Commit | Line | Data |
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1ce86c9a JD |
1 | /* |
2 | * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca> | |
3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
82a3637f DG |
7 | * as published by the Free Software Foundation; only version 2 |
8 | * of the License. | |
1ce86c9a JD |
9 | * |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
18 | */ | |
19 | ||
20 | #define _GNU_SOURCE | |
1e307fab | 21 | #include <assert.h> |
1ce86c9a JD |
22 | #include <fcntl.h> |
23 | #include <poll.h> | |
24 | #include <pthread.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | #include <sys/mman.h> | |
28 | #include <sys/socket.h> | |
29 | #include <sys/types.h> | |
30 | #include <unistd.h> | |
6533b585 | 31 | |
1e307fab DG |
32 | #include <lttng-kernel-ctl.h> |
33 | #include <lttng-sessiond-comm.h> | |
6533b585 | 34 | #include <lttng/lttng-kconsumerd.h> |
1e307fab | 35 | #include <lttngerr.h> |
1ce86c9a | 36 | |
6533b585 | 37 | static struct lttng_kconsumerd_global_data { |
242cd187 MD |
38 | /* |
39 | * kconsumerd_data.lock protects kconsumerd_data.fd_list, | |
6533b585 DG |
40 | * kconsumerd_data.fds_count, and kconsumerd_data.need_update. It ensures |
41 | * the count matches the number of items in the fd_list. It ensures the | |
42 | * list updates *always* trigger an fd_array update (therefore need to make | |
43 | * list update vs kconsumerd_data.need_update flag update atomic, and also | |
44 | * flag read, fd array and flag clear atomic). | |
242cd187 MD |
45 | */ |
46 | pthread_mutex_t lock; | |
47 | /* | |
6533b585 | 48 | * Number of element for the list below. Protected by kconsumerd_data.lock. |
242cd187 MD |
49 | */ |
50 | unsigned int fds_count; | |
51 | /* | |
6533b585 | 52 | * List of FDs. Protected by kconsumerd_data.lock. |
242cd187 | 53 | */ |
6533b585 | 54 | struct lttng_kconsumerd_fd_list fd_list; |
242cd187 | 55 | /* |
6533b585 DG |
56 | * Flag specifying if the local array of FDs needs update in the poll |
57 | * function. Protected by kconsumerd_data.lock. | |
242cd187 MD |
58 | */ |
59 | unsigned int need_update; | |
60 | } kconsumerd_data = { | |
61 | .fd_list.head = CDS_LIST_HEAD_INIT(kconsumerd_data.fd_list.head), | |
cb040cc1 JD |
62 | .fds_count = 0, |
63 | .need_update = 1, | |
1ce86c9a JD |
64 | }; |
65 | ||
6533b585 | 66 | /* timeout parameter, to control the polling thread grace period. */ |
1ce86c9a JD |
67 | static int kconsumerd_poll_timeout = -1; |
68 | ||
3dcd2721 | 69 | /* |
6533b585 DG |
70 | * Flag to inform the polling thread to quit when all fd hung up. Updated by |
71 | * the kconsumerd_thread_receive_fds when it notices that all fds has hung up. | |
72 | * Also updated by the signal handler (kconsumerd_should_exit()). Read by the | |
73 | * polling threads. | |
3dcd2721 MD |
74 | */ |
75 | static volatile int kconsumerd_quit = 0; | |
1ce86c9a JD |
76 | |
77 | /* | |
6533b585 DG |
78 | * Find a session fd in the global list. The kconsumerd_data.lock must be |
79 | * locked during this call. | |
38079a1b | 80 | * |
6533b585 | 81 | * Return 1 if found else 0. |
38079a1b DG |
82 | */ |
83 | static int kconsumerd_find_session_fd(int fd) | |
84 | { | |
6533b585 | 85 | struct lttng_kconsumerd_fd *iter; |
38079a1b | 86 | |
242cd187 | 87 | cds_list_for_each_entry(iter, &kconsumerd_data.fd_list.head, list) { |
38079a1b DG |
88 | if (iter->sessiond_fd == fd) { |
89 | DBG("Duplicate session fd %d", fd); | |
38079a1b DG |
90 | return 1; |
91 | } | |
92 | } | |
38079a1b DG |
93 | |
94 | return 0; | |
95 | } | |
96 | ||
1ce86c9a | 97 | /* |
6533b585 | 98 | * Remove a fd from the global list protected by a mutex. |
1ce86c9a | 99 | */ |
6533b585 | 100 | static void kconsumerd_del_fd(struct lttng_kconsumerd_fd *lcf) |
1ce86c9a | 101 | { |
8b270bdb | 102 | int ret; |
242cd187 | 103 | pthread_mutex_lock(&kconsumerd_data.lock); |
1ce86c9a | 104 | cds_list_del(&lcf->list); |
242cd187 MD |
105 | if (kconsumerd_data.fds_count > 0) { |
106 | kconsumerd_data.fds_count--; | |
1ce86c9a | 107 | if (lcf != NULL) { |
8b270bdb JD |
108 | if (lcf->mmap_base != NULL) { |
109 | ret = munmap(lcf->mmap_base, lcf->mmap_len); | |
110 | if (ret != 0) { | |
111 | perror("munmap"); | |
112 | } | |
113 | } | |
cb040cc1 JD |
114 | if (lcf->out_fd != 0) { |
115 | close(lcf->out_fd); | |
116 | } | |
1ce86c9a JD |
117 | close(lcf->consumerd_fd); |
118 | free(lcf); | |
119 | lcf = NULL; | |
120 | } | |
121 | } | |
242cd187 MD |
122 | kconsumerd_data.need_update = 1; |
123 | pthread_mutex_unlock(&kconsumerd_data.lock); | |
1ce86c9a JD |
124 | } |
125 | ||
126 | /* | |
5348b470 JD |
127 | * Create a struct lttcomm_kconsumerd_msg from the |
