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> | |
2629549e | 25 | #include <sys/prctl.h> |
7fc90dca MD |
26 | #include <sys/mman.h> |
27 | #include <sys/stat.h> | |
58d4b2a2 MD |
28 | #include <sys/types.h> |
29 | #include <sys/wait.h> | |
7fc90dca | 30 | #include <fcntl.h> |
2691221a MD |
31 | #include <unistd.h> |
32 | #include <errno.h> | |
d9e99d10 | 33 | #include <pthread.h> |
11ff9c7d MD |
34 | #include <semaphore.h> |
35 | #include <time.h> | |
1ea11eab | 36 | #include <assert.h> |
e822f505 | 37 | #include <signal.h> |
95259bd0 | 38 | #include <urcu/uatomic.h> |
80e2814b | 39 | #include <urcu/futex.h> |
1ea11eab | 40 | |
edaa1431 MD |
41 | #include <lttng-ust-comm.h> |
42 | #include <ust/usterr-signal-safe.h> | |
43 | #include <ust/lttng-ust-abi.h> | |
44 | #include <ust/tracepoint.h> | |
d0a1ae63 | 45 | #include <ust/tracepoint-internal.h> |
e822f505 | 46 | #include <ust/ust.h> |
b751f722 | 47 | #include "ltt-tracer-core.h" |
edaa1431 MD |
48 | |
49 | /* | |
50 | * Has lttng ust comm constructor been called ? | |
51 | */ | |
52 | static int initialized; | |
53 | ||
1ea11eab | 54 | /* |
17dfb34b MD |
55 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
56 | * Held when handling a command, also held by fork() to deal with | |
57 | * removal of threads, and by exit path. | |
1ea11eab | 58 | */ |
1ea11eab MD |
59 | |
60 | /* Should the ust comm thread quit ? */ | |
61 | static int lttng_ust_comm_should_quit; | |
62 | ||
11ff9c7d MD |
63 | /* |
64 | * Wait for either of these before continuing to the main | |
65 | * program: | |
66 | * - the register_done message from sessiond daemon | |
67 | * (will let the sessiond daemon enable sessions before main | |
68 | * starts.) | |
69 | * - sessiond daemon is not reachable. | |
70 | * - timeout (ensuring applications are resilient to session | |
71 | * daemon problems). | |
72 | */ | |
73 | static sem_t constructor_wait; | |
950aab0c MD |
74 | /* |
75 | * Doing this for both the global and local sessiond. | |
76 | */ | |
95259bd0 | 77 | static int sem_count = { 2 }; |
11ff9c7d | 78 | |
1ea11eab MD |
79 | /* |
80 | * Info about socket and associated listener thread. | |
81 | */ | |
82 | struct sock_info { | |
11ff9c7d | 83 | const char *name; |
1ea11eab | 84 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 85 | int root_handle; |
8d20bf54 MD |
86 | int constructor_sem_posted; |
87 | int allowed; | |
44e073f5 | 88 | int global; |
7fc90dca MD |
89 | |
90 | char sock_path[PATH_MAX]; | |
91 | int socket; | |
92 | ||
93 | char wait_shm_path[PATH_MAX]; | |
94 | char *wait_shm_mmap; | |
1ea11eab | 95 | }; |
2691221a MD |
96 | |
97 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 98 | struct sock_info global_apps = { |
11ff9c7d | 99 | .name = "global", |
44e073f5 | 100 | .global = 1, |
7fc90dca | 101 | |
46050b1a | 102 | .root_handle = -1, |
8d20bf54 | 103 | .allowed = 1, |
7fc90dca MD |
104 | |
105 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
106 | .socket = -1, | |
107 | ||
108 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 109 | }; |
2691221a MD |
110 | |
111 | /* TODO: allow global_apps_sock_path override */ | |
112 | ||
1ea11eab | 113 | struct sock_info local_apps = { |
11ff9c7d | 114 | .name = "local", |
44e073f5 | 115 | .global = 0, |
46050b1a | 116 | .root_handle = -1, |
8d20bf54 | 117 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
118 | |
119 | .socket = -1, | |
1ea11eab | 120 | }; |
2691221a | 121 | |
edaa1431 MD |
122 | extern void ltt_ring_buffer_client_overwrite_init(void); |
123 | extern void ltt_ring_buffer_client_discard_init(void); | |
124 | extern void ltt_ring_buffer_metadata_client_init(void); | |
