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/ust-version.h>
32 #include <usterr-signal-safe.h>
34 #include "ltt-tracer.h"
35 #include "tracepoint-internal.h"
37 static int lttng_ust_abi_close_in_progress
;
40 int lttng_abi_tracepoint_list(void);
43 * Object descriptor table. Should be protected from concurrent access
47 struct lttng_ust_obj
{
51 const struct lttng_ust_objd_ops
*ops
;
54 int freelist_next
; /* offset freelist. end is -1. */
58 struct lttng_ust_objd_table
{
59 struct lttng_ust_obj
*array
;
60 unsigned int len
, allocated_len
;
61 int freelist_head
; /* offset freelist head. end is -1 */
64 static struct lttng_ust_objd_table objd_table
= {
69 int objd_alloc(void *private_data
, const struct lttng_ust_objd_ops
*ops
)
71 struct lttng_ust_obj
*obj
;
73 if (objd_table
.freelist_head
!= -1) {
74 obj
= &objd_table
.array
[objd_table
.freelist_head
];
75 objd_table
.freelist_head
= obj
->u
.freelist_next
;
79 if (objd_table
.len
>= objd_table
.allocated_len
) {
80 unsigned int new_allocated_len
, old_allocated_len
;
81 struct lttng_ust_obj
*new_table
, *old_table
;
83 old_allocated_len
= objd_table
.allocated_len
;
84 old_table
= objd_table
.array
;
85 if (!old_allocated_len
)
86 new_allocated_len
= 1;
88 new_allocated_len
= old_allocated_len
<< 1;
89 new_table
= zmalloc(sizeof(struct lttng_ust_obj
) * new_allocated_len
);
92 memcpy(new_table
, old_table
,
93 sizeof(struct lttng_ust_obj
) * old_allocated_len
);
95 objd_table
.array
= new_table
;
96 objd_table
.allocated_len
= new_allocated_len
;
98 obj
= &objd_table
.array
[objd_table
.len
];
101 obj
->u
.s
.private_data
= private_data
;
103 obj
->u
.s
.f_count
= 2; /* count == 1 : object is allocated */
104 /* count == 2 : allocated + hold ref */
105 return obj
- objd_table
.array
;
109 struct lttng_ust_obj
*_objd_get(int id
)
111 if (id
>= objd_table
.len
)
113 if (!objd_table
.array
[id
].u
.s
.f_count
)
115 return &objd_table
.array
[id
];
119 void *objd_private(int id
)
121 struct lttng_ust_obj
*obj
= _objd_get(id
);
123 return obj
->u
.s
.private_data
;
127 void objd_set_private(int id
, void *private_data
)
129 struct lttng_ust_obj
*obj
= _objd_get(id
);
131 obj
->u
.s
.private_data
= private_data
;
134 const struct lttng_ust_objd_ops
*objd_ops(int id
)
136 struct lttng_ust_obj
*obj
= _objd_get(id
);
144 void objd_free(int id
)
146 struct lttng_ust_obj
*obj
= _objd_get(id
);
149 obj
->u
.freelist_next
= objd_table
.freelist_head
;
150 objd_table
.freelist_head
= obj
- objd_table
.array
;
151 assert(obj
->u
.s
.f_count
== 1);
152 obj
->u
.s
.f_count
= 0; /* deallocated */
156 void objd_ref(int id
)
158 struct lttng_ust_obj
*obj
= _objd_get(id
);
162 int lttng_ust_objd_unref(int id
)
164 struct lttng_ust_obj
*obj
= _objd_get(id
);
168 if (obj
->u
.s
.f_count
== 1) {
169 ERR("Reference counting error\n");
172 if ((--obj
->u
.s
.f_count
) == 1) {
173 const struct lttng_ust_objd_ops
*ops
= objd_ops(id
);
183 void objd_table_destroy(void)
187 for (i
= 0; i
< objd_table
.allocated_len
; i
++)
188 (void) lttng_ust_objd_unref(i
);
189 free(objd_table
.array
);
190 objd_table
.array
= NULL
;
192 objd_table
.allocated_len
= 0;
193 objd_table
.freelist_head
= -1;
197 * This is LTTng's own personal way to create an ABI for sessiond.
