4 * Linux Trace Toolkit Control Library
6 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
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.
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.
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
31 #include <lttng-sessiond-comm.h>
32 #include <lttng-share.h>
33 #include <lttng/lttng.h>
36 /* Socket to session daemon for communication */
37 static int sessiond_socket
;
38 static char sessiond_sock_path
[PATH_MAX
];
41 static char *tracing_group
;
45 * Copy string from src to dst and enforce null terminated byte.
47 static void copy_string(char *dst
, const char *src
, size_t len
)
50 strncpy(dst
, src
, len
);
51 /* Enforce the NULL terminated byte */
59 * Copy domain to lttcomm_session_msg domain.
61 * If domain is unknown, default domain will be the kernel.
63 static void copy_lttng_domain(struct lttng_domain
*dst
, struct lttng_domain
*src
)
67 case LTTNG_DOMAIN_KERNEL
:
68 case LTTNG_DOMAIN_UST
:
69 case LTTNG_DOMAIN_UST_EXEC_NAME
:
70 case LTTNG_DOMAIN_UST_PID
:
71 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN
:
72 memcpy(dst
, src
, sizeof(struct lttng_domain
));
75 dst
->type
= LTTNG_DOMAIN_KERNEL
;
82 * Send lttcomm_session_msg to the session daemon.
84 * On success, return 0
85 * On error, return error code
87 static int send_session_msg(struct lttcomm_session_msg
*lsm
)
96 ret
= lttcomm_send_unix_sock(sessiond_socket
, lsm
,
97 sizeof(struct lttcomm_session_msg
));
104 * Receive data from the sessiond socket.
106 * On success, return 0
107 * On error, return recv() error code
109 static int recv_data_sessiond(void *buf
, size_t len
)
118 ret
= lttcomm_recv_unix_sock(sessiond_socket
, buf
, len
);
125 * Check if the specified group name exist.
127 * If yes return 1, else return -1.
129 static int check_tracing_group(const char *grp_name
)
131 struct group
*grp_tracing
; /* no free(). See getgrnam(3) */
133 int grp_list_size
, grp_id
, i
;
136 /* Get GID of group 'tracing' */
137 grp_tracing
= getgrnam(grp_name
);
138 if (grp_tracing
== NULL
) {
139 /* NULL means not found also. getgrnam(3) */
146 /* Get number of supplementary group IDs */
147 grp_list_size
= getgroups(0, NULL
);
148 if (grp_list_size
< 0) {
153 /* Alloc group list of the right size */
154 grp_list
= malloc(grp_list_size
* sizeof(gid_t
));
159 grp_id
= getgroups(grp_list_size
, grp_list
);
165 for (i
= 0; i
< grp_list_size
; i
++) {
166 if (grp_list
[i
] == grp_tracing
->gr_gid
) {
180 * Try connect to session daemon with sock_path.
182 * Return 0 on success, else -1
184 static int try_connect_sessiond(const char *sock_path
)
188 /* If socket exist, we check if the daemon listens for connect. */
189 ret
= access(sock_path
, F_OK
);
195 ret
= lttcomm_connect_unix_sock(sock_path
);
201 ret
= lttcomm_close_unix_sock(ret
);
203 perror("lttcomm_close_unix_sock");
210 * Set sessiond socket path by putting it in the global sessiond_sock_path
213 static int set_session_daemon_path(void)
216 int in_tgroup
= 0; /* In tracing group */
222 /* Are we in the tracing group ? */
223 in_tgroup
= check_tracing_group(tracing_group
);
228 copy_string(sessiond_sock_path
,
229 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK
,
230 sizeof(sessiond_sock_path
));
231 } else if (in_tgroup
) {
233 copy_string(sessiond_sock_path
,
234 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK
,
235 sizeof(sessiond_sock_path
));
237 ret
= try_connect_sessiond(sessiond_sock_path
);
239 /* Global session daemon not available */
240 if (snprintf(sessiond_sock_path
, sizeof(sessiond_sock_path
),
241 DEFAULT_HOME_CLIENT_UNIX_SOCK
,
242 getenv("HOME")) < 0) {
247 /* Not in tracing group and not root, default */
248 if (snprintf(sessiond_sock_path
, PATH_MAX
,
249 DEFAULT_HOME_CLIENT_UNIX_SOCK
,
250 getenv("HOME")) < 0) {
259 * Connect to the LTTng session daemon.
