X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng%2Fcommands%2Fcreate.c;h=0ae2b10968456adc54d4df7f4985458268c4e8f7;hp=f89e2778c78d8a3dd0bc97a5e95210389d68c2c5;hb=8d5841ea483139d3ab2f2b4dd39263dad63832b1;hpb=00e2e675d54dc726a7c8f8887c889cc8ef022003

diff --git a/src/bin/lttng/commands/create.c b/src/bin/lttng/commands/create.c
index f89e2778c..0ae2b1096 100644
--- a/src/bin/lttng/commands/create.c
+++ b/src/bin/lttng/commands/create.c
@@ -15,7 +15,9 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
+#include <assert.h>
+#include <ctype.h>
 #include <popt.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -24,6 +26,10 @@
 #include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
+#include <signal.h>
+#include <sys/wait.h>
+
+#include <common/mi-lttng.h>
 
 #include "../command.h"
 #include "../utils.h"
@@ -31,115 +37,180 @@
 #include <common/defaults.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 #include <common/uri.h>
+#include <common/utils.h>
+#include <lttng/snapshot.h>
 
 static char *opt_output_path;
 static char *opt_session_name;
-static char *opt_uris;
-static char *opt_ctrl_uris;
-static char *opt_data_uris;
-static int opt_no_consumer = 1;
+static char *opt_url;
+static char *opt_ctrl_url;
+static char *opt_data_url;
+static char *opt_shm_path;
+static int opt_no_consumer;
+static int opt_no_output;
+static int opt_snapshot;
+static unsigned int opt_live_timer;
 
 enum {
 	OPT_HELP = 1,
 	OPT_LIST_OPTIONS,
+	OPT_LIVE_TIMER,
 };
 
+static struct mi_writer *writer;
+
 static struct poptOption long_options[] = {
 	/* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
 	{"help", 'h', POPT_ARG_NONE, NULL, OPT_HELP, NULL, NULL},
 	{"output", 'o', POPT_ARG_STRING, &opt_output_path, 0, NULL, NULL},
 	{"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
-	{"set-uri",        'U', POPT_ARG_STRING, &opt_uris, 0, 0, 0},
-	{"ctrl-uri",       'C', POPT_ARG_STRING, &opt_ctrl_uris, 0, 0, 0},
-	{"data-uri",       'D', POPT_ARG_STRING, &opt_data_uris, 0, 0, 0},
-	{"no-consumer",      0, POPT_ARG_NONE, &opt_no_consumer, 0, 0, 0},
+	{"set-url",        'U', POPT_ARG_STRING, &opt_url, 0, 0, 0},
+	{"ctrl-url",       'C', POPT_ARG_STRING, &opt_ctrl_url, 0, 0, 0},
+	{"data-url",       'D', POPT_ARG_STRING, &opt_data_url, 0, 0, 0},
+	{"no-output",       0, POPT_ARG_VAL, &opt_no_output, 1, 0, 0},
+	{"no-consumer",     0, POPT_ARG_VAL, &opt_no_consumer, 1, 0, 0},
+	{"snapshot",        0, POPT_ARG_VAL, &opt_snapshot, 1, 0, 0},
+	{"live",            0, POPT_ARG_INT | POPT_ARGFLAG_OPTIONAL, 0, OPT_LIVE_TIMER, 0, 0},
+	{"shm-path",        0, POPT_ARG_STRING, &opt_shm_path, 0, 0, 0},
 	{0, 0, 0, 0, 0, 0, 0}
 };
 
 /*
- * usage
+ * Please have a look at src/lib/lttng-ctl/lttng-ctl.c for more information on
+ * why this declaration exists and used ONLY in for this command.
  */
-static void usage(FILE *ofp)
-{
-	fprintf(ofp, "usage: lttng create [options] [NAME]\n");
-	fprintf(ofp, "\n");
-	fprintf(ofp, "  The default NAME is 'auto-yyyymmdd-hhmmss'\n");
-	fprintf(ofp, "  -h, --help           Show this help\n");
-	fprintf(ofp, "      --list-options   Simple listing of options\n");
-	fprintf(ofp, "  -o, --output PATH    Specify output path for traces\n");
-	fprintf(ofp, "  -U, --set-uri=URI    Set URI for the enable-consumer destination.\n");
-	fprintf(ofp, "                       It is persistent for the session lifetime.\n");
-	fprintf(ofp, "                       Redo the command to change it.\n");
-	fprintf(ofp, "                       This will set both data and control URI for network.\n");
-	fprintf(ofp, "  -C, --ctrl-uri=URI   Set control path URI.\n");
-	fprintf(ofp, "  -D, --data-uri=URI   Set data path URI.\n");
-	fprintf(ofp, "      --no-consumer    Disable consumer for entire tracing session.\n");
-	fprintf(ofp, "\n");
-}
+extern int _lttng_create_session_ext(const char *name, const char *url,
+		const char *datetime);
 
