Fix: Consumer return value check after mmap/splice
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
CommitLineData
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1/*
2 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 *
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5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
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8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
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14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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17 */
18
19#define _GNU_SOURCE
20#include <assert.h>
f02e1e8a 21#include <lttng/ust-ctl.h>
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22#include <poll.h>
23#include <pthread.h>
24#include <stdlib.h>
25#include <string.h>
26#include <sys/mman.h>
27#include <sys/socket.h>
dbb5dfe6 28#include <sys/stat.h>
3bd1e081 29#include <sys/types.h>
77c7c900 30#include <inttypes.h>
3bd1e081 31#include <unistd.h>
0857097f 32
990570ed 33#include <common/common.h>
10a8a223 34#include <common/sessiond-comm/sessiond-comm.h>
00e2e675 35#include <common/relayd/relayd.h>
dbb5dfe6 36#include <common/compat/fcntl.h>
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37
38#include "ust-consumer.h"
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39
40extern struct lttng_consumer_global_data consumer_data;
41extern int consumer_poll_timeout;
42extern volatile int consumer_quit;
43
44/*
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45 * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
46 * compiled out, we isolate it in this library.
3bd1e081 47 */
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48int lttng_ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
49 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
3bd1e081 50{
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51 return ustctl_get_mmap_read_offset(handle, buf, off);
52};
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53
54/*
55 * Take a snapshot for a specific fd
56 *
57 * Returns 0 on success, < 0 on error
58 */
59int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
60 struct lttng_consumer_stream *stream)
61{
62 int ret = 0;
63
64 ret = ustctl_snapshot(stream->chan->handle, stream->buf);
65 if (ret != 0) {
87dc6a9c 66 errno = -ret;
4c462e79 67 PERROR("Getting sub-buffer snapshot.");
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68 }
69
70 return ret;
71}
72
73/*
74 * Get the produced position
75 *
76 * Returns 0 on success, < 0 on error
77 */
78int lttng_ustconsumer_get_produced_snapshot(
79 struct lttng_consumer_local_data *ctx,
80 struct lttng_consumer_stream *stream,
81 unsigned long *pos)
82{
83 int ret;
84
85 ret = ustctl_snapshot_get_produced(stream->chan->handle,
86 stream->buf, pos);
87 if (ret != 0) {
87dc6a9c 88 errno = -ret;
4c462e79 89 PERROR("kernctl_snapshot_get_produced");
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90 }
91
92 return ret;
93}
94
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95/*
96 * Receive command from session daemon and process it.
97 *
98 * Return 1 on success else a negative value or 0.
99 */
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100int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
101 int sock, struct pollfd *consumer_sockpoll)
102{
103 ssize_t ret;
104 struct lttcomm_consumer_msg msg;
105
106 ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
107 if (ret != sizeof(msg)) {
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108 DBG("Consumer received unexpected message size %zd (expects %zu)",
109 ret, sizeof(msg));
f73fabfd 110 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
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111 return ret;
112 }
113 if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
114 return -ENOENT;
115 }
116
3f8e211f 117 /* relayd needs RCU read-side lock */
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118 rcu_read_lock();
119
3bd1e081 120 switch (msg.cmd_type) {
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121 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
122 {
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123 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
124 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
125 &msg.u.relayd_sock.sock);
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126 goto end_nosignal;
127 }
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128 case LTTNG_CONSUMER_ADD_CHANNEL:
129 {
130 struct lttng_consumer_channel *new_channel;
131 int fds[1];
132 size_t nb_fd = 1;
133
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134 DBG("UST Consumer adding channel");
135
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136 /* block */
137 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
3f8e211f 138 rcu_read_unlock();
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139 return -EINTR;
140 }
141 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
142 if (ret != sizeof(fds)) {
f73fabfd 143 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
3f8e211f 144 rcu_read_unlock();
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145 return ret;
