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> |
c117fb1b | 40 | #include <urcu/compiler.h> |
1ea11eab | 41 | |
4318ae1b | 42 | #include <lttng/ust-events.h> |
4318ae1b | 43 | #include <lttng/ust-abi.h> |
4318ae1b | 44 | #include <lttng/ust.h> |
44c72f10 MD |
45 | #include <ust-comm.h> |
46 | #include <usterr-signal-safe.h> | |
47 | #include "tracepoint-internal.h" | |
b751f722 | 48 | #include "ltt-tracer-core.h" |
edaa1431 MD |
49 | |
50 | /* | |
51 | * Has lttng ust comm constructor been called ? | |
52 | */ | |
53 | static int initialized; | |
54 | ||
1ea11eab | 55 | /* |
17dfb34b MD |
56 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
57 | * Held when handling a command, also held by fork() to deal with | |
58 | * removal of threads, and by exit path. | |
1ea11eab | 59 | */ |
1ea11eab MD |
60 | |
61 | /* Should the ust comm thread quit ? */ | |
62 | static int lttng_ust_comm_should_quit; | |
63 | ||
11ff9c7d MD |
64 | /* |
65 | * Wait for either of these before continuing to the main | |
66 | * program: | |
67 | * - the register_done message from sessiond daemon | |
68 | * (will let the sessiond daemon enable sessions before main | |
69 | * starts.) | |
70 | * - sessiond daemon is not reachable. | |
71 | * - timeout (ensuring applications are resilient to session | |
72 | * daemon problems). | |
73 | */ | |
74 | static sem_t constructor_wait; | |
950aab0c MD |
75 | /* |
76 | * Doing this for both the global and local sessiond. | |
77 | */ | |
95259bd0 | 78 | static int sem_count = { 2 }; |
11ff9c7d | 79 | |
1ea11eab MD |
80 | /* |
81 | * Info about socket and associated listener thread. | |
82 | */ | |
83 | struct sock_info { | |
11ff9c7d | 84 | const char *name; |
1ea11eab | 85 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 86 | int root_handle; |
8d20bf54 MD |
87 | int constructor_sem_posted; |
88 | int allowed; | |
44e073f5 | 89 | int global; |
7fc90dca MD |
90 | |
91 | char sock_path[PATH_MAX]; | |
92 | int socket; | |
93 | ||
94 | char wait_shm_path[PATH_MAX]; | |
95 | char *wait_shm_mmap; | |
1ea11eab | 96 | }; |
2691221a MD |
97 | |
98 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 99 | struct sock_info global_apps = { |
11ff9c7d | 100 | .name = "global", |
44e073f5 | 101 | .global = 1, |
7fc90dca | 102 | |
46050b1a | 103 | .root_handle = -1, |
8d20bf54 | 104 | .allowed = 1, |
7fc90dca MD |
105 | |
106 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
107 | .socket = -1, | |
108 | ||
109 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 110 | }; |
2691221a MD |
111 | |
112 | /* TODO: allow global_apps_sock_path override */ | |
113 | ||
1ea11eab | 114 | struct sock_info local_apps = { |
11ff9c7d | 115 | .name = "local", |
44e073f5 | 116 | .global = 0, |
46050b1a | 117 | .root_handle = -1, |
8d20bf54 | 118 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
119 | |
120 | .socket = -1, | |
1ea11eab | 121 | }; |
2691221a | 122 | |
37ed587a MD |
123 | static int wait_poll_fallback; |
124 | ||
edaa1431 MD |
125 | extern void ltt_ring_buffer_client_overwrite_init(void); |
126 | extern void ltt_ring_buffer_client_discard_init(void); | |
127 | extern void ltt_ring_buffer_metadata_client_init(void); | |
128 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
129 | extern void ltt_ring_buffer_client_discard_exit(void); | |
130 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
131 | ||
2691221a | 132 | static |
8d20bf54 | 133 | int setup_local_apps(void) |
2691221a MD |
134 | { |
135 | const char *home_dir; | |
7fc90dca | 136 | uid_t uid; |
2691221a | 137 | |
7fc90dca | 138 | uid = getuid(); |
8d20bf54 MD |
139 | /* |
140 | * Disallow per-user tracing for setuid binaries. | |
141 | */ | |
7fc90dca | 142 | if (uid != geteuid()) { |
8d20bf54 | 143 | local_apps.allowed = 0; |
d0a1ae63 | 144 | return 0; |
8d20bf54 MD |
145 | } else { |
146 | local_apps.allowed = 1; | |
147 | } | |
2691221a MD |
148 | home_dir = (const char *) getenv("HOME"); |
149 | if (!home_dir) | |
150 | return -ENOENT; | |
