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 <ust/lttng-ust-abi.h>
28 #include <urcu/compiler.h>
29 #include <urcu/list.h>
30 #include <ust/lttng-events.h>
31 #include <ust/usterr-signal-safe.h>
33 #include "ltt-tracer.h"
36 * Object descriptor table. Should be protected from concurrent access
43 long (*cmd
)(int objd
, unsigned int cmd
, unsigned long arg
);
44 int (*release
)(int objd
);
51 const struct objd_ops
*ops
;
54 int freelist_next
; /* offset freelist. end is -1. */
60 unsigned int len
, allocated_len
;
61 int freelist_head
; /* offset freelist head. end is -1 */
64 static struct objd_table objd_table
= {
69 int objd_alloc(void *private_data
, const struct objd_ops
*ops
)
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 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 obj
) * new_allocated_len
);
92 memcpy(new_table
, old_table
,
93 sizeof(struct 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
= 1;
104 return obj
- objd_table
.array
;
108 struct obj
*_objd_get(int id
)
110 if (id
>= objd_table
.len
)
112 return &objd_table
.array
[id
];
116 void *objd_private(int id
)
118 struct obj
*obj
= _objd_get(id
);
120 return obj
->u
.s
.private_data
;
124 void objd_set_private(int id
, void *private_data
)
126 struct obj
*obj
= _objd_get(id
);
128 obj
->u
.s
.private_data
= private_data
;
132 const struct objd_ops
*objd_ops(int id
)
134 struct obj
*obj
= _objd_get(id
);
140 void objd_free(int id
)
142 struct obj
*obj
= _objd_get(id
);
145 obj
->u
.freelist_next
= objd_table
.freelist_head
;
146 objd_table
.freelist_head
= obj
- objd_table
.array
;
150 void objd_ref(int id
)
152 struct obj
*obj
= _objd_get(id
);
156 int objd_unref(int id
)
158 struct obj
*obj
= _objd_get(id
);
162 if (!(--obj
->u
.s
.f_count
)) {
163 const struct objd_ops
*ops
= objd_ops(id
);
173 void objd_table_destroy(void)
175 free(objd_table
.array
);
179 * This is LTTng's own personal way to create an ABI for sessiond.
180 * We send commands over a socket.
183 static const struct objd_ops lttng_ops
;
184 static const struct objd_ops lttng_session_ops
;
185 static const struct objd_ops lttng_channel_ops
;
186 static const struct objd_ops lttng_metadata_ops
;
187 static const struct objd_ops lttng_event_ops
;
194 int lttng_abi_create_session(void)
196 struct ltt_session
*session
;
197 int session_objd
, ret
;
199 session
= ltt_session_create();
202 session_objd
= objd_alloc(session
, <tng_session_ops
);
203 if (session_objd
< 0) {
207 session
->objd
= session_objd
;
211 ltt_session_destroy(session
);
217 int lttng_abi_tracepoint_list(void)
221 /* TODO: Create list private data */
222 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
236 long lttng_abi_tracer_version(int objd
,
237 struct lttng_ust_tracer_version
*v
)
239 v
->version
= LTTNG_UST_VERSION
;
240 v
->patchlevel
= LTTNG_UST_PATCHLEVEL
;
241 v
->sublevel
= LTTNG_UST_SUBLEVEL
;
246 long lttng_abi_add_context(int objd
,
247 struct lttng_ust_context
*context_param
,
248 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
250 if (session
->been_active
)
253 switch (context_param
->ctx
) {
254 case LTTNG_UST_CONTEXT_VTID
:
255 //TODO return lttng_add_vtid_to_ctx(ctx);
262 * lttng_cmd - lttng control through socket commands
264 * @objd: the object descriptor
268 * This descriptor implements lttng commands:
270 * Returns a LTTng trace session object descriptor
271 * LTTNG_UST_TRACER_VERSION
272 * Returns the LTTng kernel tracer version
273 * LTTNG_UST_TRACEPOINT_LIST
274 * Returns a file descriptor listing available tracepoints
275 * LTTNG_UST_WAIT_QUIESCENT
276 * Returns after all previously running probes have completed
278 * The returned session will be deleted when its file descriptor is closed.
