summaryrefslogtreecommitdiff
path: root/pthread_mutex_lock.c
blob: b819a7b92ebb2cc2ea146f52d5a9a6c7f4865848 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
/*
 * pthread_mutex_lock.c
 *
 * Description:
 * This translation unit implements mutual exclusion (mutex) primitives.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads-win32 - POSIX Threads Library for Win32
 *      Copyright(C) 1998 John E. Bossom
 *      Copyright(C) 1999,2005 Pthreads-win32 contributors
 * 
 *      Contact Email: rpj@callisto.canberra.edu.au
 * 
 *      The current list of contributors is contained
 *      in the file CONTRIBUTORS included with the source
 *      code distribution. The list can also be seen at the
 *      following World Wide Web location:
 *      http://sources.redhat.com/pthreads-win32/contributors.html
 * 
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation; either
 *      version 2 of the License, or (at your option) any later version.
 * 
 *      This 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
 *      Lesser General Public License for more details.
 * 
 *      You should have received a copy of the GNU Lesser General Public
 *      License along with this library in the file COPYING.LIB;
 *      if not, write to the Free Software Foundation, Inc.,
 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#ifndef _UWIN
/*#   include <process.h> */
#endif
#include "pthread.h"
#include "implement.h"

int
pthread_mutex_lock (pthread_mutex_t * mutex)
{
  int result = 0;
  pthread_mutex_t mx;

  /*
   * Let the system deal with invalid pointers.
   */
  if (*mutex == NULL)
    {
      return EINVAL;
    }

  /*
   * We do a quick check to see if we need to do more work
   * to initialise a static mutex. We check
   * again inside the guarded section of ptw32_mutex_check_need_init()
   * to avoid race conditions.
   */
  if (*mutex >= PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
    {
      if ((result = ptw32_mutex_check_need_init (mutex)) != 0)
	{
	  return (result);
	}
    }

  mx = *mutex;

  if (mx->kind == PTHREAD_MUTEX_NORMAL)
    {
      if ((LONG) PTW32_INTERLOCKED_EXCHANGE(
		   (LPLONG) &mx->lock_idx,
		   (LONG) 1) != 0)
	{
	  while ((LONG) PTW32_INTERLOCKED_EXCHANGE(
                          (LPLONG) &mx->lock_idx,
			  (LONG) -1) != 0)
	    {
	      if (WAIT_OBJECT_0 != WaitForSingleObject (mx->event, INFINITE))
	        {
	          result = EINVAL;
		  break;
	        }
	    }
	}
    }
  else
    {
      pthread_t self = pthread_self();

      if ((PTW32_INTERLOCKED_LONG) PTW32_INTERLOCKED_COMPARE_EXCHANGE(
                   (PTW32_INTERLOCKED_LPLONG) &mx->lock_idx,
		   (PTW32_INTERLOCKED_LONG) 1,
		   (PTW32_INTERLOCKED_LONG) 0) == 0)
	{
	  mx->recursive_count = 1;
	  mx->ownerThread = self;
	}
      else
	{
	  if (pthread_equal (mx->ownerThread, self))
	    {
	      if (mx->kind == PTHREAD_MUTEX_RECURSIVE)
		{
		  mx->recursive_count++;
		}
	      else
		{
		  result = EDEADLK;
		}
	    }
	  else
	    {
	      while ((LONG) PTW32_INTERLOCKED_EXCHANGE(
                              (LPLONG) &mx->lock_idx,
			      (LONG) -1) != 0)
		{
	          if (WAIT_OBJECT_0 != WaitForSingleObject (mx->event, INFINITE))
		    {
	              result = EINVAL;
		      break;
		    }
		}

	      if (0 == result)
		{
		  mx->recursive_count = 1;
		  mx->ownerThread = self;
		}
	    }
	}
    }

  return (result);
}