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 | ||
80e2814b | 22 | #define _LGPL_SOURCE |
2691221a MD |
23 | #include <sys/types.h> |
24 | #include <sys/socket.h> | |
7fc90dca MD |
25 | #include <sys/mman.h> |
26 | #include <sys/stat.h> | |
58d4b2a2 MD |
27 | #include <sys/types.h> |
28 | #include <sys/wait.h> | |
7fc90dca | 29 | #include <fcntl.h> |
2691221a MD |
30 | #include <unistd.h> |
31 | #include <errno.h> | |
d9e99d10 | 32 | #include <pthread.h> |
11ff9c7d MD |
33 | #include <semaphore.h> |
34 | #include <time.h> | |
1ea11eab | 35 | #include <assert.h> |
e822f505 | 36 | #include <signal.h> |
95259bd0 | 37 | #include <urcu/uatomic.h> |
80e2814b | 38 | #include <urcu/futex.h> |
c117fb1b | 39 | #include <urcu/compiler.h> |
1ea11eab | 40 | |
4318ae1b | 41 | #include <lttng/ust-events.h> |
4318ae1b | 42 | #include <lttng/ust-abi.h> |
4318ae1b | 43 | #include <lttng/ust.h> |
44c72f10 MD |
44 | #include <ust-comm.h> |
45 | #include <usterr-signal-safe.h> | |
46 | #include "tracepoint-internal.h" | |
b751f722 | 47 | #include "ltt-tracer-core.h" |
08114193 | 48 | #include "compat.h" |
f645cfa7 | 49 | #include "../libringbuffer/tlsfixup.h" |
edaa1431 MD |
50 | |
51 | /* | |
52 | * Has lttng ust comm constructor been called ? | |
53 | */ | |
54 | static int initialized; | |
55 | ||
1ea11eab | 56 | /* |
17dfb34b MD |
57 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
58 | * Held when handling a command, also held by fork() to deal with | |
59 | * removal of threads, and by exit path. | |
1ea11eab | 60 | */ |
1ea11eab MD |
61 | |
62 | /* Should the ust comm thread quit ? */ | |
63 | static int lttng_ust_comm_should_quit; | |
64 | ||
11ff9c7d MD |
65 | /* |
66 | * Wait for either of these before continuing to the main | |
67 | * program: | |
68 | * - the register_done message from sessiond daemon | |
69 | * (will let the sessiond daemon enable sessions before main | |
70 | * starts.) | |
71 | * - sessiond daemon is not reachable. | |
72 | * - timeout (ensuring applications are resilient to session | |
73 | * daemon problems). | |
74 | */ | |
75 | static sem_t constructor_wait; | |
950aab0c MD |
76 | /* |
77 | * Doing this for both the global and local sessiond. | |
78 | */ | |
95259bd0 | 79 | static int sem_count = { 2 }; |
11ff9c7d | 80 | |
e8508a49 MD |
81 | /* |
82 | * Counting nesting within lttng-ust. Used to ensure that calling fork() | |
83 | * from liblttng-ust does not execute the pre/post fork handlers. | |
84 | */ | |
85 | static int __thread lttng_ust_nest_count; | |
86 | ||
1ea11eab MD |
87 | /* |
88 | * Info about socket and associated listener thread. | |
89 | */ | |
90 | struct sock_info { | |
11ff9c7d | 91 | const char *name; |
1ea11eab | 92 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 93 | int root_handle; |
8d20bf54 MD |
94 | int constructor_sem_posted; |
95 | int allowed; | |
44e073f5 | 96 | int global; |
7fc90dca MD |
97 | |
98 | char sock_path[PATH_MAX]; | |
99 | int socket; | |
100 | ||
101 | char wait_shm_path[PATH_MAX]; | |
102 | char *wait_shm_mmap; | |
1ea11eab | 103 | }; |
2691221a MD |
104 | |
105 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 106 | struct sock_info global_apps = { |
11ff9c7d | 107 | .name = "global", |
44e073f5 | 108 | .global = 1, |
7fc90dca | 109 | |
46050b1a | 110 | .root_handle = -1, |
8d20bf54 | 111 | .allowed = 1, |
7fc90dca MD |
112 | |
113 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
114 | .socket = -1, | |
115 | ||
116 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 117 | }; |
2691221a MD |
118 | |
119 | /* TODO: allow global_apps_sock_path override */ | |
120 | ||
1ea11eab | 121 | struct sock_info local_apps = { |
11ff9c7d | 122 | .name = "local", |
44e073f5 | 123 | .global = 0, |
46050b1a | 124 | .root_handle = -1, |
8d20bf54 | 125 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
126 | |
127 | .socket = -1, | |
1ea11eab | 128 | }; |
2691221a | 129 | |
37ed587a MD |
130 | static int wait_poll_fallback; |
131 | ||
edaa1431 MD |
132 | extern void ltt_ring_buffer_client_overwrite_init(void); |
133 | extern void ltt_ring_buffer_client_discard_init(void); | |
134 | extern void ltt_ring_buffer_metadata_client_init(void); | |
135 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
136 | extern void ltt_ring_buffer_client_discard_exit(void); | |
137 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
138 | ||
2691221a | 139 | static |
8d20bf54 | 140 | int setup_local_apps(void) |
2691221a MD |
141 | { |
142 | const char *home_dir; | |
7fc90dca | 143 | uid_t uid; |
2691221a | 144 | |
7fc90dca | 145 | uid = getuid(); |
8d20bf54 MD |
146 | /* |
147 | * Disallow per-user tracing for setuid binaries. | |
148 | */ | |
7fc90dca | 149 | if (uid != geteuid()) { |
8d20bf54 | 150 | local_apps.allowed = 0; |
d0a1ae63 | 151 | return 0; |
