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
25 #include <sys/types.h>
26 #include <sys/socket.h>
29 #include <sys/types.h>
36 #include <semaphore.h>
41 #include <urcu/uatomic.h>
42 #include <urcu/futex.h>
43 #include <urcu/compiler.h>
45 #include <lttng/align.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_ABI_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 /* Session FD commands */
325 [ LTTNG_UST_CHANNEL
] = "Create Channel",
326 [ LTTNG_UST_SESSION_START
] = "Start Session",
327 [ LTTNG_UST_SESSION_STOP
] = "Stop Session",
329 /* Channel FD commands */
330 [ LTTNG_UST_STREAM
] = "Create Stream",
331 [ LTTNG_UST_EVENT
] = "Create Event",
333 /* Event and Channel FD commands */
334 [ LTTNG_UST_CONTEXT
] = "Create Context",
335 [ LTTNG_UST_FLUSH_BUFFER
] = "Flush Buffer",
337 /* Event, Channel and Session commands */
338 [ LTTNG_UST_ENABLE
] = "Enable",
339 [ LTTNG_UST_DISABLE
] = "Disable",
341 /* Tracepoint list commands */
342 [ LTTNG_UST_TRACEPOINT_LIST_GET
] = "List Next Tracepoint",
343 [ LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
] = "List Next Tracepoint Field",
345 /* Event FD commands */
346 [ LTTNG_UST_FILTER
] = "Create Filter",
347 [ LTTNG_UST_EXCLUSION
] = "Add exclusions to event",
350 static const char *str_timeout
;
351 static int got_timeout_env
;
353 extern void lttng_ring_buffer_client_overwrite_init(void);
354 extern void lttng_ring_buffer_client_overwrite_rt_init(void);
355 extern void lttng_ring_buffer_client_discard_init(void);
356 extern void lttng_ring_buffer_client_discard_rt_init(void);
357 extern void lttng_ring_buffer_metadata_client_init(void);
358 extern void lttng_ring_buffer_client_overwrite_exit(void);
359 extern void lttng_ring_buffer_client_overwrite_rt_exit(void);
360 extern void lttng_ring_buffer_client_discard_exit(void);
361 extern void lttng_ring_buffer_client_discard_rt_exit(void);
362 extern void lttng_ring_buffer_metadata_client_exit(void);
364 static char *get_map_shm(struct sock_info
*sock_info
);
366 ssize_t
lttng_ust_read(int fd
, void *buf
, size_t len
)
369 size_t copied
= 0, to_copy
= len
;
372 ret
= read(fd
, buf
+ copied
, to_copy
);
377 } while ((ret
> 0 && to_copy
> 0)
378 || (ret
< 0 && errno
== EINTR
));
385 * Returns the HOME directory path. Caller MUST NOT free(3) the returned
389 const char *get_lttng_home_dir(void)
393 val
= (const char *) lttng_getenv("LTTNG_HOME");
397 return (const char *) lttng_getenv("HOME");
401 * Force a read (imply TLS fixup for dlopen) of TLS variables.
404 void lttng_fixup_nest_count_tls(void)
406 asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count
)));
410 void lttng_fixup_ust_mutex_nest_tls(void)
412 asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest
)));
419 void lttng_fixup_urcu_bp_tls(void)
425 void lttng_ust_fixup_tls(void)
427 lttng_fixup_urcu_bp_tls();
428 lttng_fixup_ringbuffer_tls();
429 lttng_fixup_vtid_tls();
430 lttng_fixup_nest_count_tls();
431 lttng_fixup_procname_tls();
432 lttng_fixup_ust_mutex_nest_tls();
433 lttng_ust_fixup_perf_counter_tls();
434 lttng_ust_fixup_fd_tracker_tls();
435 lttng_fixup_cgroup_ns_tls();
436 lttng_fixup_ipc_ns_tls();
437 lttng_fixup_net_ns_tls();
438 lttng_fixup_time_ns_tls();
439 lttng_fixup_uts_ns_tls();
442 int lttng_get_notify_socket(void *owner
)
444 struct sock_info
*info
= owner
;
446 return info
->notify_socket
;
451 char* lttng_ust_sockinfo_get_procname(void *owner
)
453 struct sock_info
*info
= owner
;
455 return info
->procname
;
459 void print_cmd(int cmd
, int handle
)
461 const char *cmd_name
= "Unknown";
463 if (cmd
>= 0 && cmd
< LTTNG_ARRAY_SIZE(cmd_name_mapping
)
464 && cmd_name_mapping
[cmd
]) {
465 cmd_name
= cmd_name_mapping
[cmd
];
467 DBG("Message Received \"%s\" (%d), Handle \"%s\" (%d)",
469 lttng_ust_obj_get_name(handle
), handle
);
473 int setup_global_apps(void)
476 assert(!global_apps
.wait_shm_mmap
);
478 global_apps
.wait_shm_mmap
= get_map_shm(&global_apps
);
479 if (!global_apps
.wait_shm_mmap
) {
480 WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
481 global_apps
.allowed
= 0;
486 global_apps
.allowed
= 1;
487 lttng_pthread_getname_np(global_apps
.procname
, LTTNG_UST_ABI_PROCNAME_LEN
);
492 int setup_local_apps(void)
495 const char *home_dir
;
498 assert(!local_apps
.wait_shm_mmap
);
502 * Disallow per-user tracing for setuid binaries.
