xref: /freebsd/lib/libc/rpc/rpc_dtablesize.c (revision 5ebc7e6281887681c3a348a5a4c902e262ccd656)
1 /*
2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
3  * unrestricted use provided that this legend is included on all tape
4  * media and as a part of the software program in whole or part.  Users
5  * may copy or modify Sun RPC without charge, but are not authorized
6  * to license or distribute it to anyone else except as part of a product or
7  * program developed by the user.
8  *
9  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
10  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
11  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
12  *
13  * Sun RPC is provided with no support and without any obligation on the
14  * part of Sun Microsystems, Inc. to assist in its use, correction,
15  * modification or enhancement.
16  *
17  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
18  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
19  * OR ANY PART THEREOF.
20  *
21  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
22  * or profits or other special, indirect and consequential damages, even if
23  * Sun has been advised of the possibility of such damages.
24  *
25  * Sun Microsystems, Inc.
26  * 2550 Garcia Avenue
27  * Mountain View, California  94043
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 /*static char *sccsid = "from: @(#)rpc_dtablesize.c 1.2 87/08/11 Copyr 1987 Sun Micro";*/
32 /*static char *sccsid = "from: @(#)rpc_dtablesize.c	2.1 88/07/29 4.0 RPCSRC";*/
33 static char *rcsid = "rpc_dtablesize.c,v 1.1 1994/08/07 18:36:02 wollman Exp";
34 #endif
35 
36 #include <sys/types.h>
37 
38 /*
39  * Cache the result of getdtablesize(), so we don't have to do an
40  * expensive system call every time.
41  */
42 /*
43  * XXX In FreeBSD 2.x, you can have the maximum number of open file
44  * descriptors be greater than FD_SETSIZE (which us 256 by default).
45  * This can lead to many RPC functions getting back an EINVAL from
46  * select() and bombing all over the place.
47  *
48  * You can apparently get select() to handle values larger than 256
49  * by patching the kernel, but most people aren't likely to know
50  * that. Clamping this function at 256 is a kludge, but it'll have to
51  * do until select()'s descriptor table size can be adjusted dynamically.
52  */
53 _rpc_dtablesize()
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