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
44 const struct objd_ops
*ops
;
47 int freelist_next
; /* offset freelist. end is -1. */
53 unsigned int len
, allocated_len
;
54 int freelist_head
; /* offset freelist head. end is -1 */
57 static struct objd_table objd_table
= {
62 int objd_alloc(void *private_data
, const struct objd_ops
*ops
)
66 if (objd_table
.freelist_head
!= -1) {
67 obj
= &objd_table
.array
[objd_table
.freelist_head
];
68 objd_table
.freelist_head
= obj
->u
.freelist_next
;
72 if (objd_table
.len
>= objd_table
.allocated_len
) {
73 unsigned int new_allocated_len
, old_allocated_len
;
74 struct obj
*new_table
, *old_table
;
76 old_allocated_len
= objd_table
.allocated_len
;
77 old_table
= objd_table
.array
;
78 if (!old_allocated_len
)
79 new_allocated_len
= 1;
81 new_allocated_len
= old_allocated_len
<< 1;
82 new_table
= zmalloc(sizeof(struct obj
) * new_allocated_len
);
85 memcpy(new_table
, old_table
,
86 sizeof(struct obj
) * old_allocated_len
);
88 objd_table
.array
= new_table
;
89 objd_table
.allocated_len
= new_allocated_len
;
91 obj
= &objd_table
.array
[objd_table
.len
];
94 obj
->u
.s
.private_data
= private_data
;
96 obj
->u
.s
.f_count
= 2; /* count == 1 : object is allocated */
97 /* count == 2 : allocated + hold ref */
98 return obj
- objd_table
.array
;
102 struct obj
*_objd_get(int id
)
104 if (id
>= objd_table
.len
)
106 if (!objd_table
.array
[id
].u
.s
.f_count
)
108 return &objd_table
.array
[id
];
112 void *objd_private(int id
)
114 struct obj
*obj
= _objd_get(id
);
116 return obj
->u
.s
.private_data
;
120 void objd_set_private(int id
, void *private_data
)
122 struct obj
*obj
= _objd_get(id
);
124 obj
->u
.s
.private_data
= private_data
;
127 const struct objd_ops
*objd_ops(int id
)
129 struct obj
*obj
= _objd_get(id
);
137 void objd_free(int id
)
139 struct obj
*obj
= _objd_get(id
);
142 obj
->u
.freelist_next
= objd_table
.freelist_head
;
143 objd_table
.freelist_head
= obj
- objd_table
.array
;
144 assert(obj
->u
.s
.f_count
== 1);
145 obj
->u
.s
.f_count
= 0; /* deallocated */
149 void objd_ref(int id
)
151 struct obj
*obj
= _objd_get(id
);
155 int objd_unref(int id
)
157 struct obj
*obj
= _objd_get(id
);
161 if (obj
->u
.s
.f_count
== 1) {
162 ERR("Reference counting error\n");
165 if ((--obj
->u
.s
.f_count
) == 1) {
166 const struct objd_ops
*ops
= objd_ops(id
);
176 void objd_table_destroy(void)
180 for (i
= 0; i
< objd_table
.allocated_len
; i
++) {
181 struct obj
*obj
= _objd_get(i
);
182 const struct objd_ops
*ops
;
190 free(objd_table
.array
);
191 objd_table
.array
= NULL
;
193 objd_table
.allocated_len
= 0;
194 objd_table
.freelist_head
= -1;
198 * This is LTTng's own personal way to create an ABI for sessiond.
199 * We send commands over a socket.
