X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Flib%2Flttng-ctl%2Flttng-ctl.c;h=9e709c1b6e4157f9072838d3fdbc8f779ed63cda;hp=7df8d6de7d2dae5f3da1c299fab160ec76d6808a;hb=e848d36d1b0e7cbe1800e195fb00eaff6bce4d5e;hpb=15e376636cbda79bdd8a71d0a1bec892d9997738

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index 7df8d6de7..9e709c1b6 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -43,6 +43,9 @@
 #include <lttng/channel-internal.h>
 #include <lttng/event-internal.h>
 #include <lttng/userspace-probe-internal.h>
+#include <lttng/session-internal.h>
+#include <lttng/session-descriptor-internal.h>
+#include <lttng/destruction-handle.h>
 
 #include "filter/filter-ast.h"
 #include "filter/filter-parser.h"
@@ -66,7 +69,7 @@ do {								\
 
 
 /* Socket to session daemon for communication */
-static int sessiond_socket;
+static int sessiond_socket = -1;
 static char sessiond_sock_path[PATH_MAX];
 
 /* Variables */
@@ -241,15 +244,13 @@ end:
 LTTNG_HIDDEN
 int lttng_check_tracing_group(void)
 {
-	struct group *grp_tracing;	/* no free(). See getgrnam(3) */
-	gid_t *grp_list;
+	gid_t *grp_list, tracing_gid;
 	int grp_list_size, grp_id, i;
 	int ret = -1;
 	const char *grp_name = tracing_group;
 
 	/* Get GID of group 'tracing' */
-	grp_tracing = getgrnam(grp_name);
-	if (!grp_tracing) {
+	if (utils_get_group_id(grp_name, false, &tracing_gid)) {
 		/* If grp_tracing is NULL, the group does not exist. */
 		goto end;
 	}
@@ -274,7 +275,7 @@ int lttng_check_tracing_group(void)
 	}
 
 	for (i = 0; i < grp_list_size; i++) {
-		if (grp_list[i] == grp_tracing->gr_gid) {
+		if (grp_list[i] == tracing_gid) {
 			ret = 1;
 			break;
 		}
@@ -287,6 +288,50 @@ end:
 	return ret;
 }
 
+static int check_enough_available_memory(size_t num_bytes_requested_per_cpu)
+{
+	int ret;
+	long num_cpu;
+	size_t best_mem_info;
+	size_t num_bytes_requested_total;
+
+	/*
+	 * Get the number of CPU currently online to compute the amount of
+	 * memory needed to create a buffer for every CPU.
+	 */
+	num_cpu = sysconf(_SC_NPROCESSORS_ONLN);
+	if (num_cpu == -1) {
+		goto error;
+	}
+
+	num_bytes_requested_total = num_bytes_requested_per_cpu * num_cpu;
+
+	/*
+	 * Try to get the `MemAvail` field of `/proc/meminfo`. This is the most
+	 * reliable estimate we can get but it is only exposed by the kernel
+	 * since 3.14. (See Linux kernel commit:
+	 * 34e431b0ae398fc54ea69ff85ec700722c9da773)
+	 */
+	ret = utils_get_memory_available(&best_mem_info);
+	if (ret >= 0) {
+		goto success;
+	}
+
+	/*
+	 * As a backup plan, use `MemTotal` field of `/proc/meminfo`. This
+	 * is a sanity check for obvious user error.
+	 */
+	ret = utils_get_memory_total(&best_mem_info);
+	if (ret >= 0) {
+		goto success;
+	}
+
+error:
+	return -1;
+success:
+	return best_mem_info >= num_bytes_requested_total;
+}
+
 /*
  * Try connect to session daemon with sock_path.
  *
@@ -379,17 +424,12 @@ error:
 /*
  * Connect to the LTTng session daemon.
  *
- * On success, return 0. On error, return -1.
+ * On success, return the socket's file descriptor. On error, return -1.
  */
-static int connect_sessiond(void)
+LTTNG_HIDDEN int connect_sessiond(void)
 {
 	int ret;
 
-	/* Don't try to connect if already connected. */
-	if (connected) {
-		return 0;
-	}
-
 	ret = set_session_daemon_path();
 	if (ret < 0) {
 		goto error;
@@ -401,15 +441,18 @@ static int connect_sessiond(void)
 		goto error;
 	}
 
