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  * Setup a lttng_event used to enable *all* syscall tracing.
  37  */
  38 static void init_syscalls_kernel_event(struct lttng_event *event)
  39 {
  40         event->name[0] = '\0';
  41         /*
  42          * We use LTTNG_EVENT* here since the trace kernel creation will make the
  43          * right changes for the kernel.
  44          */
  45         event->type = LTTNG_EVENT_SYSCALL;
  46 }
  47
  48 /*
  49  * Disable kernel tracepoint event for a channel from the kernel session.
  50  */
  51 int event_kernel_disable_tracepoint(struct ltt_kernel_session *ksession,
  52                 struct ltt_kernel_channel *kchan, char *event_name)
  53 {
  54         int ret;
  55         struct ltt_kernel_event *kevent;
  56
  57         kevent = trace_kernel_get_event_by_name(event_name, kchan);
  58         if (kevent == NULL) {
  59                 ret = LTTCOMM_NO_EVENT;
  60                 goto error;
  61         }
  62
  63         ret = kernel_disable_event(kevent);
  64         if (ret < 0) {
  65                 ret = LTTCOMM_KERN_DISABLE_FAIL;
  66                 goto error;
  67         }
  68
  69         DBG("Kernel event %s disable for channel %s.",
  70                         kevent->event->name, kchan->channel->name);
  71
  72         ret = LTTCOMM_OK;
  73
  74 error:
  75         return ret;
  76 }
  77
  78 /*
  79  * Disable kernel tracepoint events for a channel from the kernel session.
  80  */
  81 int event_kernel_disable_all_tracepoints(struct ltt_kernel_session *ksession,
  82                 struct ltt_kernel_channel *kchan)
  83 {
  84         int ret;
  85         struct ltt_kernel_event *kevent;
  86
  87         /* For each event in the kernel session */
  88         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
  89                 ret = kernel_disable_event(kevent);
  90                 if (ret < 0) {
  91                         /* We continue disabling the rest */
  92                         continue;
  93                 }
  94         }
  95         ret = LTTCOMM_OK;
  96         return ret;
  97 }
  98
  99 /*
 100  * Disable kernel syscall events for a channel from the kernel session.
 101  */
 102 int event_kernel_disable_all_syscalls(struct ltt_kernel_session *ksession,
 103                 struct ltt_kernel_channel *kchan)
 104 {
 105         ERR("Cannot disable syscall tracing for existing session. Please destroy session instead.");
 106         return LTTCOMM_OK;      /* Return OK so disable all succeeds */
 107 }
 108
 109 /*
 110  * Disable all kernel event for a channel from the kernel session.
 111  */
 112 int event_kernel_disable_all(struct ltt_kernel_session *ksession,
 113                 struct ltt_kernel_channel *kchan)
 114 {
 115         int ret;
 116
 117         ret = event_kernel_disable_all_tracepoints(ksession, kchan);
 118         if (ret != LTTCOMM_OK)
 119                 return ret;
 120         ret = event_kernel_disable_all_syscalls(ksession, kchan);
 121         return ret;
 122 }
 123
 124 /*
 125  * Enable kernel tracepoint event for a channel from the kernel session.
 126  */
 127 int event_kernel_enable_tracepoint(struct ltt_kernel_session *ksession,
 128                 struct ltt_kernel_channel *kchan, struct lttng_event *event)
 129 {
 130         int ret;
 131         struct ltt_kernel_event *kevent;
 132
 133         kevent = trace_kernel_get_event_by_name(event->name, kchan);
 134         if (kevent == NULL) {
 135                 ret = kernel_create_event(event, kchan);
 136                 if (ret < 0) {
 137                         switch (-ret) {
 138                         case EEXIST:
 139                                 ret = LTTCOMM_KERN_EVENT_EXIST;
 140                                 break;
 141                         case ENOSYS:
 142                                 ret = LTTCOMM_KERN_EVENT_ENOSYS;
 143                                 break;
 144                         default:
 145                                 ret = LTTCOMM_KERN_ENABLE_FAIL;
 146                                 break;
 147                         }
 148                         goto end;
 149                 }
 150         } else if (kevent->enabled == 0) {
 151                 ret = kernel_enable_event(kevent);
 152                 if (ret < 0) {
 153                         ret = LTTCOMM_KERN_ENABLE_FAIL;
 154                         goto end;
 155                 }
 156         } else {
 157                 /* At this point, the event is considered enabled */
 158                 ret = LTTCOMM_KERN_EVENT_EXIST;
 159                 goto end;
 160         }
 161
 162         ret = LTTCOMM_OK;
 163 end:
 164         return ret;
 165 }
 166
 167 /*
 168  * Enable all kernel tracepoint events of a channel of the kernel session.
