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 "buffer-registry.h"
  34 #include "session.h"
  35 #include "lttng-sessiond.h"
  36
  37 /*
  38  * Return allocated full pathname of the session using the consumer trace path
  39  * and subdir if available. On a successful allocation, the directory of the
  40  * trace is created with the session credentials.
  41  *
  42  * The caller can safely free(3) the returned value. On error, NULL is
  43  * returned.
  44  */
  45 static char *setup_trace_path(struct consumer_output *consumer,
  46                 struct ust_app_session *ua_sess)
  47 {
  48         int ret;
  49         char *pathname;
  50
  51         assert(consumer);
  52         assert(ua_sess);
  53
  54         health_code_update();
  55
  56         /* Allocate our self the string to make sure we never exceed PATH_MAX. */
  57         pathname = zmalloc(PATH_MAX);
  58         if (!pathname) {
  59                 goto error;
  60         }
  61
  62         /* Get correct path name destination */
  63         if (consumer->type == CONSUMER_DST_LOCAL) {
  64                 /* Set application path to the destination path */
  65                 ret = snprintf(pathname, PATH_MAX, "%s%s%s%s",
  66                                 consumer->dst.session_root_path,
  67                                 consumer->chunk_path,
  68                                 consumer->subdir, ua_sess->path);
  69                 if (ret < 0) {
  70                         PERROR("snprintf channel path");
  71                         goto error;
  72                 }
  73
  74                 /* Create directory. Ignore if exist. */
  75                 ret = run_as_mkdir_recursive(pathname, S_IRWXU | S_IRWXG,
  76                                 ua_sess->euid, ua_sess->egid);
  77                 if (ret < 0) {
  78                         if (errno != EEXIST) {
  79                                 ERR("Trace directory creation error");
  80                                 goto error;
  81                         }
  82                 }
  83         } else {
  84                 ret = snprintf(pathname, PATH_MAX, "%s%s", consumer->subdir,
  85                                 ua_sess->path);
  86                 if (ret < 0) {
  87                         PERROR("snprintf channel path");
  88                         goto error;
  89                 }
  90         }
  91
  92         return pathname;
  93
  94 error:
  95         free(pathname);
  96         return NULL;
  97 }
  98
  99 /*
 100  * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
 101  *
 102  * Consumer socket lock MUST be acquired before calling this.
 103  */
 104 static int ask_channel_creation(struct ust_app_session *ua_sess,
 105                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 106                 struct consumer_socket *socket, struct ust_registry_session *registry)
 107 {
 108         int ret, output;
 109         uint32_t chan_id;
 110         uint64_t key, chan_reg_key;
 111         char *pathname = NULL;
 112         struct lttcomm_consumer_msg msg;
 113         struct ust_registry_channel *chan_reg;
 114         char shm_path[PATH_MAX] = "";
 115         char root_shm_path[PATH_MAX] = "";
 116
 117         assert(ua_sess);
 118         assert(ua_chan);
 119         assert(socket);
 120         assert(consumer);
 121         assert(registry);
 122
 123         DBG2("Asking UST consumer for channel");
 124
 125         /* Get and create full trace path of session. */
 126         if (ua_sess->output_traces) {
 127                 pathname = setup_trace_path(consumer, ua_sess);
 128                 if (!pathname) {
 129                         ret = -1;
 130                         goto error;
 131                 }
 132         }
 133
 134         /* Depending on the buffer type, a different channel key is used. */
 135         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 136                 chan_reg_key = ua_chan->tracing_channel_id;
 137         } else {
 138                 chan_reg_key = ua_chan->key;
 139         }
 140
 141         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 142                 chan_id = -1U;
 143                 /*
 144                  * Metadata channels shm_path (buffers) are handled within
 145                  * session daemon. Consumer daemon should not try to create
 146                  * those buffer files.
