2 * SPDX-License-Identifier: LGPL-2.1-only
4 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
5 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
11 #include <sys/types.h>
12 #include <sys/socket.h>
15 #include <sys/types.h>
22 #include <semaphore.h>
27 #include <urcu/uatomic.h>
29 #include <urcu/compiler.h>
30 #include <lttng/urcu/urcu-ust.h>
32 #include <lttng/ust-events.h>
33 #include <lttng/ust-abi.h>
34 #include <lttng/ust.h>
35 #include <lttng/ust-error.h>
36 #include <lttng/ust-ctl.h>
37 #include <lttng/ust-libc-wrapper.h>
38 #include <urcu/tls-compat.h>
41 #include <usterr-signal-safe.h>
42 #include <ust-helper.h>
43 #include "tracepoint-internal.h"
44 #include "lttng-tracer-core.h"
46 #include "../libringbuffer/rb-init.h"
47 #include "lttng-ust-statedump.h"
49 #include "../libringbuffer/getcpu.h"
51 #include "ust-events-internal.h"
52 #include "context-internal.h"
53 #include "ust-compat.h"
55 /* Concatenate lttng ust shared library name with its major version number. */
56 #define LTTNG_UST_LIB_SO_NAME "liblttng-ust.so." __ust_stringify(CONFIG_LTTNG_UST_LIBRARY_VERSION_MAJOR)
59 * Has lttng ust comm constructor been called ?
61 static int initialized
;
64 * The ust_lock/ust_unlock lock is used as a communication thread mutex.
65 * Held when handling a command, also held by fork() to deal with
66 * removal of threads, and by exit path.
68 * The UST lock is the centralized mutex across UST tracing control and
71 * ust_exit_mutex must never nest in ust_mutex.
73 * ust_fork_mutex must never nest in ust_mutex.
75 * ust_mutex_nest is a per-thread nesting counter, allowing the perf
76 * counter lazy initialization called by events within the statedump,
77 * which traces while the ust_mutex is held.
79 * ust_lock nests within the dynamic loader lock (within glibc) because
80 * it is taken within the library constructor.
82 * The ust fd tracker lock nests within the ust_mutex.
84 static pthread_mutex_t ust_mutex
= PTHREAD_MUTEX_INITIALIZER
;
86 /* Allow nesting the ust_mutex within the same thread. */
87 static DEFINE_URCU_TLS(int, ust_mutex_nest
);
90 * ust_exit_mutex protects thread_active variable wrt thread exit. It
91 * cannot be done by ust_mutex because pthread_cancel(), which takes an
92 * internal libc lock, cannot nest within ust_mutex.
94 * It never nests within a ust_mutex.
96 static pthread_mutex_t ust_exit_mutex
= PTHREAD_MUTEX_INITIALIZER
;
99 * ust_fork_mutex protects base address statedump tracing against forks. It
100 * prevents the dynamic loader lock to be taken (by base address statedump
101 * tracing) while a fork is happening, thus preventing deadlock issues with
102 * the dynamic loader lock.
104 static pthread_mutex_t ust_fork_mutex
= PTHREAD_MUTEX_INITIALIZER
;
106 /* Should the ust comm thread quit ? */
107 static int lttng_ust_comm_should_quit
;
110 * This variable can be tested by applications to check whether
111 * lttng-ust is loaded. They simply have to define their own
112 * "lttng_ust_loaded" weak symbol, and test it. It is set to 1 by the
113 * library constructor.
115 int lttng_ust_loaded
__attribute__((weak
));
118 * Return 0 on success, -1 if should quit.
119 * The lock is taken in both cases.
124 sigset_t sig_all_blocked
, orig_mask
;
127 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
129 ERR("pthread_setcancelstate: %s", strerror(ret
));
131 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
132 ERR("pthread_setcancelstate: unexpected oldstate");
134 sigfillset(&sig_all_blocked
);
135 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
137 ERR("pthread_sigmask: %s", strerror(ret
));
139 if (!URCU_TLS(ust_mutex_nest
)++)
140 pthread_mutex_lock(&ust_mutex
);
141 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
143 ERR("pthread_sigmask: %s", strerror(ret
));
145 if (lttng_ust_comm_should_quit
) {
153 * ust_lock_nocheck() can be used in constructors/destructors, because
154 * they are already nested within the dynamic loader lock, and therefore
155 * have exclusive access against execution of liblttng-ust destructor.
158 void ust_lock_nocheck(void)
160 sigset_t sig_all_blocked
, orig_mask
;
163 ret
= pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &oldstate
);
165 ERR("pthread_setcancelstate: %s", strerror(ret
));
167 if (oldstate
!= PTHREAD_CANCEL_ENABLE
) {
168 ERR("pthread_setcancelstate: unexpected oldstate");
170 sigfillset(&sig_all_blocked
);
171 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
173 ERR("pthread_sigmask: %s", strerror(ret
));
175 if (!URCU_TLS(ust_mutex_nest
)++)
176 pthread_mutex_lock(&ust_mutex
);
177 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
179 ERR("pthread_sigmask: %s", strerror(ret
));
186 void ust_unlock(void)
188 sigset_t sig_all_blocked
, orig_mask
;
191 sigfillset(&sig_all_blocked
);
192 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_mask
);
194 ERR("pthread_sigmask: %s", strerror(ret
));
196 if (!--URCU_TLS(ust_mutex_nest
))
197 pthread_mutex_unlock(&ust_mutex
);
198 ret
= pthread_sigmask(SIG_SETMASK
, &orig_mask
, NULL
);
200 ERR("pthread_sigmask: %s", strerror(ret
));
202 ret
= pthread_setcancelstate(PTHREAD_CANCEL_ENABLE
, &oldstate
);
204 ERR("pthread_setcancelstate: %s", strerror(ret
));
206 if (oldstate
!= PTHREAD_CANCEL_DISABLE
) {
207 ERR("pthread_setcancelstate: unexpected oldstate");
212 * Wait for either of these before continuing to the main
214 * - the register_done message from sessiond daemon
215 * (will let the sessiond daemon enable sessions before main
217 * - sessiond daemon is not reachable.
218 * - timeout (ensuring applications are resilient to session
221 static sem_t constructor_wait
;
223 * Doing this for both the global and local sessiond.
226 sem_count_initial_value
= 4,
229 static int sem_count
= sem_count_initial_value
;
232 * Counting nesting within lttng-ust. Used to ensure that calling fork()
233 * from liblttng-ust does not execute the pre/post fork handlers.
235 static DEFINE_URCU_TLS(int, lttng_ust_nest_count
);
238 * Info about socket and associated listener thread.
