1 files changed, 725 insertions, 250 deletions

diff --git a/src/lib/libc/net/gethostnamadr.c b/src/lib/libc/net/gethostnamadr.c
index ec3f14a900..d49b9cdd7d 100644
--- a/src/lib/libc/net/gethostnamadr.c
+++ b/src/lib/libc/net/gethostnamadr.c
@@ -1,5 +1,4 @@
-/*      $NetBSD: gethostnamadr.c,v 1.13 1995/05/21 16:21:14 mycroft Exp $       */
-
+/*      $OpenBSD: gethostnamadr.c,v 1.72 2007/10/11 18:36:41 jakob Exp $ */
 /*-
  * Copyright (c) 1985, 1988, 1993
  *      The Regents of the University of California.  All rights reserved.
@@ -12,11 +11,7 @@
  * 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. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *      This product includes software developed by the University of
- *      California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
+ * 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.
  *
@@ -53,15 +48,6 @@
  * --Copyright--
  */
 
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
-static char rcsid[] = "$Id: gethnamaddr.c,v 4.9.1.1 1993/05/02 22:43:03 vixie Rel ";
-#else
-static char rcsid[] = "$NetBSD: gethostnamadr.c,v 1.13 1995/05/21 16:21:14 mycroft Exp $";
-#endif
-#endif /* LIBC_SCCS and not lint */
-
 #include <sys/param.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -73,11 +59,17 @@ static char rcsid[] = "$NetBSD: gethostnamadr.c,v 1.13 1995/05/21 16:21:14 mycro
 #include <ctype.h>
 #include <errno.h>
 #include <string.h>
+#include <syslog.h>
+#include <stdlib.h>
 #ifdef YP
 #include <rpc/rpc.h>
-#include <rpcsvc/yp_prot.h>
+#include <rpcsvc/yp.h>
 #include <rpcsvc/ypclnt.h>
+#include "ypinternal.h"
 #endif
+#include "thread_private.h"
+
+#define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
 
 #define MAXALIASES      35
 #define MAXADDRS        35
@@ -91,47 +83,101 @@ static char *__ypdomain;
 static struct hostent host;
 static char *host_aliases[MAXALIASES];
 static char hostbuf[BUFSIZ+1];
-static struct in_addr host_addr;
+static union {
+        struct in_addr _host_in_addr;
+        u_char _host_addr[16];          /* IPv4 or IPv6 */
+} _host_addr_u;
+#define host_addr _host_addr_u._host_addr
 static FILE *hostf = NULL;
 static int stayopen = 0;
 
-#if PACKETSZ > 1024
-#define MAXPACKET       PACKETSZ
-#else
-#define MAXPACKET       1024
+static void map_v4v6_address(const char *src, char *dst);
+static void map_v4v6_hostent(struct hostent *hp, char **bp, char *);
+
+#ifdef RESOLVSORT
+static void addrsort(char **, int);
 #endif
 
+int _hokchar(const char *);
+
+static const char AskedForGot[] =
+                          "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
+
+#define MAXPACKET       (64*1024)
+
 typedef union {
         HEADER hdr;
         u_char buf[MAXPACKET];
 } querybuf;
 
 typedef union {
-    int32_t al;
-    char ac;
+        int32_t al;
+        char ac;
 } align;
 
-static int qcomp __P((struct in_addr **, struct in_addr **));
-static struct hostent *getanswer __P((querybuf *, int, int));
+static struct hostent *getanswer(const querybuf *, int, const char *, int);
 
 extern int h_errno;
 
+int
+_hokchar(const char *p)
+{
+        char c;
+
+        /*
+         * Many people do not obey RFC 822 and 1035.  The valid
+         * characters are a-z, A-Z, 0-9, '-' and . But the others
+         * tested for below can happen, and we must be more permissive
+         * than the resolver until those idiots clean up their act.
+         * We let '/' through, but not '..'
+         */
+        while ((c = *p++)) {
+                if (('a' <= c && c <= 'z') ||
+                    ('A' <= c && c <= 'Z') ||
+                    ('0' <= c && c <= '9'))
+                        continue;
+                if (strchr("-_/", c))
+                        continue;
+                if (c == '.' && *p != '.')
+                        continue;
+                return 0;
+        }
+        return 1;
+}
+
 static struct hostent *
-getanswer(answer, anslen, iquery)
-        querybuf *answer;
-        int anslen;
-        int iquery;
+getanswer(const querybuf *answer, int anslen, const char *qname, int qtype)
 {
-        register HEADER *hp;
-        register u_char *cp;
-        register int n;
-        u_char *eom;
-        char *bp, **ap;
-        int type, class, buflen, ancount, qdcount;
-        int haveanswer, getclass = C_ANY;
-        char **hap;
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+        const HEADER *hp;
+        const u_char *cp, *eom;
+        char tbuf[MAXDNAME];
+        char *bp, **ap, **hap, *ep;
+        int type, class, ancount, qdcount, n;
+        int haveanswer, had_error, toobig = 0;
+        const char *tname;
+        int (*name_ok)(const char *);
 
