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" |
08114193 | 48 | #include "compat.h" |
f645cfa7 | 49 | #include "../libringbuffer/tlsfixup.h" |
edaa1431 MD |
50 | |
51 | /* | |
52 | * Has lttng ust comm constructor been called ? | |
53 | */ | |
54 | static int initialized; | |
55 | ||
1ea11eab | 56 | /* |
17dfb34b MD |
57 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
58 | * Held when handling a command, also held by fork() to deal with | |
59 | * removal of threads, and by exit path. | |
1ea11eab | 60 | */ |
1ea11eab MD |
61 | |
62 | /* Should the ust comm thread quit ? */ | |
63 | static int lttng_ust_comm_should_quit; | |
64 | ||
11ff9c7d MD |
65 | /* |
66 | * Wait for either of these before continuing to the main | |
67 | * program: | |
68 | * - the register_done message from sessiond daemon | |
69 | * (will let the sessiond daemon enable sessions before main | |
70 | * starts.) | |
71 | * - sessiond daemon is not reachable. | |
72 | * - timeout (ensuring applications are resilient to session | |
73 | * daemon problems). | |
74 | */ | |
75 | static sem_t constructor_wait; | |
950aab0c MD |
76 | /* |
77 | * Doing this for both the global and local sessiond. | |
78 | */ | |
95259bd0 | 79 | static int sem_count = { 2 }; |
11ff9c7d | 80 | |
e8508a49 MD |
81 | /* |
82 | * Counting nesting within lttng-ust. Used to ensure that calling fork() | |
83 | * from liblttng-ust does not execute the pre/post fork handlers. | |
84 | */ | |
85 | static int __thread lttng_ust_nest_count; | |
86 | ||
1ea11eab MD |
87 | /* |
88 | * Info about socket and associated listener thread. | |
89 | */ | |
90 | struct sock_info { | |
11ff9c7d | 91 | const char *name; |
1ea11eab | 92 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 93 | int root_handle; |
8d20bf54 MD |
94 | int constructor_sem_posted; |
95 | int allowed; | |
44e073f5 | 96 | int global; |
7fc90dca MD |
97 | |
98 | char sock_path[PATH_MAX]; | |
99 | int socket; | |
100 | ||
101 | char wait_shm_path[PATH_MAX]; | |
102 | char *wait_shm_mmap; | |
1ea11eab | 103 | }; |
2691221a MD |
104 | |
105 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 106 | struct sock_info global_apps = { |
11ff9c7d | 107 | .name = "global", |
44e073f5 | 108 | .global = 1, |
7fc90dca | 109 | |
46050b1a | 110 | .root_handle = -1, |
8d20bf54 | 111 | .allowed = 1, |
7fc90dca MD |
112 | |
113 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
114 | .socket = -1, | |
115 | ||
116 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 117 | }; |
2691221a MD |
118 | |
119 | /* TODO: allow global_apps_sock_path override */ | |
120 | ||
1ea11eab | 121 | struct sock_info local_apps = { |
11ff9c7d | 122 | .name = "local", |
44e073f5 | 123 | .global = 0, |
46050b1a | 124 | .root_handle = -1, |
8d20bf54 | 125 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
126 | |
127 | .socket = -1, | |
1ea11eab | 128 | }; |
2691221a | 129 | |
37ed587a MD |
130 | static int wait_poll_fallback; |
131 | ||
edaa1431 MD |
132 | extern void ltt_ring_buffer_client_overwrite_init(void); |
133 | extern void ltt_ring_buffer_client_discard_init(void); | |
134 | extern void ltt_ring_buffer_metadata_client_init(void); | |
135 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
136 | extern void ltt_ring_buffer_client_discard_exit(void); | |
137 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
138 | ||
a903623f MD |
139 | /* |
140 | * Force a read (imply TLS fixup for dlopen) of TLS variables. | |
141 | */ | |
142 | static | |
143 | void lttng_fixup_nest_count_tls(void) | |
144 | { | |
145 | asm volatile ("" : : "m" (lttng_ust_nest_count)); | |
146 | } | |
147 | ||
2691221a | 148 | static |
8d20bf54 | 149 | int setup_local_apps(void) |
2691221a MD |
150 | { |
151 | const char *home_dir; | |
7fc90dca | 152 | uid_t uid; |
2691221a | 153 | |
7fc90dca | 154 | uid = getuid(); |
8d20bf54 MD |
155 | /* |
156 | * Disallow per-user tracing for setuid binaries. | |
157 | */ | |
7fc90dca | 158 | if (uid != geteuid()) { |
8d20bf54 | 159 | local_apps.allowed = 0; |
d0a1ae63 | 160 | return 0; |
8d20bf54 MD |
161 | } else { |
162 | local_apps.allowed = 1; | |
163 | } | |
2691221a MD |
164 | home_dir = (const char *) getenv("HOME"); |
165 | if (!home_dir) | |
166 | return -ENOENT; | |
1ea11eab | 167 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 168 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
169 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
170 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
171 | return 0; |
172 | } | |
173 | ||
174 | static | |
175 | int register_app_to_sessiond(int socket) | |
176 | { | |
177 | ssize_t ret; | |
178 | struct { | |
e44418f3 MD |
179 | uint32_t major; |
180 | uint32_t minor; | |
2691221a | 181 | pid_t pid; |
5c33bde8 | 182 | pid_t ppid; |
2691221a | 183 | uid_t uid; |
83610856 | 184 | gid_t gid; |
c117fb1b | 185 | uint32_t bits_per_long; |
2629549e | 186 | char name[16]; /* process name */ |
