src/bin/lttng-sessiond/ust-consumer.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   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.
   7  *
   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.
  12  *
  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.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <errno.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <inttypes.h>
  25
  26 #include <common/common.h>
  27 #include <common/consumer/consumer.h>
  28 #include <common/defaults.h>
  29
  30 #include "consumer.h"
  31 #include "health-sessiond.h"
  32 #include "ust-consumer.h"
  33 #include "buffer-registry.h"
  34 #include "session.h"
  35 #include "lttng-sessiond.h"
  36
  37 /*
  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.
  44  */
  45 static char *setup_trace_path(struct consumer_output *consumer,
  46                 struct ust_app_session *ua_sess)
  47 {
  48         int ret;
  49         char *pathname;
  50
  51         assert(consumer);
  52         assert(ua_sess);
  53
  54         health_code_update();
  55
  56         /* Allocate our self the string to make sure we never exceed PATH_MAX. */
  57         pathname = zmalloc(PATH_MAX);
  58         if (!pathname) {
  59                 goto error;
  60         }
  61
  62         /* Get correct path name destination */
  63         if (consumer->type == CONSUMER_DST_LOCAL) {
  64                 /* Set application path to the destination path */
  65                 ret = snprintf(pathname, PATH_MAX, "%s%s%s%s",
  66                                 consumer->dst.session_root_path,
  67                                 consumer->chunk_path,
  68                                 consumer->subdir, ua_sess->path);
  69                 if (ret < 0) {
  70                         PERROR("snprintf channel path");
  71                         goto error;
  72                 }
  73
  74                 /* Create directory. Ignore if exist. */
  75                 ret = run_as_mkdir_recursive(pathname, S_IRWXU | S_IRWXG,
  76                                 ua_sess->euid, ua_sess->egid);
  77                 if (ret < 0) {
  78                         if (errno != EEXIST) {
  79                                 ERR("Trace directory creation error");
  80                                 goto error;
  81                         }
  82                 }
  83         } else {
  84                 ret = snprintf(pathname, PATH_MAX, "%s%s%s%s",
  85                                 consumer->dst.net.base_dir,
  86                                 consumer->chunk_path,
  87                                 consumer->subdir,
  88                                 ua_sess->path);
  89                 if (ret < 0) {
  90                         PERROR("snprintf channel path");
  91                         goto error;
  92                 }
  93         }
  94
  95         return pathname;
  96
  97 error:
  98         free(pathname);
  99         return NULL;
 100 }
 101
 102 /*
 103  * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
 104  *
 105  * Consumer socket lock MUST be acquired before calling this.
 106  */
 107 static int ask_channel_creation(struct ust_app_session *ua_sess,
 108                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 109                 struct consumer_socket *socket, struct ust_registry_session *registry)
 110 {
 111         int ret, output;
 112         uint32_t chan_id;
 113         uint64_t key, chan_reg_key;
 114         char *pathname = NULL;
 115         struct lttcomm_consumer_msg msg;
 116         struct ust_registry_channel *chan_reg;
 117         char shm_path[PATH_MAX] = "";
 118         char root_shm_path[PATH_MAX] = "";
 119
 120         assert(ua_sess);
 121         assert(ua_chan);
 122         assert(socket);
 123         assert(consumer);
 124         assert(registry);
 125
 126         DBG2("Asking UST consumer for channel");
 127
 128         /* Get and create full trace path of session. */
 129         if (ua_sess->output_traces) {
 130                 pathname = setup_trace_path(consumer, ua_sess);
 131                 if (!pathname) {
 132                         ret = -1;
 133                         goto error;
 134                 }
 135         }
 136
 137         /* Depending on the buffer type, a different channel key is used. */
 138         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 139                 chan_reg_key = ua_chan->tracing_channel_id;
 140         } else {
 141                 chan_reg_key = ua_chan->key;
 142         }
 143
 144         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 145                 chan_id = -1U;
 146                 /*
 147                  * Metadata channels shm_path (buffers) are handled within
 148                  * session daemon. Consumer daemon should not try to create
 149                  * those buffer files.