1ea11eab | 151 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 152 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
153 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
154 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
155 | return 0; |
156 | } | |
157 | ||
158 | static | |
159 | int register_app_to_sessiond(int socket) | |
160 | { | |
161 | ssize_t ret; | |
2629549e | 162 | int prctl_ret; |
2691221a | 163 | struct { |
e44418f3 MD |
164 | uint32_t major; |
165 | uint32_t minor; | |
2691221a | 166 | pid_t pid; |
5c33bde8 | 167 | pid_t ppid; |
2691221a | 168 | uid_t uid; |
83610856 | 169 | gid_t gid; |
c117fb1b | 170 | uint32_t bits_per_long; |
2629549e | 171 | char name[16]; /* process name */ |
2691221a MD |
172 | } reg_msg; |
173 | ||
e44418f3 MD |
174 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
175 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 176 | reg_msg.pid = getpid(); |
5c33bde8 | 177 | reg_msg.ppid = getppid(); |
2691221a | 178 | reg_msg.uid = getuid(); |
83610856 | 179 | reg_msg.gid = getgid(); |
c117fb1b | 180 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
2629549e MD |
181 | prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0); |
182 | if (prctl_ret) { | |
183 | ERR("Error executing prctl"); | |
184 | return -errno; | |
185 | } | |
2691221a | 186 | |
57773204 | 187 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
188 | if (ret >= 0 && ret != sizeof(reg_msg)) |
189 | return -EIO; | |
190 | return ret; | |
191 | } | |
192 | ||
d9e99d10 | 193 | static |
57773204 | 194 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 195 | { |
9eb62b9c | 196 | ssize_t len; |
d3a492d1 | 197 | |
57773204 | 198 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 199 | switch (len) { |
a4be8962 | 200 | case sizeof(*lur): |
d3a492d1 MD |
201 | DBG("message successfully sent"); |
202 | return 0; | |
203 | case -1: | |
204 | if (errno == ECONNRESET) { | |
205 | printf("remote end closed connection\n"); | |
206 | return 0; | |
207 | } | |
208 | return -1; | |
209 | default: | |
210 | printf("incorrect message size: %zd\n", len); | |
211 | return -1; | |
212 | } | |
213 | } | |
214 | ||
215 | static | |
edaa1431 | 216 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
217 | { |
218 | int ret; | |
219 | ||
edaa1431 MD |
220 | if (sock_info->constructor_sem_posted) |
221 | return 0; | |
222 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
223 | if (uatomic_read(&sem_count) <= 0) { |
224 | return 0; | |
225 | } | |
95259bd0 MD |
226 | ret = uatomic_add_return(&sem_count, -1); |
227 | if (ret == 0) { | |
228 | ret = sem_post(&constructor_wait); | |
229 | assert(!ret); | |
230 | } | |
11ff9c7d MD |
231 | return 0; |
232 | } | |
233 | ||
234 | static | |
235 | int handle_message(struct sock_info *sock_info, | |
57773204 | 236 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 237 | { |
1ea11eab | 238 | int ret = 0; |
b61ce3b2 | 239 | const struct lttng_ust_objd_ops *ops; |
57773204 | 240 | struct ustcomm_ust_reply lur; |
193183fb | 241 | int shm_fd, wait_fd; |
1ea11eab | 242 | |
17dfb34b | 243 | ust_lock(); |
1ea11eab | 244 | |
46050b1a MD |
245 | memset(&lur, 0, sizeof(lur)); |
246 | ||
1ea11eab | 247 | if (lttng_ust_comm_should_quit) { |
46050b1a | 248 | ret = -EPERM; |
1ea11eab MD |
249 | goto end; |
250 | } | |
9eb62b9c | 251 | |
46050b1a MD |
252 | ops = objd_ops(lum->handle); |
253 | if (!ops) { | |
254 | ret = -ENOENT; | |
255 | goto end; | |
1ea11eab | 256 | } |
46050b1a MD |
257 | |
258 | switch (lum->cmd) { | |
11ff9c7d MD |
259 | case LTTNG_UST_REGISTER_DONE: |
260 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 261 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
262 | else |
263 | ret = -EINVAL; | |
264 | break; | |
46050b1a MD |
265 | case LTTNG_UST_RELEASE: |
266 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
267 | ret = -EPERM; | |
268 | else | |
d4419b81 | 269 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 MD |
270 | break; |
271 | default: | |
46050b1a MD |
272 | if (ops->cmd) |
