src/bin/lttng-sessiond/trace-kernel.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13
  14 #include <lttng/event.h>
  15 #include <lttng/lttng-error.h>
  16 #include <lttng/kernel-probe.h>
  17 #include <lttng/userspace-probe.h>
  18 #include <lttng/userspace-probe-internal.h>
  19 #include <lttng/event-rule/event-rule.h>
  20 #include <lttng/event-rule/event-rule-internal.h>
  21 #include <lttng/event-rule/kernel-probe.h>
  22 #include <lttng/event-rule/kernel-probe-internal.h>
  23 #include <lttng/event-rule/syscall.h>
  24 #include <lttng/event-rule/syscall-internal.h>
  25 #include <lttng/event-rule/tracepoint.h>
  26 #include <lttng/event-rule/tracepoint-internal.h>
  27 #include <lttng/event-rule/userspace-probe-internal.h>
  28 #include <common/common.h>
  29 #include <common/defaults.h>
  30 #include <common/trace-chunk.h>
  31 #include <common/macros.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_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_pid = process_attr_tracker_create();
 168         if (!lks->tracker_pid) {
 169                 goto error;
 170         }
 171         lks->tracker_vpid = process_attr_tracker_create();
 172         if (!lks->tracker_vpid) {
 173                 goto error;
 174         }
 175         lks->tracker_uid = process_attr_tracker_create();
 176         if (!lks->tracker_uid) {
 177                 goto error;
 178         }
 179         lks->tracker_vuid = process_attr_tracker_create();
 180         if (!lks->tracker_vuid) {
 181                 goto error;
 182         }
 183         lks->tracker_gid = process_attr_tracker_create();
 184         if (!lks->tracker_gid) {
 185                 goto error;
 186         }
 187         lks->tracker_vgid = process_attr_tracker_create();
 188         if (!lks->tracker_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         process_attr_tracker_destroy(lks->tracker_pid);
 200         process_attr_tracker_destroy(lks->tracker_vpid);
 201         process_attr_tracker_destroy(lks->tracker_uid);
 202         process_attr_tracker_destroy(lks->tracker_vuid);
 203         process_attr_tracker_destroy(lks->tracker_gid);
 204         process_attr_tracker_destroy(lks->tracker_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_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                 lookup = lttng_userspace_probe_location_get_lookup_method(
 382                                 location);
 383                 if (!lookup) {
 384                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 385                         goto error;
 386                 }
 387
 388                 /*
 389                  * From the kernel tracer's perspective, all userspace probe
 390                  * event types are all the same: a file and an offset.
 391                  */
 392                 switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
 393                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
 394                         /* Get the file descriptor on the target binary. */
 395                         attr->u.uprobe.fd =
 396                                         lttng_userspace_probe_location_function_get_binary_fd(location);
 397
 398                         /*
 399                          * Save a reference to the probe location used during
 400                          * the listing of events.
 401                          */
 402                         userspace_probe_location =
 403                                         lttng_userspace_probe_location_copy(location);
 404                         break;
 405                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
 406                         /* Get the file descriptor on the target binary. */
 407                         attr->u.uprobe.fd =
 408                                         lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
 409
 410                         /*
 411                          * Save a reference to the probe location used during the listing of
 412                          * events.