202 static const struct objd_ops lttng_ops
;
203 static const struct objd_ops lttng_session_ops
;
204 static const struct objd_ops lttng_channel_ops
;
205 static const struct objd_ops lttng_metadata_ops
;
206 static const struct objd_ops lttng_event_ops
;
207 static const struct objd_ops lib_ring_buffer_objd_ops
;
214 int lttng_abi_create_root_handle(void)
218 root_handle
= objd_alloc(NULL
, <tng_ops
);
219 assert(root_handle
== 0);
224 int lttng_abi_create_session(void)
226 struct ltt_session
*session
;
227 int session_objd
, ret
;
229 session
= ltt_session_create();
232 session_objd
= objd_alloc(session
, <tng_session_ops
);
233 if (session_objd
< 0) {
237 session
->objd
= session_objd
;
241 ltt_session_destroy(session
);
247 int lttng_abi_tracepoint_list(void)
251 /* TODO: Create list private data */
252 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
266 long lttng_abi_tracer_version(int objd
,
267 struct lttng_ust_tracer_version
*v
)
269 v
->version
= LTTNG_UST_VERSION
;
270 v
->patchlevel
= LTTNG_UST_PATCHLEVEL
;
271 v
->sublevel
= LTTNG_UST_SUBLEVEL
;
276 long lttng_abi_add_context(int objd
,
277 struct lttng_ust_context
*context_param
,
278 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
280 if (session
->been_active
)
283 switch (context_param
->ctx
) {
284 case LTTNG_UST_CONTEXT_VTID
:
285 //TODO return lttng_add_vtid_to_ctx(ctx);
292 * lttng_cmd - lttng control through socket commands
294 * @objd: the object descriptor
298 * This descriptor implements lttng commands:
300 * Returns a LTTng trace session object descriptor
301 * LTTNG_UST_TRACER_VERSION
302 * Returns the LTTng kernel tracer version
303 * LTTNG_UST_TRACEPOINT_LIST
304 * Returns a file descriptor listing available tracepoints
305 * LTTNG_UST_WAIT_QUIESCENT
306 * Returns after all previously running probes have completed
308 * The returned session will be deleted when its file descriptor is closed.
311 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
314 case LTTNG_UST_SESSION
:
315 return lttng_abi_create_session();
316 case LTTNG_UST_TRACER_VERSION
:
317 return lttng_abi_tracer_version(objd
,
318 (struct lttng_ust_tracer_version
*) arg
);
319 case LTTNG_UST_TRACEPOINT_LIST
:
320 return -ENOSYS
; //TODO
321 //return lttng_abi_tracepoint_list();
322 case LTTNG_UST_WAIT_QUIESCENT
:
330 static const struct objd_ops lttng_ops
= {
335 * We tolerate no failure in this function (if one happens, we print a dmesg
336 * error, but cannot return any error, because the channel information is
340 void lttng_metadata_create_events(int channel_objd
)
342 struct ltt_channel
*channel
= objd_private(channel_objd
);
343 static struct lttng_ust_event metadata_params
= {
344 .instrumentation
= LTTNG_UST_TRACEPOINT
,
345 .name
= "lttng_metadata",
347 struct ltt_event
*event
;
351 * We tolerate no failure path after event creation. It will stay
352 * invariant for the rest of the session.
354 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
363 return; /* not allowed to return error */
366 int lttng_abi_create_channel(int session_objd
,
367 struct lttng_ust_channel
*chan_param
,
368 enum channel_type channel_type
)
370 struct ltt_session
*session
= objd_private(session_objd
);
371 const struct objd_ops
*ops
;
372 const char *transport_name
;
373 struct ltt_channel
*chan
;
377 chan_objd
= objd_alloc(NULL
, <tng_channel_ops
);
382 switch (channel_type
) {
383 case PER_CPU_CHANNEL
:
384 if (chan_param
->output
== LTTNG_UST_MMAP
) {
385 transport_name
= chan_param
->overwrite
?
386 "relay-overwrite-mmap" : "relay-discard-mmap";
390 ops
= <tng_channel_ops
;
392 case METADATA_CHANNEL
:
393 if (chan_param
->output
== LTTNG_UST_MMAP
)
394 transport_name
= "relay-metadata-mmap";
397 ops
= <tng_metadata_ops
;
400 transport_name
= "<unknown>";
404 * We tolerate no failure path after channel creation. It will stay
405 * invariant for the rest of the session.
