src/bin/lttng-sessiond/trace-kernel.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 <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 #include <lttng/event.h>
  25 #include <lttng/lttng-error.h>
  26 #include <lttng/userspace-probe.h>
  27 #include <lttng/userspace-probe-internal.h>
  28
  29 #include <common/common.h>
  30 #include <common/defaults.h>
  31 #include <common/trace-chunk.h>
  32
  33 #include "consumer.h"
  34 #include "trace-kernel.h"
  35 #include "lttng-sessiond.h"
  36 #include "notification-thread-commands.h"
  37
  38 /*
  39  * Find the channel name for the given kernel session.
  40  */
  41 struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
  42                 const char *name, struct ltt_kernel_session *session)
  43 {
  44         struct ltt_kernel_channel *chan;
  45
  46         assert(session);
  47         assert(name);
  48
  49         /*
  50          * If we receive an empty string for channel name, it means the
  51          * default channel name is requested.
  52          */
  53         if (name[0] == '\0')
  54                 name = DEFAULT_CHANNEL_NAME;
  55
  56         DBG("Trying to find channel %s", name);
  57
  58         cds_list_for_each_entry(chan, &session->channel_list.head, list) {
  59                 if (strcmp(name, chan->channel->name) == 0) {
  60                         DBG("Found channel by name %s", name);
  61                         return chan;
  62                 }
  63         }
  64
  65         return NULL;
  66 }
  67
  68 /*
  69  * Find the event for the given channel.
  70  */
  71 struct ltt_kernel_event *trace_kernel_find_event(
  72                 char *name, struct ltt_kernel_channel *channel,
  73                 enum lttng_event_type type,
  74                 struct lttng_filter_bytecode *filter)
  75 {
  76         struct ltt_kernel_event *ev;
  77         int found = 0;
  78
  79         assert(name);
  80         assert(channel);
  81
  82         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
  83                 if (type != LTTNG_EVENT_ALL && ev->type != type) {
  84                         continue;
  85                 }
  86                 if (strcmp(name, ev->event->name)) {
  87                         continue;
  88                 }
  89                 if ((ev->filter && !filter) || (!ev->filter && filter)) {
  90                         continue;
  91                 }
  92                 if (ev->filter && filter) {
  93                         if (ev->filter->len != filter->len ||
  94                                         memcmp(ev->filter->data, filter->data,
  95                                                 filter->len) != 0) {
  96                                 continue;
  97                         }
  98                 }
  99                 found = 1;
 100                 break;
 101         }
 102         if (found) {
 103                 DBG("Found event %s for channel %s", name,
 104                         channel->channel->name);
 105                 return ev;
 106         } else {
 107                 return NULL;
 108         }
 109 }
 110
 111 /*
 112  * Find the event name for the given channel.
 113  */
 114 struct ltt_kernel_event *trace_kernel_get_event_by_name(
 115                 char *name, struct ltt_kernel_channel *channel,
 116                 enum lttng_event_type type)
 117 {
 118         struct ltt_kernel_event *ev;
 119         int found = 0;
 120
 121         assert(name);
 122         assert(channel);
 123
 124         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
 125                 if (type != LTTNG_EVENT_ALL && ev->type != type) {
 126                         continue;
 127                 }
 128                 if (strcmp(name, ev->event->name)) {
 129                         continue;
 130                 }
 131                 found = 1;
 132                 break;
 133         }
 134         if (found) {
 135                 DBG("Found event %s for channel %s", name,
 136                         channel->channel->name);
 137                 return ev;
 138         } else {
 139                 return NULL;
 140         }
 141 }
 142
 143 /*
 144  * Allocate and initialize a kernel session data structure.
 145  *
 146  * Return pointer to structure or NULL.
