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
26 #include <sys/types.h>
27 #include <sys/socket.h>
30 #include <sys/types.h>
37 #include <semaphore.h>
42 #include <urcu/uatomic.h>
43 #include <urcu/futex.h>
44 #include <urcu/compiler.h>
46 #include <lttng/ust-events.h>
47 #include <lttng/ust-abi.h>
48 #include <lttng/ust.h>
49 #include <lttng/ust-error.h>
50 #include <lttng/ust-ctl.h>
51 #include <urcu/tls-compat.h>
54 #include <usterr-signal-safe.h>
56 #include "tracepoint-internal.h"
57 #include "lttng-tracer-core.h"
59 #include "../libringbuffer/rb-init.h"
60 #include "lttng-ust-statedump.h"
62 #include "../libringbuffer/getcpu.h"
64 #include "ust-events-internal.h"
66 /* Concatenate lttng ust shared library name with its major version number. */
67 #define LTTNG_UST_LIB_SO_NAME "liblttng-ust.so." __ust_stringify(CONFIG_LTTNG_UST_LIBRARY_VERSION_MAJOR)
70 * Has lttng ust comm constructor been called ?
72 static int initialized
;
75 * The ust_lock/ust_unlock lock is used as a communication thread mutex.
76 * Held when handling a command, also held by fork() to deal with
77 * removal of threads, and by exit path.
79 * The UST lock is the centralized mutex across UST tracing control and
82 * ust_exit_mutex must never nest in ust_mutex.
84 * ust_fork_mutex must never nest in ust_mutex.
86 * ust_mutex_nest is a per-thread nesting counter, allowing the perf
87 * counter lazy initialization called by events within the statedump,
88 * which traces while the ust_mutex is held.
90 * ust_lock nests within the dynamic loader lock (within glibc) because
91 * it is taken within the library constructor.
93 * The ust fd tracker lock nests within the ust_mutex.
95 static pthread_mutex_t ust_mutex
= PTHREAD_MUTEX_INITIALIZER
;
97 /* Allow nesting the ust_mutex within the same thread. */
98 static DEFINE_URCU_TLS(int, ust_mutex_nest
);
101 * ust_exit_mutex protects thread_active variable wrt thread exit. It
102 * cannot be done by ust_mutex because pthread_cancel(), which takes an
103 * internal libc lock, cannot nest within ust_mutex.
105 * It never nests within a ust_mutex.
107 static pthread_mutex_t ust_exit_mutex
= PTHREAD_MUTEX_INITIALIZER
;
110 * ust_fork_mutex protects base address statedump tracing against forks. It
111 * prevents the dynamic loader lock to be taken (by base address statedump
112 * tracing) while a fork is happening, thus preventing deadlock issues with
113 * the dynamic loader lock.
115 static pthread_mutex_t ust_fork_mutex
= PTHREAD_MUTEX_INITIALIZER
;
117 /* Should the ust comm thread quit ? */
118 static int lttng_ust_comm_should_quit
;
121 * This variable can be tested by applications to check whether
122 * lttng-ust is loaded. They simply have to define their own
123 * "lttng_ust_loaded" weak symbol, and test it. It is set to 1 by the
124 * library constructor.
126 int lttng_ust_loaded
__attribute__((weak
));
129 * Return 0 on success, -1 if should quit.
130 * The lock is taken in both cases.
135 sigset_t sig_all_blocked
, orig_mask
;
138 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
140 ERR("pthread_setcancelstate: %s", strerror(ret
));
142 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
143 ERR("pthread_setcancelstate: unexpected oldstate");
145 sigfillset(&sig_all_blocked
);
146 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
148 ERR("pthread_sigmask: %s", strerror(ret
));
150 if (!URCU_TLS(ust_mutex_nest
)++)
151 pthread_mutex_lock(&ust_mutex
);
152 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
154 ERR("pthread_sigmask: %s", strerror(ret
));
156 if (lttng_ust_comm_should_quit
) {
164 * ust_lock_nocheck() can be used in constructors/destructors, because
165 * they are already nested within the dynamic loader lock, and therefore
166 * have exclusive access against execution of liblttng-ust destructor.
169 void ust_lock_nocheck(void)
171 sigset_t sig_all_blocked
, orig_mask
;
174 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
176 ERR("pthread_setcancelstate: %s", strerror(ret
));
178 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
179 ERR("pthread_setcancelstate: unexpected oldstate");
181 sigfillset(&sig_all_blocked
);
182 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
184 ERR("pthread_sigmask: %s", strerror(ret
));
186 if (!URCU_TLS(ust_mutex_nest
)++)
187 pthread_mutex_lock(&ust_mutex
);
188 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
190 ERR("pthread_sigmask: %s", strerror(ret
));
197 void ust_unlock(void)
199 sigset_t sig_all_blocked
, orig_mask
;
202 sigfillset(&sig_all_blocked
);
203 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
205 ERR("pthread_sigmask: %s", strerror(ret
));
207 if (!--URCU_TLS(ust_mutex_nest
))
208 pthread_mutex_unlock(&ust_mutex
);
209 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
211 ERR("pthread_sigmask: %s", strerror(ret
));
213 ret
= pthread_setcancelstate(PTHREAD_CANCEL_ENABLE
, &oldstate
);
215 ERR("pthread_setcancelstate: %s", strerror(ret
));
217 if (oldstate
!= PTHREAD_CANCEL_DISABLE
) {
218 ERR("pthread_setcancelstate: unexpected oldstate");
223 * Wait for either of these before continuing to the main
225 * - the register_done message from sessiond daemon
226 * (will let the sessiond daemon enable sessions before main
228 * - sessiond daemon is not reachable.
229 * - timeout (ensuring applications are resilient to session
232 static sem_t constructor_wait
;
234 * Doing this for both the global and local sessiond.
237 sem_count_initial_value
= 4,
240 static int sem_count
= sem_count_initial_value
;
243 * Counting nesting within lttng-ust. Used to ensure that calling fork()
244 * from liblttng-ust does not execute the pre/post fork handlers.
246 static DEFINE_URCU_TLS(int, lttng_ust_nest_count
);
249 * Info about socket and associated listener thread.