261 * On success, return 0. On error, return -1.
263 static int connect_sessiond(void)
267 ret
= set_session_daemon_path();
272 /* Connect to the sesssion daemon */
273 ret
= lttcomm_connect_unix_sock(sessiond_sock_path
);
278 sessiond_socket
= ret
;
285 * Clean disconnect the session daemon.
287 static int disconnect_sessiond(void)
292 ret
= lttcomm_close_unix_sock(sessiond_socket
);
301 * Ask the session daemon a specific command and put the data into buf.
303 * Return size of data (only payload, not header).
305 static int ask_sessiond(struct lttcomm_session_msg
*lsm
, void **buf
)
310 struct lttcomm_lttng_msg llm
;
312 ret
= connect_sessiond();
317 /* Send command to session daemon */
318 ret
= send_session_msg(lsm
);
323 /* Get header from data transmission */
324 ret
= recv_data_sessiond(&llm
, sizeof(llm
));
329 /* Check error code if OK */
330 if (llm
.ret_code
!= LTTCOMM_OK
) {
335 size
= llm
.data_size
;
337 /* If client free with size 0 */
343 data
= (void*) malloc(size
);
345 /* Get payload data */
346 ret
= recv_data_sessiond(data
, size
);
353 * Extra protection not to dereference a NULL pointer. If buf is NULL at
354 * this point, an error is returned and data is freed.
366 disconnect_sessiond();
371 * Create lttng handle and return pointer.
373 struct lttng_handle
*lttng_create_handle(const char *session_name
,
374 struct lttng_domain
*domain
)
376 struct lttng_handle
*handle
;
378 handle
= malloc(sizeof(struct lttng_handle
));
379 if (handle
== NULL
) {
380 perror("malloc handle");
384 /* Copy session name */
385 copy_string(handle
->session_name
, session_name
,
386 sizeof(handle
->session_name
));
388 /* Copy lttng domain */
389 copy_lttng_domain(&handle
->domain
, domain
);
396 * Destroy handle by free(3) the pointer.
398 void lttng_destroy_handle(struct lttng_handle
*handle
)
406 * Register an outside consumer.
408 int lttng_register_consumer(struct lttng_handle
*handle
,
409 const char *socket_path
)
411 struct lttcomm_session_msg lsm
;
413 lsm
.cmd_type
= LTTNG_REGISTER_CONSUMER
;
414 copy_string(lsm
.session
.name
, handle
->session_name
,
415 sizeof(lsm
.session
.name
));
416 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
418 copy_string(lsm
.u
.reg
.path
, socket_path
, sizeof(lsm
.u
.reg
.path
));
420 return ask_sessiond(&lsm
, NULL
);
424 * Start tracing for all trace of the session.
426 int lttng_start_tracing(struct lttng_handle
*handle
)
428 struct lttcomm_session_msg lsm
;
434 lsm
.cmd_type
= LTTNG_START_TRACE
;
435 copy_string(lsm
.session
.name
, handle
->session_name
,
436 sizeof(lsm
.session
.name
));
438 return ask_sessiond(&lsm
, NULL
);
442 * Stop tracing for all trace of the session.
444 int lttng_stop_tracing(struct lttng_handle
*handle
)
446 struct lttcomm_session_msg lsm
;
448 lsm
.cmd_type
= LTTNG_STOP_TRACE
;
449 copy_string(lsm
.session
.name
, handle
->session_name
,
450 sizeof(lsm
.session
.name
));
452 return ask_sessiond(&lsm
, NULL
);
456 * Add context to event or/and channel.
