+/* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <getopt.h>
+#include <grp.h>
+#include <limits.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <urcu/list.h> /* URCU list library (-lurcu) */
+#include <ust/ustctl.h> /* UST control lib (-lust) */
+
+#include "liblttsessiondcomm.h"
+#include "ltt-sessiond.h"
+
+/* Static functions */
+static int set_signal_handler(void);
+static int set_socket_perms(void);
+static void sighandler(int);
+static void daemonize(void);
+static void cleanup(void);
+static int check_existing_daemon(void);
+static int notify_apps(const char*);
+static int connect_app(pid_t);
+static int init_daemon_socket(void);
+static struct lttcomm_lttng_msg *process_client_msg(struct lttcomm_session_msg*);
+
+static void *thread_manage_clients(void *);
+static void *thread_manage_apps(void *);
+
+static int create_session(const char*, uuid_t *);
+static void destroy_session(uuid_t);
+
+static struct ltt_session *find_session(uuid_t);
+
+/* Variables */
+const char *progname;
+const char *opt_tracing_group;
+static int opt_daemon;
+static int is_root; /* Set to 1 if the daemon is running as root */
+
+static char apps_unix_sock_path[PATH_MAX]; /* Global application Unix socket path */
+static char client_unix_sock_path[PATH_MAX]; /* Global client Unix socket path */
+
+static int client_socket;
+static int apps_socket;
+
+static struct ltt_session *current_session;
+static int session_count;
+
+/* Init session's list */
+static struct ltt_session_list ltt_session_list = {
+ .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
+};
+
+static struct ltt_traceable_app_list ltt_traceable_app_list = {
+ .head = CDS_LIST_HEAD_INIT(ltt_traceable_app_list.head),
+};
+
+/*
+ * thread_manage_apps
+ *
+ * This thread manage the application socket communication
+ */
+static void *thread_manage_apps(void *data)
+{
+ int sock, ret;
+ struct ltt_traceable_app *lta;
+
+ /* TODO: Something more elegant is needed but fine for now */
+ struct {
+ int reg; /* 1:register, 0:unregister */
+ pid_t pid;
+ uid_t uid;
+ } reg_msg;
+
+ /* Notify all applications to register */
+ notify_apps(default_global_apps_pipe);
+
+ ret = lttcomm_listen_unix_sock(apps_socket);
+ if (ret < 0) {
+ goto error;
+ }
+
+ while (1) {
+ /* Blocking call, waiting for transmission */
+ sock = lttcomm_accept_unix_sock(apps_socket);
+ if (sock < 0) {
+ goto error;
+ }
+
+ /* Basic recv here to handle the very simple data
+ * that the libust send to register (reg_msg).
+ */
+ ret = recv(sock, ®_msg, sizeof(reg_msg), 0);
+ if (ret < 0) {
+ perror("recv");
+ continue;
+ }
+
+ /* Add application to the global traceable list */
+ if (reg_msg.reg == 1) {
+ /* Registering */
+ lta = malloc(sizeof(struct ltt_traceable_app));
+ lta->pid = reg_msg.pid;
+ lta->uid = reg_msg.uid;
+ cds_list_add(<a->list, <t_traceable_app_list.head);
+ } else {
+ /* Unregistering */
+ lta = NULL;
+ cds_list_for_each_entry(lta, <t_traceable_app_list.head, list) {
+ if (lta->pid == reg_msg.pid && lta->uid == reg_msg.uid) {
+ cds_list_del(<a->list);
+ break;
+ }
+ }
+
+ /* If an item was found, free it from memory */
+ if (lta) {
+ free(lta);
+ }
+ }
+ }
+
+error:
+
+ return NULL;
+}
+
+/*
+ * thread_manage_clients
+ *
+ * This thread manage all clients request using the unix
+ * client socket for communication.
+ */
+static void *thread_manage_clients(void *data)
+{
+ int sock, ret;
+ struct lttcomm_session_msg lsm;
+ struct lttcomm_lttng_msg *llm;
+
+ ret = lttcomm_listen_unix_sock(client_socket);
+ if (ret < 0) {
+ goto error;
+ }
+
+ while (1) {
+ /* Blocking call, waiting for transmission */
+ sock = lttcomm_accept_unix_sock(client_socket);
+ if (sock < 0) {
+ goto error;
+ }
+
+ /*
+ * Data is received from the lttng client. The struct
+ * lttcomm_session_msg (lsm) contains the command and data
+ * request of the client.
