2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
27 #include <common/common.h>
28 #include <common/kernel-ctl/kernel-ctl.h>
29 #include <common/sessiond-comm/sessiond-comm.h>
33 #include "kern-modules.h"
36 * Add context on a kernel channel.
38 int kernel_add_channel_context(struct ltt_kernel_channel
*chan
,
39 struct lttng_kernel_context
*ctx
)
46 DBG("Adding context to channel %s", chan
->channel
->name
);
47 ret
= kernctl_add_context(chan
->fd
, ctx
);
49 if (errno
!= EEXIST
) {
50 PERROR("add context ioctl");
52 /* If EEXIST, we just ignore the error */
58 chan
->ctx
= zmalloc(sizeof(struct lttng_kernel_context
));
59 if (chan
->ctx
== NULL
) {
60 PERROR("zmalloc event context");
64 memcpy(chan
->ctx
, ctx
, sizeof(struct lttng_kernel_context
));
73 * Create a new kernel session, register it to the kernel tracer and add it to
74 * the session daemon session.
76 int kernel_create_session(struct ltt_session
*session
, int tracer_fd
)
79 struct ltt_kernel_session
*lks
;
83 /* Allocate data structure */
84 lks
= trace_kernel_create_session(session
->path
);
90 /* Kernel tracer session creation */
91 ret
= kernctl_create_session(tracer_fd
);
93 PERROR("ioctl kernel create session");
98 /* Prevent fd duplication after execlp() */
99 ret
= fcntl(lks
->fd
, F_SETFD
, FD_CLOEXEC
);
101 PERROR("fcntl session fd");
104 lks
->id
= session
->id
;
105 lks
->consumer_fds_sent
= 0;
106 session
->kernel_session
= lks
;
108 DBG("Kernel session created (fd: %d)", lks
->fd
);
117 * Create a kernel channel, register it to the kernel tracer and add it to the
120 int kernel_create_channel(struct ltt_kernel_session
*session
,
121 struct lttng_channel
*chan
, char *path
)
124 struct ltt_kernel_channel
*lkc
;
130 /* Allocate kernel channel */
131 lkc
= trace_kernel_create_channel(chan
, path
);
136 DBG3("Kernel create channel %s in %s with attr: %d, %" PRIu64
", %" PRIu64
", %u, %u, %d",
137 chan
->name
, path
, lkc
->channel
->attr
.overwrite
,
138 lkc
->channel
->attr
.subbuf_size
, lkc
->channel
->attr
.num_subbuf
,
139 lkc
->channel
->attr
.switch_timer_interval
, lkc
->channel
->attr
.read_timer_interval
,
140 lkc
->channel
->attr
.output
);
142 /* Kernel tracer channel creation */
143 ret
= kernctl_create_channel(session
->fd
, &lkc
->channel
->attr
);
145 PERROR("ioctl kernel create channel");
149 /* Setup the channel fd */
151 /* Prevent fd duplication after execlp() */
152 ret
= fcntl(lkc
->fd
, F_SETFD
, FD_CLOEXEC
);
154 PERROR("fcntl session fd");
157 /* Add channel to session */
158 cds_list_add(&lkc
->list
, &session
->channel_list
.head
);
159 session
->channel_count
++;
160 lkc
->session
= session
;
162 DBG("Kernel channel %s created (fd: %d)", lkc
->channel
->name
, lkc
->fd
);
171 * Create a kernel event, enable it to the kernel tracer and add it to the
172 * channel event list of the kernel session.
174 int kernel_create_event(struct lttng_event
*ev
,
175 struct ltt_kernel_channel
*channel
)
178 struct ltt_kernel_event
*event
;
183 event
= trace_kernel_create_event(ev
);
189 ret
= kernctl_create_event(channel
->fd
, event
->event
);
195 WARN("Event type not implemented");
198 PERROR("create event ioctl");
205 * LTTNG_KERNEL_SYSCALL event creation will return 0 on success.
207 if (ret
== 0 && event
->event
->instrumentation
== LTTNG_KERNEL_SYSCALL
) {
208 DBG2("Kernel event syscall creation success");
210 * We use fd == -1 to ensure that we never trigger a close of fd
218 /* Prevent fd duplication after execlp() */
219 ret
= fcntl(event
->fd
, F_SETFD
, FD_CLOEXEC
);
221 PERROR("fcntl session fd");
225 /* Add event to event list */
226 cds_list_add(&event
->list
, &channel
->events_list
.head
);
227 channel
->event_count
++;
229 DBG("Event %s created (fd: %d)", ev
->name
, event
->fd
);
240 * Disable a kernel channel.
