src/qos.c

   1 /*
   2  * Copyright (c) 2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include "internal.h"
  25
  26 #include <_simple.h>
  27 #include <mach/mach_vm.h>
  28 #include <unistd.h>
  29 #include <spawn.h>
  30 #include <spawn_private.h>
  31 #include <sys/spawn_internal.h>
  32 #include <sys/ulock.h>
  33
  34 // TODO: remove me when internal.h can include *_private.h itself
  35 #include "workqueue_private.h"
  36 #include "qos_private.h"
  37
  38 #define PTHREAD_OVERRIDE_SIGNATURE      (0x6f766572)
  39 #define PTHREAD_OVERRIDE_SIG_DEAD       (0x7265766f)
  40
  41 struct pthread_override_s
  42 {
  43         uint32_t sig;
  44         mach_port_t kthread;
  45         pthread_t pthread;
  46         pthread_priority_t priority;
  47         bool malloced;
  48 };
  49
  50 thread_qos_t
  51 _pthread_qos_class_to_thread_qos(qos_class_t qos)
  52 {
  53         switch (qos) {
  54         case QOS_CLASS_USER_INTERACTIVE: return THREAD_QOS_USER_INTERACTIVE;
  55         case QOS_CLASS_USER_INITIATED: return THREAD_QOS_USER_INITIATED;
  56         case QOS_CLASS_DEFAULT: return THREAD_QOS_LEGACY;
  57         case QOS_CLASS_UTILITY: return THREAD_QOS_UTILITY;
  58         case QOS_CLASS_BACKGROUND: return THREAD_QOS_BACKGROUND;
  59         case QOS_CLASS_MAINTENANCE: return THREAD_QOS_MAINTENANCE;
  60         default: return THREAD_QOS_UNSPECIFIED;
  61         }
  62 }
  63
  64 static inline qos_class_t
  65 _pthread_qos_class_from_thread_qos(thread_qos_t tqos)
  66 {
  67         static const qos_class_t thread_qos_to_qos_class[THREAD_QOS_LAST] = {
  68                 [THREAD_QOS_UNSPECIFIED]      = QOS_CLASS_UNSPECIFIED,
  69                 [THREAD_QOS_MAINTENANCE]      = QOS_CLASS_MAINTENANCE,
  70                 [THREAD_QOS_BACKGROUND]       = QOS_CLASS_BACKGROUND,
  71                 [THREAD_QOS_UTILITY]          = QOS_CLASS_UTILITY,
  72                 [THREAD_QOS_LEGACY]           = QOS_CLASS_DEFAULT,
  73                 [THREAD_QOS_USER_INITIATED]   = QOS_CLASS_USER_INITIATED,
  74                 [THREAD_QOS_USER_INTERACTIVE] = QOS_CLASS_USER_INTERACTIVE,
  75         };
  76         if (os_unlikely(tqos >= THREAD_QOS_LAST)) return QOS_CLASS_UNSPECIFIED;
  77         return thread_qos_to_qos_class[tqos];
  78 }
  79
  80 static inline thread_qos_t
  81 _pthread_validate_qos_class_and_relpri(qos_class_t qc, int relpri)
  82 {
  83         if (relpri > 0 || relpri < QOS_MIN_RELATIVE_PRIORITY) {
  84                 return THREAD_QOS_UNSPECIFIED;
  85         }
  86         return _pthread_qos_class_to_thread_qos(qc);
  87 }
  88
  89 static inline void
  90 _pthread_priority_split(pthread_priority_t pp, qos_class_t *qc, int *relpri)
  91 {
  92         thread_qos_t qos = _pthread_priority_thread_qos(pp);
  93         if (qc) *qc = _pthread_qos_class_from_thread_qos(qos);
  94         if (relpri) *relpri = _pthread_priority_relpri(pp);
  95 }
  96
  97 void
  98 _pthread_set_main_qos(pthread_priority_t qos)
  99 {
 100         _main_qos = (uint32_t)qos;
 101 }
 102
 103 int
 104 pthread_attr_set_qos_class_np(pthread_attr_t *attr, qos_class_t qc, int relpri)