 /*
- * Parse URI from string to lttng_uri object array.
+ * Retrieve the created session and mi output it based on provided argument
+ * This is currently a summary of what was pretty printed and is subject to
+ * enhancements.
  */
-static ssize_t parse_uri_from_str(const char *str_uri, struct lttng_uri **uris)
+static int mi_created_session(const char *session_name)
 {
-	int i;
-	ssize_t size;
-	struct lttng_uri *uri;
+	int ret, i, count, found;
+	struct lttng_session *sessions;
 
-	if (*uris != NULL) {
-		free(*uris);
+	/* session_name should not be null */
+	assert(session_name);
+	assert(writer);
+
+	count = lttng_list_sessions(&sessions);
+	if (count < 0) {
+		ret = count;
+		ERR("%s", lttng_strerror(ret));
+		goto error;
 	}
 
-	size = uri_parse(str_uri, uris);
-	if (size < 1) {
-		ERR("Bad URI %s. Either the hostname or IP is invalid", str_uri);
-		size = -1;
+	if (count == 0) {
+		ERR("Error session creation failed: session %s not found", session_name);
+		ret = -LTTNG_ERR_SESS_NOT_FOUND;
+		goto end;
 	}
 
-	for (i = 0; i < size; i++) {
-		uri = (struct lttng_uri *) &uris[i];
-		/* Set default port if none was given */
-		if (uri->port == 0) {
-			if (uri->stype == LTTNG_STREAM_CONTROL) {
-				uri->port = DEFAULT_NETWORK_CONTROL_PORT;
-			} else if (uri->stype == LTTNG_STREAM_DATA) {
-				uri->port = DEFAULT_NETWORK_DATA_PORT;
+	found = 0;
+	for (i = 0; i < count; i++) {
+		if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
+			found = 1;
+			ret = mi_lttng_session(writer, &sessions[i], 0);
+			if (ret) {
+				goto error;
 			}
+			break;
 		}
 	}
 
-	return size;
+	if (!found) {
+		ret = -LTTNG_ERR_SESS_NOT_FOUND;
+	} else {
+		ret = CMD_SUCCESS;
+	}
+
+error:
+	free(sessions);
+end:
+	return ret;
 }
 
 /*
- * Print URI message.
+ * For a session name, set the consumer URLs.
  */
-static void print_uri_msg(struct lttng_uri *uri)
+static int set_consumer_url(const char *session_name, const char *ctrl_url,
+		const char *data_url)
 {
-	char *dst;
-
-	switch (uri->dtype) {
-	case LTTNG_DST_IPV4:
-		dst = uri->dst.ipv4;
-		break;
-	case LTTNG_DST_IPV6:
-		dst = uri->dst.ipv6;
-		break;
-	case LTTNG_DST_PATH:
-		dst = uri->dst.path;
-		MSG("Consumer destination set to %s", dst);
-		goto end;
-	default:
-		DBG("Unknown URI destination");
-		goto end;
+	int ret;
+	struct lttng_handle *handle;
+
+	assert(session_name);
+
+	/*
+	 * Set handle with the session_name, but no domain. This implies that
+	 * the actions taken with this handle apply on the tracing session
+	 * rather then the domain-specific session.
+	 */
+	handle = lttng_create_handle(session_name, NULL);
+	if (handle == NULL) {
+		ret = CMD_FATAL;
+		goto error;
 	}
 
-	MSG("Consumer %s stream set to %s with the %s protocol on port %d",
-			uri->stype == LTTNG_STREAM_CONTROL ? "control" : "data",
-			dst, uri->proto == LTTNG_TCP ? "TCP" : "UNK", uri->port);
+	ret = lttng_set_consumer_url(handle, ctrl_url, data_url);
+	if (ret < 0) {
+		goto error;
+	}
 