+ */
+ ret = lttcomm_recv_unix_sock(sock, &lsm, sizeof(lsm));
+ if (ret < 0) {
+ continue;
+ }
+
+ /* This function dispatch the work to the LTTng or UST libs
+ * and make sure that the reply structure (llm) is filled.
+ */
+ llm = process_client_msg(&lsm);
+
+ /* Having a valid lttcomm_lttng_msg struct, reply is sent back
+ * to the client directly.
+ */
+ if (llm != NULL) {
+ ret = lttcomm_send_unix_sock(sock, llm,
+ sizeof(struct lttcomm_lttng_msg));
+ free(llm);
+ if (ret < 0) {
+ continue;
+ }
+ } else {
+ /* The lttcomm_lttng_msg struct was not allocated
+ * correctly. Fatal error since the daemon is not able
+ * to respond. However, we still permit client connection.
+ *
+ * TODO: We should have a default llm that tells the client
+ * that the sessiond had a fatal error and thus the client could
+ * take action to restart ltt-sessiond or inform someone.
+ */
+ }
+ }
+
+error:
+ return NULL;
+}
+
+/*
+ * connect_app
+ *
+ * Return a socket connected to the libust communication socket
+ * of the application identified by the pid.
+ */
+static int connect_app(pid_t pid)
+{
+ int sock;
+
+ sock = ustctl_connect_pid(pid);
+ if (sock < 0) {
+ fprintf(stderr, "Fail connecting to the PID %d\n", pid);
+ }
+
+ return sock;
+}
+
+/*
+ * notify_apps
+ *
+ * Notify apps by writing 42 to a named pipe using name.
+ * Every applications waiting for a ltt-sessiond will be notified
+ * and re-register automatically to the session daemon.
+ *
+ * Return open or write error value.
+ */
+static int notify_apps(const char *name)
+{
+ int fd;
+ int ret = -1;
+
+ /* Try opening the global pipe */
+ fd = open(name, O_WRONLY);
+ if (fd < 0) {
+ goto error;
+ }
+
+ /* Notify by writing on the pipe */
+ ret = write(fd, "42", 2);
+ if (ret < 0) {
+ perror("write");
+ }
+
+error:
+ return ret;
+}
+
+/*
+ * find_session
+ *
+ * Return a ltt_session structure ptr that matches the uuid.
+ */
+static struct ltt_session *find_session(uuid_t session_id)
+{
+ struct ltt_session *iter = NULL;
+
+ /* Sanity check for NULL session_id */
+ if (uuid_is_null(session_id)) {
+ goto end;
+ }
+
+ cds_list_for_each_entry(iter, <t_session_list.head, list) {
+ if (uuid_compare(iter->uuid, session_id)) {
+ break;
+ }
+ }
+
+end:
+ return iter;
+}
+
+/*
+ * destroy_session
+ *
+ * Delete session from the global session list
+ * and free the memory.
+ */
+static void destroy_session(uuid_t session_id)
+{
+ struct ltt_session *iter = NULL;
+
+ cds_list_for_each_entry(iter, <t_session_list.head, list) {
+ if (uuid_compare(iter->uuid, session_id)) {
+ cds_list_del(&iter->list);
+ break;
+ }
+ }
+
+ if (iter) {
+ free(iter);
+ session_count--;
+ }
+}
+
+/*
+ * create_session
+ *
+ * Create a brand new session,
+ */
+static int create_session(const char *name, uuid_t *session_id)
+{
+ struct ltt_session *new_session;
+
+ /* Allocate session data structure */
+ new_session = malloc(sizeof(struct ltt_session));
+ if (new_session == NULL) {
+ perror("malloc");
+ goto error;
+ }
+
+ if (name != NULL) {
+ if (asprintf(&new_session->name, "%s", name) < 0) {
+ goto error;
+ }
+ } else {
+ /* Generate session name based on the session count */
+ if (asprintf(&new_session->name, "%s%d", "auto", session_count) < 0) {
+ goto error;
+ }
+ }
+
+ /* UUID generation */
+ uuid_generate(new_session->uuid);
+ uuid_copy(*session_id, new_session->uuid);
+
+ /* Set consumer (identifier) to 0. This means that there is
+ * NO consumer attach to that session yet.
