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>
35 #include <semaphore.h>
40 #include <urcu/uatomic.h>
41 #include <urcu/futex.h>
42 #include <urcu/compiler.h>
44 #include <lttng/ust-events.h>
45 #include <lttng/ust-abi.h>
46 #include <lttng/ust.h>
47 #include <lttng/ust-error.h>
48 #include <lttng/ust-ctl.h>
49 #include <urcu/tls-compat.h>
52 #include <usterr-signal-safe.h>
54 #include "tracepoint-internal.h"
55 #include "lttng-tracer-core.h"
57 #include "../libringbuffer/rb-init.h"
58 #include "lttng-ust-statedump.h"
60 #include "../libringbuffer/getcpu.h"
63 /* Concatenate lttng ust shared library name with its major version number. */
64 #define LTTNG_UST_LIB_SO_NAME "liblttng-ust.so." __ust_stringify(CONFIG_LTTNG_UST_LIBRARY_VERSION_MAJOR)
67 * Has lttng ust comm constructor been called ?
69 static int initialized
;
72 * The ust_lock/ust_unlock lock is used as a communication thread mutex.
73 * Held when handling a command, also held by fork() to deal with
74 * removal of threads, and by exit path.
76 * The UST lock is the centralized mutex across UST tracing control and
79 * ust_exit_mutex must never nest in ust_mutex.
81 * ust_fork_mutex must never nest in ust_mutex.
83 * ust_mutex_nest is a per-thread nesting counter, allowing the perf
84 * counter lazy initialization called by events within the statedump,
85 * which traces while the ust_mutex is held.
87 * ust_lock nests within the dynamic loader lock (within glibc) because
88 * it is taken within the library constructor.
90 static pthread_mutex_t ust_mutex
= PTHREAD_MUTEX_INITIALIZER
;
92 /* Allow nesting the ust_mutex within the same thread. */
93 static DEFINE_URCU_TLS(int, ust_mutex_nest
);
96 * ust_exit_mutex protects thread_active variable wrt thread exit. It
97 * cannot be done by ust_mutex because pthread_cancel(), which takes an
98 * internal libc lock, cannot nest within ust_mutex.
100 * It never nests within a ust_mutex.
102 static pthread_mutex_t ust_exit_mutex
= PTHREAD_MUTEX_INITIALIZER
;
105 * ust_fork_mutex protects base address statedump tracing against forks. It
106 * prevents the dynamic loader lock to be taken (by base address statedump
107 * tracing) while a fork is happening, thus preventing deadlock issues with
108 * the dynamic loader lock.
110 static pthread_mutex_t ust_fork_mutex
= PTHREAD_MUTEX_INITIALIZER
;
112 /* Should the ust comm thread quit ? */
113 static int lttng_ust_comm_should_quit
;
116 * This variable can be tested by applications to check whether
117 * lttng-ust is loaded. They simply have to define their own
118 * "lttng_ust_loaded" weak symbol, and test it. It is set to 1 by the
119 * library constructor.
121 int lttng_ust_loaded
__attribute__((weak
));
124 * Return 0 on success, -1 if should quit.
125 * The lock is taken in both cases.
130 sigset_t sig_all_blocked
, orig_mask
;
133 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
135 ERR("pthread_setcancelstate: %s", strerror(ret
));
137 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
138 ERR("pthread_setcancelstate: unexpected oldstate");
140 sigfillset(&sig_all_blocked
);
141 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
143 ERR("pthread_sigmask: %s", strerror(ret
));
145 if (!URCU_TLS(ust_mutex_nest
)++)
146 pthread_mutex_lock(&ust_mutex
);
147 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
149 ERR("pthread_sigmask: %s", strerror(ret
));
151 if (lttng_ust_comm_should_quit
) {
159 * ust_lock_nocheck() can be used in constructors/destructors, because
160 * they are already nested within the dynamic loader lock, and therefore
161 * have exclusive access against execution of liblttng-ust destructor.
164 void ust_lock_nocheck(void)
166 sigset_t sig_all_blocked
, orig_mask
;
169 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
171 ERR("pthread_setcancelstate: %s", strerror(ret
));
173 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
174 ERR("pthread_setcancelstate: unexpected oldstate");
176 sigfillset(&sig_all_blocked
);
177 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
179 ERR("pthread_sigmask: %s", strerror(ret
));
181 if (!URCU_TLS(ust_mutex_nest
)++)
182 pthread_mutex_lock(&ust_mutex
);
183 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
185 ERR("pthread_sigmask: %s", strerror(ret
));
192 void ust_unlock(void)
194 sigset_t sig_all_blocked
, orig_mask
;
197 sigfillset(&sig_all_blocked
);
198 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
200 ERR("pthread_sigmask: %s", strerror(ret
));
202 if (!--URCU_TLS(ust_mutex_nest
))
203 pthread_mutex_unlock(&ust_mutex
);
204 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
206 ERR("pthread_sigmask: %s", strerror(ret
));
208 ret
= pthread_setcancelstate(PTHREAD_CANCEL_ENABLE
, &oldstate
);
210 ERR("pthread_setcancelstate: %s", strerror(ret
));
212 if (oldstate
!= PTHREAD_CANCEL_DISABLE
) {
213 ERR("pthread_setcancelstate: unexpected oldstate");
218 * Wait for either of these before continuing to the main
220 * - the register_done message from sessiond daemon
221 * (will let the sessiond daemon enable sessions before main
223 * - sessiond daemon is not reachable.
224 * - timeout (ensuring applications are resilient to session
227 static sem_t constructor_wait
;
229 * Doing this for both the global and local sessiond.
231 static int sem_count
= { 2 };
234 * Counting nesting within lttng-ust. Used to ensure that calling fork()
235 * from liblttng-ust does not execute the pre/post fork handlers.
237 static DEFINE_URCU_TLS(int, lttng_ust_nest_count
);
240 * Info about socket and associated listener thread.