273 | ret = ops->cmd(lum->handle, lum->cmd, | |
274 | (unsigned long) &lum->u); | |
275 | else | |
276 | ret = -ENOSYS; | |
277 | break; | |
d9e99d10 | 278 | } |
46050b1a | 279 | |
1ea11eab | 280 | end: |
46050b1a MD |
281 | lur.handle = lum->handle; |
282 | lur.cmd = lum->cmd; | |
283 | lur.ret_val = ret; | |
284 | if (ret >= 0) { | |
57773204 | 285 | lur.ret_code = USTCOMM_OK; |
46050b1a | 286 | } else { |
57773204 | 287 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 288 | lur.ret_code = ret; |
46050b1a | 289 | } |
193183fb MD |
290 | switch (lum->cmd) { |
291 | case LTTNG_UST_STREAM: | |
381c0f1e MD |
292 | /* |
293 | * Special-case reply to send stream info. | |
294 | * Use lum.u output. | |
295 | */ | |
296 | lur.u.stream.memory_map_size = lum->u.stream.memory_map_size; | |
193183fb MD |
297 | shm_fd = lum->u.stream.shm_fd; |
298 | wait_fd = lum->u.stream.wait_fd; | |
299 | break; | |
824f40b8 | 300 | case LTTNG_UST_METADATA: |
193183fb MD |
301 | case LTTNG_UST_CHANNEL: |
302 | lur.u.channel.memory_map_size = lum->u.channel.memory_map_size; | |
303 | shm_fd = lum->u.channel.shm_fd; | |
304 | wait_fd = lum->u.channel.wait_fd; | |
305 | break; | |
23c8854a | 306 | case LTTNG_UST_TRACER_VERSION: |
57773204 MD |
307 | lur.u.version = lum->u.version; |
308 | break; | |
b115631f | 309 | case LTTNG_UST_TRACEPOINT_LIST_GET: |
cbef6901 | 310 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); |
b115631f | 311 | break; |
381c0f1e | 312 | } |
46050b1a | 313 | ret = send_reply(sock, &lur); |
193183fb MD |
314 | if (ret < 0) { |
315 | perror("error sending reply"); | |
316 | goto error; | |
317 | } | |
46050b1a | 318 | |
824f40b8 MD |
319 | if ((lum->cmd == LTTNG_UST_STREAM |
320 | || lum->cmd == LTTNG_UST_CHANNEL | |
321 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 322 | && lur.ret_code == USTCOMM_OK) { |
381c0f1e | 323 | /* we also need to send the file descriptors. */ |
57773204 | 324 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 325 | &shm_fd, &shm_fd, |
381c0f1e MD |
326 | 1, sizeof(int)); |
327 | if (ret < 0) { | |
328 | perror("send shm_fd"); | |
329 | goto error; | |
330 | } | |
57773204 | 331 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 332 | &wait_fd, &wait_fd, |
381c0f1e MD |
333 | 1, sizeof(int)); |
334 | if (ret < 0) { | |
335 | perror("send wait_fd"); | |
336 | goto error; | |
337 | } | |
338 | } | |
339 | error: | |
17dfb34b | 340 | ust_unlock(); |
1ea11eab | 341 | return ret; |
d9e99d10 MD |
342 | } |
343 | ||
46050b1a MD |
344 | static |
345 | void cleanup_sock_info(struct sock_info *sock_info) | |
346 | { | |
347 | int ret; | |
348 | ||
349 | if (sock_info->socket != -1) { | |
350 | ret = close(sock_info->socket); | |
351 | if (ret) { | |
7fc90dca | 352 | ERR("Error closing apps socket"); |
46050b1a MD |
353 | } |
354 | sock_info->socket = -1; | |
355 | } | |
356 | if (sock_info->root_handle != -1) { | |
d4419b81 | 357 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
358 | if (ret) { |
359 | ERR("Error unref root handle"); | |
360 | } | |
361 | sock_info->root_handle = -1; | |
362 | } | |
318dfea9 | 363 | sock_info->constructor_sem_posted = 0; |
7fc90dca MD |
364 | if (sock_info->wait_shm_mmap) { |
365 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); | |
366 | if (ret) { | |
367 | ERR("Error unmapping wait shm"); | |
368 | } | |
369 | sock_info->wait_shm_mmap = NULL; | |
370 | } | |
371 | } | |
372 | ||
58d4b2a2 | 373 | /* |
33bbeb90 MD |
374 | * Using fork to set umask in the child process (not multi-thread safe). |
375 | * We deal with the shm_open vs ftruncate race (happening when the | |
376 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
377 | * safety against shm_unlink) by simply letting the mmap fail and | |
378 | * retrying after a few seconds. | |
379 | * For global shm, everybody has rw access to it until the sessiond | |
380 | * starts. | |
58d4b2a2 | 381 | */ |
7fc90dca | 382 | static |
58d4b2a2 | 383 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 384 | { |
7fc90dca | 385 | int wait_shm_fd, ret; |
