2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
4 * SPDX-License-Identifier: GPL-2.0-only
15 #include <sys/types.h>
17 #include <common/common.h>
18 #include <common/hashtable/utils.h>
19 #include <common/trace-chunk.h>
20 #include <common/kernel-ctl/kernel-ctl.h>
21 #include <common/kernel-ctl/kernel-ioctl.h>
22 #include <common/sessiond-comm/sessiond-comm.h>
23 #include <common/tracker.h>
24 #include <common/utils.h>
25 #include <lttng/event.h>
26 #include <lttng/lttng-error.h>
27 #include <lttng/tracker.h>
29 #include <lttng/userspace-probe.h>
30 #include <lttng/userspace-probe-internal.h>
31 #include <lttng/condition/on-event.h>
32 #include <lttng/condition/on-event-internal.h>
33 #include <lttng/event-rule/event-rule.h>
34 #include <lttng/event-rule/event-rule-internal.h>
35 #include <lttng/event-rule/userspace-probe-internal.h>
37 #include "event-notifier-error-accounting.h"
38 #include "lttng-sessiond.h"
39 #include "lttng-syscall.h"
40 #include "condition-internal.h"
43 #include "kernel-consumer.h"
44 #include "kern-modules.h"
45 #include "sessiond-config.h"
50 #include "notification-thread-commands.h"
53 * Key used to reference a channel between the sessiond and the consumer. This
54 * is only read and updated with the session_list lock held.
56 static uint64_t next_kernel_channel_key
;
58 static const char *module_proc_lttng
= "/proc/lttng";
60 static int kernel_tracer_fd
= -1;
61 static int kernel_tracer_event_notifier_group_fd
= -1;
62 static int kernel_tracer_event_notifier_group_notification_fd
= -1;
63 static struct cds_lfht
*kernel_token_to_event_notifier_rule_ht
;
66 * Add context on a kernel channel.
68 * Assumes the ownership of ctx.
70 int kernel_add_channel_context(struct ltt_kernel_channel
*chan
,
71 struct ltt_kernel_context
*ctx
)
78 DBG("Adding context to channel %s", chan
->channel
->name
);
79 ret
= kernctl_add_context(chan
->fd
, &ctx
->ctx
);
83 /* Exists but not available for this kernel */
84 ret
= LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE
;
87 /* If EEXIST, we just ignore the error */
91 PERROR("add context ioctl");
92 ret
= LTTNG_ERR_KERN_CONTEXT_FAIL
;
99 cds_list_add_tail(&ctx
->list
, &chan
->ctx_list
);
104 trace_kernel_destroy_context(ctx
);
110 * Create a new kernel session, register it to the kernel tracer and add it to
111 * the session daemon session.
113 int kernel_create_session(struct ltt_session
*session
)
116 struct ltt_kernel_session
*lks
;
120 /* Allocate data structure */
121 lks
= trace_kernel_create_session();
127 /* Kernel tracer session creation */
128 ret
= kernctl_create_session(kernel_tracer_fd
);
130 PERROR("ioctl kernel create session");
135 /* Prevent fd duplication after execlp() */
136 ret
= fcntl(lks
->fd
, F_SETFD
, FD_CLOEXEC
);
138 PERROR("fcntl session fd");
141 lks
->id
= session
->id
;
142 lks
->consumer_fds_sent
= 0;
143 session
->kernel_session
= lks
;
145 DBG("Kernel session created (fd: %d)", lks
->fd
);
148 * This is necessary since the creation time is present in the session
149 * name when it is generated.
151 if (session
->has_auto_generated_name
) {
152 ret
= kernctl_session_set_name(lks
->fd
, DEFAULT_SESSION_NAME
);
154 ret
= kernctl_session_set_name(lks
->fd
, session
->name
);
157 WARN("Could not set kernel session name for session %" PRIu64
" name: %s",
158 session
->id
, session
->name
);
161 ret
= kernctl_session_set_creation_time(lks
->fd
, session
->creation_time
);
163 WARN("Could not set kernel session creation time for session %" PRIu64
" name: %s",
164 session
->id
, session
->name
);
171 trace_kernel_destroy_session(lks
);
172 trace_kernel_free_session(lks
);
178 * Create a kernel channel, register it to the kernel tracer and add it to the
181 int kernel_create_channel(struct ltt_kernel_session
*session
,
182 struct lttng_channel
*chan
)
185 struct ltt_kernel_channel
*lkc
;
190 /* Allocate kernel channel */
191 lkc
= trace_kernel_create_channel(chan
);
196 DBG3("Kernel create channel %s with attr: %d, %" PRIu64
", %" PRIu64
", %u, %u, %d, %d",
197 chan
->name
, lkc
->channel
->attr
.overwrite
,
198 lkc
->channel
->attr
.subbuf_size
, lkc
->channel
->attr
.num_subbuf
,
199 lkc
->channel
->attr
.switch_timer_interval
, lkc
->channel
->attr
.read_timer_interval
,
200 lkc
->channel
->attr
.live_timer_interval
, lkc
->channel
->attr
.output
);
202 /* Kernel tracer channel creation */
203 ret
= kernctl_create_channel(session
->fd
, &lkc
->channel
->attr
);
205 PERROR("ioctl kernel create channel");
209 /* Setup the channel fd */
211 /* Prevent fd duplication after execlp() */
212 ret
= fcntl(lkc
->fd
, F_SETFD
, FD_CLOEXEC
);
214 PERROR("fcntl session fd");
217 /* Add channel to session */
218 cds_list_add(&lkc
->list
, &session
->channel_list
.head
);
219 session
->channel_count
++;
220 lkc
->session
= session
;
221 lkc
->key
= ++next_kernel_channel_key
;
223 DBG("Kernel channel %s created (fd: %d, key: %" PRIu64
")",
224 lkc
->channel
->name
, lkc
->fd
, lkc
->key
);
237 * Create a kernel event notifier group, register it to the kernel tracer and
238 * add it to the kernel session.
240 static int kernel_create_event_notifier_group(int *event_notifier_group_fd
)
245 assert(event_notifier_group_fd
);
247 /* Kernel event notifier group creation. */
248 ret
= kernctl_create_event_notifier_group(kernel_tracer_fd
);
250 PERROR("Failed to create kernel event notifier group");
257 /* Prevent fd duplication after execlp(). */
258 ret
= fcntl(local_fd
, F_SETFD
, FD_CLOEXEC
);
260 PERROR("Failed to set FD_CLOEXEC on kernel event notifier group file descriptor: fd = %d",
265 DBG("Created kernel event notifier group: fd = %d", local_fd
);
266 *event_notifier_group_fd
= local_fd
;
271 ret
= close(local_fd
);
273 PERROR("Failed to close kernel event notifier group file descriptor: fd = %d",
282 * Compute the offset of the instrumentation byte in the binary based on the
283 * function probe location using the ELF lookup method.
285 * Returns 0 on success and set the offset out parameter to the offset of the
287 * Returns -1 on error
290 int extract_userspace_probe_offset_function_elf(
291 const struct lttng_userspace_probe_location
*probe_location
,
292 uid_t uid
, gid_t gid
, uint64_t *offset
)
296 const char *symbol
= NULL
;
297 const struct lttng_userspace_probe_location_lookup_method
*lookup
= NULL
;
298 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type
;
300 assert(lttng_userspace_probe_location_get_type(probe_location
) ==
301 LTTNG_USERSPACE_PROBE_LOCATION_TYPE_FUNCTION
);
303 lookup
= lttng_userspace_probe_location_get_lookup_method(
311 lttng_userspace_probe_location_lookup_method_get_type(lookup
);
313 assert(lookup_method_type
==
314 LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF
);
316 symbol
= lttng_userspace_probe_location_function_get_function_name(
323 fd
= lttng_userspace_probe_location_function_get_binary_fd(probe_location
);
329 ret
= run_as_extract_elf_symbol_offset(fd
, symbol
, uid
, gid
, offset
);
331 DBG("userspace probe offset calculation failed for "
332 "function %s", symbol
);
336 DBG("userspace probe elf offset for %s is 0x%jd", symbol
, (intmax_t)(*offset
));
342 * Compute the offsets of the instrumentation bytes in the binary based on the
343 * tracepoint probe location using the SDT lookup method. This function
344 * allocates the offsets buffer, the caller must free it.
