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
24 #include <sys/types.h>
25 #include <sys/socket.h>
28 #include <sys/types.h>
34 #include <semaphore.h>
39 #include <urcu/uatomic.h>
40 #include <urcu/futex.h>
41 #include <urcu/compiler.h>
43 #include <lttng/ust-events.h>
44 #include <lttng/ust-abi.h>
45 #include <lttng/ust.h>
46 #include <lttng/ust-error.h>
47 #include <lttng/ust-ctl.h>
48 #include <urcu/tls-compat.h>
51 #include <usterr-signal-safe.h>
53 #include "tracepoint-internal.h"
54 #include "lttng-tracer-core.h"
56 #include "../libringbuffer/rb-init.h"
57 #include "lttng-ust-statedump.h"
59 #include "../libringbuffer/getcpu.h"
63 * Has lttng ust comm constructor been called ?
65 static int initialized
;
68 * The ust_lock/ust_unlock lock is used as a communication thread mutex.
69 * Held when handling a command, also held by fork() to deal with
70 * removal of threads, and by exit path.
72 * The UST lock is the centralized mutex across UST tracing control and
75 * ust_exit_mutex must never nest in ust_mutex.
77 * ust_fork_mutex must never nest in ust_mutex.
79 * ust_mutex_nest is a per-thread nesting counter, allowing the perf
80 * counter lazy initialization called by events within the statedump,
81 * which traces while the ust_mutex is held.
83 * ust_lock nests within the dynamic loader lock (within glibc) because
84 * it is taken within the library constructor.
86 * The ust fd tracker lock nests within the ust_mutex.
88 static pthread_mutex_t ust_mutex
= PTHREAD_MUTEX_INITIALIZER
;
90 /* Allow nesting the ust_mutex within the same thread. */
91 static DEFINE_URCU_TLS(int, ust_mutex_nest
);
94 * ust_exit_mutex protects thread_active variable wrt thread exit. It
95 * cannot be done by ust_mutex because pthread_cancel(), which takes an
96 * internal libc lock, cannot nest within ust_mutex.
98 * It never nests within a ust_mutex.
100 static pthread_mutex_t ust_exit_mutex
= PTHREAD_MUTEX_INITIALIZER
;
103 * ust_fork_mutex protects base address statedump tracing against forks. It
104 * prevents the dynamic loader lock to be taken (by base address statedump
105 * tracing) while a fork is happening, thus preventing deadlock issues with
106 * the dynamic loader lock.
108 static pthread_mutex_t ust_fork_mutex
= PTHREAD_MUTEX_INITIALIZER
;
110 /* Should the ust comm thread quit ? */
111 static int lttng_ust_comm_should_quit
;
114 * This variable can be tested by applications to check whether
115 * lttng-ust is loaded. They simply have to define their own
116 * "lttng_ust_loaded" weak symbol, and test it. It is set to 1 by the
117 * library constructor.
119 int lttng_ust_loaded
__attribute__((weak
));
122 * Return 0 on success, -1 if should quit.
123 * The lock is taken in both cases.
128 sigset_t sig_all_blocked
, orig_mask
;
131 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
133 ERR("pthread_setcancelstate: %s", strerror(ret
));
135 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
136 ERR("pthread_setcancelstate: unexpected oldstate");
138 sigfillset(&sig_all_blocked
);
139 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
141 ERR("pthread_sigmask: %s", strerror(ret
));
143 if (!URCU_TLS(ust_mutex_nest
)++)
144 pthread_mutex_lock(&ust_mutex
);
145 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
147 ERR("pthread_sigmask: %s", strerror(ret
));
149 if (lttng_ust_comm_should_quit
) {
157 * ust_lock_nocheck() can be used in constructors/destructors, because
158 * they are already nested within the dynamic loader lock, and therefore
159 * have exclusive access against execution of liblttng-ust destructor.
162 void ust_lock_nocheck(void)
164 sigset_t sig_all_blocked
, orig_mask
;
167 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
169 ERR("pthread_setcancelstate: %s", strerror(ret
));
171 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
172 ERR("pthread_setcancelstate: unexpected oldstate");
174 sigfillset(&sig_all_blocked
);
175 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
177 ERR("pthread_sigmask: %s", strerror(ret
));
179 if (!URCU_TLS(ust_mutex_nest
)++)
180 pthread_mutex_lock(&ust_mutex
);
181 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
183 ERR("pthread_sigmask: %s", strerror(ret
));
190 void ust_unlock(void)
192 sigset_t sig_all_blocked
, orig_mask
;
195 sigfillset(&sig_all_blocked
);
196 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
198 ERR("pthread_sigmask: %s", strerror(ret
));
200 if (!--URCU_TLS(ust_mutex_nest
))
201 pthread_mutex_unlock(&ust_mutex
);
202 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
204 ERR("pthread_sigmask: %s", strerror(ret
));
206 ret
= pthread_setcancelstate(PTHREAD_CANCEL_ENABLE
, &oldstate
);
208 ERR("pthread_setcancelstate: %s", strerror(ret
));
210 if (oldstate
!= PTHREAD_CANCEL_DISABLE
) {
211 ERR("pthread_setcancelstate: unexpected oldstate");
216 * Wait for either of these before continuing to the main
218 * - the register_done message from sessiond daemon
219 * (will let the sessiond daemon enable sessions before main
221 * - sessiond daemon is not reachable.
222 * - timeout (ensuring applications are resilient to session
225 static sem_t constructor_wait
;
227 * Doing this for both the global and local sessiond.
230 sem_count_initial_value
= 4,
233 static int sem_count
= sem_count_initial_value
;
236 * Counting nesting within lttng-ust. Used to ensure that calling fork()
237 * from liblttng-ust does not execute the pre/post fork handlers.
239 static DEFINE_URCU_TLS(int, lttng_ust_nest_count
);
242 * Info about socket and associated listener thread.