242 pthread_t ust_listener
; /* listener thread */
244 int registration_done
;
249 char sock_path
[PATH_MAX
];
253 char wait_shm_path
[PATH_MAX
];
255 /* Keep track of lazy state dump not performed yet. */
256 int statedump_pending
;
257 int initial_statedump_done
;
258 /* Keep procname for statedump */
259 char procname
[LTTNG_UST_ABI_PROCNAME_LEN
];
262 /* Socket from app (connect) to session daemon (listen) for communication */
263 struct sock_info global_apps
= {
268 .registration_done
= 0,
272 .sock_path
= LTTNG_DEFAULT_RUNDIR
"/" LTTNG_UST_SOCK_FILENAME
,
276 .wait_shm_path
= "/" LTTNG_UST_WAIT_FILENAME
,
278 .statedump_pending
= 0,
279 .initial_statedump_done
= 0,
283 /* TODO: allow global_apps_sock_path override */
285 struct sock_info local_apps
= {
289 .registration_done
= 0,
290 .allowed
= 0, /* Check setuid bit first */
296 .statedump_pending
= 0,
297 .initial_statedump_done
= 0,
301 static int wait_poll_fallback
;
303 static const char *cmd_name_mapping
[] = {
304 [ LTTNG_UST_ABI_RELEASE
] = "Release",
305 [ LTTNG_UST_ABI_SESSION
] = "Create Session",
306 [ LTTNG_UST_ABI_TRACER_VERSION
] = "Get Tracer Version",
308 [ LTTNG_UST_ABI_TRACEPOINT_LIST
] = "Create Tracepoint List",
309 [ LTTNG_UST_ABI_WAIT_QUIESCENT
] = "Wait for Quiescent State",
310 [ LTTNG_UST_ABI_REGISTER_DONE
] = "Registration Done",
311 [ LTTNG_UST_ABI_TRACEPOINT_FIELD_LIST
] = "Create Tracepoint Field List",
313 [ LTTNG_UST_ABI_EVENT_NOTIFIER_GROUP_CREATE
] = "Create event notifier group",
315 /* Session FD commands */
316 [ LTTNG_UST_ABI_CHANNEL
] = "Create Channel",
317 [ LTTNG_UST_ABI_SESSION_START
] = "Start Session",
318 [ LTTNG_UST_ABI_SESSION_STOP
] = "Stop Session",
320 /* Channel FD commands */
321 [ LTTNG_UST_ABI_STREAM
] = "Create Stream",
322 [ LTTNG_UST_ABI_EVENT
] = "Create Event",
324 /* Event and Channel FD commands */
325 [ LTTNG_UST_ABI_CONTEXT
] = "Create Context",
326 [ LTTNG_UST_ABI_FLUSH_BUFFER
] = "Flush Buffer",
328 /* Event, Channel and Session commands */
329 [ LTTNG_UST_ABI_ENABLE
] = "Enable",
330 [ LTTNG_UST_ABI_DISABLE
] = "Disable",
332 /* Tracepoint list commands */
333 [ LTTNG_UST_ABI_TRACEPOINT_LIST_GET
] = "List Next Tracepoint",
334 [ LTTNG_UST_ABI_TRACEPOINT_FIELD_LIST_GET
] = "List Next Tracepoint Field",
336 /* Event FD commands */
337 [ LTTNG_UST_ABI_FILTER
] = "Create Filter",
338 [ LTTNG_UST_ABI_EXCLUSION
] = "Add exclusions to event",
340 /* Event notifier group commands */
341 [ LTTNG_UST_ABI_EVENT_NOTIFIER_CREATE
] = "Create event notifier",
343 /* Session and event notifier group commands */
344 [ LTTNG_UST_ABI_COUNTER
] = "Create Counter",
346 /* Counter commands */
347 [ LTTNG_UST_ABI_COUNTER_GLOBAL
] = "Create Counter Global",
348 [ LTTNG_UST_ABI_COUNTER_CPU
] = "Create Counter CPU",
351 static const char *str_timeout
;
352 static int got_timeout_env
;
354 extern void lttng_ring_buffer_client_overwrite_init(void);
355 extern void lttng_ring_buffer_client_overwrite_rt_init(void);
356 extern void lttng_ring_buffer_client_discard_init(void);
357 extern void lttng_ring_buffer_client_discard_rt_init(void);
358 extern void lttng_ring_buffer_metadata_client_init(void);
359 extern void lttng_ring_buffer_client_overwrite_exit(void);
360 extern void lttng_ring_buffer_client_overwrite_rt_exit(void);
361 extern void lttng_ring_buffer_client_discard_exit(void);
362 extern void lttng_ring_buffer_client_discard_rt_exit(void);
363 extern void lttng_ring_buffer_metadata_client_exit(void);
365 __attribute__((visibility("hidden")))
366 extern void lttng_counter_client_percpu_32_modular_init(void);
368 __attribute__((visibility("hidden")))
369 extern void lttng_counter_client_percpu_32_modular_exit(void);
371 __attribute__((visibility("hidden")))
372 extern void lttng_counter_client_percpu_64_modular_init(void);
374 __attribute__((visibility("hidden")))
375 extern void lttng_counter_client_percpu_64_modular_exit(void);
377 static char *get_map_shm(struct sock_info
*sock_info
);
379 ssize_t
lttng_ust_read(int fd
, void *buf
, size_t len
)
382 size_t copied
= 0, to_copy
= len
;
385 ret
= read(fd
, buf
+ copied
, to_copy
);
390 } while ((ret
> 0 && to_copy
> 0)
391 || (ret
< 0 && errno
== EINTR
));
398 * Returns the HOME directory path. Caller MUST NOT free(3) the returned
402 const char *get_lttng_home_dir(void)
406 val
= (const char *) lttng_ust_getenv("LTTNG_HOME");
410 return (const char *) lttng_ust_getenv("HOME");
414 * Force a read (imply TLS fixup for dlopen) of TLS variables.
417 void lttng_fixup_nest_count_tls(void)
419 asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count
)));
423 void lttng_fixup_ust_mutex_nest_tls(void)
425 asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest
)));
429 * Fixup lttng-ust urcu TLS.
432 void lttng_fixup_lttng_ust_urcu_tls(void)
434 (void) lttng_ust_urcu_read_ongoing();
437 void lttng_ust_fixup_tls(void)
439 lttng_fixup_lttng_ust_urcu_tls();
440 lttng_fixup_ringbuffer_tls();
441 lttng_fixup_vtid_tls();
442 lttng_fixup_nest_count_tls();
443 lttng_fixup_procname_tls();
444 lttng_fixup_ust_mutex_nest_tls();
445 lttng_ust_fixup_perf_counter_tls();
446 lttng_ust_fixup_fd_tracker_tls();
447 lttng_fixup_cgroup_ns_tls();
448 lttng_fixup_ipc_ns_tls();
449 lttng_fixup_net_ns_tls();
450 lttng_fixup_time_ns_tls();
451 lttng_fixup_uts_ns_tls();
454 int lttng_get_notify_socket(void *owner
)
456 struct sock_info
*info
= owner
;
458 return info
->notify_socket
;
462 char* lttng_ust_sockinfo_get_procname(void *owner
)
464 struct sock_info
*info
= owner
;
466 return info
->procname
;
470 void print_cmd(int cmd
, int handle
)
472 const char *cmd_name
= "Unknown";
474 if (cmd
>= 0 && cmd
< LTTNG_ARRAY_SIZE(cmd_name_mapping
)
475 && cmd_name_mapping
[cmd
]) {
476 cmd_name
= cmd_name_mapping
[cmd
];
478 DBG("Message Received \"%s\" (%d), Handle \"%s\" (%d)",
480 lttng_ust_obj_get_name(handle
), handle
);
484 int setup_global_apps(void)
487 assert(!global_apps
.wait_shm_mmap
);
489 global_apps
.wait_shm_mmap
= get_map_shm(&global_apps
);
490 if (!global_apps
.wait_shm_mmap
) {
491 WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
492 global_apps
.allowed
= 0;
497 global_apps
.allowed
= 1;
498 lttng_pthread_getname_np(global_apps
.procname
, LTTNG_UST_ABI_PROCNAME_LEN
);
503 int setup_local_apps(void)
506 const char *home_dir
;
509 assert(!local_apps
.wait_shm_mmap
);
513 * Disallow per-user tracing for setuid binaries.
515 if (uid
!= geteuid()) {
516 assert(local_apps
.allowed
== 0);
520 home_dir
= get_lttng_home_dir();
522 WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
523 assert(local_apps
.allowed
== 0);
527 local_apps
.allowed
= 1;
528 snprintf(local_apps
.sock_path
, PATH_MAX
, "%s/%s/%s",
530 LTTNG_DEFAULT_HOME_RUNDIR
,
531 LTTNG_UST_SOCK_FILENAME
);
532 snprintf(local_apps
.wait_shm_path
, PATH_MAX
, "/%s-%u",
533 LTTNG_UST_WAIT_FILENAME
,
536 local_apps
.wait_shm_mmap
= get_map_shm(&local_apps
);
537 if (!local_apps
.wait_shm_mmap
) {
538 WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
539 local_apps
.allowed
= 0;
544 lttng_pthread_getname_np(local_apps
.procname
, LTTNG_UST_ABI_PROCNAME_LEN
);
550 * Get socket timeout, in ms.
