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 | ||
a903623f MD |
139 | /* |
140 | * Force a read (imply TLS fixup for dlopen) of TLS variables. | |
141 | */ | |
142 | static | |
143 | void lttng_fixup_nest_count_tls(void) | |
144 | { | |
145 | asm volatile ("" : : "m" (lttng_ust_nest_count)); | |
146 | } | |
147 | ||
2691221a | 148 | static |
8d20bf54 | 149 | int setup_local_apps(void) |
2691221a MD |
150 | { |
151 | const char *home_dir; | |
7fc90dca | 152 | uid_t uid; |
2691221a | 153 | |
7fc90dca | 154 | uid = getuid(); |
8d20bf54 MD |
155 | /* |
156 | * Disallow per-user tracing for setuid binaries. | |
157 | */ | |
7fc90dca | 158 | if (uid != geteuid()) { |
8d20bf54 | 159 | local_apps.allowed = 0; |
d0a1ae63 | 160 | return 0; |
8d20bf54 MD |
161 | } else { |
162 | local_apps.allowed = 1; | |
163 | } | |
2691221a MD |
164 | home_dir = (const char *) getenv("HOME"); |
165 | if (!home_dir) | |
166 | return -ENOENT; | |
1ea11eab | 167 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 168 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
169 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
170 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
171 | return 0; |
172 | } | |
173 | ||
174 | static | |
175 | int register_app_to_sessiond(int socket) | |
176 | { | |
177 | ssize_t ret; | |
178 | struct { | |
e44418f3 MD |
179 | uint32_t major; |
180 | uint32_t minor; | |
2691221a | 181 | pid_t pid; |
5c33bde8 | 182 | pid_t ppid; |
2691221a | 183 | uid_t uid; |
83610856 | 184 | gid_t gid; |
c117fb1b | 185 | uint32_t bits_per_long; |
2629549e | 186 | char name[16]; /* process name */ |
2691221a MD |
187 | } reg_msg; |
188 | ||
e44418f3 MD |
189 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
190 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 191 | reg_msg.pid = getpid(); |
5c33bde8 | 192 | reg_msg.ppid = getppid(); |
2691221a | 193 | reg_msg.uid = getuid(); |
83610856 | 194 | reg_msg.gid = getgid(); |
c117fb1b | 195 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
08114193 | 196 | lttng_ust_getprocname(reg_msg.name); |
2691221a | 197 | |
57773204 | 198 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
199 | if (ret >= 0 && ret != sizeof(reg_msg)) |
200 | return -EIO; | |
201 | return ret; | |
202 | } | |
203 | ||
d9e99d10 | 204 | static |
57773204 | 205 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 206 | { |
9eb62b9c | 207 | ssize_t len; |
d3a492d1 | 208 | |
57773204 | 209 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 210 | switch (len) { |
a4be8962 | 211 | case sizeof(*lur): |
d3a492d1 MD |
212 | DBG("message successfully sent"); |
213 | return 0; | |
214 | case -1: | |
215 | if (errno == ECONNRESET) { | |
216 | printf("remote end closed connection\n"); | |
217 | return 0; | |
218 | } | |
219 | return -1; | |
220 | default: | |
221 | printf("incorrect message size: %zd\n", len); | |
222 | return -1; | |
223 | } | |
224 | } | |
225 | ||
226 | static | |
edaa1431 | 227 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
228 | { |
229 | int ret; | |
230 | ||
edaa1431 MD |
231 | if (sock_info->constructor_sem_posted) |
232 | return 0; | |
233 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
234 | if (uatomic_read(&sem_count) <= 0) { |
235 | return 0; | |
236 | } | |
95259bd0 MD |
237 | ret = uatomic_add_return(&sem_count, -1); |
238 | if (ret == 0) { | |
239 | ret = sem_post(&constructor_wait); | |
240 | assert(!ret); | |
241 | } | |
11ff9c7d MD |
242 | return 0; |
243 | } | |
244 | ||
245 | static | |
246 | int handle_message(struct sock_info *sock_info, | |
57773204 | 247 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 248 | { |
1ea11eab | 249 | int ret = 0; |
b61ce3b2 | 250 | const struct lttng_ust_objd_ops *ops; |
57773204 | 251 | struct ustcomm_ust_reply lur; |
193183fb | 252 | int shm_fd, wait_fd; |
ef9ff354 | 253 | union ust_args args; |
40003310 | 254 | ssize_t len; |
1ea11eab | 255 | |
17dfb34b | 256 | ust_lock(); |
1ea11eab | 257 | |
46050b1a MD |
258 | memset(&lur, 0, sizeof(lur)); |
259 | ||
1ea11eab | 260 | if (lttng_ust_comm_should_quit) { |
46050b1a | 261 | ret = -EPERM; |
1ea11eab MD |
262 | goto end; |
263 | } | |
9eb62b9c | 264 | |
46050b1a MD |
265 | ops = objd_ops(lum->handle); |
266 | if (!ops) { | |
267 | ret = -ENOENT; | |
268 | goto end; | |
