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.
26 #include <common/common.h>
27 #include <common/kernel-ctl/kernel-ctl.h>
28 #include <common/kernel-ctl/kernel-ioctl.h>
29 #include <common/sessiond-comm/sessiond-comm.h>
33 #include "kernel-consumer.h"
34 #include "kern-modules.h"
39 * Key used to reference a channel between the sessiond and the consumer. This
40 * is only read and updated with the session_list lock held.
42 static uint64_t next_kernel_channel_key
;
44 #include <lttng/userspace-probe.h>
45 #include <lttng/userspace-probe-internal.h>
47 * Add context on a kernel channel.
49 * Assumes the ownership of ctx.
51 int kernel_add_channel_context(struct ltt_kernel_channel
*chan
,
52 struct ltt_kernel_context
*ctx
)
59 DBG("Adding context to channel %s", chan
->channel
->name
);
60 ret
= kernctl_add_context(chan
->fd
, &ctx
->ctx
);
64 /* Exists but not available for this kernel */
65 ret
= LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE
;
68 /* If EEXIST, we just ignore the error */
72 PERROR("add context ioctl");
73 ret
= LTTNG_ERR_KERN_CONTEXT_FAIL
;
80 cds_list_add_tail(&ctx
->list
, &chan
->ctx_list
);
85 trace_kernel_destroy_context(ctx
);
91 * Create a new kernel session, register it to the kernel tracer and add it to
92 * the session daemon session.
94 int kernel_create_session(struct ltt_session
*session
, int tracer_fd
)
97 struct ltt_kernel_session
*lks
;
101 /* Allocate data structure */
102 lks
= trace_kernel_create_session();
108 /* Kernel tracer session creation */
109 ret
= kernctl_create_session(tracer_fd
);
111 PERROR("ioctl kernel create session");
116 /* Prevent fd duplication after execlp() */
117 ret
= fcntl(lks
->fd
, F_SETFD
, FD_CLOEXEC
);
119 PERROR("fcntl session fd");
122 lks
->id
= session
->id
;
123 lks
->consumer_fds_sent
= 0;
124 session
->kernel_session
= lks
;
126 DBG("Kernel session created (fd: %d)", lks
->fd
);
128 ret
= kernctl_session_set_name(lks
->fd
, session
->name
);
130 WARN("Could not set kernel session name");
133 ret
= kernctl_session_set_creation_time(lks
->fd
, session
->creation_time
);
135 WARN("Could not set kernel session creation time");
142 trace_kernel_destroy_session(lks
);
148 * Create a kernel channel, register it to the kernel tracer and add it to the
151 int kernel_create_channel(struct ltt_kernel_session
*session
,
152 struct lttng_channel
*chan
)
155 struct ltt_kernel_channel
*lkc
;
160 /* Allocate kernel channel */
161 lkc
= trace_kernel_create_channel(chan
);
166 DBG3("Kernel create channel %s with attr: %d, %" PRIu64
", %" PRIu64
", %u, %u, %d, %d",
167 chan
->name
, lkc
->channel
->attr
.overwrite
,
168 lkc
->channel
->attr
.subbuf_size
, lkc
->channel
->attr
.num_subbuf
,
169 lkc
->channel
->attr
.switch_timer_interval
, lkc
->channel
->attr
.read_timer_interval
,
170 lkc
->channel
->attr
.live_timer_interval
, lkc
->channel
->attr
.output
);
172 /* Kernel tracer channel creation */
173 ret
= kernctl_create_channel(session
->fd
, &lkc
->channel
->attr
);
175 PERROR("ioctl kernel create channel");
179 /* Setup the channel fd */
181 /* Prevent fd duplication after execlp() */
182 ret
= fcntl(lkc
->fd
, F_SETFD
, FD_CLOEXEC
);
184 PERROR("fcntl session fd");
187 /* Add channel to session */
188 cds_list_add(&lkc
->list
, &session
->channel_list
.head
);
189 session
->channel_count
++;
190 lkc
->session
= session
;
191 lkc
->key
= ++next_kernel_channel_key
;
193 DBG("Kernel channel %s created (fd: %d, key: %" PRIu64
")",
194 lkc
->channel
->name
, lkc
->fd
, lkc
->key
);
207 * Compute the offset of the instrumentation byte in the binary based on the
208 * function probe location using the ELF lookup method.
