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

   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 <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <inttypes.h>
  14
  15 #include <common/compat/errno.h>
  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 *ust_reg_chan;
  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         LTTNG_ASSERT(ua_sess);
  52         LTTNG_ASSERT(ua_chan);
  53         LTTNG_ASSERT(socket);
  54         LTTNG_ASSERT(consumer);
  55         LTTNG_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_ABI_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                 ust_reg_chan = ust_registry_channel_find(registry, chan_reg_key);
 109                 LTTNG_ASSERT(ust_reg_chan);
 110                 chan_id = ust_reg_chan->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_ABI_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_sess->live_timer_interval != 0,
 140                         ua_chan->monitor_timer_interval,
 141                         output,
 142                         (int) ua_chan->attr.type,
 143                         ua_sess->tracing_id,
 144                         &pathname[consumer_path_offset],
 145                         ua_chan->name,
 146                         consumer->net_seq_index,
 147                         ua_chan->key,
 148                         registry->uuid,
 149                         chan_id,
 150                         ua_chan->tracefile_size,
 151                         ua_chan->tracefile_count,
 152                         ua_sess->id,
 153                         ua_sess->output_traces,
 154                         lttng_credentials_get_uid(&ua_sess->real_credentials),
 155                         ua_chan->attr.blocking_timeout,
 156                         root_shm_path, shm_path,
 157                         trace_chunk,
 158                         &ua_sess->effective_credentials);
 159
 160         health_code_update();
 161
 162         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 163         if (ret < 0) {
 164                 goto error;
 165         }
 166
 167         ret = consumer_recv_status_channel(socket, &key,
 168                         &ua_chan->expected_stream_count);
 169         if (ret < 0) {
 170                 goto error;
 171         }
 172         /* Communication protocol error. */
 173         LTTNG_ASSERT(key == ua_chan->key);
 174         /* We need at least one where 1 stream for 1 cpu. */
 175         if (ua_sess->output_traces) {
 176                 LTTNG_ASSERT(ua_chan->expected_stream_count > 0);
 177         }
 178
 179         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 180                         ua_chan->expected_stream_count);
 181
 182 error:
 183         free(pathname);
 184         health_code_update();
 185         return ret;
 186 }
 187
 188 /*
 189  * Ask consumer to create a channel for a given session.
 190  *
 191  * Session list and rcu read side locks must be held by the caller.
 192  *
 193  * Returns 0 on success else a negative value.
 194  */
 195 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 196                 struct ust_app_channel *ua_chan,
 197                 struct consumer_output *consumer,
 198                 struct consumer_socket *socket,
 199                 struct ust_registry_session *registry,
 200                 struct lttng_trace_chunk * trace_chunk)
 201 {
 202         int ret;
 203
 204         LTTNG_ASSERT(ua_sess);
 205         LTTNG_ASSERT(ua_chan);
 206         LTTNG_ASSERT(consumer);
 207         LTTNG_ASSERT(socket);
 208         LTTNG_ASSERT(registry);
 209
 210         if (!consumer->enabled) {
 211                 ret = -LTTNG_ERR_NO_CONSUMER;
 212                 DBG3("Consumer is disabled");
 213                 goto error;
 214         }
 215
 216         pthread_mutex_lock(socket->lock);
 217         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry,
 218                         trace_chunk);
 219         pthread_mutex_unlock(socket->lock);
 220         if (ret < 0) {
 221                 ERR("ask_channel_creation consumer command failed");
 222                 goto error;
 223         }
 224
 225 error:
 226         return ret;
 227 }
 228
 229 /*
 230  * Send a get channel command to consumer using the given channel key.  The
 231  * channel object is populated and the stream list.
 232  *
 233  * Return 0 on success else a negative value.
