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.
14 #include <urcu/list.h>
15 #include <urcu/hlist.h>
17 #include <uuid/uuid.h>
28 #include <urcu/compiler.h>
29 #include <urcu/uatomic.h>
30 #include <urcu/arch.h>
32 #include <lttng/tracepoint.h>
33 #include <lttng/ust-events.h>
35 #include <usterr-signal-safe.h>
39 #include "ltt-tracer.h"
40 #include "ltt-tracer-core.h"
42 #include "../libringbuffer/shm.h"
46 * The sessions mutex is the centralized mutex across UST tracing
47 * control and probe registration. All operations within this file are
48 * called by the communication thread, under ust_lock protection.
50 static pthread_mutex_t sessions_mutex
= PTHREAD_MUTEX_INITIALIZER
;
54 pthread_mutex_lock(&sessions_mutex
);
59 pthread_mutex_unlock(&sessions_mutex
);
62 static CDS_LIST_HEAD(sessions
);
65 * Pending probes hash table, containing the registered ltt events for
66 * which tracepoint probes are still missing. Protected by the sessions
69 #define PENDING_PROBE_HASH_BITS 6
70 #define PENDING_PROBE_HASH_SIZE (1 << PENDING_PROBE_HASH_BITS)
71 static struct cds_hlist_head pending_probe_table
[PENDING_PROBE_HASH_SIZE
];
73 struct ust_pending_probe
{
74 struct ltt_event
*event
;
75 struct cds_hlist_node node
;
79 static void _ltt_event_destroy(struct ltt_event
*event
);
80 static void _ltt_loglevel_destroy(struct session_loglevel
*sl
);
81 static void _ltt_wildcard_destroy(struct session_wildcard
*sw
);
82 static void _ltt_channel_destroy(struct ltt_channel
*chan
);
83 static int _ltt_event_unregister(struct ltt_event
*event
);
85 int _ltt_event_metadata_statedump(struct ltt_session
*session
,
86 struct ltt_channel
*chan
,
87 struct ltt_event
*event
);
89 int _ltt_session_metadata_statedump(struct ltt_session
*session
);
92 * called at event creation if probe is missing.
93 * called with session mutex held.
96 int add_pending_probe(struct ltt_event
*event
, const char *name
)
98 struct cds_hlist_head
*head
;
99 struct ust_pending_probe
*e
;
100 size_t name_len
= strlen(name
);
103 if (name_len
> LTTNG_UST_SYM_NAME_LEN
- 1) {
104 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name
, LTTNG_UST_SYM_NAME_LEN
- 1);
105 name_len
= LTTNG_UST_SYM_NAME_LEN
- 1;
107 hash
= jhash(name
, name_len
, 0);
108 head
= &pending_probe_table
[hash
& (PENDING_PROBE_HASH_SIZE
- 1)];
109 e
= zmalloc(sizeof(struct ust_pending_probe
) + name_len
);
112 memcpy(&e
->name
[0], name
, name_len
+ 1);
113 e
->name
[name_len
] = '\0';
114 cds_hlist_add_head(&e
->node
, head
);
116 event
->pending_probe
= e
;
121 * remove a pending probe. called when at event teardown and when an
122 * event is fixed (probe is loaded).
123 * called with session mutex held.
126 void remove_pending_probe(struct ust_pending_probe
*e
)
130 cds_hlist_del(&e
->node
);
135 * Called at library load: connect the probe on the events pending on
137 * called with session mutex held.
139 int pending_probe_fix_events(const struct lttng_event_desc
*desc
)
141 struct cds_hlist_head
*head
;
142 struct cds_hlist_node
*node
, *p
;
143 struct ust_pending_probe
*e
;
144 const char *name
= desc
->name
;
146 struct lttng_ust_event event_param
;
147 size_t name_len
= strlen(name
);
151 * For this event, we need to lookup the loglevel. If active (in
152 * the active loglevels hash table), we must create the event.
