src/bin/lttng-sessiond/event.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <errno.h>
  20 #include <urcu/list.h>
  21 #include <string.h>
  22
  23 #include <lttng/lttng.h>
  24 #include <common/error.h>
  25 #include <common/sessiond-comm/sessiond-comm.h>
  26
  27 #include "channel.h"
  28 #include "event.h"
  29 #include "kernel.h"
  30 #include "ust-ctl.h"
  31 #include "ust-app.h"
  32 #include "trace-kernel.h"
  33 #include "trace-ust.h"
  34
  35 /*
  36  * Add unique UST event based on the event name, filter bytecode and loglevel.
  37  */
  38 static void add_unique_ust_event(struct lttng_ht *ht,
  39                 struct ltt_ust_event *event)
  40 {
  41         struct cds_lfht_node *node_ptr;
  42         struct ltt_ust_ht_key key;
  43
  44         assert(ht);
  45         assert(ht->ht);
  46         assert(event);
  47
  48         key.name = event->attr.name;
  49         key.filter = (struct lttng_filter_bytecode *) event->filter;
  50         key.loglevel = event->attr.loglevel;
  51
  52         node_ptr = cds_lfht_add_unique(ht->ht,
  53                         ht->hash_fct(event->node.key, lttng_ht_seed),
  54                         trace_ust_ht_match_event, &key, &event->node.node);
  55         assert(node_ptr == &event->node.node);
  56 }
  57
  58 /*
  59  * Setup a lttng_event used to enable *all* syscall tracing.
  60  */
  61 static void init_syscalls_kernel_event(struct lttng_event *event)
  62 {
  63         assert(event);
  64
  65         event->name[0] = '\0';
  66         /*
  67          * We use LTTNG_EVENT* here since the trace kernel creation will make the
  68          * right changes for the kernel.
  69          */
  70         event->type = LTTNG_EVENT_SYSCALL;
  71 }
  72
  73 /*
  74  * Disable kernel tracepoint event for a channel from the kernel session.
  75  */
  76 int event_kernel_disable_tracepoint(struct ltt_kernel_session *ksession,
  77                 struct ltt_kernel_channel *kchan, char *event_name)
  78 {
  79         int ret;
  80         struct ltt_kernel_event *kevent;
  81
  82         assert(kchan);
  83
  84         kevent = trace_kernel_get_event_by_name(event_name, kchan);
  85         if (kevent == NULL) {
  86                 ret = LTTNG_ERR_NO_EVENT;
  87                 goto error;
  88         }
  89
  90         ret = kernel_disable_event(kevent);
  91         if (ret < 0) {
  92                 ret = LTTNG_ERR_KERN_DISABLE_FAIL;
  93                 goto error;
  94         }
  95
  96         DBG("Kernel event %s disable for channel %s.",
  97                         kevent->event->name, kchan->channel->name);
  98
  99         ret = LTTNG_OK;
 100
 101 error:
 102         return ret;
 103 }
 104
 105 /*
 106  * Disable kernel tracepoint events for a channel from the kernel session.
 107  */
 108 int event_kernel_disable_all_tracepoints(struct ltt_kernel_session *ksession,
 109                 struct ltt_kernel_channel *kchan)
 110 {
 111         int ret;
 112         struct ltt_kernel_event *kevent;
 113
 114         assert(kchan);
 115
 116         /* For each event in the kernel session */
 117         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
 118                 ret = kernel_disable_event(kevent);
 119                 if (ret < 0) {
 120                         /* We continue disabling the rest */
 121                         continue;
 122                 }
 123         }
 124         ret = LTTNG_OK;
 125         return ret;
 126 }
 127
 128 /*
 129  * Disable kernel syscall events for a channel from the kernel session.
 130  */
 131 int event_kernel_disable_all_syscalls(struct ltt_kernel_session *ksession,
 132                 struct ltt_kernel_channel *kchan)
 133 {
 134         ERR("Cannot disable syscall tracing for existing session. Please destroy session instead.");
 135         return LTTNG_OK;        /* Return OK so disable all succeeds */
 136 }
 137
 138 /*
 139  * Disable all kernel event for a channel from the kernel session.
