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> |
7bc53e94 | 44 | #include <lttng/ust-error.h> |
44c72f10 MD |
45 | #include <ust-comm.h> |
46 | #include <usterr-signal-safe.h> | |
cd54f6d9 | 47 | #include <helper.h> |
44c72f10 | 48 | #include "tracepoint-internal.h" |
b751f722 | 49 | #include "ltt-tracer-core.h" |
08114193 | 50 | #include "compat.h" |
f645cfa7 | 51 | #include "../libringbuffer/tlsfixup.h" |
edaa1431 MD |
52 | |
53 | /* | |
54 | * Has lttng ust comm constructor been called ? | |
55 | */ | |
56 | static int initialized; | |
57 | ||
1ea11eab | 58 | /* |
17dfb34b MD |
59 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
60 | * Held when handling a command, also held by fork() to deal with | |
61 | * removal of threads, and by exit path. | |
1ea11eab | 62 | */ |
1ea11eab MD |
63 | |
64 | /* Should the ust comm thread quit ? */ | |
65 | static int lttng_ust_comm_should_quit; | |
66 | ||
11ff9c7d MD |
67 | /* |
68 | * Wait for either of these before continuing to the main | |
69 | * program: | |
70 | * - the register_done message from sessiond daemon | |
71 | * (will let the sessiond daemon enable sessions before main | |
72 | * starts.) | |
73 | * - sessiond daemon is not reachable. | |
74 | * - timeout (ensuring applications are resilient to session | |
75 | * daemon problems). | |
76 | */ | |
77 | static sem_t constructor_wait; | |
950aab0c MD |
78 | /* |
79 | * Doing this for both the global and local sessiond. | |
80 | */ | |
95259bd0 | 81 | static int sem_count = { 2 }; |
11ff9c7d | 82 | |
e8508a49 MD |
83 | /* |
84 | * Counting nesting within lttng-ust. Used to ensure that calling fork() | |
85 | * from liblttng-ust does not execute the pre/post fork handlers. | |
86 | */ | |
87 | static int __thread lttng_ust_nest_count; | |
88 | ||
1ea11eab MD |
89 | /* |
90 | * Info about socket and associated listener thread. | |
91 | */ | |
92 | struct sock_info { | |
11ff9c7d | 93 | const char *name; |
1ea11eab | 94 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 95 | int root_handle; |
8d20bf54 MD |
96 | int constructor_sem_posted; |
97 | int allowed; | |
44e073f5 | 98 | int global; |
7fc90dca MD |
99 | |
100 | char sock_path[PATH_MAX]; | |
101 | int socket; | |
102 | ||
103 | char wait_shm_path[PATH_MAX]; | |
104 | char *wait_shm_mmap; | |
1ea11eab | 105 | }; |
2691221a MD |
106 | |
107 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 108 | struct sock_info global_apps = { |
11ff9c7d | 109 | .name = "global", |
44e073f5 | 110 | .global = 1, |
7fc90dca | 111 | |
46050b1a | 112 | .root_handle = -1, |
8d20bf54 | 113 | .allowed = 1, |
7fc90dca MD |
114 | |
115 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
116 | .socket = -1, | |
117 | ||
118 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 119 | }; |
2691221a MD |
120 | |
121 | /* TODO: allow global_apps_sock_path override */ | |
122 | ||
1ea11eab | 123 | struct sock_info local_apps = { |
11ff9c7d | 124 | .name = "local", |
44e073f5 | 125 | .global = 0, |
46050b1a | 126 | .root_handle = -1, |
8d20bf54 | 127 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
128 | |
129 | .socket = -1, | |
1ea11eab | 130 | }; |
2691221a | 131 | |
37ed587a MD |
132 | static int wait_poll_fallback; |
133 | ||
edaa1431 MD |
134 | extern void ltt_ring_buffer_client_overwrite_init(void); |
135 | extern void ltt_ring_buffer_client_discard_init(void); | |
136 | extern void ltt_ring_buffer_metadata_client_init(void); | |
137 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
138 | extern void ltt_ring_buffer_client_discard_exit(void); | |
139 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
140 | ||
a903623f MD |
141 | /* |
142 | * Force a read (imply TLS fixup for dlopen) of TLS variables. | |
143 | */ | |
144 | static | |
145 | void lttng_fixup_nest_count_tls(void) | |
146 | { | |
147 | asm volatile ("" : : "m" (lttng_ust_nest_count)); | |
148 | } | |
149 | ||
2691221a | 150 | static |
8d20bf54 | 151 | int setup_local_apps(void) |
2691221a MD |
152 | { |
153 | const char *home_dir; | |
7fc90dca | 154 | uid_t uid; |
2691221a | 155 | |
7fc90dca | 156 | uid = getuid(); |
8d20bf54 MD |
157 | /* |
158 | * Disallow per-user tracing for setuid binaries. | |
159 | */ | |
7fc90dca | 160 | if (uid != geteuid()) { |
9ec6895c | 161 | assert(local_apps.allowed == 0); |
d0a1ae63 | 162 | return 0; |
8d20bf54 | 163 | } |
2691221a | 164 | home_dir = (const char *) getenv("HOME"); |
9ec6895c MD |
165 | if (!home_dir) { |
166 | WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing."); | |
167 | assert(local_apps.allowed == 0); | |
2691221a | 168 | return -ENOENT; |
9ec6895c MD |
169 | } |
170 | local_apps.allowed = 1; | |
1ea11eab | 171 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 172 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
173 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
174 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
175 | return 0; |
176 | } | |
177 | ||
178 | static | |
179 | int register_app_to_sessiond(int socket) | |
180 | { | |
181 | ssize_t ret; | |
182 | struct { | |
e44418f3 MD |
183 | uint32_t major; |
184 | uint32_t minor; | |
2691221a | 185 | pid_t pid; |
5c33bde8 | 186 | pid_t ppid; |
2691221a | 187 | uid_t uid; |
