Commit | Line | Data |
---|---|---|
2691221a MD |
1 | /* |
2 | * lttng-ust-comm.c | |
3 | * | |
4 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> | |
5 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
6 | * | |
7 | * This library is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU Lesser General Public | |
9 | * License as published by the Free Software Foundation; only | |
10 | * version 2.1 of the License. | |
11 | * | |
12 | * This library is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with this library; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
80e2814b | 22 | #define _LGPL_SOURCE |
2691221a MD |
23 | #include <sys/types.h> |
24 | #include <sys/socket.h> | |
7fc90dca MD |
25 | #include <sys/mman.h> |
26 | #include <sys/stat.h> | |
58d4b2a2 MD |
27 | #include <sys/types.h> |
28 | #include <sys/wait.h> | |
7fc90dca | 29 | #include <fcntl.h> |
2691221a MD |
30 | #include <unistd.h> |
31 | #include <errno.h> | |
d9e99d10 | 32 | #include <pthread.h> |
11ff9c7d MD |
33 | #include <semaphore.h> |
34 | #include <time.h> | |
1ea11eab | 35 | #include <assert.h> |
e822f505 | 36 | #include <signal.h> |
95259bd0 | 37 | #include <urcu/uatomic.h> |
80e2814b | 38 | #include <urcu/futex.h> |
c117fb1b | 39 | #include <urcu/compiler.h> |
1ea11eab | 40 | |
4318ae1b | 41 | #include <lttng/ust-events.h> |
4318ae1b | 42 | #include <lttng/ust-abi.h> |
4318ae1b | 43 | #include <lttng/ust.h> |
44c72f10 MD |
44 | #include <ust-comm.h> |
45 | #include <usterr-signal-safe.h> | |
46 | #include "tracepoint-internal.h" | |
b751f722 | 47 | #include "ltt-tracer-core.h" |
48621a42 | 48 | #include "compat.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; | |
162 | struct { | |
e44418f3 MD |
163 | uint32_t major; |
164 | uint32_t minor; | |
2691221a | 165 | pid_t pid; |
5c33bde8 | 166 | pid_t ppid; |
2691221a | 167 | uid_t uid; |
83610856 | 168 | gid_t gid; |
c117fb1b | 169 | uint32_t bits_per_long; |
2629549e | 170 | char name[16]; /* process name */ |
2691221a MD |
171 | } reg_msg; |
172 | ||
e44418f3 MD |
173 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
174 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 175 | reg_msg.pid = getpid(); |
5c33bde8 | 176 | reg_msg.ppid = getppid(); |
2691221a | 177 | reg_msg.uid = getuid(); |
83610856 | 178 | reg_msg.gid = getgid(); |
c117fb1b | 179 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
48621a42 | 180 | lttng_ust_getprocname(reg_msg.name); |
2691221a | 181 | |
57773204 | 182 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
183 | if (ret >= 0 && ret != sizeof(reg_msg)) |
184 | return -EIO; | |
185 | return ret; | |
186 | } | |
187 | ||
d9e99d10 | 188 | static |
57773204 | 189 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 190 | { |
9eb62b9c | 191 | ssize_t len; |
d3a492d1 | 192 | |
57773204 | 193 | len = ustcomm_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; | |
56cd7e2f MD |
218 | if (uatomic_read(&sem_count) <= 0) { |
219 | return 0; | |
220 | } | |
95259bd0 MD |
221 | ret = uatomic_add_return(&sem_count, -1); |
222 | if (ret == 0) { | |
223 | ret = sem_post(&constructor_wait); | |
224 | assert(!ret); | |
225 | } | |
11ff9c7d MD |
226 | return 0; |
227 | } | |
228 | ||
229 | static | |
230 | int handle_message(struct sock_info *sock_info, | |
57773204 | 231 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 232 | { |
1ea11eab | 233 | int ret = 0; |
b61ce3b2 | 234 | const struct lttng_ust_objd_ops *ops; |
57773204 | 235 | struct ustcomm_ust_reply lur; |
193183fb | 236 | int shm_fd, wait_fd; |
ef9ff354 | 237 | union ust_args args; |
1ea11eab | 238 | |
17dfb34b | 239 | ust_lock(); |
1ea11eab | 240 | |
46050b1a MD |
241 | memset(&lur, 0, sizeof(lur)); |
242 | ||
1ea11eab | 243 | if (lttng_ust_comm_should_quit) { |