146 }
147
148 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
149
150 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
151 fds[0], -1,
152 msg.u.channel.mmap_len,
153 msg.u.channel.max_sb_size);
154 if (new_channel == NULL) {
f73fabfd 155 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
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156 goto end_nosignal;
157 }
158 if (ctx->on_recv_channel != NULL) {
159 ret = ctx->on_recv_channel(new_channel);
160 if (ret == 0) {
161 consumer_add_channel(new_channel);
162 } else if (ret < 0) {
163 goto end_nosignal;
164 }
165 } else {
166 consumer_add_channel(new_channel);
167 }
168 goto end_nosignal;
169 }
170 case LTTNG_CONSUMER_ADD_STREAM:
171 {
172 struct lttng_consumer_stream *new_stream;
173 int fds[2];
174 size_t nb_fd = 2;
00e2e675 175 struct consumer_relayd_sock_pair *relayd = NULL;
3bd1e081 176
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177 DBG("UST Consumer adding stream");
178
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179 /* block */
180 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
3f8e211f 181 rcu_read_unlock();
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182 return -EINTR;
183 }
184 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
185 if (ret != sizeof(fds)) {
f73fabfd 186 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
3f8e211f 187 rcu_read_unlock();
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188 return ret;
189 }
190
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191 DBG("consumer_add_stream chan %d stream %d",
192 msg.u.stream.channel_key,
193 msg.u.stream.stream_key);
194
d41f73b7 195 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
173af62f 196 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
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197 msg.u.stream.stream_key,
198 fds[0], fds[1],
199 msg.u.stream.state,
200 msg.u.stream.mmap_len,
201 msg.u.stream.output,
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202 msg.u.stream.path_name,
203 msg.u.stream.uid,
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204 msg.u.stream.gid,
205 msg.u.stream.net_index,
206 msg.u.stream.metadata_flag);
3bd1e081 207 if (new_stream == NULL) {
f73fabfd 208 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
3f8e211f 209 goto end_nosignal;
3bd1e081 210 }
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211
212 /* The stream is not metadata. Get relayd reference if exists. */
213 relayd = consumer_find_relayd(msg.u.stream.net_index);
214 if (relayd != NULL) {
215 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
216 /* Add stream on the relayd */
217 ret = relayd_add_stream(&relayd->control_sock,
218 msg.u.stream.name, msg.u.stream.path_name,
219 &new_stream->relayd_stream_id);
220 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
221 if (ret < 0) {
3f8e211f 222 goto end_nosignal;
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223 }
224 } else if (msg.u.stream.net_index != -1) {
225 ERR("Network sequence index %d unknown. Not adding stream.",
226 msg.u.stream.net_index);
227 free(new_stream);
3f8e211f 228 goto end_nosignal;
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229 }
230
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231 /* Send stream to the metadata thread */
232 if (new_stream->metadata_flag) {
233 if (ctx->on_recv_stream) {
234 ret = ctx->on_recv_stream(new_stream);
235 if (ret < 0) {
236 goto end_nosignal;
237 }
238 }
239
240 do {
241 ret = write(ctx->consumer_metadata_pipe[1], new_stream,
242 sizeof(struct lttng_consumer_stream));
243 } while (ret < 0 && errno == EINTR);
244 if (ret < 0) {
245 PERROR("write metadata pipe");
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246 }
247 } else {
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248 if (ctx->on_recv_stream) {
249 ret = ctx->on_recv_stream(new_stream);
250 if (ret < 0) {
251 goto end_nosignal;
252 }
253 }
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254 consumer_add_stream(new_stream);
255 }
00e2e675 256
77c7c900 257 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
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258 msg.u.stream.path_name, fds[0], fds[1],
259 new_stream->relayd_stream_id);
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260 break;
261 }
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262 case LTTNG_CONSUMER_DESTROY_RELAYD:
263 {
a6ba4fe1 264 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
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265 struct consumer_relayd_sock_pair *relayd;
266
a6ba4fe1 267 DBG("UST consumer destroying relayd %" PRIu64, index);
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268
269 /* Get relayd reference if exists. */
a6ba4fe1 270 relayd = consumer_find_relayd(index);
173af62f 271 if (relayd == NULL) {
a6ba4fe1 272 ERR("Unable to find relayd %" PRIu64, index);
3f8e211f 273 goto end_nosignal;
173af62f
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274 }
275
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276 /*
277 * Each relayd socket pair has a refcount of stream attached to it
278 * which tells if the relayd is still active or not depending on the
279 * refcount value.