346 * Returns 0 on success and set the offset out parameter to the offsets of the
348 * Returns -1 on error.
351 int extract_userspace_probe_offset_tracepoint_sdt(
352 const struct lttng_userspace_probe_location
*probe_location
,
353 uid_t uid
, gid_t gid
, uint64_t **offsets
,
354 uint32_t *offsets_count
)
356 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type
;
357 const struct lttng_userspace_probe_location_lookup_method
*lookup
= NULL
;
358 const char *probe_name
= NULL
, *provider_name
= NULL
;
362 assert(lttng_userspace_probe_location_get_type(probe_location
) ==
363 LTTNG_USERSPACE_PROBE_LOCATION_TYPE_TRACEPOINT
);
365 lookup
= lttng_userspace_probe_location_get_lookup_method(probe_location
);
372 lttng_userspace_probe_location_lookup_method_get_type(lookup
);
374 assert(lookup_method_type
==
375 LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT
);
378 probe_name
= lttng_userspace_probe_location_tracepoint_get_probe_name(
385 provider_name
= lttng_userspace_probe_location_tracepoint_get_provider_name(
387 if (!provider_name
) {
392 fd
= lttng_userspace_probe_location_tracepoint_get_binary_fd(probe_location
);
398 ret
= run_as_extract_sdt_probe_offsets(fd
, provider_name
, probe_name
,
399 uid
, gid
, offsets
, offsets_count
);
401 DBG("userspace probe offset calculation failed for sdt "
402 "probe %s:%s", provider_name
, probe_name
);
406 if (*offsets_count
== 0) {
407 DBG("no userspace probe offset found");
411 DBG("%u userspace probe SDT offsets found for %s:%s at:",
412 *offsets_count
, provider_name
, probe_name
);
413 for (i
= 0; i
< *offsets_count
; i
++) {
414 DBG("\t0x%jd", (intmax_t)((*offsets
)[i
]));
421 int userspace_probe_add_callsite(
422 const struct lttng_userspace_probe_location
*location
,
423 uid_t uid
, gid_t gid
, int fd
)
425 const struct lttng_userspace_probe_location_lookup_method
*lookup_method
= NULL
;
426 enum lttng_userspace_probe_location_lookup_method_type type
;
429 lookup_method
= lttng_userspace_probe_location_get_lookup_method(location
);
430 if (!lookup_method
) {
435 type
= lttng_userspace_probe_location_lookup_method_get_type(lookup_method
);
437 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF
:
439 struct lttng_kernel_event_callsite callsite
;
442 ret
= extract_userspace_probe_offset_function_elf(location
,
445 ret
= LTTNG_ERR_PROBE_LOCATION_INVAL
;
449 callsite
.u
.uprobe
.offset
= offset
;
450 ret
= kernctl_add_callsite(fd
, &callsite
);
452 WARN("Failed to add callsite to ELF userspace probe.");
453 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
458 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT
:
461 uint64_t *offsets
= NULL
;
462 uint32_t offsets_count
;
463 struct lttng_kernel_event_callsite callsite
;
466 * This call allocates the offsets buffer. This buffer must be freed
469 ret
= extract_userspace_probe_offset_tracepoint_sdt(location
,
470 uid
, gid
, &offsets
, &offsets_count
);
472 ret
= LTTNG_ERR_PROBE_LOCATION_INVAL
;
475 for (i
= 0; i
< offsets_count
; i
++) {
476 callsite
.u
.uprobe
.offset
= offsets
[i
];
477 ret
= kernctl_add_callsite(fd
, &callsite
);
479 WARN("Failed to add callsite to SDT userspace probe");
480 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
489 ret
= LTTNG_ERR_PROBE_LOCATION_INVAL
;
497 * Extract the offsets of the instrumentation point for the different lookup
501 int userspace_probe_event_add_callsites(struct lttng_event
*ev
,
502 struct ltt_kernel_session
*session
, int fd
)
505 const struct lttng_userspace_probe_location
*location
= NULL
;
508 assert(ev
->type
== LTTNG_EVENT_USERSPACE_PROBE
);
510 location
= lttng_event_get_userspace_probe_location(ev
);
516 ret
= userspace_probe_add_callsite(location
, session
->uid
, session
->gid
,
519 WARN("Failed to add callsite to userspace probe event '%s'",
528 * Extract the offsets of the instrumentation point for the different look-up
531 static int userspace_probe_event_rule_add_callsites(
532 const struct lttng_event_rule
*rule
,
533 const struct lttng_credentials
*creds
,
537 enum lttng_event_rule_status status
;
538 enum lttng_event_rule_type event_rule_type
;
539 const struct lttng_userspace_probe_location
*location
= NULL
;
544 event_rule_type
= lttng_event_rule_get_type(rule
);
545 assert(event_rule_type
== LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE
);
547 status
= lttng_event_rule_userspace_probe_get_location(rule
, &location
);
548 if (status
!= LTTNG_EVENT_RULE_STATUS_OK
|| !location
) {
553 ret
= userspace_probe_add_callsite(location
,
554 lttng_credentials_get_uid(creds
),
555 lttng_credentials_get_gid(creds
), fd
);
557 WARN("Failed to add callsite to user space probe object: fd = %d",
566 * Create a kernel event, enable it to the kernel tracer and add it to the
567 * channel event list of the kernel session.
568 * We own filter_expression and filter.
570 int kernel_create_event(struct lttng_event
*ev
,
571 struct ltt_kernel_channel
*channel
,
572 char *filter_expression
,
573 struct lttng_bytecode
*filter
)
576 enum lttng_error_code ret
;
577 struct ltt_kernel_event
*event
;
582 /* We pass ownership of filter_expression and filter */
583 ret
= trace_kernel_create_event(ev
, filter_expression
,
585 if (ret
!= LTTNG_OK
) {
589 fd
= kernctl_create_event(channel
->fd
, event
->event
);
593 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
596 WARN("Event type not implemented");
597 ret
= LTTNG_ERR_KERN_EVENT_ENOSYS
;
600 WARN("Event %s not found!", ev
->name
);
601 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
604 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
605 PERROR("create event ioctl");
610 event
->type
= ev
->type
;
612 /* Prevent fd duplication after execlp() */
613 err
= fcntl(event
->fd
, F_SETFD
, FD_CLOEXEC
);
615 PERROR("fcntl session fd");
619 err
= kernctl_filter(event
->fd
, filter
);
623 ret
= LTTNG_ERR_FILTER_NOMEM
;
626 ret
= LTTNG_ERR_FILTER_INVAL
;
633 if (ev
->type
== LTTNG_EVENT_USERSPACE_PROBE
) {
634 ret
= userspace_probe_event_add_callsites(ev
, channel
->session
,
637 goto add_callsite_error
;
641 err
= kernctl_enable(event
->fd
);
645 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
648 PERROR("enable kernel event");
649 ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
655 /* Add event to event list */
656 cds_list_add(&event
->list
, &channel
->events_list
.head
);
657 channel
->event_count
++;
659 DBG("Event %s created (fd: %d)", ev
->name
, event
->fd
);
669 closeret
= close(event
->fd
);
671 PERROR("close event fd");
681 * Disable a kernel channel.
683 int kernel_disable_channel(struct ltt_kernel_channel
*chan
)
689 ret
= kernctl_disable(chan
->fd
);
691 PERROR("disable chan ioctl");
696 DBG("Kernel channel %s disabled (fd: %d, key: %" PRIu64
")",
697 chan
->channel
->name
, chan
->fd
, chan
->key
);
706 * Enable a kernel channel.
708 int kernel_enable_channel(struct ltt_kernel_channel
*chan
)
714 ret
= kernctl_enable(chan
->fd
);
715 if (ret
< 0 && ret
!= -EEXIST
) {
716 PERROR("Enable kernel chan");
721 DBG("Kernel channel %s enabled (fd: %d, key: %" PRIu64
")",
722 chan
->channel
->name
, chan
->fd
, chan
->key
);
731 * Enable a kernel event.
