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.
  40  *
  41  * The caller can safely free(3) the returned value. On error, NULL is
  42  * returned.
  43  */
  44 static char *setup_channel_trace_path(struct consumer_output *consumer,
  45                 struct ust_app_session *ua_sess)
  46 {
  47         int ret;
  48         char *pathname;
  49
  50         assert(consumer);
  51         assert(ua_sess);
  52
  53         health_code_update();
  54
  55         /*
  56          * Allocate the string ourself to make sure we never exceed
  57          * LTTNG_PATH_MAX.
  58          */
  59         pathname = zmalloc(LTTNG_PATH_MAX);
  60         if (!pathname) {
  61                 goto error;
  62         }
  63
  64         /* Get correct path name destination */
  65         if (consumer->type == CONSUMER_DST_LOCAL) {
  66                 /* Set application path to the destination path */
  67                 ret = snprintf(pathname, LTTNG_PATH_MAX, "%s%s",
  68                                 consumer->domain_subdir, ua_sess->path);
  69                 DBG3("Userspace local consumer trace path relative to current trace chunk: \"%s\"",
  70                                 pathname);
  71         } else {
  72                 ret = snprintf(pathname, LTTNG_PATH_MAX, "%s%s/%s%s",
  73                                 consumer->dst.net.base_dir,
  74                                 consumer->chunk_path,
  75                                 consumer->domain_subdir,
  76                                 ua_sess->path);
  77         }
  78         if (ret < 0) {
  79                 PERROR("Failed to format channel path");
  80                 goto error;
  81         } else if (ret >= LTTNG_PATH_MAX) {
  82                 ERR("Truncation occurred while formatting channel path");
  83                 ret = -1;
  84                 goto error;
  85         }
  86
  87         return pathname;
  88
  89 error:
  90         free(pathname);
  91         return NULL;
  92 }
  93
  94 /*
  95  * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
  96  *
  97  * Consumer socket lock MUST be acquired before calling this.
  98  */
  99 static int ask_channel_creation(struct ust_app_session *ua_sess,
 100                 struct ust_app_channel *ua_chan,
 101                 struct consumer_output *consumer,
 102                 struct consumer_socket *socket,
 103                 struct ust_registry_session *registry,
 104                 struct lttng_trace_chunk *trace_chunk)
 105 {
 106         int ret, output;
 107         uint32_t chan_id;
 108         uint64_t key, chan_reg_key;
 109         char *pathname = NULL;
 110         struct lttcomm_consumer_msg msg;
 111         struct ust_registry_channel *chan_reg;
 112         char shm_path[PATH_MAX] = "";
 113         char root_shm_path[PATH_MAX] = "";
 114         bool is_local_trace;
 115
 116         assert(ua_sess);
 117         assert(ua_chan);
 118         assert(socket);
 119         assert(consumer);
 120         assert(registry);
 121
 122         DBG2("Asking UST consumer for channel");
 123
 124         is_local_trace = consumer->net_seq_index == -1ULL;
 125         /* Format the channel's path (relative to the current trace chunk). */
 126         pathname = setup_channel_trace_path(consumer, ua_sess);
 127         if (!pathname) {
 128                 ret = -1;
 129                 goto error;
 130         }
 131
 132         if (is_local_trace && trace_chunk) {
 133                 enum lttng_trace_chunk_status chunk_status;
 134                 char *pathname_index;
 135
 136                 ret = asprintf(&pathname_index, "%s/" DEFAULT_INDEX_DIR,
 137                                 pathname);
 138                 if (ret < 0) {
 139                         ERR("Failed to format channel index directory");
 140                         ret = -1;
 141                         goto error;
 142                 }
 143
 144                 /*
 145                  * Create the index subdirectory which will take care
 146                  * of implicitly creating the channel's path.
 147                  */
 148                 chunk_status = lttng_trace_chunk_create_subdirectory(
 149                                 trace_chunk, pathname_index);
 150                 free(pathname_index);
 151                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 152                         ret = -1;
 153                         goto error;
 154                 }
 155         }
 156
 157         /* Depending on the buffer type, a different channel key is used. */
 158         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 159                 chan_reg_key = ua_chan->tracing_channel_id;
 160         } else {
 161                 chan_reg_key = ua_chan->key;
 162         }
 163
 164         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 165                 chan_id = -1U;
 166                 /*
 167                  * Metadata channels shm_path (buffers) are handled within
 168                  * session daemon. Consumer daemon should not try to create
 169                  * those buffer files.