 150                  */
 151         } else {
 152                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 153                 assert(chan_reg);
 154                 chan_id = chan_reg->chan_id;
 155                 if (ua_sess->shm_path[0]) {
 156                         strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
 157                         shm_path[sizeof(shm_path) - 1] = '\0';
 158                         strncat(shm_path, "/",
 159                                 sizeof(shm_path) - strlen(shm_path) - 1);
 160                         strncat(shm_path, ua_chan->name,
 161                                         sizeof(shm_path) - strlen(shm_path) - 1);
 162                                 strncat(shm_path, "_",
 163                                         sizeof(shm_path) - strlen(shm_path) - 1);
 164                 }
 165                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 166                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 167         }
 168
 169         switch (ua_chan->attr.output) {
 170         case LTTNG_UST_MMAP:
 171         default:
 172                 output = LTTNG_EVENT_MMAP;
 173                 break;
 174         }
 175
 176         consumer_init_ask_channel_comm_msg(&msg,
 177                         ua_chan->attr.subbuf_size,
 178                         ua_chan->attr.num_subbuf,
 179                         ua_chan->attr.overwrite,
 180                         ua_chan->attr.switch_timer_interval,
 181                         ua_chan->attr.read_timer_interval,
 182                         ua_sess->live_timer_interval,
 183                         ua_chan->monitor_timer_interval,
 184                         output,
 185                         (int) ua_chan->attr.type,
 186                         ua_sess->tracing_id,
 187                         pathname,
 188                         ua_chan->name,
 189                         ua_sess->euid,
 190                         ua_sess->egid,
 191                         consumer->net_seq_index,
 192                         ua_chan->key,
 193                         registry->uuid,
 194                         chan_id,
 195                         ua_chan->tracefile_size,
 196                         ua_chan->tracefile_count,
 197                         ua_sess->id,
 198                         ua_sess->output_traces,
 199                         ua_sess->uid,
 200                         ua_chan->attr.blocking_timeout,
 201                         root_shm_path, shm_path);
 202
 203         health_code_update();
 204
 205         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 206         if (ret < 0) {
 207                 goto error;
 208         }
 209
 210         ret = consumer_recv_status_channel(socket, &key,
 211                         &ua_chan->expected_stream_count);
 212         if (ret < 0) {
 213                 goto error;
 214         }
 215         /* Communication protocol error. */
 216         assert(key == ua_chan->key);
 217         /* We need at least one where 1 stream for 1 cpu. */
 218         if (ua_sess->output_traces) {
 219                 assert(ua_chan->expected_stream_count > 0);
 220         }
 221
 222         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 223                         ua_chan->expected_stream_count);
 224
 225 error:
 226         free(pathname);
 227         health_code_update();
 228         return ret;
 229 }
 230
 231 /*
 232  * Ask consumer to create a channel for a given session.
 233  *
 234  * Session list and rcu read side locks must be held by the caller.
 235  *
 236  * Returns 0 on success else a negative value.
 237  */
 238 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 239                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 240                 struct consumer_socket *socket, struct ust_registry_session *registry)
 241 {
 242         int ret;
 243         struct ltt_session *session;
 244
 245         assert(ua_sess);
 246         assert(ua_chan);
 247         assert(consumer);
 248         assert(socket);
 249         assert(registry);
 250
 251         if (!consumer->enabled) {
 252                 ret = -LTTNG_ERR_NO_CONSUMER;
 253                 DBG3("Consumer is disabled");
 254                 goto error;
 255         }
 256
 257         session = session_find_by_id(ua_sess->tracing_id);
 258         assert(session);
 259
 260         pthread_mutex_lock(socket->lock);
 261         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 262         pthread_mutex_unlock(socket->lock);
 263         if (ret < 0) {
 264                 ERR("ask_channel_creation consumer command failed");
 265                 goto error;
 266         }
 267
 268 error:
 269         return ret;
 270 }
 271
 272 /*
 273  * Send a get channel command to consumer using the given channel key.  The
 274  * channel object is populated and the stream list.
