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