198 * We send commands over a socket.
201 static const struct lttng_ust_objd_ops lttng_ops
;
202 static const struct lttng_ust_objd_ops lttng_session_ops
;
203 static const struct lttng_ust_objd_ops lttng_channel_ops
;
204 static const struct lttng_ust_objd_ops lttng_metadata_ops
;
205 static const struct lttng_ust_objd_ops lttng_event_ops
;
206 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops
;
207 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops
;
214 int lttng_abi_create_root_handle(void)
218 root_handle
= objd_alloc(NULL
, <tng_ops
);
223 int lttng_abi_create_session(void)
225 struct ltt_session
*session
;
226 int session_objd
, ret
;
228 session
= ltt_session_create();
231 session_objd
= objd_alloc(session
, <tng_session_ops
);
232 if (session_objd
< 0) {
236 session
->objd
= session_objd
;
240 ltt_session_destroy(session
);
245 long lttng_abi_tracer_version(int objd
,
246 struct lttng_ust_tracer_version
*v
)
248 v
->major
= LTTNG_UST_MAJOR_VERSION
;
249 v
->minor
= LTTNG_UST_MINOR_VERSION
;
250 v
->patchlevel
= LTTNG_UST_PATCHLEVEL_VERSION
;
255 long lttng_abi_add_context(int objd
,
256 struct lttng_ust_context
*context_param
,
257 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
259 if (session
->been_active
)
262 switch (context_param
->ctx
) {
263 case LTTNG_UST_CONTEXT_PTHREAD_ID
:
264 return lttng_add_pthread_id_to_ctx(ctx
);
265 case LTTNG_UST_CONTEXT_VTID
:
266 return lttng_add_vtid_to_ctx(ctx
);
267 case LTTNG_UST_CONTEXT_VPID
:
268 return lttng_add_vpid_to_ctx(ctx
);
269 case LTTNG_UST_CONTEXT_PROCNAME
:
270 return lttng_add_procname_to_ctx(ctx
);
277 * lttng_cmd - lttng control through socket commands
279 * @objd: the object descriptor
283 * This descriptor implements lttng commands:
285 * Returns a LTTng trace session object descriptor
286 * LTTNG_UST_TRACER_VERSION
287 * Returns the LTTng kernel tracer version
288 * LTTNG_UST_TRACEPOINT_LIST
289 * Returns a file descriptor listing available tracepoints
290 * LTTNG_UST_WAIT_QUIESCENT
291 * Returns after all previously running probes have completed
293 * The returned session will be deleted when its file descriptor is closed.
296 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
299 case LTTNG_UST_SESSION
:
300 return lttng_abi_create_session();
301 case LTTNG_UST_TRACER_VERSION
:
302 return lttng_abi_tracer_version(objd
,
303 (struct lttng_ust_tracer_version
*) arg
);
304 case LTTNG_UST_TRACEPOINT_LIST
:
305 return lttng_abi_tracepoint_list();
306 case LTTNG_UST_WAIT_QUIESCENT
:
314 static const struct lttng_ust_objd_ops lttng_ops
= {
319 * We tolerate no failure in this function (if one happens, we print a dmesg
320 * error, but cannot return any error, because the channel information is
324 void lttng_metadata_create_events(int channel_objd
)
326 struct ltt_channel
*channel
= objd_private(channel_objd
);
327 static struct lttng_ust_event metadata_params
= {
328 .instrumentation
= LTTNG_UST_TRACEPOINT
,
329 .name
= "lttng_ust:metadata",
331 struct ltt_event
*event
;
335 * We tolerate no failure path after event creation. It will stay
336 * invariant for the rest of the session.
338 ret
= ltt_event_create(channel
, &metadata_params
, NULL
, &event
);
346 return; /* not allowed to return error */
349 int lttng_abi_create_channel(int session_objd
,
350 struct lttng_ust_channel
*chan_param
,
351 enum channel_type channel_type
)
353 struct ltt_session
*session
= objd_private(session_objd
);
354 const struct lttng_ust_objd_ops
*ops
;
355 const char *transport_name
;
356 struct ltt_channel
*chan
;
359 struct ltt_channel chan_priv_init
;
361 switch (channel_type
) {
362 case PER_CPU_CHANNEL
:
363 if (chan_param
->output
== LTTNG_UST_MMAP
) {
364 transport_name
= chan_param
->overwrite
?