504 if (uid
!= geteuid()) {
505 assert(local_apps
.allowed
== 0);
509 home_dir
= get_lttng_home_dir();
511 WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
512 assert(local_apps
.allowed
== 0);
516 local_apps
.allowed
= 1;
517 snprintf(local_apps
.sock_path
, PATH_MAX
, "%s/%s/%s",
519 LTTNG_DEFAULT_HOME_RUNDIR
,
520 LTTNG_UST_SOCK_FILENAME
);
521 snprintf(local_apps
.wait_shm_path
, PATH_MAX
, "/%s-%u",
522 LTTNG_UST_WAIT_FILENAME
,
525 local_apps
.wait_shm_mmap
= get_map_shm(&local_apps
);
526 if (!local_apps
.wait_shm_mmap
) {
527 WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
528 local_apps
.allowed
= 0;
533 lttng_pthread_getname_np(local_apps
.procname
, LTTNG_UST_ABI_PROCNAME_LEN
);
539 * Get socket timeout, in ms.
540 * -1: wait forever. 0: don't wait. >0: timeout, in ms.
543 long get_timeout(void)
545 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
547 if (!got_timeout_env
) {
548 str_timeout
= lttng_getenv("LTTNG_UST_REGISTER_TIMEOUT");
552 constructor_delay_ms
= strtol(str_timeout
, NULL
, 10);
553 /* All negative values are considered as "-1". */
554 if (constructor_delay_ms
< -1)
555 constructor_delay_ms
= -1;
556 return constructor_delay_ms
;
559 /* Timeout for notify socket send and recv. */
561 long get_notify_sock_timeout(void)
563 return get_timeout();
566 /* Timeout for connecting to cmd and notify sockets. */
568 long get_connect_sock_timeout(void)
570 return get_timeout();
574 * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
577 int get_constructor_timeout(struct timespec
*constructor_timeout
)
579 long constructor_delay_ms
;
582 constructor_delay_ms
= get_timeout();
584 switch (constructor_delay_ms
) {
585 case -1:/* fall-through */
587 return constructor_delay_ms
;
593 * If we are unable to find the current time, don't wait.
595 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
600 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
601 constructor_timeout
->tv_nsec
+=
602 (constructor_delay_ms
% 1000UL) * 1000000UL;
603 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
604 constructor_timeout
->tv_sec
++;
605 constructor_timeout
->tv_nsec
-= 1000000000UL;
607 /* Timeout wait (constructor_delay_ms). */
612 void get_allow_blocking(void)
614 const char *str_allow_blocking
=
615 lttng_getenv("LTTNG_UST_ALLOW_BLOCKING");
617 if (str_allow_blocking
) {
618 DBG("%s environment variable is set",
619 "LTTNG_UST_ALLOW_BLOCKING");
620 lttng_ust_ringbuffer_set_allow_blocking();
625 int register_to_sessiond(int socket
, enum ustctl_socket_type type
)
627 return ustcomm_send_reg_msg(socket
,
630 lttng_alignof(uint8_t) * CHAR_BIT
,
631 lttng_alignof(uint16_t) * CHAR_BIT
,
632 lttng_alignof(uint32_t) * CHAR_BIT
,
633 lttng_alignof(uint64_t) * CHAR_BIT
,
634 lttng_alignof(unsigned long) * CHAR_BIT
);
638 int send_reply(int sock
, struct ustcomm_ust_reply
*lur
)
642 len
= ustcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
645 DBG("message successfully sent");
648 if (len
== -ECONNRESET
) {
649 DBG("remote end closed connection");
654 DBG("incorrect message size: %zd", len
);
660 void decrement_sem_count(unsigned int count
)
664 assert(uatomic_read(&sem_count
) >= count
);
666 if (uatomic_read(&sem_count
) <= 0) {
670 ret
= uatomic_add_return(&sem_count
, -count
);
672 ret
= sem_post(&constructor_wait
);
678 int handle_register_done(struct sock_info
*sock_info
)
680 if (sock_info
->registration_done
)
682 sock_info
->registration_done
= 1;
684 decrement_sem_count(1);
685 if (!sock_info
->statedump_pending
) {
686 sock_info
->initial_statedump_done
= 1;
687 decrement_sem_count(1);
694 int handle_register_failed(struct sock_info
*sock_info
)
696 if (sock_info
->registration_done
)
698 sock_info
->registration_done
= 1;
699 sock_info
->initial_statedump_done
= 1;
701 decrement_sem_count(2);
707 * Only execute pending statedump after the constructor semaphore has
708 * been posted by the current listener thread. This means statedump will
709 * only be performed after the "registration done" command is received
710 * from this thread's session daemon.
712 * This ensures we don't run into deadlock issues with the dynamic
713 * loader mutex, which is held while the constructor is called and
714 * waiting on the constructor semaphore. All operations requiring this
715 * dynamic loader lock need to be postponed using this mechanism.