58d4b2a2 | 386 | pid_t pid; |
44e073f5 | 387 | |
58d4b2a2 | 388 | /* |
33bbeb90 | 389 | * Try to open read-only. |
58d4b2a2 | 390 | */ |
33bbeb90 | 391 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
392 | if (wait_shm_fd >= 0) { |
393 | goto end; | |
394 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
395 | /* | |
33bbeb90 MD |
396 | * Real-only open did not work, and it's not because the |
397 | * entry was not present. It's a failure that prohibits | |
398 | * using shm. | |
58d4b2a2 | 399 | */ |
7fc90dca | 400 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 401 | goto end; |
7fc90dca MD |
402 | } |
403 | /* | |
58d4b2a2 MD |
404 | * If the open failed because the file did not exist, try |
405 | * creating it ourself. | |
7fc90dca | 406 | */ |
58d4b2a2 MD |
407 | pid = fork(); |
408 | if (pid > 0) { | |
409 | int status; | |
410 | ||
411 | /* | |
412 | * Parent: wait for child to return, in which case the | |
413 | * shared memory map will have been created. | |
414 | */ | |
415 | pid = wait(&status); | |
416 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { | |
417 | wait_shm_fd = -1; | |
418 | goto end; | |
7fc90dca | 419 | } |
58d4b2a2 MD |
420 | /* |
421 | * Try to open read-only again after creation. | |
422 | */ | |
33bbeb90 | 423 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
424 | if (wait_shm_fd < 0) { |
425 | /* | |
426 | * Real-only open did not work. It's a failure | |
427 | * that prohibits using shm. | |
428 | */ | |
429 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
430 | goto end; | |
431 | } | |
432 | goto end; | |
433 | } else if (pid == 0) { | |
434 | int create_mode; | |
435 | ||
436 | /* Child */ | |
33bbeb90 | 437 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 438 | if (sock_info->global) |
33bbeb90 | 439 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
440 | /* |
441 | * We're alone in a child process, so we can modify the | |
442 | * process-wide umask. | |
443 | */ | |
33bbeb90 | 444 | umask(~create_mode); |
58d4b2a2 | 445 | /* |
33bbeb90 MD |
446 | * Try creating shm (or get rw access). |
447 | * We don't do an exclusive open, because we allow other | |
448 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
449 | */ |
450 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
451 | O_RDWR | O_CREAT, create_mode); | |
452 | if (wait_shm_fd >= 0) { | |
453 | ret = ftruncate(wait_shm_fd, mmap_size); | |
454 | if (ret) { | |
455 | PERROR("ftruncate"); | |
456 | exit(EXIT_FAILURE); | |
457 | } | |
58d4b2a2 MD |
458 | exit(EXIT_SUCCESS); |
459 | } | |
33bbeb90 MD |
460 | /* |
461 | * For local shm, we need to have rw access to accept | |
462 | * opening it: this means the local sessiond will be | |
463 | * able to wake us up. For global shm, we open it even | |
464 | * if rw access is not granted, because the root.root | |
465 | * sessiond will be able to override all rights and wake | |
466 | * us up. | |
467 | */ | |
468 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
469 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
470 | exit(EXIT_FAILURE); | |
471 | } | |
472 | /* | |
33bbeb90 MD |
473 | * The shm exists, but we cannot open it RW. Report |
474 | * success. | |
58d4b2a2 MD |
475 | */ |
476 | exit(EXIT_SUCCESS); | |
477 | } else { | |
478 | return -1; | |
7fc90dca | 479 | } |
58d4b2a2 | 480 | end: |
33bbeb90 MD |
481 | if (wait_shm_fd >= 0 && !sock_info->global) { |
482 | struct stat statbuf; | |
483 | ||
484 | /* | |
485 | * Ensure that our user is the owner of the shm file for | |
486 | * local shm. If we do not own the file, it means our | |
487 | * sessiond will not have access to wake us up (there is | |
488 | * probably a rogue process trying to fake our | |
489 | * sessiond). Fallback to polling method in this case. | |
490 | */ | |
491 | ret = fstat(wait_shm_fd, &statbuf); | |
492 | if (ret) { | |
493 | PERROR("fstat"); | |
494 | goto error_close; | |
495 | } | |
496 | if (statbuf.st_uid != getuid()) | |
497 | goto error_close; | |
498 | } | |
