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/*
* mutex.c
*
* Description:
* This translation unit implements mutual exclusion (mutex) primitives.
*/
#include "pthread.h"
#include "implement.h"
static int
insert_attr(pthread_mutexattr_t *attr)
{
/* Add this attribute object to a list. */
/* FIXME: implement using some dynamic scheme. */
return 0;
}
static int
is_attr(pthread_mutexattr_t *attr)
{
/* Return 0 if present, 1 otherwise. */
/* FIXME: implement. For now, pretend the attribute is always okay, unless
it is NULL. */
return (attr == NULL) ? 1 : 0;
}
static int
remove_attr(pthread_mutexattr_t *attr)
{
/* Remove this attribute object from the list. */
/* FIXME: implement. */
return 0;
}
int
pthread_mutex_init(pthread_mutex_t *mutex, pthread_mutex_attr_t *attr)
{
/* FIXME: Attributes are currently ignored. */
if ((is_attr(attr) != 0) || (mutex == NULL))
{
return EINVAL;
}
/* Create an unnamed mutex with default security and one which is
initially not held by the thread. Default security (arg1 = NULL)
is portable to Win9x and NT, as Win9x has no security model. */
if ((*mutex = CreateMutex(NULL, FALSE, NULL)) == NULL)
{
/* This is almost certainly due to a lack of resources. */
return ENOMEM;
}
return 0;
}
int
pthread_mutex_destroy(pthread_mutex_t *mutex)
{
if ((mutex == NULL) || (CloseHandle(*mutex) != TRUE))
{
/* This is almost certainly due to an invalid handle. */
return EINVAL;
}
return 0;
}
int
pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
if (attr == NULL)
{
/* This is disallowed. */
return EINVAL;
}
attr->ptr = malloc(sizeof(_pthread_mutexattr_t));
if (attr->ptr == NULL)
{
return ENOMEM;
}
(_pthread_mutexattr_t *) (attr->ptr).proc_shared = PTHREAD_PROCESS_PRIVATE;
return 0;
}
int
pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
{
if (is_attr(attr) != 0)
{
return EINVAL;
}
free(attr->ptr);
return 0;
}
int
pthread_mutexattr_setpshared(pthread_mutexattr_t *attr, int process_shared)
{
/* Ensure the value for this attribute is within the legal range. */
if ((process_shared != PTHREAD_PROCESS_PRIVATE) ||
(process_shared != PTHREAD_PROCESS_SHARED))
{
return EINVAL;
}
/* Ensure attr points to a valid attribute object. */
if (is_attr(attr) != 0)
{
return EINVAL;
}
/* Everything is okay. */
(_pthread_mutexattr_t *) (attr->ptr)->proc_shared = process_shared;
return 0;
}
int
pthread_mutexattr_getpshared(const pthread_mutexattr_t *attr,
int *process_shared)
{
if (is_attr(attr) != 0)
{
return EINVAL;
}
/* Everything is okay. */
*process_shared = (_pthread_mutexattr_t *) (attr->ptr)->proc_shared;
return 0;
}
int
pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr,
int protocol)
{
/* This function is not supported. */
return ENOSYS;
}
int
pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr,
int *protocol)
{
/* This function is not supported. */
return ENOSYS;
}
int
pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr,
int ceiling)
{
/* This function is not supported. */
return ENOSYS;
}
int
pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *attr,
int *ceiling)
{
/* This function is not supported. */
return ENOSYS;
}
int
pthread_mutex_lock(pthread_mutex_t *mutex)
{
switch (WaitForSingleObject(*mutex, INFINITE))
{
case WAIT_ABANDONED_0:
/* Thread holding the mutex abandoned it. Fall through. */
case WAIT_FAILED:
/* This is probably due to an invalid handle. */
return EINVAL;
case WAIT_OBJECT_0:
/* We're good. */
return 0;
}
/* Not reached. */
}
int
pthread_mutex_unlock(pthread_mutex_t *mutex)
{
if (ReleaseMutex(*mutex) != TRUE)
{
/* This is probably due to an invalid handle. */
return EINVAL;
}
else
{
return 0;
}
/* Not reached. */
}
int
pthread_mutex_trylock(pthread_mutex_t *mutex)
{
/* If the mutex is already held, return EBUSY. */
switch (WaitForSingleObject(*mutex, 0))
{
case WAIT_ABANDONED_0:
/* Thread holding the mutex abandoned it. Fall through. */
case WAIT_FAILED:
/* This is probably due to an invalid handle. */
return EINVAL;
case WAIT_TIMEOUT:
/* We couldn't get the lock. */
return EBUSY;
case WAIT_OBJECT_0:
/* We're good. */
return 0;
}
/* Not reached. */
}
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