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",
  66                                 consumer->dst.trace_path, consumer->subdir, ua_sess->path);
  67                 if (ret < 0) {
  68                         PERROR("snprintf channel path");
  69                         goto error;
  70                 }
  71
  72                 /* Create directory. Ignore if exist. */
  73                 ret = run_as_mkdir_recursive(pathname, S_IRWXU | S_IRWXG,
  74                                 ua_sess->euid, ua_sess->egid);
  75                 if (ret < 0) {
  76                         if (errno != EEXIST) {
  77                                 ERR("Trace directory creation error");
  78                                 goto error;
  79                         }
  80                 }
  81         } else {
  82                 ret = snprintf(pathname, PATH_MAX, "%s%s", consumer->subdir,
  83                                 ua_sess->path);
  84                 if (ret < 0) {
  85                         PERROR("snprintf channel path");
  86                         goto error;
  87                 }
  88         }
  89
  90         return pathname;
  91
  92 error:
  93         free(pathname);
  94         return NULL;
  95 }
  96
  97 /*
  98  * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
  99  *
 100  * Consumer socket lock MUST be acquired before calling this.
 101  */
 102 static int ask_channel_creation(struct ust_app_session *ua_sess,
 103                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 104                 struct consumer_socket *socket, struct ust_registry_session *registry)
 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
 115         assert(ua_sess);
 116         assert(ua_chan);
 117         assert(socket);
 118         assert(consumer);
 119         assert(registry);
 120
 121         DBG2("Asking UST consumer for channel");
 122
 123         /* Get and create full trace path of session. */
 124         if (ua_sess->output_traces) {
 125                 pathname = setup_trace_path(consumer, ua_sess);
 126                 if (!pathname) {
 127                         ret = -1;
 128                         goto error;
 129                 }
 130         }
 131
 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;
 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                  */
 146         } else {
 147                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 148                 assert(chan_reg);
 149                 chan_id = chan_reg->chan_id;
 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                 }
 160                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 161                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 162         }
 163
 164         switch (ua_chan->attr.output) {
 165         case LTTNG_UST_MMAP:
 166         default:
 167                 output = LTTNG_EVENT_MMAP;
 168                 break;
 169         }
 170
 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,
 177                         ua_sess->live_timer_interval,
 178                         ua_chan->monitor_timer_interval,
 179                         output,
 180                         (int) ua_chan->attr.type,
 181                         ua_sess->tracing_id,
 182                         pathname,
 183                         ua_chan->name,
 184                         ua_sess->euid,
 185                         ua_sess->egid,
 186                         consumer->net_seq_index,
 187                         ua_chan->key,
 188                         registry->uuid,
 189                         chan_id,
 190                         ua_chan->tracefile_size,
 191                         ua_chan->tracefile_count,
 192                         ua_sess->id,
 193                         ua_sess->output_traces,
 194                         ua_sess->uid,
 195                         root_shm_path, shm_path);
 196
 197         health_code_update();
 198
 199         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 200         if (ret < 0) {
 201                 goto error;
 202         }
 203
 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. */
 212         if (ua_sess->output_traces) {
 213                 assert(ua_chan->expected_stream_count > 0);
 214         }
 215
 216         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 217                         ua_chan->expected_stream_count);
 218
 219 error:
 220         free(pathname);
 221         health_code_update();
 222         return ret;
 223 }
 224
 225 /*
 226  * Ask consumer to create a channel for a given session.
 227  *
 228  * Session list and rcu read side locks must be held by the caller.
 229  *
 230  * Returns 0 on success else a negative value.
 231  */
 232 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 233                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 234                 struct consumer_socket *socket, struct ust_registry_session *registry)
 235 {
 236         int ret;
 237         struct ltt_session *session;
 238
 239         assert(ua_sess);
 240         assert(ua_chan);
 241         assert(consumer);
 242         assert(socket);
 243         assert(registry);
 244
 245         if (!consumer->enabled) {
 246                 ret = -LTTNG_ERR_NO_CONSUMER;
 247                 DBG3("Consumer is disabled");
 248                 goto error;
 249         }
 250
 251         session = session_find_by_id(ua_sess->tracing_id);
 252         assert(session);
 253
 254         pthread_mutex_lock(socket->lock);
 255         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 256         pthread_mutex_unlock(socket->lock);
 257         if (ret < 0) {
 258                 ERR("ask_channel_creation consumer command failed");
 259                 goto error;
 260         }
 261
 262 error:
 263         return ret;
 264 }
 265
 266 /*
 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.
