Fix: goto error_fatal on lttng_kconsumer_recv_cmd errors
[lttng-tools.git] / src / common / kernel-consumer / kernel-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>
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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>
77c7c900 28#include <inttypes.h>
3bd1e081 29#include <unistd.h>
dbb5dfe6 30#include <sys/stat.h>
3bd1e081 31
990570ed 32#include <common/common.h>
10a8a223 33#include <common/kernel-ctl/kernel-ctl.h>
10a8a223 34#include <common/sessiond-comm/sessiond-comm.h>
00e2e675 35#include <common/sessiond-comm/relayd.h>
dbb5dfe6 36#include <common/compat/fcntl.h>
acdb9057 37#include <common/pipe.h>
00e2e675 38#include <common/relayd/relayd.h>
fe4477ee 39#include <common/utils.h>
0857097f 40
10a8a223 41#include "kernel-consumer.h"
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42
43extern struct lttng_consumer_global_data consumer_data;
44extern int consumer_poll_timeout;
45extern volatile int consumer_quit;
46
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47/*
48 * Take a snapshot for a specific fd
49 *
50 * Returns 0 on success, < 0 on error
51 */
ffe60014 52int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream *stream)
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MD
53{
54 int ret = 0;
55 int infd = stream->wait_fd;
56
57 ret = kernctl_snapshot(infd);
58 if (ret != 0) {
87dc6a9c 59 errno = -ret;
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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 */
ffe60014 71int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
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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) {
87dc6a9c 79 errno = -ret;
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80 perror("kernctl_snapshot_get_produced");
81 }
82
83 return ret;
84}
85
1803a064
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86/*
87 * Receive command from session daemon and process it.
88 *
89 * Return 1 on success else a negative value or 0.
90 */
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91int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
92 int sock, struct pollfd *consumer_sockpoll)
93{
94 ssize_t ret;
f50f23d9 95 enum lttng_error_code ret_code = LTTNG_OK;
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96 struct lttcomm_consumer_msg msg;
97
98 ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
99 if (ret != sizeof(msg)) {
f73fabfd 100 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
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101 if (ret > 0) {
102 ret = -1;
103 }
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104 return ret;
105 }
106 if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
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107 /*
108 * Notify the session daemon that the command is completed.
109 *
110 * On transport layer error, the function call will print an error
111 * message so handling the returned code is a bit useless since we
112 * return an error code anyway.
113 */
114 (void) consumer_send_status_msg(sock, ret_code);
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115 return -ENOENT;
116 }
117
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118 /* relayd needs RCU read-side protection */
119 rcu_read_lock();
120
3bd1e081 121 switch (msg.cmd_type) {
00e2e675
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122 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
123 {
f50f23d9 124 /* Session daemon status message are handled in the following call. */
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125 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
126 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
46e6455f 127 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id);
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128 goto end_nosignal;
129 }
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130 case LTTNG_CONSUMER_ADD_CHANNEL:
131 {
132 struct lttng_consumer_channel *new_channel;
e43c41c5 133 int ret_recv;
3bd1e081 134
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135 /* First send a status message before receiving the fds. */
136 ret = consumer_send_status_msg(sock, ret_code);
137 if (ret < 0) {
138 /* Somehow, the session daemon is not responding anymore. */
1803a064 139 goto error_fatal;
f50f23d9 140 }
d88aee68 141 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
3bd1e081 142 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
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143 msg.u.channel.session_id, msg.u.channel.pathname,
144 msg.u.channel.name, msg.u.channel.uid, msg.u.channel.gid,
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145 msg.u.channel.relayd_id, msg.u.channel.output,
146 msg.u.channel.tracefile_size,
147 msg.u.channel.tracefile_count);
3bd1e081 148 if (new_channel == NULL) {
f73fabfd 149 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
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150 goto end_nosignal;
151 }
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152 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
153