242 int kernel_disable_channel(struct ltt_kernel_channel
*chan
)
248 ret
= kernctl_disable(chan
->fd
);
250 PERROR("disable chan ioctl");
256 DBG("Kernel channel %s disabled (fd: %d)", chan
->channel
->name
, chan
->fd
);
265 * Enable a kernel channel.
267 int kernel_enable_channel(struct ltt_kernel_channel
*chan
)
273 ret
= kernctl_enable(chan
->fd
);
274 if (ret
< 0 && errno
!= EEXIST
) {
275 PERROR("Enable kernel chan");
280 DBG("Kernel channel %s enabled (fd: %d)", chan
->channel
->name
, chan
->fd
);
289 * Enable a kernel event.
291 int kernel_enable_event(struct ltt_kernel_event
*event
)
297 ret
= kernctl_enable(event
->fd
);
301 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
304 PERROR("enable kernel event");
311 DBG("Kernel event %s enabled (fd: %d)", event
->event
->name
, event
->fd
);
320 * Disable a kernel event.
322 int kernel_disable_event(struct ltt_kernel_event
*event
)
328 ret
= kernctl_disable(event
->fd
);
332 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
335 PERROR("disable kernel event");
342 DBG("Kernel event %s disabled (fd: %d)", event
->event
->name
, event
->fd
);
351 * Create kernel metadata, open from the kernel tracer and add it to the
354 int kernel_open_metadata(struct ltt_kernel_session
*session
)
357 struct ltt_kernel_metadata
*lkm
;
361 /* Allocate kernel metadata */
362 lkm
= trace_kernel_create_metadata();
367 /* Kernel tracer metadata creation */
368 ret
= kernctl_open_metadata(session
->fd
, &lkm
->conf
->attr
);
374 /* Prevent fd duplication after execlp() */
375 ret
= fcntl(lkm
->fd
, F_SETFD
, FD_CLOEXEC
);
377 PERROR("fcntl session fd");
380 session
->metadata
= lkm
;
382 DBG("Kernel metadata opened (fd: %d)", lkm
->fd
);
391 * Start tracing session.
393 int kernel_start_session(struct ltt_kernel_session
*session
)
399 ret
= kernctl_start_session(session
->fd
);
401 PERROR("ioctl start session");
405 DBG("Kernel session started");
414 * Make a kernel wait to make sure in-flight probe have completed.
416 void kernel_wait_quiescent(int fd
)
420 DBG("Kernel quiescent wait on %d", fd
);
422 ret
= kernctl_wait_quiescent(fd
);
424 PERROR("wait quiescent ioctl");
425 ERR("Kernel quiescent wait failed");
432 int kernel_calibrate(int fd
, struct lttng_kernel_calibrate
*calibrate
)
438 ret
= kernctl_calibrate(fd
, calibrate
);
440 PERROR("calibrate ioctl");
449 * Force flush buffer of metadata.
451 int kernel_metadata_flush_buffer(int fd
)
455 ret
= kernctl_buffer_flush(fd
);
457 ERR("Fail to flush metadata buffers %d (ret: %d)", fd
, ret
);
464 * Force flush buffer for channel.
466 int kernel_flush_buffer(struct ltt_kernel_channel
*channel
)
469 struct ltt_kernel_stream
*stream
;
473 DBG("Flush buffer for channel %s", channel
->channel
->name
);
475 cds_list_for_each_entry(stream
, &channel
->stream_list
.head
, list
) {
476 DBG("Flushing channel stream %d", stream
->fd
);
477 ret
= kernctl_buffer_flush(stream
->fd
);
480 ERR("Fail to flush buffer for stream %d (ret: %d)",
489 * Stop tracing session.
491 int kernel_stop_session(struct ltt_kernel_session
*session
)
497 ret
= kernctl_stop_session(session
->fd
);
502 DBG("Kernel session stopped");
511 * Open stream of channel, register it to the kernel tracer and add it
512 * to the stream list of the channel.
514 * Return the number of created stream. Else, a negative value.
516 int kernel_open_channel_stream(struct ltt_kernel_channel
*channel
)
519 struct ltt_kernel_stream
*lks
;
523 while ((ret
= kernctl_create_stream(channel
->fd
)) >= 0) {
524 lks
= trace_kernel_create_stream(channel
->channel
->name
, count
);
534 /* Prevent fd duplication after execlp() */
535 ret
= fcntl(lks
->fd
, F_SETFD
, FD_CLOEXEC
);
537 PERROR("fcntl session fd");
540 /* Add stream to channe stream list */
541 cds_list_add(&lks
->list
, &channel
->stream_list
.head
);
542 channel
->stream_count
++;
544 /* Increment counter which represent CPU number. */
547 DBG("Kernel stream %s created (fd: %d, state: %d)", lks
->name
, lks
->fd
,
551 return channel
->stream_count
;
558 * Open the metadata stream and set it to the kernel session.
