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 "lttng-ust-error.h"
  34 #include "buffer-registry.h"
  35 #include "session.h"
  36 #include "lttng-sessiond.h"
  37
  38 /*
  39  * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
  40  *
  41  * Consumer socket lock MUST be acquired before calling this.
  42  */
  43 static int ask_channel_creation(struct ust_app_session *ua_sess,
  44                 struct ust_app_channel *ua_chan,
  45                 struct consumer_output *consumer,
  46                 struct consumer_socket *socket,
  47                 struct ust_registry_session *registry,
  48                 struct lttng_trace_chunk *trace_chunk)
  49 {
  50         int ret, output;
  51         uint32_t chan_id;
  52         uint64_t key, chan_reg_key;
  53         char *pathname = NULL;
  54         struct lttcomm_consumer_msg msg;
  55         struct ust_registry_channel *chan_reg;
  56         char shm_path[PATH_MAX] = "";
  57         char root_shm_path[PATH_MAX] = "";
  58         bool is_local_trace;
  59         size_t consumer_path_offset = 0;
  60
  61         assert(ua_sess);
  62         assert(ua_chan);
  63         assert(socket);
  64         assert(consumer);
  65         assert(registry);
  66
  67         DBG2("Asking UST consumer for channel");
  68
  69         is_local_trace = consumer->net_seq_index == -1ULL;
  70         /* Format the channel's path (relative to the current trace chunk). */
  71         pathname = setup_channel_trace_path(consumer, ua_sess->path,
  72                         &consumer_path_offset);
  73         if (!pathname) {
  74                 ret = -1;
  75                 goto error;
  76         }
  77
  78         if (is_local_trace && trace_chunk) {
  79                 enum lttng_trace_chunk_status chunk_status;
  80                 char *pathname_index;
  81
  82                 ret = asprintf(&pathname_index, "%s/" DEFAULT_INDEX_DIR,
  83                                 pathname);
  84                 if (ret < 0) {
  85                         ERR("Failed to format channel index directory");
  86                         ret = -1;
  87                         goto error;
  88                 }
  89
  90                 /*
  91                  * Create the index subdirectory which will take care
  92                  * of implicitly creating the channel's path.
  93                  */
  94                 chunk_status = lttng_trace_chunk_create_subdirectory(
  95                                 trace_chunk, pathname_index);
  96                 free(pathname_index);
  97                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  98                         ret = -1;
  99                         goto error;
 100                 }
 101         }
 102
 103         /* Depending on the buffer type, a different channel key is used. */
 104         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 105                 chan_reg_key = ua_chan->tracing_channel_id;
 106         } else {
 107                 chan_reg_key = ua_chan->key;
 108         }
 109
 110         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 111                 chan_id = -1U;
 112                 /*
 113                  * Metadata channels shm_path (buffers) are handled within
 114                  * session daemon. Consumer daemon should not try to create
 115                  * those buffer files.
 116                  */
 117         } else {
 118                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 119                 assert(chan_reg);
 120                 chan_id = chan_reg->chan_id;
 121                 if (ua_sess->shm_path[0]) {
 122                         strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
 123                         shm_path[sizeof(shm_path) - 1] = '\0';
 124                         strncat(shm_path, "/",
 125                                 sizeof(shm_path) - strlen(shm_path) - 1);
 126                         strncat(shm_path, ua_chan->name,
 127                                         sizeof(shm_path) - strlen(shm_path) - 1);
 128                                 strncat(shm_path, "_",
 129                                         sizeof(shm_path) - strlen(shm_path) - 1);
 130                 }
 131                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 132                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 133         }
 134
 135         switch (ua_chan->attr.output) {
 136         case LTTNG_UST_MMAP:
 137         default:
 138                 output = LTTNG_EVENT_MMAP;
 139                 break;
 140         }
 141
 142         consumer_init_ask_channel_comm_msg(&msg,
 143                         ua_chan->attr.subbuf_size,
 144                         ua_chan->attr.num_subbuf,
 145                         ua_chan->attr.overwrite,
 146                         ua_chan->attr.switch_timer_interval,
 147                         ua_chan->attr.read_timer_interval,
 148                         ua_sess->live_timer_interval,
 149                         ua_chan->monitor_timer_interval,
 150                         output,
 151                         (int) ua_chan->attr.type,
 152                         ua_sess->tracing_id,
 153                         &pathname[consumer_path_offset],
 154                         ua_chan->name,
 155                         consumer->net_seq_index,
 156                         ua_chan->key,
 157                         registry->uuid,
 158                         chan_id,
 159                         ua_chan->tracefile_size,
 160                         ua_chan->tracefile_count,
 161                         ua_sess->id,
 162                         ua_sess->output_traces,
 163                         ua_sess->real_credentials.uid,
 164                         ua_chan->attr.blocking_timeout,
 165                         root_shm_path, shm_path,
 166                         trace_chunk,
 167                         &ua_sess->effective_credentials);
 168
 169         health_code_update();
 170
 171         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 172         if (ret < 0) {
 173                 goto error;
 174         }
 175
 176         ret = consumer_recv_status_channel(socket, &key,
 177                         &ua_chan->expected_stream_count);
 178         if (ret < 0) {
 179                 goto error;
 180         }
 181         /* Communication protocol error. */
 182         assert(key == ua_chan->key);
 183         /* We need at least one where 1 stream for 1 cpu. */
 184         if (ua_sess->output_traces) {
 185                 assert(ua_chan->expected_stream_count > 0);
 186         }
 187
 188         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 189                         ua_chan->expected_stream_count);
 190
 191 error:
 192         free(pathname);
 193         health_code_update();
 194         return ret;
 195 }
 196
 197 /*
 198  * Ask consumer to create a channel for a given session.