246 pthread_t ust_listener
; /* listener thread */
248 int registration_done
;
253 char sock_path
[PATH_MAX
];
257 char wait_shm_path
[PATH_MAX
];
259 /* Keep track of lazy state dump not performed yet. */
260 int statedump_pending
;
261 int initial_statedump_done
;
264 /* Socket from app (connect) to session daemon (listen) for communication */
265 struct sock_info global_apps
= {
270 .registration_done
= 0,
274 .sock_path
= LTTNG_DEFAULT_RUNDIR
"/" LTTNG_UST_SOCK_FILENAME
,
278 .wait_shm_path
= "/" LTTNG_UST_WAIT_FILENAME
,
280 .statedump_pending
= 0,
281 .initial_statedump_done
= 0,
284 /* TODO: allow global_apps_sock_path override */
286 struct sock_info local_apps
= {
290 .registration_done
= 0,
291 .allowed
= 0, /* Check setuid bit first */
297 .statedump_pending
= 0,
298 .initial_statedump_done
= 0,
301 static int wait_poll_fallback
;
303 static const char *cmd_name_mapping
[] = {
304 [ LTTNG_UST_RELEASE
] = "Release",
305 [ LTTNG_UST_SESSION
] = "Create Session",
306 [ LTTNG_UST_TRACER_VERSION
] = "Get Tracer Version",
308 [ LTTNG_UST_TRACEPOINT_LIST
] = "Create Tracepoint List",
309 [ LTTNG_UST_WAIT_QUIESCENT
] = "Wait for Quiescent State",
310 [ LTTNG_UST_REGISTER_DONE
] = "Registration Done",
311 [ LTTNG_UST_TRACEPOINT_FIELD_LIST
] = "Create Tracepoint Field List",
313 /* Session FD commands */
314 [ LTTNG_UST_CHANNEL
] = "Create Channel",
315 [ LTTNG_UST_SESSION_START
] = "Start Session",
316 [ LTTNG_UST_SESSION_STOP
] = "Stop Session",
318 /* Channel FD commands */
319 [ LTTNG_UST_STREAM
] = "Create Stream",
320 [ LTTNG_UST_EVENT
] = "Create Event",
322 /* Event and Channel FD commands */
323 [ LTTNG_UST_CONTEXT
] = "Create Context",
324 [ LTTNG_UST_FLUSH_BUFFER
] = "Flush Buffer",
326 /* Event, Channel and Session commands */
327 [ LTTNG_UST_ENABLE
] = "Enable",
328 [ LTTNG_UST_DISABLE
] = "Disable",
330 /* Tracepoint list commands */
331 [ LTTNG_UST_TRACEPOINT_LIST_GET
] = "List Next Tracepoint",
332 [ LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
] = "List Next Tracepoint Field",
334 /* Event FD commands */
335 [ LTTNG_UST_FILTER
] = "Create Filter",
336 [ LTTNG_UST_EXCLUSION
] = "Add exclusions to event",
339 static const char *str_timeout
;
340 static int got_timeout_env
;
342 extern void lttng_ring_buffer_client_overwrite_init(void);
343 extern void lttng_ring_buffer_client_overwrite_rt_init(void);
344 extern void lttng_ring_buffer_client_discard_init(void);
345 extern void lttng_ring_buffer_client_discard_rt_init(void);
346 extern void lttng_ring_buffer_metadata_client_init(void);
347 extern void lttng_ring_buffer_client_overwrite_exit(void);
348 extern void lttng_ring_buffer_client_overwrite_rt_exit(void);
349 extern void lttng_ring_buffer_client_discard_exit(void);
350 extern void lttng_ring_buffer_client_discard_rt_exit(void);
351 extern void lttng_ring_buffer_metadata_client_exit(void);
353 static char *get_map_shm(struct sock_info
*sock_info
);
355 ssize_t
lttng_ust_read(int fd
, void *buf
, size_t len
)
358 size_t copied
= 0, to_copy
= len
;
361 ret
= read(fd
, buf
+ copied
, to_copy
);
366 } while ((ret
> 0 && to_copy
> 0)
367 || (ret
< 0 && errno
== EINTR
));
374 * Returns the HOME directory path. Caller MUST NOT free(3) the returned
378 const char *get_lttng_home_dir(void)
382 val
= (const char *) lttng_getenv("LTTNG_HOME");
386 return (const char *) lttng_getenv("HOME");
390 * Force a read (imply TLS fixup for dlopen) of TLS variables.
393 void lttng_fixup_nest_count_tls(void)
395 asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count
)));
399 void lttng_fixup_ust_mutex_nest_tls(void)
401 asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest
)));
408 void lttng_fixup_urcu_bp_tls(void)
414 void lttng_ust_fixup_tls(void)
416 lttng_fixup_urcu_bp_tls();
417 lttng_fixup_ringbuffer_tls();
418 lttng_fixup_vtid_tls();
419 lttng_fixup_nest_count_tls();
420 lttng_fixup_procname_tls();
421 lttng_fixup_ust_mutex_nest_tls();
422 lttng_ust_fixup_fd_tracker_tls();
425 int lttng_get_notify_socket(void *owner
)
427 struct sock_info
*info
= owner
;
429 return info
->notify_socket
;
433 void print_cmd(int cmd
, int handle
)
435 const char *cmd_name
= "Unknown";
437 if (cmd
>= 0 && cmd
< LTTNG_ARRAY_SIZE(cmd_name_mapping
)
438 && cmd_name_mapping
[cmd
]) {
439 cmd_name
= cmd_name_mapping
[cmd
];
441 DBG("Message Received \"%s\" (%d), Handle \"%s\" (%d)",
443 lttng_ust_obj_get_name(handle
), handle
);
447 int setup_global_apps(void)
450 assert(!global_apps
.wait_shm_mmap
);
452 global_apps
.wait_shm_mmap
= get_map_shm(&global_apps
);
453 if (!global_apps
.wait_shm_mmap
) {
454 WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
455 global_apps
.allowed
= 0;
460 global_apps
.allowed
= 1;
465 int setup_local_apps(void)
468 const char *home_dir
;
471 assert(!local_apps
.wait_shm_mmap
);
475 * Disallow per-user tracing for setuid binaries.