717 * In a scenario with two session daemons connected to the application,
718 * it is possible that the first listener thread which receives the
719 * registration done command issues its statedump while the dynamic
720 * loader lock is still held by the application constructor waiting on
721 * the semaphore. It will however be allowed to proceed when the
722 * second session daemon sends the registration done command to the
723 * second listener thread. This situation therefore does not produce
727 void handle_pending_statedump(struct sock_info
*sock_info
)
729 if (sock_info
->registration_done
&& sock_info
->statedump_pending
) {
730 sock_info
->statedump_pending
= 0;
731 pthread_mutex_lock(&ust_fork_mutex
);
732 lttng_handle_pending_statedump(sock_info
);
733 pthread_mutex_unlock(&ust_fork_mutex
);
735 if (!sock_info
->initial_statedump_done
) {
736 sock_info
->initial_statedump_done
= 1;
737 decrement_sem_count(1);
743 int handle_message(struct sock_info
*sock_info
,
744 int sock
, struct ustcomm_ust_msg
*lum
)
747 const struct lttng_ust_objd_ops
*ops
;
748 struct ustcomm_ust_reply lur
;
750 char ctxstr
[LTTNG_UST_SYM_NAME_LEN
]; /* App context string. */
753 memset(&lur
, 0, sizeof(lur
));
756 ret
= -LTTNG_UST_ERR_EXITING
;
760 ops
= objd_ops(lum
->handle
);
767 case LTTNG_UST_REGISTER_DONE
:
768 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
769 ret
= handle_register_done(sock_info
);
773 case LTTNG_UST_RELEASE
:
774 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
777 ret
= lttng_ust_objd_unref(lum
->handle
, 1);
779 case LTTNG_UST_FILTER
:
781 /* Receive filter data */
782 struct lttng_ust_filter_bytecode_node
*bytecode
;
784 if (lum
->u
.filter
.data_size
> FILTER_BYTECODE_MAX_LEN
) {
785 ERR("Filter data size is too large: %u bytes",
786 lum
->u
.filter
.data_size
);
791 if (lum
->u
.filter
.reloc_offset
> lum
->u
.filter
.data_size
) {
792 ERR("Filter reloc offset %u is not within data",
793 lum
->u
.filter
.reloc_offset
);
798 bytecode
= zmalloc(sizeof(*bytecode
) + lum
->u
.filter
.data_size
);
803 len
= ustcomm_recv_unix_sock(sock
, bytecode
->bc
.data
,
804 lum
->u
.filter
.data_size
);
806 case 0: /* orderly shutdown */
811 if (len
== lum
->u
.filter
.data_size
) {
812 DBG("filter data received");
814 } else if (len
< 0) {
815 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
816 if (len
== -ECONNRESET
) {
817 ERR("%s remote end closed connection", sock_info
->name
);
826 DBG("incorrect filter data message size: %zd", len
);
832 bytecode
->bc
.len
= lum
->u
.filter
.data_size
;
833 bytecode
->bc
.reloc_offset
= lum
->u
.filter
.reloc_offset
;
834 bytecode
->bc
.seqnum
= lum
->u
.filter
.seqnum
;
836 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
837 (unsigned long) bytecode
,
842 /* don't free bytecode if everything went fine. */
849 case LTTNG_UST_EXCLUSION
:
851 /* Receive exclusion names */
852 struct lttng_ust_excluder_node
*node
;
855 count
= lum
->u
.exclusion
.count
;
857 /* There are no names to read */
861 node
= zmalloc(sizeof(*node
) +
862 count
* LTTNG_UST_SYM_NAME_LEN
);
867 node
->excluder
.count
= count
;
868 len
= ustcomm_recv_unix_sock(sock
, node
->excluder
.names
,
869 count
* LTTNG_UST_SYM_NAME_LEN
);
871 case 0: /* orderly shutdown */
876 if (len
== count
* LTTNG_UST_SYM_NAME_LEN
) {
877 DBG("Exclusion data received");
879 } else if (len
< 0) {
880 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
881 if (len
== -ECONNRESET
) {
882 ERR("%s remote end closed connection", sock_info
->name
);
891 DBG("Incorrect exclusion data message size: %zd", len
);
898 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
899 (unsigned long) node
,
904 /* Don't free exclusion data if everything went fine. */
911 case LTTNG_UST_CHANNEL
:
916 len
= ustcomm_recv_channel_from_sessiond(sock
,
917 &chan_data
, lum
->u
.channel
.len
,
920 case 0: /* orderly shutdown */
924 if (len
== lum
->u
.channel
.len
) {
925 DBG("channel data received");
927 } else if (len
< 0) {
928 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
929 if (len
== -ECONNRESET
) {
930 ERR("%s remote end closed connection", sock_info
->name
);
937 DBG("incorrect channel data message size: %zd", len
);
942 args
.channel
.chan_data
= chan_data
;
943 args
.channel
.wakeup_fd
= wakeup_fd
;
945 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
946 (unsigned long) &lum
->u
,
952 case LTTNG_UST_STREAM
:
954 /* Receive shm_fd, wakeup_fd */
955 ret
= ustcomm_recv_stream_from_sessiond(sock
,
958 &args
.stream
.wakeup_fd
);
964 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
965 (unsigned long) &lum
->u
,
971 case LTTNG_UST_CONTEXT
:
972 switch (lum
->u
.context
.ctx
) {
973 case LTTNG_UST_CONTEXT_APP_CONTEXT
:
976 size_t ctxlen
, recvlen
;
978 ctxlen
= strlen("$app.") + lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1
979 + strlen(":") + lum
->u
.context
.u
.app_ctx
.ctx_name_len
;
980 if (ctxlen
>= LTTNG_UST_SYM_NAME_LEN
) {
981 ERR("Application context string length size is too large: %zu bytes",
986 strcpy(ctxstr
, "$app.");
987 p
= &ctxstr
[strlen("$app.")];
988 recvlen
= ctxlen
- strlen("$app.");
989 len
= ustcomm_recv_unix_sock(sock
, p
, recvlen
);
991 case 0: /* orderly shutdown */
995 if (len
== recvlen
) {
996 DBG("app context data received");
998 } else if (len
< 0) {
999 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1000 if (len
== -ECONNRESET
) {
1001 ERR("%s remote end closed connection", sock_info
->name
);
1008 DBG("incorrect app context data message size: %zd", len
);
1013 /* Put : between provider and ctxname. */
1014 p
[lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1] = ':';
1015 args
.app_context
.ctxname
= ctxstr
;
1022 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1023 (unsigned long) &lum
->u
,
1031 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1032 (unsigned long) &lum
->u
,
1039 lur
.handle
= lum
->handle
;
1043 lur
.ret_code
= LTTNG_UST_OK
;
1046 * Use -LTTNG_UST_ERR as wildcard for UST internal
1047 * error that are not caused by the transport, except if
1048 * we already have a more precise error message to
1051 if (ret
> -LTTNG_UST_ERR
) {
1052 /* Translate code to UST error. */
1055 lur
.ret_code
= -LTTNG_UST_ERR_EXIST
;
1058 lur
.ret_code
= -LTTNG_UST_ERR_INVAL
;
1061 lur
.ret_code
= -LTTNG_UST_ERR_NOENT
;
1064 lur
.ret_code
= -LTTNG_UST_ERR_PERM
;
1067 lur
.ret_code
= -LTTNG_UST_ERR_NOSYS
;
1070 lur
.ret_code
= -LTTNG_UST_ERR
;
1079 case LTTNG_UST_TRACER_VERSION
:
1080 lur
.u
.version
= lum
->u
.version
;
1082 case LTTNG_UST_TRACEPOINT_LIST_GET
:
1083 memcpy(&lur
.u
.tracepoint
, &lum
->u
.tracepoint
, sizeof(lur
.u
.tracepoint
));
1087 DBG("Return value: %d", lur
.ret_val
);
1092 * Performed delayed statedump operations outside of the UST
1093 * lock. We need to take the dynamic loader lock before we take
1094 * the UST lock internally within handle_pending_statedump().