58d4b2a2 | 499 | return wait_shm_fd; |
33bbeb90 MD |
500 | |
501 | error_close: | |
502 | ret = close(wait_shm_fd); | |
503 | if (ret) { | |
504 | PERROR("Error closing fd"); | |
505 | } | |
506 | return -1; | |
58d4b2a2 MD |
507 | } |
508 | ||
509 | static | |
510 | char *get_map_shm(struct sock_info *sock_info) | |
511 | { | |
512 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
513 | int wait_shm_fd, ret; | |
514 | char *wait_shm_mmap; | |
515 | ||
516 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
517 | if (wait_shm_fd < 0) { | |
518 | goto error; | |
44e073f5 | 519 | } |
7fc90dca MD |
520 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
521 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
522 | /* close shm fd immediately after taking the mmap reference */ |
523 | ret = close(wait_shm_fd); | |
524 | if (ret) { | |
33bbeb90 MD |
525 | PERROR("Error closing fd"); |
526 | } | |
527 | if (wait_shm_mmap == MAP_FAILED) { | |
528 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
529 | goto error; | |
7fc90dca MD |
530 | } |
531 | return wait_shm_mmap; | |
532 | ||
533 | error: | |
534 | return NULL; | |
535 | } | |
536 | ||
537 | static | |
538 | void wait_for_sessiond(struct sock_info *sock_info) | |
539 | { | |
80e2814b MD |
540 | int ret; |
541 | ||
7fc90dca MD |
542 | ust_lock(); |
543 | if (lttng_ust_comm_should_quit) { | |
544 | goto quit; | |
545 | } | |
37ed587a MD |
546 | if (wait_poll_fallback) { |
547 | goto error; | |
548 | } | |
7fc90dca MD |
549 | if (!sock_info->wait_shm_mmap) { |
550 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
551 | if (!sock_info->wait_shm_mmap) | |
552 | goto error; | |
553 | } | |
554 | ust_unlock(); | |
555 | ||
556 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
557 | /* Wait for futex wakeup */ |
558 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
559 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
560 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 561 | if (ret < 0) { |
37ed587a MD |
562 | if (errno == EFAULT) { |
563 | wait_poll_fallback = 1; | |
a8b870ad | 564 | DBG( |
37ed587a MD |
565 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
566 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
567 | "Please upgrade your kernel " | |
568 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
569 | "mainline). LTTng-UST will use polling mode fallback."); | |
1cb5dd98 | 570 | PERROR("futex"); |
37ed587a | 571 | } |
80e2814b MD |
572 | } |
573 | } | |
7fc90dca MD |
574 | return; |
575 | ||
576 | quit: | |
577 | ust_unlock(); | |
578 | return; | |
579 | ||
580 | error: | |
581 | ust_unlock(); | |
7fc90dca | 582 | return; |
46050b1a MD |
583 | } |
584 | ||
1ea11eab MD |
585 | /* |
586 | * This thread does not allocate any resource, except within | |
587 | * handle_message, within mutex protection. This mutex protects against | |
588 | * fork and exit. | |
589 | * The other moment it allocates resources is at socket connexion, which | |
590 | * is also protected by the mutex. | |
591 | */ | |
d9e99d10 MD |
592 | static |
593 | void *ust_listener_thread(void *arg) | |
594 | { | |
1ea11eab | 595 | struct sock_info *sock_info = arg; |
c0eedf81 | 596 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 597 | |
9eb62b9c MD |
598 | /* Restart trying to connect to the session daemon */ |
599 | restart: | |
c0eedf81 MD |
600 | if (prev_connect_failed) { |
601 | /* Wait for sessiond availability with pipe */ | |
602 | wait_for_sessiond(sock_info); | |
603 | if (has_waited) { | |
604 | has_waited = 0; | |
605 | /* | |
606 | * Sleep for 5 seconds before retrying after a | |
607 | * sequence of failure / wait / failure. This | |
608 | * deals with a killed or broken session daemon. | |
609 | */ | |
610 | sleep(5); | |
611 | } | |
612 | has_waited = 1; | |
613 | prev_connect_failed = 0; | |
614 | } | |
17dfb34b | 615 | ust_lock(); |
1ea11eab MD |
616 | |
617 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 618 | ust_unlock(); |
1ea11eab MD |
619 | goto quit; |
620 | } | |