-end:
-	return;
+	if (ctrl_url) {
+		MSG("Control URL %s set for session %s", ctrl_url, session_name);
+	}
+
+	if (data_url) {
+		MSG("Data URL %s set for session %s", data_url, session_name);
+	}
+
+error:
+	lttng_destroy_handle(handle);
+	return ret;
+}
+
+static int add_snapshot_output(const char *session_name, const char *ctrl_url,
+		const char *data_url)
+{
+	int ret;
+	struct lttng_snapshot_output *output = NULL;
+
+	assert(session_name);
+
+	output = lttng_snapshot_output_create();
+	if (!output) {
+		ret = CMD_FATAL;
+		goto error_create;
+	}
+
+	if (ctrl_url) {
+		ret = lttng_snapshot_output_set_ctrl_url(ctrl_url, output);
+		if (ret < 0) {
+			goto error;
+		}
+	}
+
+	if (data_url) {
+		ret = lttng_snapshot_output_set_data_url(data_url, output);
+		if (ret < 0) {
+			goto error;
+		}
+	}
+
+	/* This call, if successful, populates the id of the output object. */
+	ret = lttng_snapshot_add_output(session_name, output);
+	if (ret < 0) {
+		goto error;
+	}
+
+error:
+	lttng_snapshot_output_destroy(output);
+error_create:
+	return ret;
 }
 
 /*
@@ -148,15 +219,15 @@ end:
  *
  *  Returns one of the CMD_* result constants.
  */
-static int create_session()
+static int create_session(void)
 {
-	int ret, have_name = 0, i;
-	char datetime[16];
-	char *session_name, *traces_path = NULL, *alloc_path = NULL;
+	int ret;
+	char *session_name = NULL, *traces_path = NULL, *alloc_path = NULL;
+	char *alloc_url = NULL, *url = NULL, datetime[16];
+	char session_name_date[NAME_MAX + 17], *print_str_url = NULL;
 	time_t rawtime;
-	ssize_t size;
 	struct tm *timeinfo;
-	struct lttng_uri *uris = NULL, *ctrl_uri = NULL, *data_uri = NULL;
+	char shm_path[PATH_MAX] = "";
 
 	/* Get date and time for automatic session name/path */
 	time(&rawtime);
@@ -165,160 +236,225 @@ static int create_session()
 
 	/* Auto session name creation */
 	if (opt_session_name == NULL) {
-		ret = asprintf(&session_name, "auto-%s", datetime);
+		ret = snprintf(session_name_date, sizeof(session_name_date),
+				DEFAULT_SESSION_NAME "-%s", datetime);
 		if (ret < 0) {
-			perror("asprintf session name");
+			PERROR("snprintf session name");
 			goto error;
 		}
-		DBG("Auto session name set to %s", session_name);
+		session_name = session_name_date;
+		DBG("Auto session name set to %s", session_name_date);
 	} else {
+		if (strlen(opt_session_name) > NAME_MAX) {
+			ERR("Session name too long. Length must be lower or equal to %d",
+					NAME_MAX);
+			ret = LTTNG_ERR_SESSION_FAIL;
+			goto error;
+		}
+		/*
+		 * Check if the session name begins with "auto-" or is exactly "auto".
+		 * Both are reserved for the default session name. See bug #449 to
+		 * understand why we need to check both here.
+		 */
+		if ((strncmp(opt_session_name, DEFAULT_SESSION_NAME "-",
+					strlen(DEFAULT_SESSION_NAME) + 1) == 0) ||
+				(strncmp(opt_session_name, DEFAULT_SESSION_NAME,
+					strlen(DEFAULT_SESSION_NAME)) == 0 &&
+				strlen(opt_session_name) == strlen(DEFAULT_SESSION_NAME))) {
+			ERR("%s is a reserved keyword for default session(s)",
+					DEFAULT_SESSION_NAME);
+			ret = CMD_ERROR;
+			goto error;
+		}
 		session_name = opt_session_name;
-		have_name = 1;
+		ret = snprintf(session_name_date, sizeof(session_name_date),
+				"%s-%s", session_name, datetime);
+		if (ret < 0) {
+			PERROR("snprintf session name");
+			goto error;
+		}
+	}
+
+	if ((!opt_ctrl_url && opt_data_url) || (opt_ctrl_url && !opt_data_url)) {
+		ERR("You need both control and data URL.");
+		ret = CMD_ERROR;
+		goto error;
 	}
 
 	if (opt_output_path != NULL) {
-		traces_path = expand_full_path(opt_output_path);
+		traces_path = utils_expand_path(opt_output_path);
 		if (traces_path == NULL) {
 			ret = CMD_ERROR;
 			goto error;
 		}
 
