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 "ltt-tracer.h"
35 static int lttng_ust_abi_close_in_progress
;
38 int lttng_abi_tracepoint_list(void);
41 * Object descriptor table. Should be protected from concurrent access
45 struct lttng_ust_obj
{
49 const struct lttng_ust_objd_ops
*ops
;
52 int freelist_next
; /* offset freelist. end is -1. */
56 struct lttng_ust_objd_table
{
57 struct lttng_ust_obj
*array
;
58 unsigned int len
, allocated_len
;
59 int freelist_head
; /* offset freelist head. end is -1 */
62 static struct lttng_ust_objd_table objd_table
= {
67 int objd_alloc(void *private_data
, const struct lttng_ust_objd_ops
*ops
)
69 struct lttng_ust_obj
*obj
;
71 if (objd_table
.freelist_head
!= -1) {
72 obj
= &objd_table
.array
[objd_table
.freelist_head
];
73 objd_table
.freelist_head
= obj
->u
.freelist_next
;
77 if (objd_table
.len
>= objd_table
.allocated_len
) {
78 unsigned int new_allocated_len
, old_allocated_len
;
79 struct lttng_ust_obj
*new_table
, *old_table
;
81 old_allocated_len
= objd_table
.allocated_len
;
82 old_table
= objd_table
.array
;
83 if (!old_allocated_len
)
84 new_allocated_len
= 1;
86 new_allocated_len
= old_allocated_len
<< 1;
87 new_table
= zmalloc(sizeof(struct lttng_ust_obj
) * new_allocated_len
);
90 memcpy(new_table
, old_table
,
91 sizeof(struct lttng_ust_obj
) * old_allocated_len
);
93 objd_table
.array
= new_table
;
94 objd_table
.allocated_len
= new_allocated_len
;
96 obj
= &objd_table
.array
[objd_table
.len
];
99 obj
->u
.s
.private_data
= private_data
;
101 obj
->u
.s
.f_count
= 2; /* count == 1 : object is allocated */
102 /* count == 2 : allocated + hold ref */
103 return obj
- objd_table
.array
;
107 struct lttng_ust_obj
*_objd_get(int id
)
109 if (id
>= objd_table
.len
)
111 if (!objd_table
.array
[id
].u
.s
.f_count
)
113 return &objd_table
.array
[id
];
117 void *objd_private(int id
)
119 struct lttng_ust_obj
*obj
= _objd_get(id
);
121 return obj
->u
.s
.private_data
;
125 void objd_set_private(int id
, void *private_data
)
127 struct lttng_ust_obj
*obj
= _objd_get(id
);
129 obj
->u
.s
.private_data
= private_data
;
132 const struct lttng_ust_objd_ops
*objd_ops(int id
)
134 struct lttng_ust_obj
*obj
= _objd_get(id
);
142 void objd_free(int id
)
144 struct lttng_ust_obj
*obj
= _objd_get(id
);
147 obj
->u
.freelist_next
= objd_table
.freelist_head
;
148 objd_table
.freelist_head
= obj
- objd_table
.array
;
149 assert(obj
->u
.s
.f_count
== 1);
150 obj
->u
.s
.f_count
= 0; /* deallocated */
154 void objd_ref(int id
)
156 struct lttng_ust_obj
*obj
= _objd_get(id
);
160 int lttng_ust_objd_unref(int id
)
162 struct lttng_ust_obj
*obj
= _objd_get(id
);
166 if (obj
->u
.s
.f_count
== 1) {
167 ERR("Reference counting error\n");
170 if ((--obj
->u
.s
.f_count
) == 1) {
171 const struct lttng_ust_objd_ops
*ops
= objd_ops(id
);
181 void objd_table_destroy(void)
185 for (i
= 0; i
< objd_table
.allocated_len
; i
++)
186 (void) lttng_ust_objd_unref(i
);
187 free(objd_table
.array
);
188 objd_table
.array
= NULL
;
190 objd_table
.allocated_len
= 0;
191 objd_table
.freelist_head
= -1;
195 * This is LTTng's own personal way to create an ABI for sessiond.
196 * We send commands over a socket.
