4 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * Holds LTTng per-session event registry.
8 * Dual LGPL v2.1/GPL v2 license.
13 #include <urcu/list.h>
16 #include <urcu/compiler.h>
17 #include <urcu/uatomic.h>
18 #include <uuid/uuid.h>
19 #include <ust/tracepoint.h>
21 #include "usterr_signal_safe.h"
23 #include "ltt-events.h"
24 #include "ltt-tracer.h"
27 static CDS_LIST_HEAD(sessions
);
28 static CDS_LIST_HEAD(ltt_transport_list
);
29 static DEFINE_MUTEX(sessions_mutex
);
31 static void _ltt_event_destroy(struct ltt_event
*event
);
32 static void _ltt_channel_destroy(struct ltt_channel
*chan
);
33 static int _ltt_event_unregister(struct ltt_event
*event
);
35 int _ltt_event_metadata_statedump(struct ltt_session
*session
,
36 struct ltt_channel
*chan
,
37 struct ltt_event
*event
);
39 int _ltt_session_metadata_statedump(struct ltt_session
*session
);
41 void synchronize_trace(void)
46 struct ltt_session
*ltt_session_create(void)
48 struct ltt_session
*session
;
50 pthread_mutex_lock(&sessions_mutex
);
51 session
= zmalloc(sizeof(struct ltt_session
));
54 CDS_INIT_LIST_HEAD(&session
->chan
);
55 CDS_INIT_LIST_HEAD(&session
->events
);
56 uuid_generate(session
->uuid
);
57 cds_list_add(&session
->list
, &sessions
);
58 pthread_mutex_unlock(&sessions_mutex
);
62 void ltt_session_destroy(struct ltt_session
*session
)
64 struct ltt_channel
*chan
, *tmpchan
;
65 struct ltt_event
*event
, *tmpevent
;
68 pthread_mutex_lock(&sessions_mutex
);
69 CMM_ACCESS_ONCE(session
->active
) = 0;
70 cds_list_for_each_entry(event
, &session
->events
, list
) {
71 ret
= _ltt_event_unregister(event
);
74 synchronize_trace(); /* Wait for in-flight events to complete */
75 cds_list_for_each_entry_safe(event
, tmpevent
, &session
->events
, list
)
76 _ltt_event_destroy(event
);
77 cds_list_for_each_entry_safe(chan
, tmpchan
, &session
->chan
, list
)
78 _ltt_channel_destroy(chan
);
79 cds_list_del(&session
->list
);
80 pthread_mutex_unlock(&sessions_mutex
);
84 int ltt_session_enable(struct ltt_session
*session
)
87 struct ltt_channel
*chan
;
89 pthread_mutex_lock(&sessions_mutex
);
90 if (session
->active
) {
96 * Snapshot the number of events per channel to know the type of header
99 cds_list_for_each_entry(chan
, &session
->chan
, list
) {
100 if (chan
->header_type
)
101 continue; /* don't change it if session stop/restart */
102 if (chan
->free_event_id
< 31)
103 chan
->header_type
= 1; /* compact */
105 chan
->header_type
= 2; /* large */
108 CMM_ACCESS_ONCE(session
->active
) = 1;
109 CMM_ACCESS_ONCE(session
->been_active
) = 1;
110 ret
= _ltt_session_metadata_statedump(session
);
112 CMM_ACCESS_ONCE(session
->active
) = 0;
114 pthread_mutex_unlock(&sessions_mutex
);
118 int ltt_session_disable(struct ltt_session
*session
)
122 pthread_mutex_lock(&sessions_mutex
);
123 if (!session
->active
) {
127 CMM_ACCESS_ONCE(session
->active
) = 0;
129 pthread_mutex_unlock(&sessions_mutex
);
133 int ltt_channel_enable(struct ltt_channel
*channel
)
137 if (channel
== channel
->session
->metadata
)
139 old
= uatomic_xchg(&channel
->enabled
, 1);
145 int ltt_channel_disable(struct ltt_channel
*channel
)
149 if (channel
== channel
->session
->metadata
)
151 old
= uatomic_xchg(&channel
->enabled
, 0);
157 int ltt_event_enable(struct ltt_event
*event
)
161 if (event
->chan
== event