-	sessiond_socket = ret;
-	connected = 1;
-
-	return 0;
+	return ret;
 
 error:
 	return -1;
 }
 
+static void reset_global_sessiond_connection_state(void)
+{
+	sessiond_socket = -1;
+	connected = 0;
+}
+
 /*
  *  Clean disconnect from the session daemon.
  *
@@ -421,8 +464,7 @@ static int disconnect_sessiond(void)
 
 	if (connected) {
 		ret = lttcomm_close_unix_sock(sessiond_socket);
-		sessiond_socket = 0;
-		connected = 0;
+		reset_global_sessiond_connection_state();
 	}
 
 	return ret;
@@ -497,6 +539,9 @@ int lttng_ctl_ask_sessiond_fds_varlen(struct lttcomm_session_msg *lsm,
 	if (ret < 0) {
 		ret = -LTTNG_ERR_NO_SESSIOND;
 		goto end;
+	} else {
+		sessiond_socket = ret;
+		connected = 1;
 	}
 
 	/* Send command to session daemon */
@@ -679,7 +724,7 @@ static int _lttng_stop_tracing(const char *session_name, int wait)
 		 * call returned value indicates availability.
 		 */
 		if (data_ret) {
-			usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME);
+			usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME_US);
 		}
 	} while (data_ret != 0);
 
@@ -1033,6 +1078,13 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 	bool send_fd = false;
 	unsigned int free_filter_expression = 0;
 	struct filter_parser_ctx *ctx = NULL;
+
+	/*
+	 * We have either a filter or some exclusions, so we need to set up
+	 * a variable-length memory block from where to send the data.
+	 */
+	lttng_dynamic_buffer_init(&send_buffer);
+
 	/*
 	 * Cast as non-const since we may replace the filter expression
 	 * by a dynamically allocated string. Otherwise, the original
@@ -1081,12 +1133,6 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 	lsm.u.enable.exclusion_count = exclusion_count;
 	lsm.u.enable.bytecode_len = 0;
 
-	/*
-	 * We have either a filter or some exclusions, so we need to set up
-	 * a variable-length memory block from where to send the data.
-	 */
-	lttng_dynamic_buffer_init(&send_buffer);
-
 	/* Parse filter expression. */
 	if (filter_expression != NULL || handle->domain.type == LTTNG_DOMAIN_JUL
 			|| handle->domain.type == LTTNG_DOMAIN_LOG4J
@@ -1180,7 +1226,7 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 			ret = lttng_userspace_probe_location_serialize(
 				ev_ext->probe_location, &send_buffer,
 				&fd_to_send);
-			if (ret) {
+			if (ret < 0) {
 				goto mem_error;
 			}
 
@@ -1472,6 +1518,7 @@ int lttng_enable_channel(struct lttng_handle *handle,
 		struct lttng_channel *in_chan)
 {
 	struct lttcomm_session_msg lsm;
+	size_t total_buffer_size_needed_per_cpu = 0;
 
 	/* NULL arguments are forbidden. No default values. */
 	if (handle == NULL || in_chan == NULL) {
@@ -1507,6 +1554,16 @@ int lttng_enable_channel(struct lttng_handle *handle,
 		memcpy(&lsm.u.channel.extended, extended, sizeof(*extended));
 	}
 
+	/*
+	 * Verify that the amount of memory required to create the requested
+	 * buffer is available on the system at the moment.
+	 */
+	total_buffer_size_needed_per_cpu = lsm.u.channel.chan.attr.num_subbuf *
+		lsm.u.channel.chan.attr.subbuf_size;
+	if (!check_enough_available_memory(total_buffer_size_needed_per_cpu)) {
+		return -LTTNG_ERR_NOMEM;
+	}
+
 	lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
 	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
@@ -1690,81 +1747,296 @@ const char *lttng_strerror(int code)
 	return error_get_str(code);
 }
 
