       /*
+                                        * No apps. thread, stop the UST tracing. However, this is
+                                        * not an internal error of the this thread thus setting
+                                        * the health error code to a normal exit.
+                                        */
+                                       err = 0;
+                                       goto error;
                                }
+
+                               rcu_read_unlock();
+                               session_unlock_list();
                        }
-                       free(ust_cmd);
                } while (node != NULL);
 
+               health_poll_entry();
                /* Futex wait on queue. Blocking call on futex() */
                futex_nto1_wait(&ust_cmd_queue.futex);
+               health_poll_exit();
        }
+       /* Normal exit, no error */
+       err = 0;
 
 error:
+       /* Clean up wait queue. */
+       cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
+                       &wait_queue.head, head) {
+               cds_list_del(&wait_node->head);
+               wait_queue.count--;
+               free(wait_node);
+       }
+
+       /* Empty command queue. */
+       for (;;) {
+               /* Dequeue command for registration */
+               node = cds_wfcq_dequeue_blocking(&ust_cmd_queue.head, &ust_cmd_queue.tail);
+               if (node == NULL) {
+                       break;
+               }
+               ust_cmd = caa_container_of(node, struct ust_command, node);
+               ret = close(ust_cmd->sock);
+               if (ret < 0) {
+                       PERROR("close ust sock exit dispatch %d", ust_cmd->sock);
+               }
+               lttng_fd_put(LTTNG_FD_APPS, 1);
+               free(ust_cmd);
+       }
+
+error_testpoint:
        DBG("Dispatch thread dying");
+       if (err) {
+               health_error();
+               ERR("Health error occurred in %s", __func__);
+       }
+       health_unregister(health_sessiond);
        return NULL;
 }
 
@@ -1397,9 +2073,9 @@ static void *thread_registration_apps(void *data)
 
        DBG("[thread] Manage application registration started");
 
-       health_register(HEALTH_TYPE_APP_REG);
+       health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG);
 
-       if (testpoint(thread_registration_apps)) {
+       if (testpoint(sessiond_thread_registration_apps)) {
                goto error_testpoint;
        }
 
@@ -1412,7 +2088,7 @@ static void *thread_registration_apps(void *data)
         * Pass 2 as size here for the thread quit pipe and apps socket. Nothing
         * more will be added to this poll set.
         */
-       ret = create_thread_poll_set(&events, 2);
+       ret = sessiond_set_thread_pollset(&events, 2);
        if (ret < 0) {
                goto error_create_poll;
        }
@@ -1436,9 +2112,9 @@ static void *thread_registration_apps(void *data)
 
                /* Inifinite blocking call, waiting for transmission */
        restart:
-               health_poll_update(&health_thread_app_reg);
+               health_poll_entry();
                ret = lttng_poll_wait(&events, -1);
-               health_poll_update(&health_thread_app_reg);
+               health_poll_exit();
                if (ret < 0) {
                        /*
                         * Restart interrupted system call.
@@ -1452,14 +2128,19 @@ static void *thread_registration_apps(void *data)
                nb_fd = ret;
 
                for (i = 0; i < nb_fd; i++) {
-                       health_code_update(&health_thread_app_reg);
+                       health_code_update();
 
                        /* Fetch once the poll data */
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
-                       ret = check_thread_quit_pipe(pollfd, revents);
+                       ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
                                err = 0;
                                goto exit;
@@ -1476,6 +2157,18 @@ static void *thread_registration_apps(void *data)
                                                goto error;
                                        }
 
+                                       /*
+                                        * Set socket timeout for both receiving and ending.
+                                        * app_socket_timeout is in seconds, whereas
+                                        * lttcomm_setsockopt_rcv_timeout and
+                                        * lttcomm_setsockopt_snd_timeout expect msec as
+                                        * parameter.
+                                        */
+                                       (void) lttcomm_setsockopt_rcv_timeout(sock,
+                                                       app_socket_timeout * 1000);
+                                       (void) lttcomm_setsockopt_snd_timeout(sock,
+                                                       app_socket_timeout * 1000);
+
                                        /*
                                         * Set the CLOEXEC flag. Return code is useless because
                                         * either way, the show must go on.
@@ -1486,6 +2179,10 @@ static void *thread_registration_apps(void *data)
                                        ust_cmd = zmalloc(sizeof(struct ust_command));
                                        if (ust_cmd == NULL) {
                                                PERROR("ust command zmalloc");
+                                               ret = close(sock);
+                                               if (ret) {
+                                                       PERROR("close");
+                                               }
                                                goto error;
                                        }
 
@@ -1504,16 +2201,12 @@ static void *thread_registration_apps(void *data)
                                                sock = -1;
                                                continue;
                                        }
-                                       health_code_update(&health_thread_app_reg);
-                                       ret = lttcomm_recv_unix_sock(sock, &ust_cmd->reg_msg,
-                                                       sizeof(struct ust_register_msg));
-                                       if (ret < 0 || ret < sizeof(struct ust_register_msg)) {
-                                               if (ret < 0) {
-                                                       PERROR("lttcomm_recv_unix_sock register apps");
-                                               } else {
-                                                       ERR("Wrong size received on apps register");
-                                               }
+
+                                       health_code_update();
+                                       ret = ust_app_recv_registration(sock, &ust_cmd->reg_msg);
+                                       if (ret < 0) {
                                                free(ust_cmd);
+                                               /* Close socket of the application. */
                                                ret = close(sock);
                                                if (ret) {
                                                        PERROR("close");
@@ -1522,7 +2215,7 @@ static void *thread_registration_apps(void *data)
                                                sock = -1;
                                                continue;
                                        }
-                                       health_code_update(&health_thread_app_reg);
+                                       health_code_update();
 
                                        ust_cmd->sock = sock;
                                        sock = -1;
@@ -1538,11 +2231,11 @@ static void *thread_registration_apps(void *data)
                                         * Lock free enqueue the registration request. The red pill
                                         * has been taken! This apps will be part of the *system*.
                                         */
-                                       cds_wfq_enqueue(&ust_cmd_queue.queue, &ust_cmd->node);
+                                       cds_wfcq_enqueue(&ust_cmd_queue.head, &ust_cmd_queue.tail, &ust_cmd->node);
 
                                        /*
                                         * Wake the registration queue futex. Implicit memory
-                                        * barrier with the exchange in cds_wfq_enqueue.
+                                        * barrier with the exchange in cds_wfcq_enqueue.
                                         */
                                        futex_nto1_wake(&ust_cmd_queue.futex);
                                }
@@ -1552,11 +2245,6 @@ static void *thread_registration_apps(void *data)
 
 exit:
 error:
-       if (err) {
-               health_error(&health_thread_app_reg);
-               ERR("Health error occurred in %s", __func__);
-       }
-
        /* Notify that the registration thread is gone */
        notify_ust_apps(0);
 
@@ -1581,7 +2269,11 @@ error_listen:
 error_create_poll:
 error_testpoint:
        DBG("UST Registration thread cleanup complete");
-       health_unregister();
+       if (err) {
+               health_error();
+               ERR("Health error occurred in %s", __func__);
+       }
+       health_unregister(health_sessiond);
 
        return NULL;
 }
@@ -1600,7 +2292,7 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
 
        /* Setup pthread condition */
        ret = pthread_condattr_init(&consumer_data->condattr);
-       if (ret != 0) {
+       if (ret) {
                errno = ret;
                PERROR("pthread_condattr_init consumer data");
                goto error;
@@ -1612,14 +2304,14 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
         * for a more details and how we noticed it.
         */
        ret = pthread_condattr_setclock(&consumer_data->condattr, CLOCK_MONOTONIC);
-       if (ret != 0) {
+       if (ret) {
                errno = ret;
                PERROR("pthread_condattr_setclock consumer data");
                goto error;
        }
 
        ret = pthread_cond_init(&consumer_data->cond, &consumer_data->condattr);
-       if (ret != 0) {
+       if (ret) {
                errno = ret;
                PERROR("pthread_cond_init consumer data");
                goto error;
@@ -1627,7 +2319,8 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
 
        ret = pthread_create(&consumer_data->thread, NULL, thread_manage_consumer,
                        consumer_data);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create consumer");
                ret = -1;
                goto error;
@@ -1677,19 +2370,23 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
        if (ret != 0) {
                errno = ret;
                if (ret == ETIMEDOUT) {
+                       int pth_ret;
+
                        /*
                         * Call has timed out so we kill the kconsumerd_thread and return
                         * an error.
                         */
                        ERR("Condition timed out. The consumer thread was never ready."
                                        " Killing it");
-                       ret = pthread_cancel(consumer_data->thread);
-                       if (ret < 0) {
+                       pth_ret = pthread_cancel(consumer_data->thread);
+                       if (pth_ret < 0) {
                                PERROR("pthread_cancel consumer thread");
                        }
                } else {
                        PERROR("pthread_cond_wait failed consumer thread");
                }
+               /* Caller is expecting a negative value on failure. */
+               ret = -1;
                goto error;
        }
 
@@ -1719,7 +2416,7 @@ static int join_consumer_thread(struct consumer_data *consumer_data)
                int ret;
                ret = kill(consumer_data->pid, SIGTERM);
                if (ret) {
-                       ERR("Error killing consumer daemon");
+                       PERROR("Error killing consumer daemon");
                        return ret;
                }
                return pthread_join(consumer_data->thread, &status);
@@ -1750,9 +2447,12 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                 */
                if (opt_verbose_consumer) {
                        verbosity = "--verbose";
-               } else {
+               } else if (lttng_opt_quiet) {
                        verbosity = "--quiet";
+               } else {
+                       verbosity = "";
                }
+
                switch (consumer_data->type) {
                case LTTNG_CONSUMER_KERNEL:
                        /*
@@ -1775,13 +2475,15 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                                consumer_to_use = consumerd32_bin;
                        } else {
                                DBG("Could not find any valid consumerd executable");
+                               ret = -EINVAL;
                                break;
                        }
                        DBG("Using kernel consumer at: %s",  consumer_to_use);
-                       execl(consumer_to_use,
+                       ret = execl(consumer_to_use,
                                "lttng-consumerd", verbosity, "-k",
                                "--consumerd-cmd-sock", consumer_data->cmd_unix_sock_path,
                                "--consumerd-err-sock", consumer_data->err_unix_sock_path,
+                               "--group", tracing_group_name,
                                NULL);
                        break;
                case LTTNG_CONSUMER64_UST:
@@ -1792,7 +2494,7 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                                char *tmp;
                                size_t tmplen;
 
-                               tmp = getenv("LD_LIBRARY_PATH");
+                               tmp = lttng_secure_getenv("LD_LIBRARY_PATH");
                                if (!tmp) {
                                        tmp = "";
                                }
@@ -1812,6 +2514,7 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                                ret = putenv(tmpnew);
                                if (ret) {
                                        ret = -errno;
+                                       free(tmpnew);
                                        goto error;
                                }
                        }
@@ -1819,13 +2522,11 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                        ret = execl(consumerd64_bin, "lttng-consumerd", verbosity, "-u",
                                        "--consumerd-cmd-sock", consumer_data->cmd_unix_sock_path,
                                        "--consumerd-err-sock", consumer_data->err_unix_sock_path,
+                                       "--group", tracing_group_name,
                                        NULL);
                        if (consumerd64_libdir[0] != '\0') {
                                free(tmpnew);
                        }
-                       if (ret) {
-                               goto error;
-                       }
                        break;
                }
                case LTTNG_CONSUMER32_UST:
@@ -1836,7 +2537,7 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                                char *tmp;
                                size_t tmplen;
 
-                               tmp = getenv("LD_LIBRARY_PATH");
+                               tmp = lttng_secure_getenv("LD_LIBRARY_PATH");
                                if (!tmp) {
                                        tmp = "";
                                }
@@ -1856,6 +2557,7 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                                ret = putenv(tmpnew);
                                if (ret) {
                                        ret = -errno;
+                                       free(tmpnew);
                                        goto error;
                                }
                        }
@@ -1863,13 +2565,11 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                        ret = execl(consumerd32_bin, "lttng-consumerd", verbosity, "-u",
                                        "--consumerd-cmd-sock", consumer_data->cmd_unix_sock_path,
                                        "--consumerd-err-sock", consumer_data->err_unix_sock_path,
+                                       "--group", tracing_group_name,
                                        NULL);
                        if (consumerd32_libdir[0] != '\0') {
                                free(tmpnew);
                        }
-                       if (ret) {
-                               goto error;
-                       }
                        break;
                }
                default:
@@ -1877,8 +2577,9 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                        exit(EXIT_FAILURE);
                }
                if (errno != 0) {
-                       PERROR("kernel start consumer exec");
+                       PERROR("Consumer execl()");
                }
+               /* Reaching this point, we got a failure on our execl(). */
                exit(EXIT_FAILURE);
        } else if (pid > 0) {
                ret = pid;
@@ -1936,7 +2637,7 @@ end:
        return 0;
 
 error:
-       /* Cleanup already created socket on error. */
+       /* Cleanup already created sockets on error. */
        if (consumer_data->err_sock >= 0) {
                int err;
 