154 if (desc
->loglevel
) {
155 const struct tracepoint_loglevel_entry
*ev_ll
;
156 struct loglevel_entry
*loglevel
;
158 ev_ll
= *desc
->loglevel
;
159 loglevel
= get_loglevel(ev_ll
->identifier
);
161 loglevel
= get_loglevel_value(ev_ll
->value
);
163 struct session_loglevel
*sl
;
165 cds_list_for_each_entry(sl
, &loglevel
->session_list
,
167 struct ltt_event
*ev
;
170 memcpy(&event_param
, &sl
->event_param
,
171 sizeof(event_param
));
172 memcpy(event_param
.name
,
174 sizeof(event_param
.name
));
176 ret
= ltt_event_create(sl
->chan
,
180 DBG("Error creating event");
183 cds_list_add(&ev
->loglevel_list
,
191 struct wildcard_entry
*wildcard
;
193 wildcard
= match_wildcard(desc
->name
);
194 if (strcmp(desc
->name
, "lttng_ust:metadata") && wildcard
) {
195 struct session_wildcard
*sw
;
197 cds_list_for_each_entry(sw
, &wildcard
->session_list
,
199 struct ltt_event
*ev
;
202 memcpy(&event_param
, &sw
->event_param
,
203 sizeof(event_param
));
204 memcpy(event_param
.name
,
206 sizeof(event_param
.name
));
208 ret
= ltt_event_create(sw
->chan
,
212 DBG("Error creating event");
215 cds_list_add(&ev
->wildcard_list
,
221 if (name_len
> LTTNG_UST_SYM_NAME_LEN
- 1) {
222 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name
, LTTNG_UST_SYM_NAME_LEN
- 1);
223 name_len
= LTTNG_UST_SYM_NAME_LEN
- 1;
225 hash
= jhash(name
, name_len
, 0);
226 head
= &pending_probe_table
[hash
& (PENDING_PROBE_HASH_SIZE
- 1)];
227 cds_hlist_for_each_entry_safe(e
, node
, p
, head
, node
) {
228 struct ltt_event
*event
;
229 struct ltt_channel
*chan
;
231 if (strncmp(name
, e
->name
, LTTNG_UST_SYM_NAME_LEN
- 1))
235 assert(!event
->desc
);
237 event
->pending_probe
= NULL
;
238 remove_pending_probe(e
);
239 ret
|= __tracepoint_probe_register(name
,
240 event
->desc
->probe_callback
,
244 event
->id
= chan
->free_event_id
++;
245 ret
|= _ltt_event_metadata_statedump(chan
->session
, chan
,
251 void synchronize_trace(void)
256 struct ltt_session
*ltt_session_create(void)
258 struct ltt_session
*session
;
260 session
= zmalloc(sizeof(struct ltt_session
));
263 CDS_INIT_LIST_HEAD(&session
->chan
);
264 CDS_INIT_LIST_HEAD(&session
->events
);
265 CDS_INIT_LIST_HEAD(&session
->loglevels
);
266 CDS_INIT_LIST_HEAD(&session
->wildcards
);
267 uuid_generate(session
->uuid
);
268 cds_list_add(&session
->list
, &sessions
);
272 void ltt_session_destroy(struct ltt_session
*session
)
274 struct ltt_channel
*chan
, *tmpchan
;
275 struct ltt_event
*event
, *tmpevent
;
276 struct session_loglevel
*loglevel
, *tmploglevel
;
277 struct session_wildcard
*wildcard
, *tmpwildcard
;
280 CMM_ACCESS_ONCE(session
->active
) = 0;
281 cds_list_for_each_entry(event
, &session
->events
, list
) {
282 ret
= _ltt_event_unregister(event
);
285 synchronize_trace(); /* Wait for in-flight events to complete */
286 cds_list_for_each_entry_safe(loglevel
, tmploglevel
, &session
->loglevels
, list
)
287 _ltt_loglevel_destroy(loglevel
);
288 cds_list_for_each_entry_safe(wildcard
, tmpwildcard
, &session
->wildcards
, list
)
289 _ltt_wildcard_destroy(wildcard
);
290 cds_list_for_each_entry_safe(event
, tmpevent
, &session
->events
, list
)
291 _ltt_event_destroy(event
);
292 cds_list_for_each_entry_safe(chan
, tmpchan
, &session
->chan
, list
)
293 _ltt_channel_destroy(chan
);
294 cds_list_del(&session
->list
);
298 int ltt_session_enable(struct ltt_session
*session
)
301 struct ltt_channel
*chan
;
303 if (session
->active
) {