125 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
126 | extern void ltt_ring_buffer_client_discard_exit(void); | |
127 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
128 | ||
2691221a | 129 | static |
8d20bf54 | 130 | int setup_local_apps(void) |
2691221a MD |
131 | { |
132 | const char *home_dir; | |
7fc90dca | 133 | uid_t uid; |
2691221a | 134 | |
7fc90dca | 135 | uid = getuid(); |
8d20bf54 MD |
136 | /* |
137 | * Disallow per-user tracing for setuid binaries. | |
138 | */ | |
7fc90dca | 139 | if (uid != geteuid()) { |
8d20bf54 | 140 | local_apps.allowed = 0; |
d0a1ae63 | 141 | return 0; |
8d20bf54 MD |
142 | } else { |
143 | local_apps.allowed = 1; | |
144 | } | |
2691221a MD |
145 | home_dir = (const char *) getenv("HOME"); |
146 | if (!home_dir) | |
147 | return -ENOENT; | |
1ea11eab | 148 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 149 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
150 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
151 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
152 | return 0; |
153 | } | |
154 | ||
155 | static | |
156 | int register_app_to_sessiond(int socket) | |
157 | { | |
158 | ssize_t ret; | |
2629549e | 159 | int prctl_ret; |
2691221a | 160 | struct { |
e44418f3 MD |
161 | uint32_t major; |
162 | uint32_t minor; | |
2691221a | 163 | pid_t pid; |
5c33bde8 | 164 | pid_t ppid; |
2691221a | 165 | uid_t uid; |
83610856 | 166 | gid_t gid; |
2629549e | 167 | char name[16]; /* process name */ |
2691221a MD |
168 | } reg_msg; |
169 | ||
e44418f3 MD |
170 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
171 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 172 | reg_msg.pid = getpid(); |
5c33bde8 | 173 | reg_msg.ppid = getppid(); |
2691221a | 174 | reg_msg.uid = getuid(); |
83610856 | 175 | reg_msg.gid = getgid(); |
2629549e MD |
176 | prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0); |
177 | if (prctl_ret) { | |
178 | ERR("Error executing prctl"); | |
179 | return -errno; | |
180 | } | |
2691221a MD |
181 | |
182 | ret = lttcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); | |
183 | if (ret >= 0 && ret != sizeof(reg_msg)) | |
184 | return -EIO; | |
185 | return ret; | |
186 | } | |
187 | ||
d9e99d10 | 188 | static |
d3a492d1 | 189 | int send_reply(int sock, struct lttcomm_ust_reply *lur) |
d9e99d10 | 190 | { |
9eb62b9c | 191 | ssize_t len; |
d3a492d1 | 192 | |
a4be8962 | 193 | len = lttcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 194 | switch (len) { |
a4be8962 | 195 | case sizeof(*lur): |
d3a492d1 MD |
196 | DBG("message successfully sent"); |
197 | return 0; | |
198 | case -1: | |
199 | if (errno == ECONNRESET) { | |
200 | printf("remote end closed connection\n"); | |
201 | return 0; | |
202 | } | |
203 | return -1; | |
204 | default: | |
205 | printf("incorrect message size: %zd\n", len); | |
206 | return -1; | |
207 | } | |
208 | } | |
209 | ||
210 | static | |
edaa1431 | 211 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
212 | { |
213 | int ret; | |
214 | ||
edaa1431 MD |
215 | if (sock_info->constructor_sem_posted) |
216 | return 0; | |
217 | sock_info->constructor_sem_posted = 1; | |
95259bd0 MD |
218 | ret = uatomic_add_return(&sem_count, -1); |
219 | if (ret == 0) { | |
220 | ret = sem_post(&constructor_wait); | |
221 | assert(!ret); | |
222 | } | |
11ff9c7d MD |
223 | return 0; |
224 | } | |
225 | ||
226 | static | |
227 | int handle_message(struct sock_info *sock_info, | |
228 | int sock, struct lttcomm_ust_msg *lum) | |
d3a492d1 | 229 | { |
1ea11eab | 230 | int ret = 0; |
46050b1a MD |
231 | const struct objd_ops *ops; |