 199  *
 200  * Session list and rcu read side locks must be held by the caller.
 201  *
 202  * Returns 0 on success else a negative value.
 203  */
 204 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 205                 struct ust_app_channel *ua_chan,
 206                 struct consumer_output *consumer,
 207                 struct consumer_socket *socket,
 208                 struct ust_registry_session *registry,
 209                 struct lttng_trace_chunk * trace_chunk)
 210 {
 211         int ret;
 212
 213         assert(ua_sess);
 214         assert(ua_chan);
 215         assert(consumer);
 216         assert(socket);
 217         assert(registry);
 218
 219         if (!consumer->enabled) {
 220                 ret = -LTTNG_ERR_NO_CONSUMER;
 221                 DBG3("Consumer is disabled");
 222                 goto error;
 223         }
 224
 225         pthread_mutex_lock(socket->lock);
 226         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry,
 227                         trace_chunk);
 228         pthread_mutex_unlock(socket->lock);
 229         if (ret < 0) {
 230                 ERR("ask_channel_creation consumer command failed");
 231                 goto error;
 232         }
 233
 234 error:
 235         return ret;
 236 }
 237
 238 /*
 239  * Send a get channel command to consumer using the given channel key.  The
 240  * channel object is populated and the stream list.
 241  *
 242  * Return 0 on success else a negative value.
 243  */
 244 int ust_consumer_get_channel(struct consumer_socket *socket,
 245                 struct ust_app_channel *ua_chan)
 246 {
 247         int ret;
 248         struct lttcomm_consumer_msg msg;
 249
 250         assert(ua_chan);
 251         assert(socket);
 252
 253         memset(&msg, 0, sizeof(msg));
 254         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 255         msg.u.get_channel.key = ua_chan->key;
 256
 257         pthread_mutex_lock(socket->lock);
 258         health_code_update();
 259
 260         /* Send command and wait for OK reply. */
 261         ret = consumer_send_msg(socket, &msg);
 262         if (ret < 0) {
 263                 goto error;
 264         }
 265
 266         /* First, get the channel from consumer. */
 267         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 268         if (ret < 0) {
 269                 if (ret != -EPIPE) {
 270                         ERR("Error recv channel from consumer %d with ret %d",
 271                                         *socket->fd_ptr, ret);
 272                 } else {
 273                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 274                 }
 275                 goto error;
 276         }
 277
 278         /* Next, get all streams. */
 279         while (1) {
 280                 struct ust_app_stream *stream;
 281
 282                 /* Create UST stream */
 283                 stream = ust_app_alloc_stream();
 284                 if (stream == NULL) {
 285                         ret = -ENOMEM;
 286                         goto error;
 287                 }
 288
 289                 /* Stream object is populated by this call if successful. */
 290                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 291                 if (ret < 0) {
 292                         free(stream);
 293                         if (ret == -LTTNG_UST_ERR_NOENT) {
 294                                 DBG3("UST app consumer has no more stream available");
 295                                 break;
 296                         }
 297                         if (ret != -EPIPE) {
 298                                 ERR("Recv stream from consumer %d with ret %d",
 299                                                 *socket->fd_ptr, ret);
 300                         } else {
 301                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 302                         }
 303                         goto error;
 304                 }
 305
 306                 /* Order is important this is why a list is used. */
 307                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 308                 ua_chan->streams.count++;
 309
 310                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 311         }
 312
 313         /* This MUST match or else we have a synchronization problem. */
 314         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 315
 316         /* Wait for confirmation that we can proceed with the streams. */
 317         ret = consumer_recv_status_reply(socket);
 318         if (ret < 0) {
 319                 goto error;
 320         }
 321
 322 error:
 323         health_code_update();
 324         pthread_mutex_unlock(socket->lock);
 325         return ret;
 326 }
 327
 328 /*
 329  * Send a destroy channel command to consumer using the given channel key.
 330  *
 331  * Note that this command MUST be used prior to a successful
 332  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 333  * the streams are dispatched to the consumer threads and MUST be teardown
 334  * through the hang up process.
 335  *
 336  * Return 0 on success else a negative value.
