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; |
ef9ff354 | 242 | union ust_args args; |
1ea11eab | 243 | |
17dfb34b | 244 | ust_lock(); |
1ea11eab | 245 | |
46050b1a MD |
246 | memset(&lur, 0, sizeof(lur)); |
247 | ||
1ea11eab | 248 | if (lttng_ust_comm_should_quit) { |
46050b1a | 249 | ret = -EPERM; |
1ea11eab MD |
250 | goto end; |
251 | } | |
9eb62b9c | 252 | |
46050b1a MD |
253 | ops = objd_ops(lum->handle); |
254 | if (!ops) { | |
255 | ret = -ENOENT; | |
256 | goto end; | |
1ea11eab | 257 | } |
46050b1a MD |
258 | |
259 | switch (lum->cmd) { | |
11ff9c7d MD |
260 | case LTTNG_UST_REGISTER_DONE: |
261 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 262 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
263 | else |
264 | ret = -EINVAL; | |
265 | break; | |
46050b1a MD |
266 | case LTTNG_UST_RELEASE: |
267 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
268 | ret = -EPERM; | |
269 | else | |
d4419b81 | 270 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 MD |
271 | break; |
272 | default: | |
46050b1a MD |
273 | if (ops->cmd) |
274 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
275 | (unsigned long) &lum->u, |
276 | &args); | |
46050b1a MD |
277 | else |
278 | ret = -ENOSYS; | |
279 | break; | |
d9e99d10 | 280 | } |
46050b1a | 281 | |
1ea11eab | 282 | end: |
46050b1a MD |
283 | lur.handle = lum->handle; |
284 | lur.cmd = lum->cmd; | |
285 | lur.ret_val = ret; | |
286 | if (ret >= 0) { | |
57773204 | 287 | lur.ret_code = USTCOMM_OK; |
46050b1a | 288 | } else { |
57773204 | 289 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 290 | lur.ret_code = ret; |
46050b1a | 291 | } |
193183fb MD |
292 | switch (lum->cmd) { |
293 | case LTTNG_UST_STREAM: | |
381c0f1e MD |
294 | /* |
295 | * Special-case reply to send stream info. | |
296 | * Use lum.u output. | |
297 | */ | |
ef9ff354 MD |
298 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; |
299 | shm_fd = *args.stream.shm_fd; | |
300 | wait_fd = *args.stream.wait_fd; | |
193183fb | 301 | break; |
824f40b8 | 302 | case LTTNG_UST_METADATA: |
193183fb | 303 | case LTTNG_UST_CHANNEL: |
ef9ff354 MD |
304 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; |
305 | shm_fd = *args.channel.shm_fd; | |
306 | wait_fd = *args.channel.wait_fd; | |
193183fb | 307 | break; |
23c8854a | 308 | case LTTNG_UST_TRACER_VERSION: |
57773204 MD |
309 | lur.u.version = lum->u.version; |
310 | break; | |
b115631f | 311 | case LTTNG_UST_TRACEPOINT_LIST_GET: |
cbef6901 | 312 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); |
b115631f | 313 | break; |
381c0f1e | 314 | } |
46050b1a | 315 | ret = send_reply(sock, &lur); |
193183fb MD |
316 | if (ret < 0) { |
317 | perror("error sending reply"); | |
318 | goto error; | |
319 | } | |
46050b1a | 320 | |
824f40b8 MD |
321 | if ((lum->cmd == LTTNG_UST_STREAM |
322 | || lum->cmd == LTTNG_UST_CHANNEL | |
323 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 324 | && lur.ret_code == USTCOMM_OK) { |
381c0f1e | 325 | /* we also need to send the file descriptors. */ |
57773204 | 326 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 327 | &shm_fd, &shm_fd, |
381c0f1e MD |
328 | 1, sizeof(int)); |
329 | if (ret < 0) { | |
330 | perror("send shm_fd"); | |
331 | goto error; | |
332 | } | |
57773204 | 333 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 334 | &wait_fd, &wait_fd, |
381c0f1e MD |
335 | 1, sizeof(int)); |
336 | if (ret < 0) { | |
337 | perror("send wait_fd"); | |
338 | goto error; | |
339 | } | |
340 | } | |
ef9ff354 MD |
341 | /* |
342 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
343 | * sent to the sessiond. We can therefore close those fds. Note |
344 | * that we keep the write side of the wait_fd open, but close | |
345 | * the read side. | |
ef9ff354 MD |
346 | */ |
347 | if (lur.ret_code == USTCOMM_OK) { | |