232 | struct lttcomm_ust_reply lur; | |
1ea11eab | 233 | |
17dfb34b | 234 | ust_lock(); |
1ea11eab | 235 | |
46050b1a MD |
236 | memset(&lur, 0, sizeof(lur)); |
237 | ||
1ea11eab | 238 | if (lttng_ust_comm_should_quit) { |
46050b1a | 239 | ret = -EPERM; |
1ea11eab MD |
240 | goto end; |
241 | } | |
9eb62b9c | 242 | |
46050b1a MD |
243 | ops = objd_ops(lum->handle); |
244 | if (!ops) { | |
245 | ret = -ENOENT; | |
246 | goto end; | |
1ea11eab | 247 | } |
46050b1a MD |
248 | |
249 | switch (lum->cmd) { | |
11ff9c7d MD |
250 | case LTTNG_UST_REGISTER_DONE: |
251 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 252 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
253 | else |
254 | ret = -EINVAL; | |
255 | break; | |
46050b1a MD |
256 | case LTTNG_UST_RELEASE: |
257 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
258 | ret = -EPERM; | |
259 | else | |
260 | ret = objd_unref(lum->handle); | |
d9e99d10 MD |
261 | break; |
262 | default: | |
46050b1a MD |
263 | if (ops->cmd) |
264 | ret = ops->cmd(lum->handle, lum->cmd, | |
265 | (unsigned long) &lum->u); | |
266 | else | |
267 | ret = -ENOSYS; | |
268 | break; | |
d9e99d10 | 269 | } |
46050b1a | 270 | |
1ea11eab | 271 | end: |
46050b1a MD |
272 | lur.handle = lum->handle; |
273 | lur.cmd = lum->cmd; | |
274 | lur.ret_val = ret; | |
275 | if (ret >= 0) { | |
276 | lur.ret_code = LTTCOMM_OK; | |
277 | } else { | |
278 | lur.ret_code = LTTCOMM_SESSION_FAIL; | |
279 | } | |
280 | ret = send_reply(sock, &lur); | |
281 | ||
17dfb34b | 282 | ust_unlock(); |
1ea11eab | 283 | return ret; |
d9e99d10 MD |
284 | } |
285 | ||
46050b1a MD |
286 | static |
287 | void cleanup_sock_info(struct sock_info *sock_info) | |
288 | { | |
289 | int ret; | |
290 | ||
291 | if (sock_info->socket != -1) { | |
292 | ret = close(sock_info->socket); | |
293 | if (ret) { | |
7fc90dca | 294 | ERR("Error closing apps socket"); |
46050b1a MD |
295 | } |
296 | sock_info->socket = -1; | |
297 | } | |
298 | if (sock_info->root_handle != -1) { | |
299 | ret = objd_unref(sock_info->root_handle); | |
300 | if (ret) { | |
301 | ERR("Error unref root handle"); | |
302 | } | |
303 | sock_info->root_handle = -1; | |
304 | } | |
318dfea9 | 305 | sock_info->constructor_sem_posted = 0; |
7fc90dca MD |
306 | if (sock_info->wait_shm_mmap) { |
307 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); | |
308 | if (ret) { | |
309 | ERR("Error unmapping wait shm"); | |
310 | } | |
311 | sock_info->wait_shm_mmap = NULL; | |
312 | } | |
313 | } | |
314 | ||
58d4b2a2 | 315 | /* |
33bbeb90 MD |
316 | * Using fork to set umask in the child process (not multi-thread safe). |
317 | * We deal with the shm_open vs ftruncate race (happening when the | |
318 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
319 | * safety against shm_unlink) by simply letting the mmap fail and | |
320 | * retrying after a few seconds. | |
321 | * For global shm, everybody has rw access to it until the sessiond | |
322 | * starts. | |
58d4b2a2 | 323 | */ |
7fc90dca | 324 | static |
58d4b2a2 | 325 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 326 | { |
7fc90dca | 327 | int wait_shm_fd, ret; |
58d4b2a2 | 328 | pid_t pid; |
44e073f5 | 329 | |
58d4b2a2 | 330 | /* |
33bbeb90 | 331 | * Try to open read-only. |
58d4b2a2 | 332 | */ |
33bbeb90 | 333 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
334 | if (wait_shm_fd >= 0) { |
335 | goto end; | |
336 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
337 | /* | |
33bbeb90 MD |
338 | * Real-only open did not work, and it's not because the |
339 | * entry was not present. It's a failure that prohibits | |
340 | * using shm. | |
58d4b2a2 | 341 | */ |