->chan
->session
->metadata
)
163 old
= uatomic_xchg(&event
->enabled
, 1);
169 int ltt_event_disable(struct ltt_event
*event
)
173 if (event
->chan
== event
->chan
->session
->metadata
)
175 old
= uatomic_xchg(&event
->enabled
, 0);
181 static struct ltt_transport
*ltt_transport_find(const char *name
)
183 struct ltt_transport
*transport
;
185 cds_list_for_each_entry(transport
, <t_transport_list
, node
) {
186 if (!strcmp(transport
->name
, name
))
192 struct ltt_channel
*ltt_channel_create(struct ltt_session
*session
,
193 const char *transport_name
,
195 size_t subbuf_size
, size_t num_subbuf
,
196 unsigned int switch_timer_interval
,
197 unsigned int read_timer_interval
,
200 struct ltt_channel
*chan
;
201 struct ltt_transport
*transport
;
203 pthread_mutex_lock(&sessions_mutex
);
204 if (session
->been_active
)
205 goto active
; /* Refuse to add channel to active session */
206 transport
= ltt_transport_find(transport_name
);
208 DBG("LTTng transport %s not found\n",
212 chan
= zmalloc(sizeof(struct ltt_channel
));
215 chan
->session
= session
;
216 chan
->id
= session
->free_chan_id
++;
218 * Note: the channel creation op already writes into the packet
219 * headers. Therefore the "chan" information used as input
220 * should be already accessible.
222 chan
->chan
= transport
->ops
.channel_create("[lttng]", chan
, buf_addr
,
223 subbuf_size
, num_subbuf
, switch_timer_interval
,
224 read_timer_interval
, shmid
);
228 chan
->ops
= &transport
->ops
;
229 cds_list_add(&chan
->list
, &session
->chan
);
230 pthread_mutex_unlock(&sessions_mutex
);
238 pthread_mutex_unlock(&sessions_mutex
);
243 * Only used internally at session destruction.
246 void _ltt_channel_destroy(struct ltt_channel
*chan
)
248 chan
->ops
->channel_destroy(chan
->chan
);
249 cds_list_del(&chan
->list
);
250 lttng_destroy_context(chan
->ctx
);
255 * Supports event creation while tracing session is active.
257 struct ltt_event
*ltt_event_create(struct ltt_channel
*chan
,
258 struct lttng_ust_event
*event_param
,
261 struct ltt_event
*event
;
264 pthread_mutex_lock(&sessions_mutex
);
265 if (chan
->free_event_id
== -1UL)
268 * This is O(n^2) (for each event, the loop is called at event
269 * creation). Might require a hash if we have lots of events.
271 cds_list_for_each_entry(event
, &chan
->session
->events
, list
)
272 if (!strcmp(event
->desc
->name
, event_param
->name
))
274 event
= zmalloc(sizeof(struct ltt_event
));
278 event
->filter
= filter
;
279 event
->id
= chan
->free_event_id
++;
281 event
->instrumentation
= event_param
->instrumentation
;
282 /* Populate ltt_event structure before tracepoint registration. */
284 switch (event_param
->instrumentation
) {
285 case LTTNG_UST_TRACEPOINT
:
286 event
->desc
= ltt_event_get(event_param
->name
);
289 ret
= __tracepoint_probe_register(event_param
->name
,
290 event
->desc
->probe_callback
,
298 ret
= _ltt_event_metadata_statedump(chan
->session
, chan
, event
);
300 goto statedump_error
;
301 cds_list_add(&event
->list
, &chan
->session
->events
);
302 pthread_mutex_unlock(&sessions_mutex
);
306 WARN_ON_ONCE(__tracepoint_probe_unregister(event_param
->name
,
307 event
->desc
->probe_callback
,
309 ltt_event_put(event
->desc
);
315 pthread_mutex_unlock(&sessions_mutex
);
320 * Only used internally at session destruction.
