Implement consumer ring buffer position sampling
[lttng-tools.git] / src / bin / lttng-sessiond / ust-consumer.c
CommitLineData
48842b30
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1/*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
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4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
48842b30 7 *
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8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
48842b30 12 *
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13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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16 */
17
6c1c0768 18#define _LGPL_SOURCE
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19#include <errno.h>
20#include <stdio.h>
21#include <stdlib.h>
22#include <string.h>
23#include <unistd.h>
d88aee68 24#include <inttypes.h>
48842b30 25
990570ed 26#include <common/common.h>
c8fea79c 27#include <common/consumer/consumer.h>
990570ed 28#include <common/defaults.h>
48842b30 29
00e2e675 30#include "consumer.h"
8782cc74 31#include "health-sessiond.h"
48842b30 32#include "ust-consumer.h"
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33#include "buffer-registry.h"
34#include "session.h"
e9404c27 35#include "lttng-sessiond.h"
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36
37/*
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38 * Return allocated full pathname of the session using the consumer trace path
39 * and subdir if available. On a successful allocation, the directory of the
40 * trace is created with the session credentials.
41 *
42 * The caller can safely free(3) the returned value. On error, NULL is
43 * returned.
48842b30 44 */
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45static char *setup_trace_path(struct consumer_output *consumer,
46 struct ust_app_session *ua_sess)
48842b30 47{
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48 int ret;
49 char *pathname;
37278a1e 50
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51 assert(consumer);
52 assert(ua_sess);
00e2e675 53
840cb59c 54 health_code_update();
ca03de58 55
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56 /* Allocate our self the string to make sure we never exceed PATH_MAX. */
57 pathname = zmalloc(PATH_MAX);
58 if (!pathname) {
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59 goto error;
60 }
00e2e675 61
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62 /* Get correct path name destination */
63 if (consumer->type == CONSUMER_DST_LOCAL) {
64 /* Set application path to the destination path */
dec56f6c 65 ret = snprintf(pathname, PATH_MAX, "%s%s%s",
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66 consumer->dst.trace_path, consumer->subdir, ua_sess->path);
67 if (ret < 0) {
68 PERROR("snprintf channel path");
69 goto error;
70 }
ca03de58 71
ffe60014 72 /* Create directory. Ignore if exist. */
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73 ret = run_as_mkdir_recursive(pathname, S_IRWXU | S_IRWXG,
74 ua_sess->euid, ua_sess->egid);
ffe60014 75 if (ret < 0) {
df5b86c8 76 if (errno != EEXIST) {
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77 ERR("Trace directory creation error");
78 goto error;
79 }
80 }
81 } else {
dec56f6c 82 ret = snprintf(pathname, PATH_MAX, "%s%s", consumer->subdir,
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83 ua_sess->path);
84 if (ret < 0) {
85 PERROR("snprintf channel path");
86 goto error;
87 }
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88 }
89
ffe60014 90 return pathname;
ca03de58 91
37278a1e 92error:
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93 free(pathname);
94 return NULL;
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95}
96
97/*
e9404c27 98 * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
ffe60014 99 *
7972aab2 100 * Consumer socket lock MUST be acquired before calling this.
37278a1e 101 */
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102static int ask_channel_creation(struct ust_app_session *ua_sess,
103 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
7972aab2 104 struct consumer_socket *socket, struct ust_registry_session *registry)
37278a1e 105{
0c759fc9 106 int ret, output;
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DG
107 uint32_t chan_id;
108 uint64_t key, chan_reg_key;
ffe60014 109 char *pathname = NULL;
37278a1e 110 struct lttcomm_consumer_msg msg;
7972aab2 111 struct ust_registry_channel *chan_reg;
d7ba1388 112 char shm_path[PATH_MAX] = "";
3d071855 113 char root_shm_path[PATH_MAX] = "";
37278a1e 114
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115 assert(ua_sess);
116 assert(ua_chan);
117 assert(socket);
37278a1e 118 assert(consumer);
7972aab2 119 assert(registry);
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120
121 DBG2("Asking UST consumer for channel");
122
123 /* Get and create full trace path of session. */
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124 if (ua_sess->output_traces) {
125 pathname = setup_trace_path(consumer, ua_sess);
126 if (!pathname) {
127 ret = -1;
128 goto error;
129 }
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130 }
131
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132 /* Depending on the buffer type, a different channel key is used. */
133 if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
134 chan_reg_key = ua_chan->tracing_channel_id;
135 } else {
136 chan_reg_key = ua_chan->key;
137 }
138
139 if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
140 chan_id = -1U;
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141 /*
142 * Metadata channels shm_path (buffers) are handled within
143 * session daemon. Consumer daemon should not try to create
144 * those buffer files.