458 int lttng_add_context(struct lttng_handle
*handle
,
459 struct lttng_event_context
*ctx
, const char *event_name
,
460 const char *channel_name
)
462 struct lttcomm_session_msg lsm
;
468 lsm
.cmd_type
= LTTNG_ADD_CONTEXT
;
470 /* Copy channel name */
471 copy_string(lsm
.u
.context
.channel_name
, channel_name
,
472 sizeof(lsm
.u
.context
.channel_name
));
473 /* Copy event name */
474 copy_string(lsm
.u
.context
.event_name
, event_name
,
475 sizeof(lsm
.u
.context
.event_name
));
477 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
480 memcpy(&lsm
.u
.context
.ctx
, ctx
, sizeof(struct lttng_event_context
));
483 copy_string(lsm
.session
.name
, handle
->session_name
,
484 sizeof(lsm
.session
.name
));
486 return ask_sessiond(&lsm
, NULL
);
492 int lttng_enable_event(struct lttng_handle
*handle
,
493 struct lttng_event
*ev
, const char *channel_name
)
495 struct lttcomm_session_msg lsm
;
497 if (!handle
|| ev
== NULL
) {
501 if (channel_name
== NULL
) {
502 copy_string(lsm
.u
.enable
.channel_name
, DEFAULT_CHANNEL_NAME
,
503 sizeof(lsm
.u
.enable
.channel_name
));
505 copy_string(lsm
.u
.enable
.channel_name
, channel_name
,
506 sizeof(lsm
.u
.enable
.channel_name
));
509 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
511 if (ev
->name
[0] != '\0') {
512 lsm
.cmd_type
= LTTNG_ENABLE_EVENT
;
514 lsm
.cmd_type
= LTTNG_ENABLE_ALL_EVENT
;
516 memcpy(&lsm
.u
.enable
.event
, ev
, sizeof(lsm
.u
.enable
.event
));
518 copy_string(lsm
.session
.name
, handle
->session_name
,
519 sizeof(lsm
.session
.name
));
521 return ask_sessiond(&lsm
, NULL
);
525 * Disable event of a channel and domain.
527 int lttng_disable_event(struct lttng_handle
*handle
, const char *name
,
528 const char *channel_name
)
530 struct lttcomm_session_msg lsm
;
537 copy_string(lsm
.u
.disable
.channel_name
, channel_name
,
538 sizeof(lsm
.u
.disable
.channel_name
));
540 copy_string(lsm
.u
.disable
.channel_name
, DEFAULT_CHANNEL_NAME
,
541 sizeof(lsm
.u
.disable
.channel_name
));
544 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
547 copy_string(lsm
.u
.disable
.name
, name
, sizeof(lsm
.u
.disable
.name
));
548 lsm
.cmd_type
= LTTNG_DISABLE_EVENT
;
550 lsm
.cmd_type
= LTTNG_DISABLE_ALL_EVENT
;
553 copy_string(lsm
.session
.name
, handle
->session_name
,
554 sizeof(lsm
.session
.name
));
556 return ask_sessiond(&lsm
, NULL
);
560 * Enable channel per domain
562 int lttng_enable_channel(struct lttng_handle
*handle
,
563 struct lttng_channel
*chan
)
565 struct lttcomm_session_msg lsm
;
572 memcpy(&lsm
.u
.channel
.chan
, chan
, sizeof(lsm
.u
.channel
.chan
));
575 lsm
.cmd_type
= LTTNG_ENABLE_CHANNEL
;
577 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
579 copy_string(lsm
.session
.name
, handle
->session_name
,
580 sizeof(lsm
.session
.name
));
582 return ask_sessiond(&lsm
, NULL
);
586 * All tracing will be stopped for registered events of the channel.
588 int lttng_disable_channel(struct lttng_handle
*handle
, const char *name
)
590 struct lttcomm_session_msg lsm
;
597 copy_string(lsm
.u
.disable
.channel_name
, name
,
598 sizeof(lsm
.u
.disable
.channel_name
));
601 lsm
.cmd_type
= LTTNG_DISABLE_CHANNEL
;
603 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
605 copy_string(lsm
.session
.name
, handle
->session_name
,
606 sizeof(lsm
.session
.name
));
608 return ask_sessiond(&lsm
, NULL
);
612 * List all available tracepoints of domain.
614 * Return the size (bytes) of the list and set the events array.
615 * On error, return negative value.
617 int lttng_list_tracepoints(struct lttng_handle
*handle
,
618 struct lttng_event
**events
)
621 struct lttcomm_session_msg lsm
;
627 lsm
.cmd_type
= LTTNG_LIST_TRACEPOINTS
;
628 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
630 ret
= ask_sessiond(&lsm
, (void **) events
);
635 return ret
/ sizeof(struct lttng_event
);
639 * Return a human readable string of code
641 const char *lttng_strerror(int code
)
643 if (code
> -LTTCOMM_OK
) {
644 return "Ended with errors";
647 return lttcomm_get_readable_code(code
);
651 * Create a brand new session using name.
