1*062c5bc4SJason Schmidlapp /*
2*062c5bc4SJason Schmidlapp * pthread_mutex_lock.c
3*062c5bc4SJason Schmidlapp *
4*062c5bc4SJason Schmidlapp * Description:
5*062c5bc4SJason Schmidlapp * This translation unit implements mutual exclusion (mutex) primitives.
6*062c5bc4SJason Schmidlapp *
7*062c5bc4SJason Schmidlapp * --------------------------------------------------------------------------
8*062c5bc4SJason Schmidlapp *
9*062c5bc4SJason Schmidlapp * Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
10*062c5bc4SJason Schmidlapp * Copyright(C) 2008 Jason Schmidlapp
11*062c5bc4SJason Schmidlapp *
12*062c5bc4SJason Schmidlapp * Contact Email: jschmidlapp@users.sourceforge.net
13*062c5bc4SJason Schmidlapp *
14*062c5bc4SJason Schmidlapp *
15*062c5bc4SJason Schmidlapp * Based upon Pthreads-win32 - POSIX Threads Library for Win32
16*062c5bc4SJason Schmidlapp * Copyright(C) 1998 John E. Bossom
17*062c5bc4SJason Schmidlapp * Copyright(C) 1999,2005 Pthreads-win32 contributors
18*062c5bc4SJason Schmidlapp *
19*062c5bc4SJason Schmidlapp * Contact Email: rpj@callisto.canberra.edu.au
20*062c5bc4SJason Schmidlapp *
21*062c5bc4SJason Schmidlapp * The original list of contributors to the Pthreads-win32 project
22*062c5bc4SJason Schmidlapp * is contained in the file CONTRIBUTORS.ptw32 included with the
23*062c5bc4SJason Schmidlapp * source code distribution. The list can also be seen at the
24*062c5bc4SJason Schmidlapp * following World Wide Web location:
25*062c5bc4SJason Schmidlapp * http://sources.redhat.com/pthreads-win32/contributors.html
26*062c5bc4SJason Schmidlapp *
27*062c5bc4SJason Schmidlapp * This library is free software; you can redistribute it and/or
28*062c5bc4SJason Schmidlapp * modify it under the terms of the GNU Lesser General Public
29*062c5bc4SJason Schmidlapp * License as published by the Free Software Foundation; either
30*062c5bc4SJason Schmidlapp * version 2 of the License, or (at your option) any later version.
31*062c5bc4SJason Schmidlapp *
32*062c5bc4SJason Schmidlapp * This library is distributed in the hope that it will be useful,
33*062c5bc4SJason Schmidlapp * but WITHOUT ANY WARRANTY; without even the implied warranty of
34*062c5bc4SJason Schmidlapp * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
35*062c5bc4SJason Schmidlapp * Lesser General Public License for more details.
36*062c5bc4SJason Schmidlapp *
37*062c5bc4SJason Schmidlapp * You should have received a copy of the GNU Lesser General Public
38*062c5bc4SJason Schmidlapp * License along with this library in the file COPYING.LIB;
39*062c5bc4SJason Schmidlapp * if not, write to the Free Software Foundation, Inc.,
40*062c5bc4SJason Schmidlapp * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
41*062c5bc4SJason Schmidlapp */
42*062c5bc4SJason Schmidlapp
43*062c5bc4SJason Schmidlapp #include <stdio.h>
44*062c5bc4SJason Schmidlapp #include <stdlib.h>
45*062c5bc4SJason Schmidlapp
46*062c5bc4SJason Schmidlapp #include "pthread.h"
47*062c5bc4SJason Schmidlapp #include "implement.h"
48*062c5bc4SJason Schmidlapp
49*062c5bc4SJason Schmidlapp
50*062c5bc4SJason Schmidlapp int
pthread_mutex_lock(pthread_mutex_t * mutex)51*062c5bc4SJason Schmidlapp pthread_mutex_lock (pthread_mutex_t * mutex)
52*062c5bc4SJason Schmidlapp {
53*062c5bc4SJason Schmidlapp int result = 0;
54*062c5bc4SJason Schmidlapp pthread_mutex_t mx;
55*062c5bc4SJason Schmidlapp
56*062c5bc4SJason Schmidlapp /*
57*062c5bc4SJason Schmidlapp * Let the system deal with invalid pointers.
58*062c5bc4SJason Schmidlapp */
59*062c5bc4SJason Schmidlapp if (*mutex == NULL)
60*062c5bc4SJason Schmidlapp {
61*062c5bc4SJason Schmidlapp return EINVAL;
62*062c5bc4SJason Schmidlapp }
63*062c5bc4SJason Schmidlapp
64*062c5bc4SJason Schmidlapp /*
65*062c5bc4SJason Schmidlapp * We do a quick check to see if we need to do more work
66*062c5bc4SJason Schmidlapp * to initialise a static mutex. We check
67*062c5bc4SJason Schmidlapp * again inside the guarded section of pte_mutex_check_need_init()
68*062c5bc4SJason Schmidlapp * to avoid race conditions.
