4 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
5 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; only
10 * version 2.1 of the License.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include <sys/types.h>
24 #include <sys/socket.h>
25 #include <sys/prctl.h>
28 #include <sys/types.h>
34 #include <semaphore.h>
38 #include <urcu/uatomic.h>
39 #include <urcu/futex.h>
40 #include <urcu/compiler.h>
42 #include <lttng/ust-events.h>
43 #include <lttng/ust-abi.h>
44 #include <lttng/ust.h>
46 #include <usterr-signal-safe.h>
47 #include "tracepoint-internal.h"
48 #include "ltt-tracer-core.h"
49 #include "../libringbuffer/tlsfixup.h"
52 * Has lttng ust comm constructor been called ?
54 static int initialized
;
57 * The ust_lock/ust_unlock lock is used as a communication thread mutex.
58 * Held when handling a command, also held by fork() to deal with
59 * removal of threads, and by exit path.
62 /* Should the ust comm thread quit ? */
63 static int lttng_ust_comm_should_quit
;
66 * Wait for either of these before continuing to the main
68 * - the register_done message from sessiond daemon
69 * (will let the sessiond daemon enable sessions before main
71 * - sessiond daemon is not reachable.
72 * - timeout (ensuring applications are resilient to session
75 static sem_t constructor_wait
;
77 * Doing this for both the global and local sessiond.
79 static int sem_count
= { 2 };
82 * Info about socket and associated listener thread.
86 pthread_t ust_listener
; /* listener thread */
88 int constructor_sem_posted
;
92 char sock_path
[PATH_MAX
];
95 char wait_shm_path
[PATH_MAX
];
99 /* Socket from app (connect) to session daemon (listen) for communication */
100 struct sock_info global_apps
= {
107 .sock_path
= DEFAULT_GLOBAL_APPS_UNIX_SOCK
,
110 .wait_shm_path
= DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH
,
113 /* TODO: allow global_apps_sock_path override */
115 struct sock_info local_apps
= {
119 .allowed
= 0, /* Check setuid bit first */
124 static int wait_poll_fallback
;
126 extern void ltt_ring_buffer_client_overwrite_init(void);
127 extern void ltt_ring_buffer_client_discard_init(void);
128 extern void ltt_ring_buffer_metadata_client_init(void);
129 extern void ltt_ring_buffer_client_overwrite_exit(void);
130 extern void ltt_ring_buffer_client_discard_exit(void);
131 extern void ltt_ring_buffer_metadata_client_exit(void);
134 int setup_local_apps(void)
136 const char *home_dir
;
141 * Disallow per-user tracing for setuid binaries.
143 if (uid
!= geteuid()) {
144 local_apps
.allowed
= 0;
147 local_apps
.allowed
= 1;
149 home_dir
= (const char *) getenv("HOME");
152 snprintf(local_apps
.sock_path
, PATH_MAX
,
153 DEFAULT_HOME_APPS_UNIX_SOCK
, home_dir
);
154 snprintf(local_apps
.wait_shm_path
, PATH_MAX
,
155 DEFAULT_HOME_APPS_WAIT_SHM_PATH
, uid
);
160 int register_app_to_sessiond(int socket
)
171 uint32_t bits_per_long
;
172 char name
[16]; /* process name */
175 reg_msg
.major
= LTTNG_UST_COMM_VERSION_MAJOR
;
176 reg_msg
.minor
= LTTNG_UST_COMM_VERSION_MINOR
;
177 reg_msg
.pid
= getpid();
178 reg_msg
.ppid
= getppid();
179 reg_msg
.uid
= getuid();
180 reg_msg
.gid
= getgid();
181 reg_msg
.bits_per_long
= CAA_BITS_PER_LONG
;
182 prctl_ret
= prctl(PR_GET_NAME
, (unsigned long) reg_msg
.name
, 0, 0, 0);
184 ERR("Error executing prctl");
188 ret
= ustcomm_send_unix_sock(socket
, ®_msg
, sizeof(reg_msg
));
