4 * Copyright 2010-2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * Mimic system calls for:
9 * - session creation, returns an object descriptor or failure.
10 * - channel creation, returns an object descriptor or failure.
11 * - Operates on a session object descriptor
12 * - Takes all channel options as parameters.
13 * - stream get, returns an object descriptor or failure.
14 * - Operates on a channel object descriptor.
15 * - stream notifier get, returns an object descriptor or failure.
16 * - Operates on a channel object descriptor.
17 * - event creation, returns an object descriptor or failure.
18 * - Operates on a channel object descriptor
19 * - Takes an event name as parameter
20 * - Takes an instrumentation source as parameter
21 * - e.g. tracepoints, dynamic_probes...
22 * - Takes instrumentation source specific arguments.
24 * Dual LGPL v2.1/GPL v2 license.
27 #include <lttng/ust-abi.h>
28 #include <urcu/compiler.h>
29 #include <urcu/list.h>
30 #include <lttng/ust-events.h>
31 #include <lttng/usterr-signal-safe.h>
32 #include "lttng/core.h"
33 #include <lttng/ust-version.h>
34 #include "ltt-tracer.h"
35 #include "tracepoint-internal.h"
37 struct ltt_tracepoint_list
{
38 struct tracepoint_iter iter
;
42 static int lttng_ust_abi_close_in_progress
;
45 int lttng_abi_tracepoint_list(void);
48 * Object descriptor table. Should be protected from concurrent access
52 struct lttng_ust_obj
{
56 const struct lttng_ust_objd_ops
*ops
;
59 int freelist_next
; /* offset freelist. end is -1. */
63 struct lttng_ust_objd_table
{
64 struct lttng_ust_obj
*array
;
65 unsigned int len
, allocated_len
;
66 int freelist_head
; /* offset freelist head. end is -1 */
69 static struct lttng_ust_objd_table objd_table
= {
74 int objd_alloc(void *private_data
, const struct lttng_ust_objd_ops
*ops
)
76 struct lttng_ust_obj
*obj
;
78 if (objd_table
.freelist_head
!= -1) {
79 obj
= &objd_table
.array
[objd_table
.freelist_head
];
80 objd_table
.freelist_head
= obj
->u
.freelist_next
;
84 if (objd_table
.len
>= objd_table
.allocated_len
) {
85 unsigned int new_allocated_len
, old_allocated_len
;
86 struct lttng_ust_obj
*new_table
, *old_table
;
88 old_allocated_len
= objd_table
.allocated_len
;
89 old_table
= objd_table
.array
;
90 if (!old_allocated_len
)
91 new_allocated_len
= 1;
93 new_allocated_len
= old_allocated_len
<< 1;
94 new_table
= zmalloc(sizeof(struct lttng_ust_obj
) * new_allocated_len
);
97 memcpy(new_table
, old_table
,
98 sizeof(struct lttng_ust_obj
) * old_allocated_len
);
100 objd_table
.array
= new_table
;
101 objd_table
.allocated_len
= new_allocated_len
;
103 obj
= &objd_table
.array
[objd_table
.len
];
106 obj
->u
.s
.private_data
= private_data
;
108 obj
->u
.s
.f_count
= 2; /* count == 1 : object is allocated */
109 /* count == 2 : allocated + hold ref */
110 return obj
- objd_table
.array
;
114 struct lttng_ust_obj
*_objd_get(int id
)
116 if (id
>= objd_table
.len
)
118 if (!objd_table
.array
[id
].u
.s
.f_count
)
120 return &objd_table
.array
[id
];
124 void *objd_private(int id
)
126 struct lttng_ust_obj
*obj
= _objd_get(id
);
128 return obj
->u
.s
.private_data
;
132 void objd_set_private(int id
, void *private_data
)
134 struct lttng_ust_obj
*obj
= _objd_get(id
);
136 obj
->u
.s
.private_data
= private_data
;
139 const struct lttng_ust_objd_ops
*objd_ops(int id
)
141 struct lttng_ust_obj
*obj
= _objd_get(id
);
149 void objd_free(int id
)
151 struct lttng_ust_obj
*obj
= _objd_get(id
);
154 obj
->u
.freelist_next
= objd_table
.freelist_head
;
155 objd_table
.freelist_head
= obj
- objd_table
.array
;
156 assert(obj
->u
.s
.f_count
== 1);
157 obj
->u
.s
.f_count
= 0; /* deallocated */
161 void objd_ref(int id
)
163 struct lttng_ust_obj
*obj
= _objd_get(id
);
167 int lttng_ust_objd_unref(int id
)
169 struct lttng_ust_obj
*obj
= _objd_get(id
);
173 if (obj
->u
.s
.f_count
== 1) {
174 ERR("Reference counting error\n");
177 if ((--obj
->u
.s
.f_count
) == 1) {
178 const struct lttng_ust_objd_ops
*ops
= objd_ops(id
);
188 void objd_table_destroy(void)
192 for (i
= 0; i
< objd_table
.allocated_len
; i
++)
193 (void) lttng_ust_objd_unref(i
);
194 free(objd_table
.array
);
195 objd_table
.array
= NULL
;
197 objd_table
.allocated_len
= 0;
198 objd_table
.freelist_head
= -1;
202 * This is LTTng's own personal way to create an ABI for sessiond.