69*062c5bc4SJason Schmidlapp */
70*062c5bc4SJason Schmidlapp if (*mutex >= PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
71*062c5bc4SJason Schmidlapp {
72*062c5bc4SJason Schmidlapp if ((result = pte_mutex_check_need_init (mutex)) != 0)
73*062c5bc4SJason Schmidlapp {
74*062c5bc4SJason Schmidlapp return (result);
75*062c5bc4SJason Schmidlapp }
76*062c5bc4SJason Schmidlapp }
77*062c5bc4SJason Schmidlapp
78*062c5bc4SJason Schmidlapp mx = *mutex;
79*062c5bc4SJason Schmidlapp
80*062c5bc4SJason Schmidlapp if (mx->kind == PTHREAD_MUTEX_NORMAL)
81*062c5bc4SJason Schmidlapp {
82*062c5bc4SJason Schmidlapp if (PTE_ATOMIC_EXCHANGE(
83*062c5bc4SJason Schmidlapp &mx->lock_idx,
84*062c5bc4SJason Schmidlapp 1) != 0)
85*062c5bc4SJason Schmidlapp {
86*062c5bc4SJason Schmidlapp while (PTE_ATOMIC_EXCHANGE(&mx->lock_idx,-1) != 0)
87*062c5bc4SJason Schmidlapp {
88*062c5bc4SJason Schmidlapp if (pte_osSemaphorePend(mx->handle,NULL) != PTE_OS_OK)
89*062c5bc4SJason Schmidlapp {
90*062c5bc4SJason Schmidlapp result = EINVAL;
91*062c5bc4SJason Schmidlapp break;
92*062c5bc4SJason Schmidlapp }
93*062c5bc4SJason Schmidlapp }
94*062c5bc4SJason Schmidlapp }
95*062c5bc4SJason Schmidlapp }
96*062c5bc4SJason Schmidlapp else
97*062c5bc4SJason Schmidlapp {
98*062c5bc4SJason Schmidlapp pthread_t self = pthread_self();
99*062c5bc4SJason Schmidlapp
100*062c5bc4SJason Schmidlapp if (PTE_ATOMIC_COMPARE_EXCHANGE(&mx->lock_idx,1,0) == 0)
101*062c5bc4SJason Schmidlapp {
102*062c5bc4SJason Schmidlapp mx->recursive_count = 1;
103*062c5bc4SJason Schmidlapp mx->ownerThread = self;
104*062c5bc4SJason Schmidlapp }
105*062c5bc4SJason Schmidlapp else
106*062c5bc4SJason Schmidlapp {
107*062c5bc4SJason Schmidlapp if (pthread_equal (mx->ownerThread, self))
108*062c5bc4SJason Schmidlapp {
109*062c5bc4SJason Schmidlapp if (mx->kind == PTHREAD_MUTEX_RECURSIVE)
110*062c5bc4SJason Schmidlapp {
111*062c5bc4SJason Schmidlapp mx->recursive_count++;
112*062c5bc4SJason Schmidlapp }
113*062c5bc4SJason Schmidlapp else
114*062c5bc4SJason Schmidlapp {
115*062c5bc4SJason Schmidlapp result = EDEADLK;
116*062c5bc4SJason Schmidlapp }
117*062c5bc4SJason Schmidlapp }
118*062c5bc4SJason Schmidlapp else
119*062c5bc4SJason Schmidlapp {
120*062c5bc4SJason Schmidlapp while (PTE_ATOMIC_EXCHANGE(&mx->lock_idx,-1) != 0)
121*062c5bc4SJason Schmidlapp {
122*062c5bc4SJason Schmidlapp if (pte_osSemaphorePend(mx->handle,NULL) != PTE_OS_OK)
123*062c5bc4SJason Schmidlapp {
124*062c5bc4SJason Schmidlapp result = EINVAL;
125*062c5bc4SJason Schmidlapp break;
126*062c5bc4SJason Schmidlapp }
127*062c5bc4SJason Schmidlapp }
128*062c5bc4SJason Schmidlapp
129*062c5bc4SJason Schmidlapp if (0 == result)
130*062c5bc4SJason Schmidlapp {
131*062c5bc4SJason Schmidlapp mx->recursive_count = 1;
132*062c5bc4SJason Schmidlapp mx->ownerThread = self;
133*062c5bc4SJason Schmidlapp }
134*062c5bc4SJason Schmidlapp }
135*062c5bc4SJason Schmidlapp }
136*062c5bc4SJason Schmidlapp
137*062c5bc4SJason Schmidlapp }
138*062c5bc4SJason Schmidlapp
139*062c5bc4SJason Schmidlapp return (result);
140*062c5bc4SJason Schmidlapp }
141