X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=ead0d7fecbc6d15f03ab120ff9f3524b063bf454;hb=867942fdcdf016a65df7165b4b8135801e2832c2;hp=7cd6a227d66c3bede0f7e244a02038c2c8de668b;hpb=4c62d8d195fb07d3bc64b6a81836d2a5be4abcf3;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 7cd6a227..ead0d7fe 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -20,13 +20,15 @@
  */
 
 #define _LGPL_SOURCE
-#define _GNU_SOURCE
+#include <stddef.h>
+#include <stdint.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <dlfcn.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
@@ -35,10 +37,13 @@
 #include <time.h>
 #include <assert.h>
 #include <signal.h>
+#include <limits.h>
 #include <urcu/uatomic.h>
-#include <urcu/futex.h>
+#include "futex.h"
 #include <urcu/compiler.h>
+#include <lttng/urcu/urcu-ust.h>
 
+#include <lttng/align.h>
 #include <lttng/ust-events.h>
 #include <lttng/ust-abi.h>
 #include <lttng/ust.h>
@@ -52,11 +57,15 @@
 #include "tracepoint-internal.h"
 #include "lttng-tracer-core.h"
 #include "compat.h"
-#include "../libringbuffer/tlsfixup.h"
+#include "../libringbuffer/rb-init.h"
 #include "lttng-ust-statedump.h"
 #include "clock.h"
 #include "../libringbuffer/getcpu.h"
 #include "getenv.h"
+#include "ust-events-internal.h"
+
+/* Concatenate lttng ust shared library name with its major version number. */
+#define LTTNG_UST_LIB_SO_NAME "liblttng-ust.so." __ust_stringify(CONFIG_LTTNG_UST_LIBRARY_VERSION_MAJOR)
 
 /*
  * Has lttng ust comm constructor been called ?
@@ -81,6 +90,8 @@ static int initialized;
  *
  * ust_lock nests within the dynamic loader lock (within glibc) because
  * it is taken within the library constructor.
+ *
+ * The ust fd tracker lock nests within the ust_mutex.
  */
 static pthread_mutex_t ust_mutex = PTHREAD_MUTEX_INITIALIZER;
 
@@ -223,7 +234,11 @@ static sem_t constructor_wait;
 /*
  * Doing this for both the global and local sessiond.
  */
-static int sem_count = { 2 };
+enum {
+	sem_count_initial_value = 4,
+};
+
+static int sem_count = sem_count_initial_value;
 
 /*
  * Counting nesting within lttng-ust. Used to ensure that calling fork()
@@ -238,7 +253,7 @@ struct sock_info {
 	const char *name;
 	pthread_t ust_listener;	/* listener thread */
 	int root_handle;
-	int constructor_sem_posted;
+	int registration_done;
 	int allowed;
 	int global;
 	int thread_active;
@@ -251,6 +266,9 @@ struct sock_info {
 	char *wait_shm_mmap;
 	/* Keep track of lazy state dump not performed yet. */
 	int statedump_pending;
+	int initial_statedump_done;
+	/* Keep procname for statedump */
+	char procname[LTTNG_UST_ABI_PROCNAME_LEN];
 };
 
 /* Socket from app (connect) to session daemon (listen) for communication */
@@ -259,7 +277,8 @@ struct sock_info global_apps = {
 	.global = 1,
 
 	.root_handle = -1,
-	.allowed = 1,
+	.registration_done = 0,
+	.allowed = 0,
 	.thread_active = 0,
 
 	.sock_path = LTTNG_DEFAULT_RUNDIR "/" LTTNG_UST_SOCK_FILENAME,
@@ -269,6 +288,8 @@ struct sock_info global_apps = {
 	.wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME,
 
 	.statedump_pending = 0,
+	.initial_statedump_done = 0,
+	.procname[0] = '\0'
 };
 
 /* TODO: allow global_apps_sock_path override */
@@ -277,6 +298,7 @@ struct sock_info local_apps = {
 	.name = "local",
 	.global = 0,
 	.root_handle = -1,
+	.registration_done = 0,
 	.allowed = 0,	/* Check setuid bit first */
 	.thread_active = 0,
 
@@ -284,6 +306,8 @@ struct sock_info local_apps = {
 	.notify_socket = -1,
 
 	.statedump_pending = 0,
+	.initial_statedump_done = 0,
+	.procname[0] = '\0'
 };
 
 static int wait_poll_fallback;
@@ -298,6 +322,8 @@ static const char *cmd_name_mapping[] = {
 	[ LTTNG_UST_REGISTER_DONE ] = "Registration Done",
 	[ LTTNG_UST_TRACEPOINT_FIELD_LIST ] = "Create Tracepoint Field List",
 