 169  */
 170 int event_kernel_enable_all_tracepoints(struct ltt_kernel_session *ksession,
 171                 struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 172 {
 173         int size, i, ret;
 174         struct ltt_kernel_event *kevent;
 175         struct lttng_event *event_list = NULL;
 176
 177         /* For each event in the kernel session */
 178         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
 179                 if (kevent->enabled == 0) {
 180                         ret = kernel_enable_event(kevent);
 181                         if (ret < 0) {
 182                                 /* Enable failed but still continue */
 183                                 continue;
 184                         }
 185                 }
 186         }
 187
 188         size = kernel_list_events(kernel_tracer_fd, &event_list);
 189         if (size < 0) {
 190                 ret = LTTCOMM_KERN_LIST_FAIL;
 191                 goto end;
 192         }
 193
 194         for (i = 0; i < size; i++) {
 195                 kevent = trace_kernel_get_event_by_name(event_list[i].name, kchan);
 196                 if (kevent == NULL) {
 197                         /* Default event type for enable all */
 198                         event_list[i].type = LTTNG_EVENT_TRACEPOINT;
 199                         /* Enable each single tracepoint event */
 200                         ret = kernel_create_event(&event_list[i], kchan);
 201                         if (ret < 0) {
 202                                 /* Ignore error here and continue */
 203                         }
 204                 }
 205         }
 206         free(event_list);
 207
 208         ret = LTTCOMM_OK;
 209 end:
 210         return ret;
 211
 212 }
 213
 214 /*
 215  * Enable all kernel tracepoint events of a channel of the kernel session.
 216  */
 217 int event_kernel_enable_all_syscalls(struct ltt_kernel_session *ksession,
 218                 struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 219 {
 220         int ret;
 221         struct lttng_event event;
 222
 223         init_syscalls_kernel_event(&event);
 224
 225         DBG("Enabling all syscall tracing");
 226
 227         ret = kernel_create_event(&event, kchan);
 228         if (ret < 0) {
 229                 if (ret == -EEXIST) {
 230                         ret = LTTCOMM_KERN_EVENT_EXIST;
 231                 } else {
 232                         ret = LTTCOMM_KERN_ENABLE_FAIL;
 233                 }
 234                 goto end;
 235         }
 236
 237         ret = LTTCOMM_OK;
 238 end:
 239         return ret;
 240 }
 241
 242 /*
 243  * Enable all kernel events of a channel of the kernel session.
 244  */
 245 int event_kernel_enable_all(struct ltt_kernel_session *ksession,
 246                 struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 247 {
 248         int tp_ret, syscall_ret;
 249
 250         tp_ret = event_kernel_enable_all_tracepoints(ksession, kchan, kernel_tracer_fd);
 251         if (tp_ret != LTTCOMM_OK) {
 252                 goto end;
 253         }
 254
 255         /*
 256          * Reaching this code path means that all tracepoints were enabled without
 257          * errors so we ignore the error value of syscalls.
 258          *
 259          * At the moment, failing to enable syscalls on "lttng enable-event -a -k"
 260          * is not considered an error that need to be returned to the client since
 261          * tracepoints did not fail. Future work will allow us to send back
 262          * multiple errors to the client in one API call.
 263          */
 264         syscall_ret = event_kernel_enable_all_syscalls(ksession, kchan,
 265                         kernel_tracer_fd);
 266
 267 end:
 268         return tp_ret;
 269 }
 270
 271 /*
 272  * ============================
 273  * UST : The Ultimate Frontier!
 274  * ============================
 275  */
 276
 277 /*
 278  * Enable all UST tracepoints for a channel from a UST session.
 279  */
 280 int event_ust_enable_all_tracepoints(struct ltt_ust_session *usess, int domain,
 281                 struct ltt_ust_channel *uchan)
 282 {
 283         int ret, i;
 284         size_t size;
 285         struct lttng_ht_iter iter;
 286         struct ltt_ust_event *uevent = NULL;
 287         struct lttng_event *events = NULL;
 288
 289         switch (domain) {
 290         case LTTNG_DOMAIN_UST:
 291         {
 292                 /* Enable existing events */
 293                 cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 294                                 node.node) {
 295                         if (uevent->enabled == 0) {
 296                                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 297                                 if (ret < 0) {
 298                                         continue;
 299                                 }
 300                                 uevent->enabled = 1;
 301                         }
 302                 }
 303
 304                 /* Get all UST available events */
 305                 size = ust_app_list_events(&events);
 306                 if (size < 0) {
 307                         ret = LTTCOMM_UST_LIST_FAIL;
 308                         goto error;
 309                 }
 310
 311                 for (i = 0; i < size; i++) {
 312                         /*
 313                          * Check if event exist and if so, continue since it was enable
 314                          * previously.