 147                  */
 148         } else {
 149                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 150                 assert(chan_reg);
 151                 chan_id = chan_reg->chan_id;
 152                 if (ua_sess->shm_path[0]) {
 153                         strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
 154                         shm_path[sizeof(shm_path) - 1] = '\0';
 155                         strncat(shm_path, "/",
 156                                 sizeof(shm_path) - strlen(shm_path) - 1);
 157                         strncat(shm_path, ua_chan->name,
 158                                         sizeof(shm_path) - strlen(shm_path) - 1);
 159                                 strncat(shm_path, "_",
 160                                         sizeof(shm_path) - strlen(shm_path) - 1);
 161                 }
 162                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 163                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 164         }
 165
 166         switch (ua_chan->attr.output) {
 167         case LTTNG_UST_MMAP:
 168         default:
 169                 output = LTTNG_EVENT_MMAP;
 170                 break;
 171         }
 172
 173         consumer_init_ask_channel_comm_msg(&msg,
 174                         ua_chan->attr.subbuf_size,
 175                         ua_chan->attr.num_subbuf,
 176                         ua_chan->attr.overwrite,
 177                         ua_chan->attr.switch_timer_interval,
 178                         ua_chan->attr.read_timer_interval,
 179                         ua_sess->live_timer_interval,
 180                         ua_chan->monitor_timer_interval,
 181                         output,
 182                         (int) ua_chan->attr.type,
 183                         ua_sess->tracing_id,
 184                         pathname,
 185                         ua_chan->name,
 186                         ua_sess->euid,
 187                         ua_sess->egid,
 188                         consumer->net_seq_index,
 189                         ua_chan->key,
 190                         registry->uuid,
 191                         chan_id,
 192                         ua_chan->tracefile_size,
 193                         ua_chan->tracefile_count,
 194                         ua_sess->id,
 195                         ua_sess->output_traces,
 196                         ua_sess->uid,
 197                         ua_chan->attr.blocking_timeout,
 198                         root_shm_path, shm_path);
 199
 200         health_code_update();
 201
 202         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 203         if (ret < 0) {
 204                 goto error;
 205         }
 206
 207         ret = consumer_recv_status_channel(socket, &key,
 208                         &ua_chan->expected_stream_count);
 209         if (ret < 0) {
 210                 goto error;
 211         }
 212         /* Communication protocol error. */
 213         assert(key == ua_chan->key);
 214         /* We need at least one where 1 stream for 1 cpu. */
 215         if (ua_sess->output_traces) {
 216                 assert(ua_chan->expected_stream_count > 0);
 217         }
 218
 219         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 220                         ua_chan->expected_stream_count);
 221
 222 error:
 223         free(pathname);
 224         health_code_update();
 225         return ret;
 226 }
 227
 228 /*
 229  * Ask consumer to create a channel for a given session.
 230  *
 231  * Session list and rcu read side locks must be held by the caller.
 232  *
 233  * Returns 0 on success else a negative value.
 234  */
 235 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 236                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 237                 struct consumer_socket *socket, struct ust_registry_session *registry)
 238 {
 239         int ret;
 240         struct ltt_session *session;
 241
 242         assert(ua_sess);
 243         assert(ua_chan);
 244         assert(consumer);
 245         assert(socket);
 246         assert(registry);
 247
 248         if (!consumer->enabled) {
 249                 ret = -LTTNG_ERR_NO_CONSUMER;
 250                 DBG3("Consumer is disabled");
 251                 goto error;
 252         }
 253
 254         session = session_find_by_id(ua_sess->tracing_id);
 255         assert(session);
 256
 257         pthread_mutex_lock(socket->lock);
 258         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 259         pthread_mutex_unlock(socket->lock);
 260         if (ret < 0) {
 261                 ERR("ask_channel_creation consumer command failed");
 262                 goto error;
 263         }
 264
 265 error:
 266         return ret;
 267 }
 268
 269 /*
 270  * Send a get channel command to consumer using the given channel key.  The
 271  * channel object is populated and the stream list.
 272  *
 273  * Return 0 on success else a negative value.
