148 lines
4.2 KiB
C
148 lines
4.2 KiB
C
/*
|
|
* Server-side semaphore management
|
|
*
|
|
* Copyright (C) 1998 Alexandre Julliard
|
|
*/
|
|
|
|
#include <assert.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "winnt.h"
|
|
|
|
#include "handle.h"
|
|
#include "thread.h"
|
|
#include "request.h"
|
|
|
|
struct semaphore
|
|
{
|
|
struct object obj; /* object header */
|
|
unsigned int count; /* current count */
|
|
unsigned int max; /* maximum possible count */
|
|
};
|
|
|
|
static void semaphore_dump( struct object *obj, int verbose );
|
|
static int semaphore_signaled( struct object *obj, struct thread *thread );
|
|
static int semaphore_satisfied( struct object *obj, struct thread *thread );
|
|
|
|
static const struct object_ops semaphore_ops =
|
|
{
|
|
sizeof(struct semaphore), /* size */
|
|
semaphore_dump, /* dump */
|
|
add_queue, /* add_queue */
|
|
remove_queue, /* remove_queue */
|
|
semaphore_signaled, /* signaled */
|
|
semaphore_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 */
|
|
no_destroy /* destroy */
|
|
};
|
|
|
|
|
|
static struct semaphore *create_semaphore( const WCHAR *name, size_t len,
|
|
unsigned int initial, unsigned int max )
|
|
{
|
|
struct semaphore *sem;
|
|
|
|
if (!max || (initial > max))
|
|
{
|
|
set_error( STATUS_INVALID_PARAMETER );
|
|
return NULL;
|
|
}
|
|
if ((sem = create_named_object( &semaphore_ops, name, len )))
|
|
{
|
|
if (get_error() != STATUS_OBJECT_NAME_COLLISION)
|
|
{
|
|
/* initialize it if it didn't already exist */
|
|
sem->count = initial;
|
|
sem->max = max;
|
|
}
|
|
}
|
|
return sem;
|
|
}
|
|
|
|
static unsigned int release_semaphore( int handle, unsigned int count )
|
|
{
|
|
struct semaphore *sem;
|
|
unsigned int prev = 0;
|
|
|
|
if ((sem = (struct semaphore *)get_handle_obj( current->process, handle,
|
|
SEMAPHORE_MODIFY_STATE, &semaphore_ops )))
|
|
{
|
|
prev = sem->count;
|
|
if (sem->count + count < sem->count || sem->count + count > sem->max)
|
|
{
|
|
set_error( STATUS_SEMAPHORE_LIMIT_EXCEEDED );
|
|
}
|
|
else if (sem->count)
|
|
{
|
|
/* there cannot be any thread waiting if the count is != 0 */
|
|
assert( !sem->obj.head );
|
|
sem->count += count;
|
|
}
|
|
else
|
|
{
|
|
sem->count = count;
|
|
wake_up( &sem->obj, count );
|
|
}
|
|
release_object( sem );
|
|
}
|
|
return prev;
|
|
}
|
|
|
|
static void semaphore_dump( struct object *obj, int verbose )
|
|
{
|
|
struct semaphore *sem = (struct semaphore *)obj;
|
|
assert( obj->ops == &semaphore_ops );
|
|
fprintf( stderr, "Semaphore count=%d max=%d ", sem->count, sem->max );
|
|
dump_object_name( &sem->obj );
|
|
fputc( '\n', stderr );
|
|
}
|
|
|
|
static int semaphore_signaled( struct object *obj, struct thread *thread )
|
|
{
|
|
struct semaphore *sem = (struct semaphore *)obj;
|
|
assert( obj->ops == &semaphore_ops );
|
|
return (sem->count > 0);
|
|
}
|
|
|
|
static int semaphore_satisfied( struct object *obj, struct thread *thread )
|
|
{
|
|
struct semaphore *sem = (struct semaphore *)obj;
|
|
assert( obj->ops == &semaphore_ops );
|
|
assert( sem->count );
|
|
sem->count--;
|
|
return 0; /* not abandoned */
|
|
}
|
|
|
|
/* create a semaphore */
|
|
DECL_HANDLER(create_semaphore)
|
|
{
|
|
struct semaphore *sem;
|
|
|
|
req->handle = -1;
|
|
if ((sem = create_semaphore( get_req_data(req), get_req_data_size(req),
|
|
req->initial, req->max )))
|
|
{
|
|
req->handle = alloc_handle( current->process, sem, SEMAPHORE_ALL_ACCESS, req->inherit );
|
|
release_object( sem );
|
|
}
|
|
}
|
|
|
|
/* open a handle to a semaphore */
|
|
DECL_HANDLER(open_semaphore)
|
|
{
|
|
req->handle = open_object( get_req_data(req), get_req_data_size(req),
|
|
&semaphore_ops, req->access, req->inherit );
|
|
}
|
|
|
|
/* release a semaphore */
|
|
DECL_HANDLER(release_semaphore)
|
|
{
|
|
req->prev_count = release_semaphore( req->handle, req->count );
|
|
}
|