[lttng-tools.git] / liblttngctl / liblttngctl.c

/*
 * 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 <errno.h>
#include <grp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <lttng/lttng.h>

#include "liblttsessiondcomm.h"
#include "lttngerr.h"
#include "lttng-share.h"

/* Socket to session daemon for communication */
static int sessiond_socket;
static char sessiond_sock_path[PATH_MAX];

/* Communication structure to ltt-sessiond */
static struct lttcomm_session_msg lsm;
static struct lttcomm_lttng_msg llm;

/* Variables */
static char *tracing_group;
static int connected;

/*
 *  send_data_sessiond
 *
 *  Send lttcomm_session_msg to the session daemon.
 *
 *  On success, return 0
 *  On error, return error code
 */
static int send_data_sessiond(void)
{
	int ret;

	if (!connected) {
		ret = -ENOTCONN;
		goto end;
	}

	ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));

end:
	return ret;
}

/*
 *  recv_data_sessiond
 *
 *  Receive data from the sessiond socket.
 *
 *  On success, return 0
 *  On error, return recv() error code
 */
static int recv_data_sessiond(void *buf, size_t len)
{
	int ret;

	if (!connected) {
		ret = -ENOTCONN;
		goto end;
	}

	ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);

end:
	return ret;
}

/*
 *  ask_sessiond
 *
 *  Ask the session daemon a specific command and put the data into buf.
 *
 *  Return size of data (only payload, not header).
 */
static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf)
{
	int ret;
	size_t size;
	void *data = NULL;

	ret = lttng_connect_sessiond();
	if (ret < 0) {
		goto end;
	}

	lsm.cmd_type = lct;

	/* Send command to session daemon */
	ret = send_data_sessiond();
	if (ret < 0) {
		goto end;
	}

	/* Get header from data transmission */
	ret = recv_data_sessiond(&llm, sizeof(llm));
	if (ret < 0) {
		goto end;
	}

	/* Check error code if OK */
	if (llm.ret_code != LTTCOMM_OK) {
		ret = -llm.ret_code;
		goto end;
	}

	size = llm.data_size;
	if (size == 0) {
		goto end;
	}

	data = (void*) malloc(size);

	/* Get payload data */
	ret = recv_data_sessiond(data, size);
	if (ret < 0) {
		free(data);
		goto end;
	}

	*buf = data;
	ret = size;

end:
	lttng_disconnect_sessiond();
	return ret;
}

/*
 *  check_tracing_group
 *
 *  Check if the specified group name exist.
 *  If yes, 0, else -1
 */
static int check_tracing_group(const char *grp_name)
{
	struct group *grp_tracing;	/* no free(). See getgrnam(3) */
	gid_t *grp_list;
	int grp_list_size, grp_id, i;
	int ret = -1;

	/* Get GID of group 'tracing' */
	grp_tracing = getgrnam(grp_name);
	if (grp_tracing == NULL) {
		/* NULL means not found also. getgrnam(3) */
		if (errno != 0) {
			perror("getgrnam");
		}
		goto end;
	}

	/* Get number of supplementary group IDs */
	grp_list_size = getgroups(0, NULL);
	if (grp_list_size < 0) {
		perror("getgroups");
		goto end;
	}

	/* Alloc group list of the right size */
	grp_list = malloc(grp_list_size * sizeof(gid_t));
	grp_id = getgroups(grp_list_size, grp_list);
	if (grp_id < -1) {
		perror("getgroups");
		goto free_list;
	}

	for (i = 0; i < grp_list_size; i++) {
		if (grp_list[i] == grp_tracing->gr_gid) {
			ret = 0;
			break;
		}
	}

free_list:
	free(grp_list);

end:
	return ret;
}

/*
 *  set_session_daemon_path
 *
 *  Set sessiond socket path by putting it in 
 *  the global sessiond_sock_path variable.
 */
static int set_session_daemon_path(void)
{
	int ret;