1096 handle_pending_statedump(sock_info
);
1099 ret
= -LTTNG_UST_ERR_EXITING
;
1103 ret
= send_reply(sock
, &lur
);
1105 DBG("error sending reply");
1110 * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field
1113 if (lur
.ret_code
== LTTNG_UST_OK
) {
1115 case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET
:
1116 len
= ustcomm_send_unix_sock(sock
,
1117 &args
.field_list
.entry
,
1118 sizeof(args
.field_list
.entry
));
1123 if (len
!= sizeof(args
.field_list
.entry
)) {
1137 void cleanup_sock_info(struct sock_info
*sock_info
, int exiting
)
1141 if (sock_info
->root_handle
!= -1) {
1142 ret
= lttng_ust_objd_unref(sock_info
->root_handle
, 1);
1144 ERR("Error unref root handle");
1146 sock_info
->root_handle
= -1;
1148 sock_info
->registration_done
= 0;
1149 sock_info
->initial_statedump_done
= 0;
1152 * wait_shm_mmap, socket and notify socket are used by listener
1153 * threads outside of the ust lock, so we cannot tear them down
1154 * ourselves, because we cannot join on these threads. Leave
1155 * responsibility of cleaning up these resources to the OS
1161 if (sock_info
->socket
!= -1) {
1162 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1164 ERR("Error closing ust cmd socket");
1166 sock_info
->socket
= -1;
1168 if (sock_info
->notify_socket
!= -1) {
1169 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1171 ERR("Error closing ust notify socket");
1173 sock_info
->notify_socket
= -1;
1175 if (sock_info
->wait_shm_mmap
) {
1178 page_size
= LTTNG_UST_PAGE_SIZE
;
1179 if (page_size
<= 0) {
1183 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1185 ret
= munmap(sock_info
->wait_shm_mmap
, page_size
);
1187 ERR("Error unmapping wait shm");
1190 sock_info
->wait_shm_mmap
= NULL
;
1195 * Using fork to set umask in the child process (not multi-thread safe).
1196 * We deal with the shm_open vs ftruncate race (happening when the
1197 * sessiond owns the shm and does not let everybody modify it, to ensure
1198 * safety against shm_unlink) by simply letting the mmap fail and
1199 * retrying after a few seconds.
1200 * For global shm, everybody has rw access to it until the sessiond
1204 int get_wait_shm(struct sock_info
*sock_info
, size_t mmap_size
)
1206 int wait_shm_fd
, ret
;
1210 * Try to open read-only.
1212 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1213 if (wait_shm_fd
>= 0) {
1216 size_t bytes_read
= 0;
1219 * Try to read the fd. If unable to do so, try opening
1223 len
= read(wait_shm_fd
,
1224 &((char *) &tmp_read
)[bytes_read
],
1225 sizeof(tmp_read
) - bytes_read
);
1229 } while ((len
< 0 && errno
== EINTR
)
1230 || (len
> 0 && bytes_read
< sizeof(tmp_read
)));
1231 if (bytes_read
!= sizeof(tmp_read
)) {
1232 ret
= close(wait_shm_fd
);
1234 ERR("close wait_shm_fd");
1239 } else if (wait_shm_fd
< 0 && errno
!= ENOENT
) {
1241 * Real-only open did not work, and it's not because the
1242 * entry was not present. It's a failure that prohibits
1245 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1251 * If the open failed because the file did not exist, or because
1252 * the file was not truncated yet, try creating it ourself.
1254 URCU_TLS(lttng_ust_nest_count
)++;
1256 URCU_TLS(lttng_ust_nest_count
)--;
1261 * Parent: wait for child to return, in which case the
1262 * shared memory map will have been created.
1264 pid
= wait(&status
);
1265 if (pid
< 0 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0) {
1270 * Try to open read-only again after creation.
1272 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1273 if (wait_shm_fd
< 0) {
1275 * Real-only open did not work. It's a failure
1276 * that prohibits using shm.
1278 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1282 } else if (pid
== 0) {
1286 create_mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
;
1287 if (sock_info
->global
)
1288 create_mode
|= S_IROTH
| S_IWGRP
| S_IWOTH
;
1290 * We're alone in a child process, so we can modify the
1291 * process-wide umask.
1293 umask(~create_mode
);
1295 * Try creating shm (or get rw access).
1296 * We don't do an exclusive open, because we allow other
1297 * processes to create+ftruncate it concurrently.