8d20bf54 MD |
152 | } else { |
153 | local_apps.allowed = 1; | |
154 | } | |
2691221a MD |
155 | home_dir = (const char *) getenv("HOME"); |
156 | if (!home_dir) | |
157 | return -ENOENT; | |
1ea11eab | 158 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 159 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
160 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
161 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
162 | return 0; |
163 | } | |
164 | ||
165 | static | |
166 | int register_app_to_sessiond(int socket) | |
167 | { | |
168 | ssize_t ret; | |
169 | struct { | |
e44418f3 MD |
170 | uint32_t major; |
171 | uint32_t minor; | |
2691221a | 172 | pid_t pid; |
5c33bde8 | 173 | pid_t ppid; |
2691221a | 174 | uid_t uid; |
83610856 | 175 | gid_t gid; |
c117fb1b | 176 | uint32_t bits_per_long; |
2629549e | 177 | char name[16]; /* process name */ |
2691221a MD |
178 | } reg_msg; |
179 | ||
e44418f3 MD |
180 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
181 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 182 | reg_msg.pid = getpid(); |
5c33bde8 | 183 | reg_msg.ppid = getppid(); |
2691221a | 184 | reg_msg.uid = getuid(); |
83610856 | 185 | reg_msg.gid = getgid(); |
c117fb1b | 186 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
08114193 | 187 | lttng_ust_getprocname(reg_msg.name); |
2691221a | 188 | |
57773204 | 189 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
190 | if (ret >= 0 && ret != sizeof(reg_msg)) |
191 | return -EIO; | |
192 | return ret; | |
193 | } | |
194 | ||
d9e99d10 | 195 | static |
57773204 | 196 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 197 | { |
9eb62b9c | 198 | ssize_t len; |
d3a492d1 | 199 | |
57773204 | 200 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 201 | switch (len) { |
a4be8962 | 202 | case sizeof(*lur): |
d3a492d1 MD |
203 | DBG("message successfully sent"); |
204 | return 0; | |
205 | case -1: | |
206 | if (errno == ECONNRESET) { | |
207 | printf("remote end closed connection\n"); | |
208 | return 0; | |
209 | } | |
210 | return -1; | |
211 | default: | |
212 | printf("incorrect message size: %zd\n", len); | |
213 | return -1; | |
214 | } | |
215 | } | |
216 | ||
217 | static | |
edaa1431 | 218 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
219 | { |
220 | int ret; | |
221 | ||
edaa1431 MD |
222 | if (sock_info->constructor_sem_posted) |
223 | return 0; | |
224 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
225 | if (uatomic_read(&sem_count) <= 0) { |
226 | return 0; | |
227 | } | |
95259bd0 MD |
228 | ret = uatomic_add_return(&sem_count, -1); |
229 | if (ret == 0) { | |
230 | ret = sem_post(&constructor_wait); | |
231 | assert(!ret); | |
232 | } | |
11ff9c7d MD |
233 | return 0; |
234 | } | |
235 | ||
236 | static | |
237 | int handle_message(struct sock_info *sock_info, | |
57773204 | 238 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 239 | { |
1ea11eab | 240 | int ret = 0; |
b61ce3b2 | 241 | const struct lttng_ust_objd_ops *ops; |
57773204 | 242 | struct ustcomm_ust_reply lur; |
193183fb | 243 | int shm_fd, wait_fd; |
ef9ff354 | 244 | union ust_args args; |
40003310 | 245 | ssize_t len; |
1ea11eab | 246 | |
17dfb34b | 247 | ust_lock(); |
1ea11eab | 248 | |
46050b1a MD |
249 | memset(&lur, 0, sizeof(lur)); |
250 | ||
1ea11eab | 251 | if (lttng_ust_comm_should_quit) { |
46050b1a | 252 | ret = -EPERM; |
1ea11eab MD |
253 | goto end; |
254 | } | |
9eb62b9c | 255 | |
46050b1a MD |
256 | ops = objd_ops(lum->handle); |
257 | if (!ops) { | |
258 | ret = -ENOENT; | |
259 | goto end; | |
1ea11eab | 260 | } |
46050b1a MD |
261 | |
262 | switch (lum->cmd) { | |
11ff9c7d MD |
263 | case LTTNG_UST_REGISTER_DONE: |
264 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 265 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
266 | else |
267 | ret = -EINVAL; | |
268 | break; | |
46050b1a MD |
269 | case LTTNG_UST_RELEASE: |
270 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
271 | ret = -EPERM; | |
272 | else | |
d4419b81 | 273 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 MD |
274 | break; |
275 | default: | |
46050b1a MD |
276 | if (ops->cmd) |
277 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
278 | (unsigned long) &lum->u, |
279 | &args); | |
46050b1a MD |
280 | else |
281 | ret = -ENOSYS; | |
282 | break; | |
d9e99d10 | 283 | } |
46050b1a | 284 | |
1ea11eab | 285 | end: |
46050b1a MD |
286 | lur.handle = lum->handle; |
287 | lur.cmd = lum->cmd; | |
288 | lur.ret_val = ret; | |
289 | if (ret >= 0) { | |
57773204 | 290 | lur.ret_code = USTCOMM_OK; |
46050b1a | 291 | } else { |
57773204 | 292 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 293 | lur.ret_code = ret; |
46050b1a | 294 | } |
e6ea14c5 MD |
295 | if (ret >= 0) { |
296 | switch (lum->cmd) { | |
297 | case LTTNG_UST_STREAM: | |