733 int kernel_enable_event(struct ltt_kernel_event
*event
)
739 ret
= kernctl_enable(event
->fd
);
743 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
746 PERROR("enable kernel event");
753 DBG("Kernel event %s enabled (fd: %d)", event
->event
->name
, event
->fd
);
762 * Disable a kernel event.
764 int kernel_disable_event(struct ltt_kernel_event
*event
)
770 ret
= kernctl_disable(event
->fd
);
774 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
777 PERROR("disable kernel event");
784 DBG("Kernel event %s disabled (fd: %d)", event
->event
->name
, event
->fd
);
793 * Disable a kernel event notifier.
796 int kernel_disable_event_notifier_rule(struct ltt_kernel_event_notifier_rule
*event
)
803 cds_lfht_del(kernel_token_to_event_notifier_rule_ht
, &event
->ht_node
);
806 ret
= kernctl_disable(event
->fd
);
810 ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
813 PERROR("Failed to disable kernel event notifier: fd = %d, token = %" PRIu64
,
814 event
->fd
, event
->token
);
821 DBG("Disabled kernel event notifier: fd = %d, token = %" PRIu64
,
822 event
->fd
, event
->token
);
829 struct process_attr_tracker
*_kernel_get_process_attr_tracker(
830 struct ltt_kernel_session
*session
,
831 enum lttng_process_attr process_attr
)
833 switch (process_attr
) {
834 case LTTNG_PROCESS_ATTR_PROCESS_ID
:
835 return session
->tracker_pid
;
836 case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID
:
837 return session
->tracker_vpid
;
838 case LTTNG_PROCESS_ATTR_USER_ID
:
839 return session
->tracker_uid
;
840 case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID
:
841 return session
->tracker_vuid
;
842 case LTTNG_PROCESS_ATTR_GROUP_ID
:
843 return session
->tracker_gid
;
844 case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID
:
845 return session
->tracker_vgid
;
851 const struct process_attr_tracker
*kernel_get_process_attr_tracker(
852 struct ltt_kernel_session
*session
,
853 enum lttng_process_attr process_attr
)
855 return (const struct process_attr_tracker
*)
856 _kernel_get_process_attr_tracker(session
, process_attr
);
859 enum lttng_error_code
kernel_process_attr_tracker_set_tracking_policy(
860 struct ltt_kernel_session
*session
,
861 enum lttng_process_attr process_attr
,
862 enum lttng_tracking_policy policy
)
865 enum lttng_error_code ret_code
= LTTNG_OK
;
866 struct process_attr_tracker
*tracker
=
867 _kernel_get_process_attr_tracker(session
, process_attr
);
868 enum lttng_tracking_policy previous_policy
;
871 ret_code
= LTTNG_ERR_INVALID
;
875 previous_policy
= process_attr_tracker_get_tracking_policy(tracker
);
876 ret
= process_attr_tracker_set_tracking_policy(tracker
, policy
);
878 ret_code
= LTTNG_ERR_UNK
;
882 if (previous_policy
== policy
) {
887 case LTTNG_TRACKING_POLICY_INCLUDE_ALL
:
888 if (process_attr
== LTTNG_PROCESS_ATTR_PROCESS_ID
) {
890 * Maintain a special case for the process ID process
891 * attribute tracker as it was the only supported
892 * attribute prior to 2.12.
894 ret
= kernctl_track_pid(session
->fd
, -1);
896 ret
= kernctl_track_id(session
->fd
, process_attr
, -1);
899 case LTTNG_TRACKING_POLICY_EXCLUDE_ALL
:
900 case LTTNG_TRACKING_POLICY_INCLUDE_SET
:
902 if (process_attr
== LTTNG_PROCESS_ATTR_PROCESS_ID
) {
904 * Maintain a special case for the process ID process
905 * attribute tracker as it was the only supported
906 * attribute prior to 2.12.
908 ret
= kernctl_untrack_pid(session
->fd
, -1);
910 ret
= kernctl_untrack_id(session
->fd
, process_attr
, -1);
916 /* kern-ctl error handling */
922 ret_code
= LTTNG_ERR_INVALID
;
925 ret_code
= LTTNG_ERR_NOMEM
;
928 ret_code
= LTTNG_ERR_PROCESS_ATTR_EXISTS
;
931 ret_code
= LTTNG_ERR_UNK
;
938 enum lttng_error_code
kernel_process_attr_tracker_inclusion_set_add_value(
939 struct ltt_kernel_session
*session
,
940 enum lttng_process_attr process_attr
,
941 const struct process_attr_value
*value
)
943 int ret
, integral_value
;
944 enum lttng_error_code ret_code
;
945 struct process_attr_tracker
*tracker
;
946 enum process_attr_tracker_status status
;
949 * Convert process attribute tracker value to the integral
950 * representation required by the kern-ctl API.
952 switch (process_attr
) {
953 case LTTNG_PROCESS_ATTR_PROCESS_ID
:
954 case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID
:
955 integral_value
= (int) value
->value
.pid
;
957 case LTTNG_PROCESS_ATTR_USER_ID
:
958 case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID
:
959 if (value
->type
== LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME
) {
962 ret_code
= utils_user_id_from_name(
963 value
->value
.user_name
, &uid
);
964 if (ret_code
!= LTTNG_OK
) {
967 integral_value
= (int) uid
;
969 integral_value
= (int) value
->value
.uid
;
972 case LTTNG_PROCESS_ATTR_GROUP_ID
:
973 case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID
:
974 if (value
->type
== LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME
) {
977 ret_code
= utils_group_id_from_name(
978 value
->value
.group_name
, &gid
);
979 if (ret_code
!= LTTNG_OK
) {
982 integral_value
= (int) gid
;
984 integral_value
= (int) value
->value
.gid
;
988 ret_code
= LTTNG_ERR_INVALID
;
992 tracker
= _kernel_get_process_attr_tracker(session
, process_attr
);
994 ret_code
= LTTNG_ERR_INVALID
;
998 status
= process_attr_tracker_inclusion_set_add_value(tracker
, value
);
999 if (status
!= PROCESS_ATTR_TRACKER_STATUS_OK
) {
1001 case PROCESS_ATTR_TRACKER_STATUS_EXISTS
:
1002 ret_code
= LTTNG_ERR_PROCESS_ATTR_EXISTS
;
1004 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY
:
1005 ret_code
= LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY
;
1007 case PROCESS_ATTR_TRACKER_STATUS_ERROR
:
1009 ret_code
= LTTNG_ERR_UNK
;
1015 DBG("Kernel track %s %d for session id %" PRIu64
,
1016 lttng_process_attr_to_string(process_attr
),
1017 integral_value
, session
->id
);
1018 if (process_attr
== LTTNG_PROCESS_ATTR_PROCESS_ID
) {
1020 * Maintain a special case for the process ID process attribute
1021 * tracker as it was the only supported attribute prior to 2.12.
1023 ret
= kernctl_track_pid(session
->fd
, integral_value
);
1025 ret
= kernctl_track_id(
1026 session
->fd
, process_attr
, integral_value
);
1029 ret_code
= LTTNG_OK
;
1033 kernel_wait_quiescent();
1035 /* kern-ctl error handling */
1038 ret_code
= LTTNG_OK
;
1041 ret_code
= LTTNG_ERR_INVALID
;
1044 ret_code
= LTTNG_ERR_NOMEM
;
1047 ret_code
= LTTNG_ERR_PROCESS_ATTR_EXISTS
;
1050 ret_code
= LTTNG_ERR_UNK
;
1054 /* Attempt to remove the value from the tracker. */
1055 status
= process_attr_tracker_inclusion_set_remove_value(
1057 if (status
!= PROCESS_ATTR_TRACKER_STATUS_OK
) {
1058 ERR("Failed to roll-back the tracking of kernel %s process attribute %d while handling a kern-ctl error",
1059 lttng_process_attr_to_string(process_attr
),
1066 enum lttng_error_code
kernel_process_attr_tracker_inclusion_set_remove_value(
1067 struct ltt_kernel_session
*session
,
1068 enum lttng_process_attr process_attr
,
1069 const struct process_attr_value
*value
)
1071 int ret
, integral_value
;
1072 enum lttng_error_code ret_code
;
1073 struct process_attr_tracker
*tracker
;
1074 enum process_attr_tracker_status status
;
1077 * Convert process attribute tracker value to the integral
1078 * representation required by the kern-ctl API.
