src/introspection.c

   1 /*
   2  * Copyright (c) 2012-2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 // Contains introspection routines that only exist in the version of the
  22 // library with introspection support
  23
  24 #if DISPATCH_INTROSPECTION
  25
  26 #include "internal.h"
  27 #include "dispatch/introspection.h"
  28 #include "introspection_private.h"
  29
  30 typedef struct dispatch_introspection_thread_s {
  31         void *dit_isa;
  32         TAILQ_ENTRY(dispatch_introspection_thread_s) dit_list;
  33         pthread_t thread;
  34         dispatch_queue_t *queue;
  35 } dispatch_introspection_thread_s;
  36 typedef struct dispatch_introspection_thread_s *dispatch_introspection_thread_t;
  37
  38 static TAILQ_HEAD(, dispatch_introspection_thread_s)
  39                 _dispatch_introspection_threads =
  40                 TAILQ_HEAD_INITIALIZER(_dispatch_introspection_threads);
  41 static volatile OSSpinLock _dispatch_introspection_threads_lock;
  42
  43 static void _dispatch_introspection_thread_remove(void *ctxt);
  44
  45 static TAILQ_HEAD(, dispatch_queue_s) _dispatch_introspection_queues =
  46                 TAILQ_HEAD_INITIALIZER(_dispatch_introspection_queues);
  47 static volatile OSSpinLock _dispatch_introspection_queues_lock;
  48
  49 static ptrdiff_t _dispatch_introspection_thread_queue_offset;
  50
  51 #pragma mark -
  52 #pragma mark dispatch_introspection_init
  53
  54 void
  55 _dispatch_introspection_init(void)
  56 {
  57         TAILQ_INSERT_TAIL(&_dispatch_introspection_queues,
  58                         &_dispatch_main_q, diq_list);
  59         TAILQ_INSERT_TAIL(&_dispatch_introspection_queues,
  60                         &_dispatch_mgr_q, diq_list);
  61 #if DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES
  62         TAILQ_INSERT_TAIL(&_dispatch_introspection_queues,
  63                         _dispatch_mgr_q.do_targetq, diq_list);
  64 #endif
  65         for (size_t i = 0; i < DISPATCH_ROOT_QUEUE_COUNT; i++) {
  66                 TAILQ_INSERT_TAIL(&_dispatch_introspection_queues,
  67                                 &_dispatch_root_queues[i], diq_list);
  68         }
  69
  70         // Hack to determine queue TSD offset from start of pthread structure
  71         uintptr_t thread = _dispatch_thread_self();
  72         thread_identifier_info_data_t tiid;
  73         mach_msg_type_number_t cnt = THREAD_IDENTIFIER_INFO_COUNT;
  74         kern_return_t kr = thread_info(pthread_mach_thread_np((void*)thread),
  75                         THREAD_IDENTIFIER_INFO, (thread_info_t)&tiid, &cnt);
  76         if (!dispatch_assume_zero(kr)) {
  77                 _dispatch_introspection_thread_queue_offset =
  78                                 (void*)(uintptr_t)tiid.dispatch_qaddr - (void*)thread;
  79         }
  80         _dispatch_thread_key_create(&dispatch_introspection_key,
  81                         _dispatch_introspection_thread_remove);
  82         _dispatch_introspection_thread_add(); // add main thread
  83 }
  84
  85 const struct dispatch_introspection_versions_s
  86 dispatch_introspection_versions = {
  87         .introspection_version = 1,
  88         .hooks_version = 2,
  89         .hooks_size = sizeof(dispatch_introspection_hooks_s),
  90         .queue_item_version = 1,
  91         .queue_item_size = sizeof(dispatch_introspection_queue_item_s),
  92         .queue_block_version = 1,
  93         .queue_block_size = sizeof(dispatch_introspection_queue_block_s),
  94         .queue_function_version = 1,
  95         .queue_function_size = sizeof(dispatch_introspection_queue_function_s),
  96         .queue_thread_version = 1,
  97         .queue_thread_size = sizeof(dispatch_introspection_queue_thread_s),