298 | /* | |
299 | * Special-case reply to send stream info. | |
300 | * Use lum.u output. | |
301 | */ | |
302 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; | |
303 | shm_fd = *args.stream.shm_fd; | |
304 | wait_fd = *args.stream.wait_fd; | |
305 | break; | |
306 | case LTTNG_UST_METADATA: | |
307 | case LTTNG_UST_CHANNEL: | |
308 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; | |
309 | shm_fd = *args.channel.shm_fd; | |
310 | wait_fd = *args.channel.wait_fd; | |
311 | break; | |
312 | case LTTNG_UST_TRACER_VERSION: | |
313 | lur.u.version = lum->u.version; | |
314 | break; | |
315 | case LTTNG_UST_TRACEPOINT_LIST_GET: | |
316 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); | |
317 | break; | |
318 | } | |
381c0f1e | 319 | } |
46050b1a | 320 | ret = send_reply(sock, &lur); |
193183fb MD |
321 | if (ret < 0) { |
322 | perror("error sending reply"); | |
323 | goto error; | |
324 | } | |
46050b1a | 325 | |
824f40b8 MD |
326 | if ((lum->cmd == LTTNG_UST_STREAM |
327 | || lum->cmd == LTTNG_UST_CHANNEL | |
328 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 329 | && lur.ret_code == USTCOMM_OK) { |
50be2fc4 MD |
330 | int sendret = 0; |
331 | ||
381c0f1e | 332 | /* we also need to send the file descriptors. */ |
57773204 | 333 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 334 | &shm_fd, &shm_fd, |
381c0f1e MD |
335 | 1, sizeof(int)); |
336 | if (ret < 0) { | |
337 | perror("send shm_fd"); | |
50be2fc4 | 338 | sendret = ret; |
381c0f1e | 339 | } |
50be2fc4 MD |
340 | /* |
341 | * The sessiond expects 2 file descriptors, even upon | |
342 | * error. | |
343 | */ | |
57773204 | 344 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 345 | &wait_fd, &wait_fd, |
381c0f1e MD |
346 | 1, sizeof(int)); |
347 | if (ret < 0) { | |
348 | perror("send wait_fd"); | |
349 | goto error; | |
350 | } | |
50be2fc4 MD |
351 | if (sendret) { |
352 | ret = sendret; | |
353 | goto error; | |
354 | } | |
381c0f1e | 355 | } |
40003310 MD |
356 | /* |
357 | * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field | |
358 | * after the reply. | |
359 | */ | |
360 | if (lur.ret_code == USTCOMM_OK) { | |
361 | switch (lum->cmd) { | |
362 | case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET: | |
363 | len = ustcomm_send_unix_sock(sock, | |
364 | &args.field_list.entry, | |
365 | sizeof(args.field_list.entry)); | |
366 | if (len != sizeof(args.field_list.entry)) { | |
367 | ret = -1; | |
368 | goto error; | |
369 | } | |
370 | } | |
371 | } | |
ef9ff354 MD |
372 | /* |
373 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
374 | * sent to the sessiond. We can therefore close those fds. Note |
375 | * that we keep the write side of the wait_fd open, but close | |
376 | * the read side. | |
ef9ff354 MD |
377 | */ |
378 | if (lur.ret_code == USTCOMM_OK) { | |
379 | switch (lum->cmd) { | |
380 | case LTTNG_UST_STREAM: | |
381 | if (shm_fd >= 0) { | |
382 | ret = close(shm_fd); | |
383 | if (ret) { | |
384 | PERROR("Error closing stream shm_fd"); | |
385 | } | |
386 | *args.stream.shm_fd = -1; | |
387 | } | |
388 | if (wait_fd >= 0) { | |
389 | ret = close(wait_fd); | |
390 | if (ret) { | |
391 | PERROR("Error closing stream wait_fd"); | |
392 | } | |
393 | *args.stream.wait_fd = -1; | |
394 | } | |
395 | break; | |
396 | case LTTNG_UST_METADATA: | |
397 | case LTTNG_UST_CHANNEL: | |
398 | if (shm_fd >= 0) { | |
399 | ret = close(shm_fd); | |
400 | if (ret) { | |
401 | PERROR("Error closing channel shm_fd"); | |
402 | } | |
403 | *args.channel.shm_fd = -1; | |
404 | } | |
405 | if (wait_fd >= 0) { | |
406 | ret = close(wait_fd); | |
407 | if (ret) { | |
408 | PERROR("Error closing channel wait_fd"); | |
409 | } | |
410 | *args.channel.wait_fd = -1; | |
411 | } | |
412 | break; | |
413 | } | |
414 | } | |
415 | ||
381c0f1e | 416 | error: |
17dfb34b | 417 | ust_unlock(); |
1ea11eab | 418 | return ret; |
d9e99d10 MD |
419 | } |
420 | ||
46050b1a | 421 | static |
efe0de09 | 422 | void cleanup_sock_info(struct sock_info *sock_info, int exiting) |
46050b1a MD |
423 | { |
424 | int ret; | |
425 | ||
426 | if (sock_info->socket != -1) { | |
e6973a89 | 427 | ret = ustcomm_close_unix_sock(sock_info->socket); |
46050b1a | 428 | if (ret) { |
7fc90dca | 429 | ERR("Error closing apps socket"); |
46050b1a MD |
430 | } |
431 | sock_info->socket = -1; | |
432 | } | |
433 | if (sock_info->root_handle != -1) { | |
d4419b81 | 434 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
435 | if (ret) { |
436 | ERR("Error unref root handle"); | |
437 | } | |
438 | sock_info->root_handle = -1; | |
439 | } | |
318dfea9 | 440 | sock_info->constructor_sem_posted = 0; |
efe0de09 MD |
441 | /* |
442 | * wait_shm_mmap is used by listener threads outside of the | |
443 | * ust lock, so we cannot tear it down ourselves, because we | |