189 if (ret
>= 0 && ret
!= sizeof(reg_msg
))
195 int send_reply(int sock
, struct ustcomm_ust_reply
*lur
)
199 len
= ustcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
202 DBG("message successfully sent");
205 if (errno
== ECONNRESET
) {
206 printf("remote end closed connection\n");
211 printf("incorrect message size: %zd\n", len
);
217 int handle_register_done(struct sock_info
*sock_info
)
221 if (sock_info
->constructor_sem_posted
)
223 sock_info
->constructor_sem_posted
= 1;
224 if (uatomic_read(&sem_count
) <= 0) {
227 ret
= uatomic_add_return(&sem_count
, -1);
229 ret
= sem_post(&constructor_wait
);
236 int handle_message(struct sock_info
*sock_info
,
237 int sock
, struct ustcomm_ust_msg
*lum
)
240 const struct lttng_ust_objd_ops
*ops
;
241 struct ustcomm_ust_reply lur
;
247 memset(&lur
, 0, sizeof(lur
));
249 if (lttng_ust_comm_should_quit
) {
254 ops
= objd_ops(lum
->handle
);
261 case LTTNG_UST_REGISTER_DONE
:
262 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
263 ret
= handle_register_done(sock_info
);
267 case LTTNG_UST_RELEASE
:
268 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
271 ret
= lttng_ust_objd_unref(lum
->handle
);
275 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
276 (unsigned long) &lum
->u
,
284 lur
.handle
= lum
->handle
;
288 lur
.ret_code
= USTCOMM_OK
;
290 //lur.ret_code = USTCOMM_SESSION_FAIL;
295 case LTTNG_UST_STREAM
:
297 * Special-case reply to send stream info.
300 lur
.u
.stream
.memory_map_size
= *args
.stream
.memory_map_size
;
301 shm_fd
= *args
.stream
.shm_fd
;
302 wait_fd
= *args
.stream
.wait_fd
;
304 case LTTNG_UST_METADATA
:
305 case LTTNG_UST_CHANNEL
:
306 lur
.u
.channel
.memory_map_size
= *args
.channel
.memory_map_size
;
307 shm_fd
= *args
.channel
.shm_fd
;
308 wait_fd
= *args
.channel
.wait_fd
;
310 case LTTNG_UST_TRACER_VERSION
:
311 lur
.u
.version
= lum
->u
.version
;
313 case LTTNG_UST_TRACEPOINT_LIST_GET
:
314 memcpy(&lur
.u
.tracepoint
, &lum
->u
.tracepoint
, sizeof(lur
.u
.tracepoint
));
318 ret
= send_reply(sock
, &lur
);
320 perror("error sending reply");
324 if ((lum
->cmd
== LTTNG_UST_STREAM
325 || lum
->cmd
== LTTNG_UST_CHANNEL
326 || lum
->cmd
== LTTNG_UST_METADATA
)
327 && lur
.ret_code
== USTCOMM_OK
) {
330 /* we also need to send the file descriptors. */
331 ret
= ustcomm_send_fds_unix_sock(sock
,
335 perror("send shm_fd");
339 * The sessiond expects 2 file descriptors, even upon
342 ret
= ustcomm_send_fds_unix_sock(sock
,
346 perror("send wait_fd");
355 * We still have the memory map reference, and the fds have been
356 * sent to the sessiond. We can therefore close those fds. Note
357 * that we keep the write side of the wait_fd open, but close
360 if (lur
.ret_code
== USTCOMM_OK
) {
362 case LTTNG_UST_STREAM
:
366 PERROR("Error closing stream shm_fd");
368 *args
.stream
.shm_fd
= -1;
371 ret
= close(wait_fd
);
373 PERROR("Error closing stream wait_fd");
375 *args
.stream
.wait_fd
= -1;
378 case LTTNG_UST_METADATA
:
379 case LTTNG_UST_CHANNEL
:
383 PERROR("Error closing channel shm_fd");
385 *args
.channel
.shm_fd
= -1;
388 ret
= close(wait_fd
);
390 PERROR("Error closing channel wait_fd");
392 *args
.channel
.wait_fd
= -1;
404 void cleanup_sock_info(struct sock_info
*sock_info
, int exiting
)
408 if (sock_info
->socket
!= -1) {
409 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
411 ERR("Error closing apps socket");