  98         .object_version = 1,
  99         .object_size = sizeof(dispatch_introspection_object_s),
 100         .queue_version = 1,
 101         .queue_size = sizeof(dispatch_introspection_queue_s),
 102         .source_version = 1,
 103         .source_size = sizeof(dispatch_introspection_source_s),
 104 };
 105
 106 #pragma mark -
 107 #pragma mark dispatch_introspection_threads
 108
 109 void
 110 _dispatch_introspection_thread_add(void)
 111 {
 112         if (_dispatch_thread_getspecific(dispatch_introspection_key)) {
 113                 return;
 114         }
 115         uintptr_t thread = _dispatch_thread_self();
 116         dispatch_introspection_thread_t dit = (void*)_dispatch_continuation_alloc();
 117         dit->dit_isa = (void*)0x41;
 118         dit->thread = (void*)thread;
 119         dit->queue = !_dispatch_introspection_thread_queue_offset ? NULL :
 120                         (void*)thread + _dispatch_introspection_thread_queue_offset;
 121         _dispatch_thread_setspecific(dispatch_introspection_key, dit);
 122         OSSpinLockLock(&_dispatch_introspection_threads_lock);
 123         TAILQ_INSERT_TAIL(&_dispatch_introspection_threads, dit, dit_list);
 124         OSSpinLockUnlock(&_dispatch_introspection_threads_lock);
 125 }
 126
 127 static void
 128 _dispatch_introspection_thread_remove(void *ctxt)
 129 {
 130         dispatch_introspection_thread_t dit = ctxt;
 131         OSSpinLockLock(&_dispatch_introspection_threads_lock);
 132         TAILQ_REMOVE(&_dispatch_introspection_threads, dit, dit_list);
 133         OSSpinLockUnlock(&_dispatch_introspection_threads_lock);
 134         _dispatch_continuation_free((void*)dit);
 135         _dispatch_thread_setspecific(dispatch_introspection_key, NULL);
 136 }
 137
 138 #pragma mark -
 139 #pragma mark dispatch_introspection_info
 140
 141 static inline
 142 dispatch_introspection_queue_function_s
 143 _dispatch_introspection_continuation_get_info(dispatch_queue_t dq,
 144                 dispatch_continuation_t dc, unsigned long *type)
 145 {
 146         void *ctxt = dc->dc_ctxt;
 147         dispatch_function_t func = dc->dc_func;
 148         pthread_t waiter = NULL;
 149         bool apply = false;
 150         long flags = (long)dc->do_vtable;
 151         if (flags & DISPATCH_OBJ_SYNC_SLOW_BIT) {
 152                 waiter = pthread_from_mach_thread_np((mach_port_t)dc->dc_data);
 153                 if (flags & DISPATCH_OBJ_BARRIER_BIT) {
 154                         dc = dc->dc_ctxt;
 155                         dq = dc->dc_data;
 156                 }
 157                 ctxt = dc->dc_ctxt;
 158                 func = dc->dc_func;
 159         }
 160         if (func == _dispatch_sync_recurse_invoke) {
 161                 dc = dc->dc_ctxt;
 162                 dq = dc->dc_data;
 163                 ctxt = dc->dc_ctxt;
 164                 func = dc->dc_func;
 165         } else if (func == _dispatch_async_redirect_invoke) {
 166                 dq = dc->dc_data;
 167                 dc = dc->dc_other;
 168                 ctxt = dc->dc_ctxt;
 169                 func = dc->dc_func;
 170                 flags = (long)dc->do_vtable;
 171         } else if (func == _dispatch_mach_barrier_invoke) {
 172                 dq = dq->do_targetq;
 173                 ctxt = dc->dc_data;
 174                 func = dc->dc_other;
 175         } else if (func == _dispatch_apply_invoke ||
 176                         func == _dispatch_apply_redirect_invoke) {
 177                 dispatch_apply_t da = ctxt;
 178                 if (da->da_todo) {
 179                         dc = da->da_dc;
 180                         if (func == _dispatch_apply_redirect_invoke) {
 181                                 dq = dc->dc_data;
 182                         }
