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> |
74d81a6c | 45 | #include <lttng/ust-ctl.h> |
8c90a710 | 46 | #include <urcu/tls-compat.h> |
44c72f10 MD |
47 | #include <ust-comm.h> |
48 | #include <usterr-signal-safe.h> | |
cd54f6d9 | 49 | #include <helper.h> |
44c72f10 | 50 | #include "tracepoint-internal.h" |
7dd08bec | 51 | #include "lttng-tracer-core.h" |
08114193 | 52 | #include "compat.h" |
f645cfa7 | 53 | #include "../libringbuffer/tlsfixup.h" |
edaa1431 MD |
54 | |
55 | /* | |
56 | * Has lttng ust comm constructor been called ? | |
57 | */ | |
58 | static int initialized; | |
59 | ||
1ea11eab | 60 | /* |
17dfb34b MD |
61 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
62 | * Held when handling a command, also held by fork() to deal with | |
63 | * removal of threads, and by exit path. | |
1ea11eab | 64 | */ |
1ea11eab MD |
65 | |
66 | /* Should the ust comm thread quit ? */ | |
67 | static int lttng_ust_comm_should_quit; | |
68 | ||
11ff9c7d MD |
69 | /* |
70 | * Wait for either of these before continuing to the main | |
71 | * program: | |
72 | * - the register_done message from sessiond daemon | |
73 | * (will let the sessiond daemon enable sessions before main | |
74 | * starts.) | |
75 | * - sessiond daemon is not reachable. | |
76 | * - timeout (ensuring applications are resilient to session | |
77 | * daemon problems). | |
78 | */ | |
79 | static sem_t constructor_wait; | |
950aab0c MD |
80 | /* |
81 | * Doing this for both the global and local sessiond. | |
82 | */ | |
95259bd0 | 83 | static int sem_count = { 2 }; |
11ff9c7d | 84 | |
e8508a49 MD |
85 | /* |
86 | * Counting nesting within lttng-ust. Used to ensure that calling fork() | |
87 | * from liblttng-ust does not execute the pre/post fork handlers. | |
88 | */ | |
8c90a710 | 89 | static DEFINE_URCU_TLS(int, lttng_ust_nest_count); |
e8508a49 | 90 | |
1ea11eab MD |
91 | /* |
92 | * Info about socket and associated listener thread. | |
93 | */ | |
94 | struct sock_info { | |
11ff9c7d | 95 | const char *name; |
1ea11eab | 96 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 97 | int root_handle; |
8d20bf54 MD |
98 | int constructor_sem_posted; |
99 | int allowed; | |
44e073f5 | 100 | int global; |
e33f3265 | 101 | int thread_active; |
7fc90dca MD |
102 | |
103 | char sock_path[PATH_MAX]; | |
104 | int socket; | |
32ce8569 | 105 | int notify_socket; |
7fc90dca MD |
106 | |
107 | char wait_shm_path[PATH_MAX]; | |
108 | char *wait_shm_mmap; | |
1ea11eab | 109 | }; |
2691221a MD |
110 | |
111 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 112 | struct sock_info global_apps = { |
11ff9c7d | 113 | .name = "global", |
44e073f5 | 114 | .global = 1, |
7fc90dca | 115 | |
46050b1a | 116 | .root_handle = -1, |
8d20bf54 | 117 | .allowed = 1, |
e33f3265 | 118 | .thread_active = 0, |
7fc90dca | 119 | |
32ce8569 | 120 | .sock_path = LTTNG_DEFAULT_RUNDIR "/" LTTNG_UST_SOCK_FILENAME, |
7fc90dca | 121 | .socket = -1, |
32ce8569 | 122 | .notify_socket = -1, |
7fc90dca | 123 | |
32ce8569 | 124 | .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME, |
1ea11eab | 125 | }; |
2691221a MD |
126 | |
127 | /* TODO: allow global_apps_sock_path override */ | |
128 | ||
1ea11eab | 129 | struct sock_info local_apps = { |
11ff9c7d | 130 | .name = "local", |
44e073f5 | 131 | .global = 0, |
46050b1a | 132 | .root_handle = -1, |
8d20bf54 | 133 | .allowed = 0, /* Check setuid bit first */ |
e33f3265 | 134 | .thread_active = 0, |
7fc90dca MD |
135 | |
136 | .socket = -1, | |
32ce8569 | 137 | .notify_socket = -1, |
1ea11eab | 138 | }; |
2691221a | 139 | |
37ed587a MD |
140 | static int wait_poll_fallback; |
141 | ||
74d81a6c MD |
142 | static const char *cmd_name_mapping[] = { |
143 | [ LTTNG_UST_RELEASE ] = "Release", | |
144 | [ LTTNG_UST_SESSION ] = "Create Session", | |
145 | [ LTTNG_UST_TRACER_VERSION ] = "Get Tracer Version", | |
146 | ||
147 | [ LTTNG_UST_TRACEPOINT_LIST ] = "Create Tracepoint List", | |
148 | [ LTTNG_UST_WAIT_QUIESCENT ] = "Wait for Quiescent State", | |
149 | [ LTTNG_UST_REGISTER_DONE ] = "Registration Done", | |
150 | [ LTTNG_UST_TRACEPOINT_FIELD_LIST ] = "Create Tracepoint Field List", | |
151 | ||
152 | /* Session FD commands */ | |
153 | [ LTTNG_UST_CHANNEL ] = "Create Channel", | |
154 | [ LTTNG_UST_SESSION_START ] = "Start Session", | |
155 | [ LTTNG_UST_SESSION_STOP ] = "Stop Session", | |
156 | ||
157 | /* Channel FD commands */ | |
158 | [ LTTNG_UST_STREAM ] = "Create Stream", | |
159 | [ LTTNG_UST_EVENT ] = "Create Event", | |
160 | ||
161 | /* Event and Channel FD commands */ | |
162 | [ LTTNG_UST_CONTEXT ] = "Create Context", | |
163 | [ LTTNG_UST_FLUSH_BUFFER ] = "Flush Buffer", | |
164 | ||
165 | /* Event, Channel and Session commands */ | |
166 | [ LTTNG_UST_ENABLE ] = "Enable", | |
167 | [ LTTNG_UST_DISABLE ] = "Disable", | |
168 | ||
169 | /* Tracepoint list commands */ | |
170 | [ LTTNG_UST_TRACEPOINT_LIST_GET ] = "List Next Tracepoint", | |
171 | [ LTTNG_UST_TRACEPOINT_FIELD_LIST_GET ] = "List Next Tracepoint Field", | |
172 | ||
173 | /* Event FD commands */ | |
174 | [ LTTNG_UST_FILTER ] = "Create Filter", | |
175 | }; | |
176 | ||
7dd08bec MD |
177 | extern void lttng_ring_buffer_client_overwrite_init(void); |
178 | extern void lttng_ring_buffer_client_discard_init(void); | |
179 | extern void lttng_ring_buffer_metadata_client_init(void); | |
180 | extern void lttng_ring_buffer_client_overwrite_exit(void); | |
181 | extern void lttng_ring_buffer_client_discard_exit(void); | |
182 | extern void lttng_ring_buffer_metadata_client_exit(void); | |
edaa1431 | 183 | |
a903623f MD |
184 | /* |
185 | * Force a read (imply TLS fixup for dlopen) of TLS variables. | |
186 | */ | |
187 | static | |
188 | void lttng_fixup_nest_count_tls(void) | |
189 | { | |
