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
= 2; /* count == 1 : object is allocated */
104 /* count == 2 : allocated + hold ref */
105 return obj
- objd_table
.array
;
109 struct 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 obj
*obj
= _objd_get(id
);
123 return obj
->u
.s
.private_data
;
127 void objd_set_private(int id
, void *private_data
)
129 struct obj
*obj
= _objd_get(id
);
131 obj
->u
.s
.private_data
= private_data
;
135 const struct objd_ops
*objd_ops(int id
)
137 struct obj
*obj
= _objd_get(id
);
144 void objd_free(int id
)
146 struct 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 obj
*obj
= _objd_get(id
);
162 int objd_unref(int id
)
164 struct 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 objd_ops
*ops
= objd_ops(id
);
183 void objd_table_destroy(void)
187 for (i
= 0; i
< objd_table
.allocated_len
; i
++) {
188 struct obj
*obj
= _objd_get(i
);
189 const struct objd_ops
*ops
;
197 free(objd_table
.array
);
201 * This is LTTng's own personal way to create an ABI for sessiond.
202 * We send commands over a socket.
205 static const struct objd_ops lttng_ops
;
206 static const struct objd_ops lttng_session_ops
;
207 static const struct objd_ops lttng_channel_ops
;
208 static const struct objd_ops lttng_metadata_ops
;
209 static const struct objd_ops lttng_event_ops
;
216 int lttng_abi_create_session(void)
218 struct ltt_session
*session
;
219 int session_objd
, ret
;
221 session
= ltt_session_create();
224 session_objd
= objd_alloc(session
, <tng_session_ops
);
225 if (session_objd
< 0) {
229 session
->objd
= session_objd
;
233 ltt_session_destroy(session
);
239 int lttng_abi_tracepoint_list(void)
243 /* TODO: Create list private data */
244 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
258 long lttng_abi_tracer_version(int objd
,
259 struct lttng_ust_tracer_version
*v
)
261 v
->version
= LTTNG_UST_VERSION
;
262 v
->patchlevel
= LTTNG_UST_PATCHLEVEL
;
263 v
->sublevel
= LTTNG_UST_SUBLEVEL
;
268 long lttng_abi_add_context(int objd
,
269 struct lttng_ust_context
*context_param
,
270 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
272 if (session
->been_active
)
275 switch (context_param
->ctx
) {
276 case LTTNG_UST_CONTEXT_VTID
:
277 //TODO return lttng_add_vtid_to_ctx(ctx);
284 * lttng_cmd - lttng control through socket commands
286 * @objd: the object descriptor
290 * This descriptor implements lttng commands:
292 * Returns a LTTng trace session object descriptor
293 * LTTNG_UST_TRACER_VERSION
294 * Returns the LTTng kernel tracer version
295 * LTTNG_UST_TRACEPOINT_LIST
296 * Returns a file descriptor listing available tracepoints
297 * LTTNG_UST_WAIT_QUIESCENT
298 * Returns after all previously running probes have completed
300 * The returned session will be deleted when its file descriptor is closed.
303 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
306 case LTTNG_UST_SESSION
:
307 return lttng_abi_create_session();
308 case LTTNG_UST_TRACER_VERSION
:
309 return lttng_abi_tracer_version(objd
,
310 (struct lttng_ust_tracer_version
*) arg
);
311 case LTTNG_UST_TRACEPOINT_LIST
:
312 return -ENOSYS
; //TODO
313 //return lttng_abi_tracepoint_list();
314 case LTTNG_UST_WAIT_QUIESCENT
:
322 static const struct objd_ops lttng_ops
= {
327 * We tolerate no failure in this function (if one happens, we print a dmesg
328 * error, but cannot return any error, because the channel information is
332 void lttng_metadata_create_events(int channel_objd
)
334 struct ltt_channel
*channel
= objd_private(channel_objd
);
335 static struct lttng_ust_event metadata_params
= {
336 .instrumentation
= LTTNG_UST_TRACEPOINT
,
337 .name
= "lttng_metadata",
339 struct ltt_event
*event
;
343 * We tolerate no failure path after event creation. It will stay
344 * invariant for the rest of the session.