244 pthread_t ust_listener
; /* listener thread */
246 int constructor_sem_posted
;
251 char sock_path
[PATH_MAX
];
255 char wait_shm_path
[PATH_MAX
];
257 /* Keep track of lazy state dump not performed yet. */
258 int statedump_pending
;
261 /* Socket from app (connect) to session daemon (listen) for communication */
262 struct sock_info global_apps
= {
270 .sock_path
= LTTNG_DEFAULT_RUNDIR
"/" LTTNG_UST_SOCK_FILENAME
,
274 .wait_shm_path
= "/" LTTNG_UST_WAIT_FILENAME
,
276 .statedump_pending
= 0,
279 /* TODO: allow global_apps_sock_path override */
281 struct sock_info local_apps
= {
285 .allowed
= 0, /* Check setuid bit first */
291 .statedump_pending
= 0,
294 static int wait_poll_fallback
;
296 static const char *cmd_name_mapping
[] = {
297 [ LTTNG_UST_RELEASE
] = "Release",
298 [ LTTNG_UST_SESSION
] = "Create Session",
299 [ LTTNG_UST_TRACER_VERSION
] = "Get Tracer Version",
301 [ LTTNG_UST_TRACEPOINT_LIST
] = "Create Tracepoint List",
302 [ LTTNG_UST_WAIT_QUIESCENT
] = "Wait for Quiescent State",
303 [ LTTNG_UST_REGISTER_DONE
] = "Registration Done",
304 [ LTTNG_UST_TRACEPOINT_FIELD_LIST
] = "Create Tracepoint Field List",
306 /* Session FD commands */
307 [ LTTNG_UST_CHANNEL
] = "Create Channel",
308 [ LTTNG_UST_SESSION_START
] = "Start Session",
309 [ LTTNG_UST_SESSION_STOP
] = "Stop Session",
311 /* Channel FD commands */
312 [ LTTNG_UST_STREAM
] = "Create Stream",
313 [ LTTNG_UST_EVENT
] = "Create Event",
315 /* Event and Channel FD commands */
316 [ LTTNG_UST_CONTEXT
] = "Create Context",
317 [ LTTNG_UST_FLUSH_BUFFER
] = "Flush Buffer",
319 /* Event, Channel and Session commands */
320 [ LTTNG_UST_ENABLE
] = "Enable",
321 [ LTTNG_UST_DISABLE
] = "Disable",
323 /* Tracepoint list commands */
324 [ LTTNG_UST_TRACEPOINT_LIST_GET
] = "List Next Tracepoint",
325 [ LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
] = "List Next Tracepoint Field",
327 /* Event FD commands */
328 [ LTTNG_UST_FILTER
] = "Create Filter",
329 [ LTTNG_UST_EXCLUSION
] = "Add exclusions to event",
332 static const char *str_timeout
;
333 static int got_timeout_env
;
335 extern void lttng_ring_buffer_client_overwrite_init(void);
336 extern void lttng_ring_buffer_client_overwrite_rt_init(void);
337 extern void lttng_ring_buffer_client_discard_init(void);
338 extern void lttng_ring_buffer_client_discard_rt_init(void);
339 extern void lttng_ring_buffer_metadata_client_init(void);
340 extern void lttng_ring_buffer_client_overwrite_exit(void);
341 extern void lttng_ring_buffer_client_overwrite_rt_exit(void);
342 extern void lttng_ring_buffer_client_discard_exit(void);
343 extern void lttng_ring_buffer_client_discard_rt_exit(void);
344 extern void lttng_ring_buffer_metadata_client_exit(void);
346 static char *get_map_shm(struct sock_info
*sock_info
);
348 ssize_t
lttng_ust_read(int fd
, void *buf
, size_t len
)
351 size_t copied
= 0, to_copy
= len
;
354 ret
= read(fd
, buf
+ copied
, to_copy
);
359 } while ((ret
> 0 && to_copy
> 0)
360 || (ret
< 0 && errno
== EINTR
));
367 * Returns the HOME directory path. Caller MUST NOT free(3) the returned
371 const char *get_lttng_home_dir(void)
375 val
= (const char *) lttng_getenv("LTTNG_HOME");
379 return (const char *) lttng_getenv("HOME");
383 * Force a read (imply TLS fixup for dlopen) of TLS variables.
386 void lttng_fixup_nest_count_tls(void)
388 asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count
)));
392 void lttng_fixup_ust_mutex_nest_tls(void)
394 asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest
)));
401 void lttng_fixup_urcu_bp_tls(void)
407 void lttng_ust_fixup_tls(void)
409 lttng_fixup_urcu_bp_tls();
410 lttng_fixup_ringbuffer_tls();
411 lttng_fixup_vtid_tls();
412 lttng_fixup_nest_count_tls();
413 lttng_fixup_procname_tls();
414 lttng_fixup_ust_mutex_nest_tls();
415 lttng_ust_fixup_fd_tracker_tls();
418 int lttng_get_notify_socket(void *owner
)
420 struct sock_info
*info
= owner
;
422 return info
->notify_socket
;
426 void print_cmd(int cmd
, int handle
)
428 const char *cmd_name
= "Unknown";
430 if (cmd
>= 0 && cmd
< LTTNG_ARRAY_SIZE(cmd_name_mapping
)
431 && cmd_name_mapping
[cmd
]) {
432 cmd_name
= cmd_name_mapping
[cmd
];
434 DBG("Message Received \"%s\" (%d), Handle \"%s\" (%d)",
436 lttng_ust_obj_get_name(handle
), handle
);
440 int setup_global_apps(void)
443 assert(!global_apps
.wait_shm_mmap
);
445 global_apps
.wait_shm_mmap
= get_map_shm(&global_apps
);
446 if (!global_apps
.wait_shm_mmap
) {
447 WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
448 global_apps
.allowed
= 0;
453 global_apps
.allowed
= 1;
458 int setup_local_apps(void)
461 const char *home_dir
;
464 assert(!local_apps
.wait_shm_mmap
);
468 * Disallow per-user tracing for setuid binaries.
470 if (uid
!= geteuid()) {
471 assert(local_apps
.allowed
== 0);
475 home_dir
= get_lttng_home_dir();
477 WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
478 assert(local_apps
.allowed
== 0);
482 local_apps
.allowed
= 1;
483 snprintf(local_apps
.sock_path
, PATH_MAX
, "%s/%s/%s",
485 LTTNG_DEFAULT_HOME_RUNDIR
,
486 LTTNG_UST_SOCK_FILENAME
);
487 snprintf(local_apps
.wait_shm_path
, PATH_MAX
, "/%s-%u",
488 LTTNG_UST_WAIT_FILENAME
,
491 local_apps
.wait_shm_mmap
= get_map_shm(&local_apps
);
492 if (!local_apps
.wait_shm_mmap
) {
493 WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
494 local_apps
.allowed
= 0;
503 * Get socket timeout, in ms.