 147  */
 148 struct ltt_kernel_session *trace_kernel_create_session(void)
 149 {
 150         struct ltt_kernel_session *lks = NULL;
 151
 152         /* Allocate a new ltt kernel session */
 153         lks = zmalloc(sizeof(struct ltt_kernel_session));
 154         if (lks == NULL) {
 155                 PERROR("create kernel session zmalloc");
 156                 goto alloc_error;
 157         }
 158
 159         /* Init data structure */
 160         lks->fd = -1;
 161         lks->metadata_stream_fd = -1;
 162         lks->channel_count = 0;
 163         lks->stream_count_global = 0;
 164         lks->metadata = NULL;
 165         CDS_INIT_LIST_HEAD(&lks->channel_list.head);
 166
 167         lks->tracker_list_pid = lttng_tracker_list_create();
 168         if (!lks->tracker_list_pid) {
 169                 goto error;
 170         }
 171         lks->tracker_list_vpid = lttng_tracker_list_create();
 172         if (!lks->tracker_list_vpid) {
 173                 goto error;
 174         }
 175         lks->tracker_list_uid = lttng_tracker_list_create();
 176         if (!lks->tracker_list_uid) {
 177                 goto error;
 178         }
 179         lks->tracker_list_vuid = lttng_tracker_list_create();
 180         if (!lks->tracker_list_vuid) {
 181                 goto error;
 182         }
 183         lks->tracker_list_gid = lttng_tracker_list_create();
 184         if (!lks->tracker_list_gid) {
 185                 goto error;
 186         }
 187         lks->tracker_list_vgid = lttng_tracker_list_create();
 188         if (!lks->tracker_list_vgid) {
 189                 goto error;
 190         }
 191         lks->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 192         if (lks->consumer == NULL) {
 193                 goto error;
 194         }
 195
 196         return lks;
 197
 198 error:
 199         lttng_tracker_list_destroy(lks->tracker_list_pid);
 200         lttng_tracker_list_destroy(lks->tracker_list_vpid);
 201         lttng_tracker_list_destroy(lks->tracker_list_uid);
 202         lttng_tracker_list_destroy(lks->tracker_list_vuid);
 203         lttng_tracker_list_destroy(lks->tracker_list_gid);
 204         lttng_tracker_list_destroy(lks->tracker_list_vgid);
 205         free(lks);
 206
 207 alloc_error:
 208         return NULL;
 209 }
 210
 211 /*
 212  * Allocate and initialize a kernel channel data structure.
 213  *
 214  * Return pointer to structure or NULL.
 215  */
 216 struct ltt_kernel_channel *trace_kernel_create_channel(
 217                 struct lttng_channel *chan)
 218 {
 219         struct ltt_kernel_channel *lkc;
 220         struct lttng_channel_extended *extended = NULL;
 221
 222         assert(chan);
 223
 224         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 225         if (lkc == NULL) {
 226                 PERROR("ltt_kernel_channel zmalloc");
 227                 goto error;
 228         }
 229
 230         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 231         if (lkc->channel == NULL) {
 232                 PERROR("lttng_channel zmalloc");
 233                 goto error;
 234         }
 235
 236         extended = zmalloc(sizeof(struct lttng_channel_extended));
 237         if (!extended) {
 238                 PERROR("lttng_channel_channel zmalloc");
 239                 goto error;
 240         }
 241         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 242         memcpy(extended, chan->attr.extended.ptr, sizeof(struct lttng_channel_extended));
 243         lkc->channel->attr.extended.ptr = extended;
 244         extended = NULL;
 245
 246         /*
 247          * If we receive an empty string for channel name, it means the
 248          * default channel name is requested.
 249          */
 250         if (chan->name[0] == '\0') {
 251                 strncpy(lkc->channel->name, DEFAULT_CHANNEL_NAME,
 252                         sizeof(lkc->channel->name));
 253         }
 254         lkc->channel->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 255
 256         lkc->fd = -1;
 257         lkc->stream_count = 0;
 258         lkc->event_count = 0;
 259         lkc->enabled = 1;
 260         lkc->published_to_notification_thread = false;
 261         /* Init linked list */
 262         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 263         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 264         CDS_INIT_LIST_HEAD(&lkc->ctx_list);
 265
 266         return lkc;
 267
 268 error:
 269         if (lkc) {
 270                 free(lkc->channel);
 271         }
 272         free(extended);
 273         free(lkc);
 274         return NULL;
 275 }
 276
 277 /*
 278  * Allocate and init a kernel context object.
 279  *
 280  * Return the allocated object or NULL on error.
 281  */
 282 struct ltt_kernel_context *trace_kernel_create_context(
 283                 struct lttng_kernel_context *ctx)
 284 {
 285         struct ltt_kernel_context *kctx;
 286
 287         kctx = zmalloc(sizeof(*kctx));
 288         if (!kctx) {
 289                 PERROR("zmalloc kernel context");
 290                 goto error;
 291         }
 292
 293         if (ctx) {
 294                 memcpy(&kctx->ctx, ctx, sizeof(kctx->ctx));
 295         }
 296 error:
 297         return kctx;
 298 }
 299
 300 /*
 301  * Allocate and init a kernel context object from an existing kernel context
 302  * object.
