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
;
341 data
= (void*) malloc(size
);
343 /* Get payload data */
344 ret
= recv_data_sessiond(data
, size
);
351 * Extra protection not to dereference a NULL pointer. If buf is NULL at
352 * this point, an error is returned and data is freed.
364 disconnect_sessiond();
369 * Create lttng handle and return pointer.
371 struct lttng_handle
*lttng_create_handle(const char *session_name
,
372 struct lttng_domain
*domain
)
374 struct lttng_handle
*handle
;
376 handle
= malloc(sizeof(struct lttng_handle
));
377 if (handle
== NULL
) {
378 perror("malloc handle");
382 /* Copy session name */
383 copy_string(handle
->session_name
, session_name
,
384 sizeof(handle
->session_name
));
386 /* Copy lttng domain */
387 copy_lttng_domain(&handle
->domain
, domain
);
394 * Destroy handle by free(3) the pointer.
396 void lttng_destroy_handle(struct lttng_handle
*handle
)
404 * Register an outside consumer.
406 int lttng_register_consumer(struct lttng_handle
*handle
,
407 const char *socket_path
)
409 struct lttcomm_session_msg lsm
;
411 lsm
.cmd_type
= LTTNG_REGISTER_CONSUMER
;
412 copy_string(lsm
.session
.name
, handle
->session_name
,
413 sizeof(lsm
.session
.name
));
414 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
416 copy_string(lsm
.u
.reg
.path
, socket_path
, sizeof(lsm
.u
.reg
.path
));
418 return ask_sessiond(&lsm
, NULL
);
422 * Start tracing for all trace of the session.
424 int lttng_start_tracing(struct lttng_handle
*handle
)
426 struct lttcomm_session_msg lsm
;
432 lsm
.cmd_type
= LTTNG_START_TRACE
;
433 copy_string(lsm
.session
.name
, handle
->session_name
,
434 sizeof(lsm
.session
.name
));
436 return ask_sessiond(&lsm
, NULL
);
440 * Stop tracing for all trace of the session.
442 int lttng_stop_tracing(struct lttng_handle
*handle
)
444 struct lttcomm_session_msg lsm
;
446 lsm
.cmd_type
= LTTNG_STOP_TRACE
;
447 copy_string(lsm
.session
.name
, handle
->session_name
,
448 sizeof(lsm
.session
.name
));
450 return ask_sessiond(&lsm
, NULL
);
454 * Add context to event or/and channel.
456 int lttng_add_context(struct lttng_handle
*handle
,
457 struct lttng_event_context
*ctx
, const char *event_name
,
458 const char *channel_name
)
460 struct lttcomm_session_msg lsm
;
466 lsm
.cmd_type
= LTTNG_ADD_CONTEXT
;
468 /* Copy channel name */
469 copy_string(lsm
.u
.context
.channel_name
, channel_name
,
470 sizeof(lsm
.u
.context
.channel_name
));
471 /* Copy event name */
472 copy_string(lsm
.u
.context
.event_name
, event_name
,
473 sizeof(lsm
.u
.context
.event_name
));
475 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
478 memcpy(&lsm
.u
.context
.ctx
, ctx
, sizeof(struct lttng_event_context
));
481 copy_string(lsm
.session
.name
, handle
->session_name
,
482 sizeof(lsm
.session
.name
));
484 return ask_sessiond(&lsm
, NULL
);
490 int lttng_enable_event(struct lttng_handle
*handle
,
491 struct lttng_event
*ev
, const char *channel_name
)
493 struct lttcomm_session_msg lsm
;
495 if (!handle
|| ev
== NULL
) {
499 if (channel_name
== NULL
) {
500 copy_string(lsm
.u
.enable
.channel_name
, DEFAULT_CHANNEL_NAME
,
501 sizeof(lsm
.u
.enable
.channel_name
));
503 copy_string(lsm
.u
.enable
.channel_name
, channel_name
,
504 sizeof(lsm
.u
.enable
.channel_name
));
507 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
509 if (ev
->name
[0] != '\0') {
510 lsm
.cmd_type
= LTTNG_ENABLE_EVENT
;
512 lsm
.cmd_type
= LTTNG_ENABLE_ALL_EVENT
;
514 memcpy(&lsm
.u
.enable
.event
, ev
, sizeof(lsm
.u
.enable
.event
));
516 copy_string(lsm
.session
.name
, handle
->session_name
,
517 sizeof(lsm
.session
.name
));
519 return ask_sessiond(&lsm
, NULL
);
523 * Disable event of a channel and domain.