199 static const struct lttng_ust_objd_ops lttng_ops
;
200 static const struct lttng_ust_objd_ops lttng_session_ops
;
201 static const struct lttng_ust_objd_ops lttng_channel_ops
;
202 static const struct lttng_ust_objd_ops lttng_metadata_ops
;
203 static const struct lttng_ust_objd_ops lttng_event_ops
;
204 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops
;
205 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops
;
212 int lttng_abi_create_root_handle(void)
216 root_handle
= objd_alloc(NULL
, <tng_ops
);
221 int lttng_abi_create_session(void)
223 struct ltt_session
*session
;
224 int session_objd
, ret
;
226 session
= ltt_session_create();
229 session_objd
= objd_alloc(session
, <tng_session_ops
);
230 if (session_objd
< 0) {
234 session
->objd
= session_objd
;
238 ltt_session_destroy(session
);
243 long lttng_abi_tracer_version(int objd
,
244 struct lttng_ust_tracer_version
*v
)
246 v
->version
= LTTNG_UST_VERSION
;
247 v
->patchlevel
= LTTNG_UST_PATCHLEVEL
;
248 v
->sublevel
= LTTNG_UST_SUBLEVEL
;
253 long lttng_abi_add_context(int objd
,
254 struct lttng_ust_context
*context_param
,
255 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
257 if (session
->been_active
)
260 switch (context_param
->ctx
) {
261 case LTTNG_UST_CONTEXT_PTHREAD_ID
:
262 return lttng_add_pthread_id_to_ctx(ctx
);
263 case LTTNG_UST_CONTEXT_VTID
:
264 return lttng_add_vtid_to_ctx(ctx
);
265 case LTTNG_UST_CONTEXT_VPID
:
266 return lttng_add_vpid_to_ctx(ctx
);
267 case LTTNG_UST_CONTEXT_PROCNAME
:
268 return lttng_add_procname_to_ctx(ctx
);
275 * lttng_cmd - lttng control through socket commands
277 * @objd: the object descriptor
281 * This descriptor implements lttng commands:
283 * Returns a LTTng trace session object descriptor
284 * LTTNG_UST_TRACER_VERSION
285 * Returns the LTTng kernel tracer version
286 * LTTNG_UST_TRACEPOINT_LIST
287 * Returns a file descriptor listing available tracepoints
288 * LTTNG_UST_WAIT_QUIESCENT
289 * Returns after all previously running probes have completed
291 * The returned session will be deleted when its file descriptor is closed.
294 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
297 case LTTNG_UST_SESSION
:
298 return lttng_abi_create_session();
299 case LTTNG_UST_TRACER_VERSION
:
300 return lttng_abi_tracer_version(objd
,
301 (struct lttng_ust_tracer_version
*) arg
);
302 case LTTNG_UST_TRACEPOINT_LIST
:
303 return lttng_abi_tracepoint_list();
304 case LTTNG_UST_WAIT_QUIESCENT
:
312 static const struct lttng_ust_objd_ops lttng_ops
= {
317 * We tolerate no failure in this function (if one happens, we print a dmesg
318 * error, but cannot return any error, because the channel information is
322 void lttng_metadata_create_events(int channel_objd
)
324 struct ltt_channel
*channel
= objd_private(channel_objd
);
325 static struct lttng_ust_event metadata_params
= {
326 .instrumentation
= LTTNG_UST_TRACEPOINT
,
327 .name
= "lttng_ust:metadata",
329 struct ltt_event
*event
;
332 * We tolerate no failure path after event creation. It will stay
333 * invariant for the rest of the session.
335 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
343 return; /* not allowed to return error */
346 int lttng_abi_create_channel(int session_objd
,
347 struct lttng_ust_channel
*chan_param
,
348 enum channel_type channel_type
)
350 struct ltt_session
*session
= objd_private(session_objd
);
351 const struct lttng_ust_objd_ops
*ops
;
352 const char *transport_name
;
353 struct ltt_channel
*chan
;
356 struct ltt_channel chan_priv_init
;
358 switch (channel_type
) {
359 case PER_CPU_CHANNEL
:
360 if (chan_param
->output
== LTTNG_UST_MMAP
) {
361 transport_name
= chan_param
->overwrite
?