444 | * cannot join on these threads. Leave this task to the OS | |
445 | * process exit. | |
446 | */ | |
447 | if (!exiting && sock_info->wait_shm_mmap) { | |
7fc90dca MD |
448 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); |
449 | if (ret) { | |
450 | ERR("Error unmapping wait shm"); | |
451 | } | |
452 | sock_info->wait_shm_mmap = NULL; | |
453 | } | |
454 | } | |
455 | ||
58d4b2a2 | 456 | /* |
33bbeb90 MD |
457 | * Using fork to set umask in the child process (not multi-thread safe). |
458 | * We deal with the shm_open vs ftruncate race (happening when the | |
459 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
460 | * safety against shm_unlink) by simply letting the mmap fail and | |
461 | * retrying after a few seconds. | |
462 | * For global shm, everybody has rw access to it until the sessiond | |
463 | * starts. | |
58d4b2a2 | 464 | */ |
7fc90dca | 465 | static |
58d4b2a2 | 466 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 467 | { |
7fc90dca | 468 | int wait_shm_fd, ret; |
58d4b2a2 | 469 | pid_t pid; |
44e073f5 | 470 | |
58d4b2a2 | 471 | /* |
33bbeb90 | 472 | * Try to open read-only. |
58d4b2a2 | 473 | */ |
33bbeb90 | 474 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
475 | if (wait_shm_fd >= 0) { |
476 | goto end; | |
477 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
478 | /* | |
33bbeb90 MD |
479 | * Real-only open did not work, and it's not because the |
480 | * entry was not present. It's a failure that prohibits | |
481 | * using shm. | |
58d4b2a2 | 482 | */ |
7fc90dca | 483 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 484 | goto end; |
7fc90dca MD |
485 | } |
486 | /* | |
58d4b2a2 MD |
487 | * If the open failed because the file did not exist, try |
488 | * creating it ourself. | |
7fc90dca | 489 | */ |
e8508a49 | 490 | lttng_ust_nest_count++; |
58d4b2a2 | 491 | pid = fork(); |
e8508a49 | 492 | lttng_ust_nest_count--; |
58d4b2a2 MD |
493 | if (pid > 0) { |
494 | int status; | |
495 | ||
496 | /* | |
497 | * Parent: wait for child to return, in which case the | |
498 | * shared memory map will have been created. | |
499 | */ | |
500 | pid = wait(&status); | |
b7d3cb32 | 501 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
502 | wait_shm_fd = -1; |
503 | goto end; | |
7fc90dca | 504 | } |
58d4b2a2 MD |
505 | /* |
506 | * Try to open read-only again after creation. | |
507 | */ | |
33bbeb90 | 508 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
509 | if (wait_shm_fd < 0) { |
510 | /* | |
511 | * Real-only open did not work. It's a failure | |
512 | * that prohibits using shm. | |
513 | */ | |
514 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
515 | goto end; | |
516 | } | |
517 | goto end; | |
518 | } else if (pid == 0) { | |
519 | int create_mode; | |
520 | ||
521 | /* Child */ | |
33bbeb90 | 522 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 523 | if (sock_info->global) |
33bbeb90 | 524 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
525 | /* |
526 | * We're alone in a child process, so we can modify the | |
527 | * process-wide umask. | |
528 | */ | |
33bbeb90 | 529 | umask(~create_mode); |
58d4b2a2 | 530 | /* |
33bbeb90 MD |
531 | * Try creating shm (or get rw access). |
532 | * We don't do an exclusive open, because we allow other | |
533 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
534 | */ |
535 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
536 | O_RDWR | O_CREAT, create_mode); | |
537 | if (wait_shm_fd >= 0) { | |
538 | ret = ftruncate(wait_shm_fd, mmap_size); | |
539 | if (ret) { | |
540 | PERROR("ftruncate"); | |
541 | exit(EXIT_FAILURE); | |
542 | } | |
58d4b2a2 MD |
543 | exit(EXIT_SUCCESS); |
544 | } | |
33bbeb90 MD |
545 | /* |
546 | * For local shm, we need to have rw access to accept | |
547 | * opening it: this means the local sessiond will be | |
548 | * able to wake us up. For global shm, we open it even | |
549 | * if rw access is not granted, because the root.root | |
550 | * sessiond will be able to override all rights and wake | |
551 | * us up. | |
552 | */ | |
553 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
554 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
555 | exit(EXIT_FAILURE); | |
556 | } | |
557 | /* | |
33bbeb90 MD |
558 | * The shm exists, but we cannot open it RW. Report |
559 | * success. | |
58d4b2a2 MD |
560 | */ |
561 | exit(EXIT_SUCCESS); | |
562 | } else { | |
563 | return -1; | |
7fc90dca | 564 | } |
58d4b2a2 | 565 | end: |
33bbeb90 MD |
566 | if (wait_shm_fd >= 0 && !sock_info->global) { |
567 | struct stat statbuf; | |
568 | ||
569 | /* | |
570 | * Ensure that our user is the owner of the shm file for | |
571 | * local shm. If we do not own the file, it means our | |
572 | * sessiond will not have access to wake us up (there is | |