145 */
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146 } else {
147 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
148 assert(chan_reg);
149 chan_id = chan_reg->chan_id;
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MD
150 if (ua_sess->shm_path[0]) {
151 strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
152 shm_path[sizeof(shm_path) - 1] = '\0';
153 strncat(shm_path, "/",
154 sizeof(shm_path) - strlen(shm_path) - 1);
155 strncat(shm_path, ua_chan->name,
156 sizeof(shm_path) - strlen(shm_path) - 1);
157 strncat(shm_path, "_",
158 sizeof(shm_path) - strlen(shm_path) - 1);
159 }
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MD
160 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
161 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
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162 }
163
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164 switch (ua_chan->attr.output) {
165 case LTTNG_UST_MMAP:
166 default:
167 output = LTTNG_EVENT_MMAP;
168 break;
169 }
170
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171 consumer_init_ask_channel_comm_msg(&msg,
172 ua_chan->attr.subbuf_size,
173 ua_chan->attr.num_subbuf,
174 ua_chan->attr.overwrite,
175 ua_chan->attr.switch_timer_interval,
176 ua_chan->attr.read_timer_interval,
ecc48a90 177 ua_sess->live_timer_interval,
e9404c27 178 ua_chan->monitor_timer_interval,
0c759fc9 179 output,
ffe60014 180 (int) ua_chan->attr.type,
7972aab2 181 ua_sess->tracing_id,
ca22feea 182 pathname,
ffe60014 183 ua_chan->name,
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184 ua_sess->euid,
185 ua_sess->egid,
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186 consumer->net_seq_index,
187 ua_chan->key,
7972aab2 188 registry->uuid,
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189 chan_id,
190 ua_chan->tracefile_size,
2bba9e53 191 ua_chan->tracefile_count,
1950109e 192 ua_sess->id,
567eb353 193 ua_sess->output_traces,
d7ba1388 194 ua_sess->uid,
3d071855 195 root_shm_path, shm_path);
37278a1e 196
840cb59c 197 health_code_update();
ca03de58 198
52898cb1 199 ret = consumer_socket_send(socket, &msg, sizeof(msg));
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200 if (ret < 0) {
201 goto error;
202 }
203
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204 ret = consumer_recv_status_channel(socket, &key,
205 &ua_chan->expected_stream_count);
206 if (ret < 0) {
207 goto error;
208 }
209 /* Communication protocol error. */
210 assert(key == ua_chan->key);
211 /* We need at least one where 1 stream for 1 cpu. */
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212 if (ua_sess->output_traces) {
213 assert(ua_chan->expected_stream_count > 0);
214 }
ffe60014 215
d88aee68 216 DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
ffe60014 217 ua_chan->expected_stream_count);
ca03de58 218
37278a1e 219error:
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220 free(pathname);
221 health_code_update();
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222 return ret;
223}
224
225/*
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226 * Ask consumer to create a channel for a given session.
227 *
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228 * Session list and rcu read side locks must be held by the caller.
229 *
ffe60014 230 * Returns 0 on success else a negative value.
37278a1e 231 */
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232int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
233 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
7972aab2 234 struct consumer_socket *socket, struct ust_registry_session *registry)
37278a1e
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235{
236 int ret;
e9404c27 237 struct ltt_session *session;
37278a1e 238
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239 assert(ua_sess);
240 assert(ua_chan);
241 assert(consumer);
242 assert(socket);
7972aab2 243 assert(registry);
f50f23d9 244
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DG
245 if (!consumer->enabled) {
246 ret = -LTTNG_ERR_NO_CONSUMER;
247 DBG3("Consumer is disabled");
248 goto error;
249 }
250
e9404c27
JG
251 session = session_find_by_id(ua_sess->tracing_id);
252 assert(session);
253
ffe60014 254 pthread_mutex_lock(socket->lock);
7972aab2 255 ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
2898de39 256 pthread_mutex_unlock(socket->lock);
37278a1e 257 if (ret < 0) {
e9404c27 258 ERR("ask_channel_creation consumer command failed");
37278a1e
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259 goto error;
260 }
261
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262error:
263 return ret;
264}
265
266/*
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267 * Send a get channel command to consumer using the given channel key. The
268 * channel object is populated and the stream list.
269 *
270 * Return 0 on success else a negative value.
