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> | |
cd54f6d9 | 46 | #include <helper.h> |
44c72f10 | 47 | #include "tracepoint-internal.h" |
b751f722 | 48 | #include "ltt-tracer-core.h" |
08114193 | 49 | #include "compat.h" |
f645cfa7 | 50 | #include "../libringbuffer/tlsfixup.h" |
edaa1431 MD |
51 | |
52 | /* | |
53 | * Has lttng ust comm constructor been called ? | |
54 | */ | |
55 | static int initialized; | |
56 | ||
1ea11eab | 57 | /* |
17dfb34b MD |
58 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
59 | * Held when handling a command, also held by fork() to deal with | |
60 | * removal of threads, and by exit path. | |
1ea11eab | 61 | */ |
1ea11eab MD |
62 | |
63 | /* Should the ust comm thread quit ? */ | |
64 | static int lttng_ust_comm_should_quit; | |
65 | ||
11ff9c7d MD |
66 | /* |
67 | * Wait for either of these before continuing to the main | |
68 | * program: | |
69 | * - the register_done message from sessiond daemon | |
70 | * (will let the sessiond daemon enable sessions before main | |
71 | * starts.) | |
72 | * - sessiond daemon is not reachable. | |
73 | * - timeout (ensuring applications are resilient to session | |
74 | * daemon problems). | |
75 | */ | |
76 | static sem_t constructor_wait; | |
950aab0c MD |
77 | /* |
78 | * Doing this for both the global and local sessiond. | |
79 | */ | |
95259bd0 | 80 | static int sem_count = { 2 }; |
11ff9c7d | 81 | |
e8508a49 MD |
82 | /* |
83 | * Counting nesting within lttng-ust. Used to ensure that calling fork() | |
84 | * from liblttng-ust does not execute the pre/post fork handlers. | |
85 | */ | |
86 | static int __thread lttng_ust_nest_count; | |
87 | ||
1ea11eab MD |
88 | /* |
89 | * Info about socket and associated listener thread. | |
90 | */ | |
91 | struct sock_info { | |
11ff9c7d | 92 | const char *name; |
1ea11eab | 93 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 94 | int root_handle; |
8d20bf54 MD |
95 | int constructor_sem_posted; |
96 | int allowed; | |
44e073f5 | 97 | int global; |
7fc90dca MD |
98 | |
99 | char sock_path[PATH_MAX]; | |
100 | int socket; | |
101 | ||
102 | char wait_shm_path[PATH_MAX]; | |
103 | char *wait_shm_mmap; | |
1ea11eab | 104 | }; |
2691221a MD |
105 | |
106 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 107 | struct sock_info global_apps = { |
11ff9c7d | 108 | .name = "global", |
44e073f5 | 109 | .global = 1, |
7fc90dca | 110 | |
46050b1a | 111 | .root_handle = -1, |
8d20bf54 | 112 | .allowed = 1, |
7fc90dca MD |
113 | |
114 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
115 | .socket = -1, | |
116 | ||
117 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 118 | }; |
2691221a MD |
119 | |
120 | /* TODO: allow global_apps_sock_path override */ | |
121 | ||
1ea11eab | 122 | struct sock_info local_apps = { |
11ff9c7d | 123 | .name = "local", |
44e073f5 | 124 | .global = 0, |
46050b1a | 125 | .root_handle = -1, |
8d20bf54 | 126 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
127 | |
128 | .socket = -1, | |
1ea11eab | 129 | }; |
2691221a | 130 | |
37ed587a MD |
131 | static int wait_poll_fallback; |
132 | ||
edaa1431 MD |
133 | extern void ltt_ring_buffer_client_overwrite_init(void); |
134 | extern void ltt_ring_buffer_client_discard_init(void); | |
135 | extern void ltt_ring_buffer_metadata_client_init(void); | |
136 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
137 | extern void ltt_ring_buffer_client_discard_exit(void); | |
138 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
139 | ||
a903623f MD |
140 | /* |
141 | * Force a read (imply TLS fixup for dlopen) of TLS variables. | |
142 | */ | |
143 | static | |
144 | void lttng_fixup_nest_count_tls(void) | |
145 | { | |
146 | asm volatile ("" : : "m" (lttng_ust_nest_count)); | |
147 | } | |
148 | ||
2691221a | 149 | static |
8d20bf54 | 150 | int setup_local_apps(void) |
2691221a MD |
151 | { |
152 | const char *home_dir; | |
7fc90dca | 153 | uid_t uid; |
2691221a | 154 | |
7fc90dca | 155 | uid = getuid(); |
8d20bf54 MD |
156 | /* |
157 | * Disallow per-user tracing for setuid binaries. | |
158 | */ | |
7fc90dca | 159 | if (uid != geteuid()) { |
9ec6895c | 160 | assert(local_apps.allowed == 0); |
d0a1ae63 | 161 | return 0; |
8d20bf54 | 162 | } |
2691221a | 163 | home_dir = (const char *) getenv("HOME"); |
9ec6895c MD |
164 | if (!home_dir) { |
165 | WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing."); | |
166 | assert(local_apps.allowed == 0); | |
2691221a | 167 | return -ENOENT; |
9ec6895c MD |
168 | } |
169 | local_apps.allowed = 1; | |
1ea11eab | 170 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 171 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
172 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
173 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
174 | return 0; |
175 | } | |
176 | ||
177 | static | |
178 | int register_app_to_sessiond(int socket) | |
179 | { | |
180 | ssize_t ret; | |
181 | struct { | |
e44418f3 MD |
182 | uint32_t major; |
183 | uint32_t minor; | |
2691221a | 184 | pid_t pid; |
5c33bde8 | 185 | pid_t ppid; |
2691221a | 186 | uid_t uid; |
83610856 | 187 | gid_t gid; |
c117fb1b | 188 | uint32_t bits_per_long; |
