Sync with upstream for gethnamaddr.c.

Bug: 18566967
Change-Id: I37e7410226b49eec67614e20b2c1d5e3e47817a5
diff --git a/libc/dns/net/sethostent.c b/libc/dns/net/sethostent.c
new file mode 100644
index 0000000..f501c8b
--- /dev/null
+++ b/libc/dns/net/sethostent.c
@@ -0,0 +1,266 @@
+/*	$NetBSD: sethostent.c,v 1.20 2014/03/17 13:24:23 christos Exp $	*/
+
+/*
+ * Copyright (c) 1985, 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.
+ */
+
+#include <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+#if 0
+static char sccsid[] = "@(#)sethostent.c	8.1 (Berkeley) 6/4/93";
+static char rcsid[] = "Id: sethostent.c,v 8.5 1996/09/28 06:51:07 vixie Exp ";
+#else
+__RCSID("$NetBSD: sethostent.c,v 1.20 2014/03/17 13:24:23 christos Exp $");
+#endif
+#endif /* LIBC_SCCS and not lint */
+
+#include "namespace.h"
+#include <sys/param.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <arpa/inet.h>
+#include <assert.h>
+#include <string.h>
+#include <nsswitch.h>
+#include <netdb.h>
+#include <resolv.h>
+#include <errno.h>
+#include <stdlib.h>
+
+#include "hostent.h"
+#include "resolv_private.h"
+
+#define ALIGNBYTES (sizeof(uintptr_t) - 1)
+#define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) &~ ALIGNBYTES)
+
+#ifndef _REENTRANT
+void	res_close(void);
+#endif
+
+static struct hostent *_hf_gethtbyname2(const char *, int, struct getnamaddr *);
+
+static const char *_h_hosts = _PATH_HOSTS;
+
+void
+sethostent_r(FILE **hf)
+{
+	if (!*hf)
+		*hf = fopen(_h_hosts, "re");
+	else
+		rewind(*hf);
+}
+
+void
+endhostent_r(FILE **hf)
+{
+	if (*hf) {
+		(void)fclose(*hf);
+		*hf = NULL;
+	}
+}
+
+/*ARGSUSED*/
+int
+_hf_gethtbyname(void *rv, void *cb_data, va_list ap)
+{
+	struct hostent *hp;
+	const char *name;
+	int af;
+	struct getnamaddr *info = rv;
+
+	_DIAGASSERT(rv != NULL);
+
+	name = va_arg(ap, char *);
+	/* NOSTRICT skip string len */(void)va_arg(ap, int);
+	af = va_arg(ap, int);
+
+#if 0
+	{
+		res_state res = __res_get_state();
+		if (res == NULL)
+			return NS_NOTFOUND;
+		if (res->options & RES_USE_INET6)
+			hp = _hf_gethtbyname2(name, AF_INET6, info);
+		else
+			hp = NULL;
+		if (hp == NULL)
+			hp = _hf_gethtbyname2(name, AF_INET, info);
+		__res_put_state(res);
+	}
+#else
+	hp = _hf_gethtbyname2(name, af, info);
+#endif
+	if (hp == NULL) {
+		*info->he = HOST_NOT_FOUND;
+		return NS_NOTFOUND;
+	}
+	return NS_SUCCESS;
+}
+
+static struct hostent *
+_hf_gethtbyname2(const char *name, int af, struct getnamaddr *info)
+{
+	struct hostent *hp, hent;
+	char *buf, *ptr;
+	size_t len, anum, num, i;
+	FILE *hf;
+	char *aliases[MAXALIASES];
+	char *addr_ptrs[MAXADDRS];
+
+	_DIAGASSERT(name != NULL);
+
+	hf = NULL;
+	sethostent_r(&hf);
+	if (hf == NULL) {
+		errno = EINVAL;
+		*info->he = NETDB_INTERNAL;