48842b30 271 */
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272int ust_consumer_get_channel(struct consumer_socket *socket,
273 struct ust_app_channel *ua_chan)
48842b30 274{
ffe60014 275 int ret;
37278a1e 276 struct lttcomm_consumer_msg msg;
48842b30 277
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278 assert(ua_chan);
279 assert(socket);
48842b30 280
53efb85a 281 memset(&msg, 0, sizeof(msg));
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282 msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
283 msg.u.get_channel.key = ua_chan->key;
37278a1e 284
ffe60014 285 pthread_mutex_lock(socket->lock);
840cb59c 286 health_code_update();
ca03de58 287
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288 /* Send command and wait for OK reply. */
289 ret = consumer_send_msg(socket, &msg);
37278a1e
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290 if (ret < 0) {
291 goto error;
292 }
293
ffe60014 294 /* First, get the channel from consumer. */
9363801e 295 ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
37278a1e 296 if (ret < 0) {
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297 if (ret != -EPIPE) {
298 ERR("Error recv channel from consumer %d with ret %d",
9363801e 299 *socket->fd_ptr, ret);
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300 } else {
301 DBG3("UST app recv channel from consumer. Consumer is dead.");
302 }
37278a1e
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303 goto error;
304 }
00e2e675 305
ffe60014
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306 /* Next, get all streams. */
307 while (1) {
308 struct ust_app_stream *stream;
ca03de58 309
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310 /* Create UST stream */
311 stream = ust_app_alloc_stream();
312 if (stream == NULL) {
313 ret = -ENOMEM;
48842b30
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314 goto error;
315 }
316
ffe60014 317 /* Stream object is populated by this call if successful. */
9363801e 318 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
37278a1e 319 if (ret < 0) {
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DG
320 free(stream);
321 if (ret == -LTTNG_UST_ERR_NOENT) {
322 DBG3("UST app consumer has no more stream available");
323 ret = 0;
324 break;
325 }
326 if (ret != -EPIPE) {
327 ERR("Recv stream from consumer %d with ret %d",
9363801e 328 *socket->fd_ptr, ret);
ffe60014
DG
329 } else {
330 DBG3("UST app recv stream from consumer. Consumer is dead.");
00e2e675 331 }
48842b30
DG
332 goto error;
333 }
37278a1e 334
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335 /* Order is important this is why a list is used. */
336 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
337 ua_chan->streams.count++;
37278a1e 338
5368d366 339 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
ffe60014
DG
340 }
341
342 /* This MUST match or else we have a synchronization problem. */
343 assert(ua_chan->expected_stream_count == ua_chan->streams.count);
ca03de58 344
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345 /* Wait for confirmation that we can proceed with the streams. */
346 ret = consumer_recv_status_reply(socket);
37278a1e
DG
347 if (ret < 0) {
348 goto error;
349 }
350
351error:
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352 health_code_update();
353 pthread_mutex_unlock(socket->lock);
37278a1e
DG
354 return ret;
355}
356
357/*
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358 * Send a destroy channel command to consumer using the given channel key.
359 *
360 * Note that this command MUST be used prior to a successful
361 * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
362 * the streams are dispatched to the consumer threads and MUST be teardown
363 * through the hang up process.
364 *
365 * Return 0 on success else a negative value.
37278a1e 366 */
ffe60014
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367int ust_consumer_destroy_channel(struct consumer_socket *socket,
368 struct ust_app_channel *ua_chan)
37278a1e 369{
ffe60014
DG
370 int ret;
371 struct lttcomm_consumer_msg msg;
a4b92340 372
ffe60014
DG
373 assert(ua_chan);
374 assert(socket);
37278a1e 375
53efb85a 376 memset(&msg, 0, sizeof(msg));
ffe60014
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377 msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
378 msg.u.destroy_channel.key = ua_chan->key;
173af62f 379
ffe60014
DG
380 pthread_mutex_lock(socket->lock);
381 health_code_update();
37278a1e 382
ffe60014 383 ret = consumer_send_msg(socket, &msg);
37278a1e
DG
384 if (ret < 0) {
385 goto error;
48842b30
DG
386 }
387
ffe60014
DG
388error:
389 health_code_update();
390 pthread_mutex_unlock(socket->lock);
391 return ret;
392}
aeb96892 393
ffe60014
DG
394/*
395 * Send a given stream to UST tracer.
396 *
397 * On success return 0 else a negative value.