8c90a710 | 190 | asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count))); |
a903623f MD |
191 | } |
192 | ||
32ce8569 MD |
193 | int lttng_get_notify_socket(void *owner) |
194 | { | |
195 | struct sock_info *info = owner; | |
196 | ||
197 | return info->notify_socket; | |
198 | } | |
199 | ||
74d81a6c MD |
200 | static |
201 | void print_cmd(int cmd, int handle) | |
202 | { | |
203 | const char *cmd_name = "Unknown"; | |
204 | ||
205 | if (cmd_name_mapping[cmd]) { | |
206 | cmd_name = cmd_name_mapping[cmd]; | |
207 | } | |
208 | DBG("Message Received \"%s\", Handle \"%s\" (%d)", cmd_name, | |
209 | lttng_ust_obj_get_name(handle), handle); | |
210 | } | |
211 | ||
2691221a | 212 | static |
8d20bf54 | 213 | int setup_local_apps(void) |
2691221a MD |
214 | { |
215 | const char *home_dir; | |
7fc90dca | 216 | uid_t uid; |
2691221a | 217 | |
7fc90dca | 218 | uid = getuid(); |
8d20bf54 MD |
219 | /* |
220 | * Disallow per-user tracing for setuid binaries. | |
221 | */ | |
7fc90dca | 222 | if (uid != geteuid()) { |
9ec6895c | 223 | assert(local_apps.allowed == 0); |
d0a1ae63 | 224 | return 0; |
8d20bf54 | 225 | } |
2691221a | 226 | home_dir = (const char *) getenv("HOME"); |
9ec6895c MD |
227 | if (!home_dir) { |
228 | WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing."); | |
229 | assert(local_apps.allowed == 0); | |
2691221a | 230 | return -ENOENT; |
9ec6895c MD |
231 | } |
232 | local_apps.allowed = 1; | |
32ce8569 MD |
233 | snprintf(local_apps.sock_path, PATH_MAX, "%s/%s/%s", |
234 | home_dir, | |
235 | LTTNG_DEFAULT_HOME_RUNDIR, | |
236 | LTTNG_UST_SOCK_FILENAME); | |
237 | snprintf(local_apps.wait_shm_path, PATH_MAX, "/%s-%u", | |
238 | LTTNG_UST_WAIT_FILENAME, | |
239 | uid); | |
2691221a MD |
240 | return 0; |
241 | } | |
242 | ||
243 | static | |
32ce8569 | 244 | int register_to_sessiond(int socket, enum ustctl_socket_type type) |
2691221a | 245 | { |
32ce8569 MD |
246 | return ustcomm_send_reg_msg(socket, |
247 | type, | |
248 | CAA_BITS_PER_LONG, | |
249 | lttng_alignof(uint8_t) * CHAR_BIT, | |
250 | lttng_alignof(uint16_t) * CHAR_BIT, | |
251 | lttng_alignof(uint32_t) * CHAR_BIT, | |
252 | lttng_alignof(uint64_t) * CHAR_BIT, | |
253 | lttng_alignof(unsigned long) * CHAR_BIT); | |
2691221a MD |
254 | } |
255 | ||
d9e99d10 | 256 | static |
57773204 | 257 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 258 | { |
9eb62b9c | 259 | ssize_t len; |
d3a492d1 | 260 | |
57773204 | 261 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 262 | switch (len) { |
a4be8962 | 263 | case sizeof(*lur): |
d3a492d1 MD |
264 | DBG("message successfully sent"); |
265 | return 0; | |
7bc53e94 MD |
266 | default: |
267 | if (len == -ECONNRESET) { | |
268 | DBG("remote end closed connection"); | |
d3a492d1 MD |
269 | return 0; |
270 | } | |
7bc53e94 MD |
271 | if (len < 0) |
272 | return len; | |
273 | DBG("incorrect message size: %zd", len); | |
274 | return -EINVAL; | |
d3a492d1 MD |
275 | } |
276 | } | |
277 | ||
278 | static | |
edaa1431 | 279 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
280 | { |
281 | int ret; | |
282 | ||
edaa1431 MD |
283 | if (sock_info->constructor_sem_posted) |
284 | return 0; | |
285 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
286 | if (uatomic_read(&sem_count) <= 0) { |
287 | return 0; | |
288 | } | |
95259bd0 MD |
289 | ret = uatomic_add_return(&sem_count, -1); |
290 | if (ret == 0) { | |
291 | ret = sem_post(&constructor_wait); | |
292 | assert(!ret); | |
293 | } | |
11ff9c7d MD |
294 | return 0; |
295 | } | |
296 | ||
297 | static | |
298 | int handle_message(struct sock_info *sock_info, | |
57773204 | 299 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 300 | { |
1ea11eab | 301 | int ret = 0; |
b61ce3b2 | 302 | const struct lttng_ust_objd_ops *ops; |
57773204 | 303 | struct ustcomm_ust_reply lur; |
ef9ff354 | 304 | union ust_args args; |
40003310 | 305 | ssize_t len; |
1ea11eab | 306 | |
17dfb34b | 307 | ust_lock(); |
1ea11eab | 308 | |
46050b1a MD |
309 | memset(&lur, 0, sizeof(lur)); |
310 | ||
1ea11eab | 311 | if (lttng_ust_comm_should_quit) { |
74d81a6c | 312 | ret = -LTTNG_UST_ERR_EXITING; |
1ea11eab MD |
313 | goto end; |
314 | } | |
9eb62b9c | 315 | |
46050b1a MD |
316 | ops = objd_ops(lum->handle); |
317 | if (!ops) { | |
318 | ret = -ENOENT; | |
319 | goto end; | |
1ea11eab | 320 | } |
46050b1a MD |
321 | |
322 | switch (lum->cmd) { | |
11ff9c7d MD |
323 | case LTTNG_UST_REGISTER_DONE: |
324 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 325 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
326 | else |
327 | ret = -EINVAL; | |
328 | break; | |
46050b1a MD |
329 | case LTTNG_UST_RELEASE: |
330 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
331 | ret = -EPERM; | |
332 | else | |
d4419b81 | 333 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 | 334 | break; |
2d78951a MD |
335 | case LTTNG_UST_FILTER: |
336 | { | |
337 | /* Receive filter data */ | |
f488575f | 338 | struct lttng_ust_filter_bytecode_node *bytecode; |
2d78951a | 339 | |
cd54f6d9 | 340 | if (lum->u.filter.data_size > FILTER_BYTECODE_MAX_LEN) { |
7bc53e94 | 341 | ERR("Filter data size is too large: %u bytes", |
2d78951a MD |
342 | lum->u.filter.data_size); |
343 | ret = -EINVAL; | |
344 | goto error; | |
345 | } | |
2734ca65 | 346 | |
885b1dfd | 347 | if (lum->u.filter.reloc_offset > lum->u.filter.data_size) { |
7bc53e94 | 348 | ERR("Filter reloc offset %u is not within data", |
2734ca65 CB |
349 | lum->u.filter.reloc_offset); |
350 | ret = -EINVAL; | |
351 | goto error; | |
352 | } | |
353 | ||
cd54f6d9 MD |
354 | bytecode = zmalloc(sizeof(*bytecode) + lum->u.filter.data_size); |
355 | if (!bytecode) { | |
356 | ret = -ENOMEM; | |
357 | goto error; | |
358 | } | |
f488575f | 359 | len = ustcomm_recv_unix_sock(sock, bytecode->bc.data, |