+enum lttng_error_code lttng_create_session_ext(
+		struct lttng_session_descriptor *session_descriptor)
+{
+	enum lttng_error_code ret_code;
+	struct lttcomm_session_msg lsm = {
+		.cmd_type = LTTNG_CREATE_SESSION_EXT,
+	};
+	void *reply = NULL;
+	struct lttng_buffer_view reply_view;
+	int reply_ret;
+	bool sessiond_must_generate_ouput;
+	struct lttng_dynamic_buffer payload;
+	int ret;
+	size_t descriptor_size;
+	struct lttng_session_descriptor *descriptor_reply = NULL;
+
+	lttng_dynamic_buffer_init(&payload);
+	if (!session_descriptor) {
+		ret_code = LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	sessiond_must_generate_ouput =
+			!lttng_session_descriptor_is_output_destination_initialized(
+				session_descriptor);
+	if (sessiond_must_generate_ouput) {
+		const char *home_dir = utils_get_home_dir();
+		size_t home_dir_len = home_dir ? strlen(home_dir) + 1 : 0;
+
+		if (!home_dir || home_dir_len > LTTNG_PATH_MAX) {
+			ret_code = LTTNG_ERR_FATAL;
+			goto end;
+		}
+
+		lsm.u.create_session.home_dir_size = (uint16_t) home_dir_len;
+		ret = lttng_dynamic_buffer_append(&payload, home_dir,
+				home_dir_len);
+		if (ret) {
+			ret_code = LTTNG_ERR_NOMEM;
+			goto end;
+		}
+	}
+
+	descriptor_size = payload.size;
+	ret = lttng_session_descriptor_serialize(session_descriptor,
+			&payload);
+	if (ret) {
+		ret_code = LTTNG_ERR_INVALID;
+		goto end;
+	}
+	descriptor_size = payload.size - descriptor_size;
+	lsm.u.create_session.session_descriptor_size = descriptor_size;
+
+	/* Command returns a session descriptor on success. */
+	reply_ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, payload.data,
+			payload.size, &reply);
+	if (reply_ret < 0) {
+		ret_code = -reply_ret;
+		goto end;
+	} else if (reply_ret == 0) {
+		/* Socket unexpectedly closed by the session daemon. */
+		ret_code = LTTNG_ERR_FATAL;
+		goto end;
+	}
+
+	reply_view = lttng_buffer_view_init(reply, 0, reply_ret);
+	ret = lttng_session_descriptor_create_from_buffer(&reply_view,
+			&descriptor_reply);
+	if (ret < 0) {
+		ret_code = LTTNG_ERR_FATAL;
+		goto end;
+	}
+	ret_code = LTTNG_OK;
+	lttng_session_descriptor_assign(session_descriptor, descriptor_reply);
+end:
+	free(reply);
+	lttng_dynamic_buffer_reset(&payload);
+	lttng_session_descriptor_destroy(descriptor_reply);
+	return ret_code;
+}
+
 /*
- * Create a brand new session using name and url for destination.
+ * Create a new session using name and url for destination.
  *
- * Returns LTTNG_OK on success or a negative error code.
+ * Return 0 on success else a negative LTTng error code.
  */
 int lttng_create_session(const char *name, const char *url)
 {
 	int ret;
 	ssize_t size;
-	struct lttcomm_session_msg lsm;
 	struct lttng_uri *uris = NULL;
+	struct lttng_session_descriptor *descriptor = NULL;
+	enum lttng_error_code ret_code;
 
-	if (name == NULL) {
-		return -LTTNG_ERR_INVALID;
+	if (!name) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	/* There should never be a data URL */
 	size = uri_parse_str_urls(url, NULL, &uris);
 	if (size < 0) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	switch (size) {
+	case 0:
+		descriptor = lttng_session_descriptor_create(name);
+		break;
+	case 1:
+		if (uris[0].dtype != LTTNG_DST_PATH) {
+			ret = -LTTNG_ERR_INVALID;
+			goto end;
+		}
+		descriptor = lttng_session_descriptor_local_create(name,
+				uris[0].dst.path);
+		break;
+	case 2:
+		descriptor = lttng_session_descriptor_network_create(name, url,
+				NULL);
+		break;
+	default:
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	if (!descriptor) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
+	ret_code = lttng_create_session_ext(descriptor);
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
+end:
+	lttng_session_descriptor_destroy(descriptor);
+	free(uris);
+	return ret;
+}
 
-	lsm.u.uri.size = size;
+/*
+ * Create a session exclusively used for snapshot.
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+int lttng_create_session_snapshot(const char *name, const char *snapshot_url)
+{
+	int ret;
+	enum lttng_error_code ret_code;
+	ssize_t size;
+	struct lttng_uri *uris = NULL;
+	struct lttng_session_descriptor *descriptor = NULL;
 
