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 * Counting nesting within lttng-ust. Used to ensure that calling fork()
83 * from liblttng-ust does not execute the pre/post fork handlers.
85 static int __thread lttng_ust_nest_count
;
88 * Info about socket and associated listener thread.
92 pthread_t ust_listener
; /* listener thread */
94 int constructor_sem_posted
;
98 char sock_path
[PATH_MAX
];
101 char wait_shm_path
[PATH_MAX
];
105 /* Socket from app (connect) to session daemon (listen) for communication */
106 struct sock_info global_apps
= {
113 .sock_path
= DEFAULT_GLOBAL_APPS_UNIX_SOCK
,
116 .wait_shm_path
= DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH
,
119 /* TODO: allow global_apps_sock_path override */
121 struct sock_info local_apps
= {
125 .allowed
= 0, /* Check setuid bit first */
130 static int wait_poll_fallback
;
132 extern void ltt_ring_buffer_client_overwrite_init(void);
133 extern void ltt_ring_buffer_client_discard_init(void);
134 extern void ltt_ring_buffer_metadata_client_init(void);
135 extern void ltt_ring_buffer_client_overwrite_exit(void);
136 extern void ltt_ring_buffer_client_discard_exit(void);
137 extern void ltt_ring_buffer_metadata_client_exit(void);
140 int setup_local_apps(void)
142 const char *home_dir
;
147 * Disallow per-user tracing for setuid binaries.
149 if (uid
!= geteuid()) {
150 local_apps
.allowed
= 0;
153 local_apps
.allowed
= 1;
155 home_dir
= (const char *) getenv("HOME");
158 snprintf(local_apps
.sock_path
, PATH_MAX
,
159 DEFAULT_HOME_APPS_UNIX_SOCK
, home_dir
);
160 snprintf(local_apps
.wait_shm_path
, PATH_MAX
,
161 DEFAULT_HOME_APPS_WAIT_SHM_PATH
, uid
);
166 int register_app_to_sessiond(int socket
)
177 uint32_t bits_per_long
;
178 char name
[16]; /* process name */
181 reg_msg
.major
= LTTNG_UST_COMM_VERSION_MAJOR
;
182 reg_msg
.minor
= LTTNG_UST_COMM_VERSION_MINOR
;
183 reg_msg
.pid
= getpid();
184 reg_msg
.ppid
= getppid();
185 reg_msg
.uid
= getuid();
186 reg_msg
.gid
= getgid();
187 reg_msg
.bits_per_long
= CAA_BITS_PER_LONG
;
188 prctl_ret
= prctl(PR_GET_NAME
, (unsigned long) reg_msg
.name
, 0, 0, 0);
190 ERR("Error executing prctl");
194 ret
= ustcomm_send_unix_sock(socket
, ®_msg
, sizeof(reg_msg
));
195 if (ret
>= 0 && ret
!= sizeof(reg_msg
))
201 int send_reply(int sock
, struct ustcomm_ust_reply
*lur
)
205 len
= ustcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
208 DBG("message successfully sent");
211 if (errno
== ECONNRESET
) {
212 printf("remote end closed connection\n");
217 printf("incorrect message size: %zd\n", len
);
223 int handle_register_done(struct sock_info
*sock_info
)
227 if (sock_info
->constructor_sem_posted
)
229 sock_info
->constructor_sem_posted
= 1;
230 if (uatomic_read(&sem_count
) <= 0) {
233 ret
= uatomic_add_return(&sem_count
, -1);
235 ret
= sem_post(&constructor_wait
);
242 int handle_message(struct sock_info
*sock_info
,
243 int sock
, struct ustcomm_ust_msg
*lum
)
246 const struct lttng_ust_objd_ops
*ops
;
247 struct ustcomm_ust_reply lur
;
253 memset(&lur
, 0, sizeof(lur
));
255 if (lttng_ust_comm_should_quit
) {
260 ops
= objd_ops(lum
->handle
);
267 case LTTNG_UST_REGISTER_DONE
:
268 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
269 ret
= handle_register_done(sock_info
);
273 case LTTNG_UST_RELEASE
:
274 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
277 ret
= lttng_ust_objd_unref(lum
->handle
);
281 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
282 (unsigned long) &lum
->u
,
290 lur
.handle
= lum
->handle
;
294 lur
.ret_code
= USTCOMM_OK
;
296 //lur.ret_code = USTCOMM_SESSION_FAIL;
301 case LTTNG_UST_STREAM
:
303 * Special-case reply to send stream info.
