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

/*
 * liblttngctl.c
 *
 * Linux Trace Toolkit Control Library
 *
 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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;
}

/*
 *  Check if the specified group name exist.
 *
 *  If yes return 0, else return -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 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;
}

/*
 *  Connect to the LTTng session daemon.
 *
 *  On success, return 0. On error, return -1.
 */
static int 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;
}

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

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

	return ret;
}

/*
 * Reset the session message structure.
 */
static void reset_session_msg(void)
{
	memset(&lsm, 0, sizeof(struct lttcomm_session_msg));
}

/*
 *  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 = 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) {
		ret = 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:
	disconnect_sessiond();
	reset_session_msg();
	return ret;
}

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

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

/*
 *  lttng_add_context
 */
int lttng_add_context(struct lttng_domain *domain,
		struct lttng_event_context *ctx, const char *event_name,
		const char *channel_name)
{
	int ret;

	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_event_context));

	switch (domain->type) {
	case LTTNG_DOMAIN_KERNEL:
		ret = ask_sessiond(LTTNG_KERNEL_ADD_CONTEXT, NULL);
		break;
	case LTTNG_DOMAIN_UST:
		ret = LTTCOMM_NOT_IMPLEMENTED;
		break;
	default:
		ret = LTTCOMM_UNKNOWN_DOMAIN;
		break;
	};

	return ret;
}

/*
 *  lttng_enable_event
 */
int lttng_enable_event(struct lttng_domain *domain,
		struct lttng_event *ev, const 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);
	}

	switch (domain->type) {
		case LTTNG_DOMAIN_KERNEL:
			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);
			}
			break;
		case LTTNG_DOMAIN_UST:
			ret = LTTCOMM_NOT_IMPLEMENTED;
			break;
		default:
			ret = LTTCOMM_UNKNOWN_DOMAIN;
			break;
	};

	return ret;
}

/*
 * Disable an event in the kernel tracer.
 */
int lttng_disable_event(struct lttng_domain *domain, const char *name,
		const 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);
	}

	switch (domain->type) {
		case LTTNG_DOMAIN_KERNEL:
			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);
			}
			break;
		case LTTNG_DOMAIN_UST:
			ret = LTTCOMM_NOT_IMPLEMENTED;
			break;
		default:
			ret = LTTCOMM_UNKNOWN_DOMAIN;
			break;
	};

	return ret;
}

/*
 * Enable recording for a channel for the kernel tracer.
 */
int lttng_enable_channel(struct lttng_domain *domain,
		struct lttng_channel *chan)
{
	int ret;

	memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));

	switch (domain->type) {
		case LTTNG_DOMAIN_KERNEL:
			ret = ask_sessiond(LTTNG_KERNEL_ENABLE_CHANNEL, NULL);
			break;
		case LTTNG_DOMAIN_UST:
			ret = LTTCOMM_NOT_IMPLEMENTED;
			break;
		default:
			ret = LTTCOMM_UNKNOWN_DOMAIN;
			break;
	};

	return ret;
}

/*
 * Disable recording for the channel for the kernel tracer.
 */
int lttng_disable_channel(struct lttng_domain *domain, const char *name)
{
	int ret;

	strncpy(lsm.u.disable.channel_name, name, NAME_MAX);

	switch (domain->type) {
		case LTTNG_DOMAIN_KERNEL:
			ret = ask_sessiond(LTTNG_KERNEL_DISABLE_CHANNEL, NULL);
			break;
		case LTTNG_DOMAIN_UST:
			ret = LTTCOMM_NOT_IMPLEMENTED;
			break;
		default:
			ret = LTTCOMM_UNKNOWN_DOMAIN;
			break;
	};

	return ret;
}

/*
 * 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_list_events(struct lttng_domain *domain, char **event_list)
{
	int ret;

	switch (domain->type) {
		case LTTNG_DOMAIN_KERNEL:
			ret = ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) event_list);
			break;
		case LTTNG_DOMAIN_UST:
			ret = LTTCOMM_NOT_IMPLEMENTED;
			break;
		default:
			ret = LTTCOMM_UNKNOWN_DOMAIN;
			break;
	};