203 * We send commands over a socket.
206 static const struct lttng_ust_objd_ops lttng_ops
;
207 static const struct lttng_ust_objd_ops lttng_session_ops
;
208 static const struct lttng_ust_objd_ops lttng_channel_ops
;
209 static const struct lttng_ust_objd_ops lttng_metadata_ops
;
210 static const struct lttng_ust_objd_ops lttng_event_ops
;
211 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops
;
212 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops
;
219 int lttng_abi_create_root_handle(void)
223 root_handle
= objd_alloc(NULL
, <tng_ops
);
228 int lttng_abi_create_session(void)
230 struct ltt_session
*session
;
231 int session_objd
, ret
;
233 session
= ltt_session_create();
236 session_objd
= objd_alloc(session
, <tng_session_ops
);
237 if (session_objd
< 0) {
241 session
->objd
= session_objd
;
245 ltt_session_destroy(session
);
250 long lttng_abi_tracer_version(int objd
,
251 struct lttng_ust_tracer_version
*v
)
253 v
->major
= LTTNG_UST_MAJOR_VERSION
;
254 v
->minor
= LTTNG_UST_MINOR_VERSION
;
255 v
->patchlevel
= LTTNG_UST_PATCHLEVEL_VERSION
;
260 long lttng_abi_add_context(int objd
,
261 struct lttng_ust_context
*context_param
,
262 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
264 if (session
->been_active
)
267 switch (context_param
->ctx
) {
268 case LTTNG_UST_CONTEXT_PTHREAD_ID
:
269 return lttng_add_pthread_id_to_ctx(ctx
);
270 case LTTNG_UST_CONTEXT_VTID
:
271 return lttng_add_vtid_to_ctx(ctx
);
272 case LTTNG_UST_CONTEXT_VPID
:
273 return lttng_add_vpid_to_ctx(ctx
);
274 case LTTNG_UST_CONTEXT_PROCNAME
:
275 return lttng_add_procname_to_ctx(ctx
);
282 * lttng_cmd - lttng control through socket commands
284 * @objd: the object descriptor
288 * This descriptor implements lttng commands:
290 * Returns a LTTng trace session object descriptor
291 * LTTNG_UST_TRACER_VERSION
292 * Returns the LTTng kernel tracer version
293 * LTTNG_UST_TRACEPOINT_LIST
294 * Returns a file descriptor listing available tracepoints
295 * LTTNG_UST_WAIT_QUIESCENT
296 * Returns after all previously running probes have completed
298 * The returned session will be deleted when its file descriptor is closed.
301 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
304 case LTTNG_UST_SESSION
:
305 return lttng_abi_create_session();
306 case LTTNG_UST_TRACER_VERSION
:
307 return lttng_abi_tracer_version(objd
,
308 (struct lttng_ust_tracer_version
*) arg
);
309 case LTTNG_UST_TRACEPOINT_LIST
:
310 return lttng_abi_tracepoint_list();
311 case LTTNG_UST_WAIT_QUIESCENT
:
319 static const struct lttng_ust_objd_ops lttng_ops
= {
324 * We tolerate no failure in this function (if one happens, we print a dmesg
325 * error, but cannot return any error, because the channel information is
329 void lttng_metadata_create_events(int channel_objd
)
331 struct ltt_channel
*channel
= objd_private(channel_objd
);
332 static struct lttng_ust_event metadata_params
= {
333 .instrumentation
= LTTNG_UST_TRACEPOINT
,
334 .name
= "lttng_ust:metadata",
336 struct ltt_event
*event
;
339 * We tolerate no failure path after event creation. It will stay
340 * invariant for the rest of the session.