365 "relay-overwrite-mmap" : "relay-discard-mmap";
369 ops
= <tng_channel_ops
;
371 case METADATA_CHANNEL
:
372 if (chan_param
->output
== LTTNG_UST_MMAP
)
373 transport_name
= "relay-metadata-mmap";
376 ops
= <tng_metadata_ops
;
379 transport_name
= "<unknown>";
382 chan_objd
= objd_alloc(NULL
, ops
);
387 memset(&chan_priv_init
, 0, sizeof(chan_priv_init
));
388 /* Copy of session UUID for consumer (availability through shm) */
389 memcpy(chan_priv_init
.uuid
, session
->uuid
, sizeof(session
->uuid
));
392 * We tolerate no failure path after channel creation. It will stay
393 * invariant for the rest of the session.
395 chan
= ltt_channel_create(session
, transport_name
, NULL
,
396 chan_param
->subbuf_size
,
397 chan_param
->num_subbuf
,
398 chan_param
->switch_timer_interval
,
399 chan_param
->read_timer_interval
,
401 &chan_param
->wait_fd
,
402 &chan_param
->memory_map_size
,
408 objd_set_private(chan_objd
, chan
);
409 chan
->objd
= chan_objd
;
410 if (channel_type
== METADATA_CHANNEL
) {
411 session
->metadata
= chan
;
412 lttng_metadata_create_events(chan_objd
);
414 /* The channel created holds a reference on the session */
415 objd_ref(session_objd
);
423 err
= lttng_ust_objd_unref(chan_objd
);
431 * lttng_session_cmd - lttng session object command
437 * This descriptor implements lttng commands:
439 * Returns a LTTng channel object descriptor
441 * Enables tracing for a session (weak enable)
443 * Disables tracing for a session (strong disable)
445 * Returns a LTTng metadata object descriptor
447 * The returned channel will be deleted when its file descriptor is closed.
450 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
452 struct ltt_session
*session
= objd_private(objd
);
455 case LTTNG_UST_CHANNEL
:
456 return lttng_abi_create_channel(objd
,
457 (struct lttng_ust_channel
*) arg
,
459 case LTTNG_UST_SESSION_START
:
460 case LTTNG_UST_ENABLE
:
461 return ltt_session_enable(session
);
462 case LTTNG_UST_SESSION_STOP
:
463 case LTTNG_UST_DISABLE
:
464 return ltt_session_disable(session
);
465 case LTTNG_UST_METADATA
:
466 return lttng_abi_create_channel(objd
,
467 (struct lttng_ust_channel
*) arg
,
475 * Called when the last file reference is dropped.
477 * Big fat note: channels and events are invariant for the whole session after
478 * their creation. So this session destruction also destroys all channel and
479 * event structures specific to this session (they are not destroyed when their
480 * individual file is released).