 303  *
 304  * Return the allocated object or NULL on error.
 305  */
 306 struct ltt_kernel_context *trace_kernel_copy_context(
 307                 struct ltt_kernel_context *kctx)
 308 {
 309         struct ltt_kernel_context *kctx_copy;
 310
 311         assert(kctx);
 312         kctx_copy = zmalloc(sizeof(*kctx_copy));
 313         if (!kctx_copy) {
 314                 PERROR("zmalloc ltt_kernel_context");
 315                 goto error;
 316         }
 317
 318         memcpy(kctx_copy, kctx, sizeof(*kctx_copy));
 319         memset(&kctx_copy->list, 0, sizeof(kctx_copy->list));
 320
 321 error:
 322         return kctx_copy;
 323 }
 324
 325 /*
 326  * Allocate and initialize a kernel event. Set name and event type.
 327  * We own filter_expression, and filter.
 328  *
 329  * Return pointer to structure or NULL.
 330  */
 331 enum lttng_error_code trace_kernel_create_event(
 332                 struct lttng_event *ev, char *filter_expression,
 333                 struct lttng_filter_bytecode *filter,
 334                 struct ltt_kernel_event **kernel_event)
 335 {
 336         enum lttng_error_code ret;
 337         struct lttng_kernel_event *attr;
 338         struct ltt_kernel_event *local_kernel_event;
 339         struct lttng_userspace_probe_location *userspace_probe_location = NULL;
 340
 341         assert(ev);
 342
 343         local_kernel_event = zmalloc(sizeof(struct ltt_kernel_event));
 344         attr = zmalloc(sizeof(struct lttng_kernel_event));
 345         if (local_kernel_event == NULL || attr == NULL) {
 346                 PERROR("kernel event zmalloc");
 347                 ret = LTTNG_ERR_NOMEM;
 348                 goto error;
 349         }
 350
 351         switch (ev->type) {
 352         case LTTNG_EVENT_PROBE:
 353                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 354                 attr->u.kprobe.addr = ev->attr.probe.addr;
 355                 attr->u.kprobe.offset = ev->attr.probe.offset;
 356                 strncpy(attr->u.kprobe.symbol_name,
 357                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 358                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 359                 break;
 360         case LTTNG_EVENT_USERSPACE_PROBE:
 361         {
 362                 const struct lttng_userspace_probe_location* location = NULL;
 363                 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
 364
 365                 location = lttng_event_get_userspace_probe_location(ev);
 366                 if (!location) {
 367                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 368                         goto error;
 369                 }
 370
 371                 /*
 372                  * From this point on, the specific term 'uprobe' is used
 373                  * instead of the generic 'userspace probe' because it's the
 374                  * technology used at the moment for this instrumentation.
 375                  * LTTng currently implements userspace probes using uprobes.
 376                  * In the interactions with the kernel tracer, we use the
 377                  * uprobe term.
 378                  */
 379                 attr->instrumentation = LTTNG_KERNEL_UPROBE;
 380
 381                 /*
 382                  * Only the elf lookup method is supported at the moment.
 383                  */
 384                 lookup = lttng_userspace_probe_location_get_lookup_method(
 385                                 location);
 386                 if (!lookup) {
 387                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 388                         goto error;
 389                 }
 390
 391                 /*
 392                  * From the kernel tracer's perspective, all userspace probe
 393                  * event types are all the same: a file and an offset.
 394                  */
 395                 switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
 396                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
 397                         /* Get the file descriptor on the target binary. */
 398                         attr->u.uprobe.fd =
 399                                         lttng_userspace_probe_location_function_get_binary_fd(location);
 400
 401                         /*
 402                          * Save a reference to the probe location used during
 403                          * the listing of events. Close its FD since it won't
 404                          * be needed for listing.
 405                          */
 406                         userspace_probe_location =
 407                                         lttng_userspace_probe_location_copy(location);
 408                         ret = lttng_userspace_probe_location_function_set_binary_fd(
 409                                         userspace_probe_location, -1);
 410                         if (ret) {
 411                                 goto error;
 412                         }
 413                         break;
 414                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
 415                         /* Get the file descriptor on the target binary. */
 416                         attr->u.uprobe.fd =
 417                                         lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
 418
 419                         /*
 420                          * Save a reference to the probe location used during the listing of
 421                          * events. Close its FD since it won't be needed for listing.
