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 #ifndef __APPLE__
  27 #include "runtime/os.hpp"
  28 // POSIX unamed semaphores are not supported on OS X.
  29 #include "semaphore_posix.hpp"
  30 #include <semaphore.h>
  31 
  32 #define check_with_errno(check_type, cond, msg)                             \
  33   do {                                                                      \
  34     int err = errno;                                                        \
  35     check_type(cond, /*"%s; error='%s' (errno=%s)", */msg/*, os::strerror(err),*/   \
  36                /*os::errno_name(err)*/);                                        \
  37 } while (false)
  38 
  39 #define assert_with_errno(cond, msg)    check_with_errno(assert, cond, msg)
  40 #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
  41 
  42 PosixSemaphore::PosixSemaphore(uint value) {
  43   int ret = sem_init(&_semaphore, 0, value);
  44 
  45   guarantee_with_errno(ret == 0, "Failed to initialize semaphore");
  46 }
  47 
  48 PosixSemaphore::~PosixSemaphore() {
  49   sem_destroy(&_semaphore);
  50 }
  51 
  52 void PosixSemaphore::signal(uint count) {
  53   for (uint i = 0; i < count; i++) {
  54     int ret = sem_post(&_semaphore);
  55 
  56     assert_with_errno(ret == 0, "sem_post failed");
  57   }
  58 }
  59 
  60 void PosixSemaphore::wait() {
  61   int ret;
  62 
  63   do {
  64     ret = sem_wait(&_semaphore);
  65   } while (ret != 0 && errno == EINTR);
  66 
  67   assert_with_errno(ret == 0, "sem_wait failed");
  68 }
  69 
  70 bool PosixSemaphore::trywait() {
  71   int ret;
  72 
  73   do {
  74     ret = sem_trywait(&_semaphore);
  75   } while (ret != 0 && errno == EINTR);
  76 
  77   assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed");
  78 
  79   return ret == 0;
  80 }
  81 
  82 bool PosixSemaphore::timedwait(struct timespec ts) {
  83   while (true) {
  84     int result = sem_timedwait(&_semaphore, &ts);
  85     if (result == 0) {
  86       return true;
  87     } else if (errno == EINTR) {
  88       continue;
  89     } else if (errno == ETIMEDOUT) {
  90       return false;
  91     } else {
  92       assert_with_errno(false, "timedwait failed");
  93       return false;
  94     }
  95   }
  96 }
  97 #endif // __APPLE__
  98