653 int lttng_create_session(const char *name
, const char *path
)
655 struct lttcomm_session_msg lsm
;
657 lsm
.cmd_type
= LTTNG_CREATE_SESSION
;
658 copy_string(lsm
.session
.name
, name
, sizeof(lsm
.session
.name
));
659 copy_string(lsm
.session
.path
, path
, sizeof(lsm
.session
.path
));
661 return ask_sessiond(&lsm
, NULL
);
665 * Destroy session using name.
667 int lttng_destroy_session(struct lttng_handle
*handle
)
669 struct lttcomm_session_msg lsm
;
675 lsm
.cmd_type
= LTTNG_DESTROY_SESSION
;
676 copy_string(lsm
.session
.name
, handle
->session_name
,
677 sizeof(lsm
.session
.name
));
679 return ask_sessiond(&lsm
, NULL
);
683 * Ask the session daemon for all available sessions.
685 * Return number of session.
686 * On error, return negative value.
688 int lttng_list_sessions(struct lttng_session
**sessions
)
691 struct lttcomm_session_msg lsm
;
693 lsm
.cmd_type
= LTTNG_LIST_SESSIONS
;
694 ret
= ask_sessiond(&lsm
, (void**) sessions
);
699 return ret
/ sizeof(struct lttng_session
);
703 * List domain of a session.
705 int lttng_list_domains(struct lttng_handle
*handle
,
706 struct lttng_domain
**domains
)
709 struct lttcomm_session_msg lsm
;
715 lsm
.cmd_type
= LTTNG_LIST_DOMAINS
;
717 copy_string(lsm
.session
.name
, handle
->session_name
,
718 sizeof(lsm
.session
.name
));
720 ret
= ask_sessiond(&lsm
, (void**) domains
);
725 return ret
/ sizeof(struct lttng_domain
);
729 * List channels of a session
731 int lttng_list_channels(struct lttng_handle
*handle
,
732 struct lttng_channel
**channels
)
735 struct lttcomm_session_msg lsm
;
741 lsm
.cmd_type
= LTTNG_LIST_CHANNELS
;
742 copy_string(lsm
.session
.name
, handle
->session_name
,
743 sizeof(lsm
.session
.name
));
745 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
747 ret
= ask_sessiond(&lsm
, (void**) channels
);
752 return ret
/ sizeof(struct lttng_channel
);
756 * List events of a session channel.
758 int lttng_list_events(struct lttng_handle
*handle
,
759 const char *channel_name
, struct lttng_event
**events
)
762 struct lttcomm_session_msg lsm
;
768 lsm
.cmd_type
= LTTNG_LIST_EVENTS
;
769 copy_string(lsm
.session
.name
, handle
->session_name
,
770 sizeof(lsm
.session
.name
));
771 copy_string(lsm
.u
.list
.channel_name
, channel_name
,
772 sizeof(lsm
.u
.list
.channel_name
));
774 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
776 ret
= ask_sessiond(&lsm
, (void**) events
);
781 return ret
/ sizeof(struct lttng_event
);
785 * lttng_set_tracing_group
787 * Set tracing group variable with name. This function
788 * allocate memory pointed by tracing_group.
790 int lttng_set_tracing_group(const char *name
)
792 if (asprintf(&tracing_group
, "%s", name
) < 0) {
802 int lttng_calibrate(struct lttng_handle
*handle
,
803 struct lttng_calibrate
*calibrate
)
805 struct lttcomm_session_msg lsm
;
811 lsm
.cmd_type
= LTTNG_CALIBRATE
;
812 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
814 memcpy(&lsm
.u
.calibrate
, calibrate
, sizeof(lsm
.u
.calibrate
));
816 return ask_sessiond(&lsm
, NULL
);
820 * Check if session daemon is alive.
822 * Return 1 if alive or 0 if not.
825 int lttng_session_daemon_alive(void)
829 ret
= set_session_daemon_path();
835 if (strlen(sessiond_sock_path
) == 0) {
836 /* No socket path set. Weird error */
840 ret
= try_connect_sessiond(sessiond_sock_path
);
853 static void __attribute__((constructor
)) init()
855 /* Set default session group */
856 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP
);