4 * Holds LTTng per-session event registry.
6 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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
25 #include <urcu/list.h>
26 #include <urcu/hlist.h>
35 #include <lttng/ust-endian.h>
39 #include <urcu/compiler.h>
40 #include <urcu/uatomic.h>
41 #include <urcu/arch.h>
43 #include <lttng/tracepoint.h>
44 #include <lttng/ust-events.h>
46 #include <usterr-signal-safe.h>
52 #include "lttng-ust-uuid.h"
54 #include "tracepoint-internal.h"
55 #include "lttng-tracer.h"
56 #include "lttng-tracer-core.h"
58 #include "../libringbuffer/shm.h"
62 * The sessions mutex is the centralized mutex across UST tracing
63 * control and probe registration. All operations within this file are
64 * called by the communication thread, under ust_lock protection.
66 static pthread_mutex_t sessions_mutex
= PTHREAD_MUTEX_INITIALIZER
;
70 pthread_mutex_lock(&sessions_mutex
);
75 pthread_mutex_unlock(&sessions_mutex
);
78 static CDS_LIST_HEAD(sessions
);
80 static void _lttng_event_destroy(struct lttng_event
*event
);
83 void lttng_session_lazy_sync_enablers(struct lttng_session
*session
);
85 void lttng_session_sync_enablers(struct lttng_session
*session
);
87 void lttng_enabler_destroy(struct lttng_enabler
*enabler
);
90 * Called with ust lock held.
92 int lttng_session_active(void)
94 struct lttng_session
*iter
;
96 cds_list_for_each_entry(iter
, &sessions
, node
) {
104 int lttng_loglevel_match(int loglevel
,
105 unsigned int has_loglevel
,
106 enum lttng_ust_loglevel_type req_type
,
109 if (req_type
== LTTNG_UST_LOGLEVEL_ALL
)
112 loglevel
= TRACE_DEFAULT
;
114 case LTTNG_UST_LOGLEVEL_RANGE
:
115 if (loglevel
<= req_loglevel
|| req_loglevel
== -1)
119 case LTTNG_UST_LOGLEVEL_SINGLE
:
120 if (loglevel
== req_loglevel
|| req_loglevel
== -1)
124 case LTTNG_UST_LOGLEVEL_ALL
:
130 void synchronize_trace(void)
135 struct lttng_session
*lttng_session_create(void)
137 struct lttng_session
*session
;
140 session
= zmalloc(sizeof(struct lttng_session
));
143 CDS_INIT_LIST_HEAD(&session
->chan_head
);
144 CDS_INIT_LIST_HEAD(&session
->events_head
);
145 CDS_INIT_LIST_HEAD(&session
->enablers_head
);
146 for (i
= 0; i
< LTTNG_UST_EVENT_HT_SIZE
; i
++)
147 CDS_INIT_HLIST_HEAD(&session
->events_ht
.table
[i
]);
148 cds_list_add(&session
->node
, &sessions
);
153 * Only used internally at session destruction.
156 void _lttng_channel_unmap(struct lttng_channel
*lttng_chan
)
158 struct channel
*chan
;
159 struct lttng_ust_shm_handle
*handle
;
161 cds_list_del(<tng_chan
->node
);
162 lttng_destroy_context(lttng_chan
->ctx
);
163 chan
= lttng_chan
->chan
;
164 handle
= lttng_chan
->handle
;
166 * note: lttng_chan is private data contained within handle. It
167 * will be freed along with the handle.
169 channel_destroy(chan
, handle
, 0);
173 void register_event(struct lttng_event
*event
)
176 const struct lttng_event_desc
*desc
;
178 assert(event
->registered
== 0);
180 ret
= __tracepoint_probe_register(desc
->name
,
181 desc
->probe_callback
,
182 event
, desc
->signature
);
185 event
->registered
= 1;
189 void unregister_event(struct lttng_event
*event
)
192 const struct lttng_event_desc
*desc
;
194 assert(event
->registered
== 1);
196 ret
= __tracepoint_probe_unregister(desc
->name
,
197 desc
->probe_callback
,
201 event
->registered
= 0;
205 * Only used internally at session destruction.