2691221a MD |
187 | } reg_msg; |
188 | ||
e44418f3 MD |
189 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
190 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 191 | reg_msg.pid = getpid(); |
5c33bde8 | 192 | reg_msg.ppid = getppid(); |
2691221a | 193 | reg_msg.uid = getuid(); |
83610856 | 194 | reg_msg.gid = getgid(); |
c117fb1b | 195 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
08114193 | 196 | lttng_ust_getprocname(reg_msg.name); |
2691221a | 197 | |
57773204 | 198 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
199 | if (ret >= 0 && ret != sizeof(reg_msg)) |
200 | return -EIO; | |
201 | return ret; | |
202 | } | |
203 | ||
d9e99d10 | 204 | static |
57773204 | 205 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 206 | { |
9eb62b9c | 207 | ssize_t len; |
d3a492d1 | 208 | |
57773204 | 209 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 210 | switch (len) { |
a4be8962 | 211 | case sizeof(*lur): |
d3a492d1 MD |
212 | DBG("message successfully sent"); |
213 | return 0; | |
214 | case -1: | |
215 | if (errno == ECONNRESET) { | |
216 | printf("remote end closed connection\n"); | |
217 | return 0; | |
218 | } | |
219 | return -1; | |
220 | default: | |
221 | printf("incorrect message size: %zd\n", len); | |
222 | return -1; | |
223 | } | |
224 | } | |
225 | ||
226 | static | |
edaa1431 | 227 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
228 | { |
229 | int ret; | |
230 | ||
edaa1431 MD |
231 | if (sock_info->constructor_sem_posted) |
232 | return 0; | |
233 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
234 | if (uatomic_read(&sem_count) <= 0) { |
235 | return 0; | |
236 | } | |
95259bd0 MD |
237 | ret = uatomic_add_return(&sem_count, -1); |
238 | if (ret == 0) { | |
239 | ret = sem_post(&constructor_wait); | |
240 | assert(!ret); | |
241 | } | |
11ff9c7d MD |
242 | return 0; |
243 | } | |
244 | ||
245 | static | |
246 | int handle_message(struct sock_info *sock_info, | |
57773204 | 247 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 248 | { |
1ea11eab | 249 | int ret = 0; |
b61ce3b2 | 250 | const struct lttng_ust_objd_ops *ops; |
57773204 | 251 | struct ustcomm_ust_reply lur; |
193183fb | 252 | int shm_fd, wait_fd; |
ef9ff354 | 253 | union ust_args args; |
40003310 | 254 | ssize_t len; |
1ea11eab | 255 | |
17dfb34b | 256 | ust_lock(); |
1ea11eab | 257 | |
46050b1a MD |
258 | memset(&lur, 0, sizeof(lur)); |
259 | ||
1ea11eab | 260 | if (lttng_ust_comm_should_quit) { |
46050b1a | 261 | ret = -EPERM; |
1ea11eab MD |
262 | goto end; |
263 | } | |
9eb62b9c | 264 | |
46050b1a MD |
265 | ops = objd_ops(lum->handle); |
266 | if (!ops) { | |
267 | ret = -ENOENT; | |
268 | goto end; | |
1ea11eab | 269 | } |
46050b1a MD |
270 | |
271 | switch (lum->cmd) { | |
11ff9c7d MD |
272 | case LTTNG_UST_REGISTER_DONE: |
273 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 274 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
275 | else |
276 | ret = -EINVAL; | |
277 | break; | |
46050b1a MD |
278 | case LTTNG_UST_RELEASE: |
279 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
280 | ret = -EPERM; | |
281 | else | |
d4419b81 | 282 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 | 283 | break; |
2d78951a MD |
284 | case LTTNG_UST_FILTER: |
285 | { | |
286 | /* Receive filter data */ | |
287 | struct { | |
288 | uint16_t len; | |
289 | uint16_t reloc_offset; | |
290 | char data[FILTER_BYTECODE_MAX_LEN]; | |
291 | } filter_data; | |
292 | ||
293 | if (lum->u.filter.data_size > 65536) { | |
294 | ERR("Filter data size is too large: %u bytes\n", | |
295 | lum->u.filter.data_size); | |
296 | ret = -EINVAL; | |
297 | goto error; | |
298 | } | |
299 | len = ustcomm_recv_unix_sock(sock, filter_data.data, | |
300 | lum->u.filter.data_size); | |
301 | switch (len) { | |
302 | case 0: /* orderly shutdown */ | |
303 | ret = 0; | |
304 | goto error; | |
305 | case -1: | |
306 | DBG("Receive failed from lttng-sessiond with errno %d", errno); | |
307 | if (errno == ECONNRESET) { | |
308 | ERR("%s remote end closed connection\n", sock_info->name); | |
309 | ret = -EINVAL; | |
310 | goto error; | |
311 | } | |
312 | ret = -EINVAL; | |
313 | goto end; | |
314 | default: | |
315 | if (len == lum->u.filter.data_size) { | |
316 | DBG("filter data received\n"); | |
317 | break; | |
318 | } else { | |
319 | ERR("incorrect filter data message size: %zd\n", len); | |
320 | ret = -EINVAL; | |
321 | goto end; | |
322 | } | |
323 | } | |
324 | filter_data.len = lum->u.filter.data_size; | |
325 | filter_data.reloc_offset = lum->u.filter.reloc_offset; | |
326 | if (ops->cmd) | |
327 | ret = ops->cmd(lum->handle, lum->cmd, | |
328 | (unsigned long) &filter_data, | |
329 | &args); | |
330 | else | |
331 | ret = -ENOSYS; | |
332 | break; | |
333 | } | |
d9e99d10 | 334 | default: |
46050b1a MD |
335 | if (ops->cmd) |
336 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
337 | (unsigned long) &lum->u, |