128 | * information received on the receiving socket | |
1ce86c9a | 129 | */ |
5348b470 JD |
130 | struct lttng_kconsumerd_fd *kconsumerd_allocate_fd( |
131 | struct lttcomm_kconsumerd_msg *buf, | |
6533b585 | 132 | int consumerd_fd) |
1ce86c9a | 133 | { |
6533b585 | 134 | struct lttng_kconsumerd_fd *tmp_fd; |
38079a1b | 135 | |
5348b470 JD |
136 | tmp_fd = malloc(sizeof(struct lttng_kconsumerd_fd)); |
137 | if (tmp_fd == NULL) { | |
138 | perror("malloc struct lttng_kconsumerd_fd"); | |
38079a1b DG |
139 | goto end; |
140 | } | |
1ce86c9a | 141 | |
1ce86c9a JD |
142 | tmp_fd->sessiond_fd = buf->fd; |
143 | tmp_fd->consumerd_fd = consumerd_fd; | |
144 | tmp_fd->state = buf->state; | |
145 | tmp_fd->max_sb_size = buf->max_sb_size; | |
cb040cc1 JD |
146 | tmp_fd->out_fd = 0; |
147 | tmp_fd->out_fd_offset = 0; | |
8b270bdb JD |
148 | tmp_fd->mmap_len = 0; |
149 | tmp_fd->mmap_base = NULL; | |
150 | tmp_fd->output = buf->output; | |
1ce86c9a | 151 | strncpy(tmp_fd->path_name, buf->path_name, PATH_MAX); |
99497cd0 | 152 | tmp_fd->path_name[PATH_MAX - 1] = '\0'; |
5348b470 JD |
153 | DBG("Allocated %s (sessiond_fd %d, consumerd_fd %d, out_fd %d)", |
154 | tmp_fd->path_name, tmp_fd->sessiond_fd, | |
155 | tmp_fd->consumerd_fd, tmp_fd->out_fd); | |
1ce86c9a | 156 | |
5348b470 JD |
157 | end: |
158 | return tmp_fd; | |
159 | } | |
1ce86c9a | 160 | |
5348b470 JD |
161 | /* |
162 | * Add a fd to the global list protected by a mutex. | |
163 | */ | |
164 | static int kconsumerd_add_fd(struct lttng_kconsumerd_fd *tmp_fd) | |
165 | { | |
166 | int ret; | |
8b270bdb | 167 | |
5348b470 JD |
168 | pthread_mutex_lock(&kconsumerd_data.lock); |
169 | /* Check if already exist */ | |
170 | ret = kconsumerd_find_session_fd(tmp_fd->sessiond_fd); | |
171 | if (ret == 1) { | |
172 | goto end; | |
8b270bdb | 173 | } |
242cd187 MD |
174 | cds_list_add(&tmp_fd->list, &kconsumerd_data.fd_list.head); |
175 | kconsumerd_data.fds_count++; | |
176 | kconsumerd_data.need_update = 1; | |
5348b470 | 177 | |
1ce86c9a | 178 | end: |
242cd187 | 179 | pthread_mutex_unlock(&kconsumerd_data.lock); |
1ce86c9a JD |
180 | return ret; |
181 | } | |
182 | ||
183 | /* | |
6533b585 | 184 | * Update a fd according to what we just received. |
1ce86c9a JD |
185 | */ |
186 | static void kconsumerd_change_fd_state(int sessiond_fd, | |
6533b585 | 187 | enum lttng_kconsumerd_fd_state state) |
1ce86c9a | 188 | { |
6533b585 | 189 | struct lttng_kconsumerd_fd *iter; |
0237248c | 190 | |
242cd187 MD |
191 | pthread_mutex_lock(&kconsumerd_data.lock); |
192 | cds_list_for_each_entry(iter, &kconsumerd_data.fd_list.head, list) { | |
1ce86c9a JD |
193 | if (iter->sessiond_fd == sessiond_fd) { |
194 | iter->state = state; | |
195 | break; | |
196 | } | |
197 | } | |
242cd187 MD |
198 | kconsumerd_data.need_update = 1; |
199 | pthread_mutex_unlock(&kconsumerd_data.lock); | |
1ce86c9a JD |
200 | } |
201 | ||
202 | /* | |
6533b585 DG |
203 | * Allocate the pollfd structure and the local view of the out fds to avoid |
204 | * doing a lookup in the linked list and concurrency issues when writing is | |
205 | * needed. Called with kconsumerd_data.lock held. | |
1ce86c9a | 206 | * |
6533b585 | 207 | * Returns the number of fds in the structures. |
1ce86c9a | 208 | */ |
6533b585 DG |
209 | static int kconsumerd_update_poll_array( |
210 | struct lttng_kconsumerd_local_data *ctx, struct pollfd **pollfd, | |
211 | struct lttng_kconsumerd_fd **local_kconsumerd_fd) | |
1ce86c9a | 212 | { |
6533b585 | 213 | struct lttng_kconsumerd_fd *iter; |
1ce86c9a JD |
214 | int i = 0; |
215 | ||
216 | DBG("Updating poll fd array"); | |
242cd187 | 217 | cds_list_for_each_entry(iter, &kconsumerd_data.fd_list.head, list) { |
1ce86c9a JD |
218 | if (iter->state == ACTIVE_FD) { |
219 | DBG("Active FD %d", iter->consumerd_fd); | |
220 | (*pollfd)[i].fd = iter->consumerd_fd; | |
221 | (*pollfd)[i].events = POLLIN | POLLPRI; | |
222 | local_kconsumerd_fd[i] = iter; | |
223 | i++; | |
224 | } | |
225 | } | |
226 | ||
227 | /* | |
6533b585 DG |
228 | * Insert the kconsumerd_poll_pipe at the end of the array and don't |
229 | * increment i so nb_fd is the number of real FD. | |
1ce86c9a | 230 | */ |
cb040cc1 | 231 | (*pollfd)[i].fd = ctx->kconsumerd_poll_pipe[0]; |
1ce86c9a | 232 | (*pollfd)[i].events = POLLIN; |
1ce86c9a JD |
233 | return i; |
234 | } | |
235 | ||
6533b585 DG |
236 | /* |
237 | * Receives an array of file descriptors and the associated structures | |
238 | * describing each fd (path name). | |
239 | * | |
240 | * Returns the size of received data | |
241 | */ | |
242 | static int kconsumerd_consumerd_recv_fd( | |
243 | struct lttng_kconsumerd_local_data *ctx, int sfd, | |