348 | switch (lum->cmd) { | |
349 | case LTTNG_UST_STREAM: | |
350 | if (shm_fd >= 0) { | |
351 | ret = close(shm_fd); | |
352 | if (ret) { | |
353 | PERROR("Error closing stream shm_fd"); | |
354 | } | |
355 | *args.stream.shm_fd = -1; | |
356 | } | |
357 | if (wait_fd >= 0) { | |
358 | ret = close(wait_fd); | |
359 | if (ret) { | |
360 | PERROR("Error closing stream wait_fd"); | |
361 | } | |
362 | *args.stream.wait_fd = -1; | |
363 | } | |
364 | break; | |
365 | case LTTNG_UST_METADATA: | |
366 | case LTTNG_UST_CHANNEL: | |
367 | if (shm_fd >= 0) { | |
368 | ret = close(shm_fd); | |
369 | if (ret) { | |
370 | PERROR("Error closing channel shm_fd"); | |
371 | } | |
372 | *args.channel.shm_fd = -1; | |
373 | } | |
374 | if (wait_fd >= 0) { | |
375 | ret = close(wait_fd); | |
376 | if (ret) { | |
377 | PERROR("Error closing channel wait_fd"); | |
378 | } | |
379 | *args.channel.wait_fd = -1; | |
380 | } | |
381 | break; | |
382 | } | |
383 | } | |
384 | ||
381c0f1e | 385 | error: |
17dfb34b | 386 | ust_unlock(); |
1ea11eab | 387 | return ret; |
d9e99d10 MD |
388 | } |
389 | ||
46050b1a MD |
390 | static |
391 | void cleanup_sock_info(struct sock_info *sock_info) | |
392 | { | |
393 | int ret; | |
394 | ||
395 | if (sock_info->socket != -1) { | |
396 | ret = close(sock_info->socket); | |
397 | if (ret) { | |
7fc90dca | 398 | ERR("Error closing apps socket"); |
46050b1a MD |
399 | } |
400 | sock_info->socket = -1; | |
401 | } | |
402 | if (sock_info->root_handle != -1) { | |
d4419b81 | 403 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
404 | if (ret) { |
405 | ERR("Error unref root handle"); | |
406 | } | |
407 | sock_info->root_handle = -1; | |
408 | } | |
318dfea9 | 409 | sock_info->constructor_sem_posted = 0; |
7fc90dca MD |
410 | if (sock_info->wait_shm_mmap) { |
411 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); | |
412 | if (ret) { | |
413 | ERR("Error unmapping wait shm"); | |
414 | } | |
415 | sock_info->wait_shm_mmap = NULL; | |
416 | } | |
417 | } | |
418 | ||
58d4b2a2 | 419 | /* |
33bbeb90 MD |
420 | * Using fork to set umask in the child process (not multi-thread safe). |
421 | * We deal with the shm_open vs ftruncate race (happening when the | |
422 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
423 | * safety against shm_unlink) by simply letting the mmap fail and | |
424 | * retrying after a few seconds. | |
425 | * For global shm, everybody has rw access to it until the sessiond | |
426 | * starts. | |
58d4b2a2 | 427 | */ |
7fc90dca | 428 | static |
58d4b2a2 | 429 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 430 | { |
7fc90dca | 431 | int wait_shm_fd, ret; |
58d4b2a2 | 432 | pid_t pid; |
44e073f5 | 433 | |
58d4b2a2 | 434 | /* |
33bbeb90 | 435 | * Try to open read-only. |
58d4b2a2 | 436 | */ |
33bbeb90 | 437 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
438 | if (wait_shm_fd >= 0) { |
439 | goto end; | |
440 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
441 | /* | |
33bbeb90 MD |
442 | * Real-only open did not work, and it's not because the |
443 | * entry was not present. It's a failure that prohibits | |
444 | * using shm. | |
58d4b2a2 | 445 | */ |
7fc90dca | 446 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 447 | goto end; |
7fc90dca MD |
448 | } |
449 | /* | |
58d4b2a2 MD |
450 | * If the open failed because the file did not exist, try |
451 | * creating it ourself. | |
7fc90dca | 452 | */ |
58d4b2a2 MD |
453 | pid = fork(); |
454 | if (pid > 0) { | |
455 | int status; | |
456 | ||
457 | /* | |
458 | * Parent: wait for child to return, in which case the | |
459 | * shared memory map will have been created. | |
460 | */ | |
461 | pid = wait(&status); | |
b7d3cb32 | 462 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
463 | wait_shm_fd = -1; |