	/* Are we in the tracing group ? */
	ret = check_tracing_group(tracing_group);
	if (ret < 0 && getuid() != 0) {
		if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
					getenv("HOME")) < 0) {
			return -ENOMEM;
		}
	} else {
		strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
				sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
	}

	return 0;
}

/*
 *  lttng_start_tracing
 *
 *  Start tracing for all trace of the session.
 */
int lttng_start_tracing(char *session_name)
{
	strncpy(lsm.session_name, session_name, NAME_MAX);
	return ask_sessiond(LTTNG_START_TRACE, NULL);
}

/*
 *  lttng_stop_tracing
 *
 *  Stop tracing for all trace of the session.
 */
int lttng_stop_tracing(char *session_name)
{
	strncpy(lsm.session_name, session_name, NAME_MAX);
	return ask_sessiond(LTTNG_STOP_TRACE, NULL);
}

/*
 * BEGIN Kernel control API
 */

/*
 *  lttng_kernel_add_context
 */
int lttng_kernel_add_context(struct lttng_kernel_context *ctx,
		char *event_name, char *channel_name)
{
	if (channel_name != NULL) {
		strncpy(lsm.u.context.channel_name, channel_name, NAME_MAX);
	}

	if (event_name != NULL) {
		strncpy(lsm.u.context.event_name, event_name, NAME_MAX);
	}

	memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_kernel_context));
	return ask_sessiond(LTTNG_KERNEL_ADD_CONTEXT, NULL);
}

/*
 *  lttng_kernel_enable_event
 */
int lttng_kernel_enable_event(struct lttng_event *ev, char *channel_name)
{
	int ret;

	if (channel_name == NULL) {
		strncpy(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
	} else {
		strncpy(lsm.u.enable.channel_name, channel_name, NAME_MAX);
	}

	if (ev == NULL) {
		ret = ask_sessiond(LTTNG_KERNEL_ENABLE_ALL_EVENT, NULL);
	} else {
		memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event));
		ret = ask_sessiond(LTTNG_KERNEL_ENABLE_EVENT, NULL);
	}

	return ret;
}

/*
 *  lttng_kernel_disable_event
 *
 *  Disable an event in the kernel tracer.
 */
int lttng_kernel_disable_event(char *name, char *channel_name)
{
	int ret;

	if (channel_name == NULL) {
		strncpy(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
	} else {
		strncpy(lsm.u.disable.channel_name, channel_name, NAME_MAX);
	}

	if (name == NULL) {
		ret = ask_sessiond(LTTNG_KERNEL_DISABLE_ALL_EVENT, NULL);
	} else {
		strncpy(lsm.u.disable.name, name, NAME_MAX);
		ret = ask_sessiond(LTTNG_KERNEL_DISABLE_EVENT, NULL);
	}

	return ret;
}

/*
 *  lttng_kernel_enable_channel
 *
 *  Enable recording for a channel for the kernel tracer.
 */
int lttng_kernel_enable_channel(char *name)
{
	strncpy(lsm.u.enable.channel_name, name, NAME_MAX);
	return ask_sessiond(LTTNG_KERNEL_ENABLE_CHANNEL, NULL);
}

/*
 *  lttng_kernel_disable_channel
 *
 *  Disable recording for the channel for the kernel tracer.
 */
int lttng_kernel_disable_channel(char *name)
{
	strncpy(lsm.u.disable.channel_name, name, NAME_MAX);
	return ask_sessiond(LTTNG_KERNEL_DISABLE_CHANNEL, NULL);
}

/*
 *  lttng_kernel_create_channel
 *
 *  Create a channel in the kernel tracer.
 */
int lttng_kernel_create_channel(struct lttng_channel *chan)
{
	memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));
	return ask_sessiond(LTTNG_KERNEL_CREATE_CHANNEL, NULL);
}

/*
 *  lttng_list_events
 *
 *  List all available events in the kernel.
 *
 *  Return the size (bytes) of the list and set the event_list array.
 *  On error, return negative value.
 */
int lttng_kernel_list_events(char **event_list)
{
	return ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) event_list);
}

