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

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <inttypes.h>
  14
  15 #include <common/compat/errno.hpp>
  16 #include <common/common.hpp>
  17 #include <common/consumer/consumer.hpp>
  18 #include <common/defaults.hpp>
  19
  20 #include "consumer.hpp"
  21 #include "health-sessiond.hpp"
  22 #include "ust-consumer.hpp"
  23 #include "lttng-ust-error.hpp"
  24 #include "buffer-registry.hpp"
  25 #include "session.hpp"
  26 #include "lttng-sessiond.hpp"
  27
  28 namespace lsu = lttng::sessiond::ust;
  29
  30 /*
  31  * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
  32  *
  33  * Consumer socket lock MUST be acquired before calling this.
  34  */
  35 static int ask_channel_creation(struct ust_app_session *ua_sess,
  36                 struct ust_app_channel *ua_chan,
  37                 struct consumer_output *consumer,
  38                 struct consumer_socket *socket,
  39                 lsu::registry_session *registry,
  40                 struct lttng_trace_chunk *trace_chunk)
  41 {
  42         int ret, output;
  43         uint32_t chan_id;
  44         uint64_t key, chan_reg_key;
  45         char *pathname = NULL;
  46         struct lttcomm_consumer_msg msg;
  47         char shm_path[PATH_MAX] = "";
  48         char root_shm_path[PATH_MAX] = "";
  49         bool is_local_trace;
  50         size_t consumer_path_offset = 0;
  51
  52         LTTNG_ASSERT(ua_sess);
  53         LTTNG_ASSERT(ua_chan);
  54         LTTNG_ASSERT(socket);
  55         LTTNG_ASSERT(consumer);
  56         LTTNG_ASSERT(registry);
  57
  58         DBG2("Asking UST consumer for channel");
  59
  60         is_local_trace = consumer->net_seq_index == -1ULL;
  61         /* Format the channel's path (relative to the current trace chunk). */
  62         pathname = setup_channel_trace_path(consumer, ua_sess->path,
  63                         &consumer_path_offset);
  64         if (!pathname) {
  65                 ret = -1;
  66                 goto error;
  67         }
  68
  69         if (is_local_trace && trace_chunk) {
  70                 enum lttng_trace_chunk_status chunk_status;
  71                 char *pathname_index;
  72
  73                 ret = asprintf(&pathname_index, "%s/" DEFAULT_INDEX_DIR,
  74                                 pathname);
  75                 if (ret < 0) {
  76                         ERR("Failed to format channel index directory");
  77                         ret = -1;
  78                         goto error;
  79                 }
  80
  81                 /*
  82                  * Create the index subdirectory which will take care
  83                  * of implicitly creating the channel's path.
  84                  */
  85                 chunk_status = lttng_trace_chunk_create_subdirectory(
  86                                 trace_chunk, pathname_index);
  87                 free(pathname_index);
  88                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  89                         ret = -1;
  90                         goto error;
  91                 }
  92         }
  93
  94         /* Depending on the buffer type, a different channel key is used. */
  95         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
  96                 chan_reg_key = ua_chan->tracing_channel_id;
  97         } else {
  98                 chan_reg_key = ua_chan->key;
  99         }
 100
 101         if (ua_chan->attr.type == LTTNG_UST_ABI_CHAN_METADATA) {
 102                 chan_id = -1U;
 103                 /*
 104                  * Metadata channels shm_path (buffers) are handled within
 105                  * session daemon. Consumer daemon should not try to create
 106                  * those buffer files.