+        tname = qname;
+        host.h_name = NULL;
         eom = answer->buf + anslen;
+        switch (qtype) {
+        case T_A:
+        case T_AAAA:
+#ifdef USE_RESOLV_NAME_OK
+                name_ok = res_hnok;
+                break;
+#endif
+        case T_PTR:
+#ifdef USE_RESOLV_NAME_OK
+                name_ok = res_dnok;
+#else
+                name_ok = _hokchar;
+#endif
+                break;
+        default:
+                return (NULL);
+        }
         /*
          * find first satisfactory answer
          */
@@ -139,31 +185,27 @@ getanswer(answer, anslen, iquery)
         ancount = ntohs(hp->ancount);
         qdcount = ntohs(hp->qdcount);
         bp = hostbuf;
-        buflen = sizeof(hostbuf);
-        cp = answer->buf + sizeof(HEADER);
-        if (qdcount) {
-                if (iquery) {
-                        if ((n = dn_expand((u_char *)answer->buf,
-                            (u_char *)eom, (u_char *)cp, (u_char *)bp,
-                            buflen)) < 0) {
-                                h_errno = NO_RECOVERY;
-                                return ((struct hostent *) NULL);
-                        }
-                        cp += n + QFIXEDSZ;
-                        host.h_name = bp;
-                        n = strlen(bp) + 1;
-                        bp += n;
-                        buflen -= n;
-                } else
-                        cp += __dn_skipname(cp, eom) + QFIXEDSZ;
-                while (--qdcount > 0)
-                        cp += __dn_skipname(cp, eom) + QFIXEDSZ;
-        } else if (iquery) {
-                if (hp->aa)
-                        h_errno = HOST_NOT_FOUND;
-                else
-                        h_errno = TRY_AGAIN;
-                return ((struct hostent *) NULL);
+        ep = hostbuf + sizeof hostbuf;
+        cp = answer->buf + HFIXEDSZ;
+        if (qdcount != 1) {
+                h_errno = NO_RECOVERY;
+                return (NULL);
+        }
+        n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
+        if ((n < 0) || !(*name_ok)(bp)) {
+                h_errno = NO_RECOVERY;
+                return (NULL);
+        }
+        cp += n + QFIXEDSZ;
+        if (qtype == T_A || qtype == T_AAAA) {
+                /* res_send() has already verified that the query name is the
+                 * same as the one we sent; this just gets the expanded name
+                 * (i.e., with the succeeding search-domain tacked on).
+                 */
+                host.h_name = bp;
+                bp += strlen(bp) + 1;           /* for the \0 */
+                /* The qname can be abbreviated, but h_name is now absolute. */
+                qname = host.h_name;
         }
         ap = host_aliases;
         *ap = NULL;
@@ -172,103 +214,323 @@ getanswer(answer, anslen, iquery)
         *hap = NULL;
         host.h_addr_list = h_addr_ptrs;
         haveanswer = 0;
-        while (--ancount >= 0 && cp < eom) {
-                if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom,
-                    (u_char *)cp, (u_char *)bp, buflen)) < 0)
+        had_error = 0;
+        while (ancount-- > 0 && cp < eom && !had_error) {
+                size_t len;
+
+                n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
+                if ((n < 0) || !(*name_ok)(bp)) {
+                        had_error++;
+                        continue;
+                }
+                cp += n;                        /* name */
+                if (cp >= eom)
                         break;
-                cp += n;
                 type = _getshort(cp);
-                cp += sizeof(u_int16_t);
+                cp += INT16SZ;                  /* type */
+                if (cp >= eom)
+                        break;
                 class = _getshort(cp);
-                cp += sizeof(u_int16_t) + sizeof(u_int32_t);
+                cp += INT16SZ + INT32SZ;        /* class, TTL */
+                if (cp >= eom)
+                        break;
                 n = _getshort(cp);
-                cp += sizeof(u_int16_t);
-                if (type == T_CNAME) {
+                cp += INT16SZ;                  /* len */
+                if (cp >= eom)
+                        break;
+                if (type == T_SIG || type == T_RRSIG) {
+                        /* XXX - ignore signatures as we don't use them yet */
                         cp += n;
-                        if (ap >= &host_aliases[MAXALIASES-1])
-                                continue;
-                        *ap++ = bp;
-                        n = strlen(bp) + 1;
-                        bp += n;
-                        buflen -= n;
                         continue;
                 }
-                if (iquery && type == T_PTR) {
-                        if ((n = dn_expand((u_char *)answer->buf,
-                            (u_char *)eom, (u_char *)cp, (u_char *)bp,
-                            buflen)) < 0)
-                                break;
+                if (class != C_IN) {
+                        /* XXX - debug? syslog? */
                         cp += n;
+                        continue;               /* XXX - had_error++ ? */
+                }
+                if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
+                        if (ap >= &host_aliases[MAXALIASES-1])
+                                continue;
+                        n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
+                        if ((n < 0) || !(*name_ok)(tbuf)) {
+                                had_error++;
+                                continue;
+                        }
+                        cp += n;
+                        /* Store alias. */
+                        *ap++ = bp;
+                        bp += strlen(bp) + 1;   /* for the \0 */
+                        /* Get canonical name. */
+                        len = strlen(tbuf) + 1; /* for the \0 */
+                        if (len > ep - bp) {
+                                had_error++;
+                                continue;
+                        }
+                        strlcpy(bp, tbuf, ep - bp);
                         host.h_name = bp;
-                        return(&host);
+                        bp += len;
+                        continue;
                 }
-                if (iquery || type != T_A)  {
-#ifdef DEBUG
-                        if (_res.options & RES_DEBUG)
-                                printf("unexpected answer type %d, size %d\n",
-                                        type, n);
+                if (qtype == T_PTR && type == T_CNAME) {
+                        n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
+#ifdef USE_RESOLV_NAME_OK
+                        if ((n < 0) || !res_hnok(tbuf)) {
+#else
+                        if ((n < 0) || !_hokchar(tbuf)) {
 #endif
+                                had_error++;
+                                continue;
+                        }
                         cp += n;
+                        /* Get canonical name. */
+                        len = strlen(tbuf) + 1; /* for the \0 */
+                        if (len > ep - bp) {
+                                had_error++;
+                                continue;
+                        }
+                        strlcpy(bp, tbuf, ep - bp);
+                        tname = bp;
+                        bp += len;
                         continue;
                 }
-                if (haveanswer) {
-                        if (n != host.h_length) {
+                if (type != qtype) {
+                        syslog(LOG_NOTICE|LOG_AUTH,
+               "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
+                               qname, p_class(C_IN), p_type(qtype),
+                               p_type(type));
+                        cp += n;
+                        continue;               /* XXX - had_error++ ? */
+                }
+                switch (type) {
+                case T_PTR:
+                        if (strcasecmp(tname, bp) != 0) {
+                                syslog(LOG_NOTICE|LOG_AUTH,
+                                       AskedForGot, qname, bp);
                                 cp += n;
-                                continue;
+                                continue;       /* XXX - had_error++ ? */
+                        }
+                        n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
+#ifdef USE_RESOLV_NAME_OK
+                        if ((n < 0) || !res_hnok(bp)) {
+#else
+                        if ((n < 0) || !_hokchar(bp)) {
+#endif
+                                had_error++;
+                                break;
+                        }
+#if MULTI_PTRS_ARE_ALIASES
+                        cp += n;
+                        if (!haveanswer)
+                                host.h_name = bp;
+                        else if (ap < &host_aliases[MAXALIASES-1])
+                                *ap++ = bp;
+                        else
+                                n = -1;
+                        if (n != -1) {
+                                n = strlen(bp) + 1;     /* for the \0 */
+                                bp += n;
+                        }
+                        break;
+#else
+                        host.h_name = bp;
+                        if (_resp->options & RES_USE_INET6) {
+                                n = strlen(bp) + 1;     /* for the \0 */
+                                bp += n;
+                                map_v4v6_hostent(&host, &bp, ep);
+                        }
+                        h_errno = NETDB_SUCCESS;
+                        return (&host);
+#endif
+                case T_A:
+                case T_AAAA:
+                        if (strcasecmp(host.h_name, bp) != 0) {
+                                syslog(LOG_NOTICE|LOG_AUTH,
+                                       AskedForGot, host.h_name, bp);
+                                cp += n;
+                                continue;       /* XXX - had_error++ ? */
                         }
-                        if (class != getclass) {
+                        if (n != host.h_length) {
                                 cp += n;
                                 continue;
                         }
-                } else {
-                        host.h_length = n;
-                        getclass = class;
-                        host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
-                        if (!iquery) {
+                        if (type == T_AAAA) {
+                                struct in6_addr in6;
+                                memcpy(&in6, cp, IN6ADDRSZ);
+                                if (IN6_IS_ADDR_V4MAPPED(&in6)) {
+                                        cp += n;
+                                        continue;
+                                }
+                        }
+                        if (!haveanswer) {
                                 host.h_name = bp;
-                                bp += strlen(bp) + 1;
+                                bp += strlen(bp) + 1;   /* for the \0 */
                         }
-                }
 
