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glibc/nss/nss_files/files-hosts.c
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/* Hosts file parser in nss_files module. | |
Copyright (C) 1996-2001, 2003, 2004, 2006, 2007 | |
Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
#include <assert.h> | |
#include <netinet/in.h> | |
#include <arpa/inet.h> | |
#include <arpa/nameser.h> | |
#include <netdb.h> | |
#include <resolv.h> | |
/* Get implementation for some internal functions. */ | |
#include "../resolv/mapv4v6addr.h" | |
#include "../resolv/res_hconf.h" | |
#define ENTNAME hostent | |
#define DATABASE "hosts" | |
#define NEED_H_ERRNO | |
#define EXTRA_ARGS , af, flags | |
#define EXTRA_ARGS_DECL , int af, int flags | |
#define ENTDATA hostent_data | |
struct hostent_data | |
{ | |
unsigned char host_addr[16]; /* IPv4 or IPv6 address. */ | |
char *h_addr_ptrs[2]; /* Points to that and null terminator. */ | |
}; | |
#define TRAILING_LIST_MEMBER h_aliases | |
#define TRAILING_LIST_SEPARATOR_P isspace | |
#include "files-parse.c" | |
LINE_PARSER | |
("#", | |
{ | |
char *addr; | |
STRING_FIELD (addr, isspace, 1); | |
/* Parse address. */ | |
if (inet_pton (af, addr, entdata->host_addr) <= 0) | |
{ | |
if (af == AF_INET6 && (flags & AI_V4MAPPED) != 0 | |
&& inet_pton (AF_INET, addr, entdata->host_addr) > 0) | |
map_v4v6_address ((char *) entdata->host_addr, | |
(char *) entdata->host_addr); | |
else if (af == AF_INET | |
&& inet_pton (AF_INET6, addr, entdata->host_addr) > 0) | |
{ | |
if (IN6_IS_ADDR_V4MAPPED (entdata->host_addr)) | |
memcpy (entdata->host_addr, entdata->host_addr + 12, INADDRSZ); | |
else if (IN6_IS_ADDR_LOOPBACK (entdata->host_addr)) | |
{ | |
in_addr_t localhost = htonl (INADDR_LOOPBACK); | |
memcpy (entdata->host_addr, &localhost, sizeof (localhost)); | |
} | |
else | |
/* Illegal address: ignore line. */ | |
return 0; | |
} | |
else | |
/* Illegal address: ignore line. */ | |
return 0; | |
} | |
/* We always return entries of the requested form. */ | |
result->h_addrtype = af; | |
result->h_length = af == AF_INET ? INADDRSZ : IN6ADDRSZ; | |
/* Store a pointer to the address in the expected form. */ | |
entdata->h_addr_ptrs[0] = (char *) entdata->host_addr; | |
entdata->h_addr_ptrs[1] = NULL; | |
result->h_addr_list = entdata->h_addr_ptrs; | |
STRING_FIELD (result->h_name, isspace, 1); | |
}) | |
#define HOST_DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \ | |
enum nss_status \ | |
_nss_files_get##name##_r (proto, \ | |
struct STRUCTURE *result, char *buffer, \ | |
size_t buflen, int *errnop H_ERRNO_PROTO) \ | |
{ \ | |
enum nss_status status; \ | |
\ | |
uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct hostent_data); \ | |
buffer += pad; \ | |
buflen = buflen > pad ? buflen - pad : 0; \ | |
\ | |
__libc_lock_lock (lock); \ | |
\ | |
/* Reset file pointer to beginning or open file. */ \ | |
status = internal_setent (keep_stream); \ | |
\ | |
if (status == NSS_STATUS_SUCCESS) \ | |
{ \ | |
/* Tell getent function that we have repositioned the file pointer. */ \ | |
last_use = getby; \ | |
\ | |
while ((status = internal_getent (result, buffer, buflen, errnop \ | |
H_ERRNO_ARG EXTRA_ARGS_VALUE)) \ | |
== NSS_STATUS_SUCCESS) \ | |