210 * Returns 0 on success and set the offset out parameter to the offset of the
212 * Returns -1 on error
215 int extract_userspace_probe_offset_function_elf(
216 const struct lttng_userspace_probe_location
*probe_location
,
217 struct ltt_kernel_session
*session
, uint64_t *offset
)
221 const char *symbol
= NULL
;
222 const struct lttng_userspace_probe_location_lookup_method
*lookup
= NULL
;
223 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type
;
225 assert(lttng_userspace_probe_location_get_type(probe_location
) ==
226 LTTNG_USERSPACE_PROBE_LOCATION_TYPE_FUNCTION
);
228 lookup
= lttng_userspace_probe_location_get_lookup_method(
236 lttng_userspace_probe_location_lookup_method_get_type(lookup
);
238 assert(lookup_method_type
==
239 LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF
);
241 symbol
= lttng_userspace_probe_location_function_get_function_name(
248 fd
= lttng_userspace_probe_location_function_get_binary_fd(probe_location
);
254 ret
= run_as_extract_elf_symbol_offset(fd
, symbol
, session
->uid
,
255 session
->gid
, offset
);
257 DBG("userspace probe offset calculation failed for "
258 "function %s", symbol
);
262 DBG("userspace probe elf offset for %s is 0x%jd", symbol
, (intmax_t)(*offset
));
268 * Compute the offsets of the instrumentation bytes in the binary based on the
269 * tracepoint probe location using the SDT lookup method. This function
270 * allocates the offsets buffer, the caller must free it.
272 * Returns 0 on success and set the offset out parameter to the offsets of the
274 * Returns -1 on error.
277 int extract_userspace_probe_offset_tracepoint_sdt(
278 const struct lttng_userspace_probe_location
*probe_location
,
279 struct ltt_kernel_session
*session
, uint64_t **offsets
,
280 uint32_t *offsets_count
)
282 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type
;
283 const struct lttng_userspace_probe_location_lookup_method
*lookup
= NULL
;
284 const char *probe_name
= NULL
, *provider_name
= NULL
;
288 assert(lttng_userspace_probe_location_get_type(probe_location
) ==
289 LTTNG_USERSPACE_PROBE_LOCATION_TYPE_TRACEPOINT
);
291 lookup
= lttng_userspace_probe_location_get_lookup_method(probe_location
);
298 lttng_userspace_probe_location_lookup_method_get_type(lookup
);
300 assert(lookup_method_type
==
301 LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT
);
304 probe_name
= lttng_userspace_probe_location_tracepoint_get_probe_name(
311 provider_name
= lttng_userspace_probe_location_tracepoint_get_provider_name(
313 if (!provider_name
) {
318 fd
= lttng_userspace_probe_location_tracepoint_get_binary_fd(probe_location
);
324 ret
= run_as_extract_sdt_probe_offsets(fd
, provider_name
, probe_name
,
325 session
->uid
, session
->gid
, offsets
, offsets_count
);
327 DBG("userspace probe offset calculation failed for sdt "
328 "probe %s:%s", provider_name
, probe_name
);
332 if (*offsets_count
== 0) {
333 DBG("no userspace probe offset found");
337 DBG("%u userspace probe SDT offsets found for %s:%s at:",
338 *offsets_count
, provider_name
, probe_name
);
339 for (i
= 0; i
< *offsets_count
; i
++) {
340 DBG("\t0x%jd", (intmax_t)((*offsets
)[i
]));
347 * Extract the offsets of the instrumentation point for the different lookup
351 int userspace_probe_add_callsites(struct lttng_event
*ev
,
352 struct ltt_kernel_session
*session
, int fd
)
354 const struct lttng_userspace_probe_location_lookup_method
*lookup_method
= NULL
;
355 enum lttng_userspace_probe_location_lookup_method_type type
;
356 const struct lttng_userspace_probe_location
*location
= NULL
;
360 assert(ev
->type
== LTTNG_EVENT_USERSPACE_PROBE