-		ret = asprintf(&alloc_path, "file://%s", traces_path);
+		/* Create URL string from the local file system path */
+		ret = asprintf(&alloc_url, "file://%s", traces_path);
 		if (ret < 0) {
-			PERROR("asprintf expand path");
+			PERROR("asprintf url path");
 			ret = CMD_FATAL;
 			goto error;
 		}
+		/* URL to use in the lttng_create_session() call */
+		url = alloc_url;
+		print_str_url = traces_path;
+	} else if (opt_url) { /* Handling URL (-U opt) */
+		url = opt_url;
+		print_str_url = url;
+	} else if (opt_data_url && opt_ctrl_url) {
+		/*
+		 * With both control and data, we'll be setting the consumer URL after
+		 * session creation thus use no URL.
+		 */
+		url = NULL;
+	} else if (!opt_no_output) {
+		char *tmp_path;
 
-		ret = uri_parse(alloc_path, &ctrl_uri);
-		if (ret < 1) {
-			ret = CMD_FATAL;
-			goto error;
-		}
-	} else if (opt_uris) { /* Handling URIs (-U opt) */
-		size = parse_uri_from_str(opt_uris, &uris);
-		if (size < 1) {
-			ret = CMD_ERROR;
-			goto error;
-		} else if (size == 1 && uris[0].dtype != LTTNG_DST_PATH) {
-			ERR("Only net:// and file:// are supported. "
-					"Use -C and -D for more fine grained control");
-			ret = CMD_ERROR;
-			goto error;
-		} else if (size == 2) {
-			uris[0].stype = LTTNG_STREAM_CONTROL;
-			uris[1].stype = LTTNG_STREAM_DATA;
-
-			for (i = 0; i < size; i++) {
-				/* Set default port if none was given */
-				if (uris[i].port == 0) {
-					if (uris[i].stype == LTTNG_STREAM_CONTROL) {
-						uris[i].port = DEFAULT_NETWORK_CONTROL_PORT;
-					} else {
-						uris[i].port = DEFAULT_NETWORK_DATA_PORT;
-					}
-				}
-			}
-
-			ctrl_uri = &uris[0];
-			print_uri_msg(ctrl_uri);
-			data_uri = &uris[1];
-			print_uri_msg(data_uri);
-		} else {
-			ctrl_uri = &uris[0];
-			print_uri_msg(ctrl_uri);
-		}
-	} else if (opt_ctrl_uris || opt_data_uris) {
-		/* Setting up control URI (-C opt) */
-		if (opt_ctrl_uris) {
-			size = parse_uri_from_str(opt_ctrl_uris, &uris);
-			if (size < 1) {
-				ret = CMD_ERROR;
-				goto error;
-			}
-			ctrl_uri = &uris[0];
-			ctrl_uri->stype = LTTNG_STREAM_CONTROL;
-			/* Set default port if none specified */
-			if (ctrl_uri->port == 0) {
-				ctrl_uri->port = DEFAULT_NETWORK_CONTROL_PORT;
-			}
-			print_uri_msg(ctrl_uri);
-		}
-
-		/* Setting up data URI (-D opt) */
-		if (opt_data_uris) {
-			size = parse_uri_from_str(opt_data_uris, &uris);
-			if (size < 1) {
-				ret = CMD_ERROR;
-				goto error;
-			}
-			data_uri = &uris[0];
-			data_uri->stype = LTTNG_STREAM_DATA;
-			/* Set default port if none specified */
-			if (data_uri->port == 0) {
-				data_uri->port = DEFAULT_NETWORK_DATA_PORT;
-			}
-			print_uri_msg(data_uri);
-		}
-	} else {
 		/* Auto output path */
-		alloc_path = config_get_default_path();
-		if (alloc_path == NULL) {
+		tmp_path = utils_get_home_dir();
+		if (tmp_path == NULL) {
 			ERR("HOME path not found.\n \
 					Please specify an output path using -o, --output PATH");
 			ret = CMD_FATAL;
 			goto error;
 		}
-		alloc_path = strdup(alloc_path);
-
-		if (have_name) {
-			ret = asprintf(&traces_path, "file://%s/" DEFAULT_TRACE_DIR_NAME
-					"/%s-%s", alloc_path, session_name, datetime);
-		} else {
-			ret = asprintf(&traces_path, "file://%s/" DEFAULT_TRACE_DIR_NAME
-					"/%s", alloc_path, session_name);
+		alloc_path = strdup(tmp_path);
+		if (!alloc_path) {
+			PERROR("allocating alloc_path");
+			ret = CMD_FATAL;
+			goto error;
 		}
+		ret = asprintf(&alloc_url,
+				"file://%s/" DEFAULT_TRACE_DIR_NAME "/%s",
+				alloc_path, session_name_date);
 		if (ret < 0) {
 			PERROR("asprintf trace dir name");
 			ret = CMD_FATAL;
 			goto error;
 		}
 