@@ -1948,21 +2649,6 @@ error:
        return ret;
 }
 
-/*
- * Compute health status of each consumer. If one of them is zero (bad
- * state), we return 0.
- */
-static int check_consumer_health(void)
-{
-       int ret;
-
-       ret = health_check_state(HEALTH_TYPE_CONSUMER);
-
-       DBG3("Health consumer check %d", ret);
-
-       return ret;
-}
-
 /*
  * Setup necessary data for kernel tracer action.
  */
@@ -2031,6 +2717,8 @@ error:
  * Copy consumer output from the tracing session to the domain session. The
  * function also applies the right modification on a per domain basis for the
  * trace files destination directory.
+ *
+ * Should *NOT* be called with RCU read-side lock held.
  */
 static int copy_session_consumer(int domain, struct ltt_session *session)
 {
@@ -2051,7 +2739,7 @@ static int copy_session_consumer(int domain, struct ltt_session *session)
                 * domain.
                 */
                if (session->kernel_session->consumer) {
-                       consumer_destroy_output(session->kernel_session->consumer);
+                       consumer_output_put(session->kernel_session->consumer);
                }
                session->kernel_session->consumer =
                        consumer_copy_output(session->consumer);
@@ -2059,10 +2747,13 @@ static int copy_session_consumer(int domain, struct ltt_session *session)
                consumer = session->kernel_session->consumer;
                dir_name = DEFAULT_KERNEL_TRACE_DIR;
                break;
+       case LTTNG_DOMAIN_JUL:
+       case LTTNG_DOMAIN_LOG4J:
+       case LTTNG_DOMAIN_PYTHON:
        case LTTNG_DOMAIN_UST:
                DBG3("Copying tracing session consumer output in UST session");
                if (session->ust_session->consumer) {
-                       consumer_destroy_output(session->ust_session->consumer);
+                       consumer_output_put(session->ust_session->consumer);
                }
                session->ust_session->consumer =
                        consumer_copy_output(session->consumer);
@@ -2088,6 +2779,8 @@ error:
 
 /*
  * Create an UST session and add it to the session ust list.
+ *
+ * Should *NOT* be called with RCU read-side lock held.
  */
 static int create_ust_session(struct ltt_session *session,
                struct lttng_domain *domain)
@@ -2100,6 +2793,9 @@ static int create_ust_session(struct ltt_session *session,
        assert(session->consumer);
 
        switch (domain->type) {
+       case LTTNG_DOMAIN_JUL:
+       case LTTNG_DOMAIN_LOG4J:
+       case LTTNG_DOMAIN_PYTHON:
        case LTTNG_DOMAIN_UST:
                break;
        default:
@@ -2110,7 +2806,7 @@ static int create_ust_session(struct ltt_session *session,
 
        DBG("Creating UST session");
 
-       lus = trace_ust_create_session(session->path, session->id);
+       lus = trace_ust_create_session(session->id);
        if (lus == NULL) {
                ret = LTTNG_ERR_UST_SESS_FAIL;
                goto error;
@@ -2118,8 +2814,20 @@ static int create_ust_session(struct ltt_session *session,
 
        lus->uid = session->uid;
        lus->gid = session->gid;
+       lus->output_traces = session->output_traces;
+       lus->snapshot_mode = session->snapshot_mode;
+       lus->live_timer_interval = session->live_timer;
        session->ust_session = lus;
-
+       if (session->shm_path[0]) {
+               strncpy(lus->root_shm_path, session->shm_path,
+                       sizeof(lus->root_shm_path));
+               lus->root_shm_path[sizeof(lus->root_shm_path) - 1] = '\0';
+               strncpy(lus->shm_path, session->shm_path,
+                       sizeof(lus->shm_path));
+               lus->shm_path[sizeof(lus->shm_path) - 1] = '\0';
+               strncat(lus->shm_path, "/ust",
+                       sizeof(lus->shm_path) - strlen(lus->shm_path) - 1);
+       }
        /* Copy session output to the newly created UST session */
        ret = copy_session_consumer(domain->type, session);
        if (ret != LTTNG_OK) {
@@ -2165,7 +2873,7 @@ static int create_kernel_session(struct ltt_session *session)
                                session->kernel_session->consumer->dst.trace_path,
                                S_IRWXU | S_IRWXG, session->uid, session->gid);
                if (ret < 0) {
-                       if (ret != -EEXIST) {
+                       if (errno != EEXIST) {
                                ERR("Trace directory creation error");
                                goto error;
                        }
@@ -2174,6 +2882,8 @@ static int create_kernel_session(struct ltt_session *session)
 
        session->kernel_session->uid = session->uid;
        session->kernel_session->gid = session->gid;
+       session->kernel_session->output_traces = session->output_traces;
+       session->kernel_session->snapshot_mode = session->snapshot_mode;
 
        return LTTNG_OK;
 
@@ -2213,6 +2923,8 @@ static unsigned int lttng_sessions_count(uid_t uid, gid_t gid)
  * Return any error encountered or 0 for success.
  *
  * "sock" is only used for special-case var. len data.
+ *
+ * Should *NOT* be called with RCU read-side lock held.
  */
 static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                int *sock_error)
@@ -2227,12 +2939,20 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
 
        switch (cmd_ctx->lsm->cmd_type) {
        case LTTNG_CREATE_SESSION:
+       case LTTNG_CREATE_SESSION_SNAPSHOT:
+       case LTTNG_CREATE_SESSION_LIVE:
        case LTTNG_DESTROY_SESSION:
        case LTTNG_LIST_SESSIONS:
        case LTTNG_LIST_DOMAINS:
        case LTTNG_START_TRACE:
        case LTTNG_STOP_TRACE:
        case LTTNG_DATA_PENDING:
+       case LTTNG_SNAPSHOT_ADD_OUTPUT:
+       case LTTNG_SNAPSHOT_DEL_OUTPUT:
+       case LTTNG_SNAPSHOT_LIST_OUTPUT:
+       case LTTNG_SNAPSHOT_RECORD:
+       case LTTNG_SAVE_SESSION:
+       case LTTNG_SET_SESSION_SHM_PATH:
                need_domain = 0;
                break;
        default:
@@ -2272,6 +2992,8 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_LIST_DOMAINS:
        case LTTNG_LIST_CHANNELS:
        case LTTNG_LIST_EVENTS:
+       case LTTNG_LIST_SYSCALLS:
+       case LTTNG_LIST_TRACKER_PIDS:
                break;
        default:
                /* Setup lttng message with no payload */
@@ -2285,10 +3007,14 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        /* Commands that DO NOT need a session. */
        switch (cmd_ctx->lsm->cmd_type) {
        case LTTNG_CREATE_SESSION:
+       case LTTNG_CREATE_SESSION_SNAPSHOT:
+       case LTTNG_CREATE_SESSION_LIVE:
        case LTTNG_CALIBRATE:
        case LTTNG_LIST_SESSIONS:
        case LTTNG_LIST_TRACEPOINTS:
+       case LTTNG_LIST_SYSCALLS:
        case LTTNG_LIST_TRACEPOINT_FIELDS:
+       case LTTNG_SAVE_SESSION:
                need_tracing_session = 0;
                break;
        default:
@@ -2301,12 +3027,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                session_lock_list();
                cmd_ctx->session = session_find_by_name(cmd_ctx->lsm->session.name);
                if (cmd_ctx->session == NULL) {
-                       if (cmd_ctx->lsm->session.name != NULL) {
-                               ret = LTTNG_ERR_SESS_NOT_FOUND;
-                       } else {
-                               /* If no session name specified */
-                               ret = LTTNG_ERR_SELECT_SESS;
-                       }
+                       ret = LTTNG_ERR_SESS_NOT_FOUND;
                        goto error;
                } else {
                        /* Acquire lock for the session */
@@ -2315,6 +3036,39 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                break;
        }
 
+       /*
+        * Commands that need a valid session but should NOT create one if none
+        * exists. Instead of creating one and destroying it when the command is
+        * handled, process that right before so we save some round trip in useless
+        * code path.
+        */
+       switch (cmd_ctx->lsm->cmd_type) {
+       case LTTNG_DISABLE_CHANNEL:
+       case LTTNG_DISABLE_EVENT:
+               switch (cmd_ctx->lsm->domain.type) {
+               case LTTNG_DOMAIN_KERNEL:
+                       if (!cmd_ctx->session->kernel_session) {
+                               ret = LTTNG_ERR_NO_CHANNEL;
+                               goto error;
+                       }
+                       break;
+               case LTTNG_DOMAIN_JUL:
+               case LTTNG_DOMAIN_LOG4J:
+               case LTTNG_DOMAIN_PYTHON:
+               case LTTNG_DOMAIN_UST:
+                       if (!cmd_ctx->session->ust_session) {
+                               ret = LTTNG_ERR_NO_CHANNEL;
+                               goto error;
+                       }
+                       break;
+               default:
+                       ret = LTTNG_ERR_UNKNOWN_DOMAIN;
+                       goto error;
+               }
+       default:
+               break;
+       }
+
        if (!need_domain) {
                goto skip_domain;
        }
@@ -2357,8 +3111,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                        /* Start the kernel consumer daemon */
                        pthread_mutex_lock(&kconsumer_data.pid_mutex);
                        if (kconsumer_data.pid == 0 &&
-                                       cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER &&
-                                       cmd_ctx->session->start_consumer) {
+                                       cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
                                pthread_mutex_unlock(&kconsumer_data.pid_mutex);
                                ret = start_consumerd(&kconsumer_data);
                                if (ret < 0) {
@@ -2382,8 +3135,15 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                }
 
                break;
+       case LTTNG_DOMAIN_JUL:
+       case LTTNG_DOMAIN_LOG4J:
+       case LTTNG_DOMAIN_PYTHON:
        case LTTNG_DOMAIN_UST:
        {
+               if (!ust_app_supported()) {
+                       ret = LTTNG_ERR_NO_UST;
+                       goto error;
+               }
                /* Consumer is in an ERROR state. Report back to client */
                if (uatomic_read(&ust_consumerd_state) == CONSUMER_ERROR) {
                        ret = LTTNG_ERR_NO_USTCONSUMERD;
@@ -2405,8 +3165,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                        pthread_mutex_lock(&ustconsumer64_data.pid_mutex);
                        if (consumerd64_bin[0] != '\0' &&
                                        ustconsumer64_data.pid == 0 &&
-                                       cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER &&
-                                       cmd_ctx->session->start_consumer) {
+                                       cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
                                pthread_mutex_unlock(&ustconsumer64_data.pid_mutex);
                                ret = start_consumerd(&ustconsumer64_data);
                                if (ret < 0) {
@@ -2432,10 +3191,10 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                        }
 
                        /* 32-bit */
+                       pthread_mutex_lock(&ustconsumer32_data.pid_mutex);
                        if (consumerd32_bin[0] != '\0' &&
                                        ustconsumer32_data.pid == 0 &&
-                                       cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER &&
-                                       cmd_ctx->session->start_consumer) {
+                                       cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
                                pthread_mutex_unlock(&ustconsumer32_data.pid_mutex);
                                ret = start_consumerd(&ustconsumer32_data);
                                if (ret < 0) {
@@ -2471,6 +3230,9 @@ skip_domain:
        if (cmd_ctx->lsm->cmd_type == LTTNG_START_TRACE ||
                        cmd_ctx->lsm->cmd_type == LTTNG_STOP_TRACE) {
                switch (cmd_ctx->lsm->domain.type) {
+               case LTTNG_DOMAIN_JUL:
+               case LTTNG_DOMAIN_LOG4J:
+               case LTTNG_DOMAIN_PYTHON:
                case LTTNG_DOMAIN_UST:
                        if (uatomic_read(&ust_consumerd_state) != CONSUMER_STARTED) {
                                ret = LTTNG_ERR_NO_USTCONSUMERD;
@@ -2499,6 +3261,21 @@ skip_domain:
                }
        }
 