504 * -1: wait forever. 0: don't wait. >0: timeout, in ms.
507 long get_timeout(void)
509 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
511 if (!got_timeout_env
) {
512 str_timeout
= lttng_getenv("LTTNG_UST_REGISTER_TIMEOUT");
516 constructor_delay_ms
= strtol(str_timeout
, NULL
, 10);
517 /* All negative values are considered as "-1". */
518 if (constructor_delay_ms
< -1)
519 constructor_delay_ms
= -1;
520 return constructor_delay_ms
;
523 /* Timeout for notify socket send and recv. */
525 long get_notify_sock_timeout(void)
527 return get_timeout();
530 /* Timeout for connecting to cmd and notify sockets. */
532 long get_connect_sock_timeout(void)
534 return get_timeout();
538 * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
541 int get_constructor_timeout(struct timespec
*constructor_timeout
)
543 long constructor_delay_ms
;
546 constructor_delay_ms
= get_timeout();
548 switch (constructor_delay_ms
) {
549 case -1:/* fall-through */
551 return constructor_delay_ms
;
557 * If we are unable to find the current time, don't wait.
559 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
564 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
565 constructor_timeout
->tv_nsec
+=
566 (constructor_delay_ms
% 1000UL) * 1000000UL;
567 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
568 constructor_timeout
->tv_sec
++;
569 constructor_timeout
->tv_nsec
-= 1000000000UL;
571 /* Timeout wait (constructor_delay_ms). */
576 void get_allow_blocking(void)
578 const char *str_allow_blocking
=
579 lttng_getenv("LTTNG_UST_ALLOW_BLOCKING");
581 if (str_allow_blocking
) {
582 DBG("%s environment variable is set",
583 "LTTNG_UST_ALLOW_BLOCKING");
584 lttng_ust_ringbuffer_set_allow_blocking();
589 int register_to_sessiond(int socket
, enum ustctl_socket_type type
)
591 return ustcomm_send_reg_msg(socket
,
594 lttng_alignof(uint8_t) * CHAR_BIT
,
595 lttng_alignof(uint16_t) * CHAR_BIT
,
596 lttng_alignof(uint32_t) * CHAR_BIT
,
597 lttng_alignof(uint64_t) * CHAR_BIT
,
598 lttng_alignof(unsigned long) * CHAR_BIT
);
602 int send_reply(int sock
, struct ustcomm_ust_reply
*lur
)
606 len
= ustcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
609 DBG("message successfully sent");
612 if (len
== -ECONNRESET
) {
613 DBG("remote end closed connection");
618 DBG("incorrect message size: %zd", len
);
624 int handle_register_done(struct sock_info
*sock_info
)
628 if (sock_info
->constructor_sem_posted
)
630 sock_info
->constructor_sem_posted
= 1;
631 if (uatomic_read(&sem_count
) <= 0) {
634 ret
= uatomic_add_return(&sem_count
, -1);
636 ret
= sem_post(&constructor_wait
);
643 * Only execute pending statedump after the constructor semaphore has
644 * been posted by each listener thread. This means statedump will only
645 * be performed after the "registration done" command is received from
646 * each session daemon the application is connected to.
648 * This ensures we don't run into deadlock issues with the dynamic
649 * loader mutex, which is held while the constructor is called and
650 * waiting on the constructor semaphore. All operations requiring this
651 * dynamic loader lock need to be postponed using this mechanism.
654 void handle_pending_statedump(struct sock_info
*sock_info
)
656 int ctor_passed
= sock_info
->constructor_sem_posted
;
658 if (ctor_passed
&& sock_info
->statedump_pending
) {
659 sock_info
->statedump_pending
= 0;
660 pthread_mutex_lock(&ust_fork_mutex
);
661 lttng_handle_pending_statedump(sock_info
);
662 pthread_mutex_unlock(&ust_fork_mutex
);
667 int handle_message(struct sock_info
*sock_info
,
668 int sock
, struct ustcomm_ust_msg
*lum
)
671 const struct lttng_ust_objd_ops
*ops
;
672 struct ustcomm_ust_reply lur
;
674 char ctxstr
[LTTNG_UST_SYM_NAME_LEN
]; /* App context string. */
677 memset(&lur
, 0, sizeof(lur
));
680 ret
= -LTTNG_UST_ERR_EXITING
;
684 ops
= objd_ops(lum
->handle
);
691 case LTTNG_UST_REGISTER_DONE
:
692 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
693 ret
= handle_register_done(sock_info
);
697 case LTTNG_UST_RELEASE
:
698 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
701 ret
= lttng_ust_objd_unref(lum
->handle
, 1);
703 case LTTNG_UST_FILTER
:
705 /* Receive filter data */
706 struct lttng_ust_filter_bytecode_node
*bytecode
;
708 if (lum
->u
.filter
.data_size
> FILTER_BYTECODE_MAX_LEN
) {
709 ERR("Filter data size is too large: %u bytes",
710 lum
->u
.filter
.data_size
);
715 if (lum
->u
.filter
.reloc_offset
> lum
->u
.filter
.data_size
) {
716 ERR("Filter reloc offset %u is not within data",
717 lum
->u
.filter
.reloc_offset
);
722 bytecode
= zmalloc(sizeof(*bytecode
) + lum
->u
.filter
.data_size
);
727 len
= ustcomm_recv_unix_sock(sock
, bytecode
->bc
.data
,
728 lum
->u
.filter
.data_size
);
730 case 0: /* orderly shutdown */
735 if (len
== lum
->u
.filter
.data_size
) {
736 DBG("filter data received");
738 } else if (len
< 0) {
739 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
740 if (len
== -ECONNRESET
) {
741 ERR("%s remote end closed connection", sock_info
->name
);
750 DBG("incorrect filter data message size: %zd", len
);
756 bytecode
->bc
.len
= lum
->u
.filter
.data_size
;
757 bytecode
->bc
.reloc_offset
= lum
->u
.filter
.reloc_offset
;
758 bytecode
->bc
.seqnum
= lum
->u
.filter
.seqnum
;
760 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
761 (unsigned long) bytecode
,
766 /* don't free bytecode if everything went fine. */
773 case LTTNG_UST_EXCLUSION
:
775 /* Receive exclusion names */
776 struct lttng_ust_excluder_node
*node
;
779 count
= lum
->u
.exclusion
.count
;
781 /* There are no names to read */
785 node
= zmalloc(sizeof(*node
) +
786 count