1ea11eab | 269 | } |
46050b1a MD |
270 | |
271 | switch (lum->cmd) { | |
11ff9c7d MD |
272 | case LTTNG_UST_REGISTER_DONE: |
273 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 274 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
275 | else |
276 | ret = -EINVAL; | |
277 | break; | |
46050b1a MD |
278 | case LTTNG_UST_RELEASE: |
279 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
280 | ret = -EPERM; | |
281 | else | |
d4419b81 | 282 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 MD |
283 | break; |
284 | default: | |
46050b1a MD |
285 | if (ops->cmd) |
286 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
287 | (unsigned long) &lum->u, |
288 | &args); | |
46050b1a MD |
289 | else |
290 | ret = -ENOSYS; | |
291 | break; | |
d9e99d10 | 292 | } |
46050b1a | 293 | |
1ea11eab | 294 | end: |
46050b1a MD |
295 | lur.handle = lum->handle; |
296 | lur.cmd = lum->cmd; | |
297 | lur.ret_val = ret; | |
298 | if (ret >= 0) { | |
57773204 | 299 | lur.ret_code = USTCOMM_OK; |
46050b1a | 300 | } else { |
57773204 | 301 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 302 | lur.ret_code = ret; |
46050b1a | 303 | } |
e6ea14c5 MD |
304 | if (ret >= 0) { |
305 | switch (lum->cmd) { | |
306 | case LTTNG_UST_STREAM: | |
307 | /* | |
308 | * Special-case reply to send stream info. | |
309 | * Use lum.u output. | |
310 | */ | |
311 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; | |
312 | shm_fd = *args.stream.shm_fd; | |
313 | wait_fd = *args.stream.wait_fd; | |
314 | break; | |
315 | case LTTNG_UST_METADATA: | |
316 | case LTTNG_UST_CHANNEL: | |
317 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; | |
318 | shm_fd = *args.channel.shm_fd; | |
319 | wait_fd = *args.channel.wait_fd; | |
320 | break; | |
321 | case LTTNG_UST_TRACER_VERSION: | |
322 | lur.u.version = lum->u.version; | |
323 | break; | |
324 | case LTTNG_UST_TRACEPOINT_LIST_GET: | |
325 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); | |
326 | break; | |
327 | } | |
381c0f1e | 328 | } |
46050b1a | 329 | ret = send_reply(sock, &lur); |
193183fb MD |
330 | if (ret < 0) { |
331 | perror("error sending reply"); | |
332 | goto error; | |
333 | } | |
46050b1a | 334 | |
824f40b8 MD |
335 | if ((lum->cmd == LTTNG_UST_STREAM |
336 | || lum->cmd == LTTNG_UST_CHANNEL | |
337 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 338 | && lur.ret_code == USTCOMM_OK) { |
50be2fc4 MD |
339 | int sendret = 0; |
340 | ||
381c0f1e | 341 | /* we also need to send the file descriptors. */ |
57773204 | 342 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 343 | &shm_fd, &shm_fd, |
381c0f1e MD |
344 | 1, sizeof(int)); |
345 | if (ret < 0) { | |
346 | perror("send shm_fd"); | |
50be2fc4 | 347 | sendret = ret; |
381c0f1e | 348 | } |
50be2fc4 MD |
349 | /* |
350 | * The sessiond expects 2 file descriptors, even upon | |
351 | * error. | |
352 | */ | |
57773204 | 353 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 354 | &wait_fd, &wait_fd, |
381c0f1e MD |
355 | 1, sizeof(int)); |
356 | if (ret < 0) { | |
357 | perror("send wait_fd"); | |
358 | goto error; | |
359 | } | |
50be2fc4 MD |
360 | if (sendret) { |
361 | ret = sendret; | |
362 | goto error; | |
363 | } | |
381c0f1e | 364 | } |
40003310 MD |
365 | /* |
366 | * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field | |
367 | * after the reply. | |
368 | */ | |
369 | if (lur.ret_code == USTCOMM_OK) { | |
370 | switch (lum->cmd) { | |
371 | case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET: | |
372 | len = ustcomm_send_unix_sock(sock, | |
373 | &args.field_list.entry, | |
374 | sizeof(args.field_list.entry)); | |
375 | if (len != sizeof(args.field_list.entry)) { | |
376 | ret = -1; | |
377 | goto error; | |
378 | } | |
379 | } | |
380 | } | |
ef9ff354 MD |
381 | /* |
382 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
383 | * sent to the sessiond. We can therefore close those fds. Note |
384 | * that we keep the write side of the wait_fd open, but close | |
385 | * the read side. | |
ef9ff354 MD |
386 | */ |
387 | if (lur.ret_code == USTCOMM_OK) { | |
388 | switch (lum->cmd) { | |
389 | case LTTNG_UST_STREAM: | |
390 | if (shm_fd >= 0) { | |
391 | ret = close(shm_fd); | |
392 | if (ret) { | |
393 | PERROR("Error closing stream shm_fd"); | |
394 | } | |
395 | *args.stream.shm_fd = -1; | |