+ */
+ new_session->ust_consumer = 0;
+ new_session->lttng_consumer = 0;
+
+ /* Init list */
+ CDS_INIT_LIST_HEAD(&new_session->ust_traces);
+ CDS_INIT_LIST_HEAD(&new_session->lttng_traces);
+
+ /* Add new session to the global session list */
+ cds_list_add(&new_session->list, <t_session_list.head);
+
+ session_count++;
+
+ return 0;
+
+error:
+ return -1;
+}
+
+/*
+ * ust_list_apps
+ *
+ * List traceable user-space application and fill an
+ * array of pids.
+ *
+ * Return size of the array.
+ */
+static size_t ust_list_apps(pid_t *pids)
+{
+ size_t size = 0;
+ struct ltt_traceable_app *iter = NULL;
+
+ cds_list_for_each_entry(iter, <t_traceable_app_list.head, list) {
+ if (size >= MAX_APPS_PID) {
+ break;
+ }
+
+ pids[size] = iter->pid;
+ size++;
+ }
+
+ return size;
+}
+
+/*
+ * process_client_msg
+ *
+ * This takes the lttcomm_session_msg struct and process the command requested
+ * by the client. It then creates the reply by allocating a lttcomm_lttng_msg
+ * and fill it with the necessary information.
+ *
+ * It's the caller responsability to free that structure when done with it.
+ *
+ * Return pointer to lttcomm_lttng_msg allocated struct.
+ */
+static struct lttcomm_lttng_msg *process_client_msg(struct lttcomm_session_msg *lsm)
+{
+ struct lttcomm_lttng_msg *llm;
+
+ /* Allocate the reply message structure */
+ llm = malloc(sizeof(struct lttcomm_lttng_msg));
+ if (llm == NULL) {
+ perror("malloc");
+ goto end;
+ }
+
+ /* Copy common data to identify the response
+ * on the lttng client side.
+ */
+ llm->cmd_type = lsm->cmd_type;
+ llm->pid = lsm->pid;
+ if (!uuid_is_null(lsm->session_id)) {
+ uuid_copy(llm->session_id, lsm->session_id);
+ }
+ strncpy(llm->trace_name, lsm->trace_name, sizeof(llm->trace_name));
+
+ /* Default return code.
+ * In a our world, everything is OK... right?
+ */
+ llm->ret_code = LTTCOMM_OK;
+
+ /* Process by command type */
+ switch (lsm->cmd_type) {
+ case UST_LIST_APPS:
+ {
+ llm->u.list_apps.size = ust_list_apps(llm->u.list_apps.pids);
+ break;
+ }
+ default:
+ /* Undefined command */
+ llm->ret_code = LTTCOMM_UND;
+ break;
+ }
+
+end:
+ return llm;
+}
+
+/*
+ * usage function on stderr
+ */
+static void usage(void)
+{
+ fprintf(stderr, "Usage:\n%s OPTIONS\n\nOptions:\n"
+ "\t-h, --help\t\tDisplay this usage.\n"
+ "\t-c, --client-sock PATH\t\tSpecify path for the client unix socket\n"
+ "\t-a, --apps-sock PATH\t\tSpecify path for apps unix socket.\n"
+ "\t-d, --daemonize\t\tStart as a daemon.\n"
+ "\t-g, --group NAME\t\tSpecify the tracing group name. (default: tracing)\n"
+ "\t-V, --version\t\tShow version number.\n",
+ progname);
+}
+
+/*
+ * daemon argument parsing
+ */
+static int parse_args(int argc, char **argv)
+{
+ int c;
+
+ static struct option long_options[] = {
+ { "client-sock", 1, 0, 'c' },
+ { "apps-sock", 1, 0, 'a' },
+ { "daemonize", 0, 0, 'd' },
+ { "help", 0, 0, 'h' },
+ { "group", 1, 0, 'g' },
+ { "version", 0, 0, 'V' },
+ { NULL, 0, 0, 0 }
+ };
+
+ while (1) {
+ int option_index = 0;
+ c = getopt_long(argc, argv, "dhV" "a:c:g:s:", 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 's':
+ 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 = strdup(optarg);
+ break;
+ case 'h':
+ usage();
+ exit(EXIT_FAILURE);
+ case 'V':
+ fprintf(stdout, "%s\n", VERSION);
+ exit(EXIT_SUCCESS);
+ default:
+ /* Unknown option or other error.