2d78951a MD |
360 | lum->u.filter.data_size); |
361 | switch (len) { | |
362 | case 0: /* orderly shutdown */ | |
363 | ret = 0; | |
cd54f6d9 | 364 | free(bytecode); |
2d78951a | 365 | goto error; |
2d78951a MD |
366 | default: |
367 | if (len == lum->u.filter.data_size) { | |
7bc53e94 | 368 | DBG("filter data received"); |
2d78951a | 369 | break; |
7bc53e94 MD |
370 | } else if (len < 0) { |
371 | DBG("Receive failed from lttng-sessiond with errno %d", (int) -len); | |
372 | if (len == -ECONNRESET) { | |
373 | ERR("%s remote end closed connection", sock_info->name); | |
374 | ret = len; | |
375 | free(bytecode); | |
376 | goto error; | |
377 | } | |
378 | ret = len; | |
379 | goto end; | |
2d78951a | 380 | } else { |
7bc53e94 | 381 | DBG("incorrect filter data message size: %zd", len); |
2d78951a | 382 | ret = -EINVAL; |
cd54f6d9 | 383 | free(bytecode); |
2d78951a MD |
384 | goto end; |
385 | } | |
386 | } | |
f488575f MD |
387 | bytecode->bc.len = lum->u.filter.data_size; |
388 | bytecode->bc.reloc_offset = lum->u.filter.reloc_offset; | |
3f6fd224 | 389 | bytecode->bc.seqnum = lum->u.filter.seqnum; |
cd54f6d9 | 390 | if (ops->cmd) { |
2d78951a | 391 | ret = ops->cmd(lum->handle, lum->cmd, |
cd54f6d9 | 392 | (unsigned long) bytecode, |
f59ed768 | 393 | &args, sock_info); |
cd54f6d9 MD |
394 | if (ret) { |
395 | free(bytecode); | |
396 | } | |
397 | /* don't free bytecode if everything went fine. */ | |
398 | } else { | |
2d78951a | 399 | ret = -ENOSYS; |
cd54f6d9 MD |
400 | free(bytecode); |
401 | } | |
2d78951a MD |
402 | break; |
403 | } | |
74d81a6c MD |
404 | case LTTNG_UST_CHANNEL: |
405 | { | |
406 | void *chan_data; | |
407 | ||
408 | len = ustcomm_recv_channel_from_sessiond(sock, | |
409 | &chan_data, lum->u.channel.len); | |
410 | switch (len) { | |
411 | case 0: /* orderly shutdown */ | |
412 | ret = 0; | |
413 | goto error; | |
414 | default: | |
415 | if (len == lum->u.channel.len) { | |
416 | DBG("channel data received"); | |
417 | break; | |
418 | } else if (len < 0) { | |
419 | DBG("Receive failed from lttng-sessiond with errno %d", (int) -len); | |
420 | if (len == -ECONNRESET) { | |
421 | ERR("%s remote end closed connection", sock_info->name); | |
422 | ret = len; | |
423 | goto error; | |
424 | } | |
425 | ret = len; | |
426 | goto end; | |
427 | } else { | |
428 | DBG("incorrect channel data message size: %zd", len); | |
429 | ret = -EINVAL; | |
430 | goto end; | |
431 | } | |
432 | } | |
433 | args.channel.chan_data = chan_data; | |
434 | if (ops->cmd) | |
435 | ret = ops->cmd(lum->handle, lum->cmd, | |
436 | (unsigned long) &lum->u, | |
437 | &args, sock_info); | |
438 | else | |
439 | ret = -ENOSYS; | |
440 | break; | |
441 | } | |
442 | case LTTNG_UST_STREAM: | |
443 | { | |
444 | /* Receive shm_fd, wakeup_fd */ | |
445 | ret = ustcomm_recv_stream_from_sessiond(sock, | |
446 | &lum->u.stream.len, | |
447 | &args.stream.shm_fd, | |
448 | &args.stream.wakeup_fd); | |
449 | if (ret) { | |
450 | goto end; | |
451 | } | |
452 | if (ops->cmd) | |
453 | ret = ops->cmd(lum->handle, lum->cmd, | |
454 | (unsigned long) &lum->u, | |
455 | &args, sock_info); | |
456 | else | |
457 | ret = -ENOSYS; | |
458 | break; | |
459 | } | |
d9e99d10 | 460 | default: |
46050b1a MD |
461 | if (ops->cmd) |
462 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 | 463 | (unsigned long) &lum->u, |
f59ed768 | 464 | &args, sock_info); |
46050b1a MD |
465 | else |
466 | ret = -ENOSYS; | |
467 | break; | |
d9e99d10 | 468 | } |
46050b1a | 469 | |
1ea11eab | 470 | end: |
46050b1a MD |
471 | lur.handle = lum->handle; |
472 | lur.cmd = lum->cmd; | |
473 | lur.ret_val = ret; | |
474 | if (ret >= 0) { | |
7bc53e94 | 475 | lur.ret_code = LTTNG_UST_OK; |
46050b1a | 476 | } else { |
7bc53e94 MD |
477 | /* |
478 | * Use -LTTNG_UST_ERR as wildcard for UST internal | |
479 | * error that are not caused by the transport, except if | |
480 | * we already have a more precise error message to | |
481 | * report. | |
482 | */ | |
64b2564e DG |
483 | if (ret > -LTTNG_UST_ERR) { |
484 | /* Translate code to UST error. */ | |
485 | switch (ret) { | |
486 | case -EEXIST: | |
487 | lur.ret_code = -LTTNG_UST_ERR_EXIST; | |
488 | break; | |
489 | case -EINVAL: | |
490 | lur.ret_code = -LTTNG_UST_ERR_INVAL; | |
491 | break; | |
492 | case -ENOENT: | |
493 | lur.ret_code = -LTTNG_UST_ERR_NOENT; | |
494 | break; | |
495 | case -EPERM: | |
496 | lur.ret_code = -LTTNG_UST_ERR_PERM; | |
497 | break; | |
498 | case -ENOSYS: | |
499 | lur.ret_code = -LTTNG_UST_ERR_NOSYS; | |
500 | break; | |
501 | default: | |
502 | lur.ret_code = -LTTNG_UST_ERR; | |
503 | break; | |
504 | } | |
505 | } else { | |
7bc53e94 | 506 | lur.ret_code = ret; |
64b2564e | 507 | } |
46050b1a | 508 | } |
e6ea14c5 MD |
509 | if (ret >= 0) { |
510 | switch (lum->cmd) { | |
e6ea14c5 MD |
511 | case LTTNG_UST_TRACER_VERSION: |
512 | lur.u.version = lum->u.version; | |
513 | break; | |
514 | case LTTNG_UST_TRACEPOINT_LIST_GET: | |
515 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); | |
516 | break; | |
517 | } | |
381c0f1e | 518 | } |
74d81a6c | 519 | DBG("Return value: %d", lur.ret_val); |
46050b1a | 520 | ret = send_reply(sock, &lur); |
193183fb | 521 | if (ret < 0) { |
7bc53e94 | 522 | DBG("error sending reply"); |
193183fb MD |
523 | goto error; |
524 | } | |
46050b1a | 525 | |
40003310 MD |
526 | /* |
527 | * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field | |
528 | * after the reply. | |
529 | */ | |
7bc53e94 | 530 | if (lur.ret_code == LTTNG_UST_OK) { |
40003310 MD |
531 | switch (lum->cmd) { |
532 | case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET: | |
533 | len = ustcomm_send_unix_sock(sock, | |
534 | &args.field_list.entry, | |
535 | sizeof(args.field_list.entry)); | |