281 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
284 case LTTNG_UST_SESSION
:
285 return lttng_abi_create_session();
286 case LTTNG_UST_TRACER_VERSION
:
287 return lttng_abi_tracer_version(objd
,
288 (struct lttng_ust_tracer_version
*) arg
);
289 case LTTNG_UST_TRACEPOINT_LIST
:
290 return -ENOSYS
; //TODO
291 //return lttng_abi_tracepoint_list();
292 case LTTNG_UST_WAIT_QUIESCENT
:
300 static const struct objd_ops lttng_ops
= {
305 * We tolerate no failure in this function (if one happens, we print a dmesg
306 * error, but cannot return any error, because the channel information is
310 void lttng_metadata_create_events(int channel_objd
)
312 struct ltt_channel
*channel
= objd_private(channel_objd
);
313 static struct lttng_ust_event metadata_params
= {
314 .instrumentation
= LTTNG_UST_TRACEPOINT
,
315 .name
= "lttng_metadata",
317 struct ltt_event
*event
;
321 * We tolerate no failure path after event creation. It will stay
322 * invariant for the rest of the session.
324 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
333 return; /* not allowed to return error */
337 int lttng_abi_create_channel(int session_objd
,
338 struct lttng_ust_channel
*chan_param
,
339 enum channel_type channel_type
)
341 struct ltt_session
*session
= objd_private(session_objd
);
342 const struct objd_ops
*ops
;
343 const char *transport_name
;
344 struct ltt_channel
*chan
;
348 chan_objd
= objd_alloc(NULL
, <tng_channel_ops
);
353 switch (channel_type
) {
354 case PER_CPU_CHANNEL
:
355 if (chan_param
->output
== LTTNG_UST_MMAP
) {
356 transport_name
= chan_param
->overwrite
?
357 "relay-overwrite-mmap" : "relay-discard-mmap";
361 ops
= <tng_channel_ops
;
363 case METADATA_CHANNEL
:
364 if (chan_param
->output
== LTTNG_UST_MMAP
)
365 transport_name
= "relay-metadata-mmap";
368 ops
= <tng_metadata_ops
;
371 transport_name
= "<unknown>";
375 * We tolerate no failure path after channel creation. It will stay
376 * invariant for the rest of the session.
378 chan
= ltt_channel_create(session
, transport_name
, NULL
,
379 chan_param
->subbuf_size
,
380 chan_param
->num_subbuf
,
381 chan_param
->switch_timer_interval
,
382 chan_param
->read_timer_interval
);
387 objd_set_private(chan_objd
, chan
);
388 chan
->objd
= chan_objd
;
389 if (channel_type
== METADATA_CHANNEL
) {
390 session
->metadata
= chan
;
391 lttng_metadata_create_events(chan_objd
);
394 /* The channel created holds a reference on the session */
395 objd_ref(session_objd
);
403 err
= objd_unref(chan_objd
);
411 * lttng_session_cmd - lttng session object command
417 * This descriptor implements lttng commands:
419 * Returns a LTTng channel object descriptor
421 * Enables tracing for a session (weak enable)
423 * Disables tracing for a session (strong disable)
425 * Returns a LTTng metadata object descriptor
427 * The returned channel will be deleted when its file descriptor is closed.
430 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
432 struct ltt_session
*session
= objd_private(objd
);
435 case LTTNG_UST_CHANNEL
:
436 return lttng_abi_create_channel(objd
,
437 (struct lttng_ust_channel
*) arg
,
439 case LTTNG_UST_SESSION_START
:
440 case LTTNG_UST_ENABLE
:
441 return ltt_session_enable(session
);
442 case LTTNG_UST_SESSION_STOP
:
443 case LTTNG_UST_DISABLE
:
444 return ltt_session_disable(session
);
445 case LTTNG_UST_METADATA
:
446 return lttng_abi_create_channel(objd
,
447 (struct lttng_ust_channel
*) arg
,
455 * Called when the last file reference is dropped.
457 * Big fat note: channels and events are invariant for the whole session after
458 * their creation. So this session destruction also destroys all channel and
459 * event structures specific to this session (they are not destroyed when their
460 * individual file is released).
463 int lttng_release_session(int objd
)
465 struct ltt_session
*session
= objd_private(objd
);
468 ltt_session_destroy(session
);
475 static const struct objd_ops lttng_session_ops
= {
476 .release
= lttng_release_session
,
477 .cmd
= lttng_session_cmd
,
482 int lttng_abi_open_stream(int channel_objd
)
484 struct ltt_channel
*channel
= objd_private(channel_objd
);
485 struct lib_ring_buffer
*buf
;
486 int stream_objd
, ret
;
488 buf
= channel
->ops
->buffer_read_open(channel
->chan
);
492 stream_objd
= objd_alloc(buf
, &lib_ring_buffer_objd_ops
);
493 if (stream_objd
< 0) {
498 * The stream holds a reference to the channel within the generic ring
499 * buffer library, so no need to hold a refcount on the channel and
500 * session files here.