396 | } | |
397 | if (wait_fd >= 0) { | |
398 | ret = close(wait_fd); | |
399 | if (ret) { | |
400 | PERROR("Error closing stream wait_fd"); | |
401 | } | |
402 | *args.stream.wait_fd = -1; | |
403 | } | |
404 | break; | |
405 | case LTTNG_UST_METADATA: | |
406 | case LTTNG_UST_CHANNEL: | |
407 | if (shm_fd >= 0) { | |
408 | ret = close(shm_fd); | |
409 | if (ret) { | |
410 | PERROR("Error closing channel shm_fd"); | |
411 | } | |
412 | *args.channel.shm_fd = -1; | |
413 | } | |
414 | if (wait_fd >= 0) { | |
415 | ret = close(wait_fd); | |
416 | if (ret) { | |
417 | PERROR("Error closing channel wait_fd"); | |
418 | } | |
419 | *args.channel.wait_fd = -1; | |
420 | } | |
421 | break; | |
422 | } | |
423 | } | |
424 | ||
381c0f1e | 425 | error: |
17dfb34b | 426 | ust_unlock(); |
1ea11eab | 427 | return ret; |
d9e99d10 MD |
428 | } |
429 | ||
46050b1a | 430 | static |
efe0de09 | 431 | void cleanup_sock_info(struct sock_info *sock_info, int exiting) |
46050b1a MD |
432 | { |
433 | int ret; | |
434 | ||
435 | if (sock_info->socket != -1) { | |
e6973a89 | 436 | ret = ustcomm_close_unix_sock(sock_info->socket); |
46050b1a | 437 | if (ret) { |
7fc90dca | 438 | ERR("Error closing apps socket"); |
46050b1a MD |
439 | } |
440 | sock_info->socket = -1; | |
441 | } | |
442 | if (sock_info->root_handle != -1) { | |
d4419b81 | 443 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
444 | if (ret) { |
445 | ERR("Error unref root handle"); | |
446 | } | |
447 | sock_info->root_handle = -1; | |
448 | } | |
318dfea9 | 449 | sock_info->constructor_sem_posted = 0; |
efe0de09 MD |
450 | /* |
451 | * wait_shm_mmap is used by listener threads outside of the | |
452 | * ust lock, so we cannot tear it down ourselves, because we | |
453 | * cannot join on these threads. Leave this task to the OS | |
454 | * process exit. | |
455 | */ | |
456 | if (!exiting && sock_info->wait_shm_mmap) { | |
7fc90dca MD |
457 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); |
458 | if (ret) { | |
459 | ERR("Error unmapping wait shm"); | |
460 | } | |
461 | sock_info->wait_shm_mmap = NULL; | |
462 | } | |
463 | } | |
464 | ||
58d4b2a2 | 465 | /* |
33bbeb90 MD |
466 | * Using fork to set umask in the child process (not multi-thread safe). |
467 | * We deal with the shm_open vs ftruncate race (happening when the | |
468 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
469 | * safety against shm_unlink) by simply letting the mmap fail and | |
470 | * retrying after a few seconds. | |
471 | * For global shm, everybody has rw access to it until the sessiond | |
472 | * starts. | |
58d4b2a2 | 473 | */ |
7fc90dca | 474 | static |
58d4b2a2 | 475 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 476 | { |
7fc90dca | 477 | int wait_shm_fd, ret; |
58d4b2a2 | 478 | pid_t pid; |
44e073f5 | 479 | |
58d4b2a2 | 480 | /* |
33bbeb90 | 481 | * Try to open read-only. |
58d4b2a2 | 482 | */ |
33bbeb90 | 483 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
484 | if (wait_shm_fd >= 0) { |
485 | goto end; | |
486 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
487 | /* | |
33bbeb90 MD |
488 | * Real-only open did not work, and it's not because the |
489 | * entry was not present. It's a failure that prohibits | |
490 | * using shm. | |
58d4b2a2 | 491 | */ |
7fc90dca | 492 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 493 | goto end; |
7fc90dca MD |
494 | } |
495 | /* | |
58d4b2a2 MD |
496 | * If the open failed because the file did not exist, try |
497 | * creating it ourself. | |
7fc90dca | 498 | */ |
e8508a49 | 499 | lttng_ust_nest_count++; |
58d4b2a2 | 500 | pid = fork(); |
e8508a49 | 501 | lttng_ust_nest_count--; |
58d4b2a2 MD |
502 | if (pid > 0) { |
503 | int status; | |
504 | ||
505 | /* | |
506 | * Parent: wait for child to return, in which case the | |
507 | * shared memory map will have been created. | |
508 | */ | |
509 | pid = wait(&status); | |
b7d3cb32 | 510 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
511 | wait_shm_fd = -1; |
512 | goto end; | |
7fc90dca | 513 | } |
58d4b2a2 MD |
514 | /* |
515 | * Try to open read-only again after creation. | |
516 | */ | |
33bbeb90 | 517 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
518 | if (wait_shm_fd < 0) { |
519 | /* | |
520 | * Real-only open did not work. It's a failure | |