7bc53e94 MD |
536 | if (len < 0) { |
537 | ret = len; | |
538 | goto error; | |
539 | } | |
40003310 | 540 | if (len != sizeof(args.field_list.entry)) { |
7bc53e94 | 541 | ret = -EINVAL; |
40003310 MD |
542 | goto error; |
543 | } | |
544 | } | |
545 | } | |
ef9ff354 | 546 | |
381c0f1e | 547 | error: |
17dfb34b | 548 | ust_unlock(); |
1ea11eab | 549 | return ret; |
d9e99d10 MD |
550 | } |
551 | ||
46050b1a | 552 | static |
efe0de09 | 553 | void cleanup_sock_info(struct sock_info *sock_info, int exiting) |
46050b1a MD |
554 | { |
555 | int ret; | |
556 | ||
557 | if (sock_info->socket != -1) { | |
e6973a89 | 558 | ret = ustcomm_close_unix_sock(sock_info->socket); |
46050b1a | 559 | if (ret) { |
32ce8569 | 560 | ERR("Error closing ust cmd socket"); |
46050b1a MD |
561 | } |
562 | sock_info->socket = -1; | |
563 | } | |
32ce8569 MD |
564 | if (sock_info->notify_socket != -1) { |
565 | ret = ustcomm_close_unix_sock(sock_info->notify_socket); | |
566 | if (ret) { | |
567 | ERR("Error closing ust notify socket"); | |
568 | } | |
569 | sock_info->notify_socket = -1; | |
570 | } | |
46050b1a | 571 | if (sock_info->root_handle != -1) { |
d4419b81 | 572 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
573 | if (ret) { |
574 | ERR("Error unref root handle"); | |
575 | } | |
576 | sock_info->root_handle = -1; | |
577 | } | |
318dfea9 | 578 | sock_info->constructor_sem_posted = 0; |
efe0de09 MD |
579 | /* |
580 | * wait_shm_mmap is used by listener threads outside of the | |
581 | * ust lock, so we cannot tear it down ourselves, because we | |
582 | * cannot join on these threads. Leave this task to the OS | |
583 | * process exit. | |
584 | */ | |
585 | if (!exiting && sock_info->wait_shm_mmap) { | |
7fc90dca MD |
586 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); |
587 | if (ret) { | |
588 | ERR("Error unmapping wait shm"); | |
589 | } | |
590 | sock_info->wait_shm_mmap = NULL; | |
591 | } | |
592 | } | |
593 | ||
58d4b2a2 | 594 | /* |
33bbeb90 MD |
595 | * Using fork to set umask in the child process (not multi-thread safe). |
596 | * We deal with the shm_open vs ftruncate race (happening when the | |
597 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
598 | * safety against shm_unlink) by simply letting the mmap fail and | |
599 | * retrying after a few seconds. | |
600 | * For global shm, everybody has rw access to it until the sessiond | |
601 | * starts. | |
58d4b2a2 | 602 | */ |
7fc90dca | 603 | static |
58d4b2a2 | 604 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 605 | { |
7fc90dca | 606 | int wait_shm_fd, ret; |
58d4b2a2 | 607 | pid_t pid; |
44e073f5 | 608 | |
58d4b2a2 | 609 | /* |
33bbeb90 | 610 | * Try to open read-only. |
58d4b2a2 | 611 | */ |
33bbeb90 | 612 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
613 | if (wait_shm_fd >= 0) { |
614 | goto end; | |
615 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
616 | /* | |
33bbeb90 MD |
617 | * Real-only open did not work, and it's not because the |
618 | * entry was not present. It's a failure that prohibits | |
619 | * using shm. | |
58d4b2a2 | 620 | */ |
7fc90dca | 621 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 622 | goto end; |
7fc90dca MD |
623 | } |
624 | /* | |
58d4b2a2 MD |
625 | * If the open failed because the file did not exist, try |
626 | * creating it ourself. | |
7fc90dca | 627 | */ |
8c90a710 | 628 | URCU_TLS(lttng_ust_nest_count)++; |
58d4b2a2 | 629 | pid = fork(); |
8c90a710 | 630 | URCU_TLS(lttng_ust_nest_count)--; |
58d4b2a2 MD |
631 | if (pid > 0) { |
632 | int status; | |
633 | ||
634 | /* | |
635 | * Parent: wait for child to return, in which case the | |
636 | * shared memory map will have been created. | |
637 | */ | |
638 | pid = wait(&status); | |
b7d3cb32 | 639 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
640 | wait_shm_fd = -1; |
641 | goto end; | |
7fc90dca | 642 | } |
58d4b2a2 MD |
643 | /* |
644 | * Try to open read-only again after creation. | |
645 | */ | |
33bbeb90 | 646 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
647 | if (wait_shm_fd < 0) { |
648 | /* | |
649 | * Real-only open did not work. It's a failure | |
650 | * that prohibits using shm. | |
651 | */ | |
652 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
653 | goto end; | |
654 | } | |
655 | goto end; | |
656 | } else if (pid == 0) { | |
657 | int create_mode; | |
658 | ||
659 | /* Child */ | |
33bbeb90 | 660 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 661 | if (sock_info->global) |
33bbeb90 | 662 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
663 | /* |
664 | * We're alone in a child process, so we can modify the | |
665 | * process-wide umask. | |
666 | */ | |
33bbeb90 | 667 | umask(~create_mode); |
58d4b2a2 | 668 | /* |
33bbeb90 MD |
669 | * Try creating shm (or get rw access). |
670 | * We don't do an exclusive open, because we allow other | |
671 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
672 | */ |
673 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
674 | O_RDWR | O_CREAT, create_mode); | |
675 | if (wait_shm_fd >= 0) { | |
676 | ret = ftruncate(wait_shm_fd, mmap_size); | |
677 | if (ret) { | |
678 | PERROR("ftruncate"); | |
b0c1425d | 679 | _exit(EXIT_FAILURE); |
58d4b2a2 | 680 | } |
b0c1425d | 681 | _exit(EXIT_SUCCESS); |
58d4b2a2 | 682 | } |
33bbeb90 MD |
683 | /* |
684 | * For local shm, we need to have rw access to accept | |
685 | * opening it: this means the local sessiond will be | |
686 | * able to wake us up. For global shm, we open it even | |
687 | * if rw access is not granted, because the root.root | |
688 | * sessiond will be able to override all rights and wake | |
689 | * us up. | |
690 | */ | |
691 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 | 692 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
