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  * Return allocated full pathname of the session using the consumer trace path
  40  * and subdir if available. On a successful allocation, the directory of the
  41  * trace is created with the session credentials.
  42  *
  43  * The caller can safely free(3) the returned value. On error, NULL is
  44  * returned.
  45  */
  46 static char *setup_trace_path(struct consumer_output *consumer,
  47                 struct ust_app_session *ua_sess)
  48 {
  49         int ret;
  50         char *pathname;
  51
  52         assert(consumer);
  53         assert(ua_sess);
  54
  55         health_code_update();
  56
  57         /* Allocate our self the string to make sure we never exceed PATH_MAX. */
  58         pathname = zmalloc(PATH_MAX);
  59         if (!pathname) {
  60                 goto error;
  61         }
  62
  63         /* Get correct path name destination */
  64         if (consumer->type == CONSUMER_DST_LOCAL) {
  65                 /* Set application path to the destination path */
  66                 ret = snprintf(pathname, PATH_MAX, "%s%s%s",
  67                                 consumer->dst.trace_path, consumer->subdir, ua_sess->path);
  68                 if (ret < 0) {
  69                         PERROR("snprintf channel path");
  70                         goto error;
  71                 }
  72
  73                 /* Create directory. Ignore if exist. */
  74                 ret = run_as_mkdir_recursive(pathname, S_IRWXU | S_IRWXG,
  75                                 ua_sess->euid, ua_sess->egid);
  76                 if (ret < 0) {
  77                         if (errno != EEXIST) {
  78                                 ERR("Trace directory creation error");
  79                                 goto error;
  80                         }
  81                 }
  82         } else {
  83                 ret = snprintf(pathname, PATH_MAX, "%s%s", consumer->subdir,
  84                                 ua_sess->path);
  85                 if (ret < 0) {
  86                         PERROR("snprintf channel path");
  87                         goto error;
  88                 }
  89         }
  90
  91         return pathname;
  92
  93 error:
  94         free(pathname);
  95         return NULL;
  96 }
  97
  98 /*
  99  * Send a single channel to the consumer using command ASK_CHANNEL_CREATION.
 100  *
 101  * Consumer socket lock MUST be acquired before calling this.
 102  */
 103 static int ask_channel_creation(struct ust_app_session *ua_sess,
 104                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 105                 struct consumer_socket *socket, struct ust_registry_session *registry)
 106 {
 107         int ret, output;
 108         uint32_t chan_id;
 109         uint64_t key, chan_reg_key;
 110         char *pathname = NULL;
 111         struct lttcomm_consumer_msg msg;
 112         struct ust_registry_channel *chan_reg;
 113         char shm_path[PATH_MAX] = "";
 114         char root_shm_path[PATH_MAX] = "";
 115
 116         assert(ua_sess);
 117         assert(ua_chan);
 118         assert(socket);
 119         assert(consumer);
 120         assert(registry);
 121
 122         DBG2("Asking UST consumer for channel");
 123
 124         /* Get and create full trace path of session. */
 125         if (ua_sess->output_traces) {
 126                 pathname = setup_trace_path(consumer, ua_sess);
 127                 if (!pathname) {
 128                         ret = -1;
 129                         goto error;
 130                 }
 131         }
 132
 133         /* Depending on the buffer type, a different channel key is used. */
 134         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 135                 chan_reg_key = ua_chan->tracing_channel_id;
 136         } else {
 137                 chan_reg_key = ua_chan->key;
 138         }
 139
 140         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 141                 chan_id = -1U;
 142                 /*
 143                  * Metadata channels shm_path (buffers) are handled within
 144                  * session daemon. Consumer daemon should not try to create
 145                  * those buffer files.
