bindresvport.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char *sccsid = "@(#)bindresvport.c	4.1      ULTRIX  7/3/90";
#endif lint

/************************************************************************
 *                                                                      *
 *                      Copyright (c) 1986 by                           *
 *              Digital Equipment Corporation, Maynard, MA              *
 *                      All rights reserved.                            *
 *                                                                      *
 *   This software is furnished under a license and may be used and     *
 *   copied  only  in accordance with the terms of such license and     *
 *   with the  inclusion  of  the  above  copyright  notice.   This     *
 *   software  or  any  other copies thereof may not be provided or     *
 *   otherwise made available to any other person.  No title to and     *
 *   ownership of the software is hereby transferred.                   *
 *                                                                      *
 *   This software is  derived  from  software  received  from  the     *
 *   University    of   California,   Berkeley,   and   from   Bell     *
 *   Laboratories.  Use, duplication, or disclosure is  subject  to     *
 *   restrictions  under  license  agreements  with  University  of     *
 *   California and with AT&T.                                          *
 *                                                                      *
 *   The information in this software is subject to change  without     *
 *   notice  and should not be construed as a commitment by Digital     *
 *   Equipment Corporation.                                             *
 *                                                                      *
 *   Digital assumes no responsibility for the use  or  reliability     *
 *   of its software on equipment which is not supplied by Digital.     *
 *                                                                      *
 ************************************************************************/


/*
 * Copyright (c) 1987 by Sun Microsystems, Inc.
 */
/*      change log
 *      04/12/89  jhw   Synced code to SUN V4.0
 */

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/socket.h>
#include <netinet/in.h>

/*
 * Bind a socket to a privileged IP port
 */
bindresvport(sd, sin)
	int sd;
	struct sockaddr_in *sin;
{
	int res;
	static short port;
	struct sockaddr_in myaddr;
	extern int errno;
	int i;

#define STARTPORT 825
#define ENDPORT (IPPORT_RESERVED - 1)
#define NPORTS	(ENDPORT - STARTPORT + 1)

	if (sin == (struct sockaddr_in *)0) {
		sin = &myaddr;
		bzero(sin, sizeof (*sin));
		sin->sin_family = AF_INET;
	} else if (sin->sin_family != AF_INET) {
		errno = EPFNOSUPPORT;
		return (-1);
	}
	if (port == 0) {
		port = (getpid() % NPORTS) + STARTPORT;
	}
	res = -1;
	errno = EADDRINUSE;
	for (i = 0; i < NPORTS && res < 0 && errno == EADDRINUSE; i++) {
		sin->sin_port = htons(port++);
		if (port > ENDPORT) {
			port = STARTPORT;
		}
		res = bind(sd, sin, sizeof(struct sockaddr_in));
	}
	return (res);
}