5d3bc5ed | 693 | _exit(EXIT_FAILURE); |
58d4b2a2 MD |
694 | } |
695 | /* | |
33bbeb90 MD |
696 | * The shm exists, but we cannot open it RW. Report |
697 | * success. | |
58d4b2a2 | 698 | */ |
5d3bc5ed | 699 | _exit(EXIT_SUCCESS); |
58d4b2a2 MD |
700 | } else { |
701 | return -1; | |
7fc90dca | 702 | } |
58d4b2a2 | 703 | end: |
33bbeb90 MD |
704 | if (wait_shm_fd >= 0 && !sock_info->global) { |
705 | struct stat statbuf; | |
706 | ||
707 | /* | |
708 | * Ensure that our user is the owner of the shm file for | |
709 | * local shm. If we do not own the file, it means our | |
710 | * sessiond will not have access to wake us up (there is | |
711 | * probably a rogue process trying to fake our | |
712 | * sessiond). Fallback to polling method in this case. | |
713 | */ | |
714 | ret = fstat(wait_shm_fd, &statbuf); | |
715 | if (ret) { | |
716 | PERROR("fstat"); | |
717 | goto error_close; | |
718 | } | |
719 | if (statbuf.st_uid != getuid()) | |
720 | goto error_close; | |
721 | } | |
58d4b2a2 | 722 | return wait_shm_fd; |
33bbeb90 MD |
723 | |
724 | error_close: | |
725 | ret = close(wait_shm_fd); | |
726 | if (ret) { | |
727 | PERROR("Error closing fd"); | |
728 | } | |
729 | return -1; | |
58d4b2a2 MD |
730 | } |
731 | ||
732 | static | |
733 | char *get_map_shm(struct sock_info *sock_info) | |
734 | { | |
735 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
736 | int wait_shm_fd, ret; | |
737 | char *wait_shm_mmap; | |
738 | ||
739 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
740 | if (wait_shm_fd < 0) { | |
741 | goto error; | |
44e073f5 | 742 | } |
7fc90dca MD |
743 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
744 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
745 | /* close shm fd immediately after taking the mmap reference */ |
746 | ret = close(wait_shm_fd); | |
747 | if (ret) { | |
33bbeb90 MD |
748 | PERROR("Error closing fd"); |
749 | } | |
750 | if (wait_shm_mmap == MAP_FAILED) { | |
751 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
752 | goto error; | |
7fc90dca MD |
753 | } |
754 | return wait_shm_mmap; | |
755 | ||
756 | error: | |
757 | return NULL; | |
758 | } | |
759 | ||
760 | static | |
761 | void wait_for_sessiond(struct sock_info *sock_info) | |
762 | { | |
efe0de09 | 763 | int ret; |
80e2814b | 764 | |
7fc90dca MD |
765 | ust_lock(); |
766 | if (lttng_ust_comm_should_quit) { | |
767 | goto quit; | |
768 | } | |
37ed587a MD |
769 | if (wait_poll_fallback) { |
770 | goto error; | |
771 | } | |
7fc90dca MD |
772 | if (!sock_info->wait_shm_mmap) { |
773 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
774 | if (!sock_info->wait_shm_mmap) | |
775 | goto error; | |
776 | } | |
777 | ust_unlock(); | |
778 | ||
779 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
780 | /* Wait for futex wakeup */ |
781 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
782 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
783 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 784 | if (ret < 0) { |
37ed587a MD |
785 | if (errno == EFAULT) { |
786 | wait_poll_fallback = 1; | |
a8b870ad | 787 | DBG( |
37ed587a MD |
788 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
789 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
790 | "Please upgrade your kernel " | |
791 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
792 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
793 | if (ust_debug()) |
794 | PERROR("futex"); | |
37ed587a | 795 | } |
80e2814b MD |
796 | } |
797 | } | |
7fc90dca MD |
798 | return; |
799 | ||
800 | quit: | |
801 | ust_unlock(); | |
802 | return; | |
803 | ||
804 | error: | |
805 | ust_unlock(); | |
7fc90dca | 806 | return; |
46050b1a MD |
807 | } |
808 | ||
1ea11eab MD |
809 | /* |
810 | * This thread does not allocate any resource, except within | |
811 | * handle_message, within mutex protection. This mutex protects against | |
812 | * fork and exit. | |
98bf993f | 813 | * The other moment it allocates resources is at socket connection, which |
1ea11eab MD |
814 | * is also protected by the mutex. |
815 | */ | |
d9e99d10 MD |
816 | static |
817 | void *ust_listener_thread(void *arg) | |
818 | { | |
1ea11eab | 819 | struct sock_info *sock_info = arg; |
c0eedf81 | 820 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
32ce8569 MD |
821 | int open_sock[2]; |
822 | int i; | |
d9e99d10 | 823 | |
9eb62b9c MD |
824 | /* Restart trying to connect to the session daemon */ |
825 | restart: | |
c0eedf81 MD |
826 | if (prev_connect_failed) { |
827 | /* Wait for sessiond availability with pipe */ | |
828 | wait_for_sessiond(sock_info); | |
829 | if (has_waited) { | |
830 | has_waited = 0; | |
831 | /* | |
832 | * Sleep for 5 seconds before retrying after a | |
833 | * sequence of failure / wait / failure. This | |
834 | * deals with a killed or broken session daemon. | |
835 | */ | |
836 | sleep(5); | |
837 | } | |
838 | has_waited = 1; | |
839 | prev_connect_failed = 0; | |
840 | } | |
17dfb34b | 841 | ust_lock(); |
1ea11eab MD |
842 | |
843 | if (lttng_ust_comm_should_quit) { | |
1ea11eab MD |
844 | goto quit; |
845 | } | |
9eb62b9c | 846 | |
1ea11eab | 847 | if (sock_info->socket != -1) { |
e6973a89 | 848 | ret = ustcomm_close_unix_sock(sock_info->socket); |
1ea11eab | 849 | if (ret) { |
32ce8569 MD |
850 | ERR("Error closing %s ust cmd socket", |
851 | sock_info->name); | |
1ea11eab MD |
852 | } |
853 | sock_info->socket = -1; | |
854 | } | |
32ce8569 MD |
855 | if (sock_info->notify_socket != -1) { |
856 | ret = ustcomm_close_unix_sock(sock_info->notify_socket); | |
857 | if (ret) { | |
858 | ERR("Error closing %s ust notify socket", | |
859 | sock_info->name); | |
860 | } | |
861 | sock_info->notify_socket = -1; | |
862 | } | |
46050b1a | 863 | |