9eb62b9c | 621 | |
1ea11eab MD |
622 | if (sock_info->socket != -1) { |
623 | ret = close(sock_info->socket); | |
624 | if (ret) { | |
11ff9c7d | 625 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
626 | } |
627 | sock_info->socket = -1; | |
628 | } | |
46050b1a | 629 | |
9eb62b9c | 630 | /* Register */ |
57773204 | 631 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 632 | if (ret < 0) { |
4d3c9523 | 633 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 634 | prev_connect_failed = 1; |
11ff9c7d MD |
635 | /* |
636 | * If we cannot find the sessiond daemon, don't delay | |
637 | * constructor execution. | |
638 | */ | |
edaa1431 | 639 | ret = handle_register_done(sock_info); |
11ff9c7d | 640 | assert(!ret); |
17dfb34b | 641 | ust_unlock(); |
1ea11eab | 642 | goto restart; |
46050b1a MD |
643 | } |
644 | ||
645 | sock_info->socket = sock = ret; | |
646 | ||
647 | /* | |
648 | * Create only one root handle per listener thread for the whole | |
649 | * process lifetime. | |
650 | */ | |
651 | if (sock_info->root_handle == -1) { | |
652 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 653 | if (ret < 0) { |
46050b1a | 654 | ERR("Error creating root handle"); |
17dfb34b | 655 | ust_unlock(); |
46050b1a MD |
656 | goto quit; |
657 | } | |
658 | sock_info->root_handle = ret; | |
9eb62b9c | 659 | } |
1ea11eab | 660 | |
9eb62b9c MD |
661 | ret = register_app_to_sessiond(sock); |
662 | if (ret < 0) { | |
11ff9c7d | 663 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 664 | prev_connect_failed = 1; |
11ff9c7d MD |
665 | /* |
666 | * If we cannot register to the sessiond daemon, don't | |
667 | * delay constructor execution. | |
668 | */ | |
edaa1431 | 669 | ret = handle_register_done(sock_info); |
11ff9c7d | 670 | assert(!ret); |
17dfb34b | 671 | ust_unlock(); |
9eb62b9c MD |
672 | goto restart; |
673 | } | |
17dfb34b | 674 | ust_unlock(); |
46050b1a | 675 | |
d9e99d10 MD |
676 | for (;;) { |
677 | ssize_t len; | |
57773204 | 678 | struct ustcomm_ust_msg lum; |
d9e99d10 | 679 | |
57773204 | 680 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
681 | switch (len) { |
682 | case 0: /* orderly shutdown */ | |
11ff9c7d | 683 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
684 | ust_lock(); |
685 | /* | |
686 | * Either sessiond has shutdown or refused us by closing the socket. | |
687 | * In either case, we don't want to delay construction execution, | |
688 | * and we need to wait before retry. | |
689 | */ | |
690 | prev_connect_failed = 1; | |
691 | /* | |
692 | * If we cannot register to the sessiond daemon, don't | |
693 | * delay constructor execution. | |
694 | */ | |
695 | ret = handle_register_done(sock_info); | |
696 | assert(!ret); | |
697 | ust_unlock(); | |
d9e99d10 | 698 | goto end; |
e7723462 | 699 | case sizeof(lum): |
d9e99d10 | 700 | DBG("message received\n"); |
11ff9c7d | 701 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 702 | if (ret < 0) { |
11ff9c7d | 703 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
704 | } |
705 | continue; | |
706 | case -1: | |
8236ba10 | 707 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 708 | if (errno == ECONNRESET) { |
11ff9c7d | 709 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
710 | goto end; |
711 | } | |
712 | goto end; | |
713 | default: | |
11ff9c7d | 714 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
715 | continue; |
716 | } | |
717 | ||
718 | } | |
719 | end: | |
9eb62b9c | 720 | goto restart; /* try to reconnect */ |
1ea11eab | 721 | quit: |
d9e99d10 MD |
722 | return NULL; |
723 | } | |
724 | ||
cf12a773 MD |
725 | /* |
726 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
727 | */ | |
11ff9c7d MD |
728 | static |
729 | int get_timeout(struct timespec *constructor_timeout) | |
730 | { | |
cf12a773 MD |
731 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
732 | char *str_delay; | |
11ff9c7d MD |
733 | int ret; |
734 | ||
69400ac4 | 735 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
736 | if (str_delay) { |