 413                          */
 414                         userspace_probe_location =
 415                                         lttng_userspace_probe_location_copy(location);
 416                         break;
 417                 default:
 418                         DBG("Unsupported lookup method type");
 419                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 420                         goto error;
 421                 }
 422                 break;
 423         }
 424         case LTTNG_EVENT_FUNCTION:
 425                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 426                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 427                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 428                 strncpy(attr->u.kretprobe.symbol_name,
 429                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 430                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 431                 break;
 432         case LTTNG_EVENT_FUNCTION_ENTRY:
 433                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 434                 strncpy(attr->u.ftrace.symbol_name,
 435                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 436                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 437                 break;
 438         case LTTNG_EVENT_TRACEPOINT:
 439                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 440                 break;
 441         case LTTNG_EVENT_SYSCALL:
 442                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 443                 attr->u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_ALL;
 444                 attr->u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_ENTRYEXIT;
 445                 attr->u.syscall.match = LTTNG_KERNEL_SYSCALL_MATCH_NAME;
 446                 break;
 447         case LTTNG_EVENT_ALL:
 448                 attr->instrumentation = LTTNG_KERNEL_ALL;
 449                 break;
 450         default:
 451                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 452                 ret = LTTNG_ERR_INVALID;
 453                 goto error;
 454         }
 455
 456         /* Copy event name */
 457         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 458         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 459
 460         /* Setting up a kernel event */
 461         local_kernel_event->fd = -1;
 462         local_kernel_event->event = attr;
 463         local_kernel_event->enabled = 1;
 464         local_kernel_event->filter_expression = filter_expression;
 465         local_kernel_event->filter = filter;
 466         local_kernel_event->userspace_probe_location = userspace_probe_location;
 467
 468         *kernel_event = local_kernel_event;
 469
 470         return LTTNG_OK;
 471
 472 error:
 473         free(filter_expression);
 474         free(filter);
 475         free(local_kernel_event);
 476         free(attr);
 477         return ret;
 478 }
 479
 480 /*
 481  * Allocate and initialize a kernel token event rule.
 482  *
 483  * Return pointer to structure or NULL.
 484  */
 485 enum lttng_error_code trace_kernel_create_event_notifier_rule(
 486                 struct lttng_trigger *trigger,
 487                 uint64_t token,
 488                 uint64_t error_counter_index,
 489                 struct ltt_kernel_event_notifier_rule **event_notifier_rule)
 490 {
 491         enum lttng_error_code ret = LTTNG_OK;
 492         enum lttng_condition_type condition_type;
 493         enum lttng_event_rule_type event_rule_type;
 494         enum lttng_condition_status condition_status;
 495         struct ltt_kernel_event_notifier_rule *local_kernel_token_event_rule;
 496         const struct lttng_condition *condition = NULL;
 497         const struct lttng_event_rule *event_rule = NULL;
 498
 499         assert(event_notifier_rule);
 500
 501         condition = lttng_trigger_get_const_condition(trigger);
 502         assert(condition);
 503
 504         condition_type = lttng_condition_get_type(condition);
 505         assert(condition_type == LTTNG_CONDITION_TYPE_ON_EVENT);
 506
 507         condition_status = lttng_condition_on_event_get_rule(
 508                         condition, &event_rule);
 509         assert(condition_status == LTTNG_CONDITION_STATUS_OK);
 510         assert(event_rule);
 511
 512         event_rule_type = lttng_event_rule_get_type(event_rule);
 513         assert(event_rule_type != LTTNG_EVENT_RULE_TYPE_UNKNOWN);
 514
 515         local_kernel_token_event_rule =
 516                         zmalloc(sizeof(struct ltt_kernel_event_notifier_rule));
 517         if (local_kernel_token_event_rule == NULL) {
 518                 PERROR("Failed to allocate ltt_kernel_token_event_rule structure");
 519                 ret = LTTNG_ERR_NOMEM;
 520                 goto error;
 521         }
 522
 523         local_kernel_token_event_rule->fd = -1;
 524         local_kernel_token_event_rule->enabled = 1;
 525         local_kernel_token_event_rule->token = token;
 526         local_kernel_token_event_rule->error_counter_index = error_counter_index;
 527
 528         /* Get the reference of the event rule. */
 529         lttng_trigger_get(trigger);
 530
 531         local_kernel_token_event_rule->trigger = trigger;
 532         /* The event rule still owns the filter and bytecode. */
 533         local_kernel_token_event_rule->filter =
 534                         lttng_event_rule_get_filter_bytecode(event_rule);
 535
 536         DBG3("Created kernel event notifier rule: token =  %" PRIu64,
 537                         local_kernel_token_event_rule->token);
 538 error:
 539         *event_notifier_rule = local_kernel_token_event_rule;
 540         return ret;
 541 }
 542
 543 /*
 544  * Initialize a kernel trigger from an event rule.