573 | * probably a rogue process trying to fake our | |
574 | * sessiond). Fallback to polling method in this case. | |
575 | */ | |
576 | ret = fstat(wait_shm_fd, &statbuf); | |
577 | if (ret) { | |
578 | PERROR("fstat"); | |
579 | goto error_close; | |
580 | } | |
581 | if (statbuf.st_uid != getuid()) | |
582 | goto error_close; | |
583 | } | |
58d4b2a2 | 584 | return wait_shm_fd; |
33bbeb90 MD |
585 | |
586 | error_close: | |
587 | ret = close(wait_shm_fd); | |
588 | if (ret) { | |
589 | PERROR("Error closing fd"); | |
590 | } | |
591 | return -1; | |
58d4b2a2 MD |
592 | } |
593 | ||
594 | static | |
595 | char *get_map_shm(struct sock_info *sock_info) | |
596 | { | |
597 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
598 | int wait_shm_fd, ret; | |
599 | char *wait_shm_mmap; | |
600 | ||
601 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
602 | if (wait_shm_fd < 0) { | |
603 | goto error; | |
44e073f5 | 604 | } |
7fc90dca MD |
605 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
606 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
607 | /* close shm fd immediately after taking the mmap reference */ |
608 | ret = close(wait_shm_fd); | |
609 | if (ret) { | |
33bbeb90 MD |
610 | PERROR("Error closing fd"); |
611 | } | |
612 | if (wait_shm_mmap == MAP_FAILED) { | |
613 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
614 | goto error; | |
7fc90dca MD |
615 | } |
616 | return wait_shm_mmap; | |
617 | ||
618 | error: | |
619 | return NULL; | |
620 | } | |
621 | ||
622 | static | |
623 | void wait_for_sessiond(struct sock_info *sock_info) | |
624 | { | |
efe0de09 | 625 | int ret; |
80e2814b | 626 | |
7fc90dca MD |
627 | ust_lock(); |
628 | if (lttng_ust_comm_should_quit) { | |
629 | goto quit; | |
630 | } | |
37ed587a MD |
631 | if (wait_poll_fallback) { |
632 | goto error; | |
633 | } | |
7fc90dca MD |
634 | if (!sock_info->wait_shm_mmap) { |
635 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
636 | if (!sock_info->wait_shm_mmap) | |
637 | goto error; | |
638 | } | |
639 | ust_unlock(); | |
640 | ||
641 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
642 | /* Wait for futex wakeup */ |
643 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
644 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
645 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 646 | if (ret < 0) { |
37ed587a MD |
647 | if (errno == EFAULT) { |
648 | wait_poll_fallback = 1; | |
a8b870ad | 649 | DBG( |
37ed587a MD |
650 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
651 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
652 | "Please upgrade your kernel " | |
653 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
654 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
655 | if (ust_debug()) |
656 | PERROR("futex"); | |
37ed587a | 657 | } |
80e2814b MD |
658 | } |
659 | } | |
7fc90dca MD |
660 | return; |
661 | ||
662 | quit: | |
663 | ust_unlock(); | |
664 | return; | |
665 | ||
666 | error: | |
667 | ust_unlock(); | |
7fc90dca | 668 | return; |
46050b1a MD |
669 | } |
670 | ||
1ea11eab MD |
671 | /* |
672 | * This thread does not allocate any resource, except within | |
673 | * handle_message, within mutex protection. This mutex protects against | |
674 | * fork and exit. | |
675 | * The other moment it allocates resources is at socket connexion, which | |
676 | * is also protected by the mutex. | |
677 | */ | |
d9e99d10 MD |
678 | static |
679 | void *ust_listener_thread(void *arg) | |
680 | { | |
1ea11eab | 681 | struct sock_info *sock_info = arg; |
c0eedf81 | 682 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 683 | |
9eb62b9c MD |
684 | /* Restart trying to connect to the session daemon */ |
685 | restart: | |
c0eedf81 MD |
686 | if (prev_connect_failed) { |
687 | /* Wait for sessiond availability with pipe */ | |
688 | wait_for_sessiond(sock_info); | |
689 | if (has_waited) { | |
690 | has_waited = 0; | |
691 | /* | |
692 | * Sleep for 5 seconds before retrying after a | |
693 | * sequence of failure / wait / failure. This | |
694 | * deals with a killed or broken session daemon. | |
695 | */ | |
696 | sleep(5); | |
697 | } | |
698 | has_waited = 1; | |
699 | prev_connect_failed = 0; | |
700 | } | |
17dfb34b | 701 | ust_lock(); |
1ea11eab MD |
702 | |
703 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 704 | ust_unlock(); |
1ea11eab MD |
705 | goto quit; |
706 | } | |
9eb62b9c | 707 | |
1ea11eab | 708 | if (sock_info->socket != -1) { |
e6973a89 | 709 | ret = ustcomm_close_unix_sock(sock_info->socket); |
1ea11eab | 710 | if (ret) { |
11ff9c7d | 711 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
712 | } |
713 | sock_info->socket = -1; | |
714 | } | |
46050b1a | 715 | |
9eb62b9c | 716 | /* Register */ |
57773204 | 717 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 718 | if (ret < 0) { |