737 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
738 | } | |
739 | ||
740 | switch (constructor_delay_ms) { | |
741 | case -1:/* fall-through */ | |
742 | case 0: | |
743 | return constructor_delay_ms; | |
744 | default: | |
745 | break; | |
746 | } | |
747 | ||
748 | /* | |
749 | * If we are unable to find the current time, don't wait. | |
750 | */ | |
751 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
752 | if (ret) { | |
753 | return -1; | |
754 | } | |
95259bd0 MD |
755 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
756 | constructor_timeout->tv_nsec += | |
757 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
758 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
759 | constructor_timeout->tv_sec++; | |
760 | constructor_timeout->tv_nsec -= 1000000000UL; | |
761 | } | |
cf12a773 | 762 | return 1; |
11ff9c7d | 763 | } |
d9e99d10 | 764 | |
2691221a MD |
765 | /* |
766 | * sessiond monitoring thread: monitor presence of global and per-user | |
767 | * sessiond by polling the application common named pipe. | |
768 | */ | |
769 | /* TODO */ | |
770 | ||
edaa1431 | 771 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 772 | { |
11ff9c7d | 773 | struct timespec constructor_timeout; |
cf12a773 | 774 | int timeout_mode; |
2691221a MD |
775 | int ret; |
776 | ||
edaa1431 MD |
777 | if (uatomic_xchg(&initialized, 1) == 1) |
778 | return; | |
779 | ||
780 | /* | |
781 | * We want precise control over the order in which we construct | |
782 | * our sub-libraries vs starting to receive commands from | |
783 | * sessiond (otherwise leading to errors when trying to create | |
784 | * sessiond before the init functions are completed). | |
785 | */ | |
2691221a | 786 | init_usterr(); |
edaa1431 MD |
787 | init_tracepoint(); |
788 | ltt_ring_buffer_metadata_client_init(); | |
789 | ltt_ring_buffer_client_overwrite_init(); | |
790 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 791 | |
cf12a773 | 792 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 793 | |
95259bd0 | 794 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
795 | assert(!ret); |
796 | ||
8d20bf54 | 797 | ret = setup_local_apps(); |
2691221a | 798 | if (ret) { |
8d20bf54 | 799 | ERR("Error setting up to local apps"); |
2691221a | 800 | } |
1ea11eab MD |
801 | ret = pthread_create(&local_apps.ust_listener, NULL, |
802 | ust_listener_thread, &local_apps); | |
11ff9c7d | 803 | |
8d20bf54 MD |
804 | if (local_apps.allowed) { |
805 | ret = pthread_create(&global_apps.ust_listener, NULL, | |
806 | ust_listener_thread, &global_apps); | |
807 | } else { | |
808 | handle_register_done(&local_apps); | |
809 | } | |
810 | ||
cf12a773 MD |
811 | switch (timeout_mode) { |
812 | case 1: /* timeout wait */ | |
95259bd0 MD |
813 | do { |
814 | ret = sem_timedwait(&constructor_wait, | |
815 | &constructor_timeout); | |
816 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
817 | if (ret < 0 && errno == ETIMEDOUT) { |
818 | ERR("Timed out waiting for ltt-sessiond"); | |
819 | } else { | |
820 | assert(!ret); | |
821 | } | |
822 | break; | |
7b766b16 | 823 | case -1:/* wait forever */ |
95259bd0 MD |
824 | do { |
825 | ret = sem_wait(&constructor_wait); | |
826 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 827 | assert(!ret); |
cf12a773 | 828 | break; |
7b766b16 | 829 | case 0: /* no timeout */ |
cf12a773 | 830 | break; |
11ff9c7d | 831 | } |
2691221a MD |
832 | } |
833 | ||
17dfb34b MD |
834 | static |
835 | void lttng_ust_cleanup(int exiting) | |
836 | { | |
837 | cleanup_sock_info(&global_apps); | |
838 | if (local_apps.allowed) { | |
839 | cleanup_sock_info(&local_apps); | |
840 | } | |
841 | lttng_ust_abi_exit(); | |
003fedf4 | 842 | lttng_ust_events_exit(); |
17dfb34b MD |
843 | ltt_ring_buffer_client_discard_exit(); |
844 | ltt_ring_buffer_client_overwrite_exit(); | |
845 | ltt_ring_buffer_metadata_client_exit(); | |
846 | exit_tracepoint(); | |
847 | if (!exiting) { | |
848 | /* Reinitialize values for fork */ | |
849 | sem_count = 2; | |
850 | lttng_ust_comm_should_quit = 0; | |
