Commit | Line | Data |
---|---|---|
2691221a MD |
1 | /* |
2 | * lttng-ust-comm.c | |
3 | * | |
4 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> | |
5 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
6 | * | |
7 | * This library is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU Lesser General Public | |
9 | * License as published by the Free Software Foundation; only | |
10 | * version 2.1 of the License. | |
11 | * | |
12 | * This library is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with this library; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | #include <sys/types.h> | |
23 | #include <sys/socket.h> | |
2629549e | 24 | #include <sys/prctl.h> |
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> |
1ea11eab | 38 | |
edaa1431 MD |
39 | #include <lttng-ust-comm.h> |
40 | #include <ust/usterr-signal-safe.h> | |
41 | #include <ust/lttng-ust-abi.h> | |
42 | #include <ust/tracepoint.h> | |
d0a1ae63 | 43 | #include <ust/tracepoint-internal.h> |
e822f505 | 44 | #include <ust/ust.h> |
b751f722 | 45 | #include "ltt-tracer-core.h" |
edaa1431 MD |
46 | |
47 | /* | |
48 | * Has lttng ust comm constructor been called ? | |
49 | */ | |
50 | static int initialized; | |
51 | ||
1ea11eab | 52 | /* |
17dfb34b MD |
53 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
54 | * Held when handling a command, also held by fork() to deal with | |
55 | * removal of threads, and by exit path. | |
1ea11eab | 56 | */ |
1ea11eab MD |
57 | |
58 | /* Should the ust comm thread quit ? */ | |
59 | static int lttng_ust_comm_should_quit; | |
60 | ||
11ff9c7d MD |
61 | /* |
62 | * Wait for either of these before continuing to the main | |
63 | * program: | |
64 | * - the register_done message from sessiond daemon | |
65 | * (will let the sessiond daemon enable sessions before main | |
66 | * starts.) | |
67 | * - sessiond daemon is not reachable. | |
68 | * - timeout (ensuring applications are resilient to session | |
69 | * daemon problems). | |
70 | */ | |
71 | static sem_t constructor_wait; | |
950aab0c MD |
72 | /* |
73 | * Doing this for both the global and local sessiond. | |
74 | */ | |
95259bd0 | 75 | static int sem_count = { 2 }; |
11ff9c7d | 76 | |
1ea11eab MD |
77 | /* |
78 | * Info about socket and associated listener thread. | |
79 | */ | |
80 | struct sock_info { | |
11ff9c7d | 81 | const char *name; |
1ea11eab | 82 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 83 | int root_handle; |
8d20bf54 MD |
84 | int constructor_sem_posted; |
85 | int allowed; | |
44e073f5 | 86 | int global; |
7fc90dca MD |
87 | |
88 | char sock_path[PATH_MAX]; | |
89 | int socket; | |
90 | ||
91 | char wait_shm_path[PATH_MAX]; | |
92 | char *wait_shm_mmap; | |
1ea11eab | 93 | }; |
2691221a MD |
94 | |
95 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 96 | struct sock_info global_apps = { |
11ff9c7d | 97 | .name = "global", |
44e073f5 | 98 | .global = 1, |
7fc90dca | 99 | |
46050b1a | 100 | .root_handle = -1, |
8d20bf54 | 101 | .allowed = 1, |
7fc90dca MD |
102 | |
103 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
104 | .socket = -1, | |
105 | ||
106 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 107 | }; |
2691221a MD |
108 | |
109 | /* TODO: allow global_apps_sock_path override */ | |
110 | ||
1ea11eab | 111 | struct sock_info local_apps = { |
11ff9c7d | 112 | .name = "local", |
44e073f5 | 113 | .global = 0, |
46050b1a | 114 | .root_handle = -1, |
8d20bf54 | 115 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
116 | |
117 | .socket = -1, | |