2629549e | 189 | char name[16]; /* process name */ |
2691221a MD |
190 | } reg_msg; |
191 | ||
e44418f3 MD |
192 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
193 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 194 | reg_msg.pid = getpid(); |
5c33bde8 | 195 | reg_msg.ppid = getppid(); |
2691221a | 196 | reg_msg.uid = getuid(); |
83610856 | 197 | reg_msg.gid = getgid(); |
c117fb1b | 198 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
08114193 | 199 | lttng_ust_getprocname(reg_msg.name); |
2691221a | 200 | |
57773204 | 201 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
202 | if (ret >= 0 && ret != sizeof(reg_msg)) |
203 | return -EIO; | |
204 | return ret; | |
205 | } | |
206 | ||
d9e99d10 | 207 | static |
57773204 | 208 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 209 | { |
9eb62b9c | 210 | ssize_t len; |
d3a492d1 | 211 | |
57773204 | 212 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 213 | switch (len) { |
a4be8962 | 214 | case sizeof(*lur): |
d3a492d1 MD |
215 | DBG("message successfully sent"); |
216 | return 0; | |
217 | case -1: | |
218 | if (errno == ECONNRESET) { | |
219 | printf("remote end closed connection\n"); | |
220 | return 0; | |
221 | } | |
222 | return -1; | |
223 | default: | |
224 | printf("incorrect message size: %zd\n", len); | |
225 | return -1; | |
226 | } | |
227 | } | |
228 | ||
229 | static | |
edaa1431 | 230 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
231 | { |
232 | int ret; | |
233 | ||
edaa1431 MD |
234 | if (sock_info->constructor_sem_posted) |
235 | return 0; | |
236 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
237 | if (uatomic_read(&sem_count) <= 0) { |
238 | return 0; | |
239 | } | |
95259bd0 MD |
240 | ret = uatomic_add_return(&sem_count, -1); |
241 | if (ret == 0) { | |
242 | ret = sem_post(&constructor_wait); | |
243 | assert(!ret); | |
244 | } | |
11ff9c7d MD |
245 | return 0; |
246 | } | |
247 | ||
248 | static | |
249 | int handle_message(struct sock_info *sock_info, | |
57773204 | 250 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 251 | { |
1ea11eab | 252 | int ret = 0; |
b61ce3b2 | 253 | const struct lttng_ust_objd_ops *ops; |
57773204 | 254 | struct ustcomm_ust_reply lur; |
193183fb | 255 | int shm_fd, wait_fd; |
ef9ff354 | 256 | union ust_args args; |
40003310 | 257 | ssize_t len; |
1ea11eab | 258 | |
17dfb34b | 259 | ust_lock(); |
1ea11eab | 260 | |
46050b1a MD |
261 | memset(&lur, 0, sizeof(lur)); |
262 | ||
1ea11eab | 263 | if (lttng_ust_comm_should_quit) { |
46050b1a | 264 | ret = -EPERM; |
1ea11eab MD |
265 | goto end; |
266 | } | |
9eb62b9c | 267 | |
46050b1a MD |
268 | ops = objd_ops(lum->handle); |
269 | if (!ops) { | |
270 | ret = -ENOENT; | |
271 | goto end; | |
1ea11eab | 272 | } |
46050b1a MD |
273 | |
274 | switch (lum->cmd) { | |
11ff9c7d MD |
275 | case LTTNG_UST_REGISTER_DONE: |
276 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 277 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
278 | else |
279 | ret = -EINVAL; | |
280 | break; | |
46050b1a MD |
281 | case LTTNG_UST_RELEASE: |
282 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
283 | ret = -EPERM; | |
284 | else | |
d4419b81 | 285 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 | 286 | break; |
2d78951a MD |
287 | case LTTNG_UST_FILTER: |
288 | { | |
289 | /* Receive filter data */ | |
cd54f6d9 | 290 | struct lttng_ust_filter_bytecode *bytecode; |
2d78951a | 291 | |
cd54f6d9 | 292 | if (lum->u.filter.data_size > FILTER_BYTECODE_MAX_LEN) { |
2d78951a MD |
293 | ERR("Filter data size is too large: %u bytes\n", |
294 | lum->u.filter.data_size); | |
295 | ret = -EINVAL; | |
296 | goto error; | |
297 | } | |
2734ca65 | 298 | |
885b1dfd | 299 | if (lum->u.filter.reloc_offset > lum->u.filter.data_size) { |
2734ca65 CB |
300 | ERR("Filter reloc offset %u is not within data\n", |
301 | lum->u.filter.reloc_offset); | |
302 | ret = -EINVAL; | |
303 | goto error; | |
304 | } | |
305 | ||
cd54f6d9 MD |
306 | bytecode = zmalloc(sizeof(*bytecode) + lum->u.filter.data_size); |
307 | if (!bytecode) { | |
308 | ret = -ENOMEM; | |
309 | goto error; | |
310 | } | |
311 | len = ustcomm_recv_unix_sock(sock, bytecode->data, | |
2d78951a MD |
312 | lum->u.filter.data_size); |
313 | switch (len) { | |
314 | case 0: /* orderly shutdown */ | |
315 | ret = 0; | |
cd54f6d9 | 316 | free(bytecode); |
2d78951a MD |
317 | goto error; |
318 | case -1: | |
319 | DBG("Receive failed from lttng-sessiond with errno %d", errno); | |
320 | if (errno == ECONNRESET) { | |
321 | ERR("%s remote end closed connection\n", sock_info->name); | |
322 | ret = -EINVAL; | |
cd54f6d9 | 323 | free(bytecode); |
2d78951a MD |
324 | goto error; |
325 | } | |
326 | ret = -EINVAL; | |
327 | goto end; | |
328 | default: | |
329 | if (len == lum->u.filter.data_size) { | |
330 | DBG("filter data received\n"); | |
331 | break; | |
332 | } else { | |
333 | ERR("incorrect filter data message size: %zd\n", len); | |
334 | ret = -EINVAL; | |
cd54f6d9 | 335 | free(bytecode); |
2d78951a MD |
336 | goto end; |
337 | } | |
338 | } | |
cd54f6d9 MD |
339 | bytecode->len = lum->u.filter.data_size; |