338 | &args); | |
46050b1a MD |
339 | else |
340 | ret = -ENOSYS; | |
341 | break; | |
d9e99d10 | 342 | } |
46050b1a | 343 | |
1ea11eab | 344 | end: |
46050b1a MD |
345 | lur.handle = lum->handle; |
346 | lur.cmd = lum->cmd; | |
347 | lur.ret_val = ret; | |
348 | if (ret >= 0) { | |
57773204 | 349 | lur.ret_code = USTCOMM_OK; |
46050b1a | 350 | } else { |
57773204 | 351 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 352 | lur.ret_code = ret; |
46050b1a | 353 | } |
e6ea14c5 MD |
354 | if (ret >= 0) { |
355 | switch (lum->cmd) { | |
356 | case LTTNG_UST_STREAM: | |
357 | /* | |
358 | * Special-case reply to send stream info. | |
359 | * Use lum.u output. | |
360 | */ | |
361 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; | |
362 | shm_fd = *args.stream.shm_fd; | |
363 | wait_fd = *args.stream.wait_fd; | |
364 | break; | |
365 | case LTTNG_UST_METADATA: | |
366 | case LTTNG_UST_CHANNEL: | |
367 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; | |
368 | shm_fd = *args.channel.shm_fd; | |
369 | wait_fd = *args.channel.wait_fd; | |
370 | break; | |
371 | case LTTNG_UST_TRACER_VERSION: | |
372 | lur.u.version = lum->u.version; | |
373 | break; | |
374 | case LTTNG_UST_TRACEPOINT_LIST_GET: | |
375 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); | |
376 | break; | |
377 | } | |
381c0f1e | 378 | } |
46050b1a | 379 | ret = send_reply(sock, &lur); |
193183fb MD |
380 | if (ret < 0) { |
381 | perror("error sending reply"); | |
382 | goto error; | |
383 | } | |
46050b1a | 384 | |
824f40b8 MD |
385 | if ((lum->cmd == LTTNG_UST_STREAM |
386 | || lum->cmd == LTTNG_UST_CHANNEL | |
387 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 388 | && lur.ret_code == USTCOMM_OK) { |
50be2fc4 MD |
389 | int sendret = 0; |
390 | ||
381c0f1e | 391 | /* we also need to send the file descriptors. */ |
57773204 | 392 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 393 | &shm_fd, &shm_fd, |
381c0f1e MD |
394 | 1, sizeof(int)); |
395 | if (ret < 0) { | |
396 | perror("send shm_fd"); | |
50be2fc4 | 397 | sendret = ret; |
381c0f1e | 398 | } |
50be2fc4 MD |
399 | /* |
400 | * The sessiond expects 2 file descriptors, even upon | |
401 | * error. | |
402 | */ | |
57773204 | 403 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 404 | &wait_fd, &wait_fd, |
381c0f1e MD |
405 | 1, sizeof(int)); |
406 | if (ret < 0) { | |
407 | perror("send wait_fd"); | |
408 | goto error; | |
409 | } | |
50be2fc4 MD |
410 | if (sendret) { |
411 | ret = sendret; | |
412 | goto error; | |
413 | } | |
381c0f1e | 414 | } |
40003310 MD |
415 | /* |
416 | * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field | |
417 | * after the reply. | |
418 | */ | |
419 | if (lur.ret_code == USTCOMM_OK) { | |
420 | switch (lum->cmd) { | |
421 | case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET: | |
422 | len = ustcomm_send_unix_sock(sock, | |
423 | &args.field_list.entry, | |
424 | sizeof(args.field_list.entry)); | |
425 | if (len != sizeof(args.field_list.entry)) { | |
426 | ret = -1; | |
427 | goto error; | |
428 | } | |
429 | } | |
430 | } | |
ef9ff354 MD |
431 | /* |
432 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
433 | * sent to the sessiond. We can therefore close those fds. Note |
434 | * that we keep the write side of the wait_fd open, but close | |
435 | * the read side. | |
ef9ff354 MD |
436 | */ |
437 | if (lur.ret_code == USTCOMM_OK) { | |
438 | switch (lum->cmd) { | |
439 | case LTTNG_UST_STREAM: | |
440 | if (shm_fd >= 0) { | |
441 | ret = close(shm_fd); | |
442 | if (ret) { | |
443 | PERROR("Error closing stream shm_fd"); | |
444 | } | |
445 | *args.stream.shm_fd = -1; | |
446 | } | |
447 | if (wait_fd >= 0) { | |
448 | ret = close(wait_fd); | |
449 | if (ret) { | |
450 | PERROR("Error closing stream wait_fd"); | |
451 | } | |
452 | *args.stream.wait_fd = -1; | |
453 | } | |
454 | break; | |
455 | case LTTNG_UST_METADATA: | |
456 | case LTTNG_UST_CHANNEL: | |
457 | if (shm_fd >= 0) { | |
458 | ret = close(shm_fd); | |
459 | if (ret) { | |
460 | PERROR("Error closing channel shm_fd"); | |
461 | } | |
462 | *args.channel.shm_fd = -1; | |
463 | } | |
464 | if (wait_fd >= 0) { | |
465 | ret = close(wait_fd); | |
466 | if (ret) { | |
467 | PERROR("Error closing channel wait_fd"); | |
468 | } | |
469 | *args.channel.wait_fd = -1; | |
470 | } | |
471 | break; | |
472 | } | |
473 | } | |
474 | ||
381c0f1e | 475 | error: |
17dfb34b | 476 | ust_unlock(); |
1ea11eab | 477 | return ret; |
d9e99d10 MD |
478 | } |
479 | ||
46050b1a | 480 | static |
efe0de09 | 481 | void cleanup_sock_info(struct sock_info *sock_info, int exiting) |
46050b1a MD |
482 | { |
483 | int ret; | |
484 | ||
485 | if (sock_info->socket != -1) { | |
e6973a89 | 486 | ret = ustcomm_close_unix_sock(sock_info->socket); |
46050b1a | 487 | if (ret) { |
7fc90dca | 488 | ERR("Error closing apps socket"); |
46050b1a MD |
489 | } |
490 | sock_info->socket = -1; | |
491 | } | |
