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
24 * This page_alloc.h wrapper needs to be included before gfpflags.h because it
25 * overrides a function with a define.
27 #include "wrapper/page_alloc.h"
29 #include <linux/module.h>
30 #include <linux/list.h>
31 #include <linux/mutex.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/jiffies.h>
35 #include <linux/utsname.h>
36 #include <linux/err.h>
37 #include <linux/vmalloc.h>
39 #include "wrapper/uuid.h"
40 #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
41 #include "wrapper/random.h"
42 #include "wrapper/tracepoint.h"
43 #include "lttng-kernel-version.h"
44 #include "lttng-events.h"
45 #include "lttng-tracer.h"
46 #include "lttng-abi-old.h"
48 #define METADATA_CACHE_DEFAULT_SIZE 4096
50 static LIST_HEAD(sessions
);
51 static LIST_HEAD(lttng_transport_list
);
53 * Protect the sessions and metadata caches.
55 static DEFINE_MUTEX(sessions_mutex
);
56 static struct kmem_cache
*event_cache
;
58 static void _lttng_event_destroy(struct lttng_event
*event
);
59 static void _lttng_channel_destroy(struct lttng_channel
*chan
);
60 static int _lttng_event_unregister(struct lttng_event
*event
);
62 int _lttng_event_metadata_statedump(struct lttng_session
*session
,
63 struct lttng_channel
*chan
,
64 struct lttng_event
*event
);
66 int _lttng_session_metadata_statedump(struct lttng_session
*session
);
68 void _lttng_metadata_channel_hangup(struct lttng_metadata_stream
*stream
);
70 void synchronize_trace(void)
73 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0))
74 #ifdef CONFIG_PREEMPT_RT_FULL
77 #else /* (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)) */
78 #ifdef CONFIG_PREEMPT_RT
81 #endif /* (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)) */
84 struct lttng_session
*lttng_session_create(void)
86 struct lttng_session
*session
;
87 struct lttng_metadata_cache
*metadata_cache
;
89 mutex_lock(&sessions_mutex
);
90 session
= kzalloc(sizeof(struct lttng_session
), GFP_KERNEL
);
93 INIT_LIST_HEAD(&session
->chan
);
94 INIT_LIST_HEAD(&session
->events
);
95 uuid_le_gen(&session
->uuid
);
97 metadata_cache
= kzalloc(sizeof(struct lttng_metadata_cache
),
100 goto err_free_session
;
101 metadata_cache
->data
= vzalloc(METADATA_CACHE_DEFAULT_SIZE
);
102 if (!metadata_cache
->data
)
104 metadata_cache
->cache_alloc
= METADATA_CACHE_DEFAULT_SIZE
;
105 kref_init(&metadata_cache
->refcount
);
106 mutex_init(&metadata_cache
->lock
);
107 session
->metadata_cache
= metadata_cache
;
108 INIT_LIST_HEAD(&metadata_cache
->metadata_stream
);
109 memcpy(&metadata_cache
->uuid
, &session
->uuid
,
110 sizeof(metadata_cache
->uuid
));
111 list_add(&session
->list
, &sessions
);
112 mutex_unlock(&sessions_mutex
);
116 kfree(metadata_cache
);
120 mutex_unlock(&sessions_mutex
);
124 void metadata_cache_destroy(struct kref
*kref
)
126 struct lttng_metadata_cache
*cache
=
127 container_of(kref
, struct lttng_metadata_cache
, refcount
);
132 void lttng_session_destroy(struct lttng_session
*session
)
134 struct lttng_channel
*chan
, *tmpchan
;
135 struct lttng_event
*event
, *tmpevent
;
136 struct lttng_metadata_stream
*metadata_stream
;
139 mutex_lock(&sessions_mutex
);
140 ACCESS_ONCE(session
->active
) = 0;
141 list_for_each_entry(chan
, &session
->chan
, list
) {
142 ret
= lttng_syscalls_unregister(chan
);
145 list_for_each_entry(event
, &session
->events
, list
) {
146 ret
= _lttng_event_unregister(event
);
149 synchronize_trace(); /* Wait for in-flight events to complete */
150 list_for_each_entry_safe(event
, tmpevent
, &session
->events
, list
)
151 _lttng_event_destroy(event
);
152 list_for_each_entry_safe(chan
, tmpchan
, &session
->chan
, list
) {
153 BUG_ON(chan
->channel_type
== METADATA_CHANNEL
);