342 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
350 return; /* not allowed to return error */
353 int lttng_abi_create_channel(int session_objd
,
354 struct lttng_ust_channel
*chan_param
,
355 enum channel_type channel_type
)
357 struct ltt_session
*session
= objd_private(session_objd
);
358 const struct lttng_ust_objd_ops
*ops
;
359 const char *transport_name
;
360 struct ltt_channel
*chan
;
363 struct ltt_channel chan_priv_init
;
365 switch (channel_type
) {
366 case PER_CPU_CHANNEL
:
367 if (chan_param
->output
== LTTNG_UST_MMAP
) {
368 transport_name
= chan_param
->overwrite
?
369 "relay-overwrite-mmap" : "relay-discard-mmap";
373 ops
= <tng_channel_ops
;
375 case METADATA_CHANNEL
:
376 if (chan_param
->output
== LTTNG_UST_MMAP
)
377 transport_name
= "relay-metadata-mmap";
380 ops
= <tng_metadata_ops
;
383 transport_name
= "<unknown>";
386 chan_objd
= objd_alloc(NULL
, ops
);
391 memset(&chan_priv_init
, 0, sizeof(chan_priv_init
));
392 /* Copy of session UUID for consumer (availability through shm) */
393 memcpy(chan_priv_init
.uuid
, session
->uuid
, sizeof(session
->uuid
));
396 * We tolerate no failure path after channel creation. It will stay
397 * invariant for the rest of the session.
399 chan
= ltt_channel_create(session
, transport_name
, NULL
,
400 chan_param
->subbuf_size
,
401 chan_param
->num_subbuf
,
402 chan_param
->switch_timer_interval
,
403 chan_param
->read_timer_interval
,
405 &chan_param
->wait_fd
,
406 &chan_param
->memory_map_size
,
412 objd_set_private(chan_objd
, chan
);
413 chan
->objd
= chan_objd
;
414 if (channel_type
== METADATA_CHANNEL
) {
415 session
->metadata
= chan
;
416 lttng_metadata_create_events(chan_objd
);
418 /* The channel created holds a reference on the session */
419 objd_ref(session_objd
);
427 err
= lttng_ust_objd_unref(chan_objd
);
435 * lttng_session_cmd - lttng session object command
441 * This descriptor implements lttng commands:
443 * Returns a LTTng channel object descriptor
445 * Enables tracing for a session (weak enable)
447 * Disables tracing for a session (strong disable)
449 * Returns a LTTng metadata object descriptor
451 * The returned channel will be deleted when its file descriptor is closed.
454 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
456 struct ltt_session
*session
= objd_private(objd
);
459 case LTTNG_UST_CHANNEL
:
460 return lttng_abi_create_channel(objd
,
461 (struct lttng_ust_channel
*) arg
,
463 case LTTNG_UST_SESSION_START
:
464 case LTTNG_UST_ENABLE
:
465 return ltt_session_enable(session
);
466 case LTTNG_UST_SESSION_STOP
:
467 case LTTNG_UST_DISABLE
:
468 return ltt_session_disable(session
);
469 case LTTNG_UST_METADATA
:
470 return lttng_abi_create_channel(objd
,
471 (struct lttng_ust_channel
*) arg
,
479 * Called when the last file reference is dropped.
481 * Big fat note: channels and events are invariant for the whole session after
482 * their creation. So this session destruction also destroys all channel and
483 * event structures specific to this session (they are not destroyed when their
484 * individual file is released).
487 int lttng_release_session(int objd
)
489 struct ltt_session
*session
= objd_private(objd
);
492 ltt_session_destroy(session
);
499 static const struct lttng_ust_objd_ops lttng_session_ops
= {
500 .release
= lttng_release_session
,
501 .cmd
= lttng_session_cmd
,
505 * beware: we don't keep the mutex over the send, but we must walk the
506 * whole list each time we are called again. So sending one tracepoint
507 * at a time means this is O(n^2). TODO: do as in the kernel and send
508 * multiple tracepoints for each call to amortize this cost.