492 | if (sock_info->root_handle != -1) { | |
d4419b81 | 493 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
494 | if (ret) { |
495 | ERR("Error unref root handle"); | |
496 | } | |
497 | sock_info->root_handle = -1; | |
498 | } | |
318dfea9 | 499 | sock_info->constructor_sem_posted = 0; |
efe0de09 MD |
500 | /* |
501 | * wait_shm_mmap is used by listener threads outside of the | |
502 | * ust lock, so we cannot tear it down ourselves, because we | |
503 | * cannot join on these threads. Leave this task to the OS | |
504 | * process exit. | |
505 | */ | |
506 | if (!exiting && sock_info->wait_shm_mmap) { | |
7fc90dca MD |
507 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); |
508 | if (ret) { | |
509 | ERR("Error unmapping wait shm"); | |
510 | } | |
511 | sock_info->wait_shm_mmap = NULL; | |
512 | } | |
513 | } | |
514 | ||
58d4b2a2 | 515 | /* |
33bbeb90 MD |
516 | * Using fork to set umask in the child process (not multi-thread safe). |
517 | * We deal with the shm_open vs ftruncate race (happening when the | |
518 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
519 | * safety against shm_unlink) by simply letting the mmap fail and | |
520 | * retrying after a few seconds. | |
521 | * For global shm, everybody has rw access to it until the sessiond | |
522 | * starts. | |
58d4b2a2 | 523 | */ |
7fc90dca | 524 | static |
58d4b2a2 | 525 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 526 | { |
7fc90dca | 527 | int wait_shm_fd, ret; |
58d4b2a2 | 528 | pid_t pid; |
44e073f5 | 529 | |
58d4b2a2 | 530 | /* |
33bbeb90 | 531 | * Try to open read-only. |
58d4b2a2 | 532 | */ |
33bbeb90 | 533 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
534 | if (wait_shm_fd >= 0) { |
535 | goto end; | |
536 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
537 | /* | |
33bbeb90 MD |
538 | * Real-only open did not work, and it's not because the |
539 | * entry was not present. It's a failure that prohibits | |
540 | * using shm. | |
58d4b2a2 | 541 | */ |
7fc90dca | 542 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 543 | goto end; |
7fc90dca MD |
544 | } |
545 | /* | |
58d4b2a2 MD |
546 | * If the open failed because the file did not exist, try |
547 | * creating it ourself. | |
7fc90dca | 548 | */ |
e8508a49 | 549 | lttng_ust_nest_count++; |
58d4b2a2 | 550 | pid = fork(); |
e8508a49 | 551 | lttng_ust_nest_count--; |
58d4b2a2 MD |
552 | if (pid > 0) { |
553 | int status; | |
554 | ||
555 | /* | |
556 | * Parent: wait for child to return, in which case the | |
557 | * shared memory map will have been created. | |
558 | */ | |
559 | pid = wait(&status); | |
b7d3cb32 | 560 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
561 | wait_shm_fd = -1; |
562 | goto end; | |
7fc90dca | 563 | } |
58d4b2a2 MD |
564 | /* |
565 | * Try to open read-only again after creation. | |
566 | */ | |
33bbeb90 | 567 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
568 | if (wait_shm_fd < 0) { |
569 | /* | |
570 | * Real-only open did not work. It's a failure | |
571 | * that prohibits using shm. | |
572 | */ | |
573 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
574 | goto end; | |
575 | } | |
576 | goto end; | |
577 | } else if (pid == 0) { | |
578 | int create_mode; | |
579 | ||
580 | /* Child */ | |
33bbeb90 | 581 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 582 | if (sock_info->global) |
33bbeb90 | 583 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
584 | /* |
585 | * We're alone in a child process, so we can modify the | |
586 | * process-wide umask. | |
587 | */ | |
33bbeb90 | 588 | umask(~create_mode); |
58d4b2a2 | 589 | /* |
33bbeb90 MD |
590 | * Try creating shm (or get rw access). |
591 | * We don't do an exclusive open, because we allow other | |
592 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
593 | */ |
594 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
595 | O_RDWR | O_CREAT, create_mode); | |
596 | if (wait_shm_fd >= 0) { | |
597 | ret = ftruncate(wait_shm_fd, mmap_size); | |
598 | if (ret) { | |
599 | PERROR("ftruncate"); | |
600 | exit(EXIT_FAILURE); | |
601 | } | |
58d4b2a2 MD |
602 | exit(EXIT_SUCCESS); |
603 | } | |
33bbeb90 MD |
604 | /* |
605 | * For local shm, we need to have rw access to accept | |
606 | * opening it: this means the local sessiond will be | |
607 | * able to wake us up. For global shm, we open it even | |
608 | * if rw access is not granted, because the root.root | |
609 | * sessiond will be able to override all rights and wake | |
610 | * us up. | |
611 | */ | |
612 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
613 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
614 | exit(EXIT_FAILURE); | |
615 | } | |
616 | /* | |
33bbeb90 MD |
617 | * The shm exists, but we cannot open it RW. Report |
618 | * success. | |
58d4b2a2 MD |
619 | */ |
620 | exit(EXIT_SUCCESS); | |
621 | } else { | |
622 | return -1; | |
7fc90dca | 623 | } |
58d4b2a2 | 624 | end: |