+	[ LTTNG_UST_EVENT_NOTIFIER_GROUP_CREATE ] = "Create event notifier group",
+
 	/* Session FD commands */
 	[ LTTNG_UST_CHANNEL ] = "Create Channel",
 	[ LTTNG_UST_SESSION_START ] = "Start Session",
@@ -322,6 +348,16 @@ static const char *cmd_name_mapping[] = {
 	/* Event FD commands */
 	[ LTTNG_UST_FILTER ] = "Create Filter",
 	[ LTTNG_UST_EXCLUSION ] = "Add exclusions to event",
+
+	/* Event notifier group commands */
+	[ LTTNG_UST_EVENT_NOTIFIER_CREATE ] = "Create event notifier",
+
+	/* Session and event notifier group commands */
+	[ LTTNG_UST_COUNTER ] = "Create Counter",
+
+	/* Counter commands */
+	[ LTTNG_UST_COUNTER_GLOBAL ] = "Create Counter Global",
+	[ LTTNG_UST_COUNTER_CPU ] = "Create Counter CPU",
 };
 
 static const char *str_timeout;
@@ -337,6 +373,12 @@ extern void lttng_ring_buffer_client_overwrite_rt_exit(void);
 extern void lttng_ring_buffer_client_discard_exit(void);
 extern void lttng_ring_buffer_client_discard_rt_exit(void);
 extern void lttng_ring_buffer_metadata_client_exit(void);
+extern void lttng_counter_client_percpu_32_modular_init(void);
+extern void lttng_counter_client_percpu_32_modular_exit(void);
+extern void lttng_counter_client_percpu_64_modular_init(void);
+extern void lttng_counter_client_percpu_64_modular_exit(void);
+
+static char *get_map_shm(struct sock_info *sock_info);
 
 ssize_t lttng_ust_read(int fd, void *buf, size_t len)
 {
@@ -365,11 +407,11 @@ const char *get_lttng_home_dir(void)
 {
        const char *val;
 
-       val = (const char *) lttng_secure_getenv("LTTNG_HOME");
+       val = (const char *) lttng_getenv("LTTNG_HOME");
        if (val != NULL) {
                return val;
        }
-       return (const char *) lttng_secure_getenv("HOME");
+       return (const char *) lttng_getenv("HOME");
 }
 
 /*
@@ -393,8 +435,7 @@ void lttng_fixup_ust_mutex_nest_tls(void)
 static
 void lttng_fixup_urcu_bp_tls(void)
 {
-	rcu_read_lock();
-	rcu_read_unlock();
+	(void) lttng_ust_urcu_read_ongoing();
 }
 
 void lttng_ust_fixup_tls(void)
@@ -405,7 +446,13 @@ void lttng_ust_fixup_tls(void)
 	lttng_fixup_nest_count_tls();
 	lttng_fixup_procname_tls();
 	lttng_fixup_ust_mutex_nest_tls();
+	lttng_ust_fixup_perf_counter_tls();
 	lttng_ust_fixup_fd_tracker_tls();
+	lttng_fixup_cgroup_ns_tls();
+	lttng_fixup_ipc_ns_tls();
+	lttng_fixup_net_ns_tls();
+	lttng_fixup_time_ns_tls();
+	lttng_fixup_uts_ns_tls();
 }
 
 int lttng_get_notify_socket(void *owner)
@@ -415,6 +462,15 @@ int lttng_get_notify_socket(void *owner)
 	return info->notify_socket;
 }
 
+
+LTTNG_HIDDEN
+char* lttng_ust_sockinfo_get_procname(void *owner)
+{
+	struct sock_info *info = owner;
+
+	return info->procname;
+}
+
 static
 void print_cmd(int cmd, int handle)
 {
@@ -429,25 +485,49 @@ void print_cmd(int cmd, int handle)
 		lttng_ust_obj_get_name(handle), handle);
 }
 
+static
+int setup_global_apps(void)
+{
+	int ret = 0;
+	assert(!global_apps.wait_shm_mmap);
+
+	global_apps.wait_shm_mmap = get_map_shm(&global_apps);
+	if (!global_apps.wait_shm_mmap) {
+		WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
+		global_apps.allowed = 0;
+		ret = -EIO;
+		goto error;
+	}
+
+	global_apps.allowed = 1;
+	lttng_pthread_getname_np(global_apps.procname, LTTNG_UST_ABI_PROCNAME_LEN);
+error:
+	return ret;
+}
 static
 int setup_local_apps(void)
 {
+	int ret = 0;
 	const char *home_dir;
 	uid_t uid;
 
+	assert(!local_apps.wait_shm_mmap);
+
 	uid = getuid();
 	/*
 	 * Disallow per-user tracing for setuid binaries.
 	 */
 	if (uid != geteuid()) {
 		assert(local_apps.allowed == 0);
-		return 0;
+		ret = 0;
+		goto end;
 	}
 	home_dir = get_lttng_home_dir();
 	if (!home_dir) {
 		WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
 		assert(local_apps.allowed == 0);
-		return -ENOENT;
+		ret = -ENOENT;
+		goto end;
 	}
 	local_apps.allowed = 1;
 	snprintf(local_apps.sock_path, PATH_MAX, "%s/%s/%s",
@@ -457,7 +537,18 @@ int setup_local_apps(void)
 	snprintf(local_apps.wait_shm_path, PATH_MAX, "/%s-%u",
 		LTTNG_UST_WAIT_FILENAME,
 		uid);
-	return 0;
+
+	local_apps.wait_shm_mmap = get_map_shm(&local_apps);
+	if (!local_apps.wait_shm_mmap) {
+		WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
+		local_apps.allowed = 0;
+		ret = -EIO;
+		goto end;
+	}
+
+	lttng_pthread_getname_np(local_apps.procname, LTTNG_UST_ABI_PROCNAME_LEN);
+end:
+	return ret;
 }
 
 /*
@@ -470,7 +561,7 @@ long get_timeout(void)
 	long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS;
 
 	if (!got_timeout_env) {
-		str_timeout = getenv("LTTNG_UST_REGISTER_TIMEOUT");
+		str_timeout = lttng_getenv("LTTNG_UST_REGISTER_TIMEOUT");
 		got_timeout_env = 1;
 	}
 	if (str_timeout)
@@ -533,6 +624,19 @@ int get_constructor_timeout(struct timespec *constructor_timeout)
 	return 1;
 }
 