/*
 * END Kernel control API
 */

/*
 *  lttng_get_readable_code
 *
 *  Return a human readable string of code
 */
const char *lttng_get_readable_code(int code)
{
	if (code > -LTTCOMM_OK) {
		return "Ended with errors";
	}

	return lttcomm_get_readable_code(code);
}

/*
 *  lttng_ust_list_apps
 *
 *  Ask the session daemon for all UST traceable applications.
 *
 *  Return the number of pids.
 *  On error, return negative value.
 */
int lttng_ust_list_traceable_apps(pid_t **pids)
{
	int ret;

	ret = ask_sessiond(LTTNG_LIST_TRACEABLE_APPS, (void**) pids);
	if (ret < 0) {
		return ret;
	}

	return ret / sizeof(pid_t);
}

/*
 *  lttng_list_traces
 *
 *  Ask the session daemon for all traces (kernel and ust) for the session
 *  identified by name.
 *
 *  Return the number of traces.
 *  On error, return negative value.
 */
/*
int lttng_list_traces(char *session_name, struct lttng_trace **traces)
{
	int ret;

	strncpy(lsm.session_name, session_name, NAME_MAX);

	ret = ask_sessiond(LTTNG_LIST_TRACES, (void **) traces);
	if (ret < 0) {
		return ret;
	}

	return ret / sizeof(struct lttng_trace);
}
*/

/*
 *  lttng_create_session
 *
 *  Create a brand new session using name.
 */
int lttng_create_session(char *name, char *path)
{
	strncpy(lsm.session_name, name, NAME_MAX);
	strncpy(lsm.path, path, PATH_MAX);
	return ask_sessiond(LTTNG_CREATE_SESSION, NULL);
}

/*
 *  lttng_destroy_session
 *
 *  Destroy session using name.
 */
int lttng_destroy_session(char *name)
{
	strncpy(lsm.session_name, name, NAME_MAX);
	return ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
}

/*
 *  lttng_list_sessions
 *
 *  Ask the session daemon for all available sessions.
 *
 *  Return number of session.
 *  On error, return negative value.
 */
int lttng_list_sessions(struct lttng_session **sessions)
{
	int ret;

	ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
	if (ret < 0) {
		return ret;
	}

	return ret / sizeof(struct lttng_session);
}

/*
 *  lttng_connect_sessiond
 *
 *  Connect to the LTTng session daemon.
 *  On success, return 0
 *  On error, return a negative value
 */
int lttng_connect_sessiond(void)
{
	int ret;

	ret = set_session_daemon_path();
	if (ret < 0) {
		return ret;
	}

	/* Connect to the sesssion daemon */
	ret = lttcomm_connect_unix_sock(sessiond_sock_path);
	if (ret < 0) {
		return ret;
	}

	sessiond_socket = ret;
	connected = 1;

	return 0;
}

/*
 *  lttng_disconnect_sessiond
 *
 *  Clean disconnect the session daemon.
 */
int lttng_disconnect_sessiond(void)
{
	int ret = 0;

	if (connected) {
		ret = lttcomm_close_unix_sock(sessiond_socket);
		sessiond_socket = 0;
		connected = 0;
	}

	return ret;
}

void lttng_set_session_name(char *name)
{
	strncpy(lsm.session_name, name, NAME_MAX);
}

/*
 *  lttng_set_tracing_group
 *
 *  Set tracing group variable with name. This function
 *  allocate memory pointed by tracing_group.
 */
int lttng_set_tracing_group(const char *name)
{
	if (asprintf(&tracing_group, "%s", name) < 0) {
		return -ENOMEM;
	}

	return 0;
}

/*
 *  lttng_check_session_daemon
 *
 *  Yes, return 1
 *  No, return 0
 *  Error, return negative value
 */
int lttng_session_daemon_alive(void)
{
	int ret;

	ret = set_session_daemon_path();
	if (ret < 0) {
		/* Error */
		return ret;
	}

	/* If socket exist, we consider the daemon started */
	ret = access(sessiond_sock_path, F_OK);
	if (ret < 0) {
		/* Not alive */
		return 0;
	}