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
+	if (!name) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
+	size = uri_parse_str_urls(snapshot_url, NULL, &uris);
+	if (size < 0) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	/*
+	 * If the user does not specify a custom subdir, use the session name.
+	 */
+	if (size > 0 && uris[0].dtype != LTTNG_DST_PATH &&
+			strlen(uris[0].subdir) == 0) {
+		ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s",
+				name);
+		if (ret < 0) {
+			PERROR("Failed to set session name as network destination sub-directory");
+			ret = -LTTNG_ERR_FATAL;
+			goto end;
+		} else if (ret >= sizeof(uris[0].subdir)) {
+			/* Truncated output. */
+			ret = -LTTNG_ERR_INVALID;
+			goto end;
+		}
+	}
+
+	switch (size) {
+	case 0:
+		descriptor = lttng_session_descriptor_snapshot_create(name);
+		break;
+	case 1:
+		if (uris[0].dtype != LTTNG_DST_PATH) {
+			ret = -LTTNG_ERR_INVALID;
+			goto end;
+		}
+		descriptor = lttng_session_descriptor_snapshot_local_create(
+				name,
+				uris[0].dst.path);
+		break;
+	case 2:
+		descriptor = lttng_session_descriptor_snapshot_network_create(
+				name,
+				snapshot_url,
+				NULL);
+		break;
+	default:
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	if (!descriptor) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	ret_code = lttng_create_session_ext(descriptor);
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
+end:
+	lttng_session_descriptor_destroy(descriptor);
 	free(uris);
 	return ret;
 }
 
 /*
- * Destroy session using name.
- * Returns size of returned session payload data or a negative error code.
+ * Create a session exclusively used for live.
+ *
+ * Return 0 on success else a negative LTTng error code.
  */
-static
-int _lttng_destroy_session(const char *session_name)
+int lttng_create_session_live(const char *name, const char *url,
+		unsigned int timer_interval)
 {
-	struct lttcomm_session_msg lsm;
+	int ret;
+	enum lttng_error_code ret_code;
+	struct lttng_session_descriptor *descriptor = NULL;
 
-	if (session_name == NULL) {
-		return -LTTNG_ERR_INVALID;
+	if (!name) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-	lsm.cmd_type = LTTNG_DESTROY_SESSION;
-
-	lttng_ctl_copy_string(lsm.session.name, session_name,
-			sizeof(lsm.session.name));
-
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
+	if (url) {
+		descriptor = lttng_session_descriptor_live_network_create(
+				name, url, NULL, timer_interval);
+	} else {
+		descriptor = lttng_session_descriptor_live_create(
+				name, timer_interval);
+	}
+	if (!descriptor) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	ret_code = lttng_create_session_ext(descriptor);
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
+end:
+	lttng_session_descriptor_destroy(descriptor);
+	return ret;
 }
 
 /*
  * Stop the session and wait for the data before destroying it
+ *
+ * Return 0 on success else a negative LTTng error code.
  */
 int lttng_destroy_session(const char *session_name)
 {
 	int ret;
+	enum lttng_error_code ret_code;
+	enum lttng_destruction_handle_status status;
+	struct lttng_destruction_handle *handle = NULL;
 
 	/*
-	 * Stop the tracing and wait for the data.
+	 * Stop the tracing and wait for the data to be
+	 * consumed.
 	 */
 	ret = _lttng_stop_tracing(session_name, 1);
 	if (ret && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
 		goto end;
 	}
 
-	ret = _lttng_destroy_session(session_name);
+	ret_code = lttng_destroy_session_ext(session_name, &handle);
+	if (ret_code != LTTNG_OK) {
+		ret = (int) -ret_code;
+		goto end;
+	}
+	assert(handle);
+
+	/* Block until the completion of the destruction of the session. */
+	status = lttng_destruction_handle_wait_for_completion(handle, -1);
+	if (status != LTTNG_DESTRUCTION_HANDLE_STATUS_COMPLETED) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+
+	status = lttng_destruction_handle_get_result(handle, &ret_code);
+	if (status != LTTNG_DESTRUCTION_HANDLE_STATUS_OK) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
 end:
+	lttng_destruction_handle_destroy(handle);
 	return ret;
 }
 
@@ -1773,21 +2045,10 @@ end:
  */
 int lttng_destroy_session_no_wait(const char *session_name)
 {
-	int ret;
-
-	/*
-	 * Stop the tracing without waiting for the data.
-	 * The session might already have been stopped, so just
-	 * skip this error.
-	 */
-	ret = _lttng_stop_tracing(session_name, 0);
-	if (ret && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
-		goto end;
-	}
+	enum lttng_error_code ret_code;
 
-	ret = _lttng_destroy_session(session_name);
-end:
-	return ret;
+	ret_code = lttng_destroy_session_ext(session_name, NULL);
+	return ret_code == LTTNG_OK ? ret_code : -ret_code;
 }
 