340 | bytecode->reloc_offset = lum->u.filter.reloc_offset; | |
cd54f6d9 | 341 | if (ops->cmd) { |
2d78951a | 342 | ret = ops->cmd(lum->handle, lum->cmd, |
cd54f6d9 | 343 | (unsigned long) bytecode, |
2d78951a | 344 | &args); |
cd54f6d9 MD |
345 | if (ret) { |
346 | free(bytecode); | |
347 | } | |
348 | /* don't free bytecode if everything went fine. */ | |
349 | } else { | |
2d78951a | 350 | ret = -ENOSYS; |
cd54f6d9 MD |
351 | free(bytecode); |
352 | } | |
2d78951a MD |
353 | break; |
354 | } | |
d9e99d10 | 355 | default: |
46050b1a MD |
356 | if (ops->cmd) |
357 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
358 | (unsigned long) &lum->u, |
359 | &args); | |
46050b1a MD |
360 | else |
361 | ret = -ENOSYS; | |
362 | break; | |
d9e99d10 | 363 | } |
46050b1a | 364 | |
1ea11eab | 365 | end: |
46050b1a MD |
366 | lur.handle = lum->handle; |
367 | lur.cmd = lum->cmd; | |
368 | lur.ret_val = ret; | |
369 | if (ret >= 0) { | |
57773204 | 370 | lur.ret_code = USTCOMM_OK; |
46050b1a | 371 | } else { |
57773204 | 372 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 373 | lur.ret_code = ret; |
46050b1a | 374 | } |
e6ea14c5 MD |
375 | if (ret >= 0) { |
376 | switch (lum->cmd) { | |
377 | case LTTNG_UST_STREAM: | |
378 | /* | |
379 | * Special-case reply to send stream info. | |
380 | * Use lum.u output. | |
381 | */ | |
382 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; | |
383 | shm_fd = *args.stream.shm_fd; | |
384 | wait_fd = *args.stream.wait_fd; | |
385 | break; | |
386 | case LTTNG_UST_METADATA: | |
387 | case LTTNG_UST_CHANNEL: | |
388 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; | |
389 | shm_fd = *args.channel.shm_fd; | |
390 | wait_fd = *args.channel.wait_fd; | |
391 | break; | |
392 | case LTTNG_UST_TRACER_VERSION: | |
393 | lur.u.version = lum->u.version; | |
394 | break; | |
395 | case LTTNG_UST_TRACEPOINT_LIST_GET: | |
396 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); | |
397 | break; | |
398 | } | |
381c0f1e | 399 | } |
46050b1a | 400 | ret = send_reply(sock, &lur); |
193183fb MD |
401 | if (ret < 0) { |
402 | perror("error sending reply"); | |
403 | goto error; | |
404 | } | |
46050b1a | 405 | |
824f40b8 MD |
406 | if ((lum->cmd == LTTNG_UST_STREAM |
407 | || lum->cmd == LTTNG_UST_CHANNEL | |
408 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 409 | && lur.ret_code == USTCOMM_OK) { |
50be2fc4 MD |
410 | int sendret = 0; |
411 | ||
381c0f1e | 412 | /* we also need to send the file descriptors. */ |
57773204 | 413 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 414 | &shm_fd, &shm_fd, |
381c0f1e MD |
415 | 1, sizeof(int)); |
416 | if (ret < 0) { | |
417 | perror("send shm_fd"); | |
50be2fc4 | 418 | sendret = ret; |
381c0f1e | 419 | } |
50be2fc4 MD |
420 | /* |
421 | * The sessiond expects 2 file descriptors, even upon | |
422 | * error. | |
423 | */ | |
57773204 | 424 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 425 | &wait_fd, &wait_fd, |
381c0f1e MD |
426 | 1, sizeof(int)); |
427 | if (ret < 0) { | |
428 | perror("send wait_fd"); | |
429 | goto error; | |
430 | } | |
50be2fc4 MD |
431 | if (sendret) { |
432 | ret = sendret; | |
433 | goto error; | |
434 | } | |
381c0f1e | 435 | } |
40003310 MD |
436 | /* |
437 | * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field | |
438 | * after the reply. | |
439 | */ | |
440 | if (lur.ret_code == USTCOMM_OK) { | |
441 | switch (lum->cmd) { | |
442 | case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET: | |
443 | len = ustcomm_send_unix_sock(sock, | |
444 | &args.field_list.entry, | |
445 | sizeof(args.field_list.entry)); | |
446 | if (len != sizeof(args.field_list.entry)) { | |
447 | ret = -1; | |
448 | goto error; | |
449 | } | |
450 | } | |
451 | } | |
ef9ff354 MD |
452 | /* |
453 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
454 | * sent to the sessiond. We can therefore close those fds. Note |
455 | * that we keep the write side of the wait_fd open, but close | |
456 | * the read side. | |
ef9ff354 MD |
457 | */ |
458 | if (lur.ret_code == USTCOMM_OK) { | |
459 | switch (lum->cmd) { | |
460 | case LTTNG_UST_STREAM: | |
461 | if (shm_fd >= 0) { | |
462 | ret = close(shm_fd); | |
463 | if (ret) { | |
464 | PERROR("Error closing stream shm_fd"); | |
465 | } | |
466 | *args.stream.shm_fd = -1; | |
467 | } | |
468 | if (wait_fd >= 0) { | |
469 | ret = close(wait_fd); | |
470 | if (ret) { | |
471 | PERROR("Error closing stream wait_fd"); | |
472 | } | |
473 | *args.stream.wait_fd = -1; | |
474 | } | |
475 | break; | |
476 | case LTTNG_UST_METADATA: | |
477 | case LTTNG_UST_CHANNEL: | |
478 | if (shm_fd >= 0) { | |
479 | ret = close(shm_fd); | |
480 | if (ret) { | |
481 | PERROR("Error closing channel shm_fd"); | |
482 | } | |
483 | *args.channel.shm_fd = -1; | |
484 | } | |
485 | if (wait_fd >= 0) { | |
486 | ret = close(wait_fd); | |
487 | if (ret) { | |
488 | PERROR("Error closing channel wait_fd"); | |
489 | } | |
490 | *args.channel.wait_fd = -1; | |
491 | } | |
492 | break; | |
493 | } | |
494 | } | |
495 | ||
381c0f1e | 496 | error: |
17dfb34b | 497 | ust_unlock(); |
1ea11eab | 498 | return ret; |
d9e99d10 MD |
499 | } |
500 | ||