322 int _ltt_event_unregister(struct ltt_event
*event
)
326 switch (event
->instrumentation
) {
327 case LTTNG_UST_TRACEPOINT
:
328 ret
= __tracepoint_probe_unregister(event
->desc
->name
,
329 event
->desc
->probe_callback
,
341 * Only used internally at session destruction.
344 void _ltt_event_destroy(struct ltt_event
*event
)
346 switch (event
->instrumentation
) {
347 case LTTNG_UST_TRACEPOINT
:
348 ltt_event_put(event
->desc
);
353 cds_list_del(&event
->list
);
354 lttng_destroy_context(event
->ctx
);
359 * We have exclusive access to our metadata buffer (protected by the
360 * sessions_mutex), so we can do racy operations such as looking for
361 * remaining space left in packet and write, since mutual exclusion
362 * protects us from concurrent writes.
364 int lttng_metadata_printf(struct ltt_session
*session
,
365 const char *fmt
, ...)
367 struct lib_ring_buffer_ctx ctx
;
368 struct ltt_channel
*chan
= session
->metadata
;
370 int ret
= 0, waitret
;
371 size_t len
, reserve_len
, pos
;
374 WARN_ON_ONCE(!CMM_ACCESS_ONCE(session
->active
));
377 ret
= vasprintf(&str
, fmt
, ap
);
385 for (pos
= 0; pos
< len
; pos
+= reserve_len
) {
386 reserve_len
= min_t(size_t,
387 chan
->ops
->packet_avail_size(chan
->chan
),
389 lib_ring_buffer_ctx_init(&ctx
, chan
->chan
, NULL
, reserve_len
,
392 * We don't care about metadata buffer's records lost
393 * count, because we always retry here. Report error if
394 * we need to bail out after timeout or being
397 waitret
= wait_cond_interruptible_timeout(
399 ret
= chan
->ops
->event_reserve(&ctx
, 0);
400 ret
!= -ENOBUFS
|| !ret
;
402 LTTNG_METADATA_TIMEOUT_MSEC
);
403 if (!waitret
|| waitret
== -EINTR
|| ret
) {
404 DBG("LTTng: Failure to write metadata to buffers (%s)\n",
405 waitret
== -EINTR
? "interrupted" :
406 (ret
== -ENOBUFS
? "timeout" : "I/O error"));
407 if (waitret
== -EINTR
)
411 chan
->ops
->event_write(&ctx
, &str
[pos
], reserve_len
);
412 chan
->ops
->event_commit(&ctx
);
420 int _ltt_field_statedump(struct ltt_session
*session
,
421 const struct lttng_event_field
*field
)
425 switch (field
->type
.atype
) {
427 ret
= lttng_metadata_printf(session
,
428 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } %s;\n",
429 field
->type
.u
.basic
.integer
.size
,
430 field
->type
.u
.basic
.integer
.alignment
,
431 field
->type
.u
.basic
.integer
.signedness
,
432 (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_none
)
434 : (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
437 field
->type
.u
.basic
.integer
.base
,
439 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
441 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
446 ret
= lttng_metadata_printf(session
,
448 field
->type
.u
.basic
.enumeration
.name
,
453 const struct lttng_basic_type
*elem_type
;
455 elem_type
= &field
->type
.u
.array
.elem_type
;
456 ret
= lttng_metadata_printf(session
,
457 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } %s[%u];\n",
458 elem_type
->u
.basic
.integer
.size
,
459 elem_type
->u
.basic
.integer
.alignment
,
460 elem_type
->u
.basic
.integer
.signedness
,
461 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
463 : (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
466 elem_type
->u
.basic
.integer
.base
,
468 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
470 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
472 field
->name
, field
->type
.u
.array
.length
);
477 const struct lttng_basic_type
*elem_type
;
478 const struct lttng_basic_type
*length_type
;
480 elem_type
= &field
->type
.u
.sequence
.elem_type
;
481 length_type
= &field
->type
.u
.sequence
.length_type
;
482 ret
= lttng_metadata_printf(session
,