505 channel
->ops
->buffer_read_close(buf
);
511 int lttng_abi_create_event(int channel_objd
,
512 struct lttng_ust_event
*event_param
)
514 struct ltt_channel
*channel
= objd_private(channel_objd
);
515 struct ltt_event
*event
;
518 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
519 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
520 if (event_objd
< 0) {
525 * We tolerate no failure path after event creation. It will stay
526 * invariant for the rest of the session.
528 event
= ltt_event_create(channel
, event_param
, NULL
);
533 objd_set_private(event_objd
, event
);
534 /* The event holds a reference on the channel */
535 objd_ref(channel_objd
);
542 err
= objd_unref(event_objd
);
550 * lttng_channel_cmd - lttng control through object descriptors
552 * @objd: the object descriptor
556 * This object descriptor implements lttng commands:
558 * Returns an event stream object descriptor or failure.
559 * (typically, one event stream records events from one CPU)
561 * Returns an event object descriptor or failure.
563 * Prepend a context field to each event in the channel
565 * Enable recording for events in this channel (weak enable)
567 * Disable recording for events in this channel (strong disable)
569 * Channel and event file descriptors also hold a reference on the session.
572 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
574 struct ltt_channel
*channel
= objd_private(objd
);
577 case LTTNG_UST_STREAM
:
578 return -ENOSYS
; //TODO
579 //return lttng_abi_open_stream(objd);
580 case LTTNG_UST_EVENT
:
581 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
582 case LTTNG_UST_CONTEXT
:
583 return lttng_abi_add_context(objd
,
584 (struct lttng_ust_context
*) arg
,
585 &channel
->ctx
, channel
->session
);
586 case LTTNG_UST_ENABLE
:
587 return ltt_channel_enable(channel
);
588 case LTTNG_UST_DISABLE
:
589 return ltt_channel_disable(channel
);
596 * lttng_metadata_cmd - lttng control through object descriptors
598 * @objd: the object descriptor
602 * This object descriptor implements lttng commands:
604 * Returns an event stream file descriptor or failure.
606 * Channel and event file descriptors also hold a reference on the session.
609 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
612 case LTTNG_UST_STREAM
:
613 return -ENOSYS
; //TODO
614 //return lttng_abi_open_stream(objd);
622 * lttng_channel_poll - lttng stream addition/removal monitoring
627 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
629 struct ltt_channel
*channel
= file
->private_data
;
630 unsigned int mask
= 0;
632 if (file
->f_mode
& FMODE_READ
) {
633 poll_wait_set_exclusive(wait
);
634 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
637 if (channel
->ops
->is_disabled(channel
->chan
))
639 if (channel
->ops
->is_finalized(channel
->chan
))
641 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
642 return POLLIN
| POLLRDNORM
;
651 int lttng_channel_release(int objd
)
653 struct ltt_channel
*channel
= objd_private(objd
);
656 return objd_unref(channel
->session
->objd
);
660 static const struct objd_ops lttng_channel_ops
= {
661 .release
= lttng_channel_release
,
662 //.poll = lttng_channel_poll,
663 .cmd
= lttng_channel_cmd
,
666 static const struct objd_ops lttng_metadata_ops
= {
667 .release
= lttng_channel_release
,
668 .cmd
= lttng_metadata_cmd
,
672 * lttng_event_cmd - lttng control through object descriptors
674 * @objd: the object descriptor
678 * This object descriptor implements lttng commands:
680 * Prepend a context field to each record of this event
682 * Enable recording for this event (weak enable)
684 * Disable recording for this event (strong disable)
687 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
689 struct ltt_event
*event
= objd_private(objd
);
692 case LTTNG_UST_CONTEXT
:
693 return lttng_abi_add_context(objd
,
694 (struct lttng_ust_context
*) arg
,
695 &event
->ctx
, event
->chan
->session
);
696 case LTTNG_UST_ENABLE
:
697 return ltt_event_enable(event
);
698 case LTTNG_UST_DISABLE
:
699 return ltt_event_disable(event
);
706 int lttng_event_release(int objd
)
708 struct ltt_event
*event
= objd_private(objd
);
711 return objd_unref(event
->chan
->objd
);
715 /* TODO: filter control ioctl */
716 static const struct objd_ops lttng_event_ops
= {
717 .release
= lttng_event_release
,
718 .cmd
= lttng_event_cmd
,
721 void lttng_ust_abi_exit(void)
723 objd_table_destroy();