);
362 location
= lttng_event_get_userspace_probe_location(ev
);
368 lttng_userspace_probe_location_get_lookup_method(location
);
369 if (!lookup_method
) {
374 type
= lttng_userspace_probe_location_lookup_method_get_type(lookup_method
);
376 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF
:
378 struct lttng_kernel_event_callsite callsite
;
381 ret
= extract_userspace_probe_offset_function_elf(location
, session
, &offset
);
383 ret
= LTTNG_ERR_PROBE_LOCATION_INVAL
;
387 callsite
.u
.uprobe
.offset
= offset
;
388 ret
= kernctl_add_callsite(fd
, &callsite
);
390 WARN("Adding callsite to userspace probe "
391 "event %s failed.", ev
->name
);
392 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
397 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT
:
400 uint64_t *offsets
= NULL
;
401 uint32_t offsets_count
;
402 struct lttng_kernel_event_callsite callsite
;
405 * This call allocates the offsets buffer. This buffer must be freed
408 ret
= extract_userspace_probe_offset_tracepoint_sdt(location
, session
,
409 &offsets
, &offsets_count
);
411 ret
= LTTNG_ERR_PROBE_LOCATION_INVAL
;
414 for (i
= 0; i
< offsets_count
; i
++) {
415 callsite
.u
.uprobe
.offset
= offsets
[i
];
416 ret
= kernctl_add_callsite(fd
, &callsite
);
418 WARN("Adding callsite to userspace probe "
419 "event %s failed.", ev
->name
);
420 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
429 ret
= LTTNG_ERR_PROBE_LOCATION_INVAL
;
437 * Create a kernel event, enable it to the kernel tracer and add it to the
438 * channel event list of the kernel session.
439 * We own filter_expression and filter.
441 int kernel_create_event(struct lttng_event
*ev
,
442 struct ltt_kernel_channel
*channel
,
443 char *filter_expression
,
444 struct lttng_filter_bytecode
*filter
)
447 enum lttng_error_code ret
;
448 struct ltt_kernel_event
*event
;
453 /* We pass ownership of filter_expression and filter */
454 ret
= trace_kernel_create_event(ev
, filter_expression
,
456 if (ret
!= LTTNG_OK
) {
460 fd
= kernctl_create_event(channel
->fd
, event
->event
);
464 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
467 WARN("Event type not implemented");
468 ret
= LTTNG_ERR_KERN_EVENT_ENOSYS
;
471 WARN("Event %s not found!", ev
->name
);
472 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
475 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
476 PERROR("create event ioctl");
481 event
->type
= ev
->type
;
483 /* Prevent fd duplication after execlp() */
484 err
= fcntl(event
->fd
, F_SETFD
, FD_CLOEXEC
);
486 PERROR("fcntl session fd");
490 err
= kernctl_filter(event
->fd
, filter
);
494 ret
= LTTNG_ERR_FILTER_NOMEM
;
497 ret
= LTTNG_ERR_FILTER_INVAL
;
504 if (ev
->type
== LTTNG_EVENT_USERSPACE_PROBE
) {
505 ret
= userspace_probe_add_callsites(ev
, channel
->session
, event
->fd
);
507 goto add_callsite_error
;
511 err
= kernctl_enable(event
->fd
);
515 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
518 PERROR("enable kernel event");
519 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
525 /* Add event to event list */
526 cds_list_add(&event
->list
, &channel
->events_list
.head
);
527 channel
->event_count
++;
529 DBG("Event %s created (fd: %d)", ev
->name
, event
->fd
);
539 closeret
= close(event
->fd
);
541 PERROR("close event fd");
551 * Disable a kernel channel.
553 int kernel_disable_channel(struct ltt_kernel_channel
*chan
)
559 ret
= kernctl_disable(chan
->fd
);
561 PERROR("disable chan ioctl");
566 DBG("Kernel channel %s disabled (fd: %d, key: %" PRIu64
")",
567 chan
->channel
->name
, chan
->fd
, chan
->key
);
576 * Enable a kernel channel.