+static
+void get_allow_blocking(void)
+{
+	const char *str_allow_blocking =
+		lttng_getenv("LTTNG_UST_ALLOW_BLOCKING");
+
+	if (str_allow_blocking) {
+		DBG("%s environment variable is set",
+			"LTTNG_UST_ALLOW_BLOCKING");
+		lttng_ust_ringbuffer_set_allow_blocking();
+	}
+}
+
 static
 int register_to_sessiond(int socket, enum ustctl_socket_type type)
 {
@@ -569,48 +673,213 @@ int send_reply(int sock, struct ustcomm_ust_reply *lur)
 }
 
 static
-int handle_register_done(struct sock_info *sock_info)
+void decrement_sem_count(unsigned int count)
 {
 	int ret;
 
-	if (sock_info->constructor_sem_posted)
-		return 0;
-	sock_info->constructor_sem_posted = 1;
+	assert(uatomic_read(&sem_count) >= count);
+
 	if (uatomic_read(&sem_count) <= 0) {
-		return 0;
+		return;
 	}
-	ret = uatomic_add_return(&sem_count, -1);
+
+	ret = uatomic_add_return(&sem_count, -count);
 	if (ret == 0) {
 		ret = sem_post(&constructor_wait);
 		assert(!ret);
 	}
+}
+
+static
+int handle_register_done(struct sock_info *sock_info)
+{
+	if (sock_info->registration_done)
+		return 0;
+	sock_info->registration_done = 1;
+
+	decrement_sem_count(1);
+	if (!sock_info->statedump_pending) {
+		sock_info->initial_statedump_done = 1;
+		decrement_sem_count(1);
+	}
+
+	return 0;
+}
+
+static
+int handle_register_failed(struct sock_info *sock_info)
+{
+	if (sock_info->registration_done)
+		return 0;
+	sock_info->registration_done = 1;
+	sock_info->initial_statedump_done = 1;
+
+	decrement_sem_count(2);
+
 	return 0;
 }
 
 /*
  * Only execute pending statedump after the constructor semaphore has
- * been posted by each listener thread. This means statedump will only
- * be performed after the "registration done" command is received from
- * each session daemon the application is connected to.
+ * been posted by the current listener thread. This means statedump will
+ * only be performed after the "registration done" command is received
+ * from this thread's session daemon.
  *
  * This ensures we don't run into deadlock issues with the dynamic
  * loader mutex, which is held while the constructor is called and
  * waiting on the constructor semaphore. All operations requiring this
  * dynamic loader lock need to be postponed using this mechanism.
+ *
+ * In a scenario with two session daemons connected to the application,
+ * it is possible that the first listener thread which receives the
+ * registration done command issues its statedump while the dynamic
+ * loader lock is still held by the application constructor waiting on
+ * the semaphore. It will however be allowed to proceed when the
+ * second session daemon sends the registration done command to the
+ * second listener thread. This situation therefore does not produce
+ * a deadlock.
  */
 static
 void handle_pending_statedump(struct sock_info *sock_info)
 {
-	int ctor_passed = sock_info->constructor_sem_posted;
-
-	if (ctor_passed && sock_info->statedump_pending) {
+	if (sock_info->registration_done && sock_info->statedump_pending) {
 		sock_info->statedump_pending = 0;
 		pthread_mutex_lock(&ust_fork_mutex);
 		lttng_handle_pending_statedump(sock_info);
 		pthread_mutex_unlock(&ust_fork_mutex);
+
+		if (!sock_info->initial_statedump_done) {
+			sock_info->initial_statedump_done = 1;
+			decrement_sem_count(1);
+		}
+	}
+}
+
+static inline
+const char *bytecode_type_str(uint32_t cmd)
+{
+	switch (cmd) {
+	case LTTNG_UST_CAPTURE:
+		return "capture";
+	case LTTNG_UST_FILTER:
+		return "filter";
+	default:
+		abort();
 	}
 }
 