346 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
355 return; /* not allowed to return error */
359 int lttng_abi_create_channel(int session_objd
,
360 struct lttng_ust_channel
*chan_param
,
361 enum channel_type channel_type
)
363 struct ltt_session
*session
= objd_private(session_objd
);
364 const struct objd_ops
*ops
;
365 const char *transport_name
;
366 struct ltt_channel
*chan
;
370 chan_objd
= objd_alloc(NULL
, <tng_channel_ops
);
375 switch (channel_type
) {
376 case PER_CPU_CHANNEL
:
377 if (chan_param
->output
== LTTNG_UST_MMAP
) {
378 transport_name
= chan_param
->overwrite
?
379 "relay-overwrite-mmap" : "relay-discard-mmap";
383 ops
= <tng_channel_ops
;
385 case METADATA_CHANNEL
:
386 if (chan_param
->output
== LTTNG_UST_MMAP
)
387 transport_name
= "relay-metadata-mmap";
390 ops
= <tng_metadata_ops
;
393 transport_name
= "<unknown>";
397 * We tolerate no failure path after channel creation. It will stay
398 * invariant for the rest of the session.
400 chan
= ltt_channel_create(session
, transport_name
, NULL
,
401 chan_param
->subbuf_size
,
402 chan_param
->num_subbuf
,
403 chan_param
->switch_timer_interval
,
404 chan_param
->read_timer_interval
);
409 objd_set_private(chan_objd
, chan
);
410 chan
->objd
= chan_objd
;
411 if (channel_type
== METADATA_CHANNEL
) {
412 session
->metadata
= chan
;
413 lttng_metadata_create_events(chan_objd
);
416 /* The channel created holds a reference on the session */
417 objd_ref(session_objd
);
425 err
= objd_unref(chan_objd
);
433 * lttng_session_cmd - lttng session object command
439 * This descriptor implements lttng commands:
441 * Returns a LTTng channel object descriptor
443 * Enables tracing for a session (weak enable)
445 * Disables tracing for a session (strong disable)
447 * Returns a LTTng metadata object descriptor
449 * The returned channel will be deleted when its file descriptor is closed.
452 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
454 struct ltt_session
*session
= objd_private(objd
);
457 case LTTNG_UST_CHANNEL
:
458 return lttng_abi_create_channel(objd
,
459 (struct lttng_ust_channel
*) arg
,
461 case LTTNG_UST_SESSION_START
:
462 case LTTNG_UST_ENABLE
:
463 return ltt_session_enable(session
);
464 case LTTNG_UST_SESSION_STOP
:
465 case LTTNG_UST_DISABLE
:
466 return ltt_session_disable(session
);
467 case LTTNG_UST_METADATA
:
468 return lttng_abi_create_channel(objd
,
469 (struct lttng_ust_channel
*) arg
,
477 * Called when the last file reference is dropped.
479 * Big fat note: channels and events are invariant for the whole session after
480 * their creation. So this session destruction also destroys all channel and
481 * event structures specific to this session (they are not destroyed when their
482 * individual file is released).
485 int lttng_release_session(int objd
)
487 struct ltt_session
*session
= objd_private(objd
);
490 ltt_session_destroy(session
);
497 static const struct objd_ops lttng_session_ops
= {
498 .release
= lttng_release_session
,
499 .cmd
= lttng_session_cmd
,
504 int lttng_abi_open_stream(int channel_objd
)
506 struct ltt_channel
*channel
= objd_private(channel_objd
);
507 struct lib_ring_buffer
*buf
;
508 int stream_objd
, ret
;
510 buf
= channel
->ops
->buffer_read_open(channel
->chan
);
514 stream_objd
= objd_alloc(buf
, &lib_ring_buffer_objd_ops
);
515 if (stream_objd
< 0) {
520 * The stream holds a reference to the channel within the generic ring
521 * buffer library, so no need to hold a refcount on the channel and
522 * session files here.
527 channel
->ops
->buffer_read_close(buf
);
533 int lttng_abi_create_event(int channel_objd
,
534 struct lttng_ust_event
*event_param
)
536 struct ltt_channel
*channel
= objd_private(channel_objd
);
537 struct ltt_event
*event
;
540 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
541 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
542 if (event_objd
< 0) {
547 * We tolerate no failure path after event creation. It will stay
548 * invariant for the rest of the session.
