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
);
194 * This is LTTng's own personal way to create an ABI for sessiond.
195 * We send commands over a socket.
198 static const struct objd_ops lttng_ops
;
199 static const struct objd_ops lttng_session_ops
;
200 static const struct objd_ops lttng_channel_ops
;
201 static const struct objd_ops lttng_metadata_ops
;
202 static const struct objd_ops lttng_event_ops
;
209 int lttng_abi_create_root_handle(void)
213 root_handle
= objd_alloc(NULL
, <tng_ops
);
214 assert(root_handle
== 0);
219 int lttng_abi_create_session(void)
221 struct ltt_session
*session
;
222 int session_objd
, ret
;
224 session
= ltt_session_create();
227 session_objd
= objd_alloc(session
, <tng_session_ops
);
228 if (session_objd
< 0) {
232 session
->objd
= session_objd
;
236 ltt_session_destroy(session
);
242 int lttng_abi_tracepoint_list(void)
246 /* TODO: Create list private data */
247 list_objd
= objd_alloc(NULL
, <tng_tracepoint_list_ops
);
261 long lttng_abi_tracer_version(int objd
,
262 struct lttng_ust_tracer_version
*v
)
264 v
->version
= LTTNG_UST_VERSION
;
265 v
->patchlevel
= LTTNG_UST_PATCHLEVEL
;
266 v
->sublevel
= LTTNG_UST_SUBLEVEL
;
271 long lttng_abi_add_context(int objd
,
272 struct lttng_ust_context
*context_param
,
273 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
275 if (session
->been_active
)
278 switch (context_param
->ctx
) {
279 case LTTNG_UST_CONTEXT_VTID
:
280 //TODO return lttng_add_vtid_to_ctx(ctx);
287 * lttng_cmd - lttng control through socket commands
289 * @objd: the object descriptor
293 * This descriptor implements lttng commands:
295 * Returns a LTTng trace session object descriptor
296 * LTTNG_UST_TRACER_VERSION
297 * Returns the LTTng kernel tracer version
298 * LTTNG_UST_TRACEPOINT_LIST
299 * Returns a file descriptor listing available tracepoints
300 * LTTNG_UST_WAIT_QUIESCENT
301 * Returns after all previously running probes have completed
303 * The returned session will be deleted when its file descriptor is closed.
306 long lttng_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
309 case LTTNG_UST_SESSION
:
310 return lttng_abi_create_session();
311 case LTTNG_UST_TRACER_VERSION
:
312 return lttng_abi_tracer_version(objd
,
313 (struct lttng_ust_tracer_version
*) arg
);
314 case LTTNG_UST_TRACEPOINT_LIST
:
315 return -ENOSYS
; //TODO
316 //return lttng_abi_tracepoint_list();
317 case LTTNG_UST_WAIT_QUIESCENT
:
325 static const struct objd_ops lttng_ops
= {
330 * We tolerate no failure in this function (if one happens, we print a dmesg
331 * error, but cannot return any error, because the channel information is
335 void lttng_metadata_create_events(int channel_objd
)
337 struct ltt_channel
*channel
= objd_private(channel_objd
);
338 static struct lttng_ust_event metadata_params
= {
339 .instrumentation
= LTTNG_UST_TRACEPOINT
,
340 .name
= "lttng_metadata",
342 struct ltt_event
*event
;
346 * We tolerate no failure path after event creation. It will stay
347 * invariant for the rest of the session.
349 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
358 return; /* not allowed to return error */
361 int lttng_abi_create_channel(int session_objd
,
362 struct lttng_ust_channel
*chan_param
,
363 enum channel_type channel_type
)
365 struct ltt_session
*session
= objd_private(session_objd
);
366 const struct objd_ops
*ops
;
367 const char *transport_name
;
368 struct ltt_channel
*chan
;
372 chan_objd
= objd_alloc(NULL
, <tng_channel_ops
);
377 switch (channel_type
) {
378 case PER_CPU_CHANNEL
:
379 if (chan_param
->output
== LTTNG_UST_MMAP
) {
380 transport_name
= chan_param
->overwrite
?