1ea11eab | 118 | }; |
2691221a | 119 | |
edaa1431 MD |
120 | extern void ltt_ring_buffer_client_overwrite_init(void); |
121 | extern void ltt_ring_buffer_client_discard_init(void); | |
122 | extern void ltt_ring_buffer_metadata_client_init(void); | |
123 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
124 | extern void ltt_ring_buffer_client_discard_exit(void); | |
125 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
126 | ||
2691221a | 127 | static |
8d20bf54 | 128 | int setup_local_apps(void) |
2691221a MD |
129 | { |
130 | const char *home_dir; | |
7fc90dca | 131 | uid_t uid; |
2691221a | 132 | |
7fc90dca | 133 | uid = getuid(); |
8d20bf54 MD |
134 | /* |
135 | * Disallow per-user tracing for setuid binaries. | |
136 | */ | |
7fc90dca | 137 | if (uid != geteuid()) { |
8d20bf54 | 138 | local_apps.allowed = 0; |
d0a1ae63 | 139 | return 0; |
8d20bf54 MD |
140 | } else { |
141 | local_apps.allowed = 1; | |
142 | } | |
2691221a MD |
143 | home_dir = (const char *) getenv("HOME"); |
144 | if (!home_dir) | |
145 | return -ENOENT; | |
1ea11eab | 146 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 147 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
148 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
149 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
150 | return 0; |
151 | } | |
152 | ||
153 | static | |
154 | int register_app_to_sessiond(int socket) | |
155 | { | |
156 | ssize_t ret; | |
2629549e | 157 | int prctl_ret; |
2691221a | 158 | struct { |
e44418f3 MD |
159 | uint32_t major; |
160 | uint32_t minor; | |
2691221a | 161 | pid_t pid; |
5c33bde8 | 162 | pid_t ppid; |
2691221a | 163 | uid_t uid; |
83610856 | 164 | gid_t gid; |
2629549e | 165 | char name[16]; /* process name */ |
2691221a MD |
166 | } reg_msg; |
167 | ||
e44418f3 MD |
168 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
169 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 170 | reg_msg.pid = getpid(); |
5c33bde8 | 171 | reg_msg.ppid = getppid(); |
2691221a | 172 | reg_msg.uid = getuid(); |
83610856 | 173 | reg_msg.gid = getgid(); |
2629549e MD |
174 | prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0); |
175 | if (prctl_ret) { | |
176 | ERR("Error executing prctl"); | |
177 | return -errno; | |
178 | } | |
2691221a MD |
179 | |
180 | ret = lttcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); | |
181 | if (ret >= 0 && ret != sizeof(reg_msg)) | |
182 | return -EIO; | |
183 | return ret; | |
184 | } | |
185 | ||
d9e99d10 | 186 | static |
d3a492d1 | 187 | int send_reply(int sock, struct lttcomm_ust_reply *lur) |
d9e99d10 | 188 | { |
9eb62b9c | 189 | ssize_t len; |
d3a492d1 | 190 | |
a4be8962 | 191 | len = lttcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 192 | switch (len) { |
a4be8962 | 193 | case sizeof(*lur): |
d3a492d1 MD |
194 | DBG("message successfully sent"); |
195 | return 0; | |
196 | case -1: | |
197 | if (errno == ECONNRESET) { | |
198 | printf("remote end closed connection\n"); | |
199 | return 0; | |
200 | } | |
201 | return -1; | |
202 | default: | |
203 | printf("incorrect message size: %zd\n", len); | |
204 | return -1; | |
205 | } | |
206 | } | |
207 | ||
208 | static | |
edaa1431 | 209 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
210 | { |
211 | int ret; | |
212 | ||
edaa1431 MD |
213 | if (sock_info->constructor_sem_posted) |
214 | return 0; | |
215 | sock_info->constructor_sem_posted = 1; | |
95259bd0 MD |
216 | ret = uatomic_add_return(&sem_count, -1); |
217 | if (ret == 0) { | |
218 | ret = sem_post(&constructor_wait); | |
