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                 struct ltt_kernel_event_notifier_rule **event_notifier_rule)
 489 {
 490         enum lttng_error_code ret = LTTNG_OK;
 491         enum lttng_condition_type condition_type;
 492         enum lttng_event_rule_type event_rule_type;
 493         enum lttng_condition_status condition_status;
 494         struct ltt_kernel_event_notifier_rule *local_kernel_token_event_rule;
 495         const struct lttng_condition *condition = NULL;
 496         const struct lttng_event_rule *event_rule = NULL;
 497
 498         assert(event_notifier_rule);
 499
 500         condition = lttng_trigger_get_condition(trigger);
 501         assert(condition);
 502
 503         condition_type = lttng_condition_get_type(condition);
 504         assert(condition_type == LTTNG_CONDITION_TYPE_ON_EVENT);
 505
 506         condition_status = lttng_condition_on_event_get_rule(
 507                         condition, &event_rule);
 508         assert(condition_status == LTTNG_CONDITION_STATUS_OK);
 509         assert(event_rule);
 510
 511         event_rule_type = lttng_event_rule_get_type(event_rule);
 512         assert(event_rule_type != LTTNG_EVENT_RULE_TYPE_UNKNOWN);
 513
 514         local_kernel_token_event_rule =
 515                         zmalloc(sizeof(struct ltt_kernel_event_notifier_rule));
 516         if (local_kernel_token_event_rule == NULL) {
 517                 PERROR("Failed to allocate ltt_kernel_token_event_rule structure");
 518                 ret = LTTNG_ERR_NOMEM;
 519                 goto error;
 520         }
 521
 522         local_kernel_token_event_rule->fd = -1;
 523         local_kernel_token_event_rule->enabled = 1;
 524         local_kernel_token_event_rule->token = token;
 525
 526         /* Get the reference of the event rule. */
 527         lttng_trigger_get(trigger);
 528
 529         local_kernel_token_event_rule->trigger = trigger;
 530         /* The event rule still owns the filter and bytecode. */
 531         local_kernel_token_event_rule->filter =
 532                         lttng_event_rule_get_filter_bytecode(event_rule);
 533
 534         DBG3("Created kernel event notifier rule: token =  %" PRIu64,
 535                         local_kernel_token_event_rule->token);
 536 error:
 537         *event_notifier_rule = local_kernel_token_event_rule;
 538         return ret;
 539 }
 540
 541 /*
 542  * Initialize a kernel trigger from an event rule.
 543  */
 544 enum lttng_error_code trace_kernel_init_event_notifier_from_event_rule(
 545                 const struct lttng_event_rule *rule,
 546                 struct lttng_kernel_event_notifier *kernel_event_notifier)
 547 {
 548         enum lttng_error_code ret_code;
 549         const char *name;
 550         int strncpy_ret;
 551
 552         switch (lttng_event_rule_get_type(rule)) {
 553         case LTTNG_EVENT_RULE_TYPE_KERNEL_PROBE:
 554         {
 555                 uint64_t address = 0, offset = 0;
 556                 const char *symbol_name = NULL;
 557                 const struct lttng_kernel_probe_location *location = NULL;
 558                 enum lttng_kernel_probe_location_status k_status;
 559                 enum lttng_event_rule_status status;
 560
 561                 status = lttng_event_rule_kernel_probe_get_location(rule, &location);
 562                 if (status != LTTNG_EVENT_RULE_STATUS_OK) {
 563                         ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
 564                         goto error;
 565                 }
 566
 567                 switch (lttng_kernel_probe_location_get_type(location)) {
 568                 case LTTNG_KERNEL_PROBE_LOCATION_TYPE_ADDRESS:
 569                 {
 570                         k_status = lttng_kernel_probe_location_address_get_address(
 571                                         location, &address);
 572                         assert(k_status == LTTNG_KERNEL_PROBE_LOCATION_STATUS_OK);
 573                         break;
 574                 }
 575                 case LTTNG_KERNEL_PROBE_LOCATION_TYPE_SYMBOL_OFFSET:
 576                 {
 577                         k_status = lttng_kernel_probe_location_symbol_get_offset(
 578                                         location, &offset);
 579                         assert(k_status == LTTNG_KERNEL_PROBE_LOCATION_STATUS_OK);
 580                         symbol_name = lttng_kernel_probe_location_symbol_get_name(
 581                                         location);
 582                         break;
 583                 }
 584                 default:
 585                         abort();
 586                 }
 587
 588                 kernel_event_notifier->event.instrumentation = LTTNG_KERNEL_KPROBE;
 589                 kernel_event_notifier->event.u.kprobe.addr = address;
 590                 kernel_event_notifier->event.u.kprobe.offset = offset;
 591                 if (symbol_name) {
 592                         strncpy_ret = lttng_strncpy(
 593                                         kernel_event_notifier->event.u.kprobe.symbol_name,
 594                                         symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 595
 596                         if (strncpy_ret) {
