4 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * Mimic system calls for:
9 * - session creation, returns a file descriptor or failure.
10 * - channel creation, returns a file descriptor or failure.
11 * - Operates on a session file descriptor
12 * - Takes all channel options as parameters.
13 * - stream get, returns a file descriptor or failure.
14 * - Operates on a channel file descriptor.
15 * - stream notifier get, returns a file descriptor or failure.
16 * - Operates on a channel file descriptor.
17 * - event creation, returns a file descriptor or failure.
18 * - Operates on a channel file 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 <linux/module.h>
28 #include <linux/debugfs.h>
29 #include <linux/anon_inodes.h>
30 #include <linux/file.h>
31 #include <linux/uaccess.h>
32 #include <linux/slab.h>
33 #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
34 #include "wrapper/ringbuffer/vfs.h"
35 #include "wrapper/poll.h"
36 #include "ltt-debugfs-abi.h"
37 #include "ltt-events.h"
38 #include "ltt-tracer.h"
41 * This is LTTng's own personal way to create a system call as an external
42 * module. We use ioctl() on /sys/kernel/debug/lttng.
45 static struct dentry
*lttng_dentry
;
46 static const struct file_operations lttng_fops
;
47 static const struct file_operations lttng_session_fops
;
48 static const struct file_operations lttng_channel_fops
;
49 static const struct file_operations lttng_metadata_fops
;
50 static const struct file_operations lttng_event_fops
;
58 int lttng_abi_create_session(void)
60 struct ltt_session
*session
;
61 struct file
*session_file
;
64 session
= ltt_session_create();
67 session_fd
= get_unused_fd();
72 session_file
= anon_inode_getfile("[lttng_session]",
75 if (IS_ERR(session_file
)) {
76 ret
= PTR_ERR(session_file
);
79 session
->file
= session_file
;
80 fd_install(session_fd
, session_file
);
84 put_unused_fd(session_fd
);
86 ltt_session_destroy(session
);
91 int lttng_abi_tracepoint_list(void)
93 struct file
*tracepoint_list_file
;
96 file_fd
= get_unused_fd();
102 tracepoint_list_file
= anon_inode_getfile("[lttng_session]",
103 <tng_tracepoint_list_fops
,
105 if (IS_ERR(tracepoint_list_file
)) {
106 ret
= PTR_ERR(tracepoint_list_file
);
109 ret
= lttng_tracepoint_list_fops
.open(NULL
, tracepoint_list_file
);
112 fd_install(file_fd
, tracepoint_list_file
);
120 fput(tracepoint_list_file
);
122 put_unused_fd(file_fd
);
128 long lttng_abi_tracer_version(struct file
*file
,
129 struct lttng_kernel_tracer_version __user
*uversion_param
)
131 struct lttng_kernel_tracer_version v
;
133 v
.version
= LTTNG_VERSION
;
134 v
.patchlevel
= LTTNG_PATCHLEVEL
;
135 v
.sublevel
= LTTNG_SUBLEVEL
;
137 if (copy_to_user(uversion_param
, &v
, sizeof(v
)))
143 long lttng_abi_add_context(struct file
*file
,
144 struct lttng_kernel_context __user
*ucontext_param
,
145 struct lttng_ctx
**ctx
, struct ltt_session
*session
)
147 struct lttng_kernel_context context_param
;
149 if (session
->been_active
)
152 if (copy_from_user(&context_param
, ucontext_param
, sizeof(context_param
)))
155 switch (context_param
.ctx
) {
156 case LTTNG_KERNEL_CONTEXT_PID
:
157 return lttng_add_pid_to_ctx(ctx
);
158 case LTTNG_KERNEL_CONTEXT_PRIO
:
159 return lttng_add_prio_to_ctx(ctx
);
160 case LTTNG_KERNEL_CONTEXT_NICE
:
161 return lttng_add_nice_to_ctx(ctx
);
162 case LTTNG_KERNEL_CONTEXT_VPID
:
163 return lttng_add_vpid_to_ctx(ctx
);
164 case LTTNG_KERNEL_CONTEXT_TID
:
165 return lttng_add_tid_to_ctx(ctx
);
166 case LTTNG_KERNEL_CONTEXT_VTID
:
167 return lttng_add_vtid_to_ctx(ctx
);
168 case LTTNG_KERNEL_CONTEXT_PPID
:
169 return lttng_add_ppid_to_ctx(ctx
);
170 case LTTNG_KERNEL_CONTEXT_VPPID
:
171 return lttng_add_vppid_to_ctx(ctx
);
172 case LTTNG_KERNEL_CONTEXT_PERF_COUNTER
:
173 context_param
.u
.perf_counter
.name
[LTTNG_SYM_NAME_LEN
- 1] = '\0';
174 return lttng_add_perf_counter_to_ctx(context_param
.u
.perf_counter
.type
,
175 context_param
.u
.perf_counter
.config
,
176 context_param
.u
.perf_counter
.name
,
178 case LTTNG_KERNEL_CONTEXT_COMM
:
179 return lttng_add_comm_to_ctx(ctx
);
186 * lttng_ioctl - lttng syscall through ioctl
192 * This ioctl implements lttng commands:
193 * LTTNG_KERNEL_SESSION
194 * Returns a LTTng trace session file descriptor
195 * LTTNG_KERNEL_TRACER_VERSION
196 * Returns the LTTng kernel tracer version
197 * LTTNG_KERNEL_TRACEPOINT_LIST
198 * Returns a file descriptor listing available tracepoints
200 * The returned session will be deleted when its file descriptor is closed.
