src/os/semaphore.c

   1 /*
   2  * Copyright (c) 2008-2013 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 #include "os/internal.h"
  22 #include <mach/mach_init.h>
  23 #include <mach/semaphore.h>
  24 #include <mach/task.h>
  25 #include <mach/thread_switch.h>
  26
  27 #define OS_VERIFY_MIG(x, msg) do { \
  28                 if (unlikely((x) == MIG_REPLY_MISMATCH)) { \
  29                         __LIBPLATFORM_CLIENT_CRASH__(x, msg); \
  30                 } \
  31         } while (0)
  32
  33 #define OS_SEMAPHORE_VERIFY_KR(x, msg) do { \
  34                 if (unlikely(x)) { \
  35                         __LIBPLATFORM_CLIENT_CRASH__(x, msg); \
  36                 } \
  37         } while (0)
  38
  39 os_semaphore_t
  40 _os_semaphore_create(void)
  41 {
  42         semaphore_t s4;
  43         kern_return_t kr;
  44         while (unlikely(kr = semaphore_create(mach_task_self(), &s4,
  45                         SYNC_POLICY_FIFO, 0))) {
  46                 OS_VERIFY_MIG(kr, "Allocating semaphore failed with MIG_REPLY_MISMATCH");
  47                 thread_switch(MACH_PORT_NULL, SWITCH_OPTION_WAIT, 100);
  48         }
  49         return (os_semaphore_t)s4;
  50 }
  51
  52 void
  53 _os_semaphore_dispose(os_semaphore_t sema)
  54 {
  55         semaphore_t s4 = (semaphore_t)sema;
  56         kern_return_t kr = semaphore_destroy(mach_task_self(), s4);
  57         OS_SEMAPHORE_VERIFY_KR(kr, "Destroying semaphore failed");
  58 }
  59
  60 void
  61 _os_semaphore_signal(os_semaphore_t sema)
  62 {
  63         semaphore_t s4 = (semaphore_t)sema;
  64         kern_return_t kr = semaphore_signal(s4);
  65         OS_SEMAPHORE_VERIFY_KR(kr, "Signaling semaphore failed");
  66 }
  67
  68 void
  69 _os_semaphore_wait(os_semaphore_t sema)
  70 {
  71         semaphore_t s4 = (semaphore_t)sema;
  72         kern_return_t kr;
  73         do {
  74                 kr = semaphore_wait(s4);
  75         } while (unlikely(kr == KERN_ABORTED));
  76         OS_SEMAPHORE_VERIFY_KR(kr, "Waiting on semaphore failed");
  77 }