2 * Server-side semaphore management
4 * Copyright (C) 1998 Alexandre Julliard
20 struct object obj; /* object header */
21 unsigned int count; /* current count */
22 unsigned int max; /* maximum possible count */
25 static void semaphore_dump( struct object *obj, int verbose );
26 static int semaphore_signaled( struct object *obj, struct thread *thread );
27 static int semaphore_satisfied( struct object *obj, struct thread *thread );
29 static const struct object_ops semaphore_ops =
31 sizeof(struct semaphore), /* size */
32 semaphore_dump, /* dump */
33 add_queue, /* add_queue */
34 remove_queue, /* remove_queue */
35 semaphore_signaled, /* signaled */
36 semaphore_satisfied, /* satisfied */
37 NULL, /* get_poll_events */
38 NULL, /* poll_event */
39 no_read_fd, /* get_read_fd */
40 no_write_fd, /* get_write_fd */
42 no_get_file_info, /* get_file_info */
43 no_destroy /* destroy */
47 static struct semaphore *create_semaphore( const WCHAR *name, size_t len,
48 unsigned int initial, unsigned int max )
50 struct semaphore *sem;
52 if (!max || (initial > max))
54 set_error( ERROR_INVALID_PARAMETER );
57 if ((sem = create_named_object( &semaphore_ops, name, len )))
59 if (get_error() != ERROR_ALREADY_EXISTS)
61 /* initialize it if it didn't already exist */
69 static unsigned int release_semaphore( int handle, unsigned int count )
71 struct semaphore *sem;
72 unsigned int prev = 0;
74 if ((sem = (struct semaphore *)get_handle_obj( current->process, handle,
75 SEMAPHORE_MODIFY_STATE, &semaphore_ops )))
78 if (sem->count + count < sem->count || sem->count + count > sem->max)
80 set_error( ERROR_TOO_MANY_POSTS );
84 /* there cannot be any thread waiting if the count is != 0 */
85 assert( !sem->obj.head );
91 wake_up( &sem->obj, count );
93 release_object( sem );
98 static void semaphore_dump( struct object *obj, int verbose )
100 struct semaphore *sem = (struct semaphore *)obj;
101 assert( obj->ops == &semaphore_ops );
102 fprintf( stderr, "Semaphore count=%d max=%d ", sem->count, sem->max );
103 dump_object_name( &sem->obj );
104 fputc( '\n', stderr );
107 static int semaphore_signaled( struct object *obj, struct thread *thread )
109 struct semaphore *sem = (struct semaphore *)obj;
110 assert( obj->ops == &semaphore_ops );
111 return (sem->count > 0);
114 static int semaphore_satisfied( struct object *obj, struct thread *thread )
116 struct semaphore *sem = (struct semaphore *)obj;
117 assert( obj->ops == &semaphore_ops );
118 assert( sem->count );
120 return 0; /* not abandoned */
123 /* create a semaphore */
124 DECL_HANDLER(create_semaphore)
126 size_t len = get_req_strlenW( req->name );
127 struct semaphore *sem;
130 if ((sem = create_semaphore( req->name, len, req->initial, req->max )))
132 req->handle = alloc_handle( current->process, sem, SEMAPHORE_ALL_ACCESS, req->inherit );
133 release_object( sem );
137 /* open a handle to a semaphore */
138 DECL_HANDLER(open_semaphore)
140 size_t len = get_req_strlenW( req->name );
141 req->handle = open_object( req->name, len, &semaphore_ops, req->access, req->inherit );
144 /* release a semaphore */
145 DECL_HANDLER(release_semaphore)
147 req->prev_count = release_semaphore( req->handle, req->count );