362 "relay-overwrite-mmap" : "relay-discard-mmap";
366 ops
= <tng_channel_ops
;
368 case METADATA_CHANNEL
:
369 if (chan_param
->output
== LTTNG_UST_MMAP
)
370 transport_name
= "relay-metadata-mmap";
373 ops
= <tng_metadata_ops
;
376 transport_name
= "<unknown>";
379 chan_objd
= objd_alloc(NULL
, ops
);
384 memset(&chan_priv_init
, 0, sizeof(chan_priv_init
));
385 /* Copy of session UUID for consumer (availability through shm) */
386 memcpy(chan_priv_init
.uuid
, session
->uuid
, sizeof(session
->uuid
));
389 * We tolerate no failure path after channel creation. It will stay
390 * invariant for the rest of the session.
392 chan
= ltt_channel_create(session
, transport_name
, NULL
,
393 chan_param
->subbuf_size
,
394 chan_param
->num_subbuf
,
395 chan_param
->switch_timer_interval
,
396 chan_param
->read_timer_interval
,
398 &chan_param
->wait_fd
,
399 &chan_param
->memory_map_size
,
405 objd_set_private(chan_objd
, chan
);
406 chan
->objd
= chan_objd
;
407 if (channel_type
== METADATA_CHANNEL
) {
408 session
->metadata
= chan
;
409 lttng_metadata_create_events(chan_objd
);
411 /* The channel created holds a reference on the session */
412 objd_ref(session_objd
);
420 err
= lttng_ust_objd_unref(chan_objd
);
428 * lttng_session_cmd - lttng session object command
434 * This descriptor implements lttng commands:
436 * Returns a LTTng channel object descriptor
438 * Enables tracing for a session (weak enable)
440 * Disables tracing for a session (strong disable)
442 * Returns a LTTng metadata object descriptor
444 * The returned channel will be deleted when its file descriptor is closed.
447 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
449 struct ltt_session
*session
= objd_private(objd
);
452 case LTTNG_UST_CHANNEL
:
453 return lttng_abi_create_channel(objd
,
454 (struct lttng_ust_channel
*) arg
,
456 case LTTNG_UST_SESSION_START
:
457 case LTTNG_UST_ENABLE
:
458 return ltt_session_enable(session
);
459 case LTTNG_UST_SESSION_STOP
:
460 case LTTNG_UST_DISABLE
:
461 return ltt_session_disable(session
);
462 case LTTNG_UST_METADATA
:
463 return lttng_abi_create_channel(objd
,
464 (struct lttng_ust_channel
*) arg
,
472 * Called when the last file reference is dropped.
474 * Big fat note: channels and events are invariant for the whole session after
475 * their creation. So this session destruction also destroys all channel and
476 * event structures specific to this session (they are not destroyed when their
477 * individual file is released).
480 int lttng_release_session(int objd
)
482 struct ltt_session
*session
= objd_private(objd
);
485 ltt_session_destroy(session
);
492 static const struct lttng_ust_objd_ops lttng_session_ops
= {
493 .release
= lttng_release_session
,
494 .cmd
= lttng_session_cmd
,
498 * beware: we don't keep the mutex over the send, but we must walk the
499 * whole list each time we are called again. So sending one tracepoint
500 * at a time means this is O(n^2). TODO: do as in the kernel and send
501 * multiple tracepoints for each call to amortize this cost.