+       /*
+        * Send relayd information to consumer as soon as we have a domain and a
+        * session defined.
+        */
+       if (cmd_ctx->session && need_domain) {
+               /*
+                * Setup relayd if not done yet. If the relayd information was already
+                * sent to the consumer, this call will gracefully return.
+                */
+               ret = cmd_setup_relayd(cmd_ctx->session);
+               if (ret != LTTNG_OK) {
+                       goto error;
+               }
+       }
+
        /* Process by command type */
        switch (cmd_ctx->lsm->cmd_type) {
        case LTTNG_ADD_CONTEXT:
@@ -2516,68 +3293,167 @@ skip_domain:
        }
        case LTTNG_DISABLE_EVENT:
        {
+
+               /*
+                * FIXME: handle filter; for now we just receive the filter's
+                * bytecode along with the filter expression which are sent by
+                * liblttng-ctl and discard them.
+                *
+                * This fixes an issue where the client may block while sending
+                * the filter payload and encounter an error because the session
+                * daemon closes the socket without ever handling this data.
+                */
+               size_t count = cmd_ctx->lsm->u.disable.expression_len +
+                       cmd_ctx->lsm->u.disable.bytecode_len;
+
+               if (count) {
+                       char data[LTTNG_FILTER_MAX_LEN];
+
+                       DBG("Discarding disable event command payload of size %zu", count);
+                       while (count) {
+                               ret = lttcomm_recv_unix_sock(sock, data,
+                                       count > sizeof(data) ? sizeof(data) : count);
+                               if (ret < 0) {
+                                       goto error;
+                               }
+
+                               count -= (size_t) ret;
+                       }
+               }
+               /* FIXME: passing packed structure to non-packed pointer */
                ret = cmd_disable_event(cmd_ctx->session, cmd_ctx->lsm->domain.type,
                                cmd_ctx->lsm->u.disable.channel_name,
-                               cmd_ctx->lsm->u.disable.name);
+                               &cmd_ctx->lsm->u.disable.event);
                break;
        }
-       case LTTNG_DISABLE_ALL_EVENT:
+       case LTTNG_ENABLE_CHANNEL:
        {
-               DBG("Disabling all events");
-
-               ret = cmd_disable_event_all(cmd_ctx->session, cmd_ctx->lsm->domain.type,
-                               cmd_ctx->lsm->u.disable.channel_name);
+               ret = cmd_enable_channel(cmd_ctx->session, &cmd_ctx->lsm->domain,
+                               &cmd_ctx->lsm->u.channel.chan, kernel_poll_pipe[1]);
                break;
        }
-       case LTTNG_DISABLE_CONSUMER:
+       case LTTNG_TRACK_PID:
        {
-               ret = cmd_disable_consumer(cmd_ctx->lsm->domain.type, cmd_ctx->session);
+               ret = cmd_track_pid(cmd_ctx->session,
+                               cmd_ctx->lsm->domain.type,
+                               cmd_ctx->lsm->u.pid_tracker.pid);
                break;
        }
-       case LTTNG_ENABLE_CHANNEL:
+       case LTTNG_UNTRACK_PID:
        {
-               ret = cmd_enable_channel(cmd_ctx->session, cmd_ctx->lsm->domain.type,
-                               &cmd_ctx->lsm->u.channel.chan, kernel_poll_pipe[1]);
+               ret = cmd_untrack_pid(cmd_ctx->session,
+                               cmd_ctx->lsm->domain.type,
+                               cmd_ctx->lsm->u.pid_tracker.pid);
                break;
        }
-       case LTTNG_ENABLE_CONSUMER:
+       case LTTNG_ENABLE_EVENT:
        {
-               /*
-                * XXX: 0 means that this URI should be applied on the session. Should
-                * be a DOMAIN enuam.
-                */
-               ret = cmd_enable_consumer(cmd_ctx->lsm->domain.type, cmd_ctx->session);
-               if (ret != LTTNG_OK) {
-                       goto error;
+               struct lttng_event_exclusion *exclusion = NULL;
+               struct lttng_filter_bytecode *bytecode = NULL;
+               char *filter_expression = NULL;
+
+               /* Handle exclusion events and receive it from the client. */
+               if (cmd_ctx->lsm->u.enable.exclusion_count > 0) {
+                       size_t count = cmd_ctx->lsm->u.enable.exclusion_count;
+
+                       exclusion = zmalloc(sizeof(struct lttng_event_exclusion) +
+                                       (count * LTTNG_SYMBOL_NAME_LEN));
+                       if (!exclusion) {
+                               ret = LTTNG_ERR_EXCLUSION_NOMEM;
+                               goto error;
+                       }
+
+                       DBG("Receiving var len exclusion event list from client ...");
+                       exclusion->count = count;
+                       ret = lttcomm_recv_unix_sock(sock, exclusion->names,
+                                       count * LTTNG_SYMBOL_NAME_LEN);
+                       if (ret <= 0) {
+                               DBG("Nothing recv() from client var len data... continuing");
+                               *sock_error = 1;
+                               free(exclusion);
+                               ret = LTTNG_ERR_EXCLUSION_INVAL;
+                               goto error;
+                       }
                }
 
-               if (cmd_ctx->lsm->domain.type == 0) {
-                       /* Add the URI for the UST session if a consumer is present. */
-                       if (cmd_ctx->session->ust_session &&
-                                       cmd_ctx->session->ust_session->consumer) {
-                               ret = cmd_enable_consumer(LTTNG_DOMAIN_UST, cmd_ctx->session);
-                       } else if (cmd_ctx->session->kernel_session &&
-                                       cmd_ctx->session->kernel_session->consumer) {
-                               ret = cmd_enable_consumer(LTTNG_DOMAIN_KERNEL,
-                                               cmd_ctx->session);
+               /* Get filter expression from client. */
+               if (cmd_ctx->lsm->u.enable.expression_len > 0) {
+                       size_t expression_len =
+                               cmd_ctx->lsm->u.enable.expression_len;
+
+                       if (expression_len > LTTNG_FILTER_MAX_LEN) {
+                               ret = LTTNG_ERR_FILTER_INVAL;
+                               free(exclusion);
+                               goto error;
+                       }
+
+                       filter_expression = zmalloc(expression_len);
+                       if (!filter_expression) {
+                               free(exclusion);
+                               ret = LTTNG_ERR_FILTER_NOMEM;
+                               goto error;
+                       }
+
+                       /* Receive var. len. data */
+                       DBG("Receiving var len filter's expression from client ...");
+                       ret = lttcomm_recv_unix_sock(sock, filter_expression,
+                               expression_len);
+                       if (ret <= 0) {
+                               DBG("Nothing recv() from client car len data... continuing");
+                               *sock_error = 1;
+                               free(filter_expression);
+                               free(exclusion);
+                               ret = LTTNG_ERR_FILTER_INVAL;
+                               goto error;
                        }
                }
-               break;
-       }
-       case LTTNG_ENABLE_EVENT:
-       {
-               ret = cmd_enable_event(cmd_ctx->session, cmd_ctx->lsm->domain.type,
-                               cmd_ctx->lsm->u.enable.channel_name,
-                               &cmd_ctx->lsm->u.enable.event, NULL, kernel_poll_pipe[1]);
-               break;
-       }
-       case LTTNG_ENABLE_ALL_EVENT:
-       {
-               DBG("Enabling all events");
 
-               ret = cmd_enable_event_all(cmd_ctx->session, cmd_ctx->lsm->domain.type,
+               /* Handle filter and get bytecode from client. */
+               if (cmd_ctx->lsm->u.enable.bytecode_len > 0) {
+                       size_t bytecode_len = cmd_ctx->lsm->u.enable.bytecode_len;
+
+                       if (bytecode_len > LTTNG_FILTER_MAX_LEN) {
+                               ret = LTTNG_ERR_FILTER_INVAL;
+                               free(filter_expression);
+                               free(exclusion);
+                               goto error;
+                       }
+
+                       bytecode = zmalloc(bytecode_len);
+                       if (!bytecode) {
+                               free(filter_expression);
+                               free(exclusion);
+                               ret = LTTNG_ERR_FILTER_NOMEM;
+                               goto error;
+                       }
+
+                       /* Receive var. len. data */
+                       DBG("Receiving var len filter's bytecode from client ...");
+                       ret = lttcomm_recv_unix_sock(sock, bytecode, bytecode_len);
+                       if (ret <= 0) {
+                               DBG("Nothing recv() from client car len data... continuing");
+                               *sock_error = 1;
+                               free(filter_expression);
+                               free(bytecode);
+                               free(exclusion);
+                               ret = LTTNG_ERR_FILTER_INVAL;
+                               goto error;
+                       }
+
+                       if ((bytecode->len + sizeof(*bytecode)) != bytecode_len) {
+                               free(filter_expression);
+                               free(bytecode);
+                               free(exclusion);
+                               ret = LTTNG_ERR_FILTER_INVAL;
+                               goto error;
+                       }
+               }
+
+               ret = cmd_enable_event(cmd_ctx->session, &cmd_ctx->lsm->domain,
                                cmd_ctx->lsm->u.enable.channel_name,
-                               cmd_ctx->lsm->u.enable.event.type, NULL, kernel_poll_pipe[1]);
+                               &cmd_ctx->lsm->u.enable.event,
+                               filter_expression, bytecode, exclusion,
+                               kernel_poll_pipe[1]);
                break;
        }
        case LTTNG_LIST_TRACEPOINTS:
@@ -2585,7 +3461,9 @@ skip_domain:
                struct lttng_event *events;
                ssize_t nb_events;
 
+               session_lock_list();
                nb_events = cmd_list_tracepoints(cmd_ctx->lsm->domain.type, &events);
+               session_unlock_list();
                if (nb_events < 0) {
                        /* Return value is a negative lttng_error_code. */
                        ret = -nb_events;
@@ -2616,8 +3494,10 @@ skip_domain:
                struct lttng_event_field *fields;
                ssize_t nb_fields;
 
+               session_lock_list();
                nb_fields = cmd_list_tracepoint_fields(cmd_ctx->lsm->domain.type,
                                &fields);
+               session_unlock_list();
                if (nb_fields < 0) {
                        /* Return value is a negative lttng_error_code. */
                        ret = -nb_fields;
@@ -2644,6 +3524,69 @@ skip_domain:
                ret = LTTNG_OK;
                break;
        }
+       case LTTNG_LIST_SYSCALLS:
+       {
+               struct lttng_event *events;
+               ssize_t nb_events;
+
+               nb_events = cmd_list_syscalls(&events);
+               if (nb_events < 0) {
+                       /* Return value is a negative lttng_error_code. */
+                       ret = -nb_events;
+                       goto error;
+               }
+
+               /*
+                * Setup lttng message with payload size set to the event list size in
+                * bytes and then copy list into the llm payload.
+                */
+               ret = setup_lttng_msg(cmd_ctx, sizeof(struct lttng_event) * nb_events);
+               if (ret < 0) {
+                       free(events);
+                       goto setup_error;
+               }
+
+               /* Copy event list into message payload */
+               memcpy(cmd_ctx->llm->payload, events,
+                               sizeof(struct lttng_event) * nb_events);
+
+               free(events);
+
+               ret = LTTNG_OK;
+               break;
+       }
+       case LTTNG_LIST_TRACKER_PIDS:
+       {
+               int32_t *pids = NULL;
+               ssize_t nr_pids;
+
+               nr_pids = cmd_list_tracker_pids(cmd_ctx->session,
+                               cmd_ctx->lsm->domain.type, &pids);
+               if (nr_pids < 0) {
+                       /* Return value is a negative lttng_error_code. */
+                       ret = -nr_pids;
+                       goto error;
+               }
+
+               /*
+                * Setup lttng message with payload size set to the event list size in
+                * bytes and then copy list into the llm payload.
+                */
+               ret = setup_lttng_msg(cmd_ctx, sizeof(int32_t) * nr_pids);
+               if (ret < 0) {
+                       free(pids);
+                       goto setup_error;
+               }
+
+               /* Copy event list into message payload */
+               memcpy(cmd_ctx->llm->payload, pids,
+                               sizeof(int) * nr_pids);
+
+               free(pids);
+
+               ret = LTTNG_OK;
+               break;
+       }
        case LTTNG_SET_CONSUMER_URI:
        {
                size_t nb_uri, len;
@@ -2674,31 +3617,12 @@ skip_domain:
                        goto error;
                }
 
-               ret = cmd_set_consumer_uri(cmd_ctx->lsm->domain.type, cmd_ctx->session,
-                               nb_uri, uris);
+               ret = cmd_set_consumer_uri(cmd_ctx->session, nb_uri, uris);
+               free(uris);
                if (ret != LTTNG_OK) {
-                       free(uris);
                        goto error;
                }
 
-               /*
-                * XXX: 0 means that this URI should be applied on the session. Should
-                * be a DOMAIN enuam.
-                */
-               if (cmd_ctx->lsm->domain.type == 0) {
-                       /* Add the URI for the UST session if a consumer is present. */
-                       if (cmd_ctx->session->ust_session &&
-                                       cmd_ctx->session->ust_session->consumer) {
-                               ret = cmd_set_consumer_uri(LTTNG_DOMAIN_UST, cmd_ctx->session,
-                                               nb_uri, uris);
-                       } else if (cmd_ctx->session->kernel_session &&
-                                       cmd_ctx->session->kernel_session->consumer) {
-                               ret = cmd_set_consumer_uri(LTTNG_DOMAIN_KERNEL,
-                                               cmd_ctx->session, nb_uri, uris);
-                       }
-               }
-
-               free(uris);
 
                break;
        }
@@ -2747,7 +3671,7 @@ skip_domain:
                }
 
                ret = cmd_create_session_uri(cmd_ctx->lsm->session.name, uris, nb_uri,
-                       &cmd_ctx->creds);
+                       &cmd_ctx->creds, 0);
 
                free(uris);
 
@@ -2764,7 +3688,7 @@ skip_domain:
        case LTTNG_LIST_DOMAINS:
        {
                ssize_t nb_dom;
-               struct lttng_domain *domains;
+               struct lttng_domain *domains = NULL;
 
                nb_dom = cmd_list_domains(cmd_ctx->session, &domains);
                if (nb_dom < 0) {
@@ -2775,6 +3699,7 @@ skip_domain:
 
                ret = setup_lttng_msg(cmd_ctx, nb_dom * sizeof(struct lttng_domain));
                if (ret < 0) {
+                       free(domains);
                        goto setup_error;
                }
 