551 * -1: wait forever. 0: don't wait. >0: timeout, in ms.
554 long get_timeout(void)
556 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
558 if (!got_timeout_env
) {
559 str_timeout
= lttng_ust_getenv("LTTNG_UST_REGISTER_TIMEOUT");
563 constructor_delay_ms
= strtol(str_timeout
, NULL
, 10);
564 /* All negative values are considered as "-1". */
565 if (constructor_delay_ms
< -1)
566 constructor_delay_ms
= -1;
567 return constructor_delay_ms
;
570 /* Timeout for notify socket send and recv. */
572 long get_notify_sock_timeout(void)
574 return get_timeout();
577 /* Timeout for connecting to cmd and notify sockets. */
579 long get_connect_sock_timeout(void)
581 return get_timeout();
585 * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
588 int get_constructor_timeout(struct timespec
*constructor_timeout
)
590 long constructor_delay_ms
;
593 constructor_delay_ms
= get_timeout();
595 switch (constructor_delay_ms
) {
596 case -1:/* fall-through */
598 return constructor_delay_ms
;
604 * If we are unable to find the current time, don't wait.
606 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
611 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
612 constructor_timeout
->tv_nsec
+=
613 (constructor_delay_ms
% 1000UL) * 1000000UL;
614 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
615 constructor_timeout
->tv_sec
++;
616 constructor_timeout
->tv_nsec
-= 1000000000UL;
618 /* Timeout wait (constructor_delay_ms). */
623 void get_allow_blocking(void)
625 const char *str_allow_blocking
=
626 lttng_ust_getenv("LTTNG_UST_ALLOW_BLOCKING");
628 if (str_allow_blocking
) {
629 DBG("%s environment variable is set",
630 "LTTNG_UST_ALLOW_BLOCKING");
631 lttng_ust_ringbuffer_set_allow_blocking();
636 int register_to_sessiond(int socket
, enum ustctl_socket_type type
)
638 return ustcomm_send_reg_msg(socket
,
641 lttng_alignof(uint8_t) * CHAR_BIT
,
642 lttng_alignof(uint16_t) * CHAR_BIT
,
643 lttng_alignof(uint32_t) * CHAR_BIT
,
644 lttng_alignof(uint64_t) * CHAR_BIT
,
645 lttng_alignof(unsigned long) * CHAR_BIT
);
649 int send_reply(int sock
, struct ustcomm_ust_reply
*lur
)
653 len
= ustcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
656 DBG("message successfully sent");
659 if (len
== -ECONNRESET
) {
660 DBG("remote end closed connection");
665 DBG("incorrect message size: %zd", len
);
671 void decrement_sem_count(unsigned int count
)
675 assert(uatomic_read(&sem_count
) >= count
);
677 if (uatomic_read(&sem_count
) <= 0) {
681 ret
= uatomic_add_return(&sem_count
, -count
);
683 ret
= sem_post(&constructor_wait
);
689 int handle_register_done(struct sock_info
*sock_info
)
691 if (sock_info
->registration_done
)
693 sock_info
->registration_done
= 1;
695 decrement_sem_count(1);
696 if (!sock_info
->statedump_pending
) {
697 sock_info
->initial_statedump_done
= 1;
698 decrement_sem_count(1);
705 int handle_register_failed(struct sock_info
*sock_info
)
707 if (sock_info
->registration_done
)
709 sock_info
->registration_done
= 1;
710 sock_info
->initial_statedump_done
= 1;
712 decrement_sem_count(2);
718 * Only execute pending statedump after the constructor semaphore has
719 * been posted by the current listener thread. This means statedump will
720 * only be performed after the "registration done" command is received
721 * from this thread's session daemon.
723 * This ensures we don't run into deadlock issues with the dynamic
724 * loader mutex, which is held while the constructor is called and
725 * waiting on the constructor semaphore. All operations requiring this
726 * dynamic loader lock need to be postponed using this mechanism.
728 * In a scenario with two session daemons connected to the application,
729 * it is possible that the first listener thread which receives the
730 * registration done command issues its statedump while the dynamic
731 * loader lock is still held by the application constructor waiting on
732 * the semaphore. It will however be allowed to proceed when the
733 * second session daemon sends the registration done command to the
734 * second listener thread. This situation therefore does not produce
738 void handle_pending_statedump(struct sock_info
*sock_info
)
740 if (sock_info
->registration_done
&& sock_info
->statedump_pending
) {
741 sock_info
->statedump_pending
= 0;
742 pthread_mutex_lock(&ust_fork_mutex
);
743 lttng_handle_pending_statedump(sock_info
);
744 pthread_mutex_unlock(&ust_fork_mutex
);
746 if (!sock_info
->initial_statedump_done
) {
747 sock_info
->initial_statedump_done
= 1;
748 decrement_sem_count(1);
754 const char *bytecode_type_str(uint32_t cmd
)
757 case LTTNG_UST_ABI_CAPTURE
:
759 case LTTNG_UST_ABI_FILTER
:
767 int handle_bytecode_recv(struct sock_info
*sock_info
,
768 int sock
, struct ustcomm_ust_msg
*lum
)
770 struct lttng_ust_bytecode_node
*bytecode
= NULL
;
771 enum lttng_ust_bytecode_type type
;
772 const struct lttng_ust_abi_objd_ops
*ops
;
773 uint32_t data_size
, data_size_max
, reloc_offset
;
779 case LTTNG_UST_ABI_FILTER
:
780 type
= LTTNG_UST_BYTECODE_TYPE_FILTER
;
781 data_size
= lum
->u
.filter
.data_size
;
782 data_size_max
= LTTNG_UST_ABI_FILTER_BYTECODE_MAX_LEN
;
783 reloc_offset
= lum
->u
.filter
.reloc_offset
;
784 seqnum
= lum
->u
.filter
.seqnum
;
786 case LTTNG_UST_ABI_CAPTURE
:
787 type
= LTTNG_UST_BYTECODE_TYPE_CAPTURE
;
788 data_size
= lum
->u
.capture
.data_size
;
789 data_size_max
= LTTNG_UST_ABI_CAPTURE_BYTECODE_MAX_LEN
;
790 reloc_offset
= lum
->u
.capture
.reloc_offset
;
791 seqnum
= lum
->u
.capture
.seqnum
;
797 if (data_size
> data_size_max
) {
798 ERR("Bytecode %s data size is too large: %u bytes",
799 bytecode_type_str(lum
->cmd
), data_size
);
804 if (reloc_offset
> data_size
) {
805 ERR("Bytecode %s reloc offset %u is not within data",
806 bytecode_type_str(lum
->cmd
), reloc_offset
);
811 /* Allocate the structure AND the `data[]` field. */
812 bytecode
= zmalloc(sizeof(*bytecode
) + data_size
);
818 bytecode
->bc
.len
= data_size
;
819 bytecode
->bc
.reloc_offset
= reloc_offset
;
820 bytecode
->bc
.seqnum
= seqnum
;
821 bytecode
->type
= type
;
823 len
= ustcomm_recv_unix_sock(sock
, bytecode
->bc
.data
, bytecode
->bc
.len
);
825 case 0: /* orderly shutdown */
829 if (len
== bytecode
->bc
.len
) {
830 DBG("Bytecode %s data received",
831 bytecode_type_str(lum
->cmd
));
833 } else if (len
< 0) {
834 DBG("Receive failed from lttng-sessiond with errno %d",
836 if (len
== -ECONNRESET
) {
837 ERR("%s remote end closed connection",
845 DBG("Incorrect %s bytecode data message size: %zd",
846 bytecode_type_str(lum
->cmd
), len
);