280 *
281 * This will set the destroy flag of the relayd object and destroy it
282 * if the refcount reaches zero when called.
283 *
284 * The destroy can happen either here or when a stream fd hangs up.
285 */
286 consumer_flag_relayd_for_destroy(relayd);
173af62f 287
3f8e211f 288 goto end_nosignal;
173af62f 289 }
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290 case LTTNG_CONSUMER_UPDATE_STREAM:
291 {
3f8e211f 292 rcu_read_unlock();
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293 return -ENOSYS;
294#if 0
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295 if (ctx->on_update_stream != NULL) {
296 ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
297 if (ret == 0) {
298 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
299 } else if (ret < 0) {
300 goto end;
301 }
302 } else {
303 consumer_change_stream_state(msg.u.stream.stream_key,
304 msg.u.stream.state);
305 }
306 break;
3f8e211f 307#endif
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308 }
309 default:
310 break;
311 }
3f8e211f 312
04fdd819 313 /*
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314 * Wake-up the other end by writing a null byte in the pipe (non-blocking).
315 * Important note: Because writing into the pipe is non-blocking (and
316 * therefore we allow dropping wakeup data, as long as there is wakeup data
317 * present in the pipe buffer to wake up the other end), the other end
318 * should perform the following sequence for waiting:
319 *
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320 * 1) empty the pipe (reads).
321 * 2) perform update operation.
322 * 3) wait on the pipe (poll).
323 */
324 do {
325 ret = write(ctx->consumer_poll_pipe[1], "", 1);
6f94560a 326 } while (ret < 0 && errno == EINTR);
3bd1e081 327end_nosignal:
b0b335c8 328 rcu_read_unlock();
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329
330 /*
331 * Return 1 to indicate success since the 0 value can be a socket
332 * shutdown during the recv() or send() call.
333 */
334 return 1;
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335}
336
337int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
338{
13161846 339 struct lttng_ust_object_data obj;
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340
341 obj.handle = -1;
342 obj.shm_fd = chan->shm_fd;
343 obj.wait_fd = chan->wait_fd;
344 obj.memory_map_size = chan->mmap_len;
345 chan->handle = ustctl_map_channel(&obj);
346 if (!chan->handle) {
347 return -ENOMEM;
348 }
b5c5fc29 349 chan->wait_fd_is_copy = 1;
2c1dd183 350 chan->shm_fd = -1;
b5c5fc29 351
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352 return 0;
353}
354
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355void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
356{
357 ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
effcf122 358 stream->hangup_flush_done = 1;
d056b477
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359}
360
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361void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
362{
363 ustctl_unmap_channel(chan->handle);
364}
365
366int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
367{
13161846 368 struct lttng_ust_object_data obj;
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369 int ret;
370
371 obj.handle = -1;
372 obj.shm_fd = stream->shm_fd;
373 obj.wait_fd = stream->wait_fd;
374 obj.memory_map_size = stream->mmap_len;
375 ret = ustctl_add_stream(stream->chan->handle, &obj);
376 if (ret)
377 return ret;
378 stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
379 if (!stream->buf)
380 return -EBUSY;
2c1dd183
MD
381 /* ustctl_open_stream_read has closed the shm fd. */
382 stream->wait_fd_is_copy = 1;
383 stream->shm_fd = -1;
384
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385 stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
386 if (!stream->mmap_base) {
387 return -EINVAL;
388 }
ee77a7b0 389
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390 return 0;
391}
392