9eb62b9c | 864 | /* Register */ |
32ce8569 MD |
865 | for (i = 0; i < 2; i++) { |
866 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); | |
867 | if (ret < 0) { | |
868 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); | |
869 | prev_connect_failed = 1; | |
870 | /* | |
871 | * If we cannot find the sessiond daemon, don't delay | |
872 | * constructor execution. | |
873 | */ | |
874 | ret = handle_register_done(sock_info); | |
875 | assert(!ret); | |
876 | ust_unlock(); | |
877 | goto restart; | |
878 | } | |
879 | open_sock[i] = ret; | |
46050b1a MD |
880 | } |
881 | ||
32ce8569 MD |
882 | sock_info->socket = open_sock[0]; |
883 | sock_info->notify_socket = open_sock[1]; | |
46050b1a MD |
884 | |
885 | /* | |
886 | * Create only one root handle per listener thread for the whole | |
f59ed768 MD |
887 | * process lifetime, so we ensure we get ID which is statically |
888 | * assigned to the root handle. | |
46050b1a MD |
889 | */ |
890 | if (sock_info->root_handle == -1) { | |
891 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 892 | if (ret < 0) { |
46050b1a | 893 | ERR("Error creating root handle"); |
46050b1a MD |
894 | goto quit; |
895 | } | |
896 | sock_info->root_handle = ret; | |
9eb62b9c | 897 | } |
1ea11eab | 898 | |
32ce8569 | 899 | ret = register_to_sessiond(sock_info->socket, USTCTL_SOCKET_CMD); |
9eb62b9c | 900 | if (ret < 0) { |
32ce8569 MD |
901 | ERR("Error registering to %s ust cmd socket", |
902 | sock_info->name); | |
c0eedf81 | 903 | prev_connect_failed = 1; |
11ff9c7d MD |
904 | /* |
905 | * If we cannot register to the sessiond daemon, don't | |
906 | * delay constructor execution. | |
907 | */ | |
edaa1431 | 908 | ret = handle_register_done(sock_info); |
11ff9c7d | 909 | assert(!ret); |
17dfb34b | 910 | ust_unlock(); |
9eb62b9c MD |
911 | goto restart; |
912 | } | |
32ce8569 MD |
913 | ret = register_to_sessiond(sock_info->notify_socket, |
914 | USTCTL_SOCKET_NOTIFY); | |
915 | if (ret < 0) { | |
916 | ERR("Error registering to %s ust notify socket", | |
917 | sock_info->name); | |
918 | prev_connect_failed = 1; | |
919 | /* | |
920 | * If we cannot register to the sessiond daemon, don't | |
921 | * delay constructor execution. | |
922 | */ | |
923 | ret = handle_register_done(sock_info); | |
924 | assert(!ret); | |
925 | ust_unlock(); | |
926 | goto restart; | |
927 | } | |
928 | sock = sock_info->socket; | |
929 | ||
17dfb34b | 930 | ust_unlock(); |
46050b1a | 931 | |
d9e99d10 MD |
932 | for (;;) { |
933 | ssize_t len; | |
57773204 | 934 | struct ustcomm_ust_msg lum; |
d9e99d10 | 935 | |
57773204 | 936 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
937 | switch (len) { |
938 | case 0: /* orderly shutdown */ | |
7dd08bec | 939 | DBG("%s lttng-sessiond has performed an orderly shutdown", sock_info->name); |
8236ba10 | 940 | ust_lock(); |
d5e1fea6 | 941 | if (lttng_ust_comm_should_quit) { |
d5e1fea6 MD |
942 | goto quit; |
943 | } | |
8236ba10 MD |
944 | /* |
945 | * Either sessiond has shutdown or refused us by closing the socket. | |
946 | * In either case, we don't want to delay construction execution, | |
947 | * and we need to wait before retry. | |
948 | */ | |
949 | prev_connect_failed = 1; | |
950 | /* | |
951 | * If we cannot register to the sessiond daemon, don't | |
952 | * delay constructor execution. | |
953 | */ | |
954 | ret = handle_register_done(sock_info); | |
955 | assert(!ret); | |
956 | ust_unlock(); | |
d9e99d10 | 957 | goto end; |
e7723462 | 958 | case sizeof(lum): |
74d81a6c | 959 | print_cmd(lum.cmd, lum.handle); |
11ff9c7d | 960 | ret = handle_message(sock_info, sock, &lum); |
7bc53e94 | 961 | if (ret) { |
11ff9c7d | 962 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
963 | } |
964 | continue; | |
7bc53e94 MD |
965 | default: |
966 | if (len < 0) { | |
967 | DBG("Receive failed from lttng-sessiond with errno %d", (int) -len); | |
968 | } else { | |
969 | DBG("incorrect message size (%s socket): %zd", sock_info->name, len); | |
970 | } | |
971 | if (len == -ECONNRESET) { | |
972 | DBG("%s remote end closed connection", sock_info->name); | |
d9e99d10 MD |
973 | goto end; |
974 | } | |
975 | goto end; | |
d9e99d10 MD |
976 | } |
977 | ||
978 | } | |
979 | end: | |
f59ed768 | 980 | ust_lock(); |
d5e1fea6 | 981 | if (lttng_ust_comm_should_quit) { |
d5e1fea6 MD |
982 | goto quit; |
983 | } | |
f59ed768 MD |
984 | /* Cleanup socket handles before trying to reconnect */ |
985 | lttng_ust_objd_table_owner_cleanup(sock_info); | |
986 | ust_unlock(); | |
9eb62b9c | 987 | goto restart; /* try to reconnect */ |
e33f3265 | 988 | |
1ea11eab | 989 | quit: |
e33f3265 MD |
990 | sock_info->thread_active = 0; |
991 | ust_unlock(); | |
d9e99d10 MD |
992 | return NULL; |
993 | } | |
994 | ||
cf12a773 MD |
995 | /* |
996 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
997 | */ | |
11ff9c7d MD |
998 | static |
999 | int get_timeout(struct timespec *constructor_timeout) | |
1000 | { | |
cf12a773 MD |
1001 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
1002 | char *str_delay; | |
11ff9c7d MD |
1003 | int ret; |
1004 | ||
69400ac4 | 1005 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
1006 | if (str_delay) { |
1007 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
1008 | } | |
1009 | ||
1010 | switch (constructor_delay_ms) { | |
1011 | case -1:/* fall-through */ | |
1012 | case 0: | |
1013 | return constructor_delay_ms; | |
1014 | default: | |
1015 | break; | |
1016 | } | |
1017 | ||
1018 | /* | |
1019 | * If we are unable to find the current time, don't wait. | |
1020 | */ | |
1021 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
1022 | if (ret) { | |
1023 | return -1; | |
1024 | } | |
95259bd0 MD |
1025 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
1026 | constructor_timeout->tv_nsec += | |