852 ops
= lttng_ust_abi_objd_ops(lum
->handle
);
859 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
860 (unsigned long) &bytecode
,
871 int handle_message(struct sock_info
*sock_info
,
872 int sock
, struct ustcomm_ust_msg
*lum
)
875 const struct lttng_ust_abi_objd_ops
*ops
;
876 struct ustcomm_ust_reply lur
;
877 union lttng_ust_abi_args args
;
878 char ctxstr
[LTTNG_UST_ABI_SYM_NAME_LEN
]; /* App context string. */
881 memset(&lur
, 0, sizeof(lur
));
884 ret
= -LTTNG_UST_ERR_EXITING
;
888 ops
= lttng_ust_abi_objd_ops(lum
->handle
);
895 case LTTNG_UST_ABI_REGISTER_DONE
:
896 if (lum
->handle
== LTTNG_UST_ABI_ROOT_HANDLE
)
897 ret
= handle_register_done(sock_info
);
901 case LTTNG_UST_ABI_RELEASE
:
902 if (lum
->handle
== LTTNG_UST_ABI_ROOT_HANDLE
)
905 ret
= lttng_ust_abi_objd_unref(lum
->handle
, 1);
907 case LTTNG_UST_ABI_CAPTURE
:
908 case LTTNG_UST_ABI_FILTER
:
909 ret
= handle_bytecode_recv(sock_info
, sock
, lum
);
913 case LTTNG_UST_ABI_EXCLUSION
:
915 /* Receive exclusion names */
916 struct lttng_ust_excluder_node
*node
;
919 count
= lum
->u
.exclusion
.count
;
921 /* There are no names to read */
925 node
= zmalloc(sizeof(*node
) +
926 count
* LTTNG_UST_ABI_SYM_NAME_LEN
);
931 node
->excluder
.count
= count
;
932 len
= ustcomm_recv_unix_sock(sock
, node
->excluder
.names
,
933 count
* LTTNG_UST_ABI_SYM_NAME_LEN
);
935 case 0: /* orderly shutdown */
940 if (len
== count
* LTTNG_UST_ABI_SYM_NAME_LEN
) {
941 DBG("Exclusion data received");
943 } else if (len
< 0) {
944 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
945 if (len
== -ECONNRESET
) {
946 ERR("%s remote end closed connection", sock_info
->name
);
955 DBG("Incorrect exclusion data message size: %zd", len
);
962 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
963 (unsigned long) &node
,
970 case LTTNG_UST_ABI_EVENT_NOTIFIER_GROUP_CREATE
:
972 int event_notifier_notif_fd
, close_ret
;
974 len
= ustcomm_recv_event_notifier_notif_fd_from_sessiond(sock
,
975 &event_notifier_notif_fd
);
977 case 0: /* orderly shutdown */
984 DBG("Receive failed from lttng-sessiond with errno %d",
986 if (len
== -ECONNRESET
) {
987 ERR("%s remote end closed connection",
995 DBG("Incorrect event notifier fd message size: %zd",
1001 args
.event_notifier_handle
.event_notifier_notif_fd
=
1002 event_notifier_notif_fd
;
1004 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1005 (unsigned long) &lum
->u
,
1009 if (args
.event_notifier_handle
.event_notifier_notif_fd
>= 0) {
1010 lttng_ust_lock_fd_tracker();
1011 close_ret
= close(args
.event_notifier_handle
.event_notifier_notif_fd
);
1012 lttng_ust_unlock_fd_tracker();
1018 case LTTNG_UST_ABI_CHANNEL
:
1023 len
= ustcomm_recv_channel_from_sessiond(sock
,
1024 &chan_data
, lum
->u
.channel
.len
,
1027 case 0: /* orderly shutdown */
1031 if (len
== lum
->u
.channel
.len
) {
1032 DBG("channel data received");
1034 } else if (len
< 0) {
1035 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1036 if (len
== -ECONNRESET
) {
1037 ERR("%s remote end closed connection", sock_info
->name
);
1044 DBG("incorrect channel data message size: %zd", len
);
1049 args
.channel
.chan_data
= chan_data
;
1050 args
.channel
.wakeup_fd
= wakeup_fd
;
1052 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1053 (unsigned long) &lum
->u
,
1057 if (args
.channel
.wakeup_fd
>= 0) {
1060 lttng_ust_lock_fd_tracker();
1061 close_ret
= close(args
.channel
.wakeup_fd
);
1062 lttng_ust_unlock_fd_tracker();
1063 args
.channel
.wakeup_fd
= -1;
1067 free(args
.channel
.chan_data
);
1070 case LTTNG_UST_ABI_STREAM
:
1074 /* Receive shm_fd, wakeup_fd */
1075 ret
= ustcomm_recv_stream_from_sessiond(sock
,
1077 &args
.stream
.shm_fd
,
1078 &args
.stream
.wakeup_fd
);
1084 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1085 (unsigned long) &lum
->u
,
1089 if (args
.stream
.shm_fd
>= 0) {
1090 lttng_ust_lock_fd_tracker();
1091 close_ret
= close(args
.stream
.shm_fd
);
1092 lttng_ust_unlock_fd_tracker();
1093 args
.stream
.shm_fd
= -1;
1097 if (args
.stream
.wakeup_fd
>= 0) {
1098 lttng_ust_lock_fd_tracker();
1099 close_ret
= close(args
.stream
.wakeup_fd
);
1100 lttng_ust_unlock_fd_tracker();
1101 args
.stream
.wakeup_fd
= -1;
1107 case LTTNG_UST_ABI_CONTEXT
:
1108 switch (lum
->u
.context
.ctx
) {
1109 case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT
:
1112 size_t ctxlen
, recvlen
;
1114 ctxlen
= strlen("$app.") + lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1
1115 + strlen(":") + lum
->u
.context
.u
.app_ctx
.ctx_name_len
;
1116 if (ctxlen
>= LTTNG_UST_ABI_SYM_NAME_LEN
) {
1117 ERR("Application context string length size is too large: %zu bytes",
1122 strcpy(ctxstr
, "$app.");
1123 p
= &ctxstr
[strlen("$app.")];
1124 recvlen
= ctxlen
- strlen("$app.");
1125 len
= ustcomm_recv_unix_sock(sock
, p
, recvlen
);
1127 case 0: /* orderly shutdown */
1131 if (len
== recvlen
) {
1132 DBG("app context data received");
1134 } else if (len
< 0) {
1135 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1136 if (len
== -ECONNRESET
) {
1137 ERR("%s remote end closed connection", sock_info
->name
);
1144 DBG("incorrect app context data message size: %zd", len
);
1149 /* Put : between provider and ctxname. */
1150 p
[lum
->u
.context
.u
.app_ctx
.provider_name_len
- 1] = ':';
1151 args
.app_context
.ctxname
= ctxstr
;
1158 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1159 (unsigned long) &lum
->u
,
1165 case LTTNG_UST_ABI_COUNTER
:
1169 len
= ustcomm_recv_counter_from_sessiond(sock
,
1170 &counter_data
, lum
->u
.counter
.len
);
1172 case 0: /* orderly shutdown */
1176 if (len
== lum
->u
.counter
.len
) {
1177 DBG("counter data received");
1179 } else if (len
< 0) {
1180 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1181 if (len
== -ECONNRESET
) {
1182 ERR("%s remote end closed connection", sock_info
->name
);
1189 DBG("incorrect counter data message size: %zd", len
);
1194 args
.counter
.counter_data
= counter_data
;
1196 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1197 (unsigned long) &lum
->u
,
1201 free(args
.counter
.counter_data
);
1204 case LTTNG_UST_ABI_COUNTER_GLOBAL
:
1206 /* Receive shm_fd */
1207 ret
= ustcomm_recv_counter_shm_from_sessiond(sock
,
1208 &args
.counter_shm
.shm_fd
);
1214 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1215 (unsigned long) &lum
->u
,
1219 if (args
.counter_shm
.shm_fd
>= 0) {
1222 lttng_ust_lock_fd_tracker();
1223 close_ret
= close(args
.counter_shm
.shm_fd
);
1224 lttng_ust_unlock_fd_tracker();
1225 args
.counter_shm
.shm_fd
= -1;
1231 case LTTNG_UST_ABI_COUNTER_CPU
:
1233 /* Receive shm_fd */
1234 ret
= ustcomm_recv_counter_shm_from_sessiond(sock
,
1235 &args
.counter_shm
.shm_fd
);
1241 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1242 (unsigned long) &lum
->u
,
1246 if (args
.counter_shm
.shm_fd
>= 0) {
1249 lttng_ust_lock_fd_tracker();
1250 close_ret
= close(args
.counter_shm
.shm_fd
);
1251 lttng_ust_unlock_fd_tracker();
1252 args
.counter_shm
.shm_fd
= -1;
1258 case LTTNG_UST_ABI_EVENT_NOTIFIER_CREATE
:
1260 /* Receive struct lttng_ust_event_notifier */
1261 struct lttng_ust_abi_event_notifier event_notifier
;
1263 if (sizeof(event_notifier
) != lum
->u
.event_notifier
.len
) {
1264 DBG("incorrect event notifier data message size: %u", lum
->u
.event_notifier
.len
);
1268 len
= ustcomm_recv_unix_sock(sock
, &event_notifier
, sizeof(event_notifier
));
1270 case 0: /* orderly shutdown */
1274 if (len
== sizeof(event_notifier
)) {
1275 DBG("event notifier data received");
1277 } else if (len
< 0) {
1278 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
1279 if (len
== -ECONNRESET
) {
1280 ERR("%s remote end closed connection", sock_info
->name
);
1287 DBG("incorrect event notifier data message size: %zd", len
);
1293 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1294 (unsigned long) &event_notifier
,
1303 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
1304 (unsigned long) &lum
->u
,
1311 lur
.handle
= lum
->handle
;
1315 lur
.ret_code
= LTTNG_UST_OK
;
1318 * Use -LTTNG_UST_ERR as wildcard for UST internal
1319 * error that are not caused by the transport, except if
1320 * we already have a more precise error message to
1323 if (ret
> -LTTNG_UST_ERR
) {
1324 /* Translate code to UST error. */
1327 lur
.ret_code
= -LTTNG_UST_ERR_EXIST
;
1330 lur
.ret_code
= -LTTNG_UST_ERR_INVAL
;
1333 lur
.ret_code
= -LTTNG_UST_ERR_NOENT
;
1336 lur
.ret_code
= -LTTNG_UST_ERR_PERM
;
1339 lur
.ret_code
= -LTTNG_UST_ERR_NOSYS
;
1342 lur
.ret_code
= -LTTNG_UST_ERR
;
1351 case LTTNG_UST_ABI_TRACER_VERSION
:
1352 lur
.u
.version
= lum
->u
.version
;
1354 case LTTNG_UST_ABI_TRACEPOINT_LIST_GET
:
1355 memcpy(&lur
.u
.tracepoint
, &lum
->u
.tracepoint
, sizeof(lur
.u
.tracepoint
));
1359 DBG("Return value: %d", lur
.ret_val
);
1364 * Performed delayed statedump operations outside of the UST
1365 * lock. We need to take the dynamic loader lock before we take
1366 * the UST lock internally within handle_pending_statedump().
1368 handle_pending_statedump(sock_info
);
1371 ret
= -LTTNG_UST_ERR_EXITING
;
1375 ret
= send_reply(sock
, &lur
);
1377 DBG("error sending reply");
1382 * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field
1385 if (lur
.ret_code
== LTTNG_UST_OK
) {
1387 case LTTNG_UST_ABI_TRACEPOINT_FIELD_LIST_GET
:
1388 len
= ustcomm_send_unix_sock(sock
,
1389 &args
.field_list
.entry
,
1390 sizeof(args
.field_list
.entry
));
1395 if (len
!= sizeof(args
.field_list
.entry
)) {
1409 void cleanup_sock_info(struct sock_info
*sock_info
, int exiting
)
1413 if (sock_info
->root_handle
!= -1) {
1414 ret
= lttng_ust_abi_objd_unref(sock_info
->root_handle
, 1);
1416 ERR("Error unref root handle");
1418 sock_info
->root_handle
= -1;
1420 sock_info
->registration_done
= 0;
1421 sock_info
->initial_statedump_done
= 0;
1424 * wait_shm_mmap, socket and notify socket are used by listener
1425 * threads outside of the ust lock, so we cannot tear them down
1426 * ourselves, because we cannot join on these threads. Leave
1427 * responsibility of cleaning up these resources to the OS
1433 if (sock_info
->socket
!= -1) {
1434 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1436 ERR("Error closing ust cmd socket");
1438 sock_info
->socket
= -1;
1440 if (sock_info
->notify_socket
!= -1) {
1441 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1443 ERR("Error closing ust notify socket");
1445 sock_info
->notify_socket
= -1;
1447 if (sock_info
->wait_shm_mmap
) {
1450 page_size
= LTTNG_UST_PAGE_SIZE
;
1451 if (page_size
<= 0) {
1455 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1457 ret
= munmap(sock_info
->wait_shm_mmap
, page_size
);
1459 ERR("Error unmapping wait shm");
1462 sock_info
->wait_shm_mmap
= NULL
;
1467 * Using fork to set umask in the child process (not multi-thread safe).
1468 * We deal with the shm_open vs ftruncate race (happening when the
1469 * sessiond owns the shm and does not let everybody modify it, to ensure
1470 * safety against shm_unlink) by simply letting the mmap fail and
1471 * retrying after a few seconds.
1472 * For global shm, everybody has rw access to it until the sessiond
1476 int get_wait_shm(struct sock_info
*sock_info
, size_t mmap_size
)
1478 int wait_shm_fd
, ret
;
1482 * Try to open read-only.
1484 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1485 if (wait_shm_fd
>= 0) {
1488 size_t bytes_read
= 0;
1491 * Try to read the fd. If unable to do so, try opening
1495 len
= read(wait_shm_fd
,
1496 &((char *) &tmp_read
)[bytes_read
],
1497 sizeof(tmp_read
) - bytes_read
);
1501 } while ((len
< 0 && errno
== EINTR
)
1502 || (len
> 0 && bytes_read
< sizeof(tmp_read
)));
1503 if (bytes_read
!= sizeof(tmp_read
)) {
1504 ret
= close(wait_shm_fd
);
1506 ERR("close wait_shm_fd");
1511 } else if (wait_shm_fd
< 0 && errno
!= ENOENT
) {
1513 * Real-only open did not work, and it's not because the
1514 * entry was not present. It's a failure that prohibits
1517 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1523 * If the open failed because the file did not exist, or because
1524 * the file was not truncated yet, try creating it ourself.
1526 URCU_TLS(lttng_ust_nest_count
)++;
1528 URCU_TLS(lttng_ust_nest_count
)--;
1533 * Parent: wait for child to return, in which case the
1534 * shared memory map will have been created.
1536 pid
= wait(&status
);
1537 if (pid
< 0 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0) {
1542 * Try to open read-only again after creation.
1544 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
, O_RDONLY
, 0);
1545 if (wait_shm_fd
< 0) {
1547 * Real-only open did not work. It's a failure
1548 * that prohibits using shm.
1550 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1554 } else if (pid
== 0) {
1558 create_mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
;
1559 if (sock_info
->global
)
1560 create_mode
|= S_IROTH
| S_IWGRP
| S_IWOTH
;
1562 * We're alone in a child process, so we can modify the
1563 * process-wide umask.
1565 umask(~create_mode
);
1567 * Try creating shm (or get rw access).
1568 * We don't do an exclusive open, because we allow other
1569 * processes to create+ftruncate it concurrently.