-		ret = uri_parse(traces_path, &ctrl_uri);
-		if (ret < 1) {
+		url = alloc_url;
+		print_str_url = alloc_url + strlen("file://");
+	} else {
+		/* No output means --no-output or --snapshot mode. */
+		url = NULL;
+	}
+
+	/* Use default live URL if NO url is/are found. */
+	if ((opt_live_timer && !opt_url) && (opt_live_timer && !opt_data_url)) {
+		ret = asprintf(&alloc_url, "net://127.0.0.1");
+		if (ret < 0) {
+			PERROR("asprintf default live URL");
 			ret = CMD_FATAL;
 			goto error;
 		}
+		url = alloc_url;
+		print_str_url = url;
 	}
 
-	/* If there is no subdir specified and the URI are network */
-	if (strlen(ctrl_uri->subdir) == 0) {
-		if (have_name) {
-			ret = snprintf(ctrl_uri->subdir, sizeof(ctrl_uri->subdir), "%s-%s",
-					session_name, datetime);
+	if (opt_snapshot && opt_live_timer) {
+		ERR("Snapshot and live modes are mutually exclusive.");
+		ret = CMD_ERROR;
+		goto error;
+	}
+
+	if (opt_snapshot) {
+		/* No output by default. */
+		const char *snapshot_url = NULL;
+
+		if (opt_url) {
+			snapshot_url = url;
+		} else if (!opt_data_url && !opt_ctrl_url) {
+			/* This is the session path that we need to use as output. */
+			snapshot_url = url;
+		}
+		ret = lttng_create_session_snapshot(session_name, snapshot_url);
+	} else if (opt_live_timer) {
+		const char *pathname;
+
+		if (opt_relayd_path) {
+			pathname = opt_relayd_path;
 		} else {
-			ret = snprintf(ctrl_uri->subdir, sizeof(ctrl_uri->subdir), "%s",
-					session_name);
+			pathname = INSTALL_BIN_PATH "/lttng-relayd";
 		}
-		if (ret < 0) {
-			PERROR("snprintf subdir");
+		if (!opt_url && !opt_data_url && !check_relayd() &&
+				spawn_relayd(pathname, 0) < 0) {
 			goto error;
 		}
-		DBG("Subdir update to %s", ctrl_uri->subdir);
+		ret = lttng_create_session_live(session_name, url, opt_live_timer);
+	} else {
+		ret = _lttng_create_session_ext(session_name, url, datetime);
 	}
-
-	ret = lttng_create_session_uri(session_name, ctrl_uri, data_uri,
-			opt_no_consumer);
 	if (ret < 0) {
 		/* Don't set ret so lttng can interpret the sessiond error. */
 		switch (-ret) {
-		case LTTCOMM_EXIST_SESS:
+		case LTTNG_ERR_EXIST_SESS:
 			WARN("Session %s already exists", session_name);
 			break;
+		default:
+			break;
 		}
 		goto error;
 	}
 