1080 switch (process_attr
) {
1081 case LTTNG_PROCESS_ATTR_PROCESS_ID
:
1082 case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID
:
1083 integral_value
= (int) value
->value
.pid
;
1085 case LTTNG_PROCESS_ATTR_USER_ID
:
1086 case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID
:
1087 if (value
->type
== LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME
) {
1090 ret_code
= utils_user_id_from_name(
1091 value
->value
.user_name
, &uid
);
1092 if (ret_code
!= LTTNG_OK
) {
1095 integral_value
= (int) uid
;
1097 integral_value
= (int) value
->value
.uid
;
1100 case LTTNG_PROCESS_ATTR_GROUP_ID
:
1101 case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID
:
1102 if (value
->type
== LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME
) {
1105 ret_code
= utils_group_id_from_name(
1106 value
->value
.group_name
, &gid
);
1107 if (ret_code
!= LTTNG_OK
) {
1110 integral_value
= (int) gid
;
1112 integral_value
= (int) value
->value
.gid
;
1116 ret_code
= LTTNG_ERR_INVALID
;
1120 tracker
= _kernel_get_process_attr_tracker(session
, process_attr
);
1122 ret_code
= LTTNG_ERR_INVALID
;
1126 status
= process_attr_tracker_inclusion_set_remove_value(
1128 if (status
!= PROCESS_ATTR_TRACKER_STATUS_OK
) {
1130 case PROCESS_ATTR_TRACKER_STATUS_MISSING
:
1131 ret_code
= LTTNG_ERR_PROCESS_ATTR_MISSING
;
1133 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY
:
1134 ret_code
= LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY
;
1136 case PROCESS_ATTR_TRACKER_STATUS_ERROR
:
1138 ret_code
= LTTNG_ERR_UNK
;
1144 DBG("Kernel track %s %d for session id %" PRIu64
,
1145 lttng_process_attr_to_string(process_attr
),
1146 integral_value
, session
->id
);
1147 if (process_attr
== LTTNG_PROCESS_ATTR_PROCESS_ID
) {
1149 * Maintain a special case for the process ID process attribute
1150 * tracker as it was the only supported attribute prior to 2.12.
1152 ret
= kernctl_untrack_pid(session
->fd
, integral_value
);
1154 ret
= kernctl_untrack_id(
1155 session
->fd
, process_attr
, integral_value
);
1158 ret_code
= LTTNG_OK
;
1161 kernel_wait_quiescent();
1163 /* kern-ctl error handling */
1166 ret_code
= LTTNG_OK
;
1169 ret_code
= LTTNG_ERR_INVALID
;
1172 ret_code
= LTTNG_ERR_NOMEM
;
1175 ret_code
= LTTNG_ERR_PROCESS_ATTR_MISSING
;
1178 ret_code
= LTTNG_ERR_UNK
;
1182 /* Attempt to add the value to the tracker. */
1183 status
= process_attr_tracker_inclusion_set_add_value(
1185 if (status
!= PROCESS_ATTR_TRACKER_STATUS_OK
) {
1186 ERR("Failed to roll-back the tracking of kernel %s process attribute %d while handling a kern-ctl error",
1187 lttng_process_attr_to_string(process_attr
),
1195 * Create kernel metadata, open from the kernel tracer and add it to the
1198 int kernel_open_metadata(struct ltt_kernel_session
*session
)
1201 struct ltt_kernel_metadata
*lkm
= NULL
;
1205 /* Allocate kernel metadata */
1206 lkm
= trace_kernel_create_metadata();
1211 /* Kernel tracer metadata creation */
1212 ret
= kernctl_open_metadata(session
->fd
, &lkm
->conf
->attr
);
1218 lkm
->key
= ++next_kernel_channel_key
;
1219 /* Prevent fd duplication after execlp() */
1220 ret
= fcntl(lkm
->fd
, F_SETFD
, FD_CLOEXEC
);
1222 PERROR("fcntl session fd");
1225 session
->metadata
= lkm
;
1227 DBG("Kernel metadata opened (fd: %d)", lkm
->fd
);
1232 trace_kernel_destroy_metadata(lkm
);
1238 * Start tracing session.
1240 int kernel_start_session(struct ltt_kernel_session
*session
)
1246 ret
= kernctl_start_session(session
->fd
);
1248 PERROR("ioctl start session");
1252 DBG("Kernel session started");
1261 * Make a kernel wait to make sure in-flight probe have completed.
1263 void kernel_wait_quiescent(void)
1266 int fd
= kernel_tracer_fd
;
1268 DBG("Kernel quiescent wait on %d", fd
);
1270 ret
= kernctl_wait_quiescent(fd
);
1272 PERROR("wait quiescent ioctl");
1273 ERR("Kernel quiescent wait failed");
1278 * Force flush buffer of metadata.
1280 int kernel_metadata_flush_buffer(int fd
)
1284 DBG("Kernel flushing metadata buffer on fd %d", fd
);
1286 ret
= kernctl_buffer_flush(fd
);
1288 ERR("Fail to flush metadata buffers %d (ret: %d)", fd
, ret
);
1295 * Force flush buffer for channel.
1297 int kernel_flush_buffer(struct ltt_kernel_channel
*channel
)
1300 struct ltt_kernel_stream
*stream
;
1304 DBG("Flush buffer for channel %s", channel
->channel
->name
);
1306 cds_list_for_each_entry(stream
, &channel
->stream_list
.head
, list
) {
1307 DBG("Flushing channel stream %d", stream
->fd
);
1308 ret
= kernctl_buffer_flush(stream
->fd
);
1311 ERR("Fail to flush buffer for stream %d (ret: %d)",
1320 * Stop tracing session.
1322 int kernel_stop_session(struct ltt_kernel_session
*session
)
1328 ret
= kernctl_stop_session(session
->fd
);
1333 DBG("Kernel session stopped");
1342 * Open stream of channel, register it to the kernel tracer and add it
1343 * to the stream list of the channel.
1345 * Note: given that the streams may appear in random order wrt CPU
1346 * number (e.g. cpu hotplug), the index value of the stream number in
1347 * the stream name is not necessarily linked to the CPU number.
1349 * Return the number of created stream. Else, a negative value.
1351 int kernel_open_channel_stream(struct ltt_kernel_channel
*channel
)
1354 struct ltt_kernel_stream
*lks
;
1358 while ((ret
= kernctl_create_stream(channel
->fd
)) >= 0) {
1359 lks
= trace_kernel_create_stream(channel
->channel
->name
,
1360 channel
->stream_count
);
1370 /* Prevent fd duplication after execlp() */
1371 ret
= fcntl(lks
->fd
, F_SETFD
, FD_CLOEXEC
);
1373 PERROR("fcntl session fd");
1376 lks
->tracefile_size
= channel
->channel
->attr
.tracefile_size
;
1377 lks
->tracefile_count
= channel
->channel
->attr
.tracefile_count
;
1379 /* Add stream to channel stream list */
1380 cds_list_add(&lks
->list
, &channel
->stream_list
.head
);
1381 channel
->stream_count
++;
1383 DBG("Kernel stream %s created (fd: %d, state: %d)", lks
->name
, lks
->fd
,
1387 return channel
->stream_count
;
1394 * Open the metadata stream and set it to the kernel session.
1396 int kernel_open_metadata_stream(struct ltt_kernel_session
*session
)
1402 ret
= kernctl_create_stream(session
->metadata
->fd
);
1404 PERROR("kernel create metadata stream");
1408 DBG("Kernel metadata stream created (fd: %d)", ret
);
1409 session
->metadata_stream_fd
= ret
;
1410 /* Prevent fd duplication after execlp() */
1411 ret
= fcntl(session
->metadata_stream_fd
, F_SETFD
, FD_CLOEXEC
);
1413 PERROR("fcntl session fd");
1423 * Get the event list from the kernel tracer and return the number of elements.