578 int kernel_enable_channel(struct ltt_kernel_channel
*chan
)
584 ret
= kernctl_enable(chan
->fd
);
585 if (ret
< 0 && ret
!= -EEXIST
) {
586 PERROR("Enable kernel chan");
591 DBG("Kernel channel %s enabled (fd: %d, key: %" PRIu64
")",
592 chan
->channel
->name
, chan
->fd
, chan
->key
);
601 * Enable a kernel event.
603 int kernel_enable_event(struct ltt_kernel_event
*event
)
609 ret
= kernctl_enable(event
->fd
);
613 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
616 PERROR("enable kernel event");
623 DBG("Kernel event %s enabled (fd: %d)", event
->event
->name
, event
->fd
);
632 * Disable a kernel event.
634 int kernel_disable_event(struct ltt_kernel_event
*event
)
640 ret
= kernctl_disable(event
->fd
);
644 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
647 PERROR("disable kernel event");
654 DBG("Kernel event %s disabled (fd: %d)", event
->event
->name
, event
->fd
);
663 int kernel_track_pid(struct ltt_kernel_session
*session
, int pid
)
667 DBG("Kernel track PID %d for session id %" PRIu64
".",
669 ret
= kernctl_track_pid(session
->fd
, pid
);
675 return LTTNG_ERR_INVALID
;
677 return LTTNG_ERR_NOMEM
;
679 return LTTNG_ERR_PID_TRACKED
;
681 return LTTNG_ERR_UNK
;
685 int kernel_untrack_pid(struct ltt_kernel_session
*session
, int pid
)
689 DBG("Kernel untrack PID %d for session id %" PRIu64
".",
691 ret
= kernctl_untrack_pid(session
->fd
, pid
);
697 return LTTNG_ERR_INVALID
;
699 return LTTNG_ERR_NOMEM
;
701 return LTTNG_ERR_PID_NOT_TRACKED
;
703 return LTTNG_ERR_UNK
;
707 ssize_t
kernel_list_tracker_pids(struct ltt_kernel_session
*session
,
712 ssize_t nbmem
, count
= 0;
716 fd
= kernctl_list_tracker_pids(session
->fd
);
718 PERROR("kernel tracker pids list");
722 fp
= fdopen(fd
, "r");
724 PERROR("kernel tracker pids list fdopen");
728 nbmem
= KERNEL_TRACKER_PIDS_INIT_LIST_SIZE
;
729 pids
= zmalloc(sizeof(*pids
) * nbmem
);
731 PERROR("alloc list pids");
736 while (fscanf(fp
, "process { pid = %u; };\n", &pid
) == 1) {
737 if (count
>= nbmem
) {
741 new_nbmem
= nbmem
<< 1;
742 DBG("Reallocating pids list from %zu to %zu entries",
744 new_pids
= realloc(pids
, new_nbmem
* sizeof(*new_pids
));
745 if (new_pids
== NULL
) {
746 PERROR("realloc list events");
751 /* Zero the new memory */
752 memset(new_pids
+ nbmem
, 0,
753 (new_nbmem
- nbmem
) * sizeof(*new_pids
));
761 DBG("Kernel list tracker pids done (%zd pids)", count
);
763 ret
= fclose(fp
); /* closes both fp and fd */
779 * Create kernel metadata, open from the kernel tracer and add it to the
782 int kernel_open_metadata(struct ltt_kernel_session
*session
)
785 struct ltt_kernel_metadata
*lkm
= NULL
;
789 /* Allocate kernel metadata */
790 lkm
= trace_kernel_create_metadata();
795 /* Kernel tracer metadata creation */
796 ret
= kernctl_open_metadata(session
->fd
, &lkm
->conf
->attr
);
802 lkm
->key
= ++next_kernel_channel_key
;
803 /* Prevent fd duplication after execlp() */
804 ret
= fcntl(lkm
->fd
, F_SETFD
, FD_CLOEXEC
);
806 PERROR("fcntl session fd");
809 session
->metadata
= lkm
;
811 DBG("Kernel metadata opened (fd: %d)", lkm
->fd
);
816 trace_kernel_destroy_metadata(lkm
);
822 * Start tracing session.