83610856 | 188 | gid_t gid; |
c117fb1b | 189 | uint32_t bits_per_long; |
2629549e | 190 | char name[16]; /* process name */ |
2691221a MD |
191 | } reg_msg; |
192 | ||
e44418f3 MD |
193 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
194 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 195 | reg_msg.pid = getpid(); |
5c33bde8 | 196 | reg_msg.ppid = getppid(); |
2691221a | 197 | reg_msg.uid = getuid(); |
83610856 | 198 | reg_msg.gid = getgid(); |
c117fb1b | 199 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
08114193 | 200 | lttng_ust_getprocname(reg_msg.name); |
2691221a | 201 | |
57773204 | 202 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
203 | if (ret >= 0 && ret != sizeof(reg_msg)) |
204 | return -EIO; | |
205 | return ret; | |
206 | } | |
207 | ||
d9e99d10 | 208 | static |
57773204 | 209 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 210 | { |
9eb62b9c | 211 | ssize_t len; |
d3a492d1 | 212 | |
57773204 | 213 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 214 | switch (len) { |
a4be8962 | 215 | case sizeof(*lur): |
d3a492d1 MD |
216 | DBG("message successfully sent"); |
217 | return 0; | |
7bc53e94 MD |
218 | default: |
219 | if (len == -ECONNRESET) { | |
220 | DBG("remote end closed connection"); | |
d3a492d1 MD |
221 | return 0; |
222 | } | |
7bc53e94 MD |
223 | if (len < 0) |
224 | return len; | |
225 | DBG("incorrect message size: %zd", len); | |
226 | return -EINVAL; | |
d3a492d1 MD |
227 | } |
228 | } | |
229 | ||
230 | static | |
edaa1431 | 231 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
232 | { |
233 | int ret; | |
234 | ||
edaa1431 MD |
235 | if (sock_info->constructor_sem_posted) |
236 | return 0; | |
237 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
238 | if (uatomic_read(&sem_count) <= 0) { |
239 | return 0; | |
240 | } | |
95259bd0 MD |
241 | ret = uatomic_add_return(&sem_count, -1); |
242 | if (ret == 0) { | |
243 | ret = sem_post(&constructor_wait); | |
244 | assert(!ret); | |
245 | } | |
11ff9c7d MD |
246 | return 0; |
247 | } | |
248 | ||
249 | static | |
250 | int handle_message(struct sock_info *sock_info, | |
57773204 | 251 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 252 | { |
1ea11eab | 253 | int ret = 0; |
b61ce3b2 | 254 | const struct lttng_ust_objd_ops *ops; |
57773204 | 255 | struct ustcomm_ust_reply lur; |
193183fb | 256 | int shm_fd, wait_fd; |
ef9ff354 | 257 | union ust_args args; |
40003310 | 258 | ssize_t len; |
1ea11eab | 259 | |
17dfb34b | 260 | ust_lock(); |
1ea11eab | 261 | |
46050b1a MD |
262 | memset(&lur, 0, sizeof(lur)); |
263 | ||
1ea11eab | 264 | if (lttng_ust_comm_should_quit) { |
46050b1a | 265 | ret = -EPERM; |
1ea11eab MD |
266 | goto end; |
267 | } | |
9eb62b9c | 268 | |
46050b1a MD |
269 | ops = objd_ops(lum->handle); |
270 | if (!ops) { | |
271 | ret = -ENOENT; | |
272 | goto end; | |
1ea11eab | 273 | } |
46050b1a MD |
274 | |
275 | switch (lum->cmd) { | |
11ff9c7d MD |
276 | case LTTNG_UST_REGISTER_DONE: |
277 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 278 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
279 | else |
280 | ret = -EINVAL; | |
281 | break; | |
46050b1a MD |
282 | case LTTNG_UST_RELEASE: |
283 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
284 | ret = -EPERM; | |
285 | else | |
d4419b81 | 286 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 | 287 | break; |
2d78951a MD |
288 | case LTTNG_UST_FILTER: |
289 | { | |
290 | /* Receive filter data */ | |
cd54f6d9 | 291 | struct lttng_ust_filter_bytecode *bytecode; |
2d78951a | 292 | |
cd54f6d9 | 293 | if (lum->u.filter.data_size > FILTER_BYTECODE_MAX_LEN) { |
7bc53e94 | 294 | ERR("Filter data size is too large: %u bytes", |
2d78951a MD |
295 | lum->u.filter.data_size); |
296 | ret = -EINVAL; | |
297 | goto error; | |
298 | } | |
2734ca65 | 299 | |
885b1dfd | 300 | if (lum->u.filter.reloc_offset > lum->u.filter.data_size) { |
7bc53e94 | 301 | ERR("Filter reloc offset %u is not within data", |
2734ca65 CB |
302 | lum->u.filter.reloc_offset); |
303 | ret = -EINVAL; | |
304 | goto error; | |
305 | } | |
306 | ||
cd54f6d9 MD |
307 | bytecode = zmalloc(sizeof(*bytecode) + lum->u.filter.data_size); |
308 | if (!bytecode) { | |
309 | ret = -ENOMEM; | |
310 | goto error; | |
311 | } | |
312 | len = ustcomm_recv_unix_sock(sock, bytecode->data, | |
2d78951a MD |
313 | lum->u.filter.data_size); |
314 | switch (len) { | |
315 | case 0: /* orderly shutdown */ | |
316 | ret = 0; | |
cd54f6d9 | 317 | free(bytecode); |
2d78951a | 318 | goto error; |
2d78951a MD |
319 | default: |
320 | if (len == lum->u.filter.data_size) { | |
7bc53e94 | 321 | DBG("filter data received"); |
2d78951a | 322 | break; |
7bc53e94 MD |
323 | } else if (len < 0) { |
324 | DBG("Receive failed from lttng-sessiond with errno %d", (int) -len); | |
325 | if (len == -ECONNRESET) { | |
326 | ERR("%s remote end closed connection", sock_info->name); | |
327 | ret = len; | |
328 | free(bytecode); | |
329 | goto error; | |
330 | } | |
331 | ret = len; | |
332 | goto end; | |
2d78951a | 333 | } else { |
7bc53e94 | 334 | DBG("incorrect filter data message size: %zd", len); |
2d78951a | 335 | ret = -EINVAL; |
cd54f6d9 | 336 | free(bytecode); |
2d78951a MD |
337 | goto end; |
338 | } | |
339 | } | |
cd54f6d9 MD |