219 | assert(!ret); | |
220 | } | |
11ff9c7d MD |
221 | return 0; |
222 | } | |
223 | ||
224 | static | |
225 | int handle_message(struct sock_info *sock_info, | |
226 | int sock, struct lttcomm_ust_msg *lum) | |
d3a492d1 | 227 | { |
1ea11eab | 228 | int ret = 0; |
46050b1a MD |
229 | const struct objd_ops *ops; |
230 | struct lttcomm_ust_reply lur; | |
1ea11eab | 231 | |
17dfb34b | 232 | ust_lock(); |
1ea11eab | 233 | |
46050b1a MD |
234 | memset(&lur, 0, sizeof(lur)); |
235 | ||
1ea11eab | 236 | if (lttng_ust_comm_should_quit) { |
46050b1a | 237 | ret = -EPERM; |
1ea11eab MD |
238 | goto end; |
239 | } | |
9eb62b9c | 240 | |
46050b1a MD |
241 | ops = objd_ops(lum->handle); |
242 | if (!ops) { | |
243 | ret = -ENOENT; | |
244 | goto end; | |
1ea11eab | 245 | } |
46050b1a MD |
246 | |
247 | switch (lum->cmd) { | |
11ff9c7d MD |
248 | case LTTNG_UST_REGISTER_DONE: |
249 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 250 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
251 | else |
252 | ret = -EINVAL; | |
253 | break; | |
46050b1a MD |
254 | case LTTNG_UST_RELEASE: |
255 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
256 | ret = -EPERM; | |
257 | else | |
258 | ret = objd_unref(lum->handle); | |
d9e99d10 MD |
259 | break; |
260 | default: | |
46050b1a MD |
261 | if (ops->cmd) |
262 | ret = ops->cmd(lum->handle, lum->cmd, | |
263 | (unsigned long) &lum->u); | |
264 | else | |
265 | ret = -ENOSYS; | |
266 | break; | |
d9e99d10 | 267 | } |
46050b1a | 268 | |
1ea11eab | 269 | end: |
46050b1a MD |
270 | lur.handle = lum->handle; |
271 | lur.cmd = lum->cmd; | |
272 | lur.ret_val = ret; | |
273 | if (ret >= 0) { | |
274 | lur.ret_code = LTTCOMM_OK; | |
275 | } else { | |
276 | lur.ret_code = LTTCOMM_SESSION_FAIL; | |
277 | } | |
278 | ret = send_reply(sock, &lur); | |
279 | ||
17dfb34b | 280 | ust_unlock(); |
1ea11eab | 281 | return ret; |
d9e99d10 MD |
282 | } |
283 | ||
46050b1a MD |
284 | static |
285 | void cleanup_sock_info(struct sock_info *sock_info) | |
286 | { | |
287 | int ret; | |
288 | ||
289 | if (sock_info->socket != -1) { | |
290 | ret = close(sock_info->socket); | |
291 | if (ret) { | |
7fc90dca | 292 | ERR("Error closing apps socket"); |
46050b1a MD |
293 | } |
294 | sock_info->socket = -1; | |
295 | } | |
296 | if (sock_info->root_handle != -1) { | |
297 | ret = objd_unref(sock_info->root_handle); | |
298 | if (ret) { | |
299 | ERR("Error unref root handle"); | |
300 | } | |
301 | sock_info->root_handle = -1; | |
302 | } | |
318dfea9 | 303 | sock_info->constructor_sem_posted = 0; |
7fc90dca MD |
304 | if (sock_info->wait_shm_mmap) { |
305 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); | |
306 | if (ret) { | |
307 | ERR("Error unmapping wait shm"); | |
308 | } | |
309 | sock_info->wait_shm_mmap = NULL; | |
310 | } | |
311 | } | |
312 | ||
58d4b2a2 MD |
313 | /* |
314 | * Using fork to set umask to 0777 in the child process (not | |
315 | * multi-thread safe). | |
316 | */ | |
7fc90dca | 317 | static |
58d4b2a2 | 318 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 319 | { |
7fc90dca | 320 | int wait_shm_fd, ret; |
58d4b2a2 MD |
321 | int read_mode; |
322 | pid_t pid; | |
44e073f5 | 323 | |
58d4b2a2 MD |
324 | /* |
325 | * At this point, we should be able to open it for | |
326 | * reading. If it fails, then it's because there is | |
327 | * something wrong: bail out in that case. | |
328 | */ | |
329 | read_mode = S_IRUSR | S_IRGRP; | |
44e073f5 | 330 | if (sock_info->global) |
58d4b2a2 | 331 | read_mode |= S_IROTH; |
7fc90dca MD |
332 | |
333 | /* | |
