Ticket #61115: darwin_compat.c

 /*
  * Source: https://github.com/pktgen/sshfs/blob/master/compat/darwin_compat.c
  * Copyright (c) 2006-2008 Amit Singh/Google Inc.
  * Copyright (c) 2012 Anatol Pomozov
  * Copyright (c) 2011-2013 Benjamin Fleischer
  */

 #include "darwin_compat.h"

 #include <assert.h>
 #include <errno.h>
 #include <sys/types.h>

 /*
  * Semaphore implementation based on:
  *
  * Copyright (C) 2000,02 Free Software Foundation, Inc.
  * This file is part of the GNU C Library.
  * Written by Ga<EB>l Le Mignot <address@hidden>
  *
  * The GNU C Library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
  *
  * The GNU C Library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with the GNU C Library; see the file COPYING.LIB.  If not,
  * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */

 /* Semaphores */

 #define __SEM_ID_NONE  ((int)0x0)
 #define __SEM_ID_LOCAL ((int)0xcafef00d)

 /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_init.html */
 int
 darwin_sem_init(darwin_sem_t *sem, int pshared, unsigned int value)
 {
     if (pshared) {
         errno = ENOSYS;
         return -1;
     }

     sem->id = __SEM_ID_NONE;

     if (pthread_cond_init(&sem->__data.local.count_cond, NULL)) {
         goto cond_init_fail;
     }

     if (pthread_mutex_init(&sem->__data.local.count_lock, NULL)) {
         goto mutex_init_fail;
     }

     sem->__data.local.count = value;
     sem->id = __SEM_ID_LOCAL;

     return 0;

 mutex_init_fail:

     pthread_cond_destroy(&sem->__data.local.count_cond);

 cond_init_fail:

     return -1;
 }

 /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_destroy.html */
 int
 darwin_sem_destroy(darwin_sem_t *sem)
 {
     int res = 0;

     pthread_mutex_lock(&sem->__data.local.count_lock);

     sem->id = __SEM_ID_NONE;
     pthread_cond_broadcast(&sem->__data.local.count_cond);

     if (pthread_cond_destroy(&sem->__data.local.count_cond)) {
         res = -1;
     }

     pthread_mutex_unlock(&sem->__data.local.count_lock);

     if (pthread_mutex_destroy(&sem->__data.local.count_lock)) {
         res = -1;
     }

     return res;
 }

 int
 darwin_sem_getvalue(darwin_sem_t *sem, unsigned int *sval)
 {
     int res = 0;

     pthread_mutex_lock(&sem->__data.local.count_lock);

     if (sem->id != __SEM_ID_LOCAL) {
         res = -1;
         errno = EINVAL;
     } else {
         *sval = sem->__data.local.count;
     }

     pthread_mutex_unlock(&sem->__data.local.count_lock);

     return res;
 }

 /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_post.html */
 int
 darwin_sem_post(darwin_sem_t *sem)
 {
     int res = 0;

     pthread_mutex_lock(&sem->__data.local.count_lock);

     if (sem->id != __SEM_ID_LOCAL) {
         res = -1;
         errno = EINVAL;
     } else if (sem->__data.local.count < DARWIN_SEM_VALUE_MAX) {
         sem->__data.local.count++;
         if (sem->__data.local.count == 1) {
             pthread_cond_signal(&sem->__data.local.count_cond);
         }
     } else {
         errno = ERANGE;
         res = -1;
     }

     pthread_mutex_unlock(&sem->__data.local.count_lock);

     return res;
 }

 /* http://www.opengroup.org/onlinepubs/009695399/functions/sem_timedwait.html */
 int
 darwin_sem_timedwait(darwin_sem_t *sem, const struct timespec *abs_timeout)
 {
     int res = 0;

     if (abs_timeout &&
         (abs_timeout->tv_nsec < 0 || abs_timeout->tv_nsec >= 1000000000)) {
         errno = EINVAL;
         return -1;
     }

     pthread_cleanup_push((void(*)(void*))&pthread_mutex_unlock,
                  &sem->__data.local.count_lock);

     pthread_mutex_lock(&sem->__data.local.count_lock);

     if (sem->id != __SEM_ID_LOCAL) {
         errno = EINVAL;
         res = -1;
     } else {
         if (!sem->__data.local.count) {
             res = pthread_cond_timedwait(&sem->__data.local.count_cond,
                              &sem->__data.local.count_lock,
                              abs_timeout);
         }
         if (res) {
             assert(res == ETIMEDOUT);
             res = -1;
             errno = ETIMEDOUT;
         } else if (sem->id != __SEM_ID_LOCAL) {
             res = -1;
             errno = EINVAL;
         } else {
             sem->__data.local.count--;
         }
     }

     pthread_cleanup_pop(1);

     return res;
 }

 /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_trywait.html */
 int
 darwin_sem_trywait(darwin_sem_t *sem)
 {
     int res = 0;

     pthread_mutex_lock(&sem->__data.local.count_lock);

     if (sem->id != __SEM_ID_LOCAL) {
         res = -1;
         errno = EINVAL;
     } else if (sem->__data.local.count) {
         sem->__data.local.count--;
     } else {
         res = -1;
         errno = EAGAIN;
     }

     pthread_mutex_unlock (&sem->__data.local.count_lock);

     return res;
 }

 /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_wait.html */
 int
 darwin_sem_wait(darwin_sem_t *sem)
 {
     int res = 0;

     pthread_cleanup_push((void(*)(void*))&pthread_mutex_unlock,
                  &sem->__data.local.count_lock);

     pthread_mutex_lock(&sem->__data.local.count_lock);

     if (sem->id != __SEM_ID_LOCAL) {
         errno = EINVAL;
         res = -1;
     } else {
         if (!sem->__data.local.count) {
             pthread_cond_wait(&sem->__data.local.count_cond,
                       &sem->__data.local.count_lock);
             if (!sem->__data.local.count) {
                 /* spurious wakeup, assume it is an interruption */
                 res = -1;
                 errno = EINTR;
                 goto out;
             }
         }
         if (sem->id != __SEM_ID_LOCAL) {
             res = -1;
             errno = EINVAL;
         } else {
             sem->__data.local.count--;
         }
     }

 out:
     pthread_cleanup_pop(1);

     return res;
 }