f47c498777531ef6702b41d34b153abba3320e1e
[lttng-tools.git] / src / common / kernel-consumer / kernel-consumer.c
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 modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
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 *
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.
17 */
18
19 #define _GNU_SOURCE
20 #include <assert.h>
21 #include <poll.h>
22 #include <pthread.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sys/mman.h>
26 #include <sys/socket.h>
27 #include <sys/types.h>
28 #include <inttypes.h>
29 #include <unistd.h>
30 #include <sys/stat.h>
31
32 #include <common/common.h>
33 #include <common/kernel-ctl/kernel-ctl.h>
34 #include <common/sessiond-comm/sessiond-comm.h>
35 #include <common/sessiond-comm/relayd.h>
36 #include <common/compat/fcntl.h>
37 #include <common/pipe.h>
38 #include <common/relayd/relayd.h>
39 #include <common/utils.h>
40
41 #include "kernel-consumer.h"
42
43 extern struct lttng_consumer_global_data consumer_data;
44 extern int consumer_poll_timeout;
45 extern volatile int consumer_quit;
46
47 /*
48 * Take a snapshot for a specific fd
49 *
50 * Returns 0 on success, < 0 on error
51 */
52 int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream *stream)
53 {
54 int ret = 0;
55 int infd = stream->wait_fd;
56
57 ret = kernctl_snapshot(infd);
58 if (ret != 0) {
59 errno = -ret;
60 perror("Getting sub-buffer snapshot.");
61 }
62
63 return ret;
64 }
65
66 /*
67 * Get the produced position
68 *
69 * Returns 0 on success, < 0 on error
70 */
71 int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
72 unsigned long *pos)
73 {
74 int ret;
75 int infd = stream->wait_fd;
76
77 ret = kernctl_snapshot_get_produced(infd, pos);
78 if (ret != 0) {
79 errno = -ret;
80 perror("kernctl_snapshot_get_produced");
81 }
82
83 return ret;
84 }
85
86 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
87 int sock, struct pollfd *consumer_sockpoll)
88 {
89 ssize_t ret;
90 enum lttng_error_code ret_code = LTTNG_OK;
91 struct lttcomm_consumer_msg msg;
92
93 ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
94 if (ret != sizeof(msg)) {
95 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
96 return ret;
97 }
98 if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
99 /*
100 * Notify the session daemon that the command is completed.
101 *
102 * On transport layer error, the function call will print an error
103 * message so handling the returned code is a bit useless since we
104 * return an error code anyway.
105 */
106 (void) consumer_send_status_msg(sock, ret_code);
107 return -ENOENT;
108 }
109
110 /* relayd needs RCU read-side protection */
111 rcu_read_lock();
112
113 switch (msg.cmd_type) {
114 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
115 {
116 /* Session daemon status message are handled in the following call. */
117 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
118 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
119 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id);
120 goto end_nosignal;
121 }
122 case LTTNG_CONSUMER_ADD_CHANNEL:
123 {
124 struct lttng_consumer_channel *new_channel;
125 int ret_recv;
126
127 /* First send a status message before receiving the fds. */
128 ret = consumer_send_status_msg(sock, ret_code);
129 if (ret < 0) {
130 /* Somehow, the session daemon is not responding anymore. */
131 goto end_nosignal;
132 }
133 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
134 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
135 msg.u.channel.session_id, msg.u.channel.pathname,
136 msg.u.channel.name, msg.u.channel.uid, msg.u.channel.gid,
137 msg.u.channel.relayd_id, msg.u.channel.output,
138 msg.u.channel.tracefile_size,
139 msg.u.channel.tracefile_count);
140 if (new_channel == NULL) {
141 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
142 goto end_nosignal;
143 }
144 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
145
146 /* Translate and save channel type. */
147 switch (msg.u.channel.type) {
148 case CONSUMER_CHANNEL_TYPE_DATA:
149 case CONSUMER_CHANNEL_TYPE_METADATA:
150 new_channel->type = msg.u.channel.type;
151 break;
152 default:
153 assert(0);
154 goto end_nosignal;
155 };
156
157 if (ctx->on_recv_channel != NULL) {
158 ret_recv = ctx->on_recv_channel(new_channel);
159 if (ret_recv == 0) {
160 ret = consumer_add_channel(new_channel, ctx);
161 } else if (ret_recv < 0) {
162 goto end_nosignal;
163 }
164 } else {
165 ret = consumer_add_channel(new_channel, ctx);
166 }
167
168 /* If we received an error in add_channel, we need to report it. */
169 if (ret != 0) {
170 consumer_send_status_msg(sock, ret);
171 goto end_nosignal;
172 }
173
174 goto end_nosignal;
175 }
176 case LTTNG_CONSUMER_ADD_STREAM:
177 {
178 int fd;
179 struct lttng_pipe *stream_pipe;
180 struct consumer_relayd_sock_pair *relayd = NULL;
181 struct lttng_consumer_stream *new_stream;
182 struct lttng_consumer_channel *channel;
183 int alloc_ret = 0;
184
185 /*
186 * Get stream's channel reference. Needed when adding the stream to the
187 * global hash table.