464 | goto end; | |
7fc90dca | 465 | } |
58d4b2a2 MD |
466 | /* |
467 | * Try to open read-only again after creation. | |
468 | */ | |
33bbeb90 | 469 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
470 | if (wait_shm_fd < 0) { |
471 | /* | |
472 | * Real-only open did not work. It's a failure | |
473 | * that prohibits using shm. | |
474 | */ | |
475 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
476 | goto end; | |
477 | } | |
478 | goto end; | |
479 | } else if (pid == 0) { | |
480 | int create_mode; | |
481 | ||
482 | /* Child */ | |
33bbeb90 | 483 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 484 | if (sock_info->global) |
33bbeb90 | 485 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
486 | /* |
487 | * We're alone in a child process, so we can modify the | |
488 | * process-wide umask. | |
489 | */ | |
33bbeb90 | 490 | umask(~create_mode); |
58d4b2a2 | 491 | /* |
33bbeb90 MD |
492 | * Try creating shm (or get rw access). |
493 | * We don't do an exclusive open, because we allow other | |
494 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
495 | */ |
496 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
497 | O_RDWR | O_CREAT, create_mode); | |
498 | if (wait_shm_fd >= 0) { | |
499 | ret = ftruncate(wait_shm_fd, mmap_size); | |
500 | if (ret) { | |
501 | PERROR("ftruncate"); | |
502 | exit(EXIT_FAILURE); | |
503 | } | |
58d4b2a2 MD |
504 | exit(EXIT_SUCCESS); |
505 | } | |
33bbeb90 MD |
506 | /* |
507 | * For local shm, we need to have rw access to accept | |
508 | * opening it: this means the local sessiond will be | |
509 | * able to wake us up. For global shm, we open it even | |
510 | * if rw access is not granted, because the root.root | |
511 | * sessiond will be able to override all rights and wake | |
512 | * us up. | |
513 | */ | |
514 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
515 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
516 | exit(EXIT_FAILURE); | |
517 | } | |
518 | /* | |
33bbeb90 MD |
519 | * The shm exists, but we cannot open it RW. Report |
520 | * success. | |
58d4b2a2 MD |
521 | */ |
522 | exit(EXIT_SUCCESS); | |
523 | } else { | |
524 | return -1; | |
7fc90dca | 525 | } |
58d4b2a2 | 526 | end: |
33bbeb90 MD |
527 | if (wait_shm_fd >= 0 && !sock_info->global) { |
528 | struct stat statbuf; | |
529 | ||
530 | /* | |
531 | * Ensure that our user is the owner of the shm file for | |
532 | * local shm. If we do not own the file, it means our | |
533 | * sessiond will not have access to wake us up (there is | |
534 | * probably a rogue process trying to fake our | |
535 | * sessiond). Fallback to polling method in this case. | |
536 | */ | |
537 | ret = fstat(wait_shm_fd, &statbuf); | |
538 | if (ret) { | |
539 | PERROR("fstat"); | |
540 | goto error_close; | |
541 | } | |
542 | if (statbuf.st_uid != getuid()) | |
543 | goto error_close; | |
544 | } | |
58d4b2a2 | 545 | return wait_shm_fd; |
33bbeb90 MD |
546 | |
547 | error_close: | |
548 | ret = close(wait_shm_fd); | |
549 | if (ret) { | |
550 | PERROR("Error closing fd"); | |
551 | } | |
552 | return -1; | |
58d4b2a2 MD |
553 | } |
554 | ||
555 | static | |
556 | char *get_map_shm(struct sock_info *sock_info) | |
557 | { | |
558 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
559 | int wait_shm_fd, ret; | |
560 | char *wait_shm_mmap; | |
561 | ||
562 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
563 | if (wait_shm_fd < 0) { | |
564 | goto error; | |
44e073f5 | 565 | } |
7fc90dca MD |
566 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
567 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
568 | /* close shm fd immediately after taking the mmap reference */ |
569 | ret = close(wait_shm_fd); | |
570 | if (ret) { | |
33bbeb90 MD |
571 | PERROR("Error closing fd"); |
572 | } | |
