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/* $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 <arpa/inet.h>
#include <arpa/nameser.h>
#include <assert.h>
#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <resolv.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include "hostent.h"
#include "resolv_private.h"
constexpr int MAXALIASES = 35;
constexpr int MAXADDRS = 35;
static void sethostent_r(FILE** hf) {
if (!*hf)
*hf = fopen(_PATH_HOSTS, "re");
else
rewind(*hf);
}
static void endhostent_r(FILE** hf) {
if (*hf) {
(void) fclose(*hf);
*hf = NULL;
}
}
// TODO: Consider returning a boolean result as files_getaddrinfo() does because the error code
// does not currently return to netd.
int _hf_gethtbyname2(const char* name, int af, getnamaddr* info) {
struct hostent *hp, hent;
char *buf, *ptr;
size_t len, num, i;
char* aliases[MAXALIASES];
char* addr_ptrs[MAXADDRS];
// TODO: Wrap the 'hf' into a RAII class or std::shared_ptr and modify the
// sethostent_r()/endhostent_r() to get rid of manually endhostent_r(&hf) everywhere.
FILE* hf = NULL;
sethostent_r(&hf);
if (hf == NULL) {
// TODO: Consider converting to a private extended EAI_* error code.
// Currently, the EAI_* value has no corresponding error code for invalid argument socket
// length. In order to not rely on errno, convert the original error code pair, EAI_SYSTEM
// and EINVAL, to EAI_FAIL.
return EAI_FAIL;
}
if ((ptr = buf = (char*) malloc(len = info->buflen)) == NULL) {
endhostent_r(&hf);
return EAI_MEMORY;
}
hent.h_name = NULL;
hent.h_addrtype = 0;
hent.h_length = 0;
size_t anum = 0;
for (num = 0; num < MAXADDRS; /**/) {
info->hp->h_addrtype = af;
info->hp->h_length = 0;
int he;
hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen, &he);
if (hp == NULL) {
if (he == NETDB_INTERNAL && errno == ENOSPC) {
goto nospc; // glibc compatibility.
}
break;
}
if (hp->h_name == nullptr) {
free(buf);
endhostent_r(&hf);
return EAI_FAIL;
}
const char* h_name = hp->h_name;
if (strcasecmp(h_name, name) != 0) {
char** cp;
for (cp = hp->h_aliases; *cp != NULL; cp++)
if (strcasecmp(*cp, name) == 0) break;
// NOTE: does not increment num
if (*cp == NULL) continue;
}
if (num == 0) {
hent.h_addrtype = hp->h_addrtype;
hent.h_length = hp->h_length;
HENT_SCOPY(hent.h_name, h_name, ptr, len);
for (anum = 0; hp->h_aliases[anum]; anum++) {
if (anum >= MAXALIASES) goto nospc;
const char* h_alias = hp->h_aliases[anum];
HENT_SCOPY(aliases[anum], h_alias, ptr, len);
}
ptr = align_ptr(ptr);
if ((size_t)(ptr - buf) >= info->buflen) goto nospc;
}
if (hp->h_addr_list[0] == nullptr) {
free(buf);
endhostent_r(&hf);
return EAI_FAIL;
}
const char* addr = hp->h_addr_list[0];
HENT_COPY(addr_ptrs[num], addr, hp->h_length, ptr, len);
num++;
}
endhostent_r(&hf);
if (num == 0) {
free(buf);
// TODO: Perhaps convert HOST_NOT_FOUND to EAI_NONAME instead.
// The original return error number is h_errno HOST_NOT_FOUND which was converted to
// EAI_NODATA.
return EAI_NODATA;
}
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);
// reserve space for mapping IPv4 address to IPv6 address in place
if (hp->h_addrtype == AF_INET) {
HENT_COPY(ptr, NAT64_PAD, sizeof(NAT64_PAD), ptr, len);
}
}
hp->h_addr_list[num] = NULL;
if (hent.h_name == nullptr) {
free(buf);
return EAI_FAIL;
}
// Curly brackets are required to avoid the "bypasses variable initialization" compile error.
{
const char* h_name = hent.h_name;
HENT_SCOPY(hp->h_name, 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 0;
nospc:
endhostent_r(&hf);
free(buf);
return EAI_MEMORY;
}
// TODO: Consider returning a boolean result as files_getaddrinfo() does because the error code
// does not currently return to netd.
int _hf_gethtbyaddr(const unsigned char* uaddr, int len, int af, getnamaddr* info) {
info->hp->h_length = len;
info->hp->h_addrtype = af;
FILE* hf = NULL;
sethostent_r(&hf);
if (hf == NULL) {
// TODO: Consider converting to a private extended EAI_* error code.
// Currently, the EAI_* value has no corresponding error code for invalid argument socket
// length. In order to not rely on errno, convert the original error code pair, EAI_SYSTEM
// and EINVAL, to EAI_FAIL.
return EAI_FAIL;
}
struct hostent* hp;
int he;
while ((hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen, &he)) != NULL) {
if (hp->h_addr_list[0] == nullptr) continue;
// Reassign it to a local variable to avoid -Wnullable-to-nonnull-conversion on calling
// memcmp.
const char* addr = hp->h_addr_list[0];
if (!memcmp(addr, uaddr, (size_t)hp->h_length)) break;
}
endhostent_r(&hf);
if (hp == NULL) {
if (errno == ENOSPC) return EAI_MEMORY; // glibc compatibility.
// TODO: Perhaps convert HOST_NOT_FOUND to EAI_NONAME instead.
// The original return error number is h_errno HOST_NOT_FOUND which was converted to
// EAI_NODATA.
return EAI_NODATA;
}
return 0;
}
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