253 pthread_t ust_listener
; /* listener thread */
255 int registration_done
;
260 char sock_path
[PATH_MAX
];
264 char wait_shm_path
[PATH_MAX
];
266 /* Keep track of lazy state dump not performed yet. */
267 int statedump_pending
;
268 int initial_statedump_done
;
269 /* Keep procname for statedump */
270 char procname
[LTTNG_UST_PROCNAME_LEN
];
273 /* Socket from app (connect) to session daemon (listen) for communication */
274 struct sock_info global_apps
= {
279 .registration_done
= 0,
283 .sock_path
= LTTNG_DEFAULT_RUNDIR
"/" LTTNG_UST_SOCK_FILENAME
,
287 .wait_shm_path
= "/" LTTNG_UST_WAIT_FILENAME
,
289 .statedump_pending
= 0,
290 .initial_statedump_done
= 0,
294 /* TODO: allow global_apps_sock_path override */
296 struct sock_info local_apps
= {
300 .registration_done
= 0,
301 .allowed
= 0, /* Check setuid bit first */
307 .statedump_pending
= 0,
308 .initial_statedump_done
= 0,
312 static int wait_poll_fallback
;
314 static const char *cmd_name_mapping
[] = {
315 [ LTTNG_UST_RELEASE
] = "Release",
316 [ LTTNG_UST_SESSION
] = "Create Session",
317 [ LTTNG_UST_TRACER_VERSION
] = "Get Tracer Version",
319 [ LTTNG_UST_TRACEPOINT_LIST
] = "Create Tracepoint List",
320 [ LTTNG_UST_WAIT_QUIESCENT
] = "Wait for Quiescent State",
321 [ LTTNG_UST_REGISTER_DONE
] = "Registration Done",
322 [ LTTNG_UST_TRACEPOINT_FIELD_LIST
] = "Create Tracepoint Field List",
324 [ LTTNG_UST_TRIGGER_GROUP_CREATE
] = "Create trigger group",
325 [ LTTNG_UST_TRIGGER_CREATE
] = "Create trigger",
327 /* Session FD commands */
328 [ LTTNG_UST_CHANNEL
] = "Create Channel",
329 [ LTTNG_UST_SESSION_START
] = "Start Session",
330 [ LTTNG_UST_SESSION_STOP
] = "Stop Session",
332 /* Channel FD commands */
333 [ LTTNG_UST_STREAM
] = "Create Stream",
334 [ LTTNG_UST_EVENT
] = "Create Event",
336 /* Event and Channel FD commands */
337 [ LTTNG_UST_CONTEXT
] = "Create Context",
338 [ LTTNG_UST_FLUSH_BUFFER
] = "Flush Buffer",
340 /* Event, Channel and Session commands */
341 [ LTTNG_UST_ENABLE
] = "Enable",
342 [ LTTNG_UST_DISABLE
] = "Disable",
344 /* Tracepoint list commands */
345 [ LTTNG_UST_TRACEPOINT_LIST_GET
] = "List Next Tracepoint",
346 [ LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
] = "List Next Tracepoint Field",
348 /* Event FD commands */
349 [ LTTNG_UST_FILTER
] = "Create Filter",
350 [ LTTNG_UST_EXCLUSION
] = "Add exclusions to event",
353 static const char *str_timeout
;
354 static int got_timeout_env
;
356 extern void lttng_ring_buffer_client_overwrite_init(void);
357 extern void lttng_ring_buffer_client_overwrite_rt_init(void);
358 extern void lttng_ring_buffer_client_discard_init(void);
359 extern void lttng_ring_buffer_client_discard_rt_init(void);
360 extern void lttng_ring_buffer_metadata_client_init(void);
361 extern void lttng_ring_buffer_client_overwrite_exit(void);
362 extern void lttng_ring_buffer_client_overwrite_rt_exit(void);
363 extern void lttng_ring_buffer_client_discard_exit(void);
364 extern void lttng_ring_buffer_client_discard_rt_exit(void);
365 extern void lttng_ring_buffer_metadata_client_exit(void);
367 static char *get_map_shm(struct sock_info
*sock_info
);
369 ssize_t
lttng_ust_read(int fd
, void *buf
, size_t len
)
372 size_t copied
= 0, to_copy
= len
;
375 ret
= read(fd
, buf
+ copied
, to_copy
);
380 } while ((ret
> 0 && to_copy
> 0)
381 || (ret
< 0 && errno
== EINTR
));
388 * Returns the HOME directory path. Caller MUST NOT free(3) the returned
392 const char *get_lttng_home_dir(void)
396 val
= (const char *) lttng_getenv("LTTNG_HOME");
400 return (const char *) lttng_getenv("HOME");
404 * Force a read (imply TLS fixup for dlopen) of TLS variables.
407 void lttng_fixup_nest_count_tls(void)
409 asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count
)));
413 void lttng_fixup_ust_mutex_nest_tls(void)
415 asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest
)));
422 void lttng_fixup_urcu_bp_tls(void)
428 void lttng_ust_fixup_tls(void)
430 lttng_fixup_urcu_bp_tls();
431 lttng_fixup_ringbuffer_tls();
432 lttng_fixup_vtid_tls();
433 lttng_fixup_nest_count_tls();
434 lttng_fixup_procname_tls();
435 lttng_fixup_ust_mutex_nest_tls();
436 lttng_ust_fixup_perf_counter_tls();
437 lttng_ust_fixup_fd_tracker_tls();
438 lttng_fixup_cgroup_ns_tls();
439 lttng_fixup_ipc_ns_tls();
440 lttng_fixup_net_ns_tls();
441 lttng_fixup_uts_ns_tls();
444 int lttng_get_notify_socket(void *owner
)
446 struct sock_info
*info
= owner
;
448 return info
->notify_socket
;
453 char* lttng_ust_sockinfo_get_procname(void *owner
)
455 struct sock_info
*info
= owner
;
457 return info
->procname
;
461 void print_cmd(int cmd
, int handle
)
463 const char *cmd_name
= "Unknown";
465 if (cmd
>= 0 && cmd
< LTTNG_ARRAY_SIZE(cmd_name_mapping
)
466 && cmd_name_mapping
[cmd
]) {
467 cmd_name
= cmd_name_mapping
[cmd
];
469 DBG("Message Received \"%s\" (%d), Handle \"%s\" (%d)",
471 lttng_ust_obj_get_name(handle
), handle
);
475 int setup_global_apps(void)
478 assert(!global_apps
.wait_shm_mmap
);
480 global_apps
.wait_shm_mmap
= get_map_shm(&global_apps
);
481 if (!global_apps
.wait_shm_mmap
) {
482 WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
483 global_apps
.allowed
= 0;
488 global_apps
.allowed
= 1;
489 lttng_ust_getprocname(global_apps
.procname
);
494 int setup_local_apps(void)
497 const char *home_dir
;
500 assert(!local_apps
.wait_shm_mmap
);
504 * Disallow per-user tracing for setuid binaries.
506 if (uid
!= geteuid()) {
507 assert(local_apps
.allowed
== 0);
511 home_dir
= get_lttng_home_dir();
513 WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
514 assert(local_apps
.allowed
== 0);
518 local_apps
.allowed
= 1;
519 snprintf(local_apps
.sock_path
, PATH_MAX
, "%s/%s/%s",
521 LTTNG_DEFAULT_HOME_RUNDIR
,
522 LTTNG_UST_SOCK_FILENAME
);
523 snprintf(local_apps
.wait_shm_path
, PATH_MAX
, "/%s-%u",
524 LTTNG_UST_WAIT_FILENAME
,
527 local_apps
.wait_shm_mmap
= get_map_shm(&local_apps
);
528 if (!local_apps
.wait_shm_mmap
) {
529 WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
530 local_apps
.allowed
= 0;
535 lttng_ust_getprocname(local_apps
.procname
);
541 * Get socket timeout, in ms.
542 * -1: wait forever. 0: don't wait. >0: timeout, in ms.