46050b1a | 501 | static |
efe0de09 | 502 | void cleanup_sock_info(struct sock_info *sock_info, int exiting) |
46050b1a MD |
503 | { |
504 | int ret; | |
505 | ||
506 | if (sock_info->socket != -1) { | |
e6973a89 | 507 | ret = ustcomm_close_unix_sock(sock_info->socket); |
46050b1a | 508 | if (ret) { |
7fc90dca | 509 | ERR("Error closing apps socket"); |
46050b1a MD |
510 | } |
511 | sock_info->socket = -1; | |
512 | } | |
513 | if (sock_info->root_handle != -1) { | |
d4419b81 | 514 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
515 | if (ret) { |
516 | ERR("Error unref root handle"); | |
517 | } | |
518 | sock_info->root_handle = -1; | |
519 | } | |
318dfea9 | 520 | sock_info->constructor_sem_posted = 0; |
efe0de09 MD |
521 | /* |
522 | * wait_shm_mmap is used by listener threads outside of the | |
523 | * ust lock, so we cannot tear it down ourselves, because we | |
524 | * cannot join on these threads. Leave this task to the OS | |
525 | * process exit. | |
526 | */ | |
527 | if (!exiting && sock_info->wait_shm_mmap) { | |
7fc90dca MD |
528 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); |
529 | if (ret) { | |
530 | ERR("Error unmapping wait shm"); | |
531 | } | |
532 | sock_info->wait_shm_mmap = NULL; | |
533 | } | |
534 | } | |
535 | ||
58d4b2a2 | 536 | /* |
33bbeb90 MD |
537 | * Using fork to set umask in the child process (not multi-thread safe). |
538 | * We deal with the shm_open vs ftruncate race (happening when the | |
539 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
540 | * safety against shm_unlink) by simply letting the mmap fail and | |
541 | * retrying after a few seconds. | |
542 | * For global shm, everybody has rw access to it until the sessiond | |
543 | * starts. | |
58d4b2a2 | 544 | */ |
7fc90dca | 545 | static |
58d4b2a2 | 546 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 547 | { |
7fc90dca | 548 | int wait_shm_fd, ret; |
58d4b2a2 | 549 | pid_t pid; |
44e073f5 | 550 | |
58d4b2a2 | 551 | /* |
33bbeb90 | 552 | * Try to open read-only. |
58d4b2a2 | 553 | */ |
33bbeb90 | 554 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
555 | if (wait_shm_fd >= 0) { |
556 | goto end; | |
557 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
558 | /* | |
33bbeb90 MD |
559 | * Real-only open did not work, and it's not because the |
560 | * entry was not present. It's a failure that prohibits | |
561 | * using shm. | |
58d4b2a2 | 562 | */ |
7fc90dca | 563 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 564 | goto end; |
7fc90dca MD |
565 | } |
566 | /* | |
58d4b2a2 MD |
567 | * If the open failed because the file did not exist, try |
568 | * creating it ourself. | |
7fc90dca | 569 | */ |
e8508a49 | 570 | lttng_ust_nest_count++; |
58d4b2a2 | 571 | pid = fork(); |
e8508a49 | 572 | lttng_ust_nest_count--; |
58d4b2a2 MD |
573 | if (pid > 0) { |
574 | int status; | |
575 | ||
576 | /* | |
577 | * Parent: wait for child to return, in which case the | |
578 | * shared memory map will have been created. | |
579 | */ | |
580 | pid = wait(&status); | |
b7d3cb32 | 581 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
582 | wait_shm_fd = -1; |
583 | goto end; | |
7fc90dca | 584 | } |
58d4b2a2 MD |
585 | /* |
586 | * Try to open read-only again after creation. | |
587 | */ | |
33bbeb90 | 588 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
589 | if (wait_shm_fd < 0) { |
590 | /* | |
591 | * Real-only open did not work. It's a failure | |
592 | * that prohibits using shm. | |
593 | */ | |
594 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
595 | goto end; | |
596 | } | |
597 | goto end; | |
598 | } else if (pid == 0) { | |
599 | int create_mode; | |
600 | ||
601 | /* Child */ | |
33bbeb90 | 602 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 603 | if (sock_info->global) |
33bbeb90 | 604 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
605 | /* |
606 | * We're alone in a child process, so we can modify the | |
607 | * process-wide umask. | |
608 | */ | |
33bbeb90 | 609 | umask(~create_mode); |
58d4b2a2 | 610 | /* |
33bbeb90 MD |
611 | * Try creating shm (or get rw access). |
612 | * We don't do an exclusive open, because we allow other | |
613 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
614 | */ |
615 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
616 | O_RDWR | O_CREAT, create_mode); | |
617 | if (wait_shm_fd >= 0) { | |
618 | ret = ftruncate(wait_shm_fd, mmap_size); | |
619 | if (ret) { | |
620 | PERROR("ftruncate"); | |
b0c1425d | 621 | _exit(EXIT_FAILURE); |
58d4b2a2 | 622 | } |
b0c1425d | 623 | _exit(EXIT_SUCCESS); |
58d4b2a2 | 624 | } |
33bbeb90 MD |
625 | /* |
626 | * For local shm, we need to have rw access to accept | |
627 | * opening it: this means the local sessiond will be | |
628 | * able to wake us up. For global shm, we open it even | |
629 | * if rw access is not granted, because the root.root | |
630 | * sessiond will be able to override all rights and wake | |
631 | * us up. | |
632 | */ | |
633 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 | 634 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
5d3bc5ed | 635 | _exit(EXIT_FAILURE); |
58d4b2a2 MD |