306 lur
.u
.stream
.memory_map_size
= *args
.stream
.memory_map_size
;
307 shm_fd
= *args
.stream
.shm_fd
;
308 wait_fd
= *args
.stream
.wait_fd
;
310 case LTTNG_UST_METADATA
:
311 case LTTNG_UST_CHANNEL
:
312 lur
.u
.channel
.memory_map_size
= *args
.channel
.memory_map_size
;
313 shm_fd
= *args
.channel
.shm_fd
;
314 wait_fd
= *args
.channel
.wait_fd
;
316 case LTTNG_UST_TRACER_VERSION
:
317 lur
.u
.version
= lum
->u
.version
;
319 case LTTNG_UST_TRACEPOINT_LIST_GET
:
320 memcpy(&lur
.u
.tracepoint
, &lum
->u
.tracepoint
, sizeof(lur
.u
.tracepoint
));
324 ret
= send_reply(sock
, &lur
);
326 perror("error sending reply");
330 if ((lum
->cmd
== LTTNG_UST_STREAM
331 || lum
->cmd
== LTTNG_UST_CHANNEL
332 || lum
->cmd
== LTTNG_UST_METADATA
)
333 && lur
.ret_code
== USTCOMM_OK
) {
336 /* we also need to send the file descriptors. */
337 ret
= ustcomm_send_fds_unix_sock(sock
,
341 perror("send shm_fd");
345 * The sessiond expects 2 file descriptors, even upon
348 ret
= ustcomm_send_fds_unix_sock(sock
,
352 perror("send wait_fd");
361 * We still have the memory map reference, and the fds have been
362 * sent to the sessiond. We can therefore close those fds. Note
363 * that we keep the write side of the wait_fd open, but close
366 if (lur
.ret_code
== USTCOMM_OK
) {
368 case LTTNG_UST_STREAM
:
372 PERROR("Error closing stream shm_fd");
374 *args
.stream
.shm_fd
= -1;
377 ret
= close(wait_fd
);
379 PERROR("Error closing stream wait_fd");
381 *args
.stream
.wait_fd
= -1;
384 case LTTNG_UST_METADATA
:
385 case LTTNG_UST_CHANNEL
:
389 PERROR("Error closing channel shm_fd");
391 *args
.channel
.shm_fd
= -1;
394 ret
= close(wait_fd
);
396 PERROR("Error closing channel wait_fd");
398 *args
.channel
.wait_fd
= -1;
410 void cleanup_sock_info(struct sock_info
*sock_info
, int exiting
)
414 if (sock_info
->socket
!= -1) {
415 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
417 ERR("Error closing apps socket");
419 sock_info
->socket
= -1;
421 if (sock_info
->root_handle
!= -1) {
422 ret
= lttng_ust_objd_unref(sock_info
->root_handle
);
424 ERR("Error unref root handle");
426 sock_info
->root_handle
= -1;
428 sock_info
->constructor_sem_posted
= 0;
430 * wait_shm_mmap is used by listener threads outside of the
431 * ust lock, so we cannot tear it down ourselves, because we
432 * cannot join on these threads. Leave this task to the OS
435 if (!exiting
&& sock_info
->wait_shm_mmap
) {
436 ret
= munmap(sock_info
->wait_shm_mmap
, sysconf(_SC_PAGE_SIZE
));
438 ERR("Error unmapping wait shm");
440 sock_info
->wait_shm_mmap
= NULL
;
445 * Using fork to set umask in the child process (not multi-thread safe).
446 * We deal with the shm_open vs ftruncate race (happening when the
447 * sessiond owns the shm and does not let everybody modify it, to ensure
448 * safety against shm_unlink) by simply letting the mmap fail and
449 * retrying after a few seconds.
450 * For global shm, everybody has rw access to it until the sessiond
454 int get_wait_shm(struct sock_info
*sock_info
, size_t mmap_size
)
456 int wait_shm_fd
, ret
;
460 * Try to open read-only.
462 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
463 if (wait_shm_fd
>= 0) {
465 } else if (wait_shm_fd
< 0 && errno
!= ENOENT
) {
467 * Real-only open did not work, and it's not because the
468 * entry was not present. It's a failure that prohibits
471 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
475 * If the open failed because the file did not exist, try
476 * creating it ourself.
478 lttng_ust_nest_count
++;
480 lttng_ust_nest_count
--;
485 * Parent: wait for child to return, in which case the
486 * shared memory map will have been created.
489 if (pid
< 0 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0) {
494 * Try to open read-only again after creation.
496 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
497 if (wait_shm_fd
< 0) {
499 * Real-only open did not work. It's a failure
500 * that prohibits using shm.