824 int kernel_start_session(struct ltt_kernel_session
*session
)
830 ret
= kernctl_start_session(session
->fd
);
832 PERROR("ioctl start session");
836 DBG("Kernel session started");
845 * Make a kernel wait to make sure in-flight probe have completed.
847 void kernel_wait_quiescent(int fd
)
851 DBG("Kernel quiescent wait on %d", fd
);
853 ret
= kernctl_wait_quiescent(fd
);
855 PERROR("wait quiescent ioctl");
856 ERR("Kernel quiescent wait failed");
861 * Force flush buffer of metadata.
863 int kernel_metadata_flush_buffer(int fd
)
867 DBG("Kernel flushing metadata buffer on fd %d", fd
);
869 ret
= kernctl_buffer_flush(fd
);
871 ERR("Fail to flush metadata buffers %d (ret: %d)", fd
, ret
);
878 * Force flush buffer for channel.
880 int kernel_flush_buffer(struct ltt_kernel_channel
*channel
)
883 struct ltt_kernel_stream
*stream
;
887 DBG("Flush buffer for channel %s", channel
->channel
->name
);
889 cds_list_for_each_entry(stream
, &channel
->stream_list
.head
, list
) {
890 DBG("Flushing channel stream %d", stream
->fd
);
891 ret
= kernctl_buffer_flush(stream
->fd
);
894 ERR("Fail to flush buffer for stream %d (ret: %d)",
903 * Stop tracing session.
905 int kernel_stop_session(struct ltt_kernel_session
*session
)
911 ret
= kernctl_stop_session(session
->fd
);
916 DBG("Kernel session stopped");
925 * Open stream of channel, register it to the kernel tracer and add it
926 * to the stream list of the channel.
928 * Note: given that the streams may appear in random order wrt CPU
929 * number (e.g. cpu hotplug), the index value of the stream number in
930 * the stream name is not necessarily linked to the CPU number.
932 * Return the number of created stream. Else, a negative value.
934 int kernel_open_channel_stream(struct ltt_kernel_channel
*channel
)
937 struct ltt_kernel_stream
*lks
;
941 while ((ret
= kernctl_create_stream(channel
->fd
)) >= 0) {
942 lks
= trace_kernel_create_stream(channel
->channel
->name
,
943 channel
->stream_count
);
953 /* Prevent fd duplication after execlp() */
954 ret
= fcntl(lks
->fd
, F_SETFD
, FD_CLOEXEC
);
956 PERROR("fcntl session fd");
959 lks
->tracefile_size
= channel
->channel
->attr
.tracefile_size
;
960 lks
->tracefile_count
= channel
->channel
->attr
.tracefile_count
;
962 /* Add stream to channel stream list */
963 cds_list_add(&lks
->list
, &channel
->stream_list
.head
);
964 channel
->stream_count
++;
966 DBG("Kernel stream %s created (fd: %d, state: %d)", lks
->name
, lks
->fd
,
970 return channel
->stream_count
;
977 * Open the metadata stream and set it to the kernel session.
979 int kernel_open_metadata_stream(struct ltt_kernel_session
*session
)
985 ret
= kernctl_create_stream(session
->metadata
->fd
);
987 PERROR("kernel create metadata stream");
991 DBG("Kernel metadata stream created (fd: %d)", ret
);
992 session
->metadata_stream_fd
= ret
;
993 /* Prevent fd duplication after execlp() */
994 ret
= fcntl(session
->metadata_stream_fd
, F_SETFD
, FD_CLOEXEC
);
996 PERROR("fcntl session fd");
1006 * Get the event list from the kernel tracer and return the number of elements.