477 if (uid
!= geteuid()) {
478 assert(local_apps
.allowed
== 0);
482 home_dir
= get_lttng_home_dir();
484 WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
485 assert(local_apps
.allowed
== 0);
489 local_apps
.allowed
= 1;
490 snprintf(local_apps
.sock_path
, PATH_MAX
, "%s/%s/%s",
492 LTTNG_DEFAULT_HOME_RUNDIR
,
493 LTTNG_UST_SOCK_FILENAME
);
494 snprintf(local_apps
.wait_shm_path
, PATH_MAX
, "/%s-%u",
495 LTTNG_UST_WAIT_FILENAME
,
498 local_apps
.wait_shm_mmap
= get_map_shm(&local_apps
);
499 if (!local_apps
.wait_shm_mmap
) {
500 WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
501 local_apps
.allowed
= 0;
510 * Get socket timeout, in ms.
511 * -1: wait forever. 0: don't wait. >0: timeout, in ms.
514 long get_timeout(void)
516 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
518 if (!got_timeout_env
) {
519 str_timeout
= lttng_getenv("LTTNG_UST_REGISTER_TIMEOUT");
523 constructor_delay_ms
= strtol(str_timeout
, NULL
, 10);
524 /* All negative values are considered as "-1". */
525 if (constructor_delay_ms
< -1)
526 constructor_delay_ms
= -1;
527 return constructor_delay_ms
;
530 /* Timeout for notify socket send and recv. */
532 long get_notify_sock_timeout(void)
534 return get_timeout();
537 /* Timeout for connecting to cmd and notify sockets. */
539 long get_connect_sock_timeout(void)
541 return get_timeout();
545 * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
548 int get_constructor_timeout(struct timespec
*constructor_timeout
)
550 long constructor_delay_ms
;
553 constructor_delay_ms
= get_timeout();
555 switch (constructor_delay_ms
) {
556 case -1:/* fall-through */
558 return constructor_delay_ms
;
564 * If we are unable to find the current time, don't wait.
566 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
571 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
572 constructor_timeout
->tv_nsec
+=
573 (constructor_delay_ms
% 1000UL) * 1000000UL;
574 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
575 constructor_timeout
->tv_sec
++;
576 constructor_timeout
->tv_nsec
-= 1000000000UL;
578 /* Timeout wait (constructor_delay_ms). */
583 void get_allow_blocking(void)
585 const char *str_allow_blocking
=
586 lttng_getenv("LTTNG_UST_ALLOW_BLOCKING");
588 if (str_allow_blocking
) {
589 DBG("%s environment variable is set",
590 "LTTNG_UST_ALLOW_BLOCKING");
591 lttng_ust_ringbuffer_set_allow_blocking();
596 int register_to_sessiond(int socket
, enum ustctl_socket_type type
)
598 return ustcomm_send_reg_msg(socket
,
601 lttng_alignof(uint8_t) * CHAR_BIT
,
602 lttng_alignof(uint16_t) * CHAR_BIT
,
603 lttng_alignof(uint32_t) * CHAR_BIT
,
604 lttng_alignof(uint64_t) * CHAR_BIT
,
605 lttng_alignof(unsigned long) * CHAR_BIT
);
609 int send_reply(int sock
, struct ustcomm_ust_reply
*lur
)
613 len
= ustcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
616 DBG("message successfully sent");
619 if (len
== -ECONNRESET
) {
620 DBG("remote end closed connection");
625 DBG("incorrect message size: %zd", len
);
631 void decrement_sem_count(unsigned int count
)
635 assert(uatomic_read(&sem_count
) >= count
);
637 if (uatomic_read(&sem_count
) <= 0) {
641 ret
= uatomic_add_return(&sem_count
, -count
);
643 ret
= sem_post(&constructor_wait
);
649 int handle_register_done(struct sock_info
*sock_info
)
651 if (sock_info
->registration_done
)
653 sock_info
->registration_done
= 1;
655 decrement_sem_count(1);
656 if (!sock_info
->statedump_pending
) {
657 sock_info
->initial_statedump_done
= 1;
658 decrement_sem_count(1);
665 int handle_register_failed(struct sock_info
*sock_info
)
667 if (sock_info
->registration_done
)
669 sock_info
->registration_done
= 1;
670 sock_info
->initial_statedump_done
= 1;
672 decrement_sem_count(2);
678 * Only execute pending statedump after the constructor semaphore has
679 * been posted by the current listener thread. This means statedump will
680 * only be performed after the "registration done" command is received
681 * from this thread's session daemon.
683 * This ensures we don't run into deadlock issues with the dynamic
684 * loader mutex, which is held while the constructor is called and
685 * waiting on the constructor semaphore. All operations requiring this
686 * dynamic loader lock need to be postponed using this mechanism.
688 * In a scenario with two session daemons connected to the application,
689 * it is possible that the first listener thread which receives the
690 * registration done command issues its statedump while the dynamic
691 * loader lock is still held by the application constructor waiting on
692 * the semaphore. It will however be allowed to proceed when the
693 * second session daemon sends the registration done command to the
694 * second listener thread. This situation therefore does not produce
698 void handle_pending_statedump(struct sock_info
*sock_info
)
700 if (sock_info
->registration_done
&& sock_info
->statedump_pending
) {
701 sock_info
->statedump_pending
= 0;
702 pthread_mutex_lock(&ust_fork_mutex
);
703 lttng_handle_pending_statedump(sock_info
);
704 pthread_mutex_unlock(&ust_fork_mutex
);
706 if (!sock_info
->initial_statedump_done
) {
707 sock_info
->initial_statedump_done
= 1;
708 decrement_sem_count(1);
714 int handle_message(struct sock_info
*sock_info
,
715 int sock
, struct ustcomm_ust_msg
*lum
)
718 const struct lttng_ust_objd_ops
*ops
;
719 struct ustcomm_ust_reply lur
;
721 char ctxstr
[LTTNG_UST_SYM_NAME_LEN
]; /* App context string. */
724 memset(&lur
, 0, sizeof(lur
));
727 ret
= -LTTNG_UST_ERR_EXITING
;
731 ops
= objd_ops(lum
->handle
);
738 case LTTNG_UST_REGISTER_DONE