+static
+int handle_bytecode_recv(struct sock_info *sock_info,
+		int sock, struct ustcomm_ust_msg *lum)
+{
+	struct lttng_ust_bytecode_node *bytecode;
+	enum lttng_ust_bytecode_node_type type;
+	const struct lttng_ust_objd_ops *ops;
+	uint32_t data_size, data_size_max, reloc_offset;
+	uint64_t seqnum;
+	ssize_t len;
+	int ret = 0;
+
+	switch (lum->cmd) {
+	case LTTNG_UST_FILTER:
+		type = LTTNG_UST_BYTECODE_NODE_TYPE_FILTER;
+		data_size = lum->u.filter.data_size;
+		data_size_max = FILTER_BYTECODE_MAX_LEN;
+		reloc_offset = lum->u.filter.reloc_offset;
+		seqnum = lum->u.filter.seqnum;
+		break;
+	case LTTNG_UST_CAPTURE:
+		type = LTTNG_UST_BYTECODE_NODE_TYPE_CAPTURE;
+		data_size = lum->u.capture.data_size;
+		data_size_max = CAPTURE_BYTECODE_MAX_LEN;
+		reloc_offset = lum->u.capture.reloc_offset;
+		seqnum = lum->u.capture.seqnum;
+		break;
+	default:
+		abort();
+	}
+
+	if (data_size > data_size_max) {
+		ERR("Bytecode %s data size is too large: %u bytes",
+				bytecode_type_str(lum->cmd), data_size);
+		ret = -EINVAL;
+		goto end;
+	}
+
+	if (reloc_offset > data_size) {
+		ERR("Bytecode %s reloc offset %u is not within data",
+				bytecode_type_str(lum->cmd), reloc_offset);
+		ret = -EINVAL;
+		goto end;
+	}
+
+	/* Allocate the structure AND the `data[]` field. */
+	bytecode = zmalloc(sizeof(*bytecode) + data_size);
+	if (!bytecode) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	bytecode->bc.len = data_size;
+	bytecode->bc.reloc_offset = reloc_offset;
+	bytecode->bc.seqnum = seqnum;
+	bytecode->type = type;
+
+	len = ustcomm_recv_unix_sock(sock, bytecode->bc.data, bytecode->bc.len);
+	switch (len) {
+	case 0:	/* orderly shutdown */
+		ret = 0;
+		goto error_free_bytecode;
+	default:
+		if (len == bytecode->bc.len) {
+			DBG("Bytecode %s data received",
+					bytecode_type_str(lum->cmd));
+			break;
+		} else if (len < 0) {
+			DBG("Receive failed from lttng-sessiond with errno %d",
+					(int) -len);
+			if (len == -ECONNRESET) {
+				ERR("%s remote end closed connection",
+						sock_info->name);
+				ret = len;
+				goto error_free_bytecode;
+			}
+			ret = len;
+			goto error_free_bytecode;
+		} else {
+			DBG("Incorrect %s bytecode data message size: %zd",
+					bytecode_type_str(lum->cmd), len);
+			ret = -EINVAL;
+			goto error_free_bytecode;
+		}
+	}
+
+	ops = objd_ops(lum->handle);
+	if (!ops) {
+		ret = -ENOENT;
+		goto error_free_bytecode;
+	}
+
+	if (ops->cmd) {
+		ret = ops->cmd(lum->handle, lum->cmd,
+			(unsigned long) bytecode,
+			NULL, sock_info);
+		if (ret)
+			goto error_free_bytecode;
+		/* don't free bytecode if everything went fine. */
+	} else {
+		ret = -ENOSYS;
+		goto error_free_bytecode;
+	}
+
+	goto end;
+
+error_free_bytecode:
+	free(bytecode);
+end:
+	return ret;
+}
+
 static
 int handle_message(struct sock_info *sock_info,
 		int sock, struct ustcomm_ust_msg *lum)
@@ -648,76 +917,12 @@ int handle_message(struct sock_info *sock_info,
 		else
 			ret = lttng_ust_objd_unref(lum->handle, 1);
 		break;
+	case LTTNG_UST_CAPTURE:
 	case LTTNG_UST_FILTER:
-	{
-		/* Receive filter data */
-		struct lttng_ust_filter_bytecode_node *bytecode;
-
-		if (lum->u.filter.data_size > FILTER_BYTECODE_MAX_LEN) {
-			ERR("Filter data size is too large: %u bytes",
-				lum->u.filter.data_size);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		if (lum->u.filter.reloc_offset > lum->u.filter.data_size) {
-			ERR("Filter reloc offset %u is not within data",
-				lum->u.filter.reloc_offset);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		bytecode = zmalloc(sizeof(*bytecode) + lum->u.filter.data_size);
-		if (!bytecode) {
-			ret = -ENOMEM;
-			goto error;
-		}
-		len = ustcomm_recv_unix_sock(sock, bytecode->bc.data,
-				lum->u.filter.data_size);
-		switch (len) {
-		case 0:	/* orderly shutdown */
-			ret = 0;
-			free(bytecode);
+		ret = handle_bytecode_recv(sock_info, sock, lum);
+		if (ret)
 			goto error;
-		default:
-			if (len == lum->u.filter.data_size) {
-				DBG("filter data received");
-				break;
-			} else if (len < 0) {
-				DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
-				if (len == -ECONNRESET) {
-					ERR("%s remote end closed connection", sock_info->name);
-					ret = len;
-					free(bytecode);
-					goto error;
-				}
-				ret = len;
-				free(bytecode);
-				goto error;
-			} else {
-				DBG("incorrect filter data message size: %zd", len);
-				ret = -EINVAL;
-				free(bytecode);
-				goto error;
-			}
-		}
-		bytecode->bc.len = lum->u.filter.data_size;
-		bytecode->bc.reloc_offset = lum->u.filter.reloc_offset;
-		bytecode->bc.seqnum = lum->u.filter.seqnum;
-		if (ops->cmd) {
-			ret = ops->cmd(lum->handle, lum->cmd,
-					(unsigned long) bytecode,
-					&args, sock_info);
-			if (ret) {
-				free(bytecode);
-			}
-			/* don't free bytecode if everything went fine. */
-		} else {
-			ret = -ENOSYS;
-			free(bytecode);
-		}
 		break;
-	}
 	case LTTNG_UST_EXCLUSION:
 	{
 		/* Receive exclusion names */