 275  *
 276  * Return 0 on success else a negative value.
 277  */
 278 int ust_consumer_get_channel(struct consumer_socket *socket,
 279                 struct ust_app_channel *ua_chan)
 280 {
 281         int ret;
 282         struct lttcomm_consumer_msg msg;
 283
 284         assert(ua_chan);
 285         assert(socket);
 286
 287         memset(&msg, 0, sizeof(msg));
 288         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 289         msg.u.get_channel.key = ua_chan->key;
 290
 291         pthread_mutex_lock(socket->lock);
 292         health_code_update();
 293
 294         /* Send command and wait for OK reply. */
 295         ret = consumer_send_msg(socket, &msg);
 296         if (ret < 0) {
 297                 goto error;
 298         }
 299
 300         /* First, get the channel from consumer. */
 301         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 302         if (ret < 0) {
 303                 if (ret != -EPIPE) {
 304                         ERR("Error recv channel from consumer %d with ret %d",
 305                                         *socket->fd_ptr, ret);
 306                 } else {
 307                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 308                 }
 309                 goto error;
 310         }
 311
 312         /* Next, get all streams. */
 313         while (1) {
 314                 struct ust_app_stream *stream;
 315
 316                 /* Create UST stream */
 317                 stream = ust_app_alloc_stream();
 318                 if (stream == NULL) {
 319                         ret = -ENOMEM;
 320                         goto error;
 321                 }
 322
 323                 /* Stream object is populated by this call if successful. */
 324                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 325                 if (ret < 0) {
 326                         free(stream);
 327                         if (ret == -LTTNG_UST_ERR_NOENT) {
 328                                 DBG3("UST app consumer has no more stream available");
 329                                 break;
 330                         }
 331                         if (ret != -EPIPE) {
 332                                 ERR("Recv stream from consumer %d with ret %d",
 333                                                 *socket->fd_ptr, ret);
 334                         } else {
 335                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 336                         }
 337                         goto error;
 338                 }
 339
 340                 /* Order is important this is why a list is used. */
 341                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 342                 ua_chan->streams.count++;
 343
 344                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 345         }
 346
 347         /* This MUST match or else we have a synchronization problem. */
 348         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 349
 350         /* Wait for confirmation that we can proceed with the streams. */
 351         ret = consumer_recv_status_reply(socket);
 352         if (ret < 0) {
 353                 goto error;
 354         }
 355
 356 error:
 357         health_code_update();
 358         pthread_mutex_unlock(socket->lock);
 359         return ret;
 360 }
 361
 362 /*
 363  * Send a destroy channel command to consumer using the given channel key.
 364  *
 365  * Note that this command MUST be used prior to a successful
 366  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 367  * the streams are dispatched to the consumer threads and MUST be teardown
 368  * through the hang up process.
 369  *
 370  * Return 0 on success else a negative value.
 371  */
 372 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 373                 struct ust_app_channel *ua_chan)
 374 {
 375         int ret;
 376         struct lttcomm_consumer_msg msg;
 377
 378         assert(ua_chan);
 379         assert(socket);
 380
 381         memset(&msg, 0, sizeof(msg));
 382         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 383         msg.u.destroy_channel.key = ua_chan->key;
 384
 385         pthread_mutex_lock(socket->lock);
 386         health_code_update();
 387
 388         ret = consumer_send_msg(socket, &msg);
 389         if (ret < 0) {
 390                 goto error;
 391         }
 392
 393 error:
 394         health_code_update();
 395         pthread_mutex_unlock(socket->lock);
 396         return ret;
 397 }
 398
 399 /*
 400  * Send a given stream to UST tracer.
 401  *
 402  * On success return 0 else a negative value.