502 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
506 } else if (pid
== 0) {
510 create_mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
;
511 if (sock_info
->global
)
512 create_mode
|= S_IROTH
| S_IWGRP
| S_IWOTH
;
514 * We're alone in a child process, so we can modify the
515 * process-wide umask.
519 * Try creating shm (or get rw access).
520 * We don't do an exclusive open, because we allow other
521 * processes to create+ftruncate it concurrently.
523 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
,
524 O_RDWR
| O_CREAT
, create_mode
);
525 if (wait_shm_fd
>= 0) {
526 ret
= ftruncate(wait_shm_fd
, mmap_size
);
534 * For local shm, we need to have rw access to accept
535 * opening it: this means the local sessiond will be
536 * able to wake us up. For global shm, we open it even
537 * if rw access is not granted, because the root.root
538 * sessiond will be able to override all rights and wake
541 if (!sock_info
->global
&& errno
!= EACCES
) {
542 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
546 * The shm exists, but we cannot open it RW. Report
554 if (wait_shm_fd
>= 0 && !sock_info
->global
) {
558 * Ensure that our user is the owner of the shm file for
559 * local shm. If we do not own the file, it means our
560 * sessiond will not have access to wake us up (there is
561 * probably a rogue process trying to fake our
562 * sessiond). Fallback to polling method in this case.
564 ret
= fstat(wait_shm_fd
, &statbuf
);
569 if (statbuf
.st_uid
!= getuid())
575 ret
= close(wait_shm_fd
);
577 PERROR("Error closing fd");
583 char *get_map_shm(struct sock_info
*sock_info
)
585 size_t mmap_size
= sysconf(_SC_PAGE_SIZE
);
586 int wait_shm_fd
, ret
;
589 wait_shm_fd
= get_wait_shm(sock_info
, mmap_size
);
590 if (wait_shm_fd
< 0) {
593 wait_shm_mmap
= mmap(NULL
, mmap_size
, PROT_READ
,
594 MAP_SHARED
, wait_shm_fd
, 0);
595 /* close shm fd immediately after taking the mmap reference */
596 ret
= close(wait_shm_fd
);
598 PERROR("Error closing fd");
600 if (wait_shm_mmap
== MAP_FAILED
) {
601 DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
604 return wait_shm_mmap
;
611 void wait_for_sessiond(struct sock_info
*sock_info
)
616 if (lttng_ust_comm_should_quit
) {
619 if (wait_poll_fallback
) {
622 if (!sock_info
->wait_shm_mmap
) {
623 sock_info
->wait_shm_mmap
= get_map_shm(sock_info
);
624 if (!sock_info
->wait_shm_mmap
)
629 DBG("Waiting for %s apps sessiond", sock_info
->name
);
630 /* Wait for futex wakeup */
631 if (uatomic_read((int32_t *) sock_info
->wait_shm_mmap
) == 0) {
632 ret
= futex_async((int32_t *) sock_info
->wait_shm_mmap
,
633 FUTEX_WAIT
, 0, NULL
, NULL
, 0);
635 if (errno
== EFAULT
) {
636 wait_poll_fallback
= 1;
638 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
639 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
640 "Please upgrade your kernel "
641 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
642 "mainline). LTTng-UST will use polling mode fallback.");
660 * This thread does not allocate any resource, except within
661 * handle_message, within mutex protection. This mutex protects against
663 * The other moment it allocates resources is at socket connexion, which
664 * is also protected by the mutex.
667 void *ust_listener_thread(void *arg
)
669 struct sock_info
*sock_info
= arg
;
670 int sock
, ret
, prev_connect_failed
= 0, has_waited
= 0;
672 /* Restart trying to connect to the session daemon */
674 if (prev_connect_failed
) {
675 /* Wait for sessiond availability with pipe */
676 wait_for_sessiond(sock_info
);
680 * Sleep for 5 seconds before retrying after a
681 * sequence of failure / wait / failure. This
682 * deals with a killed or broken session daemon.
687 prev_connect_failed
= 0;
691 if (lttng_ust_comm_should_quit
) {
696 if (sock_info
->socket
!= -1) {
697 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
699 ERR("Error closing %s apps socket", sock_info
->name
);
701 sock_info
->socket
= -1;
705 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
);
707 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
708 prev_connect_failed
= 1;
710 * If we cannot find the sessiond daemon, don't delay
711 * constructor execution.
