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
;
213 int lttng_abi_create_root_handle(void)
217 root_handle
= objd_alloc(NULL
, <tng_ops
);
218 assert(root_handle
== 0);
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
);
246 int lttng_abi_tracepoint_list(void)
250 /* TODO: Create list private data */
251 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
265 long lttng_abi_tracer_version(int objd
,
266 struct lttng_ust_tracer_version
*v
)
268 v
->version
= LTTNG_UST_VERSION
;
269 v
->patchlevel
= LTTNG_UST_PATCHLEVEL
;
270 v
->sublevel
= LTTNG_UST_SUBLEVEL
;
275 long lttng_abi_add_context(int objd
,
276 struct lttng_ust_context
*context_param
,
277 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
279 if (session
->been_active
)
282 switch (context_param
->ctx
) {
283 case LTTNG_UST_CONTEXT_VTID
:
284 //TODO return lttng_add_vtid_to_ctx(ctx);
291 * lttng_cmd - lttng control through socket commands
293 * @objd: the object descriptor
297 * This descriptor implements lttng commands:
299 * Returns a LTTng trace session object descriptor
300 * LTTNG_UST_TRACER_VERSION
301 * Returns the LTTng kernel tracer version
302 * LTTNG_UST_TRACEPOINT_LIST
303 * Returns a file descriptor listing available tracepoints
304 * LTTNG_UST_WAIT_QUIESCENT
305 * Returns after all previously running probes have completed
307 * The returned session will be deleted when its file descriptor is closed.
310 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
313 case LTTNG_UST_SESSION
:
314 return lttng_abi_create_session();
315 case LTTNG_UST_TRACER_VERSION
:
316 return lttng_abi_tracer_version(objd
,
317 (struct lttng_ust_tracer_version
*) arg
);
318 case LTTNG_UST_TRACEPOINT_LIST
:
319 return -ENOSYS
; //TODO
320 //return lttng_abi_tracepoint_list();
321 case LTTNG_UST_WAIT_QUIESCENT
:
329 static const struct objd_ops lttng_ops
= {
334 * We tolerate no failure in this function (if one happens, we print a dmesg
335 * error, but cannot return any error, because the channel information is
339 void lttng_metadata_create_events(int channel_objd
)
341 struct ltt_channel
*channel
= objd_private(channel_objd
);
342 static struct lttng_ust_event metadata_params
= {
343 .instrumentation
= LTTNG_UST_TRACEPOINT
,
344 .name
= "lttng_metadata",
346 struct ltt_event
*event
;
350 * We tolerate no failure path after event creation. It will stay
351 * invariant for the rest of the session.
353 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
362 return; /* not allowed to return error */
365 int lttng_abi_create_channel(int session_objd
,
366 struct lttng_ust_channel
*chan_param
,
367 enum channel_type channel_type
)
369 struct ltt_session
*session
= objd_private(session_objd
);
370 const struct objd_ops
*ops
;
371 const char *transport_name
;
372 struct ltt_channel
*chan
;
376 chan_objd
= objd_alloc(NULL
, <tng_channel_ops
);
381 switch (channel_type
) {
382 case PER_CPU_CHANNEL
:
383 if (chan_param
->output
== LTTNG_UST_MMAP
) {
384 transport_name
= chan_param
->overwrite
?
385 "relay-overwrite-mmap" : "relay-discard-mmap";
389 ops
= <tng_channel_ops
;
391 case METADATA_CHANNEL
:
392 if (chan_param
->output
== LTTNG_UST_MMAP
)
393 transport_name
= "relay-metadata-mmap";
396 ops
= <tng_metadata_ops
;
399 transport_name
= "<unknown>";
403 * We tolerate no failure path after channel creation. It will stay
404 * invariant for the rest of the session.
406 chan
= ltt_channel_create(session
, transport_name
, NULL
,
407 chan_param
->subbuf_size
,
408 chan_param
->num_subbuf
,
409 chan_param
->switch_timer_interval
,
410 chan_param
->read_timer_interval
);
415 objd_set_private(chan_objd
, chan
);
416 chan
->objd
= chan_objd
;
417 if (channel_type
== METADATA_CHANNEL
) {
418 session
->metadata
= chan
;
419 lttng_metadata_create_events(chan_objd
);
422 /* The channel created holds a reference on the session */
423 objd_ref(session_objd
);
431 err
= objd_unref(chan_objd
);
439 * lttng_session_cmd - lttng session object command
445 * This descriptor implements lttng commands:
447 * Returns a LTTng channel object descriptor
449 * Enables tracing for a session (weak enable)
451 * Disables tracing for a session (strong disable)
453 * Returns a LTTng metadata object descriptor
455 * The returned channel will be deleted when its file descriptor is closed.
458 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
460 struct ltt_session
*session
= objd_private(objd
);
463 case LTTNG_UST_CHANNEL
:
464 return lttng_abi_create_channel(objd
,
465 (struct lttng_ust_channel
*) arg
,
467 case LTTNG_UST_SESSION_START
:
468 case LTTNG_UST_ENABLE
:
469 return ltt_session_enable(session
);
470 case LTTNG_UST_SESSION_STOP
:
471 case LTTNG_UST_DISABLE
:
472 return ltt_session_disable(session
);
473 case LTTNG_UST_METADATA
:
474 return lttng_abi_create_channel(objd
,
475 (struct lttng_ust_channel
*) arg
,
483 * Called when the last file reference is dropped.