203 long lttng_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
206 case LTTNG_KERNEL_SESSION
:
207 return lttng_abi_create_session();
208 case LTTNG_KERNEL_TRACER_VERSION
:
209 return lttng_abi_tracer_version(file
,
210 (struct lttng_kernel_tracer_version __user
*) arg
);
211 case LTTNG_KERNEL_TRACEPOINT_LIST
:
212 return lttng_abi_tracepoint_list();
218 static const struct file_operations lttng_fops
= {
219 .unlocked_ioctl
= lttng_ioctl
,
221 .compat_ioctl
= lttng_ioctl
,
226 * We tolerate no failure in this function (if one happens, we print a dmesg
227 * error, but cannot return any error, because the channel information is
231 void lttng_metadata_create_events(struct file
*channel_file
)
233 struct ltt_channel
*channel
= channel_file
->private_data
;
234 static struct lttng_kernel_event metadata_params
= {
235 .instrumentation
= LTTNG_KERNEL_TRACEPOINT
,
236 .name
= "lttng_metadata",
238 struct ltt_event
*event
;
242 * We tolerate no failure path after event creation. It will stay
243 * invariant for the rest of the session.
245 event
= ltt_event_create(channel
, &metadata_params
, NULL
);
254 return; /* not allowed to return error */
258 int lttng_abi_create_channel(struct file
*session_file
,
259 struct lttng_kernel_channel __user
*uchan_param
,
260 enum channel_type channel_type
)
262 struct ltt_session
*session
= session_file
->private_data
;
263 const struct file_operations
*fops
;
264 const char *transport_name
;
265 struct ltt_channel
*chan
;
266 struct file
*chan_file
;
267 struct lttng_kernel_channel chan_param
;
271 if (copy_from_user(&chan_param
, uchan_param
, sizeof(chan_param
)))
273 chan_fd
= get_unused_fd();
278 chan_file
= anon_inode_getfile("[lttng_channel]",
281 if (IS_ERR(chan_file
)) {
282 ret
= PTR_ERR(chan_file
);
285 switch (channel_type
) {
286 case PER_CPU_CHANNEL
:
287 transport_name
= chan_param
.overwrite
?
288 "relay-overwrite" : "relay-discard";
289 fops
= <tng_channel_fops
;
291 case METADATA_CHANNEL
:
292 transport_name
= "relay-metadata";
293 fops
= <tng_metadata_fops
;
296 transport_name
= "<unknown>";
300 * We tolerate no failure path after channel creation. It will stay
301 * invariant for the rest of the session.
303 chan
= ltt_channel_create(session
, transport_name
, NULL
,
304 chan_param
.subbuf_size
,
305 chan_param
.num_subbuf
,
306 chan_param
.switch_timer_interval
,
307 chan_param
.read_timer_interval
);
312 chan
->file
= chan_file
;
313 chan_file
->private_data
= chan
;
314 fd_install(chan_fd
, chan_file
);
315 if (channel_type
== METADATA_CHANNEL
) {
316 session
->metadata
= chan
;
317 lttng_metadata_create_events(chan_file
);
320 /* The channel created holds a reference on the session */
321 atomic_long_inc(&session_file
->f_count
);
328 put_unused_fd(chan_fd
);
334 * lttng_session_ioctl - lttng session fd ioctl
340 * This ioctl implements lttng commands:
341 * LTTNG_KERNEL_CHANNEL
342 * Returns a LTTng channel file descriptor
343 * LTTNG_KERNEL_ENABLE
344 * Enables tracing for a session (weak enable)
345 * LTTNG_KERNEL_DISABLE
346 * Disables tracing for a session (strong disable)
347 * LTTNG_KERNEL_METADATA
348 * Returns a LTTng metadata file descriptor
350 * The returned channel will be deleted when its file descriptor is closed.
