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
);
81 static int _lttng_event_unregister(struct lttng_event
*event
);
84 void lttng_session_lazy_sync_enablers(struct lttng_session
*session
);
86 void lttng_session_sync_enablers(struct lttng_session
*session
);
88 void lttng_enabler_destroy(struct lttng_enabler
*enabler
);
91 * Called with ust lock held.
93 int lttng_session_active(void)
95 struct lttng_session
*iter
;
97 cds_list_for_each_entry(iter
, &sessions
, node
) {
105 int lttng_loglevel_match(int loglevel
,
106 unsigned int has_loglevel
,
107 enum lttng_ust_loglevel_type req_type
,
110 if (req_type
== LTTNG_UST_LOGLEVEL_ALL
)
113 loglevel
= TRACE_DEFAULT
;
115 case LTTNG_UST_LOGLEVEL_RANGE
:
116 if (loglevel
<= req_loglevel
|| req_loglevel
== -1)
120 case LTTNG_UST_LOGLEVEL_SINGLE
:
121 if (loglevel
== req_loglevel
|| req_loglevel
== -1)
125 case LTTNG_UST_LOGLEVEL_ALL
:
131 void synchronize_trace(void)
136 struct lttng_session
*lttng_session_create(void)
138 struct lttng_session
*session
;
141 session
= zmalloc(sizeof(struct lttng_session
));
144 CDS_INIT_LIST_HEAD(&session
->chan_head
);
145 CDS_INIT_LIST_HEAD(&session
->events_head
);
146 CDS_INIT_LIST_HEAD(&session
->enablers_head
);
147 for (i
= 0; i
< LTTNG_UST_EVENT_HT_SIZE
; i
++)
148 CDS_INIT_HLIST_HEAD(&session
->events_ht
.table
[i
]);
149 cds_list_add(&session
->node
, &sessions
);
154 * Only used internally at session destruction.
157 void _lttng_channel_unmap(struct lttng_channel
*lttng_chan
)
159 struct channel
*chan
;
160 struct lttng_ust_shm_handle
*handle
;
162 cds_list_del(<tng_chan
->node
);
163 lttng_destroy_context(lttng_chan
->ctx
);
164 chan
= lttng_chan
->chan
;
165 handle
= lttng_chan
->handle
;
167 * note: lttng_chan is private data contained within handle. It
168 * will be freed along with the handle.
170 channel_destroy(chan
, handle
, 0);
173 void lttng_session_destroy(struct lttng_session
*session
)
175 struct lttng_channel
*chan
, *tmpchan
;
176 struct lttng_event
*event
, *tmpevent
;
177 struct lttng_enabler
*enabler
, *tmpenabler
;
180 CMM_ACCESS_ONCE(session
->active
) = 0;
181 cds_list_for_each_entry(event
, &session
->events_head
, node
) {
182 ret
= _lttng_event_unregister(event
);
185 synchronize_trace(); /* Wait for in-flight events to complete */
186 cds_list_for_each_entry_safe(enabler
, tmpenabler
,
187 &session
->enablers_head
, node
)
188 lttng_enabler_destroy(enabler
);
189 cds_list_for_each_entry_safe(event
, tmpevent
,
190 &session
->events_head
, node
)
191 _lttng_event_destroy(event
);
192 cds_list_for_each_entry_safe(chan
, tmpchan
, &session
->chan_head
, node
)
193 _lttng_channel_unmap(chan
);
194 cds_list_del(&session
->node
);
198 int lttng_session_enable(struct lttng_session
*session
)
201 struct lttng_channel
*chan
;
204 if (session
->active
) {
209 notify_socket
= lttng_get_notify_socket(session
->owner
);
210 if (notify_socket
< 0)
211 return notify_socket
;
213 /* We need to sync enablers with session before activation. */
214 lttng_session_sync_enablers(session
);
217 * Snapshot the number of events per channel to know the type of header
220 cds_list_for_each_entry(chan
, &session
->chan_head
, node
) {
221 const struct lttng_ctx
*ctx
;
222 const struct lttng_event_field
*fields
= NULL
;
223 size_t nr_fields
= 0;
225 /* don't change it if session stop/restart */
226 if (chan
->header_type
)
230 nr_fields
= ctx
->nr_fields
;
231 fields
= &ctx
->fields
->event_field
;
233 ret
= ustcomm_register_channel(notify_socket
,
241 DBG("Error (%d) registering channel to sessiond", ret
);
246 CMM_ACCESS_ONCE(session
->active
) = 1;
247 CMM_ACCESS_ONCE(session
->been_active
) = 1;
252 int lttng_session_disable(struct lttng_session
*session
)
256 if (!session
->active
) {
260 CMM_ACCESS_ONCE(session
->active
) = 0;
265 int lttng_channel_enable(struct lttng_channel
*channel
)
269 old
= uatomic_xchg(&channel
->enabled
, 1);
275 int lttng_channel_disable(struct lttng_channel
*channel
)
279 old
= uatomic_xchg(&channel
->enabled
, 0);
286 * Supports event creation while tracing session is active.