@@ -2790,7 +3715,7 @@ skip_domain:
        case LTTNG_LIST_CHANNELS:
        {
                int nb_chan;
-               struct lttng_channel *channels;
+               struct lttng_channel *channels = NULL;
 
                nb_chan = cmd_list_channels(cmd_ctx->lsm->domain.type,
                                cmd_ctx->session, &channels);
@@ -2802,6 +3727,7 @@ skip_domain:
 
                ret = setup_lttng_msg(cmd_ctx, nb_chan * sizeof(struct lttng_channel));
                if (ret < 0) {
+                       free(channels);
                        goto setup_error;
                }
 
@@ -2829,6 +3755,7 @@ skip_domain:
 
                ret = setup_lttng_msg(cmd_ctx, nb_event * sizeof(struct lttng_event));
                if (ret < 0) {
+                       free(events);
                        goto setup_error;
                }
 
@@ -2889,90 +3816,232 @@ skip_domain:
                                cmd_ctx->lsm->u.reg.path, cdata);
                break;
        }
-       case LTTNG_ENABLE_EVENT_WITH_FILTER:
+       case LTTNG_DATA_PENDING:
        {
-               struct lttng_filter_bytecode *bytecode;
+               int pending_ret;
 
-               if (cmd_ctx->lsm->u.enable.bytecode_len > LTTNG_FILTER_MAX_LEN) {
-                       ret = LTTNG_ERR_FILTER_INVAL;
-                       goto error;
-               }
-               if (cmd_ctx->lsm->u.enable.bytecode_len == 0) {
-                       ret = LTTNG_ERR_FILTER_INVAL;
-                       goto error;
+               /* 1 byte to return whether or not data is pending */
+               ret = setup_lttng_msg(cmd_ctx, 1);
+               if (ret < 0) {
+                       goto setup_error;
                }
-               bytecode = zmalloc(cmd_ctx->lsm->u.enable.bytecode_len);
-               if (!bytecode) {
-                       ret = LTTNG_ERR_FILTER_NOMEM;
-                       goto error;
+
+               pending_ret = cmd_data_pending(cmd_ctx->session);
+               /*
+                * FIXME
+                *
+                * This function may returns 0 or 1 to indicate whether or not
+                * there is data pending. In case of error, it should return an
+                * LTTNG_ERR code. However, some code paths may still return
+                * a nondescript error code, which we handle by returning an
+                * "unknown" error.
+                */
+               if (pending_ret == 0 || pending_ret == 1) {
+                       ret = LTTNG_OK;
+               } else if (pending_ret < 0) {
+                       ret = LTTNG_ERR_UNK;
+                       goto setup_error;
+               } else {
+                       ret = pending_ret;
+                       goto setup_error;
                }
-               /* Receive var. len. data */
-               DBG("Receiving var len data from client ...");
-               ret = lttcomm_recv_unix_sock(sock, bytecode,
-                               cmd_ctx->lsm->u.enable.bytecode_len);
-               if (ret <= 0) {
-                       DBG("Nothing recv() from client var len data... continuing");
-                       *sock_error = 1;
-                       ret = LTTNG_ERR_FILTER_INVAL;
+
+               *cmd_ctx->llm->payload = (uint8_t) pending_ret;
+               break;
+       }
+       case LTTNG_SNAPSHOT_ADD_OUTPUT:
+       {
+               struct lttcomm_lttng_output_id reply;
+
+               ret = cmd_snapshot_add_output(cmd_ctx->session,
+                               &cmd_ctx->lsm->u.snapshot_output.output, &reply.id);
+               if (ret != LTTNG_OK) {
                        goto error;
                }
 
-               if (bytecode->len + sizeof(*bytecode)
-                               != cmd_ctx->lsm->u.enable.bytecode_len) {
-                       free(bytecode);
-                       ret = LTTNG_ERR_FILTER_INVAL;
-                       goto error;
+               ret = setup_lttng_msg(cmd_ctx, sizeof(reply));
+               if (ret < 0) {
+                       goto setup_error;
                }
 
-               ret = cmd_enable_event(cmd_ctx->session, cmd_ctx->lsm->domain.type,
-                               cmd_ctx->lsm->u.enable.channel_name,
-                               &cmd_ctx->lsm->u.enable.event, bytecode, kernel_poll_pipe[1]);
+               /* Copy output list into message payload */
+               memcpy(cmd_ctx->llm->payload, &reply, sizeof(reply));
+               ret = LTTNG_OK;
                break;
        }
-       case LTTNG_DATA_PENDING:
+       case LTTNG_SNAPSHOT_DEL_OUTPUT:
        {
-               ret = cmd_data_pending(cmd_ctx->session);
-               break;
-       }
-       default:
-               ret = LTTNG_ERR_UND;
+               ret = cmd_snapshot_del_output(cmd_ctx->session,
+                               &cmd_ctx->lsm->u.snapshot_output.output);
                break;
        }
+       case LTTNG_SNAPSHOT_LIST_OUTPUT:
+       {
+               ssize_t nb_output;
+               struct lttng_snapshot_output *outputs = NULL;
 
-error:
-       if (cmd_ctx->llm == NULL) {
-               DBG("Missing llm structure. Allocating one.");
-               if (setup_lttng_msg(cmd_ctx, 0) < 0) {
+               nb_output = cmd_snapshot_list_outputs(cmd_ctx->session, &outputs);
+               if (nb_output < 0) {
+                       ret = -nb_output;
+                       goto error;
+               }
+
+               ret = setup_lttng_msg(cmd_ctx,
+                               nb_output * sizeof(struct lttng_snapshot_output));
+               if (ret < 0) {
+                       free(outputs);
                        goto setup_error;
                }
+
+               if (outputs) {
+                       /* Copy output list into message payload */
+                       memcpy(cmd_ctx->llm->payload, outputs,
+                                       nb_output * sizeof(struct lttng_snapshot_output));
+                       free(outputs);
+               }
+
+               ret = LTTNG_OK;
+               break;
        }
-       /* Set return code */
-       cmd_ctx->llm->ret_code = ret;
-setup_error:
-       if (cmd_ctx->session) {
-               session_unlock(cmd_ctx->session);
-       }
-       if (need_tracing_session) {
-               session_unlock_list();
+       case LTTNG_SNAPSHOT_RECORD:
+       {
+               ret = cmd_snapshot_record(cmd_ctx->session,
+                               &cmd_ctx->lsm->u.snapshot_record.output,
+                               cmd_ctx->lsm->u.snapshot_record.wait);
+               break;
        }
-init_setup_error:
-       return ret;
-}
-
-/*
- * Thread managing health check socket.
- */
-static void *thread_manage_health(void *data)
-{
-       int sock = -1, new_sock = -1, ret, i, pollfd, err = -1;
-       uint32_t revents, nb_fd;
-       struct lttng_poll_event events;
-       struct lttcomm_health_msg msg;
-       struct lttcomm_health_data reply;
+       case LTTNG_CREATE_SESSION_SNAPSHOT:
+       {
+               size_t nb_uri, len;
+               struct lttng_uri *uris = NULL;
 
-       DBG("[thread] Manage health check started");
+               nb_uri = cmd_ctx->lsm->u.uri.size;
+               len = nb_uri * sizeof(struct lttng_uri);
 
-       rcu_register_thread();
+               if (nb_uri > 0) {
+                       uris = zmalloc(len);
+                       if (uris == NULL) {
+                               ret = LTTNG_ERR_FATAL;
+                               goto error;
+                       }
+
+                       /* Receive variable len data */
+                       DBG("Waiting for %zu URIs from client ...", nb_uri);
+                       ret = lttcomm_recv_unix_sock(sock, uris, len);
+                       if (ret <= 0) {
+                               DBG("No URIs received from client... continuing");
+                               *sock_error = 1;
+                               ret = LTTNG_ERR_SESSION_FAIL;
+                               free(uris);
+                               goto error;
+                       }
+
+                       if (nb_uri == 1 && uris[0].dtype != LTTNG_DST_PATH) {
+                               DBG("Creating session with ONE network URI is a bad call");
+                               ret = LTTNG_ERR_SESSION_FAIL;
+                               free(uris);
+                               goto error;
+                       }
+               }
+
+               ret = cmd_create_session_snapshot(cmd_ctx->lsm->session.name, uris,
+                               nb_uri, &cmd_ctx->creds);
+               free(uris);
+               break;
+       }
+       case LTTNG_CREATE_SESSION_LIVE:
+       {
+               size_t nb_uri, len;
+               struct lttng_uri *uris = NULL;
+
+               nb_uri = cmd_ctx->lsm->u.uri.size;
+               len = nb_uri * sizeof(struct lttng_uri);
+
+               if (nb_uri > 0) {
+                       uris = zmalloc(len);
+                       if (uris == NULL) {
+                               ret = LTTNG_ERR_FATAL;
+                               goto error;
+                       }
+
+                       /* Receive variable len data */
+                       DBG("Waiting for %zu URIs from client ...", nb_uri);
+                       ret = lttcomm_recv_unix_sock(sock, uris, len);
+                       if (ret <= 0) {
+                               DBG("No URIs received from client... continuing");
+                               *sock_error = 1;
+                               ret = LTTNG_ERR_SESSION_FAIL;
+                               free(uris);
+                               goto error;
+                       }
+
+                       if (nb_uri == 1 && uris[0].dtype != LTTNG_DST_PATH) {
+                               DBG("Creating session with ONE network URI is a bad call");
+                               ret = LTTNG_ERR_SESSION_FAIL;
+                               free(uris);
+                               goto error;
+                       }
+               }
+
+               ret = cmd_create_session_uri(cmd_ctx->lsm->session.name, uris,
+                               nb_uri, &cmd_ctx->creds, cmd_ctx->lsm->u.session_live.timer_interval);
+               free(uris);
+               break;
+       }
+       case LTTNG_SAVE_SESSION:
+       {
+               ret = cmd_save_sessions(&cmd_ctx->lsm->u.save_session.attr,
+                       &cmd_ctx->creds);
+               break;
+       }
+       case LTTNG_SET_SESSION_SHM_PATH:
+       {
+               ret = cmd_set_session_shm_path(cmd_ctx->session,
+                               cmd_ctx->lsm->u.set_shm_path.shm_path);
+               break;
+       }
+       default:
+               ret = LTTNG_ERR_UND;
+               break;
+       }
+
+error:
+       if (cmd_ctx->llm == NULL) {
+               DBG("Missing llm structure. Allocating one.");
+               if (setup_lttng_msg(cmd_ctx, 0) < 0) {
+                       goto setup_error;
+               }
+       }
+       /* Set return code */
+       cmd_ctx->llm->ret_code = ret;
+setup_error:
+       if (cmd_ctx->session) {
+               session_unlock(cmd_ctx->session);
+       }
+       if (need_tracing_session) {
+               session_unlock_list();
+       }
+init_setup_error:
+       return ret;
+}
+
+/*
+ * Thread managing health check socket.
+ */
+static void *thread_manage_health(void *data)
+{
+       int sock = -1, new_sock = -1, ret, i, pollfd, err = -1;
+       uint32_t revents, nb_fd;
+       struct lttng_poll_event events;
+       struct health_comm_msg msg;
+       struct health_comm_reply reply;
+
+       DBG("[thread] Manage health check started");
+
+       rcu_register_thread();
+
+       /* We might hit an error path before this is created. */
+       lttng_poll_init(&events);
 
        /* Create unix socket */
        sock = lttcomm_create_unix_sock(health_unix_sock_path);
@@ -2982,6 +4051,27 @@ static void *thread_manage_health(void *data)
                goto error;
        }
 
+       if (is_root) {
+               /* lttng health client socket path permissions */
+               ret = chown(health_unix_sock_path, 0,
+                               utils_get_group_id(tracing_group_name));
+               if (ret < 0) {
+                       ERR("Unable to set group on %s", health_unix_sock_path);
+                       PERROR("chown");
+                       ret = -1;
+                       goto error;
+               }
+
+               ret = chmod(health_unix_sock_path,
+                               S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+               if (ret < 0) {
+                       ERR("Unable to set permissions on %s", health_unix_sock_path);
+                       PERROR("chmod");
+                       ret = -1;
+                       goto error;
+               }
+       }
+
        /*
         * Set the CLOEXEC flag. Return code is useless because either way, the
         * show must go on.
@@ -2997,7 +4087,7 @@ static void *thread_manage_health(void *data)
         * Pass 2 as size here for the thread quit pipe and client_sock. Nothing
         * more will be added to this poll set.
         */
-       ret = create_thread_poll_set(&events, 2);
+       ret = sessiond_set_thread_pollset(&events, 2);
        if (ret < 0) {
                goto error;
        }
@@ -3008,6 +4098,8 @@ static void *thread_manage_health(void *data)
                goto error;
        }
 
+       sessiond_notify_ready();
+
        while (1) {
                DBG("Health check ready");
 
@@ -3031,8 +4123,13 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
-                       ret = check_thread_quit_pipe(pollfd, revents);
+                       ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
                                err = 0;
                                goto exit;
@@ -3072,46 +4169,18 @@ restart:
 
                rcu_thread_online();
 