 183                         ctxt = dc->dc_ctxt;
 184                         func = dc->dc_func;
 185                         apply = true;
 186                 }
 187         }
 188         if (func == _dispatch_call_block_and_release) {
 189                 *type = dispatch_introspection_queue_item_type_block;
 190                 func = _dispatch_Block_invoke(ctxt);
 191         } else {
 192                 *type = dispatch_introspection_queue_item_type_function;
 193         }
 194         dispatch_introspection_queue_function_s diqf= {
 195                 .continuation = dc,
 196                 .target_queue = dq,
 197                 .context = ctxt,
 198                 .function = func,
 199                 .group = flags & DISPATCH_OBJ_GROUP_BIT ? dc->dc_data : NULL,
 200                 .waiter = waiter,
 201                 .barrier = flags & DISPATCH_OBJ_BARRIER_BIT,
 202                 .sync = flags & DISPATCH_OBJ_SYNC_SLOW_BIT,
 203                 .apply = apply,
 204         };
 205         return diqf;
 206 }
 207
 208 static inline
 209 dispatch_introspection_object_s
 210 _dispatch_introspection_object_get_info(dispatch_object_t dou)
 211 {
 212         dispatch_introspection_object_s dio = {
 213                 .object = dou._dc,
 214                 .target_queue = dou._do->do_targetq,
 215                 .type = (void*)dou._do->do_vtable,
 216                 .kind = dx_kind(dou._do),
 217         };
 218         return dio;
 219 }
 220
 221 DISPATCH_USED inline
 222 dispatch_introspection_queue_s
 223 dispatch_introspection_queue_get_info(dispatch_queue_t dq)
 224 {
 225         bool global = (dq->do_xref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT) ||
 226                         (dq->do_ref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT);
 227         uint16_t width = dq->dq_width;
 228         if (width > 1 && width != DISPATCH_QUEUE_WIDTH_MAX) width /= 2;
 229         dispatch_introspection_queue_s diq = {
 230                 .queue = dq,
 231                 .target_queue = dq->do_targetq,
 232                 .label = dq->dq_label,
 233                 .serialnum = dq->dq_serialnum,
 234                 .width = width,
 235                 .suspend_count = dq->do_suspend_cnt / 2,
 236                 .enqueued = (dq->do_suspend_cnt & 1) && !global,
 237                 .barrier = (dq->dq_running & 1) && !global,
 238                 .draining = (dq->dq_items_head == (void*)~0ul) ||
 239                                 (!dq->dq_items_head && dq->dq_items_tail),
 240                 .global = global,
 241                 .main = (dq == &_dispatch_main_q),
 242         };
 243         return diq;
 244 }
 245
 246 static inline
 247 dispatch_introspection_source_s
 248 _dispatch_introspection_source_get_info(dispatch_source_t ds)
 249 {
 250         dispatch_source_refs_t dr = ds->ds_refs;
 251         dispatch_continuation_t dc = dr->ds_handler[DS_EVENT_HANDLER];
 252         void *ctxt = NULL;
 253         dispatch_function_t handler = NULL;
 254         bool hdlr_is_block = false;
 255         if (dc) {
 256                 ctxt = dc->dc_ctxt;
 257                 handler = dc->dc_func;
 258                 hdlr_is_block = ((long)dc->do_vtable & DISPATCH_OBJ_BLOCK_RELEASE_BIT);
 259         }
 260         bool after = (handler == _dispatch_after_timer_callback);
 261         if (after && !(ds->ds_atomic_flags & DSF_CANCELED)) {
 262                 dc = ctxt;
 263                 ctxt = dc->dc_ctxt;
 264                 handler = dc->dc_func;
 265                 hdlr_is_block = (handler == _dispatch_call_block_and_release);
 266                 if (hdlr_is_block) {
 267                         handler = _dispatch_Block_invoke(ctxt);