33bbeb90 MD |
625 | if (wait_shm_fd >= 0 && !sock_info->global) { |
626 | struct stat statbuf; | |
627 | ||
628 | /* | |
629 | * Ensure that our user is the owner of the shm file for | |
630 | * local shm. If we do not own the file, it means our | |
631 | * sessiond will not have access to wake us up (there is | |
632 | * probably a rogue process trying to fake our | |
633 | * sessiond). Fallback to polling method in this case. | |
634 | */ | |
635 | ret = fstat(wait_shm_fd, &statbuf); | |
636 | if (ret) { | |
637 | PERROR("fstat"); | |
638 | goto error_close; | |
639 | } | |
640 | if (statbuf.st_uid != getuid()) | |
641 | goto error_close; | |
642 | } | |
58d4b2a2 | 643 | return wait_shm_fd; |
33bbeb90 MD |
644 | |
645 | error_close: | |
646 | ret = close(wait_shm_fd); | |
647 | if (ret) { | |
648 | PERROR("Error closing fd"); | |
649 | } | |
650 | return -1; | |
58d4b2a2 MD |
651 | } |
652 | ||
653 | static | |
654 | char *get_map_shm(struct sock_info *sock_info) | |
655 | { | |
656 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
657 | int wait_shm_fd, ret; | |
658 | char *wait_shm_mmap; | |
659 | ||
660 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
661 | if (wait_shm_fd < 0) { | |
662 | goto error; | |
44e073f5 | 663 | } |
7fc90dca MD |
664 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
665 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
666 | /* close shm fd immediately after taking the mmap reference */ |
667 | ret = close(wait_shm_fd); | |
668 | if (ret) { | |
33bbeb90 MD |
669 | PERROR("Error closing fd"); |
670 | } | |
671 | if (wait_shm_mmap == MAP_FAILED) { | |
672 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
673 | goto error; | |
7fc90dca MD |
674 | } |
675 | return wait_shm_mmap; | |
676 | ||
677 | error: | |
678 | return NULL; | |
679 | } | |
680 | ||
681 | static | |
682 | void wait_for_sessiond(struct sock_info *sock_info) | |
683 | { | |
efe0de09 | 684 | int ret; |
80e2814b | 685 | |
7fc90dca MD |
686 | ust_lock(); |
687 | if (lttng_ust_comm_should_quit) { | |
688 | goto quit; | |
689 | } | |
37ed587a MD |
690 | if (wait_poll_fallback) { |
691 | goto error; | |
692 | } | |
7fc90dca MD |
693 | if (!sock_info->wait_shm_mmap) { |
694 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
695 | if (!sock_info->wait_shm_mmap) | |
696 | goto error; | |
697 | } | |
698 | ust_unlock(); | |
699 | ||
700 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
701 | /* Wait for futex wakeup */ |
702 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
703 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
704 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 705 | if (ret < 0) { |
37ed587a MD |
706 | if (errno == EFAULT) { |
707 | wait_poll_fallback = 1; | |
a8b870ad | 708 | DBG( |
37ed587a MD |
709 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
710 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
711 | "Please upgrade your kernel " | |
712 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
713 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
714 | if (ust_debug()) |
715 | PERROR("futex"); | |
37ed587a | 716 | } |
80e2814b MD |
717 | } |
718 | } | |
7fc90dca MD |
719 | return; |
720 | ||
721 | quit: | |
722 | ust_unlock(); | |
723 | return; | |
724 | ||
725 | error: | |
726 | ust_unlock(); | |
7fc90dca | 727 | return; |
46050b1a MD |
728 | } |
729 | ||
1ea11eab MD |
730 | /* |
731 | * This thread does not allocate any resource, except within | |
732 | * handle_message, within mutex protection. This mutex protects against | |
733 | * fork and exit. | |
98bf993f | 734 | * The other moment it allocates resources is at socket connection, which |
1ea11eab MD |
735 | * is also protected by the mutex. |
736 | */ | |
d9e99d10 MD |
737 | static |
738 | void *ust_listener_thread(void *arg) | |
739 | { | |
1ea11eab | 740 | struct sock_info *sock_info = arg; |
c0eedf81 | 741 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 742 | |
9eb62b9c MD |
743 | /* Restart trying to connect to the session daemon */ |
744 | restart: | |
c0eedf81 MD |
745 | if (prev_connect_failed) { |
746 | /* Wait for sessiond availability with pipe */ | |
747 | wait_for_sessiond(sock_info); | |
748 | if (has_waited) { | |
749 | has_waited = 0; | |
750 | /* | |
751 | * Sleep for 5 seconds before retrying after a | |
752 | * sequence of failure / wait / failure. This | |
753 | * deals with a killed or broken session daemon. | |
754 | */ | |
755 | sleep(5); | |
756 | } | |
757 | has_waited = 1; | |
758 | prev_connect_failed = 0; | |
759 | } | |
17dfb34b | 760 | ust_lock(); |
1ea11eab MD |
761 | |
762 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 763 | ust_unlock(); |
1ea11eab MD |
764 | goto quit; |
765 | } | |
9eb62b9c | 766 | |
1ea11eab | 767 | if (sock_info->socket != -1) { |
e6973a89 | 768 | ret = ustcomm_close_unix_sock(sock_info->socket); |
1ea11eab | 769 | if (ret) { |