154 _lttng_channel_destroy(chan
);
156 list_for_each_entry(metadata_stream
, &session
->metadata_cache
->metadata_stream
, list
)
157 _lttng_metadata_channel_hangup(metadata_stream
);
158 kref_put(&session
->metadata_cache
->refcount
, metadata_cache_destroy
);
159 list_del(&session
->list
);
160 mutex_unlock(&sessions_mutex
);
164 int lttng_session_enable(struct lttng_session
*session
)
167 struct lttng_channel
*chan
;
169 mutex_lock(&sessions_mutex
);
170 if (session
->active
) {
176 * Snapshot the number of events per channel to know the type of header
179 list_for_each_entry(chan
, &session
->chan
, list
) {
180 if (chan
->header_type
)
181 continue; /* don't change it if session stop/restart */
182 if (chan
->free_event_id
< 31)
183 chan
->header_type
= 1; /* compact */
185 chan
->header_type
= 2; /* large */
188 ACCESS_ONCE(session
->active
) = 1;
189 ACCESS_ONCE(session
->been_active
) = 1;
190 ret
= _lttng_session_metadata_statedump(session
);
192 ACCESS_ONCE(session
->active
) = 0;
195 ret
= lttng_statedump_start(session
);
197 ACCESS_ONCE(session
->active
) = 0;
199 mutex_unlock(&sessions_mutex
);
203 int lttng_session_disable(struct lttng_session
*session
)
207 mutex_lock(&sessions_mutex
);
208 if (!session
->active
) {
212 ACCESS_ONCE(session
->active
) = 0;
214 mutex_unlock(&sessions_mutex
);
218 int lttng_channel_enable(struct lttng_channel
*channel
)
222 if (channel
->channel_type
== METADATA_CHANNEL
)
224 old
= xchg(&channel
->enabled
, 1);
230 int lttng_channel_disable(struct lttng_channel
*channel
)
234 if (channel
->channel_type
== METADATA_CHANNEL
)
236 old
= xchg(&channel
->enabled
, 0);
242 int lttng_event_enable(struct lttng_event
*event
)
246 if (event
->chan
->channel_type
== METADATA_CHANNEL
)
248 old
= xchg(&event
->enabled
, 1);
254 int lttng_event_disable(struct lttng_event
*event
)
258 if (event
->chan
->channel_type
== METADATA_CHANNEL
)
260 old
= xchg(&event
->enabled
, 0);
266 static struct lttng_transport
*lttng_transport_find(const char *name
)
268 struct lttng_transport
*transport
;
270 list_for_each_entry(transport
, <tng_transport_list
, node
) {
271 if (!strcmp(transport
->name
, name
))
277 struct lttng_channel
*lttng_channel_create(struct lttng_session
*session
,
278 const char *transport_name
,
280 size_t subbuf_size
, size_t num_subbuf
,
281 unsigned int switch_timer_interval
,
282 unsigned int read_timer_interval
,
283 enum channel_type channel_type
)
285 struct lttng_channel
*chan
;
286 struct lttng_transport
*transport
= NULL
;
288 mutex_lock(&sessions_mutex
);
289 if (session
->been_active
&& channel_type
!= METADATA_CHANNEL
)
290 goto active
; /* Refuse to add channel to active session */
291 transport
= lttng_transport_find(transport_name
);
293 printk(KERN_WARNING
"LTTng transport %s not found\n",
297 if (!try_module_get(transport
->owner
)) {
298 printk(KERN_WARNING
"LTT : Can't lock transport module.\n");
301 chan
= kzalloc(sizeof(struct lttng_channel
), GFP_KERNEL
);
304 chan
->session
= session
;
305 chan
->id
= session
->free_chan_id
++;
306 chan
->ops
= &transport
->ops
;
308 * Note: the channel creation op already writes into the packet
309 * headers. Therefore the "chan" information used as input
310 * should be already accessible.
312 chan
->chan
= transport
->ops
.channel_create(transport_name
,
313 chan
, buf_addr
, subbuf_size
, num_subbuf
,
314 switch_timer_interval
, read_timer_interval
);
318 chan
->transport
= transport
;
319 chan
->channel_type
= channel_type
;
320 list_add(&chan
->list
, &session
->chan
);
321 mutex_unlock(&sessions_mutex
);
328 module_put(transport
->owner
);
331 mutex_unlock(&sessions_mutex
);
336 * Only used internally at session destruction for per-cpu channels, and
337 * when metadata channel is released.