 105 {
 106         thread_qos_t qos = _pthread_validate_qos_class_and_relpri(qc, relpri);
 107         if (attr->sig != _PTHREAD_ATTR_SIG || attr->schedset) {
 108                 return EINVAL;
 109         }
 110
 111         attr->qosclass = _pthread_priority_make_from_thread_qos(qos, relpri, 0);
 112         attr->qosset = 1;
 113         attr->schedset = 0;
 114         return 0;
 115 }
 116
 117 int
 118 pthread_attr_get_qos_class_np(pthread_attr_t *attr, qos_class_t *qc, int *relpri)
 119 {
 120         if (attr->sig != _PTHREAD_ATTR_SIG) {
 121                 return EINVAL;
 122         }
 123
 124         _pthread_priority_split(attr->qosset ? attr->qosclass : 0, qc, relpri);
 125         return 0;
 126 }
 127
 128 int
 129 pthread_set_qos_class_self_np(qos_class_t qc, int relpri)
 130 {
 131         thread_qos_t qos = _pthread_validate_qos_class_and_relpri(qc, relpri);
 132         if (!qos) {
 133                 return EINVAL;
 134         }
 135
 136         pthread_priority_t pp = _pthread_priority_make_from_thread_qos(qos, relpri, 0);
 137         return _pthread_set_properties_self(_PTHREAD_SET_SELF_QOS_FLAG, pp, 0);
 138 }
 139
 140 int
 141 pthread_set_qos_class_np(pthread_t thread, qos_class_t qc, int relpri)
 142 {
 143         if (thread != pthread_self()) {
 144                 /* The kext now enforces this anyway, if we check here too, it allows us to call
 145                  * _pthread_set_properties_self later if we can.
 146                  */
 147                 return EPERM;
 148         }
 149         return pthread_set_qos_class_self_np(qc, relpri);
 150 }
 151
 152 int
 153 pthread_get_qos_class_np(pthread_t thread, qos_class_t *qc, int *relpri)
 154 {
 155         pthread_priority_t pp = thread->tsd[_PTHREAD_TSD_SLOT_PTHREAD_QOS_CLASS];
 156         _pthread_priority_split(pp, qc, relpri);
 157         return 0;
 158 }
 159
 160 qos_class_t
 161 qos_class_self(void)
 162 {
 163         pthread_priority_t pp;
 164         pp = _pthread_getspecific_direct(_PTHREAD_TSD_SLOT_PTHREAD_QOS_CLASS);
 165         return _pthread_qos_class_from_thread_qos(_pthread_priority_thread_qos(pp));
 166 }
 167
 168 qos_class_t
 169 qos_class_main(void)
 170 {
 171         pthread_priority_t pp = _main_qos;
 172         return _pthread_qos_class_from_thread_qos(_pthread_priority_thread_qos(pp));
 173 }
 174
 175 pthread_priority_t
 176 _pthread_qos_class_encode(qos_class_t qc, int relpri, unsigned long flags)
 177 {
 178         thread_qos_t qos = _pthread_qos_class_to_thread_qos(qc);
 179         return _pthread_priority_make_from_thread_qos(qos, relpri, flags);
 180 }
 181
 182 qos_class_t
 183 _pthread_qos_class_decode(pthread_priority_t pp, int *relpri, unsigned long *flags)
 184 {
 185         qos_class_t qc;
 186         _pthread_priority_split(pp, &qc, relpri);
 187         if (flags) *flags = (pp & _PTHREAD_PRIORITY_FLAGS_MASK);
 188         return qc;
 189 }
 190
 191 // Encode a legacy workqueue API priority into a pthread_priority_t. This API
 192 // is deprecated and can be removed when the simulator no longer uses it.