@@ -780,6 +985,47 @@ int handle_message(struct sock_info *sock_info,
 		}
 		break;
 	}
+	case LTTNG_UST_EVENT_NOTIFIER_GROUP_CREATE:
+	{
+		int event_notifier_notif_fd;
+
+		len = ustcomm_recv_event_notifier_notif_fd_from_sessiond(sock,
+			&event_notifier_notif_fd);
+		switch (len) {
+		case 0:	/* orderly shutdown */
+			ret = 0;
+			goto error;
+		case 1:
+			break;
+		default:
+			if (len < 0) {
+				DBG("Receive failed from lttng-sessiond with errno %d",
+						(int) -len);
+				if (len == -ECONNRESET) {
+					ERR("%s remote end closed connection",
+							sock_info->name);
+					ret = len;
+					goto error;
+				}
+				ret = len;
+				goto error;
+			} else {
+				DBG("Incorrect event notifier fd message size: %zd",
+						len);
+				ret = -EINVAL;
+				goto error;
+			}
+		}
+		args.event_notifier_handle.event_notifier_notif_fd =
+				event_notifier_notif_fd;
+		if (ops->cmd)
+			ret = ops->cmd(lum->handle, lum->cmd,
+					(unsigned long) &lum->u,
+					&args, sock_info);
+		else
+			ret = -ENOSYS;
+		break;
+	}
 	case LTTNG_UST_CHANNEL:
 	{
 		void *chan_data;
@@ -819,18 +1065,30 @@ int handle_message(struct sock_info *sock_info,
 					&args, sock_info);
 		else
 			ret = -ENOSYS;
+		if (args.channel.wakeup_fd >= 0) {
+			int close_ret;
+
+			lttng_ust_lock_fd_tracker();
+			close_ret = close(args.channel.wakeup_fd);
+			lttng_ust_unlock_fd_tracker();
+			args.channel.wakeup_fd = -1;
+			if (close_ret)
+				PERROR("close");
+		}
+		free(args.channel.chan_data);
 		break;
 	}
 	case LTTNG_UST_STREAM:
 	{
 		/* Receive shm_fd, wakeup_fd */
 		ret = ustcomm_recv_stream_from_sessiond(sock,
-			&lum->u.stream.len,
+			NULL,
 			&args.stream.shm_fd,
 			&args.stream.wakeup_fd);
 		if (ret) {
 			goto error;
 		}
+
 		if (ops->cmd)
 			ret = ops->cmd(lum->handle, lum->cmd,
 					(unsigned long) &lum->u,
@@ -897,6 +1155,121 @@ int handle_message(struct sock_info *sock_info,
 			ret = -ENOSYS;
 		}
 		break;
+	case LTTNG_UST_COUNTER:
+	{
+		void *counter_data;
+
+		len = ustcomm_recv_counter_from_sessiond(sock,
+				&counter_data, lum->u.counter.len);
+		switch (len) {
+		case 0:	/* orderly shutdown */
+			ret = 0;
+			goto error;
+		default:
+			if (len == lum->u.counter.len) {
+				DBG("counter data received");
+				break;
+			} else if (len < 0) {
+				DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
+				if (len == -ECONNRESET) {
+					ERR("%s remote end closed connection", sock_info->name);
+					ret = len;
+					goto error;
+				}
+				ret = len;
+				goto error;
+			} else {
+				DBG("incorrect counter data message size: %zd", len);
+				ret = -EINVAL;
+				goto error;
+			}
+		}
+		args.counter.counter_data = counter_data;
+		if (ops->cmd)
+			ret = ops->cmd(lum->handle, lum->cmd,
+					(unsigned long) &lum->u,
+					&args, sock_info);
+		else
+			ret = -ENOSYS;
+		break;
+	}
+	case LTTNG_UST_COUNTER_GLOBAL:
+	{
+		/* Receive shm_fd */
+		ret = ustcomm_recv_counter_shm_from_sessiond(sock,
+			&args.counter_shm.shm_fd);
+		if (ret) {
+			goto error;
+		}
+
+		if (ops->cmd)
+			ret = ops->cmd(lum->handle, lum->cmd,
+					(unsigned long) &lum->u,
+					&args, sock_info);
+		else
+			ret = -ENOSYS;
+		break;
+	}
+	case LTTNG_UST_COUNTER_CPU:
+	{
+		/* Receive shm_fd */
+		ret = ustcomm_recv_counter_shm_from_sessiond(sock,
+			&args.counter_shm.shm_fd);
+		if (ret) {
+			goto error;
+		}
+
+		if (ops->cmd)
+			ret = ops->cmd(lum->handle, lum->cmd,
+					(unsigned long) &lum->u,
+					&args, sock_info);
+		else
+			ret = -ENOSYS;
+		break;
+	}
+	case LTTNG_UST_EVENT_NOTIFIER_CREATE:
+	{
+		/* Receive struct lttng_ust_event_notifier */
+		struct lttng_ust_event_notifier event_notifier;
+
+		if (sizeof(event_notifier) != lum->u.event_notifier.len) {
+			DBG("incorrect event notifier data message size: %u", lum->u.event_notifier.len);
+			ret = -EINVAL;
+			goto error;
+		}
+		len = ustcomm_recv_unix_sock(sock, &event_notifier, sizeof(event_notifier));
+		switch (len) {
+		case 0:	/* orderly shutdown */
+			ret = 0;
+			goto error;
+		default:
+			if (len == sizeof(event_notifier)) {
+				DBG("event notifier data received");
+				break;
+			} else if (len < 0) {
+				DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
+				if (len == -ECONNRESET) {
+					ERR("%s remote end closed connection", sock_info->name);
+					ret = len;
+					goto error;
+				}
+				ret = len;
+				goto error;
+			} else {
+				DBG("incorrect event notifier data message size: %zd", len);
+				ret = -EINVAL;
+				goto error;
+			}
+		}
+		if (ops->cmd)
+			ret = ops->cmd(lum->handle, lum->cmd,
+					(unsigned long) &event_notifier,
+					&args, sock_info);
+		else
+			ret = -ENOSYS;
+		break;
+	}
+
 	default:
 		if (ops->cmd)
 			ret = ops->cmd(lum->handle, lum->cmd,
@@ -1016,7 +1389,8 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
 		}
 		sock_info->root_handle = -1;
 	}
-	sock_info->constructor_sem_posted = 0;
+	sock_info->registration_done = 0;
+	sock_info->initial_statedump_done = 0;
 