1425 ssize_t
kernel_list_events(struct lttng_event
**events
)
1429 size_t nbmem
, count
= 0;
1431 struct lttng_event
*elist
;
1435 fd
= kernctl_tracepoint_list(kernel_tracer_fd
);
1437 PERROR("kernel tracepoint list");
1441 fp
= fdopen(fd
, "r");
1443 PERROR("kernel tracepoint list fdopen");
1448 * Init memory size counter
1449 * See kernel-ctl.h for explanation of this value
1451 nbmem
= KERNEL_EVENT_INIT_LIST_SIZE
;
1452 elist
= zmalloc(sizeof(struct lttng_event
) * nbmem
);
1453 if (elist
== NULL
) {
1454 PERROR("alloc list events");
1459 while (fscanf(fp
, "event { name = %m[^;]; };\n", &event
) == 1) {
1460 if (count
>= nbmem
) {
1461 struct lttng_event
*new_elist
;
1464 new_nbmem
= nbmem
<< 1;
1465 DBG("Reallocating event list from %zu to %zu bytes",
1467 new_elist
= realloc(elist
, new_nbmem
* sizeof(struct lttng_event
));
1468 if (new_elist
== NULL
) {
1469 PERROR("realloc list events");
1475 /* Zero the new memory */
1476 memset(new_elist
+ nbmem
, 0,
1477 (new_nbmem
- nbmem
) * sizeof(struct lttng_event
));
1481 strncpy(elist
[count
].name
, event
, LTTNG_SYMBOL_NAME_LEN
);
1482 elist
[count
].name
[LTTNG_SYMBOL_NAME_LEN
- 1] = '\0';
1483 elist
[count
].enabled
= -1;
1489 DBG("Kernel list events done (%zu events)", count
);
1491 ret
= fclose(fp
); /* closes both fp and fd */
1507 * Get kernel version and validate it.
1509 int kernel_validate_version(struct lttng_kernel_tracer_version
*version
,
1510 struct lttng_kernel_tracer_abi_version
*abi_version
)
1514 ret
= kernctl_tracer_version(kernel_tracer_fd
, version
);
1516 ERR("Failed to retrieve the lttng-modules version");
1520 /* Validate version */
1521 if (version
->major
!= VERSION_MAJOR
) {
1522 ERR("Kernel tracer major version (%d) is not compatible with lttng-tools major version (%d)",
1523 version
->major
, VERSION_MAJOR
);
1526 ret
= kernctl_tracer_abi_version(kernel_tracer_fd
, abi_version
);
1528 ERR("Failed to retrieve lttng-modules ABI version");
1531 if (abi_version
->major
!= LTTNG_MODULES_ABI_MAJOR_VERSION
) {
1532 ERR("Kernel tracer ABI version (%d.%d) does not match the expected ABI major version (%d.*)",
1533 abi_version
->major
, abi_version
->minor
,
1534 LTTNG_MODULES_ABI_MAJOR_VERSION
);
1537 DBG2("Kernel tracer version validated (%d.%d, ABI %d.%d)",
1538 version
->major
, version
->minor
,
1539 abi_version
->major
, abi_version
->minor
);
1546 ERR("Kernel tracer version check failed; kernel tracing will not be available");
1551 * Kernel work-arounds called at the start of sessiond main().
1553 int init_kernel_workarounds(void)
1559 * boot_id needs to be read once before being used concurrently
1560 * to deal with a Linux kernel race. A fix is proposed for
1561 * upstream, but the work-around is needed for older kernels.
1563 fp
= fopen("/proc/sys/kernel/random/boot_id", "r");
1570 ret
= fread(buf
, 1, sizeof(buf
), fp
);
1572 /* Ignore error, we don't really care */
1584 * Teardown of a kernel session, keeping data required by destroy notifiers.
1586 void kernel_destroy_session(struct ltt_kernel_session
*ksess
)
1588 struct lttng_trace_chunk
*trace_chunk
;
1590 if (ksess
== NULL
) {
1591 DBG3("No kernel session when tearing down session");
1595 DBG("Tearing down kernel session");
1596 trace_chunk
= ksess
->current_trace_chunk
;
1599 * Destroy channels on the consumer if at least one FD has been sent and we
1600 * are in no output mode because the streams are in *no* monitor mode so we
1601 * have to send a command to clean them up or else they leaked.
1603 if (!ksess
->output_traces
&& ksess
->consumer_fds_sent
) {
1605 struct consumer_socket
*socket
;
1606 struct lttng_ht_iter iter
;
1608 /* For each consumer socket. */
1610 cds_lfht_for_each_entry(ksess
->consumer
->socks
->ht
, &iter
.iter
,
1611 socket
, node
.node
) {
1612 struct ltt_kernel_channel
*chan
;
1614 /* For each channel, ask the consumer to destroy it. */
1615 cds_list_for_each_entry(chan
, &ksess
->channel_list
.head
, list
) {
1616 ret
= kernel_consumer_destroy_channel(socket
, chan
);
1618 /* Consumer is probably dead. Use next socket. */
1626 /* Close any relayd session */
1627 consumer_output_send_destroy_relayd(ksess
->consumer
);
1629 trace_kernel_destroy_session(ksess
);
1630 lttng_trace_chunk_put(trace_chunk
);
1633 /* Teardown of data required by destroy notifiers. */
1634 void kernel_free_session(struct ltt_kernel_session
*ksess
)
1636 if (ksess
== NULL
) {
1639 trace_kernel_free_session(ksess
);
1643 * Destroy a kernel channel object. It does not do anything on the tracer side.
1645 void kernel_destroy_channel(struct ltt_kernel_channel
*kchan
)
1647 struct ltt_kernel_session
*ksess
= NULL
;
1650 assert(kchan
->channel
);
1652 DBG3("Kernel destroy channel %s", kchan
->channel
->name
);
1654 /* Update channel count of associated session. */
1655 if (kchan
->session
) {
1656 /* Keep pointer reference so we can update it after the destroy. */
1657 ksess
= kchan
->session
;
1660 trace_kernel_destroy_channel(kchan
);
1663 * At this point the kernel channel is not visible anymore. This is safe
1664 * since in order to work on a visible kernel session, the tracing session
1665 * lock (ltt_session.lock) MUST be acquired.
1668 ksess
->channel_count
--;
1673 * Take a snapshot for a given kernel session.
1675 * Return LTTNG_OK on success or else return a LTTNG_ERR code.
1677 enum lttng_error_code
kernel_snapshot_record(
1678 struct ltt_kernel_session
*ksess
,
1679 const struct consumer_output
*output
, int wait
,
1680 uint64_t nb_packets_per_stream
)
1682 int err
, ret
, saved_metadata_fd
;
1683 enum lttng_error_code status
= LTTNG_OK
;
1684 struct consumer_socket
*socket
;
1685 struct lttng_ht_iter iter
;
1686 struct ltt_kernel_metadata
*saved_metadata
;
1687 char *trace_path
= NULL
;
1688 size_t consumer_path_offset
= 0;
1691 assert(ksess
->consumer
);
1694 DBG("Kernel snapshot record started");
1696 /* Save current metadata since the following calls will change it. */
1697 saved_metadata
= ksess
->metadata
;
1698 saved_metadata_fd
= ksess
->metadata_stream_fd
;
1702 ret
= kernel_open_metadata(ksess
);
1704 status
= LTTNG_ERR_KERN_META_FAIL
;
1708 ret
= kernel_open_metadata_stream(ksess
);
1710 status
= LTTNG_ERR_KERN_META_FAIL
;
1711 goto error_open_stream
;
1714 trace_path
= setup_channel_trace_path(ksess
->consumer
,
1715 DEFAULT_KERNEL_TRACE_DIR
, &consumer_path_offset
);
1717 status
= LTTNG_ERR_INVALID
;
1720 /* Send metadata to consumer and snapshot everything. */
1721 cds_lfht_for_each_entry(output
->socks
->ht
, &iter
.iter
,
1722 socket
, node
.node
) {
1723 struct ltt_kernel_channel
*chan
;
1725 pthread_mutex_lock(socket
->lock
);
1726 /* This stream must not be monitored by the consumer. */
1727 ret
= kernel_consumer_add_metadata(socket
, ksess
, 0);
1728 pthread_mutex_unlock(socket
->lock
);
1730 status
= LTTNG_ERR_KERN_META_FAIL
;
1731 goto error_consumer
;
1734 /* For each channel, ask the consumer to snapshot it. */
1735 cds_list_for_each_entry(chan
, &ksess
->channel_list
.head
, list
) {
1736 status
= consumer_snapshot_channel(socket
, chan
->key
, output
, 0,
1737 ksess
->uid
, ksess
->gid
,
1738 &trace_path
[consumer_path_offset
], wait
,
1739 nb_packets_per_stream
);
1740 if (status
!= LTTNG_OK
) {
1741 (void) kernel_consumer_destroy_metadata(socket
,
1743 goto error_consumer
;
1747 /* Snapshot metadata, */
1748 status
= consumer_snapshot_channel(socket
, ksess
->metadata
->key
, output
,
1749 1, ksess
->uid
, ksess
->gid
, &trace_path
[consumer_path_offset
],
1751 if (status
!= LTTNG_OK
) {
1752 goto error_consumer
;
1756 * The metadata snapshot is done, ask the consumer to destroy it since
1757 * it's not monitored on the consumer side.
