Commit | Line | Data |
---|---|---|
2691221a MD |
1 | /* |
2 | * lttng-ust-comm.c | |
3 | * | |
4 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> | |
5 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
6 | * | |
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. | |
11 | * | |
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. | |
16 | * | |
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 | |
20 | */ | |
21 | ||
22 | #include <sys/types.h> | |
23 | #include <sys/socket.h> | |
2629549e | 24 | #include <sys/prctl.h> |
2691221a MD |
25 | #include <unistd.h> |
26 | #include <errno.h> | |
d9e99d10 | 27 | #include <pthread.h> |
11ff9c7d MD |
28 | #include <semaphore.h> |
29 | #include <time.h> | |
1ea11eab | 30 | #include <assert.h> |
e822f505 | 31 | #include <signal.h> |
95259bd0 | 32 | #include <urcu/uatomic.h> |
1ea11eab | 33 | |
edaa1431 MD |
34 | #include <lttng-ust-comm.h> |
35 | #include <ust/usterr-signal-safe.h> | |
36 | #include <ust/lttng-ust-abi.h> | |
37 | #include <ust/tracepoint.h> | |
d0a1ae63 | 38 | #include <ust/tracepoint-internal.h> |
e822f505 | 39 | #include <ust/ust.h> |
edaa1431 MD |
40 | |
41 | /* | |
42 | * Has lttng ust comm constructor been called ? | |
43 | */ | |
44 | static int initialized; | |
45 | ||
1ea11eab MD |
46 | /* |
47 | * communication thread mutex. Held when handling a command, also held | |
48 | * by fork() to deal with removal of threads, and by exit path. | |
49 | */ | |
50 | static pthread_mutex_t lttng_ust_comm_mutex = PTHREAD_MUTEX_INITIALIZER; | |
51 | ||
52 | /* Should the ust comm thread quit ? */ | |
53 | static int lttng_ust_comm_should_quit; | |
54 | ||
11ff9c7d MD |
55 | /* |
56 | * Wait for either of these before continuing to the main | |
57 | * program: | |
58 | * - the register_done message from sessiond daemon | |
59 | * (will let the sessiond daemon enable sessions before main | |
60 | * starts.) | |
61 | * - sessiond daemon is not reachable. | |
62 | * - timeout (ensuring applications are resilient to session | |
63 | * daemon problems). | |
64 | */ | |
65 | static sem_t constructor_wait; | |
950aab0c MD |
66 | /* |
67 | * Doing this for both the global and local sessiond. | |
68 | */ | |
95259bd0 | 69 | static int sem_count = { 2 }; |
11ff9c7d | 70 | |
1ea11eab MD |
71 | /* |
72 | * Info about socket and associated listener thread. | |
73 | */ | |
74 | struct sock_info { | |
11ff9c7d | 75 | const char *name; |
1ea11eab MD |
76 | char sock_path[PATH_MAX]; |
77 | int socket; | |
78 | pthread_t ust_listener; /* listener thread */ | |
46050b1a | 79 | int root_handle; |
8d20bf54 MD |
80 | int constructor_sem_posted; |
81 | int allowed; | |
1ea11eab | 82 | }; |
2691221a MD |
83 | |
84 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 85 | struct sock_info global_apps = { |
11ff9c7d | 86 | .name = "global", |
1ea11eab MD |
87 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, |
88 | .socket = -1, | |
46050b1a | 89 | .root_handle = -1, |
8d20bf54 | 90 | .allowed = 1, |
1ea11eab | 91 | }; |
2691221a MD |
92 | |
93 | /* TODO: allow global_apps_sock_path override */ | |
94 | ||
1ea11eab | 95 | struct sock_info local_apps = { |
11ff9c7d | 96 | .name = "local", |
1ea11eab | 97 | .socket = -1, |
46050b1a | 98 | .root_handle = -1, |
8d20bf54 | 99 | .allowed = 0, /* Check setuid bit first */ |
1ea11eab | 100 | }; |
2691221a | 101 | |
edaa1431 MD |
102 | extern void ltt_ring_buffer_client_overwrite_init(void); |
