X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=lttng%2Flttng.c;h=095ebe5e1c898343b86d177bfd39a926115b3090;hp=62585528808125dbc3a65eb925448809ad5542fe;hb=5716705821202372fd16168f66f347ba293ef6b4;hpb=ebafd2a5241f74a15c0e563af001b8d651962392

diff --git a/lttng/lttng.c b/lttng/lttng.c
index 625855288..095ebe5e1 100644
--- a/lttng/lttng.c
+++ b/lttng/lttng.c
@@ -41,6 +41,9 @@ static char *progname;
 /* Prototypes */
 static int process_client_opt(void);
 static int process_opt_list_apps(void);
+static int process_opt_list_sessions(void);
+static void sighandler(int sig);
+static int set_signal_handler(void);
 
 /*
  *  start_client
@@ -66,6 +69,13 @@ static int process_client_opt(void)
 		}
 	}
 
+	if (opt_list_session) {
+		ret = process_opt_list_sessions();
+		if (ret < 0) {
+			goto end;
+		}
+	}
+
 	return 0;
 
 end:
@@ -73,6 +83,37 @@ end:
 	return ret;
 }
 
+/*
+ *  process_opt_list_sessions
+ *
+ *  Get the list of available sessions from
+ *  the session daemon and print it to user.
+ */
+static int process_opt_list_sessions(void)
+{
+	int ret, count, i;
+	struct lttng_session *sess;
+
+	count = lttng_list_sessions(&sess);
+	if (count < 0) {
+		ret = count;
+		goto error;
+	}
+
+	MSG("Available sessions [Name (uuid)]:");
+	for (i = 0; i < count; i++) {
+		MSG("\tName: %s (uuid: %s)", sess[i].name, sess[i].uuid);
+	}
+
+	free(sess);
+	MSG("\nTo select a session, use --session UUID.");
+
+	return 0;
+
+error:
+	return ret;
+}
+
 /*
  *  process_opt_list_apps
  *
@@ -113,25 +154,148 @@ error:
 	return ret;
 }
 
+/*
+ *  spawn_sessiond
+ *
+ *  Spawn a session daemon by forking and execv.
+ */
+static int spawn_sessiond(char *pathname)
+{
+	int ret = 0;
+	pid_t pid;
+
+	MSG("Spawning session daemon");
+	pid = fork();
+	if (pid == 0) {
+		/* Spawn session daemon and tell
+		 * it to signal us when ready.
+		 */
+		ret = execlp(pathname, "ltt-sessiond", "--sig-parent", NULL);
+		if (ret < 0) {
+			if (errno == ENOENT) {
+				ERR("No session daemon found. Use --sessiond-path.");
+			} else {
+				perror("execlp");
+			}
+			kill(getppid(), SIGTERM);
+			exit(EXIT_FAILURE);
+		}
+		exit(EXIT_SUCCESS);
+	} else if (pid > 0) {
+		/* Wait for ltt-sessiond to start */
+		pause();
+		goto end;
+	} else {
+		perror("fork");
+		ret = -1;
+		goto end;
+	}
+
+end:
+	return ret;
+}
+
 /*
  *  check_ltt_sessiond
  *
  *  Check if the session daemon is available using
- *  the liblttngctl API for the check.
+ *  the liblttngctl API for the check. If not, try to
+ *  spawn a daemon.
  */
 static int check_ltt_sessiond(void)
 {
 	int ret;
+	char *pathname = NULL;
 
 	ret = lttng_check_session_daemon();
 	if (ret < 0) {
-		ERR("No session daemon found. Aborting.");
+		/* Try command line option path */
+		if (opt_sessiond_path != NULL) {
+			ret = access(opt_sessiond_path, F_OK | X_OK);
+			if (ret < 0) {
+				ERR("No such file: %s", opt_sessiond_path);
+				goto end;
+			}
+			pathname = opt_sessiond_path;
+		} else {
+			/* Try LTTNG_SESSIOND_PATH env variable */
+			pathname = strdup(getenv(LTTNG_SESSIOND_PATH_ENV));
+		}
+
+		/* Let's rock and roll */
+		if (pathname == NULL) {
+			ret = asprintf(&pathname, "ltt-sessiond");
+			if (ret < 0) {
+				goto end;
+			}
+		}
+
+		ret = spawn_sessiond(pathname);
+		free(pathname);
+		if (ret < 0) {
+			ERR("Problem occurs when starting %s", pathname);
+			goto end;
+		}
+	}
+
+end:
+	return ret;
+}
+
+/*
+ *  set_signal_handler
+ *
+ *  Setup signal handler for SIGCHLD and SIGTERM.
+ */
+static int set_signal_handler(void)
+{
+	int ret = 0;
+	struct sigaction sa;
+	sigset_t sigset;
+
+	if ((ret = sigemptyset(&sigset)) < 0) {
+		perror("sigemptyset");
+		goto end;
 	}
 
+	sa.sa_handler = sighandler;
+	sa.sa_mask = sigset;
+	sa.sa_flags = 0;
+	if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) {
+		perror("sigaction");
+		goto end;
+	}
+
+	if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
+		perror("sigaction");
+		goto end;
+	}
+
+end:
 	return ret;
 }
 
+/*
+ *  sighandler
+ *
+ *  Signal handler for the daemon
+ */
+static void sighandler(int sig)
+{
+	DBG("%d received", sig);
+	switch (sig) {
+		case SIGTERM:
+			clean_exit(EXIT_FAILURE);
+			break;
+		case SIGCHLD:
+			/* Notify is done */
+			break;
+		default:
+			break;
+	}
 
+	return;
+}
 /*
  * clean_exit
  */
@@ -142,7 +306,7 @@ void clean_exit(int code)
 }
 
 /*
- * main
+ *  main
  */
 int main(int argc, char *argv[])
 {
@@ -160,6 +324,11 @@ int main(int argc, char *argv[])
 		return EXIT_FAILURE;
 	}
 
+	ret = set_signal_handler();
+	if (ret < 0) {
+		return ret;
+	}
+
 	if (opt_tracing_group != NULL) {
 		DBG("Set tracing group to '%s'", opt_tracing_group);
 		lttng_set_tracing_group(opt_tracing_group);
@@ -177,7 +346,7 @@ int main(int argc, char *argv[])
 	/* Check if the lttng session daemon is running.
 	 * If no, a daemon will be spawned.
 	 */
-	if (check_ltt_sessiond() < 0) {
+	if (opt_no_sessiond == 0 && (check_ltt_sessiond() < 0)) {
 		return EXIT_FAILURE;
 	}