Fix: Consumer return value check after mmap/splice
[lttng-tools.git] / src / common / ust-consumer / ust-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 <lttng/ust-ctl.h>
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>
28 #include <sys/stat.h>
29 #include <sys/types.h>
30 #include <inttypes.h>
31 #include <unistd.h>
32
33 #include <common/common.h>
34 #include <common/sessiond-comm/sessiond-comm.h>
35 #include <common/relayd/relayd.h>
36 #include <common/compat/fcntl.h>
37
38 #include "ust-consumer.h"
39
40 extern struct lttng_consumer_global_data consumer_data;
41 extern int consumer_poll_timeout;
42 extern volatile int consumer_quit;
43
44 /*
45 * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
46 * compiled out, we isolate it in this library.
47 */
48 int lttng_ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
49 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
50 {
51 return ustctl_get_mmap_read_offset(handle, buf, off);
52 };
53
54 /*
55 * Take a snapshot for a specific fd
56 *
57 * Returns 0 on success, < 0 on error
58 */
59 int 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) {
66 errno = -ret;
67 PERROR("Getting sub-buffer snapshot.");
68 }
69
70 return ret;
71 }
72
73 /*
74 * Get the produced position
75 *
76 * Returns 0 on success, < 0 on error
77 */
78 int 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) {
88 errno = -ret;
89 PERROR("kernctl_snapshot_get_produced");
90 }
91
92 return ret;
93 }
94
95 /*
96 * Receive command from session daemon and process it.
97 *
98 * Return 1 on success else a negative value or 0.
99 */
100 int 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)) {
108 DBG("Consumer received unexpected message size %zd (expects %zu)",
109 ret, sizeof(msg));
110 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
111 return ret;
112 }
113 if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
114 return -ENOENT;
115 }
116
117 /* relayd needs RCU read-side lock */
118 rcu_read_lock();
119
120 switch (msg.cmd_type) {
121 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
122 {
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);
126 goto end_nosignal;
127 }
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
134 DBG("UST Consumer adding channel");
135
136 /* block */
137 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
138 rcu_read_unlock();
139 return -EINTR;
140 }
141 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
142 if (ret != sizeof(fds)) {
143 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
144 rcu_read_unlock();
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) {
155 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
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;
175 struct consumer_relayd_sock_pair *relayd = NULL;
176
177 DBG("UST Consumer adding stream");
178
179 /* block */
180 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
181 rcu_read_unlock();
182 return -EINTR;
183 }
184 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
185 if (ret != sizeof(fds)) {
186 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
187 rcu_read_unlock();
188 return ret;
189 }
190
191 DBG("consumer_add_stream chan %d stream %d",
192 msg.u.stream.channel_key,
193 msg.u.stream.stream_key);
194
195 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
196 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
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,
202 msg.u.stream.path_name,
203 msg.u.stream.uid,
204 msg.u.stream.gid,
205 msg.u.stream.net_index,
206 msg.u.stream.metadata_flag);
207 if (new_stream == NULL) {
208 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
209 goto end_nosignal;
210 }
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) {
222 goto end_nosignal;
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);
228 goto end_nosignal;
229 }
230
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");
246 }
247 } else {
248 if (ctx->on_recv_stream) {
249 ret = ctx->on_recv_stream(new_stream);
250 if (ret < 0) {
251 goto end_nosignal;
252 }
253 }
254 consumer_add_stream(new_stream);
255 }
256
257 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
258 msg.u.stream.path_name, fds[0], fds[1],
259 new_stream->relayd_stream_id);
260 break;
261 }
262 case LTTNG_CONSUMER_DESTROY_RELAYD:
263 {
264 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
265 struct consumer_relayd_sock_pair *relayd;
266
267 DBG("UST consumer destroying relayd %" PRIu64, index);
268
269 /* Get relayd reference if exists. */
270 relayd = consumer_find_relayd(index);
271 if (relayd == NULL) {
272 ERR("Unable to find relayd %" PRIu64, index);
273 goto end_nosignal;
274 }
275
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);
287
288 goto end_nosignal;
289 }
290 case LTTNG_CONSUMER_UPDATE_STREAM:
291 {
292 rcu_read_unlock();
293 return -ENOSYS;
294 #if 0
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;
307 #endif
308 }
309 default:
310 break;
311 }
312
313 /*
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 *
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);
326 } while (ret < 0 && errno == EINTR);
327 end_nosignal:
328 rcu_read_unlock();
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;
335 }
336
337 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
338 {
339 struct lttng_ust_object_data obj;
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 }
349 chan->wait_fd_is_copy = 1;
350 chan->shm_fd = -1;
351
352 return 0;
353 }
354
355 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
356 {
357 ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
358 stream->hangup_flush_done = 1;
359 }
360
361 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
362 {
363 ustctl_unmap_channel(chan->handle);
364 }
365
366 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
367 {
368 struct lttng_ust_object_data obj;
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;
381 /* ustctl_open_stream_read has closed the shm fd. */
382 stream->wait_fd_is_copy = 1;
383 stream->shm_fd = -1;
384
385 stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
386 if (!stream->mmap_base) {
387 return -EINVAL;
388 }
389
390 return 0;
391 }
392
393 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
394 {
395 ustctl_close_stream_read(stream->chan->handle, stream->buf);
396 }
397
398
399 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
400 struct lttng_consumer_local_data *ctx)
401 {
402 unsigned long len, subbuf_size, padding;
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 */
414 if (!stream->hangup_flush_done) {
415 do {
416 readlen = read(stream->wait_fd, &dummy, 1);
417 } while (readlen == -1 && errno == EINTR);
418 if (readlen == -1) {
419 ret = readlen;
420 goto end;
421 }
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) {
429 ret = err; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
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);
441 /* Get the full padded subbuffer size */
442 err = ustctl_get_padded_subbuf_size(handle, buf, &len);
443 assert(err == 0);
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;
453 /* write the subbuffer to the tracefile */
454 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
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)) {
461 /*
462 * Display the error but continue processing to try to release the
463 * subbuffer
464 */
465 ERR("Error writing to tracefile "
466 "(ret: %zd != len: %lu != subbuf_size: %lu)",
467 ret, len, subbuf_size);
468
469 }
470 err = ustctl_put_next_subbuf(handle, buf);
471 assert(err == 0);
472 end:
473 return ret;
474 }
475
476 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
477 {
478 int ret;
479
480 /* Opening the tracefile in write mode */
481 if (stream->path_name != NULL && stream->net_seq_idx == -1) {
482 ret = run_as_open(stream->path_name,
483 O_WRONLY|O_CREAT|O_TRUNC,
484 S_IRWXU|S_IRWXG|S_IRWXO,
485 stream->uid, stream->gid);
486 if (ret < 0) {
487 ERR("Opening %s", stream->path_name);
488 PERROR("open");
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
497 error:
498 return ret;
499 }
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