340 | bytecode->len = lum->u.filter.data_size; |
341 | bytecode->reloc_offset = lum->u.filter.reloc_offset; | |
cd54f6d9 | 342 | if (ops->cmd) { |
2d78951a | 343 | ret = ops->cmd(lum->handle, lum->cmd, |
cd54f6d9 | 344 | (unsigned long) bytecode, |
2d78951a | 345 | &args); |
cd54f6d9 MD |
346 | if (ret) { |
347 | free(bytecode); | |
348 | } | |
349 | /* don't free bytecode if everything went fine. */ | |
350 | } else { | |
2d78951a | 351 | ret = -ENOSYS; |
cd54f6d9 MD |
352 | free(bytecode); |
353 | } | |
2d78951a MD |
354 | break; |
355 | } | |
d9e99d10 | 356 | default: |
46050b1a MD |
357 | if (ops->cmd) |
358 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
359 | (unsigned long) &lum->u, |
360 | &args); | |
46050b1a MD |
361 | else |
362 | ret = -ENOSYS; | |
363 | break; | |
d9e99d10 | 364 | } |
46050b1a | 365 | |
1ea11eab | 366 | end: |
46050b1a MD |
367 | lur.handle = lum->handle; |
368 | lur.cmd = lum->cmd; | |
369 | lur.ret_val = ret; | |
370 | if (ret >= 0) { | |
7bc53e94 | 371 | lur.ret_code = LTTNG_UST_OK; |
46050b1a | 372 | } else { |
7bc53e94 MD |
373 | /* |
374 | * Use -LTTNG_UST_ERR as wildcard for UST internal | |
375 | * error that are not caused by the transport, except if | |
376 | * we already have a more precise error message to | |
377 | * report. | |
378 | */ | |
379 | if (ret > -LTTNG_UST_ERR) | |
380 | lur.ret_code = -LTTNG_UST_ERR; | |
381 | else | |
382 | lur.ret_code = ret; | |
46050b1a | 383 | } |
e6ea14c5 MD |
384 | if (ret >= 0) { |
385 | switch (lum->cmd) { | |
386 | case LTTNG_UST_STREAM: | |
387 | /* | |
388 | * Special-case reply to send stream info. | |
389 | * Use lum.u output. | |
390 | */ | |
391 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; | |
392 | shm_fd = *args.stream.shm_fd; | |
393 | wait_fd = *args.stream.wait_fd; | |
394 | break; | |
395 | case LTTNG_UST_METADATA: | |
396 | case LTTNG_UST_CHANNEL: | |
397 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; | |
398 | shm_fd = *args.channel.shm_fd; | |
399 | wait_fd = *args.channel.wait_fd; | |
400 | break; | |
401 | case LTTNG_UST_TRACER_VERSION: | |
402 | lur.u.version = lum->u.version; | |
403 | break; | |
404 | case LTTNG_UST_TRACEPOINT_LIST_GET: | |
405 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); | |
406 | break; | |
407 | } | |
381c0f1e | 408 | } |
46050b1a | 409 | ret = send_reply(sock, &lur); |
193183fb | 410 | if (ret < 0) { |
7bc53e94 | 411 | DBG("error sending reply"); |
193183fb MD |
412 | goto error; |
413 | } | |
46050b1a | 414 | |
824f40b8 MD |
415 | if ((lum->cmd == LTTNG_UST_STREAM |
416 | || lum->cmd == LTTNG_UST_CHANNEL | |
417 | || lum->cmd == LTTNG_UST_METADATA) | |
7bc53e94 | 418 | && lur.ret_code == LTTNG_UST_OK) { |
50be2fc4 MD |
419 | int sendret = 0; |
420 | ||
381c0f1e | 421 | /* we also need to send the file descriptors. */ |
57773204 | 422 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 423 | &shm_fd, &shm_fd, |
381c0f1e MD |
424 | 1, sizeof(int)); |
425 | if (ret < 0) { | |
7bc53e94 | 426 | ERR("send shm_fd"); |
50be2fc4 | 427 | sendret = ret; |
381c0f1e | 428 | } |
50be2fc4 MD |
429 | /* |
430 | * The sessiond expects 2 file descriptors, even upon | |
431 | * error. | |
432 | */ | |
57773204 | 433 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 434 | &wait_fd, &wait_fd, |
381c0f1e MD |
435 | 1, sizeof(int)); |
436 | if (ret < 0) { | |
437 | perror("send wait_fd"); | |
438 | goto error; | |
439 | } | |
50be2fc4 MD |
440 | if (sendret) { |
441 | ret = sendret; | |
442 | goto error; | |
443 | } | |
381c0f1e | 444 | } |
40003310 MD |
445 | /* |
446 | * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field | |
447 | * after the reply. | |
448 | */ | |
7bc53e94 | 449 | if (lur.ret_code == LTTNG_UST_OK) { |
40003310 MD |
450 | switch (lum->cmd) { |
451 | case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET: | |
452 | len = ustcomm_send_unix_sock(sock, | |
453 | &args.field_list.entry, | |
454 | sizeof(args.field_list.entry)); | |
7bc53e94 MD |
455 | if (len < 0) { |
456 | ret = len; | |
457 | goto error; | |
458 | } | |
40003310 | 459 | if (len != sizeof(args.field_list.entry)) { |
7bc53e94 | 460 | ret = -EINVAL; |
40003310 MD |
461 | goto error; |
462 | } | |
463 | } | |
464 | } | |
ef9ff354 MD |
465 | /* |
466 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
467 | * sent to the sessiond. We can therefore close those fds. Note |
468 | * that we keep the write side of the wait_fd open, but close | |
469 | * the read side. | |
ef9ff354 | 470 | */ |
7bc53e94 | 471 | if (lur.ret_code == LTTNG_UST_OK) { |
ef9ff354 MD |
472 | switch (lum->cmd) { |
473 | case LTTNG_UST_STREAM: | |
474 | if (shm_fd >= 0) { | |
475 | ret = close(shm_fd); | |
476 | if (ret) { | |
477 | PERROR("Error closing stream shm_fd"); | |
478 | } | |
479 | *args.stream.shm_fd = -1; | |
480 | } | |
481 | if (wait_fd >= 0) { | |
482 | ret = close(wait_fd); | |
483 | if (ret) { | |
484 | PERROR("Error closing stream wait_fd"); | |
485 | } | |
486 | *args.stream.wait_fd = -1; | |
487 | } | |
488 | break; | |
489 | case LTTNG_UST_METADATA: | |
490 | case LTTNG_UST_CHANNEL: | |
491 | if (shm_fd >= 0) { | |
492 | ret = close(shm_fd); | |
493 | if (ret) { | |
494 | PERROR("Error closing channel shm_fd"); | |
495 | } | |