1299 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
,
1300 O_RDWR
| O_CREAT
, create_mode
);
1301 if (wait_shm_fd
>= 0) {
1302 ret
= ftruncate(wait_shm_fd
, mmap_size
);
1304 PERROR("ftruncate");
1305 _exit(EXIT_FAILURE
);
1307 _exit(EXIT_SUCCESS
);
1310 * For local shm, we need to have rw access to accept
1311 * opening it: this means the local sessiond will be
1312 * able to wake us up. For global shm, we open it even
1313 * if rw access is not granted, because the root.root
1314 * sessiond will be able to override all rights and wake
1317 if (!sock_info
->global
&& errno
!= EACCES
) {
1318 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1319 _exit(EXIT_FAILURE
);
1322 * The shm exists, but we cannot open it RW. Report
1325 _exit(EXIT_SUCCESS
);
1330 if (wait_shm_fd
>= 0 && !sock_info
->global
) {
1331 struct stat statbuf
;
1334 * Ensure that our user is the owner of the shm file for
1335 * local shm. If we do not own the file, it means our
1336 * sessiond will not have access to wake us up (there is
1337 * probably a rogue process trying to fake our
1338 * sessiond). Fallback to polling method in this case.
1340 ret
= fstat(wait_shm_fd
, &statbuf
);
1345 if (statbuf
.st_uid
!= getuid())
1351 ret
= close(wait_shm_fd
);
1353 PERROR("Error closing fd");
1359 char *get_map_shm(struct sock_info
*sock_info
)
1362 int wait_shm_fd
, ret
;
1363 char *wait_shm_mmap
;
1365 page_size
= sysconf(_SC_PAGE_SIZE
);
1366 if (page_size
<= 0) {
1370 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1374 lttng_ust_lock_fd_tracker();
1375 wait_shm_fd
= get_wait_shm(sock_info
, page_size
);
1376 if (wait_shm_fd
< 0) {
1377 lttng_ust_unlock_fd_tracker();
1381 ret
= lttng_ust_add_fd_to_tracker(wait_shm_fd
);
1383 ret
= close(wait_shm_fd
);
1385 PERROR("Error closing fd");
1387 lttng_ust_unlock_fd_tracker();
1392 lttng_ust_unlock_fd_tracker();
1394 wait_shm_mmap
= mmap(NULL
, page_size
, PROT_READ
,
1395 MAP_SHARED
, wait_shm_fd
, 0);
1397 /* close shm fd immediately after taking the mmap reference */
1398 lttng_ust_lock_fd_tracker();
1399 ret
= close(wait_shm_fd
);
1401 lttng_ust_delete_fd_from_tracker(wait_shm_fd
);
1403 PERROR("Error closing fd");
1405 lttng_ust_unlock_fd_tracker();
1407 if (wait_shm_mmap
== MAP_FAILED
) {
1408 DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
1411 return wait_shm_mmap
;
1418 void wait_for_sessiond(struct sock_info
*sock_info
)
1420 /* Use ust_lock to check if we should quit. */
1424 if (wait_poll_fallback
) {
1429 assert(sock_info
->wait_shm_mmap
);
1431 DBG("Waiting for %s apps sessiond", sock_info
->name
);
1432 /* Wait for futex wakeup */
1433 if (uatomic_read((int32_t *) sock_info
->wait_shm_mmap
))
1436 while (futex_async((int32_t *) sock_info
->wait_shm_mmap
,
1437 FUTEX_WAIT
, 0, NULL
, NULL
, 0)) {
1440 /* Value already changed. */
1443 /* Retry if interrupted by signal. */
1444 break; /* Get out of switch. */
1446 wait_poll_fallback
= 1;
1448 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
1449 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
1450 "Please upgrade your kernel "
1451 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
1452 "mainline). LTTng-UST will use polling mode fallback.");
1471 * This thread does not allocate any resource, except within
1472 * handle_message, within mutex protection. This mutex protects against
1474 * The other moment it allocates resources is at socket connection, which
1475 * is also protected by the mutex.
1478 void *ust_listener_thread(void *arg
)
1480 struct sock_info
*sock_info
= arg
;
1481 int sock
, ret
, prev_connect_failed
= 0, has_waited
= 0, fd
;
1484 lttng_ust_fixup_tls();
1486 * If available, add '-ust' to the end of this thread's
1489 ret
= lttng_ust_setustprocname();
1491 ERR("Unable to set UST process name");
1494 /* Restart trying to connect to the session daemon */
1496 if (prev_connect_failed
) {
1497 /* Wait for sessiond availability with pipe */
1498 wait_for_sessiond(sock_info
);
1502 * Sleep for 5 seconds before retrying after a
1503 * sequence of failure / wait / failure. This
1504 * deals with a killed or broken session daemon.
1510 prev_connect_failed
= 0;
1517 if (sock_info
->socket
!= -1) {
1518 /* FD tracker is updated by ustcomm_close_unix_sock() */
1519 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1521 ERR("Error closing %s ust cmd socket",
1524 sock_info
->socket
= -1;
1526 if (sock_info
->notify_socket
!= -1) {
1527 /* FD tracker is updated by ustcomm_close_unix_sock() */
1528 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1530 ERR("Error closing %s ust notify socket",
1533 sock_info
->notify_socket
= -1;
1538 * Register. We need to perform both connect and sending
1539 * registration message before doing the next connect otherwise
1540 * we may reach unix socket connect queue max limits and block
1541 * on the 2nd connect while the session daemon is awaiting the
1542 * first connect registration message.
1544 /* Connect cmd socket */
1545 lttng_ust_lock_fd_tracker();
1546 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1547 get_connect_sock_timeout());
1549 lttng_ust_unlock_fd_tracker();
1550 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1551 prev_connect_failed
= 1;
1554 * If we cannot find the sessiond daemon, don't delay
1555 * constructor execution.
1557 ret
= handle_register_failed(sock_info
);
1563 ret
= lttng_ust_add_fd_to_tracker(fd
);
1567 PERROR("close on sock_info->socket");
1570 lttng_ust_unlock_fd_tracker();
1575 sock_info
->socket
= ret
;
1576 lttng_ust_unlock_fd_tracker();
1580 * Unlock/relock ust lock because connect is blocking (with
1581 * timeout). Don't delay constructors on the ust lock for too
1589 * Create only one root handle per listener thread for the whole
1590 * process lifetime, so we ensure we get ID which is statically
1591 * assigned to the root handle.