+ * Error is printed by getopt, just return */
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * init_daemon_socket
+ *
+ * Creates the two needed socket by the daemon.
+ * apps_socket - The communication socket for all UST apps.
+ * client_socket - The communication of the cli tool (lttng).
+ */
+static int init_daemon_socket()
+{
+ int ret = 0;
+ mode_t old_umask;
+
+ old_umask = umask(0);
+
+ /* Create client tool unix socket */
+ client_socket = lttcomm_create_unix_sock(client_unix_sock_path);
+ if (client_socket < 0) {
+ ret = -1;
+ goto end;
+ }
+
+ /* File permission MUST be 660 */
+ ret = chmod(client_unix_sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+ if (ret < 0) {
+ perror("chmod");
+ goto end;
+ }
+
+ /* Create the application unix socket */
+ apps_socket = lttcomm_create_unix_sock(apps_unix_sock_path);
+ if (apps_socket < 0) {
+ ret = -1;
+ goto end;
+ }
+
+ /* File permission MUST be 660 */
+ ret = chmod(apps_unix_sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
+ if (ret < 0) {
+ perror("chmod");
+ goto end;
+ }
+
+end:
+ umask(old_umask);
+ return ret;
+}
+
+/*
+ * check_existing_daemon
+ *
+ * Check if the global socket is available.
+ * If yes, error is returned.
+ */
+static int check_existing_daemon()
+{
+ int ret;
+
+ ret = access(client_unix_sock_path, F_OK);
+ if (ret == 0) {
+ ret = access(apps_unix_sock_path, F_OK);
+ }
+
+ return ret;
+}
+
+/*
+ * get_home_dir
+ *
+ * Return pointer to home directory path using
+ * the env variable HOME.
+ *
+ * Default : /tmp
+ */
+static const char *get_home_dir(void)
+{
+ const char *home_path;
+
+ if ((home_path = (const char*) getenv("HOME")) == NULL) {
+ home_path = default_home_dir;
+ }
+
+ return home_path;
+}
+
+/*
+ * set_socket_perms
+ *
+ * Set the tracing group gid onto the client socket.
+ */
+static int set_socket_perms(void)
+{
+ int ret;
+ struct group *grp;
+
+ /* Decide which group name to use */
+ (opt_tracing_group != NULL) ?
+ (grp = getgrnam(opt_tracing_group)) :
+ (grp = getgrnam(default_tracing_group));
+
+ if (grp == NULL) {
+ fprintf(stderr, "Missing tracing group. Aborting execution.\n");
+ ret = -1;
+ goto end;
+ }
+
+ ret = chown(client_unix_sock_path, 0, grp->gr_gid);
+ if (ret < 0) {
+ perror("chown");
+ }
+
+end:
+ return ret;
+}
+
+/*
+ * daemonize
+ *
+ * Daemonize ltt-sessiond.