58d4b2a2 MD |
334 | * Try to open read-only. If it is set read-only, it |
335 | * means the shm size has been already set with | |
336 | * ftruncate. Note: all processes creating shm need to | |
337 | * call ftruncate on the shm before restricting its | |
338 | * access rights to read-only. The shm should never be | |
339 | * unlinked. It a rogue process try to create a non-accessible | |
340 | * shm or to unlink it, the worse-case scenario is that we don't | |
341 | * use the shm wakeup method and sleep/retry instead. | |
7fc90dca MD |
342 | */ |
343 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
58d4b2a2 MD |
344 | O_RDONLY, read_mode); |
345 | if (wait_shm_fd >= 0) { | |
346 | goto end; | |
347 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
348 | /* | |
349 | * Real-only open did not work. It's a failure | |
350 | * that prohibits using shm. | |
351 | */ | |
7fc90dca | 352 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 353 | goto end; |
7fc90dca | 354 | } |
58d4b2a2 | 355 | |
7fc90dca | 356 | /* |
58d4b2a2 MD |
357 | * If the open failed because the file did not exist, try |
358 | * creating it ourself. | |
7fc90dca | 359 | */ |
58d4b2a2 MD |
360 | pid = fork(); |
361 | if (pid > 0) { | |
362 | int status; | |
363 | ||
364 | /* | |
365 | * Parent: wait for child to return, in which case the | |
366 | * shared memory map will have been created. | |
367 | */ | |
368 | pid = wait(&status); | |
369 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { | |
370 | wait_shm_fd = -1; | |
371 | goto end; | |
7fc90dca | 372 | } |
58d4b2a2 MD |
373 | /* |
374 | * Try to open read-only again after creation. | |
375 | */ | |
376 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
377 | O_RDONLY, read_mode); | |
378 | if (wait_shm_fd < 0) { | |
379 | /* | |
380 | * Real-only open did not work. It's a failure | |
381 | * that prohibits using shm. | |
382 | */ | |
383 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
384 | goto end; | |
385 | } | |
386 | goto end; | |
387 | } else if (pid == 0) { | |
388 | int create_mode; | |
389 | ||
390 | /* Child */ | |
391 | create_mode = S_IRUSR | S_IRGRP | S_IWUSR | S_IWGRP; | |
392 | if (sock_info->global) | |
393 | create_mode |= S_IROTH | S_IWOTH; | |
394 | /* | |
395 | * We're alone in a child process, so we can modify the | |
396 | * process-wide umask. | |
397 | */ | |
398 | umask(create_mode); | |
399 | /* | |
400 | * First try creating shm (or get rw access). We need to start | |
401 | * by this because of the ftruncate vs concurrent map race. | |
402 | * We need to give write access to everyone because of the | |
403 | * ftruncate vs mmap race too. We don't do an exclusive | |
404 | * open, because we allow other processes to | |
405 | * create+ftruncate it concurrently. | |
406 | */ | |
407 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
408 | O_RDWR | O_CREAT, create_mode); | |
409 | if (wait_shm_fd >= 0) { | |
410 | ret = ftruncate(wait_shm_fd, mmap_size); | |
411 | if (ret) { | |
412 | PERROR("ftruncate"); | |
413 | exit(EXIT_FAILURE); | |
414 | } | |
415 | ret = fchmod(wait_shm_fd, read_mode); | |
416 | if (ret) { | |
417 | PERROR("fchmod"); | |
418 | exit(EXIT_FAILURE); | |
419 | } | |
420 | exit(EXIT_SUCCESS); | |
421 | } | |
422 | if (errno != EACCES) { | |
423 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
424 | exit(EXIT_FAILURE); | |
425 | } | |
426 | /* | |
427 | * The shm exists, but we cannot open it RW. It means it | |
428 | * has already been setup and ftruncated, so we can | |