851 | initialized = 0; | |
852 | } | |
853 | } | |
854 | ||
edaa1431 | 855 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
856 | { |
857 | int ret; | |
858 | ||
9eb62b9c MD |
859 | /* |
860 | * Using pthread_cancel here because: | |
861 | * A) we don't want to hang application teardown. | |
862 | * B) the thread is not allocating any resource. | |
863 | */ | |
1ea11eab MD |
864 | |
865 | /* | |
866 | * Require the communication thread to quit. Synchronize with | |
867 | * mutexes to ensure it is not in a mutex critical section when | |
868 | * pthread_cancel is later called. | |
869 | */ | |
17dfb34b | 870 | ust_lock(); |
1ea11eab | 871 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 872 | ust_unlock(); |
1ea11eab | 873 | |
1ea11eab | 874 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c MD |
875 | if (ret) { |
876 | ERR("Error cancelling global ust listener thread"); | |
2691221a | 877 | } |
8d20bf54 MD |
878 | if (local_apps.allowed) { |
879 | ret = pthread_cancel(local_apps.ust_listener); | |
880 | if (ret) { | |
881 | ERR("Error cancelling local ust listener thread"); | |
882 | } | |
8d20bf54 | 883 | } |
17dfb34b | 884 | lttng_ust_cleanup(1); |
2691221a | 885 | } |
e822f505 MD |
886 | |
887 | /* | |
888 | * We exclude the worker threads across fork and clone (except | |
889 | * CLONE_VM), because these system calls only keep the forking thread | |
890 | * running in the child. Therefore, we don't want to call fork or clone | |
891 | * in the middle of an tracepoint or ust tracing state modification. | |
892 | * Holding this mutex protects these structures across fork and clone. | |
893 | */ | |
b728d87e | 894 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
895 | { |
896 | /* | |
897 | * Disable signals. This is to avoid that the child intervenes | |
898 | * before it is properly setup for tracing. It is safer to | |
899 | * disable all signals, because then we know we are not breaking | |
900 | * anything by restoring the original mask. | |
901 | */ | |
902 | sigset_t all_sigs; | |
903 | int ret; | |
904 | ||
905 | /* Disable signals */ | |
906 | sigfillset(&all_sigs); | |
b728d87e | 907 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
908 | if (ret == -1) { |
909 | PERROR("sigprocmask"); | |
910 | } | |
17dfb34b | 911 | ust_lock(); |
e822f505 MD |
912 | rcu_bp_before_fork(); |
913 | } | |
914 | ||
b728d87e | 915 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
916 | { |
917 | int ret; | |
918 | ||
17dfb34b MD |
919 | DBG("process %d", getpid()); |
920 | ust_unlock(); | |
e822f505 | 921 | /* Restore signals */ |
23c8854a | 922 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
923 | if (ret == -1) { |
924 | PERROR("sigprocmask"); | |
925 | } | |
926 | } | |
927 | ||
b728d87e | 928 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 929 | { |
17dfb34b | 930 | DBG("process %d", getpid()); |
e822f505 MD |
931 | rcu_bp_after_fork_parent(); |
932 | /* Release mutexes and reenable signals */ | |
b728d87e | 933 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
934 | } |
935 | ||
17dfb34b MD |
936 | /* |
937 | * After fork, in the child, we need to cleanup all the leftover state, | |
938 | * except the worker thread which already magically disappeared thanks | |
939 | * to the weird Linux fork semantics. After tyding up, we call | |
940 | * lttng_ust_init() again to start over as a new PID. | |
941 | * | |
942 | * This is meant for forks() that have tracing in the child between the | |
943 | * fork and following exec call (if there is any). | |
944 | */ | |
b728d87e | 945 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 946 | { |
17dfb34b | 947 | DBG("process %d", getpid()); |
e822f505 MD |
948 | /* Release urcu mutexes */ |
949 | rcu_bp_after_fork_child(); | |
17dfb34b | 950 | lttng_ust_cleanup(0); |
a93bfc45 | 951 | lttng_context_vtid_reset(); |
e822f505 | 952 | /* Release mutexes and reenable signals */ |
b728d87e | 953 | ust_after_fork_common(restore_sigset); |
318dfea9 | 954 | lttng_ust_init(); |
e822f505 | 955 | } |