 545  */
 546 enum lttng_error_code trace_kernel_init_event_notifier_from_event_rule(
 547                 const struct lttng_event_rule *rule,
 548                 struct lttng_kernel_event_notifier *kernel_event_notifier)
 549 {
 550         enum lttng_error_code ret_code;
 551         const char *name;
 552         int strncpy_ret;
 553
 554         switch (lttng_event_rule_get_type(rule)) {
 555         case LTTNG_EVENT_RULE_TYPE_KERNEL_PROBE:
 556         {
 557                 uint64_t address = 0, offset = 0;
 558                 const char *symbol_name = NULL;
 559                 const struct lttng_kernel_probe_location *location = NULL;
 560                 enum lttng_kernel_probe_location_status k_status;
 561                 enum lttng_event_rule_status status;
 562
 563                 status = lttng_event_rule_kernel_probe_get_location(rule, &location);
 564                 if (status != LTTNG_EVENT_RULE_STATUS_OK) {
 565                         ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
 566                         goto error;
 567                 }
 568
 569                 switch (lttng_kernel_probe_location_get_type(location)) {
 570                 case LTTNG_KERNEL_PROBE_LOCATION_TYPE_ADDRESS:
 571                 {
 572                         k_status = lttng_kernel_probe_location_address_get_address(
 573                                         location, &address);
 574                         assert(k_status == LTTNG_KERNEL_PROBE_LOCATION_STATUS_OK);
 575                         break;
 576                 }
 577                 case LTTNG_KERNEL_PROBE_LOCATION_TYPE_SYMBOL_OFFSET:
 578                 {
 579                         k_status = lttng_kernel_probe_location_symbol_get_offset(
 580                                         location, &offset);
 581                         assert(k_status == LTTNG_KERNEL_PROBE_LOCATION_STATUS_OK);
 582                         symbol_name = lttng_kernel_probe_location_symbol_get_name(
 583                                         location);
 584                         break;
 585                 }
 586                 default:
 587                         abort();
 588                 }
 589
 590                 kernel_event_notifier->event.instrumentation = LTTNG_KERNEL_KPROBE;
 591                 kernel_event_notifier->event.u.kprobe.addr = address;
 592                 kernel_event_notifier->event.u.kprobe.offset = offset;
 593                 if (symbol_name) {
 594                         strncpy_ret = lttng_strncpy(
 595                                         kernel_event_notifier->event.u.kprobe.symbol_name,
 596                                         symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 597
 598                         if (strncpy_ret) {
 599                                 ret_code = LTTNG_ERR_INVALID;
 600                                 goto error;
 601                         }
 602                 }
 603
 604                 kernel_event_notifier->event.u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 605
 606                 status = lttng_event_rule_kernel_probe_get_event_name(rule, &name);
 607                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 608                 ret_code = LTTNG_OK;
 609                 break;
 610         }
 611         case LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE:
 612         {
 613                 const struct lttng_userspace_probe_location* location = NULL;
 614                 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
 615                 enum lttng_event_rule_status status;
 616
 617                 status = lttng_event_rule_userspace_probe_get_location(rule, &location);
 618                 if (status != LTTNG_EVENT_RULE_STATUS_OK) {
 619                         ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
 620                         goto error;
 621                 }
 622
 623                 kernel_event_notifier->event.instrumentation = LTTNG_KERNEL_UPROBE;
 624
 625                 lookup = lttng_userspace_probe_location_get_lookup_method(
 626                                 location);
 627                 if (!lookup) {
 628                         ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
 629                         goto error;
 630                 }
 631
 632                 /*
 633                  * From the kernel tracer's perspective, all userspace probe
 634                  * event types are all the same: a file and an offset.