 422                          */
 423                         userspace_probe_location =
 424                                         lttng_userspace_probe_location_copy(location);
 425                         ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
 426                                         userspace_probe_location, -1);
 427                         if (ret) {
 428                                 goto error;
 429                         }
 430                         break;
 431                 default:
 432                         DBG("Unsupported lookup method type");
 433                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 434                         goto error;
 435                 }
 436                 break;
 437         }
 438         case LTTNG_EVENT_FUNCTION:
 439                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 440                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 441                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 442                 strncpy(attr->u.kretprobe.symbol_name,
 443                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 444                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 445                 break;
 446         case LTTNG_EVENT_FUNCTION_ENTRY:
 447                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 448                 strncpy(attr->u.ftrace.symbol_name,
 449                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 450                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 451                 break;
 452         case LTTNG_EVENT_TRACEPOINT:
 453                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 454                 break;
 455         case LTTNG_EVENT_SYSCALL:
 456                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 457                 break;
 458         case LTTNG_EVENT_ALL:
 459                 attr->instrumentation = LTTNG_KERNEL_ALL;
 460                 break;
 461         default:
 462                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 463                 ret = LTTNG_ERR_INVALID;
 464                 goto error;
 465         }
 466
 467         /* Copy event name */
 468         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 469         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 470
 471         /* Setting up a kernel event */
 472         local_kernel_event->fd = -1;
 473         local_kernel_event->event = attr;
 474         local_kernel_event->enabled = 1;
 475         local_kernel_event->filter_expression = filter_expression;
 476         local_kernel_event->filter = filter;
 477         local_kernel_event->userspace_probe_location = userspace_probe_location;
 478
 479         *kernel_event = local_kernel_event;
 480
 481         return LTTNG_OK;
 482
 483 error:
 484         free(filter_expression);
 485         free(filter);
 486         free(local_kernel_event);
 487         free(attr);
 488         return ret;
 489 }
 490
 491 /*
 492  * Allocate and initialize a kernel metadata.
 493  *
 494  * Return pointer to structure or NULL.
 495  */
 496 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 497 {
 498         struct ltt_kernel_metadata *lkm;
 499         struct lttng_channel *chan;
 500
 501         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 502         chan = zmalloc(sizeof(struct lttng_channel));
 503         if (lkm == NULL || chan == NULL) {
 504                 PERROR("kernel metadata zmalloc");
 505                 goto error;
 506         }
 507
 508         /* Set default attributes */
 509         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 510         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 511         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 512         chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
 513         chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
 514         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 515
 516         /* Init metadata */
 517         lkm->fd = -1;
 518         lkm->conf = chan;
 519
 520         return lkm;
 521
 522 error:
 523         free(lkm);
 524         free(chan);
 525         return NULL;
 526 }
 527
 528 /*
 529  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 530  * default.
 531  *
 532  * Return pointer to structure or NULL.
 533  */
 534 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 535                 unsigned int count)
 536 {
 537         int ret;
 538         struct ltt_kernel_stream *lks;
 539
 540         assert(name);
 541
 542         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 543         if (lks == NULL) {
 544                 PERROR("kernel stream zmalloc");
 545                 goto error;
 546         }
 547
 548         /* Set name */
 549         ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
 550         if (ret < 0) {
 551                 PERROR("snprintf stream name");
 552                 goto error;
 553         }
 554         lks->name[sizeof(lks->name) - 1] = '\0';
 555
 556         /* Init stream */
 557         lks->fd = -1;
 558         lks->state = 0;
 559         lks->cpu = count;
 560
 561         return lks;
 562
 563 error:
 564         return NULL;
 565 }
 566
 567 /*
 568  * Cleanup kernel stream structure.
 569  */
 570 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 571 {
 572         assert(stream);
 573
 574         DBG("[trace] Closing stream fd %d", stream->fd);
 575         /* Close kernel fd */
 576         if (stream->fd >= 0) {
 577                 int ret;
 578
 579                 ret = close(stream->fd);
 580                 if (ret) {
 581                         PERROR("close");
 582                 }
 583         }
 584         /* Remove from stream list */
 585         cds_list_del(&stream->list);
 586
 587         free(stream);
 588 }
 589
 590 /*
 591  * Cleanup kernel event structure.
