Fix: Stream allocation and insertion consistency
[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>
00e2e675 37#include <common/relayd/relayd.h>
0857097f 38
10a8a223 39#include "kernel-consumer.h"
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40
41extern struct lttng_consumer_global_data consumer_data;
42extern int consumer_poll_timeout;
43extern volatile int consumer_quit;
44
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45/*
46 * Take a snapshot for a specific fd
47 *
48 * Returns 0 on success, < 0 on error
49 */
50int lttng_kconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
51 struct lttng_consumer_stream *stream)
52{
53 int ret = 0;
54 int infd = stream->wait_fd;
55
56 ret = kernctl_snapshot(infd);
57 if (ret != 0) {
87dc6a9c 58 errno = -ret;
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59 perror("Getting sub-buffer snapshot.");
60 }
61
62 return ret;
63}
64
65/*
66 * Get the produced position
67 *
68 * Returns 0 on success, < 0 on error
69 */
70int lttng_kconsumer_get_produced_snapshot(
71 struct lttng_consumer_local_data *ctx,
72 struct lttng_consumer_stream *stream,
73 unsigned long *pos)
74{
75 int ret;
76 int infd = stream->wait_fd;
77
78 ret = kernctl_snapshot_get_produced(infd, pos);
79 if (ret != 0) {
87dc6a9c 80 errno = -ret;
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81 perror("kernctl_snapshot_get_produced");
82 }
83
84 return ret;
85}
86
87int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
88 int sock, struct pollfd *consumer_sockpoll)
89{
90 ssize_t ret;
91 struct lttcomm_consumer_msg msg;
92
93 ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
94 if (ret != sizeof(msg)) {
f73fabfd 95 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
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96 return ret;
97 }
98 if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
99 return -ENOENT;
100 }
101
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102 /* relayd needs RCU read-side protection */
103 rcu_read_lock();
104
3bd1e081 105 switch (msg.cmd_type) {
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106 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
107 {
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108 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
109 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
110 &msg.u.relayd_sock.sock);
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111 goto end_nosignal;
112 }
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113 case LTTNG_CONSUMER_ADD_CHANNEL:
114 {
115 struct lttng_consumer_channel *new_channel;
116
117 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
118 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
119 -1, -1,
120 msg.u.channel.mmap_len,
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121 msg.u.channel.max_sb_size,
122 msg.u.channel.nb_init_streams);
3bd1e081 123 if (new_channel == NULL) {
f73fabfd 124 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
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125 goto end_nosignal;
126 }
127 if (ctx->on_recv_channel != NULL) {
128 ret = ctx->on_recv_channel(new_channel);
129 if (ret == 0) {
130 consumer_add_channel(new_channel);
131 } else if (ret < 0) {
132 goto end_nosignal;
133 }
134 } else {
135 consumer_add_channel(new_channel);
136 }
137 goto end_nosignal;
138 }
139 case LTTNG_CONSUMER_ADD_STREAM:
140 {
f2fc6720 141 int fd;
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142 struct consumer_relayd_sock_pair *relayd = NULL;
143 struct lttng_consumer_stream *new_stream;
c80048c6 144 int alloc_ret = 0;
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145
146 /* block */
147 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
3f8e211f 148 rcu_read_unlock();
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149 return -EINTR;
150 }
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151
152 /* Get stream file descriptor from socket */
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153 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
154 if (ret != sizeof(fd)) {
f73fabfd 155 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
3f8e211f 156 rcu_read_unlock();
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157 return ret;
158 }
3bd1e081 159
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160 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
161 msg.u.stream.stream_key,
f2fc6720 162 fd, fd,
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163 msg.u.stream.state,
164 msg.u.stream.mmap_len,
165 msg.u.stream.output,
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166 msg.u.stream.path_name,
167 msg.u.stream.uid,
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168 msg.u.stream.gid,
169 msg.u.stream.net_index,
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170 msg.u.stream.metadata_flag,
171 &alloc_ret);
3bd1e081 172 if (new_stream == NULL) {
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173 switch (alloc_ret) {
174 case -ENOMEM:
175 case -EINVAL:
176 default:
177 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
178 break;
179 case -ENOENT:
180 /*
181 * We could not find the channel. Can happen if cpu hotplug
182 * happens while tearing down.
183 */
184 DBG3("Could not find channel");
185 break;
186 }
3f8e211f 187 goto end_nosignal;
3bd1e081 188 }
00e2e675 189
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190 /*
191 * The buffer flush is done on the session daemon side for the kernel
192 * so no need for the stream "hangup_flush_done" variable to be
193 * tracked. This is important for a kernel stream since we don't rely
194 * on the flush state of the stream to read data. It's not the case for
195 * user space tracing.