429 | * let the child exit. | |
430 | */ | |
431 | exit(EXIT_SUCCESS); | |
432 | } else { | |
433 | return -1; | |
7fc90dca | 434 | } |
58d4b2a2 MD |
435 | end: |
436 | return wait_shm_fd; | |
437 | } | |
438 | ||
439 | static | |
440 | char *get_map_shm(struct sock_info *sock_info) | |
441 | { | |
442 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
443 | int wait_shm_fd, ret; | |
444 | char *wait_shm_mmap; | |
445 | ||
446 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
447 | if (wait_shm_fd < 0) { | |
448 | goto error; | |
44e073f5 | 449 | } |
7fc90dca MD |
450 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
451 | MAP_SHARED, wait_shm_fd, 0); | |
452 | if (wait_shm_mmap == MAP_FAILED) { | |
453 | PERROR("mmap"); | |
454 | goto error; | |
455 | } | |
456 | /* close shm fd immediately after taking the mmap reference */ | |
457 | ret = close(wait_shm_fd); | |
458 | if (ret) { | |
459 | ERR("Error closing fd"); | |
460 | } | |
461 | return wait_shm_mmap; | |
462 | ||
463 | error: | |
464 | return NULL; | |
465 | } | |
466 | ||
467 | static | |
468 | void wait_for_sessiond(struct sock_info *sock_info) | |
469 | { | |
470 | ust_lock(); | |
471 | if (lttng_ust_comm_should_quit) { | |
472 | goto quit; | |
473 | } | |
474 | if (!sock_info->wait_shm_mmap) { | |
475 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
476 | if (!sock_info->wait_shm_mmap) | |
477 | goto error; | |
478 | } | |
479 | ust_unlock(); | |
480 | ||
481 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
482 | /* Wait for futex wakeup TODO */ | |
483 | sleep(5); | |
484 | ||
485 | return; | |
486 | ||
487 | quit: | |
488 | ust_unlock(); | |
489 | return; | |
490 | ||
491 | error: | |
492 | ust_unlock(); | |
493 | /* Error handling: fallback on a 5 seconds sleep. */ | |
494 | sleep(5); | |
495 | return; | |
46050b1a MD |
496 | } |
497 | ||
1ea11eab MD |
498 | /* |
499 | * This thread does not allocate any resource, except within | |
500 | * handle_message, within mutex protection. This mutex protects against | |
501 | * fork and exit. | |
502 | * The other moment it allocates resources is at socket connexion, which | |
503 | * is also protected by the mutex. | |
504 | */ | |
d9e99d10 MD |
505 | static |
506 | void *ust_listener_thread(void *arg) | |
507 | { | |
1ea11eab MD |
508 | struct sock_info *sock_info = arg; |
509 | int sock, ret; | |
d9e99d10 | 510 | |
9eb62b9c MD |
511 | /* Restart trying to connect to the session daemon */ |
512 | restart: | |
17dfb34b | 513 | ust_lock(); |
1ea11eab MD |
514 | |
515 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 516 | ust_unlock(); |
1ea11eab MD |
517 | goto quit; |
518 | } | |
9eb62b9c | 519 | |
1ea11eab MD |
520 | if (sock_info->socket != -1) { |
521 | ret = close(sock_info->socket); | |
522 | if (ret) { | |
11ff9c7d | 523 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
524 | } |
525 | sock_info->socket = -1; | |
526 | } | |
46050b1a | 527 | |
9eb62b9c | 528 | /* Register */ |
1ea11eab | 529 | ret = lttcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 530 | if (ret < 0) { |
11ff9c7d MD |
531 | ERR("Error connecting to %s apps socket", sock_info->name); |
532 | /* | |
533 | * If we cannot find the sessiond daemon, don't delay | |
534 | * constructor execution. | |
535 | */ | |
edaa1431 | 536 | ret = handle_register_done(sock_info); |
11ff9c7d | 537 | assert(!ret); |
17dfb34b | 538 | ust_unlock(); |
7fc90dca MD |
539 | |
540 | /* Wait for sessiond availability with pipe */ | |
541 | wait_for_sessiond(sock_info); | |
1ea11eab | 542 | goto restart; |