* LTTNG_UST_SYM_NAME_LEN
);
791 node
->excluder
.count
= count
;
792 len
= ustcomm_recv_unix_sock(sock
, node
->excluder
.names
,
793 count
* LTTNG_UST_SYM_NAME_LEN
);
795 case 0: /* orderly shutdown */
800 if (len
== count
* LTTNG_UST_SYM_NAME_LEN
) {
801 DBG("Exclusion data received");
803 } else if (len
< 0) {
804 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
805 if (len
== -ECONNRESET
) {
806 ERR("%s remote end closed connection", sock_info
->name
);
815 DBG("Incorrect exclusion data message size: %zd", len
);
822 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
823 (unsigned long) node
,
828 /* Don't free exclusion data if everything went fine. */
835 case LTTNG_UST_CHANNEL
:
840 len
= ustcomm_recv_channel_from_sessiond(sock
,
841 &chan_data
, lum
->u
.channel
.len
,
844 case 0: /* orderly shutdown */
848 if (len
== lum
->u
.channel
.len
) {
849 DBG("channel data received");
851 } else if (len
< 0) {
852 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
853 if (len
== -ECONNRESET
) {
854 ERR("%s remote end closed connection", sock_info
->name
);
861 DBG("incorrect channel data message size: %zd", len
);
866 args
.channel
.chan_data
= chan_data
;
867 args
.channel
.wakeup_fd
= wakeup_fd
;
869 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
870 (unsigned long) &lum
->u
,
876 case LTTNG_UST_STREAM
:
878 uint64_t memory_map_size
;
880 /* Receive shm_fd, wakeup_fd */
881 ret
= ustcomm_recv_stream_from_sessiond(sock
,
884 &args
.stream
.wakeup_fd
);
888 lum
->u
.stream
.len
= memory_map_size
;
891 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
892 (unsigned long) &lum
->u
,
898 case LTTNG_UST_CONTEXT
:
899 switch (lum
->u
.context
.ctx
) {
900 case LTTNG_UST_CONTEXT_APP_CONTEXT
:
903 size_t ctxlen
, recvlen
;
905 ctxlen
= strlen("$app.") + lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1
906 + strlen(":") + lum
->u
.context
.u
.app_ctx
.ctx_name_len
;
907 if (ctxlen
>= LTTNG_UST_SYM_NAME_LEN
) {
908 ERR("Application context string length size is too large: %zu bytes",
913 strcpy(ctxstr
, "$app.");
914 p
= &ctxstr
[strlen("$app.")];
915 recvlen
= ctxlen
- strlen("$app.");
916 len
= ustcomm_recv_unix_sock(sock
, p
, recvlen
);
918 case 0: /* orderly shutdown */
922 if (len
== recvlen
) {
923 DBG("app context data received");
925 } else if (len
< 0) {
926 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
927 if (len
== -ECONNRESET
) {
928 ERR("%s remote end closed connection", sock_info
->name
);
935 DBG("incorrect app context data message size: %zd", len
);
940 /* Put : between provider and ctxname. */
941 p
[lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1] = ':';
942 args
.app_context
.ctxname
= ctxstr
;
949 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
950 (unsigned long) &lum
->u
,
958 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
959 (unsigned long) &lum
->u
,
966 lur
.handle
= lum
->handle
;
970 lur
.ret_code
= LTTNG_UST_OK
;
973 * Use -LTTNG_UST_ERR as wildcard for UST internal
974 * error that are not caused by the transport, except if
975 * we already have a more precise error message to
978 if (ret
> -LTTNG_UST_ERR
) {
979 /* Translate code to UST error. */
982 lur
.ret_code
= -LTTNG_UST_ERR_EXIST
;
985 lur
.ret_code
= -LTTNG_UST_ERR_INVAL
;
988 lur
.ret_code
= -LTTNG_UST_ERR_NOENT
;
991 lur
.ret_code
= -LTTNG_UST_ERR_PERM
;
994 lur
.ret_code
= -LTTNG_UST_ERR_NOSYS
;
997 lur
.ret_code
= -LTTNG_UST_ERR
;
1006 case LTTNG_UST_TRACER_VERSION
:
1007 lur
.u
.version
= lum
->u
.version
;
1009 case LTTNG_UST_TRACEPOINT_LIST_GET
:
1010 memcpy(&lur
.u
.tracepoint
, &lum
->u
.tracepoint
, sizeof(lur
.u
.tracepoint
));
1014 DBG("Return value: %d", lur
.ret_val
);
1019 * Performed delayed statedump operations outside of the UST
1020 * lock. We need to take the dynamic loader lock before we take
1021 * the UST lock internally within handle_pending_statedump().
1023 handle_pending_statedump(sock_info
);
1026 ret
= -LTTNG_UST_ERR_EXITING
;
1030 ret
= send_reply(sock
, &lur
);
1032 DBG("error sending reply");
1037 * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field
1040 if (lur
.ret_code
== LTTNG_UST_OK
) {
1042 case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
:
1043 len
= ustcomm_send_unix_sock(sock
,
1044 &args
.field_list
.entry
,
1045 sizeof(args
.field_list
.entry
));
1050 if (len
!= sizeof(args
.field_list
.entry
)) {
1064 void cleanup_sock_info(struct sock_info
*sock_info
, int exiting
)
1068 if (sock_info
->root_handle
!= -1) {
1069 ret
= lttng_ust_objd_unref(sock_info
->root_handle
, 1);
1071 ERR("Error unref root handle");
1073 sock_info
->root_handle
= -1;
1075 sock_info
->constructor_sem_posted
= 0;
1078 * wait_shm_mmap, socket and notify socket are used by listener
1079 * threads outside of the ust lock, so we cannot tear them down
1080 * ourselves, because we cannot join on these threads. Leave
1081 * responsibility of cleaning up these resources to the OS
1087 if (sock_info
->socket
!= -1) {
1088 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1090 ERR("Error closing ust cmd socket");
1092 sock_info
->socket
= -1;
1094 if (sock_info
->notify_socket
!= -1) {
1095 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1097 ERR("Error closing ust notify socket");
1099 sock_info
->notify_socket
= -1;
1101 if (sock_info
->wait_shm_mmap
) {
1104 page_size
= sysconf(_SC_PAGE_SIZE
);
1105 if (page_size
<= 0) {
1109 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1111 ret
= munmap(sock_info
->wait_shm_mmap
, page_size
);
1113 ERR("Error unmapping wait shm");
1116 sock_info
->wait_shm_mmap
= NULL
;
1121 * Using fork to set umask in the child process (not multi-thread safe).