496 | *args.channel.shm_fd = -1; | |
497 | } | |
498 | if (wait_fd >= 0) { | |
499 | ret = close(wait_fd); | |
500 | if (ret) { | |
501 | PERROR("Error closing channel wait_fd"); | |
502 | } | |
503 | *args.channel.wait_fd = -1; | |
504 | } | |
505 | break; | |
506 | } | |
507 | } | |
508 | ||
381c0f1e | 509 | error: |
17dfb34b | 510 | ust_unlock(); |
1ea11eab | 511 | return ret; |
d9e99d10 MD |
512 | } |
513 | ||
46050b1a | 514 | static |
efe0de09 | 515 | void cleanup_sock_info(struct sock_info *sock_info, int exiting) |
46050b1a MD |
516 | { |
517 | int ret; | |
518 | ||
519 | if (sock_info->socket != -1) { | |
e6973a89 | 520 | ret = ustcomm_close_unix_sock(sock_info->socket); |
46050b1a | 521 | if (ret) { |
7fc90dca | 522 | ERR("Error closing apps socket"); |
46050b1a MD |
523 | } |
524 | sock_info->socket = -1; | |
525 | } | |
526 | if (sock_info->root_handle != -1) { | |
d4419b81 | 527 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
528 | if (ret) { |
529 | ERR("Error unref root handle"); | |
530 | } | |
531 | sock_info->root_handle = -1; | |
532 | } | |
318dfea9 | 533 | sock_info->constructor_sem_posted = 0; |
efe0de09 MD |
534 | /* |
535 | * wait_shm_mmap is used by listener threads outside of the | |
536 | * ust lock, so we cannot tear it down ourselves, because we | |
537 | * cannot join on these threads. Leave this task to the OS | |
538 | * process exit. | |
539 | */ | |
540 | if (!exiting && sock_info->wait_shm_mmap) { | |
7fc90dca MD |
541 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); |
542 | if (ret) { | |
543 | ERR("Error unmapping wait shm"); | |
544 | } | |
545 | sock_info->wait_shm_mmap = NULL; | |
546 | } | |
547 | } | |
548 | ||
58d4b2a2 | 549 | /* |
33bbeb90 MD |
550 | * Using fork to set umask in the child process (not multi-thread safe). |
551 | * We deal with the shm_open vs ftruncate race (happening when the | |
552 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
553 | * safety against shm_unlink) by simply letting the mmap fail and | |
554 | * retrying after a few seconds. | |
555 | * For global shm, everybody has rw access to it until the sessiond | |
556 | * starts. | |
58d4b2a2 | 557 | */ |
7fc90dca | 558 | static |
58d4b2a2 | 559 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 560 | { |
7fc90dca | 561 | int wait_shm_fd, ret; |
58d4b2a2 | 562 | pid_t pid; |
44e073f5 | 563 | |
58d4b2a2 | 564 | /* |
33bbeb90 | 565 | * Try to open read-only. |
58d4b2a2 | 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 | goto end; | |
570 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
571 | /* | |
33bbeb90 MD |
572 | * Real-only open did not work, and it's not because the |
573 | * entry was not present. It's a failure that prohibits | |
574 | * using shm. | |
58d4b2a2 | 575 | */ |
7fc90dca | 576 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 577 | goto end; |
7fc90dca MD |
578 | } |
579 | /* | |
58d4b2a2 MD |
580 | * If the open failed because the file did not exist, try |
581 | * creating it ourself. | |
7fc90dca | 582 | */ |
e8508a49 | 583 | lttng_ust_nest_count++; |
58d4b2a2 | 584 | pid = fork(); |
e8508a49 | 585 | lttng_ust_nest_count--; |
58d4b2a2 MD |
586 | if (pid > 0) { |
587 | int status; | |
588 | ||
589 | /* | |
590 | * Parent: wait for child to return, in which case the | |
591 | * shared memory map will have been created. | |
592 | */ | |
593 | pid = wait(&status); | |
b7d3cb32 | 594 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
595 | wait_shm_fd = -1; |
596 | goto end; | |
7fc90dca | 597 | } |
58d4b2a2 MD |
598 | /* |
599 | * Try to open read-only again after creation. | |
600 | */ | |
33bbeb90 | 601 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
602 | if (wait_shm_fd < 0) { |
603 | /* | |
604 | * Real-only open did not work. It's a failure | |
605 | * that prohibits using shm. | |
606 | */ | |
607 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
608 | goto end; | |
609 | } | |
610 | goto end; | |
611 | } else if (pid == 0) { | |
612 | int create_mode; | |
613 | ||
614 | /* Child */ | |
33bbeb90 | 615 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 616 | if (sock_info->global) |
33bbeb90 | 617 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
618 | /* |
619 | * We're alone in a child process, so we can modify the | |
620 | * process-wide umask. | |
621 | */ | |
33bbeb90 | 622 | umask(~create_mode); |
58d4b2a2 | 623 | /* |
33bbeb90 MD |
624 | * Try creating shm (or get rw access). |
625 | * We don't do an exclusive open, because we allow other | |
626 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
627 | */ |
628 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
629 | O_RDWR | O_CREAT, create_mode); | |
630 | if (wait_shm_fd >= 0) { | |
631 | ret = ftruncate(wait_shm_fd, mmap_size); | |
632 | if (ret) { | |
633 | PERROR("ftruncate"); | |
b0c1425d | 634 | _exit(EXIT_FAILURE); |
58d4b2a2 | 635 | } |
b0c1425d | 636 | _exit(EXIT_SUCCESS); |
58d4b2a2 | 637 | } |
33bbeb90 MD |
638 | /* |
639 | * For local shm, we need to have rw access to accept | |
640 | * opening it: this means the local sessiond will be | |
641 | * able to wake us up. For global shm, we open it even | |
642 | * if rw access is not granted, because the root.root | |