46050b1a | 244 | ret = -EPERM; |
1ea11eab MD |
245 | goto end; |
246 | } | |
9eb62b9c | 247 | |
46050b1a MD |
248 | ops = objd_ops(lum->handle); |
249 | if (!ops) { | |
250 | ret = -ENOENT; | |
251 | goto end; | |
1ea11eab | 252 | } |
46050b1a MD |
253 | |
254 | switch (lum->cmd) { | |
11ff9c7d MD |
255 | case LTTNG_UST_REGISTER_DONE: |
256 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 257 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
258 | else |
259 | ret = -EINVAL; | |
260 | break; | |
46050b1a MD |
261 | case LTTNG_UST_RELEASE: |
262 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
263 | ret = -EPERM; | |
264 | else | |
d4419b81 | 265 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 MD |
266 | break; |
267 | default: | |
46050b1a MD |
268 | if (ops->cmd) |
269 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
270 | (unsigned long) &lum->u, |
271 | &args); | |
46050b1a MD |
272 | else |
273 | ret = -ENOSYS; | |
274 | break; | |
d9e99d10 | 275 | } |
46050b1a | 276 | |
1ea11eab | 277 | end: |
46050b1a MD |
278 | lur.handle = lum->handle; |
279 | lur.cmd = lum->cmd; | |
280 | lur.ret_val = ret; | |
281 | if (ret >= 0) { | |
57773204 | 282 | lur.ret_code = USTCOMM_OK; |
46050b1a | 283 | } else { |
57773204 | 284 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 285 | lur.ret_code = ret; |
46050b1a | 286 | } |
193183fb MD |
287 | switch (lum->cmd) { |
288 | case LTTNG_UST_STREAM: | |
381c0f1e MD |
289 | /* |
290 | * Special-case reply to send stream info. | |
291 | * Use lum.u output. | |
292 | */ | |
ef9ff354 MD |
293 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; |
294 | shm_fd = *args.stream.shm_fd; | |
295 | wait_fd = *args.stream.wait_fd; | |
193183fb | 296 | break; |
824f40b8 | 297 | case LTTNG_UST_METADATA: |
193183fb | 298 | case LTTNG_UST_CHANNEL: |
ef9ff354 MD |
299 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; |
300 | shm_fd = *args.channel.shm_fd; | |
301 | wait_fd = *args.channel.wait_fd; | |
193183fb | 302 | break; |
23c8854a | 303 | case LTTNG_UST_TRACER_VERSION: |
57773204 MD |
304 | lur.u.version = lum->u.version; |
305 | break; | |
b115631f | 306 | case LTTNG_UST_TRACEPOINT_LIST_GET: |
cbef6901 | 307 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); |
b115631f | 308 | break; |
381c0f1e | 309 | } |
46050b1a | 310 | ret = send_reply(sock, &lur); |
193183fb MD |
311 | if (ret < 0) { |
312 | perror("error sending reply"); | |
313 | goto error; | |
314 | } | |
46050b1a | 315 | |
824f40b8 MD |
316 | if ((lum->cmd == LTTNG_UST_STREAM |
317 | || lum->cmd == LTTNG_UST_CHANNEL | |
318 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 319 | && lur.ret_code == USTCOMM_OK) { |
381c0f1e | 320 | /* we also need to send the file descriptors. */ |
57773204 | 321 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 322 | &shm_fd, &shm_fd, |
381c0f1e MD |
323 | 1, sizeof(int)); |
324 | if (ret < 0) { | |
325 | perror("send shm_fd"); | |
326 | goto error; | |
327 | } | |
57773204 | 328 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 329 | &wait_fd, &wait_fd, |
381c0f1e MD |
330 | 1, sizeof(int)); |
331 | if (ret < 0) { | |
332 | perror("send wait_fd"); | |
333 | goto error; | |
334 | } | |
335 | } | |
ef9ff354 MD |
336 | /* |
337 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
338 | * sent to the sessiond. We can therefore close those fds. Note |
339 | * that we keep the write side of the wait_fd open, but close | |
340 | * the read side. | |
ef9ff354 MD |
341 | */ |
342 | if (lur.ret_code == USTCOMM_OK) { | |
343 | switch (lum->cmd) { | |
344 | case LTTNG_UST_STREAM: | |
345 | if (shm_fd >= 0) { | |
346 | ret = close(shm_fd); | |
347 | if (ret) { | |
348 | PERROR("Error closing stream shm_fd"); | |
349 | } | |