521 | * that prohibits using shm. | |
522 | */ | |
523 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
524 | goto end; | |
525 | } | |
526 | goto end; | |
527 | } else if (pid == 0) { | |
528 | int create_mode; | |
529 | ||
530 | /* Child */ | |
33bbeb90 | 531 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 532 | if (sock_info->global) |
33bbeb90 | 533 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
534 | /* |
535 | * We're alone in a child process, so we can modify the | |
536 | * process-wide umask. | |
537 | */ | |
33bbeb90 | 538 | umask(~create_mode); |
58d4b2a2 | 539 | /* |
33bbeb90 MD |
540 | * Try creating shm (or get rw access). |
541 | * We don't do an exclusive open, because we allow other | |
542 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
543 | */ |
544 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
545 | O_RDWR | O_CREAT, create_mode); | |
546 | if (wait_shm_fd >= 0) { | |
547 | ret = ftruncate(wait_shm_fd, mmap_size); | |
548 | if (ret) { | |
549 | PERROR("ftruncate"); | |
550 | exit(EXIT_FAILURE); | |
551 | } | |
58d4b2a2 MD |
552 | exit(EXIT_SUCCESS); |
553 | } | |
33bbeb90 MD |
554 | /* |
555 | * For local shm, we need to have rw access to accept | |
556 | * opening it: this means the local sessiond will be | |
557 | * able to wake us up. For global shm, we open it even | |
558 | * if rw access is not granted, because the root.root | |
559 | * sessiond will be able to override all rights and wake | |
560 | * us up. | |
561 | */ | |
562 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
563 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
564 | exit(EXIT_FAILURE); | |
565 | } | |
566 | /* | |
33bbeb90 MD |
567 | * The shm exists, but we cannot open it RW. Report |
568 | * success. | |
58d4b2a2 MD |
569 | */ |
570 | exit(EXIT_SUCCESS); | |
571 | } else { | |
572 | return -1; | |
7fc90dca | 573 | } |
58d4b2a2 | 574 | end: |
33bbeb90 MD |
575 | if (wait_shm_fd >= 0 && !sock_info->global) { |
576 | struct stat statbuf; | |
577 | ||
578 | /* | |
579 | * Ensure that our user is the owner of the shm file for | |
580 | * local shm. If we do not own the file, it means our | |
581 | * sessiond will not have access to wake us up (there is | |
582 | * probably a rogue process trying to fake our | |
583 | * sessiond). Fallback to polling method in this case. | |
584 | */ | |
585 | ret = fstat(wait_shm_fd, &statbuf); | |
586 | if (ret) { | |
587 | PERROR("fstat"); | |
588 | goto error_close; | |
589 | } | |
590 | if (statbuf.st_uid != getuid()) | |
591 | goto error_close; | |
592 | } | |
58d4b2a2 | 593 | return wait_shm_fd; |
33bbeb90 MD |
594 | |
595 | error_close: | |
596 | ret = close(wait_shm_fd); | |
597 | if (ret) { | |
598 | PERROR("Error closing fd"); | |
599 | } | |
600 | return -1; | |
58d4b2a2 MD |
601 | } |
602 | ||
603 | static | |
604 | char *get_map_shm(struct sock_info *sock_info) | |
605 | { | |
606 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
607 | int wait_shm_fd, ret; | |
608 | char *wait_shm_mmap; | |
609 | ||
610 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
611 | if (wait_shm_fd < 0) { | |
612 | goto error; | |
44e073f5 | 613 | } |
7fc90dca MD |
614 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
615 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
616 | /* close shm fd immediately after taking the mmap reference */ |
617 | ret = close(wait_shm_fd); | |
618 | if (ret) { | |
33bbeb90 MD |
619 | PERROR("Error closing fd"); |
620 | } | |
621 | if (wait_shm_mmap == MAP_FAILED) { | |
622 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
623 | goto error; | |
7fc90dca MD |
624 | } |
625 | return wait_shm_mmap; | |
626 | ||
627 | error: | |
628 | return NULL; | |
629 | } | |
630 | ||
631 | static | |
632 | void wait_for_sessiond(struct sock_info *sock_info) | |
633 | { | |
efe0de09 | 634 | int ret; |
80e2814b | 635 | |
7fc90dca MD |
636 | ust_lock(); |
637 | if (lttng_ust_comm_should_quit) { | |
638 | goto quit; | |
639 | } | |
37ed587a MD |
640 | if (wait_poll_fallback) { |
641 | goto error; | |
642 | } | |
7fc90dca MD |
643 | if (!sock_info->wait_shm_mmap) { |
644 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
645 | if (!sock_info->wait_shm_mmap) | |
646 | goto error; | |
647 | } | |
648 | ust_unlock(); | |
649 | ||