1027 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
1028 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
1029 | constructor_timeout->tv_sec++; | |
1030 | constructor_timeout->tv_nsec -= 1000000000UL; | |
1031 | } | |
cf12a773 | 1032 | return 1; |
11ff9c7d | 1033 | } |
d9e99d10 | 1034 | |
2691221a MD |
1035 | /* |
1036 | * sessiond monitoring thread: monitor presence of global and per-user | |
1037 | * sessiond by polling the application common named pipe. | |
1038 | */ | |
edaa1431 | 1039 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 1040 | { |
11ff9c7d | 1041 | struct timespec constructor_timeout; |
ae6a58bf | 1042 | sigset_t sig_all_blocked, orig_parent_mask; |
1879f67f | 1043 | pthread_attr_t thread_attr; |
cf12a773 | 1044 | int timeout_mode; |
2691221a MD |
1045 | int ret; |
1046 | ||
edaa1431 MD |
1047 | if (uatomic_xchg(&initialized, 1) == 1) |
1048 | return; | |
1049 | ||
eddd8d5d MD |
1050 | /* |
1051 | * Fixup interdependency between TLS fixup mutex (which happens | |
1052 | * to be the dynamic linker mutex) and ust_lock, taken within | |
1053 | * the ust lock. | |
1054 | */ | |
f645cfa7 | 1055 | lttng_fixup_ringbuffer_tls(); |
4158a15a | 1056 | lttng_fixup_vtid_tls(); |
a903623f | 1057 | lttng_fixup_nest_count_tls(); |
009745db | 1058 | lttng_fixup_procname_tls(); |
eddd8d5d | 1059 | |
edaa1431 MD |
1060 | /* |
1061 | * We want precise control over the order in which we construct | |
1062 | * our sub-libraries vs starting to receive commands from | |
1063 | * sessiond (otherwise leading to errors when trying to create | |
1064 | * sessiond before the init functions are completed). | |
1065 | */ | |
2691221a | 1066 | init_usterr(); |
edaa1431 | 1067 | init_tracepoint(); |
7dd08bec MD |
1068 | lttng_ring_buffer_metadata_client_init(); |
1069 | lttng_ring_buffer_client_overwrite_init(); | |
1070 | lttng_ring_buffer_client_discard_init(); | |
2691221a | 1071 | |
cf12a773 | 1072 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 1073 | |
95259bd0 | 1074 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
1075 | assert(!ret); |
1076 | ||
8d20bf54 | 1077 | ret = setup_local_apps(); |
2691221a | 1078 | if (ret) { |
9ec6895c | 1079 | DBG("local apps setup returned %d", ret); |
2691221a | 1080 | } |
ae6a58bf WP |
1081 | |
1082 | /* A new thread created by pthread_create inherits the signal mask | |
1083 | * from the parent. To avoid any signal being received by the | |
1084 | * listener thread, we block all signals temporarily in the parent, | |
1085 | * while we create the listener thread. | |
1086 | */ | |
1087 | sigfillset(&sig_all_blocked); | |
1088 | ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask); | |
1089 | if (ret) { | |
d94d802c | 1090 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
1091 | } |
1092 | ||
1879f67f MG |
1093 | ret = pthread_attr_init(&thread_attr); |
1094 | if (ret) { | |
1095 | ERR("pthread_attr_init: %s", strerror(ret)); | |
1096 | } | |
1097 | ret = pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED); | |
1098 | if (ret) { | |
1099 | ERR("pthread_attr_setdetachstate: %s", strerror(ret)); | |
1100 | } | |
1101 | ||
e33f3265 | 1102 | ust_lock(); |
1879f67f | 1103 | ret = pthread_create(&global_apps.ust_listener, &thread_attr, |
dde70ea0 | 1104 | ust_listener_thread, &global_apps); |
d94d802c MD |
1105 | if (ret) { |
1106 | ERR("pthread_create global: %s", strerror(ret)); | |
1107 | } | |
e33f3265 MD |
1108 | global_apps.thread_active = 1; |
1109 | ust_unlock(); | |
1110 | ||
8d20bf54 | 1111 | if (local_apps.allowed) { |
e33f3265 | 1112 | ust_lock(); |
1879f67f | 1113 | ret = pthread_create(&local_apps.ust_listener, &thread_attr, |
dde70ea0 | 1114 | ust_listener_thread, &local_apps); |
d94d802c MD |
1115 | if (ret) { |
1116 | ERR("pthread_create local: %s", strerror(ret)); | |
1117 | } | |
e33f3265 MD |
1118 | local_apps.thread_active = 1; |
1119 | ust_unlock(); | |
8d20bf54 MD |
1120 | } else { |
1121 | handle_register_done(&local_apps); | |
1122 | } | |
1879f67f MG |
1123 | ret = pthread_attr_destroy(&thread_attr); |
1124 | if (ret) { | |
1125 | ERR("pthread_attr_destroy: %s", strerror(ret)); | |
1126 | } | |
8d20bf54 | 1127 | |
ae6a58bf WP |
1128 | /* Restore original signal mask in parent */ |
1129 | ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL); | |
1130 | if (ret) { | |
d94d802c | 1131 | ERR("pthread_sigmask: %s", strerror(ret)); |
ae6a58bf WP |
1132 | } |
1133 | ||
cf12a773 MD |
1134 | switch (timeout_mode) { |
1135 | case 1: /* timeout wait */ | |
95259bd0 MD |
1136 | do { |
1137 | ret = sem_timedwait(&constructor_wait, | |
1138 | &constructor_timeout); | |
1139 | } while (ret < 0 && errno == EINTR); | |
cf12a773 | 1140 | if (ret < 0 && errno == ETIMEDOUT) { |
7dd08bec | 1141 | ERR("Timed out waiting for lttng-sessiond"); |
cf12a773 MD |
1142 | } else { |
1143 | assert(!ret); | |
1144 | } | |
1145 | break; | |
7b766b16 | 1146 | case -1:/* wait forever */ |
95259bd0 MD |
1147 | do { |
1148 | ret = sem_wait(&constructor_wait); | |
1149 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 1150 | assert(!ret); |
cf12a773 | 1151 | break; |
7b766b16 | 1152 | case 0: /* no timeout */ |
cf12a773 | 1153 | break; |
11ff9c7d | 1154 | } |
2691221a MD |
1155 | } |
1156 | ||
17dfb34b MD |
1157 | static |
1158 | void lttng_ust_cleanup(int exiting) | |
1159 | { | |
efe0de09 | 1160 | cleanup_sock_info(&global_apps, exiting); |
17dfb34b | 1161 | if (local_apps.allowed) { |
efe0de09 | 1162 | cleanup_sock_info(&local_apps, exiting); |
17dfb34b | 1163 | } |
efe0de09 MD |
1164 | /* |
1165 | * The teardown in this function all affect data structures | |
1166 | * accessed under the UST lock by the listener thread. This | |
1167 | * lock, along with the lttng_ust_comm_should_quit flag, ensure | |
