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