4d3c9523 | 719 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 720 | prev_connect_failed = 1; |
11ff9c7d MD |
721 | /* |
722 | * If we cannot find the sessiond daemon, don't delay | |
723 | * constructor execution. | |
724 | */ | |
edaa1431 | 725 | ret = handle_register_done(sock_info); |
11ff9c7d | 726 | assert(!ret); |
17dfb34b | 727 | ust_unlock(); |
1ea11eab | 728 | goto restart; |
46050b1a MD |
729 | } |
730 | ||
731 | sock_info->socket = sock = ret; | |
732 | ||
733 | /* | |
734 | * Create only one root handle per listener thread for the whole | |
735 | * process lifetime. | |
736 | */ | |
737 | if (sock_info->root_handle == -1) { | |
738 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 739 | if (ret < 0) { |
46050b1a | 740 | ERR("Error creating root handle"); |
17dfb34b | 741 | ust_unlock(); |
46050b1a MD |
742 | goto quit; |
743 | } | |
744 | sock_info->root_handle = ret; | |
9eb62b9c | 745 | } |
1ea11eab | 746 | |
9eb62b9c MD |
747 | ret = register_app_to_sessiond(sock); |
748 | if (ret < 0) { | |
11ff9c7d | 749 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 750 | prev_connect_failed = 1; |
11ff9c7d MD |
751 | /* |
752 | * If we cannot register to the sessiond daemon, don't | |
753 | * delay constructor execution. | |
754 | */ | |
edaa1431 | 755 | ret = handle_register_done(sock_info); |
11ff9c7d | 756 | assert(!ret); |
17dfb34b | 757 | ust_unlock(); |
9eb62b9c MD |
758 | goto restart; |
759 | } | |
17dfb34b | 760 | ust_unlock(); |
46050b1a | 761 | |
d9e99d10 MD |
762 | for (;;) { |
763 | ssize_t len; | |
57773204 | 764 | struct ustcomm_ust_msg lum; |
d9e99d10 | 765 | |
57773204 | 766 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
767 | switch (len) { |
768 | case 0: /* orderly shutdown */ | |
11ff9c7d | 769 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
770 | ust_lock(); |
771 | /* | |
772 | * Either sessiond has shutdown or refused us by closing the socket. | |
773 | * In either case, we don't want to delay construction execution, | |
774 | * and we need to wait before retry. | |
775 | */ | |
776 | prev_connect_failed = 1; | |
777 | /* | |
778 | * If we cannot register to the sessiond daemon, don't | |
779 | * delay constructor execution. | |
780 | */ | |
781 | ret = handle_register_done(sock_info); | |
782 | assert(!ret); | |
783 | ust_unlock(); | |
d9e99d10 | 784 | goto end; |
e7723462 | 785 | case sizeof(lum): |
d9e99d10 | 786 | DBG("message received\n"); |
11ff9c7d | 787 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 788 | if (ret < 0) { |
11ff9c7d | 789 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
790 | } |
791 | continue; | |
792 | case -1: | |
8236ba10 | 793 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 794 | if (errno == ECONNRESET) { |
11ff9c7d | 795 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
796 | goto end; |
797 | } | |
798 | goto end; | |
799 | default: | |
11ff9c7d | 800 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
801 | continue; |
802 | } | |
803 | ||
804 | } | |
805 | end: | |
9eb62b9c | 806 | goto restart; /* try to reconnect */ |
1ea11eab | 807 | quit: |
d9e99d10 MD |
808 | return NULL; |
809 | } | |
810 | ||
cf12a773 MD |
811 | /* |
812 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
813 | */ | |
11ff9c7d MD |
814 | static |
815 | int get_timeout(struct timespec *constructor_timeout) | |
816 | { | |
cf12a773 MD |
817 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
818 | char *str_delay; | |
11ff9c7d MD |
819 | int ret; |
820 | ||
69400ac4 | 821 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
822 | if (str_delay) { |
823 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
824 | } | |
825 | ||
826 | switch (constructor_delay_ms) { | |
827 | case -1:/* fall-through */ | |
828 | case 0: | |
829 | return constructor_delay_ms; | |
830 | default: | |
831 | break; | |
832 | } | |
833 | ||
834 | /* | |
835 | * If we are unable to find the current time, don't wait. | |
836 | */ | |
837 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
838 | if (ret) { | |
839 | return -1; | |
840 | } | |
95259bd0 MD |
841 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
842 | constructor_timeout->tv_nsec += | |
843 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
844 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
845 | constructor_timeout->tv_sec++; | |
846 | constructor_timeout->tv_nsec -= 1000000000UL; | |
847 | } | |
cf12a773 | 848 | return 1; |
11ff9c7d | 849 | } |
d9e99d10 | 850 | |
2691221a MD |
851 | /* |
852 | * sessiond monitoring thread: monitor presence of global and per-user | |
853 | * sessiond by polling the application common named pipe. | |
854 | */ | |
855 | /* TODO */ | |
856 | ||
edaa1431 | 857 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 858 | { |
