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
46int
47sem_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 */
170