 193 pthread_priority_t
 194 _pthread_qos_class_encode_workqueue(int queue_priority, unsigned long flags)
 195 {
 196         thread_qos_t qos;
 197         switch (queue_priority) {
 198         case WORKQ_HIGH_PRIOQUEUE:      qos = THREAD_QOS_USER_INTERACTIVE; break;
 199         case WORKQ_DEFAULT_PRIOQUEUE:   qos = THREAD_QOS_LEGACY; break;
 200         case WORKQ_NON_INTERACTIVE_PRIOQUEUE:
 201         case WORKQ_LOW_PRIOQUEUE:       qos = THREAD_QOS_UTILITY; break;
 202         case WORKQ_BG_PRIOQUEUE:        qos = THREAD_QOS_BACKGROUND; break;
 203         default:
 204                 __pthread_abort();
 205         }
 206         return _pthread_priority_make_from_thread_qos(qos, 0, flags);
 207 }
 208
 209 #define _PTHREAD_SET_SELF_OUTSIDE_QOS_SKIP \
 210                 (_PTHREAD_SET_SELF_QOS_FLAG | _PTHREAD_SET_SELF_FIXEDPRIORITY_FLAG | \
 211                  _PTHREAD_SET_SELF_TIMESHARE_FLAG)
 212
 213 int
 214 _pthread_set_properties_self(_pthread_set_flags_t flags,
 215                 pthread_priority_t priority, mach_port_t voucher)
 216 {
 217         pthread_t self = pthread_self();
 218         _pthread_set_flags_t kflags = flags;
 219         int rv = 0;
 220
 221         if (self->wqoutsideqos && (flags & _PTHREAD_SET_SELF_OUTSIDE_QOS_SKIP)) {
 222                 // A number of properties cannot be altered if we are a workloop
 223                 // thread that has outside of QoS properties applied to it.
 224                 kflags &= ~_PTHREAD_SET_SELF_OUTSIDE_QOS_SKIP;
 225                 if (kflags == 0) goto skip;
 226         }
 227
 228         rv = __bsdthread_ctl(BSDTHREAD_CTL_SET_SELF, priority, voucher, kflags);
 229
 230 skip:
 231          // Set QoS TSD if we succeeded, or only failed the voucher portion of the
 232          // call. Additionally, if we skipped setting QoS because of outside-of-QoS
 233          // attributes then we still want to set the TSD in userspace.
 234         if ((flags & _PTHREAD_SET_SELF_QOS_FLAG) != 0) {
 235                 if (rv == 0 || errno == ENOENT) {
 236                         _pthread_setspecific_direct(_PTHREAD_TSD_SLOT_PTHREAD_QOS_CLASS,
 237                                         priority);
 238                 }
 239         }
 240
 241         if (rv) {
 242                 rv = errno;
 243         }
 244         return rv;
 245 }
 246
 247 int
 248 pthread_set_fixedpriority_self(void)
 249 {
 250         return _pthread_set_properties_self(_PTHREAD_SET_SELF_FIXEDPRIORITY_FLAG, 0, 0);
 251 }
 252
 253 int
 254 pthread_set_timeshare_self(void)
 255 {
 256         return _pthread_set_properties_self(_PTHREAD_SET_SELF_TIMESHARE_FLAG, 0, 0);
 257 }
 258
 259 pthread_override_t
 260 pthread_override_qos_class_start_np(pthread_t thread,  qos_class_t qc, int relpri)
 261 {
 262         pthread_override_t rv;
 263         kern_return_t kr;
 264         thread_qos_t qos;
 265         int res = 0;
 266
 267         /* For now, we don't have access to malloc. So we'll have to vm_allocate this, which means the tiny struct is going
 268          * to use an entire page.