636 | } |
637 | /* | |
33bbeb90 MD |
638 | * The shm exists, but we cannot open it RW. Report |
639 | * success. | |
58d4b2a2 | 640 | */ |
5d3bc5ed | 641 | _exit(EXIT_SUCCESS); |
58d4b2a2 MD |
642 | } else { |
643 | return -1; | |
7fc90dca | 644 | } |
58d4b2a2 | 645 | end: |
33bbeb90 MD |
646 | if (wait_shm_fd >= 0 && !sock_info->global) { |
647 | struct stat statbuf; | |
648 | ||
649 | /* | |
650 | * Ensure that our user is the owner of the shm file for | |
651 | * local shm. If we do not own the file, it means our | |
652 | * sessiond will not have access to wake us up (there is | |
653 | * probably a rogue process trying to fake our | |
654 | * sessiond). Fallback to polling method in this case. | |
655 | */ | |
656 | ret = fstat(wait_shm_fd, &statbuf); | |
657 | if (ret) { | |
658 | PERROR("fstat"); | |
659 | goto error_close; | |
660 | } | |
661 | if (statbuf.st_uid != getuid()) | |
662 | goto error_close; | |
663 | } | |
58d4b2a2 | 664 | return wait_shm_fd; |
33bbeb90 MD |
665 | |
666 | error_close: | |
667 | ret = close(wait_shm_fd); | |
668 | if (ret) { | |
669 | PERROR("Error closing fd"); | |
670 | } | |
671 | return -1; | |
58d4b2a2 MD |
672 | } |
673 | ||
674 | static | |
675 | char *get_map_shm(struct sock_info *sock_info) | |
676 | { | |
677 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
678 | int wait_shm_fd, ret; | |
679 | char *wait_shm_mmap; | |
680 | ||
681 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
682 | if (wait_shm_fd < 0) { | |
683 | goto error; | |
44e073f5 | 684 | } |
7fc90dca MD |
685 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
686 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
687 | /* close shm fd immediately after taking the mmap reference */ |
688 | ret = close(wait_shm_fd); | |
689 | if (ret) { | |
33bbeb90 MD |
690 | PERROR("Error closing fd"); |
691 | } | |
692 | if (wait_shm_mmap == MAP_FAILED) { | |
693 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
694 | goto error; | |
7fc90dca MD |
695 | } |
696 | return wait_shm_mmap; | |
697 | ||
698 | error: | |
699 | return NULL; | |
700 | } | |
701 | ||
702 | static | |
703 | void wait_for_sessiond(struct sock_info *sock_info) | |
704 | { | |
efe0de09 | 705 | int ret; |
80e2814b | 706 | |
7fc90dca MD |
707 | ust_lock(); |
708 | if (lttng_ust_comm_should_quit) { | |
709 | goto quit; | |
710 | } | |
37ed587a MD |
711 | if (wait_poll_fallback) { |
712 | goto error; | |
713 | } | |
7fc90dca MD |
714 | if (!sock_info->wait_shm_mmap) { |
715 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
716 | if (!sock_info->wait_shm_mmap) | |
717 | goto error; | |
718 | } | |
719 | ust_unlock(); | |
720 | ||
721 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
722 | /* Wait for futex wakeup */ |
723 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
724 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
725 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 726 | if (ret < 0) { |
37ed587a MD |
727 | if (errno == EFAULT) { |
728 | wait_poll_fallback = 1; | |
a8b870ad | 729 | DBG( |
37ed587a MD |
730 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
731 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
732 | "Please upgrade your kernel " | |
733 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
734 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
735 | if (ust_debug()) |
736 | PERROR("futex"); | |
37ed587a | 737 | } |
80e2814b MD |
738 | } |
739 | } | |
7fc90dca MD |
740 | return; |
741 | ||
742 | quit: | |
743 | ust_unlock(); | |
744 | return; | |
745 | ||
746 | error: | |
747 | ust_unlock(); | |
7fc90dca | 748 | return; |
46050b1a MD |
749 | } |
750 | ||
1ea11eab MD |
751 | /* |
752 | * This thread does not allocate any resource, except within | |
753 | * handle_message, within mutex protection. This mutex protects against | |
754 | * fork and exit. | |
98bf993f | 755 | * The other moment it allocates resources is at socket connection, which |
1ea11eab MD |
756 | * is also protected by the mutex. |
757 | */ | |
d9e99d10 MD |
758 | static |
759 | void *ust_listener_thread(void *arg) | |
760 | { | |
1ea11eab | 761 | struct sock_info *sock_info = arg; |
c0eedf81 | 762 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 763 | |
9eb62b9c MD |
764 | /* Restart trying to connect to the session daemon */ |
765 | restart: | |
c0eedf81 MD |
766 | if (prev_connect_failed) { |
767 | /* Wait for sessiond availability with pipe */ | |
768 | wait_for_sessiond(sock_info); | |
769 | if (has_waited) { | |
770 | has_waited = 0; | |
771 | /* | |
772 | * Sleep for 5 seconds before retrying after a | |
773 | * sequence of failure / wait / failure. This | |
774 | * deals with a killed or broken session daemon. | |
775 | */ | |
776 | sleep(5); | |
777 | } | |
778 | has_waited = 1; | |
779 | prev_connect_failed = 0; | |
780 | } | |
17dfb34b | 781 | ust_lock(); |
1ea11eab MD |
782 | |
783 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 784 | ust_unlock(); |
1ea11eab MD |
785 | goto quit; |
786 | } | |
9eb62b9c | 787 | |
1ea11eab | 788 | if (sock_info->socket != -1) { |
e6973a89 | 789 | ret = ustcomm_close_unix_sock(sock_info->socket); |