103 | extern void ltt_ring_buffer_client_discard_init(void); | |
104 | extern void ltt_ring_buffer_metadata_client_init(void); | |
105 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
106 | extern void ltt_ring_buffer_client_discard_exit(void); | |
107 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
108 | ||
2691221a | 109 | static |
8d20bf54 | 110 | int setup_local_apps(void) |
2691221a MD |
111 | { |
112 | const char *home_dir; | |
2691221a | 113 | |
8d20bf54 MD |
114 | /* |
115 | * Disallow per-user tracing for setuid binaries. | |
116 | */ | |
117 | if (getuid() != geteuid()) { | |
118 | local_apps.allowed = 0; | |
d0a1ae63 | 119 | return 0; |
8d20bf54 MD |
120 | } else { |
121 | local_apps.allowed = 1; | |
122 | } | |
2691221a MD |
123 | home_dir = (const char *) getenv("HOME"); |
124 | if (!home_dir) | |
125 | return -ENOENT; | |
1ea11eab | 126 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 127 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
2691221a MD |
128 | return 0; |
129 | } | |
130 | ||
131 | static | |
132 | int register_app_to_sessiond(int socket) | |
133 | { | |
134 | ssize_t ret; | |
2629549e | 135 | int prctl_ret; |
2691221a | 136 | struct { |
e44418f3 MD |
137 | uint32_t major; |
138 | uint32_t minor; | |
2691221a | 139 | pid_t pid; |
5c33bde8 | 140 | pid_t ppid; |
2691221a | 141 | uid_t uid; |
83610856 | 142 | gid_t gid; |
2629549e | 143 | char name[16]; /* process name */ |
2691221a MD |
144 | } reg_msg; |
145 | ||
e44418f3 MD |
146 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
147 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 148 | reg_msg.pid = getpid(); |
5c33bde8 | 149 | reg_msg.ppid = getppid(); |
2691221a | 150 | reg_msg.uid = getuid(); |
83610856 | 151 | reg_msg.gid = getgid(); |
2629549e MD |
152 | prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0); |
153 | if (prctl_ret) { | |
154 | ERR("Error executing prctl"); | |
155 | return -errno; | |
156 | } | |
2691221a MD |
157 | |
158 | ret = lttcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); | |
159 | if (ret >= 0 && ret != sizeof(reg_msg)) | |
160 | return -EIO; | |
161 | return ret; | |
162 | } | |
163 | ||
d9e99d10 | 164 | static |
d3a492d1 | 165 | int send_reply(int sock, struct lttcomm_ust_reply *lur) |
d9e99d10 | 166 | { |
9eb62b9c | 167 | ssize_t len; |
d3a492d1 | 168 | |
a4be8962 | 169 | len = lttcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 170 | switch (len) { |
a4be8962 | 171 | case sizeof(*lur): |
d3a492d1 MD |
172 | DBG("message successfully sent"); |
173 | return 0; | |
174 | case -1: | |
175 | if (errno == ECONNRESET) { | |
176 | printf("remote end closed connection\n"); | |
177 | return 0; | |
178 | } | |
179 | return -1; | |
180 | default: | |
181 | printf("incorrect message size: %zd\n", len); | |
182 | return -1; | |
183 | } | |
184 | } | |
185 | ||
186 | static | |
edaa1431 | 187 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
188 | { |
189 | int ret; | |
190 | ||
edaa1431 MD |
191 | if (sock_info->constructor_sem_posted) |
192 | return 0; | |
193 | sock_info->constructor_sem_posted = 1; | |
95259bd0 MD |
194 | ret = uatomic_add_return(&sem_count, -1); |
195 | if (ret == 0) { | |
196 | ret = sem_post(&constructor_wait); | |
197 | assert(!ret); | |
198 | } | |
11ff9c7d MD |
199 | return 0; |
200 | } | |
201 | ||
202 | static | |
203 | int handle_message(struct sock_info *sock_info, | |
204 | int sock, struct lttcomm_ust_msg *lum) | |