350 | *args.stream.shm_fd = -1; | |
351 | } | |
352 | if (wait_fd >= 0) { | |
353 | ret = close(wait_fd); | |
354 | if (ret) { | |
355 | PERROR("Error closing stream wait_fd"); | |
356 | } | |
357 | *args.stream.wait_fd = -1; | |
358 | } | |
359 | break; | |
360 | case LTTNG_UST_METADATA: | |
361 | case LTTNG_UST_CHANNEL: | |
362 | if (shm_fd >= 0) { | |
363 | ret = close(shm_fd); | |
364 | if (ret) { | |
365 | PERROR("Error closing channel shm_fd"); | |
366 | } | |
367 | *args.channel.shm_fd = -1; | |
368 | } | |
369 | if (wait_fd >= 0) { | |
370 | ret = close(wait_fd); | |
371 | if (ret) { | |
372 | PERROR("Error closing channel wait_fd"); | |
373 | } | |
374 | *args.channel.wait_fd = -1; | |
375 | } | |
376 | break; | |
377 | } | |
378 | } | |
379 | ||
381c0f1e | 380 | error: |
17dfb34b | 381 | ust_unlock(); |
1ea11eab | 382 | return ret; |
d9e99d10 MD |
383 | } |
384 | ||
46050b1a MD |
385 | static |
386 | void cleanup_sock_info(struct sock_info *sock_info) | |
387 | { | |
388 | int ret; | |
389 | ||
390 | if (sock_info->socket != -1) { | |
391 | ret = close(sock_info->socket); | |
392 | if (ret) { | |
7fc90dca | 393 | ERR("Error closing apps socket"); |
46050b1a MD |
394 | } |
395 | sock_info->socket = -1; | |
396 | } | |
397 | if (sock_info->root_handle != -1) { | |
d4419b81 | 398 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
399 | if (ret) { |
400 | ERR("Error unref root handle"); | |
401 | } | |
402 | sock_info->root_handle = -1; | |
403 | } | |
318dfea9 | 404 | sock_info->constructor_sem_posted = 0; |
7fc90dca MD |
405 | if (sock_info->wait_shm_mmap) { |
406 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); | |
407 | if (ret) { | |
408 | ERR("Error unmapping wait shm"); | |
409 | } | |
410 | sock_info->wait_shm_mmap = NULL; | |
411 | } | |
412 | } | |
413 | ||
58d4b2a2 | 414 | /* |
33bbeb90 MD |
415 | * Using fork to set umask in the child process (not multi-thread safe). |
416 | * We deal with the shm_open vs ftruncate race (happening when the | |
417 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
418 | * safety against shm_unlink) by simply letting the mmap fail and | |
419 | * retrying after a few seconds. | |
420 | * For global shm, everybody has rw access to it until the sessiond | |
421 | * starts. | |
58d4b2a2 | 422 | */ |
7fc90dca | 423 | static |
58d4b2a2 | 424 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 425 | { |
7fc90dca | 426 | int wait_shm_fd, ret; |
58d4b2a2 | 427 | pid_t pid; |
44e073f5 | 428 | |
58d4b2a2 | 429 | /* |
33bbeb90 | 430 | * Try to open read-only. |
58d4b2a2 | 431 | */ |
33bbeb90 | 432 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
433 | if (wait_shm_fd >= 0) { |
434 | goto end; | |
435 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
436 | /* | |
33bbeb90 MD |
437 | * Real-only open did not work, and it's not because the |
438 | * entry was not present. It's a failure that prohibits | |
439 | * using shm. | |
58d4b2a2 | 440 | */ |
7fc90dca | 441 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 442 | goto end; |
7fc90dca MD |
443 | } |
444 | /* | |
58d4b2a2 MD |
445 | * If the open failed because the file did not exist, try |
446 | * creating it ourself. | |
7fc90dca | 447 | */ |
58d4b2a2 MD |
448 | pid = fork(); |
449 | if (pid > 0) { | |
450 | int status; | |
451 | ||
452 | /* | |
453 | * Parent: wait for child to return, in which case the | |
454 | * shared memory map will have been created. | |
455 | */ | |
456 | pid = wait(&status); | |
b7d3cb32 | 457 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
458 | wait_shm_fd = -1; |
459 | goto end; | |
7fc90dca | 460 | } |
58d4b2a2 MD |
461 | /* |
462 | * Try to open read-only again after creation. | |
463 | */ | |
33bbeb90 | 464 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