 107                  */
 108         } else {
 109                 {
 110                         auto locked_registry = registry->lock();
 111                         auto& ust_reg_chan = registry->get_channel(chan_reg_key);
 112
 113                         chan_id = ust_reg_chan.id;
 114                 }
 115
 116                 if (ua_sess->shm_path[0]) {
 117                         strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
 118                         shm_path[sizeof(shm_path) - 1] = '\0';
 119                         strncat(shm_path, "/",
 120                                 sizeof(shm_path) - strlen(shm_path) - 1);
 121                         strncat(shm_path, ua_chan->name,
 122                                         sizeof(shm_path) - strlen(shm_path) - 1);
 123                                 strncat(shm_path, "_",
 124                                         sizeof(shm_path) - strlen(shm_path) - 1);
 125                 }
 126                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 127                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 128         }
 129
 130         switch (ua_chan->attr.output) {
 131         case LTTNG_UST_ABI_MMAP:
 132         default:
 133                 output = LTTNG_EVENT_MMAP;
 134                 break;
 135         }
 136
 137         consumer_init_ask_channel_comm_msg(&msg,
 138                         ua_chan->attr.subbuf_size,
 139                         ua_chan->attr.num_subbuf,
 140                         ua_chan->attr.overwrite,
 141                         ua_chan->attr.switch_timer_interval,
 142                         ua_chan->attr.read_timer_interval,
 143                         ua_sess->live_timer_interval,
 144                         ua_sess->live_timer_interval != 0,
 145                         ua_chan->monitor_timer_interval,
 146                         output,
 147                         (int) ua_chan->attr.type,
 148                         ua_sess->tracing_id,
 149                         &pathname[consumer_path_offset],
 150                         ua_chan->name,
 151                         consumer->net_seq_index,
 152                         ua_chan->key,
 153                         registry->uuid,
 154                         chan_id,
 155                         ua_chan->tracefile_size,
 156                         ua_chan->tracefile_count,
 157                         ua_sess->id,
 158                         ua_sess->output_traces,
 159                         lttng_credentials_get_uid(&ua_sess->real_credentials),
 160                         ua_chan->attr.blocking_timeout,
 161                         root_shm_path, shm_path,
 162                         trace_chunk,
 163                         &ua_sess->effective_credentials);
 164
 165         health_code_update();
 166
 167         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 168         if (ret < 0) {
 169                 goto error;
 170         }
 171
 172         ret = consumer_recv_status_channel(socket, &key,
 173                         &ua_chan->expected_stream_count);
 174         if (ret < 0) {
 175                 goto error;
 176         }
 177         /* Communication protocol error. */
 178         LTTNG_ASSERT(key == ua_chan->key);
 179         /* We need at least one where 1 stream for 1 cpu. */
 180         if (ua_sess->output_traces) {
 181                 LTTNG_ASSERT(ua_chan->expected_stream_count > 0);
 182         }
 183
 184         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 185                         ua_chan->expected_stream_count);
 186
 187 error:
 188         free(pathname);
 189         health_code_update();
 190         return ret;
 191 }
 192
 193 /*
 194  * Ask consumer to create a channel for a given session.
 195  *
 196  * Session list and rcu read side locks must be held by the caller.
 197  *
 198  * Returns 0 on success else a negative value.
 199  */
 200 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 201                 struct ust_app_channel *ua_chan,
 202                 struct consumer_output *consumer,
 203                 struct consumer_socket *socket,
 204                 lsu::registry_session *registry,
 205                 struct lttng_trace_chunk * trace_chunk)
 206 {
 207         int ret;
 208
 209         LTTNG_ASSERT(ua_sess);
 210         LTTNG_ASSERT(ua_chan);
 211         LTTNG_ASSERT(consumer);
 212         LTTNG_ASSERT(socket);
 213         LTTNG_ASSERT(registry);
 214
 215         if (!consumer->enabled) {
 216                 ret = -LTTNG_ERR_NO_CONSUMER;
 217                 DBG3("Consumer is disabled");
 218                 goto error;
 219         }
 220
 221         pthread_mutex_lock(socket->lock);
 222         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry,
 223                         trace_chunk);
 224         pthread_mutex_unlock(socket->lock);
 225         if (ret < 0) {
 226                 ERR("ask_channel_creation consumer command failed");
 227                 goto error;
 228         }
 229
 230 error:
 231         return ret;
 232 }
 233
 234 /*
 235  * Send a get channel command to consumer using the given channel key.  The
 236  * channel object is populated and the stream list.
 237  *
 238  * Return 0 on success else a negative value.