196 */
197 new_stream->hangup_flush_done = 0;
198
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199 /* The stream is not metadata. Get relayd reference if exists. */
200 relayd = consumer_find_relayd(msg.u.stream.net_index);
201 if (relayd != NULL) {
202 /* Add stream on the relayd */
203 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
204 ret = relayd_add_stream(&relayd->control_sock,
205 msg.u.stream.name, msg.u.stream.path_name,
206 &new_stream->relayd_stream_id);
207 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
208 if (ret < 0) {
e316aad5 209 consumer_del_stream(new_stream, NULL);
3f8e211f 210 goto end_nosignal;
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211 }
212 } else if (msg.u.stream.net_index != -1) {
213 ERR("Network sequence index %d unknown. Not adding stream.",
214 msg.u.stream.net_index);
e316aad5 215 consumer_del_stream(new_stream, NULL);
3f8e211f 216 goto end_nosignal;
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217 }
218
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219 if (ctx->on_recv_stream) {
220 ret = ctx->on_recv_stream(new_stream);
221 if (ret < 0) {
e316aad5 222 consumer_del_stream(new_stream, NULL);
633d0084 223 goto end_nosignal;
fb3a43a9 224 }
633d0084 225 }
fb3a43a9 226
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227 /* Send stream to the metadata thread */
228 if (new_stream->metadata_flag) {
fb3a43a9 229 do {
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230 ret = write(ctx->consumer_metadata_pipe[1], &new_stream,
231 sizeof(new_stream));
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232 } while (ret < 0 && errno == EINTR);
233 if (ret < 0) {
234 PERROR("write metadata pipe");
e316aad5 235 consumer_del_stream(new_stream, NULL);
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236 }
237 } else {
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238 ret = consumer_add_stream(new_stream);
239 if (ret) {
240 ERR("Consumer add stream %d failed. Continuing",
241 new_stream->key);
242 consumer_del_stream(new_stream, NULL);
243 goto end_nosignal;
244 }
3bd1e081 245 }
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246
247 DBG("Kernel consumer_add_stream (%d)", fd);
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248 break;
249 }
250 case LTTNG_CONSUMER_UPDATE_STREAM:
251 {
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252 rcu_read_unlock();
253 return -ENOSYS;
254 }
255 case LTTNG_CONSUMER_DESTROY_RELAYD:
256 {
a6ba4fe1 257 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
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258 struct consumer_relayd_sock_pair *relayd;
259
a6ba4fe1 260 DBG("Kernel consumer destroying relayd %" PRIu64, index);
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261
262 /* Get relayd reference if exists. */
a6ba4fe1 263 relayd = consumer_find_relayd(index);
3f8e211f 264 if (relayd == NULL) {
a6ba4fe1 265 ERR("Unable to find relayd %" PRIu64, index);
3f8e211f 266 goto end_nosignal;
3bd1e081 267 }
3f8e211f 268
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269 /*
270 * Each relayd socket pair has a refcount of stream attached to it
271 * which tells if the relayd is still active or not depending on the
272 * refcount value.
273 *
274 * This will set the destroy flag of the relayd object and destroy it
275 * if the refcount reaches zero when called.
276 *
277 * The destroy can happen either here or when a stream fd hangs up.
278 */
279 consumer_flag_relayd_for_destroy(relayd);
3f8e211f 280
3f8e211f 281 goto end_nosignal;
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282 }
283 default:
3f8e211f 284 goto end_nosignal;
3bd1e081 285 }
3f8e211f 286
04fdd819 287 /*
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288 * Wake-up the other end by writing a null byte in the pipe (non-blocking).
289 * Important note: Because writing into the pipe is non-blocking (and
290 * therefore we allow dropping wakeup data, as long as there is wakeup data
291 * present in the pipe buffer to wake up the other end), the other end
292 * should perform the following sequence for waiting:
293 *
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294 * 1) empty the pipe (reads).
295 * 2) perform update operation.
296 * 3) wait on the pipe (poll).
297 */
298 do {
299 ret = write(ctx->consumer_poll_pipe[1], "", 1);
6f94560a 300 } while (ret < 0 && errno == EINTR);
3bd1e081 301end_nosignal:
b0b335c8 302 rcu_read_unlock();
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303
304 /*
305 * Return 1 to indicate success since the 0 value can be a socket
306 * shutdown during the recv() or send() call.
307 */
308 return 1;
3bd1e081 309}
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310
311/*
312 * Consume data on a file descriptor and write it on a trace file.
313 */
4078b776 314ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
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315 struct lttng_consumer_local_data *ctx)
316{
1d4dfdef 317 unsigned long len, subbuf_size, padding;
d41f73b7 318 int err;
4078b776 319 ssize_t ret = 0;
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320 int infd = stream->wait_fd;
321
322 DBG("In read_subbuffer (infd : %d)", infd);
323 /* Get the next subbuffer */
324 err = kernctl_get_next_subbuf(infd);
325 if (err != 0) {
1d4dfdef 326 ret = err;
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327 /*
328 * This is a debug message even for single-threaded consumer,
329 * because poll() have more relaxed criterions than get subbuf,
330 * so get_subbuf may fail for short race windows where poll()
331 * would issue wakeups.