-               switch (msg.component) {
-               case LTTNG_HEALTH_CMD:
-                       reply.ret_code = health_check_state(HEALTH_TYPE_CMD);
-                       break;
-               case LTTNG_HEALTH_APP_MANAGE:
-                       reply.ret_code = health_check_state(HEALTH_TYPE_APP_MANAGE);
-                       break;
-               case LTTNG_HEALTH_APP_REG:
-                       reply.ret_code = health_check_state(HEALTH_TYPE_APP_REG);
-                       break;
-               case LTTNG_HEALTH_KERNEL:
-                       reply.ret_code = health_check_state(HEALTH_TYPE_KERNEL);
-                       break;
-               case LTTNG_HEALTH_CONSUMER:
-                       reply.ret_code = check_consumer_health();
-                       break;
-               case LTTNG_HEALTH_ALL:
-                       reply.ret_code =
-                               health_check_state(HEALTH_TYPE_APP_MANAGE) &&
-                               health_check_state(HEALTH_TYPE_APP_REG) &&
-                               health_check_state(HEALTH_TYPE_CMD) &&
-                               health_check_state(HEALTH_TYPE_KERNEL) &&
-                               check_consumer_health();
-                       break;
-               default:
-                       reply.ret_code = LTTNG_ERR_UND;
-                       break;
-               }
-
-               /*
-                * Flip ret value since 0 is a success and 1 indicates a bad health for
-                * the client where in the sessiond it is the opposite. Again, this is
-                * just to make things easier for us poor developer which enjoy a lot
-                * lazyness.
-                */
-               if (reply.ret_code == 0 || reply.ret_code == 1) {
-                       reply.ret_code = !reply.ret_code;
+               memset(&reply, 0, sizeof(reply));
+               for (i = 0; i < NR_HEALTH_SESSIOND_TYPES; i++) {
+                       /*
+                        * health_check_state returns 0 if health is
+                        * bad.
+                        */
+                       if (!health_check_state(health_sessiond, i)) {
+                               reply.ret_code |= 1ULL << i;
+                       }
                }
 
-               DBG2("Health check return value %d", reply.ret_code);
+               DBG2("Health check return value %" PRIx64, reply.ret_code);
 
                ret = send_unix_sock(new_sock, (void *) &reply, sizeof(reply));
                if (ret < 0) {
@@ -3139,12 +4208,6 @@ error:
                        PERROR("close");
                }
        }
-       if (new_sock >= 0) {
-               ret = close(new_sock);
-               if (ret) {
-                       PERROR("close");
-               }
-       }
 
        lttng_poll_clean(&events);
 
@@ -3168,13 +4231,9 @@ static void *thread_manage_clients(void *data)
 
        rcu_register_thread();
 
-       health_register(HEALTH_TYPE_CMD);
-
-       if (testpoint(thread_manage_clients)) {
-               goto error_testpoint;
-       }
+       health_register(health_sessiond, HEALTH_SESSIOND_TYPE_CMD);
 
-       health_code_update(&health_thread_cmd);
+       health_code_update();
 
        ret = lttcomm_listen_unix_sock(client_sock);
        if (ret < 0) {
@@ -3185,7 +4244,7 @@ static void *thread_manage_clients(void *data)
         * Pass 2 as size here for the thread quit pipe and client_sock. Nothing
         * more will be added to this poll set.
         */
-       ret = create_thread_poll_set(&events, 2);
+       ret = sessiond_set_thread_pollset(&events, 2);
        if (ret < 0) {
                goto error_create_poll;
        }
@@ -3196,27 +4255,32 @@ static void *thread_manage_clients(void *data)
                goto error;
        }
 
-       /*
-        * Notify parent pid that we are ready to accept command for client side.
-        */
-       if (opt_sig_parent) {
-               kill(ppid, SIGUSR1);
+       sessiond_notify_ready();
+       ret = sem_post(&load_info->message_thread_ready);
+       if (ret) {
+               PERROR("sem_post message_thread_ready");
+               goto error;
+       }
+
+       /* This testpoint is after we signal readiness to the parent. */
+       if (testpoint(sessiond_thread_manage_clients)) {
+               goto error;
        }
 
-       if (testpoint(thread_manage_clients_before_loop)) {
+       if (testpoint(sessiond_thread_manage_clients_before_loop)) {
                goto error;
        }
 
-       health_code_update(&health_thread_cmd);
+       health_code_update();
 
        while (1) {
                DBG("Accepting client command ...");
 
                /* Inifinite blocking call, waiting for transmission */
        restart:
-               health_poll_update(&health_thread_cmd);
+               health_poll_entry();
                ret = lttng_poll_wait(&events, -1);
-               health_poll_update(&health_thread_cmd);
+               health_poll_exit();
                if (ret < 0) {
                        /*
                         * Restart interrupted system call.
@@ -3234,10 +4298,15 @@ static void *thread_manage_clients(void *data)
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
-                       health_code_update(&health_thread_cmd);
+                       health_code_update();
+
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
 
                        /* Thread quit pipe has been closed. Killing thread. */
-                       ret = check_thread_quit_pipe(pollfd, revents);
+                       ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
                                err = 0;
                                goto exit;
@@ -3254,7 +4323,7 @@ static void *thread_manage_clients(void *data)
 
                DBG("Wait for client response");
 
-               health_code_update(&health_thread_cmd);
+               health_code_update();
 
                sock = lttcomm_accept_unix_sock(client_sock);
                if (sock < 0) {
@@ -3290,7 +4359,7 @@ static void *thread_manage_clients(void *data)
                cmd_ctx->llm = NULL;
                cmd_ctx->session = NULL;
 
-               health_code_update(&health_thread_cmd);
+               health_code_update();
 
                /*
                 * Data is received from the lttng client. The struct
@@ -3311,7 +4380,7 @@ static void *thread_manage_clients(void *data)
                        continue;
                }
 
-               health_code_update(&health_thread_cmd);
+               health_code_update();
 
                // TODO: Validate cmd_ctx including sanity check for
                // security purpose.
@@ -3326,13 +4395,11 @@ static void *thread_manage_clients(void *data)
                ret = process_client_msg(cmd_ctx, sock, &sock_error);
                rcu_thread_offline();
                if (ret < 0) {
-                       if (sock_error) {
-                               ret = close(sock);
-                               if (ret) {
-                                       PERROR("close");
-                               }
-                               sock = -1;
+                       ret = close(sock);
+                       if (ret) {
+                               PERROR("close");
                        }
+                       sock = -1;
                        /*
                         * TODO: Inform client somehow of the fatal error. At
                         * this point, ret < 0 means that a zmalloc failed
@@ -3344,11 +4411,12 @@ static void *thread_manage_clients(void *data)
                        continue;
                }
 
-               health_code_update(&health_thread_cmd);
+               health_code_update();
 
-               DBG("Sending response (size: %d, retcode: %s)",
+               DBG("Sending response (size: %d, retcode: %s (%d))",
                                cmd_ctx->lttng_msg_size,
-                               lttng_strerror(-cmd_ctx->llm->ret_code));
+                               lttng_strerror(-cmd_ctx->llm->ret_code),
+                               cmd_ctx->llm->ret_code);
                ret = send_unix_sock(sock, cmd_ctx->llm, cmd_ctx->lttng_msg_size);
                if (ret < 0) {
                        ERR("Failed to send data back to client");
@@ -3363,7 +4431,7 @@ static void *thread_manage_clients(void *data)
 
                clean_command_ctx(&cmd_ctx);
 
-               health_code_update(&health_thread_cmd);
+               health_code_update();
        }
 
 exit:
@@ -3380,7 +4448,6 @@ error:
 
 error_listen:
 error_create_poll:
-error_testpoint:
        unlink(client_unix_sock_path);
        if (client_sock >= 0) {
                ret = close(client_sock);
@@ -3390,15 +4457,37 @@ error_testpoint:
        }
 
        if (err) {
-               health_error(&health_thread_cmd);
+               health_error();
                ERR("Health error occurred in %s", __func__);
        }
 
-       health_unregister();
+       health_unregister(health_sessiond);
 
        DBG("Client thread dying");
 
        rcu_unregister_thread();
+
+       /*
+        * Since we are creating the consumer threads, we own them, so we need
+        * to join them before our thread exits.
+        */
+       ret = join_consumer_thread(&kconsumer_data);
+       if (ret) {
+               errno = ret;
+               PERROR("join_consumer");
+       }
+
+       ret = join_consumer_thread(&ustconsumer32_data);
+       if (ret) {
+               errno = ret;
+               PERROR("join_consumer ust32");
+       }
+
+       ret = join_consumer_thread(&ustconsumer64_data);
+       if (ret) {
+               errno = ret;
+               PERROR("join_consumer ust64");
+       }
        return NULL;
 }
 
@@ -3423,139 +4512,454 @@ static void usage(void)
        fprintf(stderr, "      --consumerd64-path PATH     Specify path for the 64-bit UST consumer daemon binary\n");
        fprintf(stderr, "      --consumerd64-libdir PATH   Specify path for the 64-bit UST consumer daemon libraries\n");
        fprintf(stderr, "  -d, --daemonize                    Start as a daemon.\n");
+       fprintf(stderr, "  -b, --background                   Start as a daemon, keeping console open.\n");
        fprintf(stderr, "  -g, --group NAME                   Specify the tracing group name. (default: tracing)\n");
        fprintf(stderr, "  -V, --version                      Show version number.\n");
-       fprintf(stderr, "  -S, --sig-parent                   Send SIGCHLD to parent pid to notify readiness.\n");
+       fprintf(stderr, "  -S, --sig-parent                   Send SIGUSR1 to parent pid to notify readiness.\n");
        fprintf(stderr, "  -q, --quiet                        No output at all.\n");
        fprintf(stderr, "  -v, --verbose                      Verbose mode. Activate DBG() macro.\n");
        fprintf(stderr, "  -p, --pidfile FILE                 Write a pid to FILE name overriding the default value.\n");
        fprintf(stderr, "      --verbose-consumer             Verbose mode for consumer. Activate DBG() macro.\n");
        fprintf(stderr, "      --no-kernel                    Disable kernel tracer\n");
+       fprintf(stderr, "      --agent-tcp-port               Agent registration TCP port\n");
+       fprintf(stderr, "  -f  --config PATH                  Load daemon configuration file\n");
+       fprintf(stderr, "  -l  --load PATH                    Load session configuration\n");
+       fprintf(stderr, "      --kmod-probes                  Specify kernel module probes to load\n");
+       fprintf(stderr, "      --extra-kmod-probes            Specify extra kernel module probes to load\n");
+}
+
+static int string_match(const char *str1, const char *str2)
+{
+       return (str1 && str2) && !strcmp(str1, str2);
 }
 