 635                  */
 636                 switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
 637                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
 638                         /* Get the file descriptor on the target binary. */
 639                         kernel_event_notifier->event.u.uprobe.fd =
 640                                         lttng_userspace_probe_location_function_get_binary_fd(location);
 641
 642                         break;
 643                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
 644                         /* Get the file descriptor on the target binary. */
 645                         kernel_event_notifier->event.u.uprobe.fd =
 646                                         lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
 647                         break;
 648                 default:
 649                         abort();
 650                 }
 651
 652                 status = lttng_event_rule_userspace_probe_get_event_name(
 653                                 rule, &name);
 654                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 655                 ret_code = LTTNG_OK;
 656                 break;
 657         }
 658         case LTTNG_EVENT_RULE_TYPE_TRACEPOINT:
 659         {
 660                 const enum lttng_domain_type domain =
 661                                 lttng_event_rule_get_domain_type(rule);
 662                 const enum lttng_event_rule_status status =
 663                                 lttng_event_rule_tracepoint_get_pattern(
 664                                                 rule, &name);
 665
 666                 assert(domain == LTTNG_DOMAIN_KERNEL);
 667                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 668                 kernel_event_notifier->event.instrumentation =
 669                                 LTTNG_KERNEL_TRACEPOINT;
 670
 671                 ret_code = LTTNG_OK;
 672                 break;
 673         }
 674         case LTTNG_EVENT_RULE_TYPE_SYSCALL:
 675         {
 676                 const enum lttng_event_rule_status status =
 677                                 lttng_event_rule_syscall_get_pattern(
 678                                                 rule, &name);
 679
 680                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 681
 682                 kernel_event_notifier->event.instrumentation =
 683                                 LTTNG_KERNEL_SYSCALL;
 684                 kernel_event_notifier->event.u.syscall.abi =
 685                                 LTTNG_KERNEL_SYSCALL_ABI_ALL;
 686                 kernel_event_notifier->event.u.syscall.entryexit =
 687                                 LTTNG_KERNEL_SYSCALL_ENTRY;
 688                 kernel_event_notifier->event.u.syscall.match =
 689                                 LTTNG_KERNEL_SYSCALL_MATCH_NAME;
 690                 ret_code = LTTNG_OK;
 691                 break;
 692         }
 693         case LTTNG_EVENT_RULE_TYPE_KERNEL_FUNCTION:
 694         default:
 695                 abort();
 696                 break;
 697         }
 698
 699         strncpy_ret = lttng_strncpy(kernel_event_notifier->event.name, name,
 700                         LTTNG_KERNEL_SYM_NAME_LEN);
 701         if (strncpy_ret) {
 702                 ret_code = LTTNG_ERR_INVALID;
 703                 goto error;
 704         }
 705
 706 error:
 707         return ret_code;
 708 }
 709 /*
 710  * Allocate and initialize a kernel metadata.
 711  *
 712  * Return pointer to structure or NULL.
 713  */
 714 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 715 {
 716         int ret;
 717         struct ltt_kernel_metadata *lkm;
 718         struct lttng_channel *chan;
 719
 720         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 721         chan = zmalloc(sizeof(struct lttng_channel));
 722         if (lkm == NULL || chan == NULL) {
 723                 PERROR("kernel metadata zmalloc");
 724                 goto error;
 725         }
 726
 727         ret = lttng_strncpy(
 728                         chan->name, DEFAULT_METADATA_NAME, sizeof(chan->name));
 729         if (ret) {
 730                 ERR("Failed to initialize metadata channel name to `%s`",
 731                                 DEFAULT_METADATA_NAME);
 732                 goto error;
 733         }
 734
 735         /* Set default attributes */
 736         chan->attr.overwrite = DEFAULT_METADATA_OVERWRITE;
 737         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 738         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 739         chan->attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
 740         chan->attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;;
 741
 742
 743         /*
 744          * The metadata channel of kernel sessions must use the "mmap"
 745          * back-end since the consumer daemon accumulates complete
 746          * metadata units before sending them to the relay daemon in
 747          * live mode. The consumer daemon also needs to extract the contents
 748          * of the metadata cache when computing a rotation position.