407 chan
= ltt_channel_create(session
, transport_name
, NULL
,
408 chan_param
->subbuf_size
,
409 chan_param
->num_subbuf
,
410 chan_param
->switch_timer_interval
,
411 chan_param
->read_timer_interval
,
413 &chan_param
->wait_fd
,
414 &chan_param
->memory_map_size
);
419 objd_set_private(chan_objd
, chan
);
420 chan
->objd
= chan_objd
;
421 if (channel_type
== METADATA_CHANNEL
) {
422 session
->metadata
= chan
;
423 lttng_metadata_create_events(chan_objd
);
426 /* The channel created holds a reference on the session */
427 objd_ref(session_objd
);
435 err
= objd_unref(chan_objd
);
443 * lttng_session_cmd - lttng session object command
449 * This descriptor implements lttng commands:
451 * Returns a LTTng channel object descriptor
453 * Enables tracing for a session (weak enable)
455 * Disables tracing for a session (strong disable)
457 * Returns a LTTng metadata object descriptor
459 * The returned channel will be deleted when its file descriptor is closed.
462 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
464 struct ltt_session
*session
= objd_private(objd
);
467 case LTTNG_UST_CHANNEL
:
468 return lttng_abi_create_channel(objd
,
469 (struct lttng_ust_channel
*) arg
,
471 case LTTNG_UST_SESSION_START
:
472 case LTTNG_UST_ENABLE
:
473 return ltt_session_enable(session
);
474 case LTTNG_UST_SESSION_STOP
:
475 case LTTNG_UST_DISABLE
:
476 return ltt_session_disable(session
);
477 case LTTNG_UST_METADATA
:
478 return lttng_abi_create_channel(objd
,
479 (struct lttng_ust_channel
*) arg
,
487 * Called when the last file reference is dropped.
489 * Big fat note: channels and events are invariant for the whole session after
490 * their creation. So this session destruction also destroys all channel and
491 * event structures specific to this session (they are not destroyed when their
492 * individual file is released).
495 int lttng_release_session(int objd
)
497 struct ltt_session
*session
= objd_private(objd
);
500 ltt_session_destroy(session
);
507 static const struct objd_ops lttng_session_ops
= {
508 .release
= lttng_release_session
,
509 .cmd
= lttng_session_cmd
,
512 struct stream_priv_data
{
513 struct lib_ring_buffer
*buf
;
514 struct ltt_channel
*ltt_chan
;
518 int lttng_abi_open_stream(int channel_objd
, struct lttng_ust_stream
*info
)
520 struct ltt_channel
*channel
= objd_private(channel_objd
);
521 struct lib_ring_buffer
*buf
;
522 struct stream_priv_data
*priv
;
523 int stream_objd
, ret
;
525 buf
= channel
->ops
->buffer_read_open(channel
->chan
, channel
->handle
,
526 &info
->shm_fd
, &info
->wait_fd
, &info
->memory_map_size
);
530 priv
= zmalloc(sizeof(*priv
));
536 priv
->ltt_chan
= channel
;
537 stream_objd
= objd_alloc(priv
, &lib_ring_buffer_objd_ops
);
538 if (stream_objd
< 0) {
542 /* Hold a reference on the channel object descriptor */
543 objd_ref(channel_objd
);
549 channel
->ops
->buffer_read_close(buf
, channel
->handle
);
554 int lttng_abi_create_event(int channel_objd
,
555 struct lttng_ust_event
*event_param
)
557 struct ltt_channel
*channel
= objd_private(channel_objd
);
558 struct ltt_event
*event
;
561 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
562 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
563 if (event_objd
< 0) {
568 * We tolerate no failure path after event creation. It will stay
569 * invariant for the rest of the session.
571 event
= ltt_event_create(channel
, event_param
, NULL
);
576 objd_set_private(event_objd
, event
);
577 /* The event holds a reference on the channel */
578 objd_ref(channel_objd
);
585 err
= objd_unref(event_objd
);
593 * lttng_channel_cmd - lttng control through object descriptors
595 * @objd: the object descriptor
599 * This object descriptor implements lttng commands:
601 * Returns an event stream object descriptor or failure.
602 * (typically, one event stream records events from one CPU)
604 * Returns an event object descriptor or failure.
606 * Prepend a context field to each event in the channel
608 * Enable recording for events in this channel (weak enable)
610 * Disable recording for events in this channel (strong disable)
612 * Channel and event file descriptors also hold a reference on the session.
