Sweden-Number/server/mutex.c

143 lines
3.8 KiB
C

/*
* Server-side mutex management
*
* Copyright (C) 1998 Alexandre Julliard
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include "winerror.h"
#include "winnt.h"
#include "server/thread.h"
struct mutex
{
struct object obj; /* object header */
struct thread *owner; /* mutex owner */
unsigned int count; /* recursion count */
int abandoned; /* has it been abandoned? */
struct mutex *next;
struct mutex *prev;
};
static void dump_mutex( struct object *obj, int verbose );
static int mutex_signaled( struct object *obj, struct thread *thread );
static int mutex_satisfied( struct object *obj, struct thread *thread );
static void destroy_mutex( struct object *obj );
static const struct object_ops mutex_ops =
{
dump_mutex,
mutex_signaled,
mutex_satisfied,
destroy_mutex
};
struct object *create_mutex( const char *name, int owned )
{
struct mutex *mutex;
if (!(mutex = (struct mutex *)create_named_object( name, &mutex_ops, sizeof(*mutex) )))
return NULL;
if (GET_ERROR() != ERROR_ALREADY_EXISTS)
{
/* initialize it if it didn't already exist */
mutex->count = 0;
mutex->owner = NULL;
mutex->abandoned = 0;
mutex->next = mutex->prev = NULL;
if (owned) mutex_satisfied( &mutex->obj, current );
}
return &mutex->obj;
}
int open_mutex( unsigned int access, int inherit, const char *name )
{
return open_object( name, &mutex_ops, access, inherit );
}
/* release a mutex once the recursion count is 0 */
static void do_release( struct mutex *mutex, struct thread *thread )
{
assert( !mutex->count );
/* remove the mutex from the thread list of owned mutexes */
if (mutex->next) mutex->next->prev = mutex->prev;
if (mutex->prev) mutex->prev->next = mutex->next;
else thread->mutex = mutex->next;
mutex->owner = NULL;
mutex->next = mutex->prev = NULL;
wake_up( &mutex->obj, 0 );
}
int release_mutex( int handle )
{
struct mutex *mutex;
if (!(mutex = (struct mutex *)get_handle_obj( current->process, handle,
MUTEX_MODIFY_STATE, &mutex_ops )))
return 0;
if (!mutex->count || (mutex->owner != current))
{
SET_ERROR( ERROR_NOT_OWNER );
return 0;
}
if (!--mutex->count) do_release( mutex, current );
release_object( mutex );
return 1;
}
void abandon_mutexes( struct thread *thread )
{
while (thread->mutex)
{
struct mutex *mutex = thread->mutex;
assert( mutex->owner == thread );
mutex->count = 0;
mutex->abandoned = 1;
do_release( mutex, thread );
}
}
static void dump_mutex( struct object *obj, int verbose )
{
struct mutex *mutex = (struct mutex *)obj;
assert( obj->ops == &mutex_ops );
printf( "Mutex count=%u owner=%p\n", mutex->count, mutex->owner );
}
static int mutex_signaled( struct object *obj, struct thread *thread )
{
struct mutex *mutex = (struct mutex *)obj;
assert( obj->ops == &mutex_ops );
return (!mutex->count || (mutex->owner == thread));
}
static int mutex_satisfied( struct object *obj, struct thread *thread )
{
struct mutex *mutex = (struct mutex *)obj;
assert( obj->ops == &mutex_ops );
assert( !mutex->count || (mutex->owner == thread) );
if (!mutex->count++) /* FIXME: avoid wrap-around */
{
assert( !mutex->owner );
mutex->owner = thread;
mutex->prev = NULL;
if ((mutex->next = thread->mutex)) mutex->next->prev = mutex;
thread->mutex = mutex;
}
if (!mutex->abandoned) return 0;
mutex->abandoned = 0;
return 1;
}
static void destroy_mutex( struct object *obj )
{
struct mutex *mutex = (struct mutex *)obj;
assert( obj->ops == &mutex_ops );
free( mutex );
}