-                bp += sizeof(align) - ((u_long)bp % sizeof(align));
+                        bp += sizeof(align) - ((u_long)bp % sizeof(align));
 
-                if (bp + n >= &hostbuf[sizeof(hostbuf)]) {
+                        if (bp + n >= &hostbuf[sizeof hostbuf]) {
 #ifdef DEBUG
-                        if (_res.options & RES_DEBUG)
-                                printf("size (%d) too big\n", n);
+                                if (_resp->options & RES_DEBUG)
+                                        printf("size (%d) too big\n", n);
 #endif
+                                had_error++;
+                                continue;
+                        }
+                        if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
+                                if (!toobig++)
+#ifdef DEBUG
+                                        if (_resp->options & RES_DEBUG)
+                                                printf("Too many addresses (%d)\n", MAXADDRS);
+#endif
+                                cp += n;
+                                continue;
+                        }
+                        bcopy(cp, *hap++ = bp, n);
+                        bp += n;
+                        cp += n;
                         break;
                 }
-                bcopy(cp, *hap++ = bp, n);
-                bp +=n;
-                cp += n;
-                haveanswer++;
+                if (!had_error)
+                        haveanswer++;
         }
         if (haveanswer) {
                 *ap = NULL;
                 *hap = NULL;
-                if (_res.nsort) {
-                        qsort(host.h_addr_list, haveanswer,
-                            sizeof(struct in_addr),
-                            (int (*)__P((const void *, const void *)))qcomp);
+# if defined(RESOLVSORT)
+                /*
+                 * Note: we sort even if host can take only one address
+                 * in its return structures - should give it the "best"
+                 * address in that case, not some random one
+                 */
+                if (_resp->nsort && haveanswer > 1 && qtype == T_A)
+                        addrsort(h_addr_ptrs, haveanswer);
+# endif /*RESOLVSORT*/
+                if (!host.h_name) {
+                        size_t len;
+
+                        len = strlen(qname) + 1;
+                        if (len > ep - bp)      /* for the \0 */
+                                goto try_again;
+                        strlcpy(bp, qname, ep - bp);
+                        host.h_name = bp;
+                        bp += len;
                 }
+                if (_resp->options & RES_USE_INET6)
+                        map_v4v6_hostent(&host, &bp, ep);
+                h_errno = NETDB_SUCCESS;
                 return (&host);
-        } else {
-                h_errno = TRY_AGAIN;
-                return ((struct hostent *) NULL);
         }
+ try_again:
+        h_errno = TRY_AGAIN;
+        return (NULL);
 }
 