1ea11eab | 790 | if (ret) { |
11ff9c7d | 791 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
792 | } |
793 | sock_info->socket = -1; | |
794 | } | |
46050b1a | 795 | |
9eb62b9c | 796 | /* Register */ |
57773204 | 797 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 798 | if (ret < 0) { |
4d3c9523 | 799 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 800 | prev_connect_failed = 1; |
11ff9c7d MD |
801 | /* |
802 | * If we cannot find the sessiond daemon, don't delay | |
803 | * constructor execution. | |
804 | */ | |
edaa1431 | 805 | ret = handle_register_done(sock_info); |
11ff9c7d | 806 | assert(!ret); |
17dfb34b | 807 | ust_unlock(); |
1ea11eab | 808 | goto restart; |
46050b1a MD |
809 | } |
810 | ||
811 | sock_info->socket = sock = ret; | |
812 | ||
813 | /* | |
814 | * Create only one root handle per listener thread for the whole | |
815 | * process lifetime. | |
816 | */ | |
817 | if (sock_info->root_handle == -1) { | |
818 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 819 | if (ret < 0) { |
46050b1a | 820 | ERR("Error creating root handle"); |
17dfb34b | 821 | ust_unlock(); |
46050b1a MD |
822 | goto quit; |
823 | } | |
824 | sock_info->root_handle = ret; | |
9eb62b9c | 825 | } |
1ea11eab | 826 | |
9eb62b9c MD |
827 | ret = register_app_to_sessiond(sock); |
828 | if (ret < 0) { | |
11ff9c7d | 829 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 830 | prev_connect_failed = 1; |
11ff9c7d MD |
831 | /* |
832 | * If we cannot register to the sessiond daemon, don't | |
833 | * delay constructor execution. | |
834 | */ | |
edaa1431 | 835 | ret = handle_register_done(sock_info); |
11ff9c7d | 836 | assert(!ret); |
17dfb34b | 837 | ust_unlock(); |
9eb62b9c MD |
838 | goto restart; |
839 | } | |
17dfb34b | 840 | ust_unlock(); |
46050b1a | 841 | |
d9e99d10 MD |
842 | for (;;) { |
843 | ssize_t len; | |
57773204 | 844 | struct ustcomm_ust_msg lum; |
d9e99d10 | 845 | |
57773204 | 846 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
847 | switch (len) { |
848 | case 0: /* orderly shutdown */ | |
11ff9c7d | 849 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
850 | ust_lock(); |
851 | /* | |
852 | * Either sessiond has shutdown or refused us by closing the socket. | |
853 | * In either case, we don't want to delay construction execution, | |
854 | * and we need to wait before retry. | |
855 | */ | |
856 | prev_connect_failed = 1; | |
857 | /* | |
858 | * If we cannot register to the sessiond daemon, don't | |
859 | * delay constructor execution. | |
860 | */ | |
861 | ret = handle_register_done(sock_info); | |
862 | assert(!ret); | |
863 | ust_unlock(); | |
d9e99d10 | 864 | goto end; |
e7723462 | 865 | case sizeof(lum): |
d9e99d10 | 866 | DBG("message received\n"); |
11ff9c7d | 867 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 868 | if (ret < 0) { |
11ff9c7d | 869 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
870 | } |
871 | continue; | |
872 | case -1: | |
8236ba10 | 873 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 874 | if (errno == ECONNRESET) { |
11ff9c7d | 875 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
876 | goto end; |
877 | } | |
878 | goto end; | |
879 | default: | |
11ff9c7d | 880 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
881 | continue; |
882 | } | |
883 | ||
884 | } | |
885 | end: | |
9eb62b9c | 886 | goto restart; /* try to reconnect */ |
1ea11eab | 887 | quit: |
d9e99d10 MD |
888 | return NULL; |
889 | } | |
890 | ||
cf12a773 MD |
891 | /* |
892 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
893 | */ | |
11ff9c7d MD |
894 | static |
895 | int get_timeout(struct timespec *constructor_timeout) | |
896 | { | |
cf12a773 MD |
897 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
898 | char *str_delay; | |
11ff9c7d MD |
899 | int ret; |
900 | ||
69400ac4 | 901 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
902 | if (str_delay) { |
903 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
904 | } | |
905 | ||
906 | switch (constructor_delay_ms) { | |
907 | case -1:/* fall-through */ | |
908 | case 0: | |
909 | return constructor_delay_ms; | |
910 | default: | |
911 | break; | |
912 | } | |
913 | ||
914 | /* | |
915 | * If we are unable to find the current time, don't wait. | |
916 | */ | |
917 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
918 | if (ret) { | |
919 | return -1; | |
920 | } | |
95259bd0 MD |
921 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
922 | constructor_timeout->tv_nsec += | |
923 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
924 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
925 | constructor_timeout->tv_sec++; | |
926 | constructor_timeout->tv_nsec -= 1000000000UL; | |
927 | } | |
cf12a773 | 928 | return 1; |
11ff9c7d | 929 | } |
d9e99d10 | 930 | |
2691221a MD |
931 | /* |
932 | * sessiond monitoring thread: monitor presence of global and per-user | |
933 | * sessiond by polling the application common named pipe. | |
934 | */ | |
935 | /* TODO */ | |
936 | ||
edaa1431 | 937 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 938 | { |
11ff9c7d | 939 | struct timespec constructor_timeout; |