643 | * sessiond will be able to override all rights and wake | |
644 | * us up. | |
645 | */ | |
646 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 | 647 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
5d3bc5ed | 648 | _exit(EXIT_FAILURE); |
58d4b2a2 MD |
649 | } |
650 | /* | |
33bbeb90 MD |
651 | * The shm exists, but we cannot open it RW. Report |
652 | * success. | |
58d4b2a2 | 653 | */ |
5d3bc5ed | 654 | _exit(EXIT_SUCCESS); |
58d4b2a2 MD |
655 | } else { |
656 | return -1; | |
7fc90dca | 657 | } |
58d4b2a2 | 658 | end: |
33bbeb90 MD |
659 | if (wait_shm_fd >= 0 && !sock_info->global) { |
660 | struct stat statbuf; | |
661 | ||
662 | /* | |
663 | * Ensure that our user is the owner of the shm file for | |
664 | * local shm. If we do not own the file, it means our | |
665 | * sessiond will not have access to wake us up (there is | |
666 | * probably a rogue process trying to fake our | |
667 | * sessiond). Fallback to polling method in this case. | |
668 | */ | |
669 | ret = fstat(wait_shm_fd, &statbuf); | |
670 | if (ret) { | |
671 | PERROR("fstat"); | |
672 | goto error_close; | |
673 | } | |
674 | if (statbuf.st_uid != getuid()) | |
675 | goto error_close; | |
676 | } | |
58d4b2a2 | 677 | return wait_shm_fd; |
33bbeb90 MD |
678 | |
679 | error_close: | |
680 | ret = close(wait_shm_fd); | |
681 | if (ret) { | |
682 | PERROR("Error closing fd"); | |
683 | } | |
684 | return -1; | |
58d4b2a2 MD |
685 | } |
686 | ||
687 | static | |
688 | char *get_map_shm(struct sock_info *sock_info) | |
689 | { | |
690 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
691 | int wait_shm_fd, ret; | |
692 | char *wait_shm_mmap; | |
693 | ||
694 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
695 | if (wait_shm_fd < 0) { | |
696 | goto error; | |
44e073f5 | 697 | } |
7fc90dca MD |
698 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
699 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
700 | /* close shm fd immediately after taking the mmap reference */ |
701 | ret = close(wait_shm_fd); | |
702 | if (ret) { | |
33bbeb90 MD |
703 | PERROR("Error closing fd"); |
704 | } | |
705 | if (wait_shm_mmap == MAP_FAILED) { | |
706 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
707 | goto error; | |
7fc90dca MD |
708 | } |
709 | return wait_shm_mmap; | |
710 | ||
711 | error: | |
712 | return NULL; | |
713 | } | |
714 | ||
715 | static | |
716 | void wait_for_sessiond(struct sock_info *sock_info) | |
717 | { | |
efe0de09 | 718 | int ret; |
80e2814b | 719 | |
7fc90dca MD |
720 | ust_lock(); |
721 | if (lttng_ust_comm_should_quit) { | |
722 | goto quit; | |
723 | } | |
37ed587a MD |
724 | if (wait_poll_fallback) { |
725 | goto error; | |
726 | } | |
7fc90dca MD |
727 | if (!sock_info->wait_shm_mmap) { |
728 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
729 | if (!sock_info->wait_shm_mmap) | |
730 | goto error; | |
731 | } | |
732 | ust_unlock(); | |
733 | ||
734 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
735 | /* Wait for futex wakeup */ |
736 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
737 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
738 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 739 | if (ret < 0) { |
37ed587a MD |
740 | if (errno == EFAULT) { |
741 | wait_poll_fallback = 1; | |
a8b870ad | 742 | DBG( |
37ed587a MD |
743 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
744 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
745 | "Please upgrade your kernel " | |
746 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
747 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
748 | if (ust_debug()) |
749 | PERROR("futex"); | |
37ed587a | 750 | } |
80e2814b MD |
751 | } |
752 | } | |
7fc90dca MD |
753 | return; |
754 | ||
755 | quit: | |
756 | ust_unlock(); | |
757 | return; | |
758 | ||
759 | error: | |
760 | ust_unlock(); | |
7fc90dca | 761 | return; |
46050b1a MD |
762 | } |
763 | ||
1ea11eab MD |
764 | /* |
765 | * This thread does not allocate any resource, except within | |
766 | * handle_message, within mutex protection. This mutex protects against | |
767 | * fork and exit. | |
98bf993f | 768 | * The other moment it allocates resources is at socket connection, which |
1ea11eab MD |
769 | * is also protected by the mutex. |
770 | */ | |
d9e99d10 MD |
771 | static |
772 | void *ust_listener_thread(void *arg) | |
773 | { | |
1ea11eab | 774 | struct sock_info *sock_info = arg; |
c0eedf81 | 775 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 776 | |
9eb62b9c MD |
777 | /* Restart trying to connect to the session daemon */ |
778 | restart: | |
c0eedf81 MD |
779 | if (prev_connect_failed) { |
780 | /* Wait for sessiond availability with pipe */ | |
781 | wait_for_sessiond(sock_info); | |
782 | if (has_waited) { | |
783 | has_waited = 0; | |
784 | /* | |
785 | * Sleep for 5 seconds before retrying after a | |
786 | * sequence of failure / wait / failure. This | |
787 | * deals with a killed or broken session daemon. | |
788 | */ | |
789 | sleep(5); | |
790 | } | |
791 | has_waited = 1; | |
792 | prev_connect_failed = 0; | |
793 | } | |
17dfb34b | 794 | ust_lock(); |
1ea11eab MD |
795 | |
796 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 797 | ust_unlock(); |
1ea11eab MD |