353 long lttng_session_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
355 struct ltt_session
*session
= file
->private_data
;
358 case LTTNG_KERNEL_CHANNEL
:
359 return lttng_abi_create_channel(file
,
360 (struct lttng_kernel_channel __user
*) arg
,
362 case LTTNG_KERNEL_SESSION_START
:
363 case LTTNG_KERNEL_ENABLE
:
364 return ltt_session_enable(session
);
365 case LTTNG_KERNEL_SESSION_STOP
:
366 case LTTNG_KERNEL_DISABLE
:
367 return ltt_session_disable(session
);
368 case LTTNG_KERNEL_METADATA
:
369 return lttng_abi_create_channel(file
,
370 (struct lttng_kernel_channel __user
*) arg
,
378 * Called when the last file reference is dropped.
380 * Big fat note: channels and events are invariant for the whole session after
381 * their creation. So this session destruction also destroys all channel and
382 * event structures specific to this session (they are not destroyed when their
383 * individual file is released).
386 int lttng_session_release(struct inode
*inode
, struct file
*file
)
388 struct ltt_session
*session
= file
->private_data
;
391 ltt_session_destroy(session
);
395 static const struct file_operations lttng_session_fops
= {
396 .release
= lttng_session_release
,
397 .unlocked_ioctl
= lttng_session_ioctl
,
399 .compat_ioctl
= lttng_session_ioctl
,
404 int lttng_abi_open_stream(struct file
*channel_file
)
406 struct ltt_channel
*channel
= channel_file
->private_data
;
407 struct lib_ring_buffer
*buf
;
409 struct file
*stream_file
;
411 buf
= channel
->ops
->buffer_read_open(channel
->chan
);
415 stream_fd
= get_unused_fd();
420 stream_file
= anon_inode_getfile("[lttng_stream]",
421 &lib_ring_buffer_file_operations
,
423 if (IS_ERR(stream_file
)) {
424 ret
= PTR_ERR(stream_file
);
428 * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
429 * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
430 * file descriptor, so we set FMODE_PREAD here.
432 stream_file
->f_mode
|= FMODE_PREAD
;
433 fd_install(stream_fd
, stream_file
);
435 * The stream holds a reference to the channel within the generic ring
436 * buffer library, so no need to hold a refcount on the channel and
437 * session files here.
442 put_unused_fd(stream_fd
);
444 channel
->ops
->buffer_read_close(buf
);
449 int lttng_abi_create_event(struct file
*channel_file
,
450 struct lttng_kernel_event __user
*uevent_param
)
452 struct ltt_channel
*channel
= channel_file
->private_data
;
453 struct ltt_event
*event
;
454 struct lttng_kernel_event event_param
;
456 struct file
*event_file
;
458 if (copy_from_user(&event_param
, uevent_param
, sizeof(event_param
)))
460 event_param
.name
[LTTNG_SYM_NAME_LEN
- 1] = '\0';
461 switch (event_param
.instrumentation
) {
462 case LTTNG_KERNEL_KPROBE
:
463 event_param
.u
.kprobe
.symbol_name
[LTTNG_SYM_NAME_LEN
- 1] = '\0';
465 case LTTNG_KERNEL_FUNCTION
:
466 event_param
.u
.ftrace
.symbol_name
[LTTNG_SYM_NAME_LEN
- 1] = '\0';
471 event_fd
= get_unused_fd();
476 event_file
= anon_inode_getfile("[lttng_event]",
479 if (IS_ERR(event_file
)) {
480 ret
= PTR_ERR(event_file
);
484 * We tolerate no failure path after event creation. It will stay
485 * invariant for the rest of the session.
487 event
= ltt_event_create(channel
, &event_param
, NULL
);
492 event_file
->private_data
= event
;
493 fd_install(event_fd
, event_file
);
494 /* The event holds a reference on the channel */
495 atomic_long_inc(&channel_file
->f_count
);
501 put_unused_fd(event_fd
);
507 * lttng_channel_ioctl - lttng syscall through ioctl
513 * This ioctl implements lttng commands:
514 * LTTNG_KERNEL_STREAM
515 * Returns an event stream file descriptor or failure.
516 * (typically, one event stream records events from one CPU)
518 * Returns an event file descriptor or failure.