 315                          */
 316                         uevent = trace_ust_find_event_by_name(uchan->events,
 317                                         events[i].name);
 318                         if (uevent != NULL) {
 319                                 ret = ust_app_enable_event_pid(usess, uchan, uevent,
 320                                                 events[i].pid);
 321                                 if (ret < 0) {
 322                                         if (ret != -EEXIST) {
 323                                                 ret = LTTCOMM_UST_ENABLE_FAIL;
 324                                                 goto error;
 325                                         }
 326                                 }
 327                                 continue;
 328                         }
 329
 330                         /* Create ust event */
 331                         uevent = trace_ust_create_event(&events[i]);
 332                         if (uevent == NULL) {
 333                                 ret = LTTCOMM_FATAL;
 334                                 goto error_destroy;
 335                         }
 336
 337                         /* Create event for the specific PID */
 338                         ret = ust_app_enable_event_pid(usess, uchan, uevent,
 339                                         events[i].pid);
 340                         if (ret < 0) {
 341                                 if (ret == -EEXIST) {
 342                                         ret = LTTCOMM_UST_EVENT_EXIST;
 343                                         goto error;
 344                                 } else {
 345                                         ret = LTTCOMM_UST_ENABLE_FAIL;
 346                                         goto error_destroy;
 347                                 }
 348                         }
 349
 350                         uevent->enabled = 1;
 351                         /* Add ltt ust event to channel */
 352                         rcu_read_lock();
 353                         lttng_ht_add_unique_str(uchan->events, &uevent->node);
 354                         rcu_read_unlock();
 355                 }
 356
 357                 free(events);
 358                 break;
 359         }
 360 #if 0
 361         case LTTNG_DOMAIN_UST_EXEC_NAME:
 362         case LTTNG_DOMAIN_UST_PID:
 363         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 364 #endif
 365         default:
 366                 ret = LTTCOMM_UND;
 367                 goto error;
 368         }
 369
 370         return LTTCOMM_OK;
 371
 372 error_destroy:
 373         trace_ust_destroy_event(uevent);
 374
 375 error:
 376         free(events);
 377         return ret;
 378 }
 379
 380 /*
 381  * Enable UST tracepoint event for a channel from a UST session.
 382  */
 383 int event_ust_enable_tracepoint(struct ltt_ust_session *usess, int domain,
 384                 struct ltt_ust_channel *uchan, struct lttng_event *event)
 385 {
 386         int ret = LTTCOMM_OK, to_create = 0;
 387         struct ltt_ust_event *uevent;
 388
 389         uevent = trace_ust_find_event_by_name(uchan->events, event->name);
 390         if (uevent == NULL) {
 391                 uevent = trace_ust_create_event(event);
 392                 if (uevent == NULL) {
 393                         ret = LTTCOMM_FATAL;
 394                         goto error;
 395                 }
 396                 /* Valid to set it after the goto error since uevent is still NULL */
 397                 to_create = 1;
 398         }
 399
 400         if (uevent->enabled) {
 401                 /* It's already enabled so everything is OK */
 402                 goto end;
 403         }
 404
 405         uevent->enabled = 1;
 406
 407         switch (domain) {
 408         case LTTNG_DOMAIN_UST:
 409         {
 410                 if (to_create) {
 411                         /* Create event on all UST registered apps for session */
 412                         ret = ust_app_create_event_glb(usess, uchan, uevent);
 413                 } else {
 414                         /* Enable event on all UST registered apps for session */
 415                         ret = ust_app_enable_event_glb(usess, uchan, uevent);
 416                 }
 417
 418                 if (ret < 0) {
 419                         if (ret == -EEXIST) {
 420                                 ret = LTTCOMM_UST_EVENT_EXIST;
 421                                 goto end;
 422                         } else {
 423                                 ret = LTTCOMM_UST_ENABLE_FAIL;
 424                                 goto error;
 425                         }
 426                 }
 427                 break;
 428         }
 429 #if 0
 430         case LTTNG_DOMAIN_UST_EXEC_NAME:
 431         case LTTNG_DOMAIN_UST_PID:
 432         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 433 #endif
 434         default:
 435                 ret = LTTCOMM_UND;
 436                 goto end;
 437         }
 438
 439         if (to_create) {
 440                 rcu_read_lock();
 441                 /* Add ltt ust event to channel */
 442                 lttng_ht_add_unique_str(uchan->events, &uevent->node);
 443                 rcu_read_unlock();
 444         }
 445
 446         DBG("Event UST %s %s in channel %s", uevent->attr.name,
 447                         to_create ? "created" : "enabled", uchan->name);
 448
 449         ret = LTTCOMM_OK;
 450
 451 end:
 452         return ret;
 453
 454 error:
 455         /*
 456          * Only destroy event on creation time (not enabling time) because if the
 457          * event is found in the channel (to_create == 0), it means that at some
 458          * point the enable_event worked and it's thus valid to keep it alive.