798 | goto quit; |
799 | } | |
9eb62b9c | 800 | |
1ea11eab | 801 | if (sock_info->socket != -1) { |
e6973a89 | 802 | ret = ustcomm_close_unix_sock(sock_info->socket); |
1ea11eab | 803 | if (ret) { |
11ff9c7d | 804 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
805 | } |
806 | sock_info->socket = -1; | |
807 | } | |
46050b1a | 808 | |
9eb62b9c | 809 | /* Register */ |
57773204 | 810 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 811 | if (ret < 0) { |
4d3c9523 | 812 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 813 | prev_connect_failed = 1; |
11ff9c7d MD |
814 | /* |
815 | * If we cannot find the sessiond daemon, don't delay | |
816 | * constructor execution. | |
817 | */ | |
edaa1431 | 818 | ret = handle_register_done(sock_info); |
11ff9c7d | 819 | assert(!ret); |
17dfb34b | 820 | ust_unlock(); |
1ea11eab | 821 | goto restart; |
46050b1a MD |
822 | } |
823 | ||
824 | sock_info->socket = sock = ret; | |
825 | ||
826 | /* | |
827 | * Create only one root handle per listener thread for the whole | |
828 | * process lifetime. | |
829 | */ | |
830 | if (sock_info->root_handle == -1) { | |
831 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 832 | if (ret < 0) { |
46050b1a | 833 | ERR("Error creating root handle"); |
17dfb34b | 834 | ust_unlock(); |
46050b1a MD |
835 | goto quit; |
836 | } | |
837 | sock_info->root_handle = ret; | |
9eb62b9c | 838 | } |
1ea11eab | 839 | |
9eb62b9c MD |
840 | ret = register_app_to_sessiond(sock); |
841 | if (ret < 0) { | |
11ff9c7d | 842 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 843 | prev_connect_failed = 1; |
11ff9c7d MD |
844 | /* |
845 | * If we cannot register to the sessiond daemon, don't | |
846 | * delay constructor execution. | |
847 | */ | |
edaa1431 | 848 | ret = handle_register_done(sock_info); |
11ff9c7d | 849 | assert(!ret); |
17dfb34b | 850 | ust_unlock(); |
9eb62b9c MD |
851 | goto restart; |
852 | } | |
17dfb34b | 853 | ust_unlock(); |
46050b1a | 854 | |
d9e99d10 MD |
855 | for (;;) { |
856 | ssize_t len; | |
57773204 | 857 | struct ustcomm_ust_msg lum; |
d9e99d10 | 858 | |
57773204 | 859 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
860 | switch (len) { |
861 | case 0: /* orderly shutdown */ | |
7bc53e94 | 862 | DBG("%s ltt-sessiond has performed an orderly shutdown", sock_info->name); |
8236ba10 MD |
863 | ust_lock(); |
864 | /* | |
865 | * Either sessiond has shutdown or refused us by closing the socket. | |
866 | * In either case, we don't want to delay construction execution, | |
867 | * and we need to wait before retry. | |
868 | */ | |
869 | prev_connect_failed = 1; | |
870 | /* | |
871 | * If we cannot register to the sessiond daemon, don't | |
872 | * delay constructor execution. | |
873 | */ | |
874 | ret = handle_register_done(sock_info); | |
875 | assert(!ret); | |
876 | ust_unlock(); | |
d9e99d10 | 877 | goto end; |
e7723462 | 878 | case sizeof(lum): |
7bc53e94 | 879 | DBG("message received"); |
11ff9c7d | 880 | ret = handle_message(sock_info, sock, &lum); |
7bc53e94 | 881 | if (ret) { |
11ff9c7d | 882 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
883 | } |
884 | continue; | |
7bc53e94 MD |
885 | default: |
886 | if (len < 0) { | |
887 | DBG("Receive failed from lttng-sessiond with errno %d", (int) -len); | |
888 | } else { | |
889 | DBG("incorrect message size (%s socket): %zd", sock_info->name, len); | |
890 | } | |
891 | if (len == -ECONNRESET) { | |
892 | DBG("%s remote end closed connection", sock_info->name); | |
d9e99d10 MD |
893 | goto end; |
894 | } | |
895 | goto end; | |
d9e99d10 MD |
896 | } |
897 | ||
898 | } | |
899 | end: | |
9eb62b9c | 900 | goto restart; /* try to reconnect */ |
1ea11eab | 901 | quit: |
d9e99d10 MD |
902 | return NULL; |
903 | } | |
904 | ||
cf12a773 MD |
905 | /* |
906 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
907 | */ | |
11ff9c7d MD |
908 | static |
909 | int get_timeout(struct timespec *constructor_timeout) | |
910 | { | |
cf12a773 MD |
911 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
912 | char *str_delay; | |
11ff9c7d MD |
913 | int ret; |
914 | ||
69400ac4 | 915 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
916 | if (str_delay) { |
917 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
918 | } | |
919 | ||
920 | switch (constructor_delay_ms) { | |
921 | case -1:/* fall-through */ | |
922 | case 0: | |
923 | return constructor_delay_ms; | |
924 | default: | |
925 | break; | |
926 | } | |
927 | ||
928 | /* | |
929 | * If we are unable to find the current time, don't wait. | |
930 | */ | |
931 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
932 | if (ret) { | |
933 | return -1; | |
934 | } | |
95259bd0 MD |
935 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
936 | constructor_timeout->tv_nsec += | |
937 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
938 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
939 | constructor_timeout->tv_sec++; | |
940 | constructor_timeout->tv_nsec -= 1000000000UL; | |
941 | } | |
cf12a773 | 942 | return 1; |
11ff9c7d | 943 | } |
d9e99d10 | 944 | |
2691221a MD |
945 | /* |
946 | * sessiond monitoring thread: monitor presence of global and per-user | |
947 | * sessiond by polling the application common named pipe. | |