 	/*
 	 * wait_shm_mmap, socket and notify socket are used by listener
@@ -1045,7 +1419,7 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
 	if (sock_info->wait_shm_mmap) {
 		long page_size;
 
-		page_size = sysconf(_SC_PAGE_SIZE);
+		page_size = LTTNG_UST_PAGE_SIZE;
 		if (page_size <= 0) {
 			if (!page_size) {
 				errno = EINVAL;
@@ -1247,7 +1621,18 @@ char *get_map_shm(struct sock_info *sock_info)
 		lttng_ust_unlock_fd_tracker();
 		goto error;
 	}
-	lttng_ust_add_fd_to_tracker(wait_shm_fd);
+
+	ret = lttng_ust_add_fd_to_tracker(wait_shm_fd);
+	if (ret < 0) {
+		ret = close(wait_shm_fd);
+		if (!ret) {
+			PERROR("Error closing fd");
+		}
+		lttng_ust_unlock_fd_tracker();
+		goto error;
+	}
+
+	wait_shm_fd = ret;
 	lttng_ust_unlock_fd_tracker();
 
 	wait_shm_mmap = mmap(NULL, page_size, PROT_READ,
@@ -1276,25 +1661,23 @@ error:
 static
 void wait_for_sessiond(struct sock_info *sock_info)
 {
+	/* Use ust_lock to check if we should quit. */
 	if (ust_lock()) {
 		goto quit;
 	}
 	if (wait_poll_fallback) {
 		goto error;
 	}
-	if (!sock_info->wait_shm_mmap) {
-		sock_info->wait_shm_mmap = get_map_shm(sock_info);
-		if (!sock_info->wait_shm_mmap)
-			goto error;
-	}
 	ust_unlock();
 
+	assert(sock_info->wait_shm_mmap);
+
 	DBG("Waiting for %s apps sessiond", sock_info->name);
 	/* Wait for futex wakeup */
 	if (uatomic_read((int32_t *) sock_info->wait_shm_mmap))
 		goto end_wait;
 
-	while (futex_async((int32_t *) sock_info->wait_shm_mmap,
+	while (lttng_ust_futex_async((int32_t *) sock_info->wait_shm_mmap,
 			FUTEX_WAIT, 0, NULL, NULL, 0)) {
 		switch (errno) {
 		case EWOULDBLOCK:
@@ -1339,7 +1722,7 @@ static
 void *ust_listener_thread(void *arg)
 {
 	struct sock_info *sock_info = arg;
-	int sock, ret, prev_connect_failed = 0, has_waited = 0;
+	int sock, ret, prev_connect_failed = 0, has_waited = 0, fd;
 	long timeout;
 
 	lttng_ust_fixup_tls();
@@ -1371,6 +1754,10 @@ restart:
 		prev_connect_failed = 0;
 	}
 
+	if (ust_lock()) {
+		goto quit;
+	}
+
 	if (sock_info->socket != -1) {
 		/* FD tracker is updated by ustcomm_close_unix_sock() */
 		ret = ustcomm_close_unix_sock(sock_info->socket);
@@ -1390,9 +1777,6 @@ restart:
 		sock_info->notify_socket = -1;
 	}
 
-	if (ust_lock()) {
-		goto quit;
-	}
 
 	/*
 	 * Register. We need to perform both connect and sending
@@ -1414,14 +1798,26 @@ restart:
 		 * If we cannot find the sessiond daemon, don't delay
 		 * constructor execution.
 		 */
-		ret = handle_register_done(sock_info);
+		ret = handle_register_failed(sock_info);
 		assert(!ret);
 		ust_unlock();
 		goto restart;
 	}
-	lttng_ust_add_fd_to_tracker(ret);
-	lttng_ust_unlock_fd_tracker();
+	fd = ret;
+	ret = lttng_ust_add_fd_to_tracker(fd);
+	if (ret < 0) {
+		ret = close(fd);
+		if (ret) {
+			PERROR("close on sock_info->socket");
+		}
+		ret = -1;
+		lttng_ust_unlock_fd_tracker();
+		ust_unlock();
+		goto quit;
+	}
+
 	sock_info->socket = ret;
+	lttng_ust_unlock_fd_tracker();
 
 	ust_unlock();
 	/*
@@ -1456,7 +1852,7 @@ restart:
 		 * If we cannot register to the sessiond daemon, don't
 		 * delay constructor execution.
 		 */
-		ret = handle_register_done(sock_info);
+		ret = handle_register_failed(sock_info);
 		assert(!ret);
 		ust_unlock();
 		goto restart;
@@ -1485,14 +1881,27 @@ restart:
 		 * If we cannot find the sessiond daemon, don't delay
 		 * constructor execution.
 		 */
-		ret = handle_register_done(sock_info);
+		ret = handle_register_failed(sock_info);
 		assert(!ret);
 		ust_unlock();
 		goto restart;
 	}
-	lttng_ust_add_fd_to_tracker(ret);
-	lttng_ust_unlock_fd_tracker();
+
+	fd = ret;
+	ret = lttng_ust_add_fd_to_tracker(fd);
+	if (ret < 0) {
+		ret = close(fd);
+		if (ret) {
+			PERROR("close on sock_info->notify_socket");
+		}
+		ret = -1;
+		lttng_ust_unlock_fd_tracker();
+		ust_unlock();
+		goto quit;
+	}
+
 	sock_info->notify_socket = ret;
+	lttng_ust_unlock_fd_tracker();
 