1122 * We deal with the shm_open vs ftruncate race (happening when the
1123 * sessiond owns the shm and does not let everybody modify it, to ensure
1124 * safety against shm_unlink) by simply letting the mmap fail and
1125 * retrying after a few seconds.
1126 * For global shm, everybody has rw access to it until the sessiond
1130 int get_wait_shm(struct sock_info
*sock_info
, size_t mmap_size
)
1132 int wait_shm_fd
, ret
;
1136 * Try to open read-only.
1138 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1139 if (wait_shm_fd
>= 0) {
1142 size_t bytes_read
= 0;
1145 * Try to read the fd. If unable to do so, try opening
1149 len
= read(wait_shm_fd
,
1150 &((char *) &tmp_read
)[bytes_read
],
1151 sizeof(tmp_read
) - bytes_read
);
1155 } while ((len
< 0 && errno
== EINTR
)
1156 || (len
> 0 && bytes_read
< sizeof(tmp_read
)));
1157 if (bytes_read
!= sizeof(tmp_read
)) {
1158 ret
= close(wait_shm_fd
);
1160 ERR("close wait_shm_fd");
1165 } else if (wait_shm_fd
< 0 && errno
!= ENOENT
) {
1167 * Real-only open did not work, and it's not because the
1168 * entry was not present. It's a failure that prohibits
1171 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1177 * If the open failed because the file did not exist, or because
1178 * the file was not truncated yet, try creating it ourself.
1180 URCU_TLS(lttng_ust_nest_count
)++;
1182 URCU_TLS(lttng_ust_nest_count
)--;
1187 * Parent: wait for child to return, in which case the
1188 * shared memory map will have been created.
1190 pid
= wait(&status
);
1191 if (pid
< 0 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0) {
1196 * Try to open read-only again after creation.
1198 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1199 if (wait_shm_fd
< 0) {
1201 * Real-only open did not work. It's a failure
1202 * that prohibits using shm.
1204 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1208 } else if (pid
== 0) {
1212 create_mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
;
1213 if (sock_info
->global
)
1214 create_mode
|= S_IROTH
| S_IWGRP
| S_IWOTH
;
1216 * We're alone in a child process, so we can modify the
1217 * process-wide umask.
1219 umask(~create_mode
);
1221 * Try creating shm (or get rw access).
1222 * We don't do an exclusive open, because we allow other
1223 * processes to create+ftruncate it concurrently.
1225 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
,
1226 O_RDWR
| O_CREAT
, create_mode
);
1227 if (wait_shm_fd
>= 0) {
1228 ret
= ftruncate(wait_shm_fd
, mmap_size
);
1230 PERROR("ftruncate");
1231 _exit(EXIT_FAILURE
);
1233 _exit(EXIT_SUCCESS
);
1236 * For local shm, we need to have rw access to accept
1237 * opening it: this means the local sessiond will be
1238 * able to wake us up. For global shm, we open it even
1239 * if rw access is not granted, because the root.root
1240 * sessiond will be able to override all rights and wake
1243 if (!sock_info
->global
&& errno
!= EACCES
) {
1244 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1245 _exit(EXIT_FAILURE
);
1248 * The shm exists, but we cannot open it RW. Report
1251 _exit(EXIT_SUCCESS
);
1256 if (wait_shm_fd
>= 0 && !sock_info
->global
) {
1257 struct stat statbuf
;
1260 * Ensure that our user is the owner of the shm file for
1261 * local shm. If we do not own the file, it means our
1262 * sessiond will not have access to wake us up (there is
1263 * probably a rogue process trying to fake our
1264 * sessiond). Fallback to polling method in this case.
1266 ret
= fstat(wait_shm_fd
, &statbuf
);
1271 if (statbuf
.st_uid
!= getuid())
1277 ret
= close(wait_shm_fd
);
1279 PERROR("Error closing fd");
1285 char *get_map_shm(struct sock_info
*sock_info
)
1288 int wait_shm_fd
, ret
;
1289 char *wait_shm_mmap
;
1291 page_size
= sysconf(_SC_PAGE_SIZE
);
1292 if (page_size
<= 0) {
1296 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1300 lttng_ust_lock_fd_tracker();
1301 wait_shm_fd
= get_wait_shm(sock_info
, page_size
);
1302 if (wait_shm_fd
< 0) {
1303 lttng_ust_unlock_fd_tracker();
1307 ret
= lttng_ust_add_fd_to_tracker(wait_shm_fd
);
1309 ret
= close(wait_shm_fd
);
1311 PERROR("Error closing fd");
1313 lttng_ust_unlock_fd_tracker();
1318 lttng_ust_unlock_fd_tracker();
1320 wait_shm_mmap
= mmap(NULL
, page_size
, PROT_READ
,
1321 MAP_SHARED
, wait_shm_fd
, 0);
1323 /* close shm fd immediately after taking the mmap reference */
1324 lttng_ust_lock_fd_tracker();
1325 ret
= close(wait_shm_fd
);
1327 lttng_ust_delete_fd_from_tracker(wait_shm_fd
);
1329 PERROR("Error closing fd");
1331 lttng_ust_unlock_fd_tracker();
1333 if (wait_shm_mmap
== MAP_FAILED
) {
1334 DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
1337 return wait_shm_mmap
;
1344 void wait_for_sessiond(struct sock_info
*sock_info
)
1346 /* Use ust_lock to check if we should quit. */
1350 if (wait_poll_fallback
) {
1355 assert(sock_info
->wait_shm_mmap
);
1357 DBG("Waiting for %s apps sessiond", sock_info
->name
);
1358 /* Wait for futex wakeup */
1359 if (uatomic_read((int32_t *) sock_info
->wait_shm_mmap
))
1362 while (futex_async((int32_t *) sock_info
->wait_shm_mmap
,
1363 FUTEX_WAIT
, 0, NULL
, NULL
, 0)) {
1366 /* Value already changed. */
1369 /* Retry if interrupted by signal. */
1370 break; /* Get out of switch. */
1372 wait_poll_fallback
= 1;
1374 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
1375 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
1376 "Please upgrade your kernel "
1377 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
1378 "mainline). LTTng-UST will use polling mode fallback.");
1397 * This thread does not allocate any resource, except within
1398 * handle_message, within mutex protection. This mutex protects against
1400 * The other moment it allocates resources is at socket connection, which
1401 * is also protected by the mutex.