:
739 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
740 ret
= handle_register_done(sock_info
);
744 case LTTNG_UST_RELEASE
:
745 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
748 ret
= lttng_ust_objd_unref(lum
->handle
, 1);
750 case LTTNG_UST_FILTER
:
752 /* Receive filter data */
753 struct lttng_ust_filter_bytecode_node
*bytecode
;
755 if (lum
->u
.filter
.data_size
> FILTER_BYTECODE_MAX_LEN
) {
756 ERR("Filter data size is too large: %u bytes",
757 lum
->u
.filter
.data_size
);
762 if (lum
->u
.filter
.reloc_offset
> lum
->u
.filter
.data_size
) {
763 ERR("Filter reloc offset %u is not within data",
764 lum
->u
.filter
.reloc_offset
);
769 bytecode
= zmalloc(sizeof(*bytecode
) + lum
->u
.filter
.data_size
);
774 len
= ustcomm_recv_unix_sock(sock
, bytecode
->bc
.data
,
775 lum
->u
.filter
.data_size
);
777 case 0: /* orderly shutdown */
782 if (len
== lum
->u
.filter
.data_size
) {
783 DBG("filter data received");
785 } else if (len
< 0) {
786 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
787 if (len
== -ECONNRESET
) {
788 ERR("%s remote end closed connection", sock_info
->name
);
797 DBG("incorrect filter data message size: %zd", len
);
803 bytecode
->bc
.len
= lum
->u
.filter
.data_size
;
804 bytecode
->bc
.reloc_offset
= lum
->u
.filter
.reloc_offset
;
805 bytecode
->bc
.seqnum
= lum
->u
.filter
.seqnum
;
807 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
808 (unsigned long) bytecode
,
813 /* don't free bytecode if everything went fine. */
820 case LTTNG_UST_EXCLUSION
:
822 /* Receive exclusion names */
823 struct lttng_ust_excluder_node
*node
;
826 count
= lum
->u
.exclusion
.count
;
828 /* There are no names to read */
832 node
= zmalloc(sizeof(*node
) +
833 count
* LTTNG_UST_SYM_NAME_LEN
);
838 node
->excluder
.count
= count
;
839 len
= ustcomm_recv_unix_sock(sock
, node
->excluder
.names
,
840 count
* LTTNG_UST_SYM_NAME_LEN
);
842 case 0: /* orderly shutdown */
847 if (len
== count
* LTTNG_UST_SYM_NAME_LEN
) {
848 DBG("Exclusion data received");
850 } else if (len
< 0) {
851 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
852 if (len
== -ECONNRESET
) {
853 ERR("%s remote end closed connection", sock_info
->name
);
862 DBG("Incorrect exclusion data message size: %zd", len
);
869 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
870 (unsigned long) node
,
875 /* Don't free exclusion data if everything went fine. */
882 case LTTNG_UST_CHANNEL
:
887 len
= ustcomm_recv_channel_from_sessiond(sock
,
888 &chan_data
, lum
->u
.channel
.len
,
891 case 0: /* orderly shutdown */
895 if (len
== lum
->u
.channel
.len
) {
896 DBG("channel data received");
898 } else if (len
< 0) {
899 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
900 if (len
== -ECONNRESET
) {
901 ERR("%s remote end closed connection", sock_info
->name
);
908 DBG("incorrect channel data message size: %zd", len
);
913 args
.channel
.chan_data
= chan_data
;
914 args
.channel
.wakeup_fd
= wakeup_fd
;
916 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
917 (unsigned long) &lum
->u
,
923 case LTTNG_UST_STREAM
:
925 /* Receive shm_fd, wakeup_fd */
926 ret
= ustcomm_recv_stream_from_sessiond(sock
,
929 &args
.stream
.wakeup_fd
);
935 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
936 (unsigned long) &lum
->u
,
942 case LTTNG_UST_CONTEXT
:
943 switch (lum
->u
.context
.ctx
) {
944 case LTTNG_UST_CONTEXT_APP_CONTEXT
:
947 size_t ctxlen
, recvlen
;
949 ctxlen
= strlen("$app.") + lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1
950 + strlen(":") + lum
->u
.context
.u
.app_ctx
.ctx_name_len
;
951 if (ctxlen
>= LTTNG_UST_SYM_NAME_LEN
) {
952 ERR("Application context string length size is too large: %zu bytes",
957 strcpy(ctxstr
, "$app.");
958 p
= &ctxstr
[strlen("$app.")];
959 recvlen
= ctxlen
- strlen("$app.");
960 len
= ustcomm_recv_unix_sock(sock
, p
, recvlen
);
962 case 0: /* orderly shutdown */
966 if (len
== recvlen
) {
967 DBG("app context data received");
969 } else if (len
< 0) {
970 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
971 if (len
== -ECONNRESET
) {
972 ERR("%s remote end closed connection", sock_info
->name
);
979 DBG("incorrect app context data message size: %zd", len
);
984 /* Put : between provider and ctxname. */
985 p
[lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1] = ':';
986 args
.app_context
.ctxname
= ctxstr
;
993 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
994 (unsigned long) &lum
->u
,
1002 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1003 (unsigned long) &lum
->u
,
1010 lur
.handle
= lum
->handle
;
1014 lur
.ret_code
= LTTNG_UST_OK
;
1017 * Use -LTTNG_UST_ERR as wildcard for UST internal
1018 * error that are not caused by the transport, except if
1019 * we already have a more precise error message to
1022 if (ret
> -LTTNG_UST_ERR
) {
1023 /* Translate code to UST error. */
1026 lur
.ret_code
= -LTTNG_UST_ERR_EXIST
;
1029 lur
.ret_code
= -LTTNG_UST_ERR_INVAL
;
1032 lur
.ret_code
= -LTTNG_UST_ERR_NOENT
;
1035 lur
.ret_code
= -LTTNG_UST_ERR_PERM
;
1038 lur
.ret_code
= -LTTNG_UST_ERR_NOSYS
;
1041 lur
.ret_code
= -LTTNG_UST_ERR
;
1050 case LTTNG_UST_TRACER_VERSION
:
1051 lur
.u
.version
= lum
->u
.version
;
1053 case LTTNG_UST_TRACEPOINT_LIST_GET
:
1054 memcpy(&lur
.u
.tracepoint
, &lum
->u
.tracepoint
, sizeof(lur
.u
.tracepoint
));
1058 DBG("Return value: %d", lur
.ret_val
);
1063 * Performed delayed statedump operations outside of the UST
1064 * lock. We need to take the dynamic loader lock before we take
1065 * the UST lock internally within handle_pending_statedump().