289 int lttng_event_create(const struct lttng_event_desc
*desc
,
290 struct lttng_channel
*chan
)
292 const char *event_name
= desc
->name
;
293 struct lttng_event
*event
;
294 struct lttng_session
*session
= chan
->session
;
295 struct cds_hlist_head
*head
;
296 struct cds_hlist_node
*node
;
298 size_t name_len
= strlen(event_name
);
300 int notify_socket
, loglevel
;
303 hash
= jhash(event_name
, name_len
, 0);
304 head
= &chan
->session
->events_ht
.table
[hash
& (LTTNG_UST_EVENT_HT_SIZE
- 1)];
305 cds_hlist_for_each_entry(event
, node
, head
, hlist
) {
307 if (!strncmp(event
->desc
->name
,
309 LTTNG_UST_SYM_NAME_LEN
- 1)) {
315 notify_socket
= lttng_get_notify_socket(session
->owner
);
316 if (notify_socket
< 0) {
322 * Check if loglevel match. Refuse to connect event if not.
324 event
= zmalloc(sizeof(struct lttng_event
));
332 CDS_INIT_LIST_HEAD(&event
->bytecode_runtime_head
);
333 CDS_INIT_LIST_HEAD(&event
->enablers_ref_head
);
337 loglevel
= *(*event
->desc
->loglevel
);
339 loglevel
= TRACE_DEFAULT
;
340 if (desc
->u
.ext
.model_emf_uri
)
341 uri
= *(desc
->u
.ext
.model_emf_uri
);
345 /* Fetch event ID from sessiond */
346 ret
= ustcomm_register_event(notify_socket
,
357 DBG("Error (%d) registering event to sessiond", ret
);
358 goto sessiond_register_error
;
361 /* Populate lttng_event structure before tracepoint registration. */
363 ret
= __tracepoint_probe_register(event_name
,
364 desc
->probe_callback
,
365 event
, desc
->signature
);
367 goto tracepoint_register_error
;
369 cds_list_add(&event
->node
, &chan
->session
->events_head
);
370 cds_hlist_add_head(&event
->hlist
, head
);
373 tracepoint_register_error
:
374 sessiond_register_error
:
383 int lttng_desc_match_wildcard_enabler(const struct lttng_event_desc
*desc
,
384 struct lttng_enabler
*enabler
)
387 unsigned int has_loglevel
;
389 assert(enabler
->type
== LTTNG_ENABLER_WILDCARD
);
390 /* Compare excluding final '*' */
391 if (strncmp(desc
->name
, enabler
->event_param
.name
,
392 strlen(enabler
->event_param
.name
) - 1))
394 if (desc
->loglevel
) {
395 loglevel
= *(*desc
->loglevel
);
398 if (!lttng_loglevel_match(loglevel
,
400 enabler
->event_param
.loglevel_type
,
401 enabler
->event_param
.loglevel
))
407 int lttng_desc_match_event_enabler(const struct lttng_event_desc
*desc
,
408 struct lttng_enabler
*enabler
)
411 unsigned int has_loglevel
= 0;
413 assert(enabler
->type
== LTTNG_ENABLER_EVENT
);
414 if (strcmp(desc
->name
, enabler
->event_param
.name
))
416 if (desc
->loglevel
) {
417 loglevel
= *(*desc
->loglevel
);
420 if (!lttng_loglevel_match(loglevel
,
422 enabler
->event_param
.loglevel_type
,
423 enabler
->event_param
.loglevel
))
429 int lttng_desc_match_enabler(const struct lttng_event_desc
*desc
,
430 struct lttng_enabler
*enabler
)
432 switch (enabler
->type
) {
433 case LTTNG_ENABLER_WILDCARD
:
434 return lttng_desc_match_wildcard_enabler(desc
, enabler
);
435 case LTTNG_ENABLER_EVENT
:
436 return lttng_desc_match_event_enabler(desc
, enabler
);
443 int lttng_event_match_enabler(struct lttng_event
*event
,
444 struct lttng_enabler
*enabler
)
446 return lttng_desc_match_enabler(event
->desc
, enabler
);
450 struct lttng_enabler_ref
* lttng_event_enabler_ref(struct lttng_event
*event
,
451 struct lttng_enabler
*enabler
)
453 struct lttng_enabler_ref
*enabler_ref
;
455 cds_list_for_each_entry(enabler_ref
,
456 &event
->enablers_ref_head
, node
) {
457 if (enabler_ref
->ref
== enabler
)
464 * Create struct lttng_event if it is missing and present in the list of
468 void lttng_create_event_if_missing(struct lttng_enabler
*enabler
)
470 struct lttng_session
*session
= enabler
->chan
->session
;
471 struct lttng_probe_desc
*probe_desc
;
472 const struct lttng_event_desc
*desc
;
473 struct lttng_event
*event
;
475 struct cds_list_head
*probe_list
;
477 probe_list
= lttng_get_probe_list_head();
479 * For each probe event, if we find that a probe event matches
480 * our enabler, create an associated lttng_event if not
483 cds_list_for_each_entry(probe_desc
, probe_list
, head
) {
484 for (i
= 0; i
< probe_desc
->nr_events
; i
++) {
486 struct cds_hlist_head
*head
;
487 struct cds_hlist_node
*node
;
488 const char *event_name
;
492 desc
= probe_desc
->event_desc
[i
];
493 if (!lttng_desc_match_enabler(desc
, enabler
))
495 event_name
= desc
->name
;
496 name_len
= strlen(event_name
);
499 * Check if already created.