 /*
@@ -1796,19 +2057,72 @@ end:
  * Returns the number of lttng_session entries in sessions;
  * on error, returns a negative value.
  */
-int lttng_list_sessions(struct lttng_session **sessions)
+int lttng_list_sessions(struct lttng_session **out_sessions)
 {
 	int ret;
 	struct lttcomm_session_msg lsm;
+	const size_t session_size = sizeof(struct lttng_session) +
+			sizeof(struct lttng_session_extended);
+	size_t session_count, i;
+	struct lttng_session_extended *sessions_extended_begin;
+	struct lttng_session *sessions = NULL;
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_SESSIONS;
-	ret = lttng_ctl_ask_sessiond(&lsm, (void**) sessions);
-	if (ret < 0) {
-		return ret;
+	ret = lttng_ctl_ask_sessiond(&lsm, (void**) &sessions);
+	if (ret <= 0) {
+		goto end;
+	}
+	if (!sessions) {
+		ret = -LTTNG_ERR_FATAL;
+		goto end;
+	}
+
+	if (ret % session_size) {
+		ret = -LTTNG_ERR_UNK;
+		free(sessions);
+		*out_sessions = NULL;
+		goto end;
 	}
+	session_count = (size_t) ret / session_size;
+	sessions_extended_begin = (struct lttng_session_extended *)
+			(&sessions[session_count]);
 
-	return ret / sizeof(struct lttng_session);
+	/* Set extended session info pointers. */
+	for (i = 0; i < session_count; i++) {
+		struct lttng_session *session = &sessions[i];
+		struct lttng_session_extended *extended =
+				&(sessions_extended_begin[i]);
+
+		session->extended.ptr = extended;
+	}
+
+	ret = (int) session_count;
+	*out_sessions = sessions;
+end:
+	return ret;
+}
+
+enum lttng_error_code lttng_session_get_creation_time(
+		const struct lttng_session *session, uint64_t *creation_time)
+{
+	enum lttng_error_code ret = LTTNG_OK;
+	struct lttng_session_extended *extended;
+
+	if (!session || !creation_time || !session->extended.ptr) {
+		ret = LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	extended = session->extended.ptr;
+	if (!extended->creation_time.is_set) {
+		/* Not created on the session daemon yet. */
+		ret = LTTNG_ERR_SESSION_NOT_EXIST;
+		goto end;
+	}
+	*creation_time = extended->creation_time.value;
+end:
+	return ret;
 }
 
 int lttng_set_session_shm_path(const char *session_name,
@@ -1932,9 +2246,8 @@ int lttng_list_events(struct lttng_handle *handle,
 	size_t cmd_header_len;
 	uint32_t nb_events, i;
 	void *comm_ext_at;
-	void *listing_at;
 	char *reception_buffer = NULL;
-	char *listing = NULL;
+	struct lttng_dynamic_buffer listing;
 	size_t storage_req;
 
 	/* Safety check. An handle and channel name are mandatory */
@@ -1957,6 +2270,11 @@ int lttng_list_events(struct lttng_handle *handle,
 		goto end;
 	}
 
+	if (!cmd_header) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+
 	/* Set number of events and free command header */
 	nb_events = cmd_header->nb_events;
 	if (nb_events > INT_MAX) {
@@ -1970,12 +2288,12 @@ int lttng_list_events(struct lttng_handle *handle,
 	 * The buffer that is returned must contain a "flat" version of
 	 * the events that are returned. In other words, all pointers
 	 * within an lttng_event must point to a location within the returned
-	 * buffer so that the user may free by simply calling free() on the
-	 * returned buffer. This is needed in order to maintain API
+	 * buffer so that the user may free everything by simply calling free()
+	 * on the returned buffer. This is needed in order to maintain API
 	 * compatibility.
 	 *
-	 * A first pass is performed to figure the size of the buffer that
-	 * must be returned. A second pass is then performed to setup
+	 * A first pass is performed to compute the size of the buffer that
+	 * must be allocated. A second pass is then performed to setup
 	 * the returned events so that their members always point within the
 	 * buffer.
 	 *
@@ -1995,66 +2313,170 @@ int lttng_list_events(struct lttng_handle *handle,
 	for (i = 0; i < nb_events; i++) {
 		struct lttcomm_event_extended_header *ext_comm =
 			(struct lttcomm_event_extended_header *) comm_ext_at;
+		int probe_storage_req = 0;
 
 		comm_ext_at += sizeof(*ext_comm);
 		comm_ext_at += ext_comm->filter_len;
 		comm_ext_at +=
 			ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
 