7fc90dca | 342 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 343 | goto end; |
7fc90dca MD |
344 | } |
345 | /* | |
58d4b2a2 MD |
346 | * If the open failed because the file did not exist, try |
347 | * creating it ourself. | |
7fc90dca | 348 | */ |
58d4b2a2 MD |
349 | pid = fork(); |
350 | if (pid > 0) { | |
351 | int status; | |
352 | ||
353 | /* | |
354 | * Parent: wait for child to return, in which case the | |
355 | * shared memory map will have been created. | |
356 | */ | |
357 | pid = wait(&status); | |
358 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { | |
359 | wait_shm_fd = -1; | |
360 | goto end; | |
7fc90dca | 361 | } |
58d4b2a2 MD |
362 | /* |
363 | * Try to open read-only again after creation. | |
364 | */ | |
33bbeb90 | 365 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
366 | if (wait_shm_fd < 0) { |
367 | /* | |
368 | * Real-only open did not work. It's a failure | |
369 | * that prohibits using shm. | |
370 | */ | |
371 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
372 | goto end; | |
373 | } | |
374 | goto end; | |
375 | } else if (pid == 0) { | |
376 | int create_mode; | |
377 | ||
378 | /* Child */ | |
33bbeb90 | 379 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 380 | if (sock_info->global) |
33bbeb90 | 381 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
382 | /* |
383 | * We're alone in a child process, so we can modify the | |
384 | * process-wide umask. | |
385 | */ | |
33bbeb90 | 386 | umask(~create_mode); |
58d4b2a2 | 387 | /* |
33bbeb90 MD |
388 | * Try creating shm (or get rw access). |
389 | * We don't do an exclusive open, because we allow other | |
390 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
391 | */ |
392 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
393 | O_RDWR | O_CREAT, create_mode); | |
394 | if (wait_shm_fd >= 0) { | |
395 | ret = ftruncate(wait_shm_fd, mmap_size); | |
396 | if (ret) { | |
397 | PERROR("ftruncate"); | |
398 | exit(EXIT_FAILURE); | |
399 | } | |
58d4b2a2 MD |
400 | exit(EXIT_SUCCESS); |
401 | } | |
33bbeb90 MD |
402 | /* |
403 | * For local shm, we need to have rw access to accept | |
404 | * opening it: this means the local sessiond will be | |
405 | * able to wake us up. For global shm, we open it even | |
406 | * if rw access is not granted, because the root.root | |
407 | * sessiond will be able to override all rights and wake | |
408 | * us up. | |
409 | */ | |
410 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
411 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
412 | exit(EXIT_FAILURE); | |
413 | } | |
414 | /* | |
33bbeb90 MD |
415 | * The shm exists, but we cannot open it RW. Report |
416 | * success. | |
58d4b2a2 MD |
417 | */ |
418 | exit(EXIT_SUCCESS); | |
419 | } else { | |
420 | return -1; | |
7fc90dca | 421 | } |
58d4b2a2 | 422 | end: |
33bbeb90 MD |
423 | if (wait_shm_fd >= 0 && !sock_info->global) { |
424 | struct stat statbuf; | |
425 | ||
426 | /* | |
427 | * Ensure that our user is the owner of the shm file for | |
428 | * local shm. If we do not own the file, it means our | |
429 | * sessiond will not have access to wake us up (there is | |
430 | * probably a rogue process trying to fake our | |
431 | * sessiond). Fallback to polling method in this case. | |
432 | */ | |
433 | ret = fstat(wait_shm_fd, &statbuf); | |
434 | if (ret) { | |
435 | PERROR("fstat"); | |
436 | goto error_close; | |
437 | } | |
438 | if (statbuf.st_uid != getuid()) | |
439 | goto error_close; | |
440 | } | |
58d4b2a2 | 441 | return wait_shm_fd; |
33bbeb90 MD |
442 | |
443 | error_close: | |
444 | ret = close(wait_shm_fd); | |
445 | if (ret) { | |