11ff9c7d | 770 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
771 | } |
772 | sock_info->socket = -1; | |
773 | } | |
46050b1a | 774 | |
9eb62b9c | 775 | /* Register */ |
57773204 | 776 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 777 | if (ret < 0) { |
4d3c9523 | 778 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 779 | prev_connect_failed = 1; |
11ff9c7d MD |
780 | /* |
781 | * If we cannot find the sessiond daemon, don't delay | |
782 | * constructor execution. | |
783 | */ | |
edaa1431 | 784 | ret = handle_register_done(sock_info); |
11ff9c7d | 785 | assert(!ret); |
17dfb34b | 786 | ust_unlock(); |
1ea11eab | 787 | goto restart; |
46050b1a MD |
788 | } |
789 | ||
790 | sock_info->socket = sock = ret; | |
791 | ||
792 | /* | |
793 | * Create only one root handle per listener thread for the whole | |
794 | * process lifetime. | |
795 | */ | |
796 | if (sock_info->root_handle == -1) { | |
797 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 798 | if (ret < 0) { |
46050b1a | 799 | ERR("Error creating root handle"); |
17dfb34b | 800 | ust_unlock(); |
46050b1a MD |
801 | goto quit; |
802 | } | |
803 | sock_info->root_handle = ret; | |
9eb62b9c | 804 | } |
1ea11eab | 805 | |
9eb62b9c MD |
806 | ret = register_app_to_sessiond(sock); |
807 | if (ret < 0) { | |
11ff9c7d | 808 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 809 | prev_connect_failed = 1; |
11ff9c7d MD |
810 | /* |
811 | * If we cannot register to the sessiond daemon, don't | |
812 | * delay constructor execution. | |
813 | */ | |
edaa1431 | 814 | ret = handle_register_done(sock_info); |
11ff9c7d | 815 | assert(!ret); |
17dfb34b | 816 | ust_unlock(); |
9eb62b9c MD |
817 | goto restart; |
818 | } | |
17dfb34b | 819 | ust_unlock(); |
46050b1a | 820 | |
d9e99d10 MD |
821 | for (;;) { |
822 | ssize_t len; | |
57773204 | 823 | struct ustcomm_ust_msg lum; |
d9e99d10 | 824 | |
57773204 | 825 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
826 | switch (len) { |
827 | case 0: /* orderly shutdown */ | |
11ff9c7d | 828 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
829 | ust_lock(); |
830 | /* | |
831 | * Either sessiond has shutdown or refused us by closing the socket. | |
832 | * In either case, we don't want to delay construction execution, | |
833 | * and we need to wait before retry. | |
834 | */ | |
835 | prev_connect_failed = 1; | |
836 | /* | |
837 | * If we cannot register to the sessiond daemon, don't | |
838 | * delay constructor execution. | |
839 | */ | |
840 | ret = handle_register_done(sock_info); | |
841 | assert(!ret); | |
842 | ust_unlock(); | |
d9e99d10 | 843 | goto end; |
e7723462 | 844 | case sizeof(lum): |
d9e99d10 | 845 | DBG("message received\n"); |
11ff9c7d | 846 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 847 | if (ret < 0) { |
11ff9c7d | 848 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
849 | } |
850 | continue; | |
851 | case -1: | |
8236ba10 | 852 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 853 | if (errno == ECONNRESET) { |
11ff9c7d | 854 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
855 | goto end; |
856 | } | |
857 | goto end; | |
858 | default: | |
11ff9c7d | 859 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
860 | continue; |
861 | } | |
862 | ||
863 | } | |
864 | end: | |
9eb62b9c | 865 | goto restart; /* try to reconnect */ |
1ea11eab | 866 | quit: |
d9e99d10 MD |
867 | return NULL; |
868 | } | |
869 | ||
cf12a773 MD |
870 | /* |
871 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
872 | */ | |
11ff9c7d MD |
873 | static |
874 | int get_timeout(struct timespec *constructor_timeout) | |
875 | { | |
cf12a773 MD |
876 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
877 | char *str_delay; | |
11ff9c7d MD |
878 | int ret; |
879 | ||
69400ac4 | 880 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
881 | if (str_delay) { |
882 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
883 | } | |
884 | ||
885 | switch (constructor_delay_ms) { | |
886 | case -1:/* fall-through */ | |
887 | case 0: | |
888 | return constructor_delay_ms; | |
889 | default: | |
890 | break; | |
891 | } | |
892 | ||
893 | /* | |
894 | * If we are unable to find the current time, don't wait. | |
895 | */ | |
896 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
897 | if (ret) { | |
898 | return -1; | |
899 | } | |
95259bd0 MD |
900 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
901 | constructor_timeout->tv_nsec += | |
902 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
903 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
904 | constructor_timeout->tv_sec++; | |
905 | constructor_timeout->tv_nsec -= 1000000000UL; | |
906 | } | |
cf12a773 | 907 | return 1; |
11ff9c7d | 908 | } |
d9e99d10 | 909 | |
2691221a MD |
910 | /* |
911 | * sessiond monitoring thread: monitor presence of global and per-user | |
912 | * sessiond by polling the application common named pipe. | |