 /*
- * daemon argument parsing
+ * Take an option from the getopt output and set it in the right variable to be
+ * used later.
+ *
+ * Return 0 on success else a negative value.
  */
-static int parse_args(int argc, char **argv)
+static int set_option(int opt, const char *arg, const char *optname)
 {
-       int c;
-
-       static struct option long_options[] = {
-               { "client-sock", 1, 0, 'c' },
-               { "apps-sock", 1, 0, 'a' },
-               { "kconsumerd-cmd-sock", 1, 0, 'C' },
-               { "kconsumerd-err-sock", 1, 0, 'E' },
-               { "ustconsumerd32-cmd-sock", 1, 0, 'G' },
-               { "ustconsumerd32-err-sock", 1, 0, 'H' },
-               { "ustconsumerd64-cmd-sock", 1, 0, 'D' },
-               { "ustconsumerd64-err-sock", 1, 0, 'F' },
-               { "consumerd32-path", 1, 0, 'u' },
-               { "consumerd32-libdir", 1, 0, 'U' },
-               { "consumerd64-path", 1, 0, 't' },
-               { "consumerd64-libdir", 1, 0, 'T' },
-               { "daemonize", 0, 0, 'd' },
-               { "sig-parent", 0, 0, 'S' },
-               { "help", 0, 0, 'h' },
-               { "group", 1, 0, 'g' },
-               { "version", 0, 0, 'V' },
-               { "quiet", 0, 0, 'q' },
-               { "verbose", 0, 0, 'v' },
-               { "verbose-consumer", 0, 0, 'Z' },
-               { "no-kernel", 0, 0, 'N' },
-               { "pidfile", 1, 0, 'p' },
-               { NULL, 0, 0, 0 }
-       };
+       int ret = 0;
+
+       if (arg && arg[0] == '\0') {
+               /*
+                * This only happens if the value is read from daemon config
+                * file. This means the option requires an argument and the
+                * configuration file contains a line such as:
+                * my_option =
+                */
+               ret = -EINVAL;
+               goto end;
+       }
+
+       if (string_match(optname, "client-sock") || opt == 'c') {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-c, --client-sock");
+               } else {
+                       snprintf(client_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "apps-sock") || opt == 'a') {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-a, --apps-sock");
+               } else {
+                       snprintf(apps_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "daemonize") || opt == 'd') {
+               opt_daemon = 1;
+       } else if (string_match(optname, "background") || opt == 'b') {
+               opt_background = 1;
+       } else if (string_match(optname, "group") || opt == 'g') {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-g, --group");
+               } else {
+                       /*
+                        * If the override option is set, the pointer points to a
+                        * *non* const thus freeing it even though the variable type is
+                        * set to const.
+                        */
+                       if (tracing_group_name_override) {
+                               free((void *) tracing_group_name);
+                       }
+                       tracing_group_name = strdup(arg);
+                       if (!tracing_group_name) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+                       tracing_group_name_override = 1;
+               }
+       } else if (string_match(optname, "help") || opt == 'h') {
+               usage();
+               exit(EXIT_SUCCESS);
+       } else if (string_match(optname, "version") || opt == 'V') {
+               fprintf(stdout, "%s\n", VERSION);
+               exit(EXIT_SUCCESS);
+       } else if (string_match(optname, "sig-parent") || opt == 'S') {
+               opt_sig_parent = 1;
+       } else if (string_match(optname, "kconsumerd-err-sock")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--kconsumerd-err-sock");
+               } else {
+                       snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "kconsumerd-cmd-sock")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--kconsumerd-cmd-sock");
+               } else {
+                       snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "ustconsumerd64-err-sock")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd64-err-sock");
+               } else {
+                       snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "ustconsumerd64-cmd-sock")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd64-cmd-sock");
+               } else {
+                       snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "ustconsumerd32-err-sock")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd32-err-sock");
+               } else {
+                       snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "ustconsumerd32-cmd-sock")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd32-cmd-sock");
+               } else {
+                       snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
+               }
+       } else if (string_match(optname, "no-kernel")) {
+               opt_no_kernel = 1;
+       } else if (string_match(optname, "quiet") || opt == 'q') {
+               lttng_opt_quiet = 1;
+       } else if (string_match(optname, "verbose") || opt == 'v') {
+               /* Verbose level can increase using multiple -v */
+               if (arg) {
+                       /* Value obtained from config file */
+                       lttng_opt_verbose = config_parse_value(arg);
+               } else {
+                       /* -v used on command line */
+                       lttng_opt_verbose++;
+               }
+               /* Clamp value to [0, 3] */
+               lttng_opt_verbose = lttng_opt_verbose < 0 ? 0 :
+                       (lttng_opt_verbose <= 3 ? lttng_opt_verbose : 3);
+       } else if (string_match(optname, "verbose-consumer")) {
+               if (arg) {
+                       opt_verbose_consumer = config_parse_value(arg);
+               } else {
+                       opt_verbose_consumer += 1;
+               }
+       } else if (string_match(optname, "consumerd32-path")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd32-path");
+               } else {
+                       if (consumerd32_bin_override) {
+                               free((void *) consumerd32_bin);
+                       }
+                       consumerd32_bin = strdup(arg);
+                       if (!consumerd32_bin) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+                       consumerd32_bin_override = 1;
+               }
+       } else if (string_match(optname, "consumerd32-libdir")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd32-libdir");
+               } else {
+                       if (consumerd32_libdir_override) {
+                               free((void *) consumerd32_libdir);
+                       }
+                       consumerd32_libdir = strdup(arg);
+                       if (!consumerd32_libdir) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+                       consumerd32_libdir_override = 1;
+               }
+       } else if (string_match(optname, "consumerd64-path")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd64-path");
+               } else {
+                       if (consumerd64_bin_override) {
+                               free((void *) consumerd64_bin);
+                       }
+                       consumerd64_bin = strdup(arg);
+                       if (!consumerd64_bin) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+                       consumerd64_bin_override = 1;
+               }
+       } else if (string_match(optname, "consumerd64-libdir")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd64-libdir");
+               } else {
+                       if (consumerd64_libdir_override) {
+                               free((void *) consumerd64_libdir);
+                       }
+                       consumerd64_libdir = strdup(arg);
+                       if (!consumerd64_libdir) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+                       consumerd64_libdir_override = 1;
+               }
+       } else if (string_match(optname, "pidfile") || opt == 'p') {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-p, --pidfile");
+               } else {
+                       free(opt_pidfile);
+                       opt_pidfile = strdup(arg);
+                       if (!opt_pidfile) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "agent-tcp-port")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--agent-tcp-port");
+               } else {
+                       unsigned long v;
+
+                       if (!arg) {
+                               ret = -EINVAL;
+                               goto end;
+                       }
+                       errno = 0;
+                       v = strtoul(arg, NULL, 0);
+                       if (errno != 0 || !isdigit(arg[0])) {
+                               ERR("Wrong value in --agent-tcp-port parameter: %s", arg);
+                               return -1;
+                       }
+                       if (v == 0 || v >= 65535) {
+                               ERR("Port overflow in --agent-tcp-port parameter: %s", arg);
+                               return -1;
+                       }
+                       agent_tcp_port = (uint32_t) v;
+                       DBG3("Agent TCP port set to non default: %u", agent_tcp_port);
+               }
+       } else if (string_match(optname, "load") || opt == 'l') {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-l, --load");
+               } else {
+                       free(opt_load_session_path);
+                       opt_load_session_path = strdup(arg);
+                       if (!opt_load_session_path) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "kmod-probes")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--kmod-probes");
+               } else {
+                       free(kmod_probes_list);
+                       kmod_probes_list = strdup(arg);
+                       if (!kmod_probes_list) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "extra-kmod-probes")) {
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--extra-kmod-probes");
+               } else {
+                       free(kmod_extra_probes_list);
+                       kmod_extra_probes_list = strdup(arg);
+                       if (!kmod_extra_probes_list) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "config") || opt == 'f') {
+               /* This is handled in set_options() thus silent skip. */
+               goto end;
+       } else {
+               /* Unknown option or other error.
+                * Error is printed by getopt, just return */
+               ret = -1;
+       }
+
+end:
+       if (ret == -EINVAL) {
+               const char *opt_name = "unknown";
+               int i;
+
+               for (i = 0; i < sizeof(long_options) / sizeof(struct option);
+                       i++) {
+                       if (opt == long_options[i].val) {
+                               opt_name = long_options[i].name;
+                               break;
+                       }
+               }
+
+               WARN("Invalid argument provided for option \"%s\", using default value.",
+                       opt_name);
+       }
+
+       return ret;
+}
+
+/*
+ * config_entry_handler_cb used to handle options read from a config file.
+ * See config_entry_handler_cb comment in common/config/config.h for the
+ * return value conventions.
+ */
+static int config_entry_handler(const struct config_entry *entry, void *unused)
+{
+       int ret = 0, i;
+
+       if (!entry || !entry->name || !entry->value) {
+               ret = -EINVAL;
+               goto end;
+       }
+
+       /* Check if the option is to be ignored */
+       for (i = 0; i < sizeof(config_ignore_options) / sizeof(char *); i++) {
+               if (!strcmp(entry->name, config_ignore_options[i])) {
+                       goto end;
+               }
+       }
+
+       for (i = 0; i < (sizeof(long_options) / sizeof(struct option)) - 1;
+               i++) {
+
+               /* Ignore if not fully matched. */
+               if (strcmp(entry->name, long_options[i].name)) {
+                       continue;
+               }
+
+               /*
+                * If the option takes no argument on the command line, we have to
+                * check if the value is "true". We support non-zero numeric values,
+                * true, on and yes.
+                */
+               if (!long_options[i].has_arg) {
+                       ret = config_parse_value(entry->value);
+                       if (ret <= 0) {
+                               if (ret) {
+                                       WARN("Invalid configuration value \"%s\" for option %s",
+                                                       entry->value, entry->name);
+                               }
+                               /* False, skip boolean config option. */
+                               goto end;
+                       }
+               }
+
+               ret = set_option(long_options[i].val, entry->value, entry->name);
+               goto end;
+       }
+
+       WARN("Unrecognized option \"%s\" in daemon configuration file.", entry->name);
+
+end:
+       return ret;
+}
 
+/*
+ * daemon configuration loading and argument parsing
+ */
+static int set_options(int argc, char **argv)
+{
+       int ret = 0, c = 0, option_index = 0;
+       int orig_optopt = optopt, orig_optind = optind;
+       char *optstring;
+       const char *config_path = NULL;
+
+       optstring = utils_generate_optstring(long_options,
+                       sizeof(long_options) / sizeof(struct option));
+       if (!optstring) {
+               ret = -ENOMEM;
+               goto end;
+       }
+
+       /* Check for the --config option */
+       while ((c = getopt_long(argc, argv, optstring, long_options,
+                                       &option_index)) != -1) {
+               if (c == '?') {
+                       ret = -EINVAL;
+                       goto end;
+               } else if (c != 'f') {
+                       /* if not equal to --config option. */
+                       continue;
+               }
+
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-f, --config");
+               } else {
+                       config_path = utils_expand_path(optarg);
+                       if (!config_path) {
+                               ERR("Failed to resolve path: %s", optarg);
+                       }
+               }
+       }
+
+       ret = config_get_section_entries(config_path, config_section_name,
+                       config_entry_handler, NULL);
+       if (ret) {
+               if (ret > 0) {
+                       ERR("Invalid configuration option at line %i", ret);
+                       ret = -1;
+               }
+               goto end;
+       }
+
+       /* Reset getopt's global state */
+       optopt = orig_optopt;
+       optind = orig_optind;
        while (1) {
-               int option_index = 0;
-               c = getopt_long(argc, argv, "dhqvVSN" "a:c:g:s:C:E:D:F:Z:u:t:p:",
-                               long_options, &option_index);
+               option_index = -1;
+               /*
+                * getopt_long() will not set option_index if it encounters a
+                * short option.
+                */
+               c = getopt_long(argc, argv, optstring, long_options,
+                               &option_index);
                if (c == -1) {
                        break;
                }
 
-               switch (c) {
-               case 0:
-                       fprintf(stderr, "option %s", long_options[option_index].name);
-                       if (optarg) {
-                               fprintf(stderr, " with arg %s\n", optarg);
-                       }
-                       break;
-               case 'c':
-                       snprintf(client_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'a':
-                       snprintf(apps_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'd':
-                       opt_daemon = 1;
-                       break;
-               case 'g':
-                       opt_tracing_group = optarg;
-                       break;
-               case 'h':
-                       usage();
-                       exit(EXIT_FAILURE);
-               case 'V':
-                       fprintf(stdout, "%s\n", VERSION);
-                       exit(EXIT_SUCCESS);
-               case 'S':
-                       opt_sig_parent = 1;
-                       break;
-               case 'E':
-                       snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'C':
-                       snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'F':
-                       snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'D':
-                       snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'H':
-                       snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'G':
-                       snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX, "%s", optarg);
-                       break;
-               case 'N':
-                       opt_no_kernel = 1;
-                       break;
-               case 'q':
-                       lttng_opt_quiet = 1;
-                       break;
-               case 'v':
-                       /* Verbose level can increase using multiple -v */
-                       lttng_opt_verbose += 1;
-                       break;
-               case 'Z':
-                       opt_verbose_consumer += 1;
-                       break;
-               case 'u':
-                       consumerd32_bin= optarg;
-                       break;
-               case 'U':
-                       consumerd32_libdir = optarg;
-                       break;
-               case 't':
-                       consumerd64_bin = optarg;
-                       break;
-               case 'T':
-                       consumerd64_libdir = optarg;
-                       break;
-               case 'p':
-                       opt_pidfile = optarg;
+               /*
+                * Pass NULL as the long option name if popt left the index
+                * unset.
+                */
+               ret = set_option(c, optarg,
+                               option_index < 0 ? NULL :
+                               long_options[option_index].name);
+               if (ret < 0) {
                        break;
-               default:
-                       /* Unknown option or other error.
-                        * Error is printed by getopt, just return */
-                       return -1;
                }
        }
 
-       return 0;
+end:
+       free(optstring);
+       return ret;
 }
 
 /*
@@ -3652,14 +5056,7 @@ static int set_permissions(char *rundir)
        int ret;
        gid_t gid;
 
-       ret = allowed_group();
-       if (ret < 0) {
-               WARN("No tracing group detected");
-               ret = 0;
-               goto end;
-       }
-
-       gid = ret;
+       gid = utils_get_group_id(tracing_group_name);
 
        /* Set lttng run dir */
        ret = chown(rundir, 0, gid);
@@ -3668,8 +5065,12 @@ static int set_permissions(char *rundir)
                PERROR("chown");
        }
 
-       /* Ensure tracing group can search the run dir */
-       ret = chmod(rundir, S_IRWXU | S_IXGRP | S_IXOTH);
+       /*
+        * Ensure all applications and tracing group can search the run
+        * dir. Allow everyone to read the directory, since it does not
+        * buy us anything to hide its content.
+        */
+       ret = chmod(rundir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
        if (ret < 0) {
                ERR("Unable to set permissions on %s", rundir);
                PERROR("chmod");
@@ -3683,21 +5084,21 @@ static int set_permissions(char *rundir)
        }
 
        /* kconsumer error socket path */
-       ret = chown(kconsumer_data.err_unix_sock_path, 0, gid);
+       ret = chown(kconsumer_data.err_unix_sock_path, 0, 0);
        if (ret < 0) {
                ERR("Unable to set group on %s", kconsumer_data.err_unix_sock_path);
                PERROR("chown");
        }
 
        /* 64-bit ustconsumer error socket path */
-       ret = chown(ustconsumer64_data.err_unix_sock_path, 0, gid);
+       ret = chown(ustconsumer64_data.err_unix_sock_path, 0, 0);
        if (ret < 0) {
                ERR("Unable to set group on %s", ustconsumer64_data.err_unix_sock_path);
                PERROR("chown");
        }
 