46050b1a MD |
543 | } |
544 | ||
545 | sock_info->socket = sock = ret; | |
546 | ||
547 | /* | |
548 | * Create only one root handle per listener thread for the whole | |
549 | * process lifetime. | |
550 | */ | |
551 | if (sock_info->root_handle == -1) { | |
552 | ret = lttng_abi_create_root_handle(); | |
553 | if (ret) { | |
554 | ERR("Error creating root handle"); | |
17dfb34b | 555 | ust_unlock(); |
46050b1a MD |
556 | goto quit; |
557 | } | |
558 | sock_info->root_handle = ret; | |
9eb62b9c | 559 | } |
1ea11eab | 560 | |
9eb62b9c MD |
561 | ret = register_app_to_sessiond(sock); |
562 | if (ret < 0) { | |
11ff9c7d MD |
563 | ERR("Error registering to %s apps socket", sock_info->name); |
564 | /* | |
565 | * If we cannot register to the sessiond daemon, don't | |
566 | * delay constructor execution. | |
567 | */ | |
edaa1431 | 568 | ret = handle_register_done(sock_info); |
11ff9c7d | 569 | assert(!ret); |
17dfb34b | 570 | ust_unlock(); |
7fc90dca | 571 | wait_for_sessiond(sock_info); |
9eb62b9c MD |
572 | goto restart; |
573 | } | |
17dfb34b | 574 | ust_unlock(); |
46050b1a | 575 | |
d9e99d10 MD |
576 | for (;;) { |
577 | ssize_t len; | |
e7723462 | 578 | struct lttcomm_ust_msg lum; |
d9e99d10 | 579 | |
e7723462 | 580 | len = lttcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
581 | switch (len) { |
582 | case 0: /* orderly shutdown */ | |
11ff9c7d | 583 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
d9e99d10 | 584 | goto end; |
e7723462 | 585 | case sizeof(lum): |
d9e99d10 | 586 | DBG("message received\n"); |
11ff9c7d | 587 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 588 | if (ret < 0) { |
11ff9c7d | 589 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
590 | } |
591 | continue; | |
592 | case -1: | |
593 | if (errno == ECONNRESET) { | |
11ff9c7d | 594 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
595 | goto end; |
596 | } | |
597 | goto end; | |
598 | default: | |
11ff9c7d | 599 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
600 | continue; |
601 | } | |
602 | ||
603 | } | |
604 | end: | |
9eb62b9c | 605 | goto restart; /* try to reconnect */ |
1ea11eab | 606 | quit: |
d9e99d10 MD |
607 | return NULL; |
608 | } | |
609 | ||
cf12a773 MD |
610 | /* |
611 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
612 | */ | |
11ff9c7d MD |
613 | static |
614 | int get_timeout(struct timespec *constructor_timeout) | |
615 | { | |
cf12a773 MD |
616 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
617 | char *str_delay; | |
11ff9c7d MD |
618 | int ret; |
619 | ||
cf12a773 MD |
620 | str_delay = getenv("UST_REGISTER_TIMEOUT"); |
621 | if (str_delay) { | |
622 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
623 | } | |
624 | ||
625 | switch (constructor_delay_ms) { | |
626 | case -1:/* fall-through */ | |
627 | case 0: | |
628 | return constructor_delay_ms; | |
629 | default: | |
630 | break; | |
631 | } | |
632 | ||
633 | /* | |
634 | * If we are unable to find the current time, don't wait. | |
635 | */ | |
636 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
637 | if (ret) { | |
638 | return -1; | |
639 | } | |
95259bd0 MD |
640 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
641 | constructor_timeout->tv_nsec += | |
642 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
643 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
644 | constructor_timeout->tv_sec++; | |
645 | constructor_timeout->tv_nsec -= 1000000000UL; | |
646 | } | |
cf12a773 | 647 | return 1; |
11ff9c7d | 648 | } |
d9e99d10 | 649 | |
2691221a MD |
650 | /* |