1593 if (sock_info
->root_handle
== -1) {
1594 ret
= lttng_abi_create_root_handle();
1596 ERR("Error creating root handle");
1599 sock_info
->root_handle
= ret
;
1602 ret
= register_to_sessiond(sock_info
->socket
, USTCTL_SOCKET_CMD
);
1604 ERR("Error registering to %s ust cmd socket",
1606 prev_connect_failed
= 1;
1608 * If we cannot register to the sessiond daemon, don't
1609 * delay constructor execution.
1611 ret
= handle_register_failed(sock_info
);
1619 * Unlock/relock ust lock because connect is blocking (with
1620 * timeout). Don't delay constructors on the ust lock for too
1627 /* Connect notify socket */
1628 lttng_ust_lock_fd_tracker();
1629 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1630 get_connect_sock_timeout());
1632 lttng_ust_unlock_fd_tracker();
1633 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1634 prev_connect_failed
= 1;
1637 * If we cannot find the sessiond daemon, don't delay
1638 * constructor execution.
1640 ret
= handle_register_failed(sock_info
);
1647 ret
= lttng_ust_add_fd_to_tracker(fd
);
1651 PERROR("close on sock_info->notify_socket");
1654 lttng_ust_unlock_fd_tracker();
1659 sock_info
->notify_socket
= ret
;
1660 lttng_ust_unlock_fd_tracker();
1664 * Unlock/relock ust lock because connect is blocking (with
1665 * timeout). Don't delay constructors on the ust lock for too
1672 timeout
= get_notify_sock_timeout();
1675 * Give at least 10ms to sessiond to reply to
1680 ret
= ustcomm_setsockopt_rcv_timeout(sock_info
->notify_socket
,
1683 WARN("Error setting socket receive timeout");
1685 ret
= ustcomm_setsockopt_snd_timeout(sock_info
->notify_socket
,
1688 WARN("Error setting socket send timeout");
1690 } else if (timeout
< -1) {
1691 WARN("Unsupported timeout value %ld", timeout
);
1694 ret
= register_to_sessiond(sock_info
->notify_socket
,
1695 USTCTL_SOCKET_NOTIFY
);
1697 ERR("Error registering to %s ust notify socket",
1699 prev_connect_failed
= 1;
1701 * If we cannot register to the sessiond daemon, don't
1702 * delay constructor execution.
1704 ret
= handle_register_failed(sock_info
);
1709 sock
= sock_info
->socket
;
1715 struct ustcomm_ust_msg lum
;
1717 len
= ustcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
1719 case 0: /* orderly shutdown */
1720 DBG("%s lttng-sessiond has performed an orderly shutdown", sock_info
->name
);
1725 * Either sessiond has shutdown or refused us by closing the socket.
1726 * In either case, we don't want to delay construction execution,
1727 * and we need to wait before retry.
1729 prev_connect_failed
= 1;
1731 * If we cannot register to the sessiond daemon, don't
1732 * delay constructor execution.
1734 ret
= handle_register_failed(sock_info
);
1739 print_cmd(lum
.cmd
, lum
.handle
);
1740 ret
= handle_message(sock_info
, sock
, &lum
);
1742 ERR("Error handling message for %s socket",
1745 * Close socket if protocol error is
1753 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1755 DBG("incorrect message size (%s socket): %zd", sock_info
->name
, len
);
1757 if (len
== -ECONNRESET
) {
1758 DBG("%s remote end closed connection", sock_info
->name
);
1769 /* Cleanup socket handles before trying to reconnect */
1770 lttng_ust_objd_table_owner_cleanup(sock_info
);
1772 goto restart
; /* try to reconnect */
1777 pthread_mutex_lock(&ust_exit_mutex
);
1778 sock_info
->thread_active
= 0;
1779 pthread_mutex_unlock(&ust_exit_mutex
);
1784 * Weak symbol to call when the ust malloc wrapper is not loaded.
1786 __attribute__((weak
))
1787 void lttng_ust_malloc_wrapper_init(void)
1792 * sessiond monitoring thread: monitor presence of global and per-user
1793 * sessiond by polling the application common named pipe.
1795 void __attribute__((constructor
)) lttng_ust_init(void)
1797 struct timespec constructor_timeout
;
1798 sigset_t sig_all_blocked
, orig_parent_mask
;
1799 pthread_attr_t thread_attr
;
1804 if (uatomic_xchg(&initialized
, 1) == 1)
1808 * Fixup interdependency between TLS fixup mutex (which happens
1809 * to be the dynamic linker mutex) and ust_lock, taken within
1812 lttng_ust_fixup_tls();
1814 lttng_ust_loaded
= 1;
1817 * We need to ensure that the liblttng-ust library is not unloaded to avoid
1818 * the unloading of code used by the ust_listener_threads as we can not
1819 * reliably know when they exited. To do that, manually load
1820 * liblttng-ust.so to increment the dynamic loader's internal refcount for
1821 * this library so it never becomes zero, thus never gets unloaded from the
1822 * address space of the process. Since we are already running in the
1823 * constructor of the LTTNG_UST_LIB_SO_NAME library, calling dlopen will
1824 * simply increment the refcount and no additionnal work is needed by the
1825 * dynamic loader as the shared library is already loaded in the address
1826 * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
1827 * unloading of the UST library if its refcount becomes zero (which should
1828 * never happen). Do the return value check but discard the handle at the
1829 * end of the function as it's not needed.