948 | */ | |
edaa1431 | 949 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 950 | { |
11ff9c7d | 951 | struct timespec constructor_timeout; |
ae6a58bf | 952 | sigset_t sig_all_blocked, orig_parent_mask; |
1879f67f | 953 | pthread_attr_t thread_attr; |
cf12a773 | 954 | int timeout_mode; |
2691221a MD |
955 | int ret; |
956 | ||
edaa1431 MD |
957 | if (uatomic_xchg(&initialized, 1) == 1) |
958 | return; | |
959 | ||
eddd8d5d MD |
960 | /* |
961 | * Fixup interdependency between TLS fixup mutex (which happens | |
962 | * to be the dynamic linker mutex) and ust_lock, taken within | |
963 | * the ust lock. | |
964 | */ | |
965 | lttng_fixup_event_tls(); | |
f645cfa7 | 966 | lttng_fixup_ringbuffer_tls(); |
4158a15a | 967 | lttng_fixup_vtid_tls(); |
a903623f | 968 | lttng_fixup_nest_count_tls(); |
009745db | 969 | lttng_fixup_procname_tls(); |
eddd8d5d | 970 | |
edaa1431 MD |
971 | /* |
972 | * We want precise control over the order in which we construct | |
973 | * our sub-libraries vs starting to receive commands from | |
974 | * sessiond (otherwise leading to errors when trying to create | |
975 | * sessiond before the init functions are completed). | |
976 | */ | |
2691221a | 977 | init_usterr(); |
edaa1431 MD |
978 | init_tracepoint(); |
979 | ltt_ring_buffer_metadata_client_init(); | |
980 | ltt_ring_buffer_client_overwrite_init(); | |
981 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 982 | |
cf12a773 | 983 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 984 | |
95259bd0 | 985 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
986 | assert(!ret); |
987 | ||
8d20bf54 | 988 | ret = setup_local_apps(); |
2691221a | 989 | if (ret) { |
9ec6895c | 990 | DBG("local apps setup returned %d", ret); |
2691221a | 991 | } |
ae6a58bf WP |
992 | |
993 | /* A new thread created by pthread_create inherits the signal mask | |
994 | * from the parent. To avoid any signal being received by the | |
995 | * listener thread, we block all signals temporarily in the parent, | |
996 | * while we create the listener thread. | |
997 | */ | |
998 | sigfillset(&sig_all_blocked); | |
999 | ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask); | |
1000 | if (ret) { | |
d94d802c | 1001 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
1002 | } |
1003 | ||
1879f67f MG |
1004 | ret = pthread_attr_init(&thread_attr); |
1005 | if (ret) { | |
1006 | ERR("pthread_attr_init: %s", strerror(ret)); | |
1007 | } | |
1008 | ret = pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED); | |
1009 | if (ret) { | |
1010 | ERR("pthread_attr_setdetachstate: %s", strerror(ret)); | |
1011 | } | |
1012 | ||
1013 | ret = pthread_create(&global_apps.ust_listener, &thread_attr, | |
dde70ea0 | 1014 | ust_listener_thread, &global_apps); |
d94d802c MD |
1015 | if (ret) { |
1016 | ERR("pthread_create global: %s", strerror(ret)); | |
1017 | } | |
8d20bf54 | 1018 | if (local_apps.allowed) { |
1879f67f | 1019 | ret = pthread_create(&local_apps.ust_listener, &thread_attr, |
dde70ea0 | 1020 | ust_listener_thread, &local_apps); |
d94d802c MD |
1021 | if (ret) { |
1022 | ERR("pthread_create local: %s", strerror(ret)); | |
1023 | } | |
8d20bf54 MD |
1024 | } else { |
1025 | handle_register_done(&local_apps); | |
1026 | } | |
1879f67f MG |
1027 | ret = pthread_attr_destroy(&thread_attr); |
1028 | if (ret) { | |
1029 | ERR("pthread_attr_destroy: %s", strerror(ret)); | |
1030 | } | |
8d20bf54 | 1031 | |
ae6a58bf WP |
1032 | /* Restore original signal mask in parent */ |
1033 | ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL); | |
1034 | if (ret) { | |
d94d802c | 1035 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
1036 | } |
1037 | ||
cf12a773 MD |
1038 | switch (timeout_mode) { |
1039 | case 1: /* timeout wait */ | |
95259bd0 MD |
1040 | do { |
1041 | ret = sem_timedwait(&constructor_wait, | |
1042 | &constructor_timeout); | |
1043 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
1044 | if (ret < 0 && errno == ETIMEDOUT) { |
1045 | ERR("Timed out waiting for ltt-sessiond"); | |
1046 | } else { | |
1047 | assert(!ret); | |
1048 | } | |
1049 | break; | |
7b766b16 | 1050 | case -1:/* wait forever */ |
95259bd0 MD |
1051 | do { |
1052 | ret = sem_wait(&constructor_wait); | |
1053 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 1054 | assert(!ret); |
cf12a773 | 1055 | break; |
7b766b16 | 1056 | case 0: /* no timeout */ |
cf12a773 | 1057 | break; |
11ff9c7d | 1058 | } |
2691221a MD |
1059 | } |
1060 | ||
17dfb34b MD |
1061 | static |
1062 | void lttng_ust_cleanup(int exiting) | |
1063 | { | |
efe0de09 | 1064 | cleanup_sock_info(&global_apps, exiting); |
17dfb34b | 1065 | if (local_apps.allowed) { |
efe0de09 | 1066 | cleanup_sock_info(&local_apps, exiting); |
17dfb34b | 1067 | } |
efe0de09 MD |
1068 | /* |
1069 | * The teardown in this function all affect data structures | |
1070 | * accessed under the UST lock by the listener thread. This | |
1071 | * lock, along with the lttng_ust_comm_should_quit flag, ensure | |
1072 | * that none of these threads are accessing this data at this | |
1073 | * point. | |
1074 | */ | |
17dfb34b | 1075 | lttng_ust_abi_exit(); |
003fedf4 | 1076 | lttng_ust_events_exit(); |
17dfb34b MD |
1077 | ltt_ring_buffer_client_discard_exit(); |
