1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled/precompiled.hpp"
  26 #include "semaphore_bsd.hpp"
  27 #include "utilities/debug.hpp"
  28 
  29 #include <semaphore.h>
  30 
  31 #ifdef __APPLE__
  32 // OS X doesn't support unamed POSIX semaphores, so the implementation in os_posix.cpp can't be used.
  33 
  34 static const char* sem_init_strerror(kern_return_t value) {
  35   switch (value) {
  36     case KERN_INVALID_ARGUMENT:  return "Invalid argument";
  37     case KERN_RESOURCE_SHORTAGE: return "Resource shortage";
  38     default:                     return "Unknown";
  39   }
  40 }
  41 
  42 OSXSemaphore::OSXSemaphore(uint value) {
  43   kern_return_t ret = semaphore_create(mach_task_self(), &_semaphore, SYNC_POLICY_FIFO, value);
  44 
  45   guarantee(ret == KERN_SUCCESS, "Failed to create semaphore: %s", sem_init_strerror(ret));
  46 }
  47 
  48 OSXSemaphore::~OSXSemaphore() {
  49   semaphore_destroy(mach_task_self(), _semaphore);
  50 }
  51 
  52 void OSXSemaphore::signal(uint count) {
  53   for (uint i = 0; i < count; i++) {
  54     kern_return_t ret = semaphore_signal(_semaphore);
  55 
  56     assert(ret == KERN_SUCCESS, "Failed to signal semaphore");
  57   }
  58 }
  59 
  60 void OSXSemaphore::wait() {
  61   kern_return_t ret;
  62   while ((ret = semaphore_wait(_semaphore)) == KERN_ABORTED) {
  63     // Semaphore was interrupted. Retry.
  64   }
  65   assert(ret == KERN_SUCCESS, "Failed to wait on semaphore");
  66 }
  67 
  68 int64_t OSXSemaphore::currenttime() {
  69   struct timeval tv;
  70   gettimeofday(&tv, NULL);
  71   return (tv.tv_sec * NANOSECS_PER_SEC) + (tv.tv_usec * 1000);
  72 }
  73 
  74 bool OSXSemaphore::trywait() {
  75   return timedwait(0, 0);
  76 }
  77 
  78 bool OSXSemaphore::timedwait(unsigned int sec, int nsec) {
  79   kern_return_t kr = KERN_ABORTED;
  80   mach_timespec_t waitspec;
  81   waitspec.tv_sec = sec;
  82   waitspec.tv_nsec = nsec;
  83 
  84   int64_t starttime = currenttime();
  85 
  86   kr = semaphore_timedwait(_semaphore, waitspec);
  87   while (kr == KERN_ABORTED) {
  88     int64_t totalwait = (sec * NANOSECS_PER_SEC) + nsec;
  89 
  90     int64_t current = currenttime();
  91     int64_t passedtime = current - starttime;
  92 
  93     if (passedtime >= totalwait) {
  94       waitspec.tv_sec = 0;
  95       waitspec.tv_nsec = 0;
  96     } else {
  97       int64_t waittime = totalwait - (current - starttime);
  98       waitspec.tv_sec = waittime / NANOSECS_PER_SEC;
  99       waitspec.tv_nsec = waittime % NANOSECS_PER_SEC;
 100     }
 101 
 102     kr = semaphore_timedwait(_semaphore, waitspec);
 103   }
 104 
 105   return kr == KERN_SUCCESS;
 106 }
 107 #endif // __APPLE__