188 */
189 channel = consumer_find_channel(msg.u.stream.channel_key);
190 if (!channel) {
191 /*
192 * We could not find the channel. Can happen if cpu hotplug
193 * happens while tearing down.
194 */
195 ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
196 ret_code = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
197 }
198
199 /* First send a status message before receiving the fds. */
200 ret = consumer_send_status_msg(sock, ret_code);
201 if (ret < 0 || ret_code != LTTNG_OK) {
202 /*
203 * Somehow, the session daemon is not responding anymore or the
204 * channel was not found.
205 */
206 goto end_nosignal;
207 }
208
209 /* block */
210 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
211 rcu_read_unlock();
212 return -EINTR;
213 }
214
215 /* Get stream file descriptor from socket */
216 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
217 if (ret != sizeof(fd)) {
218 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
219 rcu_read_unlock();
220 return ret;
221 }
222
223 /*
224 * Send status code to session daemon only if the recv works. If the
225 * above recv() failed, the session daemon is notified through the
226 * error socket and the teardown is eventually done.
227 */
228 ret = consumer_send_status_msg(sock, ret_code);
229 if (ret < 0) {
230 /* Somehow, the session daemon is not responding anymore. */
231 goto end_nosignal;
232 }
233
234 new_stream = consumer_allocate_stream(channel->key,
235 fd,
236 LTTNG_CONSUMER_ACTIVE_STREAM,
237 channel->name,
238 channel->uid,
239 channel->gid,
240 channel->relayd_id,
241 channel->session_id,
242 msg.u.stream.cpu,
243 &alloc_ret,
244 channel->type);
245 if (new_stream == NULL) {
246 switch (alloc_ret) {
247 case -ENOMEM:
248 case -EINVAL:
249 default:
250 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
251 break;
252 }
253 goto end_nosignal;
254 }
255 new_stream->chan = channel;
256 new_stream->wait_fd = fd;
257
258 /* Metadata chan refcount is increment in add_metadata_stream */
259 if (new_stream->chan->type != CONSUMER_CHANNEL_TYPE_METADATA) {
260 /* Update channel refcount */
261 uatomic_inc(&new_stream->chan->refcount);
262 }
263
264 /*
265 * The buffer flush is done on the session daemon side for the kernel
266 * so no need for the stream "hangup_flush_done" variable to be
267 * tracked. This is important for a kernel stream since we don't rely
268 * on the flush state of the stream to read data. It's not the case for
269 * user space tracing.
