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_creds_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 */
345 data
= (void*) malloc(size
);
347 /* Get payload data */
348 ret
= recv_data_sessiond(data
, size
);
355 * Extra protection not to dereference a NULL pointer. If buf is NULL at
356 * this point, an error is returned and data is freed.
368 disconnect_sessiond();
373 * Create lttng handle and return pointer.
375 struct lttng_handle
*lttng_create_handle(const char *session_name
,
376 struct lttng_domain
*domain
)
378 struct lttng_handle
*handle
;
380 handle
= malloc(sizeof(struct lttng_handle
));
381 if (handle
== NULL
) {
382 perror("malloc handle");
386 /* Copy session name */
387 copy_string(handle
->session_name
, session_name
,
388 sizeof(handle
->session_name
));
390 /* Copy lttng domain */
391 copy_lttng_domain(&handle
->domain
, domain
);
398 * Destroy handle by free(3) the pointer.
400 void lttng_destroy_handle(struct lttng_handle
*handle
)
408 * Register an outside consumer.
410 int lttng_register_consumer(struct lttng_handle
*handle
,
411 const char *socket_path
)
413 struct lttcomm_session_msg lsm
;
415 lsm
.cmd_type
= LTTNG_REGISTER_CONSUMER
;
416 copy_string(lsm
.session
.name
, handle
->session_name
,
417 sizeof(lsm
.session
.name
));
418 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
420 copy_string(lsm
.u
.reg
.path
, socket_path
, sizeof(lsm
.u
.reg
.path
));
422 return ask_sessiond(&lsm
, NULL
);
426 * Start tracing for all trace of the session.
428 int lttng_start_tracing(const char *session_name
)
430 struct lttcomm_session_msg lsm
;
432 if (session_name
== NULL
) {
436 lsm
.cmd_type
= LTTNG_START_TRACE
;
438 copy_string(lsm
.session
.name
, session_name
, sizeof(lsm
.session
.name
));
440 return ask_sessiond(&lsm
, NULL
);
444 * Stop tracing for all trace of the session.
446 int lttng_stop_tracing(const char *session_name
)
448 struct lttcomm_session_msg lsm
;
450 if (session_name
== NULL
) {
454 lsm
.cmd_type
= LTTNG_STOP_TRACE
;
456 copy_string(lsm
.session
.name
, session_name
, sizeof(lsm
.session
.name
));
458 return ask_sessiond(&lsm
, NULL
);
462 * Add context to event or/and channel.
464 int lttng_add_context(struct lttng_handle
*handle
,
465 struct lttng_event_context
*ctx
, const char *event_name
,
466 const char *channel_name
)
468 struct lttcomm_session_msg lsm
;
470 /* Safety check. Both are mandatory */
471 if (handle
== NULL
|| ctx
== NULL
) {
475 lsm
.cmd_type
= LTTNG_ADD_CONTEXT
;
477 /* Copy channel name */
478 copy_string(lsm
.u
.context
.channel_name
, channel_name
,
479 sizeof(lsm
.u
.context
.channel_name
));
480 /* Copy event name */
481 copy_string(lsm
.u
.context
.event_name
, event_name
,
482 sizeof(lsm
.u
.context
.event_name
));
484 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
486 memcpy(&lsm
.u
.context
.ctx
, ctx
, sizeof(struct lttng_event_context
));
488 copy_string(lsm
.session
.name
, handle
->session_name
,
489 sizeof(lsm
.session
.name
));
491 return ask_sessiond(&lsm
, NULL
);
497 int lttng_enable_event(struct lttng_handle
*handle
,
498 struct lttng_event
*ev
, const char *channel_name
)
500 struct lttcomm_session_msg lsm
;
502 if (handle
== NULL
|| ev
== NULL
) {
506 /* If no channel name, we put the default name */
507 if (channel_name
== NULL
) {
508 copy_string(lsm
.u
.enable
.channel_name
, DEFAULT_CHANNEL_NAME
,
509 sizeof(lsm
.u
.enable
.channel_name
));
511 copy_string(lsm
.u
.enable
.channel_name
, channel_name
,
512 sizeof(lsm
.u
.enable
.channel_name
));
515 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
517 if (ev
->name
[0] != '\0') {
518 lsm
.cmd_type
= LTTNG_ENABLE_EVENT
;
520 lsm
.cmd_type
= LTTNG_ENABLE_ALL_EVENT
;
522 memcpy(&lsm
.u
.enable
.event
, ev
, sizeof(lsm
.u
.enable
.event
));
524 copy_string(lsm
.session
.name
, handle
->session_name
,
525 sizeof(lsm
.session
.name
));
527 return ask_sessiond(&lsm
, NULL
);
531 * Disable event of a channel and domain.