1571 wait_shm_fd
= shm_open(sock_info
->wait_shm_path
,
1572 O_RDWR
| O_CREAT
, create_mode
);
1573 if (wait_shm_fd
>= 0) {
1574 ret
= ftruncate(wait_shm_fd
, mmap_size
);
1576 PERROR("ftruncate");
1577 _exit(EXIT_FAILURE
);
1579 _exit(EXIT_SUCCESS
);
1582 * For local shm, we need to have rw access to accept
1583 * opening it: this means the local sessiond will be
1584 * able to wake us up. For global shm, we open it even
1585 * if rw access is not granted, because the root.root
1586 * sessiond will be able to override all rights and wake
1589 if (!sock_info
->global
&& errno
!= EACCES
) {
1590 ERR("Error opening shm %s", sock_info
->wait_shm_path
);
1591 _exit(EXIT_FAILURE
);
1594 * The shm exists, but we cannot open it RW. Report
1597 _exit(EXIT_SUCCESS
);
1602 if (wait_shm_fd
>= 0 && !sock_info
->global
) {
1603 struct stat statbuf
;
1606 * Ensure that our user is the owner of the shm file for
1607 * local shm. If we do not own the file, it means our
1608 * sessiond will not have access to wake us up (there is
1609 * probably a rogue process trying to fake our
1610 * sessiond). Fallback to polling method in this case.
1612 ret
= fstat(wait_shm_fd
, &statbuf
);
1617 if (statbuf
.st_uid
!= getuid())
1623 ret
= close(wait_shm_fd
);
1625 PERROR("Error closing fd");
1631 char *get_map_shm(struct sock_info
*sock_info
)
1634 int wait_shm_fd
, ret
;
1635 char *wait_shm_mmap
;
1637 page_size
= sysconf(_SC_PAGE_SIZE
);
1638 if (page_size
<= 0) {
1642 PERROR("Error in sysconf(_SC_PAGE_SIZE)");
1646 lttng_ust_lock_fd_tracker();
1647 wait_shm_fd
= get_wait_shm(sock_info
, page_size
);
1648 if (wait_shm_fd
< 0) {
1649 lttng_ust_unlock_fd_tracker();
1653 ret
= lttng_ust_add_fd_to_tracker(wait_shm_fd
);
1655 ret
= close(wait_shm_fd
);
1657 PERROR("Error closing fd");
1659 lttng_ust_unlock_fd_tracker();
1664 lttng_ust_unlock_fd_tracker();
1666 wait_shm_mmap
= mmap(NULL
, page_size
, PROT_READ
,
1667 MAP_SHARED
, wait_shm_fd
, 0);
1669 /* close shm fd immediately after taking the mmap reference */
1670 lttng_ust_lock_fd_tracker();
1671 ret
= close(wait_shm_fd
);
1673 lttng_ust_delete_fd_from_tracker(wait_shm_fd
);
1675 PERROR("Error closing fd");
1677 lttng_ust_unlock_fd_tracker();
1679 if (wait_shm_mmap
== MAP_FAILED
) {
1680 DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
1683 return wait_shm_mmap
;
1690 void wait_for_sessiond(struct sock_info
*sock_info
)
1692 /* Use ust_lock to check if we should quit. */
1696 if (wait_poll_fallback
) {
1701 assert(sock_info
->wait_shm_mmap
);
1703 DBG("Waiting for %s apps sessiond", sock_info
->name
);
1704 /* Wait for futex wakeup */
1705 if (uatomic_read((int32_t *) sock_info
->wait_shm_mmap
))
1708 while (lttng_ust_futex_async((int32_t *) sock_info
->wait_shm_mmap
,
1709 FUTEX_WAIT
, 0, NULL
, NULL
, 0)) {
1712 /* Value already changed. */
1715 /* Retry if interrupted by signal. */
1716 break; /* Get out of switch. */
1718 wait_poll_fallback
= 1;
1720 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
1721 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
1722 "Please upgrade your kernel "
1723 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
1724 "mainline). LTTng-UST will use polling mode fallback.");
1725 if (ust_err_debug_enabled())
1743 * This thread does not allocate any resource, except within
1744 * handle_message, within mutex protection. This mutex protects against
1746 * The other moment it allocates resources is at socket connection, which
1747 * is also protected by the mutex.
1750 void *ust_listener_thread(void *arg
)
1752 struct sock_info
*sock_info
= arg
;
1753 int sock
, ret
, prev_connect_failed
= 0, has_waited
= 0, fd
;
1756 lttng_ust_fixup_tls();
1758 * If available, add '-ust' to the end of this thread's
1761 ret
= lttng_ust_setustprocname();
1763 ERR("Unable to set UST process name");
1766 /* Restart trying to connect to the session daemon */
1768 if (prev_connect_failed
) {
1769 /* Wait for sessiond availability with pipe */
1770 wait_for_sessiond(sock_info
);
1774 * Sleep for 5 seconds before retrying after a
1775 * sequence of failure / wait / failure. This
1776 * deals with a killed or broken session daemon.
1782 prev_connect_failed
= 0;
1789 if (sock_info
->socket
!= -1) {
1790 /* FD tracker is updated by ustcomm_close_unix_sock() */
1791 ret
= ustcomm_close_unix_sock(sock_info
->socket
);
1793 ERR("Error closing %s ust cmd socket",
1796 sock_info
->socket
= -1;
1798 if (sock_info
->notify_socket
!= -1) {
1799 /* FD tracker is updated by ustcomm_close_unix_sock() */
1800 ret
= ustcomm_close_unix_sock(sock_info
->notify_socket
);
1802 ERR("Error closing %s ust notify socket",
1805 sock_info
->notify_socket
= -1;
1810 * Register. We need to perform both connect and sending
1811 * registration message before doing the next connect otherwise
1812 * we may reach unix socket connect queue max limits and block
1813 * on the 2nd connect while the session daemon is awaiting the
1814 * first connect registration message.
1816 /* Connect cmd socket */
1817 lttng_ust_lock_fd_tracker();
1818 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1819 get_connect_sock_timeout());
1821 lttng_ust_unlock_fd_tracker();
1822 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1823 prev_connect_failed
= 1;
1826 * If we cannot find the sessiond daemon, don't delay
1827 * constructor execution.
1829 ret
= handle_register_failed(sock_info
);
1835 ret
= lttng_ust_add_fd_to_tracker(fd
);
1839 PERROR("close on sock_info->socket");
1842 lttng_ust_unlock_fd_tracker();
1847 sock_info
->socket
= ret
;
1848 lttng_ust_unlock_fd_tracker();
1852 * Unlock/relock ust lock because connect is blocking (with
1853 * timeout). Don't delay constructors on the ust lock for too
1861 * Create only one root handle per listener thread for the whole
1862 * process lifetime, so we ensure we get ID which is statically
1863 * assigned to the root handle.
1865 if (sock_info
->root_handle
== -1) {
1866 ret
= lttng_abi_create_root_handle();
1868 ERR("Error creating root handle");
1871 sock_info
->root_handle
= ret
;
1874 ret
= register_to_sessiond(sock_info
->socket
, USTCTL_SOCKET_CMD
);
1876 ERR("Error registering to %s ust cmd socket",
1878 prev_connect_failed
= 1;
1880 * If we cannot register to the sessiond daemon, don't
1881 * delay constructor execution.
1883 ret
= handle_register_failed(sock_info
);
1891 * Unlock/relock ust lock because connect is blocking (with
1892 * timeout). Don't delay constructors on the ust lock for too
1899 /* Connect notify socket */
1900 lttng_ust_lock_fd_tracker();
1901 ret
= ustcomm_connect_unix_sock(sock_info
->sock_path
,
1902 get_connect_sock_timeout());
1904 lttng_ust_unlock_fd_tracker();
1905 DBG("Info: sessiond not accepting connections to %s apps socket", sock_info
->name
);
1906 prev_connect_failed
= 1;
1909 * If we cannot find the sessiond daemon, don't delay
1910 * constructor execution.
