1*062c5bc4SJason Schmidlapp /*
2*062c5bc4SJason Schmidlapp * -------------------------------------------------------------
3*062c5bc4SJason Schmidlapp *
4*062c5bc4SJason Schmidlapp * Module: sem_destroy.c
5*062c5bc4SJason Schmidlapp *
6*062c5bc4SJason Schmidlapp * Purpose:
7*062c5bc4SJason Schmidlapp * Semaphores aren't actually part of the PThreads standard.
8*062c5bc4SJason Schmidlapp * They are defined by the POSIX Standard:
9*062c5bc4SJason Schmidlapp *
10*062c5bc4SJason Schmidlapp * POSIX 1003.1b-1993 (POSIX.1b)
11*062c5bc4SJason Schmidlapp *
12*062c5bc4SJason Schmidlapp * -------------------------------------------------------------
13*062c5bc4SJason Schmidlapp *
14*062c5bc4SJason Schmidlapp * --------------------------------------------------------------------------
15*062c5bc4SJason Schmidlapp *
16*062c5bc4SJason Schmidlapp * Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
17*062c5bc4SJason Schmidlapp * Copyright(C) 2008 Jason Schmidlapp
18*062c5bc4SJason Schmidlapp *
19*062c5bc4SJason Schmidlapp * Contact Email: jschmidlapp@users.sourceforge.net
20*062c5bc4SJason Schmidlapp *
21*062c5bc4SJason Schmidlapp *
22*062c5bc4SJason Schmidlapp * Based upon Pthreads-win32 - POSIX Threads Library for Win32
23*062c5bc4SJason Schmidlapp * Copyright(C) 1998 John E. Bossom
24*062c5bc4SJason Schmidlapp * Copyright(C) 1999,2005 Pthreads-win32 contributors
25*062c5bc4SJason Schmidlapp *
26*062c5bc4SJason Schmidlapp * Contact Email: rpj@callisto.canberra.edu.au
27*062c5bc4SJason Schmidlapp *
28*062c5bc4SJason Schmidlapp * The original list of contributors to the Pthreads-win32 project
29*062c5bc4SJason Schmidlapp * is contained in the file CONTRIBUTORS.ptw32 included with the
30*062c5bc4SJason Schmidlapp * source code distribution. The list can also be seen at the
31*062c5bc4SJason Schmidlapp * following World Wide Web location:
32*062c5bc4SJason Schmidlapp * http://sources.redhat.com/pthreads-win32/contributors.html
33*062c5bc4SJason Schmidlapp *
34*062c5bc4SJason Schmidlapp * This library is free software; you can redistribute it and/or
35*062c5bc4SJason Schmidlapp * modify it under the terms of the GNU Lesser General Public
36*062c5bc4SJason Schmidlapp * License as published by the Free Software Foundation; either
37*062c5bc4SJason Schmidlapp * version 2 of the License, or (at your option) any later version.
38*062c5bc4SJason Schmidlapp *
39*062c5bc4SJason Schmidlapp * This library is distributed in the hope that it will be useful,
40*062c5bc4SJason Schmidlapp * but WITHOUT ANY WARRANTY; without even the implied warranty of
41*062c5bc4SJason Schmidlapp * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
42*062c5bc4SJason Schmidlapp * Lesser General Public License for more details.
43*062c5bc4SJason Schmidlapp *
44*062c5bc4SJason Schmidlapp * You should have received a copy of the GNU Lesser General Public
45*062c5bc4SJason Schmidlapp * License along with this library in the file COPYING.LIB;
46*062c5bc4SJason Schmidlapp * if not, write to the Free Software Foundation, Inc.,
47*062c5bc4SJason Schmidlapp * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
48*062c5bc4SJason Schmidlapp */
49*062c5bc4SJason Schmidlapp
50*062c5bc4SJason Schmidlapp #include <stdio.h>
51*062c5bc4SJason Schmidlapp #include <stdlib.h>
52*062c5bc4SJason Schmidlapp
53*062c5bc4SJason Schmidlapp #include "pte_osal.h"
54*062c5bc4SJason Schmidlapp
55*062c5bc4SJason Schmidlapp #include "pthread.h"
56*062c5bc4SJason Schmidlapp #include "semaphore.h"
57*062c5bc4SJason Schmidlapp #include "implement.h"
58*062c5bc4SJason Schmidlapp
59*062c5bc4SJason Schmidlapp
60*062c5bc4SJason Schmidlapp int
sem_destroy(sem_t * sem)61*062c5bc4SJason Schmidlapp sem_destroy (sem_t * sem)
62*062c5bc4SJason Schmidlapp /*
63*062c5bc4SJason Schmidlapp * ------------------------------------------------------
64*062c5bc4SJason Schmidlapp * DOCPUBLIC
65*062c5bc4SJason Schmidlapp * This function destroys an unnamed semaphore.
66*062c5bc4SJason Schmidlapp *
67*062c5bc4SJason Schmidlapp * PARAMETERS
68*062c5bc4SJason Schmidlapp * sem
69*062c5bc4SJason Schmidlapp * pointer to an instance of sem_t
70*062c5bc4SJason Schmidlapp *
71*062c5bc4SJason Schmidlapp * DESCRIPTION
72*062c5bc4SJason Schmidlapp * This function destroys an unnamed semaphore.