 140  */
 141 int event_kernel_disable_all(struct ltt_kernel_session *ksession,
 142                 struct ltt_kernel_channel *kchan)
 143 {
 144         int ret;
 145
 146         assert(ksession);
 147         assert(kchan);
 148
 149         ret = event_kernel_disable_all_tracepoints(ksession, kchan);
 150         if (ret != LTTNG_OK)
 151                 return ret;
 152         ret = event_kernel_disable_all_syscalls(ksession, kchan);
 153         return ret;
 154 }
 155
 156 /*
 157  * Enable kernel tracepoint event for a channel from the kernel session.
 158  */
 159 int event_kernel_enable_tracepoint(struct ltt_kernel_session *ksession,
 160                 struct ltt_kernel_channel *kchan, struct lttng_event *event)
 161 {
 162         int ret;
 163         struct ltt_kernel_event *kevent;
 164
 165         assert(kchan);
 166         assert(event);
 167
 168         kevent = trace_kernel_get_event_by_name(event->name, kchan);
 169         if (kevent == NULL) {
 170                 ret = kernel_create_event(event, kchan);
 171                 if (ret < 0) {
 172                         switch (-ret) {
 173                         case EEXIST:
 174                                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 175                                 break;
 176                         case ENOSYS:
 177                                 ret = LTTNG_ERR_KERN_EVENT_ENOSYS;
 178                                 break;
 179                         default:
 180                                 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 181                                 break;
 182                         }
 183                         goto end;
 184                 }
 185         } else if (kevent->enabled == 0) {
 186                 ret = kernel_enable_event(kevent);
 187                 if (ret < 0) {
 188                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 189                         goto end;
 190                 }
 191         } else {
 192                 /* At this point, the event is considered enabled */
 193                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 194                 goto end;
 195         }
 196
 197         ret = LTTNG_OK;
 198 end:
 199         return ret;
 200 }
 201
 202 /*
 203  * Enable all kernel tracepoint events of a channel of the kernel session.
 204  */
 205 int event_kernel_enable_all_tracepoints(struct ltt_kernel_session *ksession,
 206                 struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 207 {
 208         int size, i, ret;
 209         struct ltt_kernel_event *kevent;
 210         struct lttng_event *event_list = NULL;
 211
 212         assert(kchan);
 213
 214         /* For each event in the kernel session */
 215         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
 216                 if (kevent->enabled == 0) {
 217                         ret = kernel_enable_event(kevent);
 218                         if (ret < 0) {
 219                                 /* Enable failed but still continue */
 220                                 continue;
 221                         }
 222                 }
 223         }
 224
 225         size = kernel_list_events(kernel_tracer_fd, &event_list);
 226         if (size < 0) {
 227                 ret = LTTNG_ERR_KERN_LIST_FAIL;
 228                 goto end;
 229         }
 230
 231         for (i = 0; i < size; i++) {
 232                 kevent = trace_kernel_get_event_by_name(event_list[i].name, kchan);
 233                 if (kevent == NULL) {
 234                         /* Default event type for enable all */
 235                         event_list[i].type = LTTNG_EVENT_TRACEPOINT;
 236                         /* Enable each single tracepoint event */
 237                         ret = kernel_create_event(&event_list[i], kchan);
 238                         if (ret < 0) {
 239                                 /* Ignore error here and continue */
 240                         }
 241                 }
 242         }
 243         free(event_list);
 244
 245         ret = LTTNG_OK;
 246 end:
 247         return ret;
 248 }
 249
 250 /*
 251  * Enable all kernel tracepoint events of a channel of the kernel session.
 252  */
 253 int event_kernel_enable_all_syscalls(struct ltt_kernel_session *ksession,
 254                 struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 255 {
 256         int ret;
 257         struct lttng_event event;
 258
 259         assert(kchan);
 260
 261         init_syscalls_kernel_event(&event);
 262
 263         DBG("Enabling all syscall tracing");
 264
 265         ret = kernel_create_event(&event, kchan);
 266         if (ret < 0) {
 267                 if (ret == -EEXIST) {
 268                         ret = LTTNG_ERR_KERN_EVENT_EXIST;
 269                 } else {
 270                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 271                 }
 272                 goto end;
 273         }
 274
 275         ret = LTTNG_OK;
 276 end:
 277         return ret;
 278 }
 279
 280 /*
 281  * Enable all kernel events of a channel of the kernel session.