154 /* Translate and save channel type. */
155 switch (msg.u.channel.type) {
156 case CONSUMER_CHANNEL_TYPE_DATA:
157 case CONSUMER_CHANNEL_TYPE_METADATA:
158 new_channel->type = msg.u.channel.type;
159 break;
160 default:
161 assert(0);
162 goto end_nosignal;
163 };
164
3bd1e081 165 if (ctx->on_recv_channel != NULL) {
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166 ret_recv = ctx->on_recv_channel(new_channel);
167 if (ret_recv == 0) {
168 ret = consumer_add_channel(new_channel, ctx);
169 } else if (ret_recv < 0) {
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170 goto end_nosignal;
171 }
172 } else {
e43c41c5 173 ret = consumer_add_channel(new_channel, ctx);
3bd1e081 174 }
e43c41c5
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175
176 /* If we received an error in add_channel, we need to report it. */
177 if (ret != 0) {
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178 ret = consumer_send_status_msg(sock, ret);
179 if (ret < 0) {
180 goto error_fatal;
181 }
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182 goto end_nosignal;
183 }
184
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185 goto end_nosignal;
186 }
187 case LTTNG_CONSUMER_ADD_STREAM:
188 {
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189 int fd;
190 struct lttng_pipe *stream_pipe;
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191 struct consumer_relayd_sock_pair *relayd = NULL;
192 struct lttng_consumer_stream *new_stream;
ffe60014 193 struct lttng_consumer_channel *channel;
c80048c6 194 int alloc_ret = 0;
3bd1e081 195
ffe60014
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196 /*
197 * Get stream's channel reference. Needed when adding the stream to the
198 * global hash table.
199 */
200 channel = consumer_find_channel(msg.u.stream.channel_key);
201 if (!channel) {
202 /*
203 * We could not find the channel. Can happen if cpu hotplug
204 * happens while tearing down.
205 */
d88aee68 206 ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
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207 ret_code = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
208 }
209
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210 /* First send a status message before receiving the fds. */
211 ret = consumer_send_status_msg(sock, ret_code);
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212 if (ret < 0) {
213 /*
214 * Somehow, the session daemon is not responding
215 * anymore.
216 */
217 goto error_fatal;
218 }
219 if (ret_code != LTTNG_OK) {
ffe60014 220 /*
1803a064 221 * Channel was not found.
ffe60014 222 */
f50f23d9
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223 goto end_nosignal;
224 }
225
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226 /* block */
227 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
3f8e211f 228 rcu_read_unlock();
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229 return -EINTR;
230 }
00e2e675
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231
232 /* Get stream file descriptor from socket */
f2fc6720
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233 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
234 if (ret != sizeof(fd)) {
f73fabfd 235 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
3f8e211f 236 rcu_read_unlock();
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237 return ret;
238 }
3bd1e081 239
f50f23d9
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240 /*
241 * Send status code to session daemon only if the recv works. If the
242 * above recv() failed, the session daemon is notified through the
243 * error socket and the teardown is eventually done.
244 */
245 ret = consumer_send_status_msg(sock, ret_code);
246 if (ret < 0) {
247 /* Somehow, the session daemon is not responding anymore. */
248 goto end_nosignal;
249 }
250
ffe60014
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251 new_stream = consumer_allocate_stream(channel->key,
252 fd,
253 LTTNG_CONSUMER_ACTIVE_STREAM,
254 channel->name,
255 channel->uid,
256 channel->gid,
257 channel->relayd_id,
258 channel->session_id,
259 msg.u.stream.cpu,
260 &alloc_ret,
261 channel->type);
3bd1e081 262 if (new_stream == NULL) {
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MD
263 switch (alloc_ret) {
264 case -ENOMEM:
265 case -EINVAL:
266 default:
267 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
268 break;
c80048c6 269 }
3f8e211f 270 goto end_nosignal;
3bd1e081 271 }
ffe60014
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272 new_stream->chan = channel;
273 new_stream->wait_fd = fd;
00e2e675 274
a0c83db9
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275 /*
276 * We've just assigned the channel to the stream so increment the
277 * refcount right now.
278 */
279 uatomic_inc(&new_stream->chan->refcount);
9d9353f9 280
fb3a43a9
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281 /*
282 * The buffer flush is done on the session daemon side for the kernel
283 * so no need for the stream "hangup_flush_done" variable to be
284 * tracked. This is important for a kernel stream since we don't rely
285 * on the flush state of the stream to read data. It's not the case for
286 * user space tracing.