+#ifdef notyet
+/*
+ * XXX This is an extremely bogus implementation.
+ *
+ * FreeBSD has this interface:
+ *    int gethostbyaddr_r(const char *addr, int len, int type,
+ *             struct hostent *result, struct hostent_data *buffer)
+ */
+
+struct hostent *
+gethostbyname_r(const char *name, struct hostent *hp, char *buf, int buflen,
+    int *errorp)
+{
+        struct hostent *res;
+
+        res = gethostbyname(name);
+        *errorp = h_errno;
+        if (res == NULL)
+                return NULL;
+        memcpy(hp, res, sizeof *hp); /* XXX not sufficient */
+        return hp;
+}
+
+/*
+ * XXX This is an extremely bogus implementation.
+ */
 struct hostent *
-gethostbyname(name)
-        const char *name;
+gethostbyaddr_r(const char *addr, int len, int af, struct hostent *he,
+    char *buf, int buflen, int *errorp)
 {
-        querybuf buf;
-        register const char *cp;
-        int n, i;
-        extern struct hostent *_gethtbyname(), *_yp_gethtbyname();
-        register struct hostent *hp;
+        struct hostent * res;
+
+        res = gethostbyaddr(addr, len, af);
+        *errorp = h_errno;
+        if (res == NULL)
+                return NULL;
+        memcpy(he, res, sizeof *he); /* XXX not sufficient */
+        return he;
+}
+
+/* XXX RFC2133 expects a gethostbyname2_r() -- unimplemented */
+#endif
+
+struct hostent *
+gethostbyname(const char *name)
+{
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+        struct hostent *hp;
+        extern struct hostent *_gethtbyname2(const char *, int);
+
+        if (_res_init(0) == -1)
+                hp = _gethtbyname2(name, AF_INET);
+
+        else if (_resp->options & RES_USE_INET6) {
+                hp = gethostbyname2(name, AF_INET6);
+                if (hp == NULL)
+                        hp = gethostbyname2(name, AF_INET);
+        }
+        else
+                hp = gethostbyname2(name, AF_INET);
+        return hp;
+}
+
+struct hostent *
+gethostbyname2(const char *name, int af)
+{
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+        querybuf *buf;
+        const char *cp;
+        char *bp, *ep;
+        int n, size, type, i;
+        struct hostent *hp;
         char lookups[MAXDNSLUS];
+        extern struct hostent *_gethtbyname2(const char *, int);
+#ifdef YP
+        extern struct hostent *_yp_gethtbyname(const char *);
+#endif
+
+        if (_res_init(0) == -1)
+                return (_gethtbyname2(name, af));
+
+        switch (af) {
+        case AF_INET:
+                size = INADDRSZ;
+                type = T_A;
+                break;
+        case AF_INET6:
+                size = IN6ADDRSZ;
+                type = T_AAAA;
+                break;
+        default:
+                h_errno = NETDB_INTERNAL;
+                errno = EAFNOSUPPORT;
+                return (NULL);
+        }
+
+        host.h_addrtype = af;
+        host.h_length = size;
+
+        /*
+         * if there aren't any dots, it could be a user-level alias.
+         * this is also done in res_query() since we are not the only
+         * function that looks up host names.
+         */
+        if (!strchr(name, '.') && (cp = __hostalias(name)))
+                name = cp;
 
         /*
          * disallow names consisting only of digits/dots, unless
@@ -284,122 +546,229 @@ gethostbyname(name)
                                  * Fake up a hostent as if we'd actually
                                  * done a lookup.
                                  */
-                                if (!inet_aton(name, &host_addr)) {
+                                if (inet_pton(af, name, host_addr) <= 0) {
                                         h_errno = HOST_NOT_FOUND;
-                                        return((struct hostent *) NULL);
+                                        return (NULL);
                                 }
-                                host.h_name = (char *)name;
+                                strlcpy(hostbuf, name, MAXHOSTNAMELEN);
+                                bp = hostbuf + MAXHOSTNAMELEN;
+                                ep = hostbuf + sizeof(hostbuf);
+                                host.h_name = hostbuf;
                                 host.h_aliases = host_aliases;
                                 host_aliases[0] = NULL;
-                                host.h_addrtype = AF_INET;
-                                host.h_length = sizeof(u_int32_t);
-                                h_addr_ptrs[0] = (char *)&host_addr;
+                                h_addr_ptrs[0] = (char *)host_addr;
                                 h_addr_ptrs[1] = NULL;
                                 host.h_addr_list = h_addr_ptrs;
+                                if (_resp->options & RES_USE_INET6)
+                                        map_v4v6_hostent(&host, &bp, ep);
+                                h_errno = NETDB_SUCCESS;
                                 return (&host);
                         }
                         if (!isdigit(*cp) && *cp != '.') 
                                 break;
                 }
+        if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
+            name[0] == ':')
+                for (cp = name;; ++cp) {
+                        if (!*cp) {
+                                if (*--cp == '.')
+                                        break;
+                                /*
+                                 * All-IPv6-legal, no dot at the end.
+                                 * Fake up a hostent as if we'd actually
+                                 * done a lookup.
+                                 */
+                                if (inet_pton(af, name, host_addr) <= 0) {
+                                        h_errno = HOST_NOT_FOUND;
+                                        return (NULL);
+                                }
+                                strlcpy(hostbuf, name, MAXHOSTNAMELEN);
+                                bp = hostbuf + MAXHOSTNAMELEN;
+                                ep = hostbuf + sizeof(hostbuf);
+                                host.h_name = hostbuf;
+                                host.h_aliases = host_aliases;
+                                host_aliases[0] = NULL;
+                                h_addr_ptrs[0] = (char *)host_addr;
+                                h_addr_ptrs[1] = NULL;
+                                host.h_addr_list = h_addr_ptrs;
+                                h_errno = NETDB_SUCCESS;
+                                return (&host);
+                        }
+                        if (!isxdigit(*cp) && *cp != ':' && *cp != '.') 
+                                break;
+                }
 