1008 ssize_t
kernel_list_events(int tracer_fd
, struct lttng_event
**events
)
1012 size_t nbmem
, count
= 0;
1014 struct lttng_event
*elist
;
1018 fd
= kernctl_tracepoint_list(tracer_fd
);
1020 PERROR("kernel tracepoint list");
1024 fp
= fdopen(fd
, "r");
1026 PERROR("kernel tracepoint list fdopen");
1031 * Init memory size counter
1032 * See kernel-ctl.h for explanation of this value
1034 nbmem
= KERNEL_EVENT_INIT_LIST_SIZE
;
1035 elist
= zmalloc(sizeof(struct lttng_event
) * nbmem
);
1036 if (elist
== NULL
) {
1037 PERROR("alloc list events");
1042 while (fscanf(fp
, "event { name = %m[^;]; };\n", &event
) == 1) {
1043 if (count
>= nbmem
) {
1044 struct lttng_event
*new_elist
;
1047 new_nbmem
= nbmem
<< 1;
1048 DBG("Reallocating event list from %zu to %zu bytes",
1050 new_elist
= realloc(elist
, new_nbmem
* sizeof(struct lttng_event
));
1051 if (new_elist
== NULL
) {
1052 PERROR("realloc list events");
1058 /* Zero the new memory */
1059 memset(new_elist
+ nbmem
, 0,
1060 (new_nbmem
- nbmem
) * sizeof(struct lttng_event
));
1064 strncpy(elist
[count
].name
, event
, LTTNG_SYMBOL_NAME_LEN
);
1065 elist
[count
].name
[LTTNG_SYMBOL_NAME_LEN
- 1] = '\0';
1066 elist
[count
].enabled
= -1;
1072 DBG("Kernel list events done (%zu events)", count
);
1074 ret
= fclose(fp
); /* closes both fp and fd */
1090 * Get kernel version and validate it.
1092 int kernel_validate_version(int tracer_fd
,
1093 struct lttng_kernel_tracer_version
*version
,
1094 struct lttng_kernel_tracer_abi_version
*abi_version
)
1098 ret
= kernctl_tracer_version(tracer_fd
, version
);
1100 ERR("Failed to retrieve the lttng-modules version");
1104 /* Validate version */
1105 if (version
->major
!= VERSION_MAJOR
) {
1106 ERR("Kernel tracer major version (%d) is not compatible with lttng-tools major version (%d)",
1107 version
->major
, VERSION_MAJOR
);
1110 ret
= kernctl_tracer_abi_version(tracer_fd
, abi_version
);
1112 ERR("Failed to retrieve lttng-modules ABI version");
1115 if (abi_version
->major
!= LTTNG_MODULES_ABI_MAJOR_VERSION
) {
1116 ERR("Kernel tracer ABI version (%d.%d) does not match the expected ABI major version (%d.*)",
1117 abi_version
->major
, abi_version
->minor
,
1118 LTTNG_MODULES_ABI_MAJOR_VERSION
);
1121 DBG2("Kernel tracer version validated (%d.%d, ABI %d.%d)",
1122 version
->major
, version
->minor
,
1123 abi_version
->major
, abi_version
->minor
);
1130 ERR("Kernel tracer version check failed; kernel tracing will not be available");
1135 * Kernel work-arounds called at the start of sessiond main().
1137 int init_kernel_workarounds(void)
1143 * boot_id needs to be read once before being used concurrently
1144 * to deal with a Linux kernel race. A fix is proposed for
1145 * upstream, but the work-around is needed for older kernels.
1147 fp
= fopen("/proc/sys/kernel/random/boot_id", "r");
1154 ret
= fread(buf
, 1, sizeof(buf
), fp
);
1156 /* Ignore error, we don't really care */
1168 * Complete teardown of a kernel session.
1170 void kernel_destroy_session(struct ltt_kernel_session
*ksess
)
1172 if (ksess
== NULL
) {
1173 DBG3("No kernel session when tearing down session");
1177 DBG("Tearing down kernel session");
1180 * Destroy channels on the consumer if at least one FD has been sent and we
1181 * are in no output mode because the streams are in *no* monitor mode so we
1182 * have to send a command to clean them up or else they leaked.
1184 if (!ksess
->output_traces
&& ksess
->consumer_fds_sent
) {
1186 struct consumer_socket
*socket
;
1187 struct lttng_ht_iter iter
;
1189 /* For each consumer socket. */
1191 cds_lfht_for_each_entry(ksess
->consumer
->socks
->ht
, &iter
.iter
,
1192 socket
, node
.node
) {
1193 struct ltt_kernel_channel
*chan
;
1195 /* For each channel, ask the consumer to destroy it. */
1196 cds_list_for_each_entry(chan
, &ksess
->channel_list
.head
, list
) {
1197 ret
= kernel_consumer_destroy_channel(socket
, chan
);
1199 /* Consumer is probably dead. Use next socket. */
1207 /* Close any relayd session */
1208 consumer_output_send_destroy_relayd(ksess
->consumer
);
1210 trace_kernel_destroy_session(ksess
);
1214 * Destroy a kernel channel object. It does not do anything on the tracer side.
