native_client_sdk/src/libraries/third_party/pthreads-win32/sem_init.c

   1 /*
   2  * -------------------------------------------------------------
   3  *
   4  * Module: sem_init.c
   5  *
   6  * Purpose:
   7  *      Semaphores aren't actually part of PThreads.
   8  *      They are defined by the POSIX Standard:
   9  *
  10  *              POSIX 1003.1-2001
  11  *
  12  * -------------------------------------------------------------
  13  *
  14  *      Pthreads-win32 - POSIX Threads Library for Win32
  15  *      Copyright(C) 1998 John E. Bossom
  16  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  17  *
  18  *      Contact Email: rpj@callisto.canberra.edu.au
  19  *
  20  *      The current list of contributors is contained
  21  *      in the file CONTRIBUTORS included with the source
  22  *      code distribution. The list can also be seen at the
  23  *      following World Wide Web location:
  24  *      http://sources.redhat.com/pthreads-win32/contributors.html
  25  *
  26  *      This library is free software; you can redistribute it and/or
  27  *      modify it under the terms of the GNU Lesser General Public
  28  *      License as published by the Free Software Foundation; either
  29  *      version 2 of the License, or (at your option) any later version.
  30  *
  31  *      This library is distributed in the hope that it will be useful,
  32  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  33  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  34  *      Lesser General Public License for more details.
  35  *
  36  *      You should have received a copy of the GNU Lesser General Public
  37  *      License along with this library in the file COPYING.LIB;
  38  *      if not, write to the Free Software Foundation, Inc.,
  39  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  40  */
  41
  42 #include "pthread.h"
  43 #include "semaphore.h"
  44 #include "implement.h"
  45
  46 int
  47 sem_init (sem_t * sem, int pshared, unsigned int value)
  48      /*
  49       * ------------------------------------------------------
  50       * DOCPUBLIC
  51       *      This function initializes a semaphore. The
  52       *      initial value of the semaphore is 'value'
  53       *
  54       * PARAMETERS
  55       *      sem
  56       *              pointer to an instance of sem_t
  57       *
  58       *      pshared
  59       *              if zero, this semaphore may only be shared between
  60       *              threads in the same process.
  61       *              if nonzero, the semaphore can be shared between
  62       *              processes
  63       *
  64       *      value
  65       *              initial value of the semaphore counter
  66       *
  67       * DESCRIPTION
  68       *      This function initializes a semaphore. The
  69       *      initial value of the semaphore is set to 'value'.
  70       *
  71       * RESULTS
  72       *              0               successfully created semaphore,
  73       *              -1              failed, error in errno
  74       * ERRNO
  75       *              EINVAL          'sem' is not a valid semaphore, or
  76       *                              'value' >= SEM_VALUE_MAX
  77       *              ENOMEM          out of memory,
  78       *              ENOSPC          a required resource has been exhausted,
  79       *              ENOSYS          semaphores are not supported,
  80       *              EPERM           the process lacks appropriate privilege
  81       *
  82       * ------------------------------------------------------
  83       */
  84 {
  85   int result = 0;
  86   sem_t s = NULL;
  87
  88   if (pshared != 0)
  89     {
  90       /*
  91        * Creating a semaphore that can be shared between
  92        * processes
  93        */
  94       result = EPERM;
  95     }
  96   else if (value > (unsigned int)SEM_VALUE_MAX)
  97     {
  98       result = EINVAL;
  99     }
 100   else
 101     {
 102       s = (sem_t) calloc (1, sizeof (*s));
 103
 104       if (NULL == s)
 105         {
 106           result = ENOMEM;
 107         }
 108       else
 109         {
 110
 111           s->value = value;
 112           if (pthread_mutex_init(&s->lock, NULL) == 0)
 113             {
 114
 115 #if defined(NEED_SEM)
 116
 117           s->sem = CreateEvent (NULL,
 118                                 PTW32_FALSE,    /* auto (not manual) reset */
 119                                 PTW32_FALSE,    /* initial state is unset */
 120                                 NULL);
 121
 122           if (0 == s->sem)
 123             {
 124               free (s);
 125               (void) pthread_mutex_destroy(&s->lock);
 126               result = ENOSPC;
 127             }
 128           else
 129             {
 130               s->leftToUnblock = 0;
 131             }
 132
 133 #else /* NEED_SEM */
 134
 135               if ((s->sem = CreateSemaphore (NULL,      /* Always NULL */
 136                                              (long) 0,  /* Force threads to wait */
 137                                              (long) SEM_VALUE_MAX,      /* Maximum value */
 138                                              NULL)) == 0)       /* Name */
 139                 {
 140                   (void) pthread_mutex_destroy(&s->lock);
 141                   result = ENOSPC;
 142                 }
 143
 144 #endif /* NEED_SEM */
 145
 146             }
 147           else
 148             {
 149               result = ENOSPC;
 150             }
 151
 152           if (result != 0)
 153             {
 154               free(s);
 155             }
 156         }
 157     }
 158
 159   if (result != 0)
 160     {
 161       errno = result;
 162       return -1;
 163     }
 164
 165   *sem = s;
 166
 167   return 0;
 168
 169 }                               /* sem_init */