338 * Needs to be called with sessions mutex held.
341 void _lttng_channel_destroy(struct lttng_channel
*chan
)
343 chan
->ops
->channel_destroy(chan
->chan
);
344 module_put(chan
->transport
->owner
);
345 list_del(&chan
->list
);
346 lttng_destroy_context(chan
->ctx
);
350 void lttng_metadata_channel_destroy(struct lttng_channel
*chan
)
352 BUG_ON(chan
->channel_type
!= METADATA_CHANNEL
);
354 /* Protect the metadata cache with the sessions_mutex. */
355 mutex_lock(&sessions_mutex
);
356 _lttng_channel_destroy(chan
);
357 mutex_unlock(&sessions_mutex
);
359 EXPORT_SYMBOL_GPL(lttng_metadata_channel_destroy
);
362 void _lttng_metadata_channel_hangup(struct lttng_metadata_stream
*stream
)
364 stream
->finalized
= 1;
365 wake_up_interruptible(&stream
->read_wait
);
369 * Supports event creation while tracing session is active.
371 struct lttng_event
*lttng_event_create(struct lttng_channel
*chan
,
372 struct lttng_kernel_event
*event_param
,
374 const struct lttng_event_desc
*internal_desc
)
376 struct lttng_event
*event
;
379 mutex_lock(&sessions_mutex
);
380 if (chan
->free_event_id
== -1U) {
385 * This is O(n^2) (for each event, the loop is called at event
386 * creation). Might require a hash if we have lots of events.
388 list_for_each_entry(event
, &chan
->session
->events
, list
) {
389 if (!strcmp(event
->desc
->name
, event_param
->name
)) {
391 * Allow events with the same name to appear in
392 * different channels.
394 if (event
->chan
== chan
) {
400 event
= kmem_cache_zalloc(event_cache
, GFP_KERNEL
);
406 event
->filter
= filter
;
407 event
->id
= chan
->free_event_id
++;
409 event
->instrumentation
= event_param
->instrumentation
;
410 /* Populate lttng_event structure before tracepoint registration. */
412 switch (event_param
->instrumentation
) {
413 case LTTNG_KERNEL_TRACEPOINT
:
414 event
->desc
= lttng_event_get(event_param
->name
);
419 ret
= lttng_wrapper_tracepoint_probe_register(event
->desc
->kname
,
420 event
->desc
->probe_callback
,
427 case LTTNG_KERNEL_KPROBE
:
428 ret
= lttng_kprobes_register(event_param
->name
,
429 event_param
->u
.kprobe
.symbol_name
,
430 event_param
->u
.kprobe
.offset
,
431 event_param
->u
.kprobe
.addr
,
437 ret
= try_module_get(event
->desc
->owner
);
440 case LTTNG_KERNEL_KRETPROBE
:
442 struct lttng_event
*event_return
;
444 /* kretprobe defines 2 events */
446 kmem_cache_zalloc(event_cache
, GFP_KERNEL
);
451 event_return
->chan
= chan
;
452 event_return
->filter
= filter
;
453 event_return
->id
= chan
->free_event_id
++;
454 event_return
->enabled
= 1;
455 event_return
->instrumentation
= event_param
->instrumentation
;
457 * Populate lttng_event structure before kretprobe registration.