ae6a58bf | 940 | sigset_t sig_all_blocked, orig_parent_mask; |
1879f67f | 941 | pthread_attr_t thread_attr; |
cf12a773 | 942 | int timeout_mode; |
2691221a MD |
943 | int ret; |
944 | ||
edaa1431 MD |
945 | if (uatomic_xchg(&initialized, 1) == 1) |
946 | return; | |
947 | ||
eddd8d5d MD |
948 | /* |
949 | * Fixup interdependency between TLS fixup mutex (which happens | |
950 | * to be the dynamic linker mutex) and ust_lock, taken within | |
951 | * the ust lock. | |
952 | */ | |
953 | lttng_fixup_event_tls(); | |
f645cfa7 | 954 | lttng_fixup_ringbuffer_tls(); |
4158a15a | 955 | lttng_fixup_vtid_tls(); |
a903623f | 956 | lttng_fixup_nest_count_tls(); |
009745db | 957 | lttng_fixup_procname_tls(); |
eddd8d5d | 958 | |
edaa1431 MD |
959 | /* |
960 | * We want precise control over the order in which we construct | |
961 | * our sub-libraries vs starting to receive commands from | |
962 | * sessiond (otherwise leading to errors when trying to create | |
963 | * sessiond before the init functions are completed). | |
964 | */ | |
2691221a | 965 | init_usterr(); |
edaa1431 MD |
966 | init_tracepoint(); |
967 | ltt_ring_buffer_metadata_client_init(); | |
968 | ltt_ring_buffer_client_overwrite_init(); | |
969 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 970 | |
cf12a773 | 971 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 972 | |
95259bd0 | 973 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
974 | assert(!ret); |
975 | ||
8d20bf54 | 976 | ret = setup_local_apps(); |
2691221a | 977 | if (ret) { |
9ec6895c | 978 | DBG("local apps setup returned %d", ret); |
2691221a | 979 | } |
ae6a58bf WP |
980 | |
981 | /* A new thread created by pthread_create inherits the signal mask | |
982 | * from the parent. To avoid any signal being received by the | |
983 | * listener thread, we block all signals temporarily in the parent, | |
984 | * while we create the listener thread. | |
985 | */ | |
986 | sigfillset(&sig_all_blocked); | |
987 | ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask); | |
988 | if (ret) { | |
d94d802c | 989 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
990 | } |
991 | ||
1879f67f MG |
992 | ret = pthread_attr_init(&thread_attr); |
993 | if (ret) { | |
994 | ERR("pthread_attr_init: %s", strerror(ret)); | |
995 | } | |
996 | ret = pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED); | |
997 | if (ret) { | |
998 | ERR("pthread_attr_setdetachstate: %s", strerror(ret)); | |
999 | } | |
1000 | ||
1001 | ret = pthread_create(&global_apps.ust_listener, &thread_attr, | |
dde70ea0 | 1002 | ust_listener_thread, &global_apps); |
d94d802c MD |
1003 | if (ret) { |
1004 | ERR("pthread_create global: %s", strerror(ret)); | |
1005 | } | |
8d20bf54 | 1006 | if (local_apps.allowed) { |
1879f67f | 1007 | ret = pthread_create(&local_apps.ust_listener, &thread_attr, |
dde70ea0 | 1008 | ust_listener_thread, &local_apps); |
d94d802c MD |
1009 | if (ret) { |
1010 | ERR("pthread_create local: %s", strerror(ret)); | |
1011 | } | |
8d20bf54 MD |
1012 | } else { |
1013 | handle_register_done(&local_apps); | |
1014 | } | |
1879f67f MG |
1015 | ret = pthread_attr_destroy(&thread_attr); |
1016 | if (ret) { | |
1017 | ERR("pthread_attr_destroy: %s", strerror(ret)); | |
1018 | } | |
8d20bf54 | 1019 | |
ae6a58bf WP |
1020 | /* Restore original signal mask in parent */ |
1021 | ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL); | |
1022 | if (ret) { | |
d94d802c | 1023 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
1024 | } |
1025 | ||
cf12a773 MD |
1026 | switch (timeout_mode) { |
1027 | case 1: /* timeout wait */ | |
95259bd0 MD |
1028 | do { |
1029 | ret = sem_timedwait(&constructor_wait, | |
1030 | &constructor_timeout); | |
1031 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
1032 | if (ret < 0 && errno == ETIMEDOUT) { |
1033 | ERR("Timed out waiting for ltt-sessiond"); | |
1034 | } else { | |
1035 | assert(!ret); | |
1036 | } | |
1037 | break; | |
7b766b16 | 1038 | case -1:/* wait forever */ |
95259bd0 MD |
1039 | do { |
1040 | ret = sem_wait(&constructor_wait); | |
1041 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 1042 | assert(!ret); |
cf12a773 | 1043 | break; |
7b766b16 | 1044 | case 0: /* no timeout */ |
cf12a773 | 1045 | break; |
11ff9c7d | 1046 | } |
2691221a MD |
1047 | } |
1048 | ||
17dfb34b MD |
1049 | static |
1050 | void lttng_ust_cleanup(int exiting) | |
1051 | { | |
efe0de09 | 1052 | cleanup_sock_info(&global_apps, exiting); |
17dfb34b | 1053 | if (local_apps.allowed) { |
efe0de09 | 1054 | cleanup_sock_info(&local_apps, exiting); |
17dfb34b | 1055 | } |
efe0de09 MD |
1056 | /* |
1057 | * The teardown in this function all affect data structures | |
1058 | * accessed under the UST lock by the listener thread. This | |
1059 | * lock, along with the lttng_ust_comm_should_quit flag, ensure | |
1060 | * that none of these threads are accessing this data at this | |
1061 | * point. | |
1062 | */ | |
17dfb34b | 1063 | lttng_ust_abi_exit(); |
003fedf4 | 1064 | lttng_ust_events_exit(); |
17dfb34b MD |
1065 | ltt_ring_buffer_client_discard_exit(); |
1066 | ltt_ring_buffer_client_overwrite_exit(); | |
1067 | ltt_ring_buffer_metadata_client_exit(); | |