1067 handle_pending_statedump(sock_info
);
1070 ret
= -LTTNG_UST_ERR_EXITING
;
1074 ret
= send_reply(sock
, &lur
);
1076 DBG("error sending reply");
1081 * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field
1084 if (lur
.ret_code
== LTTNG_UST_OK
) {
1086 case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
:
1087 len
= ustcomm_send_unix_sock(sock
,
1088 &args
.field_list
.entry
,
1089 sizeof(args
.field_list
.entry
));
1094 if (len
!= sizeof(args
.field_list
.entry
)) {
1108 void cleanup_sock_info(struct sock_info
*sock_info
, int exiting
)
1112 if (sock_info
->root_handle
!= -1) {
1113 ret
= lttng_ust_objd_unref(sock_info
->root_handle
, 1);
1115 ERR("Error unref root handle");
1117 sock_info
->root_handle
= -1;
1119 sock_info
->registration_done
= 0;
1120 sock_info
->initial_statedump_done
= 0;
1123 * wait_shm_mmap, socket and notify socket are used by listener
1124 * threads outside of the ust lock, so we cannot tear them down
1125 * ourselves, because we cannot join on these threads. Leave
1126 * responsibility of cleaning up these resources to the OS
1132 if (sock_info
->socket
!= -1) {
1133 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1135 ERR("Error closing ust cmd socket");
1137 sock_info
->socket
= -1;
1139 if (sock_info
->notify_socket
!= -1) {
1140 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1142 ERR("Error closing ust notify socket");
1144 sock_info
->notify_socket
= -1;
1146 if (sock_info
->wait_shm_mmap
) {
1149 page_size
= sysconf(_SC_PAGE_SIZE
);
1150 if (page_size
<= 0) {
1154 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1156 ret
= munmap(sock_info
->wait_shm_mmap
, page_size
);
1158 ERR("Error unmapping wait shm");
1161 sock_info
->wait_shm_mmap
= NULL
;
1166 * Using fork to set umask in the child process (not multi-thread safe).
1167 * We deal with the shm_open vs ftruncate race (happening when the
1168 * sessiond owns the shm and does not let everybody modify it, to ensure
1169 * safety against shm_unlink) by simply letting the mmap fail and
1170 * retrying after a few seconds.
1171 * For global shm, everybody has rw access to it until the sessiond
1175 int get_wait_shm(struct sock_info
*sock_info
, size_t mmap_size
)
1177 int wait_shm_fd
, ret
;
1181 * Try to open read-only.
1183 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1184 if (wait_shm_fd
>= 0) {
1187 size_t bytes_read
= 0;
1190 * Try to read the fd. If unable to do so, try opening
1194 len
= read(wait_shm_fd
,
1195 &((char *) &tmp_read
)[bytes_read
],
1196 sizeof(tmp_read
) - bytes_read
);
1200 } while ((len
< 0 && errno
== EINTR
)
1201 || (len
> 0 && bytes_read
< sizeof(tmp_read
)));
1202 if (bytes_read
!= sizeof(tmp_read
)) {
1203 ret
= close(wait_shm_fd
);
1205 ERR("close wait_shm_fd");
1210 } else if (wait_shm_fd
< 0 && errno
!= ENOENT
) {
1212 * Real-only open did not work, and it's not because the
1213 * entry was not present. It's a failure that prohibits
1216 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1222 * If the open failed because the file did not exist, or because
1223 * the file was not truncated yet, try creating it ourself.
1225 URCU_TLS(lttng_ust_nest_count
)++;
1227 URCU_TLS(lttng_ust_nest_count
)--;
1232 * Parent: wait for child to return, in which case the
1233 * shared memory map will have been created.
1235 pid
= wait(&status
);
1236 if (pid
< 0 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0) {
1241 * Try to open read-only again after creation.
1243 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1244 if (wait_shm_fd
< 0) {
1246 * Real-only open did not work. It's a failure
1247 * that prohibits using shm.
1249 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1253 } else if (pid
== 0) {
1257 create_mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
;
1258 if (sock_info
->global
)
1259 create_mode
|= S_IROTH
| S_IWGRP
| S_IWOTH
;
1261 * We're alone in a child process, so we can modify the
1262 * process-wide umask.
1264 umask(~create_mode
);
1266 * Try creating shm (or get rw access).
1267 * We don't do an exclusive open, because we allow other
1268 * processes to create+ftruncate it concurrently.
1270 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
,
1271 O_RDWR
| O_CREAT
, create_mode
);
1272 if (wait_shm_fd
>= 0) {
1273 ret
= ftruncate(wait_shm_fd
, mmap_size
);
1275 PERROR("ftruncate");
1276 _exit(EXIT_FAILURE
);
1278 _exit(EXIT_SUCCESS
);
1281 * For local shm, we need to have rw access to accept
1282 * opening it: this means the local sessiond will be
1283 * able to wake us up. For global shm, we open it even
1284 * if rw access is not granted, because the root.root
1285 * sessiond will be able to override all rights and wake
1288 if (!sock_info
->global
&& errno
!= EACCES
) {
1289 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1290 _exit(EXIT_FAILURE
);
1293 * The shm exists, but we cannot open it RW. Report
1296 _exit(EXIT_SUCCESS
);
1301 if (wait_shm_fd
>= 0 && !sock_info
->global
) {
1302 struct stat statbuf
;
1305 * Ensure that our user is the owner of the shm file for
1306 * local shm. If we do not own the file, it means our
1307 * sessiond will not have access to wake us up (there is
1308 * probably a rogue process trying to fake our
1309 * sessiond). Fallback to polling method in this case.