244 | struct pollfd *kconsumerd_sockpoll, int size, | |
245 | enum lttng_kconsumerd_command cmd_type) | |
246 | { | |
247 | struct iovec iov[1]; | |
248 | int ret = 0, i, tmp2; | |
249 | struct cmsghdr *cmsg; | |
250 | int nb_fd; | |
251 | char recv_fd[CMSG_SPACE(sizeof(int))]; | |
252 | struct lttcomm_kconsumerd_msg lkm; | |
5348b470 | 253 | struct lttng_kconsumerd_fd *new_fd; |
6533b585 DG |
254 | |
255 | /* the number of fds we are about to receive */ | |
256 | nb_fd = size / sizeof(struct lttcomm_kconsumerd_msg); | |
257 | ||
258 | /* | |
259 | * nb_fd is the number of fds we receive. One fd per recvmsg. | |
260 | */ | |
261 | for (i = 0; i < nb_fd; i++) { | |
262 | struct msghdr msg = { 0 }; | |
263 | ||
264 | /* Prepare to receive the structures */ | |
265 | iov[0].iov_base = &lkm; | |
266 | iov[0].iov_len = sizeof(lkm); | |
267 | msg.msg_iov = iov; | |
268 | msg.msg_iovlen = 1; | |
269 | ||
270 | msg.msg_control = recv_fd; | |
271 | msg.msg_controllen = sizeof(recv_fd); | |
272 | ||
273 | DBG("Waiting to receive fd"); | |
274 | if (lttng_kconsumerd_poll_socket(kconsumerd_sockpoll) < 0) { | |
275 | goto end; | |
276 | } | |
277 | ||
278 | if ((ret = recvmsg(sfd, &msg, 0)) < 0) { | |
279 | perror("recvmsg"); | |
280 | continue; | |
281 | } | |
282 | ||
283 | if (ret != (size / nb_fd)) { | |
284 | ERR("Received only %d, expected %d", ret, size); | |
285 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_ERROR_RECV_FD); | |
286 | goto end; | |
287 | } | |
288 | ||
289 | cmsg = CMSG_FIRSTHDR(&msg); | |
290 | if (!cmsg) { | |
291 | ERR("Invalid control message header"); | |
292 | ret = -1; | |
293 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_ERROR_RECV_FD); | |
294 | goto end; | |
295 | } | |
296 | ||
297 | /* if we received fds */ | |
298 | if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { | |
299 | switch (cmd_type) { | |
300 | case ADD_STREAM: | |
301 | DBG("kconsumerd_add_fd %s (%d)", lkm.path_name, | |
302 | ((int *) CMSG_DATA(cmsg))[0]); | |
303 | ||
5348b470 JD |
304 | new_fd = kconsumerd_allocate_fd(&lkm, ((int *) CMSG_DATA(cmsg))[0]); |
305 | if (new_fd == NULL) { | |
6533b585 DG |
306 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_OUTFD_ERROR); |
307 | goto end; | |
308 | } | |
5348b470 JD |
309 | |
310 | if (ctx->on_recv_fd != NULL) { | |
311 | ret = ctx->on_recv_fd(new_fd); | |
312 | if (ret == 0) { | |
313 | kconsumerd_add_fd(new_fd); | |
314 | } else if (ret < 0) { | |
315 | goto end; | |
316 | } | |
317 | } else { | |
318 | kconsumerd_add_fd(new_fd); | |
319 | } | |
6533b585 DG |
320 | break; |
321 | case UPDATE_STREAM: | |
5348b470 JD |
322 | if (ctx->on_update_fd != NULL) { |
323 | ret = ctx->on_update_fd(lkm.fd, lkm.state); | |
324 | if (ret == 0) { | |
325 | kconsumerd_change_fd_state(lkm.fd, lkm.state); | |
326 | } else if (ret < 0) { | |
327 | goto end; | |
328 | } | |
329 | } else { | |
330 | kconsumerd_change_fd_state(lkm.fd, lkm.state); | |
331 | } | |
6533b585 DG |
332 | break; |
333 | default: | |
334 | break; | |
335 | } | |
336 | /* signal the poll thread */ | |
337 | tmp2 = write(ctx->kconsumerd_poll_pipe[1], "4", 1); | |
338 | if (tmp2 < 0) { | |
339 | perror("write kconsumerd poll"); | |
340 | } | |
341 | } else { | |
342 | ERR("Didn't received any fd"); | |
343 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_ERROR_RECV_FD); | |
344 | ret = -1; | |
345 | goto end; | |
346 | } | |
347 | } | |
348 | ||
349 | end: | |
350 | return ret; | |
351 | } | |
352 | ||
353 | /* | |
354 | * Set the error socket. | |
355 | */ | |
356 | void lttng_kconsumerd_set_error_sock( | |
357 | struct lttng_kconsumerd_local_data *ctx, int sock) | |
358 | { | |
359 | ctx->kconsumerd_error_socket = sock; | |
360 | } | |
361 | ||
362 | /* | |
363 | * Set the command socket path. | |
364 | */ | |
365 | ||
366 | void lttng_kconsumerd_set_command_sock_path( | |
367 | struct lttng_kconsumerd_local_data *ctx, char *sock) | |
368 | { | |
369 | ctx->kconsumerd_command_sock_path = sock; | |
370 | } | |
1ce86c9a | 371 | |
92ab9ab6 JD |
372 | static void lttng_kconsumerd_sync_trace_file( |
373 | struct lttng_kconsumerd_fd *kconsumerd_fd, off_t orig_offset) | |
374 | { | |
375 | int outfd = kconsumerd_fd->out_fd; | |
376 | /* | |
377 | * This does a blocking write-and-wait on any page that belongs to the | |
378 | * subbuffer prior to the one we just wrote. | |
379 | * Don't care about error values, as these are just hints and ways to | |
380 | * limit the amount of page cache used. | |
381 | */ | |
382 | if (orig_offset >= kconsumerd_fd->max_sb_size) { | |
383 | sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size, | |
384 | kconsumerd_fd->max_sb_size, | |
385 | SYNC_FILE_RANGE_WAIT_BEFORE | |