573 | if (wait_shm_mmap == MAP_FAILED) { | |
574 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
575 | goto error; | |
7fc90dca MD |
576 | } |
577 | return wait_shm_mmap; | |
578 | ||
579 | error: | |
580 | return NULL; | |
581 | } | |
582 | ||
583 | static | |
584 | void wait_for_sessiond(struct sock_info *sock_info) | |
585 | { | |
80e2814b MD |
586 | int ret; |
587 | ||
7fc90dca MD |
588 | ust_lock(); |
589 | if (lttng_ust_comm_should_quit) { | |
590 | goto quit; | |
591 | } | |
37ed587a MD |
592 | if (wait_poll_fallback) { |
593 | goto error; | |
594 | } | |
7fc90dca MD |
595 | if (!sock_info->wait_shm_mmap) { |
596 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
597 | if (!sock_info->wait_shm_mmap) | |
598 | goto error; | |
599 | } | |
600 | ust_unlock(); | |
601 | ||
602 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
603 | /* Wait for futex wakeup */ |
604 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
605 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
606 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 607 | if (ret < 0) { |
37ed587a MD |
608 | if (errno == EFAULT) { |
609 | wait_poll_fallback = 1; | |
a8b870ad | 610 | DBG( |
37ed587a MD |
611 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
612 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
613 | "Please upgrade your kernel " | |
614 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
615 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
616 | if (ust_debug()) |
617 | PERROR("futex"); | |
37ed587a | 618 | } |
80e2814b MD |
619 | } |
620 | } | |
7fc90dca MD |
621 | return; |
622 | ||
623 | quit: | |
624 | ust_unlock(); | |
625 | return; | |
626 | ||
627 | error: | |
628 | ust_unlock(); | |
7fc90dca | 629 | return; |
46050b1a MD |
630 | } |
631 | ||
1ea11eab MD |
632 | /* |
633 | * This thread does not allocate any resource, except within | |
634 | * handle_message, within mutex protection. This mutex protects against | |
635 | * fork and exit. | |
636 | * The other moment it allocates resources is at socket connexion, which | |
637 | * is also protected by the mutex. | |
638 | */ | |
d9e99d10 MD |
639 | static |
640 | void *ust_listener_thread(void *arg) | |
641 | { | |
1ea11eab | 642 | struct sock_info *sock_info = arg; |
c0eedf81 | 643 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 644 | |
9eb62b9c MD |
645 | /* Restart trying to connect to the session daemon */ |
646 | restart: | |
c0eedf81 MD |
647 | if (prev_connect_failed) { |
648 | /* Wait for sessiond availability with pipe */ | |
649 | wait_for_sessiond(sock_info); | |
650 | if (has_waited) { | |
651 | has_waited = 0; | |
652 | /* | |
653 | * Sleep for 5 seconds before retrying after a | |
654 | * sequence of failure / wait / failure. This | |
655 | * deals with a killed or broken session daemon. | |
656 | */ | |
657 | sleep(5); | |
658 | } | |
659 | has_waited = 1; | |
660 | prev_connect_failed = 0; | |
661 | } | |
17dfb34b | 662 | ust_lock(); |
1ea11eab MD |
663 | |
664 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 665 | ust_unlock(); |
1ea11eab MD |
666 | goto quit; |
667 | } | |
9eb62b9c | 668 | |
1ea11eab MD |
669 | if (sock_info->socket != -1) { |
670 | ret = close(sock_info->socket); | |
671 | if (ret) { | |
11ff9c7d | 672 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
673 | } |
674 | sock_info->socket = -1; | |
675 | } | |
46050b1a | 676 | |
9eb62b9c | 677 | /* Register */ |
57773204 | 678 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 679 | if (ret < 0) { |
4d3c9523 | 680 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 681 | prev_connect_failed = 1; |
11ff9c7d MD |
682 | /* |
683 | * If we cannot find the sessiond daemon, don't delay | |
684 | * constructor execution. | |
685 | */ | |
edaa1431 | 686 | ret = handle_register_done(sock_info); |