1404 void *ust_listener_thread(void *arg
)
1406 struct sock_info
*sock_info
= arg
;
1407 int sock
, ret
, prev_connect_failed
= 0, has_waited
= 0, fd
;
1410 lttng_ust_fixup_tls();
1412 * If available, add '-ust' to the end of this thread's
1415 ret
= lttng_ust_setustprocname();
1417 ERR("Unable to set UST process name");
1420 /* Restart trying to connect to the session daemon */
1422 if (prev_connect_failed
) {
1423 /* Wait for sessiond availability with pipe */
1424 wait_for_sessiond(sock_info
);
1428 * Sleep for 5 seconds before retrying after a
1429 * sequence of failure / wait / failure. This
1430 * deals with a killed or broken session daemon.
1436 prev_connect_failed
= 0;
1443 if (sock_info
->socket
!= -1) {
1444 /* FD tracker is updated by ustcomm_close_unix_sock() */
1445 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1447 ERR("Error closing %s ust cmd socket",
1450 sock_info
->socket
= -1;
1452 if (sock_info
->notify_socket
!= -1) {
1453 /* FD tracker is updated by ustcomm_close_unix_sock() */
1454 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1456 ERR("Error closing %s ust notify socket",
1459 sock_info
->notify_socket
= -1;
1464 * Register. We need to perform both connect and sending
1465 * registration message before doing the next connect otherwise
1466 * we may reach unix socket connect queue max limits and block
1467 * on the 2nd connect while the session daemon is awaiting the
1468 * first connect registration message.
1470 /* Connect cmd socket */
1471 lttng_ust_lock_fd_tracker();
1472 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1473 get_connect_sock_timeout());
1475 lttng_ust_unlock_fd_tracker();
1476 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1477 prev_connect_failed
= 1;
1480 * If we cannot find the sessiond daemon, don't delay
1481 * constructor execution.
1483 ret
= handle_register_done(sock_info
);
1489 ret
= lttng_ust_add_fd_to_tracker(fd
);
1493 PERROR("close on sock_info->socket");
1496 lttng_ust_unlock_fd_tracker();
1501 sock_info
->socket
= ret
;
1502 lttng_ust_unlock_fd_tracker();
1506 * Unlock/relock ust lock because connect is blocking (with
1507 * timeout). Don't delay constructors on the ust lock for too
1515 * Create only one root handle per listener thread for the whole
1516 * process lifetime, so we ensure we get ID which is statically
1517 * assigned to the root handle.
1519 if (sock_info
->root_handle
== -1) {
1520 ret
= lttng_abi_create_root_handle();
1522 ERR("Error creating root handle");
1525 sock_info
->root_handle
= ret
;
1528 ret
= register_to_sessiond(sock_info
->socket
, USTCTL_SOCKET_CMD
);
1530 ERR("Error registering to %s ust cmd socket",
1532 prev_connect_failed
= 1;
1534 * If we cannot register to the sessiond daemon, don't
1535 * delay constructor execution.
1537 ret
= handle_register_done(sock_info
);
1545 * Unlock/relock ust lock because connect is blocking (with
1546 * timeout). Don't delay constructors on the ust lock for too
1553 /* Connect notify socket */
1554 lttng_ust_lock_fd_tracker();
1555 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1556 get_connect_sock_timeout());
1558 lttng_ust_unlock_fd_tracker();
1559 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1560 prev_connect_failed
= 1;
1563 * If we cannot find the sessiond daemon, don't delay
1564 * constructor execution.
1566 ret
= handle_register_done(sock_info
);
1573 ret
= lttng_ust_add_fd_to_tracker(fd
);
1577 PERROR("close on sock_info->notify_socket");
1580 lttng_ust_unlock_fd_tracker();
1585 sock_info
->notify_socket
= ret
;
1586 lttng_ust_unlock_fd_tracker();
1590 * Unlock/relock ust lock because connect is blocking (with
1591 * timeout). Don't delay constructors on the ust lock for too
1598 timeout
= get_notify_sock_timeout();
1601 * Give at least 10ms to sessiond to reply to
1606 ret
= ustcomm_setsockopt_rcv_timeout(sock_info
->notify_socket
,
1609 WARN("Error setting socket receive timeout");
1611 ret
= ustcomm_setsockopt_snd_timeout(sock_info
->notify_socket
,
1614 WARN("Error setting socket send timeout");
1616 } else if (timeout
< -1) {
1617 WARN("Unsupported timeout value %ld", timeout
);
1620 ret
= register_to_sessiond(sock_info
->notify_socket
,
1621 USTCTL_SOCKET_NOTIFY
);
1623 ERR("Error registering to %s ust notify socket",
1625 prev_connect_failed
= 1;
1627 * If we cannot register to the sessiond daemon, don't
1628 * delay constructor execution.
1630 ret
= handle_register_done(sock_info
);
1635 sock
= sock_info
->socket
;
1641 struct ustcomm_ust_msg lum
;
1643 len
= ustcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
1645 case 0: /* orderly shutdown */
1646 DBG("%s lttng-sessiond has performed an orderly shutdown", sock_info
->name
);
1651 * Either sessiond has shutdown or refused us by closing the socket.
