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

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