525 int lttng_disable_event(struct lttng_handle
*handle
, const char *name
,
526 const char *channel_name
)
528 struct lttcomm_session_msg lsm
;
535 copy_string(lsm
.u
.disable
.channel_name
, channel_name
,
536 sizeof(lsm
.u
.disable
.channel_name
));
538 copy_string(lsm
.u
.disable
.channel_name
, DEFAULT_CHANNEL_NAME
,
539 sizeof(lsm
.u
.disable
.channel_name
));
542 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
545 copy_string(lsm
.u
.disable
.name
, name
, sizeof(lsm
.u
.disable
.name
));
546 lsm
.cmd_type
= LTTNG_DISABLE_EVENT
;
548 lsm
.cmd_type
= LTTNG_DISABLE_ALL_EVENT
;
551 copy_string(lsm
.session
.name
, handle
->session_name
,
552 sizeof(lsm
.session
.name
));
554 return ask_sessiond(&lsm
, NULL
);
558 * Enable channel per domain
560 int lttng_enable_channel(struct lttng_handle
*handle
,
561 struct lttng_channel
*chan
)
563 struct lttcomm_session_msg lsm
;
570 memcpy(&lsm
.u
.channel
.chan
, chan
, sizeof(lsm
.u
.channel
.chan
));
573 lsm
.cmd_type
= LTTNG_ENABLE_CHANNEL
;
575 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
577 copy_string(lsm
.session
.name
, handle
->session_name
,
578 sizeof(lsm
.session
.name
));
580 return ask_sessiond(&lsm
, NULL
);
584 * All tracing will be stopped for registered events of the channel.
586 int lttng_disable_channel(struct lttng_handle
*handle
, const char *name
)
588 struct lttcomm_session_msg lsm
;
595 copy_string(lsm
.u
.disable
.channel_name
, name
,
596 sizeof(lsm
.u
.disable
.channel_name
));
599 lsm
.cmd_type
= LTTNG_DISABLE_CHANNEL
;
601 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
603 copy_string(lsm
.session
.name
, handle
->session_name
,
604 sizeof(lsm
.session
.name
));
606 return ask_sessiond(&lsm
, NULL
);
610 * List all available tracepoints of domain.
612 * Return the size (bytes) of the list and set the events array.
613 * On error, return negative value.
615 int lttng_list_tracepoints(struct lttng_handle
*handle
,
616 struct lttng_event
**events
)
619 struct lttcomm_session_msg lsm
;
625 lsm
.cmd_type
= LTTNG_LIST_TRACEPOINTS
;
626 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
628 ret
= ask_sessiond(&lsm
, (void **) events
);
633 return ret
/ sizeof(struct lttng_event
);
637 * Return a human readable string of code
639 const char *lttng_get_readable_code(int code
)
641 if (code
> -LTTCOMM_OK
) {
642 return "Ended with errors";
645 return lttcomm_get_readable_code(code
);
649 * Create a brand new session using name.
651 int lttng_create_session(const char *name
, const char *path
)
653 struct lttcomm_session_msg lsm
;
655 lsm
.cmd_type
= LTTNG_CREATE_SESSION
;
656 copy_string(lsm
.session
.name
, name
, sizeof(lsm
.session
.name
));
657 copy_string(lsm
.session
.path
, path
, sizeof(lsm
.session
.path
));
659 return ask_sessiond(&lsm
, NULL
);
663 * Destroy session using name.