 	ust_unlock();
 	/*
@@ -1536,7 +1945,7 @@ restart:
 		 * If we cannot register to the sessiond daemon, don't
 		 * delay constructor execution.
 		 */
-		ret = handle_register_done(sock_info);
+		ret = handle_register_failed(sock_info);
 		assert(!ret);
 		ust_unlock();
 		goto restart;
@@ -1566,7 +1975,7 @@ restart:
 			 * If we cannot register to the sessiond daemon, don't
 			 * delay constructor execution.
 			 */
-			ret = handle_register_done(sock_info);
+			ret = handle_register_failed(sock_info);
 			assert(!ret);
 			ust_unlock();
 			goto end;
@@ -1634,6 +2043,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	pthread_attr_t thread_attr;
 	int timeout_mode;
 	int ret;
+	void *handle;
 
 	if (uatomic_xchg(&initialized, 1) == 1)
 		return;
@@ -1647,6 +2057,26 @@ void __attribute__((constructor)) lttng_ust_init(void)
 
 	lttng_ust_loaded = 1;
 
+	/*
+	 * We need to ensure that the liblttng-ust library is not unloaded to avoid
+	 * the unloading of code used by the ust_listener_threads as we can not
+	 * reliably know when they exited. To do that, manually load
+	 * liblttng-ust.so to increment the dynamic loader's internal refcount for
+	 * this library so it never becomes zero, thus never gets unloaded from the
+	 * address space of the process. Since we are already running in the
+	 * constructor of the LTTNG_UST_LIB_SO_NAME library, calling dlopen will
+	 * simply increment the refcount and no additionnal work is needed by the
+	 * dynamic loader as the shared library is already loaded in the address
+	 * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
+	 * unloading of the UST library if its refcount becomes zero (which should
+	 * never happen). Do the return value check but discard the handle at the
+	 * end of the function as it's not needed.
+	 */
+	handle = dlopen(LTTNG_UST_LIB_SO_NAME, RTLD_LAZY | RTLD_NODELETE);
+	if (!handle) {
+		ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SO_NAME);
+	}
+
 	/*
 	 * We want precise control over the order in which we construct
 	 * our sub-libraries vs starting to receive commands from
@@ -1654,6 +2084,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	 * sessiond before the init functions are completed).
 	 */
 	init_usterr();
+	lttng_ust_getenv_init();	/* Needs init_usterr() to be completed. */
 	init_tracepoint();
 	lttng_ust_init_fd_tracker();
 	lttng_ust_clock_init();
@@ -1664,6 +2095,8 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	lttng_ring_buffer_client_overwrite_rt_init();
 	lttng_ring_buffer_client_discard_init();
 	lttng_ring_buffer_client_discard_rt_init();
+	lttng_counter_client_percpu_32_modular_init();
+	lttng_counter_client_percpu_64_modular_init();
 	lttng_perf_counter_init();
 	/*
 	 * Invoke ust malloc wrapper init before starting other threads.
@@ -1672,13 +2105,22 @@ void __attribute__((constructor)) lttng_ust_init(void)
 
 	timeout_mode = get_constructor_timeout(&constructor_timeout);
 
+	get_allow_blocking();
+
 	ret = sem_init(&constructor_wait, 0, 0);
 	if (ret) {
 		PERROR("sem_init");
 	}
 
+	ret = setup_global_apps();
+	if (ret) {
+		assert(global_apps.allowed == 0);
+		DBG("global apps setup returned %d", ret);
+	}
+
 	ret = setup_local_apps();
 	if (ret) {
+		assert(local_apps.allowed == 0);
 		DBG("local apps setup returned %d", ret);
 	}
 
@@ -1702,14 +2144,18 @@ void __attribute__((constructor)) lttng_ust_init(void)
 		ERR("pthread_attr_setdetachstate: %s", strerror(ret));
 	}
 
-	pthread_mutex_lock(&ust_exit_mutex);
-	ret = pthread_create(&global_apps.ust_listener, &thread_attr,
-			ust_listener_thread, &global_apps);
-	if (ret) {
-		ERR("pthread_create global: %s", strerror(ret));
+	if (global_apps.allowed) {
+		pthread_mutex_lock(&ust_exit_mutex);
+		ret = pthread_create(&global_apps.ust_listener, &thread_attr,
+				ust_listener_thread, &global_apps);
+		if (ret) {
+			ERR("pthread_create global: %s", strerror(ret));
+		}
+		global_apps.thread_active = 1;
+		pthread_mutex_unlock(&ust_exit_mutex);
+	} else {
+		handle_register_done(&global_apps);
 	}
-	global_apps.thread_active = 1;
-	pthread_mutex_unlock(&ust_exit_mutex);
 