533 int lttng_disable_event(struct lttng_handle
*handle
, const char *name
,
534 const char *channel_name
)
536 struct lttcomm_session_msg lsm
;
538 if (handle
== NULL
) {
543 copy_string(lsm
.u
.disable
.channel_name
, channel_name
,
544 sizeof(lsm
.u
.disable
.channel_name
));
546 copy_string(lsm
.u
.disable
.channel_name
, DEFAULT_CHANNEL_NAME
,
547 sizeof(lsm
.u
.disable
.channel_name
));
550 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
553 copy_string(lsm
.u
.disable
.name
, name
, sizeof(lsm
.u
.disable
.name
));
554 lsm
.cmd_type
= LTTNG_DISABLE_EVENT
;
556 lsm
.cmd_type
= LTTNG_DISABLE_ALL_EVENT
;
559 copy_string(lsm
.session
.name
, handle
->session_name
,
560 sizeof(lsm
.session
.name
));
562 return ask_sessiond(&lsm
, NULL
);
566 * Enable channel per domain
568 int lttng_enable_channel(struct lttng_handle
*handle
,
569 struct lttng_channel
*chan
)
571 struct lttcomm_session_msg lsm
;
574 * NULL arguments are forbidden. No default values.
576 if (handle
== NULL
|| chan
== NULL
) {
580 memcpy(&lsm
.u
.channel
.chan
, chan
, sizeof(lsm
.u
.channel
.chan
));
582 lsm
.cmd_type
= LTTNG_ENABLE_CHANNEL
;
584 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
586 copy_string(lsm
.session
.name
, handle
->session_name
,
587 sizeof(lsm
.session
.name
));
589 return ask_sessiond(&lsm
, NULL
);
593 * All tracing will be stopped for registered events of the channel.
595 int lttng_disable_channel(struct lttng_handle
*handle
, const char *name
)
597 struct lttcomm_session_msg lsm
;
599 /* Safety check. Both are mandatory */
600 if (handle
== NULL
|| name
== NULL
) {
604 lsm
.cmd_type
= LTTNG_DISABLE_CHANNEL
;
606 copy_string(lsm
.u
.disable
.channel_name
, name
,
607 sizeof(lsm
.u
.disable
.channel_name
));
609 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
611 copy_string(lsm
.session
.name
, handle
->session_name
,
612 sizeof(lsm
.session
.name
));
614 return ask_sessiond(&lsm
, NULL
);
618 * List all available tracepoints of domain.
620 * Return the size (bytes) of the list and set the events array.
621 * On error, return negative value.
623 int lttng_list_tracepoints(struct lttng_handle
*handle
,
624 struct lttng_event
**events
)
627 struct lttcomm_session_msg lsm
;
629 if (handle
== NULL
) {
633 lsm
.cmd_type
= LTTNG_LIST_TRACEPOINTS
;
634 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
636 ret
= ask_sessiond(&lsm
, (void **) events
);
641 return ret
/ sizeof(struct lttng_event
);
645 * Return a human readable string of code
647 const char *lttng_strerror(int code
)
649 if (code
> -LTTCOMM_OK
) {
650 return "Ended with errors";
653 return lttcomm_get_readable_code(code
);
657 * Create a brand new session using name.
659 int lttng_create_session(const char *name
, const char *path
)
661 struct lttcomm_session_msg lsm
;
663 lsm
.cmd_type
= LTTNG_CREATE_SESSION
;
664 copy_string(lsm
.session
.name
, name
, sizeof(lsm
.session
.name
));
665 copy_string(lsm
.session
.path
, path
, sizeof(lsm
.session
.path
));
667 return ask_sessiond(&lsm
, NULL
);
671 * Destroy session using name.
673 int lttng_destroy_session(const char *session_name
)
675 struct lttcomm_session_msg lsm
;
677 if (session_name
== NULL
) {
681 lsm
.cmd_type
= LTTNG_DESTROY_SESSION
;
683 copy_string(lsm
.session
.name
, session_name
, sizeof(lsm
.session
.name
));
685 return ask_sessiond(&lsm
, NULL
);
689 * Ask the session daemon for all available sessions.
691 * Return number of session.
692 * On error, return negative value.
694 int lttng_list_sessions(struct lttng_session
**sessions
)
697 struct lttcomm_session_msg lsm
;
699 lsm
.cmd_type
= LTTNG_LIST_SESSIONS
;
700 ret
= ask_sessiond(&lsm
, (void**) sessions
);
705 return ret
/ sizeof(struct lttng_session
);
709 * List domain of a session.