208 void _lttng_event_unregister(struct lttng_event
*event
)
210 if (event
->registered
)
211 unregister_event(event
);
214 void lttng_session_destroy(struct lttng_session
*session
)
216 struct lttng_channel
*chan
, *tmpchan
;
217 struct lttng_event
*event
, *tmpevent
;
218 struct lttng_enabler
*enabler
, *tmpenabler
;
220 CMM_ACCESS_ONCE(session
->active
) = 0;
221 cds_list_for_each_entry(event
, &session
->events_head
, node
) {
222 _lttng_event_unregister(event
);
224 synchronize_trace(); /* Wait for in-flight events to complete */
225 cds_list_for_each_entry_safe(enabler
, tmpenabler
,
226 &session
->enablers_head
, node
)
227 lttng_enabler_destroy(enabler
);
228 cds_list_for_each_entry_safe(event
, tmpevent
,
229 &session
->events_head
, node
)
230 _lttng_event_destroy(event
);
231 cds_list_for_each_entry_safe(chan
, tmpchan
, &session
->chan_head
, node
)
232 _lttng_channel_unmap(chan
);
233 cds_list_del(&session
->node
);
237 int lttng_session_enable(struct lttng_session
*session
)
240 struct lttng_channel
*chan
;
243 if (session
->active
) {
248 notify_socket
= lttng_get_notify_socket(session
->owner
);
249 if (notify_socket
< 0)
250 return notify_socket
;
252 /* Set transient enabler state to "enabled" */
254 /* We need to sync enablers with session before activation. */
255 lttng_session_sync_enablers(session
);
258 * Snapshot the number of events per channel to know the type of header
261 cds_list_for_each_entry(chan
, &session
->chan_head
, node
) {
262 const struct lttng_ctx
*ctx
;
263 const struct lttng_event_field
*fields
= NULL
;
264 size_t nr_fields
= 0;
267 /* don't change it if session stop/restart */
268 if (chan
->header_type
)
272 nr_fields
= ctx
->nr_fields
;
273 fields
= &ctx
->fields
->event_field
;
275 ret
= ustcomm_register_channel(notify_socket
,
283 DBG("Error (%d) registering channel to sessiond", ret
);
286 if (chan_id
!= chan
->id
) {
287 DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
293 /* Set atomically the state to "active" */
294 CMM_ACCESS_ONCE(session
->active
) = 1;
295 CMM_ACCESS_ONCE(session
->been_active
) = 1;
300 int lttng_session_disable(struct lttng_session
*session
)
304 if (!session
->active
) {
308 /* Set atomically the state to "inactive" */
309 CMM_ACCESS_ONCE(session
->active
) = 0;
311 /* Set transient enabler state to "disabled" */
313 lttng_session_sync_enablers(session
);
318 int lttng_channel_enable(struct lttng_channel
*channel
)
322 if (channel
->enabled
) {
326 /* Set transient enabler state to "enabled" */
328 lttng_session_sync_enablers(channel
->session
);
329 /* Set atomically the state to "enabled" */
330 CMM_ACCESS_ONCE(channel
->enabled
) = 1;
335 int lttng_channel_disable(struct lttng_channel
*channel
)
339 if (!channel
->enabled
) {
343 /* Set atomically the state to "disabled" */
344 CMM_ACCESS_ONCE(channel
->enabled
) = 0;
345 /* Set transient enabler state to "enabled" */
347 lttng_session_sync_enablers(channel
->session
);
353 * Supports event creation while tracing session is active.
356 int lttng_event_create(const struct lttng_event_desc
*desc
,
357 struct lttng_channel
*chan
)
359 const char *event_name
= desc
->name
;
360 struct lttng_event
*event
;
361 struct lttng_session
*session
= chan
->session
;
362 struct cds_hlist_head
*head
;
363 struct cds_hlist_node
*node
;
365 size_t name_len
= strlen(event_name
);
367 int notify_socket
, loglevel
;
370 hash
= jhash(event_name
, name_len
, 0);
371 head
= &chan
->session
->events_ht
.table
[hash
& (LTTNG_UST_EVENT_HT_SIZE
- 1)];
372 cds_hlist_for_each_entry(event
, node
, head
, hlist
) {
374 if (!strncmp(event
->desc
->name
, desc
->name
,
375 LTTNG_UST_SYM_NAME_LEN
- 1)
376 && chan
== event
->chan
) {
382 notify_socket
= lttng_get_notify_socket(session
->owner
);
383 if (notify_socket
< 0) {
389 * Check if loglevel match. Refuse to connect event if not.