545 long get_timeout(void)
547 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
549 if (!got_timeout_env
) {
550 str_timeout
= lttng_getenv("LTTNG_UST_REGISTER_TIMEOUT");
554 constructor_delay_ms
= strtol(str_timeout
, NULL
, 10);
555 /* All negative values are considered as "-1". */
556 if (constructor_delay_ms
< -1)
557 constructor_delay_ms
= -1;
558 return constructor_delay_ms
;
561 /* Timeout for notify socket send and recv. */
563 long get_notify_sock_timeout(void)
565 return get_timeout();
568 /* Timeout for connecting to cmd and notify sockets. */
570 long get_connect_sock_timeout(void)
572 return get_timeout();
576 * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
579 int get_constructor_timeout(struct timespec
*constructor_timeout
)
581 long constructor_delay_ms
;
584 constructor_delay_ms
= get_timeout();
586 switch (constructor_delay_ms
) {
587 case -1:/* fall-through */
589 return constructor_delay_ms
;
595 * If we are unable to find the current time, don't wait.
597 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
602 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
603 constructor_timeout
->tv_nsec
+=
604 (constructor_delay_ms
% 1000UL) * 1000000UL;
605 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
606 constructor_timeout
->tv_sec
++;
607 constructor_timeout
->tv_nsec
-= 1000000000UL;
609 /* Timeout wait (constructor_delay_ms). */
614 void get_allow_blocking(void)
616 const char *str_allow_blocking
=
617 lttng_getenv("LTTNG_UST_ALLOW_BLOCKING");
619 if (str_allow_blocking
) {
620 DBG("%s environment variable is set",
621 "LTTNG_UST_ALLOW_BLOCKING");
622 lttng_ust_ringbuffer_set_allow_blocking();
627 int register_to_sessiond(int socket
, enum ustctl_socket_type type
)
629 return ustcomm_send_reg_msg(socket
,
632 lttng_alignof(uint8_t) * CHAR_BIT
,
633 lttng_alignof(uint16_t) * CHAR_BIT
,
634 lttng_alignof(uint32_t) * CHAR_BIT
,
635 lttng_alignof(uint64_t) * CHAR_BIT
,
636 lttng_alignof(unsigned long) * CHAR_BIT
);
640 int send_reply(int sock
, struct ustcomm_ust_reply
*lur
)
644 len
= ustcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
647 DBG("message successfully sent");
650 if (len
== -ECONNRESET
) {
651 DBG("remote end closed connection");
656 DBG("incorrect message size: %zd", len
);
662 void decrement_sem_count(unsigned int count
)
666 assert(uatomic_read(&sem_count
) >= count
);
668 if (uatomic_read(&sem_count
) <= 0) {
672 ret
= uatomic_add_return(&sem_count
, -count
);
674 ret
= sem_post(&constructor_wait
);
680 int handle_register_done(struct sock_info
*sock_info
)
682 if (sock_info
->registration_done
)
684 sock_info
->registration_done
= 1;
686 decrement_sem_count(1);
687 if (!sock_info
->statedump_pending
) {
688 sock_info
->initial_statedump_done
= 1;
689 decrement_sem_count(1);
696 int handle_register_failed(struct sock_info
*sock_info
)
698 if (sock_info
->registration_done
)
700 sock_info
->registration_done
= 1;
701 sock_info
->initial_statedump_done
= 1;
703 decrement_sem_count(2);
709 * Only execute pending statedump after the constructor semaphore has
710 * been posted by the current listener thread. This means statedump will
711 * only be performed after the "registration done" command is received
712 * from this thread's session daemon.
714 * This ensures we don't run into deadlock issues with the dynamic
715 * loader mutex, which is held while the constructor is called and
716 * waiting on the constructor semaphore. All operations requiring this
717 * dynamic loader lock need to be postponed using this mechanism.
719 * In a scenario with two session daemons connected to the application,
720 * it is possible that the first listener thread which receives the
721 * registration done command issues its statedump while the dynamic
722 * loader lock is still held by the application constructor waiting on
723 * the semaphore. It will however be allowed to proceed when the
724 * second session daemon sends the registration done command to the
725 * second listener thread. This situation therefore does not produce
729 void handle_pending_statedump(struct sock_info
*sock_info
)
731 if (sock_info
->registration_done
&& sock_info
->statedump_pending
) {
732 sock_info
->statedump_pending
= 0;
733 pthread_mutex_lock(&ust_fork_mutex
);
734 lttng_handle_pending_statedump(sock_info
);
735 pthread_mutex_unlock(&ust_fork_mutex
);
737 if (!sock_info
->initial_statedump_done
) {
738 sock_info
->initial_statedump_done
= 1;
739 decrement_sem_count(1);
745 const char *bytecode_type_str(uint32_t cmd
)
748 case LTTNG_UST_CAPTURE
:
750 case LTTNG_UST_FILTER
:
758 int handle_bytecode_recv(struct sock_info
*sock_info
,
759 int sock
, struct ustcomm_ust_msg
*lum
)
761 struct lttng_ust_bytecode_node
*bytecode
;
762 enum lttng_ust_bytecode_node_type type
;
763 const struct lttng_ust_objd_ops
*ops
;
764 uint32_t data_size
, data_size_max
, reloc_offset
;
770 case LTTNG_UST_FILTER
:
771 type
= LTTNG_UST_BYTECODE_NODE_TYPE_FILTER
;
772 data_size
= lum
->u
.filter
.data_size
;
773 data_size_max
= FILTER_BYTECODE_MAX_LEN
;
774 reloc_offset
= lum
->u
.filter
.reloc_offset
;
775 seqnum
= lum
->u
.filter
.seqnum
;
777 case LTTNG_UST_CAPTURE
:
778 type
= LTTNG_UST_BYTECODE_NODE_TYPE_CAPTURE
;
779 data_size
= lum
->u
.capture
.data_size
;
780 data_size_max
= CAPTURE_BYTECODE_MAX_LEN
;
781 reloc_offset
= lum
->u
.capture
.reloc_offset
;
782 seqnum
= lum
->u
.capture
.seqnum
;
788 if (data_size
> data_size_max
) {
789 ERR("Bytecode %s data size is too large: %u bytes",
790 bytecode_type_str(lum
->cmd
), data_size
);
795 if (reloc_offset
> data_size
) {
796 ERR("Bytecode %s reloc offset %u is not within data",
797 bytecode_type_str(lum
->cmd
), reloc_offset
);
802 /* Allocate the structure AND the `data[]` field. */
803 bytecode
= zmalloc(sizeof(*bytecode
) + data_size
);
809 bytecode
->bc
.len
= data_size
;
810 bytecode
->bc
.reloc_offset
= reloc_offset
;
811 bytecode
->bc
.seqnum
= seqnum
;
812 bytecode
->type
= type
;
814 len
= ustcomm_recv_unix_sock(sock
, bytecode
->bc
.data
, bytecode
->bc
.len
);
816 case 0: /* orderly shutdown */
818 goto error_free_bytecode
;
820 if (len