1831 handle
= dlopen(LTTNG_UST_LIB_SO_NAME
, RTLD_LAZY
| RTLD_NODELETE
);
1833 ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SO_NAME
);
1837 * We want precise control over the order in which we construct
1838 * our sub-libraries vs starting to receive commands from
1839 * sessiond (otherwise leading to errors when trying to create
1840 * sessiond before the init functions are completed).
1843 lttng_ust_getenv_init(); /* Needs init_usterr() to be completed. */
1845 lttng_ust_init_fd_tracker();
1846 lttng_ust_clock_init();
1847 lttng_ust_getcpu_init();
1848 lttng_ust_statedump_init();
1849 lttng_ring_buffer_metadata_client_init();
1850 lttng_ring_buffer_client_overwrite_init();
1851 lttng_ring_buffer_client_overwrite_rt_init();
1852 lttng_ring_buffer_client_discard_init();
1853 lttng_ring_buffer_client_discard_rt_init();
1854 lttng_perf_counter_init();
1856 * Invoke ust malloc wrapper init before starting other threads.
1858 lttng_ust_malloc_wrapper_init();
1860 timeout_mode
= get_constructor_timeout(&constructor_timeout
);
1862 get_allow_blocking();
1864 ret
= sem_init(&constructor_wait
, 0, 0);
1869 ret
= setup_global_apps();
1871 assert(global_apps
.allowed
== 0);
1872 DBG("global apps setup returned %d", ret
);
1875 ret
= setup_local_apps();
1877 assert(local_apps
.allowed
== 0);
1878 DBG("local apps setup returned %d", ret
);
1881 /* A new thread created by pthread_create inherits the signal mask
1882 * from the parent. To avoid any signal being received by the
1883 * listener thread, we block all signals temporarily in the parent,
1884 * while we create the listener thread.
1886 sigfillset(&sig_all_blocked
);
1887 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_parent_mask
);
1889 ERR("pthread_sigmask: %s", strerror(ret
));
1892 ret
= pthread_attr_init(&thread_attr
);
1894 ERR("pthread_attr_init: %s", strerror(ret
));
1896 ret
= pthread_attr_setdetachstate(&thread_attr
, PTHREAD_CREATE_DETACHED
);
1898 ERR("pthread_attr_setdetachstate: %s", strerror(ret
));
1901 if (global_apps
.allowed
) {
1902 pthread_mutex_lock(&ust_exit_mutex
);
1903 ret
= pthread_create(&global_apps
.ust_listener
, &thread_attr
,
1904 ust_listener_thread
, &global_apps
);
1906 ERR("pthread_create global: %s", strerror(ret
));
1908 global_apps
.thread_active
= 1;
1909 pthread_mutex_unlock(&ust_exit_mutex
);
1911 handle_register_done(&global_apps
);
1914 if (local_apps
.allowed
) {
1915 pthread_mutex_lock(&ust_exit_mutex
);
1916 ret
= pthread_create(&local_apps
.ust_listener
, &thread_attr
,
1917 ust_listener_thread
, &local_apps
);
1919 ERR("pthread_create local: %s", strerror(ret
));
1921 local_apps
.thread_active
= 1;
1922 pthread_mutex_unlock(&ust_exit_mutex
);
1924 handle_register_done(&local_apps
);
1926 ret
= pthread_attr_destroy(&thread_attr
);
1928 ERR("pthread_attr_destroy: %s", strerror(ret
));
1931 /* Restore original signal mask in parent */
1932 ret
= pthread_sigmask(SIG_SETMASK
, &orig_parent_mask
, NULL
);
1934 ERR("pthread_sigmask: %s", strerror(ret
));
1937 switch (timeout_mode
) {
1938 case 1: /* timeout wait */
1940 ret
= sem_timedwait(&constructor_wait
,
1941 &constructor_timeout
);
1942 } while (ret
< 0 && errno
== EINTR
);
1946 ERR("Timed out waiting for lttng-sessiond");
1949 PERROR("sem_timedwait");
1952 ERR("Unexpected error \"%s\" returned by sem_timedwait",
1957 case -1:/* wait forever */
1959 ret
= sem_wait(&constructor_wait
);
1960 } while (ret
< 0 && errno
== EINTR
);
1967 ERR("Unexpected error \"%s\" returned by sem_wait",
1972 case 0: /* no timeout */
1978 void lttng_ust_cleanup(int exiting
)
1980 cleanup_sock_info(&global_apps
, exiting
);
1981 cleanup_sock_info(&local_apps
, exiting
);
1982 local_apps
.allowed
= 0;
1983 global_apps
.allowed
= 0;
1985 * The teardown in this function all affect data structures
1986 * accessed under the UST lock by the listener thread. This
1987 * lock, along with the lttng_ust_comm_should_quit flag, ensure
1988 * that none of these threads are accessing this data at this
1991 lttng_ust_abi_exit();
1992 lttng_ust_events_exit();
1993 lttng_perf_counter_exit();
1994 lttng_ring_buffer_client_discard_rt_exit();
1995 lttng_ring_buffer_client_discard_exit();
1996 lttng_ring_buffer_client_overwrite_rt_exit();
1997 lttng_ring_buffer_client_overwrite_exit();
1998 lttng_ring_buffer_metadata_client_exit();
1999 lttng_ust_statedump_destroy();
2002 /* Reinitialize values for fork */
2003 sem_count
= sem_count_initial_value
;
2004 lttng_ust_comm_should_quit
= 0;
2009 void __attribute__((destructor
)) lttng_ust_exit(void)
2014 * Using pthread_cancel here because:
2015 * A) we don't want to hang application teardown.
2016 * B) the thread is not allocating any resource.
2020 * Require the communication thread to quit. Synchronize with
2021 * mutexes to ensure it is not in a mutex critical section when
2022 * pthread_cancel is later called.