11ff9c7d | 859 | struct timespec constructor_timeout; |
ae6a58bf | 860 | sigset_t sig_all_blocked, orig_parent_mask; |
cf12a773 | 861 | int timeout_mode; |
2691221a MD |
862 | int ret; |
863 | ||
edaa1431 MD |
864 | if (uatomic_xchg(&initialized, 1) == 1) |
865 | return; | |
866 | ||
eddd8d5d MD |
867 | /* |
868 | * Fixup interdependency between TLS fixup mutex (which happens | |
869 | * to be the dynamic linker mutex) and ust_lock, taken within | |
870 | * the ust lock. | |
871 | */ | |
872 | lttng_fixup_event_tls(); | |
f645cfa7 | 873 | lttng_fixup_ringbuffer_tls(); |
4158a15a | 874 | lttng_fixup_vtid_tls(); |
eddd8d5d | 875 | |
edaa1431 MD |
876 | /* |
877 | * We want precise control over the order in which we construct | |
878 | * our sub-libraries vs starting to receive commands from | |
879 | * sessiond (otherwise leading to errors when trying to create | |
880 | * sessiond before the init functions are completed). | |
881 | */ | |
2691221a | 882 | init_usterr(); |
edaa1431 MD |
883 | init_tracepoint(); |
884 | ltt_ring_buffer_metadata_client_init(); | |
885 | ltt_ring_buffer_client_overwrite_init(); | |
886 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 887 | |
cf12a773 | 888 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 889 | |
95259bd0 | 890 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
891 | assert(!ret); |
892 | ||
8d20bf54 | 893 | ret = setup_local_apps(); |
2691221a | 894 | if (ret) { |
8d20bf54 | 895 | ERR("Error setting up to local apps"); |
2691221a | 896 | } |
ae6a58bf WP |
897 | |
898 | /* A new thread created by pthread_create inherits the signal mask | |
899 | * from the parent. To avoid any signal being received by the | |
900 | * listener thread, we block all signals temporarily in the parent, | |
901 | * while we create the listener thread. | |
902 | */ | |
903 | sigfillset(&sig_all_blocked); | |
904 | ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask); | |
905 | if (ret) { | |
d94d802c | 906 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
907 | } |
908 | ||
dde70ea0 MD |
909 | ret = pthread_create(&global_apps.ust_listener, NULL, |
910 | ust_listener_thread, &global_apps); | |
d94d802c MD |
911 | if (ret) { |
912 | ERR("pthread_create global: %s", strerror(ret)); | |
913 | } | |
8d20bf54 | 914 | if (local_apps.allowed) { |
dde70ea0 MD |
915 | ret = pthread_create(&local_apps.ust_listener, NULL, |
916 | ust_listener_thread, &local_apps); | |
d94d802c MD |
917 | if (ret) { |
918 | ERR("pthread_create local: %s", strerror(ret)); | |
919 | } | |
8d20bf54 MD |
920 | } else { |
921 | handle_register_done(&local_apps); | |
922 | } | |
923 | ||
ae6a58bf WP |
924 | /* Restore original signal mask in parent */ |
925 | ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL); | |
926 | if (ret) { | |
d94d802c | 927 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
928 | } |
929 | ||
cf12a773 MD |
930 | switch (timeout_mode) { |
931 | case 1: /* timeout wait */ | |
95259bd0 MD |
932 | do { |
933 | ret = sem_timedwait(&constructor_wait, | |
934 | &constructor_timeout); | |
935 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
936 | if (ret < 0 && errno == ETIMEDOUT) { |
937 | ERR("Timed out waiting for ltt-sessiond"); | |
938 | } else { | |
939 | assert(!ret); | |
940 | } | |
941 | break; | |
7b766b16 | 942 | case -1:/* wait forever */ |
95259bd0 MD |
943 | do { |
944 | ret = sem_wait(&constructor_wait); | |
945 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 946 | assert(!ret); |
cf12a773 | 947 | break; |
7b766b16 | 948 | case 0: /* no timeout */ |
cf12a773 | 949 | break; |
11ff9c7d | 950 | } |
2691221a MD |
951 | } |
952 | ||
17dfb34b MD |
953 | static |
954 | void lttng_ust_cleanup(int exiting) | |
955 | { | |
efe0de09 | 956 | cleanup_sock_info(&global_apps, exiting); |
17dfb34b | 957 | if (local_apps.allowed) { |
efe0de09 | 958 | cleanup_sock_info(&local_apps, exiting); |
17dfb34b | 959 | } |
efe0de09 MD |
960 | /* |
961 | * The teardown in this function all affect data structures | |
962 | * accessed under the UST lock by the listener thread. This | |
963 | * lock, along with the lttng_ust_comm_should_quit flag, ensure | |
964 | * that none of these threads are accessing this data at this | |
965 | * point. | |
966 | */ | |
17dfb34b | 967 | lttng_ust_abi_exit(); |
003fedf4 | 968 | lttng_ust_events_exit(); |
17dfb34b MD |
969 | ltt_ring_buffer_client_discard_exit(); |
970 | ltt_ring_buffer_client_overwrite_exit(); | |
971 | ltt_ring_buffer_metadata_client_exit(); | |
972 | exit_tracepoint(); | |
973 | if (!exiting) { | |
974 | /* Reinitialize values for fork */ | |
975 | sem_count = 2; | |
976 | lttng_ust_comm_should_quit = 0; | |
977 | initialized = 0; | |
978 | } | |
979 | } | |
980 | ||
edaa1431 | 981 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
982 | { |
