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