d3a492d1 | 205 | { |
1ea11eab | 206 | int ret = 0; |
46050b1a MD |
207 | const struct objd_ops *ops; |
208 | struct lttcomm_ust_reply lur; | |
1ea11eab MD |
209 | |
210 | pthread_mutex_lock(<tng_ust_comm_mutex); | |
211 | ||
46050b1a MD |
212 | memset(&lur, 0, sizeof(lur)); |
213 | ||
1ea11eab | 214 | if (lttng_ust_comm_should_quit) { |
46050b1a | 215 | ret = -EPERM; |
1ea11eab MD |
216 | goto end; |
217 | } | |
9eb62b9c | 218 | |
46050b1a MD |
219 | ops = objd_ops(lum->handle); |
220 | if (!ops) { | |
221 | ret = -ENOENT; | |
222 | goto end; | |
1ea11eab | 223 | } |
46050b1a MD |
224 | |
225 | switch (lum->cmd) { | |
11ff9c7d MD |
226 | case LTTNG_UST_REGISTER_DONE: |
227 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 228 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
229 | else |
230 | ret = -EINVAL; | |
231 | break; | |
46050b1a MD |
232 | case LTTNG_UST_RELEASE: |
233 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
234 | ret = -EPERM; | |
235 | else | |
236 | ret = objd_unref(lum->handle); | |
d9e99d10 MD |
237 | break; |
238 | default: | |
46050b1a MD |
239 | if (ops->cmd) |
240 | ret = ops->cmd(lum->handle, lum->cmd, | |
241 | (unsigned long) &lum->u); | |
242 | else | |
243 | ret = -ENOSYS; | |
244 | break; | |
d9e99d10 | 245 | } |
46050b1a | 246 | |
1ea11eab | 247 | end: |
46050b1a MD |
248 | lur.handle = lum->handle; |
249 | lur.cmd = lum->cmd; | |
250 | lur.ret_val = ret; | |
251 | if (ret >= 0) { | |
252 | lur.ret_code = LTTCOMM_OK; | |
253 | } else { | |
254 | lur.ret_code = LTTCOMM_SESSION_FAIL; | |
255 | } | |
256 | ret = send_reply(sock, &lur); | |
257 | ||
1ea11eab MD |
258 | pthread_mutex_unlock(<tng_ust_comm_mutex); |
259 | return ret; | |
d9e99d10 MD |
260 | } |
261 | ||
46050b1a MD |
262 | static |
263 | void cleanup_sock_info(struct sock_info *sock_info) | |
264 | { | |
265 | int ret; | |
266 | ||
267 | if (sock_info->socket != -1) { | |
268 | ret = close(sock_info->socket); | |
269 | if (ret) { | |
270 | ERR("Error closing local apps socket"); | |
271 | } | |
272 | sock_info->socket = -1; | |
273 | } | |
274 | if (sock_info->root_handle != -1) { | |
275 | ret = objd_unref(sock_info->root_handle); | |
276 | if (ret) { | |
277 | ERR("Error unref root handle"); | |
278 | } | |
279 | sock_info->root_handle = -1; | |
280 | } | |
281 | } | |
282 | ||
1ea11eab MD |
283 | /* |
284 | * This thread does not allocate any resource, except within | |
285 | * handle_message, within mutex protection. This mutex protects against | |
286 | * fork and exit. | |
287 | * The other moment it allocates resources is at socket connexion, which | |
288 | * is also protected by the mutex. | |
289 | */ | |
d9e99d10 MD |
290 | static |
291 | void *ust_listener_thread(void *arg) | |
292 | { | |
1ea11eab MD |
293 | struct sock_info *sock_info = arg; |
294 | int sock, ret; | |
d9e99d10 | 295 | |
9eb62b9c MD |
296 | /* Restart trying to connect to the session daemon */ |
297 | restart: | |
1ea11eab MD |
298 | pthread_mutex_lock(<tng_ust_comm_mutex); |
299 | ||
300 | if (lttng_ust_comm_should_quit) { | |
301 | pthread_mutex_unlock(<tng_ust_comm_mutex); | |
302 | goto quit; | |
303 | } | |
9eb62b9c | 304 | |
1ea11eab MD |
305 | if (sock_info->socket != -1) { |
306 | ret = close(sock_info->socket); | |
307 | if (ret) { | |
11ff9c7d | 308 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
309 | } |
310 | sock_info->socket = -1; | |
311 | } | |