	/* Is alive */
	return 1;
}

/*
 * lib constructor
 */
static void __attribute__((constructor)) init()
{
	/* Set default session group */
	lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
}
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version 2
	7	* of the License, or (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write to the Free Software
	16	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	17	*/
	18
	19	#define _GNU_SOURCE
	20	#include <errno.h>
	21	#include <grp.h>
	22	#include <stdio.h>
	23	#include <stdlib.h>
	24	#include <string.h>
	25	#include <unistd.h>
	26
	27	#include <lttng/lttng.h>
	28
	29	#include "liblttsessiondcomm.h"
	30	#include "lttngerr.h"
	31	#include "lttng-share.h"
	32
	33	/* Socket to session daemon for communication */
	34	static int sessiond_socket;
	35	static char sessiond_sock_path[PATH_MAX];
	36
	37	/* Communication structure to ltt-sessiond */
	38	static struct lttcomm_session_msg lsm;
	39	static struct lttcomm_lttng_msg llm;
	40
	41	/* Variables */
	42	static char *tracing_group;
	43	static int connected;
	44
	45	/*
	46	* send_data_sessiond
	47	*
	48	* Send lttcomm_session_msg to the session daemon.
	49	*
	50	* On success, return 0
	51	* On error, return error code
	52	*/
	53	static int send_data_sessiond(void)
	54	{
	55	int ret;
	56
	57	if (!connected) {
	58	ret = -ENOTCONN;
	59	goto end;
	60	}
	61
	62	ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));
	63
	64	end:
	65	return ret;
	66	}
	67
	68	/*
	69	* recv_data_sessiond
	70	*
	71	* Receive data from the sessiond socket.
	72	*
	73	* On success, return 0
	74	* On error, return recv() error code
	75	*/
	76	static int recv_data_sessiond(void *buf, size_t len)
	77	{
	78	int ret;
	79
	80	if (!connected) {
	81	ret = -ENOTCONN;
	82	goto end;
	83	}
	84
	85	ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
	86
	87	end:
	88	return ret;
	89	}
	90
	91	/*
	92	* ask_sessiond
	93	*
	94	* Ask the session daemon a specific command and put the data into buf.
	95	*
	96	* Return size of data (only payload, not header).
	97	*/
	98	static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf)
	99	{
	100	int ret;
	101	size_t size;
	102	void *data = NULL;
	103
	104	ret = lttng_connect_sessiond();
	105	if (ret < 0) {
	106	goto end;
	107	}
	108
	109	lsm.cmd_type = lct;
	110
	111	/* Send command to session daemon */
	112	ret = send_data_sessiond();
	113	if (ret < 0) {
	114	goto end;
	115	}
	116
	117	/* Get header from data transmission */
	118	ret = recv_data_sessiond(&llm, sizeof(llm));
	119	if (ret < 0) {
	120	goto end;
	121	}
	122
	123	/* Check error code if OK */
	124	if (llm.ret_code != LTTCOMM_OK) {
	125	ret = -llm.ret_code;
	126	goto end;
	127	}
	128
	129	size = llm.data_size;
	130	if (size == 0) {
	131	goto end;
	132	}
	133
	134	data = (void*) malloc(size);
	135
	136	/* Get payload data */
	137	ret = recv_data_sessiond(data, size);
	138	if (ret < 0) {
	139	free(data);
	140	goto end;
	141	}
	142
	143	*buf = data;
	144	ret = size;
	145
	146	end:
	147	lttng_disconnect_sessiond();
	148	return ret;
	149	}
	150
	151	/*
	152	* check_tracing_group
	153	*
	154	* Check if the specified group name exist.
	155	* If yes, 0, else -1
	156	*/
	157	static int check_tracing_group(const char *grp_name)
	158	{