460 ret
= lttng_kretprobes_register(event_param
->name
,
461 event_param
->u
.kretprobe
.symbol_name
,
462 event_param
->u
.kretprobe
.offset
,
463 event_param
->u
.kretprobe
.addr
,
464 event
, event_return
);
466 kmem_cache_free(event_cache
, event_return
);
470 /* Take 2 refs on the module: one per event. */
471 ret
= try_module_get(event
->desc
->owner
);
473 ret
= try_module_get(event
->desc
->owner
);
475 ret
= _lttng_event_metadata_statedump(chan
->session
, chan
,
477 WARN_ON_ONCE(ret
> 0);
479 kmem_cache_free(event_cache
, event_return
);
480 module_put(event
->desc
->owner
);
481 module_put(event
->desc
->owner
);
482 goto statedump_error
;
484 list_add(&event_return
->list
, &chan
->session
->events
);
487 case LTTNG_KERNEL_FUNCTION
:
488 ret
= lttng_ftrace_register(event_param
->name
,
489 event_param
->u
.ftrace
.symbol_name
,
494 ret
= try_module_get(event
->desc
->owner
);
497 case LTTNG_KERNEL_NOOP
:
498 event
->desc
= internal_desc
;
509 ret
= _lttng_event_metadata_statedump(chan
->session
, chan
, event
);
510 WARN_ON_ONCE(ret
> 0);
512 goto statedump_error
;
514 list_add(&event
->list
, &chan
->session
->events
);
515 mutex_unlock(&sessions_mutex
);
519 /* If a statedump error occurs, events will not be readable. */
521 kmem_cache_free(event_cache
, event
);
525 mutex_unlock(&sessions_mutex
);
530 * Only used internally at session destruction.
532 int _lttng_event_unregister(struct lttng_event
*event
)
536 switch (event
->instrumentation
) {
537 case LTTNG_KERNEL_TRACEPOINT
:
538 ret
= lttng_wrapper_tracepoint_probe_unregister(event
->desc
->kname
,
539 event
->desc
->probe_callback
,
544 case LTTNG_KERNEL_KPROBE
:
545 lttng_kprobes_unregister(event
);
548 case LTTNG_KERNEL_KRETPROBE
:
549 lttng_kretprobes_unregister(event
);
552 case LTTNG_KERNEL_FUNCTION
:
553 lttng_ftrace_unregister(event
);
556 case LTTNG_KERNEL_NOOP
:
566 * Only used internally at session destruction.
569 void _lttng_event_destroy(struct lttng_event
*event
)
571 switch (event
->instrumentation
) {
572 case LTTNG_KERNEL_TRACEPOINT
:
573 lttng_event_put(event
->desc
);
575 case LTTNG_KERNEL_KPROBE
:
576 module_put(event
->desc
->owner
);
577 lttng_kprobes_destroy_private(event
);
579 case LTTNG_KERNEL_KRETPROBE
:
580 module_put(event
->desc
->owner
);
581 lttng_kretprobes_destroy_private(event
);
583 case LTTNG_KERNEL_FUNCTION
:
584 module_put(event
->desc
->owner
);
585 lttng_ftrace_destroy_private(event
);
587 case LTTNG_KERNEL_NOOP
:
592 list_del(&event
->list
);
593 lttng_destroy_context(event
->ctx
);
594 kmem_cache_free(event_cache
, event
);
598 * Serialize at most one packet worth of metadata into a metadata
600 * We grab the metadata cache mutex to get exclusive access to our metadata
601 * buffer and to the metadata cache. Exclusive access to the metadata buffer
602 * allows us to do racy operations such as looking for remaining space left in
603 * packet and write, since mutual exclusion protects us from concurrent writes.
604 * Mutual exclusion on the metadata cache allow us to read the cache content
605 * without racing against reallocation of the cache by updates.
606 * Returns the number of bytes written in the channel, 0 if no data
607 * was written and a negative value on error.
609 int lttng_metadata_output_channel(struct lttng_metadata_stream
*stream
,
610 struct channel
*chan
)
612 struct lib_ring_buffer_ctx ctx
;
614 size_t len
, reserve_len
;
617 * Ensure we support mutiple get_next / put sequences followed by
618 * put_next. The metadata cache lock protects reading the metadata
619 * cache. It can indeed be read concurrently by "get_next_subbuf" and
620 * "flush" operations on the buffer invoked by different processes.
621 * Moreover, since the metadata cache memory can be reallocated, we
622 * need to have exclusive access against updates even though we only
625 mutex_lock(&stream
->metadata_cache
->lock
);
626 WARN_ON(stream
->metadata_in
< stream
->metadata_out
);
627 if (stream
->metadata_in
!= stream
->metadata_out
)
630 len
= stream
->metadata_cache
->metadata_written
-
634 reserve_len
= min_t(size_t,
635 stream
->transport
->ops
.packet_avail_size(chan
),
637 lib_ring_buffer_ctx_init(&ctx
, chan
, NULL
, reserve_len
,
640 * If reservation failed, return an error to the caller.