11ff9c7d | 687 | assert(!ret); |
17dfb34b | 688 | ust_unlock(); |
1ea11eab | 689 | goto restart; |
46050b1a MD |
690 | } |
691 | ||
692 | sock_info->socket = sock = ret; | |
693 | ||
694 | /* | |
695 | * Create only one root handle per listener thread for the whole | |
696 | * process lifetime. | |
697 | */ | |
698 | if (sock_info->root_handle == -1) { | |
699 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 700 | if (ret < 0) { |
46050b1a | 701 | ERR("Error creating root handle"); |
17dfb34b | 702 | ust_unlock(); |
46050b1a MD |
703 | goto quit; |
704 | } | |
705 | sock_info->root_handle = ret; | |
9eb62b9c | 706 | } |
1ea11eab | 707 | |
9eb62b9c MD |
708 | ret = register_app_to_sessiond(sock); |
709 | if (ret < 0) { | |
11ff9c7d | 710 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 711 | prev_connect_failed = 1; |
11ff9c7d MD |
712 | /* |
713 | * If we cannot register to the sessiond daemon, don't | |
714 | * delay constructor execution. | |
715 | */ | |
edaa1431 | 716 | ret = handle_register_done(sock_info); |
11ff9c7d | 717 | assert(!ret); |
17dfb34b | 718 | ust_unlock(); |
9eb62b9c MD |
719 | goto restart; |
720 | } | |
17dfb34b | 721 | ust_unlock(); |
46050b1a | 722 | |
d9e99d10 MD |
723 | for (;;) { |
724 | ssize_t len; | |
57773204 | 725 | struct ustcomm_ust_msg lum; |
d9e99d10 | 726 | |
57773204 | 727 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
728 | switch (len) { |
729 | case 0: /* orderly shutdown */ | |
11ff9c7d | 730 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
731 | ust_lock(); |
732 | /* | |
733 | * Either sessiond has shutdown or refused us by closing the socket. | |
734 | * In either case, we don't want to delay construction execution, | |
735 | * and we need to wait before retry. | |
736 | */ | |
737 | prev_connect_failed = 1; | |
738 | /* | |
739 | * If we cannot register to the sessiond daemon, don't | |
740 | * delay constructor execution. | |
741 | */ | |
742 | ret = handle_register_done(sock_info); | |
743 | assert(!ret); | |
744 | ust_unlock(); | |
d9e99d10 | 745 | goto end; |
e7723462 | 746 | case sizeof(lum): |
d9e99d10 | 747 | DBG("message received\n"); |
11ff9c7d | 748 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 749 | if (ret < 0) { |
11ff9c7d | 750 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
751 | } |
752 | continue; | |
753 | case -1: | |
8236ba10 | 754 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 755 | if (errno == ECONNRESET) { |
11ff9c7d | 756 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
757 | goto end; |
758 | } | |
759 | goto end; | |
760 | default: | |
11ff9c7d | 761 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
762 | continue; |
763 | } | |
764 | ||
765 | } | |
766 | end: | |
9eb62b9c | 767 | goto restart; /* try to reconnect */ |
1ea11eab | 768 | quit: |
d9e99d10 MD |
769 | return NULL; |
770 | } | |
771 | ||
cf12a773 MD |
772 | /* |
773 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
774 | */ | |
11ff9c7d MD |
775 | static |
776 | int get_timeout(struct timespec *constructor_timeout) | |
777 | { | |
cf12a773 MD |
778 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
779 | char *str_delay; | |
11ff9c7d MD |
780 | int ret; |
781 | ||
69400ac4 | 782 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
783 | if (str_delay) { |
784 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
785 | } | |
786 | ||
787 | switch (constructor_delay_ms) { | |
788 | case -1:/* fall-through */ | |
789 | case 0: | |
790 | return constructor_delay_ms; | |
791 | default: | |
792 | break; | |
793 | } | |
794 | ||
795 | /* | |
796 | * If we are unable to find the current time, don't wait. | |
797 | */ | |
798 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
799 | if (ret) { | |
800 | return -1; | |
801 | } | |