332 */
333 DBG("Reserving sub buffer failed (everything is normal, "
334 "it is due to concurrency)");
335 goto end;
336 }
337
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338 /* Get the full subbuffer size including padding */
339 err = kernctl_get_padded_subbuf_size(infd, &len);
340 if (err != 0) {
341 errno = -err;
342 perror("Getting sub-buffer len failed.");
343 ret = err;
344 goto end;
345 }
346
d41f73b7 347 switch (stream->output) {
1d4dfdef 348 case LTTNG_EVENT_SPLICE:
d41f73b7 349
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350 /*
351 * XXX: The lttng-modules splice "actor" does not handle copying
352 * partial pages hence only using the subbuffer size without the
353 * padding makes the splice fail.
354 */
355 subbuf_size = len;
356 padding = 0;
357
358 /* splice the subbuffer to the tracefile */
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359 ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, subbuf_size,
360 padding);
361 /*
362 * XXX: Splice does not support network streaming so the return value
363 * is simply checked against subbuf_size and not like the mmap() op.
364 */
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365 if (ret != subbuf_size) {
366 /*
367 * display the error but continue processing to try
368 * to release the subbuffer
369 */
370 ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
371 ret, subbuf_size);
372 }
373 break;
374 case LTTNG_EVENT_MMAP:
375 /* Get subbuffer size without padding */
376 err = kernctl_get_subbuf_size(infd, &subbuf_size);
377 if (err != 0) {
378 errno = -err;
379 perror("Getting sub-buffer len failed.");
380 ret = err;
381 goto end;
382 }
47e81c02 383
1d4dfdef
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384 /* Make sure the tracer is not gone mad on us! */
385 assert(len >= subbuf_size);
386
387 padding = len - subbuf_size;
388
389 /* write the subbuffer to the tracefile */
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390 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
391 padding);
392 /*
393 * The mmap operation should write subbuf_size amount of data when
394 * network streaming or the full padding (len) size when we are _not_
395 * streaming.
396 */
397 if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
398 (ret != len && stream->net_seq_idx == -1)) {
1d4dfdef 399 /*
91dfef6e
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400 * Display the error but continue processing to try to release the
401 * subbuffer
1d4dfdef 402 */
91dfef6e
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403 ERR("Error writing to tracefile "
404 "(ret: %zd != len: %lu != subbuf_size: %lu)",
405 ret, len, subbuf_size);
1d4dfdef
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406 }
407 break;
408 default:
409 ERR("Unknown output method");
410 ret = -1;
d41f73b7
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411 }
412
413 err = kernctl_put_next_subbuf(infd);
414 if (err != 0) {
21073eaa 415 errno = -err;
d41f73b7
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416 if (errno == EFAULT) {
417 perror("Error in unreserving sub buffer\n");
418 } else if (errno == EIO) {
419 /* Should never happen with newer LTTng versions */
420 perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
421 }
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422
423 ret = -err;
d41f73b7
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424 goto end;
425 }
426
427end:
428 return ret;
429}
430
431int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
432{
433 int ret;
434
435 /* Opening the tracefile in write mode */
00e2e675 436 if (strlen(stream->path_name) > 0 && stream->net_seq_idx == -1) {
e11d277b 437 ret = run_as_open(stream->path_name,
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438 O_WRONLY|O_CREAT|O_TRUNC,
439 S_IRWXU|S_IRWXG|S_IRWXO,
440 stream->uid, stream->gid);
d41f73b7
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441 if (ret < 0) {
442 ERR("Opening %s", stream->path_name);
443 perror("open");
444 goto error;
445 }
446 stream->out_fd = ret;
447 }
448
449 if (stream->output == LTTNG_EVENT_MMAP) {
450 /* get the len of the mmap region */
451 unsigned long mmap_len;
452
453 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
454 if (ret != 0) {
87dc6a9c 455 errno = -ret;
d41f73b7
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456 perror("kernctl_get_mmap_len");
457 goto error_close_fd;
458 }
459 stream->mmap_len = (size_t) mmap_len;
460
461 stream->mmap_base = mmap(NULL, stream->mmap_len,
462 PROT_READ, MAP_PRIVATE, stream->wait_fd, 0);
463 if (stream->mmap_base == MAP_FAILED) {
464 perror("Error mmaping");
465 ret = -1;
466 goto error_close_fd;
467 }
468 }
469
470 /* we return 0 to let the library handle the FD internally */
471 return 0;
472
473error_close_fd:
474 {
475 int err;
476
477 err = close(stream->out_fd);
478 assert(!err);
479 }
480error:
481 return ret;
482}
483
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