+		return NULL;
+	}
+
+	if ((ptr = buf = malloc(len = info->buflen)) == NULL) {
+		endhostent_r(&hf);
+		*info->he = NETDB_INTERNAL;
+		return NULL;
+	}
+
+	anum = 0;		/* XXX: gcc */
+	hent.h_name = NULL;	/* XXX: gcc */
+	hent.h_addrtype = 0;	/* XXX: gcc */
+	hent.h_length = 0;	/* XXX: gcc */
+
+	for (num = 0; num < MAXADDRS;) {
+		info->hp->h_addrtype = af;
+		info->hp->h_length = 0;
+
+		hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen,
+		    info->he);
+		if (hp == NULL)
+			break;
+
+		if (strcasecmp(hp->h_name, name) != 0) {
+			char **cp;
+			for (cp = hp->h_aliases; *cp != NULL; cp++)
+				if (strcasecmp(*cp, name) == 0)
+					break;
+			if (*cp == NULL) continue;
+		}
+
+		if (num == 0) {
+			hent.h_addrtype = af = hp->h_addrtype;
+			hent.h_length = hp->h_length;
+
+			HENT_SCOPY(hent.h_name, hp->h_name, ptr, len);
+			for (anum = 0; hp->h_aliases[anum]; anum++) {
+				if (anum >= MAXALIASES)
+					goto nospc;
+				HENT_SCOPY(aliases[anum], hp->h_aliases[anum],
+				    ptr, len);
+			}
+			ptr = (void *)ALIGN(ptr);
+			if ((size_t)(ptr - buf) >= info->buflen)
+				goto nospc;
+		}
+
+		if (num >= MAXADDRS)
+			goto nospc;
+		HENT_COPY(addr_ptrs[num], hp->h_addr_list[0], hp->h_length, ptr,
+		    len);
+		num++;
+	}
+	endhostent_r(&hf);
+
+	if (num == 0) {
+		*info->he = HOST_NOT_FOUND;
+		free(buf);
+		return NULL;
+	}
+
+	hp = info->hp;
+	ptr = info->buf;
+	len = info->buflen;
+
+	hp->h_addrtype = hent.h_addrtype;
+	hp->h_length = hent.h_length;
+
+	HENT_ARRAY(hp->h_aliases, anum, ptr, len);
+	HENT_ARRAY(hp->h_addr_list, num, ptr, len);
+
+	for (i = 0; i < num; i++)
+		HENT_COPY(hp->h_addr_list[i], addr_ptrs[i], hp->h_length, ptr,
+		    len);
+	hp->h_addr_list[num] = NULL;
+
+	HENT_SCOPY(hp->h_name, hent.h_name, ptr, len);
+
+	for (i = 0; i < anum; i++)
+		HENT_SCOPY(hp->h_aliases[i], aliases[i], ptr, len);
+	hp->h_aliases[anum] = NULL;
+
+	free(buf);
+	return hp;
+nospc:
+	endhostent_r(&hf);
+	*info->he = NETDB_INTERNAL;
+	free(buf);
+	errno = ENOSPC;
+	return NULL;
+}
+
+/*ARGSUSED*/
+int
+_hf_gethtbyaddr(void *rv, void *cb_data, va_list ap)
+{
+	struct hostent *hp;
+	const unsigned char *addr;
+	struct getnamaddr *info = rv;
+	FILE *hf;
+
+	_DIAGASSERT(rv != NULL);
+
+	addr = va_arg(ap, unsigned char *);
+	info->hp->h_length = va_arg(ap, int);
+	info->hp->h_addrtype = va_arg(ap, int);
+
+	hf = NULL;
+	sethostent_r(&hf);
+	if (hf == NULL) {
+		*info->he = NETDB_INTERNAL;
+		return NS_UNAVAIL;
+	}
+	while ((hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen,
+	    info->he)) != NULL)
+		if (!memcmp(hp->h_addr_list[0], addr, (size_t)hp->h_length))
+			break;
+	endhostent_r(&hf);
+
+	if (hp == NULL) {
+		*info->he = HOST_NOT_FOUND;
+		return NS_NOTFOUND;
+	}
+	return NS_SUCCESS;
+}