550 event
= ltt_event_create(channel
, event_param
, NULL
);
555 objd_set_private(event_objd
, event
);
556 /* The event holds a reference on the channel */
557 objd_ref(channel_objd
);
564 err
= objd_unref(event_objd
);
572 * lttng_channel_cmd - lttng control through object descriptors
574 * @objd: the object descriptor
578 * This object descriptor implements lttng commands:
580 * Returns an event stream object descriptor or failure.
581 * (typically, one event stream records events from one CPU)
583 * Returns an event object descriptor or failure.
585 * Prepend a context field to each event in the channel
587 * Enable recording for events in this channel (weak enable)
589 * Disable recording for events in this channel (strong disable)
591 * Channel and event file descriptors also hold a reference on the session.
594 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
596 struct ltt_channel
*channel
= objd_private(objd
);
599 case LTTNG_UST_STREAM
:
600 return -ENOSYS
; //TODO
601 //return lttng_abi_open_stream(objd);
602 case LTTNG_UST_EVENT
:
603 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
604 case LTTNG_UST_CONTEXT
:
605 return lttng_abi_add_context(objd
,
606 (struct lttng_ust_context
*) arg
,
607 &channel
->ctx
, channel
->session
);
608 case LTTNG_UST_ENABLE
:
609 return ltt_channel_enable(channel
);
610 case LTTNG_UST_DISABLE
:
611 return ltt_channel_disable(channel
);
618 * lttng_metadata_cmd - lttng control through object descriptors
620 * @objd: the object descriptor
624 * This object descriptor implements lttng commands:
626 * Returns an event stream file descriptor or failure.
628 * Channel and event file descriptors also hold a reference on the session.
631 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
634 case LTTNG_UST_STREAM
:
635 return -ENOSYS
; //TODO
636 //return lttng_abi_open_stream(objd);
644 * lttng_channel_poll - lttng stream addition/removal monitoring
649 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
651 struct ltt_channel
*channel
= file
->private_data
;
652 unsigned int mask
= 0;
654 if (file
->f_mode
& FMODE_READ
) {
655 poll_wait_set_exclusive(wait
);
656 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
659 if (channel
->ops
->is_disabled(channel
->chan
))
661 if (channel
->ops
->is_finalized(channel
->chan
))
663 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
664 return POLLIN
| POLLRDNORM
;
673 int lttng_channel_release(int objd
)
675 struct ltt_channel
*channel
= objd_private(objd
);
678 return objd_unref(channel
->session
->objd
);
682 static const struct objd_ops lttng_channel_ops
= {
683 .release
= lttng_channel_release
,
684 //.poll = lttng_channel_poll,
685 .cmd
= lttng_channel_cmd
,
688 static const struct objd_ops lttng_metadata_ops
= {
689 .release
= lttng_channel_release
,
690 .cmd
= lttng_metadata_cmd
,
694 * lttng_event_cmd - lttng control through object descriptors
696 * @objd: the object descriptor
700 * This object descriptor implements lttng commands:
702 * Prepend a context field to each record of this event
704 * Enable recording for this event (weak enable)
706 * Disable recording for this event (strong disable)
709 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
711 struct ltt_event
*event
= objd_private(objd
);
714 case LTTNG_UST_CONTEXT
:
715 return lttng_abi_add_context(objd
,
716 (struct lttng_ust_context
*) arg
,
717 &event
->ctx
, event
->chan
->session
);
718 case LTTNG_UST_ENABLE
:
719 return ltt_event_enable(event
);
720 case LTTNG_UST_DISABLE
:
721 return ltt_event_disable(event
);
728 int lttng_event_release(int objd
)
730 struct ltt_event
*event
= objd_private(objd
);
733 return objd_unref(event
->chan
->objd
);
737 /* TODO: filter control ioctl */
738 static const struct objd_ops lttng_event_ops
= {
739 .release
= lttng_event_release
,
740 .cmd
= lttng_event_cmd
,
743 void lttng_ust_abi_exit(void)
745 objd_table_destroy();