1912 ret
= handle_register_failed(sock_info
);
1919 ret
= lttng_ust_add_fd_to_tracker(fd
);
1923 PERROR("close on sock_info->notify_socket");
1926 lttng_ust_unlock_fd_tracker();
1931 sock_info
->notify_socket
= ret
;
1932 lttng_ust_unlock_fd_tracker();
1936 * Unlock/relock ust lock because connect is blocking (with
1937 * timeout). Don't delay constructors on the ust lock for too
1944 timeout
= get_notify_sock_timeout();
1947 * Give at least 10ms to sessiond to reply to
1952 ret
= ustcomm_setsockopt_rcv_timeout(sock_info
->notify_socket
,
1955 WARN("Error setting socket receive timeout");
1957 ret
= ustcomm_setsockopt_snd_timeout(sock_info
->notify_socket
,
1960 WARN("Error setting socket send timeout");
1962 } else if (timeout
< -1) {
1963 WARN("Unsupported timeout value %ld", timeout
);
1966 ret
= register_to_sessiond(sock_info
->notify_socket
,
1967 USTCTL_SOCKET_NOTIFY
);
1969 ERR("Error registering to %s ust notify socket",
1971 prev_connect_failed
= 1;
1973 * If we cannot register to the sessiond daemon, don't
1974 * delay constructor execution.
1976 ret
= handle_register_failed(sock_info
);
1981 sock
= sock_info
->socket
;
1987 struct ustcomm_ust_msg lum
;
1989 len
= ustcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
1991 case 0: /* orderly shutdown */
1992 DBG("%s lttng-sessiond has performed an orderly shutdown", sock_info
->name
);
1997 * Either sessiond has shutdown or refused us by closing the socket.
1998 * In either case, we don't want to delay construction execution,
1999 * and we need to wait before retry.
2001 prev_connect_failed
= 1;
2003 * If we cannot register to the sessiond daemon, don't
2004 * delay constructor execution.
2006 ret
= handle_register_failed(sock_info
);
2011 print_cmd(lum
.cmd
, lum
.handle
);
2012 ret
= handle_message(sock_info
, sock
, &lum
);
2014 ERR("Error handling message for %s socket",
2017 * Close socket if protocol error is
2025 DBG("Receive failed from lttng-sessiond with errno %d", (int) -len
);
2027 DBG("incorrect message size (%s socket): %zd", sock_info
->name
, len
);
2029 if (len
== -ECONNRESET
) {
2030 DBG("%s remote end closed connection", sock_info
->name
);
2041 /* Cleanup socket handles before trying to reconnect */
2042 lttng_ust_abi_objd_table_owner_cleanup(sock_info
);
2044 goto restart
; /* try to reconnect */
2049 pthread_mutex_lock(&ust_exit_mutex
);
2050 sock_info
->thread_active
= 0;
2051 pthread_mutex_unlock(&ust_exit_mutex
);
2056 * Weak symbol to call when the ust malloc wrapper is not loaded.
2058 __attribute__((weak
))
2059 void lttng_ust_libc_wrapper_malloc_init(void)
2064 * sessiond monitoring thread: monitor presence of global and per-user
2065 * sessiond by polling the application common named pipe.
2067 void __attribute__((constructor
)) lttng_ust_init(void)
2069 struct timespec constructor_timeout
;
2070 sigset_t sig_all_blocked
, orig_parent_mask
;
2071 pthread_attr_t thread_attr
;
2076 if (uatomic_xchg(&initialized
, 1) == 1)
2080 * Fixup interdependency between TLS fixup mutex (which happens
2081 * to be the dynamic linker mutex) and ust_lock, taken within
2084 lttng_ust_fixup_tls();
2086 lttng_ust_loaded
= 1;
2089 * We need to ensure that the liblttng-ust library is not unloaded to avoid
2090 * the unloading of code used by the ust_listener_threads as we can not
2091 * reliably know when they exited. To do that, manually load
2092 * liblttng-ust.so to increment the dynamic loader's internal refcount for
2093 * this library so it never becomes zero, thus never gets unloaded from the
2094 * address space of the process. Since we are already running in the
2095 * constructor of the LTTNG_UST_LIB_SO_NAME library, calling dlopen will
2096 * simply increment the refcount and no additionnal work is needed by the
2097 * dynamic loader as the shared library is already loaded in the address
2098 * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
2099 * unloading of the UST library if its refcount becomes zero (which should
2100 * never happen). Do the return value check but discard the handle at the
2101 * end of the function as it's not needed.
2103 handle
= dlopen(LTTNG_UST_LIB_SO_NAME
, RTLD_LAZY
| RTLD_NODELETE
);
2105 ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SO_NAME
);
2109 * We want precise control over the order in which we construct
2110 * our sub-libraries vs starting to receive commands from
2111 * sessiond (otherwise leading to errors when trying to create
2112 * sessiond before the init functions are completed).
2115 lttng_ust_getenv_init(); /* Needs ust_err_init() to be completed. */
2116 lttng_ust_tp_init();
2117 lttng_ust_init_fd_tracker();
2118 lttng_ust_clock_init();
2119 lttng_ust_getcpu_init();
2120 lttng_ust_statedump_init();
2121 lttng_ring_buffer_metadata_client_init();
2122 lttng_ring_buffer_client_overwrite_init();
2123 lttng_ring_buffer_client_overwrite_rt_init();
2124 lttng_ring_buffer_client_discard_init();
2125 lttng_ring_buffer_client_discard_rt_init();
2126 lttng_counter_client_percpu_32_modular_init();
2127 lttng_counter_client_percpu_64_modular_init();
2128 lttng_perf_counter_init();
2130 * Invoke ust malloc wrapper init before starting other threads.
2132 lttng_ust_libc_wrapper_malloc_init();
2134 timeout_mode
= get_constructor_timeout(&constructor_timeout
);
2136 get_allow_blocking();
2138 ret
= sem_init(&constructor_wait
, 0, 0);
2143 ret
= setup_global_apps();
2145 assert(global_apps
.allowed
== 0);
2146 DBG("global apps setup returned %d", ret
);
2149 ret
= setup_local_apps();
2151 assert(local_apps
.allowed
== 0);
2152 DBG("local apps setup returned %d", ret
);
2155 /* A new thread created by pthread_create inherits the signal mask
2156 * from the parent. To avoid any signal being received by the
2157 * listener thread, we block all signals temporarily in the parent,
2158 * while we create the listener thread.
2160 sigfillset(&sig_all_blocked
);
2161 ret
= pthread_sigmask(SIG_SETMASK
, &sig_all_blocked
, &orig_parent_mask
);
2163 ERR("pthread_sigmask: %s", strerror(ret
));
2166 ret
= pthread_attr_init(&thread_attr
);
2168 ERR("pthread_attr_init: %s", strerror(ret
));
2170 ret
= pthread_attr_setdetachstate(&thread_attr
, PTHREAD_CREATE_DETACHED
);
2172 ERR("pthread_attr_setdetachstate: %s", strerror(ret
));
2175 if (global_apps
.allowed
) {
2176 pthread_mutex_lock(&ust_exit_mutex
);
2177 ret
= pthread_create(&global_apps
.ust_listener
, &thread_attr
,
2178 ust_listener_thread
, &global_apps
);
2180 ERR("pthread_create global: %s", strerror(ret
));
2182 global_apps
.thread_active
= 1;
2183 pthread_mutex_unlock(&ust_exit_mutex
);
2185 handle_register_done(&global_apps
);
2188 if (local_apps
.allowed
) {
2189 pthread_mutex_lock(&ust_exit_mutex
);
2190 ret
= pthread_create(&local_apps
.ust_listener
, &thread_attr
,
2191 ust_listener_thread
, &local_apps
);
2193 ERR("pthread_create local: %s", strerror(ret
));
2195 local_apps
.thread_active
= 1;
2196 pthread_mutex_unlock(&ust_exit_mutex
);
2198 handle_register_done(&local_apps
);
2200 ret
= pthread_attr_destroy(&thread_attr
);
2202 ERR("pthread_attr_destroy: %s", strerror(ret
));
2205 /* Restore original signal mask in parent */
2206 ret
= pthread_sigmask(SIG_SETMASK
, &orig_parent_mask
, NULL
);
2208 ERR("pthread_sigmask: %s", strerror(ret
));
2211 switch (timeout_mode
) {
2212 case 1: /* timeout wait */
2214 ret
= sem_timedwait(&constructor_wait
,
2215 &constructor_timeout
);
2216 } while (ret
< 0 && errno
== EINTR
);
2220 ERR("Timed out waiting for lttng-sessiond");
2223 PERROR("sem_timedwait");
2226 ERR("Unexpected error \"%s\" returned by sem_timedwait",
2231 case -1:/* wait forever */
2233 ret
= sem_wait(&constructor_wait
);
2234 } while (ret
< 0 && errno
== EINTR
);
2241 ERR("Unexpected error \"%s\" returned by sem_wait",
2246 case 0: /* no timeout */
2252 void lttng_ust_cleanup(int exiting
)
2254 cleanup_sock_info(&global_apps
, exiting
);
2255 cleanup_sock_info(&local_apps
, exiting
);
2256 local_apps
.allowed
= 0;
2257 global_apps
.allowed
= 0;
2259 * The teardown in this function all affect data structures
2260 * accessed under the UST lock by the listener thread. This
2261 * lock, along with the lttng_ust_comm_should_quit flag, ensure
2262 * that none of these threads are accessing this data at this
2265 lttng_ust_abi_exit();
2266 lttng_ust_abi_events_exit();
2267 lttng_perf_counter_exit();
2268 lttng_ring_buffer_client_discard_rt_exit();
2269 lttng_ring_buffer_client_discard_exit();
2270 lttng_ring_buffer_client_overwrite_rt_exit();
2271 lttng_ring_buffer_client_overwrite_exit();
2272 lttng_ring_buffer_metadata_client_exit();
2273 lttng_counter_client_percpu_32_modular_exit();
2274 lttng_counter_client_percpu_64_modular_exit();
2275 lttng_ust_statedump_destroy();
2276 lttng_ust_tp_exit();
2278 /* Reinitialize values for fork */
2279 sem_count
= sem_count_initial_value
;
2280 lttng_ust_comm_should_quit
= 0;
2285 void __attribute__((destructor
)) lttng_ust_exit(void)
2290 * Using pthread_cancel here because:
2291 * A) we don't want to hang application teardown.