309 * Snapshot the number of events per channel to know the type of header
312 cds_list_for_each_entry(chan
, &session
->chan
, list
) {
313 if (chan
->header_type
)
314 continue; /* don't change it if session stop/restart */
315 if (chan
->free_event_id
< 31)
316 chan
->header_type
= 1; /* compact */
318 chan
->header_type
= 2; /* large */
321 CMM_ACCESS_ONCE(session
->active
) = 1;
322 CMM_ACCESS_ONCE(session
->been_active
) = 1;
323 ret
= _ltt_session_metadata_statedump(session
);
325 CMM_ACCESS_ONCE(session
->active
) = 0;
330 int ltt_session_disable(struct ltt_session
*session
)
334 if (!session
->active
) {
338 CMM_ACCESS_ONCE(session
->active
) = 0;
343 int ltt_channel_enable(struct ltt_channel
*channel
)
347 if (channel
== channel
->session
->metadata
)
349 old
= uatomic_xchg(&channel
->enabled
, 1);
355 int ltt_channel_disable(struct ltt_channel
*channel
)
359 if (channel
== channel
->session
->metadata
)
361 old
= uatomic_xchg(&channel
->enabled
, 0);
367 int ltt_event_enable(struct ltt_event
*event
)
371 if (event
->chan
== event
->chan
->session
->metadata
)
373 old
= uatomic_xchg(&event
->enabled
, 1);
379 int ltt_event_disable(struct ltt_event
*event
)
383 if (event
->chan
== event
->chan
->session
->metadata
)
385 old
= uatomic_xchg(&event
->enabled
, 0);
391 struct ltt_channel
*ltt_channel_create(struct ltt_session
*session
,
392 const char *transport_name
,
394 size_t subbuf_size
, size_t num_subbuf
,
395 unsigned int switch_timer_interval
,
396 unsigned int read_timer_interval
,
397 int **shm_fd
, int **wait_fd
,
398 uint64_t **memory_map_size
,
399 struct ltt_channel
*chan_priv_init
)
401 struct ltt_channel
*chan
= NULL
;
402 struct ltt_transport
*transport
;
404 if (session
->been_active
)
405 goto active
; /* Refuse to add channel to active session */
406 transport
= ltt_transport_find(transport_name
);
408 DBG("LTTng transport %s not found\n",
412 chan_priv_init
->id
= session
->free_chan_id
++;
413 chan_priv_init
->session
= session
;
415 * Note: the channel creation op already writes into the packet
416 * headers. Therefore the "chan" information used as input
417 * should be already accessible.
419 chan
= transport
->ops
.channel_create("[lttng]", buf_addr
,
420 subbuf_size
, num_subbuf
, switch_timer_interval
,
421 read_timer_interval
, shm_fd
, wait_fd
,
422 memory_map_size
, chan_priv_init
);
426 chan
->ops
= &transport
->ops
;
427 cds_list_add(&chan
->list
, &session
->chan
);
437 * Only used internally at session destruction.
440 void _ltt_channel_destroy(struct ltt_channel
*chan
)
442 cds_list_del(&chan
->list
);
443 lttng_destroy_context(chan
->ctx
);
444 chan
->ops
->channel_destroy(chan
);
447 int ltt_loglevel_create(struct ltt_channel
*chan
,
448 struct lttng_ust_event
*event_param
,
449 struct session_loglevel
**_sl
)
451 struct session_loglevel
*sl
;
453 sl
= add_loglevel(event_param
->name
, chan
, event_param
);
454 if (!sl
|| IS_ERR(sl
)) {
462 void _ltt_loglevel_destroy(struct session_loglevel
*sl
)
464 _remove_loglevel(sl
);
467 int ltt_wildcard_create(struct ltt_channel
*chan
,
468 struct lttng_ust_event
*event_param
,
469 struct session_wildcard
**_sw
)
471 struct session_wildcard
*sw
;
473 sw
= add_wildcard(event_param
->name
, chan
, event_param
);
474 if (!sw
|| IS_ERR(sw
)) {
482 void _ltt_wildcard_destroy(struct session_wildcard
*sw
)
484 _remove_wildcard(sw
);
488 * Supports event creation while tracing session is active.