+		if (ext_comm->userspace_probe_location_len) {
+			struct lttng_userspace_probe_location *probe_location = NULL;
+			struct lttng_buffer_view probe_location_view;
+
+			probe_location_view = lttng_buffer_view_init(
+					comm_ext_at, 0,
+					ext_comm->userspace_probe_location_len);
+
+			/*
+			 * Create a temporary userspace probe location to
+			 * determine the size needed by a "flattened" version
+			 * of that same probe location.
+			 */
+			ret = lttng_userspace_probe_location_create_from_buffer(
+					&probe_location_view, &probe_location);
+			if (ret < 0) {
+				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+				goto end;
+			}
+
+			ret = lttng_userspace_probe_location_flatten(
+					probe_location, NULL);
+			lttng_userspace_probe_location_destroy(probe_location);
+			if (ret < 0) {
+				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+				goto end;
+			}
+
+			probe_storage_req = ret;
+			comm_ext_at += ext_comm->userspace_probe_location_len;
+		}
+
 		storage_req += sizeof(struct lttng_event_extended);
-		/* TODO: missing size of flat userspace probe. */
 		storage_req += ext_comm->filter_len;
 		storage_req += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
-		storage_req += storage_req % 8;
+		/* Padding to ensure the flat probe is aligned. */
+		storage_req = ALIGN_TO(storage_req, sizeof(uint64_t));
+		storage_req += probe_storage_req;
 	}
 
-	listing = zmalloc(storage_req);
-	if (!listing) {
+	lttng_dynamic_buffer_init(&listing);
+	/*
+	 * We must ensure that "listing" is never resized so as to preserve
+	 * the validity of the flattened objects.
+	 */
+	ret = lttng_dynamic_buffer_set_capacity(&listing, storage_req);
+	if (ret) {
+		ret = -LTTNG_ERR_NOMEM;
 		goto end;
 	}
-	memcpy(listing, reception_buffer,
-		nb_events * sizeof(struct lttng_event));
+
+	ret = lttng_dynamic_buffer_append(&listing, reception_buffer,
+			nb_events * sizeof(struct lttng_event));
+	if (ret) {
+		ret = -LTTNG_ERR_NOMEM;
+		goto free_dynamic_buffer;
+	}
 
 	comm_ext_at = reception_buffer +
-		(nb_events * sizeof(struct lttng_event));
-	listing_at = listing +
-		(nb_events * sizeof(struct lttng_event));
+			(nb_events * sizeof(struct lttng_event));
 	for (i = 0; i < nb_events; i++) {
 		struct lttng_event *event = (struct lttng_event *)
-			(listing + (sizeof(struct lttng_event) * i));
+			(listing.data + (sizeof(struct lttng_event) * i));
 		struct lttcomm_event_extended_header *ext_comm =
 			(struct lttcomm_event_extended_header *) comm_ext_at;
 		struct lttng_event_extended *event_extended =
-			(struct lttng_event_extended *) listing_at;
+			(struct lttng_event_extended *)
+				(listing.data + listing.size);
 
+		/* Insert struct lttng_event_extended. */
+		ret = lttng_dynamic_buffer_set_size(&listing,
+				listing.size + sizeof(*event_extended));
+		if (ret) {
+			ret = -LTTNG_ERR_NOMEM;
+			goto free_dynamic_buffer;
+		}
 		event->extended.ptr = event_extended;
-		listing_at += sizeof(*event_extended);
+
 		comm_ext_at += sizeof(*ext_comm);
 
-		/* Copy filter expression. */
-		memcpy(listing_at, comm_ext_at, ext_comm->filter_len);
-		event_extended->filter_expression = listing_at;
-		comm_ext_at += ext_comm->filter_len;
-		listing_at += ext_comm->filter_len;
+		/* Insert filter expression. */
+		if (ext_comm->filter_len) {
+			event_extended->filter_expression = listing.data +
+					listing.size;
+			ret = lttng_dynamic_buffer_append(&listing, comm_ext_at,
+					ext_comm->filter_len);
+			if (ret) {
+				ret = -LTTNG_ERR_NOMEM;
+				goto free_dynamic_buffer;
+			}
+			comm_ext_at += ext_comm->filter_len;
+		}
+
+		/* Insert exclusions. */
+		if (ext_comm->nb_exclusions) {
+			event_extended->exclusions.count =
+					ext_comm->nb_exclusions;
+			event_extended->exclusions.strings =
+					listing.data + listing.size;
+
+			ret = lttng_dynamic_buffer_append(&listing,
+					comm_ext_at,
+					ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN);
+			if (ret) {
+				ret = -LTTNG_ERR_NOMEM;
+				goto free_dynamic_buffer;
+			}
+			comm_ext_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+		}
 