287 */
288 new_stream->hangup_flush_done = 0;
289
00e2e675 290 /* The stream is not metadata. Get relayd reference if exists. */
ffe60014 291 relayd = consumer_find_relayd(new_stream->net_seq_idx);
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DG
292 if (relayd != NULL) {
293 /* Add stream on the relayd */
294 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
295 ret = relayd_add_stream(&relayd->control_sock,
ffe60014 296 new_stream->name, new_stream->chan->pathname,
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297 &new_stream->relayd_stream_id,
298 new_stream->chan->tracefile_size,
299 new_stream->chan->tracefile_count);
00e2e675
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300 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
301 if (ret < 0) {
e316aad5 302 consumer_del_stream(new_stream, NULL);
3f8e211f 303 goto end_nosignal;
00e2e675 304 }
d88aee68
DG
305 } else if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
306 ERR("Network sequence index %" PRIu64 " unknown. Not adding stream.",
ffe60014 307 new_stream->net_seq_idx);
e316aad5 308 consumer_del_stream(new_stream, NULL);
3f8e211f 309 goto end_nosignal;
00e2e675
DG
310 }
311
633d0084
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312 if (ctx->on_recv_stream) {
313 ret = ctx->on_recv_stream(new_stream);
314 if (ret < 0) {
e316aad5 315 consumer_del_stream(new_stream, NULL);
633d0084 316 goto end_nosignal;
fb3a43a9 317 }
633d0084 318 }
fb3a43a9 319
50f8ae69 320 /* Get the right pipe where the stream will be sent. */
633d0084 321 if (new_stream->metadata_flag) {
dae10966 322 stream_pipe = ctx->consumer_metadata_pipe;
3bd1e081 323 } else {
dae10966 324 stream_pipe = ctx->consumer_data_pipe;
50f8ae69
DG
325 }
326
dae10966 327 ret = lttng_pipe_write(stream_pipe, &new_stream, sizeof(new_stream));
50f8ae69 328 if (ret < 0) {
dae10966 329 ERR("Consumer write %s stream to pipe %d",
50f8ae69 330 new_stream->metadata_flag ? "metadata" : "data",
dae10966 331 lttng_pipe_get_writefd(stream_pipe));
50f8ae69
DG
332 consumer_del_stream(new_stream, NULL);
333 goto end_nosignal;
3bd1e081 334 }
00e2e675 335
50f8ae69 336 DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64,
ffe60014 337 new_stream->name, fd, new_stream->relayd_stream_id);
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MD
338 break;
339 }
340 case LTTNG_CONSUMER_UPDATE_STREAM:
341 {
3f8e211f
DG
342 rcu_read_unlock();
343 return -ENOSYS;
344 }
345 case LTTNG_CONSUMER_DESTROY_RELAYD:
346 {
a6ba4fe1 347 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
3f8e211f
DG
348 struct consumer_relayd_sock_pair *relayd;
349
a6ba4fe1 350 DBG("Kernel consumer destroying relayd %" PRIu64, index);
3f8e211f
DG
351
352 /* Get relayd reference if exists. */
a6ba4fe1 353 relayd = consumer_find_relayd(index);
3f8e211f 354 if (relayd == NULL) {
3448e266 355 DBG("Unable to find relayd %" PRIu64, index);
f50f23d9 356 ret_code = LTTNG_ERR_NO_CONSUMER;
3bd1e081 357 }
3f8e211f 358
a6ba4fe1
DG
359 /*
360 * Each relayd socket pair has a refcount of stream attached to it
361 * which tells if the relayd is still active or not depending on the
362 * refcount value.
363 *
364 * This will set the destroy flag of the relayd object and destroy it
365 * if the refcount reaches zero when called.
366 *
367 * The destroy can happen either here or when a stream fd hangs up.