446 | PERROR("Error closing fd"); | |
447 | } | |
448 | return -1; | |
58d4b2a2 MD |
449 | } |
450 | ||
451 | static | |
452 | char *get_map_shm(struct sock_info *sock_info) | |
453 | { | |
454 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
455 | int wait_shm_fd, ret; | |
456 | char *wait_shm_mmap; | |
457 | ||
458 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
459 | if (wait_shm_fd < 0) { | |
460 | goto error; | |
44e073f5 | 461 | } |
7fc90dca MD |
462 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
463 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
464 | /* close shm fd immediately after taking the mmap reference */ |
465 | ret = close(wait_shm_fd); | |
466 | if (ret) { | |
33bbeb90 MD |
467 | PERROR("Error closing fd"); |
468 | } | |
469 | if (wait_shm_mmap == MAP_FAILED) { | |
470 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
471 | goto error; | |
7fc90dca MD |
472 | } |
473 | return wait_shm_mmap; | |
474 | ||
475 | error: | |
476 | return NULL; | |
477 | } | |
478 | ||
479 | static | |
480 | void wait_for_sessiond(struct sock_info *sock_info) | |
481 | { | |
80e2814b MD |
482 | int ret; |
483 | ||
7fc90dca MD |
484 | ust_lock(); |
485 | if (lttng_ust_comm_should_quit) { | |
486 | goto quit; | |
487 | } | |
488 | if (!sock_info->wait_shm_mmap) { | |
489 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
490 | if (!sock_info->wait_shm_mmap) | |
491 | goto error; | |
492 | } | |
493 | ust_unlock(); | |
494 | ||
495 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
496 | /* Wait for futex wakeup */ |
497 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
498 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
499 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
500 | /* | |
501 | * FIXME: Currently, futexes on read-only shm seems to | |
502 | * EFAULT. | |
503 | */ | |
504 | if (ret < 0) { | |
505 | PERROR("futex"); | |
506 | sleep(5); | |
507 | } | |
508 | } | |
7fc90dca MD |
509 | return; |
510 | ||
511 | quit: | |
512 | ust_unlock(); | |
513 | return; | |
514 | ||
515 | error: | |
516 | ust_unlock(); | |
517 | /* Error handling: fallback on a 5 seconds sleep. */ | |
518 | sleep(5); | |
519 | return; | |
46050b1a MD |
520 | } |
521 | ||
1ea11eab MD |
522 | /* |
523 | * This thread does not allocate any resource, except within | |
524 | * handle_message, within mutex protection. This mutex protects against | |
525 | * fork and exit. | |
526 | * The other moment it allocates resources is at socket connexion, which | |
527 | * is also protected by the mutex. | |
528 | */ | |
d9e99d10 MD |
529 | static |
530 | void *ust_listener_thread(void *arg) | |
531 | { | |
1ea11eab MD |
532 | struct sock_info *sock_info = arg; |
533 | int sock, ret; | |
d9e99d10 | 534 | |
9eb62b9c MD |
535 | /* Restart trying to connect to the session daemon */ |
536 | restart: | |
17dfb34b | 537 | ust_lock(); |
1ea11eab MD |
538 | |
539 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 540 | ust_unlock(); |
1ea11eab MD |
541 | goto quit; |
542 | } | |
9eb62b9c | 543 | |
1ea11eab MD |
544 | if (sock_info->socket != -1) { |
545 | ret = close(sock_info->socket); | |
546 | if (ret) { | |
11ff9c7d | 547 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
548 | } |
549 | sock_info->socket = -1; | |
550 | } | |
46050b1a | 551 | |
9eb62b9c | 552 | /* Register */ |
1ea11eab | 553 | ret = lttcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 554 | if (ret < 0) { |
11ff9c7d MD |
555 | ERR("Error connecting to %s apps socket", sock_info->name); |
556 | /* | |
557 | * If we cannot find the sessiond daemon, don't delay | |
558 | * constructor execution. | |