-        if ((_res.options & RES_INIT) == 0 && res_init() == -1)
-                return (_gethtbyname(name));
-
-        bcopy(_res.lookups, lookups, sizeof lookups);
+        bcopy(_resp->lookups, lookups, sizeof lookups);
         if (lookups[0] == '\0')
-                strncpy(lookups, "bf", sizeof lookups);
+                strlcpy(lookups, "bf", sizeof lookups);
 
         hp = (struct hostent *)NULL;
         for (i = 0; i < MAXDNSLUS && hp == NULL && lookups[i]; i++) {
                 switch (lookups[i]) {
 #ifdef YP
                 case 'y':
-                        hp = _yp_gethtbyname(name);
+                        /* YP only supports AF_INET. */
+                        if (af == AF_INET)
+                                hp = _yp_gethtbyname(name);
                         break;
 #endif
                 case 'b':
-                        if ((n = res_search(name, C_IN, T_A, buf.buf,
-                            sizeof(buf))) < 0) {
+                        buf = malloc(sizeof(*buf));
+                        if (buf == NULL)
+                                break;
+                        if ((n = res_search(name, C_IN, type, buf->buf,
+                            sizeof(buf->buf))) < 0) {
+                                free(buf);
 #ifdef DEBUG
-                                if (_res.options & RES_DEBUG)
+                                if (_resp->options & RES_DEBUG)
                                         printf("res_search failed\n");
 #endif
                                 break;
                         }
-                        hp = getanswer(&buf, n, 0);
+                        hp = getanswer(buf, n, name, type);
+                        free(buf);
                         break;
                 case 'f':
-                        hp = _gethtbyname(name);
+                        hp = _gethtbyname2(name, af);
                         break;
                 }
         }
+        /* XXX h_errno not correct in all cases... */
         return (hp);
 }
 
 struct hostent *
-gethostbyaddr(addr, len, type)
-        const char *addr;
-        int len, type;
+gethostbyaddr(const void *addr, socklen_t len, int af)
 {
-        int n, i;
-        querybuf buf;
-        register struct hostent *hp;
-        char qbuf[MAXDNAME];
-        extern struct hostent *_gethtbyaddr(), *_yp_gethtbyaddr();
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+        const u_char *uaddr = (const u_char *)addr;
+        int n, size, i;
+        querybuf *buf;
+        struct hostent *hp;
+        char qbuf[MAXDNAME+1], *qp, *ep;
         char lookups[MAXDNSLUS];
+        struct hostent *res;
+        extern struct hostent *_gethtbyaddr(const void *, socklen_t, int);
+#ifdef YP
+        extern struct hostent *_yp_gethtbyaddr(const void *);
+#endif
         
-        if (type != AF_INET)
-                return ((struct hostent *) NULL);
-        (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
-                ((unsigned)addr[3] & 0xff),
-                ((unsigned)addr[2] & 0xff),
-                ((unsigned)addr[1] & 0xff),
-                ((unsigned)addr[0] & 0xff));
-
-        if ((_res.options & RES_INIT) == 0 && res_init() == -1)
-                return (_gethtbyaddr(addr, len, type));
-
-        bcopy(_res.lookups, lookups, sizeof lookups);
+        if (_res_init(0) == -1) {
+                res = _gethtbyaddr(addr, len, af);
+                return (res);
+        }
+
+        if (af == AF_INET6 && len == IN6ADDRSZ &&
+            (IN6_IS_ADDR_LINKLOCAL((struct in6_addr *)uaddr) ||
+             IN6_IS_ADDR_SITELOCAL((struct in6_addr *)uaddr))) {
+                h_errno = HOST_NOT_FOUND;
+                return (NULL);
+        }
+        if (af == AF_INET6 && len == IN6ADDRSZ &&
+            (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)uaddr) ||
+             IN6_IS_ADDR_V4COMPAT((struct in6_addr *)uaddr))) {
+                /* Unmap. */
+                uaddr += IN6ADDRSZ - INADDRSZ;
+                af = AF_INET;
+                len = INADDRSZ;
+        }
+        switch (af) {
+        case AF_INET:
+                size = INADDRSZ;
+                break;
+        case AF_INET6:
+                size = IN6ADDRSZ;
+                break;
+        default:
+                errno = EAFNOSUPPORT;
+                h_errno = NETDB_INTERNAL;
+                return (NULL);
+        }
+        if (size != len) {
+                errno = EINVAL;
+                h_errno = NETDB_INTERNAL;
+                return (NULL);
+        }
+        ep = qbuf + sizeof(qbuf);
+        switch (af) {
+        case AF_INET:
+                (void) snprintf(qbuf, sizeof qbuf, "%u.%u.%u.%u.in-addr.arpa",
+                    (uaddr[3] & 0xff), (uaddr[2] & 0xff),
+                    (uaddr[1] & 0xff), (uaddr[0] & 0xff));
+                break;
+        case AF_INET6:
+                qp = qbuf;
+                for (n = IN6ADDRSZ - 1; n >= 0; n--) {
+                        i = snprintf(qp, ep - qp, "%x.%x.",
+                            uaddr[n] & 0xf, (uaddr[n] >> 4) & 0xf);
+                        if (i <= 0 || i >= ep - qp) {
+                                errno = EINVAL;
+                                h_errno = NETDB_INTERNAL;
+                                return (NULL);
+                        }
+                        qp += i;
+                }
+                strlcpy(qp, "ip6.arpa", ep - qp);
+                break;
+        }
+
+        bcopy(_resp->lookups, lookups, sizeof lookups);
         if (lookups[0] == '\0')
-                strncpy(lookups, "bf", sizeof lookups);
+                strlcpy(lookups, "bf", sizeof lookups);
 