560 int kernel_open_metadata_stream(struct ltt_kernel_session
*session
)
566 ret
= kernctl_create_stream(session
->metadata
->fd
);
568 PERROR("kernel create metadata stream");
572 DBG("Kernel metadata stream created (fd: %d)", ret
);
573 session
->metadata_stream_fd
= ret
;
574 /* Prevent fd duplication after execlp() */
575 ret
= fcntl(session
->metadata_stream_fd
, F_SETFD
, FD_CLOEXEC
);
577 PERROR("fcntl session fd");
587 * Get the event list from the kernel tracer and return the number of elements.
589 ssize_t
kernel_list_events(int tracer_fd
, struct lttng_event
**events
)
593 size_t nbmem
, count
= 0;
595 struct lttng_event
*elist
;
599 fd
= kernctl_tracepoint_list(tracer_fd
);
601 PERROR("kernel tracepoint list");
605 fp
= fdopen(fd
, "r");
607 PERROR("kernel tracepoint list fdopen");
612 * Init memory size counter
613 * See kernel-ctl.h for explanation of this value
615 nbmem
= KERNEL_EVENT_INIT_LIST_SIZE
;
616 elist
= zmalloc(sizeof(struct lttng_event
) * nbmem
);
618 PERROR("alloc list events");
623 while (fscanf(fp
, "event { name = %m[^;]; };%n\n", &event
, &pos
) == 1) {
624 if (count
>= nbmem
) {
625 struct lttng_event
*new_elist
;
627 DBG("Reallocating event list from %zu to %zu bytes", nbmem
,
629 /* Double the size */
631 new_elist
= realloc(elist
, nbmem
* sizeof(struct lttng_event
));
632 if (new_elist
== NULL
) {
633 PERROR("realloc list events");
641 strncpy(elist
[count
].name
, event
, LTTNG_SYMBOL_NAME_LEN
);
642 elist
[count
].name
[LTTNG_SYMBOL_NAME_LEN
- 1] = '\0';
643 elist
[count
].enabled
= -1;
649 DBG("Kernel list events done (%zu events)", count
);
651 ret
= fclose(fp
); /* closes both fp and fd */
667 * Get kernel version and validate it.
669 int kernel_validate_version(int tracer_fd
)
672 struct lttng_kernel_tracer_version version
;
674 ret
= kernctl_tracer_version(tracer_fd
, &version
);
676 ERR("Failed at getting the lttng-modules version");
680 /* Validate version */
681 if (version
.major
!= KERN_MODULES_PRE_MAJOR
682 && version
.major
!= KERN_MODULES_MAJOR
) {
686 DBG2("Kernel tracer version validated (major version %d)", version
.major
);
690 ERR("Kernel major version %d is not compatible (supporting <= %d)",
691 version
.major
, KERN_MODULES_MAJOR
)
699 * Kernel work-arounds called at the start of sessiond main().
701 int init_kernel_workarounds(void)
707 * boot_id needs to be read once before being used concurrently
708 * to deal with a Linux kernel race. A fix is proposed for
709 * upstream, but the work-around is needed for older kernels.
711 fp
= fopen("/proc/sys/kernel/random/boot_id", "r");
718 ret
= fread(buf
, 1, sizeof(buf
), fp
);
720 /* Ignore error, we don't really care */
732 * Complete teardown of a kernel session.
734 void kernel_destroy_session(struct ltt_kernel_session
*ksess
)
737 DBG3("No kernel session when tearing down session");
741 DBG("Tearing down kernel session");
743 /* Close any relayd session */
744 consumer_output_send_destroy_relayd(ksess
->consumer
);
746 trace_kernel_destroy_session(ksess
);
750 * Destroy a kernel channel object. It does not do anything on the tracer side.
752 void kernel_destroy_channel(struct ltt_kernel_channel
*kchan
)
754 struct ltt_kernel_session
*ksess
= NULL
;
757 assert(kchan
->channel
);
759 DBG3("Kernel destroy channel %s", kchan
->channel
->name
);
761 /* Update channel count of associated session. */
762 if (kchan
->session
) {
763 /* Keep pointer reference so we can update it after the destroy. */
764 ksess
= kchan
->session
;
767 trace_kernel_destroy_channel(kchan
);
770 * At this point the kernel channel is not visible anymore. This is safe
771 * since in order to work on a visible kernel session, the tracing session
772 * lock (ltt_session.lock) MUST be acquired.
775 ksess
->channel_count
--;