        /* 32-bit ustconsumer compat32 error socket path */
-       ret = chown(ustconsumer32_data.err_unix_sock_path, 0, gid);
+       ret = chown(ustconsumer32_data.err_unix_sock_path, 0, 0);
        if (ret < 0) {
                ERR("Unable to set group on %s", ustconsumer32_data.err_unix_sock_path);
                PERROR("chown");
@@ -3705,7 +5106,6 @@ static int set_permissions(char *rundir)
 
        DBG("All permissions are set");
 
-end:
        return ret;
 }
 
@@ -3742,7 +5142,7 @@ static int set_consumer_sockets(struct consumer_data *consumer_data,
        int ret;
        char path[PATH_MAX];
 
-    switch (consumer_data->type) {
+       switch (consumer_data->type) {
        case LTTNG_CONSUMER_KERNEL:
                snprintf(path, PATH_MAX, DEFAULT_KCONSUMERD_PATH, rundir);
                break;
@@ -3760,14 +5160,22 @@ static int set_consumer_sockets(struct consumer_data *consumer_data,
 
        DBG2("Creating consumer directory: %s", path);
 
-       ret = mkdir(path, S_IRWXU);
+       ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP);
        if (ret < 0) {
                if (errno != EEXIST) {
                        PERROR("mkdir");
                        ERR("Failed to create %s", path);
                        goto error;
                }
-               ret = -1;
+               ret = -1;
+       }
+       if (is_root) {
+               ret = chown(path, 0, utils_get_group_id(tracing_group_name));
+               if (ret < 0) {
+                       ERR("Unable to set group on %s", path);
+                       PERROR("chown");
+                       goto error;
+               }
        }
 
        /* Create the kconsumerd error unix socket */
@@ -3779,6 +5187,16 @@ static int set_consumer_sockets(struct consumer_data *consumer_data,
                goto error;
        }
 
+       /*
+        * Set the CLOEXEC flag. Return code is useless because either way, the
+        * show must go on.
+        */
+       ret = utils_set_fd_cloexec(consumer_data->err_sock);
+       if (ret < 0) {
+               PERROR("utils_set_fd_cloexec");
+               /* continue anyway */
+       }
+
        /* File permission MUST be 660 */
        ret = chmod(consumer_data->err_unix_sock_path,
                        S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
@@ -3812,6 +5230,9 @@ static void sighandler(int sig)
                DBG("SIGTERM caught");
                stop_threads();
                break;
+       case SIGUSR1:
+               CMM_STORE_SHARED(recv_child_signal, 1);
+               break;
        default:
                break;
        }
@@ -3850,7 +5271,12 @@ static int set_signal_handler(void)
                return ret;
        }
 
-       DBG("Signal handler set for SIGTERM, SIGPIPE and SIGINT");
+       if ((ret = sigaction(SIGUSR1, &sa, NULL)) < 0) {
+               PERROR("sigaction");
+               return ret;
+       }
+
+       DBG("Signal handler set for SIGTERM, SIGUSR1, SIGPIPE and SIGINT");
 
        return ret;
 }
@@ -3877,7 +5303,7 @@ static void set_ulimit(void)
 /*
  * Write pidfile using the rundir and opt_pidfile.
  */
-static void write_pidfile(void)
+static int write_pidfile(void)
 {
        int ret;
        char pidfile_path[PATH_MAX];
@@ -3897,13 +5323,55 @@ static void write_pidfile(void)
        }
 
        /*
-        * Create pid file in rundir. Return value is of no importance. The
-        * execution will continue even though we are not able to write the file.
+        * Create pid file in rundir.
         */
-       (void) utils_create_pid_file(getpid(), pidfile_path);
+       ret = utils_create_pid_file(getpid(), pidfile_path);
+error:
+       return ret;
+}
+
+/*
+ * Create lockfile using the rundir and return its fd.
+ */
+static int create_lockfile(void)
+{
+       int ret;
+       char lockfile_path[PATH_MAX];
 
+       ret = generate_lock_file_path(lockfile_path, sizeof(lockfile_path));
+       if (ret < 0) {
+               goto error;
+       }
+
+       ret = utils_create_lock_file(lockfile_path);
 error:
-       return;
+       return ret;
+}
+
+/*
+ * Write agent TCP port using the rundir.
+ */
+static int write_agent_port(void)
+{
+       int ret;
+       char path[PATH_MAX];
+
+       assert(rundir);
+
+       ret = snprintf(path, sizeof(path), "%s/"
+                       DEFAULT_LTTNG_SESSIOND_AGENTPORT_FILE, rundir);
+       if (ret < 0) {
+               PERROR("snprintf agent port path");
+               goto error;
+       }
+
+       /*
+        * Create TCP agent port file in rundir.
+        */
+       ret = utils_create_pid_file(agent_tcp_port, path);
+
+error:
+       return ret;
 }
 
 /*
@@ -3911,7 +5379,7 @@ error:
  */
 int main(int argc, char **argv)
 {
-       int ret = 0;
+       int ret = 0, retval = 0;
        void *status;
        const char *home_path, *env_app_timeout;
 
@@ -3919,41 +5387,102 @@ int main(int argc, char **argv)
 
        rcu_register_thread();
 
+       if (set_signal_handler()) {
+               retval = -1;
+               goto exit_set_signal_handler;
+       }
+
        setup_consumerd_path();
 
-       /* Parse arguments */
+       page_size = sysconf(_SC_PAGESIZE);
+       if (page_size < 0) {
+               PERROR("sysconf _SC_PAGESIZE");
+               page_size = LONG_MAX;
+               WARN("Fallback page size to %ld", page_size);
+       }
+
+       /*
+        * Parse arguments and load the daemon configuration file.
+        *
+        * We have an exit_options exit path to free memory reserved by
+        * set_options. This is needed because the rest of sessiond_cleanup()
+        * depends on ht_cleanup_thread, which depends on lttng_daemonize, which
+        * depends on set_options.
+        */
        progname = argv[0];
-       if ((ret = parse_args(argc, argv)) < 0) {
-               goto error;
+       if (set_options(argc, argv)) {
+               retval = -1;
+               goto exit_options;
        }
 
        /* Daemonize */
-       if (opt_daemon) {
+       if (opt_daemon || opt_background) {
                int i;
 
-               /*
-                * fork
-                * child: setsid, close FD 0, 1, 2, chdir /
-                * parent: exit (if fork is successful)
-                */
-               ret = daemon(0, 0);
+               ret = lttng_daemonize(&child_ppid, &recv_child_signal,
+                       !opt_background);
                if (ret < 0) {
-                       PERROR("daemon");
-                       goto error;
+                       retval = -1;
+                       goto exit_options;
                }
+
                /*
-                * We are in the child. Make sure all other file
-                * descriptors are closed, in case we are called with
-                * more opened file descriptors than the standard ones.
+                * We are in the child. Make sure all other file descriptors are
+                * closed, in case we are called with more opened file
+                * descriptors than the standard ones.
                 */
                for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
                        (void) close(i);
                }
        }
 
+       /*
+        * Starting from here, we can create threads. This needs to be after
+        * lttng_daemonize due to RCU.
+        */
+
+       /*
+        * Initialize the health check subsystem. This call should set the
+        * appropriate time values.
+        */
+       health_sessiond = health_app_create(NR_HEALTH_SESSIOND_TYPES);
+       if (!health_sessiond) {
+               PERROR("health_app_create error");
+               retval = -1;
+               goto exit_health_sessiond_cleanup;
+       }
+
+       if (init_ht_cleanup_quit_pipe()) {
+               retval = -1;
+               goto exit_ht_cleanup_quit_pipe;
+       }
+
+       /* Setup the thread ht_cleanup communication pipe. */
+       if (utils_create_pipe_cloexec(ht_cleanup_pipe)) {
+               retval = -1;
+               goto exit_ht_cleanup_pipe;
+       }
+
+       /* Set up max poll set size */
+       if (lttng_poll_set_max_size()) {
+               retval = -1;
+               goto exit_set_max_size;
+       }
+
+       /* Create thread to clean up RCU hash tables */
+       ret = pthread_create(&ht_cleanup_thread, NULL,
+                       thread_ht_cleanup, (void *) NULL);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create ht_cleanup");
+               retval = -1;
+               goto exit_ht_cleanup;
+       }
+
        /* Create thread quit pipe */
-       if ((ret = init_thread_quit_pipe()) < 0) {
-               goto error;
+       if (init_thread_quit_pipe()) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Check if daemon is UID = 0 */
@@ -3961,51 +5490,80 @@ int main(int argc, char **argv)
 
        if (is_root) {
                rundir = strdup(DEFAULT_LTTNG_RUNDIR);
+               if (!rundir) {
+                       retval = -1;
+                       goto exit_init_data;
+               }
 
                /* Create global run dir with root access */
-               ret = create_lttng_rundir(rundir);
-               if (ret < 0) {
-                       goto error;
+               if (create_lttng_rundir(rundir)) {
+                       retval = -1;
+                       goto exit_init_data;
                }
 
                if (strlen(apps_unix_sock_path) == 0) {
-                       snprintf(apps_unix_sock_path, PATH_MAX,
+                       ret = snprintf(apps_unix_sock_path, PATH_MAX,
                                        DEFAULT_GLOBAL_APPS_UNIX_SOCK);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
 
                if (strlen(client_unix_sock_path) == 0) {
-                       snprintf(client_unix_sock_path, PATH_MAX,
+                       ret = snprintf(client_unix_sock_path, PATH_MAX,
                                        DEFAULT_GLOBAL_CLIENT_UNIX_SOCK);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
 
                /* Set global SHM for ust */
                if (strlen(wait_shm_path) == 0) {
-                       snprintf(wait_shm_path, PATH_MAX,
+                       ret = snprintf(wait_shm_path, PATH_MAX,
                                        DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
 
                if (strlen(health_unix_sock_path) == 0) {
-                       snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
+                       ret = snprintf(health_unix_sock_path,
+                                       sizeof(health_unix_sock_path),
                                        DEFAULT_GLOBAL_HEALTH_UNIX_SOCK);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
 
                /* Setup kernel consumerd path */
-               snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX,
+               ret = snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX,
                                DEFAULT_KCONSUMERD_ERR_SOCK_PATH, rundir);
-               snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX,
+               if (ret < 0) {
+                       retval = -1;
+                       goto exit_init_data;
+               }
+               ret = snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX,
                                DEFAULT_KCONSUMERD_CMD_SOCK_PATH, rundir);
+               if (ret < 0) {
+                       retval = -1;
+                       goto exit_init_data;
+               }
 
                DBG2("Kernel consumer err path: %s",
                                kconsumer_data.err_unix_sock_path);
                DBG2("Kernel consumer cmd path: %s",
                                kconsumer_data.cmd_unix_sock_path);
        } else {
-               home_path = get_home_dir();
+               home_path = utils_get_home_dir();
                if (home_path == NULL) {
                        /* TODO: Add --socket PATH option */
                        ERR("Can't get HOME directory for sockets creation.");
-                       ret = -EPERM;
-                       goto error;
+                       retval = -1;
+                       goto exit_init_data;
                }
 
                /*
@@ -4014,52 +5572,90 @@ int main(int argc, char **argv)
                 */
                ret = asprintf(&rundir, DEFAULT_LTTNG_HOME_RUNDIR, home_path);
                if (ret < 0) {
-                       ret = -ENOMEM;
-                       goto error;
+                       retval = -1;
+                       goto exit_init_data;
                }
 
-               ret = create_lttng_rundir(rundir);
-               if (ret < 0) {
-                       goto error;
+               if (create_lttng_rundir(rundir)) {
+                       retval = -1;
+                       goto exit_init_data;
                }
 
                if (strlen(apps_unix_sock_path) == 0) {
-                       snprintf(apps_unix_sock_path, PATH_MAX,
-                                       DEFAULT_HOME_APPS_UNIX_SOCK, home_path);
+                       ret = snprintf(apps_unix_sock_path, PATH_MAX,
+                                       DEFAULT_HOME_APPS_UNIX_SOCK,
+                                       home_path);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
 
                /* Set the cli tool unix socket path */
                if (strlen(client_unix_sock_path) == 0) {
-                       snprintf(client_unix_sock_path, PATH_MAX,
-                                       DEFAULT_HOME_CLIENT_UNIX_SOCK, home_path);
+                       ret = snprintf(client_unix_sock_path, PATH_MAX,
+                                       DEFAULT_HOME_CLIENT_UNIX_SOCK,
+                                       home_path);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
 
                /* Set global SHM for ust */
                if (strlen(wait_shm_path) == 0) {
-                       snprintf(wait_shm_path, PATH_MAX,
-                                       DEFAULT_HOME_APPS_WAIT_SHM_PATH, geteuid());
+                       ret = snprintf(wait_shm_path, PATH_MAX,
+                                       DEFAULT_HOME_APPS_WAIT_SHM_PATH,
+                                       getuid());
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
 
                /* Set health check Unix path */
                if (strlen(health_unix_sock_path) == 0) {
-                       snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
-                                       DEFAULT_HOME_HEALTH_UNIX_SOCK, home_path);
+                       ret = snprintf(health_unix_sock_path,
+                                       sizeof(health_unix_sock_path),
+                                       DEFAULT_HOME_HEALTH_UNIX_SOCK,
+                                       home_path);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                }
        }
 