651 | * sessiond monitoring thread: monitor presence of global and per-user | |
652 | * sessiond by polling the application common named pipe. | |
653 | */ | |
654 | /* TODO */ | |
655 | ||
edaa1431 | 656 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 657 | { |
11ff9c7d | 658 | struct timespec constructor_timeout; |
cf12a773 | 659 | int timeout_mode; |
2691221a MD |
660 | int ret; |
661 | ||
edaa1431 MD |
662 | if (uatomic_xchg(&initialized, 1) == 1) |
663 | return; | |
664 | ||
665 | /* | |
666 | * We want precise control over the order in which we construct | |
667 | * our sub-libraries vs starting to receive commands from | |
668 | * sessiond (otherwise leading to errors when trying to create | |
669 | * sessiond before the init functions are completed). | |
670 | */ | |
2691221a | 671 | init_usterr(); |
edaa1431 MD |
672 | init_tracepoint(); |
673 | ltt_ring_buffer_metadata_client_init(); | |
674 | ltt_ring_buffer_client_overwrite_init(); | |
675 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 676 | |
cf12a773 | 677 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 678 | |
95259bd0 | 679 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
680 | assert(!ret); |
681 | ||
8d20bf54 | 682 | ret = setup_local_apps(); |
2691221a | 683 | if (ret) { |
8d20bf54 | 684 | ERR("Error setting up to local apps"); |
2691221a | 685 | } |
1ea11eab MD |
686 | ret = pthread_create(&local_apps.ust_listener, NULL, |
687 | ust_listener_thread, &local_apps); | |
11ff9c7d | 688 | |
8d20bf54 MD |
689 | if (local_apps.allowed) { |
690 | ret = pthread_create(&global_apps.ust_listener, NULL, | |
691 | ust_listener_thread, &global_apps); | |
692 | } else { | |
693 | handle_register_done(&local_apps); | |
694 | } | |
695 | ||
cf12a773 MD |
696 | switch (timeout_mode) { |
697 | case 1: /* timeout wait */ | |
95259bd0 MD |
698 | do { |
699 | ret = sem_timedwait(&constructor_wait, | |
700 | &constructor_timeout); | |
701 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
702 | if (ret < 0 && errno == ETIMEDOUT) { |
703 | ERR("Timed out waiting for ltt-sessiond"); | |
704 | } else { | |
705 | assert(!ret); | |
706 | } | |
707 | break; | |
7b766b16 | 708 | case -1:/* wait forever */ |
95259bd0 MD |
709 | do { |
710 | ret = sem_wait(&constructor_wait); | |
711 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 712 | assert(!ret); |
cf12a773 | 713 | break; |
7b766b16 | 714 | case 0: /* no timeout */ |
cf12a773 | 715 | break; |
11ff9c7d | 716 | } |
2691221a MD |
717 | } |
718 | ||
17dfb34b MD |
719 | static |
720 | void lttng_ust_cleanup(int exiting) | |
721 | { | |
722 | cleanup_sock_info(&global_apps); | |
723 | if (local_apps.allowed) { | |
724 | cleanup_sock_info(&local_apps); | |
725 | } | |
726 | lttng_ust_abi_exit(); | |
727 | ltt_events_exit(); | |
728 | ltt_ring_buffer_client_discard_exit(); | |
729 | ltt_ring_buffer_client_overwrite_exit(); | |
730 | ltt_ring_buffer_metadata_client_exit(); | |
731 | exit_tracepoint(); | |
732 | if (!exiting) { | |
733 | /* Reinitialize values for fork */ | |
734 | sem_count = 2; | |
735 | lttng_ust_comm_should_quit = 0; | |
736 | initialized = 0; | |
737 | } | |
738 | } | |
739 | ||
edaa1431 | 740 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
741 | { |
742 | int ret; | |
743 | ||
9eb62b9c MD |
744 | /* |
745 | * Using pthread_cancel here because: | |
746 | * A) we don't want to hang application teardown. | |
747 | * B) the thread is not allocating any resource. | |
748 | */ | |
1ea11eab MD |
749 | |
750 | /* | |