 239  */
 240 int ust_consumer_get_channel(struct consumer_socket *socket,
 241                 struct ust_app_channel *ua_chan)
 242 {
 243         int ret;
 244         struct lttcomm_consumer_msg msg;
 245
 246         LTTNG_ASSERT(ua_chan);
 247         LTTNG_ASSERT(socket);
 248
 249         memset(&msg, 0, sizeof(msg));
 250         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 251         msg.u.get_channel.key = ua_chan->key;
 252
 253         pthread_mutex_lock(socket->lock);
 254         health_code_update();
 255
 256         /* Send command and wait for OK reply. */
 257         ret = consumer_send_msg(socket, &msg);
 258         if (ret < 0) {
 259                 goto error;
 260         }
 261
 262         /* First, get the channel from consumer. */
 263         ret = lttng_ust_ctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 264         if (ret < 0) {
 265                 if (ret != -EPIPE) {
 266                         ERR("Error recv channel from consumer %d with ret %d",
 267                                         *socket->fd_ptr, ret);
 268                 } else {
 269                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 270                 }
 271                 goto error;
 272         }
 273
 274         /* Next, get all streams. */
 275         while (1) {
 276                 struct ust_app_stream *stream;
 277
 278                 /* Create UST stream */
 279                 stream = ust_app_alloc_stream();
 280                 if (stream == NULL) {
 281                         ret = -ENOMEM;
 282                         goto error;
 283                 }
 284
 285                 /* Stream object is populated by this call if successful. */
 286                 ret = lttng_ust_ctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 287                 if (ret < 0) {
 288                         free(stream);
 289                         if (ret == -LTTNG_UST_ERR_NOENT) {
 290                                 DBG3("UST app consumer has no more stream available");
 291                                 break;
 292                         }
 293                         if (ret != -EPIPE) {
 294                                 ERR("Recv stream from consumer %d with ret %d",
 295                                                 *socket->fd_ptr, ret);
 296                         } else {
 297                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 298                         }
 299                         goto error;
 300                 }
 301
 302                 /* Order is important this is why a list is used. */
 303                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 304                 ua_chan->streams.count++;
 305
 306                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 307         }
 308
 309         /* This MUST match or else we have a synchronization problem. */
 310         LTTNG_ASSERT(ua_chan->expected_stream_count == ua_chan->streams.count);
 311
 312         /* Wait for confirmation that we can proceed with the streams. */
 313         ret = consumer_recv_status_reply(socket);
 314         if (ret < 0) {
 315                 goto error;
 316         }
 317
 318 error:
 319         health_code_update();
 320         pthread_mutex_unlock(socket->lock);
 321         return ret;
 322 }
 323
 324 /*
 325  * Send a destroy channel command to consumer using the given channel key.
 326  *
 327  * Note that this command MUST be used prior to a successful
 328  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 329  * the streams are dispatched to the consumer threads and MUST be teardown
 330  * through the hang up process.
 331  *
 332  * Return 0 on success else a negative value.
 333  */
 334 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 335                 struct ust_app_channel *ua_chan)
 336 {
 337         int ret;
 338         struct lttcomm_consumer_msg msg;
 339
 340         LTTNG_ASSERT(ua_chan);
 341         LTTNG_ASSERT(socket);
 342
 343         memset(&msg, 0, sizeof(msg));
 344         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 345         msg.u.destroy_channel.key = ua_chan->key;
 346
 347         pthread_mutex_lock(socket->lock);
 348         health_code_update();
 349
 350         ret = consumer_send_msg(socket, &msg);
 351         if (ret < 0) {
 352                 goto error;
 353         }
 354
 355 error:
 356         health_code_update();
 357         pthread_mutex_unlock(socket->lock);
 358         return ret;
 359 }
 360
 361 /*
 362  * Send a given stream to UST tracer.
 363  *
 364  * On success return 0 else a negative value.
 365  */
 366 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 367                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 368 {
 369         int ret;
 370
 371         LTTNG_ASSERT(app);
 372         LTTNG_ASSERT(stream);
 373         LTTNG_ASSERT(channel);
 374
 375         DBG2("UST consumer send stream to app %d", app->sock);
 376
 377         /* Relay stream to application. */
 378         pthread_mutex_lock(&app->sock_lock);
 379         ret = lttng_ust_ctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 380         pthread_mutex_unlock(&app->sock_lock);
 381         if (ret < 0) {
 382                 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 383                         DBG3("UST app send stream to ust failed. Application is dead. (pid: %d, sock: %d).",
 384                                         app->pid, app->sock);
 385                 } else if (ret == -EAGAIN) {
 386                         WARN("UST app send stream to ust failed. Communication time out (pid: %d, sock: %d).",
 387                                         app->pid, app->sock);
 388                 } else {
 389                         ERR("UST app send stream, handle %d, to ust failed with ret %d (pid: %d, sock: %d).",
 390                                         stream->obj->handle, ret, app->pid,
 391                                         app->sock);
 392                 }
 393                 goto error;
 394         }
 395         channel->handle = channel->obj->handle;
 396
 397 error:
 398         return ret;
 399 }
 400
 401 /*
 402  * Send channel previously received from the consumer to the UST tracer.