413 sock_info
->socket
= -1;
415 if (sock_info
->root_handle
!= -1) {
416 ret
= lttng_ust_objd_unref(sock_info
->root_handle
);
418 ERR("Error unref root handle");
420 sock_info
->root_handle
= -1;
422 sock_info
->constructor_sem_posted
= 0;
424 * wait_shm_mmap is used by listener threads outside of the
425 * ust lock, so we cannot tear it down ourselves, because we
426 * cannot join on these threads. Leave this task to the OS
429 if (!exiting
&& sock_info
->wait_shm_mmap
) {
430 ret
= munmap(sock_info
->wait_shm_mmap
, sysconf(_SC_PAGE_SIZE
));
432 ERR("Error unmapping wait shm");
434 sock_info
->wait_shm_mmap
= NULL
;
439 * Using fork to set umask in the child process (not multi-thread safe).
440 * We deal with the shm_open vs ftruncate race (happening when the
441 * sessiond owns the shm and does not let everybody modify it, to ensure
442 * safety against shm_unlink) by simply letting the mmap fail and
443 * retrying after a few seconds.
444 * For global shm, everybody has rw access to it until the sessiond
448 int get_wait_shm(struct sock_info
*sock_info
, size_t mmap_size
)
450 int wait_shm_fd
, ret
;
454 * Try to open read-only.
456 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
457 if (wait_shm_fd
>= 0) {
459 } else if (wait_shm_fd
< 0 && errno
!= ENOENT
) {
461 * Real-only open did not work, and it's not because the
462 * entry was not present. It's a failure that prohibits
465 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
469 * If the open failed because the file did not exist, try
470 * creating it ourself.
477 * Parent: wait for child to return, in which case the
478 * shared memory map will have been created.
481 if (pid
< 0 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0) {
486 * Try to open read-only again after creation.
488 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
489 if (wait_shm_fd
< 0) {
491 * Real-only open did not work. It's a failure
492 * that prohibits using shm.
494 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
498 } else if (pid
== 0) {
502 create_mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
;
503 if (sock_info
->global
)
504 create_mode
|= S_IROTH
| S_IWGRP
| S_IWOTH
;
506 * We're alone in a child process, so we can modify the
507 * process-wide umask.
511 * Try creating shm (or get rw access).
512 * We don't do an exclusive open, because we allow other
513 * processes to create+ftruncate it concurrently.
515 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
,
516 O_RDWR
| O_CREAT
, create_mode
);
517 if (wait_shm_fd
>= 0) {
518 ret
= ftruncate(wait_shm_fd
, mmap_size
);
526 * For local shm, we need to have rw access to accept
527 * opening it: this means the local sessiond will be
528 * able to wake us up. For global shm, we open it even
529 * if rw access is not granted, because the root.root
530 * sessiond will be able to override all rights and wake
533 if (!sock_info
->global
&& errno
!= EACCES
) {
534 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
538 * The shm exists, but we cannot open it RW. Report
546 if (wait_shm_fd
>= 0 && !sock_info
->global
) {
550 * Ensure that our user is the owner of the shm file for
551 * local shm. If we do not own the file, it means our
552 * sessiond will not have access to wake us up (there is
553 * probably a rogue process trying to fake our
554 * sessiond). Fallback to polling method in this case.