 269          */
 270         bool did_malloc = true;
 271
 272         qos = _pthread_validate_qos_class_and_relpri(qc, relpri);
 273         if (qos == THREAD_QOS_UNSPECIFIED) {
 274                 return (_Nonnull pthread_override_t)NULL;
 275         }
 276
 277         mach_vm_address_t vm_addr = malloc(sizeof(struct pthread_override_s));
 278         if (!vm_addr) {
 279                 vm_addr = vm_page_size;
 280                 did_malloc = false;
 281
 282                 kr = mach_vm_allocate(mach_task_self(), &vm_addr,
 283                                 round_page(sizeof(struct pthread_override_s)),
 284                                 VM_MAKE_TAG(VM_MEMORY_LIBDISPATCH) | VM_FLAGS_ANYWHERE);
 285                 if (kr != KERN_SUCCESS) {
 286                         errno = ENOMEM;
 287                         return (_Nonnull pthread_override_t)NULL;
 288                 }
 289         }
 290
 291         rv = (pthread_override_t)vm_addr;
 292         rv->sig = PTHREAD_OVERRIDE_SIGNATURE;
 293         rv->pthread = thread;
 294         rv->kthread = pthread_mach_thread_np(thread);
 295         rv->priority = _pthread_priority_make_from_thread_qos(qos, relpri, 0);
 296         rv->malloced = did_malloc;
 297
 298         /* To ensure that the kernel port that we keep stays valid, we retain it here. */
 299         kr = mach_port_mod_refs(mach_task_self(), rv->kthread, MACH_PORT_RIGHT_SEND, 1);
 300         if (kr != KERN_SUCCESS) {
 301                 res = EINVAL;
 302         }
 303
 304         if (res == 0) {
 305                 res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_OVERRIDE_START, rv->kthread, rv->priority, (uintptr_t)rv);
 306
 307                 if (res != 0) {
 308                         mach_port_mod_refs(mach_task_self(), rv->kthread, MACH_PORT_RIGHT_SEND, -1);
 309                 }
 310         }
 311
 312         if (res != 0) {
 313                 if (did_malloc) {
 314                         free(rv);
 315                 } else {
 316                         mach_vm_deallocate(mach_task_self(), vm_addr, round_page(sizeof(struct pthread_override_s)));
 317                 }
 318                 rv = NULL;
 319         }
 320         return (_Nonnull pthread_override_t)rv;
 321 }
 322
 323 int
 324 pthread_override_qos_class_end_np(pthread_override_t override)
 325 {
 326         kern_return_t kr;
 327         int res = 0;
 328
 329         /* Double-free is a fault. Swap the signature and check the old one. */
 330         if (_pthread_atomic_xchg_uint32_relaxed(&override->sig, PTHREAD_OVERRIDE_SIG_DEAD) != PTHREAD_OVERRIDE_SIGNATURE) {
 331                 __builtin_trap();
 332         }
 333
 334         /* Always consumes (and deallocates) the pthread_override_t object given. */
 335         res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_OVERRIDE_END, override->kthread, (uintptr_t)override, 0);
 336         if (res == -1) { res = errno; }
 337
 338         /* EFAULT from the syscall means we underflowed. Crash here. */
 339         if (res == EFAULT) {
 340                 // <rdar://problem/17645082> Disable the trap-on-underflow, it doesn't co-exist
 341                 // with dispatch resetting override counts on threads.
 342                 //__builtin_trap();
 343                 res = 0;
 344         }
 345
 346         kr = mach_port_mod_refs(mach_task_self(), override->kthread, MACH_PORT_RIGHT_SEND, -1);
 347         if (kr != KERN_SUCCESS) {
 348                 res = EINVAL;
 349         }
 350
 351         if (override->malloced) {
 352                 free(override);
 353         } else {
 354                 kr = mach_vm_deallocate(mach_task_self(), (mach_vm_address_t)override, round_page(sizeof(struct pthread_override_s)));
 355                 if (kr != KERN_SUCCESS) {
 356                         res = EINVAL;
 357                 }
 358         }
 359
 360         return res;
 361 }
 362
 363 int
 364 _pthread_qos_override_start_direct(mach_port_t thread, pthread_priority_t priority, void *resource)
 365 {
 366         int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_OVERRIDE_START, thread, priority, (uintptr_t)resource);
 367         if (res == -1) { res = errno; }
 368         return res;
 369 }
 370
 371 int
 372 _pthread_qos_override_end_direct(mach_port_t thread, void *resource)
 373 {