-		/* Copy exclusions. */
-		event_extended->exclusions.count = ext_comm->nb_exclusions;
-		event_extended->exclusions.strings = listing_at;
-		memcpy(listing_at, comm_ext_at,
-			ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN);
-		listing_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
-		comm_ext_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+		/* Insert padding to align to 64-bits. */
+		ret = lttng_dynamic_buffer_set_size(&listing,
+				ALIGN_TO(listing.size, sizeof(uint64_t)));
+		if (ret) {
+			ret = -LTTNG_ERR_NOMEM;
+			goto free_dynamic_buffer;
+		}
+
+		/* Insert flattened userspace probe location. */
+		if (ext_comm->userspace_probe_location_len) {
+			struct lttng_userspace_probe_location *probe_location = NULL;
+			struct lttng_buffer_view probe_location_view;
+
+			probe_location_view = lttng_buffer_view_init(
+					comm_ext_at, 0,
+					ext_comm->userspace_probe_location_len);
+
+			ret = lttng_userspace_probe_location_create_from_buffer(
+					&probe_location_view, &probe_location);
+			if (ret < 0) {
+				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+				goto free_dynamic_buffer;
+			}
 
-		listing_at += ((uintptr_t) listing_at) % 8;
+			event_extended->probe_location = (struct lttng_userspace_probe_location *)
+					(listing.data + listing.size);
+			ret = lttng_userspace_probe_location_flatten(
+					probe_location, &listing);
+			lttng_userspace_probe_location_destroy(probe_location);
+			if (ret < 0) {
+				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+				goto free_dynamic_buffer;
+			}
+
+			comm_ext_at += ext_comm->userspace_probe_location_len;
+		}
 	}
 
-	*events = (struct lttng_event *) listing;
-	listing = NULL;
+	/* Don't reset listing buffer as we return its content. */
+	*events = (struct lttng_event *) listing.data;
+	lttng_dynamic_buffer_init(&listing);
 	ret = (int) nb_events;
+free_dynamic_buffer:
+	lttng_dynamic_buffer_reset(&listing);
 end:
 	free(cmd_header);
 	free(reception_buffer);
-	free(listing);
 	return ret;
 }
 
@@ -2399,71 +2821,12 @@ int lttng_disable_consumer(struct lttng_handle *handle)
 }
 
 /*
- * This is an extension of create session that is ONLY and SHOULD only be used
- * by the lttng command line program. It exists to avoid using URI parsing in
- * the lttng client.
- *
- * We need the date and time for the trace path subdirectory for the case where
- * the user does NOT define one using either -o or -U. Using the normal
- * lttng_create_session API call, we have no clue on the session daemon side if
- * the URL was generated automatically by the client or define by the user.
- *
- * So this function "wrapper" is hidden from the public API, takes the datetime
- * string and appends it if necessary to the URI subdirectory before sending it
- * to the session daemon.
- *
- * With this extra function, the lttng_create_session call behavior is not
- * changed and the timestamp is appended to the URI on the session daemon side
- * if necessary.
+ * [OBSOLETE]
  */
 int _lttng_create_session_ext(const char *name, const char *url,
 		const char *datetime)
 {
-	int ret;
-	ssize_t size;
-	struct lttcomm_session_msg lsm;
-	struct lttng_uri *uris = NULL;
-
-	if (name == NULL || datetime == NULL) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	/* There should never be a data URL. */
-	size = uri_parse_str_urls(url, NULL, &uris);
-	if (size < 0) {
-		ret = -LTTNG_ERR_INVALID;
-		goto error;
-	}
-
-	lsm.u.uri.size = size;
-
-	if (size > 0 && uris[0].dtype != LTTNG_DST_PATH && strlen(uris[0].subdir) == 0) {
-		/* Don't append datetime if the name was automatically created. */
-		if (strncmp(name, DEFAULT_SESSION_NAME "-",
-					strlen(DEFAULT_SESSION_NAME) + 1)) {
-			ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s-%s",
-					name, datetime);
-		} else {
-			ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s", name);
-		}
-		if (ret < 0) {
-			PERROR("snprintf uri subdir");
-			ret = -LTTNG_ERR_FATAL;
-			goto error;
-		}
-	}
-
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
-
-error:
-	free(uris);
-	return ret;
+	return -ENOSYS;
 }
 