556 ret
= fstat(wait_shm_fd
, &statbuf
);
561 if (statbuf
.st_uid
!= getuid())
567 ret
= close(wait_shm_fd
);
569 PERROR("Error closing fd");
575 char *get_map_shm(struct sock_info
*sock_info
)
577 size_t mmap_size
= sysconf(_SC_PAGE_SIZE
);
578 int wait_shm_fd
, ret
;
581 wait_shm_fd
= get_wait_shm(sock_info
, mmap_size
);
582 if (wait_shm_fd
< 0) {
585 wait_shm_mmap
= mmap(NULL
, mmap_size
, PROT_READ
,
586 MAP_SHARED
, wait_shm_fd
, 0);
587 /* close shm fd immediately after taking the mmap reference */
588 ret
= close(wait_shm_fd
);
590 PERROR("Error closing fd");
592 if (wait_shm_mmap
== MAP_FAILED
) {
593 DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
596 return wait_shm_mmap
;
603 void wait_for_sessiond(struct sock_info
*sock_info
)
608 if (lttng_ust_comm_should_quit
) {
611 if (wait_poll_fallback
) {
614 if (!sock_info
->wait_shm_mmap
) {
615 sock_info
->wait_shm_mmap
= get_map_shm(sock_info
);
616 if (!sock_info
->wait_shm_mmap
)
621 DBG("Waiting for %s apps sessiond", sock_info
->name
);
622 /* Wait for futex wakeup */
623 if (uatomic_read((int32_t *) sock_info
->wait_shm_mmap
) == 0) {
624 ret
= futex_async((int32_t *) sock_info
->wait_shm_mmap
,
625 FUTEX_WAIT
, 0, NULL
, NULL
, 0);
627 if (errno
== EFAULT
) {
628 wait_poll_fallback
= 1;
630 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
631 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
632 "Please upgrade your kernel "
633 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
634 "mainline). LTTng-UST will use polling mode fallback.");
652 * This thread does not allocate any resource, except within
653 * handle_message, within mutex protection. This mutex protects against
655 * The other moment it allocates resources is at socket connexion, which
656 * is also protected by the mutex.
659 void *ust_listener_thread(void *arg
)
661 struct sock_info
*sock_info
= arg
;
662 int sock
, ret
, prev_connect_failed
= 0, has_waited
= 0;
664 /* Restart trying to connect to the session daemon */
666 if (prev_connect_failed
) {
667 /* Wait for sessiond availability with pipe */
668 wait_for_sessiond(sock_info
);
672 * Sleep for 5 seconds before retrying after a
673 * sequence of failure / wait / failure. This
674 * deals with a killed or broken session daemon.
679 prev_connect_failed
= 0;
683 if (lttng_ust_comm_should_quit
) {
688 if (sock_info
->socket
!= -1) {
689 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
691 ERR("Error closing %s apps socket", sock_info
->name
);
693 sock_info
->socket
= -1;
697 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
);
699 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
700 prev_connect_failed
= 1;
702 * If we cannot find the sessiond daemon, don't delay
703 * constructor execution.
705 ret
= handle_register_done(sock_info
);
711 sock_info
->socket
= sock
= ret
;
714 * Create only one root handle per listener thread for the whole
717 if (sock_info
->root_handle
== -1) {
718 ret
= lttng_abi_create_root_handle();
720 ERR("Error creating root handle");
724 sock_info
->root_handle
= ret
;
727 ret
= register_app_to_sessiond(sock
);
729 ERR("Error registering to %s apps socket", sock_info
->name
);
730 prev_connect_failed
= 1;
732 * If we cannot register to the sessiond daemon, don't
733 * delay constructor execution.
735 ret
= handle_register_done(sock_info
);
744 struct ustcomm_ust_msg lum
;
746 len
= ustcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
748 case 0: /* orderly shutdown */
749 DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info
->name
);
752 * Either sessiond has shutdown or refused us by closing the socket.
753 * In either case, we don't want to delay construction execution,
754 * and we need to wait before retry.
756 prev_connect_failed
= 1;
758 * If we cannot register to the sessiond daemon, don't
759 * delay constructor execution.