2025 lttng_ust_comm_should_quit
= 1;
2028 pthread_mutex_lock(&ust_exit_mutex
);
2029 /* cancel threads */
2030 if (global_apps
.thread_active
) {
2031 ret
= pthread_cancel(global_apps
.ust_listener
);
2033 ERR("Error cancelling global ust listener thread: %s",
2036 global_apps
.thread_active
= 0;
2039 if (local_apps
.thread_active
) {
2040 ret
= pthread_cancel(local_apps
.ust_listener
);
2042 ERR("Error cancelling local ust listener thread: %s",
2045 local_apps
.thread_active
= 0;
2048 pthread_mutex_unlock(&ust_exit_mutex
);
2051 * Do NOT join threads: use of sys_futex makes it impossible to
2052 * join the threads without using async-cancel, but async-cancel
2053 * is delivered by a signal, which could hit the target thread
2054 * anywhere in its code path, including while the ust_lock() is
2055 * held, causing a deadlock for the other thread. Let the OS
2056 * cleanup the threads if there are stalled in a syscall.
2058 lttng_ust_cleanup(1);
2062 void ust_context_ns_reset(void)
2064 lttng_context_pid_ns_reset();
2065 lttng_context_cgroup_ns_reset();
2066 lttng_context_ipc_ns_reset();
2067 lttng_context_mnt_ns_reset();
2068 lttng_context_net_ns_reset();
2069 lttng_context_user_ns_reset();
2070 lttng_context_time_ns_reset();
2071 lttng_context_uts_ns_reset();
2075 void ust_context_vuids_reset(void)
2077 lttng_context_vuid_reset();
2078 lttng_context_veuid_reset();
2079 lttng_context_vsuid_reset();
2083 void ust_context_vgids_reset(void)
2085 lttng_context_vgid_reset();
2086 lttng_context_vegid_reset();
2087 lttng_context_vsgid_reset();
2091 * We exclude the worker threads across fork and clone (except
2092 * CLONE_VM), because these system calls only keep the forking thread
2093 * running in the child. Therefore, we don't want to call fork or clone
2094 * in the middle of an tracepoint or ust tracing state modification.
2095 * Holding this mutex protects these structures across fork and clone.
2097 void ust_before_fork(sigset_t
*save_sigset
)
2100 * Disable signals. This is to avoid that the child intervenes
2101 * before it is properly setup for tracing. It is safer to
2102 * disable all signals, because then we know we are not breaking
2103 * anything by restoring the original mask.
2108 /* Fixup lttng-ust TLS. */
2109 lttng_ust_fixup_tls();
2111 if (URCU_TLS(lttng_ust_nest_count
))
2113 /* Disable signals */
2114 sigfillset(&all_sigs
);
2115 ret
= sigprocmask(SIG_BLOCK
, &all_sigs
, save_sigset
);
2117 PERROR("sigprocmask");
2120 pthread_mutex_lock(&ust_fork_mutex
);
2123 urcu_bp_before_fork();
2124 lttng_ust_lock_fd_tracker();
2128 static void ust_after_fork_common(sigset_t
*restore_sigset
)
2132 DBG("process %d", getpid());
2133 lttng_perf_unlock();
2134 lttng_ust_unlock_fd_tracker();
2137 pthread_mutex_unlock(&ust_fork_mutex
);
2139 /* Restore signals */
2140 ret
= sigprocmask(SIG_SETMASK
, restore_sigset
, NULL
);
2142 PERROR("sigprocmask");
2146 void ust_after_fork_parent(sigset_t
*restore_sigset
)
2148 if (URCU_TLS(lttng_ust_nest_count
))
2150 DBG("process %d", getpid());
2151 urcu_bp_after_fork_parent();
2152 /* Release mutexes and reenable signals */
2153 ust_after_fork_common(restore_sigset
);
2157 * After fork, in the child, we need to cleanup all the leftover state,
2158 * except the worker thread which already magically disappeared thanks
2159 * to the weird Linux fork semantics. After tyding up, we call
2160 * lttng_ust_init() again to start over as a new PID.
2162 * This is meant for forks() that have tracing in the child between the
2163 * fork and following exec call (if there is any).
2165 void ust_after_fork_child(sigset_t
*restore_sigset
)
2167 if (URCU_TLS(lttng_ust_nest_count
))
2169 lttng_context_vpid_reset();
2170 lttng_context_vtid_reset();
2171 lttng_context_procname_reset();
2172 ust_context_ns_reset();
2173 ust_context_vuids_reset();
2174 ust_context_vgids_reset();
2175 DBG("process %d", getpid());
2176 /* Release urcu mutexes */
2177 urcu_bp_after_fork_child();
2178 lttng_ust_cleanup(0);
2179 /* Release mutexes and reenable signals */
2180 ust_after_fork_common(restore_sigset
);
2184 void ust_after_setns(void)
2186 ust_context_ns_reset();
2187 ust_context_vuids_reset();
2188 ust_context_vgids_reset();
2191 void ust_after_unshare(void)
2193 ust_context_ns_reset();
2194 ust_context_vuids_reset();
2195 ust_context_vgids_reset();
2198 void ust_after_setuid(void)
2200 ust_context_vuids_reset();
2203 void ust_after_seteuid(void)
2205 ust_context_vuids_reset();
2208 void ust_after_setreuid(void)
2210 ust_context_vuids_reset();
2213 void ust_after_setresuid(void)
2215 ust_context_vuids_reset();
2218 void ust_after_setgid(void)
2220 ust_context_vgids_reset();
2223 void ust_after_setegid(void)
2225 ust_context_vgids_reset();
2228 void ust_after_setregid(void)
2230 ust_context_vgids_reset();
2233 void ust_after_setresgid(void)
2235 ust_context_vgids_reset();
2238 void lttng_ust_sockinfo_session_enabled(void *owner
)
2240 struct sock_info
*sock_info
= owner
;
2241 sock_info
->statedump_pending
= 1;