46050b1a | 312 | |
9eb62b9c MD |
313 | /* Check for sessiond availability with pipe TODO */ |
314 | ||
315 | /* Register */ | |
1ea11eab | 316 | ret = lttcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 317 | if (ret < 0) { |
11ff9c7d MD |
318 | ERR("Error connecting to %s apps socket", sock_info->name); |
319 | /* | |
320 | * If we cannot find the sessiond daemon, don't delay | |
321 | * constructor execution. | |
322 | */ | |
edaa1431 | 323 | ret = handle_register_done(sock_info); |
11ff9c7d | 324 | assert(!ret); |
1ea11eab | 325 | pthread_mutex_unlock(<tng_ust_comm_mutex); |
4eef2998 | 326 | sleep(5); |
1ea11eab | 327 | goto restart; |
46050b1a MD |
328 | } |
329 | ||
330 | sock_info->socket = sock = ret; | |
331 | ||
332 | /* | |
333 | * Create only one root handle per listener thread for the whole | |
334 | * process lifetime. | |
335 | */ | |
336 | if (sock_info->root_handle == -1) { | |
337 | ret = lttng_abi_create_root_handle(); | |
338 | if (ret) { | |
339 | ERR("Error creating root handle"); | |
340 | pthread_mutex_unlock(<tng_ust_comm_mutex); | |
341 | goto quit; | |
342 | } | |
343 | sock_info->root_handle = ret; | |
9eb62b9c | 344 | } |
1ea11eab | 345 | |
9eb62b9c MD |
346 | ret = register_app_to_sessiond(sock); |
347 | if (ret < 0) { | |
11ff9c7d MD |
348 | ERR("Error registering to %s apps socket", sock_info->name); |
349 | /* | |
350 | * If we cannot register to the sessiond daemon, don't | |
351 | * delay constructor execution. | |
352 | */ | |
edaa1431 | 353 | ret = handle_register_done(sock_info); |
11ff9c7d | 354 | assert(!ret); |
46050b1a | 355 | pthread_mutex_unlock(<tng_ust_comm_mutex); |
9eb62b9c MD |
356 | sleep(5); |
357 | goto restart; | |
358 | } | |
46050b1a MD |
359 | pthread_mutex_unlock(<tng_ust_comm_mutex); |
360 | ||
d9e99d10 MD |
361 | for (;;) { |
362 | ssize_t len; | |
e7723462 | 363 | struct lttcomm_ust_msg lum; |
d9e99d10 | 364 | |
e7723462 | 365 | len = lttcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
366 | switch (len) { |
367 | case 0: /* orderly shutdown */ | |
11ff9c7d | 368 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
d9e99d10 | 369 | goto end; |
e7723462 | 370 | case sizeof(lum): |
d9e99d10 | 371 | DBG("message received\n"); |
11ff9c7d | 372 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 373 | if (ret < 0) { |
11ff9c7d | 374 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
375 | } |
376 | continue; | |
377 | case -1: | |
378 | if (errno == ECONNRESET) { | |
11ff9c7d | 379 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
380 | goto end; |
381 | } | |
382 | goto end; | |
383 | default: | |
11ff9c7d | 384 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
385 | continue; |
386 | } | |
387 | ||
388 | } | |
389 | end: | |
9eb62b9c | 390 | goto restart; /* try to reconnect */ |
1ea11eab | 391 | quit: |
d9e99d10 MD |
392 | return NULL; |
393 | } | |
394 | ||
cf12a773 MD |
395 | /* |
396 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
397 | */ | |
11ff9c7d MD |
398 | static |
399 | int get_timeout(struct timespec *constructor_timeout) | |
400 | { | |
cf12a773 MD |
401 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
402 | char *str_delay; | |
11ff9c7d MD |
403 | int ret; |
404 | ||
cf12a773 MD |
405 | str_delay = getenv("UST_REGISTER_TIMEOUT"); |
406 | if (str_delay) { | |
407 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
408 | } | |
409 | ||
410 | switch (constructor_delay_ms) { | |