 597                                 ret_code = LTTNG_ERR_INVALID;
 598                                 goto error;
 599                         }
 600                 }
 601
 602                 kernel_event_notifier->event.u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 603
 604                 status = lttng_event_rule_kernel_probe_get_event_name(rule, &name);
 605                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 606                 ret_code = LTTNG_OK;
 607                 break;
 608         }
 609         case LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE:
 610         {
 611                 const struct lttng_userspace_probe_location* location = NULL;
 612                 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
 613                 enum lttng_event_rule_status status;
 614
 615                 status = lttng_event_rule_userspace_probe_get_location(rule, &location);
 616                 if (status != LTTNG_EVENT_RULE_STATUS_OK) {
 617                         ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
 618                         goto error;
 619                 }
 620
 621                 kernel_event_notifier->event.instrumentation = LTTNG_KERNEL_UPROBE;
 622
 623                 lookup = lttng_userspace_probe_location_get_lookup_method(
 624                                 location);
 625                 if (!lookup) {
 626                         ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
 627                         goto error;
 628                 }
 629
 630                 /*
 631                  * From the kernel tracer's perspective, all userspace probe
 632                  * event types are all the same: a file and an offset.
 633                  */
 634                 switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
 635                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
 636                         /* Get the file descriptor on the target binary. */
 637                         kernel_event_notifier->event.u.uprobe.fd =
 638                                         lttng_userspace_probe_location_function_get_binary_fd(location);
 639
 640                         break;
 641                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
 642                         /* Get the file descriptor on the target binary. */
 643                         kernel_event_notifier->event.u.uprobe.fd =
 644                                         lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
 645                         break;
 646                 default:
 647                         abort();
 648                 }
 649
 650                 status = lttng_event_rule_userspace_probe_get_name(rule, &name);
 651                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 652                 ret_code = LTTNG_OK;
 653                 break;
 654         }
 655         case LTTNG_EVENT_RULE_TYPE_TRACEPOINT:
 656         {
 657                 const enum lttng_domain_type domain =
 658                                 lttng_event_rule_get_domain_type(rule);
 659                 const enum lttng_event_rule_status status =
 660                                 lttng_event_rule_tracepoint_get_pattern(
 661                                                 rule, &name);
 662
 663                 assert(domain == LTTNG_DOMAIN_KERNEL);
 664                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 665                 kernel_event_notifier->event.instrumentation =
 666                                 LTTNG_KERNEL_TRACEPOINT;
 667
 668                 ret_code = LTTNG_OK;
 669                 break;
 670         }
 671         case LTTNG_EVENT_RULE_TYPE_SYSCALL:
 672         {
 673                 const enum lttng_event_rule_status status =
 674                                 lttng_event_rule_syscall_get_pattern(
 675                                                 rule, &name);
 676
 677                 assert(status == LTTNG_EVENT_RULE_STATUS_OK);
 678
 679                 kernel_event_notifier->event.instrumentation =
 680                                 LTTNG_KERNEL_SYSCALL;
 681                 kernel_event_notifier->event.u.syscall.abi =
 682                                 LTTNG_KERNEL_SYSCALL_ABI_ALL;
 683                 kernel_event_notifier->event.u.syscall.entryexit =
 684                                 LTTNG_KERNEL_SYSCALL_ENTRY;
 685                 kernel_event_notifier->event.u.syscall.match =
 686                                 LTTNG_KERNEL_SYSCALL_MATCH_NAME;
 687                 ret_code = LTTNG_OK;
 688                 break;
 689         }
 690         case LTTNG_EVENT_RULE_TYPE_KRETPROBE:
 691         default:
 692                 abort();
 693                 break;
 694         }
 695
 696         strncpy_ret = lttng_strncpy(kernel_event_notifier->event.name, name,
 697                         LTTNG_KERNEL_SYM_NAME_LEN);
 698         if (strncpy_ret) {
 699                 ret_code = LTTNG_ERR_INVALID;
 700                 goto error;
 701         }
 702
 703 error:
 704         return ret_code;
 705 }
 706 /*
 707  * Allocate and initialize a kernel metadata.
 708  *
 709  * Return pointer to structure or NULL.