	159	struct group grp_tracing; / no free(). See getgrnam(3) */
	160	gid_t *grp_list;
	161	int grp_list_size, grp_id, i;
	162	int ret = -1;
	163
	164	/* Get GID of group 'tracing' */
	165	grp_tracing = getgrnam(grp_name);
	166	if (grp_tracing == NULL) {
	167	/* NULL means not found also. getgrnam(3) */
	168	if (errno != 0) {
	169	perror("getgrnam");
	170	}
	171	goto end;
	172	}
	173
	174	/* Get number of supplementary group IDs */
	175	grp_list_size = getgroups(0, NULL);
	176	if (grp_list_size < 0) {
	177	perror("getgroups");
	178	goto end;
	179	}
	180
	181	/* Alloc group list of the right size */
	182	grp_list = malloc(grp_list_size * sizeof(gid_t));
	183	grp_id = getgroups(grp_list_size, grp_list);
	184	if (grp_id < -1) {
	185	perror("getgroups");
	186	goto free_list;
	187	}
	188
	189	for (i = 0; i < grp_list_size; i++) {
	190	if (grp_list[i] == grp_tracing->gr_gid) {
	191	ret = 0;
	192	break;
	193	}
	194	}
	195
	196	free_list:
	197	free(grp_list);
	198
	199	end:
	200	return ret;
	201	}
	202
	203	/*
	204	* set_session_daemon_path
	205	*
	206	* Set sessiond socket path by putting it in
	207	* the global sessiond_sock_path variable.
	208	*/
	209	static int set_session_daemon_path(void)
	210	{
	211	int ret;
	212
	213	/* Are we in the tracing group ? */
	214	ret = check_tracing_group(tracing_group);
	215	if (ret < 0 && getuid() != 0) {
	216	if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
	217	getenv("HOME")) < 0) {
	218	return -ENOMEM;
	219	}
	220	} else {
	221	strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
	222	sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
	223	}
	224
	225	return 0;
	226	}
	227
	228	/*
	229	* lttng_start_tracing
	230	*
	231	* Start tracing for all trace of the session.
	232	*/
	233	int lttng_start_tracing(char *session_name)
	234	{
	235	strncpy(lsm.session_name, session_name, NAME_MAX);
	236	return ask_sessiond(LTTNG_START_TRACE, NULL);
	237	}
	238
	239	/*
	240	* lttng_stop_tracing
	241	*
	242	* Stop tracing for all trace of the session.
	243	*/
	244	int lttng_stop_tracing(char *session_name)
	245	{
	246	strncpy(lsm.session_name, session_name, NAME_MAX);
	247	return ask_sessiond(LTTNG_STOP_TRACE, NULL);
	248	}
	249
	250	/*
	251	* BEGIN Kernel control API
	252	*/
	253
	254	/*
	255	* lttng_kernel_add_context
	256	*/
	257	int lttng_kernel_add_context(struct lttng_kernel_context *ctx,
	258	char event_name, char channel_name)
	259	{
	260	if (channel_name != NULL) {
	261	strncpy(lsm.u.context.channel_name, channel_name, NAME_MAX);
	262	}
	263
	264	if (event_name != NULL) {
	265	strncpy(lsm.u.context.event_name, event_name, NAME_MAX);
	266	}
	267
	268	memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_kernel_context));
	269	return ask_sessiond(LTTNG_KERNEL_ADD_CONTEXT, NULL);
	270	}
	271
	272	/*
	273	* lttng_kernel_enable_event
	274	*/
	275	int lttng_kernel_enable_event(struct lttng_event ev, char channel_name)
	276	{
	277	int ret;
	278
	279	if (channel_name == NULL) {
	280	strncpy(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
	281	} else {
	282	strncpy(lsm.u.enable.channel_name, channel_name, NAME_MAX);
	283	}
	284
	285	if (ev == NULL) {
	286	ret = ask_sessiond(LTTNG_KERNEL_ENABLE_ALL_EVENT, NULL);
	287	} else {