368 */
f50f23d9
DG
369 if (relayd) {
370 consumer_flag_relayd_for_destroy(relayd);
371 }
372
373 ret = consumer_send_status_msg(sock, ret_code);
374 if (ret < 0) {
375 /* Somehow, the session daemon is not responding anymore. */
1803a064 376 goto error_fatal;
f50f23d9 377 }
3f8e211f 378
3f8e211f 379 goto end_nosignal;
3bd1e081 380 }
6d805429 381 case LTTNG_CONSUMER_DATA_PENDING:
53632229 382 {
c8f59ee5 383 int32_t ret;
6d805429 384 uint64_t id = msg.u.data_pending.session_id;
c8f59ee5 385
6d805429 386 DBG("Kernel consumer data pending command for id %" PRIu64, id);
c8f59ee5 387
6d805429 388 ret = consumer_data_pending(id);
c8f59ee5
DG
389
390 /* Send back returned value to session daemon */
391 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
392 if (ret < 0) {
6d805429 393 PERROR("send data pending ret code");
1803a064 394 goto error_fatal;
c8f59ee5 395 }
f50f23d9
DG
396
397 /*
398 * No need to send back a status message since the data pending
399 * returned value is the response.
400 */
c8f59ee5 401 break;
53632229 402 }
3bd1e081 403 default:
3f8e211f 404 goto end_nosignal;
3bd1e081 405 }
3f8e211f 406
3bd1e081 407end_nosignal:
b0b335c8 408 rcu_read_unlock();
4cbc1a04
DG
409
410 /*
411 * Return 1 to indicate success since the 0 value can be a socket
412 * shutdown during the recv() or send() call.
413 */
414 return 1;
1803a064
MD
415
416error_fatal:
417 rcu_read_unlock();
418 /* This will issue a consumer stop. */
419 return -1;
3bd1e081 420}
d41f73b7
MD
421
422/*
423 * Consume data on a file descriptor and write it on a trace file.
424 */
4078b776 425ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
d41f73b7
MD
426 struct lttng_consumer_local_data *ctx)
427{
1d4dfdef 428 unsigned long len, subbuf_size, padding;
d41f73b7 429 int err;
4078b776 430 ssize_t ret = 0;
d41f73b7
MD
431 int infd = stream->wait_fd;
432
433 DBG("In read_subbuffer (infd : %d)", infd);
434 /* Get the next subbuffer */
435 err = kernctl_get_next_subbuf(infd);
436 if (err != 0) {
1d4dfdef 437 ret = err;
d41f73b7
MD
438 /*
439 * This is a debug message even for single-threaded consumer,
440 * because poll() have more relaxed criterions than get subbuf,
441 * so get_subbuf may fail for short race windows where poll()
442 * would issue wakeups.
443 */
444 DBG("Reserving sub buffer failed (everything is normal, "
445 "it is due to concurrency)");
446 goto end;
447 }
448
1d4dfdef
DG
449 /* Get the full subbuffer size including padding */
450 err = kernctl_get_padded_subbuf_size(infd, &len);
451 if (err != 0) {
452 errno = -err;
453 perror("Getting sub-buffer len failed.");
454 ret = err;
455 goto end;
456 }
457
ffe60014 458 switch (stream->chan->output) {
1d4dfdef 459 case LTTNG_EVENT_SPLICE:
d41f73b7 460
1d4dfdef
DG
461 /*
462 * XXX: The lttng-modules splice "actor" does not handle copying
463 * partial pages hence only using the subbuffer size without the
464 * padding makes the splice fail.
465 */
466 subbuf_size = len;
467 padding = 0;
468
469 /* splice the subbuffer to the tracefile */
91dfef6e
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470 ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, subbuf_size,
471 padding);
472 /*
473 * XXX: Splice does not support network streaming so the return value
474 * is simply checked against subbuf_size and not like the mmap() op.
475 */
1d4dfdef
DG
476 if (ret != subbuf_size) {
477 /*
478 * display the error but continue processing to try
479 * to release the subbuffer
480 */
481 ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
482 ret, subbuf_size);
483 }
484 break;
485 case LTTNG_EVENT_MMAP:
486 /* Get subbuffer size without padding */
487 err = kernctl_get_subbuf_size(infd, &subbuf_size);
488 if (err != 0) {
489 errno = -err;
490 perror("Getting sub-buffer len failed.");
491 ret = err;
492 goto end;
493 }
47e81c02 494
1d4dfdef
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495 /* Make sure the tracer is not gone mad on us! */
496 assert(len >= subbuf_size);
497
498 padding = len - subbuf_size;
499
500 /* write the subbuffer to the tracefile */
91dfef6e
DG
501 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
502 padding);
503 /*
504 * The mmap operation should write subbuf_size amount of data when
505 * network streaming or the full padding (len) size when we are _not_
506 * streaming.