 170                  */
 171         } else {
 172                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 173                 assert(chan_reg);
 174                 chan_id = chan_reg->chan_id;
 175                 if (ua_sess->shm_path[0]) {
 176                         strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
 177                         shm_path[sizeof(shm_path) - 1] = '\0';
 178                         strncat(shm_path, "/",
 179                                 sizeof(shm_path) - strlen(shm_path) - 1);
 180                         strncat(shm_path, ua_chan->name,
 181                                         sizeof(shm_path) - strlen(shm_path) - 1);
 182                                 strncat(shm_path, "_",
 183                                         sizeof(shm_path) - strlen(shm_path) - 1);
 184                 }
 185                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 186                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 187         }
 188
 189         switch (ua_chan->attr.output) {
 190         case LTTNG_UST_MMAP:
 191         default:
 192                 output = LTTNG_EVENT_MMAP;
 193                 break;
 194         }
 195
 196         consumer_init_ask_channel_comm_msg(&msg,
 197                         ua_chan->attr.subbuf_size,
 198                         ua_chan->attr.num_subbuf,
 199                         ua_chan->attr.overwrite,
 200                         ua_chan->attr.switch_timer_interval,
 201                         ua_chan->attr.read_timer_interval,
 202                         ua_sess->live_timer_interval,
 203                         ua_chan->monitor_timer_interval,
 204                         output,
 205                         (int) ua_chan->attr.type,
 206                         ua_sess->tracing_id,
 207                         pathname,
 208                         ua_chan->name,
 209                         consumer->net_seq_index,
 210                         ua_chan->key,
 211                         registry->uuid,
 212                         chan_id,
 213                         ua_chan->tracefile_size,
 214                         ua_chan->tracefile_count,
 215                         ua_sess->id,
 216                         ua_sess->output_traces,
 217                         ua_sess->real_credentials.uid,
 218                         ua_chan->attr.blocking_timeout,
 219                         root_shm_path, shm_path,
 220                         trace_chunk,
 221                         &ua_sess->effective_credentials);
 222
 223         health_code_update();
 224
 225         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 226         if (ret < 0) {
 227                 goto error;
 228         }
 229
 230         ret = consumer_recv_status_channel(socket, &key,
 231                         &ua_chan->expected_stream_count);
 232         if (ret < 0) {
 233                 goto error;
 234         }
 235         /* Communication protocol error. */
 236         assert(key == ua_chan->key);
 237         /* We need at least one where 1 stream for 1 cpu. */
 238         if (ua_sess->output_traces) {
 239                 assert(ua_chan->expected_stream_count > 0);
 240         }
 241
 242         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 243                         ua_chan->expected_stream_count);
 244
 245 error:
 246         free(pathname);
 247         health_code_update();
 248         return ret;
 249 }
 250
 251 /*
 252  * Ask consumer to create a channel for a given session.
 253  *
 254  * Session list and rcu read side locks must be held by the caller.
 255  *
 256  * Returns 0 on success else a negative value.
 257  */
 258 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 259                 struct ust_app_channel *ua_chan,
 260                 struct consumer_output *consumer,
 261                 struct consumer_socket *socket,
 262                 struct ust_registry_session *registry,
 263                 struct lttng_trace_chunk * trace_chunk)
 264 {
 265         int ret;
 266
 267         assert(ua_sess);
 268         assert(ua_chan);
 269         assert(consumer);
 270         assert(socket);
 271         assert(registry);
 272
 273         if (!consumer->enabled) {
 274                 ret = -LTTNG_ERR_NO_CONSUMER;
 275                 DBG3("Consumer is disabled");
 276                 goto error;
 277         }
 278
 279         pthread_mutex_lock(socket->lock);
 280         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry,
 281                         trace_chunk);
 282         pthread_mutex_unlock(socket->lock);
 283         if (ret < 0) {
 284                 ERR("ask_channel_creation consumer command failed");
 285                 goto error;
 286         }
 287
 288 error:
 289         return ret;
 290 }
 291
 292 /*
 293  * Send a get channel command to consumer using the given channel key.  The
 294  * channel object is populated and the stream list.