270 */
271 new_stream->hangup_flush_done = 0;
272
273 /* The stream is not metadata. Get relayd reference if exists. */
274 relayd = consumer_find_relayd(new_stream->net_seq_idx);
275 if (relayd != NULL) {
276 /* Add stream on the relayd */
277 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
278 ret = relayd_add_stream(&relayd->control_sock,
279 new_stream->name, new_stream->chan->pathname,
280 &new_stream->relayd_stream_id,
281 new_stream->chan->tracefile_size,
282 new_stream->chan->tracefile_count);
283 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
284 if (ret < 0) {
285 consumer_del_stream(new_stream, NULL);
286 goto end_nosignal;
287 }
288 } else if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
289 ERR("Network sequence index %" PRIu64 " unknown. Not adding stream.",
290 new_stream->net_seq_idx);
291 consumer_del_stream(new_stream, NULL);
292 goto end_nosignal;
293 }
294
295 if (ctx->on_recv_stream) {
296 ret = ctx->on_recv_stream(new_stream);
297 if (ret < 0) {
298 consumer_del_stream(new_stream, NULL);
299 goto end_nosignal;
300 }
301 }
302
303 /* Get the right pipe where the stream will be sent. */
304 if (new_stream->metadata_flag) {
305 stream_pipe = ctx->consumer_metadata_pipe;
306 } else {
307 stream_pipe = ctx->consumer_data_pipe;
308 }
309
310 ret = lttng_pipe_write(stream_pipe, &new_stream, sizeof(new_stream));
311 if (ret < 0) {
312 ERR("Consumer write %s stream to pipe %d",
313 new_stream->metadata_flag ? "metadata" : "data",
314 lttng_pipe_get_writefd(stream_pipe));
315 consumer_del_stream(new_stream, NULL);
316 goto end_nosignal;
317 }
318
319 DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64,
320 new_stream->name, fd, new_stream->relayd_stream_id);
321 break;
322 }
323 case LTTNG_CONSUMER_UPDATE_STREAM:
324 {
325 rcu_read_unlock();
326 return -ENOSYS;
327 }
328 case LTTNG_CONSUMER_DESTROY_RELAYD:
329 {
330 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
331 struct consumer_relayd_sock_pair *relayd;
332
333 DBG("Kernel consumer destroying relayd %" PRIu64, index);
334
335 /* Get relayd reference if exists. */
336 relayd = consumer_find_relayd(index);
337 if (relayd == NULL) {
338 DBG("Unable to find relayd %" PRIu64, index);
339 ret_code = LTTNG_ERR_NO_CONSUMER;
340 }
341
342 /*
343 * Each relayd socket pair has a refcount of stream attached to it
344 * which tells if the relayd is still active or not depending on the
345 * refcount value.
346 *
347 * This will set the destroy flag of the relayd object and destroy it
348 * if the refcount reaches zero when called.
349 *
350 * The destroy can happen either here or when a stream fd hangs up.
351 */
352 if (relayd) {
353 consumer_flag_relayd_for_destroy(relayd);
354 }
355
356 ret = consumer_send_status_msg(sock, ret_code);
357 if (ret < 0) {
358 /* Somehow, the session daemon is not responding anymore. */
359 goto end_nosignal;
360 }
361
362 goto end_nosignal;
363 }
364 case LTTNG_CONSUMER_DATA_PENDING:
365 {
366 int32_t ret;
367 uint64_t id = msg.u.data_pending.session_id;
368
369 DBG("Kernel consumer data pending command for id %" PRIu64, id);
370
371 ret = consumer_data_pending(id);
372
373 /* Send back returned value to session daemon */
374 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
375 if (ret < 0) {
376 PERROR("send data pending ret code");
377 }
378
379 /*
380 * No need to send back a status message since the data pending
381 * returned value is the response.
382 */
383 break;
384 }
385 default:
386 goto end_nosignal;
387 }
388
389 end_nosignal:
390 rcu_read_unlock();
391
392 /*
393 * Return 1 to indicate success since the 0 value can be a socket
394 * shutdown during the recv() or send() call.
395 */
396 return 1;
397 }
398
399 /*
400 * Consume data on a file descriptor and write it on a trace file.
401 */
402 ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
403 struct lttng_consumer_local_data *ctx)
404 {
405 unsigned long len, subbuf_size, padding;
406 int err;
407 ssize_t ret = 0;
408 int infd = stream->wait_fd;
409
410 DBG("In read_subbuffer (infd : %d)", infd);
411 /* Get the next subbuffer */
412 err = kernctl_get_next_subbuf(infd);
413 if (err != 0) {
414 ret = err;
415 /*
416 * This is a debug message even for single-threaded consumer,
417 * because poll() have more relaxed criterions than get subbuf,
418 * so get_subbuf may fail for short race windows where poll()
419 * would issue wakeups.
420 */
421 DBG("Reserving sub buffer failed (everything is normal, "
422 "it is due to concurrency)");
423 goto end;
424 }
425
426 /* Get the full subbuffer size including padding */
427 err = kernctl_get_padded_subbuf_size(infd, &len);
428 if (err != 0) {
429 errno = -err;
430 perror("Getting sub-buffer len failed.");
431 ret = err;
432 goto end;
433 }
434
435 switch (stream->chan->output) {
436 case LTTNG_EVENT_SPLICE:
437
438 /*
439 * XXX: The lttng-modules splice "actor" does not handle copying
440 * partial pages hence only using the subbuffer size without the
441 * padding makes the splice fail.