1068 | exit_tracepoint(); | |
1069 | if (!exiting) { | |
1070 | /* Reinitialize values for fork */ | |
1071 | sem_count = 2; | |
1072 | lttng_ust_comm_should_quit = 0; | |
1073 | initialized = 0; | |
1074 | } | |
1075 | } | |
1076 | ||
edaa1431 | 1077 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
1078 | { |
1079 | int ret; | |
1080 | ||
9eb62b9c MD |
1081 | /* |
1082 | * Using pthread_cancel here because: | |
1083 | * A) we don't want to hang application teardown. | |
1084 | * B) the thread is not allocating any resource. | |
1085 | */ | |
1ea11eab MD |
1086 | |
1087 | /* | |
1088 | * Require the communication thread to quit. Synchronize with | |
1089 | * mutexes to ensure it is not in a mutex critical section when | |
1090 | * pthread_cancel is later called. | |
1091 | */ | |
17dfb34b | 1092 | ust_lock(); |
1ea11eab | 1093 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 1094 | ust_unlock(); |
1ea11eab | 1095 | |
f5f94532 | 1096 | /* cancel threads */ |
1ea11eab | 1097 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c | 1098 | if (ret) { |
d94d802c MD |
1099 | ERR("Error cancelling global ust listener thread: %s", |
1100 | strerror(ret)); | |
2691221a | 1101 | } |
8d20bf54 MD |
1102 | if (local_apps.allowed) { |
1103 | ret = pthread_cancel(local_apps.ust_listener); | |
1104 | if (ret) { | |
d94d802c MD |
1105 | ERR("Error cancelling local ust listener thread: %s", |
1106 | strerror(ret)); | |
8d20bf54 | 1107 | } |
8d20bf54 | 1108 | } |
efe0de09 MD |
1109 | /* |
1110 | * Do NOT join threads: use of sys_futex makes it impossible to | |
1111 | * join the threads without using async-cancel, but async-cancel | |
1112 | * is delivered by a signal, which could hit the target thread | |
1113 | * anywhere in its code path, including while the ust_lock() is | |
1114 | * held, causing a deadlock for the other thread. Let the OS | |
1115 | * cleanup the threads if there are stalled in a syscall. | |
1116 | */ | |
17dfb34b | 1117 | lttng_ust_cleanup(1); |
2691221a | 1118 | } |
e822f505 MD |
1119 | |
1120 | /* | |
1121 | * We exclude the worker threads across fork and clone (except | |
1122 | * CLONE_VM), because these system calls only keep the forking thread | |
1123 | * running in the child. Therefore, we don't want to call fork or clone | |
1124 | * in the middle of an tracepoint or ust tracing state modification. | |
1125 | * Holding this mutex protects these structures across fork and clone. | |
1126 | */ | |
b728d87e | 1127 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
1128 | { |
1129 | /* | |
1130 | * Disable signals. This is to avoid that the child intervenes | |
1131 | * before it is properly setup for tracing. It is safer to | |
1132 | * disable all signals, because then we know we are not breaking | |
1133 | * anything by restoring the original mask. | |
1134 | */ | |
1135 | sigset_t all_sigs; | |
1136 | int ret; | |
1137 | ||
e8508a49 MD |
1138 | if (lttng_ust_nest_count) |
1139 | return; | |
e822f505 MD |
1140 | /* Disable signals */ |
1141 | sigfillset(&all_sigs); | |
b728d87e | 1142 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
1143 | if (ret == -1) { |
1144 | PERROR("sigprocmask"); | |
1145 | } | |
17dfb34b | 1146 | ust_lock(); |
e822f505 MD |
1147 | rcu_bp_before_fork(); |
1148 | } | |
1149 | ||
b728d87e | 1150 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
1151 | { |
1152 | int ret; | |
1153 | ||
17dfb34b MD |
1154 | DBG("process %d", getpid()); |
1155 | ust_unlock(); | |
e822f505 | 1156 | /* Restore signals */ |
23c8854a | 1157 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
1158 | if (ret == -1) { |
1159 | PERROR("sigprocmask"); | |
1160 | } | |
1161 | } | |
1162 | ||
b728d87e | 1163 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 1164 | { |
e8508a49 MD |
1165 | if (lttng_ust_nest_count) |
1166 | return; | |
17dfb34b | 1167 | DBG("process %d", getpid()); |
e822f505 MD |
1168 | rcu_bp_after_fork_parent(); |
1169 | /* Release mutexes and reenable signals */ | |
b728d87e | 1170 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
1171 | } |
1172 | ||
17dfb34b MD |
1173 | /* |
1174 | * After fork, in the child, we need to cleanup all the leftover state, | |
1175 | * except the worker thread which already magically disappeared thanks | |
1176 | * to the weird Linux fork semantics. After tyding up, we call | |
1177 | * lttng_ust_init() again to start over as a new PID. | |
1178 | * | |
1179 | * This is meant for forks() that have tracing in the child between the | |
1180 | * fork and following exec call (if there is any). | |
1181 | */ | |
b728d87e | 1182 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 1183 | { |
e8508a49 MD |
1184 | if (lttng_ust_nest_count) |
1185 | return; | |
17dfb34b | 1186 | DBG("process %d", getpid()); |
e822f505 MD |
1187 | /* Release urcu mutexes */ |
1188 | rcu_bp_after_fork_child(); | |
17dfb34b | 1189 | lttng_ust_cleanup(0); |
a93bfc45 | 1190 | lttng_context_vtid_reset(); |
e822f505 | 1191 | /* Release mutexes and reenable signals */ |
b728d87e | 1192 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1193 | lttng_ust_init(); |
e822f505 | 1194 | } |