913 | */ | |
914 | /* TODO */ | |
915 | ||
edaa1431 | 916 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 917 | { |
11ff9c7d | 918 | struct timespec constructor_timeout; |
ae6a58bf | 919 | sigset_t sig_all_blocked, orig_parent_mask; |
cf12a773 | 920 | int timeout_mode; |
2691221a MD |
921 | int ret; |
922 | ||
edaa1431 MD |
923 | if (uatomic_xchg(&initialized, 1) == 1) |
924 | return; | |
925 | ||
eddd8d5d MD |
926 | /* |
927 | * Fixup interdependency between TLS fixup mutex (which happens | |
928 | * to be the dynamic linker mutex) and ust_lock, taken within | |
929 | * the ust lock. | |
930 | */ | |
931 | lttng_fixup_event_tls(); | |
f645cfa7 | 932 | lttng_fixup_ringbuffer_tls(); |
4158a15a | 933 | lttng_fixup_vtid_tls(); |
a903623f | 934 | lttng_fixup_nest_count_tls(); |
eddd8d5d | 935 | |
edaa1431 MD |
936 | /* |
937 | * We want precise control over the order in which we construct | |
938 | * our sub-libraries vs starting to receive commands from | |
939 | * sessiond (otherwise leading to errors when trying to create | |
940 | * sessiond before the init functions are completed). | |
941 | */ | |
2691221a | 942 | init_usterr(); |
edaa1431 MD |
943 | init_tracepoint(); |
944 | ltt_ring_buffer_metadata_client_init(); | |
945 | ltt_ring_buffer_client_overwrite_init(); | |
946 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 947 | |
cf12a773 | 948 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 949 | |
95259bd0 | 950 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
951 | assert(!ret); |
952 | ||
8d20bf54 | 953 | ret = setup_local_apps(); |
2691221a | 954 | if (ret) { |
8d20bf54 | 955 | ERR("Error setting up to local apps"); |
2691221a | 956 | } |
ae6a58bf WP |
957 | |
958 | /* A new thread created by pthread_create inherits the signal mask | |
959 | * from the parent. To avoid any signal being received by the | |
960 | * listener thread, we block all signals temporarily in the parent, | |
961 | * while we create the listener thread. | |
962 | */ | |
963 | sigfillset(&sig_all_blocked); | |
964 | ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask); | |
965 | if (ret) { | |
d94d802c | 966 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
967 | } |
968 | ||
dde70ea0 MD |
969 | ret = pthread_create(&global_apps.ust_listener, NULL, |
970 | ust_listener_thread, &global_apps); | |
d94d802c MD |
971 | if (ret) { |
972 | ERR("pthread_create global: %s", strerror(ret)); | |
973 | } | |
8d20bf54 | 974 | if (local_apps.allowed) { |
dde70ea0 MD |
975 | ret = pthread_create(&local_apps.ust_listener, NULL, |
976 | ust_listener_thread, &local_apps); | |
d94d802c MD |
977 | if (ret) { |
978 | ERR("pthread_create local: %s", strerror(ret)); | |
979 | } | |
8d20bf54 MD |
980 | } else { |
981 | handle_register_done(&local_apps); | |
982 | } | |
983 | ||
ae6a58bf WP |
984 | /* Restore original signal mask in parent */ |
985 | ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL); | |
986 | if (ret) { | |
d94d802c | 987 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
988 | } |
989 | ||
cf12a773 MD |
990 | switch (timeout_mode) { |
991 | case 1: /* timeout wait */ | |
95259bd0 MD |
992 | do { |
993 | ret = sem_timedwait(&constructor_wait, | |
994 | &constructor_timeout); | |
995 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
996 | if (ret < 0 && errno == ETIMEDOUT) { |
997 | ERR("Timed out waiting for ltt-sessiond"); | |
998 | } else { | |
999 | assert(!ret); | |
1000 | } | |
1001 | break; | |
7b766b16 | 1002 | case -1:/* wait forever */ |
95259bd0 MD |
1003 | do { |
1004 | ret = sem_wait(&constructor_wait); | |
1005 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 1006 | assert(!ret); |
cf12a773 | 1007 | break; |
7b766b16 | 1008 | case 0: /* no timeout */ |
cf12a773 | 1009 | break; |
11ff9c7d | 1010 | } |
2691221a MD |
1011 | } |
1012 | ||
17dfb34b MD |
1013 | static |
1014 | void lttng_ust_cleanup(int exiting) | |
1015 | { | |
efe0de09 | 1016 | cleanup_sock_info(&global_apps, exiting); |
17dfb34b | 1017 | if (local_apps.allowed) { |
efe0de09 | 1018 | cleanup_sock_info(&local_apps, exiting); |
17dfb34b | 1019 | } |
efe0de09 MD |
1020 | /* |
1021 | * The teardown in this function all affect data structures | |
1022 | * accessed under the UST lock by the listener thread. This | |
1023 | * lock, along with the lttng_ust_comm_should_quit flag, ensure | |
1024 | * that none of these threads are accessing this data at this | |
1025 | * point. | |
1026 | */ | |
17dfb34b | 1027 | lttng_ust_abi_exit(); |
003fedf4 | 1028 | lttng_ust_events_exit(); |
17dfb34b MD |
1029 | ltt_ring_buffer_client_discard_exit(); |
1030 | ltt_ring_buffer_client_overwrite_exit(); | |
1031 | ltt_ring_buffer_metadata_client_exit(); | |
1032 | exit_tracepoint(); | |
1033 | if (!exiting) { | |
1034 | /* Reinitialize values for fork */ | |
1035 | sem_count = 2; | |
1036 | lttng_ust_comm_should_quit = 0; | |
1037 | initialized = 0; | |
1038 | } | |