713 ret
= handle_register_done(sock_info
);
719 sock_info
->socket
= sock
= ret
;
722 * Create only one root handle per listener thread for the whole
725 if (sock_info
->root_handle
== -1) {
726 ret
= lttng_abi_create_root_handle();
728 ERR("Error creating root handle");
732 sock_info
->root_handle
= ret
;
735 ret
= register_app_to_sessiond(sock
);
737 ERR("Error registering to %s apps socket", sock_info
->name
);
738 prev_connect_failed
= 1;
740 * If we cannot register to the sessiond daemon, don't
741 * delay constructor execution.
743 ret
= handle_register_done(sock_info
);
752 struct ustcomm_ust_msg lum
;
754 len
= ustcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
756 case 0: /* orderly shutdown */
757 DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info
->name
);
760 * Either sessiond has shutdown or refused us by closing the socket.
761 * In either case, we don't want to delay construction execution,
762 * and we need to wait before retry.
764 prev_connect_failed
= 1;
766 * If we cannot register to the sessiond daemon, don't
767 * delay constructor execution.
769 ret
= handle_register_done(sock_info
);
774 DBG("message received\n");
775 ret
= handle_message(sock_info
, sock
, &lum
);
777 ERR("Error handling message for %s socket", sock_info
->name
);
781 DBG("Receive failed from lttng-sessiond with errno %d", errno
);
782 if (errno
== ECONNRESET
) {
783 ERR("%s remote end closed connection\n", sock_info
->name
);
788 ERR("incorrect message size (%s socket): %zd\n", sock_info
->name
, len
);
794 goto restart
; /* try to reconnect */
800 * Return values: -1: don't wait. 0: wait forever. 1: timeout wait.
803 int get_timeout(struct timespec
*constructor_timeout
)
805 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
809 str_delay
= getenv("LTTNG_UST_REGISTER_TIMEOUT");
811 constructor_delay_ms
= strtol(str_delay
, NULL
, 10);
814 switch (constructor_delay_ms
) {
815 case -1:/* fall-through */
817 return constructor_delay_ms
;
823 * If we are unable to find the current time, don't wait.
825 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
829 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
830 constructor_timeout
->tv_nsec
+=
831 (constructor_delay_ms
% 1000UL) * 1000000UL;
832 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
833 constructor_timeout
->tv_sec
++;
834 constructor_timeout
->tv_nsec
-= 1000000000UL;
840 * sessiond monitoring thread: monitor presence of global and per-user
841 * sessiond by polling the application common named pipe.
845 void __attribute__((constructor
)) lttng_ust_init(void)
847 struct timespec constructor_timeout
;
848 sigset_t sig_all_blocked
, orig_parent_mask
;
852 if (uatomic_xchg(&initialized
, 1) == 1)
856 * Fixup interdependency between TLS fixup mutex (which happens
857 * to be the dynamic linker mutex) and ust_lock, taken within
860 lttng_fixup_event_tls();
861 lttng_fixup_ringbuffer_tls();
862 lttng_fixup_vtid_tls();
865 * We want precise control over the order in which we construct
866 * our sub-libraries vs starting to receive commands from
867 * sessiond (otherwise leading to errors when trying to create
868 * sessiond before the init functions are completed).
872 ltt_ring_buffer_metadata_client_init();
873 ltt_ring_buffer_client_overwrite_init();
874 ltt_ring_buffer_client_discard_init();
876 timeout_mode
= get_timeout(&constructor_timeout
);
878 ret
= sem_init(&constructor_wait
, 0, 0);
881 ret
= setup_local_apps();
883 ERR("Error setting up to local apps");
886 /* A new thread created by pthread_create inherits the signal mask
887 * from the parent. To avoid any signal being received by the
888 * listener thread, we block all signals temporarily in the parent,
889 * while we create the listener thread.