386 | | SYNC_FILE_RANGE_WRITE | |
387 | | SYNC_FILE_RANGE_WAIT_AFTER); | |
388 | /* | |
389 | * Give hints to the kernel about how we access the file: | |
390 | * POSIX_FADV_DONTNEED : we won't re-access data in a near future after | |
391 | * we write it. | |
392 | * | |
393 | * We need to call fadvise again after the file grows because the | |
394 | * kernel does not seem to apply fadvise to non-existing parts of the | |
395 | * file. | |
396 | * | |
397 | * Call fadvise _after_ having waited for the page writeback to | |
398 | * complete because the dirty page writeback semantic is not well | |
399 | * defined. So it can be expected to lead to lower throughput in | |
400 | * streaming. | |
401 | */ | |
402 | posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size, | |
403 | kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED); | |
404 | } | |
405 | } | |
406 | ||
407 | ||
1ce86c9a | 408 | /* |
6533b585 | 409 | * Mmap the ring buffer, read it and write the data to the tracefile. |
1ce86c9a | 410 | * |
1ce86c9a JD |
411 | * Returns the number of bytes written |
412 | */ | |
6533b585 DG |
413 | int lttng_kconsumerd_on_read_subbuffer_mmap( |
414 | struct lttng_kconsumerd_local_data *ctx, | |
415 | struct lttng_kconsumerd_fd *kconsumerd_fd, unsigned long len) | |
1ce86c9a | 416 | { |
8b270bdb | 417 | unsigned long mmap_offset; |
1ce86c9a JD |
418 | long ret = 0; |
419 | off_t orig_offset = kconsumerd_fd->out_fd_offset; | |
420 | int fd = kconsumerd_fd->consumerd_fd; | |
421 | int outfd = kconsumerd_fd->out_fd; | |
422 | ||
1ce86c9a JD |
423 | /* get the offset inside the fd to mmap */ |
424 | ret = kernctl_get_mmap_read_offset(fd, &mmap_offset); | |
425 | if (ret != 0) { | |
426 | ret = errno; | |
427 | perror("kernctl_get_mmap_read_offset"); | |
428 | goto end; | |
429 | } | |
430 | ||
1ce86c9a | 431 | while (len > 0) { |
8b270bdb | 432 | ret = write(outfd, kconsumerd_fd->mmap_base + mmap_offset, len); |
1ce86c9a JD |
433 | if (ret >= len) { |
434 | len = 0; | |
435 | } else if (ret < 0) { | |
436 | ret = errno; | |
437 | perror("Error in file write"); | |
438 | goto end; | |
439 | } | |
440 | /* This won't block, but will start writeout asynchronously */ | |
441 | sync_file_range(outfd, kconsumerd_fd->out_fd_offset, ret, | |
442 | SYNC_FILE_RANGE_WRITE); | |
443 | kconsumerd_fd->out_fd_offset += ret; | |
444 | } | |
445 | ||
92ab9ab6 | 446 | lttng_kconsumerd_sync_trace_file(kconsumerd_fd, orig_offset); |
1ce86c9a | 447 | |
1ce86c9a JD |
448 | goto end; |
449 | ||
450 | end: | |
1ce86c9a JD |
451 | return ret; |
452 | } | |
453 | ||
454 | /* | |
1ce86c9a | 455 | * Splice the data from the ring buffer to the tracefile. |
6533b585 DG |
456 | * |
457 | * Returns the number of bytes spliced. | |
1ce86c9a | 458 | */ |
6533b585 DG |
459 | int lttng_kconsumerd_on_read_subbuffer_splice( |
460 | struct lttng_kconsumerd_local_data *ctx, | |
461 | struct lttng_kconsumerd_fd *kconsumerd_fd, unsigned long len) | |
1ce86c9a JD |
462 | { |
463 | long ret = 0; | |
464 | loff_t offset = 0; | |
465 | off_t orig_offset = kconsumerd_fd->out_fd_offset; | |
466 | int fd = kconsumerd_fd->consumerd_fd; | |
467 | int outfd = kconsumerd_fd->out_fd; | |
468 | ||
469 | while (len > 0) { | |
470 | DBG("splice chan to pipe offset %lu (fd : %d)", | |
471 | (unsigned long)offset, fd); | |
cb040cc1 | 472 | ret = splice(fd, &offset, ctx->kconsumerd_thread_pipe[1], NULL, len, |
1ce86c9a JD |
473 | SPLICE_F_MOVE | SPLICE_F_MORE); |
474 | DBG("splice chan to pipe ret %ld", ret); | |
475 | if (ret < 0) { | |
476 | ret = errno; | |
477 | perror("Error in relay splice"); | |
478 | goto splice_error; | |
479 | } | |
480 | ||
cb040cc1 | 481 | ret = splice(ctx->kconsumerd_thread_pipe[0], NULL, outfd, NULL, ret, |
1ce86c9a JD |
482 | SPLICE_F_MOVE | SPLICE_F_MORE); |
483 | DBG("splice pipe to file %ld", ret); | |
484 | if (ret < 0) { | |
485 | ret = errno; | |
486 | perror("Error in file splice"); | |
487 | goto splice_error; | |
488 | } | |
751667bd | 489 | len -= ret; |
1ce86c9a JD |
490 | /* This won't block, but will start writeout asynchronously */ |
491 | sync_file_range(outfd, kconsumerd_fd->out_fd_offset, ret, | |
492 | SYNC_FILE_RANGE_WRITE); | |
493 | kconsumerd_fd->out_fd_offset += ret; | |
494 | } | |
92ab9ab6 | 495 | lttng_kconsumerd_sync_trace_file(kconsumerd_fd, orig_offset); |
1ce86c9a | 496 | |
1ce86c9a JD |
497 | goto end; |
498 | ||
499 | splice_error: | |
500 | /* send the appropriate error description to sessiond */ | |
501 | switch(ret) { | |
502 | case EBADF: | |
6533b585 | 503 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_EBADF); |
1ce86c9a JD |
504 | break; |
505 | case EINVAL: | |