559 | */ | |
edaa1431 | 560 | ret = handle_register_done(sock_info); |
11ff9c7d | 561 | assert(!ret); |
17dfb34b | 562 | ust_unlock(); |
7fc90dca MD |
563 | |
564 | /* Wait for sessiond availability with pipe */ | |
565 | wait_for_sessiond(sock_info); | |
1ea11eab | 566 | goto restart; |
46050b1a MD |
567 | } |
568 | ||
569 | sock_info->socket = sock = ret; | |
570 | ||
571 | /* | |
572 | * Create only one root handle per listener thread for the whole | |
573 | * process lifetime. | |
574 | */ | |
575 | if (sock_info->root_handle == -1) { | |
576 | ret = lttng_abi_create_root_handle(); | |
577 | if (ret) { | |
578 | ERR("Error creating root handle"); | |
17dfb34b | 579 | ust_unlock(); |
46050b1a MD |
580 | goto quit; |
581 | } | |
582 | sock_info->root_handle = ret; | |
9eb62b9c | 583 | } |
1ea11eab | 584 | |
9eb62b9c MD |
585 | ret = register_app_to_sessiond(sock); |
586 | if (ret < 0) { | |
11ff9c7d MD |
587 | ERR("Error registering to %s apps socket", sock_info->name); |
588 | /* | |
589 | * If we cannot register to the sessiond daemon, don't | |
590 | * delay constructor execution. | |
591 | */ | |
edaa1431 | 592 | ret = handle_register_done(sock_info); |
11ff9c7d | 593 | assert(!ret); |
17dfb34b | 594 | ust_unlock(); |
7fc90dca | 595 | wait_for_sessiond(sock_info); |
9eb62b9c MD |
596 | goto restart; |
597 | } | |
17dfb34b | 598 | ust_unlock(); |
46050b1a | 599 | |
d9e99d10 MD |
600 | for (;;) { |
601 | ssize_t len; | |
e7723462 | 602 | struct lttcomm_ust_msg lum; |
d9e99d10 | 603 | |
e7723462 | 604 | len = lttcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
605 | switch (len) { |
606 | case 0: /* orderly shutdown */ | |
11ff9c7d | 607 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
d9e99d10 | 608 | goto end; |
e7723462 | 609 | case sizeof(lum): |
d9e99d10 | 610 | DBG("message received\n"); |
11ff9c7d | 611 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 612 | if (ret < 0) { |
11ff9c7d | 613 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
614 | } |
615 | continue; | |
616 | case -1: | |
617 | if (errno == ECONNRESET) { | |
11ff9c7d | 618 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
619 | goto end; |
620 | } | |
621 | goto end; | |
622 | default: | |
11ff9c7d | 623 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
624 | continue; |
625 | } | |
626 | ||
627 | } | |
628 | end: | |
9eb62b9c | 629 | goto restart; /* try to reconnect */ |
1ea11eab | 630 | quit: |
d9e99d10 MD |
631 | return NULL; |
632 | } | |
633 | ||
cf12a773 MD |
634 | /* |
635 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
636 | */ | |
11ff9c7d MD |
637 | static |
638 | int get_timeout(struct timespec *constructor_timeout) | |
639 | { | |
cf12a773 MD |
640 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
641 | char *str_delay; | |
11ff9c7d MD |
642 | int ret; |
643 | ||
cf12a773 MD |
644 | str_delay = getenv("UST_REGISTER_TIMEOUT"); |
645 | if (str_delay) { | |
646 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
647 | } | |
648 | ||
649 | switch (constructor_delay_ms) { | |
650 | case -1:/* fall-through */ | |
651 | case 0: | |
652 | return constructor_delay_ms; | |
653 | default: | |
654 | break; | |
655 | } | |
656 | ||
657 | /* | |
658 | * If we are unable to find the current time, don't wait. | |
659 | */ | |
660 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
661 | if (ret) { | |
662 | return -1; | |
663 | } | |
95259bd0 MD |
664 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
665 | constructor_timeout->tv_nsec += | |
666 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
667 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