 749          *
 750          * In both cases, it is not possible to rely on the splice
 751          * back-end as the consumer daemon may need to accumulate more
 752          * content than can be backed by the ring buffer's underlying
 753          * pages.
 754          */
 755         chan->attr.output = LTTNG_EVENT_MMAP;
 756         chan->attr.tracefile_size = 0;
 757         chan->attr.tracefile_count = 0;
 758         chan->attr.live_timer_interval = 0;
 759
 760         /* Init metadata */
 761         lkm->fd = -1;
 762         lkm->conf = chan;
 763
 764         return lkm;
 765
 766 error:
 767         free(lkm);
 768         free(chan);
 769         return NULL;
 770 }
 771
 772 /*
 773  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 774  * default.
 775  *
 776  * Return pointer to structure or NULL.
 777  */
 778 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 779                 unsigned int count)
 780 {
 781         int ret;
 782         struct ltt_kernel_stream *lks;
 783
 784         assert(name);
 785
 786         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 787         if (lks == NULL) {
 788                 PERROR("kernel stream zmalloc");
 789                 goto error;
 790         }
 791
 792         /* Set name */
 793         ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
 794         if (ret < 0) {
 795                 PERROR("snprintf stream name");
 796                 goto error;
 797         }
 798         lks->name[sizeof(lks->name) - 1] = '\0';
 799
 800         /* Init stream */
 801         lks->fd = -1;
 802         lks->state = 0;
 803         lks->cpu = count;
 804
 805         return lks;
 806
 807 error:
 808         return NULL;
 809 }
 810
 811 /*
 812  * Cleanup kernel stream structure.
 813  */
 814 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 815 {
 816         assert(stream);
 817
 818         DBG("[trace] Closing stream fd %d", stream->fd);
 819         /* Close kernel fd */
 820         if (stream->fd >= 0) {
 821                 int ret;
 822
 823                 ret = close(stream->fd);
 824                 if (ret) {
 825                         PERROR("close");
 826                 }
 827         }
 828         /* Remove from stream list */
 829         cds_list_del(&stream->list);
 830
 831         free(stream);
 832 }
 833
 834 /*
 835  * Cleanup kernel event structure.
 836  */
 837 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 838 {
 839         assert(event);
 840
 841         if (event->fd >= 0) {
 842                 int ret;
 843
 844                 DBG("[trace] Closing event fd %d", event->fd);
 845                 /* Close kernel fd */
 846                 ret = close(event->fd);
 847                 if (ret) {
 848                         PERROR("close");
 849                 }
 850         } else {
 851                 DBG("[trace] Tearing down event (no associated file descriptor)");
 852         }
 853
 854         /* Remove from event list */
 855         cds_list_del(&event->list);
 856
 857         free(event->filter_expression);
 858         free(event->filter);
 859
 860         free(event->event);
 861         free(event);
 862 }
 863
 864 /*
 865  * Cleanup kernel event structure.
 866  */
 867 static void free_token_event_rule_rcu(struct rcu_head *rcu_node)
 868 {
 869         struct ltt_kernel_event_notifier_rule *rule = caa_container_of(rcu_node,
 870                         struct ltt_kernel_event_notifier_rule, rcu_node);
 871
 872         free(rule);
 873 }
 874
 875 void trace_kernel_destroy_event_notifier_rule(
 876                 struct ltt_kernel_event_notifier_rule *event)
 877 {
 878         assert(event);
 879
 880         if (event->fd >= 0) {
 881                 const int ret = close(event->fd);
 882
 883                 DBG("Closing kernel event notifier rule file descriptor: fd = %d",
 884                                 event->fd);
 885                 if (ret) {
 886                         PERROR("Failed to close kernel event notifier file descriptor: fd = %d",
 887                                         event->fd);
 888                 }
 889         } else {
 890                 DBG("Destroying kernel event notifier rule (no associated file descriptor)");
 891         }
 892
 893         lttng_trigger_put(event->trigger);
 894         call_rcu(&event->rcu_node, free_token_event_rule_rcu);
 895 }
 896 /*
 897  * Cleanup kernel context structure.