642 ret
= stream
->transport
->ops
.event_reserve(&ctx
, 0);
644 printk(KERN_WARNING
"LTTng: Metadata event reservation failed\n");
647 stream
->transport
->ops
.event_write(&ctx
,
648 stream
->metadata_cache
->data
+ stream
->metadata_in
,
650 stream
->transport
->ops
.event_commit(&ctx
);
651 stream
->metadata_in
+= reserve_len
;
655 mutex_unlock(&stream
->metadata_cache
->lock
);
660 * Write the metadata to the metadata cache.
661 * Must be called with sessions_mutex held.
662 * The metadata cache lock protects us from concurrent read access from
663 * thread outputting metadata content to ring buffer.
665 int lttng_metadata_printf(struct lttng_session
*session
,
666 const char *fmt
, ...)
671 struct lttng_metadata_stream
*stream
;
673 WARN_ON_ONCE(!ACCESS_ONCE(session
->active
));
676 str
= kvasprintf(GFP_KERNEL
, fmt
, ap
);
682 mutex_lock(&session
->metadata_cache
->lock
);
683 if (session
->metadata_cache
->metadata_written
+ len
>
684 session
->metadata_cache
->cache_alloc
) {
685 char *tmp_cache_realloc
;
686 unsigned int tmp_cache_alloc_size
;
688 tmp_cache_alloc_size
= max_t(unsigned int,
689 session
->metadata_cache
->cache_alloc
+ len
,
690 session
->metadata_cache
->cache_alloc
<< 1);
691 tmp_cache_realloc
= vzalloc(tmp_cache_alloc_size
);
692 if (!tmp_cache_realloc
)
694 if (session
->metadata_cache
->data
) {
695 memcpy(tmp_cache_realloc
,
696 session
->metadata_cache
->data
,
697 session
->metadata_cache
->cache_alloc
);
698 vfree(session
->metadata_cache
->data
);
701 session
->metadata_cache
->cache_alloc
= tmp_cache_alloc_size
;
702 session
->metadata_cache
->data
= tmp_cache_realloc
;
704 memcpy(session
->metadata_cache
->data
+
705 session
->metadata_cache
->metadata_written
,
707 session
->metadata_cache
->metadata_written
+= len
;
708 mutex_unlock(&session
->metadata_cache
->lock
);
711 list_for_each_entry(stream
, &session
->metadata_cache
->metadata_stream
, list
)
712 wake_up_interruptible(&stream
->read_wait
);
717 mutex_unlock(&session
->metadata_cache
->lock
);
723 * Must be called with sessions_mutex held.
726 int _lttng_field_statedump(struct lttng_session
*session
,
727 const struct lttng_event_field
*field
)
731 switch (field
->type
.atype
) {
733 ret
= lttng_metadata_printf(session
,
734 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
735 field
->type
.u
.basic
.integer
.size
,
736 field
->type
.u
.basic
.integer
.alignment
,
737 field
->type
.u
.basic
.integer
.signedness
,
738 (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_none
)
740 : (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
743 field
->type
.u
.basic
.integer
.base
,
745 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
747 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
752 ret
= lttng_metadata_printf(session
,
754 field
->type
.u
.basic
.enumeration
.name
,
759 const struct lttng_basic_type
*elem_type
;
761 elem_type
= &field
->type
.u
.array
.elem_type
;
762 ret
= lttng_metadata_printf(session
,
763 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
764 elem_type
->u
.basic
.integer
.size
,
765 elem_type
->u
.basic
.integer
.alignment
,
766 elem_type
->u
.basic
.integer
.signedness
,
767 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
769 : (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
772 elem_type
->u
.basic
.integer
.base
,
774 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
776 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
778 field
->name
, field
->type
.u
.array
.length
);
783 const struct lttng_basic_type
*elem_type
;
784 const struct lttng_basic_type
*length_type
;
786 elem_type
= &field
->type
.u
.sequence
.elem_type
;
787 length_type
= &field
->type
.u
.sequence
.length_type
;
788 ret
= lttng_metadata_printf(session
,
789 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
790 length_type
->u
.basic
.integer
.size
,
791 (unsigned int) length_type
->u
.basic
.integer
.alignment
,
792 length_type
->u
.basic
.integer
.signedness
,
793 (length_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
795 : ((length_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
798 length_type
->u
.basic
.integer
.base
,
800 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
802 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
808 ret
= lttng_metadata_printf(session
,
809 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
810 elem_type
->u
.basic
.integer
.size
,
811 (unsigned int) elem_type
->u
.basic
.integer
.alignment
,
812 elem_type
->u
.basic
.integer
.signedness
,
813 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
815 : ((elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
818 elem_type
->u
.basic
.integer
.base
,
820 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
822 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
830 /* Default encoding is UTF8 */
831 ret
= lttng_metadata_printf(session
,
833 field
->type
.u
.basic
.string
.encoding
== lttng_encode_ASCII
?