 234  */
 235 int ust_consumer_get_channel(struct consumer_socket *socket,
 236                 struct ust_app_channel *ua_chan)
 237 {
 238         int ret;
 239         struct lttcomm_consumer_msg msg;
 240
 241         LTTNG_ASSERT(ua_chan);
 242         LTTNG_ASSERT(socket);
 243
 244         memset(&msg, 0, sizeof(msg));
 245         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 246         msg.u.get_channel.key = ua_chan->key;
 247
 248         pthread_mutex_lock(socket->lock);
 249         health_code_update();
 250
 251         /* Send command and wait for OK reply. */
 252         ret = consumer_send_msg(socket, &msg);
 253         if (ret < 0) {
 254                 goto error;
 255         }
 256
 257         /* First, get the channel from consumer. */
 258         ret = lttng_ust_ctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 259         if (ret < 0) {
 260                 if (ret != -EPIPE) {
 261                         ERR("Error recv channel from consumer %d with ret %d",
 262                                         *socket->fd_ptr, ret);
 263                 } else {
 264                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 265                 }
 266                 goto error;
 267         }
 268
 269         /* Next, get all streams. */
 270         while (1) {
 271                 struct ust_app_stream *stream;
 272
 273                 /* Create UST stream */
 274                 stream = ust_app_alloc_stream();
 275                 if (stream == NULL) {
 276                         ret = -ENOMEM;
 277                         goto error;
 278                 }
 279
 280                 /* Stream object is populated by this call if successful. */
 281                 ret = lttng_ust_ctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 282                 if (ret < 0) {
 283                         free(stream);
 284                         if (ret == -LTTNG_UST_ERR_NOENT) {
 285                                 DBG3("UST app consumer has no more stream available");
 286                                 break;
 287                         }
 288                         if (ret != -EPIPE) {
 289                                 ERR("Recv stream from consumer %d with ret %d",
 290                                                 *socket->fd_ptr, ret);
 291                         } else {
 292                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 293                         }
 294                         goto error;
 295                 }
 296
 297                 /* Order is important this is why a list is used. */
 298                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 299                 ua_chan->streams.count++;
 300
 301                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 302         }
 303
 304         /* This MUST match or else we have a synchronization problem. */
 305         LTTNG_ASSERT(ua_chan->expected_stream_count == ua_chan->streams.count);
 306
 307         /* Wait for confirmation that we can proceed with the streams. */
 308         ret = consumer_recv_status_reply(socket);
 309         if (ret < 0) {
 310                 goto error;
 311         }
 312
 313 error:
 314         health_code_update();
 315         pthread_mutex_unlock(socket->lock);
 316         return ret;
 317 }
 318
 319 /*
 320  * Send a destroy channel command to consumer using the given channel key.
 321  *
 322  * Note that this command MUST be used prior to a successful
 323  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 324  * the streams are dispatched to the consumer threads and MUST be teardown
 325  * through the hang up process.
 326  *
 327  * Return 0 on success else a negative value.
 328  */
 329 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 330                 struct ust_app_channel *ua_chan)
 331 {
 332         int ret;
 333         struct lttcomm_consumer_msg msg;
 334
 335         LTTNG_ASSERT(ua_chan);
 336         LTTNG_ASSERT(socket);
 337
 338         memset(&msg, 0, sizeof(msg));
 339         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 340         msg.u.destroy_channel.key = ua_chan->key;
 341
 342         pthread_mutex_lock(socket->lock);
 343         health_code_update();
 344
 345         ret = consumer_send_msg(socket, &msg);
 346         if (ret < 0) {
 347                 goto error;
 348         }
 349
 350 error:
 351         health_code_update();
 352         pthread_mutex_unlock(socket->lock);
 353         return ret;
 354 }
 355
 356 /*
 357  * Send a given stream to UST tracer.
 358  *
 359  * On success return 0 else a negative value.
 360  */
 361 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 362                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 363 {
 364         int ret;
 365
 366         LTTNG_ASSERT(app);
 367         LTTNG_ASSERT(stream);
 368         LTTNG_ASSERT(channel);
 369
 370         DBG2("UST consumer send stream to app %d", app->sock);
 371
 372         /* Relay stream to application. */
 373         pthread_mutex_lock(&app->sock_lock);
 374         ret = lttng_ust_ctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 375         pthread_mutex_unlock(&app->sock_lock);
 376         if (ret < 0) {
 377                 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 378                         DBG3("UST app send stream to ust failed. Application is dead. (pid: %d, sock: %d).",
 379                                         app->pid, app->sock);
 380                 } else if (ret == -EAGAIN) {
 381                         WARN("UST app send stream to ust failed. Communication time out (pid: %d, sock: %d).",
 382                                         app->pid, app->sock);
 383                 } else {
 384                         ERR("UST app send stream, handle %d, to ust failed with ret %d (pid: %d, sock: %d).",
 385                                         stream->obj->handle, ret, app->pid,
 386                                         app->sock);
 387                 }
 388                 goto error;
 389         }
 390         channel->handle = channel->obj->handle;
 391
 392 error:
 393         return ret;
 394 }
 395
 396 /*
 397  * Send channel previously received from the consumer to the UST tracer.