+ */
+static void daemonize(void)
+{
+ pid_t pid, sid;
+ const char *home_dir = get_home_dir();
+
+ /* Fork off the parent process */
+ if ((pid = fork()) < 0) {
+ perror("fork");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Parent can now exit */
+ if (pid > 0) {
+ exit(EXIT_SUCCESS);
+ }
+
+ /* Change the file mode mask */
+ umask(0);
+
+ /* Create a new SID for the child process */
+ if ((sid = setsid()) < 0) {
+ perror("setsid");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Change the current working directory */
+ if ((chdir(home_dir)) < 0) {
+ perror("chdir");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Close out the standard file descriptors */
+ close(STDIN_FILENO);
+ close(STDOUT_FILENO);
+ close(STDERR_FILENO);
+}
+
+/*
+ * set_signal_handler
+ *
+ * Setup signal handler for :
+ * SIGINT, SIGTERM, SIGPIPE
+ */
+static int set_signal_handler(void)
+{
+ int ret = 0;
+ struct sigaction sa;
+ sigset_t sigset;
+
+ if ((ret = sigemptyset(&sigset)) < 0) {
+ perror("sigemptyset");
+ return ret;
+ }
+
+ sa.sa_handler = sighandler;
+ sa.sa_mask = sigset;
+ sa.sa_flags = 0;
+ if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
+ perror("sigaction");
+ return ret;
+ }
+
+ if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
+ perror("sigaction");
+ return ret;
+ }
+
+ if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
+ perror("sigaction");
+ return ret;
+ }
+
+ return ret;
+}
+
+/**
+ * sighandler
+ *
+ * Signal handler for the daemon
+ */
+static void sighandler(int sig)
+{
+ switch (sig) {
+ case SIGPIPE:
+ case SIGINT:
+ case SIGTERM:
+ cleanup();
+ default:
+ break;
+ }
+
+ exit(EXIT_SUCCESS);
+}
+
+/*
+ * cleanup
+ *
+ * Cleanup the daemon on exit
+ */
+static void cleanup()
+{
+ /* <fun> */
+ fprintf(stdout, "\n\n%c[%d;%dm*** assert failed *** ==> %c[%dm", 27,1,31,27,0);
+ fprintf(stdout, "%c[%d;%dm Matthew, BEET driven development works!%c[%dm\n",27,1,33,27,0);
+ /* </fun> */
+
+ unlink(client_unix_sock_path);
+ unlink(apps_unix_sock_path);
+}
+
+/*
+ * main
+ */
+int main(int argc, char **argv)
+{
+ int i;
+ int ret = 0;
+ void *status;
+ pthread_t threads[2];
+
+ /* Parse arguments */
+ progname = argv[0];
+ if ((ret = parse_args(argc, argv) < 0)) {
+ goto error;
+ }
+
+ /* Daemonize */
+ if (opt_daemon) {
+ daemonize();
+ }
+
+ /* Check if daemon is UID = 0 */
+ is_root = !getuid();
+
+ /* Set all sockets path */
+ if (is_root) {
+ if (strlen(apps_unix_sock_path) == 0) {
+ (snprintf(apps_unix_sock_path, PATH_MAX,
+ DEFAULT_GLOBAL_APPS_UNIX_SOCK));
+ }
+
+ if (strlen(client_unix_sock_path) == 0) {
+ (snprintf(client_unix_sock_path, PATH_MAX,
+ DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
+ }
+ } else {
+ if (strlen(apps_unix_sock_path) == 0) {
+ (snprintf(apps_unix_sock_path, PATH_MAX,
+ DEFAULT_HOME_APPS_UNIX_SOCK, get_home_dir()));
+ }
+
+ /* 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, get_home_dir()));
+ }
+ }
+
+ /* See if daemon already exist. If any of the two
+ * socket needed by the daemon are present, this test fails
+ */
+ if ((ret = check_existing_daemon()) == 0) {
+ fprintf(stderr, "Already running daemon.\n");
+ goto error;
+ }
+
+ if (set_signal_handler() < 0) {
+ goto error;
+ }
+
+ /* Setup the two needed unix socket */
+ if (init_daemon_socket() < 0) {
+ goto error;
+ }
+
+ /* Set credentials to socket */
+ if (is_root && (set_socket_perms() < 0)) {
+ goto error;
+ }
+
+ while (1) {
+ /* Create thread to manage the client socket */
+ ret = pthread_create(&threads[0], NULL, thread_manage_clients, (void *) NULL);
+ if (ret != 0) {
+ perror("pthread_create");
+ goto error;
+ }
+
+ /* Create thread to manage application socket */
+ ret = pthread_create(&threads[1], NULL, thread_manage_apps, (void *) NULL);
+ if (ret != 0) {
+ perror("pthread_create");
+ goto error;
+ }
+
+ for (i = 0; i < 2; i++) {
+ ret = pthread_join(threads[i], &status);
+ if (ret != 0) {
+ perror("pthread_join");
+ goto error;
+ }
+ }
+ }
+
+ cleanup();
+ return 0;
+
+error:
+ cleanup();
+
+ return EXIT_FAILURE;
+}
projects / lttng-tools.git / commitdiff