 268                 }
 269         }
 270         dispatch_introspection_source_s dis = {
 271                 .source = ds,
 272                 .target_queue = ds->do_targetq,
 273                 .type = ds->ds_dkev ? (unsigned long)ds->ds_dkev->dk_kevent.filter : 0,
 274                 .handle = ds->ds_dkev ? (unsigned long)ds->ds_dkev->dk_kevent.ident : 0,
 275                 .context = ctxt,
 276                 .handler = handler,
 277                 .suspend_count = ds->do_suspend_cnt / 2,
 278                 .enqueued = (ds->do_suspend_cnt & 1),
 279                 .handler_is_block = hdlr_is_block,
 280                 .timer = ds->ds_is_timer,
 281                 .after = after,
 282         };
 283         return dis;
 284 }
 285
 286 static inline
 287 dispatch_introspection_queue_thread_s
 288 _dispatch_introspection_thread_get_info(dispatch_introspection_thread_t dit)
 289 {
 290         dispatch_introspection_queue_thread_s diqt = {
 291                 .object = (void*)dit,
 292                 .thread = dit->thread,
 293         };
 294         if (dit->queue && *dit->queue) {
 295                 diqt.queue = dispatch_introspection_queue_get_info(*dit->queue);
 296         }
 297         return diqt;
 298 }
 299
 300 DISPATCH_USED inline
 301 dispatch_introspection_queue_item_s
 302 dispatch_introspection_queue_item_get_info(dispatch_queue_t dq,
 303                 dispatch_continuation_t dc)
 304 {
 305         dispatch_introspection_queue_item_s diqi;
 306         if (DISPATCH_OBJ_IS_VTABLE(dc)) {
 307                 dispatch_object_t dou = (dispatch_object_t)dc;
 308                 unsigned long type = dx_type(dou._do);
 309                 unsigned long metatype = type & _DISPATCH_META_TYPE_MASK;
 310                 if (metatype == _DISPATCH_QUEUE_TYPE &&
 311                                 type != DISPATCH_QUEUE_SPECIFIC_TYPE) {
 312                         diqi.type = dispatch_introspection_queue_item_type_queue;
 313                         diqi.queue = dispatch_introspection_queue_get_info(dou._dq);
 314                 } else if (metatype == _DISPATCH_SOURCE_TYPE) {
 315                         diqi.type = dispatch_introspection_queue_item_type_source;
 316                         diqi.source = _dispatch_introspection_source_get_info(dou._ds);
 317                 } else {
 318                         diqi.type = dispatch_introspection_queue_item_type_object;
 319                         diqi.object = _dispatch_introspection_object_get_info(dou._do);
 320                 }
 321         } else {
 322                 diqi.function = _dispatch_introspection_continuation_get_info(dq, dc,
 323                                 &diqi.type);
 324         }
 325         return diqi;
 326 }
 327
 328 #pragma mark -
 329 #pragma mark dispatch_introspection_iterators
 330
 331 DISPATCH_USED
 332 dispatch_queue_t
 333 dispatch_introspection_get_queues(dispatch_queue_t start, size_t count,
 334                 dispatch_introspection_queue_t queues)
 335 {
 336         dispatch_queue_t next;
 337         next = start ? start : TAILQ_FIRST(&_dispatch_introspection_queues);
 338         while (count--) {
 339                 if (!next) {
 340                         queues->queue = NULL;
 341                         break;
 342                 }
 343                 *queues++ = dispatch_introspection_queue_get_info(next);
 344                 next = TAILQ_NEXT(next, diq_list);
 345         }
 346         return next;
 347 }
 348
 349 DISPATCH_USED
 350 dispatch_continuation_t
 351 dispatch_introspection_get_queue_threads(dispatch_continuation_t start,
 352                 size_t count, dispatch_introspection_queue_thread_t threads)
 353 {
 354         dispatch_introspection_thread_t next = start ? (void*)start :