 398  *
 399  * On success return 0 else a negative value.
 400  */
 401 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 402                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 403 {
 404         int ret;
 405
 406         LTTNG_ASSERT(app);
 407         LTTNG_ASSERT(ua_sess);
 408         LTTNG_ASSERT(channel);
 409         LTTNG_ASSERT(channel->obj);
 410
 411         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 412                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 413
 414         /* Send stream to application. */
 415         pthread_mutex_lock(&app->sock_lock);
 416         ret = lttng_ust_ctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 417         pthread_mutex_unlock(&app->sock_lock);
 418         if (ret < 0) {
 419                 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 420                         DBG3("UST app send channel to ust failed. Application is dead (pid: %d, sock: %d).",
 421                                         app->pid, app->sock);
 422                 } else if (ret == -EAGAIN) {
 423                         WARN("UST app send channel to ust failed. Communication timeout (pid: %d, sock: %d).",
 424                                         app->pid, app->sock);
 425                 } else {
 426                         ERR("UST app send channel %s, to ust failed with ret %d (pid: %d, sock: %d).",
 427                                         channel->name, ret, app->pid,
 428                                         app->sock);
 429                 }
 430                 goto error;
 431         }
 432
 433 error:
 434         return ret;
 435 }
 436
 437 /*
 438  * Handle the metadata requests from the UST consumer
 439  *
 440  * Return 0 on success else a negative value.
 441  */
 442 int ust_consumer_metadata_request(struct consumer_socket *socket)
 443 {
 444         int ret;
 445         ssize_t ret_push;
 446         struct lttcomm_metadata_request_msg request;
 447         struct buffer_reg_uid *reg_uid;
 448         struct ust_registry_session *ust_reg;
 449         struct lttcomm_consumer_msg msg;
 450
 451         LTTNG_ASSERT(socket);
 452
 453         rcu_read_lock();
 454         health_code_update();
 455
 456         /* Wait for a metadata request */
 457         pthread_mutex_lock(socket->lock);
 458         ret = consumer_socket_recv(socket, &request, sizeof(request));
 459         pthread_mutex_unlock(socket->lock);
 460         if (ret < 0) {
 461                 goto end;
 462         }
 463
 464         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 465                         request.session_id, request.key);
 466
 467         reg_uid = buffer_reg_uid_find(request.session_id,
 468                         request.bits_per_long, request.uid);
 469         if (reg_uid) {
 470                 ust_reg = reg_uid->registry->reg.ust;
 471         } else {
 472                 struct buffer_reg_pid *reg_pid =
 473                         buffer_reg_pid_find(request.session_id_per_pid);
 474                 if (!reg_pid) {
 475                         DBG("PID registry not found for session id %" PRIu64,
 476                                         request.session_id_per_pid);
 477
 478                         memset(&msg, 0, sizeof(msg));
 479                         msg.cmd_type = LTTNG_ERR_UND;
 480                         pthread_mutex_lock(socket->lock);
 481                         (void) consumer_send_msg(socket, &msg);
 482                         pthread_mutex_unlock(socket->lock);
 483                         /*
 484                          * This is possible since the session might have been destroyed
 485                          * during a consumer metadata request. So here, return gracefully
 486                          * because the destroy session will push the remaining metadata to
 487                          * the consumer.
 488                          */
 489                         ret = 0;
 490                         goto end;
 491                 }
 492                 ust_reg = reg_pid->registry->reg.ust;
 493         }
 494         LTTNG_ASSERT(ust_reg);
 495
 496         pthread_mutex_lock(&ust_reg->lock);
 497         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 498         pthread_mutex_unlock(&ust_reg->lock);
 499         if (ret_push == -EPIPE) {
 500                 DBG("Application or relay closed while pushing metadata");
 501         } else if (ret_push < 0) {
 502                 ERR("Pushing metadata");
 503                 ret = -1;
 504                 goto end;
 505         } else {
 506                 DBG("UST Consumer metadata pushed successfully");
 507         }
 508         ret = 0;
 509
 510 end:
 511         rcu_read_unlock();
 512         return ret;
 513 }