6533b585 | 506 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_EINVAL); |
1ce86c9a JD |
507 | break; |
508 | case ENOMEM: | |
6533b585 | 509 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_ENOMEM); |
1ce86c9a JD |
510 | break; |
511 | case ESPIPE: | |
6533b585 | 512 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_ESPIPE); |
1ce86c9a | 513 | break; |
1ce86c9a JD |
514 | } |
515 | ||
516 | end: | |
517 | return ret; | |
518 | } | |
519 | ||
92ab9ab6 JD |
520 | /* |
521 | * Take a snapshot for a specific fd | |
522 | * | |
523 | * Returns 0 on success, < 0 on error | |
524 | */ | |
525 | int lttng_kconsumerd_take_snapshot(struct lttng_kconsumerd_local_data *ctx, | |
526 | struct lttng_kconsumerd_fd *kconsumerd_fd) | |
527 | { | |
528 | int ret = 0; | |
529 | int infd = kconsumerd_fd->consumerd_fd; | |
530 | ||
531 | ret = kernctl_snapshot(infd); | |
532 | if (ret != 0) { | |
533 | ret = errno; | |
534 | perror("Getting sub-buffer snapshot."); | |
535 | } | |
536 | ||
537 | return ret; | |
538 | } | |
539 | ||
540 | /* | |
541 | * Get the produced position | |
542 | * | |
543 | * Returns 0 on success, < 0 on error | |
544 | */ | |
545 | int lttng_kconsumerd_get_produced_snapshot( | |
546 | struct lttng_kconsumerd_local_data *ctx, | |
547 | struct lttng_kconsumerd_fd *kconsumerd_fd, | |
548 | unsigned long *pos) | |
549 | { | |
550 | int ret; | |
551 | int infd = kconsumerd_fd->consumerd_fd; | |
552 | ||
553 | ret = kernctl_snapshot_get_produced(infd, pos); | |
554 | if (ret != 0) { | |
555 | ret = errno; | |
556 | perror("kernctl_snapshot_get_produced"); | |
557 | } | |
558 | ||
559 | return ret; | |
560 | } | |
561 | ||
4de84ad9 | 562 | /* |
6533b585 DG |
563 | * Poll on the should_quit pipe and the command socket return -1 on error and |
564 | * should exit, 0 if data is available on the command socket | |
4de84ad9 | 565 | */ |
6533b585 | 566 | int lttng_kconsumerd_poll_socket(struct pollfd *kconsumerd_sockpoll) |
4de84ad9 JD |
567 | { |
568 | int num_rdy; | |
569 | ||
570 | num_rdy = poll(kconsumerd_sockpoll, 2, -1); | |
571 | if (num_rdy == -1) { | |
572 | perror("Poll error"); | |
573 | goto exit; | |
574 | } | |
575 | if (kconsumerd_sockpoll[0].revents == POLLIN) { | |
576 | DBG("kconsumerd_should_quit wake up"); | |
577 | goto exit; | |
578 | } | |
579 | return 0; | |
580 | ||
581 | exit: | |
582 | return -1; | |
583 | } | |
584 | ||
1ce86c9a | 585 | /* |
6533b585 DG |
586 | * This thread polls the fds in the ltt_fd_list to consume the data and write |
587 | * it to tracefile if necessary. | |
1ce86c9a | 588 | */ |
6533b585 | 589 | void *lttng_kconsumerd_thread_poll_fds(void *data) |
1ce86c9a JD |
590 | { |
591 | int num_rdy, num_hup, high_prio, ret, i; | |
592 | struct pollfd *pollfd = NULL; | |
593 | /* local view of the fds */ | |
6533b585 | 594 | struct lttng_kconsumerd_fd **local_kconsumerd_fd = NULL; |
242cd187 | 595 | /* local view of kconsumerd_data.fds_count */ |
1ce86c9a JD |
596 | int nb_fd = 0; |
597 | char tmp; | |
598 | int tmp2; | |
6533b585 | 599 | struct lttng_kconsumerd_local_data *ctx = data; |
1ce86c9a | 600 | |
1ce86c9a | 601 | |
6533b585 | 602 | local_kconsumerd_fd = malloc(sizeof(struct lttng_kconsumerd_fd)); |
1ce86c9a JD |
603 | |
604 | while (1) { | |
605 | high_prio = 0; | |
606 | num_hup = 0; | |
607 | ||
608 | /* | |
609 | * the ltt_fd_list has been updated, we need to update our | |
610 | * local array as well | |
611 | */ | |
242cd187 MD |
612 | pthread_mutex_lock(&kconsumerd_data.lock); |
613 | if (kconsumerd_data.need_update) { | |
1ce86c9a JD |
614 | if (pollfd != NULL) { |
615 | free(pollfd); | |
616 | pollfd = NULL; | |
617 | } | |
618 | if (local_kconsumerd_fd != NULL) { | |
619 | free(local_kconsumerd_fd); | |
620 | local_kconsumerd_fd = NULL; | |
621 | } | |
0237248c | 622 | |
1ce86c9a | 623 | /* allocate for all fds + 1 for the kconsumerd_poll_pipe */ |
242cd187 | 624 | pollfd = malloc((kconsumerd_data.fds_count + 1) * sizeof(struct pollfd)); |
1ce86c9a JD |
625 | if (pollfd == NULL) { |
626 | perror("pollfd malloc"); | |
242cd187 | 627 | pthread_mutex_unlock(&kconsumerd_data.lock); |
1ce86c9a JD |
628 | goto end; |
629 | } | |
0237248c | 630 | |
1ce86c9a | 631 | /* allocate for all fds + 1 for the kconsumerd_poll_pipe */ |
242cd187 | 632 | local_kconsumerd_fd = malloc((kconsumerd_data.fds_count + 1) * |
6533b585 | 633 | sizeof(struct lttng_kconsumerd_fd)); |
1ce86c9a JD |
634 | if (local_kconsumerd_fd == NULL) { |
635 | perror("local_kconsumerd_fd malloc"); | |
242cd187 | 636 | pthread_mutex_unlock(&kconsumerd_data.lock); |
1ce86c9a JD |
637 | goto end; |
638 | } | |
cb040cc1 | 639 | ret = kconsumerd_update_poll_array(ctx, &pollfd, local_kconsumerd_fd); |