483 int lttng_release_session(int objd
)
485 struct ltt_session
*session
= objd_private(objd
);
488 ltt_session_destroy(session
);
495 static const struct lttng_ust_objd_ops lttng_session_ops
= {
496 .release
= lttng_release_session
,
497 .cmd
= lttng_session_cmd
,
501 long lttng_tracepoint_list_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
503 struct lttng_ust_tracepoint_list
*list
= objd_private(objd
);
504 struct lttng_ust_tracepoint_iter
*tp
=
505 (struct lttng_ust_tracepoint_iter
*) arg
;
506 struct lttng_ust_tracepoint_iter
*iter
;
509 case LTTNG_UST_TRACEPOINT_LIST_GET
:
512 iter
= lttng_ust_tracepoint_list_get_iter_next(list
);
515 if (!strcmp(iter
->name
, "lttng_ust:metadata"))
517 memcpy(tp
, iter
, sizeof(*tp
));
526 int lttng_abi_tracepoint_list(void)
529 struct lttng_ust_tracepoint_list
*list
;
531 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
536 list
= zmalloc(sizeof(*list
));
541 objd_set_private(list_objd
, list
);
543 /* populate list by walking on all registered probes. */
544 ret
= ltt_probes_get_event_list(list
);
556 err
= lttng_ust_objd_unref(list_objd
);
564 int lttng_release_tracepoint_list(int objd
)
566 struct lttng_ust_tracepoint_list
*list
= objd_private(objd
);
569 ltt_probes_prune_event_list(list
);
577 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops
= {
578 .release
= lttng_release_tracepoint_list
,
579 .cmd
= lttng_tracepoint_list_cmd
,
582 struct stream_priv_data
{
583 struct lttng_ust_lib_ring_buffer
*buf
;
584 struct ltt_channel
*ltt_chan
;
588 int lttng_abi_open_stream(int channel_objd
, struct lttng_ust_stream
*info
)
590 struct ltt_channel
*channel
= objd_private(channel_objd
);
591 struct lttng_ust_lib_ring_buffer
*buf
;
592 struct stream_priv_data
*priv
;
593 int stream_objd
, ret
;
595 buf
= channel
->ops
->buffer_read_open(channel
->chan
, channel
->handle
,
596 &info
->shm_fd
, &info
->wait_fd
, &info
->memory_map_size
);
600 priv
= zmalloc(sizeof(*priv
));
606 priv
->ltt_chan
= channel
;
607 stream_objd
= objd_alloc(priv
, &lib_ring_buffer_objd_ops
);
608 if (stream_objd
< 0) {
612 /* Hold a reference on the channel object descriptor */
613 objd_ref(channel_objd
);
619 channel
->ops
->buffer_read_close(buf
, channel
->handle
);
624 int lttng_abi_create_event(int channel_objd
,
625 struct lttng_ust_event
*event_param
)
627 struct ltt_channel
*channel
= objd_private(channel_objd
);
628 struct ltt_event
*event
;
631 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
632 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
633 if (event_objd
< 0) {
638 * We tolerate no failure path after event creation. It will stay
639 * invariant for the rest of the session.
641 ret
= ltt_event_create(channel
, event_param
, NULL
, &event
);
645 objd_set_private(event_objd
, event
);
646 /* The event holds a reference on the channel */
647 objd_ref(channel_objd
);
654 err
= lttng_ust_objd_unref(event_objd
);
662 * lttng_channel_cmd - lttng control through object descriptors
664 * @objd: the object descriptor
668 * This object descriptor implements lttng commands:
670 * Returns an event stream object descriptor or failure.
671 * (typically, one event stream records events from one CPU)
673 * Returns an event object descriptor or failure.
675 * Prepend a context field to each event in the channel
677 * Enable recording for events in this channel (weak enable)
679 * Disable recording for events in this channel (strong disable)
681 * Channel and event file descriptors also hold a reference on the session.
684 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
686 struct ltt_channel
*channel
= objd_private(objd
);
689 case LTTNG_UST_STREAM
:
691 struct lttng_ust_stream
*stream
;
693 stream
= (struct lttng_ust_stream
*) arg
;
694 /* stream used as output */
695 return lttng_abi_open_stream(objd
, stream
);
697 case LTTNG_UST_EVENT
:
698 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
699 case LTTNG_UST_CONTEXT
:
700 return lttng_abi_add_context(objd
,
701 (struct lttng_ust_context
*) arg
,
702 &channel
->ctx
, channel
->session
);
703 case LTTNG_UST_ENABLE
:
704 return ltt_channel_enable(channel
);
705 case LTTNG_UST_DISABLE
:
706 return ltt_channel_disable(channel
);
707 case LTTNG_UST_FLUSH_BUFFER
:
708 return channel
->ops
->flush_buffer(channel
->chan
, channel
->handle
);
715 * lttng_metadata_cmd - lttng control through object descriptors
717 * @objd: the object descriptor
721 * This object descriptor implements lttng commands:
723 * Returns an event stream file descriptor or failure.
725 * Channel and event file descriptors also hold a reference on the session.