 459          * Destroying it also implies that we also destroy it's shadow copy to sync
 460          * everyone up.
 461          */
 462         if (to_create) {
 463                 /* In this code path, the uevent was not added to the hash table */
 464                 trace_ust_destroy_event(uevent);
 465         }
 466         return ret;
 467 }
 468
 469 /*
 470  * Disable UST tracepoint of a channel from a UST session.
 471  */
 472 int event_ust_disable_tracepoint(struct ltt_ust_session *usess, int domain,
 473                 struct ltt_ust_channel *uchan, char *event_name)
 474 {
 475         int ret;
 476         struct ltt_ust_event *uevent;
 477
 478         uevent = trace_ust_find_event_by_name(uchan->events, event_name);
 479         if (uevent == NULL) {
 480                 ret = LTTCOMM_UST_EVENT_NOT_FOUND;
 481                 goto error;
 482         }
 483
 484         if (uevent->enabled == 0) {
 485                 /* It's already enabled so everything is OK */
 486                 ret = LTTCOMM_OK;
 487                 goto end;
 488         }
 489
 490         switch (domain) {
 491         case LTTNG_DOMAIN_UST:
 492                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 493                 if (ret < 0 && ret != -EEXIST) {
 494                         ret = LTTCOMM_UST_DISABLE_FAIL;
 495                         goto error;
 496                 }
 497                 break;
 498 #if 0
 499         case LTTNG_DOMAIN_UST_EXEC_NAME:
 500         case LTTNG_DOMAIN_UST_PID:
 501         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 502 #endif
 503         default:
 504                 ret = LTTCOMM_UND;
 505                 goto error;
 506         }
 507
 508         uevent->enabled = 0;
 509         ret = LTTCOMM_OK;
 510
 511 end:
 512         DBG2("Event UST %s disabled in channel %s", uevent->attr.name,
 513                         uchan->name);
 514
 515 error:
 516         return ret;
 517 }
 518
 519 /*
 520  * Disable all UST tracepoints for a channel from a UST session.
 521  */
 522 int event_ust_disable_all_tracepoints(struct ltt_ust_session *usess, int domain,
 523                 struct ltt_ust_channel *uchan)
 524 {
 525         int ret, i;
 526         size_t size;
 527         struct lttng_ht_iter iter;
 528         struct ltt_ust_event *uevent = NULL;
 529         struct lttng_event *events = NULL;
 530
 531         switch (domain) {
 532         case LTTNG_DOMAIN_UST:
 533         {
 534                 /* Disabling existing events */
 535                 cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 536                                 node.node) {
 537                         if (uevent->enabled == 1) {
 538                                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 539                                 if (ret < 0) {
 540                                         continue;
 541                                 }
 542                                 uevent->enabled = 0;
 543                         }
 544                 }
 545
 546                 /* Get all UST available events */
 547                 size = ust_app_list_events(&events);
 548                 if (size < 0) {
 549                         ret = LTTCOMM_UST_LIST_FAIL;
 550                         goto error;
 551                 }
 552
 553                 for (i = 0; i < size; i++) {
 554                         uevent = trace_ust_find_event_by_name(uchan->events,
 555                                         events[i].name);
 556                         if (uevent != NULL && uevent->enabled == 1) {
 557                                 ret = ust_app_disable_event_pid(usess, uchan, uevent,
 558                                                 events[i].pid);
 559                                 if (ret < 0 && ret != -EEXIST) {
 560                                         ret = LTTCOMM_UST_DISABLE_FAIL;
 561                                         goto error;
 562                                 }
 563                                 uevent->enabled = 0;
 564                                 continue;
 565                         }
 566                 }
 567
 568                 free(events);
 569                 break;
 570         }
 571 #if 0
 572         case LTTNG_DOMAIN_UST_EXEC_NAME:
 573         case LTTNG_DOMAIN_UST_PID:
 574         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 575 #endif
 576         default:
 577                 ret = LTTCOMM_UND;
 578                 goto error;
 579         }
 580
 581         return LTTCOMM_OK;
 582
 583 error:
 584         free(events);
 585         return ret;
 586 }