834 " { encoding = ASCII; }" : "",
845 int _lttng_context_metadata_statedump(struct lttng_session
*session
,
846 struct lttng_ctx
*ctx
)
853 for (i
= 0; i
< ctx
->nr_fields
; i
++) {
854 const struct lttng_ctx_field
*field
= &ctx
->fields
[i
];
856 ret
= _lttng_field_statedump(session
, &field
->event_field
);
864 int _lttng_fields_metadata_statedump(struct lttng_session
*session
,
865 struct lttng_event
*event
)
867 const struct lttng_event_desc
*desc
= event
->desc
;
871 for (i
= 0; i
< desc
->nr_fields
; i
++) {
872 const struct lttng_event_field
*field
= &desc
->fields
[i
];
874 ret
= _lttng_field_statedump(session
, field
);
882 * Must be called with sessions_mutex held.
885 int _lttng_event_metadata_statedump(struct lttng_session
*session
,
886 struct lttng_channel
*chan
,
887 struct lttng_event
*event
)
891 if (event
->metadata_dumped
|| !ACCESS_ONCE(session
->active
))
893 if (chan
->channel_type
== METADATA_CHANNEL
)
896 ret
= lttng_metadata_printf(session
,
900 " stream_id = %u;\n",
908 ret
= lttng_metadata_printf(session
,
909 " context := struct {\n");
913 ret
= _lttng_context_metadata_statedump(session
, event
->ctx
);
917 ret
= lttng_metadata_printf(session
,
923 ret
= lttng_metadata_printf(session
,
924 " fields := struct {\n"
929 ret
= _lttng_fields_metadata_statedump(session
, event
);
934 * LTTng space reservation can only reserve multiples of the
937 ret
= lttng_metadata_printf(session
,
943 event
->metadata_dumped
= 1;
950 * Must be called with sessions_mutex held.
953 int _lttng_channel_metadata_statedump(struct lttng_session
*session
,
954 struct lttng_channel
*chan
)
958 if (chan
->metadata_dumped
|| !ACCESS_ONCE(session
->active
))
961 if (chan
->channel_type
== METADATA_CHANNEL
)
964 WARN_ON_ONCE(!chan
->header_type
);
965 ret
= lttng_metadata_printf(session
,
968 " event.header := %s;\n"
969 " packet.context := struct packet_context;\n",
971 chan
->header_type
== 1 ? "struct event_header_compact" :
972 "struct event_header_large");
977 ret
= lttng_metadata_printf(session
,
978 " event.context := struct {\n");
982 ret
= _lttng_context_metadata_statedump(session
, chan
->ctx
);
986 ret
= lttng_metadata_printf(session
,
992 ret
= lttng_metadata_printf(session
,
995 chan
->metadata_dumped
= 1;
1001 * Must be called with sessions_mutex held.
1004 int _lttng_stream_packet_context_declare(struct lttng_session
*session
)
1006 return lttng_metadata_printf(session
,
1007 "struct packet_context {\n"
1008 " uint64_clock_monotonic_t timestamp_begin;\n"
1009 " uint64_clock_monotonic_t timestamp_end;\n"
1010 " uint64_t content_size;\n"
1011 " uint64_t packet_size;\n"
1012 " unsigned long events_discarded;\n"
1013 " uint32_t cpu_id;\n"
1020 * id: range: 0 - 30.
1021 * id 31 is reserved to indicate an extended header.
1024 * id: range: 0 - 65534.
1025 * id 65535 is reserved to indicate an extended header.
1027 * Must be called with sessions_mutex held.
