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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/*
* pthread_mutex_trylock.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
*/
#include "pthread.h"
#include "implement.h"
int
pthread_mutex_trylock (pthread_mutex_t * mutex)
{
pthread_mutex_t mx;
int kind;
int result = 0;
/*
* Let the system deal with invalid pointers.
*/
/*
* 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;
kind = mx->kind;
if (kind >= 0)
{
/* Non-robust */
if (0 == (PTW32_INTERLOCKED_LONG) PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG (
(PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx,
(PTW32_INTERLOCKED_LONG) 1,
(PTW32_INTERLOCKED_LONG) 0))
{
if (kind != PTHREAD_MUTEX_NORMAL)
{
mx->recursive_count = 1;
mx->ownerThread = pthread_self ();
}
}
else
{
if (kind == PTHREAD_MUTEX_RECURSIVE &&
pthread_equal (mx->ownerThread, pthread_self ()))
{
mx->recursive_count++;
}
else
{
result = EBUSY;
}
}
}
else
{
/*
* Robust types
* All types record the current owner thread.
* The mutex is added to a per thread list when ownership is acquired.
*/
pthread_t self;
ptw32_robust_state_t* statePtr = &mx->robustNode->stateInconsistent;
if ((PTW32_INTERLOCKED_LONG)PTW32_ROBUST_NOTRECOVERABLE ==
PTW32_INTERLOCKED_EXCHANGE_ADD_LONG(
(PTW32_INTERLOCKED_LONGPTR)statePtr,
(PTW32_INTERLOCKED_LONG)0))
{
return ENOTRECOVERABLE;
}
self = pthread_self();
kind = -kind - 1; /* Convert to non-robust range */
if (0 == (PTW32_INTERLOCKED_LONG) PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG (
(PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx,
(PTW32_INTERLOCKED_LONG) 1,
(PTW32_INTERLOCKED_LONG) 0))
{
if (kind != PTHREAD_MUTEX_NORMAL)
{
mx->recursive_count = 1;
}
ptw32_robust_mutex_add(mutex, self);
}
else
{
if (PTHREAD_MUTEX_RECURSIVE == kind &&
pthread_equal (mx->ownerThread, pthread_self ()))
{
mx->recursive_count++;
}
else
{
if (EOWNERDEAD == (result = ptw32_robust_mutex_inherit(mutex)))
{
mx->recursive_count = 1;
ptw32_robust_mutex_add(mutex, self);
}
else
{
if (0 == result)
{
result = EBUSY;
}
}
}
}
}
return (result);
}
|