1311 ret
= fstat(wait_shm_fd
, &statbuf
);
1316 if (statbuf
.st_uid
!= getuid())
1322 ret
= close(wait_shm_fd
);
1324 PERROR("Error closing fd");
1330 char *get_map_shm(struct sock_info
*sock_info
)
1333 int wait_shm_fd
, ret
;
1334 char *wait_shm_mmap
;
1336 page_size
= sysconf(_SC_PAGE_SIZE
);
1337 if (page_size
<= 0) {
1341 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1345 lttng_ust_lock_fd_tracker();
1346 wait_shm_fd
= get_wait_shm(sock_info
, page_size
);
1347 if (wait_shm_fd
< 0) {
1348 lttng_ust_unlock_fd_tracker();
1352 ret
= lttng_ust_add_fd_to_tracker(wait_shm_fd
);
1354 ret
= close(wait_shm_fd
);
1356 PERROR("Error closing fd");
1358 lttng_ust_unlock_fd_tracker();
1363 lttng_ust_unlock_fd_tracker();
1365 wait_shm_mmap
= mmap(NULL
, page_size
, PROT_READ
,
1366 MAP_SHARED
, wait_shm_fd
, 0);
1368 /* close shm fd immediately after taking the mmap reference */
1369 lttng_ust_lock_fd_tracker();
1370 ret
= close(wait_shm_fd
);
1372 lttng_ust_delete_fd_from_tracker(wait_shm_fd
);
1374 PERROR("Error closing fd");
1376 lttng_ust_unlock_fd_tracker();
1378 if (wait_shm_mmap
== MAP_FAILED
) {
1379 DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
1382 return wait_shm_mmap
;
1389 void wait_for_sessiond(struct sock_info
*sock_info
)
1391 /* Use ust_lock to check if we should quit. */
1395 if (wait_poll_fallback
) {
1400 assert(sock_info
->wait_shm_mmap
);
1402 DBG("Waiting for %s apps sessiond", sock_info
->name
);
1403 /* Wait for futex wakeup */
1404 if (uatomic_read((int32_t *) sock_info
->wait_shm_mmap
))
1407 while (futex_async((int32_t *) sock_info
->wait_shm_mmap
,
1408 FUTEX_WAIT
, 0, NULL
, NULL
, 0)) {
1411 /* Value already changed. */
1414 /* Retry if interrupted by signal. */
1415 break; /* Get out of switch. */
1417 wait_poll_fallback
= 1;
1419 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
1420 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
1421 "Please upgrade your kernel "
1422 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
1423 "mainline). LTTng-UST will use polling mode fallback.");
1442 * This thread does not allocate any resource, except within
1443 * handle_message, within mutex protection. This mutex protects against
1445 * The other moment it allocates resources is at socket connection, which
1446 * is also protected by the mutex.
1449 void *ust_listener_thread(void *arg
)
1451 struct sock_info
*sock_info
= arg
;
1452 int sock
, ret
, prev_connect_failed
= 0, has_waited
= 0, fd
;
1455 lttng_ust_fixup_tls();
1457 * If available, add '-ust' to the end of this thread's
1460 ret
= lttng_ust_setustprocname();
1462 ERR("Unable to set UST process name");
1465 /* Restart trying to connect to the session daemon */
1467 if (prev_connect_failed
) {
1468 /* Wait for sessiond availability with pipe */
1469 wait_for_sessiond(sock_info
);
1473 * Sleep for 5 seconds before retrying after a
1474 * sequence of failure / wait / failure. This
1475 * deals with a killed or broken session daemon.
1481 prev_connect_failed
= 0;
1488 if (sock_info
->socket
!= -1) {
1489 /* FD tracker is updated by ustcomm_close_unix_sock() */
1490 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1492 ERR("Error closing %s ust cmd socket",
1495 sock_info
->socket
= -1;
1497 if (sock_info
->notify_socket
!= -1) {
1498 /* FD tracker is updated by ustcomm_close_unix_sock() */
1499 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1501 ERR("Error closing %s ust notify socket",
1504 sock_info
->notify_socket
= -1;
1509 * Register. We need to perform both connect and sending
1510 * registration message before doing the next connect otherwise
1511 * we may reach unix socket connect queue max limits and block
1512 * on the 2nd connect while the session daemon is awaiting the
1513 * first connect registration message.
1515 /* Connect cmd socket */
1516 lttng_ust_lock_fd_tracker();
1517 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1518 get_connect_sock_timeout());
1520 lttng_ust_unlock_fd_tracker();
1521 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1522 prev_connect_failed
= 1;
1525 * If we cannot find the sessiond daemon, don't delay
1526 * constructor execution.
1528 ret
= handle_register_failed(sock_info
);
1534 ret
= lttng_ust_add_fd_to_tracker(fd
);
1538 PERROR("close on sock_info->socket");
1541 lttng_ust_unlock_fd_tracker();
1546 sock_info
->socket
= ret
;
1547 lttng_ust_unlock_fd_tracker();
1551 * Unlock/relock ust lock because connect is blocking (with
1552 * timeout). Don't delay constructors on the ust lock for too
1560 * Create only one root handle per listener thread for the whole
1561 * process lifetime, so we ensure we get ID which is statically
1562 * assigned to the root handle.
1564 if (sock_info
->root_handle
== -1) {
1565 ret
= lttng_abi_create_root_handle();
1567 ERR("Error creating root handle");
1570 sock_info
->root_handle
= ret
;
1573 ret
= register_to_sessiond(sock_info
->socket
, USTCTL_SOCKET_CMD
);
1575 ERR("Error registering to %s ust cmd socket",
1577 prev_connect_failed
= 1;
1579 * If we cannot register to the sessiond daemon, don't
1580 * delay constructor execution.
1582 ret
= handle_register_failed(sock_info
);
1590 * Unlock/relock ust lock because connect is blocking (with
1591 * timeout). Don't delay constructors on the ust lock for too
1598 /* Connect notify socket */
1599 lttng_ust_lock_fd_tracker();
1600 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1601 get_connect_sock_timeout());
1603 lttng_ust_unlock_fd_tracker();
1604 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1605 prev_connect_failed
= 1;
1608 * If we cannot find the sessiond daemon, don't delay
1609 * constructor execution.
1611 ret
= handle_register_failed(sock_info
);
1618 ret
= lttng_ust_add_fd_to_tracker(fd
);
1622 PERROR("close on sock_info->notify_socket");
1625 lttng_ust_unlock_fd_tracker();
1630 sock_info
->notify_socket
= ret
;
1631 lttng_ust_unlock_fd_tracker();
1635 * Unlock/relock ust lock because connect is blocking (with
1636 * timeout). Don't delay constructors on the ust lock for too
1643 timeout
= get_notify_sock_timeout();
1646 * Give at least 10ms to sessiond to reply to
1651 ret
= ustcomm_setsockopt_rcv_timeout(sock_info
->notify_socket
,
1654 WARN("Error setting socket receive timeout");
1656 ret
= ustcomm_setsockopt_snd_timeout(sock_info
->notify_socket
,
1659 WARN("Error setting socket send timeout");
1661 } else if (timeout
< -1) {
1662 WARN("Unsupported timeout value %ld", timeout
);
1665 ret
= register_to_sessiond(sock_info
->notify_socket
,
1666 USTCTL_SOCKET_NOTIFY
);
1668 ERR("Error registering to %s ust notify socket",
1670 prev_connect_failed
= 1;
1672 * If we cannot register to the sessiond daemon, don't
1673 * delay constructor execution.