1216 void kernel_destroy_channel(struct ltt_kernel_channel
*kchan
)
1218 struct ltt_kernel_session
*ksess
= NULL
;
1221 assert(kchan
->channel
);
1223 DBG3("Kernel destroy channel %s", kchan
->channel
->name
);
1225 /* Update channel count of associated session. */
1226 if (kchan
->session
) {
1227 /* Keep pointer reference so we can update it after the destroy. */
1228 ksess
= kchan
->session
;
1231 trace_kernel_destroy_channel(kchan
);
1234 * At this point the kernel channel is not visible anymore. This is safe
1235 * since in order to work on a visible kernel session, the tracing session
1236 * lock (ltt_session.lock) MUST be acquired.
1239 ksess
->channel_count
--;
1244 * Take a snapshot for a given kernel session.
1246 * Return LTTNG_OK on success or else return a LTTNG_ERR code.
1248 enum lttng_error_code
kernel_snapshot_record(struct ltt_kernel_session
*ksess
,
1249 struct snapshot_output
*output
, int wait
,
1250 uint64_t nb_packets_per_stream
)
1252 int err
, ret
, saved_metadata_fd
;
1253 enum lttng_error_code status
= LTTNG_OK
;
1254 struct consumer_socket
*socket
;
1255 struct lttng_ht_iter iter
;
1256 struct ltt_kernel_metadata
*saved_metadata
;
1257 struct ltt_session
*session
= NULL
;
1258 uint64_t trace_archive_id
;
1261 assert(ksess
->consumer
);
1264 DBG("Kernel snapshot record started");
1266 session
= session_find_by_id(ksess
->id
);
1268 assert(pthread_mutex_trylock(&session
->lock
));
1269 assert(session_trylock_list());
1270 trace_archive_id
= session
->current_archive_id
;
1272 /* Save current metadata since the following calls will change it. */
1273 saved_metadata
= ksess
->metadata
;
1274 saved_metadata_fd
= ksess
->metadata_stream_fd
;
1278 ret
= kernel_open_metadata(ksess
);
1280 status
= LTTNG_ERR_KERN_META_FAIL
;
1284 ret
= kernel_open_metadata_stream(ksess
);
1286 status
= LTTNG_ERR_KERN_META_FAIL
;
1287 goto error_open_stream
;
1290 /* Send metadata to consumer and snapshot everything. */
1291 cds_lfht_for_each_entry(ksess
->consumer
->socks
->ht
, &iter
.iter
,
1292 socket
, node
.node
) {
1293 struct consumer_output
*saved_output
;
1294 struct ltt_kernel_channel
*chan
;
1297 * Temporarly switch consumer output for our snapshot output. As long
1298 * as the session lock is taken, this is safe.
1300 saved_output
= ksess
->consumer
;
1301 ksess
->consumer
= output
->consumer
;
1303 pthread_mutex_lock(socket
->lock
);
1304 /* This stream must not be monitored by the consumer. */
1305 ret
= kernel_consumer_add_metadata(socket
, ksess
, 0);
1306 pthread_mutex_unlock(socket
->lock
);
1307 /* Put back the saved consumer output into the session. */
1308 ksess
->consumer
= saved_output
;
1310 status
= LTTNG_ERR_KERN_META_FAIL
;
1311 goto error_consumer
;
1314 /* For each channel, ask the consumer to snapshot it. */
1315 cds_list_for_each_entry(chan
, &ksess
->channel_list
.head
, list
) {
1316 status
= consumer_snapshot_channel(socket
, chan
->key
, output
, 0,
1317 ksess
->uid
, ksess
->gid
,
1318 DEFAULT_KERNEL_TRACE_DIR
, wait
,
1319 nb_packets_per_stream
,
1321 if (status
!= LTTNG_OK
) {
1322 (void) kernel_consumer_destroy_metadata(socket
,
1324 goto error_consumer
;
1328 /* Snapshot metadata, */
1329 status
= consumer_snapshot_channel(socket
, ksess
->metadata
->key
, output
,
1330 1, ksess
->uid
, ksess
->gid
,
1331 DEFAULT_KERNEL_TRACE_DIR
, wait
, 0,
1333 if (status
!= LTTNG_OK
) {
1334 goto error_consumer
;
1338 * The metadata snapshot is done, ask the consumer to destroy it since
1339 * it's not monitored on the consumer side.