501 hash
= jhash(event_name
, name_len
, 0);
502 head
= &session
->events_ht
.table
[hash
& (LTTNG_UST_EVENT_HT_SIZE
- 1)];
503 cds_hlist_for_each_entry(event
, node
, head
, hlist
) {
504 if (event
->desc
== desc
)
511 * We need to create an event for this
514 ret
= lttng_event_create(probe_desc
->event_desc
[i
],
517 DBG("Unable to create event %s, error %d\n",
518 probe_desc
->event_desc
[i
]->name
, ret
);
525 * Create events associated with an enabler (if not already present),
526 * and add backward reference from the event to the enabler.
529 int lttng_enabler_ref_events(struct lttng_enabler
*enabler
)
531 struct lttng_session
*session
= enabler
->chan
->session
;
532 struct lttng_event
*event
;
534 /* First ensure that probe events are created for this enabler. */
535 lttng_create_event_if_missing(enabler
);
537 /* For each event matching enabler in session event list. */
538 cds_list_for_each_entry(event
, &session
->events_head
, node
) {
539 struct lttng_enabler_ref
*enabler_ref
;
541 if (!lttng_event_match_enabler(event
, enabler
))
544 enabler_ref
= lttng_event_enabler_ref(event
, enabler
);
547 * If no backward ref, create it.
548 * Add backward ref from event to enabler.
550 enabler_ref
= zmalloc(sizeof(*enabler_ref
));
553 enabler_ref
->ref
= enabler
;
554 cds_list_add(&enabler_ref
->node
,
555 &event
->enablers_ref_head
);
559 * Link filter bytecodes if not linked yet.
561 lttng_enabler_event_link_bytecode(event
, enabler
);
563 /* TODO: merge event context. */
569 * Called at library load: connect the probe on all enablers matching
571 * called with session mutex held.
572 * TODO: currently, for each desc added, we iterate on all event desc
573 * (inefficient). We should create specific code that only target the
576 int lttng_fix_pending_event_desc(const struct lttng_event_desc
*desc
)
578 struct lttng_session
*session
;
580 cds_list_for_each_entry(session
, &sessions
, node
) {
581 lttng_session_lazy_sync_enablers(session
);
587 * Only used internally at session destruction.
589 int _lttng_event_unregister(struct lttng_event
*event
)
591 return __tracepoint_probe_unregister(event
->desc
->name
,
592 event
->desc
->probe_callback
,
597 * Only used internally at session destruction.
600 void _lttng_event_destroy(struct lttng_event
*event
)
602 struct lttng_enabler_ref
*enabler_ref
, *tmp_enabler_ref
;
604 cds_list_del(&event
->node
);
605 lttng_destroy_context(event
->ctx
);
606 lttng_free_event_filter_runtime(event
);
607 /* Free event enabler refs */
608 cds_list_for_each_entry_safe(enabler_ref
, tmp_enabler_ref
,
609 &event
->enablers_ref_head
, node
)
614 void lttng_ust_events_exit(void)
616 struct lttng_session
*session
, *tmpsession
;
618 cds_list_for_each_entry_safe(session
, tmpsession
, &sessions
, node
)
619 lttng_session_destroy(session
);
623 * Enabler management.