381 "relay-overwrite-mmap" : "relay-discard-mmap";
385 ops
= <tng_channel_ops
;
387 case METADATA_CHANNEL
:
388 if (chan_param
->output
== LTTNG_UST_MMAP
)
389 transport_name
= "relay-metadata-mmap";
392 ops
= <tng_metadata_ops
;
395 transport_name
= "<unknown>";
399 * We tolerate no failure path after channel creation. It will stay
400 * invariant for the rest of the session.
402 chan
= ltt_channel_create(session
, transport_name
, NULL
,
403 chan_param
->subbuf_size
,
404 chan_param
->num_subbuf
,
405 chan_param
->switch_timer_interval
,
406 chan_param
->read_timer_interval
);
411 objd_set_private(chan_objd
, chan
);
412 chan
->objd
= chan_objd
;
413 if (channel_type
== METADATA_CHANNEL
) {
414 session
->metadata
= chan
;
415 lttng_metadata_create_events(chan_objd
);
418 /* The channel created holds a reference on the session */
419 objd_ref(session_objd
);
427 err
= objd_unref(chan_objd
);
435 * lttng_session_cmd - lttng session object command
441 * This descriptor implements lttng commands:
443 * Returns a LTTng channel object descriptor
445 * Enables tracing for a session (weak enable)
447 * Disables tracing for a session (strong disable)
449 * Returns a LTTng metadata object descriptor
451 * The returned channel will be deleted when its file descriptor is closed.
454 long lttng_session_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
456 struct ltt_session
*session
= objd_private(objd
);
459 case LTTNG_UST_CHANNEL
:
460 return lttng_abi_create_channel(objd
,
461 (struct lttng_ust_channel
*) arg
,
463 case LTTNG_UST_SESSION_START
:
464 case LTTNG_UST_ENABLE
:
465 return ltt_session_enable(session
);
466 case LTTNG_UST_SESSION_STOP
:
467 case LTTNG_UST_DISABLE
:
468 return ltt_session_disable(session
);
469 case LTTNG_UST_METADATA
:
470 return lttng_abi_create_channel(objd
,
471 (struct lttng_ust_channel
*) arg
,
479 * Called when the last file reference is dropped.
481 * Big fat note: channels and events are invariant for the whole session after
482 * their creation. So this session destruction also destroys all channel and
483 * event structures specific to this session (they are not destroyed when their
484 * individual file is released).
487 int lttng_release_session(int objd
)
489 struct ltt_session
*session
= objd_private(objd
);
492 ltt_session_destroy(session
);
499 static const struct objd_ops lttng_session_ops
= {
500 .release
= lttng_release_session
,
501 .cmd
= lttng_session_cmd
,
506 int lttng_abi_open_stream(int channel_objd
)
508 struct ltt_channel
*channel
= objd_private(channel_objd
);
509 struct lib_ring_buffer
*buf
;
510 int stream_objd
, ret
;
512 buf
= channel
->ops
->buffer_read_open(channel
->chan
);
516 stream_objd
= objd_alloc(buf
, &lib_ring_buffer_objd_ops
);
517 if (stream_objd
< 0) {
522 * The stream holds a reference to the channel within the generic ring
523 * buffer library, so no need to hold a refcount on the channel and
524 * session files here.
529 channel
->ops
->buffer_read_close(buf
);
535 int lttng_abi_create_event(int channel_objd
,
536 struct lttng_ust_event
*event_param
)
538 struct ltt_channel
*channel
= objd_private(channel_objd
);
539 struct ltt_event
*event
;
542 event_param
->name
[LTTNG_UST_SYM_NAME_LEN
- 1] = '\0';
543 event_objd
= objd_alloc(NULL
, <tng_event_ops
);
544 if (event_objd
< 0) {
549 * We tolerate no failure path after event creation. It will stay
550 * invariant for the rest of the session.
552 event
= ltt_event_create(channel
, event_param
, NULL
);
557 objd_set_private(event_objd
, event
);
558 /* The event holds a reference on the channel */
559 objd_ref(channel_objd
);
566 err
= objd_unref(event_objd
);
574 * lttng_channel_cmd - lttng control through object descriptors
576 * @objd: the object descriptor
580 * This object descriptor implements lttng commands:
582 * Returns an event stream object descriptor or failure.