465 | if (wait_shm_fd < 0) { |
466 | /* | |
467 | * Real-only open did not work. It's a failure | |
468 | * that prohibits using shm. | |
469 | */ | |
470 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
471 | goto end; | |
472 | } | |
473 | goto end; | |
474 | } else if (pid == 0) { | |
475 | int create_mode; | |
476 | ||
477 | /* Child */ | |
33bbeb90 | 478 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 479 | if (sock_info->global) |
33bbeb90 | 480 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
481 | /* |
482 | * We're alone in a child process, so we can modify the | |
483 | * process-wide umask. | |
484 | */ | |
33bbeb90 | 485 | umask(~create_mode); |
58d4b2a2 | 486 | /* |
33bbeb90 MD |
487 | * Try creating shm (or get rw access). |
488 | * We don't do an exclusive open, because we allow other | |
489 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
490 | */ |
491 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
492 | O_RDWR | O_CREAT, create_mode); | |
493 | if (wait_shm_fd >= 0) { | |
494 | ret = ftruncate(wait_shm_fd, mmap_size); | |
495 | if (ret) { | |
496 | PERROR("ftruncate"); | |
497 | exit(EXIT_FAILURE); | |
498 | } | |
58d4b2a2 MD |
499 | exit(EXIT_SUCCESS); |
500 | } | |
33bbeb90 MD |
501 | /* |
502 | * For local shm, we need to have rw access to accept | |
503 | * opening it: this means the local sessiond will be | |
504 | * able to wake us up. For global shm, we open it even | |
505 | * if rw access is not granted, because the root.root | |
506 | * sessiond will be able to override all rights and wake | |
507 | * us up. | |
508 | */ | |
509 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
510 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
511 | exit(EXIT_FAILURE); | |
512 | } | |
513 | /* | |
33bbeb90 MD |
514 | * The shm exists, but we cannot open it RW. Report |
515 | * success. | |
58d4b2a2 MD |
516 | */ |
517 | exit(EXIT_SUCCESS); | |
518 | } else { | |
519 | return -1; | |
7fc90dca | 520 | } |
58d4b2a2 | 521 | end: |
33bbeb90 MD |
522 | if (wait_shm_fd >= 0 && !sock_info->global) { |
523 | struct stat statbuf; | |
524 | ||
525 | /* | |
526 | * Ensure that our user is the owner of the shm file for | |
527 | * local shm. If we do not own the file, it means our | |
528 | * sessiond will not have access to wake us up (there is | |
529 | * probably a rogue process trying to fake our | |
530 | * sessiond). Fallback to polling method in this case. | |
531 | */ | |
532 | ret = fstat(wait_shm_fd, &statbuf); | |
533 | if (ret) { | |
534 | PERROR("fstat"); | |
535 | goto error_close; | |
536 | } | |
537 | if (statbuf.st_uid != getuid()) | |
538 | goto error_close; | |
539 | } | |
58d4b2a2 | 540 | return wait_shm_fd; |
33bbeb90 MD |
541 | |
542 | error_close: | |
543 | ret = close(wait_shm_fd); | |
544 | if (ret) { | |
545 | PERROR("Error closing fd"); | |
546 | } | |
547 | return -1; | |
58d4b2a2 MD |
548 | } |
549 | ||
550 | static | |
551 | char *get_map_shm(struct sock_info *sock_info) | |
552 | { | |
553 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
554 | int wait_shm_fd, ret; | |
555 | char *wait_shm_mmap; | |
556 | ||
557 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
558 | if (wait_shm_fd < 0) { | |
559 | goto error; | |
44e073f5 | 560 | } |
7fc90dca MD |
561 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
562 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
563 | /* close shm fd immediately after taking the mmap reference */ |
564 | ret = close(wait_shm_fd); | |
565 | if (ret) { | |
33bbeb90 MD |
566 | PERROR("Error closing fd"); |
567 | } | |
568 | if (wait_shm_mmap == MAP_FAILED) { | |
569 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
570 | goto error; | |
7fc90dca MD |
571 | } |