	288	memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event));
	289	ret = ask_sessiond(LTTNG_KERNEL_ENABLE_EVENT, NULL);
	290	}
	291
	292	return ret;
	293	}
	294
	295	/*
	296	* lttng_kernel_disable_event
	297	*
	298	* Disable an event in the kernel tracer.
	299	*/
	300	int lttng_kernel_disable_event(char name, char channel_name)
	301	{
	302	int ret;
	303
	304	if (channel_name == NULL) {
	305	strncpy(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
	306	} else {
	307	strncpy(lsm.u.disable.channel_name, channel_name, NAME_MAX);
	308	}
	309
	310	if (name == NULL) {
	311	ret = ask_sessiond(LTTNG_KERNEL_DISABLE_ALL_EVENT, NULL);
	312	} else {
	313	strncpy(lsm.u.disable.name, name, NAME_MAX);
	314	ret = ask_sessiond(LTTNG_KERNEL_DISABLE_EVENT, NULL);
	315	}
	316
	317	return ret;
	318	}
	319
	320	/*
	321	* lttng_kernel_enable_channel
	322	*
	323	* Enable recording for a channel for the kernel tracer.
	324	*/
	325	int lttng_kernel_enable_channel(char *name)
	326	{
	327	strncpy(lsm.u.enable.channel_name, name, NAME_MAX);
	328	return ask_sessiond(LTTNG_KERNEL_ENABLE_CHANNEL, NULL);
	329	}
	330
	331	/*
	332	* lttng_kernel_disable_channel
	333	*
	334	* Disable recording for the channel for the kernel tracer.
	335	*/
	336	int lttng_kernel_disable_channel(char *name)
	337	{
	338	strncpy(lsm.u.disable.channel_name, name, NAME_MAX);
	339	return ask_sessiond(LTTNG_KERNEL_DISABLE_CHANNEL, NULL);
	340	}
	341
	342	/*
	343	* lttng_kernel_create_channel
	344	*
	345	* Create a channel in the kernel tracer.
	346	*/
	347	int lttng_kernel_create_channel(struct lttng_channel *chan)
	348	{
	349	memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));
	350	return ask_sessiond(LTTNG_KERNEL_CREATE_CHANNEL, NULL);
	351	}
	352
	353	/*
	354	* lttng_list_events
	355	*
	356	* List all available events in the kernel.
	357	*
	358	* Return the size (bytes) of the list and set the event_list array.
	359	* On error, return negative value.
	360	*/
	361	int lttng_kernel_list_events(char **event_list)
	362	{
	363	return ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) event_list);
	364	}
	365
	366	/*
	367	* END Kernel control API
	368	*/
	369
	370	/*
	371	* lttng_get_readable_code
	372	*
	373	* Return a human readable string of code
	374	*/
	375	const char *lttng_get_readable_code(int code)
	376	{
	377	if (code > -LTTCOMM_OK) {
	378	return "Ended with errors";
	379	}
	380
	381	return lttcomm_get_readable_code(code);
	382	}
	383
	384	/*
	385	* lttng_ust_list_apps
	386	*
	387	* Ask the session daemon for all UST traceable applications.
	388	*
	389	* Return the number of pids.
	390	* On error, return negative value.
	391	*/
	392	int lttng_ust_list_traceable_apps(pid_t **pids)
	393	{
	394	int ret;
	395
	396	ret = ask_sessiond(LTTNG_LIST_TRACEABLE_APPS, (void**) pids);
	397	if (ret < 0) {
	398	return ret;
	399	}
	400
	401	return ret / sizeof(pid_t);
	402	}
	403
	404	/*
	405	* lttng_list_traces
	406	*
	407	* Ask the session daemon for all traces (kernel and ust) for the session
	408	* identified by name.
	409	*
	410	* Return the number of traces.
	411	* On error, return negative value.
	412	*/
	413	/*
	414	int lttng_list_traces(char session_name, struct lttng_trace *traces)
	415	{
	416	int ret;
	417
	418	strncpy(lsm.session_name, session_name, NAME_MAX);
