2 * Server-side semaphore management
4 * Copyright (C) 1998 Alexandre Julliard
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
33 struct object obj
; /* object header */
34 unsigned int count
; /* current count */
35 unsigned int max
; /* maximum possible count */
38 static void semaphore_dump( struct object
*obj
, int verbose
);
39 static int semaphore_signaled( struct object
*obj
, struct thread
*thread
);
40 static int semaphore_satisfied( struct object
*obj
, struct thread
*thread
);
42 static const struct object_ops semaphore_ops
=
44 sizeof(struct semaphore
), /* size */
45 semaphore_dump
, /* dump */
46 add_queue
, /* add_queue */
47 remove_queue
, /* remove_queue */
48 semaphore_signaled
, /* signaled */
49 semaphore_satisfied
, /* satisfied */
50 NULL
, /* get_poll_events */
51 NULL
, /* poll_event */
52 no_get_fd
, /* get_fd */
54 no_get_file_info
, /* get_file_info */
55 NULL
, /* queue_async */
56 no_destroy
/* destroy */
60 static struct semaphore
*create_semaphore( const WCHAR
*name
, size_t len
,
61 unsigned int initial
, unsigned int max
)
63 struct semaphore
*sem
;
65 if (!max
|| (initial
> max
))
67 set_error( STATUS_INVALID_PARAMETER
);
70 if ((sem
= create_named_object( &semaphore_ops
, name
, len
)))
72 if (get_error() != STATUS_OBJECT_NAME_COLLISION
)
74 /* initialize it if it didn't already exist */
82 static unsigned int release_semaphore( handle_t handle
, unsigned int count
)
84 struct semaphore
*sem
;
85 unsigned int prev
= 0;
87 if ((sem
= (struct semaphore
*)get_handle_obj( current
->process
, handle
,
88 SEMAPHORE_MODIFY_STATE
, &semaphore_ops
)))
91 if (sem
->count
+ count
< sem
->count
|| sem
->count
+ count
> sem
->max
)
93 set_error( STATUS_SEMAPHORE_LIMIT_EXCEEDED
);
97 /* there cannot be any thread waiting if the count is != 0 */
98 assert( !sem
->obj
.head
);
104 wake_up( &sem
->obj
, count
);
106 release_object( sem
);
111 static void semaphore_dump( struct object
*obj
, int verbose
)
113 struct semaphore
*sem
= (struct semaphore
*)obj
;
114 assert( obj
->ops
== &semaphore_ops
);
115 fprintf( stderr
, "Semaphore count=%d max=%d ", sem
->count
, sem
->max
);
116 dump_object_name( &sem
->obj
);
117 fputc( '\n', stderr
);
120 static int semaphore_signaled( struct object
*obj
, struct thread
*thread
)
122 struct semaphore
*sem
= (struct semaphore
*)obj
;
123 assert( obj
->ops
== &semaphore_ops
);
124 return (sem
->count
> 0);
127 static int semaphore_satisfied( struct object
*obj
, struct thread
*thread
)
129 struct semaphore
*sem
= (struct semaphore
*)obj
;
130 assert( obj
->ops
== &semaphore_ops
);
131 assert( sem
->count
);
133 return 0; /* not abandoned */
136 /* create a semaphore */
137 DECL_HANDLER(create_semaphore
)
139 struct semaphore
*sem
;
142 if ((sem
= create_semaphore( get_req_data(), get_req_data_size(),
143 req
->initial
, req
->max
)))
145 reply
->handle
= alloc_handle( current
->process
, sem
, SEMAPHORE_ALL_ACCESS
, req
->inherit
);
146 release_object( sem
);
150 /* open a handle to a semaphore */
151 DECL_HANDLER(open_semaphore
)
153 reply
->handle
= open_object( get_req_data(), get_req_data_size(),
154 &semaphore_ops
, req
->access
, req
->inherit
);
157 /* release a semaphore */
158 DECL_HANDLER(release_semaphore
)
160 reply
->prev_count
= release_semaphore( req
->handle
, req
->count
);