 271  */
 272 int ust_consumer_get_channel(struct consumer_socket *socket,
 273                 struct ust_app_channel *ua_chan)
 274 {
 275         int ret;
 276         struct lttcomm_consumer_msg msg;
 277
 278         assert(ua_chan);
 279         assert(socket);
 280
 281         memset(&msg, 0, sizeof(msg));
 282         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 283         msg.u.get_channel.key = ua_chan->key;
 284
 285         pthread_mutex_lock(socket->lock);
 286         health_code_update();
 287
 288         /* Send command and wait for OK reply. */
 289         ret = consumer_send_msg(socket, &msg);
 290         if (ret < 0) {
 291                 goto error;
 292         }
 293
 294         /* First, get the channel from consumer. */
 295         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 296         if (ret < 0) {
 297                 if (ret != -EPIPE) {
 298                         ERR("Error recv channel from consumer %d with ret %d",
 299                                         *socket->fd_ptr, ret);
 300                 } else {
 301                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 302                 }
 303                 goto error;
 304         }
 305
 306         /* Next, get all streams. */
 307         while (1) {
 308                 struct ust_app_stream *stream;
 309
 310                 /* Create UST stream */
 311                 stream = ust_app_alloc_stream();
 312                 if (stream == NULL) {
 313                         ret = -ENOMEM;
 314                         goto error;
 315                 }
 316
 317                 /* Stream object is populated by this call if successful. */
 318                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 319                 if (ret < 0) {
 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",
 328                                                 *socket->fd_ptr, ret);
 329                         } else {
 330                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 331                         }
 332                         goto error;
 333                 }
 334
 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++;
 338
 339                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 340         }
 341
 342         /* This MUST match or else we have a synchronization problem. */
 343         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 344
 345         /* Wait for confirmation that we can proceed with the streams. */
 346         ret = consumer_recv_status_reply(socket);
 347         if (ret < 0) {
 348                 goto error;
 349         }
 350
 351 error:
 352         health_code_update();
 353         pthread_mutex_unlock(socket->lock);
 354         return ret;
 355 }
 356
 357 /*
 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.
 366  */
 367 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 368                 struct ust_app_channel *ua_chan)
 369 {
 370         int ret;
 371         struct lttcomm_consumer_msg msg;
 372
 373         assert(ua_chan);
 374         assert(socket);
 375
 376         memset(&msg, 0, sizeof(msg));
 377         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 378         msg.u.destroy_channel.key = ua_chan->key;
 379
 380         pthread_mutex_lock(socket->lock);
 381         health_code_update();
 382
 383         ret = consumer_send_msg(socket, &msg);
 384         if (ret < 0) {
 385                 goto error;
 386         }
 387
 388 error:
 389         health_code_update();
 390         pthread_mutex_unlock(socket->lock);
 391         return ret;
 392 }
 393
 394 /*
 395  * Send a given stream to UST tracer.
 396  *
 397  * On success return 0 else a negative value.
 398  */
 399 int 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. */
 411         pthread_mutex_lock(&app->sock_lock);
 412         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 413         pthread_mutex_unlock(&app->sock_lock);
 414         if (ret < 0) {
 415                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 416                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 417                                         stream->obj->handle, app->pid, ret);
 418                 } else {
 419                         DBG3("UST app send stream to ust failed. Application is dead.");
 420                 }
 421                 goto error;
 422         }
 423         channel->handle = channel->obj->handle;
 424
 425 error:
 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  */
 434 int 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
 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);
 446
 447         /* Send stream to application. */
 448         pthread_mutex_lock(&app->sock_lock);
 449         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 450         pthread_mutex_unlock(&app->sock_lock);
 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         }
 460
 461 error:
 462         return ret;
 463 }
 464
 465 /*
 466  * Handle the metadata requests from the UST consumer
 467  *
 468  * Return 0 on success else a negative value.
 469  */
 470 int 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();
 482         health_code_update();
 483
 484         /* Wait for a metadata request */
 485         pthread_mutex_lock(socket->lock);
 486         ret = consumer_socket_recv(socket, &request, sizeof(request));
 487         pthread_mutex_unlock(socket->lock);
 488         if (ret < 0) {
 489                 goto end;
 490         }
 491
 492         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 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 =
 501                         buffer_reg_pid_find(request.session_id_per_pid);
 502                 if (!reg_pid) {
 503                         DBG("PID registry not found for session id %" PRIu64,
 504                                         request.session_id_per_pid);
 505
 506                         memset(&msg, 0, sizeof(msg));
 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
 522         pthread_mutex_lock(&ust_reg->lock);
 523         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 524         pthread_mutex_unlock(&ust_reg->lock);
 525         if (ret_push == -EPIPE) {
 526                 DBG("Application or relay closed while pushing metadata");
 527         } else if (ret_push < 0) {
 528                 ERR("Pushing metadata");
 529                 ret = -1;
 530                 goto end;
 531         } else {
 532                 DBG("UST Consumer metadata pushed successfully");
 533         }
 534         ret = 0;
 535
 536 end:
 537         rcu_read_unlock();
 538         return ret;
 539 }