 146                  */
 147         } else {
 148                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 149                 assert(chan_reg);
 150                 chan_id = chan_reg->chan_id;
 151                 if (ua_sess->shm_path[0]) {
 152                         strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
 153                         shm_path[sizeof(shm_path) - 1] = '\0';
 154                         strncat(shm_path, "/",
 155                                 sizeof(shm_path) - strlen(shm_path) - 1);
 156                         strncat(shm_path, ua_chan->name,
 157                                         sizeof(shm_path) - strlen(shm_path) - 1);
 158                                 strncat(shm_path, "_",
 159                                         sizeof(shm_path) - strlen(shm_path) - 1);
 160                 }
 161                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 162                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 163         }
 164
 165         switch (ua_chan->attr.output) {
 166         case LTTNG_UST_MMAP:
 167         default:
 168                 output = LTTNG_EVENT_MMAP;
 169                 break;
 170         }
 171
 172         consumer_init_ask_channel_comm_msg(&msg,
 173                         ua_chan->attr.subbuf_size,
 174                         ua_chan->attr.num_subbuf,
 175                         ua_chan->attr.overwrite,
 176                         ua_chan->attr.switch_timer_interval,
 177                         ua_chan->attr.read_timer_interval,
 178                         ua_sess->live_timer_interval,
 179                         ua_chan->monitor_timer_interval,
 180                         output,
 181                         (int) ua_chan->attr.type,
 182                         ua_sess->tracing_id,
 183                         pathname,
 184                         ua_chan->name,
 185                         ua_sess->euid,
 186                         ua_sess->egid,
 187                         consumer->net_seq_index,
 188                         ua_chan->key,
 189                         registry->uuid,
 190                         chan_id,
 191                         ua_chan->tracefile_size,
 192                         ua_chan->tracefile_count,
 193                         ua_sess->id,
 194                         ua_sess->output_traces,
 195                         ua_sess->uid,
 196                         ua_chan->attr.blocking_timeout,
 197                         root_shm_path, shm_path);
 198
 199         health_code_update();
 200
 201         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 202         if (ret < 0) {
 203                 goto error;
 204         }
 205
 206         ret = consumer_recv_status_channel(socket, &key,
 207                         &ua_chan->expected_stream_count);
 208         if (ret < 0) {
 209                 goto error;
 210         }
 211         /* Communication protocol error. */
 212         assert(key == ua_chan->key);
 213         /* We need at least one where 1 stream for 1 cpu. */
 214         if (ua_sess->output_traces) {
 215                 assert(ua_chan->expected_stream_count > 0);
 216         }
 217
 218         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 219                         ua_chan->expected_stream_count);
 220
 221 error:
 222         free(pathname);
 223         health_code_update();
 224         return ret;
 225 }
 226
 227 /*
 228  * Ask consumer to create a channel for a given session.
 229  *
 230  * Session list and rcu read side locks must be held by the caller.
 231  *
 232  * Returns 0 on success else a negative value.
 233  */
 234 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 235                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 236                 struct consumer_socket *socket, struct ust_registry_session *registry)
 237 {
 238         int ret;
 239         struct ltt_session *session;
 240
 241         assert(ua_sess);
 242         assert(ua_chan);
 243         assert(consumer);
 244         assert(socket);
 245         assert(registry);
 246
 247         if (!consumer->enabled) {
 248                 ret = -LTTNG_ERR_NO_CONSUMER;
 249                 DBG3("Consumer is disabled");
 250                 goto error;
 251         }
 252
 253         session = session_find_by_id(ua_sess->tracing_id);
 254         assert(session);
 255
 256         pthread_mutex_lock(socket->lock);
 257         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 258         pthread_mutex_unlock(socket->lock);
 259         if (ret < 0) {
 260                 ERR("ask_channel_creation consumer command failed");
 261                 goto error;
 262         }
 263
 264 error:
 265         return ret;
 266 }
 267
 268 /*
 269  * Send a get channel command to consumer using the given channel key.  The
 270  * channel object is populated and the stream list.
 271  *
 272  * Return 0 on success else a negative value.