650 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
651 | /* Wait for futex wakeup */ |
652 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
653 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
654 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 655 | if (ret < 0) { |
37ed587a MD |
656 | if (errno == EFAULT) { |
657 | wait_poll_fallback = 1; | |
a8b870ad | 658 | DBG( |
37ed587a MD |
659 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
660 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
661 | "Please upgrade your kernel " | |
662 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
663 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
664 | if (ust_debug()) |
665 | PERROR("futex"); | |
37ed587a | 666 | } |
80e2814b MD |
667 | } |
668 | } | |
7fc90dca MD |
669 | return; |
670 | ||
671 | quit: | |
672 | ust_unlock(); | |
673 | return; | |
674 | ||
675 | error: | |
676 | ust_unlock(); | |
7fc90dca | 677 | return; |
46050b1a MD |
678 | } |
679 | ||
1ea11eab MD |
680 | /* |
681 | * This thread does not allocate any resource, except within | |
682 | * handle_message, within mutex protection. This mutex protects against | |
683 | * fork and exit. | |
684 | * The other moment it allocates resources is at socket connexion, which | |
685 | * is also protected by the mutex. | |
686 | */ | |
d9e99d10 MD |
687 | static |
688 | void *ust_listener_thread(void *arg) | |
689 | { | |
1ea11eab | 690 | struct sock_info *sock_info = arg; |
c0eedf81 | 691 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 692 | |
9eb62b9c MD |
693 | /* Restart trying to connect to the session daemon */ |
694 | restart: | |
c0eedf81 MD |
695 | if (prev_connect_failed) { |
696 | /* Wait for sessiond availability with pipe */ | |
697 | wait_for_sessiond(sock_info); | |
698 | if (has_waited) { | |
699 | has_waited = 0; | |
700 | /* | |
701 | * Sleep for 5 seconds before retrying after a | |
702 | * sequence of failure / wait / failure. This | |
703 | * deals with a killed or broken session daemon. | |
704 | */ | |
705 | sleep(5); | |
706 | } | |
707 | has_waited = 1; | |
708 | prev_connect_failed = 0; | |
709 | } | |
17dfb34b | 710 | ust_lock(); |
1ea11eab MD |
711 | |
712 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 713 | ust_unlock(); |
1ea11eab MD |
714 | goto quit; |
715 | } | |
9eb62b9c | 716 | |
1ea11eab | 717 | if (sock_info->socket != -1) { |
e6973a89 | 718 | ret = ustcomm_close_unix_sock(sock_info->socket); |
1ea11eab | 719 | if (ret) { |
11ff9c7d | 720 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
721 | } |
722 | sock_info->socket = -1; | |
723 | } | |
46050b1a | 724 | |
9eb62b9c | 725 | /* Register */ |
57773204 | 726 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 727 | if (ret < 0) { |
4d3c9523 | 728 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 729 | prev_connect_failed = 1; |
11ff9c7d MD |
730 | /* |
731 | * If we cannot find the sessiond daemon, don't delay | |
732 | * constructor execution. | |
733 | */ | |
edaa1431 | 734 | ret = handle_register_done(sock_info); |
11ff9c7d | 735 | assert(!ret); |
17dfb34b | 736 | ust_unlock(); |
1ea11eab | 737 | goto restart; |
46050b1a MD |
738 | } |
739 | ||
740 | sock_info->socket = sock = ret; | |
741 | ||
742 | /* | |
743 | * Create only one root handle per listener thread for the whole | |
744 | * process lifetime. | |
745 | */ | |
746 | if (sock_info->root_handle == -1) { | |
747 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 748 | if (ret < 0) { |
46050b1a | 749 | ERR("Error creating root handle"); |
17dfb34b | 750 | ust_unlock(); |
46050b1a MD |
751 | goto quit; |
752 | } | |
753 | sock_info->root_handle = ret; | |
9eb62b9c | 754 | } |
1ea11eab | 755 | |
9eb62b9c MD |
756 | ret = register_app_to_sessiond(sock); |
757 | if (ret < 0) { | |
11ff9c7d | 758 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 759 | prev_connect_failed = 1; |
11ff9c7d MD |
760 | /* |
761 | * If we cannot register to the sessiond daemon, don't | |
762 | * delay constructor execution. | |
763 | */ | |
edaa1431 | 764 | ret = handle_register_done(sock_info); |
11ff9c7d | 765 | assert(!ret); |
17dfb34b | 766 | ust_unlock(); |
9eb62b9c MD |
767 | goto restart; |
768 | } | |
17dfb34b | 769 | ust_unlock(); |
46050b1a | 770 | |
d9e99d10 MD |
771 | for (;;) { |
