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