6 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Mimic system calls for:
24 * - session creation, returns a file descriptor or failure.
25 * - channel creation, returns a file descriptor or failure.
26 * - Operates on a session file descriptor
27 * - Takes all channel options as parameters.
28 * - stream get, returns a file descriptor or failure.
29 * - Operates on a channel file descriptor.
30 * - stream notifier get, returns a file descriptor or failure.
31 * - Operates on a channel file descriptor.
32 * - event creation, returns a file descriptor or failure.
33 * - Operates on a channel file descriptor
34 * - Takes an event name as parameter
35 * - Takes an instrumentation source as parameter
36 * - e.g. tracepoints, dynamic_probes...
37 * - Takes instrumentation source specific arguments.
40 #include <linux/module.h>
41 #include <linux/proc_fs.h>
42 #include <linux/anon_inodes.h>
43 #include <linux/file.h>
44 #include <linux/uaccess.h>
45 #include <linux/slab.h>
46 #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
47 #include "wrapper/ringbuffer/vfs.h"
48 #include "wrapper/poll.h"
49 #include "lttng-abi.h"
50 #include "lttng-events.h"
51 #include "lttng-tracer.h"
54 * This is LTTng's own personal way to create a system call as an external
55 * module. We use ioctl() on /proc/lttng.
58 static struct proc_dir_entry
*lttng_proc_dentry
;
59 static const struct file_operations lttng_fops
;
60 static const struct file_operations lttng_session_fops
;
61 static const struct file_operations lttng_channel_fops
;
62 static const struct file_operations lttng_metadata_fops
;
63 static const struct file_operations lttng_event_fops
;
66 * Teardown management: opened file descriptors keep a refcount on the module,
67 * so it can only exit when all file descriptors are closed.
76 int lttng_abi_create_session(void)
78 struct lttng_session
*session
;
79 struct file
*session_file
;
82 session
= lttng_session_create();
85 session_fd
= get_unused_fd();
90 session_file
= anon_inode_getfile("[lttng_session]",
93 if (IS_ERR(session_file
)) {
94 ret
= PTR_ERR(session_file
);
97 session
->file
= session_file
;
98 fd_install(session_fd
, session_file
);
102 put_unused_fd(session_fd
);
104 lttng_session_destroy(session
);
109 int lttng_abi_tracepoint_list(void)
111 struct file
*tracepoint_list_file
;
114 file_fd
= get_unused_fd();
120 tracepoint_list_file
= anon_inode_getfile("[lttng_session]",
121 <tng_tracepoint_list_fops
,
123 if (IS_ERR(tracepoint_list_file
)) {
124 ret
= PTR_ERR(tracepoint_list_file
);
127 ret
= lttng_tracepoint_list_fops
.open(NULL
, tracepoint_list_file
);
130 fd_install(file_fd
, tracepoint_list_file
);
138 fput(tracepoint_list_file
);
140 put_unused_fd(file_fd
);
146 long lttng_abi_tracer_version(struct file
*file
,
147 struct lttng_kernel_tracer_version __user
*uversion_param
)
149 struct lttng_kernel_tracer_version v
;
151 v
.major
= LTTNG_MODULES_MAJOR_VERSION
;
152 v
.minor
= LTTNG_MODULES_MINOR_VERSION
;
153 v
.patchlevel
= LTTNG_MODULES_PATCHLEVEL_VERSION
;
155 if (copy_to_user(uversion_param
, &v
, sizeof(v
)))
161 long lttng_abi_add_context(struct file
*file
,
162 struct lttng_kernel_context __user
*ucontext_param
,
163 struct lttng_ctx