1652 * In either case, we don't want to delay construction execution,
1653 * and we need to wait before retry.
1655 prev_connect_failed
= 1;
1657 * If we cannot register to the sessiond daemon, don't
1658 * delay constructor execution.
1660 ret
= handle_register_done(sock_info
);
1665 print_cmd(lum
.cmd
, lum
.handle
);
1666 ret
= handle_message(sock_info
, sock
, &lum
);
1668 ERR("Error handling message for %s socket",
1671 * Close socket if protocol error is
1679 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1681 DBG("incorrect message size (%s socket): %zd", sock_info
->name
, len
);
1683 if (len
== -ECONNRESET
) {
1684 DBG("%s remote end closed connection", sock_info
->name
);
1695 /* Cleanup socket handles before trying to reconnect */
1696 lttng_ust_objd_table_owner_cleanup(sock_info
);
1698 goto restart
; /* try to reconnect */
1703 pthread_mutex_lock(&ust_exit_mutex
);
1704 sock_info
->thread_active
= 0;
1705 pthread_mutex_unlock(&ust_exit_mutex
);
1710 * Weak symbol to call when the ust malloc wrapper is not loaded.
1712 __attribute__((weak
))
1713 void lttng_ust_malloc_wrapper_init(void)
1718 * sessiond monitoring thread: monitor presence of global and per-user
1719 * sessiond by polling the application common named pipe.
1721 void __attribute__((constructor
)) lttng_ust_init(void)
1723 struct timespec constructor_timeout
;
1724 sigset_t sig_all_blocked
, orig_parent_mask
;
1725 pthread_attr_t thread_attr
;
1730 if (uatomic_xchg(&initialized
, 1) == 1)
1734 * Fixup interdependency between TLS fixup mutex (which happens
1735 * to be the dynamic linker mutex) and ust_lock, taken within
1738 lttng_ust_fixup_tls();
1740 lttng_ust_loaded
= 1;
1743 * We need to ensure that the liblttng-ust library is not unloaded to avoid
1744 * the unloading of code used by the ust_listener_threads as we can not
1745 * reliably know when they exited. To do that, manually load
1746 * liblttng-ust.so to increment the dynamic loader's internal refcount for
1747 * this library so it never becomes zero, thus never gets unloaded from the
1748 * address space of the process. Since we are already running in the
1749 * constructor of the LTTNG_UST_LIB_SO_NAME library, calling dlopen will
1750 * simply increment the refcount and no additionnal work is needed by the
1751 * dynamic loader as the shared library is already loaded in the address
1752 * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
1753 * unloading of the UST library if its refcount becomes zero (which should
1754 * never happen). Do the return value check but discard the handle at the
1755 * end of the function as it's not needed.
1757 handle
= dlopen(LTTNG_UST_LIB_SO_NAME
, RTLD_LAZY
| RTLD_NODELETE
);
1759 ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SO_NAME
);
1763 * We want precise control over the order in which we construct
1764 * our sub-libraries vs starting to receive commands from
1765 * sessiond (otherwise leading to errors when trying to create
1766 * sessiond before the init functions are completed).
1769 lttng_ust_getenv_init(); /* Needs init_usterr() to be completed. */
1771 lttng_ust_init_fd_tracker();
1772 lttng_ust_clock_init();
1773 lttng_ust_getcpu_init();
1774 lttng_ust_statedump_init();
1775 lttng_ring_buffer_metadata_client_init();
1776 lttng_ring_buffer_client_overwrite_init();
1777 lttng_ring_buffer_client_overwrite_rt_init();
1778 lttng_ring_buffer_client_discard_init();
1779 lttng_ring_buffer_client_discard_rt_init();
1780 lttng_perf_counter_init();
1782 * Invoke ust malloc wrapper init before starting other threads.
1784 lttng_ust_malloc_wrapper_init();
1786 timeout_mode
= get_constructor_timeout(&constructor_timeout
);
1788 get_allow_blocking();
1790 ret
= sem_init(&constructor_wait
, 0, 0);
1795 ret
= setup_global_apps();
1797 assert(global_apps
.allowed
== 0);
1798 DBG("global apps setup returned %d", ret
);
1801 ret
= setup_local_apps();
1803 assert(local_apps
.allowed
== 0);
1804 DBG("local apps setup returned %d", ret
);
1807 /* A new thread created by pthread_create inherits the signal mask
1808 * from the parent. To avoid any signal being received by the
1809 * listener thread, we block all signals temporarily in the parent,
1810 * while we create the listener thread.