761 ret
= handle_register_done(sock_info
);
766 DBG("message received\n");
767 ret
= handle_message(sock_info
, sock
, &lum
);
769 ERR("Error handling message for %s socket", sock_info
->name
);
773 DBG("Receive failed from lttng-sessiond with errno %d", errno
);
774 if (errno
== ECONNRESET
) {
775 ERR("%s remote end closed connection\n", sock_info
->name
);
780 ERR("incorrect message size (%s socket): %zd\n", sock_info
->name
, len
);
786 goto restart
; /* try to reconnect */
792 * Return values: -1: don't wait. 0: wait forever. 1: timeout wait.
795 int get_timeout(struct timespec
*constructor_timeout
)
797 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
801 str_delay
= getenv("LTTNG_UST_REGISTER_TIMEOUT");
803 constructor_delay_ms
= strtol(str_delay
, NULL
, 10);
806 switch (constructor_delay_ms
) {
807 case -1:/* fall-through */
809 return constructor_delay_ms
;
815 * If we are unable to find the current time, don't wait.
817 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
821 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
822 constructor_timeout
->tv_nsec
+=
823 (constructor_delay_ms
% 1000UL) * 1000000UL;
824 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
825 constructor_timeout
->tv_sec
++;
826 constructor_timeout
->tv_nsec
-= 1000000000UL;
832 * sessiond monitoring thread: monitor presence of global and per-user
833 * sessiond by polling the application common named pipe.
837 void __attribute__((constructor
)) lttng_ust_init(void)
839 struct timespec constructor_timeout
;
840 sigset_t sig_all_blocked
, orig_parent_mask
;
844 if (uatomic_xchg(&initialized
, 1) == 1)
848 * Fixup interdependency between TLS fixup mutex (which happens
849 * to be the dynamic linker mutex) and ust_lock, taken within
852 lttng_fixup_event_tls();
853 lttng_fixup_ringbuffer_tls();
854 lttng_fixup_vtid_tls();
857 * We want precise control over the order in which we construct
858 * our sub-libraries vs starting to receive commands from
859 * sessiond (otherwise leading to errors when trying to create
860 * sessiond before the init functions are completed).
864 ltt_ring_buffer_metadata_client_init();
865 ltt_ring_buffer_client_overwrite_init();
866 ltt_ring_buffer_client_discard_init();
868 timeout_mode
= get_timeout(&constructor_timeout
);
870 ret
= sem_init(&constructor_wait
, 0, 0);
873 ret
= setup_local_apps();
875 ERR("Error setting up to local apps");
878 /* A new thread created by pthread_create inherits the signal mask
879 * from the parent. To avoid any signal being received by the
880 * listener thread, we block all signals temporarily in the parent,
881 * while we create the listener thread.
883 sigfillset(&sig_all_blocked
);
884 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_parent_mask
);
886 ERR("pthread_sigmask: %s", strerror(ret
));
889 ret
= pthread_create(&global_apps
.ust_listener
, NULL
,
890 ust_listener_thread
, &global_apps
);
892 ERR("pthread_create global: %s", strerror(ret
));
894 if (local_apps
.allowed
) {
895 ret
= pthread_create(&local_apps
.ust_listener
, NULL
,
896 ust_listener_thread
, &local_apps
);
898 ERR("pthread_create local: %s", strerror(ret
));
901 handle_register_done(&local_apps
);
904 /* Restore original signal mask in parent */
905 ret
= pthread_sigmask(SIG_SETMASK
, &orig_parent_mask
, NULL
);
907 ERR("pthread_sigmask: %s", strerror(ret
));
910 switch (timeout_mode
) {
911 case 1: /* timeout wait */
913 ret
= sem_timedwait(&constructor_wait
,
914 &constructor_timeout
);
915 } while (ret
< 0 && errno
== EINTR
);
916 if (ret
< 0 && errno
== ETIMEDOUT
) {
917 ERR("Timed out waiting for ltt-sessiond");
922 case -1:/* wait forever */
924 ret
= sem_wait(&constructor_wait
);
925 } while (ret
< 0 && errno
== EINTR
);
928 case 0: /* no timeout */
934 void lttng_ust_cleanup(int exiting
)
936 cleanup_sock_info(&global_apps
, exiting
);
937 if (local_apps
.allowed
) {
938 cleanup_sock_info(&local_apps
, exiting
);
941 * The teardown in this function all affect data structures
942 * accessed under the UST lock by the listener thread. This
943 * lock, along with the lttng_ust_comm_should_quit flag, ensure
944 * that none of these threads are accessing this data at this
947 lttng_ust_abi_exit();
948 lttng_ust_events_exit();
949 ltt_ring_buffer_client_discard_exit();
950 ltt_ring_buffer_client_overwrite_exit();
951 ltt_ring_buffer_metadata_client_exit();
954 /* Reinitialize values for fork */
956 lttng_ust_comm_should_quit
= 0;
961 void __attribute__((destructor
)) lttng_ust_exit(void)
966 * Using pthread_cancel here because:
967 * A) we don't want to hang application teardown.