95259bd0 MD |
802 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
803 | constructor_timeout->tv_nsec += | |
804 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
805 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
806 | constructor_timeout->tv_sec++; | |
807 | constructor_timeout->tv_nsec -= 1000000000UL; | |
808 | } | |
cf12a773 | 809 | return 1; |
11ff9c7d | 810 | } |
d9e99d10 | 811 | |
2691221a MD |
812 | /* |
813 | * sessiond monitoring thread: monitor presence of global and per-user | |
814 | * sessiond by polling the application common named pipe. | |
815 | */ | |
816 | /* TODO */ | |
817 | ||
edaa1431 | 818 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 819 | { |
11ff9c7d | 820 | struct timespec constructor_timeout; |
cf12a773 | 821 | int timeout_mode; |
2691221a MD |
822 | int ret; |
823 | ||
edaa1431 MD |
824 | if (uatomic_xchg(&initialized, 1) == 1) |
825 | return; | |
826 | ||
827 | /* | |
828 | * We want precise control over the order in which we construct | |
829 | * our sub-libraries vs starting to receive commands from | |
830 | * sessiond (otherwise leading to errors when trying to create | |
831 | * sessiond before the init functions are completed). | |
832 | */ | |
2691221a | 833 | init_usterr(); |
edaa1431 MD |
834 | init_tracepoint(); |
835 | ltt_ring_buffer_metadata_client_init(); | |
836 | ltt_ring_buffer_client_overwrite_init(); | |
837 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 838 | |
cf12a773 | 839 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 840 | |
95259bd0 | 841 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
842 | assert(!ret); |
843 | ||
8d20bf54 | 844 | ret = setup_local_apps(); |
2691221a | 845 | if (ret) { |
8d20bf54 | 846 | ERR("Error setting up to local apps"); |
2691221a | 847 | } |
1ea11eab MD |
848 | ret = pthread_create(&local_apps.ust_listener, NULL, |
849 | ust_listener_thread, &local_apps); | |
11ff9c7d | 850 | |
8d20bf54 MD |
851 | if (local_apps.allowed) { |
852 | ret = pthread_create(&global_apps.ust_listener, NULL, | |
853 | ust_listener_thread, &global_apps); | |
854 | } else { | |
855 | handle_register_done(&local_apps); | |
856 | } | |
857 | ||
cf12a773 MD |
858 | switch (timeout_mode) { |
859 | case 1: /* timeout wait */ | |
95259bd0 MD |
860 | do { |
861 | ret = sem_timedwait(&constructor_wait, | |
862 | &constructor_timeout); | |
863 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
864 | if (ret < 0 && errno == ETIMEDOUT) { |
865 | ERR("Timed out waiting for ltt-sessiond"); | |
866 | } else { | |
867 | assert(!ret); | |
868 | } | |
869 | break; | |
7b766b16 | 870 | case -1:/* wait forever */ |
95259bd0 MD |
871 | do { |
872 | ret = sem_wait(&constructor_wait); | |
873 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 874 | assert(!ret); |
cf12a773 | 875 | break; |
7b766b16 | 876 | case 0: /* no timeout */ |
cf12a773 | 877 | break; |
11ff9c7d | 878 | } |
2691221a MD |
879 | } |
880 | ||
17dfb34b MD |
881 | static |
882 | void lttng_ust_cleanup(int exiting) | |
883 | { | |
884 | cleanup_sock_info(&global_apps); | |
885 | if (local_apps.allowed) { | |
886 | cleanup_sock_info(&local_apps); | |
887 | } | |
888 | lttng_ust_abi_exit(); | |
003fedf4 | 889 | lttng_ust_events_exit(); |
17dfb34b MD |
890 | ltt_ring_buffer_client_discard_exit(); |
891 | ltt_ring_buffer_client_overwrite_exit(); | |
892 | ltt_ring_buffer_metadata_client_exit(); | |
893 | exit_tracepoint(); | |
894 | if (!exiting) { | |
895 | /* Reinitialize values for fork */ | |
896 | sem_count = 2; | |
897 | lttng_ust_comm_should_quit = 0; | |
898 | initialized = 0; | |
899 | } | |
900 | } | |
901 | ||
edaa1431 | 902 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
903 | { |
904 | int ret; | |
905 | ||
9eb62b9c MD |
906 | /* |
907 | * Using pthread_cancel here because: | |