507 */
d88aee68
DG
508 if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
509 (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
1d4dfdef 510 /*
91dfef6e
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511 * Display the error but continue processing to try to release the
512 * subbuffer
1d4dfdef 513 */
91dfef6e
DG
514 ERR("Error writing to tracefile "
515 "(ret: %zd != len: %lu != subbuf_size: %lu)",
516 ret, len, subbuf_size);
1d4dfdef
DG
517 }
518 break;
519 default:
520 ERR("Unknown output method");
521 ret = -1;
d41f73b7
MD
522 }
523
524 err = kernctl_put_next_subbuf(infd);
525 if (err != 0) {
21073eaa 526 errno = -err;
d41f73b7
MD
527 if (errno == EFAULT) {
528 perror("Error in unreserving sub buffer\n");
529 } else if (errno == EIO) {
530 /* Should never happen with newer LTTng versions */
531 perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
532 }
21073eaa
DG
533
534 ret = -err;
d41f73b7
MD
535 goto end;
536 }
537
538end:
539 return ret;
540}
541
542int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
543{
544 int ret;
ffe60014
DG
545
546 assert(stream);
547
fe4477ee
JD
548 /* Don't create anything if this is set for streaming. */
549 if (stream->net_seq_idx == (uint64_t) -1ULL) {
550 ret = utils_create_stream_file(stream->chan->pathname, stream->name,
551 stream->chan->tracefile_size, stream->tracefile_count_current,
552 stream->uid, stream->gid);
553 if (ret < 0) {
554 goto error;
555 }
556 stream->out_fd = ret;
557 stream->tracefile_size_current = 0;
ffe60014 558 }
d41f73b7 559
d41f73b7
MD
560 if (stream->output == LTTNG_EVENT_MMAP) {
561 /* get the len of the mmap region */
562 unsigned long mmap_len;
563
564 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
565 if (ret != 0) {
87dc6a9c 566 errno = -ret;
ffe60014 567 PERROR("kernctl_get_mmap_len");
d41f73b7
MD
568 goto error_close_fd;
569 }
570 stream->mmap_len = (size_t) mmap_len;
571
ffe60014
DG
572 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
573 MAP_PRIVATE, stream->wait_fd, 0);
d41f73b7 574 if (stream->mmap_base == MAP_FAILED) {
ffe60014 575 PERROR("Error mmaping");
d41f73b7
MD
576 ret = -1;
577 goto error_close_fd;
578 }
579 }
580
581 /* we return 0 to let the library handle the FD internally */
582 return 0;
583
584error_close_fd:
585 {
586 int err;
587
588 err = close(stream->out_fd);
589 assert(!err);
590 }
591error:
592 return ret;
593}
594
ca22feea
DG
595/*
596 * Check if data is still being extracted from the buffers for a specific
4e9a4686
DG
597 * stream. Consumer data lock MUST be acquired before calling this function
598 * and the stream lock.
ca22feea 599 *
6d805429 600 * Return 1 if the traced data are still getting read else 0 meaning that the
ca22feea
DG
601 * data is available for trace viewer reading.
602 */
6d805429 603int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
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604{
605 int ret;
606
607 assert(stream);
608
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609 ret = kernctl_get_next_subbuf(stream->wait_fd);
610 if (ret == 0) {
611 /* There is still data so let's put back this subbuffer. */
612 ret = kernctl_put_subbuf(stream->wait_fd);
613 assert(ret == 0);
6d805429 614 ret = 1; /* Data is pending */
4e9a4686 615 goto end;
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616 }
617
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618 /* Data is NOT pending and ready to be read. */
619 ret = 0;
ca22feea 620
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621end:
622 return ret;
ca22feea 623}
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