1675 ret
= handle_register_failed(sock_info
);
1680 sock
= sock_info
->socket
;
1686 struct ustcomm_ust_msg lum
;
1688 len
= ustcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
1690 case 0: /* orderly shutdown */
1691 DBG("%s lttng-sessiond has performed an orderly shutdown", sock_info
->name
);
1696 * Either sessiond has shutdown or refused us by closing the socket.
1697 * In either case, we don't want to delay construction execution,
1698 * and we need to wait before retry.
1700 prev_connect_failed
= 1;
1702 * If we cannot register to the sessiond daemon, don't
1703 * delay constructor execution.
1705 ret
= handle_register_failed(sock_info
);
1710 print_cmd(lum
.cmd
, lum
.handle
);
1711 ret
= handle_message(sock_info
, sock
, &lum
);
1713 ERR("Error handling message for %s socket",
1716 * Close socket if protocol error is
1724 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1726 DBG("incorrect message size (%s socket): %zd", sock_info
->name
, len
);
1728 if (len
== -ECONNRESET
) {
1729 DBG("%s remote end closed connection", sock_info
->name
);
1740 /* Cleanup socket handles before trying to reconnect */
1741 lttng_ust_objd_table_owner_cleanup(sock_info
);
1743 goto restart
; /* try to reconnect */
1748 pthread_mutex_lock(&ust_exit_mutex
);
1749 sock_info
->thread_active
= 0;
1750 pthread_mutex_unlock(&ust_exit_mutex
);
1755 * Weak symbol to call when the ust malloc wrapper is not loaded.
1757 __attribute__((weak
))
1758 void lttng_ust_malloc_wrapper_init(void)
1763 * sessiond monitoring thread: monitor presence of global and per-user
1764 * sessiond by polling the application common named pipe.
1766 void __attribute__((constructor
)) lttng_ust_init(void)
1768 struct timespec constructor_timeout
;
1769 sigset_t sig_all_blocked
, orig_parent_mask
;
1770 pthread_attr_t thread_attr
;
1774 if (uatomic_xchg(&initialized
, 1) == 1)
1778 * Fixup interdependency between TLS fixup mutex (which happens
1779 * to be the dynamic linker mutex) and ust_lock, taken within
1782 lttng_ust_fixup_tls();
1784 lttng_ust_loaded
= 1;
1787 * We want precise control over the order in which we construct
1788 * our sub-libraries vs starting to receive commands from
1789 * sessiond (otherwise leading to errors when trying to create
1790 * sessiond before the init functions are completed).
1793 lttng_ust_getenv_init(); /* Needs init_usterr() to be completed. */
1795 lttng_ust_init_fd_tracker();
1796 lttng_ust_clock_init();
1797 lttng_ust_getcpu_init();
1798 lttng_ust_statedump_init();
1799 lttng_ring_buffer_metadata_client_init();
1800 lttng_ring_buffer_client_overwrite_init();
1801 lttng_ring_buffer_client_overwrite_rt_init();
1802 lttng_ring_buffer_client_discard_init();
1803 lttng_ring_buffer_client_discard_rt_init();
1804 lttng_perf_counter_init();
1806 * Invoke ust malloc wrapper init before starting other threads.
1808 lttng_ust_malloc_wrapper_init();
1810 timeout_mode
= get_constructor_timeout(&constructor_timeout
);
1812 get_allow_blocking();
1814 ret
= sem_init(&constructor_wait
, 0, 0);
1819 ret
= setup_global_apps();
1821 assert(global_apps
.allowed
== 0);
1822 DBG("global apps setup returned %d", ret
);
1825 ret
= setup_local_apps();
1827 assert(local_apps
.allowed
== 0);
1828 DBG("local apps setup returned %d", ret
);
1831 /* A new thread created by pthread_create inherits the signal mask
1832 * from the parent. To avoid any signal being received by the
1833 * listener thread, we block all signals temporarily in the parent,
1834 * while we create the listener thread.