+	if (opt_ctrl_url && opt_data_url) {
+		if (opt_snapshot) {
+			ret = add_snapshot_output(session_name, opt_ctrl_url,
+					opt_data_url);
+		} else {
+			/* Setting up control URI (-C or/and -D opt) */
+			ret = set_consumer_url(session_name, opt_ctrl_url, opt_data_url);
+		}
+		if (ret < 0) {
+			/* Destroy created session because the URL are not valid. */
+			lttng_destroy_session(session_name);
+			goto error;
+		}
+	}
+
+	if (opt_shm_path) {
+		ret = snprintf(shm_path, sizeof(shm_path),
+				"%s/%s", opt_shm_path, session_name_date);
+		if (ret < 0) {
+			PERROR("snprintf shm_path");
+			goto error;
+		}
+
+		ret = lttng_set_session_shm_path(session_name, shm_path);
+		if (ret < 0) {
+			lttng_destroy_session(session_name);
+			goto error;
+		}
+	}
+
+	MSG("Session %s created.", session_name);
+	if (print_str_url && !opt_snapshot) {
+		MSG("Traces will be written in %s", print_str_url);
+
+		if (opt_live_timer) {
+			MSG("Live timer set to %u usec", opt_live_timer);
+		}
+	} else if (opt_snapshot) {
+		if (print_str_url) {
+			MSG("Default snapshot output set to: %s", print_str_url);
+		}
+		MSG("Snapshot mode set. Every channel enabled for that session will "
+				"be set to mmap output, and default to overwrite mode.");
+	}
+	if (opt_shm_path) {
+		MSG("Session %s set to shm_path: %s.", session_name,
+			shm_path);
+	}
+
+	/* Mi output */
+	if (lttng_opt_mi) {
+		ret = mi_created_session(session_name);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto error;
+		}
+	}
+
 	/* Init lttng session config */
 	ret = config_init(session_name);
 	if (ret < 0) {
@@ -326,24 +462,146 @@ static int create_session()
 		goto error;
 	}
 
-	MSG("Session %s created.", session_name);
-	if (ctrl_uri->dtype == LTTNG_DST_PATH) {
-		MSG("Traces will be written in %s" , ctrl_uri->dst.path);
-	}
-
 	ret = CMD_SUCCESS;
 
 error:
-	if (opt_session_name == NULL) {
-		free(session_name);
+	free(alloc_url);
+	free(traces_path);
+	free(alloc_path);
+
+	if (ret < 0) {
+		ERR("%s", lttng_strerror(ret));
+	}
+	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 a session daemon");
+	pid = fork();
+	if (pid == 0) {
+		/*
+		 * Spawn session daemon in daemon mode.
+		 */
+		execlp(pathname, "lttng-sessiond",
+				"--daemonize", NULL);
+		/* execlp only returns if error happened */
+		if (errno == ENOENT) {
+			ERR("No session daemon found. Use --sessiond-path.");
+		} else {
+			PERROR("execlp");
+		}
+		kill(getppid(), SIGTERM);	/* wake parent */
+		exit(EXIT_FAILURE);
+	} else if (pid > 0) {
+		/*
+		 * In daemon mode (--daemonize), sessiond only exits when
+		 * it's ready to accept commands.
+		 */
+		for (;;) {
+			int status;
+			pid_t wait_pid_ret = waitpid(pid, &status, 0);
+
+			if (wait_pid_ret < 0) {
+				if (errno == EINTR) {
+					continue;
+				}
+				PERROR("waitpid");
+				ret = -errno;
+				goto end;
+			}
+
+			if (WIFSIGNALED(status)) {
+				ERR("Session daemon was killed by signal %d",
+						WTERMSIG(status));
+				ret = -1;
+			        goto end;
+			} else if (WIFEXITED(status)) {
+				DBG("Session daemon terminated normally (exit status: %d)",
+						WEXITSTATUS(status));
+
+				if (WEXITSTATUS(status) != 0) {
+					ERR("Session daemon terminated with an error (exit status: %d)",
+							WEXITSTATUS(status));
+					ret = -1;
+				        goto end;
+				}
+				break;
+			}
+		}
+
+		goto end;
+	} else {
+		PERROR("fork");
+		ret = -1;
+		goto end;
 	}
 
-	if (alloc_path) {
-		free(alloc_path);
+end:
+	return ret;
+}
+
+/*
+ *  launch_sessiond
+ *
+ *  Check if the session daemon is available using
+ *  the liblttngctl API for the check. If not, try to
+ *  spawn a daemon.
+ */
+static int launch_sessiond(void)
+{
+	int ret;
+	char *pathname = NULL;
+
+	ret = lttng_session_daemon_alive();
+	if (ret) {
+		/* Sessiond is alive, not an error */
+		ret = 0;
+		goto end;
 	}
 