1030 int _lttng_event_header_declare(struct lttng_session
*session
)
1032 return lttng_metadata_printf(session
,
1033 "struct event_header_compact {\n"
1034 " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
1037 " uint27_clock_monotonic_t timestamp;\n"
1041 " uint64_clock_monotonic_t timestamp;\n"
1046 "struct event_header_large {\n"
1047 " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
1050 " uint32_clock_monotonic_t timestamp;\n"
1054 " uint64_clock_monotonic_t timestamp;\n"
1058 lttng_alignof(uint32_t) * CHAR_BIT
,
1059 lttng_alignof(uint16_t) * CHAR_BIT
1064 * Approximation of NTP time of day to clock monotonic correlation,
1065 * taken at start of trace.
1066 * Yes, this is only an approximation. Yes, we can (and will) do better
1067 * in future versions.
1070 uint64_t measure_clock_offset(void)
1072 uint64_t offset
, monotonic
[2], realtime
;
1073 struct timespec rts
= { 0, 0 };
1074 unsigned long flags
;
1076 /* Disable interrupts to increase correlation precision. */
1077 local_irq_save(flags
);
1078 monotonic
[0] = trace_clock_read64();
1079 getnstimeofday(&rts
);
1080 monotonic
[1] = trace_clock_read64();
1081 local_irq_restore(flags
);
1083 offset
= (monotonic
[0] + monotonic
[1]) >> 1;
1084 realtime
= (uint64_t) rts
.tv_sec
* NSEC_PER_SEC
;
1085 realtime
+= rts
.tv_nsec
;
1086 offset
= realtime
- offset
;
1091 * Output metadata into this session's metadata buffers.
1092 * Must be called with sessions_mutex held.
1095 int _lttng_session_metadata_statedump(struct lttng_session
*session
)
1097 unsigned char *uuid_c
= session
->uuid
.b
;
1098 unsigned char uuid_s
[37], clock_uuid_s
[BOOT_ID_LEN
];
1099 struct lttng_channel
*chan
;
1100 struct lttng_event
*event
;
1103 if (!ACCESS_ONCE(session
->active
))
1105 if (session
->metadata_dumped
)
1108 snprintf(uuid_s
, sizeof(uuid_s
),
1109 "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
1110 uuid_c
[0], uuid_c
[1], uuid_c
[2], uuid_c
[3],
1111 uuid_c
[4], uuid_c
[5], uuid_c
[6], uuid_c
[7],
1112 uuid_c
[8], uuid_c
[9], uuid_c
[10], uuid_c
[11],
1113 uuid_c
[12], uuid_c
[13], uuid_c
[14], uuid_c
[15]);
1115 ret
= lttng_metadata_printf(session
,
1116 "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
1117 "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
1118 "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
1119 "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
1120 "typealias integer { size = %u; align = %u; signed = false; } := unsigned long;\n"
1121 "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
1122 "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
1128 " byte_order = %s;\n"
1129 " packet.header := struct {\n"
1130 " uint32_t magic;\n"
1131 " uint8_t uuid[16];\n"
1132 " uint32_t stream_id;\n"
1135 lttng_alignof(uint8_t) * CHAR_BIT
,
1136 lttng_alignof(uint16_t) * CHAR_BIT
,
1137 lttng_alignof(uint32_t) * CHAR_BIT
,
1138 lttng_alignof(uint64_t) * CHAR_BIT
,
1139 sizeof(unsigned long) * CHAR_BIT
,
1140 lttng_alignof(unsigned long) * CHAR_BIT
,
1153 ret
= lttng_metadata_printf(session
,
1155 " hostname = \"%s\";\n"
1156 " domain = \"kernel\";\n"
1157 " sysname = \"%s\";\n"
1158 " kernel_release = \"%s\";\n"
1159 " kernel_version = \"%s\";\n"
1160 " tracer_name = \"lttng-modules\";\n"
1161 " tracer_major = %d;\n"
1162 " tracer_minor = %d;\n"
1163 " tracer_patchlevel = %d;\n"
1165 current
->nsproxy
->uts_ns
->name
.nodename
,
1169 LTTNG_MODULES_MAJOR_VERSION
,
1170 LTTNG_MODULES_MINOR_VERSION
,
1171 LTTNG_MODULES_PATCHLEVEL_VERSION
1176 ret
= lttng_metadata_printf(session
,
1184 if (!trace_clock_uuid(clock_uuid_s
)) {
1185 ret
= lttng_metadata_printf(session
,
1186 " uuid = \"%s\";\n",
1193 ret
= lttng_metadata_printf(session
,
1194 " description = \"Monotonic Clock\";\n"