 274  */
 275 int ust_consumer_get_channel(struct consumer_socket *socket,
 276                 struct ust_app_channel *ua_chan)
 277 {
 278         int ret;
 279         struct lttcomm_consumer_msg msg;
 280
 281         assert(ua_chan);
 282         assert(socket);
 283
 284         memset(&msg, 0, sizeof(msg));
 285         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 286         msg.u.get_channel.key = ua_chan->key;
 287
 288         pthread_mutex_lock(socket->lock);
 289         health_code_update();
 290
 291         /* Send command and wait for OK reply. */
 292         ret = consumer_send_msg(socket, &msg);
 293         if (ret < 0) {
 294                 goto error;
 295         }
 296
 297         /* First, get the channel from consumer. */
 298         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 299         if (ret < 0) {
 300                 if (ret != -EPIPE) {
 301                         ERR("Error recv channel from consumer %d with ret %d",
 302                                         *socket->fd_ptr, ret);
 303                 } else {
 304                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 305                 }
 306                 goto error;
 307         }
 308
 309         /* Next, get all streams. */
 310         while (1) {
 311                 struct ust_app_stream *stream;
 312
 313                 /* Create UST stream */
 314                 stream = ust_app_alloc_stream();
 315                 if (stream == NULL) {
 316                         ret = -ENOMEM;
 317                         goto error;
 318                 }
 319
 320                 /* Stream object is populated by this call if successful. */
 321                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 322                 if (ret < 0) {
 323                         free(stream);
 324                         if (ret == -LTTNG_UST_ERR_NOENT) {
 325                                 DBG3("UST app consumer has no more stream available");
 326                                 break;
 327                         }
 328                         if (ret != -EPIPE) {
 329                                 ERR("Recv stream from consumer %d with ret %d",
 330                                                 *socket->fd_ptr, ret);
 331                         } else {
 332                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 333                         }
 334                         goto error;
 335                 }
 336
 337                 /* Order is important this is why a list is used. */
 338                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 339                 ua_chan->streams.count++;
 340
 341                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 342         }
 343
 344         /* This MUST match or else we have a synchronization problem. */
 345         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 346
 347         /* Wait for confirmation that we can proceed with the streams. */
 348         ret = consumer_recv_status_reply(socket);
 349         if (ret < 0) {
 350                 goto error;
 351         }
 352
 353 error:
 354         health_code_update();
 355         pthread_mutex_unlock(socket->lock);
 356         return ret;
 357 }
 358
 359 /*
 360  * Send a destroy channel command to consumer using the given channel key.
 361  *
 362  * Note that this command MUST be used prior to a successful
 363  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 364  * the streams are dispatched to the consumer threads and MUST be teardown
 365  * through the hang up process.
 366  *
 367  * Return 0 on success else a negative value.
 368  */
 369 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 370                 struct ust_app_channel *ua_chan)
 371 {
 372         int ret;
 373         struct lttcomm_consumer_msg msg;
 374
 375         assert(ua_chan);
 376         assert(socket);
 377
 378         memset(&msg, 0, sizeof(msg));
 379         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 380         msg.u.destroy_channel.key = ua_chan->key;
 381
 382         pthread_mutex_lock(socket->lock);
 383         health_code_update();
 384
 385         ret = consumer_send_msg(socket, &msg);
 386         if (ret < 0) {
 387                 goto error;
 388         }
 389
 390 error:
 391         health_code_update();
 392         pthread_mutex_unlock(socket->lock);
 393         return ret;
 394 }
 395
 396 /*
 397  * Send a given stream to UST tracer.
 398  *
 399  * On success return 0 else a negative value.
