/* $OpenBSD: rresvport.c,v 1.12 2019/06/28 13:32:42 deraadt Exp $ */
/*
 * Copyright (c) 1995, 1996, 1998 Theo de Raadt.  All rights reserved.
 * Copyright (c) 1983, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/socket.h>
#include <sys/stat.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <signal.h>
#include <fcntl.h>
#include <netdb.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <syslog.h>
#include <stdlib.h>
#include <netgroup.h>

int
rresvport(int *alport)
{
        return rresvport_af(alport, AF_INET);
}


int
rresvport_af(int *alport, int af)
{
        struct sockaddr_storage ss;
        struct sockaddr *sa;
        u_int16_t *portp;
        int s;

        bzero(&ss, sizeof ss);
        sa = (struct sockaddr *)&ss;

        switch (af) {
        case AF_INET:
                sa->sa_len = sizeof(struct sockaddr_in);
                portp = &((struct sockaddr_in *)sa)->sin_port;
                break;
        case AF_INET6:
                sa->sa_len = sizeof(struct sockaddr_in6);
                portp = &((struct sockaddr_in6 *)sa)->sin6_port;
                break;
        default:
                errno = EPFNOSUPPORT;
                return (-1);
        }
        sa->sa_family = af;
        
        s = socket(af, SOCK_STREAM, 0);
        if (s == -1)
                return (-1);

        *portp = htons(*alport);
        if (*alport < IPPORT_RESERVED - 1) {
                if (bind(s, sa, sa->sa_len) != -1)
                        return (s);
                if (errno != EADDRINUSE) {
                        (void)close(s);
                        return (-1);
                }
        }

        *portp = 0;
        sa->sa_family = af;
        if (bindresvport_sa(s, sa) == -1) {
                (void)close(s);
                return (-1);
        }
        *alport = ntohs(*portp);
        return (s);
}
DEF_WEAK(rresvport_af);