1195 " freq = %llu; /* Frequency, in Hz */\n"
1196 " /* clock value offset from Epoch is: offset * (1/freq) */\n"
1199 (unsigned long long) trace_clock_freq(),
1200 (unsigned long long) measure_clock_offset()
1205 ret
= lttng_metadata_printf(session
,
1206 "typealias integer {\n"
1207 " size = 27; align = 1; signed = false;\n"
1208 " map = clock.monotonic.value;\n"
1209 "} := uint27_clock_monotonic_t;\n"
1211 "typealias integer {\n"
1212 " size = 32; align = %u; signed = false;\n"
1213 " map = clock.monotonic.value;\n"
1214 "} := uint32_clock_monotonic_t;\n"
1216 "typealias integer {\n"
1217 " size = 64; align = %u; signed = false;\n"
1218 " map = clock.monotonic.value;\n"
1219 "} := uint64_clock_monotonic_t;\n\n",
1220 lttng_alignof(uint32_t) * CHAR_BIT
,
1221 lttng_alignof(uint64_t) * CHAR_BIT
1226 ret
= _lttng_stream_packet_context_declare(session
);
1230 ret
= _lttng_event_header_declare(session
);
1235 list_for_each_entry(chan
, &session
->chan
, list
) {
1236 ret
= _lttng_channel_metadata_statedump(session
, chan
);
1241 list_for_each_entry(event
, &session
->events
, list
) {
1242 ret
= _lttng_event_metadata_statedump(session
, event
->chan
, event
);
1246 session
->metadata_dumped
= 1;
1252 * lttng_transport_register - LTT transport registration
1253 * @transport: transport structure
1255 * Registers a transport which can be used as output to extract the data out of
1256 * LTTng. The module calling this registration function must ensure that no
1257 * trap-inducing code will be executed by the transport functions. E.g.
1258 * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
1259 * is made visible to the transport function. This registration acts as a
1260 * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
1261 * after its registration must it synchronize the TLBs.
1263 void lttng_transport_register(struct lttng_transport
*transport
)
1266 * Make sure no page fault can be triggered by the module about to be
1267 * registered. We deal with this here so we don't have to call
1268 * vmalloc_sync_all() in each module's init.
1270 wrapper_vmalloc_sync_all();
1272 mutex_lock(&sessions_mutex
);
1273 list_add_tail(&transport
->node
, <tng_transport_list
);
1274 mutex_unlock(&sessions_mutex
);
1276 EXPORT_SYMBOL_GPL(lttng_transport_register
);
1279 * lttng_transport_unregister - LTT transport unregistration
1280 * @transport: transport structure
1282 void lttng_transport_unregister(struct lttng_transport
*transport
)
1284 mutex_lock(&sessions_mutex
);
1285 list_del(&transport
->node
);
1286 mutex_unlock(&sessions_mutex
);
1288 EXPORT_SYMBOL_GPL(lttng_transport_unregister
);
1290 static int __init
lttng_events_init(void)
1294 ret
= wrapper_lttng_fixup_sig(THIS_MODULE
);
1297 ret
= wrapper_get_pfnblock_flags_mask_init();
1300 ret
= lttng_tracepoint_init();
1303 event_cache
= KMEM_CACHE(lttng_event
, 0);
1308 ret
= lttng_abi_init();
1311 ret
= lttng_logger_init();
1319 kmem_cache_destroy(event_cache
);
1321 lttng_tracepoint_exit();
1325 module_init(lttng_events_init
);
1327 static void __exit
lttng_events_exit(void)
1329 struct lttng_session
*session
, *tmpsession
;
1331 lttng_logger_exit();
1333 list_for_each_entry_safe(session
, tmpsession
, &sessions
, list
)
1334 lttng_session_destroy(session
);
1335 kmem_cache_destroy(event_cache
);
1336 lttng_tracepoint_exit();
1339 module_exit(lttng_events_exit
);
1341 MODULE_LICENSE("GPL and additional rights");
1342 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
1343 MODULE_DESCRIPTION("LTTng Events");
1344 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION
) "."
1345 __stringify(LTTNG_MODULES_MINOR_VERSION
) "."
1346 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION
)
1347 LTTNG_MODULES_EXTRAVERSION
);