728 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
730 struct ltt_channel
*channel
= objd_private(objd
);
733 case LTTNG_UST_STREAM
:
735 struct lttng_ust_stream
*stream
;
737 stream
= (struct lttng_ust_stream
*) arg
;
738 /* stream used as output */
739 return lttng_abi_open_stream(objd
, stream
);
741 case LTTNG_UST_FLUSH_BUFFER
:
742 return channel
->ops
->flush_buffer(channel
->chan
, channel
->handle
);
750 * lttng_channel_poll - lttng stream addition/removal monitoring
755 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
757 struct ltt_channel
*channel
= file
->private_data
;
758 unsigned int mask
= 0;
760 if (file
->f_mode
& FMODE_READ
) {
761 poll_wait_set_exclusive(wait
);
762 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
765 if (channel
->ops
->is_disabled(channel
->chan
))
767 if (channel
->ops
->is_finalized(channel
->chan
))
769 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
770 return POLLIN
| POLLRDNORM
;
779 int lttng_channel_release(int objd
)
781 struct ltt_channel
*channel
= objd_private(objd
);
784 return lttng_ust_objd_unref(channel
->session
->objd
);
788 static const struct lttng_ust_objd_ops lttng_channel_ops
= {
789 .release
= lttng_channel_release
,
790 //.poll = lttng_channel_poll,
791 .cmd
= lttng_channel_cmd
,
794 static const struct lttng_ust_objd_ops lttng_metadata_ops
= {
795 .release
= lttng_channel_release
,
796 .cmd
= lttng_metadata_cmd
,
800 * lttng_rb_cmd - lttng ring buffer control through object descriptors
802 * @objd: the object descriptor
806 * This object descriptor implements lttng commands:
807 * (None for now. Access is done directly though shm.)
810 long lttng_rb_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
819 int lttng_rb_release(int objd
)
821 struct stream_priv_data
*priv
= objd_private(objd
);
822 struct lttng_ust_lib_ring_buffer
*buf
;
823 struct ltt_channel
*channel
;
827 channel
= priv
->ltt_chan
;
830 * If we are at ABI exit, we don't want to close the
831 * buffer opened for read: it is being shared between
832 * the parent and child (right after fork), and we don't
833 * want the child to close it for the parent. For a real
834 * exit, we don't care about marking it as closed, as
835 * the consumer daemon (if there is one) will do fine
836 * even if we don't mark it as "closed" for reading on
838 * We only mark it as closed if it is being explicitely
839 * released by the session daemon with an explicit
842 if (!lttng_ust_abi_close_in_progress
)
843 channel
->ops
->buffer_read_close(buf
, channel
->handle
);
845 return lttng_ust_objd_unref(channel
->objd
);
850 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops
= {
851 .release
= lttng_rb_release
,
856 * lttng_event_cmd - lttng control through object descriptors
858 * @objd: the object descriptor
862 * This object descriptor implements lttng commands:
864 * Prepend a context field to each record of this event
866 * Enable recording for this event (weak enable)
868 * Disable recording for this event (strong disable)
871 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
873 struct ltt_event
*event
= objd_private(objd
);
876 case LTTNG_UST_CONTEXT
:
877 return lttng_abi_add_context(objd
,
878 (struct lttng_ust_context
*) arg
,
879 &event
->ctx
, event
->chan
->session
);
880 case LTTNG_UST_ENABLE
:
881 return ltt_event_enable(event
);
882 case LTTNG_UST_DISABLE
:
883 return ltt_event_disable(event
);
890 int lttng_event_release(int objd
)
892 struct ltt_event
*event
= objd_private(objd
);
895 return lttng_ust_objd_unref(event
->chan
->objd
);
899 /* TODO: filter control ioctl */
900 static const struct lttng_ust_objd_ops lttng_event_ops
= {
901 .release
= lttng_event_release
,
902 .cmd
= lttng_event_cmd
,
905 void lttng_ust_abi_exit(void)
907 lttng_ust_abi_close_in_progress
= 1;
908 objd_table_destroy();
909 lttng_ust_abi_close_in_progress
= 0;