73*062c5bc4SJason Schmidlapp *
74*062c5bc4SJason Schmidlapp * RESULTS
75*062c5bc4SJason Schmidlapp * 0 successfully destroyed semaphore,
76*062c5bc4SJason Schmidlapp * -1 failed, error in errno
77*062c5bc4SJason Schmidlapp * ERRNO
78*062c5bc4SJason Schmidlapp * EINVAL 'sem' is not a valid semaphore,
79*062c5bc4SJason Schmidlapp * ENOSYS semaphores are not supported,
80*062c5bc4SJason Schmidlapp * EBUSY threads (or processes) are currently
81*062c5bc4SJason Schmidlapp * blocked on 'sem'
82*062c5bc4SJason Schmidlapp *
83*062c5bc4SJason Schmidlapp * ------------------------------------------------------
84*062c5bc4SJason Schmidlapp */
85*062c5bc4SJason Schmidlapp {
86*062c5bc4SJason Schmidlapp int result = 0;
87*062c5bc4SJason Schmidlapp sem_t s = NULL;
88*062c5bc4SJason Schmidlapp
89*062c5bc4SJason Schmidlapp if (sem == NULL || *sem == NULL)
90*062c5bc4SJason Schmidlapp {
91*062c5bc4SJason Schmidlapp result = EINVAL;
92*062c5bc4SJason Schmidlapp }
93*062c5bc4SJason Schmidlapp else
94*062c5bc4SJason Schmidlapp {
95*062c5bc4SJason Schmidlapp s = *sem;
96*062c5bc4SJason Schmidlapp
97*062c5bc4SJason Schmidlapp if ((result = pthread_mutex_lock (&s->lock)) == 0)
98*062c5bc4SJason Schmidlapp {
99*062c5bc4SJason Schmidlapp if (s->value < 0)
100*062c5bc4SJason Schmidlapp {
101*062c5bc4SJason Schmidlapp (void) pthread_mutex_unlock (&s->lock);
102*062c5bc4SJason Schmidlapp result = EBUSY;
103*062c5bc4SJason Schmidlapp }
104*062c5bc4SJason Schmidlapp else
105*062c5bc4SJason Schmidlapp {
106*062c5bc4SJason Schmidlapp /* There are no threads currently blocked on this semaphore. */
107*062c5bc4SJason Schmidlapp pte_osResult osResult = pte_osSemaphoreDelete(s->sem);
108*062c5bc4SJason Schmidlapp
109*062c5bc4SJason Schmidlapp if (osResult != PTE_OS_OK)
110*062c5bc4SJason Schmidlapp {
111*062c5bc4SJason Schmidlapp (void) pthread_mutex_unlock (&s->lock);
112*062c5bc4SJason Schmidlapp result = EINVAL;
113*062c5bc4SJason Schmidlapp }
114*062c5bc4SJason Schmidlapp else
115*062c5bc4SJason Schmidlapp {
116*062c5bc4SJason Schmidlapp /*
117*062c5bc4SJason Schmidlapp * Invalidate the semaphore handle when we have the lock.
118*062c5bc4SJason Schmidlapp * Other sema operations should test this after acquiring the lock
119*062c5bc4SJason Schmidlapp * to check that the sema is still valid, i.e. before performing any
120*062c5bc4SJason Schmidlapp * operations. This may only be necessary before the sema op routine
121*062c5bc4SJason Schmidlapp * returns so that the routine can return EINVAL - e.g. if setting
122*062c5bc4SJason Schmidlapp * s->value to SEM_VALUE_MAX below does force a fall-through.
123*062c5bc4SJason Schmidlapp */
124*062c5bc4SJason Schmidlapp *sem = NULL;
125*062c5bc4SJason Schmidlapp
126*062c5bc4SJason Schmidlapp /* Prevent anyone else actually waiting on or posting this sema.
127*062c5bc4SJason Schmidlapp */
128*062c5bc4SJason Schmidlapp s->value = SEM_VALUE_MAX;
129*062c5bc4SJason Schmidlapp
130*062c5bc4SJason Schmidlapp (void) pthread_mutex_unlock (&s->lock);
131*062c5bc4SJason Schmidlapp
132*062c5bc4SJason Schmidlapp do
133*062c5bc4SJason Schmidlapp {
134*062c5bc4SJason Schmidlapp /* Give other threads a chance to run and exit any sema op
135*062c5bc4SJason Schmidlapp * routines. Due to the SEM_VALUE_MAX value, if sem_post or
136*062c5bc4SJason Schmidlapp * sem_wait were blocked by us they should fall through.
137*062c5bc4SJason Schmidlapp */
138*062c5bc4SJason Schmidlapp pte_osThreadSleep(1);
139*062c5bc4SJason Schmidlapp }
140*062c5bc4SJason Schmidlapp while (pthread_mutex_destroy (&s->lock) == EBUSY);
141*062c5bc4SJason Schmidlapp }
142*062c5bc4SJason Schmidlapp }
143*062c5bc4SJason Schmidlapp }
144*062c5bc4SJason Schmidlapp }
145*062c5bc4SJason Schmidlapp
146*062c5bc4SJason Schmidlapp if (result != 0)
147*062c5bc4SJason Schmidlapp {
148*062c5bc4SJason Schmidlapp errno = result;
149*062c5bc4SJason Schmidlapp return -1;
150*062c5bc4SJason Schmidlapp }
151*062c5bc4SJason Schmidlapp
152*062c5bc4SJason Schmidlapp free (s);
153*062c5bc4SJason Schmidlapp
154*062c5bc4SJason Schmidlapp return 0;
155*062c5bc4SJason Schmidlapp
156*062c5bc4SJason Schmidlapp } /* sem_destroy */
157