772 | ssize_t len; | |
57773204 | 773 | struct ustcomm_ust_msg lum; |
d9e99d10 | 774 | |
57773204 | 775 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
776 | switch (len) { |
777 | case 0: /* orderly shutdown */ | |
11ff9c7d | 778 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
779 | ust_lock(); |
780 | /* | |
781 | * Either sessiond has shutdown or refused us by closing the socket. | |
782 | * In either case, we don't want to delay construction execution, | |
783 | * and we need to wait before retry. | |
784 | */ | |
785 | prev_connect_failed = 1; | |
786 | /* | |
787 | * If we cannot register to the sessiond daemon, don't | |
788 | * delay constructor execution. | |
789 | */ | |
790 | ret = handle_register_done(sock_info); | |
791 | assert(!ret); | |
792 | ust_unlock(); | |
d9e99d10 | 793 | goto end; |
e7723462 | 794 | case sizeof(lum): |
d9e99d10 | 795 | DBG("message received\n"); |
11ff9c7d | 796 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 797 | if (ret < 0) { |
11ff9c7d | 798 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
799 | } |
800 | continue; | |
801 | case -1: | |
8236ba10 | 802 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 803 | if (errno == ECONNRESET) { |
11ff9c7d | 804 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
805 | goto end; |
806 | } | |
807 | goto end; | |
808 | default: | |
11ff9c7d | 809 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
810 | continue; |
811 | } | |
812 | ||
813 | } | |
814 | end: | |
9eb62b9c | 815 | goto restart; /* try to reconnect */ |
1ea11eab | 816 | quit: |
d9e99d10 MD |
817 | return NULL; |
818 | } | |
819 | ||
cf12a773 MD |
820 | /* |
821 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
822 | */ | |
11ff9c7d MD |
823 | static |
824 | int get_timeout(struct timespec *constructor_timeout) | |
825 | { | |
cf12a773 MD |
826 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
827 | char *str_delay; | |
11ff9c7d MD |
828 | int ret; |
829 | ||
69400ac4 | 830 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
831 | if (str_delay) { |
832 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
833 | } | |
834 | ||
835 | switch (constructor_delay_ms) { | |
836 | case -1:/* fall-through */ | |
837 | case 0: | |
838 | return constructor_delay_ms; | |
839 | default: | |
840 | break; | |
841 | } | |
842 | ||
843 | /* | |
844 | * If we are unable to find the current time, don't wait. | |
845 | */ | |
846 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
847 | if (ret) { | |
848 | return -1; | |
849 | } | |
95259bd0 MD |
850 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
851 | constructor_timeout->tv_nsec += | |
852 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
853 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
854 | constructor_timeout->tv_sec++; | |
855 | constructor_timeout->tv_nsec -= 1000000000UL; | |
856 | } | |
cf12a773 | 857 | return 1; |
11ff9c7d | 858 | } |
d9e99d10 | 859 | |
2691221a MD |
860 | /* |
861 | * sessiond monitoring thread: monitor presence of global and per-user | |
862 | * sessiond by polling the application common named pipe. | |
863 | */ | |
864 | /* TODO */ | |
865 | ||
edaa1431 | 866 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 867 | { |
11ff9c7d | 868 | struct timespec constructor_timeout; |
ae6a58bf | 869 | sigset_t sig_all_blocked, orig_parent_mask; |
cf12a773 | 870 | int timeout_mode; |
2691221a MD |
871 | int ret; |
872 | ||
edaa1431 MD |
873 | if (uatomic_xchg(&initialized, 1) == 1) |
874 | return; | |
875 | ||
eddd8d5d MD |
876 | /* |
877 | * Fixup interdependency between TLS fixup mutex (which happens | |
878 | * to be the dynamic linker mutex) and ust_lock, taken within | |
879 | * the ust lock. | |
880 | */ | |
881 | lttng_fixup_event_tls(); | |
f645cfa7 | 882 | lttng_fixup_ringbuffer_tls(); |
4158a15a | 883 | lttng_fixup_vtid_tls(); |
a903623f | 884 | lttng_fixup_nest_count_tls(); |
eddd8d5d | 885 | |
edaa1431 MD |
886 | /* |
887 | * We want precise control over the order in which we construct | |
888 | * our sub-libraries vs starting to receive commands from | |
889 | * sessiond (otherwise leading to errors when trying to create | |
890 | * sessiond before the init functions are completed). | |
891 | */ | |
2691221a | 892 | init_usterr(); |
edaa1431 MD |
893 | init_tracepoint(); |