490 int ltt_event_create(struct ltt_channel
*chan
,
491 struct lttng_ust_event
*event_param
,
493 struct ltt_event
**_event
)
495 struct ltt_event
*event
;
498 if (chan
->used_event_id
== -1UL) {
503 * This is O(n^2) (for each event, the loop is called at event
504 * creation). Might require a hash if we have lots of events.
506 cds_list_for_each_entry(event
, &chan
->session
->events
, list
) {
507 if (event
->desc
&& !strncmp(event
->desc
->name
,
509 LTTNG_UST_SYM_NAME_LEN
- 1)) {
514 event
= zmalloc(sizeof(struct ltt_event
));
520 event
->filter
= filter
;
522 * used_event_id counts the maximum number of event IDs that can
523 * register if all probes register.
525 chan
->used_event_id
++;
527 event
->instrumentation
= event_param
->instrumentation
;
528 /* Populate ltt_event structure before tracepoint registration. */
530 switch (event_param
->instrumentation
) {
531 case LTTNG_UST_TRACEPOINT
:
532 event
->desc
= ltt_event_get(event_param
->name
);
534 ret
= __tracepoint_probe_register(event_param
->name
,
535 event
->desc
->probe_callback
,
539 event
->id
= chan
->free_event_id
++;
542 * If the probe is not present, event->desc stays NULL,
543 * waiting for the probe to register, and the event->id
546 ret
= add_pending_probe(event
, event_param
->name
);
548 goto add_pending_error
;
555 ret
= _ltt_event_metadata_statedump(chan
->session
, chan
, event
);
557 goto statedump_error
;
559 cds_list_add(&event
->list
, &chan
->session
->events
);
565 WARN_ON_ONCE(__tracepoint_probe_unregister(event_param
->name
,
566 event
->desc
->probe_callback
,
568 ltt_event_put(event
->desc
);
580 * Only used internally at session destruction.
582 int _ltt_event_unregister(struct ltt_event
*event
)
586 switch (event
->instrumentation
) {
587 case LTTNG_UST_TRACEPOINT
:
589 ret
= __tracepoint_probe_unregister(event
->desc
->name
,
590 event
->desc
->probe_callback
,
595 remove_pending_probe(event
->pending_probe
);
606 * Only used internally at session destruction.
609 void _ltt_event_destroy(struct ltt_event
*event
)
611 switch (event
->instrumentation
) {
612 case LTTNG_UST_TRACEPOINT
:
614 ltt_event_put(event
->desc
);
620 cds_list_del(&event
->list
);
621 lttng_destroy_context(event
->ctx
);
626 * We have exclusive access to our metadata buffer (protected by the
627 * ust_lock), so we can do racy operations such as looking for
628 * remaining space left in packet and write, since mutual exclusion
629 * protects us from concurrent writes.
631 int lttng_metadata_printf(struct ltt_session
*session
,
632 const char *fmt
, ...)