711 int lttng_list_domains(const char *session_name
,
712 struct lttng_domain
**domains
)
715 struct lttcomm_session_msg lsm
;
717 if (session_name
== NULL
) {
721 lsm
.cmd_type
= LTTNG_LIST_DOMAINS
;
723 copy_string(lsm
.session
.name
, session_name
, sizeof(lsm
.session
.name
));
725 ret
= ask_sessiond(&lsm
, (void**) domains
);
730 return ret
/ sizeof(struct lttng_domain
);
734 * List channels of a session
736 int lttng_list_channels(struct lttng_handle
*handle
,
737 struct lttng_channel
**channels
)
740 struct lttcomm_session_msg lsm
;
742 if (handle
== NULL
) {
746 lsm
.cmd_type
= LTTNG_LIST_CHANNELS
;
747 copy_string(lsm
.session
.name
, handle
->session_name
,
748 sizeof(lsm
.session
.name
));
750 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
752 ret
= ask_sessiond(&lsm
, (void**) channels
);
757 return ret
/ sizeof(struct lttng_channel
);
761 * List events of a session channel.
763 int lttng_list_events(struct lttng_handle
*handle
,
764 const char *channel_name
, struct lttng_event
**events
)
767 struct lttcomm_session_msg lsm
;
769 /* Safety check. An handle and channel name are mandatory */
770 if (handle
== NULL
|| channel_name
== NULL
) {
774 lsm
.cmd_type
= LTTNG_LIST_EVENTS
;
775 copy_string(lsm
.session
.name
, handle
->session_name
,
776 sizeof(lsm
.session
.name
));
777 copy_string(lsm
.u
.list
.channel_name
, channel_name
,
778 sizeof(lsm
.u
.list
.channel_name
));
780 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
782 ret
= ask_sessiond(&lsm
, (void**) events
);
787 return ret
/ sizeof(struct lttng_event
);
791 * Set tracing group variable with name. This function allocate memory pointed
794 int lttng_set_tracing_group(const char *name
)
800 if (asprintf(&tracing_group
, "%s", name
) < 0) {
810 int lttng_calibrate(struct lttng_handle
*handle
,
811 struct lttng_calibrate
*calibrate
)
813 struct lttcomm_session_msg lsm
;
815 /* Safety check. NULL pointer are forbidden */
816 if (handle
== NULL
|| calibrate
== NULL
) {
820 lsm
.cmd_type
= LTTNG_CALIBRATE
;
821 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
823 memcpy(&lsm
.u
.calibrate
, calibrate
, sizeof(lsm
.u
.calibrate
));
825 return ask_sessiond(&lsm
, NULL
);
829 * Set default channel attributes.
831 void lttng_channel_set_default_attr(struct lttng_domain
*domain
,
832 struct lttng_channel_attr
*attr
)
835 if (attr
== NULL
|| domain
== NULL
) {
839 switch (domain
->type
) {
840 case LTTNG_DOMAIN_KERNEL
:
841 attr
->overwrite
= DEFAULT_CHANNEL_OVERWRITE
;
842 attr
->switch_timer_interval
= DEFAULT_CHANNEL_SWITCH_TIMER
;
843 attr
->read_timer_interval
= DEFAULT_CHANNEL_READ_TIMER
;
845 attr
->subbuf_size
= DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE
;
846 attr
->num_subbuf
= DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM
;
847 attr
->output
= DEFAULT_KERNEL_CHANNEL_OUTPUT
;
849 case LTTNG_DOMAIN_UST
:
850 case LTTNG_DOMAIN_UST_EXEC_NAME
:
851 case LTTNG_DOMAIN_UST_PID
:
852 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN
:
853 attr
->overwrite
= DEFAULT_CHANNEL_OVERWRITE
;
854 attr
->switch_timer_interval
= DEFAULT_CHANNEL_SWITCH_TIMER
;
855 attr
->read_timer_interval
= DEFAULT_CHANNEL_READ_TIMER
;
857 attr
->subbuf_size
= DEFAULT_UST_CHANNEL_SUBBUF_SIZE
;
858 attr
->num_subbuf
= DEFAULT_UST_CHANNEL_SUBBUF_NUM
;
859 attr
->output
= DEFAULT_UST_CHANNEL_OUTPUT
;
862 /* Default behavior */
863 memset(attr
, 0, sizeof(struct lttng_channel_attr
));
869 * Check if session daemon is alive.
871 * Return 1 if alive or 0 if not.
874 int lttng_session_daemon_alive(void)
878 ret
= set_session_daemon_path();
884 if (strlen(sessiond_sock_path
) == 0) {
885 /* No socket path set. Weird error */
889 ret
= try_connect_sessiond(sessiond_sock_path
);
902 static void __attribute__((constructor
)) init()
904 /* Set default session group */
905 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP
);