968 * B) the thread is not allocating any resource.
972 * Require the communication thread to quit. Synchronize with
973 * mutexes to ensure it is not in a mutex critical section when
974 * pthread_cancel is later called.
977 lttng_ust_comm_should_quit
= 1;
981 ret
= pthread_cancel(global_apps
.ust_listener
);
983 ERR("Error cancelling global ust listener thread: %s",
986 if (local_apps
.allowed
) {
987 ret
= pthread_cancel(local_apps
.ust_listener
);
989 ERR("Error cancelling local ust listener thread: %s",
994 * Do NOT join threads: use of sys_futex makes it impossible to
995 * join the threads without using async-cancel, but async-cancel
996 * is delivered by a signal, which could hit the target thread
997 * anywhere in its code path, including while the ust_lock() is
998 * held, causing a deadlock for the other thread. Let the OS
999 * cleanup the threads if there are stalled in a syscall.
1001 lttng_ust_cleanup(1);
1005 * We exclude the worker threads across fork and clone (except
1006 * CLONE_VM), because these system calls only keep the forking thread
1007 * running in the child. Therefore, we don't want to call fork or clone
1008 * in the middle of an tracepoint or ust tracing state modification.
1009 * Holding this mutex protects these structures across fork and clone.
1011 void ust_before_fork(sigset_t
*save_sigset
)
1014 * Disable signals. This is to avoid that the child intervenes
1015 * before it is properly setup for tracing. It is safer to
1016 * disable all signals, because then we know we are not breaking
1017 * anything by restoring the original mask.
1022 /* Disable signals */
1023 sigfillset(&all_sigs
);
1024 ret
= sigprocmask(SIG_BLOCK
, &all_sigs
, save_sigset
);
1026 PERROR("sigprocmask");
1029 rcu_bp_before_fork();
1032 static void ust_after_fork_common(sigset_t
*restore_sigset
)
1036 DBG("process %d", getpid());
1038 /* Restore signals */
1039 ret
= sigprocmask(SIG_SETMASK
, restore_sigset
, NULL
);
1041 PERROR("sigprocmask");
1045 void ust_after_fork_parent(sigset_t
*restore_sigset
)
1047 DBG("process %d", getpid());
1048 rcu_bp_after_fork_parent();
1049 /* Release mutexes and reenable signals */
1050 ust_after_fork_common(restore_sigset
);
1054 * After fork, in the child, we need to cleanup all the leftover state,
1055 * except the worker thread which already magically disappeared thanks
1056 * to the weird Linux fork semantics. After tyding up, we call
1057 * lttng_ust_init() again to start over as a new PID.
1059 * This is meant for forks() that have tracing in the child between the
1060 * fork and following exec call (if there is any).
1062 void ust_after_fork_child(sigset_t
*restore_sigset
)
1064 DBG("process %d", getpid());
1065 /* Release urcu mutexes */
1066 rcu_bp_after_fork_child();
1067 lttng_ust_cleanup(0);
1068 lttng_context_vtid_reset();
1069 /* Release mutexes and reenable signals */
1070 ust_after_fork_common(restore_sigset
);