**ctx
, struct lttng_session
*session
)
165 struct lttng_kernel_context context_param
;
167 if (session
->been_active
)
170 if (copy_from_user(&context_param
, ucontext_param
, sizeof(context_param
)))
173 switch (context_param
.ctx
) {
174 case LTTNG_KERNEL_CONTEXT_PID
:
175 return lttng_add_pid_to_ctx(ctx
);
176 case LTTNG_KERNEL_CONTEXT_PRIO
:
177 return lttng_add_prio_to_ctx(ctx
);
178 case LTTNG_KERNEL_CONTEXT_NICE
:
179 return lttng_add_nice_to_ctx(ctx
);
180 case LTTNG_KERNEL_CONTEXT_VPID
:
181 return lttng_add_vpid_to_ctx(ctx
);
182 case LTTNG_KERNEL_CONTEXT_TID
:
183 return lttng_add_tid_to_ctx(ctx
);
184 case LTTNG_KERNEL_CONTEXT_VTID
:
185 return lttng_add_vtid_to_ctx(ctx
);
186 case LTTNG_KERNEL_CONTEXT_PPID
:
187 return lttng_add_ppid_to_ctx(ctx
);
188 case LTTNG_KERNEL_CONTEXT_VPPID
:
189 return lttng_add_vppid_to_ctx(ctx
);
190 case LTTNG_KERNEL_CONTEXT_PERF_COUNTER
:
191 context_param
.u
.perf_counter
.name
[LTTNG_KERNEL_SYM_NAME_LEN
- 1] = '\0';
192 return lttng_add_perf_counter_to_ctx(context_param
.u
.perf_counter
.type
,
193 context_param
.u
.perf_counter
.config
,
194 context_param
.u
.perf_counter
.name
,
196 case LTTNG_KERNEL_CONTEXT_PROCNAME
:
197 return lttng_add_procname_to_ctx(ctx
);
204 * lttng_ioctl - lttng syscall through ioctl
210 * This ioctl implements lttng commands:
211 * LTTNG_KERNEL_SESSION
212 * Returns a LTTng trace session file descriptor
213 * LTTNG_KERNEL_TRACER_VERSION
214 * Returns the LTTng kernel tracer version
215 * LTTNG_KERNEL_TRACEPOINT_LIST
216 * Returns a file descriptor listing available tracepoints
217 * LTTNG_KERNEL_WAIT_QUIESCENT
218 * Returns after all previously running probes have completed
220 * The returned session will be deleted when its file descriptor is closed.
223 long lttng_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
226 case LTTNG_KERNEL_SESSION
:
227 return lttng_abi_create_session();
228 case LTTNG_KERNEL_TRACER_VERSION
:
229 return lttng_abi_tracer_version(file
,
230 (struct lttng_kernel_tracer_version __user
*) arg
);
231 case LTTNG_KERNEL_TRACEPOINT_LIST
:
232 return lttng_abi_tracepoint_list();
233 case LTTNG_KERNEL_WAIT_QUIESCENT
:
236 case LTTNG_KERNEL_CALIBRATE
:
238 struct lttng_kernel_calibrate __user
*ucalibrate
=
239 (struct lttng_kernel_calibrate __user
*) arg
;
240 struct lttng_kernel_calibrate calibrate
;
243 if (copy_from_user(&calibrate
, ucalibrate
, sizeof(calibrate
)))
245 ret
= lttng_calibrate(&calibrate
);
246 if (copy_to_user(ucalibrate
, &calibrate
, sizeof(calibrate
)))
255 static const struct file_operations lttng_fops
= {
256 .owner
= THIS_MODULE
,
257 .unlocked_ioctl
= lttng_ioctl
,
259 .compat_ioctl
= lttng_ioctl
,
264 * We tolerate no failure in this function (if one happens, we print a dmesg
265 * error, but cannot return any error, because the channel information is
269 void lttng_metadata_create_events(struct file
*channel_file
)
271 struct lttng_channel
*channel
= channel_file
->private_data
;
272 static struct lttng_kernel_event metadata_params
= {
273 .instrumentation
= LTTNG_KERNEL_TRACEPOINT
,
274 .name
= "lttng_metadata",
276 struct lttng_event
*event
;
279 * We tolerate no failure path after event creation. It will stay
280 * invariant for the rest of the session.