	return ret;
}

/*
 *  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);
}

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

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

/*
 *  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);
}

/*
 * Set session name for the current lsm.
 */
void lttng_set_session_name(const 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	* liblttngctl.c
	3	*
	4	* Linux Trace Toolkit Control Library
	5	*
	6	* Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	21	*/
	22
	23	#define _GNU_SOURCE
	24	#include <errno.h>
	25	#include <grp.h>
	26	#include <stdio.h>
	27	#include <stdlib.h>
	28	#include <string.h>
	29	#include <unistd.h>
	30
	31	#include <lttng/lttng.h>
	32
	33	#include "liblttsessiondcomm.h"
	34	#include "lttngerr.h"
	35	#include "lttng-share.h"
	36
	37	/* Socket to session daemon for communication */
	38	static int sessiond_socket;
	39	static char sessiond_sock_path[PATH_MAX];
	40
	41	/* Communication structure to ltt-sessiond */
	42	static struct lttcomm_session_msg lsm;
	43	static struct lttcomm_lttng_msg llm;
	44
	45	/* Variables */
	46	static char *tracing_group;
	47	static int connected;
	48
	49	/*
	50	* send_data_sessiond
	51	*
	52	* Send lttcomm_session_msg to the session daemon.
	53	*
	54	* On success, return 0
	55	* On error, return error code
	56	*/
	57	static int send_data_sessiond(void)
	58	{
	59	int ret;
	60
	61	if (!connected) {
	62	ret = -ENOTCONN;
	63	goto end;
	64	}
	65
	66	ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));
	67
	68	end:
	69	return ret;
	70	}
	71
	72	/*
	73	* recv_data_sessiond
	74	*
	75	* Receive data from the sessiond socket.
	76	*
	77	* On success, return 0
	78	* On error, return recv() error code
	79	*/
	80	static int recv_data_sessiond(void *buf, size_t len)
	81	{
	82	int ret;
	83
	84	if (!connected) {
	85	ret = -ENOTCONN;
	86	goto end;
	87	}
	88
	89	ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
	90
	91	end:
	92	return ret;
	93	}
	94
	95	/*
	96	* Check if the specified group name exist.
	97	*
	98	* If yes return 0, else return -1.
	99	*/
	100	static int check_tracing_group(const char *grp_name)
	101	{
	102	struct group grp_tracing; / no free(). See getgrnam(3) */
	103	gid_t *grp_list;
	104	int grp_list_size, grp_id, i;
	105	int ret = -1;
	106
	107	/* Get GID of group 'tracing' */
	108	grp_tracing = getgrnam(grp_name);
	109	if (grp_tracing == NULL) {
	110	/* NULL means not found also. getgrnam(3) */
	111	if (errno != 0) {
	112	perror("getgrnam");
	113	}
	114	goto end;
	115	}
	116
	117	/* Get number of supplementary group IDs */
	118	grp_list_size = getgroups(0, NULL);
	119	if (grp_list_size < 0) {
	120	perror("getgroups");
	121	goto end;
	122	}
	123
	124	/* Alloc group list of the right size */
	125	grp_list = malloc(grp_list_size * sizeof(gid_t));
	126	grp_id = getgroups(grp_list_size, grp_list);
	127	if (grp_id < -1) {
	128	perror("getgroups");
	129	goto free_list;
	130	}
	131
	132	for (i = 0; i < grp_list_size; i++) {
	133	if (grp_list[i] == grp_tracing->gr_gid) {
	134	ret = 0;
	135	break;
	136	}
	137	}
	138
	139	free_list:
	140	free(grp_list);
	141
	142	end:
	143	return ret;
	144	}
	145
	146	/*
	147	* Set sessiond socket path by putting it in the global sessiond_sock_path
	148	* variable.
	149	*/