572 | return wait_shm_mmap; | |
573 | ||
574 | error: | |
575 | return NULL; | |
576 | } | |
577 | ||
578 | static | |
579 | void wait_for_sessiond(struct sock_info *sock_info) | |
580 | { | |
80e2814b MD |
581 | int ret; |
582 | ||
7fc90dca MD |
583 | ust_lock(); |
584 | if (lttng_ust_comm_should_quit) { | |
585 | goto quit; | |
586 | } | |
37ed587a MD |
587 | if (wait_poll_fallback) { |
588 | goto error; | |
589 | } | |
7fc90dca MD |
590 | if (!sock_info->wait_shm_mmap) { |
591 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
592 | if (!sock_info->wait_shm_mmap) | |
593 | goto error; | |
594 | } | |
595 | ust_unlock(); | |
596 | ||
597 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
598 | /* Wait for futex wakeup */ |
599 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
600 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
601 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 602 | if (ret < 0) { |
37ed587a MD |
603 | if (errno == EFAULT) { |
604 | wait_poll_fallback = 1; | |
a8b870ad | 605 | DBG( |
37ed587a MD |
606 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
607 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
608 | "Please upgrade your kernel " | |
609 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
610 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
611 | if (ust_debug()) |
612 | PERROR("futex"); | |
37ed587a | 613 | } |
80e2814b MD |
614 | } |
615 | } | |
7fc90dca MD |
616 | return; |
617 | ||
618 | quit: | |
619 | ust_unlock(); | |
620 | return; | |
621 | ||
622 | error: | |
623 | ust_unlock(); | |
7fc90dca | 624 | return; |
46050b1a MD |
625 | } |
626 | ||
1ea11eab MD |
627 | /* |
628 | * This thread does not allocate any resource, except within | |
629 | * handle_message, within mutex protection. This mutex protects against | |
630 | * fork and exit. | |
631 | * The other moment it allocates resources is at socket connexion, which | |
632 | * is also protected by the mutex. | |
633 | */ | |
d9e99d10 MD |
634 | static |
635 | void *ust_listener_thread(void *arg) | |
636 | { | |
1ea11eab | 637 | struct sock_info *sock_info = arg; |
c0eedf81 | 638 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 639 | |
9eb62b9c MD |
640 | /* Restart trying to connect to the session daemon */ |
641 | restart: | |
c0eedf81 MD |
642 | if (prev_connect_failed) { |
643 | /* Wait for sessiond availability with pipe */ | |
644 | wait_for_sessiond(sock_info); | |
645 | if (has_waited) { | |
646 | has_waited = 0; | |
647 | /* | |
648 | * Sleep for 5 seconds before retrying after a | |
649 | * sequence of failure / wait / failure. This | |
650 | * deals with a killed or broken session daemon. | |
651 | */ | |
652 | sleep(5); | |
653 | } | |
654 | has_waited = 1; | |
655 | prev_connect_failed = 0; | |
656 | } | |
17dfb34b | 657 | ust_lock(); |
1ea11eab MD |
658 | |
659 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 660 | ust_unlock(); |
1ea11eab MD |
661 | goto quit; |
662 | } | |
9eb62b9c | 663 | |
1ea11eab MD |
664 | if (sock_info->socket != -1) { |
665 | ret = close(sock_info->socket); | |
666 | if (ret) { | |
11ff9c7d | 667 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
668 | } |
669 | sock_info->socket = -1; | |
670 | } | |
46050b1a | 671 | |
9eb62b9c | 672 | /* Register */ |
57773204 | 673 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 674 | if (ret < 0) { |
4d3c9523 | 675 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 676 | prev_connect_failed = 1; |
11ff9c7d MD |
677 | /* |
678 | * If we cannot find the sessiond daemon, don't delay | |
679 | * constructor execution. | |
680 | */ | |
edaa1431 | 681 | ret = handle_register_done(sock_info); |
11ff9c7d | 682 | assert(!ret); |
17dfb34b | 683 | ust_unlock(); |
1ea11eab | 684 | goto restart; |
