Fix: consumer recv command error path
[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 if (ctx->on_recv_stream != NULL) {
232 ret = ctx->on_recv_stream(new_stream);
233 if (ret == 0) {
234 consumer_add_stream(new_stream);
235 } else if (ret < 0) {
236 goto end_nosignal;
237 }
238 } else {
239 consumer_add_stream(new_stream);
240 }
241
242 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
243 msg.u.stream.path_name, fds[0], fds[1],
244 new_stream->relayd_stream_id);
245 break;
246 }
247 case LTTNG_CONSUMER_DESTROY_RELAYD:
248 {
249 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
250 struct consumer_relayd_sock_pair *relayd;
251
252 DBG("UST consumer destroying relayd %" PRIu64, index);
253
254 /* Get relayd reference if exists. */
255 relayd = consumer_find_relayd(index);
256 if (relayd == NULL) {
257 ERR("Unable to find relayd %" PRIu64, index);
258 goto end_nosignal;
259 }
260
261 /*
262 * Each relayd socket pair has a refcount of stream attached to it
263 * which tells if the relayd is still active or not depending on the
264 * refcount value.
265 *
266 * This will set the destroy flag of the relayd object and destroy it
267 * if the refcount reaches zero when called.
268 *
269 * The destroy can happen either here or when a stream fd hangs up.
270 */
271 consumer_flag_relayd_for_destroy(relayd);
272
273 goto end_nosignal;
274 }
275 case LTTNG_CONSUMER_UPDATE_STREAM:
276 {
277 rcu_read_unlock();
278 return -ENOSYS;
279 #if 0
280 if (ctx->on_update_stream != NULL) {
281 ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
282 if (ret == 0) {
283 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
284 } else if (ret < 0) {
285 goto end;
286 }
287 } else {
288 consumer_change_stream_state(msg.u.stream.stream_key,
289 msg.u.stream.state);
290 }
291 break;
292 #endif
293 }
294 default:
295 break;
296 }
297
298 /*
299 * Wake-up the other end by writing a null byte in the pipe (non-blocking).
300 * Important note: Because writing into the pipe is non-blocking (and
301 * therefore we allow dropping wakeup data, as long as there is wakeup data
302 * present in the pipe buffer to wake up the other end), the other end
303 * should perform the following sequence for waiting:
304 *
305 * 1) empty the pipe (reads).
306 * 2) perform update operation.
307 * 3) wait on the pipe (poll).
308 */
309 do {
310 ret = write(ctx->consumer_poll_pipe[1], "", 1);
311 } while (ret < 0 && errno == EINTR);
312 end_nosignal:
313 rcu_read_unlock();
314
315 /*
316 * Return 1 to indicate success since the 0 value can be a socket
317 * shutdown during the recv() or send() call.
318 */
319 return 1;
320 }
321
322 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
323 {
324 struct lttng_ust_object_data obj;
325
326 obj.handle = -1;
327 obj.shm_fd = chan->shm_fd;
328 obj.wait_fd = chan->wait_fd;
329 obj.memory_map_size = chan->mmap_len;
330 chan->handle = ustctl_map_channel(&obj);
331 if (!chan->handle) {
332 return -ENOMEM;
333 }
334 chan->wait_fd_is_copy = 1;
335 chan->shm_fd = -1;
336
337 return 0;
338 }
339
340 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
341 {
342 ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
343 stream->hangup_flush_done = 1;
344 }
345
346 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
347 {
348 ustctl_unmap_channel(chan->handle);
349 }
350
351 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
352 {
353 struct lttng_ust_object_data obj;
354 int ret;
355
356 obj.handle = -1;
357 obj.shm_fd = stream->shm_fd;
358 obj.wait_fd = stream->wait_fd;
359 obj.memory_map_size = stream->mmap_len;
360 ret = ustctl_add_stream(stream->chan->handle, &obj);
361 if (ret)
362 return ret;
363 stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
364 if (!stream->buf)
365 return -EBUSY;
366 /* ustctl_open_stream_read has closed the shm fd. */
367 stream->wait_fd_is_copy = 1;
368 stream->shm_fd = -1;
369
370 stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
371 if (!stream->mmap_base) {
372 return -EINVAL;
373 }
374
375 return 0;
376 }
377
378 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
379 {
380 ustctl_close_stream_read(stream->chan->handle, stream->buf);
381 }
382
383
384 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
385 struct lttng_consumer_local_data *ctx)
386 {
387 unsigned long len;
388 int err;
389 long ret = 0;
390 struct lttng_ust_shm_handle *handle;
391 struct lttng_ust_lib_ring_buffer *buf;
392 char dummy;
393 ssize_t readlen;
394
395 DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
396 stream->wait_fd, stream->key);
397
398 /* We can consume the 1 byte written into the wait_fd by UST */
399 if (!stream->hangup_flush_done) {
400 do {
401 readlen = read(stream->wait_fd, &dummy, 1);
402 } while (readlen == -1 && errno == EINTR);
403 if (readlen == -1) {
404 ret = readlen;
405 goto end;
406 }
407 }
408
409 buf = stream->buf;
410 handle = stream->chan->handle;
411 /* Get the next subbuffer */
412 err = ustctl_get_next_subbuf(handle, buf);
413 if (err != 0) {
414 ret = -ret; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
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 assert(stream->output == LTTNG_EVENT_MMAP);
426 /* read the used subbuffer size */
427 err = ustctl_get_padded_subbuf_size(handle, buf, &len);
428 assert(err == 0);
429 /* write the subbuffer to the tracefile */
430 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
431 if (ret != len) {
432 /*
433 * display the error but continue processing to try
434 * to release the subbuffer
435 */
436 ERR("Error writing to tracefile (expected: %ld, got: %ld)", ret, len);
437 }
438 err = ustctl_put_next_subbuf(handle, buf);
439 assert(err == 0);
440 end:
441 return ret;
442 }
443
444 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
445 {
446 int ret;
447
448 /* Opening the tracefile in write mode */
449 if (stream->path_name != NULL && stream->net_seq_idx == -1) {
450 ret = run_as_open(stream->path_name,
451 O_WRONLY|O_CREAT|O_TRUNC,
452 S_IRWXU|S_IRWXG|S_IRWXO,
453 stream->uid, stream->gid);
454 if (ret < 0) {
455 ERR("Opening %s", stream->path_name);
456 PERROR("open");
457 goto error;
458 }
459 stream->out_fd = ret;
460 }
461
462 /* we return 0 to let the library handle the FD internally */
463 return 0;
464
465 error:
466 return ret;
467 }
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