         hp = (struct hostent *)NULL;
         for (i = 0; i < MAXDNSLUS && hp == NULL && lookups[i]; i++) {
                 switch (lookups[i]) {
 #ifdef YP
                 case 'y':
-                        hp = _yp_gethtbyaddr(addr, len, type);
+                        /* YP only supports AF_INET. */
+                        if (af == AF_INET)
+                                hp = _yp_gethtbyaddr(uaddr);
                         break;
 #endif
                 case 'b':
-                        n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf));
+                        buf = malloc(sizeof(*buf));
+                        if (!buf)
+                                break;
+                        n = res_query(qbuf, C_IN, T_PTR, buf->buf,
+                            sizeof(buf->buf));
                         if (n < 0) {
+                                free(buf);
 #ifdef DEBUG
-                                if (_res.options & RES_DEBUG)
+                                if (_resp->options & RES_DEBUG)
                                         printf("res_query failed\n");
 #endif
                                 break;
                         }
-                        hp = getanswer(&buf, n, 1);
-                        if (hp == NULL)
+                        if (!(hp = getanswer(buf, n, qbuf, T_PTR))) {
+                                free(buf);
                                 break;
-                        hp->h_addrtype = type;
+                        }
+                        free(buf);
+                        hp->h_addrtype = af;
                         hp->h_length = len;
-                        h_addr_ptrs[0] = (char *)&host_addr;
-                        h_addr_ptrs[1] = (char *)0;
-                        host_addr = *(struct in_addr *)addr;
+                        bcopy(uaddr, host_addr, len);
+                        h_addr_ptrs[0] = (char *)host_addr;
+                        h_addr_ptrs[1] = NULL;
+                        if (af == AF_INET && (_resp->options & RES_USE_INET6)) {
+                                map_v4v6_address((char*)host_addr,
+                                    (char*)host_addr);
+                                hp->h_addrtype = AF_INET6;
+                                hp->h_length = IN6ADDRSZ;
+                        }
+                        h_errno = NETDB_SUCCESS;
                         break;
                 case 'f':
-                        hp = _gethtbyaddr(addr, len, type);
+                        hp = _gethtbyaddr(uaddr, len, af);
                         break;
                 }
         }
+        /* XXX h_errno not correct in all cases... */
         return (hp);
 }
 
 void
-_sethtent(f)
-        int f;
+_sethtent(int f)
 {
         if (hostf == NULL)
                 hostf = fopen(_PATH_HOSTS, "r" );
@@ -409,7 +778,7 @@ _sethtent(f)
 }
 
 void
-_endhtent()
+_endhtent(void)
 {
         if (hostf && !stayopen) {
                 (void) fclose(hostf);
@@ -417,40 +786,66 @@ _endhtent()
         }
 }
 
-struct hostent *
-_gethtent()
+static struct hostent *
+_gethtent(void)
 {
-        char *p;
-        register char *cp, **q;
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+        char *p, *cp, **q;
+        int af;
+        size_t len;
 