46050b1a MD |
685 | } |
686 | ||
687 | sock_info->socket = sock = ret; | |
688 | ||
689 | /* | |
690 | * Create only one root handle per listener thread for the whole | |
691 | * process lifetime. | |
692 | */ | |
693 | if (sock_info->root_handle == -1) { | |
694 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 695 | if (ret < 0) { |
46050b1a | 696 | ERR("Error creating root handle"); |
17dfb34b | 697 | ust_unlock(); |
46050b1a MD |
698 | goto quit; |
699 | } | |
700 | sock_info->root_handle = ret; | |
9eb62b9c | 701 | } |
1ea11eab | 702 | |
9eb62b9c MD |
703 | ret = register_app_to_sessiond(sock); |
704 | if (ret < 0) { | |
11ff9c7d | 705 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 706 | prev_connect_failed = 1; |
11ff9c7d MD |
707 | /* |
708 | * If we cannot register to the sessiond daemon, don't | |
709 | * delay constructor execution. | |
710 | */ | |
edaa1431 | 711 | ret = handle_register_done(sock_info); |
11ff9c7d | 712 | assert(!ret); |
17dfb34b | 713 | ust_unlock(); |
9eb62b9c MD |
714 | goto restart; |
715 | } | |
17dfb34b | 716 | ust_unlock(); |
46050b1a | 717 | |
d9e99d10 MD |
718 | for (;;) { |
719 | ssize_t len; | |
57773204 | 720 | struct ustcomm_ust_msg lum; |
d9e99d10 | 721 | |
57773204 | 722 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
723 | switch (len) { |
724 | case 0: /* orderly shutdown */ | |
11ff9c7d | 725 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
726 | ust_lock(); |
727 | /* | |
728 | * Either sessiond has shutdown or refused us by closing the socket. | |
729 | * In either case, we don't want to delay construction execution, | |
730 | * and we need to wait before retry. | |
731 | */ | |
732 | prev_connect_failed = 1; | |
733 | /* | |
734 | * If we cannot register to the sessiond daemon, don't | |
735 | * delay constructor execution. | |
736 | */ | |
737 | ret = handle_register_done(sock_info); | |
738 | assert(!ret); | |
739 | ust_unlock(); | |
d9e99d10 | 740 | goto end; |
e7723462 | 741 | case sizeof(lum): |
d9e99d10 | 742 | DBG("message received\n"); |
11ff9c7d | 743 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 744 | if (ret < 0) { |
11ff9c7d | 745 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
746 | } |
747 | continue; | |
748 | case -1: | |
8236ba10 | 749 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 750 | if (errno == ECONNRESET) { |
11ff9c7d | 751 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
752 | goto end; |
753 | } | |
754 | goto end; | |
755 | default: | |
11ff9c7d | 756 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
757 | continue; |
758 | } | |
759 | ||
760 | } | |
761 | end: | |
9eb62b9c | 762 | goto restart; /* try to reconnect */ |
1ea11eab | 763 | quit: |
d9e99d10 MD |
764 | return NULL; |
765 | } | |
766 | ||
cf12a773 MD |
767 | /* |
768 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
769 | */ | |
11ff9c7d MD |
770 | static |
771 | int get_timeout(struct timespec *constructor_timeout) | |
772 | { | |
cf12a773 MD |
773 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
774 | char *str_delay; | |
11ff9c7d MD |
775 | int ret; |
776 | ||
69400ac4 | 777 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
778 | if (str_delay) { |
779 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
780 | } | |
781 | ||
782 | switch (constructor_delay_ms) { | |
783 | case -1:/* fall-through */ | |
784 | case 0: | |
785 | return constructor_delay_ms; | |
786 | default: | |
787 | break; | |
788 | } | |
789 | ||
790 | /* | |
791 | * If we are unable to find the current time, don't wait. | |
792 | */ | |
793 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
794 | if (ret) { | |
795 | return -1; | |
796 | } | |
95259bd0 MD |
797 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