1ce86c9a JD |
640 | if (ret < 0) { |
641 | ERR("Error in allocating pollfd or local_outfds"); | |
6533b585 | 642 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_POLL_ERROR); |
242cd187 | 643 | pthread_mutex_unlock(&kconsumerd_data.lock); |
1ce86c9a JD |
644 | goto end; |
645 | } | |
646 | nb_fd = ret; | |
242cd187 | 647 | kconsumerd_data.need_update = 0; |
1ce86c9a | 648 | } |
242cd187 | 649 | pthread_mutex_unlock(&kconsumerd_data.lock); |
1ce86c9a JD |
650 | |
651 | /* poll on the array of fds */ | |
652 | DBG("polling on %d fd", nb_fd + 1); | |
653 | num_rdy = poll(pollfd, nb_fd + 1, kconsumerd_poll_timeout); | |
654 | DBG("poll num_rdy : %d", num_rdy); | |
655 | if (num_rdy == -1) { | |
656 | perror("Poll error"); | |
6533b585 | 657 | lttng_kconsumerd_send_error(ctx, KCONSUMERD_POLL_ERROR); |
1ce86c9a JD |
658 | goto end; |
659 | } else if (num_rdy == 0) { | |
660 | DBG("Polling thread timed out"); | |
661 | goto end; | |
662 | } | |
663 | ||
664 | /* No FDs and kconsumerd_quit, kconsumerd_cleanup the thread */ | |
665 | if (nb_fd == 0 && kconsumerd_quit == 1) { | |
666 | goto end; | |
667 | } | |
668 | ||
669 | /* | |
242cd187 MD |
670 | * If the kconsumerd_poll_pipe triggered poll go |
671 | * directly to the beginning of the loop to update the | |
672 | * array. We want to prioritize array update over | |
673 | * low-priority reads. | |
1ce86c9a | 674 | */ |
242cd187 | 675 | if (pollfd[nb_fd].revents == POLLIN) { |
1ce86c9a | 676 | DBG("kconsumerd_poll_pipe wake up"); |
cb040cc1 | 677 | tmp2 = read(ctx->kconsumerd_poll_pipe[0], &tmp, 1); |
f40799e8 DG |
678 | if (tmp2 < 0) { |
679 | perror("read kconsumerd poll"); | |
680 | } | |
1ce86c9a JD |
681 | continue; |
682 | } | |
683 | ||
684 | /* Take care of high priority channels first. */ | |
685 | for (i = 0; i < nb_fd; i++) { | |
686 | switch(pollfd[i].revents) { | |
687 | case POLLERR: | |
688 | ERR("Error returned in polling fd %d.", pollfd[i].fd); | |
689 | kconsumerd_del_fd(local_kconsumerd_fd[i]); | |
1ce86c9a JD |
690 | num_hup++; |
691 | break; | |
692 | case POLLHUP: | |
693 | DBG("Polling fd %d tells it has hung up.", pollfd[i].fd); | |
694 | kconsumerd_del_fd(local_kconsumerd_fd[i]); | |
1ce86c9a JD |
695 | num_hup++; |
696 | break; | |
697 | case POLLNVAL: | |
698 | ERR("Polling fd %d tells fd is not open.", pollfd[i].fd); | |
699 | kconsumerd_del_fd(local_kconsumerd_fd[i]); | |
1ce86c9a JD |
700 | num_hup++; |
701 | break; | |
702 | case POLLPRI: | |
703 | DBG("Urgent read on fd %d", pollfd[i].fd); | |
704 | high_prio = 1; | |
cb040cc1 | 705 | ret = ctx->on_buffer_ready(local_kconsumerd_fd[i]); |
1ce86c9a JD |
706 | /* it's ok to have an unavailable sub-buffer */ |
707 | if (ret == EAGAIN) { | |
708 | ret = 0; | |
709 | } | |
710 | break; | |
711 | } | |
712 | } | |
713 | ||
714 | /* If every buffer FD has hung up, we end the read loop here */ | |
715 | if (nb_fd > 0 && num_hup == nb_fd) { | |
716 | DBG("every buffer FD has hung up\n"); | |
717 | if (kconsumerd_quit == 1) { | |
718 | goto end; | |
719 | } | |
720 | continue; | |
721 | } | |
722 | ||
723 | /* Take care of low priority channels. */ | |
724 | if (high_prio == 0) { | |
725 | for (i = 0; i < nb_fd; i++) { | |
726 | if (pollfd[i].revents == POLLIN) { | |
727 | DBG("Normal read on fd %d", pollfd[i].fd); | |
cb040cc1 | 728 | ret = ctx->on_buffer_ready(local_kconsumerd_fd[i]); |
1ce86c9a JD |
729 | /* it's ok to have an unavailable subbuffer */ |
730 | if (ret == EAGAIN) { | |
731 | ret = 0; | |
732 | } | |
733 | } | |
734 | } | |
735 | } | |
736 | } | |
737 | end: | |
738 | DBG("polling thread exiting"); | |
739 | if (pollfd != NULL) { | |
740 | free(pollfd); | |
741 | pollfd = NULL; | |
742 | } | |
743 | if (local_kconsumerd_fd != NULL) { | |
744 | free(local_kconsumerd_fd); | |
745 | local_kconsumerd_fd = NULL; | |
746 | } | |
1ce86c9a JD |
747 | return NULL; |
748 | } | |
749 | ||
750 | /* | |
6533b585 | 751 | * Initialise the necessary environnement : |
cb040cc1 | 752 | * - create a new context |
4de84ad9 JD |
753 | * - create the poll_pipe |
754 | * - create the should_quit pipe (for signal handler) | |
cb040cc1 | 755 | * - create the thread pipe (for splice) |
6533b585 | 756 | * |
cb040cc1 JD |
757 | * Takes a function pointer as argument, this function is called when data is |
758 | * available on a buffer. This function is responsible to do the | |
759 | * kernctl_get_next_subbuf, read the data with mmap or splice depending on the | |
760 | * buffer configuration and then kernctl_put_next_subbuf at the end. | |
6533b585 | 761 | * |
cb040cc1 | 762 | * Returns a pointer to the new context or NULL on error. |
1ce86c9a | 763 | */ |