504 void ltt_tracepoint_list_get(struct ltt_tracepoint_list
*list
,
508 if (!list
->got_first
) {
509 tracepoint_iter_start(&list
->iter
);
513 tracepoint_iter_next(&list
->iter
);
515 if (!list
->iter
.tracepoint
) {
516 tp_list_entry
[0] = '\0'; /* end of list */
518 if (!strcmp((*list
->iter
.tracepoint
)->name
,
519 "lttng_ust:metadata"))
521 memcpy(tp_list_entry
, (*list
->iter
.tracepoint
)->name
,
522 LTTNG_UST_SYM_NAME_LEN
);
527 long lttng_tracepoint_list_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
529 struct ltt_tracepoint_list
*list
= objd_private(objd
);
530 char *str
= (char *) arg
;
533 case LTTNG_UST_TRACEPOINT_LIST_GET
:
534 ltt_tracepoint_list_get(list
, str
);
544 int lttng_abi_tracepoint_list(void)
547 struct ltt_tracepoint_list
*list
;
549 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
554 list
= zmalloc(sizeof(*list
));
559 objd_set_private(list_objd
, list
);
567 err
= lttng_ust_objd_unref(list_objd
);
575 int lttng_release_tracepoint_list(int objd
)
577 struct ltt_tracepoint_list
*list
= objd_private(objd
);
580 tracepoint_iter_stop(&list
->iter
);
588 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops
= {
589 .release
= lttng_release_tracepoint_list
,
590 .cmd
= lttng_tracepoint_list_cmd
,
593 struct stream_priv_data
{
594 struct lttng_ust_lib_ring_buffer
*buf
;
595 struct ltt_channel
*ltt_chan
;
599 int lttng_abi_open_stream(int channel_objd
, struct lttng_ust_stream
*info
)
601 struct ltt_channel
*channel
= objd_private(channel_objd
);
602 struct lttng_ust_lib_ring_buffer
*buf
;
603 struct stream_priv_data
*priv
;
604 int stream_objd
, ret
;
606 buf
= channel
->ops
->buffer_read_open(channel
->chan
, channel
->handle
,
607 &info
->shm_fd
, &info
->wait_fd
, &info
->memory_map_size
);
611 priv
= zmalloc(sizeof(*priv
));
617 priv
->ltt_chan
= channel
;
618 stream_objd
= objd_alloc(priv
, &lib_ring_buffer_objd_ops
);
619 if (stream_objd
< 0) {
623 /* Hold a reference on the channel object descriptor */
624 objd_ref(channel_objd
);
630 channel
->ops
->buffer_read_close(buf
, channel
->handle
);
635 int lttng_abi_create_event(int channel_objd
,
636 struct lttng_ust_event
*event_param
)
638 struct ltt_channel
*channel
= objd_private(channel_objd
);
639 struct ltt_event
*event
;
642 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
643 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
644 if (event_objd
< 0) {
649 * We tolerate no failure path after event creation. It will stay
650 * invariant for the rest of the session.
652 event
= ltt_event_create(channel
, event_param
, NULL
);
657 objd_set_private(event_objd
, event
);
658 /* The event holds a reference on the channel */
659 objd_ref(channel_objd
);
666 err
= lttng_ust_objd_unref(event_objd
);
674 * lttng_channel_cmd - lttng control through object descriptors
676 * @objd: the object descriptor
680 * This object descriptor implements lttng commands:
682 * Returns an event stream object descriptor or failure.
683 * (typically, one event stream records events from one CPU)
685 * Returns an event object descriptor or failure.
687 * Prepend a context field to each event in the channel
689 * Enable recording for events in this channel (weak enable)
691 * Disable recording for events in this channel (strong disable)
693 * Channel and event file descriptors also hold a reference on the session.
696 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
698 struct ltt_channel
*channel
= objd_private(objd
);
701 case LTTNG_UST_STREAM
:
703 struct lttng_ust_stream
*stream
;
705 stream
= (struct lttng_ust_stream
*) arg
;
706 /* stream used as output */
707 return lttng_abi_open_stream(objd
, stream
);
709 case LTTNG_UST_EVENT
:
710 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
711 case LTTNG_UST_CONTEXT
:
712 return lttng_abi_add_context(objd
,
713 (struct lttng_ust_context
*) arg
,
714 &channel
->ctx
, channel
->session
);
715 case LTTNG_UST_ENABLE
:
716 return ltt_channel_enable(channel
);
717 case LTTNG_UST_DISABLE
:
718 return ltt_channel_disable(channel
);
719 case LTTNG_UST_FLUSH_BUFFER
:
720 return channel
->ops
->flush_buffer(channel
->chan
, channel
->handle
);
727 * lttng_metadata_cmd - lttng control through object descriptors
729 * @objd: the object descriptor
733 * This object descriptor implements lttng commands:
735 * Returns an event stream file descriptor or failure.
