/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1985, 1988, 1993
 *      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.
 * -
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 * -
 * --Copyright--
 */

#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <stdarg.h>
#include <nsswitch.h>
#include <arpa/nameser.h>       /* XXX */
#include <resolv.h>             /* XXX */
#include "netdb_private.h"

void
_sethosthtent(int f, struct hostent_data *hed)
{
        if (!hed->hostf)
                hed->hostf = fopen(_PATH_HOSTS, "re");
        else
                rewind(hed->hostf);
        hed->stayopen = f;
}

void
_endhosthtent(struct hostent_data *hed)
{
        if (hed->hostf && !hed->stayopen) {
                (void) fclose(hed->hostf);
                hed->hostf = NULL;
        }
}

static int
gethostent_p(struct hostent *he, struct hostent_data *hed, int mapped,
    res_state statp)
{
        char *p, *bp, *ep;
        char *cp, **q;
        int af, len;
        char hostbuf[BUFSIZ + 1];

        if (!hed->hostf && !(hed->hostf = fopen(_PATH_HOSTS, "re"))) {
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                return (-1);
        }
 again:
        if (!(p = fgets(hostbuf, sizeof hostbuf, hed->hostf))) {
                RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
                return (-1);
        }
        if (*p == '#')
                goto again;
        cp = strpbrk(p, "#\n");
        if (cp != NULL)
                *cp = '\0';
        if (!(cp = strpbrk(p, " \t")))
                goto again;
        *cp++ = '\0';
        if (inet_pton(AF_INET6, p, hed->host_addr) > 0) {
                af = AF_INET6;
                len = IN6ADDRSZ;
        } else if (inet_pton(AF_INET, p, hed->host_addr) > 0) {
                if (mapped) {
                        _map_v4v6_address((char *)hed->host_addr,
                            (char *)hed->host_addr);
                        af = AF_INET6;
                        len = IN6ADDRSZ;
                } else {
                        af = AF_INET;
                        len = INADDRSZ;
                }
        } else {
                goto again;
        }
        hed->h_addr_ptrs[0] = (char *)hed->host_addr;
        hed->h_addr_ptrs[1] = NULL;
        he->h_addr_list = hed->h_addr_ptrs;
        he->h_length = len;
        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;
        if ((p = strpbrk(cp, " \t")) != NULL)
                *p++ = '\0';
        len = strlen(cp) + 1;
        if (ep - bp < len) {
                RES_SET_H_ERRNO(statp, NO_RECOVERY);
                return (-1);
        }
        strlcpy(bp, cp, ep - bp);
        bp += len;
        cp = p;
        while (cp && *cp) {
                if (*cp == ' ' || *cp == '\t') {
                        cp++;
                        continue;
                }
                if (q >= &hed->host_aliases[_MAXALIASES - 1])
                        break;
                if ((p = strpbrk(cp, " \t")) != NULL)
                        *p++ = '\0';
                len = strlen(cp) + 1;
                if (ep - bp < len)
                        break;
                strlcpy(bp, cp, ep - bp);
                *q++ = bp;
                bp += len;
                cp = p;
        }
        *q = NULL;
        RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
        return (0);
}

int
gethostent_r(struct hostent *hptr, char *buffer, size_t buflen,
    struct hostent **result, int *h_errnop)
{
        struct hostent_data *hed;
        struct hostent he;
        res_state statp;

        statp = __res_state();
        if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                *h_errnop = statp->res_h_errno;
                return (-1);
        }
        if ((hed = __hostent_data_init()) == NULL) {
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                *h_errnop = statp->res_h_errno;
                return (-1);
        }
        if (gethostent_p(&he, hed, statp->options & RES_USE_INET6, statp) != 0)
                return (-1);
        if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
                RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
                *h_errnop = statp->res_h_errno;
                return ((errno != 0) ? errno : -1);
        }
        *result = hptr;
        return (0);
}

struct hostent *
gethostent(void)
{
        struct hostdata *hd;
        struct hostent *rval;
        int ret_h_errno;

        if ((hd = __hostdata_init()) == NULL)
                return (NULL);
        if (gethostent_r(&hd->host, hd->data, sizeof(hd->data), &rval,
            &ret_h_errno) != 0)
                return (NULL);
        return (rval);
}

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

        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);
        }

        _sethosthtent(0, hed);
        while ((error = gethostent_p(&he, hed, 0, statp)) == 0) {
                if (he.h_addrtype != af)
                        continue;
                if (he.h_addrtype == AF_INET &&
                    statp->options & RES_USE_INET6) {
                        _map_v4v6_address(he.h_addr, he.h_addr);
                        he.h_length = IN6ADDRSZ;
                        he.h_addrtype = AF_INET6;
                }
                if (strcasecmp(he.h_name, name) == 0)
                        break;
                for (cp = he.h_aliases; *cp != 0; cp++)
                        if (strcasecmp(*cp, name) == 0)
                                goto found;
        }
found:
        _endhosthtent(hed);

        if (error != 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);
}

int
_ht_gethostbyaddr(void *rval, void *cb_data, va_list ap)
{
        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;
        int error;

        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);
        }

        _sethosthtent(0, hed);
        while ((error = gethostent_p(&he, hed, 0, statp)) == 0)
                if (he.h_addrtype == af && !bcmp(he.h_addr, addr, len)) {
                        if (he.h_addrtype == AF_INET &&
                            statp->options & RES_USE_INET6) {
                                _map_v4v6_address(he.h_addr, he.h_addr);
                                he.h_length = IN6ADDRSZ;
                                he.h_addrtype = AF_INET6;
                        }
                        break;
                }
        _endhosthtent(hed);

        if (error != 0)
                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);
}