6533b585 | 764 | struct lttng_kconsumerd_local_data *lttng_kconsumerd_create( |
5348b470 JD |
765 | int (*buffer_ready)(struct lttng_kconsumerd_fd *kconsumerd_fd), |
766 | int (*recv_fd)(struct lttng_kconsumerd_fd *kconsumerd_fd), | |
767 | int (*update_fd)(int sessiond_fd, uint32_t state)) | |
1ce86c9a | 768 | { |
5348b470 | 769 | int ret, i; |
6533b585 | 770 | struct lttng_kconsumerd_local_data *ctx; |
4de84ad9 | 771 | |
6533b585 | 772 | ctx = malloc(sizeof(struct lttng_kconsumerd_local_data)); |
cb040cc1 JD |
773 | if (ctx == NULL) { |
774 | perror("allocating context"); | |
5348b470 | 775 | goto error; |
cb040cc1 JD |
776 | } |
777 | ||
35346445 | 778 | ctx->kconsumerd_error_socket = -1; |
5348b470 | 779 | /* assign the callbacks */ |
cb040cc1 | 780 | ctx->on_buffer_ready = buffer_ready; |
5348b470 JD |
781 | ctx->on_recv_fd = recv_fd; |
782 | ctx->on_update_fd = update_fd; | |
4de84ad9 | 783 | |
cb040cc1 | 784 | ret = pipe(ctx->kconsumerd_poll_pipe); |
4de84ad9 JD |
785 | if (ret < 0) { |
786 | perror("Error creating poll pipe"); | |
5348b470 | 787 | goto error_poll_pipe; |
4de84ad9 JD |
788 | } |
789 | ||
cb040cc1 | 790 | ret = pipe(ctx->kconsumerd_should_quit); |
4de84ad9 JD |
791 | if (ret < 0) { |
792 | perror("Error creating recv pipe"); | |
5348b470 | 793 | goto error_quit_pipe; |
cb040cc1 JD |
794 | } |
795 | ||
796 | ret = pipe(ctx->kconsumerd_thread_pipe); | |
797 | if (ret < 0) { | |
798 | perror("Error creating thread pipe"); | |
5348b470 | 799 | goto error_thread_pipe; |
4de84ad9 JD |
800 | } |
801 | ||
cb040cc1 | 802 | return ctx; |
5348b470 JD |
803 | |
804 | ||
805 | error_thread_pipe: | |
806 | for (i = 0; i < 2; i++) { | |
807 | int err; | |
808 | ||
809 | err = close(ctx->kconsumerd_should_quit[i]); | |
810 | assert(!err); | |
811 | } | |
812 | error_quit_pipe: | |
813 | for (i = 0; i < 2; i++) { | |
814 | int err; | |
815 | ||
816 | err = close(ctx->kconsumerd_poll_pipe[i]); | |
817 | assert(!err); | |
818 | } | |
819 | error_poll_pipe: | |
820 | free(ctx); | |
821 | error: | |
822 | return NULL; | |
cb040cc1 JD |
823 | } |
824 | ||
825 | /* | |
6533b585 | 826 | * Close all fds associated with the instance and free the context. |
cb040cc1 | 827 | */ |
6533b585 | 828 | void lttng_kconsumerd_destroy(struct lttng_kconsumerd_local_data *ctx) |
cb040cc1 JD |
829 | { |
830 | close(ctx->kconsumerd_error_socket); | |
831 | close(ctx->kconsumerd_thread_pipe[0]); | |
832 | close(ctx->kconsumerd_thread_pipe[1]); | |
833 | close(ctx->kconsumerd_poll_pipe[0]); | |
834 | close(ctx->kconsumerd_poll_pipe[1]); | |
835 | close(ctx->kconsumerd_should_quit[0]); | |
836 | close(ctx->kconsumerd_should_quit[1]); | |
837 | unlink(ctx->kconsumerd_command_sock_path); | |
838 | free(ctx); | |
839 | ctx = NULL; | |
1ce86c9a JD |
840 | } |
841 | ||
842 | /* | |
6533b585 DG |
843 | * This thread listens on the consumerd socket and receives the file |
844 | * descriptors from the session daemon. | |
1ce86c9a | 845 | */ |
6533b585 | 846 | void *lttng_kconsumerd_thread_receive_fds(void *data) |
1ce86c9a JD |
847 | { |
848 | int sock, client_socket, ret; | |
849 | struct lttcomm_kconsumerd_header tmp; | |
4de84ad9 | 850 | /* |
6533b585 DG |
851 | * structure to poll for incoming data on communication socket avoids |
852 | * making blocking sockets. | |
4de84ad9 JD |
853 | */ |
854 | struct pollfd kconsumerd_sockpoll[2]; | |
6533b585 | 855 | struct lttng_kconsumerd_local_data *ctx = data; |
4de84ad9 | 856 | |
1ce86c9a | 857 | |
cb040cc1 JD |
858 | DBG("Creating command socket %s", ctx->kconsumerd_command_sock_path); |
859 | unlink(ctx->kconsumerd_command_sock_path); | |
860 | client_socket = lttcomm_create_unix_sock(ctx->kconsumerd_command_sock_path); | |
1ce86c9a JD |
861 | if (client_socket < 0) { |
862 | ERR("Cannot create command socket"); | |
863 | goto end; | |
864 | } | |
865 | ||
866 | ret = lttcomm_listen_unix_sock(client_socket); | |
867 | if (ret < 0) { | |
868 | goto end; | |
869 | } | |
870 | ||
871 | DBG("Sending ready command to ltt-sessiond"); | |
6533b585 | 872 | ret = lttng_kconsumerd_send_error(ctx, KCONSUMERD_COMMAND_SOCK_READY); |
35346445 | 873 | /* return < 0 on error, but == 0 is not fatal */ |
1ce86c9a JD |
874 | if (ret < 0) { |
875 | ERR("Error sending ready command to ltt-sessiond"); | |
876 | goto end; | |
877 | } | |
878 | ||
4de84ad9 JD |
879 | ret = fcntl(client_socket, F_SETFL, O_NONBLOCK); |
880 | if (ret < 0) { | |
881 | perror("fcntl O_NONBLOCK"); | |
882 | goto end; | |
883 | } | |
884 | ||
885 | /* prepare the FDs to poll : to client socket and the should_quit pipe */ | |
cb040cc1 | 886 | kconsumerd_sockpoll[0].fd = ctx->kconsumerd_should_quit[0]; |
4de84ad9 JD |
887 | kconsumerd_sockpoll[0].events = POLLIN | POLLPRI; |