615 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
617 struct ltt_channel
*channel
= objd_private(objd
);
620 case LTTNG_UST_STREAM
:
622 struct lttng_ust_stream
*stream
;
624 stream
= (struct lttng_ust_stream
*) arg
;
625 /* stream used as output */
626 return lttng_abi_open_stream(objd
, stream
);
628 case LTTNG_UST_EVENT
:
629 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
630 case LTTNG_UST_CONTEXT
:
631 return lttng_abi_add_context(objd
,
632 (struct lttng_ust_context
*) arg
,
633 &channel
->ctx
, channel
->session
);
634 case LTTNG_UST_ENABLE
:
635 return ltt_channel_enable(channel
);
636 case LTTNG_UST_DISABLE
:
637 return ltt_channel_disable(channel
);
644 * lttng_metadata_cmd - lttng control through object descriptors
646 * @objd: the object descriptor
650 * This object descriptor implements lttng commands:
652 * Returns an event stream file descriptor or failure.
654 * Channel and event file descriptors also hold a reference on the session.
657 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
660 case LTTNG_UST_STREAM
:
662 struct lttng_ust_stream
*stream
;
664 stream
= (struct lttng_ust_stream
*) arg
;
665 /* stream used as output */
666 return lttng_abi_open_stream(objd
, stream
);
675 * lttng_channel_poll - lttng stream addition/removal monitoring
680 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
682 struct ltt_channel
*channel
= file
->private_data
;
683 unsigned int mask
= 0;
685 if (file
->f_mode
& FMODE_READ
) {
686 poll_wait_set_exclusive(wait
);
687 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
690 if (channel
->ops
->is_disabled(channel
->chan
))
692 if (channel
->ops
->is_finalized(channel
->chan
))
694 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
695 return POLLIN
| POLLRDNORM
;
704 int lttng_channel_release(int objd
)
706 struct ltt_channel
*channel
= objd_private(objd
);
709 return objd_unref(channel
->session
->objd
);
713 static const struct objd_ops lttng_channel_ops
= {
714 .release
= lttng_channel_release
,
715 //.poll = lttng_channel_poll,
716 .cmd
= lttng_channel_cmd
,
719 static const struct objd_ops lttng_metadata_ops
= {
720 .release
= lttng_channel_release
,
721 .cmd
= lttng_metadata_cmd
,
725 * lttng_rb_cmd - lttng ring buffer control through object descriptors
727 * @objd: the object descriptor
731 * This object descriptor implements lttng commands:
732 * (None for now. Access is done directly though shm.)
733 * TODO: Add buffer flush.
736 long lttng_rb_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
738 struct stream_priv_data
*priv
= objd_private(objd
);
747 int lttng_rb_release(int objd
)
749 struct stream_priv_data
*priv
= objd_private(objd
);
750 struct lib_ring_buffer
*buf
;
751 struct ltt_channel
*channel
;
755 channel
= priv
->ltt_chan
;
758 return objd_unref(channel
->objd
);
763 static const struct objd_ops lib_ring_buffer_objd_ops
= {
764 .release
= lttng_rb_release
,
769 * lttng_event_cmd - lttng control through object descriptors
771 * @objd: the object descriptor
775 * This object descriptor implements lttng commands:
777 * Prepend a context field to each record of this event
779 * Enable recording for this event (weak enable)
781 * Disable recording for this event (strong disable)
784 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
786 struct ltt_event
*event
= objd_private(objd
);
789 case LTTNG_UST_CONTEXT
:
790 return lttng_abi_add_context(objd
,
791 (struct lttng_ust_context
*) arg
,
792 &event
->ctx
, event
->chan
->session
);
793 case LTTNG_UST_ENABLE
:
794 return ltt_event_enable(event
);
795 case LTTNG_UST_DISABLE
:
796 return ltt_event_disable(event
);
803 int lttng_event_release(int objd
)
805 struct ltt_event
*event
= objd_private(objd
);
808 return objd_unref(event
->chan
->objd
);
812 /* TODO: filter control ioctl */
813 static const struct objd_ops lttng_event_ops
= {
814 .release
= lttng_event_release
,
815 .cmd
= lttng_event_cmd
,
818 void lttng_ust_abi_exit(void)
820 objd_table_destroy();