== bytecode
->bc
.len
) {
821 DBG("Bytecode %s data received",
822 bytecode_type_str(lum
->cmd
));
824 } else if (len
< 0) {
825 DBG("Receive failed from lttng-sessiond with errno %d",
827 if (len
== -ECONNRESET
) {
828 ERR("%s remote end closed connection",
831 goto error_free_bytecode
;
834 goto error_free_bytecode
;
836 DBG("Incorrect %s bytecode data message size: %zd",
837 bytecode_type_str(lum
->cmd
), len
);
839 goto error_free_bytecode
;
843 ops
= objd_ops(lum
->handle
);
846 goto error_free_bytecode
;
850 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
851 (unsigned long) bytecode
,
854 goto error_free_bytecode
;
855 /* don't free bytecode if everything went fine. */
858 goto error_free_bytecode
;
870 int handle_message(struct sock_info
*sock_info
,
871 int sock
, struct ustcomm_ust_msg
*lum
)
874 const struct lttng_ust_objd_ops
*ops
;
875 struct ustcomm_ust_reply lur
;
877 char ctxstr
[LTTNG_UST_SYM_NAME_LEN
]; /* App context string. */
880 memset(&lur
, 0, sizeof(lur
));
883 ret
= -LTTNG_UST_ERR_EXITING
;
887 ops
= objd_ops(lum
->handle
);
894 case LTTNG_UST_REGISTER_DONE
:
895 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
896 ret
= handle_register_done(sock_info
);
900 case LTTNG_UST_RELEASE
:
901 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
904 ret
= lttng_ust_objd_unref(lum
->handle
, 1);
906 case LTTNG_UST_CAPTURE
:
907 case LTTNG_UST_FILTER
:
908 ret
= handle_bytecode_recv(sock_info
, sock
, lum
);
912 case LTTNG_UST_EXCLUSION
:
914 /* Receive exclusion names */
915 struct lttng_ust_excluder_node
*node
;
918 count
= lum
->u
.exclusion
.count
;
920 /* There are no names to read */
924 node
= zmalloc(sizeof(*node
) +
925 count
* LTTNG_UST_SYM_NAME_LEN
);
930 node
->excluder
.count
= count
;
931 len
= ustcomm_recv_unix_sock(sock
, node
->excluder
.names
,
932 count
* LTTNG_UST_SYM_NAME_LEN
);
934 case 0: /* orderly shutdown */
939 if (len
== count
* LTTNG_UST_SYM_NAME_LEN
) {
940 DBG("Exclusion data received");
942 } else if (len
< 0) {
943 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
944 if (len
== -ECONNRESET
) {
945 ERR("%s remote end closed connection", sock_info
->name
);
954 DBG("Incorrect exclusion data message size: %zd", len
);
961 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
962 (unsigned long) node
,
967 /* Don't free exclusion data if everything went fine. */
974 case LTTNG_UST_TRIGGER_GROUP_CREATE
:
976 int trigger_notif_fd
;
978 len
= ustcomm_recv_trigger_notif_fd_from_sessiond(sock
,
981 case 0: /* orderly shutdown */
988 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
989 if (len
== -ECONNRESET
) {
990 ERR("%s remote end closed connection", sock_info
->name
);
997 DBG("incorrect trigger fd message size: %zd", len
);
1002 args
.trigger_handle
.trigger_notif_fd
= trigger_notif_fd
;
1004 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1005 (unsigned long) &lum
->u
,
1011 case LTTNG_UST_CHANNEL
:
1016 len
= ustcomm_recv_channel_from_sessiond(sock
,
1017 &chan_data
, lum
->u
.channel
.len
,
1020 case 0: /* orderly shutdown */
1024 if (len
== lum
->u
.channel
.len
) {
1025 DBG("channel data received");
1027 } else if (len
< 0) {
1028 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1029 if (len
== -ECONNRESET
) {
1030 ERR("%s remote end closed connection", sock_info
->name
);
1037 DBG("incorrect channel data message size: %zd", len
);
1042 args
.channel
.chan_data
= chan_data
;
1043 args
.channel
.wakeup_fd
= wakeup_fd
;
1045 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1046 (unsigned long) &lum
->u
,
1052 case LTTNG_UST_STREAM
:
1054 /* Receive shm_fd, wakeup_fd */
1055 ret
= ustcomm_recv_stream_from_sessiond(sock
,
1057 &args
.stream
.shm_fd
,
1058 &args
.stream
.wakeup_fd
);
1064 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1065 (unsigned long) &lum
->u
,
1071 case LTTNG_UST_CONTEXT
:
1072 switch (lum
->u
.context
.ctx
) {
1073 case LTTNG_UST_CONTEXT_APP_CONTEXT
:
1076 size_t ctxlen
, recvlen
;
1078 ctxlen
= strlen("$app.") + lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1
1079 + strlen(":") + lum
->u
.context
.u
.app_ctx
.ctx_name_len
;
1080 if (ctxlen
>= LTTNG_UST_SYM_NAME_LEN
) {
1081 ERR("Application context string length size is too large: %zu bytes",
1086 strcpy(ctxstr
, "$app.");
1087 p
= &ctxstr
[strlen("$app.")];
1088 recvlen
= ctxlen
- strlen("$app.");
1089 len
= ustcomm_recv_unix_sock(sock
, p
, recvlen
);
1091 case 0: /* orderly shutdown */
1095 if (len
== recvlen
) {
1096 DBG("app context data received");
1098 } else if (len
< 0) {
1099 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1100 if (len
== -ECONNRESET
) {
1101 ERR("%s remote end closed connection", sock_info
->name
);
1108 DBG("incorrect app context data message size: %zd", len
);
1113 /* Put : between provider and ctxname. */
1114 p
[lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1] = ':';
1115 args
.app_context
.ctxname
= ctxstr
;
1122 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1123 (unsigned long) &lum
->u
,
1131 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1132 (unsigned long) &lum
->u
,
1139 lur
.handle
= lum
->handle
;
1143 lur
.ret_code
= LTTNG_UST_OK
;
1146 * Use -LTTNG_UST_ERR as wildcard for UST internal
1147 * error that are not caused by the transport, except if
1148 * we already have a more precise error message to
1151 if (ret
> -LTTNG_UST_ERR
) {
1152 /* Translate code to UST error. */
1155 lur
.ret_code
= -LTTNG_UST_ERR_EXIST
;
1158 lur
.ret_code
= -LTTNG_UST_ERR_INVAL
;
1161 lur
.ret_code
= -LTTNG_UST_ERR_NOENT
;
1164 lur
.ret_code
= -LTTNG_UST_ERR_PERM
;
1167 lur
.ret_code
= -LTTNG_UST_ERR_NOSYS
;
1170 lur
.ret_code
= -LTTNG_UST_ERR
;
1179 case LTTNG_UST_TRACER_VERSION
:
1180 lur
.u
.version
= lum
->u
.version
;
1182 case LTTNG_UST_TRACEPOINT_LIST_GET
:
1183 memcpy(&lur
.u
.tracepoint
, &lum
->u
.tracepoint
, sizeof(lur
.u
.tracepoint
));
1187 DBG("Return value: %d", lur
.ret_val
);
1192 * Performed delayed statedump operations outside of the UST
1193 * lock. We need to take the dynamic loader lock before we take
1194 * the UST lock internally within handle_pending_statedump().