668 | constructor_timeout->tv_sec++; | |
669 | constructor_timeout->tv_nsec -= 1000000000UL; | |
670 | } | |
cf12a773 | 671 | return 1; |
11ff9c7d | 672 | } |
d9e99d10 | 673 | |
2691221a MD |
674 | /* |
675 | * sessiond monitoring thread: monitor presence of global and per-user | |
676 | * sessiond by polling the application common named pipe. | |
677 | */ | |
678 | /* TODO */ | |
679 | ||
edaa1431 | 680 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 681 | { |
11ff9c7d | 682 | struct timespec constructor_timeout; |
cf12a773 | 683 | int timeout_mode; |
2691221a MD |
684 | int ret; |
685 | ||
edaa1431 MD |
686 | if (uatomic_xchg(&initialized, 1) == 1) |
687 | return; | |
688 | ||
689 | /* | |
690 | * We want precise control over the order in which we construct | |
691 | * our sub-libraries vs starting to receive commands from | |
692 | * sessiond (otherwise leading to errors when trying to create | |
693 | * sessiond before the init functions are completed). | |
694 | */ | |
2691221a | 695 | init_usterr(); |
edaa1431 MD |
696 | init_tracepoint(); |
697 | ltt_ring_buffer_metadata_client_init(); | |
698 | ltt_ring_buffer_client_overwrite_init(); | |
699 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 700 | |
cf12a773 | 701 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 702 | |
95259bd0 | 703 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
704 | assert(!ret); |
705 | ||
8d20bf54 | 706 | ret = setup_local_apps(); |
2691221a | 707 | if (ret) { |
8d20bf54 | 708 | ERR("Error setting up to local apps"); |
2691221a | 709 | } |
1ea11eab MD |
710 | ret = pthread_create(&local_apps.ust_listener, NULL, |
711 | ust_listener_thread, &local_apps); | |
11ff9c7d | 712 | |
8d20bf54 MD |
713 | if (local_apps.allowed) { |
714 | ret = pthread_create(&global_apps.ust_listener, NULL, | |
715 | ust_listener_thread, &global_apps); | |
716 | } else { | |
717 | handle_register_done(&local_apps); | |
718 | } | |
719 | ||
cf12a773 MD |
720 | switch (timeout_mode) { |
721 | case 1: /* timeout wait */ | |
95259bd0 MD |
722 | do { |
723 | ret = sem_timedwait(&constructor_wait, | |
724 | &constructor_timeout); | |
725 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
726 | if (ret < 0 && errno == ETIMEDOUT) { |
727 | ERR("Timed out waiting for ltt-sessiond"); | |
728 | } else { | |
729 | assert(!ret); | |
730 | } | |
731 | break; | |
7b766b16 | 732 | case -1:/* wait forever */ |
95259bd0 MD |
733 | do { |
734 | ret = sem_wait(&constructor_wait); | |
735 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 736 | assert(!ret); |
cf12a773 | 737 | break; |
7b766b16 | 738 | case 0: /* no timeout */ |
cf12a773 | 739 | break; |
11ff9c7d | 740 | } |
2691221a MD |
741 | } |
742 | ||
17dfb34b MD |
743 | static |
744 | void lttng_ust_cleanup(int exiting) | |
745 | { | |
746 | cleanup_sock_info(&global_apps); | |
747 | if (local_apps.allowed) { | |
748 | cleanup_sock_info(&local_apps); | |
749 | } | |
750 | lttng_ust_abi_exit(); | |
751 | ltt_events_exit(); | |
752 | ltt_ring_buffer_client_discard_exit(); | |
753 | ltt_ring_buffer_client_overwrite_exit(); | |
754 | ltt_ring_buffer_metadata_client_exit(); | |
755 | exit_tracepoint(); | |
756 | if (!exiting) { | |
757 | /* Reinitialize values for fork */ | |
758 | sem_count = 2; | |
759 | lttng_ust_comm_should_quit = 0; | |
760 | initialized = 0; | |
761 | } | |
762 | } | |
763 | ||
edaa1431 | 764 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
765 | { |
766 | int ret; | |
767 | ||
9eb62b9c MD |
768 | /* |
769 | * Using pthread_cancel here because: | |
770 | * A) we don't want to hang application teardown. | |
771 | * B) the thread is not allocating any resource. | |