 403  */
 404 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 405                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 406 {
 407         int ret;
 408
 409         assert(app);
 410         assert(stream);
 411         assert(channel);
 412
 413         DBG2("UST consumer send stream to app %d", app->sock);
 414
 415         /* Relay stream to application. */
 416         pthread_mutex_lock(&app->sock_lock);
 417         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 418         pthread_mutex_unlock(&app->sock_lock);
 419         if (ret < 0) {
 420                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 421                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 422                                         stream->obj->handle, app->pid, ret);
 423                 } else {
 424                         DBG3("UST app send stream to ust failed. Application is dead.");
 425                 }
 426                 goto error;
 427         }
 428         channel->handle = channel->obj->handle;
 429
 430 error:
 431         return ret;
 432 }
 433
 434 /*
 435  * Send channel previously received from the consumer to the UST tracer.
 436  *
 437  * On success return 0 else a negative value.
 438  */
 439 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 440                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 441 {
 442         int ret;
 443
 444         assert(app);
 445         assert(ua_sess);
 446         assert(channel);
 447         assert(channel->obj);
 448
 449         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 450                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 451
 452         /* Send stream to application. */
 453         pthread_mutex_lock(&app->sock_lock);
 454         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 455         pthread_mutex_unlock(&app->sock_lock);
 456         if (ret < 0) {
 457                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 458                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 459                                         channel->name, app->pid, ret);
 460                 } else {
 461                         DBG3("UST app send channel to ust failed. Application is dead.");
 462                 }
 463                 goto error;
 464         }
 465
 466 error:
 467         return ret;
 468 }
 469
 470 /*
 471  * Handle the metadata requests from the UST consumer
 472  *
 473  * Return 0 on success else a negative value.
 474  */
 475 int ust_consumer_metadata_request(struct consumer_socket *socket)
 476 {
 477         int ret;
 478         ssize_t ret_push;
 479         struct lttcomm_metadata_request_msg request;
 480         struct buffer_reg_uid *reg_uid;
 481         struct ust_registry_session *ust_reg;
 482         struct lttcomm_consumer_msg msg;
 483
 484         assert(socket);
 485
 486         rcu_read_lock();
 487         health_code_update();
 488
 489         /* Wait for a metadata request */
 490         pthread_mutex_lock(socket->lock);
 491         ret = consumer_socket_recv(socket, &request, sizeof(request));
 492         pthread_mutex_unlock(socket->lock);
 493         if (ret < 0) {
 494                 goto end;
 495         }
 496
 497         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 498                         request.session_id, request.key);
 499
 500         reg_uid = buffer_reg_uid_find(request.session_id,
 501                         request.bits_per_long, request.uid);
 502         if (reg_uid) {
 503                 ust_reg = reg_uid->registry->reg.ust;
 504         } else {
 505                 struct buffer_reg_pid *reg_pid =
 506                         buffer_reg_pid_find(request.session_id_per_pid);
 507                 if (!reg_pid) {
 508                         DBG("PID registry not found for session id %" PRIu64,
 509                                         request.session_id_per_pid);
 510
 511                         memset(&msg, 0, sizeof(msg));
 512                         msg.cmd_type = LTTNG_ERR_UND;
 513                         (void) consumer_send_msg(socket, &msg);
 514                         /*
 515                          * This is possible since the session might have been destroyed
 516                          * during a consumer metadata request. So here, return gracefully
 517                          * because the destroy session will push the remaining metadata to
 518                          * the consumer.
 519                          */
 520                         ret = 0;
 521                         goto end;
 522                 }
 523                 ust_reg = reg_pid->registry->reg.ust;
 524         }
 525         assert(ust_reg);
 526
 527         pthread_mutex_lock(&ust_reg->lock);
 528         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 529         pthread_mutex_unlock(&ust_reg->lock);
 530         if (ret_push == -EPIPE) {
 531                 DBG("Application or relay closed while pushing metadata");
 532         } else if (ret_push < 0) {
 533                 ERR("Pushing metadata");
 534                 ret = -1;
 535                 goto end;
 536         } else {
 537                 DBG("UST Consumer metadata pushed successfully");
 538         }
 539         ret = 0;
 540
 541 end:
 542         rcu_read_unlock();
 543         return ret;
 544 }