1196 handle_pending_statedump(sock_info
);
1199 ret
= -LTTNG_UST_ERR_EXITING
;
1203 ret
= send_reply(sock
, &lur
);
1205 DBG("error sending reply");
1210 * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field
1213 if (lur
.ret_code
== LTTNG_UST_OK
) {
1215 case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
:
1216 len
= ustcomm_send_unix_sock(sock
,
1217 &args
.field_list
.entry
,
1218 sizeof(args
.field_list
.entry
));
1223 if (len
!= sizeof(args
.field_list
.entry
)) {
1237 void cleanup_sock_info(struct sock_info
*sock_info
, int exiting
)
1241 if (sock_info
->root_handle
!= -1) {
1242 ret
= lttng_ust_objd_unref(sock_info
->root_handle
, 1);
1244 ERR("Error unref root handle");
1246 sock_info
->root_handle
= -1;
1248 sock_info
->registration_done
= 0;
1249 sock_info
->initial_statedump_done
= 0;
1252 * wait_shm_mmap, socket and notify socket are used by listener
1253 * threads outside of the ust lock, so we cannot tear them down
1254 * ourselves, because we cannot join on these threads. Leave
1255 * responsibility of cleaning up these resources to the OS
1261 if (sock_info
->socket
!= -1) {
1262 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1264 ERR("Error closing ust cmd socket");
1266 sock_info
->socket
= -1;
1268 if (sock_info
->notify_socket
!= -1) {
1269 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1271 ERR("Error closing ust notify socket");
1273 sock_info
->notify_socket
= -1;
1275 if (sock_info
->wait_shm_mmap
) {
1278 page_size
= sysconf(_SC_PAGE_SIZE
);
1279 if (page_size
<= 0) {
1283 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1285 ret
= munmap(sock_info
->wait_shm_mmap
, page_size
);
1287 ERR("Error unmapping wait shm");
1290 sock_info
->wait_shm_mmap
= NULL
;
1295 * Using fork to set umask in the child process (not multi-thread safe).
1296 * We deal with the shm_open vs ftruncate race (happening when the
1297 * sessiond owns the shm and does not let everybody modify it, to ensure
1298 * safety against shm_unlink) by simply letting the mmap fail and
1299 * retrying after a few seconds.
1300 * For global shm, everybody has rw access to it until the sessiond
1304 int get_wait_shm(struct sock_info
*sock_info
, size_t mmap_size
)
1306 int wait_shm_fd
, ret
;
1310 * Try to open read-only.
1312 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1313 if (wait_shm_fd
>= 0) {
1316 size_t bytes_read
= 0;
1319 * Try to read the fd. If unable to do so, try opening
1323 len
= read(wait_shm_fd
,
1324 &((char *) &tmp_read
)[bytes_read
],
1325 sizeof(tmp_read
) - bytes_read
);
1329 } while ((len
< 0 && errno
== EINTR
)
1330 || (len
> 0 && bytes_read
< sizeof(tmp_read
)));
1331 if (bytes_read
!= sizeof(tmp_read
)) {
1332 ret
= close(wait_shm_fd
);
1334 ERR("close wait_shm_fd");
1339 } else if (wait_shm_fd
< 0 && errno
!= ENOENT
) {
1341 * Real-only open did not work, and it's not because the
1342 * entry was not present. It's a failure that prohibits
1345 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1351 * If the open failed because the file did not exist, or because
1352 * the file was not truncated yet, try creating it ourself.
1354 URCU_TLS(lttng_ust_nest_count
)++;
1356 URCU_TLS(lttng_ust_nest_count
)--;
1361 * Parent: wait for child to return, in which case the
1362 * shared memory map will have been created.
1364 pid
= wait(&status
);
1365 if (pid
< 0 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0) {
1370 * Try to open read-only again after creation.
1372 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1373 if (wait_shm_fd
< 0) {
1375 * Real-only open did not work. It's a failure
1376 * that prohibits using shm.
1378 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1382 } else if (pid
== 0) {
1386 create_mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
;
1387 if (sock_info
->global
)
1388 create_mode
|= S_IROTH
| S_IWGRP
| S_IWOTH
;
1390 * We're alone in a child process, so we can modify the
1391 * process-wide umask.
1393 umask(~create_mode
);
1395 * Try creating shm (or get rw access).
1396 * We don't do an exclusive open, because we allow other
1397 * processes to create+ftruncate it concurrently.
1399 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
,
1400 O_RDWR
| O_CREAT
, create_mode
);
1401 if (wait_shm_fd
>= 0) {
1402 ret
= ftruncate(wait_shm_fd
, mmap_size
);
1404 PERROR("ftruncate");
1405 _exit(EXIT_FAILURE
);
1407 _exit(EXIT_SUCCESS
);
1410 * For local shm, we need to have rw access to accept
1411 * opening it: this means the local sessiond will be
1412 * able to wake us up. For global shm, we open it even
1413 * if rw access is not granted, because the root.root
1414 * sessiond will be able to override all rights and wake
1417 if (!sock_info
->global
&& errno
!= EACCES
) {
1418 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1419 _exit(EXIT_FAILURE
);
1422 * The shm exists, but we cannot open it RW. Report
1425 _exit(EXIT_SUCCESS
);
1430 if (wait_shm_fd
>= 0 && !sock_info
->global
) {
1431 struct stat statbuf
;
1434 * Ensure that our user is the owner of the shm file for
1435 * local shm. If we do not own the file, it means our
1436 * sessiond will not have access to wake us up (there is
1437 * probably a rogue process trying to fake our
1438 * sessiond). Fallback to polling method in this case.