1168 | * that none of these threads are accessing this data at this | |
1169 | * point. | |
1170 | */ | |
17dfb34b | 1171 | lttng_ust_abi_exit(); |
003fedf4 | 1172 | lttng_ust_events_exit(); |
7dd08bec MD |
1173 | lttng_ring_buffer_client_discard_exit(); |
1174 | lttng_ring_buffer_client_overwrite_exit(); | |
1175 | lttng_ring_buffer_metadata_client_exit(); | |
17dfb34b MD |
1176 | exit_tracepoint(); |
1177 | if (!exiting) { | |
1178 | /* Reinitialize values for fork */ | |
1179 | sem_count = 2; | |
1180 | lttng_ust_comm_should_quit = 0; | |
1181 | initialized = 0; | |
1182 | } | |
1183 | } | |
1184 | ||
edaa1431 | 1185 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
1186 | { |
1187 | int ret; | |
1188 | ||
9eb62b9c MD |
1189 | /* |
1190 | * Using pthread_cancel here because: | |
1191 | * A) we don't want to hang application teardown. | |
1192 | * B) the thread is not allocating any resource. | |
1193 | */ | |
1ea11eab MD |
1194 | |
1195 | /* | |
1196 | * Require the communication thread to quit. Synchronize with | |
1197 | * mutexes to ensure it is not in a mutex critical section when | |
1198 | * pthread_cancel is later called. | |
1199 | */ | |
17dfb34b | 1200 | ust_lock(); |
1ea11eab | 1201 | lttng_ust_comm_should_quit = 1; |
1ea11eab | 1202 | |
f5f94532 | 1203 | /* cancel threads */ |
e33f3265 MD |
1204 | if (global_apps.thread_active) { |
1205 | ret = pthread_cancel(global_apps.ust_listener); | |
1206 | if (ret) { | |
1207 | ERR("Error cancelling global ust listener thread: %s", | |
1208 | strerror(ret)); | |
1209 | } else { | |
1210 | global_apps.thread_active = 0; | |
1211 | } | |
2691221a | 1212 | } |
e33f3265 | 1213 | if (local_apps.thread_active) { |
8d20bf54 MD |
1214 | ret = pthread_cancel(local_apps.ust_listener); |
1215 | if (ret) { | |
d94d802c MD |
1216 | ERR("Error cancelling local ust listener thread: %s", |
1217 | strerror(ret)); | |
e33f3265 MD |
1218 | } else { |
1219 | local_apps.thread_active = 0; | |
8d20bf54 | 1220 | } |
8d20bf54 | 1221 | } |
e33f3265 MD |
1222 | ust_unlock(); |
1223 | ||
efe0de09 MD |
1224 | /* |
1225 | * Do NOT join threads: use of sys_futex makes it impossible to | |
1226 | * join the threads without using async-cancel, but async-cancel | |
1227 | * is delivered by a signal, which could hit the target thread | |
1228 | * anywhere in its code path, including while the ust_lock() is | |
1229 | * held, causing a deadlock for the other thread. Let the OS | |
1230 | * cleanup the threads if there are stalled in a syscall. | |
1231 | */ | |
17dfb34b | 1232 | lttng_ust_cleanup(1); |
2691221a | 1233 | } |
e822f505 MD |
1234 | |
1235 | /* | |
1236 | * We exclude the worker threads across fork and clone (except | |
1237 | * CLONE_VM), because these system calls only keep the forking thread | |
1238 | * running in the child. Therefore, we don't want to call fork or clone | |
1239 | * in the middle of an tracepoint or ust tracing state modification. | |
1240 | * Holding this mutex protects these structures across fork and clone. | |
1241 | */ | |
b728d87e | 1242 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
1243 | { |
1244 | /* | |
1245 | * Disable signals. This is to avoid that the child intervenes | |
1246 | * before it is properly setup for tracing. It is safer to | |
1247 | * disable all signals, because then we know we are not breaking | |
1248 | * anything by restoring the original mask. | |
1249 | */ | |
1250 | sigset_t all_sigs; | |
1251 | int ret; | |
1252 | ||
8c90a710 | 1253 | if (URCU_TLS(lttng_ust_nest_count)) |
e8508a49 | 1254 | return; |
e822f505 MD |
1255 | /* Disable signals */ |
1256 | sigfillset(&all_sigs); | |
b728d87e | 1257 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
1258 | if (ret == -1) { |
1259 | PERROR("sigprocmask"); | |
1260 | } | |
17dfb34b | 1261 | ust_lock(); |
e822f505 MD |
1262 | rcu_bp_before_fork(); |
1263 | } | |
1264 | ||
b728d87e | 1265 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
1266 | { |
1267 | int ret; | |
1268 | ||
17dfb34b MD |
1269 | DBG("process %d", getpid()); |
1270 | ust_unlock(); | |
e822f505 | 1271 | /* Restore signals */ |
23c8854a | 1272 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
1273 | if (ret == -1) { |
1274 | PERROR("sigprocmask"); | |
1275 | } | |
1276 | } | |
1277 | ||
b728d87e | 1278 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 1279 | { |
8c90a710 | 1280 | if (URCU_TLS(lttng_ust_nest_count)) |
e8508a49 | 1281 | return; |
17dfb34b | 1282 | DBG("process %d", getpid()); |
e822f505 MD |
1283 | rcu_bp_after_fork_parent(); |
1284 | /* Release mutexes and reenable signals */ | |
b728d87e | 1285 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
1286 | } |
1287 | ||
17dfb34b MD |
1288 | /* |
1289 | * After fork, in the child, we need to cleanup all the leftover state, | |
1290 | * except the worker thread which already magically disappeared thanks | |
1291 | * to the weird Linux fork semantics. After tyding up, we call | |
1292 | * lttng_ust_init() again to start over as a new PID. | |
1293 | * | |
1294 | * This is meant for forks() that have tracing in the child between the | |
1295 | * fork and following exec call (if there is any). | |
1296 | */ | |
b728d87e | 1297 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 1298 | { |
8c90a710 | 1299 | if (URCU_TLS(lttng_ust_nest_count)) |
e8508a49 | 1300 | return; |
17dfb34b | 1301 | DBG("process %d", getpid()); |
e822f505 MD |
1302 | /* Release urcu mutexes */ |
1303 | rcu_bp_after_fork_child(); | |
17dfb34b | 1304 | lttng_ust_cleanup(0); |
a93bfc45 | 1305 | lttng_context_vtid_reset(); |
e822f505 | 1306 | /* Release mutexes and reenable signals */ |
b728d87e | 1307 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1308 | lttng_ust_init(); |
e822f505 | 1309 | } |