 374         int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_OVERRIDE_END, thread, (uintptr_t)resource, 0);
 375         if (res == -1) { res = errno; }
 376         return res;
 377 }
 378
 379 int
 380 _pthread_override_qos_class_start_direct(mach_port_t thread, pthread_priority_t priority)
 381 {
 382         // use pthread_self as the default per-thread memory allocation to track the override in the kernel
 383         return _pthread_qos_override_start_direct(thread, priority, pthread_self());
 384 }
 385
 386 int
 387 _pthread_override_qos_class_end_direct(mach_port_t thread)
 388 {
 389         // use pthread_self as the default per-thread memory allocation to track the override in the kernel
 390         return _pthread_qos_override_end_direct(thread, pthread_self());
 391 }
 392
 393 int
 394 _pthread_workqueue_override_start_direct(mach_port_t thread, pthread_priority_t priority)
 395 {
 396         int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_OVERRIDE_DISPATCH, thread, priority, 0);
 397         if (res == -1) { res = errno; }
 398         return res;
 399 }
 400
 401 int
 402 _pthread_workqueue_override_start_direct_check_owner(mach_port_t thread, pthread_priority_t priority, mach_port_t *ulock_addr)
 403 {
 404 #if !TARGET_OS_IPHONE
 405         static boolean_t kernel_supports_owner_check = TRUE;
 406         if (!kernel_supports_owner_check) {
 407                 ulock_addr = NULL;
 408         }
 409 #endif
 410
 411         for (;;) {
 412                 int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_OVERRIDE_DISPATCH, thread, priority, ulock_addr);
 413                 if (res == -1) { res = errno; }
 414 #if !TARGET_OS_IPHONE
 415                 if (ulock_addr && res == EINVAL) {
 416                         if ((uintptr_t)ulock_addr % _Alignof(_Atomic uint32_t)) {
 417                                 // do not mute bad ulock addresses related errors
 418                                 return EINVAL;
 419                         }
 420                         // backward compatibility for the XBS chroot
 421                         // BSDTHREAD_CTL_QOS_OVERRIDE_DISPATCH used to return EINVAL if
 422                         // arg3 was non NULL.
 423                         kernel_supports_owner_check = FALSE;
 424                         ulock_addr = NULL;
 425                         continue;
 426                 }
 427 #endif
 428                 if (ulock_addr && res == EFAULT) {
 429                         // kernel wants us to redrive the call, so while we refault the
 430                         // memory, also revalidate the owner
 431                         uint32_t uval = *(uint32_t volatile *)ulock_addr;
 432                         if (ulock_owner_value_to_port_name(uval) != thread) {
 433                                 return ESTALE;
 434                         }
 435                         continue;
 436                 }
 437
 438                 return res;
 439         }
 440 }
 441
 442 int
 443 _pthread_workqueue_override_reset(void)
 444 {
 445         int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_OVERRIDE_RESET, 0, 0, 0);
 446         if (res == -1) { res = errno; }
 447         return res;
 448 }
 449
 450 int
 451 _pthread_workqueue_asynchronous_override_add(mach_port_t thread, pthread_priority_t priority, void *resource)
 452 {
 453         int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_DISPATCH_ASYNCHRONOUS_OVERRIDE_ADD, thread, priority, (uintptr_t)resource);
 454         if (res == -1) { res = errno; }
 455         return res;
 456 }
 457
 458 int
 459 _pthread_workqueue_asynchronous_override_reset_self(void *resource)
 460 {
 461         int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_DISPATCH_ASYNCHRONOUS_OVERRIDE_RESET,
 462                                                           0 /* !reset_all */,
 463                                                           (uintptr_t)resource,
 464                                                           0);
 465         if (res == -1) { res = errno; }
 466         return res;
 467 }
 468
 469 int
 470 _pthread_workqueue_asynchronous_override_reset_all_self(void)
 471 {
 472         int res = __bsdthread_ctl(BSDTHREAD_CTL_QOS_DISPATCH_ASYNCHRONOUS_OVERRIDE_RESET,
 473                                                           1 /* reset_all */,
 474                                                           0,
