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