391 event
= zmalloc(sizeof(struct lttng_event
));
398 /* Event will be enabled by enabler sync. */
400 event
->registered
= 0;
401 CDS_INIT_LIST_HEAD(&event
->bytecode_runtime_head
);
402 CDS_INIT_LIST_HEAD(&event
->enablers_ref_head
);
406 loglevel
= *(*event
->desc
->loglevel
);
408 loglevel
= TRACE_DEFAULT
;
409 if (desc
->u
.ext
.model_emf_uri
)
410 uri
= *(desc
->u
.ext
.model_emf_uri
);
414 /* Fetch event ID from sessiond */
415 ret
= ustcomm_register_event(notify_socket
,
426 DBG("Error (%d) registering event to sessiond", ret
);
427 goto sessiond_register_error
;
430 /* Populate lttng_event structure before tracepoint registration. */
432 cds_list_add(&event
->node
, &chan
->session
->events_head
);
433 cds_hlist_add_head(&event
->hlist
, head
);
436 sessiond_register_error
:
445 int lttng_desc_match_wildcard_enabler(const struct lttng_event_desc
*desc
,
446 struct lttng_enabler
*enabler
)
449 unsigned int has_loglevel
= 0;
451 assert(enabler
->type
== LTTNG_ENABLER_WILDCARD
);
452 /* Compare excluding final '*' */
453 if (strncmp(desc
->name
, enabler
->event_param
.name
,
454 strlen(enabler
->event_param
.name
) - 1))
456 if (desc
->loglevel
) {
457 loglevel
= *(*desc
->loglevel
);
460 if (!lttng_loglevel_match(loglevel
,
462 enabler
->event_param
.loglevel_type
,
463 enabler
->event_param
.loglevel
))
469 int lttng_desc_match_event_enabler(const struct lttng_event_desc
*desc
,
470 struct lttng_enabler
*enabler
)
473 unsigned int has_loglevel
= 0;
475 assert(enabler
->type
== LTTNG_ENABLER_EVENT
);
476 if (strcmp(desc
->name
, enabler
->event_param
.name
))
478 if (desc
->loglevel
) {
479 loglevel
= *(*desc
->loglevel
);
482 if (!lttng_loglevel_match(loglevel
,
484 enabler
->event_param
.loglevel_type
,
485 enabler
->event_param
.loglevel
))
491 int lttng_desc_match_enabler(const struct lttng_event_desc
*desc
,
492 struct lttng_enabler
*enabler
)
494 switch (enabler
->type
) {
495 case LTTNG_ENABLER_WILDCARD
:
496 return lttng_desc_match_wildcard_enabler(desc
, enabler
);
497 case LTTNG_ENABLER_EVENT
:
498 return lttng_desc_match_event_enabler(desc
, enabler
);
505 int lttng_event_match_enabler(struct lttng_event
*event
,
506 struct lttng_enabler
*enabler
)
508 if (lttng_desc_match_enabler(event
->desc
, enabler
)
509 && event
->chan
== enabler
->chan
)
516 struct lttng_enabler_ref
* lttng_event_enabler_ref(struct lttng_event
*event
,
517 struct lttng_enabler
*enabler
)
519 struct lttng_enabler_ref
*enabler_ref
;
521 cds_list_for_each_entry(enabler_ref
,
522 &event
->enablers_ref_head
, node
) {
523 if (enabler_ref
->ref
== enabler
)
530 * Create struct lttng_event if it is missing and present in the list of
534 void lttng_create_event_if_missing(struct lttng_enabler
*enabler
)
536 struct lttng_session
*session
= enabler
->chan
->session
;
537 struct lttng_probe_desc
*probe_desc
;
538 const struct lttng_event_desc
*desc
;
539 struct lttng_event
*event
;
541 struct cds_list_head
*probe_list
;
543 probe_list
= lttng_get_probe_list_head();
545 * For each probe event, if we find that a probe event matches
546 * our enabler, create an associated lttng_event if not
549 cds_list_for_each_entry(probe_desc
, probe_list
, head
) {
550 for (i
= 0; i
< probe_desc
->nr_events
; i
++) {
552 struct cds_hlist_head
*head
;
553 struct cds_hlist_node
*node
;
554 const char *event_name
;
558 desc
= probe_desc
->event_desc
[i
];
559 if (!lttng_desc_match_enabler(desc
, enabler
))
561 event_name
= desc
->name
;
562 name_len
= strlen(event_name
);
565 * Check if already created.