282 event
= lttng_event_create(channel
, &metadata_params
, NULL
, NULL
);
290 return; /* not allowed to return error */
294 int lttng_abi_create_channel(struct file
*session_file
,
295 struct lttng_kernel_channel __user
*uchan_param
,
296 enum channel_type channel_type
)
298 struct lttng_session
*session
= session_file
->private_data
;
299 const struct file_operations
*fops
= NULL
;
300 const char *transport_name
;
301 struct lttng_channel
*chan
;
302 struct file
*chan_file
;
303 struct lttng_kernel_channel chan_param
;
307 if (copy_from_user(&chan_param
, uchan_param
, sizeof(chan_param
)))
309 chan_fd
= get_unused_fd();
314 switch (channel_type
) {
315 case PER_CPU_CHANNEL
:
316 fops
= <tng_channel_fops
;
318 case METADATA_CHANNEL
:
319 fops
= <tng_metadata_fops
;
323 chan_file
= anon_inode_getfile("[lttng_channel]",
326 if (IS_ERR(chan_file
)) {
327 ret
= PTR_ERR(chan_file
);
330 switch (channel_type
) {
331 case PER_CPU_CHANNEL
:
332 if (chan_param
.output
== LTTNG_KERNEL_SPLICE
) {
333 transport_name
= chan_param
.overwrite
?
334 "relay-overwrite" : "relay-discard";
335 } else if (chan_param
.output
== LTTNG_KERNEL_MMAP
) {
336 transport_name
= chan_param
.overwrite
?
337 "relay-overwrite-mmap" : "relay-discard-mmap";
342 case METADATA_CHANNEL
:
343 if (chan_param
.output
== LTTNG_KERNEL_SPLICE
)
344 transport_name
= "relay-metadata";
345 else if (chan_param
.output
== LTTNG_KERNEL_MMAP
)
346 transport_name
= "relay-metadata-mmap";
351 transport_name
= "<unknown>";
355 * We tolerate no failure path after channel creation. It will stay
356 * invariant for the rest of the session.
358 chan
= lttng_channel_create(session
, transport_name
, NULL
,
359 chan_param
.subbuf_size
,
360 chan_param
.num_subbuf
,
361 chan_param
.switch_timer_interval
,
362 chan_param
.read_timer_interval
);
367 chan
->file
= chan_file
;
368 chan_file
->private_data
= chan
;
369 fd_install(chan_fd
, chan_file
);
370 if (channel_type
== METADATA_CHANNEL
) {
371 session
->metadata
= chan
;
372 lttng_metadata_create_events(chan_file
);
375 /* The channel created holds a reference on the session */
376 atomic_long_inc(&session_file
->f_count
);
383 put_unused_fd(chan_fd
);
389 * lttng_session_ioctl - lttng session fd ioctl
395 * This ioctl implements lttng commands:
396 * LTTNG_KERNEL_CHANNEL
397 * Returns a LTTng channel file descriptor
398 * LTTNG_KERNEL_ENABLE
399 * Enables tracing for a session (weak enable)
400 * LTTNG_KERNEL_DISABLE
401 * Disables tracing for a session (strong disable)
402 * LTTNG_KERNEL_METADATA
403 * Returns a LTTng metadata file descriptor
405 * The returned channel will be deleted when its file descriptor is closed.
408 long lttng_session_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
410 struct lttng_session
*session
= file
->private_data
;
413 case LTTNG_KERNEL_CHANNEL
:
414 return lttng_abi_create_channel(file
,
415 (struct lttng_kernel_channel __user
*) arg
,
417 case LTTNG_KERNEL_SESSION_START
:
418 case LTTNG_KERNEL_ENABLE
:
419 return lttng_session_enable(session
);
420 case LTTNG_KERNEL_SESSION_STOP
:
421 case LTTNG_KERNEL_DISABLE
:
422 return lttng_session_disable(session
);
423 case LTTNG_KERNEL_METADATA
:
424 return lttng_abi_create_channel(file
,
425 (struct lttng_kernel_channel __user
*) arg
,
433 * Called when the last file reference is dropped.
435 * Big fat note: channels and events are invariant for the whole session after
436 * their creation. So this session destruction also destroys all channel and
437 * event structures specific to this session (they are not destroyed when their
438 * individual file is released).