798 | constructor_timeout->tv_nsec += | |
799 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
800 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
801 | constructor_timeout->tv_sec++; | |
802 | constructor_timeout->tv_nsec -= 1000000000UL; | |
803 | } | |
cf12a773 | 804 | return 1; |
11ff9c7d | 805 | } |
d9e99d10 | 806 | |
2691221a MD |
807 | /* |
808 | * sessiond monitoring thread: monitor presence of global and per-user | |
809 | * sessiond by polling the application common named pipe. | |
810 | */ | |
811 | /* TODO */ | |
812 | ||
edaa1431 | 813 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 814 | { |
11ff9c7d | 815 | struct timespec constructor_timeout; |
cf12a773 | 816 | int timeout_mode; |
2691221a MD |
817 | int ret; |
818 | ||
edaa1431 MD |
819 | if (uatomic_xchg(&initialized, 1) == 1) |
820 | return; | |
821 | ||
822 | /* | |
823 | * We want precise control over the order in which we construct | |
824 | * our sub-libraries vs starting to receive commands from | |
825 | * sessiond (otherwise leading to errors when trying to create | |
826 | * sessiond before the init functions are completed). | |
827 | */ | |
2691221a | 828 | init_usterr(); |
edaa1431 MD |
829 | init_tracepoint(); |
830 | ltt_ring_buffer_metadata_client_init(); | |
831 | ltt_ring_buffer_client_overwrite_init(); | |
832 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 833 | |
cf12a773 | 834 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 835 | |
95259bd0 | 836 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
837 | assert(!ret); |
838 | ||
8d20bf54 | 839 | ret = setup_local_apps(); |
2691221a | 840 | if (ret) { |
8d20bf54 | 841 | ERR("Error setting up to local apps"); |
2691221a | 842 | } |
1ea11eab MD |
843 | ret = pthread_create(&local_apps.ust_listener, NULL, |
844 | ust_listener_thread, &local_apps); | |
11ff9c7d | 845 | |
8d20bf54 MD |
846 | if (local_apps.allowed) { |
847 | ret = pthread_create(&global_apps.ust_listener, NULL, | |
848 | ust_listener_thread, &global_apps); | |
849 | } else { | |
850 | handle_register_done(&local_apps); | |
851 | } | |
852 | ||
cf12a773 MD |
853 | switch (timeout_mode) { |
854 | case 1: /* timeout wait */ | |
95259bd0 MD |
855 | do { |
856 | ret = sem_timedwait(&constructor_wait, | |
857 | &constructor_timeout); | |
858 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
859 | if (ret < 0 && errno == ETIMEDOUT) { |
860 | ERR("Timed out waiting for ltt-sessiond"); | |
861 | } else { | |
862 | assert(!ret); | |
863 | } | |
864 | break; | |
7b766b16 | 865 | case -1:/* wait forever */ |
95259bd0 MD |
866 | do { |
867 | ret = sem_wait(&constructor_wait); | |
868 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 869 | assert(!ret); |
cf12a773 | 870 | break; |
7b766b16 | 871 | case 0: /* no timeout */ |
cf12a773 | 872 | break; |
11ff9c7d | 873 | } |
2691221a MD |
874 | } |
875 | ||
17dfb34b MD |
876 | static |
877 | void lttng_ust_cleanup(int exiting) | |
878 | { | |
879 | cleanup_sock_info(&global_apps); | |
880 | if (local_apps.allowed) { | |
881 | cleanup_sock_info(&local_apps); | |
882 | } | |
883 | lttng_ust_abi_exit(); | |
003fedf4 | 884 | lttng_ust_events_exit(); |
17dfb34b MD |
885 | ltt_ring_buffer_client_discard_exit(); |
886 | ltt_ring_buffer_client_overwrite_exit(); | |
887 | ltt_ring_buffer_metadata_client_exit(); | |
888 | exit_tracepoint(); | |
889 | if (!exiting) { | |
890 | /* Reinitialize values for fork */ | |
891 | sem_count = 2; | |
892 | lttng_ust_comm_should_quit = 0; | |
893 | initialized = 0; | |
894 | } | |
895 | } | |
896 | ||
edaa1431 | 897 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
898 | { |
899 | int ret; | |
900 | ||
9eb62b9c MD |
901 | /* |
902 | * Using pthread_cancel here because: | |
903 | * A) we don't want to hang application teardown. | |