 710  */
 711 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 712 {
 713         int ret;
 714         struct ltt_kernel_metadata *lkm;
 715         struct lttng_channel *chan;
 716
 717         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 718         chan = zmalloc(sizeof(struct lttng_channel));
 719         if (lkm == NULL || chan == NULL) {
 720                 PERROR("kernel metadata zmalloc");
 721                 goto error;
 722         }
 723
 724         ret = lttng_strncpy(
 725                         chan->name, DEFAULT_METADATA_NAME, sizeof(chan->name));
 726         if (ret) {
 727                 ERR("Failed to initialize metadata channel name to `%s`",
 728                                 DEFAULT_METADATA_NAME);
 729                 goto error;
 730         }
 731
 732         /* Set default attributes */
 733         chan->attr.overwrite = DEFAULT_METADATA_OVERWRITE;
 734         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 735         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 736         chan->attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
 737         chan->attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;;
 738
 739
 740         /*
 741          * The metadata channel of kernel sessions must use the "mmap"
 742          * back-end since the consumer daemon accumulates complete
 743          * metadata units before sending them to the relay daemon in
 744          * live mode. The consumer daemon also needs to extract the contents
 745          * of the metadata cache when computing a rotation position.
 746          *
 747          * In both cases, it is not possible to rely on the splice
 748          * back-end as the consumer daemon may need to accumulate more
 749          * content than can be backed by the ring buffer's underlying
 750          * pages.
 751          */
 752         chan->attr.output = LTTNG_EVENT_MMAP;
 753         chan->attr.tracefile_size = 0;
 754         chan->attr.tracefile_count = 0;
 755         chan->attr.live_timer_interval = 0;
 756
 757         /* Init metadata */
 758         lkm->fd = -1;
 759         lkm->conf = chan;
 760
 761         return lkm;
 762
 763 error:
 764         free(lkm);
 765         free(chan);
 766         return NULL;
 767 }
 768
 769 /*
 770  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 771  * default.
 772  *
 773  * Return pointer to structure or NULL.
 774  */
 775 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 776                 unsigned int count)
 777 {
 778         int ret;
 779         struct ltt_kernel_stream *lks;
 780
 781         assert(name);
 782
 783         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 784         if (lks == NULL) {
 785                 PERROR("kernel stream zmalloc");
 786                 goto error;
 787         }
 788
 789         /* Set name */
 790         ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
 791         if (ret < 0) {
 792                 PERROR("snprintf stream name");
 793                 goto error;
 794         }
 795         lks->name[sizeof(lks->name) - 1] = '\0';
 796
 797         /* Init stream */
 798         lks->fd = -1;
 799         lks->state = 0;
 800         lks->cpu = count;
 801
 802         return lks;
 803
 804 error:
 805         return NULL;
 806 }
 807
 808 /*
 809  * Cleanup kernel stream structure.
 810  */
 811 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 812 {
 813         assert(stream);
 814
 815         DBG("[trace] Closing stream fd %d", stream->fd);
 816         /* Close kernel fd */
 817         if (stream->fd >= 0) {
 818                 int ret;
 819
 820                 ret = close(stream->fd);
 821                 if (ret) {
 822                         PERROR("close");
 823                 }
 824         }
 825         /* Remove from stream list */
 826         cds_list_del(&stream->list);
 827
 828         free(stream);
 829 }
 830
 831 /*
 832  * Cleanup kernel event structure.
 833  */
 834 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 835 {
 836         assert(event);
 837
 838         if (event->fd >= 0) {
 839                 int ret;
 840
 841                 DBG("[trace] Closing event fd %d", event->fd);
 842                 /* Close kernel fd */
 843                 ret = close(event->fd);
 844                 if (ret) {
 845                         PERROR("close");
 846                 }
 847         } else {
 848                 DBG("[trace] Tearing down event (no associated file descriptor)");
 849         }
 850
 851         /* Remove from event list */
 852         cds_list_del(&event->list);
 853
 854         free(event->filter_expression);
 855         free(event->filter);
 856
 857         free(event->event);
 858         free(event);
 859 }
 860
 861 /*
 862  * Cleanup kernel event structure.