1759 (void) kernel_consumer_destroy_metadata(socket
, ksess
->metadata
);
1763 /* Close newly opened metadata stream. It's now on the consumer side. */
1764 err
= close(ksess
->metadata_stream_fd
);
1766 PERROR("close snapshot kernel");
1770 trace_kernel_destroy_metadata(ksess
->metadata
);
1772 /* Restore metadata state.*/
1773 ksess
->metadata
= saved_metadata
;
1774 ksess
->metadata_stream_fd
= saved_metadata_fd
;
1781 * Get the syscall mask array from the kernel tracer.
1783 * Return 0 on success else a negative value. In both case, syscall_mask should
1786 int kernel_syscall_mask(int chan_fd
, char **syscall_mask
, uint32_t *nr_bits
)
1788 assert(syscall_mask
);
1791 return kernctl_syscall_mask(chan_fd
, syscall_mask
, nr_bits
);
1795 int kernel_tracer_abi_greater_or_equal(unsigned int major
, unsigned int minor
)
1798 struct lttng_kernel_tracer_abi_version abi
;
1800 ret
= kernctl_tracer_abi_version(kernel_tracer_fd
, &abi
);
1802 ERR("Failed to retrieve lttng-modules ABI version");
1806 ret
= abi
.major
> major
|| (abi
.major
== major
&& abi
.minor
>= minor
);
1812 * Check for the support of the RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS via abi
1815 * Return 1 on success, 0 when feature is not supported, negative value in case
1818 int kernel_supports_ring_buffer_snapshot_sample_positions(void)
1821 * RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in 2.3
1823 return kernel_tracer_abi_greater_or_equal(2, 3);
1827 * Check for the support of the packet sequence number via abi version number.
1829 * Return 1 on success, 0 when feature is not supported, negative value in case
1832 int kernel_supports_ring_buffer_packet_sequence_number(void)
1835 * Packet sequence number was introduced in LTTng 2.8,
1836 * lttng-modules ABI 2.1.
1838 return kernel_tracer_abi_greater_or_equal(2, 1);
1842 * Check for the support of event notifiers via abi version number.
1844 * Return 1 on success, 0 when feature is not supported, negative value in case
1847 int kernel_supports_event_notifiers(void)
1850 * Event notifiers were introduced in LTTng 2.13, lttng-modules ABI 2.6.
1852 return kernel_tracer_abi_greater_or_equal(2, 6);
1856 * Rotate a kernel session.
1858 * Return LTTNG_OK on success or else an LTTng error code.
1860 enum lttng_error_code
kernel_rotate_session(struct ltt_session
*session
)
1863 enum lttng_error_code status
= LTTNG_OK
;
1864 struct consumer_socket
*socket
;
1865 struct lttng_ht_iter iter
;
1866 struct ltt_kernel_session
*ksess
= session
->kernel_session
;
1869 assert(ksess
->consumer
);
1871 DBG("Rotate kernel session %s started (session %" PRIu64
")",
1872 session
->name
, session
->id
);
1877 * Note that this loop will end after one iteration given that there is
1878 * only one kernel consumer.
1880 cds_lfht_for_each_entry(ksess
->consumer
->socks
->ht
, &iter
.iter
,
1881 socket
, node
.node
) {
1882 struct ltt_kernel_channel
*chan
;
1884 /* For each channel, ask the consumer to rotate it. */
1885 cds_list_for_each_entry(chan
, &ksess
->channel_list
.head
, list
) {
1886 DBG("Rotate kernel channel %" PRIu64
", session %s",
1887 chan
->key
, session
->name
);
1888 ret
= consumer_rotate_channel(socket
, chan
->key
,
1889 ksess
->uid
, ksess
->gid
, ksess
->consumer
,
1890 /* is_metadata_channel */ false);
1892 status
= LTTNG_ERR_ROTATION_FAIL_CONSUMER
;
1898 * Rotate the metadata channel.
1900 ret
= consumer_rotate_channel(socket
, ksess
->metadata
->key
,
1901 ksess
->uid
, ksess
->gid
, ksess
->consumer
,
1902 /* is_metadata_channel */ true);
1904 status
= LTTNG_ERR_ROTATION_FAIL_CONSUMER
;
1914 enum lttng_error_code
kernel_create_channel_subdirectories(
1915 const struct ltt_kernel_session
*ksess
)
1917 enum lttng_error_code ret
= LTTNG_OK
;
1918 enum lttng_trace_chunk_status chunk_status
;
1921 assert(ksess
->current_trace_chunk
);
1924 * Create the index subdirectory which will take care
1925 * of implicitly creating the channel's path.
1927 chunk_status
= lttng_trace_chunk_create_subdirectory(
1928 ksess
->current_trace_chunk
,
1929 DEFAULT_KERNEL_TRACE_DIR
"/" DEFAULT_INDEX_DIR
);
1930 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
1931 ret
= LTTNG_ERR_CREATE_DIR_FAIL
;
1940 * Setup necessary data for kernel tracer action.