 282  */
 283 int event_kernel_enable_all(struct ltt_kernel_session *ksession,
 284                 struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 285 {
 286         int tp_ret;
 287
 288         assert(ksession);
 289         assert(kchan);
 290
 291         tp_ret = event_kernel_enable_all_tracepoints(ksession, kchan,
 292                         kernel_tracer_fd);
 293         if (tp_ret != LTTNG_OK) {
 294                 goto end;
 295         }
 296
 297         /*
 298          * Reaching this code path means that all tracepoints were enabled without
 299          * errors so we ignore the error value of syscalls.
 300          *
 301          * At the moment, failing to enable syscalls on "lttng enable-event -a -k"
 302          * is not considered an error that need to be returned to the client since
 303          * tracepoints did not fail. Future work will allow us to send back
 304          * multiple errors to the client in one API call.
 305          */
 306         (void) event_kernel_enable_all_syscalls(ksession, kchan, kernel_tracer_fd);
 307
 308 end:
 309         return tp_ret;
 310 }
 311
 312 /*
 313  * ============================
 314  * UST : The Ultimate Frontier!
 315  * ============================
 316  */
 317
 318 /*
 319  * Enable all UST tracepoints for a channel from a UST session.
 320  */
 321 int event_ust_enable_all_tracepoints(struct ltt_ust_session *usess, int domain,
 322                 struct ltt_ust_channel *uchan, struct lttng_filter_bytecode *filter)
 323 {
 324         int ret, i, size;
 325         struct lttng_ht_iter iter;
 326         struct ltt_ust_event *uevent = NULL;
 327         struct lttng_event *events = NULL;
 328
 329         assert(usess);
 330         assert(uchan);
 331
 332         rcu_read_lock();
 333
 334         switch (domain) {
 335         case LTTNG_DOMAIN_UST:
 336         {
 337                 /* Enable existing events */
 338                 cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 339                                 node.node) {
 340                         if (uevent->enabled == 0) {
 341                                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 342                                 if (ret < 0) {
 343                                         continue;
 344                                 }
 345                                 uevent->enabled = 1;
 346                         }
 347                 }
 348
 349                 /* Get all UST available events */
 350                 size = ust_app_list_events(&events);
 351                 if (size < 0) {
 352                         ret = LTTNG_ERR_UST_LIST_FAIL;
 353                         goto error;
 354                 }
 355
 356                 for (i = 0; i < size; i++) {
 357                         /*
 358                          * Check if event exist and if so, continue since it was enable
 359                          * previously.
 360                          */
 361                         uevent = trace_ust_find_event(uchan->events, events[i].name, filter,
 362                                         events[i].loglevel);
 363                         if (uevent != NULL) {
 364                                 ret = ust_app_enable_event_pid(usess, uchan, uevent,
 365                                                 events[i].pid);
 366                                 if (ret < 0) {
 367                                         if (ret != -LTTNG_UST_ERR_EXIST) {
 368                                                 ret = LTTNG_ERR_UST_ENABLE_FAIL;
 369                                                 goto error;
 370                                         }
 371                                 }
 372                                 continue;
 373                         }
 374
 375                         /* Create ust event */
 376                         uevent = trace_ust_create_event(&events[i], filter);
 377                         if (uevent == NULL) {
 378                                 ret = LTTNG_ERR_FATAL;
 379                                 goto error_destroy;
 380                         }
 381
 382                         /* Create event for the specific PID */
 383                         ret = ust_app_enable_event_pid(usess, uchan, uevent,
 384                                         events[i].pid);
 385                         if (ret < 0) {
 386                                 if (ret == -LTTNG_UST_ERR_EXIST) {
 387                                         ret = LTTNG_ERR_UST_EVENT_EXIST;
 388                                         goto error;
 389                                 } else {
 390                                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 391                                         goto error_destroy;
 392                                 }
 393                         }
 394
 395                         uevent->enabled = 1;
 396                         /* Add ltt ust event to channel */
 397                         rcu_read_lock();
 398                         add_unique_ust_event(uchan->events, uevent);
 399                         rcu_read_unlock();
 400                 }
 401
 402                 free(events);
 403                 break;
 404         }
 405 #if 0
 406         case LTTNG_DOMAIN_UST_EXEC_NAME:
 407         case LTTNG_DOMAIN_UST_PID:
 408         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 409 #endif
 410         default:
 411                 ret = LTTNG_ERR_UND;
 412                 goto error;
 413         }
 414
 415         rcu_read_unlock();
 416         return LTTNG_OK;
 417
 418 error_destroy:
 419         trace_ust_destroy_event(uevent);
 420
 421 error:
 422         free(events);
 423         rcu_read_unlock();
 424         return ret;
 425 }
 426
 427 /*
 428  * Enable UST tracepoint event for a channel from a UST session.