 355                         TAILQ_FIRST(&_dispatch_introspection_threads);
 356         while (count--) {
 357                 if (!next) {
 358                         threads->object = NULL;
 359                         break;
 360                 }
 361                 *threads++ = _dispatch_introspection_thread_get_info(next);
 362                 next = TAILQ_NEXT(next, dit_list);
 363         }
 364         return (void*)next;
 365 }
 366
 367 DISPATCH_USED
 368 dispatch_continuation_t
 369 dispatch_introspection_queue_get_items(dispatch_queue_t dq,
 370                 dispatch_continuation_t start, size_t count,
 371                 dispatch_introspection_queue_item_t items)
 372 {
 373         dispatch_continuation_t next = start ? start :
 374                         dq->dq_items_head == (void*)~0ul ? NULL : (void*)dq->dq_items_head;
 375         while (count--) {
 376                 if (!next) {
 377                         items->type = dispatch_introspection_queue_item_type_none;
 378                         break;
 379                 }
 380                 *items++ = dispatch_introspection_queue_item_get_info(dq, next);
 381                 next = next->do_next;
 382         }
 383         return next;
 384 }
 385
 386 #pragma mark -
 387 #pragma mark dispatch_introspection_hooks
 388
 389 #define DISPATCH_INTROSPECTION_NO_HOOK ((void*)~0ul)
 390
 391 dispatch_introspection_hooks_s _dispatch_introspection_hooks;
 392 dispatch_introspection_hooks_s _dispatch_introspection_hook_callouts;
 393 static const
 394 dispatch_introspection_hooks_s _dispatch_introspection_hook_callouts_enabled = {
 395         .queue_create = DISPATCH_INTROSPECTION_NO_HOOK,
 396         .queue_dispose = DISPATCH_INTROSPECTION_NO_HOOK,
 397         .queue_item_enqueue = DISPATCH_INTROSPECTION_NO_HOOK,
 398         .queue_item_dequeue = DISPATCH_INTROSPECTION_NO_HOOK,
 399         .queue_item_complete = DISPATCH_INTROSPECTION_NO_HOOK,
 400 };
 401
 402 #define DISPATCH_INTROSPECTION_HOOKS_COUNT (( \
 403                 sizeof(_dispatch_introspection_hook_callouts_enabled) - \
 404                 sizeof(_dispatch_introspection_hook_callouts_enabled._reserved)) / \
 405                 sizeof(dispatch_function_t))
 406
 407 #define DISPATCH_INTROSPECTION_HOOK_ENABLED(h) \
 408                 (slowpath(_dispatch_introspection_hooks.h))
 409
 410 #define DISPATCH_INTROSPECTION_HOOK_CALLOUT(h, ...) ({ \
 411                 typeof(_dispatch_introspection_hooks.h) _h; \
 412                 _h = _dispatch_introspection_hooks.h; \
 413                 if (slowpath((void*)(_h) != DISPATCH_INTROSPECTION_NO_HOOK)) { \
 414                         _h(__VA_ARGS__); \
 415                 } })
 416
 417 #define DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(h) \
 418                 DISPATCH_EXPORT void _dispatch_introspection_hook_##h(void) \
 419                 asm("_dispatch_introspection_hook_" #h); \
 420                 void _dispatch_introspection_hook_##h(void) {}
 421
 422 #define DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(h, ...)\
 423                 dispatch_introspection_hook_##h(__VA_ARGS__)
 424
 425 DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(queue_create);
 426 DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(queue_destroy);
 427 DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(queue_item_enqueue);
 428 DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(queue_item_dequeue);
 429 DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(queue_item_complete);
 430 DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(queue_callout_begin);
 431 DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK(queue_callout_end);
 432
 433 DISPATCH_USED
 434 void