-        if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL)
+        if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
+                h_errno = NETDB_INTERNAL;
                 return (NULL);
-again:
-        if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL)
+        }
+ again:
+        if ((p = fgetln(hostf, &len)) == NULL) {
+                h_errno = HOST_NOT_FOUND;
                 return (NULL);
-        if (*p == '#')
+        }
+        if (p[len-1] == '\n')
+                len--;
+        if (len >= sizeof(hostbuf) || len == 0)
                 goto again;
-        cp = strpbrk(p, "#\n");
-        if (cp == NULL)
+        p = memcpy(hostbuf, p, len);
+        hostbuf[len] = '\0';
+        if (*p == '#')
                 goto again;
-        *cp = '\0';
-        cp = strpbrk(p, " \t");
-        if (cp == NULL)
+        if ((cp = strchr(p, '#')))
+                *cp = '\0';
+        if (!(cp = strpbrk(p, " \t")))
                 goto again;
         *cp++ = '\0';
-        /* THIS STUFF IS INTERNET SPECIFIC */
-        h_addr_ptrs[0] = (char *)&host_addr;
+        if (inet_pton(AF_INET6, p, host_addr) > 0) {
+                af = AF_INET6;
+                len = IN6ADDRSZ;
+        } else if (inet_pton(AF_INET, p, host_addr) > 0) {
+                if (_resp->options & RES_USE_INET6) {
+                        map_v4v6_address((char*)host_addr, (char*)host_addr);
+                        af = AF_INET6;
+                        len = IN6ADDRSZ;
+                } else {
+                        af = AF_INET;
+                        len = INADDRSZ;
+                }
+        } else {
+                goto again;
+        }
+        /* if this is not something we're looking for, skip it. */
+        if (host.h_addrtype != AF_UNSPEC && host.h_addrtype != af)
+                goto again;
+        if (host.h_length != 0 && host.h_length != len)
+                goto again;
+        h_addr_ptrs[0] = (char *)host_addr;
         h_addr_ptrs[1] = NULL;
-        (void) inet_aton(p, &host_addr);
         host.h_addr_list = h_addr_ptrs;
-        host.h_length = sizeof(u_int32_t);
-        host.h_addrtype = AF_INET;
+        host.h_length = len;
+        host.h_addrtype = af;
         while (*cp == ' ' || *cp == '\t')
                 cp++;
         host.h_name = cp;
         q = host.h_aliases = host_aliases;
-        cp = strpbrk(cp, " \t");
-        if (cp != NULL) 
+        if ((cp = strpbrk(cp, " \t")))
                 *cp++ = '\0';
         while (cp && *cp) {
                 if (*cp == ' ' || *cp == '\t') {
@@ -459,74 +854,61 @@ again:
                 }
                 if (q < &host_aliases[MAXALIASES - 1])
                         *q++ = cp;
-                cp = strpbrk(cp, " \t");
-                if (cp != NULL)
+                if ((cp = strpbrk(cp, " \t")))
                         *cp++ = '\0';
         }
         *q = NULL;
+        if (_resp->options & RES_USE_INET6) {
+                char *bp = hostbuf;
+                char *ep = hostbuf + sizeof hostbuf;
+
+                map_v4v6_hostent(&host, &bp, ep);
+        }
+        h_errno = NETDB_SUCCESS;
         return (&host);
 }
 
 struct hostent *
-_gethtbyname(name)
-        char *name;
+_gethtbyname2(const char *name, int af)
 {
-        register struct hostent *p;
-        register char **cp;
+        struct hostent *p;
+        char **cp;
         
         _sethtent(0);
-        while (p = _gethtent()) {
+        while ((p = _gethtent())) {
+                if (p->h_addrtype != af)
+                        continue;
                 if (strcasecmp(p->h_name, name) == 0)
                         break;
                 for (cp = p->h_aliases; *cp != 0; cp++)
                         if (strcasecmp(*cp, name) == 0)
                                 goto found;
         }
-found:
+ found:
         _endhtent();
-        if (p==NULL)
-                h_errno = HOST_NOT_FOUND;
         return (p);
 }
 
 struct hostent *
-_gethtbyaddr(addr, len, type)
-        const char *addr;
-        int len, type;
+_gethtbyaddr(const void *addr, socklen_t len, int af)
 {
-        register struct hostent *p;
+        struct hostent *p;
+
+        host.h_length = len;
+        host.h_addrtype = af;
 
         _sethtent(0);
-        while (p = _gethtent())
-                if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len))
+        while ((p = _gethtent()))
+                if (p->h_addrtype == af && p->h_length == len &&
+                    !bcmp(p->h_addr, addr, len))
                         break;
         _endhtent();
-        if (p==NULL)
-                h_errno = HOST_NOT_FOUND;
         return (p);
 }
 
-static int
-qcomp(a1, a2)
-        struct in_addr **a1, **a2;
-{
-        int pos1, pos2;
-
-        for (pos1 = 0; pos1 < _res.nsort; pos1++)
-                if (_res.sort_list[pos1].addr.s_addr ==
-                    ((*a1)->s_addr & _res.sort_list[pos1].mask))
-                        break;
-        for (pos2 = 0; pos2 < _res.nsort; pos2++)
-                if (_res.sort_list[pos2].addr.s_addr ==
-                    ((*a2)->s_addr & _res.sort_list[pos2].mask))
-                        break;
-        return pos1 - pos2;
-}
-
 #ifdef YP
 struct hostent *
-_yphostent(line)
-        char *line;
+_yphostent(char *line)
 {
         static struct in_addr host_addrs[MAXADDRS];
         char *p = line;
@@ -537,21 +919,21 @@ _yphostent(line)
 
         host.h_name = NULL;
         host.h_addr_list = h_addr_ptrs;
-        host.h_length = sizeof(u_int32_t);
+        host.h_length = INADDRSZ;
         host.h_addrtype = AF_INET;
         hap = h_addr_ptrs;
         buf = host_addrs;
         q = host.h_aliases = host_aliases;
 
 nextline:
+        /* check for host_addrs overflow */
+        if (buf >= &host_addrs[sizeof(host_addrs) / sizeof(host_addrs[0])])
+                goto done;
+
         more = 0;
         cp = strpbrk(p, " \t");
-        if (cp == NULL) {
-                if (host.h_name == NULL)
-                        return (NULL);
-                else
-                        goto done;
-        }
+        if (cp == NULL)
+                goto done;
         *cp++ = '\0';
 