567 hash
= jhash(event_name
, name_len
, 0);
568 head
= &session
->events_ht
.table
[hash
& (LTTNG_UST_EVENT_HT_SIZE
- 1)];
569 cds_hlist_for_each_entry(event
, node
, head
, hlist
) {
570 if (event
->desc
== desc
571 && event
->chan
== enabler
->chan
)
578 * We need to create an event for this
581 ret
= lttng_event_create(probe_desc
->event_desc
[i
],
584 DBG("Unable to create event %s, error %d\n",
585 probe_desc
->event_desc
[i
]->name
, ret
);
592 * Create events associated with an enabler (if not already present),
593 * and add backward reference from the event to the enabler.
596 int lttng_enabler_ref_events(struct lttng_enabler
*enabler
)
598 struct lttng_session
*session
= enabler
->chan
->session
;
599 struct lttng_event
*event
;
601 /* First ensure that probe events are created for this enabler. */
602 lttng_create_event_if_missing(enabler
);
604 /* For each event matching enabler in session event list. */
605 cds_list_for_each_entry(event
, &session
->events_head
, node
) {
606 struct lttng_enabler_ref
*enabler_ref
;
608 if (!lttng_event_match_enabler(event
, enabler
))
611 enabler_ref
= lttng_event_enabler_ref(event
, enabler
);
614 * If no backward ref, create it.
615 * Add backward ref from event to enabler.
617 enabler_ref
= zmalloc(sizeof(*enabler_ref
));
620 enabler_ref
->ref
= enabler
;
621 cds_list_add(&enabler_ref
->node
,
622 &event
->enablers_ref_head
);
626 * Link filter bytecodes if not linked yet.
628 lttng_enabler_event_link_bytecode(event
, enabler
);
630 /* TODO: merge event context. */
636 * Called at library load: connect the probe on all enablers matching
638 * called with session mutex held.
639 * TODO: currently, for each desc added, we iterate on all event desc
640 * (inefficient). We should create specific code that only target the
643 int lttng_fix_pending_event_desc(const struct lttng_event_desc
*desc
)
645 struct lttng_session
*session
;
647 cds_list_for_each_entry(session
, &sessions
, node
) {
648 lttng_session_lazy_sync_enablers(session
);
654 * Only used internally at session destruction.
657 void _lttng_event_destroy(struct lttng_event
*event
)
659 struct lttng_enabler_ref
*enabler_ref
, *tmp_enabler_ref
;
661 cds_list_del(&event
->node
);
662 lttng_destroy_context(event
->ctx
);
663 lttng_free_event_filter_runtime(event
);
664 /* Free event enabler refs */
665 cds_list_for_each_entry_safe(enabler_ref
, tmp_enabler_ref
,
666 &event
->enablers_ref_head
, node
)
671 void lttng_ust_events_exit(void)
673 struct lttng_session
*session
, *tmpsession
;
675 cds_list_for_each_entry_safe(session
, tmpsession
, &sessions
, node
)
676 lttng_session_destroy(session
);
680 * Enabler management.
682 struct lttng_enabler
*lttng_enabler_create(enum lttng_enabler_type type
,
683 struct lttng_ust_event
*event_param
,
684 struct lttng_channel
*chan
)
686 struct lttng_enabler
*enabler
;
688 enabler
= zmalloc(sizeof(*enabler
));
691 enabler
->type
= type
;
692 CDS_INIT_LIST_HEAD(&enabler
->filter_bytecode_head
);
693 memcpy(&enabler
->event_param
, event_param
,
694 sizeof(enabler
->event_param
));
695 enabler
->chan
= chan
;
697 enabler
->enabled
= 1;
698 cds_list_add(&enabler
->node
, &enabler
->chan
->session
->enablers_head
);
699 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
703 int lttng_enabler_enable(struct lttng_enabler
*enabler
)
705 enabler
->enabled
= 1;
706 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
710 int lttng_enabler_disable(struct lttng_enabler
*enabler
)
712 enabler
->enabled
= 0;
713 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
717 int lttng_enabler_attach_bytecode(struct lttng_enabler
*enabler
,
718 struct lttng_ust_filter_bytecode_node
*bytecode
)
720 bytecode
->enabler
= enabler
;
721 cds_list_add_tail(&bytecode
->node
, &enabler
->filter_bytecode_head
);
722 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
726 int lttng_attach_context(struct lttng_ust_context
*context_param
,
727 struct lttng_ctx
**ctx
, struct lttng_session
*session
)
730 * We cannot attach a context after trace has been started for a
731 * session because the metadata does not allow expressing this
732 * information outside of the original channel scope.