	419
	420	ret = ask_sessiond(LTTNG_LIST_TRACES, (void **) traces);
	421	if (ret < 0) {
	422	return ret;
	423	}
	424
	425	return ret / sizeof(struct lttng_trace);
	426	}
	427	*/
	428
	429	/*
	430	* lttng_create_session
	431	*
	432	* Create a brand new session using name.
	433	*/
	434	int lttng_create_session(char name, char path)
	435	{
	436	strncpy(lsm.session_name, name, NAME_MAX);
	437	strncpy(lsm.path, path, PATH_MAX);
	438	return ask_sessiond(LTTNG_CREATE_SESSION, NULL);
	439	}
	440
	441	/*
	442	* lttng_destroy_session
	443	*
	444	* Destroy session using name.
	445	*/
	446	int lttng_destroy_session(char *name)
	447	{
	448	strncpy(lsm.session_name, name, NAME_MAX);
	449	return ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
	450	}
	451
	452	/*
	453	* lttng_list_sessions
	454	*
	455	* Ask the session daemon for all available sessions.
	456	*
	457	* Return number of session.
	458	* On error, return negative value.
	459	*/
	460	int lttng_list_sessions(struct lttng_session **sessions)
	461	{
	462	int ret;
	463
	464	ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
	465	if (ret < 0) {
	466	return ret;
	467	}
	468
	469	return ret / sizeof(struct lttng_session);
	470	}
	471
	472	/*
	473	* lttng_connect_sessiond
	474	*
	475	* Connect to the LTTng session daemon.
	476	* On success, return 0
	477	* On error, return a negative value
	478	*/
	479	int lttng_connect_sessiond(void)
	480	{
	481	int ret;
	482
	483	ret = set_session_daemon_path();
	484	if (ret < 0) {
	485	return ret;
	486	}
	487
	488	/* Connect to the sesssion daemon */
	489	ret = lttcomm_connect_unix_sock(sessiond_sock_path);
	490	if (ret < 0) {
	491	return ret;
	492	}
	493
	494	sessiond_socket = ret;
	495	connected = 1;
	496
	497	return 0;
	498	}
	499
	500	/*
	501	* lttng_disconnect_sessiond
	502	*
	503	* Clean disconnect the session daemon.
	504	*/
	505	int lttng_disconnect_sessiond(void)
	506	{
	507	int ret = 0;
	508
	509	if (connected) {
	510	ret = lttcomm_close_unix_sock(sessiond_socket);
	511	sessiond_socket = 0;
	512	connected = 0;
	513	}
	514
	515	return ret;
	516	}
	517
	518	void lttng_set_session_name(char *name)
	519	{
	520	strncpy(lsm.session_name, name, NAME_MAX);
	521	}
	522
	523	/*
	524	* lttng_set_tracing_group
	525	*
	526	* Set tracing group variable with name. This function
	527	* allocate memory pointed by tracing_group.
	528	*/
	529	int lttng_set_tracing_group(const char *name)
	530	{
	531	if (asprintf(&tracing_group, "%s", name) < 0) {
	532	return -ENOMEM;
	533	}
	534
	535	return 0;
	536	}
	537
	538	/*
	539	* lttng_check_session_daemon
	540	*
	541	* Yes, return 1
	542	* No, return 0
	543	* Error, return negative value
	544	*/
	545	int lttng_session_daemon_alive(void)
	546	{
	547	int ret;
	548
	549	ret = set_session_daemon_path();
	550	if (ret < 0) {
	551	/* Error */
	552	return ret;
	553	}
	554
	555	/* If socket exist, we consider the daemon started */
	556	ret = access(sessiond_sock_path, F_OK);
	557	if (ret < 0) {
	558	/* Not alive */
	559	return 0;
	560	}
	561
	562	/* Is alive */
	563	return 1;
	564	}
	565
	566	/*
	567	* lib constructor
	568	*/
	569	static void __attribute__((constructor)) init()
	570	{
	571	/* Set default session group */
	572	lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
	573	}