	150	static int set_session_daemon_path(void)
	151	{
	152	int ret;
	153
	154	/* Are we in the tracing group ? */
	155	ret = check_tracing_group(tracing_group);
	156	if (ret < 0 && getuid() != 0) {
	157	if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
	158	getenv("HOME")) < 0) {
	159	return -ENOMEM;
	160	}
	161	} else {
	162	strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
	163	sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
	164	}
	165
	166	return 0;
	167	}
	168
	169	/*
	170	* Connect to the LTTng session daemon.
	171	*
	172	* On success, return 0. On error, return -1.
	173	*/
	174	static int connect_sessiond(void)
	175	{
	176	int ret;
	177
	178	ret = set_session_daemon_path();
	179	if (ret < 0) {
	180	return ret;
	181	}
	182
	183	/* Connect to the sesssion daemon */
	184	ret = lttcomm_connect_unix_sock(sessiond_sock_path);
	185	if (ret < 0) {
	186	return ret;
	187	}
	188
	189	sessiond_socket = ret;
	190	connected = 1;
	191
	192	return 0;
	193	}
	194
	195	/*
	196	* Clean disconnect the session daemon.
	197	*/
	198	static int disconnect_sessiond(void)
	199	{
	200	int ret = 0;
	201
	202	if (connected) {
	203	ret = lttcomm_close_unix_sock(sessiond_socket);
	204	sessiond_socket = 0;
	205	connected = 0;
	206	}
	207
	208	return ret;
	209	}
	210
	211	/*
	212	* Reset the session message structure.
	213	*/
	214	static void reset_session_msg(void)
	215	{
	216	memset(&lsm, 0, sizeof(struct lttcomm_session_msg));
	217	}
	218
	219	/*
	220	* ask_sessiond
	221	*
	222	* Ask the session daemon a specific command and put the data into buf.
	223	*
	224	* Return size of data (only payload, not header).
	225	*/
	226	static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf)
	227	{
	228	int ret;
	229	size_t size;
	230	void *data = NULL;
	231
	232	ret = connect_sessiond();
	233	if (ret < 0) {
	234	goto end;
	235	}
	236
	237	lsm.cmd_type = lct;
	238
	239	/* Send command to session daemon */
	240	ret = send_data_sessiond();
	241	if (ret < 0) {
	242	goto end;
	243	}
	244
	245	/* Get header from data transmission */
	246	ret = recv_data_sessiond(&llm, sizeof(llm));
	247	if (ret < 0) {
	248	goto end;
	249	}
	250
	251	/* Check error code if OK */
	252	if (llm.ret_code != LTTCOMM_OK) {
	253	ret = -llm.ret_code;
	254	goto end;
	255	}
	256
	257	size = llm.data_size;
	258	if (size == 0) {
	259	ret = 0;
	260	goto end;
	261	}
	262
	263	data = (void*) malloc(size);
	264
	265	/* Get payload data */
	266	ret = recv_data_sessiond(data, size);
	267	if (ret < 0) {
	268	free(data);
	269	goto end;
	270	}
	271
	272	*buf = data;
	273	ret = size;
	274
	275	end:
	276	disconnect_sessiond();
	277	reset_session_msg();
	278	return ret;
	279	}
	280
	281	/*
	282	* Start tracing for all trace of the session.
	283	*/
	284	int lttng_start_tracing(const char *session_name)
	285	{
	286	strncpy(lsm.session_name, session_name, NAME_MAX);
	287	return ask_sessiond(LTTNG_START_TRACE, NULL);
	288	}
	289
	290	/*
	291	* Stop tracing for all trace of the session.
	292	*/
	293	int lttng_stop_tracing(const char *session_name)
	294	{
	295	strncpy(lsm.session_name, session_name, NAME_MAX);
	296	return ask_sessiond(LTTNG_STOP_TRACE, NULL);
	297	}
	298
	299	/*
	300	* lttng_add_context
	301	*/
	302	int lttng_add_context(struct lttng_domain *domain,