 	if (local_apps.allowed) {
 		pthread_mutex_lock(&ust_exit_mutex);
@@ -1780,6 +2226,7 @@ void lttng_ust_cleanup(int exiting)
 	cleanup_sock_info(&global_apps, exiting);
 	cleanup_sock_info(&local_apps, exiting);
 	local_apps.allowed = 0;
+	global_apps.allowed = 0;
 	/*
 	 * The teardown in this function all affect data structures
 	 * accessed under the UST lock by the listener thread. This
@@ -1795,11 +2242,13 @@ void lttng_ust_cleanup(int exiting)
 	lttng_ring_buffer_client_overwrite_rt_exit();
 	lttng_ring_buffer_client_overwrite_exit();
 	lttng_ring_buffer_metadata_client_exit();
+	lttng_counter_client_percpu_32_modular_exit();
+	lttng_counter_client_percpu_64_modular_exit();
 	lttng_ust_statedump_destroy();
 	exit_tracepoint();
 	if (!exiting) {
 		/* Reinitialize values for fork */
-		sem_count = 2;
+		sem_count = sem_count_initial_value;
 		lttng_ust_comm_should_quit = 0;
 		initialized = 0;
 	}
@@ -1857,6 +2306,35 @@ void __attribute__((destructor)) lttng_ust_exit(void)
 	lttng_ust_cleanup(1);
 }
 
+static
+void ust_context_ns_reset(void)
+{
+	lttng_context_pid_ns_reset();
+	lttng_context_cgroup_ns_reset();
+	lttng_context_ipc_ns_reset();
+	lttng_context_mnt_ns_reset();
+	lttng_context_net_ns_reset();
+	lttng_context_user_ns_reset();
+	lttng_context_time_ns_reset();
+	lttng_context_uts_ns_reset();
+}
+
+static
+void ust_context_vuids_reset(void)
+{
+	lttng_context_vuid_reset();
+	lttng_context_veuid_reset();
+	lttng_context_vsuid_reset();
+}
+
+static
+void ust_context_vgids_reset(void)
+{
+	lttng_context_vgid_reset();
+	lttng_context_vegid_reset();
+	lttng_context_vsgid_reset();
+}
+
 /*
  * We exclude the worker threads across fork and clone (except
  * CLONE_VM), because these system calls only keep the forking thread
@@ -1890,7 +2368,11 @@ void ust_before_fork(sigset_t *save_sigset)
 	pthread_mutex_lock(&ust_fork_mutex);
 
 	ust_lock_nocheck();
-	rcu_bp_before_fork();
+	lttng_ust_urcu_before_fork();
+	if (lttng_ust_liburcu_bp_before_fork)
+		lttng_ust_liburcu_bp_before_fork();
+	lttng_ust_lock_fd_tracker();
+	lttng_perf_lock();
 }
 
 static void ust_after_fork_common(sigset_t *restore_sigset)
@@ -1898,6 +2380,8 @@ static void ust_after_fork_common(sigset_t *restore_sigset)
 	int ret;
 
 	DBG("process %d", getpid());
+	lttng_perf_unlock();
+	lttng_ust_unlock_fd_tracker();
 	ust_unlock();
 
 	pthread_mutex_unlock(&ust_fork_mutex);
@@ -1914,7 +2398,9 @@ void ust_after_fork_parent(sigset_t *restore_sigset)
 	if (URCU_TLS(lttng_ust_nest_count))
 		return;
 	DBG("process %d", getpid());
-	rcu_bp_after_fork_parent();
+	lttng_ust_urcu_after_fork_parent();
+	if (lttng_ust_liburcu_bp_after_fork_parent)
+		lttng_ust_liburcu_bp_after_fork_parent();
 	/* Release mutexes and reenable signals */
 	ust_after_fork_common(restore_sigset);
 }
@@ -1932,16 +2418,77 @@ void ust_after_fork_child(sigset_t *restore_sigset)
 {
 	if (URCU_TLS(lttng_ust_nest_count))
 		return;
+	lttng_context_vpid_reset();
 	lttng_context_vtid_reset();
+	lttng_context_procname_reset();
+	ust_context_ns_reset();
+	ust_context_vuids_reset();
+	ust_context_vgids_reset();
 	DBG("process %d", getpid());
 	/* Release urcu mutexes */
-	rcu_bp_after_fork_child();
+	lttng_ust_urcu_after_fork_child();
+	if (lttng_ust_liburcu_bp_after_fork_child)
+		lttng_ust_liburcu_bp_after_fork_child();
 	lttng_ust_cleanup(0);
 	/* Release mutexes and reenable signals */
 	ust_after_fork_common(restore_sigset);
 	lttng_ust_init();
 }
 
+void ust_after_setns(void)
+{
+	ust_context_ns_reset();
+	ust_context_vuids_reset();
+	ust_context_vgids_reset();
+}
+
+void ust_after_unshare(void)
+{
+	ust_context_ns_reset();
+	ust_context_vuids_reset();
+	ust_context_vgids_reset();
+}
+
+void ust_after_setuid(void)
+{
+	ust_context_vuids_reset();
+}
+
+void ust_after_seteuid(void)
+{
+	ust_context_vuids_reset();
+}
+
+void ust_after_setreuid(void)
+{
+	ust_context_vuids_reset();
+}
+
+void ust_after_setresuid(void)
+{
+	ust_context_vuids_reset();
+}
+
+void ust_after_setgid(void)
+{
+	ust_context_vgids_reset();
+}
+
+void ust_after_setegid(void)
+{
+	ust_context_vgids_reset();
+}
+
+void ust_after_setregid(void)
+{
+	ust_context_vgids_reset();
+}
+
+void ust_after_setresgid(void)
+{
+	ust_context_vgids_reset();
+}
+
 void lttng_ust_sockinfo_session_enabled(void *owner)
 {
 	struct sock_info *sock_info = owner;