 592  */
 593 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 594 {
 595         assert(event);
 596
 597         if (event->fd >= 0) {
 598                 int ret;
 599
 600                 DBG("[trace] Closing event fd %d", event->fd);
 601                 /* Close kernel fd */
 602                 ret = close(event->fd);
 603                 if (ret) {
 604                         PERROR("close");
 605                 }
 606         } else {
 607                 DBG("[trace] Tearing down event (no associated fd)");
 608         }
 609
 610         /* Remove from event list */
 611         cds_list_del(&event->list);
 612
 613         free(event->filter_expression);
 614         free(event->filter);
 615
 616         free(event->event);
 617         free(event);
 618 }
 619
 620 /*
 621  * Cleanup kernel context structure.
 622  */
 623 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 624 {
 625         assert(ctx);
 626
 627         if (ctx->in_list) {
 628                 cds_list_del(&ctx->list);
 629         }
 630         free(ctx);
 631 }
 632
 633 /*
 634  * Cleanup kernel channel structure.
 635  */
 636 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 637 {
 638         struct ltt_kernel_stream *stream, *stmp;
 639         struct ltt_kernel_event *event, *etmp;
 640         struct ltt_kernel_context *ctx, *ctmp;
 641         int ret;
 642         enum lttng_error_code status;
 643
 644         assert(channel);
 645
 646         DBG("[trace] Closing channel fd %d", channel->fd);
 647         /* Close kernel fd */
 648         if (channel->fd >= 0) {
 649                 ret = close(channel->fd);
 650                 if (ret) {
 651                         PERROR("close");
 652                 }
 653         }
 654
 655         /* For each stream in the channel list */
 656         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 657                 trace_kernel_destroy_stream(stream);
 658         }
 659
 660         /* For each event in the channel list */
 661         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 662                 trace_kernel_destroy_event(event);
 663         }
 664
 665         /* For each context in the channel list */
 666         cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
 667                 trace_kernel_destroy_context(ctx);
 668         }
 669
 670         /* Remove from channel list */
 671         cds_list_del(&channel->list);
 672
 673         if (notification_thread_handle
 674                         && channel->published_to_notification_thread) {
 675                 status = notification_thread_command_remove_channel(
 676                                 notification_thread_handle,
 677                                 channel->key, LTTNG_DOMAIN_KERNEL);
 678                 assert(status == LTTNG_OK);
 679         }
 680         free(channel->channel->attr.extended.ptr);
 681         free(channel->channel);
 682         free(channel);
 683 }
 684
 685 /*
 686  * Cleanup kernel metadata structure.
 687  */
 688 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 689 {
 690         assert(metadata);
 691
 692         DBG("[trace] Closing metadata fd %d", metadata->fd);
 693         /* Close kernel fd */
 694         if (metadata->fd >= 0) {
 695                 int ret;
 696
 697                 ret = close(metadata->fd);
 698                 if (ret) {
 699                         PERROR("close");
 700                 }
 701         }
 702
 703         free(metadata->conf);
 704         free(metadata);
 705 }
 706
 707 /*
 708  * Cleanup kernel session structure
 709  *
 710  * Should *NOT* be called with RCU read-side lock held.
 711  */
 712 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 713 {
 714         struct ltt_kernel_channel *channel, *ctmp;
 715         int ret;
 716
 717         assert(session);
 718
 719         DBG("[trace] Closing session fd %d", session->fd);
 720         /* Close kernel fds */
 721         if (session->fd >= 0) {
 722                 ret = close(session->fd);
 723                 if (ret) {
 724                         PERROR("close");
 725                 }
 726         }
 727
 728         if (session->metadata_stream_fd >= 0) {
 729                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 730                 ret = close(session->metadata_stream_fd);
 731                 if (ret) {
 732                         PERROR("close");
 733                 }
 734         }
 735
 736         if (session->metadata != NULL) {
 737                 trace_kernel_destroy_metadata(session->metadata);
 738         }
 739
 740         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 741                 trace_kernel_destroy_channel(channel);
 742         }
 743 }
 744
 745 /* Free elements needed by destroy notifiers. */
 746 void trace_kernel_free_session(struct ltt_kernel_session *session)
 747 {
 748         /* Wipe consumer output object */
 749         consumer_output_put(session->consumer);
 750
 751         lttng_tracker_list_destroy(session->tracker_list_pid);
 752         lttng_tracker_list_destroy(session->tracker_list_vpid);
 753         lttng_tracker_list_destroy(session->tracker_list_uid);
 754         lttng_tracker_list_destroy(session->tracker_list_vuid);
 755         lttng_tracker_list_destroy(session->tracker_list_gid);
 756         lttng_tracker_list_destroy(session->tracker_list_vgid);
 757
 758         free(session);
 759 }