411 | case -1:/* fall-through */ | |
412 | case 0: | |
413 | return constructor_delay_ms; | |
414 | default: | |
415 | break; | |
416 | } | |
417 | ||
418 | /* | |
419 | * If we are unable to find the current time, don't wait. | |
420 | */ | |
421 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
422 | if (ret) { | |
423 | return -1; | |
424 | } | |
95259bd0 MD |
425 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
426 | constructor_timeout->tv_nsec += | |
427 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
428 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
429 | constructor_timeout->tv_sec++; | |
430 | constructor_timeout->tv_nsec -= 1000000000UL; | |
431 | } | |
cf12a773 | 432 | return 1; |
11ff9c7d | 433 | } |
d9e99d10 | 434 | |
2691221a MD |
435 | /* |
436 | * sessiond monitoring thread: monitor presence of global and per-user | |
437 | * sessiond by polling the application common named pipe. | |
438 | */ | |
439 | /* TODO */ | |
440 | ||
edaa1431 | 441 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 442 | { |
11ff9c7d | 443 | struct timespec constructor_timeout; |
cf12a773 | 444 | int timeout_mode; |
2691221a MD |
445 | int ret; |
446 | ||
edaa1431 MD |
447 | if (uatomic_xchg(&initialized, 1) == 1) |
448 | return; | |
449 | ||
450 | /* | |
451 | * We want precise control over the order in which we construct | |
452 | * our sub-libraries vs starting to receive commands from | |
453 | * sessiond (otherwise leading to errors when trying to create | |
454 | * sessiond before the init functions are completed). | |
455 | */ | |
2691221a | 456 | init_usterr(); |
edaa1431 MD |
457 | init_tracepoint(); |
458 | ltt_ring_buffer_metadata_client_init(); | |
459 | ltt_ring_buffer_client_overwrite_init(); | |
460 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 461 | |
cf12a773 | 462 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 463 | |
95259bd0 | 464 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
465 | assert(!ret); |
466 | ||
8d20bf54 | 467 | ret = setup_local_apps(); |
2691221a | 468 | if (ret) { |
8d20bf54 | 469 | ERR("Error setting up to local apps"); |
2691221a | 470 | } |
1ea11eab MD |
471 | ret = pthread_create(&local_apps.ust_listener, NULL, |
472 | ust_listener_thread, &local_apps); | |
11ff9c7d | 473 | |
8d20bf54 MD |
474 | if (local_apps.allowed) { |
475 | ret = pthread_create(&global_apps.ust_listener, NULL, | |
476 | ust_listener_thread, &global_apps); | |
477 | } else { | |
478 | handle_register_done(&local_apps); | |
479 | } | |
480 | ||
cf12a773 MD |
481 | switch (timeout_mode) { |
482 | case 1: /* timeout wait */ | |
95259bd0 MD |
483 | do { |
484 | ret = sem_timedwait(&constructor_wait, | |
485 | &constructor_timeout); | |
486 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
487 | if (ret < 0 && errno == ETIMEDOUT) { |
488 | ERR("Timed out waiting for ltt-sessiond"); | |
489 | } else { | |
490 | assert(!ret); | |
491 | } | |
492 | break; | |
7b766b16 | 493 | case -1:/* wait forever */ |
95259bd0 MD |
494 | do { |
495 | ret = sem_wait(&constructor_wait); | |
496 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 497 | assert(!ret); |
cf12a773 | 498 | break; |
7b766b16 | 499 | case 0: /* no timeout */ |
cf12a773 | 500 | break; |
11ff9c7d | 501 | } |
2691221a MD |
502 | } |
503 | ||
edaa1431 | 504 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
505 | { |
506 | int ret; | |
507 | ||
9eb62b9c MD |
508 | /* |