1440 ret
= fstat(wait_shm_fd
, &statbuf
);
1445 if (statbuf
.st_uid
!= getuid())
1451 ret
= close(wait_shm_fd
);
1453 PERROR("Error closing fd");
1459 char *get_map_shm(struct sock_info
*sock_info
)
1462 int wait_shm_fd
, ret
;
1463 char *wait_shm_mmap
;
1465 page_size
= sysconf(_SC_PAGE_SIZE
);
1466 if (page_size
<= 0) {
1470 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1474 lttng_ust_lock_fd_tracker();
1475 wait_shm_fd
= get_wait_shm(sock_info
, page_size
);
1476 if (wait_shm_fd
< 0) {
1477 lttng_ust_unlock_fd_tracker();
1481 ret
= lttng_ust_add_fd_to_tracker(wait_shm_fd
);
1483 ret
= close(wait_shm_fd
);
1485 PERROR("Error closing fd");
1487 lttng_ust_unlock_fd_tracker();
1492 lttng_ust_unlock_fd_tracker();
1494 wait_shm_mmap
= mmap(NULL
, page_size
, PROT_READ
,
1495 MAP_SHARED
, wait_shm_fd
, 0);
1497 /* close shm fd immediately after taking the mmap reference */
1498 lttng_ust_lock_fd_tracker();
1499 ret
= close(wait_shm_fd
);
1501 lttng_ust_delete_fd_from_tracker(wait_shm_fd
);
1503 PERROR("Error closing fd");
1505 lttng_ust_unlock_fd_tracker();
1507 if (wait_shm_mmap
== MAP_FAILED
) {
1508 DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
1511 return wait_shm_mmap
;
1518 void wait_for_sessiond(struct sock_info
*sock_info
)
1520 /* Use ust_lock to check if we should quit. */
1524 if (wait_poll_fallback
) {
1529 assert(sock_info
->wait_shm_mmap
);
1531 DBG("Waiting for %s apps sessiond", sock_info
->name
);
1532 /* Wait for futex wakeup */
1533 if (uatomic_read((int32_t *) sock_info
->wait_shm_mmap
))
1536 while (futex_async((int32_t *) sock_info
->wait_shm_mmap
,
1537 FUTEX_WAIT
, 0, NULL
, NULL
, 0)) {
1540 /* Value already changed. */
1543 /* Retry if interrupted by signal. */
1544 break; /* Get out of switch. */
1546 wait_poll_fallback
= 1;
1548 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
1549 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
1550 "Please upgrade your kernel "
1551 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
1552 "mainline). LTTng-UST will use polling mode fallback.");
1571 * This thread does not allocate any resource, except within
1572 * handle_message, within mutex protection. This mutex protects against
1574 * The other moment it allocates resources is at socket connection, which
1575 * is also protected by the mutex.
1578 void *ust_listener_thread(void *arg
)
1580 struct sock_info
*sock_info
= arg
;
1581 int sock
, ret
, prev_connect_failed
= 0, has_waited
= 0, fd
;
1584 lttng_ust_fixup_tls();
1586 * If available, add '-ust' to the end of this thread's
1589 ret
= lttng_ust_setustprocname();
1591 ERR("Unable to set UST process name");
1594 /* Restart trying to connect to the session daemon */
1596 if (prev_connect_failed
) {
1597 /* Wait for sessiond availability with pipe */
1598 wait_for_sessiond(sock_info
);
1602 * Sleep for 5 seconds before retrying after a
1603 * sequence of failure / wait / failure. This
1604 * deals with a killed or broken session daemon.
1610 prev_connect_failed
= 0;
1617 if (sock_info
->socket
!= -1) {
1618 /* FD tracker is updated by ustcomm_close_unix_sock() */
1619 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1621 ERR("Error closing %s ust cmd socket",
1624 sock_info
->socket
= -1;
1626 if (sock_info
->notify_socket
!= -1) {
1627 /* FD tracker is updated by ustcomm_close_unix_sock() */
1628 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1630 ERR("Error closing %s ust notify socket",
1633 sock_info
->notify_socket
= -1;
1638 * Register. We need to perform both connect and sending
1639 * registration message before doing the next connect otherwise
1640 * we may reach unix socket connect queue max limits and block
1641 * on the 2nd connect while the session daemon is awaiting the
1642 * first connect registration message.
1644 /* Connect cmd socket */
1645 lttng_ust_lock_fd_tracker();
1646 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1647 get_connect_sock_timeout());
1649 lttng_ust_unlock_fd_tracker();
1650 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1651 prev_connect_failed
= 1;
1654 * If we cannot find the sessiond daemon, don't delay
1655 * constructor execution.
1657 ret
= handle_register_failed(sock_info
);
1663 ret
= lttng_ust_add_fd_to_tracker(fd
);
1667 PERROR("close on sock_info->socket");
1670 lttng_ust_unlock_fd_tracker();
1675 sock_info
->socket
= ret
;
1676 lttng_ust_unlock_fd_tracker();
1680 * Unlock/relock ust lock because connect is blocking (with
1681 * timeout). Don't delay constructors on the ust lock for too
1689 * Create only one root handle per listener thread for the whole
1690 * process lifetime, so we ensure we get ID which is statically
1691 * assigned to the root handle.
1693 if (sock_info
->root_handle
== -1) {
1694 ret
= lttng_abi_create_root_handle();
1696 ERR("Error creating root handle");
1699 sock_info
->root_handle
= ret
;
1702 ret
= register_to_sessiond(sock_info
->socket
, USTCTL_SOCKET_CMD
);
1704 ERR("Error registering to %s ust cmd socket",
1706 prev_connect_failed
= 1;
1708 * If we cannot register to the sessiond daemon, don't
1709 * delay constructor execution.
1711 ret
= handle_register_failed(sock_info
);
1719 * Unlock/relock ust lock because connect is blocking (with
1720 * timeout). Don't delay constructors on the ust lock for too
1727 /* Connect notify socket */
1728 lttng_ust_lock_fd_tracker();
1729 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1730 get_connect_sock_timeout());
1732 lttng_ust_unlock_fd_tracker();
1733 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1734 prev_connect_failed
= 1;
1737 * If we cannot find the sessiond daemon, don't delay
1738 * constructor execution.
1740 ret
= handle_register_failed(sock_info
);
1747 ret
= lttng_ust_add_fd_to_tracker(fd
);
1751 PERROR("close on sock_info->notify_socket");
1754 lttng_ust_unlock_fd_tracker();
1759 sock_info
->notify_socket
= ret
;
1760 lttng_ust_unlock_fd_tracker();
1764 * Unlock/relock ust lock because connect is blocking (with
1765 * timeout). Don't delay constructors on the ust lock for too
1772 timeout
= get_notify_sock_timeout();
1775 * Give at least 10ms to sessiond to reply to
1780 ret
= ustcomm_setsockopt_rcv_timeout(sock_info
->notify_socket
,
1783 WARN("Error setting socket receive timeout");
1785 ret
= ustcomm_setsockopt_snd_timeout(sock_info
->notify_socket
,
1788 WARN("Error setting socket send timeout");
1790 } else if (timeout
< -1) {
1791 WARN("Unsupported timeout value %ld", timeout
);
1794 ret
= register_to_sessiond(sock_info
->notify_socket
,
1795 USTCTL_SOCKET_NOTIFY
);
1797 ERR("Error registering to %s ust notify socket",
1799 prev_connect_failed
= 1;
1801 * If we cannot register to the sessiond daemon, don't
1802 * delay constructor execution.
1804 ret
= handle_register_failed(sock_info
);
1809 sock
= sock_info
->socket
;
1815 struct ustcomm_ust_msg lum
;
1817 len
= ustcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
1819 case 0: /* orderly shutdown */
1820 DBG("%s lttng-sessiond has performed an orderly shutdown", sock_info
->name
);
1825 * Either sessiond has shutdown or refused us by closing the socket.
1826 * In either case, we don't want to delay construction execution,
1827 * and we need to wait before retry.
1829 prev_connect_failed
= 1;
1831 * If we cannot register to the sessiond daemon, don't
1832 * delay constructor execution.