 435 dispatch_introspection_hooks_install(dispatch_introspection_hooks_t hooks)
 436 {
 437         dispatch_introspection_hooks_s old_hooks = _dispatch_introspection_hooks;
 438         _dispatch_introspection_hooks = *hooks;
 439         dispatch_function_t *e = (void*)&_dispatch_introspection_hook_callouts,
 440                         *h = (void*)&_dispatch_introspection_hooks, *oh = (void*)&old_hooks;
 441         for (size_t i = 0; i < DISPATCH_INTROSPECTION_HOOKS_COUNT; i++) {
 442                 if (!h[i] && e[i]) {
 443                         h[i] = DISPATCH_INTROSPECTION_NO_HOOK;
 444                 }
 445                 if (oh[i] == DISPATCH_INTROSPECTION_NO_HOOK) {
 446                         oh[i] = NULL;
 447                 }
 448         }
 449         *hooks = old_hooks;
 450 }
 451
 452 DISPATCH_USED
 453 void
 454 dispatch_introspection_hook_callouts_enable(
 455                 dispatch_introspection_hooks_t enable)
 456 {
 457         _dispatch_introspection_hook_callouts = enable ? *enable :
 458                         _dispatch_introspection_hook_callouts_enabled;
 459         dispatch_function_t *e = (void*)&_dispatch_introspection_hook_callouts,
 460                         *h = (void*)&_dispatch_introspection_hooks;
 461         for (size_t i = 0; i < DISPATCH_INTROSPECTION_HOOKS_COUNT; i++) {
 462                 if (e[i] && !h[i]) {
 463                         h[i] = DISPATCH_INTROSPECTION_NO_HOOK;
 464                 } else if (!e[i] && h[i] == DISPATCH_INTROSPECTION_NO_HOOK) {
 465                         h[i] = NULL;
 466                 }
 467         }
 468 }
 469
 470 DISPATCH_NOINLINE
 471 void
 472 dispatch_introspection_hook_callout_queue_create(
 473                 dispatch_introspection_queue_t queue_info)
 474 {
 475         DISPATCH_INTROSPECTION_HOOK_CALLOUT(queue_create, queue_info);
 476 }
 477
 478 DISPATCH_NOINLINE
 479 static void
 480 _dispatch_introspection_queue_create_hook(dispatch_queue_t dq)
 481 {
 482         dispatch_introspection_queue_s diq;
 483         diq = dispatch_introspection_queue_get_info(dq);
 484         dispatch_introspection_hook_callout_queue_create(&diq);
 485 }
 486
 487 dispatch_queue_t
 488 _dispatch_introspection_queue_create(dispatch_queue_t dq)
 489 {
 490         OSSpinLockLock(&_dispatch_introspection_queues_lock);
 491         TAILQ_INSERT_TAIL(&_dispatch_introspection_queues, dq, diq_list);
 492         OSSpinLockUnlock(&_dispatch_introspection_queues_lock);
 493
 494         DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(queue_create, dq);
 495         if (DISPATCH_INTROSPECTION_HOOK_ENABLED(queue_create)) {
 496                 _dispatch_introspection_queue_create_hook(dq);
 497         }
 498         return dq;
 499 }
 500
 501 DISPATCH_NOINLINE
 502 void
 503 dispatch_introspection_hook_callout_queue_dispose(
 504                 dispatch_introspection_queue_t queue_info)
 505 {
 506         DISPATCH_INTROSPECTION_HOOK_CALLOUT(queue_dispose, queue_info);
 507 }
 508
 509 DISPATCH_NOINLINE
 510 static void
 511 _dispatch_introspection_queue_dispose_hook(dispatch_queue_t dq)
 512 {
 513         dispatch_introspection_queue_s diq;
 514         diq = dispatch_introspection_queue_get_info(dq);
 515         dispatch_introspection_hook_callout_queue_dispose(&diq);
 516 }
 517
 518 void
 519 _dispatch_introspection_queue_dispose(dispatch_queue_t dq)
 520 {
 521         DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(queue_destroy, dq);
 522         if (DISPATCH_INTROSPECTION_HOOK_ENABLED(queue_dispose)) {
 523                 _dispatch_introspection_queue_dispose_hook(dq);
 524         }
 525
 526         OSSpinLockLock(&_dispatch_introspection_queues_lock);
 527         TAILQ_REMOVE(&_dispatch_introspection_queues, dq, diq_list);