1341 (void) kernel_consumer_destroy_metadata(socket
, ksess
->metadata
);
1345 /* Close newly opened metadata stream. It's now on the consumer side. */
1346 err
= close(ksess
->metadata_stream_fd
);
1348 PERROR("close snapshot kernel");
1352 trace_kernel_destroy_metadata(ksess
->metadata
);
1354 /* Restore metadata state.*/
1355 ksess
->metadata
= saved_metadata
;
1356 ksess
->metadata_stream_fd
= saved_metadata_fd
;
1358 session_put(session
);
1365 * Get the syscall mask array from the kernel tracer.
1367 * Return 0 on success else a negative value. In both case, syscall_mask should
1370 int kernel_syscall_mask(int chan_fd
, char **syscall_mask
, uint32_t *nr_bits
)
1372 assert(syscall_mask
);
1375 return kernctl_syscall_mask(chan_fd
, syscall_mask
, nr_bits
);
1379 * Check for the support of the RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS via abi
1382 * Return 1 on success, 0 when feature is not supported, negative value in case
1385 int kernel_supports_ring_buffer_snapshot_sample_positions(int tracer_fd
)
1387 int ret
= 0; // Not supported by default
1388 struct lttng_kernel_tracer_abi_version abi
;
1390 ret
= kernctl_tracer_abi_version(tracer_fd
, &abi
);
1392 ERR("Failed to retrieve lttng-modules ABI version");
1397 * RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in 2.3
1399 if (abi
.major
>= 2 && abi
.minor
>= 3) {
1411 * Rotate a kernel session.
1413 * Return LTTNG_OK on success or else an LTTng error code.
1415 enum lttng_error_code
kernel_rotate_session(struct ltt_session
*session
)
1418 enum lttng_error_code status
= LTTNG_OK
;
1419 struct consumer_socket
*socket
;
1420 struct lttng_ht_iter iter
;
1421 struct ltt_kernel_session
*ksess
= session
->kernel_session
;
1424 assert(ksess
->consumer
);
1426 DBG("Rotate kernel session %s started (session %" PRIu64
")",
1427 session
->name
, session
->id
);
1432 * Note that this loop will end after one iteration given that there is
1433 * only one kernel consumer.
1435 cds_lfht_for_each_entry(ksess
->consumer
->socks
->ht
, &iter
.iter
,
1436 socket
, node
.node
) {
1437 struct ltt_kernel_channel
*chan
;
1439 /* For each channel, ask the consumer to rotate it. */
1440 cds_list_for_each_entry(chan
, &ksess
->channel_list
.head
, list
) {
1441 DBG("Rotate kernel channel %" PRIu64
", session %s",
1442 chan
->key
, session
->name
);
1443 ret
= consumer_rotate_channel(socket
, chan
->key
,
1444 ksess
->uid
, ksess
->gid
, ksess
->consumer
,
1445 ksess
->consumer
->domain_subdir
,
1446 /* is_metadata_channel */ false,
1447 session
->current_archive_id
);
1449 status
= LTTNG_ERR_KERN_CONSUMER_FAIL
;
1455 * Rotate the metadata channel.
1457 ret
= consumer_rotate_channel(socket
, ksess
->metadata
->key
,
1458 ksess
->uid
, ksess
->gid
, ksess
->consumer
,
1459 ksess
->consumer
->domain_subdir
,
1460 /* is_metadata_channel */ true,
1461 session
->current_archive_id
);
1463 status
= LTTNG_ERR_KERN_CONSUMER_FAIL
;