1834 ret
= handle_register_failed(sock_info
);
1839 print_cmd(lum
.cmd
, lum
.handle
);
1840 ret
= handle_message(sock_info
, sock
, &lum
);
1842 ERR("Error handling message for %s socket",
1845 * Close socket if protocol error is
1853 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1855 DBG("incorrect message size (%s socket): %zd", sock_info
->name
, len
);
1857 if (len
== -ECONNRESET
) {
1858 DBG("%s remote end closed connection", sock_info
->name
);
1869 /* Cleanup socket handles before trying to reconnect */
1870 lttng_ust_objd_table_owner_cleanup(sock_info
);
1872 goto restart
; /* try to reconnect */
1877 pthread_mutex_lock(&ust_exit_mutex
);
1878 sock_info
->thread_active
= 0;
1879 pthread_mutex_unlock(&ust_exit_mutex
);
1884 * Weak symbol to call when the ust malloc wrapper is not loaded.
1886 __attribute__((weak
))
1887 void lttng_ust_malloc_wrapper_init(void)
1892 * sessiond monitoring thread: monitor presence of global and per-user
1893 * sessiond by polling the application common named pipe.
1895 void __attribute__((constructor
)) lttng_ust_init(void)
1897 struct timespec constructor_timeout
;
1898 sigset_t sig_all_blocked
, orig_parent_mask
;
1899 pthread_attr_t thread_attr
;
1904 if (uatomic_xchg(&initialized
, 1) == 1)
1908 * Fixup interdependency between TLS fixup mutex (which happens
1909 * to be the dynamic linker mutex) and ust_lock, taken within
1912 lttng_ust_fixup_tls();
1914 lttng_ust_loaded
= 1;
1917 * We need to ensure that the liblttng-ust library is not unloaded to avoid
1918 * the unloading of code used by the ust_listener_threads as we can not
1919 * reliably know when they exited. To do that, manually load
1920 * liblttng-ust.so to increment the dynamic loader's internal refcount for
1921 * this library so it never becomes zero, thus never gets unloaded from the
1922 * address space of the process. Since we are already running in the
1923 * constructor of the LTTNG_UST_LIB_SO_NAME library, calling dlopen will
1924 * simply increment the refcount and no additionnal work is needed by the
1925 * dynamic loader as the shared library is already loaded in the address
1926 * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
1927 * unloading of the UST library if its refcount becomes zero (which should
1928 * never happen). Do the return value check but discard the handle at the
1929 * end of the function as it's not needed.
1931 handle
= dlopen(LTTNG_UST_LIB_SO_NAME
, RTLD_LAZY
| RTLD_NODELETE
);
1933 ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SO_NAME
);
1937 * We want precise control over the order in which we construct
1938 * our sub-libraries vs starting to receive commands from
1939 * sessiond (otherwise leading to errors when trying to create
1940 * sessiond before the init functions are completed).
1943 lttng_ust_getenv_init(); /* Needs init_usterr() to be completed. */
1945 lttng_ust_init_fd_tracker();
1946 lttng_ust_clock_init();
1947 lttng_ust_getcpu_init();
1948 lttng_ust_statedump_init();
1949 lttng_ring_buffer_metadata_client_init();
1950 lttng_ring_buffer_client_overwrite_init();
1951 lttng_ring_buffer_client_overwrite_rt_init();
1952 lttng_ring_buffer_client_discard_init();
1953 lttng_ring_buffer_client_discard_rt_init();
1954 lttng_perf_counter_init();
1956 * Invoke ust malloc wrapper init before starting other threads.
1958 lttng_ust_malloc_wrapper_init();
1960 timeout_mode
= get_constructor_timeout(&constructor_timeout
);
1962 get_allow_blocking();
1964 ret
= sem_init(&constructor_wait
, 0, 0);
1969 ret
= setup_global_apps();
1971 assert(global_apps
.allowed
== 0);
1972 DBG("global apps setup returned %d", ret
);
1975 ret
= setup_local_apps();
1977 assert(local_apps
.allowed
== 0);
1978 DBG("local apps setup returned %d", ret
);
1981 /* A new thread created by pthread_create inherits the signal mask
1982 * from the parent. To avoid any signal being received by the
1983 * listener thread, we block all signals temporarily in the parent,
1984 * while we create the listener thread.
1986 sigfillset(&sig_all_blocked
);
1987 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_parent_mask
);
1989 ERR("pthread_sigmask: %s", strerror(ret
));
1992 ret
= pthread_attr_init(&thread_attr
);
1994 ERR("pthread_attr_init: %s", strerror(ret
));
1996 ret
= pthread_attr_setdetachstate(&thread_attr
, PTHREAD_CREATE_DETACHED
);
1998 ERR("pthread_attr_setdetachstate: %s", strerror(ret
));
2001 if (global_apps
.allowed
) {
2002 pthread_mutex_lock(&ust_exit_mutex
);
2003 ret
= pthread_create(&global_apps
.ust_listener
, &thread_attr
,
2004 ust_listener_thread
, &global_apps
);
2006 ERR("pthread_create global: %s", strerror(ret
));
2008 global_apps
.thread_active
= 1;
2009 pthread_mutex_unlock(&ust_exit_mutex
);
2011 handle_register_done(&global_apps
);
2014 if (local_apps
.allowed
) {
2015 pthread_mutex_lock(&ust_exit_mutex
);
2016 ret
= pthread_create(&local_apps
.ust_listener
, &thread_attr
,
2017 ust_listener_thread
, &local_apps
);
2019 ERR("pthread_create local: %s", strerror(ret
));
2021 local_apps
.thread_active
= 1;
2022 pthread_mutex_unlock(&ust_exit_mutex
);
2024 handle_register_done(&local_apps
);
2026 ret
= pthread_attr_destroy(&thread_attr
);
2028 ERR("pthread_attr_destroy: %s", strerror(ret
));
2031 /* Restore original signal mask in parent */
2032 ret
= pthread_sigmask(SIG_SETMASK
, &orig_parent_mask
, NULL
);
2034 ERR("pthread_sigmask: %s", strerror(ret
));
2037 switch (timeout_mode
) {
2038 case 1: /* timeout wait */
2040 ret
= sem_timedwait(&constructor_wait
,
2041 &constructor_timeout
);
2042 } while (ret
< 0 && errno
== EINTR
);
2046 ERR("Timed out waiting for lttng-sessiond");
2049 PERROR("sem_timedwait");
2052 ERR("Unexpected error \"%s\" returned by sem_timedwait",
2057 case -1:/* wait forever */
2059 ret
= sem_wait(&constructor_wait
);
2060 } while (ret
< 0 && errno
== EINTR
);
2067 ERR("Unexpected error \"%s\" returned by sem_wait",
2072 case 0: /* no timeout */
2078 void lttng_ust_cleanup(int exiting
)
2080 cleanup_sock_info(&global_apps
, exiting
);
2081 cleanup_sock_info(&local_apps
, exiting
);
2082 local_apps
.allowed
= 0;
2083 global_apps
.allowed
= 0;
2085 * The teardown in this function all affect data structures
2086 * accessed under the UST lock by the listener thread. This
2087 * lock, along with the lttng_ust_comm_should_quit flag, ensure
2088 * that none of these threads are accessing this data at this
2091 lttng_ust_abi_exit();
2092 lttng_ust_events_exit();
2093 lttng_perf_counter_exit();
2094 lttng_ring_buffer_client_discard_rt_exit();
2095 lttng_ring_buffer_client_discard_exit();
2096 lttng_ring_buffer_client_overwrite_rt_exit();
2097 lttng_ring_buffer_client_overwrite_exit();
2098 lttng_ring_buffer_metadata_client_exit();
2099 lttng_ust_statedump_destroy();
2102 /* Reinitialize values for fork */
2103 sem_count
= sem_count_initial_value
;
2104 lttng_ust_comm_should_quit
= 0;
2109 void __attribute__((destructor
)) lttng_ust_exit(void)
2114 * Using pthread_cancel here because:
2115 * A) we don't want to hang application teardown.