634 struct lttng_ust_lib_ring_buffer_ctx ctx
;
635 struct ltt_channel
*chan
= session
->metadata
;
637 int ret
= 0, waitret
;
638 size_t len
, reserve_len
, pos
;
641 WARN_ON_ONCE(!CMM_ACCESS_ONCE(session
->active
));
644 ret
= vasprintf(&str
, fmt
, ap
);
652 for (pos
= 0; pos
< len
; pos
+= reserve_len
) {
653 reserve_len
= min_t(size_t,
654 chan
->ops
->packet_avail_size(chan
->chan
, chan
->handle
),
656 lib_ring_buffer_ctx_init(&ctx
, chan
->chan
, NULL
, reserve_len
,
657 sizeof(char), -1, chan
->handle
);
659 * We don't care about metadata buffer's records lost
660 * count, because we always retry here. Report error if
661 * we need to bail out after timeout or being
664 waitret
= wait_cond_interruptible_timeout(
666 ret
= chan
->ops
->event_reserve(&ctx
, 0);
667 ret
!= -ENOBUFS
|| !ret
;
669 LTTNG_METADATA_TIMEOUT_MSEC
);
670 if (waitret
== -ETIMEDOUT
|| waitret
== -EINTR
|| ret
) {
671 DBG("LTTng: Failure to write metadata to buffers (%s)\n",
672 waitret
== -EINTR
? "interrupted" :
673 (ret
== -ENOBUFS
? "timeout" : "I/O error"));
674 if (waitret
== -EINTR
)
678 chan
->ops
->event_write(&ctx
, &str
[pos
], reserve_len
);
679 chan
->ops
->event_commit(&ctx
);
687 int _ltt_field_statedump(struct ltt_session
*session
,
688 const struct lttng_event_field
*field
)
692 switch (field
->type
.atype
) {
694 ret
= lttng_metadata_printf(session
,
695 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
696 field
->type
.u
.basic
.integer
.size
,
697 field
->type
.u
.basic
.integer
.alignment
,
698 field
->type
.u
.basic
.integer
.signedness
,
699 (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_none
)
701 : (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
704 field
->type
.u
.basic
.integer
.base
,
705 #if (BYTE_ORDER == BIG_ENDIAN)
706 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
708 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
713 ret
= lttng_metadata_printf(session
,
714 " floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
715 field
->type
.u
.basic
._float
.exp_dig
,
716 field
->type
.u
.basic
._float
.mant_dig
,
717 field
->type
.u
.basic
._float
.alignment
,
718 #if (BYTE_ORDER == BIG_ENDIAN)
719 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
721 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
726 ret
= lttng_metadata_printf(session
,
728 field
->type
.u
.basic
.enumeration
.name
,
733 const struct lttng_basic_type
*elem_type
;
735 elem_type
= &field
->type
.u
.array
.elem_type
;
736 ret
= lttng_metadata_printf(session
,
737 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
738 elem_type
->u
.basic
.integer
.size
,
739 elem_type
->u
.basic
.integer
.alignment
,
740 elem_type
->u
.basic
.integer
.signedness
,
741 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
743 : (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
746 elem_type
->u
.basic
.integer
.base
,
747 #if (BYTE_ORDER == BIG_ENDIAN)
748 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
750 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
752 field
->name
, field
->type
.u
.array
.length
);
757 const struct lttng_basic_type
*elem_type
;
758 const struct lttng_basic_type
*length_type
;
760 elem_type
= &field
->type
.u
.sequence
.elem_type
;
761 length_type
= &field
->type
.u
.sequence
.length_type
;
762 ret
= lttng_metadata_printf(session
,
763 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
764 length_type
->u
.basic
.integer
.size
,
765 (unsigned int) length_type
->u
.basic
.integer
.alignment
,
766 length_type
->u
.basic
.integer
.signedness
,
767 (length_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
769 : ((length_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
772 length_type
->u
.basic
.integer
.base
,
773 #if (BYTE_ORDER == BIG_ENDIAN)
774 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
776 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
782 ret
= lttng_metadata_printf(session
,
783 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
784 elem_type
->u
.basic
.integer
.size
,
785 (unsigned int) elem_type
->u
.basic
.integer
.alignment
,
786 elem_type
->u
.basic
.integer
.signedness
,
787 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
789 : ((elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
792 elem_type
->u
.basic
.integer
.base
,
793 #if (BYTE_ORDER == BIG_ENDIAN)
794 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
796 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
804 /* Default encoding is UTF8 */
805 ret
= lttng_metadata_printf(session
,
807 field
->type
.u
.basic
.string
.encoding
== lttng_encode_ASCII
?
808 " { encoding = ASCII; }" : "",
819 int _ltt_context_metadata_statedump(struct ltt_session
*session
,
820 struct lttng_ctx
*ctx
)
827 for (i
= 0; i
< ctx
->nr_fields
; i
++) {
828 const struct lttng_ctx_field
*field
= &ctx
->fields
[i
];
830 ret
= _ltt_field_statedump(session
, &field
->event_field
);
838 int _ltt_fields_metadata_statedump(struct ltt_session
*session
,
839 struct ltt_event
*event
)
841 const struct lttng_event_desc
*desc
= event
->desc
;
845 for (i
= 0; i
< desc
->nr_fields
; i
++) {
846 const struct lttng_event_field
*field
= &desc
->fields
[i
];
848 ret
= _ltt_field_statedump(session
, field
);
856 int _ltt_event_metadata_statedump(struct ltt_session
*session
,
857 struct ltt_channel
*chan
,
858 struct ltt_event
*event
)
862 if (event
->metadata_dumped
|| !CMM_ACCESS_ONCE(session
->active
))
864 if (chan
== session
->metadata
)
867 * Don't print events for which probe load is pending.