441 int lttng_session_release(struct inode
*inode
, struct file
*file
)
443 struct lttng_session
*session
= file
->private_data
;
446 lttng_session_destroy(session
);
450 static const struct file_operations lttng_session_fops
= {
451 .owner
= THIS_MODULE
,
452 .release
= lttng_session_release
,
453 .unlocked_ioctl
= lttng_session_ioctl
,
455 .compat_ioctl
= lttng_session_ioctl
,
460 int lttng_abi_open_stream(struct file
*channel_file
)
462 struct lttng_channel
*channel
= channel_file
->private_data
;
463 struct lib_ring_buffer
*buf
;
465 struct file
*stream_file
;
467 buf
= channel
->ops
->buffer_read_open(channel
->chan
);
471 stream_fd
= get_unused_fd();
476 stream_file
= anon_inode_getfile("[lttng_stream]",
477 &lib_ring_buffer_file_operations
,
479 if (IS_ERR(stream_file
)) {
480 ret
= PTR_ERR(stream_file
);
484 * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
485 * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
486 * file descriptor, so we set FMODE_PREAD here.
488 stream_file
->f_mode
|= FMODE_PREAD
;
489 fd_install(stream_fd
, stream_file
);
491 * The stream holds a reference to the channel within the generic ring
492 * buffer library, so no need to hold a refcount on the channel and
493 * session files here.
498 put_unused_fd(stream_fd
);
500 channel
->ops
->buffer_read_close(buf
);
505 int lttng_abi_create_event(struct file
*channel_file
,
506 struct lttng_kernel_event __user
*uevent_param
)
508 struct lttng_channel
*channel
= channel_file
->private_data
;
509 struct lttng_event
*event
;
510 struct lttng_kernel_event event_param
;
512 struct file
*event_file
;
514 if (copy_from_user(&event_param
, uevent_param
, sizeof(event_param
)))
516 event_param
.name
[LTTNG_KERNEL_SYM_NAME_LEN
- 1] = '\0';
517 switch (event_param
.instrumentation
) {
518 case LTTNG_KERNEL_KRETPROBE
:
519 event_param
.u
.kretprobe
.symbol_name
[LTTNG_KERNEL_SYM_NAME_LEN
- 1] = '\0';
521 case LTTNG_KERNEL_KPROBE
:
522 event_param
.u
.kprobe
.symbol_name
[LTTNG_KERNEL_SYM_NAME_LEN
- 1] = '\0';
524 case LTTNG_KERNEL_FUNCTION
:
525 event_param
.u
.ftrace
.symbol_name
[LTTNG_KERNEL_SYM_NAME_LEN
- 1] = '\0';
530 switch (event_param
.instrumentation
) {
532 event_fd
= get_unused_fd();
537 event_file
= anon_inode_getfile("[lttng_event]",
540 if (IS_ERR(event_file
)) {
541 ret
= PTR_ERR(event_file
);
545 * We tolerate no failure path after event creation. It
546 * will stay invariant for the rest of the session.
548 event
= lttng_event_create(channel
, &event_param
, NULL
, NULL
);
553 event_file
->private_data
= event
;
554 fd_install(event_fd
, event_file
);
555 /* The event holds a reference on the channel */
556 atomic_long_inc(&channel_file
->f_count
);
558 case LTTNG_KERNEL_SYSCALL
:
560 * Only all-syscall tracing supported for now.
562 if (event_param
.name
[0] != '\0')
564 ret
= lttng_syscalls_register(channel
, NULL
);
575 put_unused_fd(event_fd
);
581 * lttng_channel_ioctl - lttng syscall through ioctl
587 * This ioctl implements lttng commands:
588 * LTTNG_KERNEL_STREAM
589 * Returns an event stream file descriptor or failure.
590 * (typically, one event stream records events from one CPU)
592 * Returns an event file descriptor or failure.
593 * LTTNG_KERNEL_CONTEXT
594 * Prepend a context field to each event in the channel
595 * LTTNG_KERNEL_ENABLE
596 * Enable recording for events in this channel (weak enable)
597 * LTTNG_KERNEL_DISABLE
598 * Disable recording for events in this channel (strong disable)
600 * Channel and event file descriptors also hold a reference on the session.