483 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
484 length_type
->u
.basic
.integer
.size
,
485 (unsigned int) length_type
->u
.basic
.integer
.alignment
,
486 length_type
->u
.basic
.integer
.signedness
,
487 (length_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
489 : ((length_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
492 length_type
->u
.basic
.integer
.base
,
494 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
496 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
502 ret
= lttng_metadata_printf(session
,
503 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } %s[ __%s_length ];\n",
504 elem_type
->u
.basic
.integer
.size
,
505 (unsigned int) elem_type
->u
.basic
.integer
.alignment
,
506 elem_type
->u
.basic
.integer
.signedness
,
507 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
509 : ((elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
512 elem_type
->u
.basic
.integer
.base
,
514 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
516 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
524 /* Default encoding is UTF8 */
525 ret
= lttng_metadata_printf(session
,
527 field
->type
.u
.basic
.string
.encoding
== lttng_encode_ASCII
?
528 " { encoding = ASCII; }" : "",
539 int _ltt_context_metadata_statedump(struct ltt_session
*session
,
540 struct lttng_ctx
*ctx
)
547 for (i
= 0; i
< ctx
->nr_fields
; i
++) {
548 const struct lttng_ctx_field
*field
= &ctx
->fields
[i
];
550 ret
= _ltt_field_statedump(session
, &field
->event_field
);
558 int _ltt_fields_metadata_statedump(struct ltt_session
*session
,
559 struct ltt_event
*event
)
561 const struct lttng_event_desc
*desc
= event
->desc
;
565 for (i
= 0; i
< desc
->nr_fields
; i
++) {
566 const struct lttng_event_field
*field
= &desc
->fields
[i
];
568 ret
= _ltt_field_statedump(session
, field
);
576 int _ltt_event_metadata_statedump(struct ltt_session
*session
,
577 struct ltt_channel
*chan
,
578 struct ltt_event
*event
)
582 if (event
->metadata_dumped
|| !CMM_ACCESS_ONCE(session
->active
))
584 if (chan
== session
->metadata
)
587 ret
= lttng_metadata_printf(session
,
591 " stream_id = %u;\n",
599 ret
= lttng_metadata_printf(session
,
600 " context := struct {\n");
604 ret
= _ltt_context_metadata_statedump(session
, event
->ctx
);
608 ret
= lttng_metadata_printf(session
,
614 ret
= lttng_metadata_printf(session
,
615 " fields := struct {\n"
620 ret
= _ltt_fields_metadata_statedump(session
, event
);
625 * LTTng space reservation can only reserve multiples of the
628 ret
= lttng_metadata_printf(session
,
634 event
->metadata_dumped
= 1;
641 int _ltt_channel_metadata_statedump(struct ltt_session
*session
,
642 struct ltt_channel
*chan
)
646 if (chan
->metadata_dumped
|| !CMM_ACCESS_ONCE(session
->active
))
648 if (chan
== session
->metadata
)
651 WARN_ON_ONCE(!chan
->header_type
);
652 ret
= lttng_metadata_printf(session
,
655 " event.header := %s;\n"
656 " packet.context := struct packet_context;\n",
658 chan
->header_type
== 1 ? "struct event_header_compact" :
659 "struct event_header_large");
664 ret
= lttng_metadata_printf(session
,
665 " event.context := struct {\n");
669 ret
= _ltt_context_metadata_statedump(session
, chan
->ctx
);
673 ret
= lttng_metadata_printf(session
,
679 ret
= lttng_metadata_printf(session
,
682 chan
->metadata_dumped
= 1;
688 int _ltt_stream_packet_context_declare(struct ltt_session
*session
)
690 return lttng_metadata_printf(session
,
691 "struct packet_context {\n"
692 " uint64_t timestamp_begin;\n"
693 " uint64_t timestamp_end;\n"
694 " uint32_t events_discarded;\n"
695 " uint32_t content_size;\n"
696 " uint32_t packet_size;\n"
697 " uint32_t cpu_id;\n"
705 * id 31 is reserved to indicate an extended header.