 898  */
 899 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 900 {
 901         assert(ctx);
 902
 903         if (ctx->in_list) {
 904                 cds_list_del(&ctx->list);
 905         }
 906         free(ctx);
 907 }
 908
 909 /*
 910  * Cleanup kernel channel structure.
 911  */
 912 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 913 {
 914         struct ltt_kernel_stream *stream, *stmp;
 915         struct ltt_kernel_event *event, *etmp;
 916         struct ltt_kernel_context *ctx, *ctmp;
 917         int ret;
 918         enum lttng_error_code status;
 919
 920         assert(channel);
 921
 922         DBG("[trace] Closing channel fd %d", channel->fd);
 923         /* Close kernel fd */
 924         if (channel->fd >= 0) {
 925                 ret = close(channel->fd);
 926                 if (ret) {
 927                         PERROR("close");
 928                 }
 929         }
 930
 931         /* For each stream in the channel list */
 932         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 933                 trace_kernel_destroy_stream(stream);
 934         }
 935
 936         /* For each event in the channel list */
 937         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 938                 trace_kernel_destroy_event(event);
 939         }
 940
 941         /* For each context in the channel list */
 942         cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
 943                 trace_kernel_destroy_context(ctx);
 944         }
 945
 946         /* Remove from channel list */
 947         cds_list_del(&channel->list);
 948
 949         if (the_notification_thread_handle &&
 950                         channel->published_to_notification_thread) {
 951                 status = notification_thread_command_remove_channel(
 952                                 the_notification_thread_handle, channel->key,
 953                                 LTTNG_DOMAIN_KERNEL);
 954                 assert(status == LTTNG_OK);
 955         }
 956         free(channel->channel->attr.extended.ptr);
 957         free(channel->channel);
 958         free(channel);
 959 }
 960
 961 /*
 962  * Cleanup kernel metadata structure.
 963  */
 964 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 965 {
 966         assert(metadata);
 967
 968         DBG("[trace] Closing metadata fd %d", metadata->fd);
 969         /* Close kernel fd */
 970         if (metadata->fd >= 0) {
 971                 int ret;
 972
 973                 ret = close(metadata->fd);
 974                 if (ret) {
 975                         PERROR("close");
 976                 }
 977         }
 978
 979         free(metadata->conf);
 980         free(metadata);
 981 }
 982
 983 /*
 984  * Cleanup kernel session structure
 985  *
 986  * Should *NOT* be called with RCU read-side lock held.
 987  */
 988 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 989 {
 990         struct ltt_kernel_channel *channel, *ctmp;
 991         int ret;
 992
 993         assert(session);
 994
 995         DBG("[trace] Closing session fd %d", session->fd);
 996         /* Close kernel fds */
 997         if (session->fd >= 0) {
 998                 ret = close(session->fd);
 999                 if (ret) {
1000                         PERROR("close");
1001                 }
1002         }
1003
1004         if (session->metadata_stream_fd >= 0) {
1005                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
1006                 ret = close(session->metadata_stream_fd);
1007                 if (ret) {
1008                         PERROR("close");
1009                 }
1010         }
1011
1012         if (session->metadata != NULL) {
1013                 trace_kernel_destroy_metadata(session->metadata);
1014         }
1015
1016         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
1017                 trace_kernel_destroy_channel(channel);
1018         }
1019 }
1020
1021 /* Free elements needed by destroy notifiers. */
1022 void trace_kernel_free_session(struct ltt_kernel_session *session)
1023 {
1024         /* Wipe consumer output object */
1025         consumer_output_put(session->consumer);
1026
1027         process_attr_tracker_destroy(session->tracker_pid);
1028         process_attr_tracker_destroy(session->tracker_vpid);
1029         process_attr_tracker_destroy(session->tracker_uid);
1030         process_attr_tracker_destroy(session->tracker_vuid);
1031         process_attr_tracker_destroy(session->tracker_gid);
1032         process_attr_tracker_destroy(session->tracker_vgid);
1033
1034         free(session);
1035 }