603 long lttng_channel_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
605 struct lttng_channel
*channel
= file
->private_data
;
608 case LTTNG_KERNEL_STREAM
:
609 return lttng_abi_open_stream(file
);
610 case LTTNG_KERNEL_EVENT
:
611 return lttng_abi_create_event(file
, (struct lttng_kernel_event __user
*) arg
);
612 case LTTNG_KERNEL_CONTEXT
:
613 return lttng_abi_add_context(file
,
614 (struct lttng_kernel_context __user
*) arg
,
615 &channel
->ctx
, channel
->session
);
616 case LTTNG_KERNEL_ENABLE
:
617 return lttng_channel_enable(channel
);
618 case LTTNG_KERNEL_DISABLE
:
619 return lttng_channel_disable(channel
);
626 * lttng_metadata_ioctl - lttng syscall through ioctl
632 * This ioctl implements lttng commands:
633 * LTTNG_KERNEL_STREAM
634 * Returns an event stream file descriptor or failure.
636 * Channel and event file descriptors also hold a reference on the session.
639 long lttng_metadata_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
642 case LTTNG_KERNEL_STREAM
:
643 return lttng_abi_open_stream(file
);
650 * lttng_channel_poll - lttng stream addition/removal monitoring
655 unsigned int lttng_channel_poll(struct file
*file
, poll_table
*wait
)
657 struct lttng_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
;
678 int lttng_channel_release(struct inode
*inode
, struct file
*file
)
680 struct lttng_channel
*channel
= file
->private_data
;
683 fput(channel
->session
->file
);
687 static const struct file_operations lttng_channel_fops
= {
688 .owner
= THIS_MODULE
,
689 .release
= lttng_channel_release
,
690 .poll
= lttng_channel_poll
,
691 .unlocked_ioctl
= lttng_channel_ioctl
,
693 .compat_ioctl
= lttng_channel_ioctl
,
697 static const struct file_operations lttng_metadata_fops
= {
698 .owner
= THIS_MODULE
,
699 .release
= lttng_channel_release
,
700 .unlocked_ioctl
= lttng_metadata_ioctl
,
702 .compat_ioctl
= lttng_metadata_ioctl
,
707 * lttng_event_ioctl - lttng syscall through ioctl
713 * This ioctl implements lttng commands:
714 * LTTNG_KERNEL_CONTEXT
715 * Prepend a context field to each record of this event
716 * LTTNG_KERNEL_ENABLE
717 * Enable recording for this event (weak enable)
718 * LTTNG_KERNEL_DISABLE
719 * Disable recording for this event (strong disable)
722 long lttng_event_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
724 struct lttng_event
*event
= file
->private_data
;
727 case LTTNG_KERNEL_CONTEXT
:
728 return lttng_abi_add_context(file
,
729 (struct lttng_kernel_context __user
*) arg
,
730 &event
->ctx
, event
->chan
->session
);
731 case LTTNG_KERNEL_ENABLE
:
732 return lttng_event_enable(event
);
733 case LTTNG_KERNEL_DISABLE
:
734 return lttng_event_disable(event
);
741 int lttng_event_release(struct inode
*inode
, struct file
*file
)
743 struct lttng_event
*event
= file
->private_data
;
746 fput(event
->chan
->file
);
750 /* TODO: filter control ioctl */
751 static const struct file_operations lttng_event_fops
= {
752 .owner
= THIS_MODULE
,
753 .release
= lttng_event_release
,
754 .unlocked_ioctl
= lttng_event_ioctl
,
756 .compat_ioctl
= lttng_event_ioctl
,
760 int __init
lttng_abi_init(void)
764 wrapper_vmalloc_sync_all();
765 lttng_proc_dentry
= proc_create_data("lttng", S_IRUSR
| S_IWUSR
, NULL
,
768 if (!lttng_proc_dentry
) {
769 printk(KERN_ERR
"Error creating LTTng control file\n");
777 void __exit
lttng_abi_exit(void)
779 if (lttng_proc_dentry
)
780 remove_proc_entry("lttng", NULL
);