 295  *
 296  * Return 0 on success else a negative value.
 297  */
 298 int ust_consumer_get_channel(struct consumer_socket *socket,
 299                 struct ust_app_channel *ua_chan)
 300 {
 301         int ret;
 302         struct lttcomm_consumer_msg msg;
 303
 304         assert(ua_chan);
 305         assert(socket);
 306
 307         memset(&msg, 0, sizeof(msg));
 308         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 309         msg.u.get_channel.key = ua_chan->key;
 310
 311         pthread_mutex_lock(socket->lock);
 312         health_code_update();
 313
 314         /* Send command and wait for OK reply. */
 315         ret = consumer_send_msg(socket, &msg);
 316         if (ret < 0) {
 317                 goto error;
 318         }
 319
 320         /* First, get the channel from consumer. */
 321         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 322         if (ret < 0) {
 323                 if (ret != -EPIPE) {
 324                         ERR("Error recv channel from consumer %d with ret %d",
 325                                         *socket->fd_ptr, ret);
 326                 } else {
 327                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 328                 }
 329                 goto error;
 330         }
 331
 332         /* Next, get all streams. */
 333         while (1) {
 334                 struct ust_app_stream *stream;
 335
 336                 /* Create UST stream */
 337                 stream = ust_app_alloc_stream();
 338                 if (stream == NULL) {
 339                         ret = -ENOMEM;
 340                         goto error;
 341                 }
 342
 343                 /* Stream object is populated by this call if successful. */
 344                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 345                 if (ret < 0) {
 346                         free(stream);
 347                         if (ret == -LTTNG_UST_ERR_NOENT) {
 348                                 DBG3("UST app consumer has no more stream available");
 349                                 break;
 350                         }
 351                         if (ret != -EPIPE) {
 352                                 ERR("Recv stream from consumer %d with ret %d",
 353                                                 *socket->fd_ptr, ret);
 354                         } else {
 355                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 356                         }
 357                         goto error;
 358                 }
 359
 360                 /* Order is important this is why a list is used. */
 361                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 362                 ua_chan->streams.count++;
 363
 364                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 365         }
 366
 367         /* This MUST match or else we have a synchronization problem. */
 368         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 369
 370         /* Wait for confirmation that we can proceed with the streams. */
 371         ret = consumer_recv_status_reply(socket);
 372         if (ret < 0) {
 373                 goto error;
 374         }
 375
 376 error:
 377         health_code_update();
 378         pthread_mutex_unlock(socket->lock);
 379         return ret;
 380 }
 381
 382 /*
 383  * Send a destroy channel command to consumer using the given channel key.
 384  *
 385  * Note that this command MUST be used prior to a successful
 386  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 387  * the streams are dispatched to the consumer threads and MUST be teardown
 388  * through the hang up process.
 389  *
 390  * Return 0 on success else a negative value.
 391  */
 392 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 393                 struct ust_app_channel *ua_chan)
 394 {
 395         int ret;
 396         struct lttcomm_consumer_msg msg;
 397
 398         assert(ua_chan);
 399         assert(socket);
 400
 401         memset(&msg, 0, sizeof(msg));
 402         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 403         msg.u.destroy_channel.key = ua_chan->key;
 404
 405         pthread_mutex_lock(socket->lock);
 406         health_code_update();
 407
 408         ret = consumer_send_msg(socket, &msg);
 409         if (ret < 0) {
 410                 goto error;
 411         }
 412
 413 error:
 414         health_code_update();
 415         pthread_mutex_unlock(socket->lock);
 416         return ret;
 417 }
 418
 419 /*
 420  * Send a given stream to UST tracer.
 421  *
 422  * On success return 0 else a negative value.