442 */
443 subbuf_size = len;
444 padding = 0;
445
446 /* splice the subbuffer to the tracefile */
447 ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, subbuf_size,
448 padding);
449 /*
450 * XXX: Splice does not support network streaming so the return value
451 * is simply checked against subbuf_size and not like the mmap() op.
452 */
453 if (ret != subbuf_size) {
454 /*
455 * display the error but continue processing to try
456 * to release the subbuffer
457 */
458 ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
459 ret, subbuf_size);
460 }
461 break;
462 case LTTNG_EVENT_MMAP:
463 /* Get subbuffer size without padding */
464 err = kernctl_get_subbuf_size(infd, &subbuf_size);
465 if (err != 0) {
466 errno = -err;
467 perror("Getting sub-buffer len failed.");
468 ret = err;
469 goto end;
470 }
471
472 /* Make sure the tracer is not gone mad on us! */
473 assert(len >= subbuf_size);
474
475 padding = len - subbuf_size;
476
477 /* write the subbuffer to the tracefile */
478 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
479 padding);
480 /*
481 * The mmap operation should write subbuf_size amount of data when
482 * network streaming or the full padding (len) size when we are _not_
483 * streaming.
484 */
485 if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
486 (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
487 /*
488 * Display the error but continue processing to try to release the
489 * subbuffer
490 */
491 ERR("Error writing to tracefile "
492 "(ret: %zd != len: %lu != subbuf_size: %lu)",
493 ret, len, subbuf_size);
494 }
495 break;
496 default:
497 ERR("Unknown output method");
498 ret = -1;
499 }
500
501 err = kernctl_put_next_subbuf(infd);
502 if (err != 0) {
503 errno = -err;
504 if (errno == EFAULT) {
505 perror("Error in unreserving sub buffer\n");
506 } else if (errno == EIO) {
507 /* Should never happen with newer LTTng versions */
508 perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
509 }
510
511 ret = -err;
512 goto end;
513 }
514
515 end:
516 return ret;
517 }
518
519 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
520 {
521 int ret;
522
523 assert(stream);
524
525 /* Don't create anything if this is set for streaming. */
526 if (stream->net_seq_idx == (uint64_t) -1ULL) {
527 ret = utils_create_stream_file(stream->chan->pathname, stream->name,
528 stream->chan->tracefile_size, stream->tracefile_count_current,
529 stream->uid, stream->gid);
530 if (ret < 0) {
531 goto error;
532 }
533 stream->out_fd = ret;
534 stream->tracefile_size_current = 0;
535 }
536
537 if (stream->output == LTTNG_EVENT_MMAP) {
538 /* get the len of the mmap region */
539 unsigned long mmap_len;
540
541 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
542 if (ret != 0) {
543 errno = -ret;
544 PERROR("kernctl_get_mmap_len");
545 goto error_close_fd;
546 }
547 stream->mmap_len = (size_t) mmap_len;
548
549 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
550 MAP_PRIVATE, stream->wait_fd, 0);
551 if (stream->mmap_base == MAP_FAILED) {
552 PERROR("Error mmaping");
553 ret = -1;
554 goto error_close_fd;
555 }
556 }
557
558 /* we return 0 to let the library handle the FD internally */
559 return 0;
560
561 error_close_fd:
562 {
563 int err;
564
565 err = close(stream->out_fd);
566 assert(!err);
567 }
568 error:
569 return ret;
570 }
571
572 /*
573 * Check if data is still being extracted from the buffers for a specific
574 * stream. Consumer data lock MUST be acquired before calling this function
575 * and the stream lock.
576 *
577 * Return 1 if the traced data are still getting read else 0 meaning that the
578 * data is available for trace viewer reading.
579 */
580 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
581 {
582 int ret;
583
584 assert(stream);
585
586 ret = kernctl_get_next_subbuf(stream->wait_fd);
587 if (ret == 0) {
588 /* There is still data so let's put back this subbuffer. */
589 ret = kernctl_put_subbuf(stream->wait_fd);
590 assert(ret == 0);
591 ret = 1; /* Data is pending */
592 goto end;
593 }
594
595 /* Data is NOT pending and ready to be read. */
596 ret = 0;
597
598 end:
599 return ret;
600 }
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