2116 * B) the thread is not allocating any resource.
2120 * Require the communication thread to quit. Synchronize with
2121 * mutexes to ensure it is not in a mutex critical section when
2122 * pthread_cancel is later called.
2125 lttng_ust_comm_should_quit
= 1;
2128 pthread_mutex_lock(&ust_exit_mutex
);
2129 /* cancel threads */
2130 if (global_apps
.thread_active
) {
2131 ret
= pthread_cancel(global_apps
.ust_listener
);
2133 ERR("Error cancelling global ust listener thread: %s",
2136 global_apps
.thread_active
= 0;
2139 if (local_apps
.thread_active
) {
2140 ret
= pthread_cancel(local_apps
.ust_listener
);
2142 ERR("Error cancelling local ust listener thread: %s",
2145 local_apps
.thread_active
= 0;
2148 pthread_mutex_unlock(&ust_exit_mutex
);
2151 * Do NOT join threads: use of sys_futex makes it impossible to
2152 * join the threads without using async-cancel, but async-cancel
2153 * is delivered by a signal, which could hit the target thread
2154 * anywhere in its code path, including while the ust_lock() is
2155 * held, causing a deadlock for the other thread. Let the OS
2156 * cleanup the threads if there are stalled in a syscall.
2158 lttng_ust_cleanup(1);
2162 void ust_context_ns_reset(void)
2164 lttng_context_pid_ns_reset();
2165 lttng_context_cgroup_ns_reset();
2166 lttng_context_ipc_ns_reset();
2167 lttng_context_mnt_ns_reset();
2168 lttng_context_net_ns_reset();
2169 lttng_context_user_ns_reset();
2170 lttng_context_uts_ns_reset();
2174 void ust_context_vuids_reset(void)
2176 lttng_context_vuid_reset();
2177 lttng_context_veuid_reset();
2178 lttng_context_vsuid_reset();
2182 void ust_context_vgids_reset(void)
2184 lttng_context_vgid_reset();
2185 lttng_context_vegid_reset();
2186 lttng_context_vsgid_reset();
2190 * We exclude the worker threads across fork and clone (except
2191 * CLONE_VM), because these system calls only keep the forking thread
2192 * running in the child. Therefore, we don't want to call fork or clone
2193 * in the middle of an tracepoint or ust tracing state modification.
2194 * Holding this mutex protects these structures across fork and clone.
2196 void ust_before_fork(sigset_t
*save_sigset
)
2199 * Disable signals. This is to avoid that the child intervenes
2200 * before it is properly setup for tracing. It is safer to
2201 * disable all signals, because then we know we are not breaking
2202 * anything by restoring the original mask.
2207 /* Fixup lttng-ust TLS. */
2208 lttng_ust_fixup_tls();
2210 if (URCU_TLS(lttng_ust_nest_count
))
2212 /* Disable signals */
2213 sigfillset(&all_sigs
);
2214 ret
= sigprocmask(SIG_BLOCK
, &all_sigs
, save_sigset
);
2216 PERROR("sigprocmask");
2219 pthread_mutex_lock(&ust_fork_mutex
);
2222 urcu_bp_before_fork();
2223 lttng_ust_lock_fd_tracker();
2227 static void ust_after_fork_common(sigset_t
*restore_sigset
)
2231 DBG("process %d", getpid());
2232 lttng_perf_unlock();
2233 lttng_ust_unlock_fd_tracker();
2236 pthread_mutex_unlock(&ust_fork_mutex
);
2238 /* Restore signals */
2239 ret
= sigprocmask(SIG_SETMASK
, restore_sigset
, NULL
);
2241 PERROR("sigprocmask");
2245 void ust_after_fork_parent(sigset_t
*restore_sigset
)
2247 if (URCU_TLS(lttng_ust_nest_count
))
2249 DBG("process %d", getpid());
2250 urcu_bp_after_fork_parent();
2251 /* Release mutexes and reenable signals */
2252 ust_after_fork_common(restore_sigset
);
2256 * After fork, in the child, we need to cleanup all the leftover state,
2257 * except the worker thread which already magically disappeared thanks
2258 * to the weird Linux fork semantics. After tyding up, we call
2259 * lttng_ust_init() again to start over as a new PID.
2261 * This is meant for forks() that have tracing in the child between the
2262 * fork and following exec call (if there is any).
2264 void ust_after_fork_child(sigset_t
*restore_sigset
)
2266 if (URCU_TLS(lttng_ust_nest_count
))
2268 lttng_context_vpid_reset();
2269 lttng_context_vtid_reset();
2270 lttng_context_procname_reset();
2271 ust_context_ns_reset();
2272 ust_context_vuids_reset();
2273 ust_context_vgids_reset();
2274 DBG("process %d", getpid());
2275 /* Release urcu mutexes */
2276 urcu_bp_after_fork_child();
2277 lttng_ust_cleanup(0);
2278 /* Release mutexes and reenable signals */
2279 ust_after_fork_common(restore_sigset
);
2283 void ust_after_setns(void)
2285 ust_context_ns_reset();
2286 ust_context_vuids_reset();
2287 ust_context_vgids_reset();
2290 void ust_after_unshare(void)
2292 ust_context_ns_reset();
2293 ust_context_vuids_reset();
2294 ust_context_vgids_reset();
2297 void ust_after_setuid(void)
2299 ust_context_vuids_reset();
2302 void ust_after_seteuid(void)
2304 ust_context_vuids_reset();
2307 void ust_after_setreuid(void)
2309 ust_context_vuids_reset();
2312 void ust_after_setresuid(void)
2314 ust_context_vuids_reset();
2317 void ust_after_setgid(void)
2319 ust_context_vgids_reset();
2322 void ust_after_setegid(void)
2324 ust_context_vgids_reset();
2327 void ust_after_setregid(void)
2329 ust_context_vgids_reset();
2332 void ust_after_setresgid(void)
2334 ust_context_vgids_reset();
2337 void lttng_ust_sockinfo_session_enabled(void *owner
)
2339 struct sock_info
*sock_info
= owner
;
2340 sock_info
->statedump_pending
= 1;