 423  */
 424 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 425                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 426 {
 427         int ret;
 428
 429         assert(app);
 430         assert(stream);
 431         assert(channel);
 432
 433         DBG2("UST consumer send stream to app %d", app->sock);
 434
 435         /* Relay stream to application. */
 436         pthread_mutex_lock(&app->sock_lock);
 437         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 438         pthread_mutex_unlock(&app->sock_lock);
 439         if (ret < 0) {
 440                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 441                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 442                                         stream->obj->handle, app->pid, ret);
 443                 } else {
 444                         DBG3("UST app send stream to ust failed. Application is dead.");
 445                 }
 446                 goto error;
 447         }
 448         channel->handle = channel->obj->handle;
 449
 450 error:
 451         return ret;
 452 }
 453
 454 /*
 455  * Send channel previously received from the consumer to the UST tracer.
 456  *
 457  * On success return 0 else a negative value.
 458  */
 459 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 460                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 461 {
 462         int ret;
 463
 464         assert(app);
 465         assert(ua_sess);
 466         assert(channel);
 467         assert(channel->obj);
 468
 469         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 470                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 471
 472         /* Send stream to application. */
 473         pthread_mutex_lock(&app->sock_lock);
 474         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 475         pthread_mutex_unlock(&app->sock_lock);
 476         if (ret < 0) {
 477                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 478                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 479                                         channel->name, app->pid, ret);
 480                 } else {
 481                         DBG3("UST app send channel to ust failed. Application is dead.");
 482                 }
 483                 goto error;
 484         }
 485
 486 error:
 487         return ret;
 488 }
 489
 490 /*
 491  * Handle the metadata requests from the UST consumer
 492  *
 493  * Return 0 on success else a negative value.
 494  */
 495 int ust_consumer_metadata_request(struct consumer_socket *socket)
 496 {
 497         int ret;
 498         ssize_t ret_push;
 499         struct lttcomm_metadata_request_msg request;
 500         struct buffer_reg_uid *reg_uid;
 501         struct ust_registry_session *ust_reg;
 502         struct lttcomm_consumer_msg msg;
 503
 504         assert(socket);
 505
 506         rcu_read_lock();
 507         health_code_update();
 508
 509         /* Wait for a metadata request */
 510         pthread_mutex_lock(socket->lock);
 511         ret = consumer_socket_recv(socket, &request, sizeof(request));
 512         pthread_mutex_unlock(socket->lock);
 513         if (ret < 0) {
 514                 goto end;
 515         }
 516
 517         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 518                         request.session_id, request.key);
 519
 520         reg_uid = buffer_reg_uid_find(request.session_id,
 521                         request.bits_per_long, request.uid);
 522         if (reg_uid) {
 523                 ust_reg = reg_uid->registry->reg.ust;
 524         } else {
 525                 struct buffer_reg_pid *reg_pid =
 526                         buffer_reg_pid_find(request.session_id_per_pid);
 527                 if (!reg_pid) {
 528                         DBG("PID registry not found for session id %" PRIu64,
 529                                         request.session_id_per_pid);
 530
 531                         memset(&msg, 0, sizeof(msg));
 532                         msg.cmd_type = LTTNG_ERR_UND;
 533                         pthread_mutex_lock(socket->lock);
 534                         (void) consumer_send_msg(socket, &msg);
 535                         pthread_mutex_unlock(socket->lock);
 536                         /*
 537                          * This is possible since the session might have been destroyed
 538                          * during a consumer metadata request. So here, return gracefully
 539                          * because the destroy session will push the remaining metadata to
 540                          * the consumer.
 541                          */
 542                         ret = 0;
 543                         goto end;
 544                 }
 545                 ust_reg = reg_pid->registry->reg.ust;
 546         }
 547         assert(ust_reg);
 548
 549         pthread_mutex_lock(&ust_reg->lock);
 550         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 551         pthread_mutex_unlock(&ust_reg->lock);
 552         if (ret_push == -EPIPE) {
 553                 DBG("Application or relay closed while pushing metadata");
 554         } else if (ret_push < 0) {
 555                 ERR("Pushing metadata");
 556                 ret = -1;
 557                 goto end;
 558         } else {
 559                 DBG("UST Consumer metadata pushed successfully");
 560         }
 561         ret = 0;
 562
 563 end:
 564         rcu_read_unlock();
 565         return ret;
 566 }