983 | int ret; | |
984 | ||
9eb62b9c MD |
985 | /* |
986 | * Using pthread_cancel here because: | |
987 | * A) we don't want to hang application teardown. | |
988 | * B) the thread is not allocating any resource. | |
989 | */ | |
1ea11eab MD |
990 | |
991 | /* | |
992 | * Require the communication thread to quit. Synchronize with | |
993 | * mutexes to ensure it is not in a mutex critical section when | |
994 | * pthread_cancel is later called. | |
995 | */ | |
17dfb34b | 996 | ust_lock(); |
1ea11eab | 997 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 998 | ust_unlock(); |
1ea11eab | 999 | |
f5f94532 | 1000 | /* cancel threads */ |
1ea11eab | 1001 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c | 1002 | if (ret) { |
d94d802c MD |
1003 | ERR("Error cancelling global ust listener thread: %s", |
1004 | strerror(ret)); | |
2691221a | 1005 | } |
8d20bf54 MD |
1006 | if (local_apps.allowed) { |
1007 | ret = pthread_cancel(local_apps.ust_listener); | |
1008 | if (ret) { | |
d94d802c MD |
1009 | ERR("Error cancelling local ust listener thread: %s", |
1010 | strerror(ret)); | |
8d20bf54 | 1011 | } |
8d20bf54 | 1012 | } |
efe0de09 MD |
1013 | /* |
1014 | * Do NOT join threads: use of sys_futex makes it impossible to | |
1015 | * join the threads without using async-cancel, but async-cancel | |
1016 | * is delivered by a signal, which could hit the target thread | |
1017 | * anywhere in its code path, including while the ust_lock() is | |
1018 | * held, causing a deadlock for the other thread. Let the OS | |
1019 | * cleanup the threads if there are stalled in a syscall. | |
1020 | */ | |
17dfb34b | 1021 | lttng_ust_cleanup(1); |
2691221a | 1022 | } |
e822f505 MD |
1023 | |
1024 | /* | |
1025 | * We exclude the worker threads across fork and clone (except | |
1026 | * CLONE_VM), because these system calls only keep the forking thread | |
1027 | * running in the child. Therefore, we don't want to call fork or clone | |
1028 | * in the middle of an tracepoint or ust tracing state modification. | |
1029 | * Holding this mutex protects these structures across fork and clone. | |
1030 | */ | |
b728d87e | 1031 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
1032 | { |
1033 | /* | |
1034 | * Disable signals. This is to avoid that the child intervenes | |
1035 | * before it is properly setup for tracing. It is safer to | |
1036 | * disable all signals, because then we know we are not breaking | |
1037 | * anything by restoring the original mask. | |
1038 | */ | |
1039 | sigset_t all_sigs; | |
1040 | int ret; | |
1041 | ||
e8508a49 MD |
1042 | if (lttng_ust_nest_count) |
1043 | return; | |
e822f505 MD |
1044 | /* Disable signals */ |
1045 | sigfillset(&all_sigs); | |
b728d87e | 1046 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
1047 | if (ret == -1) { |
1048 | PERROR("sigprocmask"); | |
1049 | } | |
17dfb34b | 1050 | ust_lock(); |
e822f505 MD |
1051 | rcu_bp_before_fork(); |
1052 | } | |
1053 | ||
b728d87e | 1054 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
1055 | { |
1056 | int ret; | |
1057 | ||
17dfb34b MD |
1058 | DBG("process %d", getpid()); |
1059 | ust_unlock(); | |
e822f505 | 1060 | /* Restore signals */ |
23c8854a | 1061 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
1062 | if (ret == -1) { |
1063 | PERROR("sigprocmask"); | |
1064 | } | |
1065 | } | |
1066 | ||
b728d87e | 1067 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 1068 | { |
e8508a49 MD |
1069 | if (lttng_ust_nest_count) |
1070 | return; | |
17dfb34b | 1071 | DBG("process %d", getpid()); |
e822f505 MD |
1072 | rcu_bp_after_fork_parent(); |
1073 | /* Release mutexes and reenable signals */ | |
b728d87e | 1074 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
1075 | } |
1076 | ||
17dfb34b MD |
1077 | /* |
1078 | * After fork, in the child, we need to cleanup all the leftover state, | |
1079 | * except the worker thread which already magically disappeared thanks | |
1080 | * to the weird Linux fork semantics. After tyding up, we call | |
1081 | * lttng_ust_init() again to start over as a new PID. | |
1082 | * | |
1083 | * This is meant for forks() that have tracing in the child between the | |
1084 | * fork and following exec call (if there is any). | |
1085 | */ | |
b728d87e | 1086 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 1087 | { |
e8508a49 MD |
1088 | if (lttng_ust_nest_count) |
1089 | return; | |
17dfb34b | 1090 | DBG("process %d", getpid()); |
e822f505 MD |
1091 | /* Release urcu mutexes */ |
1092 | rcu_bp_after_fork_child(); | |
17dfb34b | 1093 | lttng_ust_cleanup(0); |
a93bfc45 | 1094 | lttng_context_vtid_reset(); |
e822f505 | 1095 | /* Release mutexes and reenable signals */ |
b728d87e | 1096 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1097 | lttng_ust_init(); |
e822f505 | 1098 | } |