1836 sigfillset(&sig_all_blocked
);
1837 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_parent_mask
);
1839 ERR("pthread_sigmask: %s", strerror(ret
));
1842 ret
= pthread_attr_init(&thread_attr
);
1844 ERR("pthread_attr_init: %s", strerror(ret
));
1846 ret
= pthread_attr_setdetachstate(&thread_attr
, PTHREAD_CREATE_DETACHED
);
1848 ERR("pthread_attr_setdetachstate: %s", strerror(ret
));
1851 if (global_apps
.allowed
) {
1852 pthread_mutex_lock(&ust_exit_mutex
);
1853 ret
= pthread_create(&global_apps
.ust_listener
, &thread_attr
,
1854 ust_listener_thread
, &global_apps
);
1856 ERR("pthread_create global: %s", strerror(ret
));
1858 global_apps
.thread_active
= 1;
1859 pthread_mutex_unlock(&ust_exit_mutex
);
1861 handle_register_done(&global_apps
);
1864 if (local_apps
.allowed
) {
1865 pthread_mutex_lock(&ust_exit_mutex
);
1866 ret
= pthread_create(&local_apps
.ust_listener
, &thread_attr
,
1867 ust_listener_thread
, &local_apps
);
1869 ERR("pthread_create local: %s", strerror(ret
));
1871 local_apps
.thread_active
= 1;
1872 pthread_mutex_unlock(&ust_exit_mutex
);
1874 handle_register_done(&local_apps
);
1876 ret
= pthread_attr_destroy(&thread_attr
);
1878 ERR("pthread_attr_destroy: %s", strerror(ret
));
1881 /* Restore original signal mask in parent */
1882 ret
= pthread_sigmask(SIG_SETMASK
, &orig_parent_mask
, NULL
);
1884 ERR("pthread_sigmask: %s", strerror(ret
));
1887 switch (timeout_mode
) {
1888 case 1: /* timeout wait */
1890 ret
= sem_timedwait(&constructor_wait
,
1891 &constructor_timeout
);
1892 } while (ret
< 0 && errno
== EINTR
);
1896 ERR("Timed out waiting for lttng-sessiond");
1899 PERROR("sem_timedwait");
1902 ERR("Unexpected error \"%s\" returned by sem_timedwait",
1907 case -1:/* wait forever */
1909 ret
= sem_wait(&constructor_wait
);
1910 } while (ret
< 0 && errno
== EINTR
);
1917 ERR("Unexpected error \"%s\" returned by sem_wait",
1922 case 0: /* no timeout */
1928 void lttng_ust_cleanup(int exiting
)
1930 cleanup_sock_info(&global_apps
, exiting
);
1931 cleanup_sock_info(&local_apps
, exiting
);
1932 local_apps
.allowed
= 0;
1933 global_apps
.allowed
= 0;
1935 * The teardown in this function all affect data structures
1936 * accessed under the UST lock by the listener thread. This
1937 * lock, along with the lttng_ust_comm_should_quit flag, ensure
1938 * that none of these threads are accessing this data at this
1941 lttng_ust_abi_exit();
1942 lttng_ust_events_exit();
1943 lttng_perf_counter_exit();
1944 lttng_ring_buffer_client_discard_rt_exit();
1945 lttng_ring_buffer_client_discard_exit();
1946 lttng_ring_buffer_client_overwrite_rt_exit();
1947 lttng_ring_buffer_client_overwrite_exit();
1948 lttng_ring_buffer_metadata_client_exit();
1949 lttng_ust_statedump_destroy();
1952 /* Reinitialize values for fork */
1953 sem_count
= sem_count_initial_value
;
1954 lttng_ust_comm_should_quit
= 0;
1959 void __attribute__((destructor
)) lttng_ust_exit(void)
1964 * Using pthread_cancel here because:
1965 * A) we don't want to hang application teardown.
1966 * B) the thread is not allocating any resource.
1970 * Require the communication thread to quit. Synchronize with
1971 * mutexes to ensure it is not in a mutex critical section when
1972 * pthread_cancel is later called.
1975 lttng_ust_comm_should_quit
= 1;
1978 pthread_mutex_lock(&ust_exit_mutex
);
1979 /* cancel threads */
1980 if (global_apps
.thread_active
) {
1981 ret
= pthread_cancel(global_apps
.ust_listener
);
1983 ERR("Error cancelling global ust listener thread: %s",
1986 global_apps
.thread_active
= 0;
1989 if (local_apps
.thread_active
) {
1990 ret
= pthread_cancel(local_apps
.ust_listener
);
1992 ERR("Error cancelling local ust listener thread: %s",
1995 local_apps
.thread_active
= 0;
1998 pthread_mutex_unlock(&ust_exit_mutex
);
2001 * Do NOT join threads: use of sys_futex makes it impossible to
2002 * join the threads without using async-cancel, but async-cancel
2003 * is delivered by a signal, which could hit the target thread
2004 * anywhere in its code path, including while the ust_lock() is
2005 * held, causing a deadlock for the other thread. Let the OS
2006 * cleanup the threads if there are stalled in a syscall.
2008 lttng_ust_cleanup(1);
2012 * We exclude the worker threads across fork and clone (except
2013 * CLONE_VM), because these system calls only keep the forking thread
2014 * running in the child. Therefore, we don't want to call fork or clone
2015 * in the middle of an tracepoint or ust tracing state modification.
2016 * Holding this mutex protects these structures across fork and clone.
2018 void ust_before_fork(sigset_t
*save_sigset
)
2021 * Disable signals. This is to avoid that the child intervenes
2022 * before it is properly setup for tracing. It is safer to
2023 * disable all signals, because then we know we are not breaking
2024 * anything by restoring the original mask.
2029 /* Fixup lttng-ust TLS. */
2030 lttng_ust_fixup_tls();
2032 if (URCU_TLS(lttng_ust_nest_count
))
2034 /* Disable signals */
2035 sigfillset(&all_sigs
);
2036 ret
= sigprocmask(SIG_BLOCK
, &all_sigs
, save_sigset
);
2038 PERROR("sigprocmask");
2041 pthread_mutex_lock(&ust_fork_mutex
);
2044 rcu_bp_before_fork();
2045 lttng_ust_lock_fd_tracker();
2048 static void ust_after_fork_common(sigset_t
*restore_sigset
)
2052 DBG("process %d", getpid());
2053 lttng_ust_unlock_fd_tracker();
2056 pthread_mutex_unlock(&ust_fork_mutex
);
2058 /* Restore signals */
2059 ret
= sigprocmask(SIG_SETMASK
, restore_sigset
, NULL
);
2061 PERROR("sigprocmask");
2065 void ust_after_fork_parent(sigset_t
*restore_sigset
)
2067 if (URCU_TLS(lttng_ust_nest_count
))
2069 DBG("process %d", getpid());
2070 rcu_bp_after_fork_parent();
2071 /* Release mutexes and reenable signals */
2072 ust_after_fork_common(restore_sigset
);
2076 * After fork, in the child, we need to cleanup all the leftover state,
2077 * except the worker thread which already magically disappeared thanks
2078 * to the weird Linux fork semantics. After tyding up, we call
2079 * lttng_ust_init() again to start over as a new PID.
2081 * This is meant for forks() that have tracing in the child between the
2082 * fork and following exec call (if there is any).
2084 void ust_after_fork_child(sigset_t
*restore_sigset
)
2086 if (URCU_TLS(lttng_ust_nest_count
))
2088 lttng_context_vpid_reset();
2089 lttng_context_vtid_reset();
2090 lttng_context_procname_reset();
2091 DBG("process %d", getpid());
2092 /* Release urcu mutexes */
2093 rcu_bp_after_fork_child();
2094 lttng_ust_cleanup(0);
2095 /* Release mutexes and reenable signals */
2096 ust_after_fork_common(restore_sigset
);
2100 void lttng_ust_sockinfo_session_enabled(void *owner
)
2102 struct sock_info
*sock_info
= owner
;
2103 sock_info
->statedump_pending
= 1;