737 * Channel and event file descriptors also hold a reference on the session.
740 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
742 struct ltt_channel
*channel
= objd_private(objd
);
745 case LTTNG_UST_STREAM
:
747 struct lttng_ust_stream
*stream
;
749 stream
= (struct lttng_ust_stream
*) arg
;
750 /* stream used as output */
751 return lttng_abi_open_stream(objd
, stream
);
753 case LTTNG_UST_FLUSH_BUFFER
:
754 return channel
->ops
->flush_buffer(channel
->chan
, channel
->handle
);
762 * lttng_channel_poll - lttng stream addition/removal monitoring
767 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
769 struct ltt_channel
*channel
= file
->private_data
;
770 unsigned int mask
= 0;
772 if (file
->f_mode
& FMODE_READ
) {
773 poll_wait_set_exclusive(wait
);
774 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
777 if (channel
->ops
->is_disabled(channel
->chan
))
779 if (channel
->ops
->is_finalized(channel
->chan
))
781 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
782 return POLLIN
| POLLRDNORM
;
791 int lttng_channel_release(int objd
)
793 struct ltt_channel
*channel
= objd_private(objd
);
796 return lttng_ust_objd_unref(channel
->session
->objd
);
800 static const struct lttng_ust_objd_ops lttng_channel_ops
= {
801 .release
= lttng_channel_release
,
802 //.poll = lttng_channel_poll,
803 .cmd
= lttng_channel_cmd
,
806 static const struct lttng_ust_objd_ops lttng_metadata_ops
= {
807 .release
= lttng_channel_release
,
808 .cmd
= lttng_metadata_cmd
,
812 * lttng_rb_cmd - lttng ring buffer control through object descriptors
814 * @objd: the object descriptor
818 * This object descriptor implements lttng commands:
819 * (None for now. Access is done directly though shm.)
822 long lttng_rb_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
831 int lttng_rb_release(int objd
)
833 struct stream_priv_data
*priv
= objd_private(objd
);
834 struct lttng_ust_lib_ring_buffer
*buf
;
835 struct ltt_channel
*channel
;
839 channel
= priv
->ltt_chan
;
842 * If we are at ABI exit, we don't want to close the
843 * buffer opened for read: it is being shared between
844 * the parent and child (right after fork), and we don't
845 * want the child to close it for the parent. For a real
846 * exit, we don't care about marking it as closed, as
847 * the consumer daemon (if there is one) will do fine
848 * even if we don't mark it as "closed" for reading on
850 * We only mark it as closed if it is being explicitely
851 * released by the session daemon with an explicit
854 if (!lttng_ust_abi_close_in_progress
)
855 channel
->ops
->buffer_read_close(buf
, channel
->handle
);
857 return lttng_ust_objd_unref(channel
->objd
);
862 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops
= {
863 .release
= lttng_rb_release
,
868 * lttng_event_cmd - lttng control through object descriptors
870 * @objd: the object descriptor
874 * This object descriptor implements lttng commands:
876 * Prepend a context field to each record of this event
878 * Enable recording for this event (weak enable)
880 * Disable recording for this event (strong disable)
883 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
885 struct ltt_event
*event
= objd_private(objd
);
888 case LTTNG_UST_CONTEXT
:
889 return lttng_abi_add_context(objd
,
890 (struct lttng_ust_context
*) arg
,
891 &event
->ctx
, event
->chan
->session
);
892 case LTTNG_UST_ENABLE
:
893 return ltt_event_enable(event
);
894 case LTTNG_UST_DISABLE
:
895 return ltt_event_disable(event
);
902 int lttng_event_release(int objd
)
904 struct ltt_event
*event
= objd_private(objd
);
907 return lttng_ust_objd_unref(event
->chan
->objd
);
911 /* TODO: filter control ioctl */
912 static const struct lttng_ust_objd_ops lttng_event_ops
= {
913 .release
= lttng_event_release
,
914 .cmd
= lttng_event_cmd
,
917 void lttng_ust_abi_exit(void)
919 lttng_ust_abi_close_in_progress
= 1;
920 objd_table_destroy();
921 lttng_ust_abi_close_in_progress
= 0;