904 | * B) the thread is not allocating any resource. | |
905 | */ | |
1ea11eab MD |
906 | |
907 | /* | |
908 | * Require the communication thread to quit. Synchronize with | |
909 | * mutexes to ensure it is not in a mutex critical section when | |
910 | * pthread_cancel is later called. | |
911 | */ | |
17dfb34b | 912 | ust_lock(); |
1ea11eab | 913 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 914 | ust_unlock(); |
1ea11eab | 915 | |
1ea11eab | 916 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c MD |
917 | if (ret) { |
918 | ERR("Error cancelling global ust listener thread"); | |
2691221a | 919 | } |
8d20bf54 MD |
920 | if (local_apps.allowed) { |
921 | ret = pthread_cancel(local_apps.ust_listener); | |
922 | if (ret) { | |
923 | ERR("Error cancelling local ust listener thread"); | |
924 | } | |
8d20bf54 | 925 | } |
17dfb34b | 926 | lttng_ust_cleanup(1); |
2691221a | 927 | } |
e822f505 MD |
928 | |
929 | /* | |
930 | * We exclude the worker threads across fork and clone (except | |
931 | * CLONE_VM), because these system calls only keep the forking thread | |
932 | * running in the child. Therefore, we don't want to call fork or clone | |
933 | * in the middle of an tracepoint or ust tracing state modification. | |
934 | * Holding this mutex protects these structures across fork and clone. | |
935 | */ | |
b728d87e | 936 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
937 | { |
938 | /* | |
939 | * Disable signals. This is to avoid that the child intervenes | |
940 | * before it is properly setup for tracing. It is safer to | |
941 | * disable all signals, because then we know we are not breaking | |
942 | * anything by restoring the original mask. | |
943 | */ | |
944 | sigset_t all_sigs; | |
945 | int ret; | |
946 | ||
947 | /* Disable signals */ | |
948 | sigfillset(&all_sigs); | |
b728d87e | 949 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
950 | if (ret == -1) { |
951 | PERROR("sigprocmask"); | |
952 | } | |
17dfb34b | 953 | ust_lock(); |
e822f505 MD |
954 | rcu_bp_before_fork(); |
955 | } | |
956 | ||
b728d87e | 957 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
958 | { |
959 | int ret; | |
960 | ||
17dfb34b MD |
961 | DBG("process %d", getpid()); |
962 | ust_unlock(); | |
e822f505 | 963 | /* Restore signals */ |
23c8854a | 964 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
965 | if (ret == -1) { |
966 | PERROR("sigprocmask"); | |
967 | } | |
968 | } | |
969 | ||
b728d87e | 970 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 971 | { |
17dfb34b | 972 | DBG("process %d", getpid()); |
e822f505 MD |
973 | rcu_bp_after_fork_parent(); |
974 | /* Release mutexes and reenable signals */ | |
b728d87e | 975 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
976 | } |
977 | ||
17dfb34b MD |
978 | /* |
979 | * After fork, in the child, we need to cleanup all the leftover state, | |
980 | * except the worker thread which already magically disappeared thanks | |
981 | * to the weird Linux fork semantics. After tyding up, we call | |
982 | * lttng_ust_init() again to start over as a new PID. | |
983 | * | |
984 | * This is meant for forks() that have tracing in the child between the | |
985 | * fork and following exec call (if there is any). | |
986 | */ | |
b728d87e | 987 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 988 | { |
17dfb34b | 989 | DBG("process %d", getpid()); |
e822f505 MD |
990 | /* Release urcu mutexes */ |
991 | rcu_bp_after_fork_child(); | |
17dfb34b | 992 | lttng_ust_cleanup(0); |
a93bfc45 | 993 | lttng_context_vtid_reset(); |
e822f505 | 994 | /* Release mutexes and reenable signals */ |
b728d87e | 995 | ust_after_fork_common(restore_sigset); |
318dfea9 | 996 | lttng_ust_init(); |
e822f505 | 997 | } |