665 int lttng_destroy_session(struct lttng_handle
*handle
)
667 struct lttcomm_session_msg lsm
;
673 lsm
.cmd_type
= LTTNG_DESTROY_SESSION
;
674 copy_string(lsm
.session
.name
, handle
->session_name
,
675 sizeof(lsm
.session
.name
));
677 return ask_sessiond(&lsm
, NULL
);
681 * Ask the session daemon for all available sessions.
683 * Return number of session.
684 * On error, return negative value.
686 int lttng_list_sessions(struct lttng_session
**sessions
)
689 struct lttcomm_session_msg lsm
;
691 lsm
.cmd_type
= LTTNG_LIST_SESSIONS
;
692 ret
= ask_sessiond(&lsm
, (void**) sessions
);
697 return ret
/ sizeof(struct lttng_session
);
701 * List domain of a session.
703 int lttng_list_domains(struct lttng_handle
*handle
,
704 struct lttng_domain
**domains
)
707 struct lttcomm_session_msg lsm
;
713 lsm
.cmd_type
= LTTNG_LIST_DOMAINS
;
715 copy_string(lsm
.session
.name
, handle
->session_name
,
716 sizeof(lsm
.session
.name
));
718 ret
= ask_sessiond(&lsm
, (void**) domains
);
723 return ret
/ sizeof(struct lttng_domain
);
727 * List channels of a session
729 int lttng_list_channels(struct lttng_handle
*handle
,
730 struct lttng_channel
**channels
)
733 struct lttcomm_session_msg lsm
;
739 lsm
.cmd_type
= LTTNG_LIST_CHANNELS
;
740 copy_string(lsm
.session
.name
, handle
->session_name
,
741 sizeof(lsm
.session
.name
));
743 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
745 ret
= ask_sessiond(&lsm
, (void**) channels
);
750 return ret
/ sizeof(struct lttng_channel
);
754 * List events of a session channel.
756 int lttng_list_events(struct lttng_handle
*handle
,
757 const char *channel_name
, struct lttng_event
**events
)
760 struct lttcomm_session_msg lsm
;
766 lsm
.cmd_type
= LTTNG_LIST_EVENTS
;
767 copy_string(lsm
.session
.name
, handle
->session_name
,
768 sizeof(lsm
.session
.name
));
769 copy_string(lsm
.u
.list
.channel_name
, channel_name
,
770 sizeof(lsm
.u
.list
.channel_name
));
772 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
774 ret
= ask_sessiond(&lsm
, (void**) events
);
779 return ret
/ sizeof(struct lttng_event
);
783 * lttng_set_tracing_group
785 * Set tracing group variable with name. This function
786 * allocate memory pointed by tracing_group.
788 int lttng_set_tracing_group(const char *name
)
790 if (asprintf(&tracing_group
, "%s", name
) < 0) {
800 int lttng_calibrate(struct lttng_handle
*handle
,
801 struct lttng_calibrate
*calibrate
)
803 struct lttcomm_session_msg lsm
;
809 lsm
.cmd_type
= LTTNG_CALIBRATE
;
810 copy_lttng_domain(&lsm
.domain
, &handle
->domain
);
812 memcpy(&lsm
.u
.calibrate
, calibrate
, sizeof(lsm
.u
.calibrate
));
814 return ask_sessiond(&lsm
, NULL
);
818 * Check if session daemon is alive.
820 * Return 1 if alive or 0 if not.
823 int lttng_session_daemon_alive(void)
827 ret
= set_session_daemon_path();
833 if (strlen(sessiond_sock_path
) == 0) {
834 /* No socket path set. Weird error */
838 ret
= try_connect_sessiond(sessiond_sock_path
);
851 static void __attribute__((constructor
)) init()
853 /* Set default session group */
854 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP
);