519 * LTTNG_KERNEL_CONTEXT
520 * Prepend a context field to each event in the channel
521 * LTTNG_KERNEL_ENABLE
522 * Enable recording for events in this channel (weak enable)
523 * LTTNG_KERNEL_DISABLE
524 * Disable recording for events in this channel (strong disable)
526 * Channel and event file descriptors also hold a reference on the session.
529 long lttng_channel_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
531 struct ltt_channel
*channel
= file
->private_data
;
534 case LTTNG_KERNEL_STREAM
:
535 return lttng_abi_open_stream(file
);
536 case LTTNG_KERNEL_EVENT
:
537 return lttng_abi_create_event(file
, (struct lttng_kernel_event __user
*) arg
);
538 case LTTNG_KERNEL_CONTEXT
:
539 return lttng_abi_add_context(file
,
540 (struct lttng_kernel_context __user
*) arg
,
541 &channel
->ctx
, channel
->session
);
542 case LTTNG_KERNEL_ENABLE
:
543 return ltt_channel_enable(channel
);
544 case LTTNG_KERNEL_DISABLE
:
545 return ltt_channel_disable(channel
);
552 * lttng_metadata_ioctl - lttng syscall through ioctl
558 * This ioctl implements lttng commands:
559 * LTTNG_KERNEL_STREAM
560 * Returns an event stream file descriptor or failure.
562 * Channel and event file descriptors also hold a reference on the session.
565 long lttng_metadata_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
568 case LTTNG_KERNEL_STREAM
:
569 return lttng_abi_open_stream(file
);
576 * lttng_channel_poll - lttng stream addition/removal monitoring
581 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
583 struct ltt_channel
*channel
= file
->private_data
;
584 unsigned int mask
= 0;
586 if (file
->f_mode
& FMODE_READ
) {
587 poll_wait_set_exclusive(wait
);
588 poll_wait(file
, channel
->ops
->get_hp_wait_queue(channel
->chan
),
591 if (channel
->ops
->is_disabled(channel
->chan
))
593 if (channel
->ops
->is_finalized(channel
->chan
))
596 return POLLIN
| POLLRDNORM
;
603 int lttng_channel_release(struct inode
*inode
, struct file
*file
)
605 struct ltt_channel
*channel
= file
->private_data
;
608 fput(channel
->session
->file
);
612 static const struct file_operations lttng_channel_fops
= {
613 .release
= lttng_channel_release
,
614 .poll
= lttng_channel_poll
,
615 .unlocked_ioctl
= lttng_channel_ioctl
,
617 .compat_ioctl
= lttng_channel_ioctl
,
621 static const struct file_operations lttng_metadata_fops
= {
622 .release
= lttng_channel_release
,
623 .unlocked_ioctl
= lttng_metadata_ioctl
,
625 .compat_ioctl
= lttng_metadata_ioctl
,
630 * lttng_event_ioctl - lttng syscall through ioctl
636 * This ioctl implements lttng commands:
637 * LTTNG_KERNEL_CONTEXT
638 * Prepend a context field to each record of this event
639 * LTTNG_KERNEL_ENABLE
640 * Enable recording for this event (weak enable)
641 * LTTNG_KERNEL_DISABLE
642 * Disable recording for this event (strong disable)
645 long lttng_event_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
647 struct ltt_event
*event
= file
->private_data
;
650 case LTTNG_KERNEL_CONTEXT
:
651 return lttng_abi_add_context(file
,
652 (struct lttng_kernel_context __user
*) arg
,
653 &event
->ctx
, event
->chan
->session
);
654 case LTTNG_KERNEL_ENABLE
:
655 return ltt_event_enable(event
);
656 case LTTNG_KERNEL_DISABLE
:
657 return ltt_event_disable(event
);
664 int lttng_event_release(struct inode
*inode
, struct file
*file
)
666 struct ltt_event
*event
= file
->private_data
;
669 fput(event
->chan
->file
);
673 /* TODO: filter control ioctl */
674 static const struct file_operations lttng_event_fops
= {
675 .release
= lttng_event_release
,
676 .unlocked_ioctl
= lttng_event_ioctl
,
678 .compat_ioctl
= lttng_event_ioctl
,
682 int __init
ltt_debugfs_abi_init(void)
686 wrapper_vmalloc_sync_all();
687 lttng_dentry
= debugfs_create_file("lttng", S_IWUSR
, NULL
, NULL
,
689 if (IS_ERR(lttng_dentry
) || !lttng_dentry
) {
690 printk(KERN_ERR
"Error creating LTTng control file\n");
698 void __exit
ltt_debugfs_abi_exit(void)
700 debugfs_remove(lttng_dentry
);