-	if (traces_path) {
-		free(traces_path);
+	/* Try command line option path */
+	pathname = opt_sessiond_path;
+
+	/* Try LTTNG_SESSIOND_PATH env variable */
+	if (pathname == NULL) {
+		pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
+	}
+
+	/* Try with configured path */
+	if (pathname == NULL) {
+		if (CONFIG_SESSIOND_BIN[0] != '\0') {
+			pathname = CONFIG_SESSIOND_BIN;
+		}
+	}
+
+	/* Try the default path */
+	if (pathname == NULL) {
+		pathname = INSTALL_BIN_PATH "/lttng-sessiond";
+	}
+
+	DBG("Session daemon binary path: %s", pathname);
+
+	/* Check existence and permissions */
+	ret = access(pathname, F_OK | X_OK);
+	if (ret < 0) {
+		ERR("No such file or access denied: %s", pathname);
+		goto end;
+	}
+
+	ret = spawn_sessiond(pathname);
+end:
+	if (ret) {
+		ERR("Problem occurred while launching session daemon (%s)",
+				pathname);
 	}
 	return ret;
 }
@@ -355,7 +613,8 @@ error:
  */
 int cmd_create(int argc, const char **argv)
 {
-	int opt, ret = CMD_SUCCESS;
+	int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
+	char *opt_arg = NULL;
 	static poptContext pc;
 
 	pc = poptGetContext(NULL, argc, argv, long_options, 0);
@@ -364,23 +623,131 @@ int cmd_create(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
 			goto end;
+		case OPT_LIVE_TIMER:
+		{
+			unsigned long v;
+
+			errno = 0;
+			opt_arg = poptGetOptArg(pc);
+			if (!opt_arg) {
+				/* Set up default values. */
+				opt_live_timer = (uint32_t) DEFAULT_LTTNG_LIVE_TIMER;
+				DBG("Session live timer interval set to default value %d",
+						opt_live_timer);
+				break;
+			}
+
+			v = strtoul(opt_arg, NULL, 0);
+			if (errno != 0 || !isdigit(opt_arg[0])) {
+				ERR("Wrong value in --live parameter: %s", opt_arg);
+				ret = CMD_ERROR;
+				goto end;
+			}
+			if (v != (uint32_t) v) {
+				ERR("32-bit overflow in --live parameter: %s", opt_arg);
+				ret = CMD_ERROR;
+				goto end;
+			}
+			if (v == 0) {
+				ERR("Live timer interval must be greater than zero");
+				ret = CMD_ERROR;
+				goto end;
+			}
+			opt_live_timer = (uint32_t) v;
+			DBG("Session live timer interval set to %d", opt_live_timer);
+			break;
+		}
 		default:
-			usage(stderr);
 			ret = CMD_UNDEFINED;
 			goto end;
 		}
 	}
 
+	if (opt_no_consumer) {
+		MSG("The option --no-consumer is obsolete. Use --no-output now.");
+		ret = CMD_WARNING;
+		goto end;
+	}
+
+	/* Spawn a session daemon if needed */
+	if (!opt_no_sessiond) {
+		ret = launch_sessiond();
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+	}
+
+	/* MI initialization */
+	if (lttng_opt_mi) {
+		writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
+		if (!writer) {
+			ret = -LTTNG_ERR_NOMEM;
+			goto end;
+		}
+
+		/* Open command element */
+		ret = mi_lttng_writer_command_open(writer,
+				mi_lttng_element_command_create);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Open output element */
+		ret = mi_lttng_writer_open_element(writer,
+				mi_lttng_element_command_output);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+	}
 	opt_session_name = (char*) poptGetArg(pc);
 
-	ret = create_session();
+	command_ret = create_session();
+	if (command_ret) {
+		success = 0;
+	}
+
+	if (lttng_opt_mi) {
+		/* Close  output element */
+		ret = mi_lttng_writer_close_element(writer);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Success ? */
+		ret = mi_lttng_writer_write_element_bool(writer,
+				mi_lttng_element_command_success, success);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Command element close */
+		ret = mi_lttng_writer_command_close(writer);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+	}
 
 end:
+	/* Mi clean-up */
+	if (writer && mi_lttng_writer_destroy(writer)) {
+		/* Preserve original error code */
+		ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
+	}
+
+	/* Overwrite ret if an error occurred in create_session() */
+	ret = command_ret ? command_ret : ret;
+
 	poptFreeContext(pc);
 	return ret;
 }