393void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
394{
395 ustctl_close_stream_read(stream->chan->handle, stream->buf);
396}
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397
398
399int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
400 struct lttng_consumer_local_data *ctx)
401{
1d4dfdef 402 unsigned long len, subbuf_size, padding;
d41f73b7
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403 int err;
404 long ret = 0;
405 struct lttng_ust_shm_handle *handle;
406 struct lttng_ust_lib_ring_buffer *buf;
407 char dummy;
408 ssize_t readlen;
409
410 DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
411 stream->wait_fd, stream->key);
412
413 /* We can consume the 1 byte written into the wait_fd by UST */
effcf122
MD
414 if (!stream->hangup_flush_done) {
415 do {
416 readlen = read(stream->wait_fd, &dummy, 1);
87dc6a9c 417 } while (readlen == -1 && errno == EINTR);
effcf122
MD
418 if (readlen == -1) {
419 ret = readlen;
420 goto end;
421 }
d41f73b7
MD
422 }
423
424 buf = stream->buf;
425 handle = stream->chan->handle;
426 /* Get the next subbuffer */
427 err = ustctl_get_next_subbuf(handle, buf);
428 if (err != 0) {
1d4dfdef 429 ret = err; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
d41f73b7
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430 /*
431 * This is a debug message even for single-threaded consumer,
432 * because poll() have more relaxed criterions than get subbuf,
433 * so get_subbuf may fail for short race windows where poll()
434 * would issue wakeups.
435 */
436 DBG("Reserving sub buffer failed (everything is normal, "
437 "it is due to concurrency)");
438 goto end;
439 }
440 assert(stream->output == LTTNG_EVENT_MMAP);
1d4dfdef 441 /* Get the full padded subbuffer size */
d41f73b7 442 err = ustctl_get_padded_subbuf_size(handle, buf, &len);
effcf122 443 assert(err == 0);
1d4dfdef
DG
444
445 /* Get subbuffer data size (without padding) */
446 err = ustctl_get_subbuf_size(handle, buf, &subbuf_size);
447 assert(err == 0);
448
449 /* Make sure we don't get a subbuffer size bigger than the padded */
450 assert(len >= subbuf_size);
451
452 padding = len - subbuf_size;
d41f73b7 453 /* write the subbuffer to the tracefile */
1d4dfdef 454 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
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455 /*
456 * The mmap operation should write subbuf_size amount of data when network
457 * streaming or the full padding (len) size when we are _not_ streaming.
458 */
459 if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
460 (ret != len && stream->net_seq_idx == -1)) {
d41f73b7 461 /*
91dfef6e
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462 * Display the error but continue processing to try to release the
463 * subbuffer
d41f73b7 464 */
91dfef6e
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465 ERR("Error writing to tracefile "
466 "(ret: %zd != len: %lu != subbuf_size: %lu)",
467 ret, len, subbuf_size);
468
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469 }
470 err = ustctl_put_next_subbuf(handle, buf);
effcf122 471 assert(err == 0);
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472end:
473 return ret;
474}
475
476int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
477{
478 int ret;
479
480 /* Opening the tracefile in write mode */
00e2e675 481 if (stream->path_name != NULL && stream->net_seq_idx == -1) {
e11d277b 482 ret = run_as_open(stream->path_name,
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483 O_WRONLY|O_CREAT|O_TRUNC,
484 S_IRWXU|S_IRWXG|S_IRWXO,
485 stream->uid, stream->gid);
d41f73b7
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486 if (ret < 0) {
487 ERR("Opening %s", stream->path_name);
4c462e79 488 PERROR("open");
d41f73b7
MD
489 goto error;
490 }
491 stream->out_fd = ret;
492 }
493
494 /* we return 0 to let the library handle the FD internally */
495 return 0;
496
497error:
498 return ret;
499}
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