583 * (typically, one event stream records events from one CPU)
585 * Returns an event object descriptor or failure.
587 * Prepend a context field to each event in the channel
589 * Enable recording for events in this channel (weak enable)
591 * Disable recording for events in this channel (strong disable)
593 * Channel and event file descriptors also hold a reference on the session.
596 long lttng_channel_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
598 struct ltt_channel
*channel
= objd_private(objd
);
601 case LTTNG_UST_STREAM
:
602 return -ENOSYS
; //TODO
603 //return lttng_abi_open_stream(objd);
604 case LTTNG_UST_EVENT
:
605 return lttng_abi_create_event(objd
, (struct lttng_ust_event
*) arg
);
606 case LTTNG_UST_CONTEXT
:
607 return lttng_abi_add_context(objd
,
608 (struct lttng_ust_context
*) arg
,
609 &channel
->ctx
, channel
->session
);
610 case LTTNG_UST_ENABLE
:
611 return ltt_channel_enable(channel
);
612 case LTTNG_UST_DISABLE
:
613 return ltt_channel_disable(channel
);
620 * lttng_metadata_cmd - lttng control through object descriptors
622 * @objd: the object descriptor
626 * This object descriptor implements lttng commands:
628 * Returns an event stream file descriptor or failure.
630 * Channel and event file descriptors also hold a reference on the session.
633 long lttng_metadata_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
636 case LTTNG_UST_STREAM
:
637 return -ENOSYS
; //TODO
638 //return lttng_abi_open_stream(objd);
646 * lttng_channel_poll - lttng stream addition/removal monitoring
651 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
653 struct ltt_channel
*channel
= file
->private_data
;
654 unsigned int mask
= 0;
656 if (file
->f_mode
& FMODE_READ
) {
657 poll_wait_set_exclusive(wait
);
658 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
661 if (channel
->ops
->is_disabled(channel
->chan
))
663 if (channel
->ops
->is_finalized(channel
->chan
))
665 if (channel
->ops
->buffer_has_read_closed_stream(channel
->chan
))
666 return POLLIN
| POLLRDNORM
;
675 int lttng_channel_release(int objd
)
677 struct ltt_channel
*channel
= objd_private(objd
);
680 return objd_unref(channel
->session
->objd
);
684 static const struct objd_ops lttng_channel_ops
= {
685 .release
= lttng_channel_release
,
686 //.poll = lttng_channel_poll,
687 .cmd
= lttng_channel_cmd
,
690 static const struct objd_ops lttng_metadata_ops
= {
691 .release
= lttng_channel_release
,
692 .cmd
= lttng_metadata_cmd
,
696 * lttng_event_cmd - lttng control through object descriptors
698 * @objd: the object descriptor
702 * This object descriptor implements lttng commands:
704 * Prepend a context field to each record of this event
706 * Enable recording for this event (weak enable)
708 * Disable recording for this event (strong disable)
711 long lttng_event_cmd(int objd
, unsigned int cmd
, unsigned long arg
)
713 struct ltt_event
*event
= objd_private(objd
);
716 case LTTNG_UST_CONTEXT
:
717 return lttng_abi_add_context(objd
,
718 (struct lttng_ust_context
*) arg
,
719 &event
->ctx
, event
->chan
->session
);
720 case LTTNG_UST_ENABLE
:
721 return ltt_event_enable(event
);
722 case LTTNG_UST_DISABLE
:
723 return ltt_event_disable(event
);
730 int lttng_event_release(int objd
)
732 struct ltt_event
*event
= objd_private(objd
);
735 return objd_unref(event
->chan
->objd
);
739 /* TODO: filter control ioctl */
740 static const struct objd_ops lttng_event_ops
= {
741 .release
= lttng_event_release
,
742 .cmd
= lttng_event_cmd
,
745 void lttng_ust_abi_exit(void)
747 objd_table_destroy();