	303	struct lttng_event_context ctx, const char event_name,
	304	const char *channel_name)
	305	{
	306	int ret;
	307
	308	if (channel_name != NULL) {
	309	strncpy(lsm.u.context.channel_name, channel_name, NAME_MAX);
	310	}
	311
	312	if (event_name != NULL) {
	313	strncpy(lsm.u.context.event_name, event_name, NAME_MAX);
	314	}
	315
	316	memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
	317
	318	switch (domain->type) {
	319	case LTTNG_DOMAIN_KERNEL:
	320	ret = ask_sessiond(LTTNG_KERNEL_ADD_CONTEXT, NULL);
	321	break;
	322	case LTTNG_DOMAIN_UST:
	323	ret = LTTCOMM_NOT_IMPLEMENTED;
	324	break;
	325	default:
	326	ret = LTTCOMM_UNKNOWN_DOMAIN;
	327	break;
	328	};
	329
	330	return ret;
	331	}
	332
	333	/*
	334	* lttng_enable_event
	335	*/
	336	int lttng_enable_event(struct lttng_domain *domain,
	337	struct lttng_event ev, const char channel_name)
	338	{
	339	int ret;
	340
	341	if (channel_name == NULL) {
	342	strncpy(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
	343	} else {
	344	strncpy(lsm.u.enable.channel_name, channel_name, NAME_MAX);
	345	}
	346
	347	switch (domain->type) {
	348	case LTTNG_DOMAIN_KERNEL:
	349	if (ev == NULL) {
	350	ret = ask_sessiond(LTTNG_KERNEL_ENABLE_ALL_EVENT, NULL);
	351	} else {
	352	memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event));
	353	ret = ask_sessiond(LTTNG_KERNEL_ENABLE_EVENT, NULL);
	354	}
	355	break;
	356	case LTTNG_DOMAIN_UST:
	357	ret = LTTCOMM_NOT_IMPLEMENTED;
	358	break;
	359	default:
	360	ret = LTTCOMM_UNKNOWN_DOMAIN;
	361	break;
	362	};
	363
	364	return ret;
	365	}
	366
	367	/*
	368	* Disable an event in the kernel tracer.
	369	*/
	370	int lttng_disable_event(struct lttng_domain domain, const char name,
	371	const char *channel_name)
	372	{
	373	int ret;
	374
	375	if (channel_name == NULL) {
	376	strncpy(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
	377	} else {
	378	strncpy(lsm.u.disable.channel_name, channel_name, NAME_MAX);
	379	}
	380
	381	switch (domain->type) {
	382	case LTTNG_DOMAIN_KERNEL:
	383	if (name == NULL) {
	384	ret = ask_sessiond(LTTNG_KERNEL_DISABLE_ALL_EVENT, NULL);
	385	} else {
	386	strncpy(lsm.u.disable.name, name, NAME_MAX);
	387	ret = ask_sessiond(LTTNG_KERNEL_DISABLE_EVENT, NULL);
	388	}
	389	break;
	390	case LTTNG_DOMAIN_UST:
	391	ret = LTTCOMM_NOT_IMPLEMENTED;
	392	break;
	393	default:
	394	ret = LTTCOMM_UNKNOWN_DOMAIN;
	395	break;
	396	};
	397
	398	return ret;
	399	}
	400
	401	/*
	402	* Enable recording for a channel for the kernel tracer.
	403	*/
	404	int lttng_enable_channel(struct lttng_domain *domain,
	405	struct lttng_channel *chan)
	406	{
	407	int ret;
	408
	409	memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));
	410
	411	switch (domain->type) {
	412	case LTTNG_DOMAIN_KERNEL:
	413	ret = ask_sessiond(LTTNG_KERNEL_ENABLE_CHANNEL, NULL);
	414	break;
	415	case LTTNG_DOMAIN_UST:
	416	ret = LTTCOMM_NOT_IMPLEMENTED;
	417	break;
	418	default:
	419	ret = LTTCOMM_UNKNOWN_DOMAIN;
	420	break;
	421	};
	422
	423	return ret;
	424	}
	425
	426	/*
	427	* Disable recording for the channel for the kernel tracer.
	428	*/
	429	int lttng_disable_channel(struct lttng_domain domain, const char name)
	430	{
	431	int ret;
	432
	433	strncpy(lsm.u.disable.channel_name, name, NAME_MAX);
	434
	435	switch (domain->type) {
	436	case LTTNG_DOMAIN_KERNEL:
	437	ret = ask_sessiond(LTTNG_KERNEL_DISABLE_CHANNEL, NULL);
	438	break;
	439	case LTTNG_DOMAIN_UST:
	440	ret = LTTCOMM_NOT_IMPLEMENTED;
	441	break;
	442	default:
	443	ret = LTTCOMM_UNKNOWN_DOMAIN;
	444	break;
	445	};
	446
	447	return ret;
	448	}
	449
	450	/*
	451	* List all available events in the kernel.
	452	*
	453	* Return the size (bytes) of the list and set the event_list array.
	454	* On error, return negative value.
	455	*/
	456	int lttng_list_events(struct lttng_domain domain, char *event_list)
	457	{
	458	int ret;
	459
	460	switch (domain->type) {
	461	case LTTNG_DOMAIN_KERNEL:
	462	ret = ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) event_list);
	463	break;
	464	case LTTNG_DOMAIN_UST:
	465	ret = LTTCOMM_NOT_IMPLEMENTED;
	466	break;
	467	default:
	468	ret = LTTCOMM_UNKNOWN_DOMAIN;
	469	break;
	470	};
	471
	472	return ret;
	473	}
	474
	475	/*
	476	* Return a human readable string of code
	477	*/
	478	const char *lttng_get_readable_code(int code)
	479	{
	480	if (code > -LTTCOMM_OK) {
	481	return "Ended with errors";
	482	}
	483
	484	return lttcomm_get_readable_code(code);
	485	}
	486
	487	/*
	488	* Create a brand new session using name.
	489	*/
	490	int lttng_create_session(const char name, const char path)
	491	{
	492	strncpy(lsm.session_name, name, NAME_MAX);
	493	strncpy(lsm.path, path, PATH_MAX);
	494	return ask_sessiond(LTTNG_CREATE_SESSION, NULL);
	495	}
	496
	497	/*
	498	* Destroy session using name.
	499	*/
	500	int lttng_destroy_session(const char *name)
	501	{
	502	strncpy(lsm.session_name, name, NAME_MAX);
	503	return ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
	504	}
	505
	506	/*
	507	* Ask the session daemon for all available sessions.
	508	*
	509	* Return number of session.
	510	* On error, return negative value.
	511	*/
	512	int lttng_list_sessions(struct lttng_session **sessions)
	513	{
	514	int ret;
	515
	516	ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
	517	if (ret < 0) {
	518	return ret;
	519	}
	520
	521	return ret / sizeof(struct lttng_session);
	522	}
	523
	524	/*
	525	* Set session name for the current lsm.
	526	*/
	527	void lttng_set_session_name(const char *name)
	528	{
	529	strncpy(lsm.session_name, name, NAME_MAX);
	530	}
	531
	532	/*
	533	* lttng_set_tracing_group
	534	*
	535	* Set tracing group variable with name. This function
	536	* allocate memory pointed by tracing_group.
	537	*/
	538	int lttng_set_tracing_group(const char *name)
	539	{
	540	if (asprintf(&tracing_group, "%s", name) < 0) {
	541	return -ENOMEM;
	542	}
	543
	544	return 0;
	545	}
	546
	547	/*
	548	* lttng_check_session_daemon
	549	*
	550	* Yes, return 1
	551	* No, return 0
	552	* Error, return negative value
	553	*/
	554	int lttng_session_daemon_alive(void)
	555	{
	556	int ret;
	557
	558	ret = set_session_daemon_path();
	559	if (ret < 0) {
	560	/* Error */
	561	return ret;
	562	}
	563
	564	/* If socket exist, we consider the daemon started */
	565	ret = access(sessiond_sock_path, F_OK);
	566	if (ret < 0) {
	567	/* Not alive */
	568	return 0;
	569	}
	570
	571	/* Is alive */
	572	return 1;
	573	}
	574
	575	/*
	576	* lib constructor
	577	*/
	578	static void __attribute__((constructor)) init()
	579	{
	580	/* Set default session group */
	581	lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
	582	}