894 | ltt_ring_buffer_metadata_client_init(); | |
895 | ltt_ring_buffer_client_overwrite_init(); | |
896 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 897 | |
cf12a773 | 898 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 899 | |
95259bd0 | 900 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
901 | assert(!ret); |
902 | ||
8d20bf54 | 903 | ret = setup_local_apps(); |
2691221a | 904 | if (ret) { |
8d20bf54 | 905 | ERR("Error setting up to local apps"); |
2691221a | 906 | } |
ae6a58bf WP |
907 | |
908 | /* A new thread created by pthread_create inherits the signal mask | |
909 | * from the parent. To avoid any signal being received by the | |
910 | * listener thread, we block all signals temporarily in the parent, | |
911 | * while we create the listener thread. | |
912 | */ | |
913 | sigfillset(&sig_all_blocked); | |
914 | ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask); | |
915 | if (ret) { | |
d94d802c | 916 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
917 | } |
918 | ||
dde70ea0 MD |
919 | ret = pthread_create(&global_apps.ust_listener, NULL, |
920 | ust_listener_thread, &global_apps); | |
d94d802c MD |
921 | if (ret) { |
922 | ERR("pthread_create global: %s", strerror(ret)); | |
923 | } | |
8d20bf54 | 924 | if (local_apps.allowed) { |
dde70ea0 MD |
925 | ret = pthread_create(&local_apps.ust_listener, NULL, |
926 | ust_listener_thread, &local_apps); | |
d94d802c MD |
927 | if (ret) { |
928 | ERR("pthread_create local: %s", strerror(ret)); | |
929 | } | |
8d20bf54 MD |
930 | } else { |
931 | handle_register_done(&local_apps); | |
932 | } | |
933 | ||
ae6a58bf WP |
934 | /* Restore original signal mask in parent */ |
935 | ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL); | |
936 | if (ret) { | |
d94d802c | 937 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
938 | } |
939 | ||
cf12a773 MD |
940 | switch (timeout_mode) { |
941 | case 1: /* timeout wait */ | |
95259bd0 MD |
942 | do { |
943 | ret = sem_timedwait(&constructor_wait, | |
944 | &constructor_timeout); | |
945 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
946 | if (ret < 0 && errno == ETIMEDOUT) { |
947 | ERR("Timed out waiting for ltt-sessiond"); | |
948 | } else { | |
949 | assert(!ret); | |
950 | } | |
951 | break; | |
7b766b16 | 952 | case -1:/* wait forever */ |
95259bd0 MD |
953 | do { |
954 | ret = sem_wait(&constructor_wait); | |
955 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 956 | assert(!ret); |
cf12a773 | 957 | break; |
7b766b16 | 958 | case 0: /* no timeout */ |
cf12a773 | 959 | break; |
11ff9c7d | 960 | } |
2691221a MD |
961 | } |
962 | ||
17dfb34b MD |
963 | static |
964 | void lttng_ust_cleanup(int exiting) | |
965 | { | |
efe0de09 | 966 | cleanup_sock_info(&global_apps, exiting); |
17dfb34b | 967 | if (local_apps.allowed) { |
efe0de09 | 968 | cleanup_sock_info(&local_apps, exiting); |
17dfb34b | 969 | } |
efe0de09 MD |
970 | /* |
971 | * The teardown in this function all affect data structures | |
972 | * accessed under the UST lock by the listener thread. This | |
973 | * lock, along with the lttng_ust_comm_should_quit flag, ensure | |
974 | * that none of these threads are accessing this data at this | |
975 | * point. | |
976 | */ | |
17dfb34b | 977 | lttng_ust_abi_exit(); |
003fedf4 | 978 | lttng_ust_events_exit(); |
17dfb34b MD |
979 | ltt_ring_buffer_client_discard_exit(); |
980 | ltt_ring_buffer_client_overwrite_exit(); | |
981 | ltt_ring_buffer_metadata_client_exit(); | |
982 | exit_tracepoint(); | |
983 | if (!exiting) { | |
984 | /* Reinitialize values for fork */ | |
985 | sem_count = 2; | |
986 | lttng_ust_comm_should_quit = 0; | |
987 | initialized = 0; | |
988 | } | |
989 | } | |
990 | ||
edaa1431 | 991 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
992 | { |
993 | int ret; | |
994 | ||
9eb62b9c MD |
995 | /* |
996 | * Using pthread_cancel here because: | |
997 | * A) we don't want to hang application teardown. | |
998 | * B) the thread is not allocating any resource. | |
999 | */ | |
1ea11eab MD |
1000 | |
1001 | /* | |
1002 | * Require the communication thread to quit. Synchronize with | |
1003 | * mutexes to ensure it is not in a mutex critical section when | |
1004 | * pthread_cancel is later called. | |
1005 | */ | |
17dfb34b | 1006 | ust_lock(); |