 273  */
 274 int ust_consumer_get_channel(struct consumer_socket *socket,
 275                 struct ust_app_channel *ua_chan)
 276 {
 277         int ret;
 278         struct lttcomm_consumer_msg msg;
 279
 280         assert(ua_chan);
 281         assert(socket);
 282
 283         memset(&msg, 0, sizeof(msg));
 284         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 285         msg.u.get_channel.key = ua_chan->key;
 286
 287         pthread_mutex_lock(socket->lock);
 288         health_code_update();
 289
 290         /* Send command and wait for OK reply. */
 291         ret = consumer_send_msg(socket, &msg);
 292         if (ret < 0) {
 293                 goto error;
 294         }
 295
 296         /* First, get the channel from consumer. */
 297         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 298         if (ret < 0) {
 299                 if (ret != -EPIPE) {
 300                         ERR("Error recv channel from consumer %d with ret %d",
 301                                         *socket->fd_ptr, ret);
 302                 } else {
 303                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 304                 }
 305                 goto error;
 306         }
 307
 308         /* Next, get all streams. */
 309         while (1) {
 310                 struct ust_app_stream *stream;
 311
 312                 /* Create UST stream */
 313                 stream = ust_app_alloc_stream();
 314                 if (stream == NULL) {
 315                         ret = -ENOMEM;
 316                         goto error;
 317                 }
 318
 319                 /* Stream object is populated by this call if successful. */
 320                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 321                 if (ret < 0) {
 322                         free(stream);
 323                         if (ret == -LTTNG_UST_ERR_NOENT) {
 324                                 DBG3("UST app consumer has no more stream available");
 325                                 break;
 326                         }
 327                         if (ret != -EPIPE) {
 328                                 ERR("Recv stream from consumer %d with ret %d",
 329                                                 *socket->fd_ptr, ret);
 330                         } else {
 331                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 332                         }
 333                         goto error;
 334                 }
 335
 336                 /* Order is important this is why a list is used. */
 337                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 338                 ua_chan->streams.count++;
 339
 340                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 341         }
 342
 343         /* This MUST match or else we have a synchronization problem. */
 344         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 345
 346         /* Wait for confirmation that we can proceed with the streams. */
 347         ret = consumer_recv_status_reply(socket);
 348         if (ret < 0) {
 349                 goto error;
 350         }
 351
 352 error:
 353         health_code_update();
 354         pthread_mutex_unlock(socket->lock);
 355         return ret;
 356 }
 357
 358 /*
 359  * Send a destroy channel command to consumer using the given channel key.
 360  *
 361  * Note that this command MUST be used prior to a successful
 362  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 363  * the streams are dispatched to the consumer threads and MUST be teardown
 364  * through the hang up process.
 365  *
 366  * Return 0 on success else a negative value.
 367  */
 368 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 369                 struct ust_app_channel *ua_chan)
 370 {
 371         int ret;
 372         struct lttcomm_consumer_msg msg;
 373
 374         assert(ua_chan);
 375         assert(socket);
 376
 377         memset(&msg, 0, sizeof(msg));
 378         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 379         msg.u.destroy_channel.key = ua_chan->key;
 380
 381         pthread_mutex_lock(socket->lock);
 382         health_code_update();
 383
 384         ret = consumer_send_msg(socket, &msg);
 385         if (ret < 0) {
 386                 goto error;
 387         }
 388
 389 error:
 390         health_code_update();
 391         pthread_mutex_unlock(socket->lock);
 392         return ret;
 393 }
 394
 395 /*
 396  * Send a given stream to UST tracer.
 397  *
 398  * On success return 0 else a negative value.
 399  */
 400 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 401                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 402 {
 403         int ret;
 404
 405         assert(app);
 406         assert(stream);
 407         assert(channel);
 408
 409         DBG2("UST consumer send stream to app %d", app->sock);
 410
 411         /* Relay stream to application. */
 412         pthread_mutex_lock(&app->sock_lock);
 413         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 414         pthread_mutex_unlock(&app->sock_lock);
 415         if (ret < 0) {
 416                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 417                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 418                                         stream->obj->handle, app->pid, ret);
 419                 } else {
 420                         DBG3("UST app send stream to ust failed. Application is dead.");
 421                 }
 422                 goto error;
 423         }
 424         channel->handle = channel->obj->handle;
 425
 426 error:
 427         return ret;
 428 }
 429
 430 /*
 431  * Send channel previously received from the consumer to the UST tracer.