511 void ltt_tracepoint_list_get(struct ltt_tracepoint_list
*list
,
515 if (!list
->got_first
) {
516 tracepoint_iter_start(&list
->iter
);
520 tracepoint_iter_next(&list
->iter
);
522 if (!list
->iter
.tracepoint
) {
523 tp_list_entry
[0] = '\0'; /* end of list */
525 if (!strcmp((*list
->iter
.tracepoint
)->name
,
526 "lttng_ust:metadata"))
528 memcpy(tp_list_entry
, (*list
->iter
.tracepoint
)->name
,
529 LTTNG_UST_SYM_NAME_LEN
);
534 long lttng_tracepoint_list_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
536 struct ltt_tracepoint_list
*list
= objd_private(objd
);
537 char *str
= (char *) arg
;
540 case LTTNG_UST_TRACEPOINT_LIST_GET
:
541 ltt_tracepoint_list_get(list
, str
);
551 int lttng_abi_tracepoint_list(void)
554 struct ltt_tracepoint_list
*list
;
556 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
561 list
= zmalloc(sizeof(*list
));
566 objd_set_private(list_objd
, list
);
574 err
= lttng_ust_objd_unref(list_objd
);
582 int lttng_release_tracepoint_list(int objd
)
584 struct ltt_tracepoint_list
*list
= objd_private(objd
);
587 tracepoint_iter_stop(&list
->iter
);
595 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops
= {
596 .release
= lttng_release_tracepoint_list
,
597 .cmd
= lttng_tracepoint_list_cmd
,
600 struct stream_priv_data
{
601 struct lttng_ust_lib_ring_buffer
*buf
;
602 struct ltt_channel
*ltt_chan
;
606 int lttng_abi_open_stream(int channel_objd
, struct lttng_ust_stream
*info
)
608 struct ltt_channel
*channel
= objd_private(channel_objd
);
609 struct lttng_ust_lib_ring_buffer
*buf
;
610 struct stream_priv_data
*priv
;
611 int stream_objd
, ret
;
613 buf
= channel
->ops
->buffer_read_open(channel
->chan
, channel
->handle
,
614 &info
->shm_fd
, &info
->wait_fd
, &info
->memory_map_size
);
618 priv
= zmalloc(sizeof(*priv
));
624 priv
->ltt_chan
= channel
;
625 stream_objd
= objd_alloc(priv
, &lib_ring_buffer_objd_ops
);
626 if (stream_objd
< 0) {
630 /* Hold a reference on the channel object descriptor */
631 objd_ref(channel_objd
);
637 channel
->ops
->buffer_read_close(buf
, channel
->handle
);
642 int lttng_abi_create_event(int channel_objd
,
643 struct lttng_ust_event
*event_param
)
645 struct ltt_channel
*channel
= objd_private(channel_objd
);
646 struct ltt_event
*event
;
649 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
650 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
651 if (event_objd
< 0) {
656 * We tolerate no failure path after event creation. It will stay
657 * invariant for the rest of the session.
659 event
= ltt_event_create(channel
, event_param
, NULL
);
664 objd_set_private(event_objd
, event
);
665 /* The event holds a reference on the channel */
666 objd_ref(channel_objd
);
673 err
= lttng_ust_objd_unref(event_objd
);
681 * lttng_channel_cmd - lttng control through object descriptors
683 * @objd: the object descriptor
687 * This object descriptor implements lttng commands:
689 * Returns an event stream object descriptor or failure.
690 * (typically, one event stream records events from one CPU)
692 * Returns an event object descriptor or failure.
694 * Prepend a context field to each event in the channel
696 * Enable recording for events in this channel (weak enable)
698 * Disable recording for events in this channel (strong disable)
700 * Channel and event file descriptors also hold a reference on the session.
703 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
705 struct ltt_channel
*channel
= objd_private(objd
);
708 case LTTNG_UST_STREAM
:
710 struct lttng_ust_stream
*stream
;
712 stream
= (struct lttng_ust_stream
*) arg
;
713 /* stream used as output */
714 return lttng_abi_open_stream(objd
, stream
);
716 case LTTNG_UST_EVENT
:
717 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
718 case LTTNG_UST_CONTEXT
:
719 return lttng_abi_add_context(objd
,
720 (struct lttng_ust_context
*) arg
,
721 &channel
->ctx
, channel
->session
);
722 case LTTNG_UST_ENABLE
:
723 return ltt_channel_enable(channel
);
724 case LTTNG_UST_DISABLE
:
725 return ltt_channel_disable(channel
);
726 case LTTNG_UST_FLUSH_BUFFER
:
727 return channel
->ops
->flush_buffer(channel
->chan
, channel
->handle
);
734 * lttng_metadata_cmd - lttng control through object descriptors
736 * @objd: the object descriptor
740 * This object descriptor implements lttng commands:
742 * Returns an event stream file descriptor or failure.
