/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1994, Garrett Wollman
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE 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/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <stdarg.h>
#include <nsswitch.h>
#include <resolv.h>             /* XXX */
#ifdef YP
#include <rpc/rpc.h>
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#endif
#include "netdb_private.h"

#ifdef YP
static int
_gethostbynis(const char *name, char *map, int af, struct hostent *he,
    struct hostent_data *hed)
{
        char *p, *bp, *ep;
        char *cp, **q;
        char *result;
        int resultlen, size, addrok = 0;
        char *ypbuf;
        res_state statp;

        statp = __res_state();
        switch(af) {
        case AF_INET:
                size = NS_INADDRSZ;
                break;
        case AF_INET6:
                size = NS_IN6ADDRSZ;
                break;
        default:
                errno = EAFNOSUPPORT;
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                return (-1);
        }

        if (hed->yp_domain == (char *)NULL)
                if (yp_get_default_domain (&hed->yp_domain)) {
                        RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                        return (-1);
                }

        if (yp_match(hed->yp_domain, map, name, strlen(name), &result,
            &resultlen)) {
                RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
                return (-1);
        }

        /* avoid potential memory leak */
        ypbuf = alloca(resultlen + 2);
        bcopy(result, ypbuf, resultlen);
        ypbuf[resultlen] = '\0';
        free(result);
        result = ypbuf;

        if ((cp = strchr(result, '\n')))
                *cp = '\0';

        cp = strpbrk(result, " \t");
        *cp++ = '\0';
        he->h_addr_list = hed->h_addr_ptrs;
        he->h_addr = (char *)hed->host_addr;
        switch (af) {
        case AF_INET:
                addrok = inet_aton(result, (struct in_addr *)hed->host_addr);
                if (addrok != 1)
                        break;
                if (statp->options & RES_USE_INET6) {
                        _map_v4v6_address((char *)hed->host_addr,
                            (char *)hed->host_addr);
                        af = AF_INET6;
                        size = NS_IN6ADDRSZ;
                }
                break;
        case AF_INET6:
                addrok = inet_pton(af, result, hed->host_addr);
                break;
        }
        if (addrok != 1) {
                RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
                return (-1);
        }
        he->h_addr_list[1] = NULL;
        he->h_length = size;
        he->h_addrtype = af;
        while (*cp == ' ' || *cp == '\t')
                cp++;
        bp = hed->hostbuf;
        ep = hed->hostbuf + sizeof hed->hostbuf;
        he->h_name = bp;
        q = he->h_aliases = hed->host_aliases;
        p = strpbrk(cp, " \t");
        if (p != NULL)
                *p++ = '\0';
        size = strlen(cp) + 1;
        if (ep - bp < size) {
                RES_SET_H_ERRNO(statp, NO_RECOVERY);
                return (-1);
        }
        strlcpy(bp, cp, ep - bp);
        bp += size;
        cp = p;
        while (cp && *cp) {
                if (*cp == ' ' || *cp == '\t') {
                        cp++;
                        continue;
                }
                if (q >= &hed->host_aliases[_MAXALIASES - 1])
                        break;
                p = strpbrk(cp, " \t");
                if (p != NULL)
                        *p++ = '\0';
                size = strlen(cp) + 1;
                if (ep - bp < size)
                        break;
                strlcpy(bp, cp, ep - bp);
                *q++ = bp;
                bp += size;
                cp = p;
        }
        *q = NULL;
        return (0);
}

static int
_gethostbynisname_r(const char *name, int af, struct hostent *he,
    struct hostent_data *hed)
{
        char *map;

        switch (af) {
        case AF_INET:
                map = "hosts.byname";
                break;
        default:
                map = "ipnodes.byname";
                break;
        }
        return (_gethostbynis(name, map, af, he, hed));
}

static int
_gethostbynisaddr_r(const void *addr, socklen_t len, int af,
    struct hostent *he, struct hostent_data *hed)
{
        char *map;
        char numaddr[46];

        switch (af) {
        case AF_INET:
                map = "hosts.byaddr";
                break;
        default:
                map = "ipnodes.byaddr";
                break;
        }
        if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
                return (-1);
        return (_gethostbynis(numaddr, map, af, he, hed));
}
#endif /* YP */

int
_nis_gethostbyname(void *rval, void *cb_data, va_list ap)
{
#ifdef YP
        const char *name;
        int af;
        char *buffer;
        size_t buflen;
        int *errnop, *h_errnop;
        struct hostent *hptr, he;
        struct hostent_data *hed;
        res_state statp;

        name = va_arg(ap, const char *);
        af = va_arg(ap, int);
        hptr = va_arg(ap, struct hostent *);
        buffer = va_arg(ap, char *);
        buflen = va_arg(ap, size_t);
        errnop = va_arg(ap, int *);
        h_errnop = va_arg(ap, int *);

        *((struct hostent **)rval) = NULL;

        statp = __res_state();
        if ((hed = __hostent_data_init()) == NULL) {
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                *h_errnop = statp->res_h_errno;
                return (NS_NOTFOUND);
        }

        if (_gethostbynisname_r(name, af, &he, hed) != 0) {
                *h_errnop = statp->res_h_errno;
                return (NS_NOTFOUND);
        }
        if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
                *errnop = errno;
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                *h_errnop = statp->res_h_errno;
                return (NS_RETURN);
        }
        *((struct hostent **)rval) = hptr;
        return (NS_SUCCESS);
#else
        *((struct hostent **)rval) = NULL;
        return (NS_UNAVAIL);
#endif
}

int
_nis_gethostbyaddr(void *rval, void *cb_data, va_list ap)
{
#ifdef YP
        const void *addr;
        socklen_t len;
        int af;
        char *buffer;
        size_t buflen;
        int *errnop, *h_errnop;
        struct hostent *hptr, he;
        struct hostent_data *hed;
        res_state statp;

        addr = va_arg(ap, const void *);
        len = va_arg(ap, socklen_t);
        af = va_arg(ap, int);
        hptr = va_arg(ap, struct hostent *);
        buffer = va_arg(ap, char *);
        buflen = va_arg(ap, size_t);
        errnop = va_arg(ap, int *);
        h_errnop = va_arg(ap, int *);

        *((struct hostent **)rval) = NULL;

        statp = __res_state();
        if ((hed = __hostent_data_init()) == NULL) {
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                *h_errnop = statp->res_h_errno;
                return (NS_NOTFOUND);
        }

        if (_gethostbynisaddr_r(addr, len, af, &he, hed) != 0) {
                *h_errnop = statp->res_h_errno;
                return (NS_NOTFOUND);
        }
        if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
                *errnop = errno;
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                *h_errnop = statp->res_h_errno;
                return (NS_RETURN);
        }
        *((struct hostent **)rval) = hptr;
        return (NS_SUCCESS);
#else
        *((struct hostent **)rval) = NULL;
        return (NS_UNAVAIL);
#endif
}