485 * Big fat note: channels and events are invariant for the whole session after
486 * their creation. So this session destruction also destroys all channel and
487 * event structures specific to this session (they are not destroyed when their
488 * individual file is released).
491 int lttng_release_session(int objd
)
493 struct ltt_session
*session
= objd_private(objd
);
496 ltt_session_destroy(session
);
503 static const struct objd_ops lttng_session_ops
= {
504 .release
= lttng_release_session
,
505 .cmd
= lttng_session_cmd
,
510 int lttng_abi_open_stream(int channel_objd
)
512 struct ltt_channel
*channel
= objd_private(channel_objd
);
513 struct lib_ring_buffer
*buf
;
514 int stream_objd
, ret
;
516 buf
= channel
->ops
->buffer_read_open(channel
->chan
);
520 stream_objd
= objd_alloc(buf
, &lib_ring_buffer_objd_ops
);
521 if (stream_objd
< 0) {
526 * The stream holds a reference to the channel within the generic ring
527 * buffer library, so no need to hold a refcount on the channel and
528 * session files here.
533 channel
->ops
->buffer_read_close(buf
);
539 int lttng_abi_create_event(int channel_objd
,
540 struct lttng_ust_event
*event_param
)
542 struct ltt_channel
*channel
= objd_private(channel_objd
);
543 struct ltt_event
*event
;
546 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
547 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
548 if (event_objd
< 0) {
553 * We tolerate no failure path after event creation. It will stay
554 * invariant for the rest of the session.
556 event
= ltt_event_create(channel
, event_param
, NULL
);
561 objd_set_private(event_objd
, event
);
562 /* The event holds a reference on the channel */
563 objd_ref(channel_objd
);
570 err
= objd_unref(event_objd
);
578 * lttng_channel_cmd - lttng control through object descriptors
580 * @objd: the object descriptor
584 * This object descriptor implements lttng commands:
586 * Returns an event stream object descriptor or failure.
587 * (typically, one event stream records events from one CPU)
589 * Returns an event object descriptor or failure.
591 * Prepend a context field to each event in the channel
593 * Enable recording for events in this channel (weak enable)
595 * Disable recording for events in this channel (strong disable)
597 * Channel and event file descriptors also hold a reference on the session.
600 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
602 struct ltt_channel
*channel
= objd_private(objd
);
605 case LTTNG_UST_STREAM
:
606 return -ENOSYS
; //TODO
607 //return lttng_abi_open_stream(objd);
608 case LTTNG_UST_EVENT
:
609 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
610 case LTTNG_UST_CONTEXT
:
611 return lttng_abi_add_context(objd
,
612 (struct lttng_ust_context
*) arg
,
613 &channel
->ctx
, channel
->session
);
614 case LTTNG_UST_ENABLE
:
615 return ltt_channel_enable(channel
);
616 case LTTNG_UST_DISABLE
:
617 return ltt_channel_disable(channel
);
624 * lttng_metadata_cmd - lttng control through object descriptors
626 * @objd: the object descriptor
630 * This object descriptor implements lttng commands:
632 * Returns an event stream file descriptor or failure.
634 * Channel and event file descriptors also hold a reference on the session.
637 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
640 case LTTNG_UST_STREAM
:
641 return -ENOSYS
; //TODO
642 //return lttng_abi_open_stream(objd);
650 * lttng_channel_poll - lttng stream addition/removal monitoring
655 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
657 struct ltt_channel
*channel
= file
->private_data
;
658 unsigned int mask
= 0;
660 if (file
->f_mode
& FMODE_READ
) {
661 poll_wait_set_exclusive(wait
);
662 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
665 if (channel
->ops
->is_disabled(channel
->chan
))
667 if (channel
->ops
->is_finalized(channel
->chan
))
669 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
670 return POLLIN
| POLLRDNORM
;
679 int lttng_channel_release(int objd
)
681 struct ltt_channel
*channel
= objd_private(objd
);
684 return objd_unref(channel
->session
->objd
);
688 static const struct objd_ops lttng_channel_ops
= {
689 .release
= lttng_channel_release
,
690 //.poll = lttng_channel_poll,
691 .cmd
= lttng_channel_cmd
,
694 static const struct objd_ops lttng_metadata_ops
= {
695 .release
= lttng_channel_release
,
696 .cmd
= lttng_metadata_cmd
,
700 * lttng_event_cmd - lttng control through object descriptors
702 * @objd: the object descriptor
706 * This object descriptor implements lttng commands:
708 * Prepend a context field to each record of this event
710 * Enable recording for this event (weak enable)
712 * Disable recording for this event (strong disable)
715 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
717 struct ltt_event
*event
= objd_private(objd
);
720 case LTTNG_UST_CONTEXT
:
721 return lttng_abi_add_context(objd
,
722 (struct lttng_ust_context
*) arg
,
723 &event
->ctx
, event
->chan
->session
);
724 case LTTNG_UST_ENABLE
:
725 return ltt_event_enable(event
);
726 case LTTNG_UST_DISABLE
:
727 return ltt_event_disable(event
);
734 int lttng_event_release(int objd
)
736 struct ltt_event
*event
= objd_private(objd
);
739 return objd_unref(event
->chan
->objd
);
743 /* TODO: filter control ioctl */
744 static const struct objd_ops lttng_event_ops
= {
745 .release
= lttng_event_release
,
746 .cmd
= lttng_event_cmd
,
749 void lttng_ust_abi_exit(void)
751 objd_table_destroy();