 432  *
 433  * On success return 0 else a negative value.
 434  */
 435 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 436                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 437 {
 438         int ret;
 439
 440         assert(app);
 441         assert(ua_sess);
 442         assert(channel);
 443         assert(channel->obj);
 444
 445         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 446                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 447
 448         /* Send stream to application. */
 449         pthread_mutex_lock(&app->sock_lock);
 450         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 451         pthread_mutex_unlock(&app->sock_lock);
 452         if (ret < 0) {
 453                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 454                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 455                                         channel->name, app->pid, ret);
 456                 } else {
 457                         DBG3("UST app send channel to ust failed. Application is dead.");
 458                 }
 459                 goto error;
 460         }
 461
 462 error:
 463         return ret;
 464 }
 465
 466 /*
 467  * Handle the metadata requests from the UST consumer
 468  *
 469  * Return 0 on success else a negative value.
 470  */
 471 int ust_consumer_metadata_request(struct consumer_socket *socket)
 472 {
 473         int ret;
 474         ssize_t ret_push;
 475         struct lttcomm_metadata_request_msg request;
 476         struct buffer_reg_uid *reg_uid;
 477         struct ust_registry_session *ust_reg;
 478         struct lttcomm_consumer_msg msg;
 479
 480         assert(socket);
 481
 482         rcu_read_lock();
 483         health_code_update();
 484
 485         /* Wait for a metadata request */
 486         pthread_mutex_lock(socket->lock);
 487         ret = consumer_socket_recv(socket, &request, sizeof(request));
 488         pthread_mutex_unlock(socket->lock);
 489         if (ret < 0) {
 490                 goto end;
 491         }
 492
 493         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 494                         request.session_id, request.key);
 495
 496         reg_uid = buffer_reg_uid_find(request.session_id,
 497                         request.bits_per_long, request.uid);
 498         if (reg_uid) {
 499                 ust_reg = reg_uid->registry->reg.ust;
 500         } else {
 501                 struct buffer_reg_pid *reg_pid =
 502                         buffer_reg_pid_find(request.session_id_per_pid);
 503                 if (!reg_pid) {
 504                         DBG("PID registry not found for session id %" PRIu64,
 505                                         request.session_id_per_pid);
 506
 507                         memset(&msg, 0, sizeof(msg));
 508                         msg.cmd_type = LTTNG_ERR_UND;
 509                         pthread_mutex_lock(socket->lock);
 510                         (void) consumer_send_msg(socket, &msg);
 511                         pthread_mutex_unlock(socket->lock);
 512                         /*
 513                          * This is possible since the session might have been destroyed
 514                          * during a consumer metadata request. So here, return gracefully
 515                          * because the destroy session will push the remaining metadata to
 516                          * the consumer.
 517                          */
 518                         ret = 0;
 519                         goto end;
 520                 }
 521                 ust_reg = reg_pid->registry->reg.ust;
 522         }
 523         assert(ust_reg);
 524
 525         pthread_mutex_lock(&ust_reg->lock);
 526         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 527         pthread_mutex_unlock(&ust_reg->lock);
 528         if (ret_push == -EPIPE) {
 529                 DBG("Application or relay closed while pushing metadata");
 530         } else if (ret_push < 0) {
 531                 ERR("Pushing metadata");
 532                 ret = -1;
 533                 goto end;
 534         } else {
 535                 DBG("UST Consumer metadata pushed successfully");
 536         }
 537         ret = 0;
 538
 539 end:
 540         rcu_read_unlock();
 541         return ret;
 542 }