1812 sigfillset(&sig_all_blocked
);
1813 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_parent_mask
);
1815 ERR("pthread_sigmask: %s", strerror(ret
));
1818 ret
= pthread_attr_init(&thread_attr
);
1820 ERR("pthread_attr_init: %s", strerror(ret
));
1822 ret
= pthread_attr_setdetachstate(&thread_attr
, PTHREAD_CREATE_DETACHED
);
1824 ERR("pthread_attr_setdetachstate: %s", strerror(ret
));
1827 if (global_apps
.allowed
) {
1828 pthread_mutex_lock(&ust_exit_mutex
);
1829 ret
= pthread_create(&global_apps
.ust_listener
, &thread_attr
,
1830 ust_listener_thread
, &global_apps
);
1832 ERR("pthread_create global: %s", strerror(ret
));
1834 global_apps
.thread_active
= 1;
1835 pthread_mutex_unlock(&ust_exit_mutex
);
1837 handle_register_done(&global_apps
);
1840 if (local_apps
.allowed
) {
1841 pthread_mutex_lock(&ust_exit_mutex
);
1842 ret
= pthread_create(&local_apps
.ust_listener
, &thread_attr
,
1843 ust_listener_thread
, &local_apps
);
1845 ERR("pthread_create local: %s", strerror(ret
));
1847 local_apps
.thread_active
= 1;
1848 pthread_mutex_unlock(&ust_exit_mutex
);
1850 handle_register_done(&local_apps
);
1852 ret
= pthread_attr_destroy(&thread_attr
);
1854 ERR("pthread_attr_destroy: %s", strerror(ret
));
1857 /* Restore original signal mask in parent */
1858 ret
= pthread_sigmask(SIG_SETMASK
, &orig_parent_mask
, NULL
);
1860 ERR("pthread_sigmask: %s", strerror(ret
));
1863 switch (timeout_mode
) {
1864 case 1: /* timeout wait */
1866 ret
= sem_timedwait(&constructor_wait
,
1867 &constructor_timeout
);
1868 } while (ret
< 0 && errno
== EINTR
);
1872 ERR("Timed out waiting for lttng-sessiond");
1875 PERROR("sem_timedwait");
1878 ERR("Unexpected error \"%s\" returned by sem_timedwait",
1883 case -1:/* wait forever */
1885 ret
= sem_wait(&constructor_wait
);
1886 } while (ret
< 0 && errno
== EINTR
);
1893 ERR("Unexpected error \"%s\" returned by sem_wait",
1898 case 0: /* no timeout */
1904 void lttng_ust_cleanup(int exiting
)
1906 cleanup_sock_info(&global_apps
, exiting
);
1907 cleanup_sock_info(&local_apps
, exiting
);
1908 local_apps
.allowed
= 0;
1909 global_apps
.allowed
= 0;
1911 * The teardown in this function all affect data structures
1912 * accessed under the UST lock by the listener thread. This
1913 * lock, along with the lttng_ust_comm_should_quit flag, ensure
1914 * that none of these threads are accessing this data at this
1917 lttng_ust_abi_exit();
1918 lttng_ust_events_exit();
1919 lttng_perf_counter_exit();
1920 lttng_ring_buffer_client_discard_rt_exit();
1921 lttng_ring_buffer_client_discard_exit();
1922 lttng_ring_buffer_client_overwrite_rt_exit();
1923 lttng_ring_buffer_client_overwrite_exit();
1924 lttng_ring_buffer_metadata_client_exit();
1925 lttng_ust_statedump_destroy();
1928 /* Reinitialize values for fork */
1930 lttng_ust_comm_should_quit
= 0;
1935 void __attribute__((destructor
)) lttng_ust_exit(void)
1940 * Using pthread_cancel here because:
1941 * A) we don't want to hang application teardown.
1942 * B) the thread is not allocating any resource.
1946 * Require the communication thread to quit. Synchronize with
1947 * mutexes to ensure it is not in a mutex critical section when
1948 * pthread_cancel is later called.
1951 lttng_ust_comm_should_quit
= 1;
1954 pthread_mutex_lock(&ust_exit_mutex
);
1955 /* cancel threads */
1956 if (global_apps
.thread_active
) {
1957 ret
= pthread_cancel(global_apps
.ust_listener
);
1959 ERR("Error cancelling global ust listener thread: %s",
1962 global_apps
.thread_active
= 0;
1965 if (local_apps
.thread_active
) {
1966 ret
= pthread_cancel(local_apps
.ust_listener
);
1968 ERR("Error cancelling local ust listener thread: %s",
1971 local_apps
.thread_active
= 0;
1974 pthread_mutex_unlock(&ust_exit_mutex
);
1977 * Do NOT join threads: use of sys_futex makes it impossible to
1978 * join the threads without using async-cancel, but async-cancel
1979 * is delivered by a signal, which could hit the target thread
1980 * anywhere in its code path, including while the ust_lock() is
1981 * held, causing a deadlock for the other thread. Let the OS
1982 * cleanup the threads if there are stalled in a syscall.
1984 lttng_ust_cleanup(1);
1988 * We exclude the worker threads across fork and clone (except
1989 * CLONE_VM), because these system calls only keep the forking thread
1990 * running in the child. Therefore, we don't want to call fork or clone
1991 * in the middle of an tracepoint or ust tracing state modification.
1992 * Holding this mutex protects these structures across fork and clone.
1994 void ust_before_fork(sigset_t
*save_sigset
)
1997 * Disable signals. This is to avoid that the child intervenes
1998 * before it is properly setup for tracing. It is safer to
1999 * disable all signals, because then we know we are not breaking
2000 * anything by restoring the original mask.
2005 /* Fixup lttng-ust TLS. */
2006 lttng_ust_fixup_tls();
2008 if (URCU_TLS(lttng_ust_nest_count
))
2010 /* Disable signals */
2011 sigfillset(&all_sigs
);
2012 ret
= sigprocmask(SIG_BLOCK
, &all_sigs
, save_sigset
);
2014 PERROR("sigprocmask");
2017 pthread_mutex_lock(&ust_fork_mutex
);
2020 urcu_bp_before_fork();
2023 static void ust_after_fork_common(sigset_t
*restore_sigset
)
2027 DBG("process %d", getpid());
2030 pthread_mutex_unlock(&ust_fork_mutex
);
2032 /* Restore signals */
2033 ret
= sigprocmask(SIG_SETMASK
, restore_sigset
, NULL
);
2035 PERROR("sigprocmask");
2039 void ust_after_fork_parent(sigset_t
*restore_sigset
)
2041 if (URCU_TLS(lttng_ust_nest_count
))
2043 DBG("process %d", getpid());
2044 urcu_bp_after_fork_parent();
2045 /* Release mutexes and reenable signals */
2046 ust_after_fork_common(restore_sigset
);
2050 * After fork, in the child, we need to cleanup all the leftover state,
2051 * except the worker thread which already magically disappeared thanks
2052 * to the weird Linux fork semantics. After tyding up, we call
2053 * lttng_ust_init() again to start over as a new PID.
2055 * This is meant for forks() that have tracing in the child between the
2056 * fork and following exec call (if there is any).
2058 void ust_after_fork_child(sigset_t
*restore_sigset
)
2060 if (URCU_TLS(lttng_ust_nest_count
))
2062 lttng_context_vpid_reset();
2063 lttng_context_vtid_reset();
2064 lttng_context_procname_reset();
2065 DBG("process %d", getpid());
2066 /* Release urcu mutexes */
2067 urcu_bp_after_fork_child();
2068 lttng_ust_cleanup(0);
2069 /* Release mutexes and reenable signals */
2070 ust_after_fork_common(restore_sigset
);
2074 void lttng_ust_sockinfo_session_enabled(void *owner
)
2076 struct sock_info
*sock_info
= owner
;
2077 sock_info
->statedump_pending
= 1;