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