734 if (session
->been_active
)
737 switch (context_param
->ctx
) {
738 case LTTNG_UST_CONTEXT_PTHREAD_ID
:
739 return lttng_add_pthread_id_to_ctx(ctx
);
740 case LTTNG_UST_CONTEXT_VTID
:
741 return lttng_add_vtid_to_ctx(ctx
);
742 case LTTNG_UST_CONTEXT_VPID
:
743 return lttng_add_vpid_to_ctx(ctx
);
744 case LTTNG_UST_CONTEXT_PROCNAME
:
745 return lttng_add_procname_to_ctx(ctx
);
751 int lttng_enabler_attach_context(struct lttng_enabler
*enabler
,
752 struct lttng_ust_context
*context_param
)
754 #if 0 // disabled for now.
755 struct lttng_session
*session
= enabler
->chan
->session
;
758 ret
= lttng_attach_context(context_param
, &enabler
->ctx
,
762 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
768 void lttng_enabler_destroy(struct lttng_enabler
*enabler
)
770 struct lttng_ust_filter_bytecode_node
*filter_node
, *tmp_filter_node
;
772 /* Destroy filter bytecode */
773 cds_list_for_each_entry_safe(filter_node
, tmp_filter_node
,
774 &enabler
->filter_bytecode_head
, node
) {
778 /* Destroy contexts */
779 lttng_destroy_context(enabler
->ctx
);
781 cds_list_del(&enabler
->node
);
786 * lttng_session_sync_enablers should be called just before starting a
790 void lttng_session_sync_enablers(struct lttng_session
*session
)
792 struct lttng_enabler
*enabler
;
793 struct lttng_event
*event
;
795 cds_list_for_each_entry(enabler
, &session
->enablers_head
, node
)
796 lttng_enabler_ref_events(enabler
);
798 * For each event, if at least one of its enablers is enabled,
799 * and its channel and session transient states are enabled, we
800 * enable the event, else we disable it.
802 cds_list_for_each_entry(event
, &session
->events_head
, node
) {
803 struct lttng_enabler_ref
*enabler_ref
;
804 struct lttng_bytecode_runtime
*runtime
;
805 int enabled
= 0, has_enablers_without_bytecode
= 0;
808 cds_list_for_each_entry(enabler_ref
,
809 &event
->enablers_ref_head
, node
) {
810 if (enabler_ref
->ref
->enabled
) {
816 * Enabled state is based on union of enablers, with
817 * intesection of session and channel transient enable
820 enabled
= enabled
&& session
->tstate
&& event
->chan
->tstate
;
822 CMM_STORE_SHARED(event
->enabled
, enabled
);
824 * Sync tracepoint registration with event enabled
828 if (!event
->registered
)
829 register_event(event
);
831 if (event
->registered
)
832 unregister_event(event
);
835 /* Check if has enablers without bytecode enabled */
836 cds_list_for_each_entry(enabler_ref
,
837 &event
->enablers_ref_head
, node
) {
838 if (enabler_ref
->ref
->enabled
839 && cds_list_empty(&enabler_ref
->ref
->filter_bytecode_head
)) {
840 has_enablers_without_bytecode
= 1;
844 event
->has_enablers_without_bytecode
=
845 has_enablers_without_bytecode
;
848 cds_list_for_each_entry(runtime
,
849 &event
->bytecode_runtime_head
, node
) {
850 lttng_filter_sync_state(runtime
);
856 * Apply enablers to session events, adding events to session if need
857 * be. It is required after each modification applied to an active
858 * session, and right before session "start".
859 * "lazy" sync means we only sync if required.
862 void lttng_session_lazy_sync_enablers(struct lttng_session
*session
)
864 /* We can skip if session is not active */
865 if (!session
->active
)
867 lttng_session_sync_enablers(session
);