 475                                                           0);
 476         if (res == -1) { res = errno; }
 477         return res;
 478 }
 479
 480 static inline uint16_t
 481 _pthread_workqueue_parallelism_for_priority(int qos, unsigned long flags)
 482 {
 483         int rc = __bsdthread_ctl(BSDTHREAD_CTL_QOS_MAX_PARALLELISM, qos, flags, 0);
 484         if (os_unlikely(rc == -1)) {
 485                 rc = errno;
 486                 if (rc != EINVAL) {
 487                         PTHREAD_INTERNAL_CRASH(rc, "qos_max_parallelism failed");
 488                 }
 489                 if (flags & _PTHREAD_QOS_PARALLELISM_COUNT_LOGICAL) {
 490                         return *(uint8_t *)_COMM_PAGE_LOGICAL_CPUS;
 491                 } else {
 492                         return *(uint8_t *)_COMM_PAGE_PHYSICAL_CPUS;
 493                 }
 494         }
 495         return (uint16_t)rc;
 496 }
 497
 498 int
 499 pthread_qos_max_parallelism(qos_class_t qos, unsigned long flags)
 500 {
 501         thread_qos_t thread_qos;
 502         if (qos == QOS_CLASS_UNSPECIFIED) {
 503                 qos = QOS_CLASS_DEFAULT; // <rdar://problem/35080198>
 504         }
 505         thread_qos = _pthread_qos_class_to_thread_qos(qos);
 506         if (thread_qos == THREAD_QOS_UNSPECIFIED) {
 507                 errno = EINVAL;
 508                 return -1;
 509         }
 510
 511         unsigned long syscall_flags = _PTHREAD_QOS_PARALLELISM_COUNT_LOGICAL;
 512         uint16_t *ptr = &_pthread_globals()->qmp_logical[thread_qos];
 513
 514         if (flags & PTHREAD_MAX_PARALLELISM_PHYSICAL) {
 515                 syscall_flags = 0;
 516                 ptr = &_pthread_globals()->qmp_physical[thread_qos];
 517         }
 518         if (*ptr == 0) {
 519                 *ptr = _pthread_workqueue_parallelism_for_priority(thread_qos, syscall_flags);
 520         }
 521         return *ptr;
 522 }
 523
 524 int
 525 pthread_time_constraint_max_parallelism(unsigned long flags)
 526 {
 527         unsigned long syscall_flags = _PTHREAD_QOS_PARALLELISM_COUNT_LOGICAL;
 528         uint16_t *ptr = &_pthread_globals()->qmp_logical[0];
 529
 530         if (flags & PTHREAD_MAX_PARALLELISM_PHYSICAL) {
 531                 syscall_flags = 0;
 532                 ptr = &_pthread_globals()->qmp_physical[0];
 533         }
 534         if (*ptr == 0) {
 535                 *ptr = _pthread_workqueue_parallelism_for_priority(0,
 536                                 syscall_flags | _PTHREAD_QOS_PARALLELISM_REALTIME);
 537         }
 538         return *ptr;
 539 }
 540
 541 int
 542 posix_spawnattr_set_qos_class_np(posix_spawnattr_t * __restrict __attr, qos_class_t __qos_class)
 543 {
 544         switch (__qos_class) {
 545                 case QOS_CLASS_UTILITY:
 546                         return posix_spawnattr_set_qos_clamp_np(__attr, POSIX_SPAWN_PROC_CLAMP_UTILITY);
 547                 case QOS_CLASS_BACKGROUND:
 548                         return posix_spawnattr_set_qos_clamp_np(__attr, POSIX_SPAWN_PROC_CLAMP_BACKGROUND);
 549                 case QOS_CLASS_MAINTENANCE:
 550                         return posix_spawnattr_set_qos_clamp_np(__attr, POSIX_SPAWN_PROC_CLAMP_MAINTENANCE);
 551                 default:
 552                         return EINVAL;
 553         }
 554 }
 555
 556 int
 557 posix_spawnattr_get_qos_class_np(const posix_spawnattr_t *__restrict __attr, qos_class_t * __restrict __qos_class)
 558 {
 559         uint64_t clamp;
 560
 561         if (!__qos_class) {
 562                 return EINVAL;
 563         }
 564
 565         int rv = posix_spawnattr_get_qos_clamp_np(__attr, &clamp);
 566         if (rv != 0) {
 567                 return rv;
 568         }
 569
 570         switch (clamp) {
 571                 case POSIX_SPAWN_PROC_CLAMP_UTILITY:
 572                         *__qos_class = QOS_CLASS_UTILITY;
 573                         break;
 574                 case POSIX_SPAWN_PROC_CLAMP_BACKGROUND:
 575                         *__qos_class = QOS_CLASS_BACKGROUND;
 576                         break;
 577                 case POSIX_SPAWN_PROC_CLAMP_MAINTENANCE:
 578                         *__qos_class = QOS_CLASS_MAINTENANCE;
 579                         break;
 580                 default:
 581                         *__qos_class = QOS_CLASS_UNSPECIFIED;
 582                         break;
 583         }
 584
 585         return 0;
 586 }