888 | kconsumerd_sockpoll[1].fd = client_socket; | |
889 | kconsumerd_sockpoll[1].events = POLLIN | POLLPRI; | |
890 | ||
6533b585 | 891 | if (lttng_kconsumerd_poll_socket(kconsumerd_sockpoll) < 0) { |
4de84ad9 JD |
892 | goto end; |
893 | } | |
894 | DBG("Connection on client_socket"); | |
895 | ||
1ce86c9a JD |
896 | /* Blocking call, waiting for transmission */ |
897 | sock = lttcomm_accept_unix_sock(client_socket); | |
898 | if (sock <= 0) { | |
899 | WARN("On accept"); | |
900 | goto end; | |
901 | } | |
4de84ad9 JD |
902 | ret = fcntl(sock, F_SETFL, O_NONBLOCK); |
903 | if (ret < 0) { | |
904 | perror("fcntl O_NONBLOCK"); | |
905 | goto end; | |
906 | } | |
907 | ||
908 | /* update the polling structure to poll on the established socket */ | |
909 | kconsumerd_sockpoll[1].fd = sock; | |
910 | kconsumerd_sockpoll[1].events = POLLIN | POLLPRI; | |
911 | ||
1ce86c9a | 912 | while (1) { |
6533b585 | 913 | if (lttng_kconsumerd_poll_socket(kconsumerd_sockpoll) < 0) { |
4de84ad9 JD |
914 | goto end; |
915 | } | |
916 | DBG("Incoming fds on sock"); | |
917 | ||
1ce86c9a JD |
918 | /* We first get the number of fd we are about to receive */ |
919 | ret = lttcomm_recv_unix_sock(sock, &tmp, | |
920 | sizeof(struct lttcomm_kconsumerd_header)); | |
921 | if (ret <= 0) { | |
922 | ERR("Communication interrupted on command socket"); | |
923 | goto end; | |
924 | } | |
925 | if (tmp.cmd_type == STOP) { | |
926 | DBG("Received STOP command"); | |
927 | goto end; | |
928 | } | |
3dcd2721 MD |
929 | if (kconsumerd_quit) { |
930 | DBG("kconsumerd_thread_receive_fds received quit from signal"); | |
931 | goto end; | |
932 | } | |
4de84ad9 | 933 | |
1ce86c9a | 934 | /* we received a command to add or update fds */ |
cb040cc1 | 935 | ret = kconsumerd_consumerd_recv_fd(ctx, sock, kconsumerd_sockpoll, |
4de84ad9 | 936 | tmp.payload_size, tmp.cmd_type); |
8b270bdb | 937 | if (ret < 0) { |
1ce86c9a JD |
938 | ERR("Receiving the FD, exiting"); |
939 | goto end; | |
940 | } | |
4de84ad9 | 941 | DBG("received fds on sock"); |
1ce86c9a JD |
942 | } |
943 | ||
944 | end: | |
945 | DBG("kconsumerd_thread_receive_fds exiting"); | |
946 | ||
947 | /* | |
948 | * when all fds have hung up, the polling thread | |
949 | * can exit cleanly | |
950 | */ | |
951 | kconsumerd_quit = 1; | |
952 | ||
953 | /* | |
954 | * 2s of grace period, if no polling events occur during | |
955 | * this period, the polling thread will exit even if there | |
956 | * are still open FDs (should not happen, but safety mechanism). | |
957 | */ | |
6533b585 | 958 | kconsumerd_poll_timeout = LTTNG_KCONSUMERD_POLL_GRACE_PERIOD; |
1ce86c9a JD |
959 | |
960 | /* wake up the polling thread */ | |
cb040cc1 | 961 | ret = write(ctx->kconsumerd_poll_pipe[1], "4", 1); |
1ce86c9a JD |
962 | if (ret < 0) { |
963 | perror("poll pipe write"); | |
964 | } | |
965 | return NULL; | |
966 | } | |
967 | ||
968 | /* | |
6533b585 DG |
969 | * Close all the tracefiles and stream fds, should be called when all instances |
970 | * are destroyed. | |
1ce86c9a | 971 | */ |
6533b585 | 972 | void lttng_kconsumerd_cleanup(void) |
1ce86c9a | 973 | { |
6533b585 | 974 | struct lttng_kconsumerd_fd *iter, *tmp; |
1ce86c9a | 975 | |
3dcd2721 MD |
976 | /* |
977 | * close all outfd. Called when there are no more threads | |
978 | * running (after joining on the threads), no need to protect | |
979 | * list iteration with mutex. | |
980 | */ | |
6533b585 DG |
981 | cds_list_for_each_entry_safe(iter, tmp, |
982 | &kconsumerd_data.fd_list.head, list) { | |
1ce86c9a JD |
983 | kconsumerd_del_fd(iter); |
984 | } | |
985 | } | |
986 | ||
3dcd2721 MD |
987 | /* |
988 | * Called from signal handler. | |
989 | */ | |
6533b585 | 990 | void lttng_kconsumerd_should_exit(struct lttng_kconsumerd_local_data *ctx) |
3dcd2721 | 991 | { |
4de84ad9 | 992 | int ret; |
3dcd2721 | 993 | kconsumerd_quit = 1; |
cb040cc1 | 994 | ret = write(ctx->kconsumerd_should_quit[1], "4", 1); |
f40799e8 DG |
995 | if (ret < 0) { |
996 | perror("write kconsumerd quit"); | |
997 | } | |
3dcd2721 MD |
998 | } |
999 | ||
1ce86c9a | 1000 | /* |
6533b585 | 1001 | * Send return code to the session daemon. |
35346445 | 1002 | * If the socket is not defined, we return 0, it is not a fatal error |
1ce86c9a | 1003 | */ |
6533b585 DG |
1004 | int lttng_kconsumerd_send_error( |
1005 | struct lttng_kconsumerd_local_data *ctx, int cmd) | |
1ce86c9a | 1006 | { |
cb040cc1 JD |
1007 | if (ctx->kconsumerd_error_socket > 0) { |
1008 | return lttcomm_send_unix_sock(ctx->kconsumerd_error_socket, &cmd, | |
1ce86c9a JD |
1009 | sizeof(enum lttcomm_sessiond_command)); |
1010 | } | |
1011 | ||
1012 | return 0; | |
1013 | } |