 429  */
 430 int event_ust_enable_tracepoint(struct ltt_ust_session *usess, int domain,
 431                 struct ltt_ust_channel *uchan, struct lttng_event *event,
 432                 struct lttng_filter_bytecode *filter)
 433 {
 434         int ret = LTTNG_OK, to_create = 0;
 435         struct ltt_ust_event *uevent;
 436
 437         assert(usess);
 438         assert(uchan);
 439         assert(event);
 440
 441         rcu_read_lock();
 442
 443         uevent = trace_ust_find_event(uchan->events, event->name, filter,
 444                         event->loglevel);
 445         if (uevent == NULL) {
 446                 uevent = trace_ust_create_event(event, filter);
 447                 if (uevent == NULL) {
 448                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 449                         goto error;
 450                 }
 451
 452                 /* Valid to set it after the goto error since uevent is still NULL */
 453                 to_create = 1;
 454         }
 455
 456         if (uevent->enabled) {
 457                 /* It's already enabled so everything is OK */
 458                 ret = LTTNG_ERR_UST_EVENT_ENABLED;
 459                 goto end;
 460         }
 461
 462         uevent->enabled = 1;
 463
 464         switch (domain) {
 465         case LTTNG_DOMAIN_UST:
 466         {
 467                 if (to_create) {
 468                         /* Create event on all UST registered apps for session */
 469                         ret = ust_app_create_event_glb(usess, uchan, uevent);
 470                 } else {
 471                         /* Enable event on all UST registered apps for session */
 472                         ret = ust_app_enable_event_glb(usess, uchan, uevent);
 473                 }
 474
 475                 if (ret < 0) {
 476                         if (ret == -LTTNG_UST_ERR_EXIST) {
 477                                 ret = LTTNG_ERR_UST_EVENT_EXIST;
 478                                 goto end;
 479                         } else {
 480                                 ret = LTTNG_ERR_UST_ENABLE_FAIL;
 481                                 goto error;
 482                         }
 483                 }
 484                 break;
 485         }
 486 #if 0
 487         case LTTNG_DOMAIN_UST_EXEC_NAME:
 488         case LTTNG_DOMAIN_UST_PID:
 489         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 490 #endif
 491         default:
 492                 ret = LTTNG_ERR_UND;
 493                 goto end;
 494         }
 495
 496         if (to_create) {
 497                 /* Add ltt ust event to channel */
 498                 add_unique_ust_event(uchan->events, uevent);
 499         }
 500
 501         DBG("Event UST %s %s in channel %s", uevent->attr.name,
 502                         to_create ? "created" : "enabled", uchan->name);
 503
 504         ret = LTTNG_OK;
 505
 506 end:
 507         rcu_read_unlock();
 508         return ret;
 509
 510 error:
 511         /*
 512          * Only destroy event on creation time (not enabling time) because if the
 513          * event is found in the channel (to_create == 0), it means that at some
 514          * point the enable_event worked and it's thus valid to keep it alive.
 515          * Destroying it also implies that we also destroy it's shadow copy to sync
 516          * everyone up.
 517          */
 518         if (to_create) {
 519                 /* In this code path, the uevent was not added to the hash table */
 520                 trace_ust_destroy_event(uevent);
 521         }
 522         rcu_read_unlock();
 523         return ret;
 524 }
 525
 526 /*
 527  * Disable UST tracepoint of a channel from a UST session.
 528  */
 529 int event_ust_disable_tracepoint(struct ltt_ust_session *usess, int domain,
 530                 struct ltt_ust_channel *uchan, char *event_name)
 531 {
 532         int ret;
 533         struct ltt_ust_event *uevent;
 534         struct lttng_ht_node_str *node;
 535         struct lttng_ht_iter iter;
 536         struct lttng_ht *ht;
 537
 538         assert(usess);
 539         assert(uchan);
 540         assert(event_name);
 541
 542         ht = uchan->events;
 543
 544         rcu_read_lock();
 545
 546         /*
 547          * We use a custom lookup since we need the iterator for the next_duplicate
 548          * call in the do while loop below.