1078 | ltt_ring_buffer_client_overwrite_exit(); | |
1079 | ltt_ring_buffer_metadata_client_exit(); | |
1080 | exit_tracepoint(); | |
1081 | if (!exiting) { | |
1082 | /* Reinitialize values for fork */ | |
1083 | sem_count = 2; | |
1084 | lttng_ust_comm_should_quit = 0; | |
1085 | initialized = 0; | |
1086 | } | |
1087 | } | |
1088 | ||
edaa1431 | 1089 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
1090 | { |
1091 | int ret; | |
1092 | ||
9eb62b9c MD |
1093 | /* |
1094 | * Using pthread_cancel here because: | |
1095 | * A) we don't want to hang application teardown. | |
1096 | * B) the thread is not allocating any resource. | |
1097 | */ | |
1ea11eab MD |
1098 | |
1099 | /* | |
1100 | * Require the communication thread to quit. Synchronize with | |
1101 | * mutexes to ensure it is not in a mutex critical section when | |
1102 | * pthread_cancel is later called. | |
1103 | */ | |
17dfb34b | 1104 | ust_lock(); |
1ea11eab | 1105 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 1106 | ust_unlock(); |
1ea11eab | 1107 | |
f5f94532 | 1108 | /* cancel threads */ |
1ea11eab | 1109 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c | 1110 | if (ret) { |
d94d802c MD |
1111 | ERR("Error cancelling global ust listener thread: %s", |
1112 | strerror(ret)); | |
2691221a | 1113 | } |
8d20bf54 MD |
1114 | if (local_apps.allowed) { |
1115 | ret = pthread_cancel(local_apps.ust_listener); | |
1116 | if (ret) { | |
d94d802c MD |
1117 | ERR("Error cancelling local ust listener thread: %s", |
1118 | strerror(ret)); | |
8d20bf54 | 1119 | } |
8d20bf54 | 1120 | } |
efe0de09 MD |
1121 | /* |
1122 | * Do NOT join threads: use of sys_futex makes it impossible to | |
1123 | * join the threads without using async-cancel, but async-cancel | |
1124 | * is delivered by a signal, which could hit the target thread | |
1125 | * anywhere in its code path, including while the ust_lock() is | |
1126 | * held, causing a deadlock for the other thread. Let the OS | |
1127 | * cleanup the threads if there are stalled in a syscall. | |
1128 | */ | |
17dfb34b | 1129 | lttng_ust_cleanup(1); |
2691221a | 1130 | } |
e822f505 MD |
1131 | |
1132 | /* | |
1133 | * We exclude the worker threads across fork and clone (except | |
1134 | * CLONE_VM), because these system calls only keep the forking thread | |
1135 | * running in the child. Therefore, we don't want to call fork or clone | |
1136 | * in the middle of an tracepoint or ust tracing state modification. | |
1137 | * Holding this mutex protects these structures across fork and clone. | |
1138 | */ | |
b728d87e | 1139 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
1140 | { |
1141 | /* | |
1142 | * Disable signals. This is to avoid that the child intervenes | |
1143 | * before it is properly setup for tracing. It is safer to | |
1144 | * disable all signals, because then we know we are not breaking | |
1145 | * anything by restoring the original mask. | |
1146 | */ | |
1147 | sigset_t all_sigs; | |
1148 | int ret; | |
1149 | ||
e8508a49 MD |
1150 | if (lttng_ust_nest_count) |
1151 | return; | |
e822f505 MD |
1152 | /* Disable signals */ |
1153 | sigfillset(&all_sigs); | |
b728d87e | 1154 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
1155 | if (ret == -1) { |
1156 | PERROR("sigprocmask"); | |
1157 | } | |
17dfb34b | 1158 | ust_lock(); |
e822f505 MD |
1159 | rcu_bp_before_fork(); |
1160 | } | |
1161 | ||
b728d87e | 1162 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
1163 | { |
1164 | int ret; | |
1165 | ||
17dfb34b MD |
1166 | DBG("process %d", getpid()); |
1167 | ust_unlock(); | |
e822f505 | 1168 | /* Restore signals */ |
23c8854a | 1169 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
1170 | if (ret == -1) { |
1171 | PERROR("sigprocmask"); | |
1172 | } | |
1173 | } | |
1174 | ||
b728d87e | 1175 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 1176 | { |
e8508a49 MD |
1177 | if (lttng_ust_nest_count) |
1178 | return; | |
17dfb34b | 1179 | DBG("process %d", getpid()); |
e822f505 MD |
1180 | rcu_bp_after_fork_parent(); |
1181 | /* Release mutexes and reenable signals */ | |
b728d87e | 1182 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
1183 | } |
1184 | ||
17dfb34b MD |
1185 | /* |
1186 | * After fork, in the child, we need to cleanup all the leftover state, | |
1187 | * except the worker thread which already magically disappeared thanks | |
1188 | * to the weird Linux fork semantics. After tyding up, we call | |
1189 | * lttng_ust_init() again to start over as a new PID. | |
1190 | * | |
1191 | * This is meant for forks() that have tracing in the child between the | |
1192 | * fork and following exec call (if there is any). | |
1193 | */ | |
b728d87e | 1194 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 1195 | { |
e8508a49 MD |
1196 | if (lttng_ust_nest_count) |
1197 | return; | |
17dfb34b | 1198 | DBG("process %d", getpid()); |
e822f505 MD |
1199 | /* Release urcu mutexes */ |
1200 | rcu_bp_after_fork_child(); | |
17dfb34b | 1201 | lttng_ust_cleanup(0); |
a93bfc45 | 1202 | lttng_context_vtid_reset(); |
e822f505 | 1203 | /* Release mutexes and reenable signals */ |
b728d87e | 1204 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1205 | lttng_ust_init(); |
e822f505 | 1206 | } |