2292 * B) the thread is not allocating any resource.
2296 * Require the communication thread to quit. Synchronize with
2297 * mutexes to ensure it is not in a mutex critical section when
2298 * pthread_cancel is later called.
2301 lttng_ust_comm_should_quit
= 1;
2304 pthread_mutex_lock(&ust_exit_mutex
);
2305 /* cancel threads */
2306 if (global_apps
.thread_active
) {
2307 ret
= pthread_cancel(global_apps
.ust_listener
);
2309 ERR("Error cancelling global ust listener thread: %s",
2312 global_apps
.thread_active
= 0;
2315 if (local_apps
.thread_active
) {
2316 ret
= pthread_cancel(local_apps
.ust_listener
);
2318 ERR("Error cancelling local ust listener thread: %s",
2321 local_apps
.thread_active
= 0;
2324 pthread_mutex_unlock(&ust_exit_mutex
);
2327 * Do NOT join threads: use of sys_futex makes it impossible to
2328 * join the threads without using async-cancel, but async-cancel
2329 * is delivered by a signal, which could hit the target thread
2330 * anywhere in its code path, including while the ust_lock() is
2331 * held, causing a deadlock for the other thread. Let the OS
2332 * cleanup the threads if there are stalled in a syscall.
2334 lttng_ust_cleanup(1);
2338 void ust_context_ns_reset(void)
2340 lttng_context_pid_ns_reset();
2341 lttng_context_cgroup_ns_reset();
2342 lttng_context_ipc_ns_reset();
2343 lttng_context_mnt_ns_reset();
2344 lttng_context_net_ns_reset();
2345 lttng_context_user_ns_reset();
2346 lttng_context_time_ns_reset();
2347 lttng_context_uts_ns_reset();
2351 void ust_context_vuids_reset(void)
2353 lttng_context_vuid_reset();
2354 lttng_context_veuid_reset();
2355 lttng_context_vsuid_reset();
2359 void ust_context_vgids_reset(void)
2361 lttng_context_vgid_reset();
2362 lttng_context_vegid_reset();
2363 lttng_context_vsgid_reset();
2367 * We exclude the worker threads across fork and clone (except
2368 * CLONE_VM), because these system calls only keep the forking thread
2369 * running in the child. Therefore, we don't want to call fork or clone
2370 * in the middle of an tracepoint or ust tracing state modification.
2371 * Holding this mutex protects these structures across fork and clone.
2373 void ust_before_fork(sigset_t
*save_sigset
)
2376 * Disable signals. This is to avoid that the child intervenes
2377 * before it is properly setup for tracing. It is safer to
2378 * disable all signals, because then we know we are not breaking
2379 * anything by restoring the original mask.
2384 /* Fixup lttng-ust TLS. */
2385 lttng_ust_fixup_tls();
2387 if (URCU_TLS(lttng_ust_nest_count
))
2389 /* Disable signals */
2390 sigfillset(&all_sigs
);
2391 ret
= sigprocmask(SIG_BLOCK
, &all_sigs
, save_sigset
);
2393 PERROR("sigprocmask");
2396 pthread_mutex_lock(&ust_fork_mutex
);
2399 lttng_ust_urcu_before_fork();
2400 lttng_ust_lock_fd_tracker();
2404 static void ust_after_fork_common(sigset_t
*restore_sigset
)
2408 DBG("process %d", getpid());
2409 lttng_perf_unlock();
2410 lttng_ust_unlock_fd_tracker();
2413 pthread_mutex_unlock(&ust_fork_mutex
);
2415 /* Restore signals */
2416 ret
= sigprocmask(SIG_SETMASK
, restore_sigset
, NULL
);
2418 PERROR("sigprocmask");
2422 void ust_after_fork_parent(sigset_t
*restore_sigset
)
2424 if (URCU_TLS(lttng_ust_nest_count
))
2426 DBG("process %d", getpid());
2427 lttng_ust_urcu_after_fork_parent();
2428 /* Release mutexes and reenable signals */
2429 ust_after_fork_common(restore_sigset
);
2433 * After fork, in the child, we need to cleanup all the leftover state,
2434 * except the worker thread which already magically disappeared thanks
2435 * to the weird Linux fork semantics. After tyding up, we call
2436 * lttng_ust_init() again to start over as a new PID.
2438 * This is meant for forks() that have tracing in the child between the
2439 * fork and following exec call (if there is any).
2441 void ust_after_fork_child(sigset_t
*restore_sigset
)
2443 if (URCU_TLS(lttng_ust_nest_count
))
2445 lttng_context_vpid_reset();
2446 lttng_context_vtid_reset();
2447 lttng_ust_context_procname_reset();
2448 ust_context_ns_reset();
2449 ust_context_vuids_reset();
2450 ust_context_vgids_reset();
2451 DBG("process %d", getpid());
2452 /* Release urcu mutexes */
2453 lttng_ust_urcu_after_fork_child();
2454 lttng_ust_cleanup(0);
2455 /* Release mutexes and reenable signals */
2456 ust_after_fork_common(restore_sigset
);
2460 void ust_after_setns(void)
2462 ust_context_ns_reset();
2463 ust_context_vuids_reset();
2464 ust_context_vgids_reset();
2467 void ust_after_unshare(void)
2469 ust_context_ns_reset();
2470 ust_context_vuids_reset();
2471 ust_context_vgids_reset();
2474 void ust_after_setuid(void)
2476 ust_context_vuids_reset();
2479 void ust_after_seteuid(void)
2481 ust_context_vuids_reset();
2484 void ust_after_setreuid(void)
2486 ust_context_vuids_reset();
2489 void ust_after_setresuid(void)
2491 ust_context_vuids_reset();
2494 void ust_after_setgid(void)
2496 ust_context_vgids_reset();
2499 void ust_after_setegid(void)
2501 ust_context_vgids_reset();
2504 void ust_after_setregid(void)
2506 ust_context_vgids_reset();
2509 void ust_after_setresgid(void)
2511 ust_context_vgids_reset();
2514 void lttng_ust_sockinfo_session_enabled(void *owner
)
2516 struct sock_info
*sock_info
= owner
;
2517 sock_info
->statedump_pending
= 1;