708 * id: range: 0 - 65534.
709 * id 65535 is reserved to indicate an extended header.
712 int _ltt_event_header_declare(struct ltt_session
*session
)
714 return lttng_metadata_printf(session
,
715 "struct event_header_compact {\n"
716 " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
719 " uint27_t timestamp;\n"
723 " uint64_t timestamp;\n"
728 "struct event_header_large {\n"
729 " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
732 " uint32_t timestamp;\n"
736 " uint64_t timestamp;\n"
740 ltt_alignof(uint32_t) * CHAR_BIT
,
741 ltt_alignof(uint16_t) * CHAR_BIT
746 * Output metadata into this session's metadata buffers.
749 int _ltt_session_metadata_statedump(struct ltt_session
*session
)
751 unsigned char *uuid_c
= session
->uuid
;
753 struct ltt_channel
*chan
;
754 struct ltt_event
*event
;
757 if (!CMM_ACCESS_ONCE(session
->active
))
759 if (session
->metadata_dumped
)
761 if (!session
->metadata
) {
762 DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
766 snprintf(uuid_s
, sizeof(uuid_s
),
767 "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
768 uuid_c
[0], uuid_c
[1], uuid_c
[2], uuid_c
[3],
769 uuid_c
[4], uuid_c
[5], uuid_c
[6], uuid_c
[7],
770 uuid_c
[8], uuid_c
[9], uuid_c
[10], uuid_c
[11],
771 uuid_c
[12], uuid_c
[13], uuid_c
[14], uuid_c
[15]);
773 ret
= lttng_metadata_printf(session
,
774 "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
775 "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
776 "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
777 "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
778 "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
779 "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
785 " byte_order = %s;\n"
786 " packet.header := struct {\n"
788 " uint8_t uuid[16];\n"
789 " uint32_t stream_id;\n"
792 ltt_alignof(uint8_t) * CHAR_BIT
,
793 ltt_alignof(uint16_t) * CHAR_BIT
,
794 ltt_alignof(uint32_t) * CHAR_BIT
,
795 ltt_alignof(uint64_t) * CHAR_BIT
,
808 ret
= _ltt_stream_packet_context_declare(session
);
812 ret
= _ltt_event_header_declare(session
);
817 cds_list_for_each_entry(chan
, &session
->chan
, list
) {
818 ret
= _ltt_channel_metadata_statedump(session
, chan
);
823 cds_list_for_each_entry(event
, &session
->events
, list
) {
824 ret
= _ltt_event_metadata_statedump(session
, event
->chan
, event
);
828 session
->metadata_dumped
= 1;
834 * ltt_transport_register - LTT transport registration
835 * @transport: transport structure
837 * Registers a transport which can be used as output to extract the data out of
840 void ltt_transport_register(struct ltt_transport
*transport
)
842 pthread_mutex_lock(&sessions_mutex
);
843 cds_list_add_tail(&transport
->node
, <t_transport_list
);
844 pthread_mutex_unlock(&sessions_mutex
);
848 * ltt_transport_unregister - LTT transport unregistration
849 * @transport: transport structure
851 void ltt_transport_unregister(struct ltt_transport
*transport
)
853 pthread_mutex_lock(&sessions_mutex
);
854 cds_list_del(&transport
->node
);
855 pthread_mutex_unlock(&sessions_mutex
);
859 void __attribute__((destructor
)) ltt_events_exit(void)
861 struct ltt_session
*session
, *tmpsession
;
863 cds_list_for_each_entry_safe(session
, tmpsession
, &sessions
, list
)
864 ltt_session_destroy(session
);