1039 | } | |
1040 | ||
edaa1431 | 1041 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
1042 | { |
1043 | int ret; | |
1044 | ||
9eb62b9c MD |
1045 | /* |
1046 | * Using pthread_cancel here because: | |
1047 | * A) we don't want to hang application teardown. | |
1048 | * B) the thread is not allocating any resource. | |
1049 | */ | |
1ea11eab MD |
1050 | |
1051 | /* | |
1052 | * Require the communication thread to quit. Synchronize with | |
1053 | * mutexes to ensure it is not in a mutex critical section when | |
1054 | * pthread_cancel is later called. | |
1055 | */ | |
17dfb34b | 1056 | ust_lock(); |
1ea11eab | 1057 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 1058 | ust_unlock(); |
1ea11eab | 1059 | |
f5f94532 | 1060 | /* cancel threads */ |
1ea11eab | 1061 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c | 1062 | if (ret) { |
d94d802c MD |
1063 | ERR("Error cancelling global ust listener thread: %s", |
1064 | strerror(ret)); | |
2691221a | 1065 | } |
8d20bf54 MD |
1066 | if (local_apps.allowed) { |
1067 | ret = pthread_cancel(local_apps.ust_listener); | |
1068 | if (ret) { | |
d94d802c MD |
1069 | ERR("Error cancelling local ust listener thread: %s", |
1070 | strerror(ret)); | |
8d20bf54 | 1071 | } |
8d20bf54 | 1072 | } |
efe0de09 MD |
1073 | /* |
1074 | * Do NOT join threads: use of sys_futex makes it impossible to | |
1075 | * join the threads without using async-cancel, but async-cancel | |
1076 | * is delivered by a signal, which could hit the target thread | |
1077 | * anywhere in its code path, including while the ust_lock() is | |
1078 | * held, causing a deadlock for the other thread. Let the OS | |
1079 | * cleanup the threads if there are stalled in a syscall. | |
1080 | */ | |
17dfb34b | 1081 | lttng_ust_cleanup(1); |
2691221a | 1082 | } |
e822f505 MD |
1083 | |
1084 | /* | |
1085 | * We exclude the worker threads across fork and clone (except | |
1086 | * CLONE_VM), because these system calls only keep the forking thread | |
1087 | * running in the child. Therefore, we don't want to call fork or clone | |
1088 | * in the middle of an tracepoint or ust tracing state modification. | |
1089 | * Holding this mutex protects these structures across fork and clone. | |
1090 | */ | |
b728d87e | 1091 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
1092 | { |
1093 | /* | |
1094 | * Disable signals. This is to avoid that the child intervenes | |
1095 | * before it is properly setup for tracing. It is safer to | |
1096 | * disable all signals, because then we know we are not breaking | |
1097 | * anything by restoring the original mask. | |
1098 | */ | |
1099 | sigset_t all_sigs; | |
1100 | int ret; | |
1101 | ||
e8508a49 MD |
1102 | if (lttng_ust_nest_count) |
1103 | return; | |
e822f505 MD |
1104 | /* Disable signals */ |
1105 | sigfillset(&all_sigs); | |
b728d87e | 1106 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
1107 | if (ret == -1) { |
1108 | PERROR("sigprocmask"); | |
1109 | } | |
17dfb34b | 1110 | ust_lock(); |
e822f505 MD |
1111 | rcu_bp_before_fork(); |
1112 | } | |
1113 | ||
b728d87e | 1114 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
1115 | { |
1116 | int ret; | |
1117 | ||
17dfb34b MD |
1118 | DBG("process %d", getpid()); |
1119 | ust_unlock(); | |
e822f505 | 1120 | /* Restore signals */ |
23c8854a | 1121 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
1122 | if (ret == -1) { |
1123 | PERROR("sigprocmask"); | |
1124 | } | |
1125 | } | |
1126 | ||
b728d87e | 1127 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 1128 | { |
e8508a49 MD |
1129 | if (lttng_ust_nest_count) |
1130 | return; | |
17dfb34b | 1131 | DBG("process %d", getpid()); |
e822f505 MD |
1132 | rcu_bp_after_fork_parent(); |
1133 | /* Release mutexes and reenable signals */ | |
b728d87e | 1134 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
1135 | } |
1136 | ||
17dfb34b MD |
1137 | /* |
1138 | * After fork, in the child, we need to cleanup all the leftover state, | |
1139 | * except the worker thread which already magically disappeared thanks | |
1140 | * to the weird Linux fork semantics. After tyding up, we call | |
1141 | * lttng_ust_init() again to start over as a new PID. | |
1142 | * | |
1143 | * This is meant for forks() that have tracing in the child between the | |
1144 | * fork and following exec call (if there is any). | |
1145 | */ | |
b728d87e | 1146 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 1147 | { |
e8508a49 MD |
1148 | if (lttng_ust_nest_count) |
1149 | return; | |
17dfb34b | 1150 | DBG("process %d", getpid()); |
e822f505 MD |
1151 | /* Release urcu mutexes */ |
1152 | rcu_bp_after_fork_child(); | |
17dfb34b | 1153 | lttng_ust_cleanup(0); |
a93bfc45 | 1154 | lttng_context_vtid_reset(); |
e822f505 | 1155 | /* Release mutexes and reenable signals */ |
b728d87e | 1156 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1157 | lttng_ust_init(); |
e822f505 | 1158 | } |