 528         OSSpinLockUnlock(&_dispatch_introspection_queues_lock);
 529 }
 530
 531 DISPATCH_NOINLINE
 532 void
 533 dispatch_introspection_hook_callout_queue_item_enqueue(dispatch_queue_t queue,
 534                 dispatch_introspection_queue_item_t item)
 535 {
 536         DISPATCH_INTROSPECTION_HOOK_CALLOUT(queue_item_enqueue, queue, item);
 537 }
 538
 539 DISPATCH_NOINLINE
 540 static void
 541 _dispatch_introspection_queue_item_enqueue_hook(dispatch_queue_t dq,
 542                 dispatch_object_t dou)
 543 {
 544         dispatch_introspection_queue_item_s diqi;
 545         diqi = dispatch_introspection_queue_item_get_info(dq, dou._dc);
 546         dispatch_introspection_hook_callout_queue_item_enqueue(dq, &diqi);
 547 }
 548
 549 void
 550 _dispatch_introspection_queue_item_enqueue(dispatch_queue_t dq,
 551                 dispatch_object_t dou)
 552 {
 553         DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(
 554                         queue_item_enqueue, dq, dou);
 555         if (DISPATCH_INTROSPECTION_HOOK_ENABLED(queue_item_enqueue)) {
 556                 _dispatch_introspection_queue_item_enqueue_hook(dq, dou);
 557         }
 558 }
 559
 560 DISPATCH_NOINLINE
 561 void
 562 dispatch_introspection_hook_callout_queue_item_dequeue(dispatch_queue_t queue,
 563                 dispatch_introspection_queue_item_t item)
 564 {
 565         DISPATCH_INTROSPECTION_HOOK_CALLOUT(queue_item_dequeue, queue, item);
 566 }
 567
 568 DISPATCH_NOINLINE
 569 static void
 570 _dispatch_introspection_queue_item_dequeue_hook(dispatch_queue_t dq,
 571                 dispatch_object_t dou)
 572 {
 573         dispatch_introspection_queue_item_s diqi;
 574         diqi = dispatch_introspection_queue_item_get_info(dq, dou._dc);
 575         dispatch_introspection_hook_callout_queue_item_dequeue(dq, &diqi);
 576 }
 577
 578 void
 579 _dispatch_introspection_queue_item_dequeue(dispatch_queue_t dq,
 580                 dispatch_object_t dou)
 581 {
 582         DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(
 583                         queue_item_dequeue, dq, dou);
 584         if (DISPATCH_INTROSPECTION_HOOK_ENABLED(queue_item_dequeue)) {
 585                 _dispatch_introspection_queue_item_dequeue_hook(dq, dou);
 586         }
 587 }
 588
 589 DISPATCH_NOINLINE
 590 void
 591 dispatch_introspection_hook_callout_queue_item_complete(
 592                 dispatch_continuation_t object)
 593 {
 594         DISPATCH_INTROSPECTION_HOOK_CALLOUT(queue_item_complete, object);
 595 }
 596
 597 DISPATCH_NOINLINE
 598 static void
 599 _dispatch_introspection_queue_item_complete_hook(dispatch_object_t dou)
 600 {
 601         dispatch_introspection_hook_callout_queue_item_complete(dou._dc);
 602 }
 603
 604 void
 605 _dispatch_introspection_queue_item_complete(dispatch_object_t dou)
 606 {
 607         DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(queue_item_complete, dou);
 608         if (DISPATCH_INTROSPECTION_HOOK_ENABLED(queue_item_complete)) {
 609                 _dispatch_introspection_queue_item_complete_hook(dou);
 610         }
 611 }
 612
 613 void
 614 _dispatch_introspection_callout_entry(void *ctxt, dispatch_function_t f) {
 615         dispatch_queue_t dq = _dispatch_queue_get_current();
 616         DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(
 617                         queue_callout_begin, dq, ctxt, f);
 618 }
 619
 620 void
 621 _dispatch_introspection_callout_return(void *ctxt, dispatch_function_t f) {
 622         dispatch_queue_t dq = _dispatch_queue_get_current();
 623         DISPATCH_INTROSPECTION_INTERPOSABLE_HOOK_CALLOUT(
 624                         queue_callout_end, dq, ctxt, f);
 625 }
 626
 627 #endif // DISPATCH_INTROSPECTION