+       lockfile_fd = create_lockfile();
+       if (lockfile_fd < 0) {
+               retval = -1;
+               goto exit_init_data;
+       }
+
        /* Set consumer initial state */
        kernel_consumerd_state = CONSUMER_STOPPED;
        ust_consumerd_state = CONSUMER_STOPPED;
 
        DBG("Client socket path %s", client_unix_sock_path);
        DBG("Application socket path %s", apps_unix_sock_path);
+       DBG("Application wait path %s", wait_shm_path);
        DBG("LTTng run directory path: %s", rundir);
 
        /* 32 bits consumerd path setup */
-       snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX,
+       ret = snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX,
                        DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH, rundir);
-       snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX,
+       if (ret < 0) {
+               PERROR("snprintf 32-bit consumer error socket path");
+               retval = -1;
+               goto exit_init_data;
+       }
+       ret = snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX,
                        DEFAULT_USTCONSUMERD32_CMD_SOCK_PATH, rundir);
+       if (ret < 0) {
+               PERROR("snprintf 32-bit consumer command socket path");
+               retval = -1;
+               goto exit_init_data;
+       }
 
        DBG2("UST consumer 32 bits err path: %s",
                        ustconsumer32_data.err_unix_sock_path);
@@ -4067,10 +5663,20 @@ int main(int argc, char **argv)
                        ustconsumer32_data.cmd_unix_sock_path);
 
        /* 64 bits consumerd path setup */
-       snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX,
+       ret = snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX,
                        DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH, rundir);
-       snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX,
+       if (ret < 0) {
+               PERROR("snprintf 64-bit consumer error socket path");
+               retval = -1;
+               goto exit_init_data;
+       }
+       ret = snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX,
                        DEFAULT_USTCONSUMERD64_CMD_SOCK_PATH, rundir);
+       if (ret < 0) {
+               PERROR("snprintf 64-bit consumer command socket path");
+               retval = -1;
+               goto exit_init_data;
+       }
 
        DBG2("UST consumer 64 bits err path: %s",
                        ustconsumer64_data.err_unix_sock_path);
@@ -4080,22 +5686,35 @@ int main(int argc, char **argv)
        /*
         * See if daemon already exist.
         */
-       if ((ret = check_existing_daemon()) < 0) {
+       if (check_existing_daemon()) {
                ERR("Already running daemon.\n");
                /*
                 * We do not goto exit because we must not cleanup()
                 * because a daemon is already running.
                 */
-               goto error;
+               retval = -1;
+               goto exit_init_data;
        }
 
        /*
         * Init UST app hash table. Alloc hash table before this point since
         * cleanup() can get called after that point.
         */
-       ust_app_ht_alloc();
+       if (ust_app_ht_alloc()) {
+               ERR("Failed to allocate UST app hash table");
+               retval = -1;
+               goto exit_init_data;
+       }
 
-       /* After this point, we can safely call cleanup() with "goto exit" */
+       /*
+        * Initialize agent app hash table. We allocate the hash table here
+        * since cleanup() can get called after this point.
+        */
+       if (agent_app_ht_alloc()) {
+               ERR("Failed to allocate Agent app hash table");
+               retval = -1;
+               goto exit_init_data;
+       }
 
        /*
         * These actions must be executed as root. We do that *after* setting up
@@ -4104,14 +5723,22 @@ int main(int argc, char **argv)
         * kernel tracer.
         */
        if (is_root) {
-               ret = set_consumer_sockets(&kconsumer_data, rundir);
-               if (ret < 0) {
-                       goto exit;
+               if (set_consumer_sockets(&kconsumer_data, rundir)) {
+                       retval = -1;
+                       goto exit_init_data;
                }
 
                /* Setup kernel tracer */
                if (!opt_no_kernel) {
                        init_kernel_tracer();
+                       if (kernel_tracer_fd >= 0) {
+                               ret = syscall_init_table();
+                               if (ret < 0) {
+                                       ERR("Unable to populate syscall table. "
+                                               "Syscall tracing won't work "
+                                               "for this session daemon.");
+                               }
+                       }
                }
 
                /* Set ulimit for open files */
@@ -4120,28 +5747,26 @@ int main(int argc, char **argv)
        /* init lttng_fd tracking must be done after set_ulimit. */
        lttng_fd_init();
 
-       ret = set_consumer_sockets(&ustconsumer64_data, rundir);
-       if (ret < 0) {
-               goto exit;
-       }
-
-       ret = set_consumer_sockets(&ustconsumer32_data, rundir);
-       if (ret < 0) {
-               goto exit;
+       if (set_consumer_sockets(&ustconsumer64_data, rundir)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
-       if ((ret = set_signal_handler()) < 0) {
-               goto exit;
+       if (set_consumer_sockets(&ustconsumer32_data, rundir)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Setup the needed unix socket */
-       if ((ret = init_daemon_socket()) < 0) {
-               goto exit;
+       if (init_daemon_socket()) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Set credentials to socket */
-       if (is_root && ((ret = set_permissions(rundir)) < 0)) {
-               goto exit;
+       if (is_root && set_permissions(rundir)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Get parent pid if -S, --sig-parent is specified. */
@@ -4151,28 +5776,37 @@ int main(int argc, char **argv)
 
        /* Setup the kernel pipe for waking up the kernel thread */
        if (is_root && !opt_no_kernel) {
-               if ((ret = utils_create_pipe_cloexec(kernel_poll_pipe)) < 0) {
-                       goto exit;
+               if (utils_create_pipe_cloexec(kernel_poll_pipe)) {
+                       retval = -1;
+                       goto exit_init_data;
                }
        }
 
        /* Setup the thread apps communication pipe. */
-       if ((ret = utils_create_pipe_cloexec(apps_cmd_pipe)) < 0) {
-               goto exit;
+       if (utils_create_pipe_cloexec(apps_cmd_pipe)) {
+               retval = -1;
+               goto exit_init_data;
+       }
+
+       /* Setup the thread apps notify communication pipe. */
+       if (utils_create_pipe_cloexec(apps_cmd_notify_pipe)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
+       /* Initialize global buffer per UID and PID registry. */
+       buffer_reg_init_uid_registry();
+       buffer_reg_init_pid_registry();
+
        /* Init UST command queue. */
-       cds_wfq_init(&ust_cmd_queue.queue);
+       cds_wfcq_init(&ust_cmd_queue.head, &ust_cmd_queue.tail);
 
        /*
-        * Get session list pointer. This pointer MUST NOT be free(). This list is
-        * statically declared in session.c
+        * Get session list pointer. This pointer MUST NOT be free'd. This list
+        * is statically declared in session.c
         */
        session_list_ptr = session_get_list();
 
-       /* Set up max poll set size */
-       lttng_poll_set_max_size();
-
        cmd_init();
 
        /* Check for the application socket timeout env variable. */
@@ -4183,130 +5817,253 @@ int main(int argc, char **argv)
                app_socket_timeout = DEFAULT_APP_SOCKET_RW_TIMEOUT;
        }
 
-       write_pidfile();
+       ret = write_pidfile();
+       if (ret) {
+               ERR("Error in write_pidfile");
+               retval = -1;
+               goto exit_init_data;
+       }
+       ret = write_agent_port();
+       if (ret) {
+               ERR("Error in write_agent_port");
+               retval = -1;
+               goto exit_init_data;
+       }
+
+       /* Initialize communication library */
+       lttcomm_init();
+       /* Initialize TCP timeout values */
+       lttcomm_inet_init();
 
-       /* Create thread to manage the client socket */
+       if (load_session_init_data(&load_info) < 0) {
+               retval = -1;
+               goto exit_init_data;
+       }
+       load_info->path = opt_load_session_path;
+
+       /* Create health-check thread */
        ret = pthread_create(&health_thread, NULL,
                        thread_manage_health, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create health");
+               retval = -1;
                goto exit_health;
        }
 
        /* Create thread to manage the client socket */
        ret = pthread_create(&client_thread, NULL,
                        thread_manage_clients, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create clients");
+               retval = -1;
                goto exit_client;
        }
 
        /* Create thread to dispatch registration */
        ret = pthread_create(&dispatch_thread, NULL,
                        thread_dispatch_ust_registration, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create dispatch");
+               retval = -1;
                goto exit_dispatch;
        }
 
        /* Create thread to manage application registration. */
        ret = pthread_create(&reg_apps_thread, NULL,
                        thread_registration_apps, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create registration");
+               retval = -1;
                goto exit_reg_apps;
        }
 
        /* Create thread to manage application socket */
        ret = pthread_create(&apps_thread, NULL,
                        thread_manage_apps, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create apps");
+               retval = -1;
                goto exit_apps;
        }
 
+       /* Create thread to manage application notify socket */
+       ret = pthread_create(&apps_notify_thread, NULL,
+                       ust_thread_manage_notify, (void *) NULL);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create notify");
+               retval = -1;
+               goto exit_apps_notify;
+       }
+
+       /* Create agent registration thread. */
+       ret = pthread_create(&agent_reg_thread, NULL,
+                       agent_thread_manage_registration, (void *) NULL);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create agent");
+               retval = -1;
+               goto exit_agent_reg;
+       }
+
        /* Don't start this thread if kernel tracing is not requested nor root */
        if (is_root && !opt_no_kernel) {
                /* Create kernel thread to manage kernel event */
                ret = pthread_create(&kernel_thread, NULL,
                                thread_manage_kernel, (void *) NULL);
-               if (ret != 0) {
+               if (ret) {
+                       errno = ret;
                        PERROR("pthread_create kernel");
+                       retval = -1;
                        goto exit_kernel;
                }
+       }
+
+       /* Create session loading thread. */
+       ret = pthread_create(&load_session_thread, NULL, thread_load_session,
+                       load_info);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create load_session_thread");
+               retval = -1;
+               goto exit_load_session;
+       }
+
+       /*
+        * This is where we start awaiting program completion (e.g. through
+        * signal that asks threads to teardown).
+        */
+
+       ret = pthread_join(load_session_thread, &status);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join load_session_thread");
+               retval = -1;
+       }
+exit_load_session:
 
+       if (is_root && !opt_no_kernel) {
                ret = pthread_join(kernel_thread, &status);
-               if (ret != 0) {
+               if (ret) {
+                       errno = ret;
                        PERROR("pthread_join");
-                       goto error;     /* join error, exit without cleanup */
+                       retval = -1;
                }
        }
-
 exit_kernel:
-       ret = pthread_join(apps_thread, &status);
-       if (ret != 0) {
-               PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+
+       ret = pthread_join(agent_reg_thread, &status);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join agent");
+               retval = -1;
+       }
+exit_agent_reg:
+
+       ret = pthread_join(apps_notify_thread, &status);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join apps notify");
+               retval = -1;
        }
+exit_apps_notify:
 
+       ret = pthread_join(apps_thread, &status);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join apps");
+               retval = -1;
+       }
 exit_apps:
+
        ret = pthread_join(reg_apps_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_reg_apps:
+
+       /*
+        * Join dispatch thread after joining reg_apps_thread to ensure
+        * we don't leak applications in the queue.
+        */
        ret = pthread_join(dispatch_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_dispatch:
+
        ret = pthread_join(client_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
-       }
-
-       ret = join_consumer_thread(&kconsumer_data);
-       if (ret != 0) {
-               PERROR("join_consumer");
-               goto error;     /* join error, exit without cleanup */
-       }
-
-       ret = join_consumer_thread(&ustconsumer32_data);
-       if (ret != 0) {
-               PERROR("join_consumer ust32");
-               goto error;     /* join error, exit without cleanup */
-       }
-
-       ret = join_consumer_thread(&ustconsumer64_data);
-       if (ret != 0) {
-               PERROR("join_consumer ust64");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_client:
+
        ret = pthread_join(health_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join health thread");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_health:
-exit:
+
+exit_init_data:
        /*
-        * cleanup() is called when no other thread is running.
+        * sessiond_cleanup() is called when no other thread is running, except
+        * the ht_cleanup thread, which is needed to destroy the hash tables.
         */
        rcu_thread_online();
-       cleanup();
+       sessiond_cleanup();
        rcu_thread_offline();
        rcu_unregister_thread();
-       if (!ret) {
+
+       ret = notify_thread_pipe(ht_cleanup_quit_pipe[1]);
+       if (ret < 0) {
+               ERR("write error on ht_cleanup quit pipe");
+               retval = -1;
+       }
+
+       ret = pthread_join(ht_cleanup_thread, &status);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join ht cleanup thread");
+               retval = -1;
+       }
+exit_ht_cleanup:
+exit_set_max_size:
+
+       utils_close_pipe(ht_cleanup_pipe);
+exit_ht_cleanup_pipe:
+
+       /*
+        * Close the ht_cleanup quit pipe.
+        */
+       utils_close_pipe(ht_cleanup_quit_pipe);
+exit_ht_cleanup_quit_pipe:
+
+       health_app_destroy(health_sessiond);
+exit_health_sessiond_cleanup:
+
+exit_options:
+       sessiond_cleanup_options();
+
+exit_set_signal_handler:
+       /* Ensure all prior call_rcu are done. */
+       rcu_barrier();
+
+       if (!retval) {
                exit(EXIT_SUCCESS);
+       } else {
+               exit(EXIT_FAILURE);
        }
-error:
-       exit(EXIT_FAILURE);
 }
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