772 | */ | |
1ea11eab MD |
773 | |
774 | /* | |
775 | * Require the communication thread to quit. Synchronize with | |
776 | * mutexes to ensure it is not in a mutex critical section when | |
777 | * pthread_cancel is later called. | |
778 | */ | |
17dfb34b | 779 | ust_lock(); |
1ea11eab | 780 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 781 | ust_unlock(); |
1ea11eab | 782 | |
1ea11eab | 783 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c MD |
784 | if (ret) { |
785 | ERR("Error cancelling global ust listener thread"); | |
2691221a | 786 | } |
8d20bf54 MD |
787 | if (local_apps.allowed) { |
788 | ret = pthread_cancel(local_apps.ust_listener); | |
789 | if (ret) { | |
790 | ERR("Error cancelling local ust listener thread"); | |
791 | } | |
8d20bf54 | 792 | } |
17dfb34b | 793 | lttng_ust_cleanup(1); |
2691221a | 794 | } |
e822f505 MD |
795 | |
796 | /* | |
797 | * We exclude the worker threads across fork and clone (except | |
798 | * CLONE_VM), because these system calls only keep the forking thread | |
799 | * running in the child. Therefore, we don't want to call fork or clone | |
800 | * in the middle of an tracepoint or ust tracing state modification. | |
801 | * Holding this mutex protects these structures across fork and clone. | |
802 | */ | |
803 | void ust_before_fork(ust_fork_info_t *fork_info) | |
804 | { | |
805 | /* | |
806 | * Disable signals. This is to avoid that the child intervenes | |
807 | * before it is properly setup for tracing. It is safer to | |
808 | * disable all signals, because then we know we are not breaking | |
809 | * anything by restoring the original mask. | |
810 | */ | |
811 | sigset_t all_sigs; | |
812 | int ret; | |
813 | ||
814 | /* Disable signals */ | |
815 | sigfillset(&all_sigs); | |
816 | ret = sigprocmask(SIG_BLOCK, &all_sigs, &fork_info->orig_sigs); | |
817 | if (ret == -1) { | |
818 | PERROR("sigprocmask"); | |
819 | } | |
17dfb34b | 820 | ust_lock(); |
e822f505 MD |
821 | rcu_bp_before_fork(); |
822 | } | |
823 | ||
824 | static void ust_after_fork_common(ust_fork_info_t *fork_info) | |
825 | { | |
826 | int ret; | |
827 | ||
17dfb34b MD |
828 | DBG("process %d", getpid()); |
829 | ust_unlock(); | |
e822f505 MD |
830 | /* Restore signals */ |
831 | ret = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL); | |
832 | if (ret == -1) { | |
833 | PERROR("sigprocmask"); | |
834 | } | |
835 | } | |
836 | ||
837 | void ust_after_fork_parent(ust_fork_info_t *fork_info) | |
838 | { | |
17dfb34b | 839 | DBG("process %d", getpid()); |
e822f505 MD |
840 | rcu_bp_after_fork_parent(); |
841 | /* Release mutexes and reenable signals */ | |
842 | ust_after_fork_common(fork_info); | |
843 | } | |
844 | ||
17dfb34b MD |
845 | /* |
846 | * After fork, in the child, we need to cleanup all the leftover state, | |
847 | * except the worker thread which already magically disappeared thanks | |
848 | * to the weird Linux fork semantics. After tyding up, we call | |
849 | * lttng_ust_init() again to start over as a new PID. | |
850 | * | |
851 | * This is meant for forks() that have tracing in the child between the | |
852 | * fork and following exec call (if there is any). | |
853 | */ | |
e822f505 MD |
854 | void ust_after_fork_child(ust_fork_info_t *fork_info) |
855 | { | |
17dfb34b | 856 | DBG("process %d", getpid()); |
e822f505 MD |
857 | /* Release urcu mutexes */ |
858 | rcu_bp_after_fork_child(); | |
17dfb34b | 859 | lttng_ust_cleanup(0); |
e822f505 MD |
860 | /* Release mutexes and reenable signals */ |
861 | ust_after_fork_common(fork_info); | |
318dfea9 | 862 | lttng_ust_init(); |
e822f505 | 863 | } |