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/*
* 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 "handle.h"
#include "thread.h"
#include "request.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 mutex_dump( 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 mutex_destroy( struct object *obj );
static const struct object_ops mutex_ops =
{
sizeof(struct mutex), /* size */
mutex_dump, /* dump */
add_queue, /* add_queue */
remove_queue, /* remove_queue */
mutex_signaled, /* signaled */
mutex_satisfied, /* satisfied */
NULL, /* get_poll_events */
NULL, /* poll_event */
no_read_fd, /* get_read_fd */
no_write_fd, /* get_write_fd */
no_flush, /* flush */
no_get_file_info, /* get_file_info */
mutex_destroy /* destroy */
};
static struct mutex *create_mutex( const WCHAR *name, size_t len, int owned )
{
struct mutex *mutex;
if ((mutex = create_named_object( &mutex_ops, name, len )))
{
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;
}
/* release a mutex once the recursion count is 0 */
static void do_release( struct mutex *mutex )
{
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 mutex->owner->mutex = mutex->next;
mutex->owner = NULL;
mutex->next = mutex->prev = NULL;
wake_up( &mutex->obj, 0 );
}
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 );
}
}
static void mutex_dump( struct object *obj, int verbose )
{
struct mutex *mutex = (struct mutex *)obj;
assert( obj->ops == &mutex_ops );
fprintf( stderr, "Mutex count=%u owner=%p ", mutex->count, mutex->owner );
dump_object_name( &mutex->obj );
fputc( '\n', stderr );
}
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 mutex_destroy( struct object *obj )
{
struct mutex *mutex = (struct mutex *)obj;
assert( obj->ops == &mutex_ops );
if (!mutex->count) return;
mutex->count = 0;
do_release( mutex );
}
/* create a mutex */
DECL_HANDLER(create_mutex)
{
size_t len = get_req_strlenW( req->name );
struct mutex *mutex;
req->handle = -1;
if ((mutex = create_mutex( req->name, len, req->owned )))
{
req->handle = alloc_handle( current->process, mutex, MUTEX_ALL_ACCESS, req->inherit );
release_object( mutex );
}
}
/* open a handle to a mutex */
DECL_HANDLER(open_mutex)
{
size_t len = get_req_strlenW( req->name );
req->handle = open_object( req->name, len, &mutex_ops, req->access, req->inherit );
}
/* release a mutex */
DECL_HANDLER(release_mutex)
{
struct mutex *mutex;
if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
MUTEX_MODIFY_STATE, &mutex_ops )))
{
if (!mutex->count || (mutex->owner != current)) set_error( ERROR_NOT_OWNER );
else if (!--mutex->count) do_release( mutex );
release_object( mutex );
}
}
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