625 struct lttng_enabler
*lttng_enabler_create(enum lttng_enabler_type type
,
626 struct lttng_ust_event
*event_param
,
627 struct lttng_channel
*chan
)
629 struct lttng_enabler
*enabler
;
631 enabler
= zmalloc(sizeof(*enabler
));
634 enabler
->type
= type
;
635 CDS_INIT_LIST_HEAD(&enabler
->filter_bytecode_head
);
636 memcpy(&enabler
->event_param
, event_param
,
637 sizeof(enabler
->event_param
));
638 enabler
->chan
= chan
;
640 enabler
->enabled
= 1;
641 cds_list_add(&enabler
->node
, &enabler
->chan
->session
->enablers_head
);
642 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
646 int lttng_enabler_enable(struct lttng_enabler
*enabler
)
648 enabler
->enabled
= 1;
649 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
653 int lttng_enabler_disable(struct lttng_enabler
*enabler
)
655 enabler
->enabled
= 0;
656 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
660 int lttng_enabler_attach_bytecode(struct lttng_enabler
*enabler
,
661 struct lttng_ust_filter_bytecode_node
*bytecode
)
663 bytecode
->enabler
= enabler
;
664 cds_list_add_tail(&bytecode
->node
, &enabler
->filter_bytecode_head
);
665 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
669 int lttng_attach_context(struct lttng_ust_context
*context_param
,
670 struct lttng_ctx
**ctx
, struct lttng_session
*session
)
673 * We cannot attach a context after trace has been started for a
674 * session because the metadata does not allow expressing this
675 * information outside of the original channel scope.
677 if (session
->been_active
)
680 switch (context_param
->ctx
) {
681 case LTTNG_UST_CONTEXT_PTHREAD_ID
:
682 return lttng_add_pthread_id_to_ctx(ctx
);
683 case LTTNG_UST_CONTEXT_VTID
:
684 return lttng_add_vtid_to_ctx(ctx
);
685 case LTTNG_UST_CONTEXT_VPID
:
686 return lttng_add_vpid_to_ctx(ctx
);
687 case LTTNG_UST_CONTEXT_PROCNAME
:
688 return lttng_add_procname_to_ctx(ctx
);
694 int lttng_enabler_attach_context(struct lttng_enabler
*enabler
,
695 struct lttng_ust_context
*context_param
)
697 #if 0 // disabled for now.
698 struct lttng_session
*session
= enabler
->chan
->session
;
701 ret
= lttng_attach_context(context_param
, &enabler
->ctx
,
705 lttng_session_lazy_sync_enablers(enabler
->chan
->session
);
711 void lttng_enabler_destroy(struct lttng_enabler
*enabler
)
713 struct lttng_ust_filter_bytecode_node
*filter_node
, *tmp_filter_node
;
715 /* Destroy filter bytecode */
716 cds_list_for_each_entry_safe(filter_node
, tmp_filter_node
,
717 &enabler
->filter_bytecode_head
, node
) {
721 /* Destroy contexts */
722 lttng_destroy_context(enabler
->ctx
);
724 cds_list_del(&enabler
->node
);
729 * lttng_session_sync_enablers should be called just before starting a
733 void lttng_session_sync_enablers(struct lttng_session
*session
)
735 struct lttng_enabler
*enabler
;
736 struct lttng_event
*event
;
738 cds_list_for_each_entry(enabler
, &session
->enablers_head
, node
)
739 lttng_enabler_ref_events(enabler
);
741 * For each event, if at least one of its enablers is enabled,
742 * we enable the event, else we disable it.
744 cds_list_for_each_entry(event
, &session
->events_head
, node
) {
745 struct lttng_enabler_ref
*enabler_ref
;
746 struct lttng_bytecode_runtime
*runtime
;
747 int enabled
= 0, has_enablers_without_bytecode
= 0;
750 cds_list_for_each_entry(enabler_ref
,
751 &event
->enablers_ref_head
, node
) {
752 if (enabler_ref
->ref
->enabled
) {
757 event
->enabled
= enabled
;
759 /* Check if has enablers without bytecode enabled */
760 cds_list_for_each_entry(enabler_ref
,
761 &event
->enablers_ref_head
, node
) {
762 if (enabler_ref
->ref
->enabled
763 && cds_list_empty(&enabler_ref
->ref
->filter_bytecode_head
)) {
764 has_enablers_without_bytecode
= 1;
768 event
->has_enablers_without_bytecode
=
769 has_enablers_without_bytecode
;
772 cds_list_for_each_entry(runtime
,
773 &event
->bytecode_runtime_head
, node
) {
774 lttng_filter_sync_state(runtime
);
780 * Apply enablers to session events, adding events to session if need
781 * be. It is required after each modification applied to an active
782 * session, and right before session "start".
783 * "lazy" sync means we only sync if required.
786 void lttng_session_lazy_sync_enablers(struct lttng_session
*session
)
788 /* We can skip if session is not active */
789 if (!session
->active
)
791 lttng_session_sync_enablers(session
);