 863  */
 864 static void free_token_event_rule_rcu(struct rcu_head *rcu_node)
 865 {
 866         struct ltt_kernel_event_notifier_rule *rule = caa_container_of(rcu_node,
 867                         struct ltt_kernel_event_notifier_rule, rcu_node);
 868
 869         free(rule);
 870 }
 871
 872 void trace_kernel_destroy_event_notifier_rule(
 873                 struct ltt_kernel_event_notifier_rule *event)
 874 {
 875         assert(event);
 876
 877         if (event->fd >= 0) {
 878                 const int ret = close(event->fd);
 879
 880                 DBG("Closing kernel event notifier rule file descriptor: fd = %d",
 881                                 event->fd);
 882                 if (ret) {
 883                         PERROR("Failed to close kernel event notifier file descriptor: fd = %d",
 884                                         event->fd);
 885                 }
 886         } else {
 887                 DBG("Destroying kernel event notifier rule (no associated file descriptor)");
 888         }
 889
 890         lttng_trigger_put(event->trigger);
 891         call_rcu(&event->rcu_node, free_token_event_rule_rcu);
 892 }
 893 /*
 894  * Cleanup kernel context structure.
 895  */
 896 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 897 {
 898         assert(ctx);
 899
 900         if (ctx->in_list) {
 901                 cds_list_del(&ctx->list);
 902         }
 903         free(ctx);
 904 }
 905
 906 /*
 907  * Cleanup kernel channel structure.
 908  */
 909 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 910 {
 911         struct ltt_kernel_stream *stream, *stmp;
 912         struct ltt_kernel_event *event, *etmp;
 913         struct ltt_kernel_context *ctx, *ctmp;
 914         int ret;
 915         enum lttng_error_code status;
 916
 917         assert(channel);
 918
 919         DBG("[trace] Closing channel fd %d", channel->fd);
 920         /* Close kernel fd */
 921         if (channel->fd >= 0) {
 922                 ret = close(channel->fd);
 923                 if (ret) {
 924                         PERROR("close");
 925                 }
 926         }
 927
 928         /* For each stream in the channel list */
 929         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 930                 trace_kernel_destroy_stream(stream);
 931         }
 932
 933         /* For each event in the channel list */
 934         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 935                 trace_kernel_destroy_event(event);
 936         }
 937
 938         /* For each context in the channel list */
 939         cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
 940                 trace_kernel_destroy_context(ctx);
 941         }
 942
 943         /* Remove from channel list */
 944         cds_list_del(&channel->list);
 945
 946         if (notification_thread_handle
 947                         && channel->published_to_notification_thread) {
 948                 status = notification_thread_command_remove_channel(
 949                                 notification_thread_handle,
 950                                 channel->key, LTTNG_DOMAIN_KERNEL);
 951                 assert(status == LTTNG_OK);
 952         }
 953         free(channel->channel->attr.extended.ptr);
 954         free(channel->channel);
 955         free(channel);
 956 }
 957
 958 /*
 959  * Cleanup kernel metadata structure.
 960  */
 961 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 962 {
 963         assert(metadata);
 964
 965         DBG("[trace] Closing metadata fd %d", metadata->fd);
 966         /* Close kernel fd */
 967         if (metadata->fd >= 0) {
 968                 int ret;
 969
 970                 ret = close(metadata->fd);
 971                 if (ret) {
 972                         PERROR("close");
 973                 }
 974         }
 975
 976         free(metadata->conf);
 977         free(metadata);
 978 }
 979
 980 /*
 981  * Cleanup kernel session structure
 982  *
 983  * Should *NOT* be called with RCU read-side lock held.
 984  */
 985 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 986 {
 987         struct ltt_kernel_channel *channel, *ctmp;
 988         int ret;
 989
 990         assert(session);
 991
 992         DBG("[trace] Closing session fd %d", session->fd);
 993         /* Close kernel fds */
 994         if (session->fd >= 0) {
 995                 ret = close(session->fd);
 996                 if (ret) {
 997                         PERROR("close");
 998                 }
 999         }
1000
1001         if (session->metadata_stream_fd >= 0) {
1002                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
1003                 ret = close(session->metadata_stream_fd);
1004                 if (ret) {
1005                         PERROR("close");
1006                 }
1007         }
1008
1009         if (session->metadata != NULL) {
1010                 trace_kernel_destroy_metadata(session->metadata);
1011         }
1012
1013         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
1014                 trace_kernel_destroy_channel(channel);
1015         }
1016 }
1017
1018 /* Free elements needed by destroy notifiers. */
1019 void trace_kernel_free_session(struct ltt_kernel_session *session)
1020 {
1021         /* Wipe consumer output object */
1022         consumer_output_put(session->consumer);
1023
1024         process_attr_tracker_destroy(session->tracker_pid);
1025         process_attr_tracker_destroy(session->tracker_vpid);
1026         process_attr_tracker_destroy(session->tracker_uid);
1027         process_attr_tracker_destroy(session->tracker_vuid);
1028         process_attr_tracker_destroy(session->tracker_gid);
1029         process_attr_tracker_destroy(session->tracker_vgid);
1030
1031         free(session);
1032 }