891 sigfillset(&sig_all_blocked
);
892 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_parent_mask
);
894 ERR("pthread_sigmask: %s", strerror(ret
));
897 ret
= pthread_create(&global_apps
.ust_listener
, NULL
,
898 ust_listener_thread
, &global_apps
);
900 ERR("pthread_create global: %s", strerror(ret
));
902 if (local_apps
.allowed
) {
903 ret
= pthread_create(&local_apps
.ust_listener
, NULL
,
904 ust_listener_thread
, &local_apps
);
906 ERR("pthread_create local: %s", strerror(ret
));
909 handle_register_done(&local_apps
);
912 /* Restore original signal mask in parent */
913 ret
= pthread_sigmask(SIG_SETMASK
, &orig_parent_mask
, NULL
);
915 ERR("pthread_sigmask: %s", strerror(ret
));
918 switch (timeout_mode
) {
919 case 1: /* timeout wait */
921 ret
= sem_timedwait(&constructor_wait
,
922 &constructor_timeout
);
923 } while (ret
< 0 && errno
== EINTR
);
924 if (ret
< 0 && errno
== ETIMEDOUT
) {
925 ERR("Timed out waiting for ltt-sessiond");
930 case -1:/* wait forever */
932 ret
= sem_wait(&constructor_wait
);
933 } while (ret
< 0 && errno
== EINTR
);
936 case 0: /* no timeout */
942 void lttng_ust_cleanup(int exiting
)
944 cleanup_sock_info(&global_apps
, exiting
);
945 if (local_apps
.allowed
) {
946 cleanup_sock_info(&local_apps
, exiting
);
949 * The teardown in this function all affect data structures
950 * accessed under the UST lock by the listener thread. This
951 * lock, along with the lttng_ust_comm_should_quit flag, ensure
952 * that none of these threads are accessing this data at this
955 lttng_ust_abi_exit();
956 lttng_ust_events_exit();
957 ltt_ring_buffer_client_discard_exit();
958 ltt_ring_buffer_client_overwrite_exit();
959 ltt_ring_buffer_metadata_client_exit();
962 /* Reinitialize values for fork */
964 lttng_ust_comm_should_quit
= 0;
969 void __attribute__((destructor
)) lttng_ust_exit(void)
974 * Using pthread_cancel here because:
975 * A) we don't want to hang application teardown.
976 * B) the thread is not allocating any resource.
980 * Require the communication thread to quit. Synchronize with
981 * mutexes to ensure it is not in a mutex critical section when
982 * pthread_cancel is later called.
985 lttng_ust_comm_should_quit
= 1;
989 ret
= pthread_cancel(global_apps
.ust_listener
);
991 ERR("Error cancelling global ust listener thread: %s",
994 if (local_apps
.allowed
) {
995 ret
= pthread_cancel(local_apps
.ust_listener
);
997 ERR("Error cancelling local ust listener thread: %s",
1002 * Do NOT join threads: use of sys_futex makes it impossible to
1003 * join the threads without using async-cancel, but async-cancel
1004 * is delivered by a signal, which could hit the target thread
1005 * anywhere in its code path, including while the ust_lock() is
1006 * held, causing a deadlock for the other thread. Let the OS
1007 * cleanup the threads if there are stalled in a syscall.
1009 lttng_ust_cleanup(1);
1013 * We exclude the worker threads across fork and clone (except
1014 * CLONE_VM), because these system calls only keep the forking thread
1015 * running in the child. Therefore, we don't want to call fork or clone
1016 * in the middle of an tracepoint or ust tracing state modification.
1017 * Holding this mutex protects these structures across fork and clone.
1019 void ust_before_fork(sigset_t
*save_sigset
)
1022 * Disable signals. This is to avoid that the child intervenes
1023 * before it is properly setup for tracing. It is safer to
1024 * disable all signals, because then we know we are not breaking
1025 * anything by restoring the original mask.
1030 if (lttng_ust_nest_count
)
1032 /* Disable signals */
1033 sigfillset(&all_sigs
);
1034 ret
= sigprocmask(SIG_BLOCK
, &all_sigs
, save_sigset
);
1036 PERROR("sigprocmask");
1039 rcu_bp_before_fork();
1042 static void ust_after_fork_common(sigset_t
*restore_sigset
)
1046 DBG("process %d", getpid());
1048 /* Restore signals */
1049 ret
= sigprocmask(SIG_SETMASK
, restore_sigset
, NULL
);
1051 PERROR("sigprocmask");
1055 void ust_after_fork_parent(sigset_t
*restore_sigset
)
1057 if (lttng_ust_nest_count
)
1059 DBG("process %d", getpid());
1060 rcu_bp_after_fork_parent();
1061 /* Release mutexes and reenable signals */
1062 ust_after_fork_common(restore_sigset
);
1066 * After fork, in the child, we need to cleanup all the leftover state,
1067 * except the worker thread which already magically disappeared thanks
1068 * to the weird Linux fork semantics. After tyding up, we call
1069 * lttng_ust_init() again to start over as a new PID.
1071 * This is meant for forks() that have tracing in the child between the
1072 * fork and following exec call (if there is any).
1074 void ust_after_fork_child(sigset_t
*restore_sigset
)
1076 if (lttng_ust_nest_count
)
1078 DBG("process %d", getpid());
1079 /* Release urcu mutexes */
1080 rcu_bp_after_fork_child();
1081 lttng_ust_cleanup(0);
1082 lttng_context_vtid_reset();
1083 /* Release mutexes and reenable signals */
1084 ust_after_fork_common(restore_sigset
);