872 ret
= lttng_metadata_printf(session
,
876 " stream_id = %u;\n",
883 if (event
->desc
->loglevel
) {
884 const struct tracepoint_loglevel_entry
*ll_entry
;
886 ll_entry
= *event
->desc
->loglevel
;
887 ret
= lttng_metadata_printf(session
,
888 " loglevel.identifier = \"%s\";\n"
889 " loglevel.value = %lld;\n",
890 ll_entry
->identifier
,
891 (long long) ll_entry
->value
);
897 ret
= lttng_metadata_printf(session
,
898 " context := struct {\n");
902 ret
= _ltt_context_metadata_statedump(session
, event
->ctx
);
906 ret
= lttng_metadata_printf(session
,
912 ret
= lttng_metadata_printf(session
,
913 " fields := struct {\n"
918 ret
= _ltt_fields_metadata_statedump(session
, event
);
923 * LTTng space reservation can only reserve multiples of the
926 ret
= lttng_metadata_printf(session
,
932 event
->metadata_dumped
= 1;
939 int _ltt_channel_metadata_statedump(struct ltt_session
*session
,
940 struct ltt_channel
*chan
)
944 if (chan
->metadata_dumped
|| !CMM_ACCESS_ONCE(session
->active
))
946 if (chan
== session
->metadata
)
949 WARN_ON_ONCE(!chan
->header_type
);
950 ret
= lttng_metadata_printf(session
,
953 " event.header := %s;\n"
954 " packet.context := struct packet_context;\n",
956 chan
->header_type
== 1 ? "struct event_header_compact" :
957 "struct event_header_large");
962 ret
= lttng_metadata_printf(session
,
963 " event.context := struct {\n");
967 ret
= _ltt_context_metadata_statedump(session
, chan
->ctx
);
971 ret
= lttng_metadata_printf(session
,
977 ret
= lttng_metadata_printf(session
,
980 chan
->metadata_dumped
= 1;
986 int _ltt_stream_packet_context_declare(struct ltt_session
*session
)
988 return lttng_metadata_printf(session
,
989 "struct packet_context {\n"
990 " uint64_clock_monotonic_t timestamp_begin;\n"
991 " uint64_clock_monotonic_t timestamp_end;\n"
992 " uint32_t events_discarded;\n"
993 " uint32_t content_size;\n"
994 " uint32_t packet_size;\n"
995 " uint32_t cpu_id;\n"
1002 * id: range: 0 - 30.
1003 * id 31 is reserved to indicate an extended header.
1006 * id: range: 0 - 65534.
1007 * id 65535 is reserved to indicate an extended header.
1010 int _ltt_event_header_declare(struct ltt_session
*session
)
1012 return lttng_metadata_printf(session
,
1013 "struct event_header_compact {\n"
1014 " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
1017 " uint27_clock_monotonic_t timestamp;\n"
1021 " uint64_clock_monotonic_t timestamp;\n"
1026 "struct event_header_large {\n"
1027 " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
1030 " uint32_clock_monotonic_t timestamp;\n"
1034 " uint64_clock_monotonic_t timestamp;\n"
1038 lttng_alignof(uint32_t) * CHAR_BIT
,
1039 lttng_alignof(uint16_t) * CHAR_BIT
1044 * Approximation of NTP time of day to clock monotonic correlation,
1045 * taken at start of trace.
1046 * Yes, this is only an approximation. Yes, we can (and will) do better
1047 * in future versions.
