1/*
2 * ptw32_mutex_check_need_init.c
3 *
4 * Description:
5 * This translation unit implements mutual exclusion (mutex) primitives.
6 *
7 * --------------------------------------------------------------------------
8 *
9 *      Pthreads-win32 - POSIX Threads Library for Win32
10 *      Copyright(C) 1998 John E. Bossom
11 *      Copyright(C) 1999,2005 Pthreads-win32 contributors
12 *
13 *      Contact Email: rpj@callisto.canberra.edu.au
14 *
15 *      The current list of contributors is contained
16 *      in the file CONTRIBUTORS included with the source
17 *      code distribution. The list can also be seen at the
18 *      following World Wide Web location:
19 *      http://sources.redhat.com/pthreads-win32/contributors.html
20 *
21 *      This library is free software; you can redistribute it and/or
22 *      modify it under the terms of the GNU Lesser General Public
23 *      License as published by the Free Software Foundation; either
24 *      version 2 of the License, or (at your option) any later version.
25 *
26 *      This library is distributed in the hope that it will be useful,
27 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
28 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
29 *      Lesser General Public License for more details.
30 *
31 *      You should have received a copy of the GNU Lesser General Public
32 *      License along with this library in the file COPYING.LIB;
33 *      if not, write to the Free Software Foundation, Inc.,
34 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
35 */
36
37#include "pthread.h"
38#include "implement.h"
39
40static struct pthread_mutexattr_t_ ptw32_recursive_mutexattr_s =
41  {PTHREAD_PROCESS_PRIVATE, PTHREAD_MUTEX_RECURSIVE};
42static struct pthread_mutexattr_t_ ptw32_errorcheck_mutexattr_s =
43  {PTHREAD_PROCESS_PRIVATE, PTHREAD_MUTEX_ERRORCHECK};
44static pthread_mutexattr_t ptw32_recursive_mutexattr = &ptw32_recursive_mutexattr_s;
45static pthread_mutexattr_t ptw32_errorcheck_mutexattr = &ptw32_errorcheck_mutexattr_s;
46
47
48INLINE int
49ptw32_mutex_check_need_init (pthread_mutex_t * mutex)
50{
51  register int result = 0;
52  register pthread_mutex_t mtx;
53  ptw32_mcs_local_node_t node;
54
55  ptw32_mcs_lock_acquire(&ptw32_mutex_test_init_lock, &node);
56
57  /*
58   * We got here possibly under race
59   * conditions. Check again inside the critical section
60   * and only initialise if the mutex is valid (not been destroyed).
61   * If a static mutex has been destroyed, the application can
62   * re-initialise it only by calling pthread_mutex_init()
63   * explicitly.
64   */
65  mtx = *mutex;
66
67  if (mtx == PTHREAD_MUTEX_INITIALIZER)
68    {
69      result = pthread_mutex_init (mutex, NULL);
70    }
71  else if (mtx == PTHREAD_RECURSIVE_MUTEX_INITIALIZER)
72    {
73      result = pthread_mutex_init (mutex, &ptw32_recursive_mutexattr);
74    }
75  else if (mtx == PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
76    {
77      result = pthread_mutex_init (mutex, &ptw32_errorcheck_mutexattr);
78    }
79  else if (mtx == NULL)
80    {
81      /*
82       * The mutex has been destroyed while we were waiting to
83       * initialise it, so the operation that caused the
84       * auto-initialisation should fail.
85       */
86      result = EINVAL;
87    }
88
89  ptw32_mcs_lock_release(&node);
90
91  return (result);
92}
93