 549          */
 550         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) event_name, lttng_ht_seed),
 551                         trace_ust_ht_match_event_by_name, event_name, &iter.iter);
 552         node = lttng_ht_iter_get_node_str(&iter);
 553         if (node == NULL) {
 554                 DBG2("Trace UST event NOT found by name %s", event_name);
 555                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 556                 goto error;
 557         }
 558
 559         do {
 560                 uevent = caa_container_of(node, struct ltt_ust_event, node);
 561                 assert(uevent);
 562
 563                 if (uevent->enabled == 0) {
 564                         /* It's already disabled so everything is OK */
 565                         ret = LTTNG_OK;
 566                         continue;
 567                 }
 568
 569                 switch (domain) {
 570                 case LTTNG_DOMAIN_UST:
 571                         ret = ust_app_disable_event_glb(usess, uchan, uevent);
 572                         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 573                                 ret = LTTNG_ERR_UST_DISABLE_FAIL;
 574                                 goto error;
 575                         }
 576                         break;
 577 #if 0
 578                 case LTTNG_DOMAIN_UST_EXEC_NAME:
 579                 case LTTNG_DOMAIN_UST_PID:
 580                 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 581 #endif
 582                 default:
 583                         ret = LTTNG_ERR_UND;
 584                         goto error;
 585                 }
 586
 587                 uevent->enabled = 0;
 588
 589                 DBG2("Event UST %s disabled in channel %s", uevent->attr.name,
 590                                 uchan->name);
 591
 592                 /* Get next duplicate event by name. */
 593                 cds_lfht_next_duplicate(ht->ht, trace_ust_ht_match_event_by_name,
 594                                 event_name, &iter.iter);
 595                 node = lttng_ht_iter_get_node_str(&iter);
 596         } while (node);
 597
 598         ret = LTTNG_OK;
 599
 600 error:
 601         rcu_read_unlock();
 602         return ret;
 603 }
 604
 605 /*
 606  * Disable all UST tracepoints for a channel from a UST session.
 607  */
 608 int event_ust_disable_all_tracepoints(struct ltt_ust_session *usess, int domain,
 609                 struct ltt_ust_channel *uchan)
 610 {
 611         int ret, i, size;
 612         struct lttng_ht_iter iter;
 613         struct ltt_ust_event *uevent = NULL;
 614         struct lttng_event *events = NULL;
 615
 616         assert(usess);
 617         assert(uchan);
 618
 619         rcu_read_lock();
 620
 621         switch (domain) {
 622         case LTTNG_DOMAIN_UST:
 623         {
 624                 /* Disabling existing events */
 625                 cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 626                                 node.node) {
 627                         if (uevent->enabled == 1) {
 628                                 ret = event_ust_disable_tracepoint(usess, domain, uchan,
 629                                                 uevent->attr.name);
 630                                 if (ret < 0) {
 631                                         continue;
 632                                 }
 633                         }
 634                 }
 635
 636                 /* Get all UST available events */
 637                 size = ust_app_list_events(&events);
 638                 if (size < 0) {
 639                         ret = LTTNG_ERR_UST_LIST_FAIL;
 640                         goto error;
 641                 }
 642
 643                 for (i = 0; i < size; i++) {
 644                         ret = event_ust_disable_tracepoint(usess, domain, uchan,
 645                                         events[i].name);
 646                         if (ret != LTTNG_OK) {
 647                                 /* Continue to disable the rest... */
 648                                 continue;
 649                         }
 650                 }
 651
 652                 free(events);
 653                 break;
 654         }
 655 #if 0
 656         case LTTNG_DOMAIN_UST_EXEC_NAME:
 657         case LTTNG_DOMAIN_UST_PID:
 658         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 659 #endif
 660         default:
 661                 ret = LTTNG_ERR_UND;
 662                 goto error;
 663         }
 664
 665         rcu_read_unlock();
 666         return LTTNG_OK;
 667
 668 error:
 669         free(events);
 670         rcu_read_unlock();
 671         return ret;
 672 }