908 | * A) we don't want to hang application teardown. | |
909 | * B) the thread is not allocating any resource. | |
910 | */ | |
1ea11eab MD |
911 | |
912 | /* | |
913 | * Require the communication thread to quit. Synchronize with | |
914 | * mutexes to ensure it is not in a mutex critical section when | |
915 | * pthread_cancel is later called. | |
916 | */ | |
17dfb34b | 917 | ust_lock(); |
1ea11eab | 918 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 919 | ust_unlock(); |
1ea11eab | 920 | |
1ea11eab | 921 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c MD |
922 | if (ret) { |
923 | ERR("Error cancelling global ust listener thread"); | |
2691221a | 924 | } |
8d20bf54 MD |
925 | if (local_apps.allowed) { |
926 | ret = pthread_cancel(local_apps.ust_listener); | |
927 | if (ret) { | |
928 | ERR("Error cancelling local ust listener thread"); | |
929 | } | |
8d20bf54 | 930 | } |
17dfb34b | 931 | lttng_ust_cleanup(1); |
2691221a | 932 | } |
e822f505 MD |
933 | |
934 | /* | |
935 | * We exclude the worker threads across fork and clone (except | |
936 | * CLONE_VM), because these system calls only keep the forking thread | |
937 | * running in the child. Therefore, we don't want to call fork or clone | |
938 | * in the middle of an tracepoint or ust tracing state modification. | |
939 | * Holding this mutex protects these structures across fork and clone. | |
940 | */ | |
b728d87e | 941 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
942 | { |
943 | /* | |
944 | * Disable signals. This is to avoid that the child intervenes | |
945 | * before it is properly setup for tracing. It is safer to | |
946 | * disable all signals, because then we know we are not breaking | |
947 | * anything by restoring the original mask. | |
948 | */ | |
949 | sigset_t all_sigs; | |
950 | int ret; | |
951 | ||
952 | /* Disable signals */ | |
953 | sigfillset(&all_sigs); | |
b728d87e | 954 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
955 | if (ret == -1) { |
956 | PERROR("sigprocmask"); | |
957 | } | |
17dfb34b | 958 | ust_lock(); |
e822f505 MD |
959 | rcu_bp_before_fork(); |
960 | } | |
961 | ||
b728d87e | 962 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
963 | { |
964 | int ret; | |
965 | ||
17dfb34b MD |
966 | DBG("process %d", getpid()); |
967 | ust_unlock(); | |
e822f505 | 968 | /* Restore signals */ |
23c8854a | 969 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
970 | if (ret == -1) { |
971 | PERROR("sigprocmask"); | |
972 | } | |
973 | } | |
974 | ||
b728d87e | 975 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 976 | { |
17dfb34b | 977 | DBG("process %d", getpid()); |
e822f505 MD |
978 | rcu_bp_after_fork_parent(); |
979 | /* Release mutexes and reenable signals */ | |
b728d87e | 980 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
981 | } |
982 | ||
17dfb34b MD |
983 | /* |
984 | * After fork, in the child, we need to cleanup all the leftover state, | |
985 | * except the worker thread which already magically disappeared thanks | |
986 | * to the weird Linux fork semantics. After tyding up, we call | |
987 | * lttng_ust_init() again to start over as a new PID. | |
988 | * | |
989 | * This is meant for forks() that have tracing in the child between the | |
990 | * fork and following exec call (if there is any). | |
991 | */ | |
b728d87e | 992 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 993 | { |
17dfb34b | 994 | DBG("process %d", getpid()); |
e822f505 MD |
995 | /* Release urcu mutexes */ |
996 | rcu_bp_after_fork_child(); | |
17dfb34b | 997 | lttng_ust_cleanup(0); |
a93bfc45 | 998 | lttng_context_vtid_reset(); |
e822f505 | 999 | /* Release mutexes and reenable signals */ |
b728d87e | 1000 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1001 | lttng_ust_init(); |
e822f505 | 1002 | } |