 337  */
 338 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 339                 struct ust_app_channel *ua_chan)
 340 {
 341         int ret;
 342         struct lttcomm_consumer_msg msg;
 343
 344         assert(ua_chan);
 345         assert(socket);
 346
 347         memset(&msg, 0, sizeof(msg));
 348         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 349         msg.u.destroy_channel.key = ua_chan->key;
 350
 351         pthread_mutex_lock(socket->lock);
 352         health_code_update();
 353
 354         ret = consumer_send_msg(socket, &msg);
 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 given stream to UST tracer.
 367  *
 368  * On success return 0 else a negative value.
 369  */
 370 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 371                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 372 {
 373         int ret;
 374
 375         assert(app);
 376         assert(stream);
 377         assert(channel);
 378
 379         DBG2("UST consumer send stream to app %d", app->sock);
 380
 381         /* Relay stream to application. */
 382         pthread_mutex_lock(&app->sock_lock);
 383         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 384         pthread_mutex_unlock(&app->sock_lock);
 385         if (ret < 0) {
 386                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 387                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 388                                         stream->obj->handle, app->pid, ret);
 389                 } else {
 390                         DBG3("UST app send stream to ust failed. Application is dead.");
 391                 }
 392                 goto error;
 393         }
 394         channel->handle = channel->obj->handle;
 395
 396 error:
 397         return ret;
 398 }
 399
 400 /*
 401  * Send channel previously received from the consumer to the UST tracer.
 402  *
 403  * On success return 0 else a negative value.
 404  */
 405 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 406                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 407 {
 408         int ret;
 409
 410         assert(app);
 411         assert(ua_sess);
 412         assert(channel);
 413         assert(channel->obj);
 414
 415         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 416                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 417
 418         /* Send stream to application. */
 419         pthread_mutex_lock(&app->sock_lock);
 420         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 421         pthread_mutex_unlock(&app->sock_lock);
 422         if (ret < 0) {
 423                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 424                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 425                                         channel->name, app->pid, ret);
 426                 } else {
 427                         DBG3("UST app send channel to ust failed. Application is dead.");
 428                 }
 429                 goto error;
 430         }
 431
 432 error:
 433         return ret;
 434 }
 435
 436 /*
 437  * Handle the metadata requests from the UST consumer
 438  *
 439  * Return 0 on success else a negative value.
 440  */
 441 int ust_consumer_metadata_request(struct consumer_socket *socket)
 442 {
 443         int ret;
 444         ssize_t ret_push;
 445         struct lttcomm_metadata_request_msg request;
 446         struct buffer_reg_uid *reg_uid;
 447         struct ust_registry_session *ust_reg;
 448         struct lttcomm_consumer_msg msg;
 449
 450         assert(socket);
 451
 452         rcu_read_lock();
 453         health_code_update();
 454
 455         /* Wait for a metadata request */
 456         pthread_mutex_lock(socket->lock);
 457         ret = consumer_socket_recv(socket, &request, sizeof(request));
 458         pthread_mutex_unlock(socket->lock);
 459         if (ret < 0) {
 460                 goto end;
 461         }
 462
 463         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 464                         request.session_id, request.key);
 465
 466         reg_uid = buffer_reg_uid_find(request.session_id,
 467                         request.bits_per_long, request.uid);
 468         if (reg_uid) {
 469                 ust_reg = reg_uid->registry->reg.ust;
 470         } else {
 471                 struct buffer_reg_pid *reg_pid =
 472                         buffer_reg_pid_find(request.session_id_per_pid);
 473                 if (!reg_pid) {
 474                         DBG("PID registry not found for session id %" PRIu64,
 475                                         request.session_id_per_pid);
 476
 477                         memset(&msg, 0, sizeof(msg));
 478                         msg.cmd_type = LTTNG_ERR_UND;
 479                         pthread_mutex_lock(socket->lock);
 480                         (void) consumer_send_msg(socket, &msg);
 481                         pthread_mutex_unlock(socket->lock);
 482                         /*
 483                          * This is possible since the session might have been destroyed
 484                          * during a consumer metadata request. So here, return gracefully
 485                          * because the destroy session will push the remaining metadata to
 486                          * the consumer.
 487                          */
 488                         ret = 0;
 489                         goto end;
 490                 }
 491                 ust_reg = reg_pid->registry->reg.ust;
 492         }
 493         assert(ust_reg);
 494
 495         pthread_mutex_lock(&ust_reg->lock);
 496         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 497         pthread_mutex_unlock(&ust_reg->lock);
 498         if (ret_push == -EPIPE) {
 499                 DBG("Application or relay closed while pushing metadata");
 500         } else if (ret_push < 0) {
 501                 ERR("Pushing metadata");
 502                 ret = -1;
 503                 goto end;
 504         } else {
 505                 DBG("UST Consumer metadata pushed successfully");
 506         }
 507         ret = 0;
 508
 509 end:
 510         rcu_read_unlock();
 511         return ret;
 512 }