744 * Channel and event file descriptors also hold a reference on the session.
747 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
749 struct ltt_channel
*channel
= objd_private(objd
);
752 case LTTNG_UST_STREAM
:
754 struct lttng_ust_stream
*stream
;
756 stream
= (struct lttng_ust_stream
*) arg
;
757 /* stream used as output */
758 return lttng_abi_open_stream(objd
, stream
);
760 case LTTNG_UST_FLUSH_BUFFER
:
761 return channel
->ops
->flush_buffer(channel
->chan
, channel
->handle
);
769 * lttng_channel_poll - lttng stream addition/removal monitoring
774 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
776 struct ltt_channel
*channel
= file
->private_data
;
777 unsigned int mask
= 0;
779 if (file
->f_mode
& FMODE_READ
) {
780 poll_wait_set_exclusive(wait
);
781 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
784 if (channel
->ops
->is_disabled(channel
->chan
))
786 if (channel
->ops
->is_finalized(channel
->chan
))
788 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
789 return POLLIN
| POLLRDNORM
;
798 int lttng_channel_release(int objd
)
800 struct ltt_channel
*channel
= objd_private(objd
);
803 return lttng_ust_objd_unref(channel
->session
->objd
);
807 static const struct lttng_ust_objd_ops lttng_channel_ops
= {
808 .release
= lttng_channel_release
,
809 //.poll = lttng_channel_poll,
810 .cmd
= lttng_channel_cmd
,
813 static const struct lttng_ust_objd_ops lttng_metadata_ops
= {
814 .release
= lttng_channel_release
,
815 .cmd
= lttng_metadata_cmd
,
819 * lttng_rb_cmd - lttng ring buffer control through object descriptors
821 * @objd: the object descriptor
825 * This object descriptor implements lttng commands:
826 * (None for now. Access is done directly though shm.)
829 long lttng_rb_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
838 int lttng_rb_release(int objd
)
840 struct stream_priv_data
*priv
= objd_private(objd
);
841 struct lttng_ust_lib_ring_buffer
*buf
;
842 struct ltt_channel
*channel
;
846 channel
= priv
->ltt_chan
;
849 * If we are at ABI exit, we don't want to close the
850 * buffer opened for read: it is being shared between
851 * the parent and child (right after fork), and we don't
852 * want the child to close it for the parent. For a real
853 * exit, we don't care about marking it as closed, as
854 * the consumer daemon (if there is one) will do fine
855 * even if we don't mark it as "closed" for reading on
857 * We only mark it as closed if it is being explicitely
858 * released by the session daemon with an explicit
861 if (!lttng_ust_abi_close_in_progress
)
862 channel
->ops
->buffer_read_close(buf
, channel
->handle
);
864 return lttng_ust_objd_unref(channel
->objd
);
869 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops
= {
870 .release
= lttng_rb_release
,
875 * lttng_event_cmd - lttng control through object descriptors
877 * @objd: the object descriptor
881 * This object descriptor implements lttng commands:
883 * Prepend a context field to each record of this event
885 * Enable recording for this event (weak enable)
887 * Disable recording for this event (strong disable)
890 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
892 struct ltt_event
*event
= objd_private(objd
);
895 case LTTNG_UST_CONTEXT
:
896 return lttng_abi_add_context(objd
,
897 (struct lttng_ust_context
*) arg
,
898 &event
->ctx
, event
->chan
->session
);
899 case LTTNG_UST_ENABLE
:
900 return ltt_event_enable(event
);
901 case LTTNG_UST_DISABLE
:
902 return ltt_event_disable(event
);
909 int lttng_event_release(int objd
)
911 struct ltt_event
*event
= objd_private(objd
);
914 return lttng_ust_objd_unref(event
->chan
->objd
);
918 /* TODO: filter control ioctl */
919 static const struct lttng_ust_objd_ops lttng_event_ops
= {
920 .release
= lttng_event_release
,
921 .cmd
= lttng_event_cmd
,
924 void lttng_ust_abi_exit(void)
926 lttng_ust_abi_close_in_progress
= 1;
927 objd_table_destroy();
928 lttng_ust_abi_close_in_progress
= 0;