1ea11eab | 1007 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 1008 | ust_unlock(); |
1ea11eab | 1009 | |
f5f94532 | 1010 | /* cancel threads */ |
1ea11eab | 1011 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c | 1012 | if (ret) { |
d94d802c MD |
1013 | ERR("Error cancelling global ust listener thread: %s", |
1014 | strerror(ret)); | |
2691221a | 1015 | } |
8d20bf54 MD |
1016 | if (local_apps.allowed) { |
1017 | ret = pthread_cancel(local_apps.ust_listener); | |
1018 | if (ret) { | |
d94d802c MD |
1019 | ERR("Error cancelling local ust listener thread: %s", |
1020 | strerror(ret)); | |
8d20bf54 | 1021 | } |
8d20bf54 | 1022 | } |
efe0de09 MD |
1023 | /* |
1024 | * Do NOT join threads: use of sys_futex makes it impossible to | |
1025 | * join the threads without using async-cancel, but async-cancel | |
1026 | * is delivered by a signal, which could hit the target thread | |
1027 | * anywhere in its code path, including while the ust_lock() is | |
1028 | * held, causing a deadlock for the other thread. Let the OS | |
1029 | * cleanup the threads if there are stalled in a syscall. | |
1030 | */ | |
17dfb34b | 1031 | lttng_ust_cleanup(1); |
2691221a | 1032 | } |
e822f505 MD |
1033 | |
1034 | /* | |
1035 | * We exclude the worker threads across fork and clone (except | |
1036 | * CLONE_VM), because these system calls only keep the forking thread | |
1037 | * running in the child. Therefore, we don't want to call fork or clone | |
1038 | * in the middle of an tracepoint or ust tracing state modification. | |
1039 | * Holding this mutex protects these structures across fork and clone. | |
1040 | */ | |
b728d87e | 1041 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
1042 | { |
1043 | /* | |
1044 | * Disable signals. This is to avoid that the child intervenes | |
1045 | * before it is properly setup for tracing. It is safer to | |
1046 | * disable all signals, because then we know we are not breaking | |
1047 | * anything by restoring the original mask. | |
1048 | */ | |
1049 | sigset_t all_sigs; | |
1050 | int ret; | |
1051 | ||
e8508a49 MD |
1052 | if (lttng_ust_nest_count) |
1053 | return; | |
e822f505 MD |
1054 | /* Disable signals */ |
1055 | sigfillset(&all_sigs); | |
b728d87e | 1056 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
1057 | if (ret == -1) { |
1058 | PERROR("sigprocmask"); | |
1059 | } | |
17dfb34b | 1060 | ust_lock(); |
e822f505 MD |
1061 | rcu_bp_before_fork(); |
1062 | } | |
1063 | ||
b728d87e | 1064 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
1065 | { |
1066 | int ret; | |
1067 | ||
17dfb34b MD |
1068 | DBG("process %d", getpid()); |
1069 | ust_unlock(); | |
e822f505 | 1070 | /* Restore signals */ |
23c8854a | 1071 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
1072 | if (ret == -1) { |
1073 | PERROR("sigprocmask"); | |
1074 | } | |
1075 | } | |
1076 | ||
b728d87e | 1077 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 1078 | { |
e8508a49 MD |
1079 | if (lttng_ust_nest_count) |
1080 | return; | |
17dfb34b | 1081 | DBG("process %d", getpid()); |
e822f505 MD |
1082 | rcu_bp_after_fork_parent(); |
1083 | /* Release mutexes and reenable signals */ | |
b728d87e | 1084 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
1085 | } |
1086 | ||
17dfb34b MD |
1087 | /* |
1088 | * After fork, in the child, we need to cleanup all the leftover state, | |
1089 | * except the worker thread which already magically disappeared thanks | |
1090 | * to the weird Linux fork semantics. After tyding up, we call | |
1091 | * lttng_ust_init() again to start over as a new PID. | |
1092 | * | |
1093 | * This is meant for forks() that have tracing in the child between the | |
1094 | * fork and following exec call (if there is any). | |
1095 | */ | |
b728d87e | 1096 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 1097 | { |
e8508a49 MD |
1098 | if (lttng_ust_nest_count) |
1099 | return; | |
17dfb34b | 1100 | DBG("process %d", getpid()); |
e822f505 MD |
1101 | /* Release urcu mutexes */ |
1102 | rcu_bp_after_fork_child(); | |
17dfb34b | 1103 | lttng_ust_cleanup(0); |
a93bfc45 | 1104 | lttng_context_vtid_reset(); |
e822f505 | 1105 | /* Release mutexes and reenable signals */ |
b728d87e | 1106 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1107 | lttng_ust_init(); |
e822f505 | 1108 | } |