1943 int init_kernel_tracer(void)
1946 bool is_root
= !getuid();
1948 /* Modprobe lttng kernel modules */
1949 ret
= modprobe_lttng_control();
1954 /* Open debugfs lttng */
1955 kernel_tracer_fd
= open(module_proc_lttng
, O_RDWR
);
1956 if (kernel_tracer_fd
< 0) {
1957 DBG("Failed to open %s", module_proc_lttng
);
1961 /* Validate kernel version */
1962 ret
= kernel_validate_version(&kernel_tracer_version
,
1963 &kernel_tracer_abi_version
);
1968 ret
= modprobe_lttng_data();
1973 ret
= kernel_supports_ring_buffer_snapshot_sample_positions();
1978 WARN("Kernel tracer does not support buffer monitoring. "
1979 "The monitoring timer of channels in the kernel domain "
1980 "will be set to 0 (disabled).");
1983 ret
= kernel_supports_event_notifiers();
1985 ERR("Failed to check for kernel tracer event notifier support");
1988 ret
= kernel_create_event_notifier_group(&kernel_tracer_event_notifier_group_fd
);
1990 /* This is not fatal. */
1991 WARN("Failed to create kernel event notifier group");
1992 kernel_tracer_event_notifier_group_fd
= -1;
1994 enum event_notifier_error_accounting_status error_accounting_status
;
1995 enum lttng_error_code error_code_ret
=
1996 kernel_create_event_notifier_group_notification_fd(
1997 &kernel_tracer_event_notifier_group_notification_fd
);
1999 if (error_code_ret
!= LTTNG_OK
) {
2003 error_accounting_status
= event_notifier_error_accounting_register_kernel(
2004 kernel_tracer_event_notifier_group_fd
);
2005 if (error_accounting_status
!= EVENT_NOTIFIER_ERROR_ACCOUNTING_STATUS_OK
) {
2006 ERR("Failed to initialize event notifier error accounting for kernel tracer");
2007 error_code_ret
= LTTNG_ERR_EVENT_NOTIFIER_ERROR_ACCOUNTING
;
2011 kernel_token_to_event_notifier_rule_ht
= cds_lfht_new(
2012 DEFAULT_HT_SIZE
, 1, 0,
2013 CDS_LFHT_AUTO_RESIZE
| CDS_LFHT_ACCOUNTING
,
2015 if (!kernel_token_to_event_notifier_rule_ht
) {
2016 goto error_token_ht
;
2020 DBG("Kernel tracer initialized: kernel tracer fd = %d, event notifier group fd = %d, event notifier group notification fd = %d",
2021 kernel_tracer_fd
, kernel_tracer_event_notifier_group_fd
,
2022 kernel_tracer_event_notifier_group_notification_fd
);
2024 ret
= syscall_init_table(kernel_tracer_fd
);
2026 ERR("Unable to populate syscall table. Syscall tracing won't "
2027 "work for this session daemon.");
2033 modprobe_remove_lttng_control();
2034 ret
= close(kernel_tracer_fd
);
2036 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2039 kernel_tracer_fd
= -1;
2040 return LTTNG_ERR_KERN_VERSION
;
2044 ret
= close(kernel_tracer_event_notifier_group_notification_fd
);
2046 PERROR("Failed to close kernel tracer event notifier group notification file descriptor: fd = %d",
2047 kernel_tracer_event_notifier_group_notification_fd
);
2051 ret
= close(kernel_tracer_event_notifier_group_fd
);
2053 PERROR("Failed to close kernel tracer event notifier group file descriptor: fd = %d",
2054 kernel_tracer_event_notifier_group_fd
);
2057 ret
= close(kernel_tracer_fd
);
2059 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2064 modprobe_remove_lttng_control();
2067 WARN("No kernel tracer available");
2068 kernel_tracer_fd
= -1;
2070 return LTTNG_ERR_NEED_ROOT_SESSIOND
;
2072 return LTTNG_ERR_KERN_NA
;
2077 void cleanup_kernel_tracer(void)
2079 DBG2("Closing kernel event notifier group notification file descriptor");
2080 if (kernel_tracer_event_notifier_group_notification_fd
>= 0) {
2081 int ret
= notification_thread_command_remove_tracer_event_source(
2082 notification_thread_handle
,
2083 kernel_tracer_event_notifier_group_notification_fd
);
2084 if (ret
!= LTTNG_OK
) {
2085 ERR("Failed to remove kernel event notifier notification from notification thread");
2088 ret
= close(kernel_tracer_event_notifier_group_notification_fd
);
2090 PERROR("Failed to close kernel event notifier group notification file descriptor: fd = %d",
2091 kernel_tracer_event_notifier_group_notification_fd
);
2094 kernel_tracer_event_notifier_group_notification_fd
= -1;
2097 if (kernel_token_to_event_notifier_rule_ht
) {
2098 const int ret
= cds_lfht_destroy(
2099 kernel_token_to_event_notifier_rule_ht
, NULL
);
2103 DBG2("Closing kernel event notifier group file descriptor");
2104 if (kernel_tracer_event_notifier_group_fd
>= 0) {
2105 const int ret
= close(kernel_tracer_event_notifier_group_fd
);
2108 PERROR("Failed to close kernel event notifier group file descriptor: fd = %d",
2109 kernel_tracer_event_notifier_group_fd
);
2112 kernel_tracer_event_notifier_group_fd
= -1;
2115 DBG2("Closing kernel fd");
2116 if (kernel_tracer_fd
>= 0) {
2117 const int ret
= close(kernel_tracer_fd
);
2120 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2124 kernel_tracer_fd
= -1;
2127 DBG("Unloading kernel modules");
2128 modprobe_remove_lttng_all();
2129 free(syscall_table
);
2133 bool kernel_tracer_is_initialized(void)
2135 return kernel_tracer_fd
>= 0;
2139 * Clear a kernel session.
2141 * Return LTTNG_OK on success or else an LTTng error code.
2143 enum lttng_error_code
kernel_clear_session(struct ltt_session
*session
)
2146 enum lttng_error_code status
= LTTNG_OK
;
2147 struct consumer_socket
*socket
;
2148 struct lttng_ht_iter iter
;
2149 struct ltt_kernel_session
*ksess
= session
->kernel_session
;
2152 assert(ksess
->consumer
);
2154 DBG("Clear kernel session %s (session %" PRIu64
")",
2155 session
->name
, session
->id
);
2159 if (ksess
->active
) {
2160 ERR("Expecting inactive session %s (%" PRIu64
")", session
->name
, session
->id
);
2161 status
= LTTNG_ERR_FATAL
;
2166 * Note that this loop will end after one iteration given that there is
2167 * only one kernel consumer.
2169 cds_lfht_for_each_entry(ksess
->consumer
->socks
->ht
, &iter
.iter
,
2170 socket
, node
.node
) {
2171 struct ltt_kernel_channel
*chan
;
2173 /* For each channel, ask the consumer to clear it. */
2174 cds_list_for_each_entry(chan
, &ksess
->channel_list
.head
, list
) {
2175 DBG("Clear kernel channel %" PRIu64
", session %s",
2176 chan
->key
, session
->name
);
2177 ret
= consumer_clear_channel(socket
, chan
->key
);
2183 if (!ksess
->metadata
) {
2185 * Nothing to do for the metadata.
2186 * This is a snapshot session.
2187 * The metadata is genererated on the fly.
2193 * Clear the metadata channel.
2194 * Metadata channel is not cleared per se but we still need to
2195 * perform a rotation operation on it behind the scene.
2197 ret
= consumer_clear_channel(socket
, ksess
->metadata
->key
);
2206 case LTTCOMM_CONSUMERD_RELAYD_CLEAR_DISALLOWED
:
2207 status
= LTTNG_ERR_CLEAR_RELAY_DISALLOWED
;
2210 status
= LTTNG_ERR_CLEAR_FAIL_CONSUMER
;
2218 enum lttng_error_code
kernel_create_event_notifier_group_notification_fd(
2219 int *event_notifier_group_notification_fd
)
2221 int local_fd
= -1, ret
;
2222 enum lttng_error_code error_code_ret
;
2224 assert(event_notifier_group_notification_fd
);
2226 ret
= kernctl_create_event_notifier_group_notification_fd(
2227 kernel_tracer_event_notifier_group_fd
);
2229 PERROR("Failed to create kernel event notifier group notification file descriptor");
2230 error_code_ret
= LTTNG_ERR_EVENT_NOTIFIER_GROUP_NOTIFICATION_FD
;
2236 /* Prevent fd duplication after execlp(). */
2237 ret
= fcntl(local_fd
, F_SETFD
, FD_CLOEXEC
);
2239 PERROR("Failed to set FD_CLOEXEC on kernel event notifier group notification file descriptor: fd = %d",
2241 error_code_ret
= LTTNG_ERR_EVENT_NOTIFIER_GROUP_NOTIFICATION_FD
;
2245 DBG("Created kernel notifier group notification file descriptor: fd = %d",
2247 error_code_ret
= LTTNG_OK
;
2248 *event_notifier_group_notification_fd
= local_fd
;
2252 if (local_fd
>= 0) {
2253 ret
= close(local_fd
);
2255 PERROR("Failed to close kernel event notifier group notification file descriptor: fd = %d",
2260 return error_code_ret
;
2263 enum lttng_error_code
kernel_destroy_event_notifier_group_notification_fd(
2264 int event_notifier_group_notification_fd
)
2266 enum lttng_error_code ret_code