 403  *
 404  * On success return 0 else a negative value.
 405  */
 406 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 407                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 408 {
 409         int ret;
 410
 411         LTTNG_ASSERT(app);
 412         LTTNG_ASSERT(ua_sess);
 413         LTTNG_ASSERT(channel);
 414         LTTNG_ASSERT(channel->obj);
 415
 416         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 417                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 418
 419         /* Send stream to application. */
 420         pthread_mutex_lock(&app->sock_lock);
 421         ret = lttng_ust_ctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 422         pthread_mutex_unlock(&app->sock_lock);
 423         if (ret < 0) {
 424                 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 425                         DBG3("UST app send channel to ust failed. Application is dead (pid: %d, sock: %d).",
 426                                         app->pid, app->sock);
 427                 } else if (ret == -EAGAIN) {
 428                         WARN("UST app send channel to ust failed. Communication timeout (pid: %d, sock: %d).",
 429                                         app->pid, app->sock);
 430                 } else {
 431                         ERR("UST app send channel %s, to ust failed with ret %d (pid: %d, sock: %d).",
 432                                         channel->name, ret, app->pid,
 433                                         app->sock);
 434                 }
 435                 goto error;
 436         }
 437
 438 error:
 439         return ret;
 440 }
 441
 442 /*
 443  * Handle the metadata requests from the UST consumer
 444  *
 445  * Return 0 on success else a negative value.
 446  */
 447 int ust_consumer_metadata_request(struct consumer_socket *socket)
 448 {
 449         int ret;
 450         ssize_t ret_push;
 451         struct lttcomm_metadata_request_msg request;
 452         struct buffer_reg_uid *reg_uid;
 453         lsu::registry_session *ust_reg;
 454         struct lttcomm_consumer_msg msg;
 455
 456         LTTNG_ASSERT(socket);
 457
 458         rcu_read_lock();
 459         health_code_update();
 460
 461         /* Wait for a metadata request */
 462         pthread_mutex_lock(socket->lock);
 463         ret = consumer_socket_recv(socket, &request, sizeof(request));
 464         pthread_mutex_unlock(socket->lock);
 465         if (ret < 0) {
 466                 goto end;
 467         }
 468
 469         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 470                         request.session_id, request.key);
 471
 472         reg_uid = buffer_reg_uid_find(request.session_id,
 473                         request.bits_per_long, request.uid);
 474         if (reg_uid) {
 475                 ust_reg = reg_uid->registry->reg.ust;
 476         } else {
 477                 struct buffer_reg_pid *reg_pid =
 478                         buffer_reg_pid_find(request.session_id_per_pid);
 479                 if (!reg_pid) {
 480                         DBG("PID registry not found for session id %" PRIu64,
 481                                         request.session_id_per_pid);
 482
 483                         memset(&msg, 0, sizeof(msg));
 484                         msg.cmd_type = LTTNG_ERR_UND;
 485                         pthread_mutex_lock(socket->lock);
 486                         (void) consumer_send_msg(socket, &msg);
 487                         pthread_mutex_unlock(socket->lock);
 488                         /*
 489                          * This is possible since the session might have been destroyed
 490                          * during a consumer metadata request. So here, return gracefully
 491                          * because the destroy session will push the remaining metadata to
 492                          * the consumer.
 493                          */
 494                         ret = 0;
 495                         goto end;
 496                 }
 497                 ust_reg = reg_pid->registry->reg.ust;
 498         }
 499         LTTNG_ASSERT(ust_reg);
 500
 501         {
 502                 auto locked_ust_reg = ust_reg->lock();
 503                 ret_push = ust_app_push_metadata(locked_ust_reg, socket, 1);
 504         }
 505         if (ret_push == -EPIPE) {
 506                 DBG("Application or relay closed while pushing metadata");
 507         } else if (ret_push < 0) {
 508                 ERR("Pushing metadata");
 509                 ret = -1;
 510                 goto end;
 511         } else {
 512                 DBG("UST Consumer metadata pushed successfully");
 513         }
 514         ret = 0;
 515
 516 end:
 517         rcu_read_unlock();
 518         return ret;
 519 }