 /*
@@ -2494,6 +2857,10 @@ int lttng_data_pending(const char *session_name)
 		/* Unexpected payload size */
 		ret = -LTTNG_ERR_INVALID;
 		goto end;
+	} else if (!pending) {
+		/* Internal error. */
+		ret = -LTTNG_ERR_UNK;
+		goto end;
 	}
 
 	ret = (int) *pending;
@@ -2502,103 +2869,6 @@ end:
 	return ret;
 }
 
-/*
- * Create a session exclusively used for snapshot.
- *
- * Returns LTTNG_OK on success or a negative error code.
- */
-int lttng_create_session_snapshot(const char *name, const char *snapshot_url)
-{
-	int ret;
-	ssize_t size;
-	struct lttcomm_session_msg lsm;
-	struct lttng_uri *uris = NULL;
-
-	if (name == NULL) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION_SNAPSHOT;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	size = uri_parse_str_urls(snapshot_url, NULL, &uris);
-	if (size < 0) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	lsm.u.uri.size = size;
-
-	/*
-	 * If the user does not specify a custom subdir, use the session name.
-	 */
-	if (size > 0 && uris[0].dtype != LTTNG_DST_PATH && strlen(uris[0].subdir) == 0) {
-		ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s", name);
-		if (ret < 0) {
-			PERROR("snprintf uri subdir");
-			ret = -LTTNG_ERR_FATAL;
-			goto error;
-		}
-	}
-
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
-
-error:
-	free(uris);
-	return ret;
-}
-
-/*
- * Create a session exclusively used for live.
- *
- * Returns LTTNG_OK on success or a negative error code.
- */
-int lttng_create_session_live(const char *name, const char *url,
-		unsigned int timer_interval)
-{
-	int ret;
-	ssize_t size;
-	struct lttcomm_session_msg lsm;
-	struct lttng_uri *uris = NULL;
-
-	if (name == NULL || timer_interval == 0) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION_LIVE;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	if (url) {
-		size = uri_parse_str_urls(url, NULL, &uris);
-		if (size <= 0) {
-			ret = -LTTNG_ERR_INVALID;
-			goto end;
-		}
-
-		/* file:// is not accepted for live session. */
-		if (uris[0].dtype == LTTNG_DST_PATH) {
-			ret = -LTTNG_ERR_INVALID;
-			goto end;
-		}
-	} else {
-		size = 0;
-	}
-
-	lsm.u.session_live.nb_uri = size;
-	lsm.u.session_live.timer_interval = timer_interval;
-
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
-
-end:
-	free(uris);
-	return ret;
-}
-
 /*
  * List PIDs in the tracker.
  *
@@ -2616,7 +2886,7 @@ int lttng_list_tracker_pids(struct lttng_handle *handle,
 	int enabled = 1;
 	struct lttcomm_session_msg lsm;
 	size_t nr_pids;
-	int32_t *pids;
+	int32_t *pids = NULL;
 
 	if (handle == NULL) {
 		return -LTTNG_ERR_INVALID;
@@ -2633,6 +2903,9 @@ int lttng_list_tracker_pids(struct lttng_handle *handle,
 		return ret;
 	}
 	nr_pids = ret / sizeof(int32_t);
+	if (nr_pids > 0 && !pids) {
+		return -LTTNG_ERR_UNK;
+	}
 	if (nr_pids == 1 && pids[0] == -1) {
 		free(pids);
 		pids = NULL;
@@ -2779,50 +3052,6 @@ end:
 	return ret;
 }
 
-int lttng_session_get_current_archive_location(const char *session_name,
-		char **chunk_path)
-{
-	struct lttcomm_session_msg lsm;
-	struct lttng_session_get_current_output_return *output_return = NULL;
-	int ret;
-	size_t path_len;
-
-	memset(&lsm, 0, sizeof(lsm));
-	lsm.cmd_type = LTTNG_SESSION_GET_CURRENT_OUTPUT;
-	ret = lttng_strncpy(lsm.session.name, session_name,
-			sizeof(lsm.session.name));
-	if (ret) {
-		ret = -LTTNG_ERR_INVALID;
-		goto end;
-	}
-
-	ret = lttng_ctl_ask_sessiond(&lsm, (void **) &output_return);
-	if (ret < 0) {
-		ret = -1;
-		goto end;
-	}
-
-	path_len = lttng_strnlen(output_return->path,
-			sizeof(output_return->path));
-	if (path_len == 0 || path_len == sizeof(output_return->path)) {
-		ret = -LTTNG_ERR_NO_SESSION_OUTPUT;
-		goto end;
-	}
-
-	*chunk_path = zmalloc(path_len + 1);
-	if (!*chunk_path) {
-		ret = -1;
-		goto end;
-	}
-	memcpy(*chunk_path, output_return->path, path_len);
-
-	ret = 0;
-
-end:
-	free(output_return);
-	return ret;
-}
-
 /*
  * lib constructor.
  */