 400  */
 401 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 402                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 403 {
 404         int ret;
 405
 406         assert(app);
 407         assert(stream);
 408         assert(channel);
 409
 410         DBG2("UST consumer send stream to app %d", app->sock);
 411
 412         /* Relay stream to application. */
 413         pthread_mutex_lock(&app->sock_lock);
 414         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 415         pthread_mutex_unlock(&app->sock_lock);
 416         if (ret < 0) {
 417                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 418                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 419                                         stream->obj->handle, app->pid, ret);
 420                 } else {
 421                         DBG3("UST app send stream to ust failed. Application is dead.");
 422                 }
 423                 goto error;
 424         }
 425         channel->handle = channel->obj->handle;
 426
 427 error:
 428         return ret;
 429 }
 430
 431 /*
 432  * Send channel previously received from the consumer to the UST tracer.
 433  *
 434  * On success return 0 else a negative value.
 435  */
 436 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 437                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 438 {
 439         int ret;
 440
 441         assert(app);
 442         assert(ua_sess);
 443         assert(channel);
 444         assert(channel->obj);
 445
 446         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 447                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 448
 449         /* Send stream to application. */
 450         pthread_mutex_lock(&app->sock_lock);
 451         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 452         pthread_mutex_unlock(&app->sock_lock);
 453         if (ret < 0) {
 454                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 455                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 456                                         channel->name, app->pid, ret);
 457                 } else {
 458                         DBG3("UST app send channel to ust failed. Application is dead.");
 459                 }
 460                 goto error;
 461         }
 462
 463 error:
 464         return ret;
 465 }
 466
 467 /*
 468  * Handle the metadata requests from the UST consumer
 469  *
 470  * Return 0 on success else a negative value.
 471  */
 472 int ust_consumer_metadata_request(struct consumer_socket *socket)
 473 {
 474         int ret;
 475         ssize_t ret_push;
 476         struct lttcomm_metadata_request_msg request;
 477         struct buffer_reg_uid *reg_uid;
 478         struct ust_registry_session *ust_reg;
 479         struct lttcomm_consumer_msg msg;
 480
 481         assert(socket);
 482
 483         rcu_read_lock();
 484         health_code_update();
 485
 486         /* Wait for a metadata request */
 487         pthread_mutex_lock(socket->lock);
 488         ret = consumer_socket_recv(socket, &request, sizeof(request));
 489         pthread_mutex_unlock(socket->lock);
 490         if (ret < 0) {
 491                 goto end;
 492         }
 493
 494         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 495                         request.session_id, request.key);
 496
 497         reg_uid = buffer_reg_uid_find(request.session_id,
 498                         request.bits_per_long, request.uid);
 499         if (reg_uid) {
 500                 ust_reg = reg_uid->registry->reg.ust;
 501         } else {
 502                 struct buffer_reg_pid *reg_pid =
 503                         buffer_reg_pid_find(request.session_id_per_pid);
 504                 if (!reg_pid) {
 505                         DBG("PID registry not found for session id %" PRIu64,
 506                                         request.session_id_per_pid);
 507
 508                         memset(&msg, 0, sizeof(msg));
 509                         msg.cmd_type = LTTNG_ERR_UND;
 510                         (void) consumer_send_msg(socket, &msg);
 511                         /*
 512                          * This is possible since the session might have been destroyed
 513                          * during a consumer metadata request. So here, return gracefully
 514                          * because the destroy session will push the remaining metadata to
 515                          * the consumer.
 516                          */
 517                         ret = 0;
 518                         goto end;
 519                 }
 520                 ust_reg = reg_pid->registry->reg.ust;
 521         }
 522         assert(ust_reg);
 523
 524         pthread_mutex_lock(&ust_reg->lock);
 525         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 526         pthread_mutex_unlock(&ust_reg->lock);
 527         if (ret_push == -EPIPE) {
 528                 DBG("Application or relay closed while pushing metadata");
 529         } else if (ret_push < 0) {
 530                 ERR("Pushing metadata");
 531                 ret = -1;
 532                 goto end;
 533         } else {
 534                 DBG("UST Consumer metadata pushed successfully");
 535         }
 536         ret = 0;
 537
 538 end:
 539         rcu_read_unlock();
 540         return ret;
 541 }