751 | * Require the communication thread to quit. Synchronize with | |
752 | * mutexes to ensure it is not in a mutex critical section when | |
753 | * pthread_cancel is later called. | |
754 | */ | |
17dfb34b | 755 | ust_lock(); |
1ea11eab | 756 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 757 | ust_unlock(); |
1ea11eab | 758 | |
1ea11eab | 759 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c MD |
760 | if (ret) { |
761 | ERR("Error cancelling global ust listener thread"); | |
2691221a | 762 | } |
8d20bf54 MD |
763 | if (local_apps.allowed) { |
764 | ret = pthread_cancel(local_apps.ust_listener); | |
765 | if (ret) { | |
766 | ERR("Error cancelling local ust listener thread"); | |
767 | } | |
8d20bf54 | 768 | } |
17dfb34b | 769 | lttng_ust_cleanup(1); |
2691221a | 770 | } |
e822f505 MD |
771 | |
772 | /* | |
773 | * We exclude the worker threads across fork and clone (except | |
774 | * CLONE_VM), because these system calls only keep the forking thread | |
775 | * running in the child. Therefore, we don't want to call fork or clone | |
776 | * in the middle of an tracepoint or ust tracing state modification. | |
777 | * Holding this mutex protects these structures across fork and clone. | |
778 | */ | |
779 | void ust_before_fork(ust_fork_info_t *fork_info) | |
780 | { | |
781 | /* | |
782 | * Disable signals. This is to avoid that the child intervenes | |
783 | * before it is properly setup for tracing. It is safer to | |
784 | * disable all signals, because then we know we are not breaking | |
785 | * anything by restoring the original mask. | |
786 | */ | |
787 | sigset_t all_sigs; | |
788 | int ret; | |
789 | ||
790 | /* Disable signals */ | |
791 | sigfillset(&all_sigs); | |
792 | ret = sigprocmask(SIG_BLOCK, &all_sigs, &fork_info->orig_sigs); | |
793 | if (ret == -1) { | |
794 | PERROR("sigprocmask"); | |
795 | } | |
17dfb34b | 796 | ust_lock(); |
e822f505 MD |
797 | rcu_bp_before_fork(); |
798 | } | |
799 | ||
800 | static void ust_after_fork_common(ust_fork_info_t *fork_info) | |
801 | { | |
802 | int ret; | |
803 | ||
17dfb34b MD |
804 | DBG("process %d", getpid()); |
805 | ust_unlock(); | |
e822f505 MD |
806 | /* Restore signals */ |
807 | ret = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL); | |
808 | if (ret == -1) { | |
809 | PERROR("sigprocmask"); | |
810 | } | |
811 | } | |
812 | ||
813 | void ust_after_fork_parent(ust_fork_info_t *fork_info) | |
814 | { | |
17dfb34b | 815 | DBG("process %d", getpid()); |
e822f505 MD |
816 | rcu_bp_after_fork_parent(); |
817 | /* Release mutexes and reenable signals */ | |
818 | ust_after_fork_common(fork_info); | |
819 | } | |
820 | ||
17dfb34b MD |
821 | /* |
822 | * After fork, in the child, we need to cleanup all the leftover state, | |
823 | * except the worker thread which already magically disappeared thanks | |
824 | * to the weird Linux fork semantics. After tyding up, we call | |
825 | * lttng_ust_init() again to start over as a new PID. | |
826 | * | |
827 | * This is meant for forks() that have tracing in the child between the | |
828 | * fork and following exec call (if there is any). | |
829 | */ | |
e822f505 MD |
830 | void ust_after_fork_child(ust_fork_info_t *fork_info) |
831 | { | |
17dfb34b | 832 | DBG("process %d", getpid()); |
e822f505 MD |
833 | /* Release urcu mutexes */ |
834 | rcu_bp_after_fork_child(); | |
17dfb34b | 835 | lttng_ust_cleanup(0); |
e822f505 MD |
836 | /* Release mutexes and reenable signals */ |
837 | ust_after_fork_common(fork_info); | |
318dfea9 | 838 | lttng_ust_init(); |
e822f505 | 839 | } |