398 */
399int ust_consumer_send_stream_to_ust(struct ust_app *app,
400 struct ust_app_channel *channel, struct ust_app_stream *stream)
401{
402 int ret;
403
404 assert(app);
405 assert(stream);
406 assert(channel);
407
408 DBG2("UST consumer send stream to app %d", app->sock);
409
410 /* Relay stream to application. */
fb45065e 411 pthread_mutex_lock(&app->sock_lock);
ffe60014 412 ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
fb45065e 413 pthread_mutex_unlock(&app->sock_lock);
ffe60014
DG
414 if (ret < 0) {
415 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
8cf93def
DG
416 ERR("ustctl send stream handle %d to app pid: %d with ret %d",
417 stream->obj->handle, app->pid, ret);
ffe60014
DG
418 } else {
419 DBG3("UST app send stream to ust failed. Application is dead.");
48842b30 420 }
ffe60014 421 goto error;
48842b30 422 }
d0b96690 423 channel->handle = channel->obj->handle;
48842b30 424
ffe60014
DG
425error:
426 return ret;
427}
428
429/*
430 * Send channel previously received from the consumer to the UST tracer.
431 *
432 * On success return 0 else a negative value.
433 */
434int ust_consumer_send_channel_to_ust(struct ust_app *app,
435 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
436{
437 int ret;
438
439 assert(app);
440 assert(ua_sess);
441 assert(channel);
442 assert(channel->obj);
443
7972aab2
DG
444 DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
445 app->sock, app->pid, channel->name, channel->tracing_channel_id);
48842b30 446
ffe60014 447 /* Send stream to application. */
fb45065e 448 pthread_mutex_lock(&app->sock_lock);
ffe60014 449 ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
fb45065e 450 pthread_mutex_unlock(&app->sock_lock);
ffe60014
DG
451 if (ret < 0) {
452 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
453 ERR("Error ustctl send channel %s to app pid: %d with ret %d",
454 channel->name, app->pid, ret);
455 } else {
456 DBG3("UST app send channel to ust failed. Application is dead.");
457 }
458 goto error;
459 }
48842b30
DG
460
461error:
462 return ret;
463}
331744e3
JD
464
465/*
466 * Handle the metadata requests from the UST consumer
467 *
468 * Return 0 on success else a negative value.
469 */
470int ust_consumer_metadata_request(struct consumer_socket *socket)
471{
472 int ret;
473 ssize_t ret_push;
474 struct lttcomm_metadata_request_msg request;
475 struct buffer_reg_uid *reg_uid;
476 struct ust_registry_session *ust_reg;
477 struct lttcomm_consumer_msg msg;
478
479 assert(socket);
480
481 rcu_read_lock();
331744e3
JD
482 health_code_update();
483
484 /* Wait for a metadata request */
dc2bbdae 485 pthread_mutex_lock(socket->lock);
52898cb1 486 ret = consumer_socket_recv(socket, &request, sizeof(request));
dc2bbdae 487 pthread_mutex_unlock(socket->lock);
52898cb1 488 if (ret < 0) {
331744e3
JD
489 goto end;
490 }
491
1950109e 492 DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
331744e3
JD
493 request.session_id, request.key);
494
495 reg_uid = buffer_reg_uid_find(request.session_id,
496 request.bits_per_long, request.uid);
497 if (reg_uid) {
498 ust_reg = reg_uid->registry->reg.ust;
499 } else {
500 struct buffer_reg_pid *reg_pid =
1950109e 501 buffer_reg_pid_find(request.session_id_per_pid);
331744e3 502 if (!reg_pid) {
1950109e
JD
503 DBG("PID registry not found for session id %" PRIu64,
504 request.session_id_per_pid);
331744e3 505
53efb85a 506 memset(&msg, 0, sizeof(msg));
331744e3
JD
507 msg.cmd_type = LTTNG_ERR_UND;
508 (void) consumer_send_msg(socket, &msg);
509 /*
510 * This is possible since the session might have been destroyed
511 * during a consumer metadata request. So here, return gracefully
512 * because the destroy session will push the remaining metadata to
513 * the consumer.
514 */
515 ret = 0;
516 goto end;
517 }
518 ust_reg = reg_pid->registry->reg.ust;
519 }
520 assert(ust_reg);
521
dc2bbdae 522 pthread_mutex_lock(&ust_reg->lock);
331744e3 523 ret_push = ust_app_push_metadata(ust_reg, socket, 1);
dc2bbdae 524 pthread_mutex_unlock(&ust_reg->lock);
2c57e06d
MD
525 if (ret_push == -EPIPE) {
526 DBG("Application or relay closed while pushing metadata");
527 } else if (ret_push < 0) {
331744e3
JD
528 ERR("Pushing metadata");
529 ret = -1;
530 goto end;
2c57e06d
MD
531 } else {
532 DBG("UST Consumer metadata pushed successfully");
331744e3 533 }
331744e3
JD
534 ret = 0;
535
536end:
331744e3
JD
537 rcu_read_unlock();
538 return ret;
539}
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