xref: /dragonfly/lib/libc/rpc/rpc_dtablesize.c (revision f2c43266)
1 /*-
2  * Copyright (c) 2009, Sun Microsystems, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  * - Redistributions of source code must retain the above copyright notice,
8  *   this list of conditions and the following disclaimer.
9  * - Redistributions in binary form must reproduce the above copyright notice,
10  *   this list of conditions and the following disclaimer in the documentation
11  *   and/or other materials provided with the distribution.
12  * - Neither the name of Sun Microsystems, Inc. nor the names of its
13  *   contributors may be used to endorse or promote products derived
14  *   from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  * POSSIBILITY OF SUCH DAMAGE.
27  *
28  * @(#)rpc_dtablesize.c 1.2 87/08/11 Copyr 1987 Sun Micro
29  * @(#)rpc_dtablesize.c	2.1 88/07/29 4.0 RPCSRC
30  * $NetBSD: rpc_dtablesize.c,v 1.14 1998/11/15 17:32:43 christos Exp $
31  * $FreeBSD: src/lib/libc/rpc/rpc_dtablesize.c,v 1.15 2004/10/16 06:11:35 obrien Exp $
32  * $DragonFly: src/lib/libc/rpc/rpc_dtablesize.c,v 1.3 2005/01/31 22:29:38 dillon Exp $
33  */
34 
35 #include "namespace.h"
36 #include <unistd.h>
37 #include "un-namespace.h"
38 
39 int _rpc_dtablesize(void);	/* XXX */
40 
41 /*
42  * Cache the result of getdtablesize(), so we don't have to do an
43  * expensive system call every time.
44  */
45 /*
46  * XXX In FreeBSD 2.x, you can have the maximum number of open file
47  * descriptors be greater than FD_SETSIZE (which us 256 by default).
48  *
49  * Since old programs tend to use this call to determine the first arg
50  * for _select(), having this return > FD_SETSIZE is a Bad Idea(TM)!
51  */
52 int
53 _rpc_dtablesize(void)
54 {
55 	static int size;
56 
57 	if (size == 0) {
58 		size = getdtablesize();
59 		if (size > FD_SETSIZE)
60 			size = FD_SETSIZE;
61 	}
62 	return (size);
63 }
64