         *hap++ = (char *)buf;
@@ -592,30 +974,28 @@ nextline:
                         *cp++ = '\0';
         }
 done:
+        if (host.h_name == NULL)
+                return (NULL);
         *q = NULL;
         *hap = NULL;
         return (&host);
 }
 
 struct hostent *
-_yp_gethtbyaddr(addr, len, type)
-        const char *addr;
-        int len, type;
+_yp_gethtbyaddr(const void *addr)
 {
-        struct hostent *hp = (struct hostent *)NULL;
+        struct hostent *hp = NULL;
+        const u_char *uaddr = (const u_char *)addr;
         static char *__ypcurrent;
         int __ypcurrentlen, r;
-        char name[sizeof("xxx.xxx.xxx.xxx") + 1];
+        char name[sizeof("xxx.xxx.xxx.xxx")];
         
         if (!__ypdomain) {
                 if (_yp_check(&__ypdomain) == 0)
                         return (hp);
         }
-        sprintf(name, "%u.%u.%u.%u",
-                ((unsigned)addr[0] & 0xff),
-                ((unsigned)addr[1] & 0xff),
-                ((unsigned)addr[2] & 0xff),
-                ((unsigned)addr[3] & 0xff));
+        snprintf(name, sizeof name, "%u.%u.%u.%u", (uaddr[0] & 0xff),
+            (uaddr[1] & 0xff), (uaddr[2] & 0xff), (uaddr[3] & 0xff));
         if (__ypcurrent)
                 free(__ypcurrent);
         __ypcurrent = NULL;
@@ -629,13 +1009,14 @@ _yp_gethtbyaddr(addr, len, type)
 }
 
 struct hostent *
-_yp_gethtbyname(name)
-        const char *name;
+_yp_gethtbyname(const char *name)
 {
         struct hostent *hp = (struct hostent *)NULL;
         static char *__ypcurrent;
         int __ypcurrentlen, r;
 
+        if (strlen(name) >= MAXHOSTNAMELEN)
+                return (NULL);
         if (!__ypdomain) {
                 if (_yp_check(&__ypdomain) == 0)
                         return (hp);
@@ -645,10 +1026,104 @@ _yp_gethtbyname(name)
         __ypcurrent = NULL;
         r = yp_match(__ypdomain, "hosts.byname", name,
                 strlen(name), &__ypcurrent, &__ypcurrentlen);
-        if (r==0)
+        if (r == 0)
                 hp = _yphostent(__ypcurrent);
-        if (hp==NULL)
+        if (hp == NULL)
                 h_errno = HOST_NOT_FOUND;
         return (hp);
 }
 #endif
+
+static void
+map_v4v6_address(const char *src, char *dst)
+{
+        u_char *p = (u_char *)dst;
+        char tmp[INADDRSZ];
+        int i;
+
+        /* Stash a temporary copy so our caller can update in place. */
+        bcopy(src, tmp, INADDRSZ);
+        /* Mark this ipv6 addr as a mapped ipv4. */
+        for (i = 0; i < 10; i++)
+                *p++ = 0x00;
+        *p++ = 0xff;
+        *p++ = 0xff;
+        /* Retrieve the saved copy and we're done. */
+        bcopy(tmp, (void*)p, INADDRSZ);
+}
+
+static void
+map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep)
+{
+        char **ap;
+
+        if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
+                return;
+        hp->h_addrtype = AF_INET6;
+        hp->h_length = IN6ADDRSZ;
+        for (ap = hp->h_addr_list; *ap; ap++) {
+                int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
+
+                if (ep - *bpp < (i + IN6ADDRSZ)) {
+                        /* Out of memory.  Truncate address list here.  XXX */
+                        *ap = NULL;
+                        return;
+                }
+                *bpp += i;
+                map_v4v6_address(*ap, *bpp);
+                *ap = *bpp;
+                *bpp += IN6ADDRSZ;
+        }
+}
+
+struct hostent *
+gethostent(void)
+{
+        host.h_addrtype = AF_UNSPEC;
+        host.h_length = 0;
+        return (_gethtent());
+}
+
+#ifdef RESOLVSORT
+static void
+addrsort(char **ap, int num)
+{
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+        int i, j;
+        char **p;
+        short aval[MAXADDRS];
+        int needsort = 0;
+
+        p = ap;
+        for (i = 0; i < num; i++, p++) {
+                for (j = 0 ; (unsigned)j < _resp->nsort; j++)
+                        if (_resp->sort_list[j].addr.s_addr == 
+                            (((struct in_addr *)(*p))->s_addr & 
+                            _resp->sort_list[j].mask))
+                                break;
+                aval[i] = j;
+                if (needsort == 0 && i > 0 && j < aval[i-1])
+                        needsort = i;
+        }
+        if (!needsort)
+                return;
+
+        while (needsort < num) {
+                for (j = needsort - 1; j >= 0; j--) {
+                        if (aval[j] > aval[j+1]) {
+                                char *hp;
+
+                                i = aval[j];
+                                aval[j] = aval[j+1];
+                                aval[j+1] = i;
+
+                                hp = ap[j];
+                                ap[j] = ap[j+1];
+                                ap[j+1] = hp;
+                        } else
+                                break;
+                }
+                needsort++;
+        }
+}
+#endif