1050 uint64_t measure_clock_offset(void)
1052 uint64_t offset
, monotonic
[2], realtime
;
1053 struct timespec rts
= { 0, 0 };
1056 monotonic
[0] = trace_clock_read64();
1057 ret
= clock_gettime(CLOCK_REALTIME
, &rts
);
1060 monotonic
[1] = trace_clock_read64();
1061 offset
= (monotonic
[0] + monotonic
[1]) >> 1;
1062 realtime
= rts
.tv_sec
* 1000000000ULL;
1063 realtime
+= rts
.tv_nsec
;
1064 offset
= realtime
- offset
;
1069 * Output metadata into this session's metadata buffers.
1072 int _ltt_session_metadata_statedump(struct ltt_session
*session
)
1074 unsigned char *uuid_c
= session
->uuid
;
1075 char uuid_s
[37], clock_uuid_s
[CLOCK_UUID_LEN
];
1076 struct ltt_channel
*chan
;
1077 struct ltt_event
*event
;
1080 if (!CMM_ACCESS_ONCE(session
->active
))
1082 if (session
->metadata_dumped
)
1084 if (!session
->metadata
) {
1085 DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
1089 snprintf(uuid_s
, sizeof(uuid_s
),
1090 "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
1091 uuid_c
[0], uuid_c
[1], uuid_c
[2], uuid_c
[3],
1092 uuid_c
[4], uuid_c
[5], uuid_c
[6], uuid_c
[7],
1093 uuid_c
[8], uuid_c
[9], uuid_c
[10], uuid_c
[11],
1094 uuid_c
[12], uuid_c
[13], uuid_c
[14], uuid_c
[15]);
1096 ret
= lttng_metadata_printf(session
,
1097 "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
1098 "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
1099 "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
1100 "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
1101 "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
1102 "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
1108 " byte_order = %s;\n"
1109 " packet.header := struct {\n"
1110 " uint32_t magic;\n"
1111 " uint8_t uuid[16];\n"
1112 " uint32_t stream_id;\n"
1115 lttng_alignof(uint8_t) * CHAR_BIT
,
1116 lttng_alignof(uint16_t) * CHAR_BIT
,
1117 lttng_alignof(uint32_t) * CHAR_BIT
,
1118 lttng_alignof(uint64_t) * CHAR_BIT
,
1122 #if (BYTE_ORDER == BIG_ENDIAN)
1131 ret
= lttng_metadata_printf(session
,
1139 if (!trace_clock_uuid(clock_uuid_s
)) {
1140 ret
= lttng_metadata_printf(session
,
1141 " uuid = \"%s\";\n",
1148 ret
= lttng_metadata_printf(session
,
1149 " description = \"Monotonic Clock\";\n"
1150 " freq = %" PRIu64
"; /* Frequency, in Hz */\n"
1151 " /* clock value offset from Epoch is: offset * (1/freq) */\n"
1152 " offset = %" PRIu64
";\n"
1155 measure_clock_offset()
1160 ret
= lttng_metadata_printf(session
,
1161 "typealias integer {\n"
1162 " size = 27; align = 1; signed = false;\n"
1163 " map = clock.monotonic.value;\n"
1164 "} := uint27_clock_monotonic_t;\n"
1166 "typealias integer {\n"
1167 " size = 32; align = %u; signed = false;\n"
1168 " map = clock.monotonic.value;\n"
1169 "} := uint32_clock_monotonic_t;\n"
1171 "typealias integer {\n"
1172 " size = 64; align = %u; signed = false;\n"
1173 " map = clock.monotonic.value;\n"
1174 "} := uint64_clock_monotonic_t;\n\n",
1175 lttng_alignof(uint32_t) * CHAR_BIT
,
1176 lttng_alignof(uint64_t) * CHAR_BIT
1181 ret
= _ltt_stream_packet_context_declare(session
);
1185 ret
= _ltt_event_header_declare(session
);
1190 cds_list_for_each_entry(chan
, &session
->chan
, list
) {
1191 ret
= _ltt_channel_metadata_statedump(session
, chan
);
1196 cds_list_for_each_entry(event
, &session
->events
, list
) {
1197 ret
= _ltt_event_metadata_statedump(session
, event
->chan
, event
);
1201 session
->metadata_dumped
= 1;
1206 void lttng_ust_events_exit(void)
1208 struct ltt_session
*session
, *tmpsession
;
1210 cds_list_for_each_entry_safe(session
, tmpsession
, &sessions
, list
)
1211 ltt_session_destroy(session
);