509 | * Using pthread_cancel here because: | |
510 | * A) we don't want to hang application teardown. | |
511 | * B) the thread is not allocating any resource. | |
512 | */ | |
1ea11eab MD |
513 | |
514 | /* | |
515 | * Require the communication thread to quit. Synchronize with | |
516 | * mutexes to ensure it is not in a mutex critical section when | |
517 | * pthread_cancel is later called. | |
518 | */ | |
519 | pthread_mutex_lock(<tng_ust_comm_mutex); | |
520 | lttng_ust_comm_should_quit = 1; | |
521 | pthread_mutex_unlock(<tng_ust_comm_mutex); | |
522 | ||
1ea11eab | 523 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c MD |
524 | if (ret) { |
525 | ERR("Error cancelling global ust listener thread"); | |
2691221a | 526 | } |
46050b1a MD |
527 | |
528 | cleanup_sock_info(&global_apps); | |
1ea11eab | 529 | |
8d20bf54 MD |
530 | if (local_apps.allowed) { |
531 | ret = pthread_cancel(local_apps.ust_listener); | |
532 | if (ret) { | |
533 | ERR("Error cancelling local ust listener thread"); | |
534 | } | |
1ea11eab | 535 | |
8d20bf54 MD |
536 | cleanup_sock_info(&local_apps); |
537 | } | |
1ea11eab | 538 | |
b35d179d | 539 | lttng_ust_abi_exit(); |
1ea11eab | 540 | ltt_events_exit(); |
edaa1431 MD |
541 | ltt_ring_buffer_client_discard_exit(); |
542 | ltt_ring_buffer_client_overwrite_exit(); | |
543 | ltt_ring_buffer_metadata_client_exit(); | |
544 | exit_tracepoint(); | |
2691221a | 545 | } |
e822f505 MD |
546 | |
547 | /* | |
548 | * We exclude the worker threads across fork and clone (except | |
549 | * CLONE_VM), because these system calls only keep the forking thread | |
550 | * running in the child. Therefore, we don't want to call fork or clone | |
551 | * in the middle of an tracepoint or ust tracing state modification. | |
552 | * Holding this mutex protects these structures across fork and clone. | |
553 | */ | |
554 | void ust_before_fork(ust_fork_info_t *fork_info) | |
555 | { | |
556 | /* | |
557 | * Disable signals. This is to avoid that the child intervenes | |
558 | * before it is properly setup for tracing. It is safer to | |
559 | * disable all signals, because then we know we are not breaking | |
560 | * anything by restoring the original mask. | |
561 | */ | |
562 | sigset_t all_sigs; | |
563 | int ret; | |
564 | ||
565 | /* Disable signals */ | |
566 | sigfillset(&all_sigs); | |
567 | ret = sigprocmask(SIG_BLOCK, &all_sigs, &fork_info->orig_sigs); | |
568 | if (ret == -1) { | |
569 | PERROR("sigprocmask"); | |
570 | } | |
571 | pthread_mutex_lock(<tng_ust_comm_mutex); | |
572 | rcu_bp_before_fork(); | |
573 | } | |
574 | ||
575 | static void ust_after_fork_common(ust_fork_info_t *fork_info) | |
576 | { | |
577 | int ret; | |
578 | ||
579 | pthread_mutex_unlock(<tng_ust_comm_mutex); | |
580 | /* Restore signals */ | |
581 | ret = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL); | |
582 | if (ret == -1) { | |
583 | PERROR("sigprocmask"); | |
584 | } | |
585 | } | |
586 | ||
587 | void ust_after_fork_parent(ust_fork_info_t *fork_info) | |
588 | { | |
589 | rcu_bp_after_fork_parent(); | |
590 | /* Release mutexes and reenable signals */ | |
591 | ust_after_fork_common(fork_info); | |
592 | } | |
593 | ||
594 | void ust_after_fork_child(ust_fork_info_t *fork_info) | |
595 | { | |
596 | /* Release urcu mutexes */ | |
597 | rcu_bp_after_fork_child(); | |
598 | /* Release mutexes and reenable signals */ | |
599 | ust_after_fork_common(fork_info); | |
600 | } |