= LTTNG_OK
;
2268 DBG("Closing event notifier group notification file descriptor: fd = %d",
2269 event_notifier_group_notification_fd
);
2270 if (event_notifier_group_notification_fd
>= 0) {
2271 const int ret
= close(event_notifier_group_notification_fd
);
2273 PERROR("Failed to close event notifier group notification file descriptor: fd = %d",
2274 event_notifier_group_notification_fd
);
2282 unsigned long hash_trigger(const struct lttng_trigger
*trigger
)
2284 const struct lttng_condition
*condition
=
2285 lttng_trigger_get_const_condition(trigger
);
2287 return lttng_condition_hash(condition
);
2291 int match_trigger(struct cds_lfht_node
*node
, const void *key
)
2293 const struct ltt_kernel_event_notifier_rule
*event_notifier_rule
;
2294 const struct lttng_trigger
*trigger
= key
;
2296 event_notifier_rule
= caa_container_of(node
,
2297 const struct ltt_kernel_event_notifier_rule
, ht_node
);
2299 return lttng_trigger_is_equal(trigger
, event_notifier_rule
->trigger
);
2302 static enum lttng_error_code
kernel_create_event_notifier_rule(
2303 struct lttng_trigger
*trigger
,
2304 const struct lttng_credentials
*creds
, uint64_t token
)
2306 int err
, fd
, ret
= 0;
2307 enum lttng_error_code error_code_ret
;
2308 enum lttng_condition_status condition_status
;
2309 enum lttng_condition_type condition_type
;
2310 enum lttng_event_rule_type event_rule_type
;
2311 struct ltt_kernel_event_notifier_rule
*event_notifier_rule
;
2312 struct lttng_kernel_event_notifier kernel_event_notifier
= {};
2313 unsigned int capture_bytecode_count
= 0, i
;
2314 const struct lttng_condition
*condition
= NULL
;
2315 const struct lttng_event_rule
*event_rule
= NULL
;
2316 enum lttng_condition_status cond_status
;
2320 condition
= lttng_trigger_get_const_condition(trigger
);
2323 condition_type
= lttng_condition_get_type(condition
);
2324 assert(condition_type
== LTTNG_CONDITION_TYPE_ON_EVENT
);
2326 /* Does not acquire a reference. */
2327 condition_status
= lttng_condition_on_event_get_rule(
2328 condition
, &event_rule
);
2329 assert(condition_status
== LTTNG_CONDITION_STATUS_OK
);
2332 event_rule_type
= lttng_event_rule_get_type(event_rule
);
2333 assert(event_rule_type
!= LTTNG_EVENT_RULE_TYPE_UNKNOWN
);
2335 error_code_ret
= trace_kernel_create_event_notifier_rule(trigger
, token
,
2336 lttng_condition_on_event_get_error_counter_index(condition
),
2337 &event_notifier_rule
);
2338 if (error_code_ret
!= LTTNG_OK
) {
2342 error_code_ret
= trace_kernel_init_event_notifier_from_event_rule(
2343 event_rule
, &kernel_event_notifier
);
2344 if (error_code_ret
!= LTTNG_OK
) {
2348 kernel_event_notifier
.event
.token
= event_notifier_rule
->token
;
2349 kernel_event_notifier
.error_counter_idx
=
2350 lttng_condition_on_event_get_error_counter_index(condition
);
2352 fd
= kernctl_create_event_notifier(
2353 kernel_tracer_event_notifier_group_fd
,
2354 &kernel_event_notifier
);
2358 error_code_ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
2361 WARN("Failed to create kernel event notifier: not notifier type not implemented");
2362 error_code_ret
= LTTNG_ERR_KERN_EVENT_ENOSYS
;
2365 WARN("Failed to create kernel event notifier: not found: name = '%s'",
2366 kernel_event_notifier
.event
.name
);
2367 error_code_ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
2370 PERROR("Failed to create kernel event notifier: error code = %d, name = '%s'",
2371 fd
, kernel_event_notifier
.event
.name
);
2372 error_code_ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
2377 event_notifier_rule
->fd
= fd
;
2378 /* Prevent fd duplication after execlp(). */
2379 err
= fcntl(event_notifier_rule
->fd
, F_SETFD
, FD_CLOEXEC
);
2381 PERROR("Failed to set FD_CLOEXEC on kernel event notifier file descriptor: fd = %d",
2383 error_code_ret
= LTTNG_ERR_FATAL
;
2384 goto set_cloexec_error
;
2387 if (event_notifier_rule
->filter
) {
2388 err
= kernctl_filter(event_notifier_rule
->fd
, event_notifier_rule
->filter
);
2392 error_code_ret
= LTTNG_ERR_FILTER_NOMEM
;
2395 error_code_ret
= LTTNG_ERR_FILTER_INVAL
;
2402 if (lttng_event_rule_get_type(event_rule
) ==
2403 LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE
) {
2404 ret
= userspace_probe_event_rule_add_callsites(
2405 event_rule
, creds
, event_notifier_rule
->fd
);
2407 error_code_ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
2408 goto add_callsite_error
;
2412 /* Set the capture bytecode if any. */
2413 cond_status
= lttng_condition_on_event_get_capture_descriptor_count(
2414 condition
, &capture_bytecode_count
);
2415 assert(cond_status
== LTTNG_CONDITION_STATUS_OK
);
2417 for (i
= 0; i
< capture_bytecode_count
; i
++) {
2418 const struct lttng_bytecode
*capture_bytecode
=
2419 lttng_condition_on_event_get_capture_bytecode_at_index(
2422 if (capture_bytecode
== NULL
) {
2423 ERR("Unexpected NULL capture bytecode on condition");
2424 error_code_ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
2428 ret
= kernctl_capture(event_notifier_rule
->fd
, capture_bytecode
);
2430 ERR("Failed to set capture bytecode on event notifier rule fd: fd = %d",
2431 event_notifier_rule
->fd
);
2432 error_code_ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
2437 err
= kernctl_enable(event_notifier_rule
->fd
);
2441 error_code_ret
= LTTNG_ERR_KERN_EVENT_EXIST
;
2444 PERROR("enable kernel event notifier");
2445 error_code_ret
= LTTNG_ERR_KERN_ENABLE_FAIL
;
2451 /* Add trigger to kernel token mapping in the hash table. */
2453 cds_lfht_add(kernel_token_to_event_notifier_rule_ht
, hash_trigger(trigger
),
2454 &event_notifier_rule
->ht_node
);
2457 DBG("Created kernel event notifier: name = '%s', fd = %d",
2458 kernel_event_notifier
.event
.name
,
2459 event_notifier_rule
->fd
);
2469 const int close_ret
= close(event_notifier_rule
->fd
);
2472 PERROR("Failed to close kernel event notifier file descriptor: fd = %d",
2473 event_notifier_rule
->fd
);
2477 free(event_notifier_rule
);
2479 return error_code_ret
;
2482 enum lttng_error_code
kernel_register_event_notifier(
2483 struct lttng_trigger
*trigger
,
2484 const struct lttng_credentials
*cmd_creds
)
2486 enum lttng_error_code ret
;
2487 enum lttng_condition_status status
;
2488 enum lttng_domain_type domain_type
;
2489 const struct lttng_event_rule
*event_rule
;
2490 const struct lttng_condition
*const condition
=
2491 lttng_trigger_get_const_condition(trigger
);
2492 const uint64_t token
= lttng_trigger_get_tracer_token(trigger
);
2496 /* Does not acquire a reference to the event rule. */
2497 status
= lttng_condition_on_event_get_rule(
2498 condition
, &event_rule
);
2499 assert(status
== LTTNG_CONDITION_STATUS_OK
);
2501 domain_type
= lttng_event_rule_get_domain_type(event_rule
);
2502 assert(domain_type
== LTTNG_DOMAIN_KERNEL
);
2504 ret
= kernel_create_event_notifier_rule(trigger
, cmd_creds
, token
);
2505 if (ret
!= LTTNG_OK
) {
2506 ERR("Failed to create kernel event notifier rule");
2512 enum lttng_error_code
kernel_unregister_event_notifier(
2513 const struct lttng_trigger
*trigger
)
2515 struct ltt_kernel_event_notifier_rule
*token_event_rule_element
;
2516 struct cds_lfht_node
*node
;
2517 struct cds_lfht_iter iter
;
2518 enum lttng_error_code error_code_ret
;
2523 cds_lfht_lookup(kernel_token_to_event_notifier_rule_ht
,
2524 hash_trigger(trigger
), match_trigger
, trigger
, &iter
);
2526 node
= cds_lfht_iter_get_node(&iter
);
2528 error_code_ret
= LTTNG_ERR_TRIGGER_NOT_FOUND
;
2532 token_event_rule_element
= caa_container_of(node
,
2533 struct ltt_kernel_event_notifier_rule
, ht_node
);
2535 ret
= kernel_disable_event_notifier_rule(token_event_rule_element
);
2537 error_code_ret
= LTTNG_ERR_FATAL
;
2541 trace_kernel_destroy_event_notifier_rule(token_event_rule_element
);
2542 error_code_ret
= LTTNG_OK
;
2547 return error_code_ret
;
2550 int kernel_get_notification_fd(void)
2552 return kernel_tracer_event_notifier_group_notification_fd
;