lib/librpc/rpc/bindresvport.c

/*
 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
 * unrestricted use provided that this legend is included on all tape
 * media and as a part of the software program in whole or part.  Users
 * may copy or modify Sun RPC without charge, but are not authorized
 * to license or distribute it to anyone else except as part of a product or
 * program developed by the user.
 *
 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 *
 * Sun RPC is provided with no support and without any obligation on the
 * part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 *
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
 * OR ANY PART THEREOF.
 *
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 *
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 */

#if defined(LIBC_SCCS) && !defined(lint)
/*static char *sccsid = "from: @(#)bindresvport.c 1.8 88/02/08 SMI";*/
/*static char *sccsid = "from: @(#)bindresvport.c       2.2 88/07/29 4.0 RPCSRC";*/
static char *rcsid = "$Id: bindresvport.c,v 1.3 1993/08/26 00:53:14 jtc Exp $";
#endif

/*
 * Copyright (c) 1987 by Sun Microsystems, Inc.
 */

#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 600
#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,
                    (struct sockaddr *)sin, sizeof(struct sockaddr_in));
        }
        return (res);
}