{ break_if_match } \ | |
\ | |
if (status == NSS_STATUS_SUCCESS \ | |
&& _res_hconf.flags & HCONF_FLAG_MULTI) \ | |
{ \ | |
/* We have to get all host entries from the file. */ \ | |
const size_t tmp_buflen = MIN (buflen, 4096); \ | |
char tmp_buffer[tmp_buflen] \ | |
__attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));\ | |
struct hostent tmp_result_buf; \ | |
int naddrs = 1; \ | |
int naliases = 0; \ | |
char *bufferend; \ | |
\ | |
while (result->h_aliases[naliases] != NULL) \ | |
++naliases; \ | |
\ | |
bufferend = (char *) &result->h_aliases[naliases + 1]; \ | |
\ | |
while ((status = internal_getent (&tmp_result_buf, tmp_buffer, \ | |
tmp_buflen, errnop H_ERRNO_ARG \ | |
EXTRA_ARGS_VALUE)) \ | |
== NSS_STATUS_SUCCESS) \ | |
{ \ | |
int matches = 1; \ | |
struct hostent *old_result = result; \ | |
result = &tmp_result_buf; \ | |
/* The following piece is a bit clumsy but we want to use the \ | |
`break_if_match' value. The optimizer should do its \ | |
job. */ \ | |
do \ | |
{ \ | |
break_if_match \ | |
result = old_result; \ | |
} \ | |
while ((matches = 0)); \ | |
\ | |
if (matches) \ | |
{ \ | |
/* We could be very clever and try to recycle a few bytes \ | |
in the buffer instead of generating new arrays. But \ | |
we are not doing this here since it's more work than \ | |
it's worth. Simply let the user provide a bit bigger \ | |
buffer. */ \ | |
char **new_h_addr_list; \ | |
char **new_h_aliases; \ | |
int newaliases = 0; \ | |
size_t newstrlen = 0; \ | |
int cnt; \ | |
\ | |
/* Count the new aliases and the length of the strings. */ \ | |
while (tmp_result_buf.h_aliases[newaliases] != NULL) \ | |
{ \ | |
char *cp = tmp_result_buf.h_aliases[newaliases]; \ | |
++newaliases; \ | |
newstrlen += strlen (cp) + 1; \ | |
} \ | |
/* If the real name is different add it also to the \ | |
aliases. This means that there is a duplication \ | |
in the alias list but this is really the users \ | |
problem. */ \ | |
if (strcmp (old_result->h_name, \ | |
tmp_result_buf.h_name) != 0) \ | |
{ \ | |
++newaliases; \ | |
newstrlen += strlen (tmp_result_buf.h_name) + 1; \ | |
} \ | |
\ | |
/* Make sure bufferend is aligned. */ \ | |
assert ((bufferend - (char *) 0) % sizeof (char *) == 0); \ | |
\ | |
/* Now we can check whether the buffer is large enough. \ | |
16 is the maximal size of the IP address. */ \ | |
if (bufferend + 16 + (naddrs + 2) * sizeof (char *) \ | |
+ roundup (newstrlen, sizeof (char *)) \ | |
+ (naliases + newaliases + 1) * sizeof (char *) \ | |
>= buffer + buflen) \ | |
{ \ | |
*errnop = ERANGE; \ | |
*herrnop = NETDB_INTERNAL; \ | |
status = NSS_STATUS_TRYAGAIN; \ | |
break; \ | |
} \ | |
\ | |
new_h_addr_list = \ | |
(char **) (bufferend \ | |
+ roundup (newstrlen, sizeof (char *)) \ | |
+ 16); \ | |
new_h_aliases = \ | |
(char **) ((char *) new_h_addr_list \ | |
+ (naddrs + 2) * sizeof (char *)); \ | |
\ | |
/* Copy the old data in the new arrays. */ \ | |
for (cnt = 0; cnt < naddrs; ++cnt) \ | |
new_h_addr_list[cnt] = old_result->h_addr_list[cnt]; \ | |
\ | |
for (cnt = 0; cnt < naliases; ++cnt) \ | |
new_h_aliases[cnt] = old_result->h_aliases[cnt]; \ | |
\ | |
/* Store the new strings. */ \ | |
cnt = 0; \ | |
while (tmp_result_buf.h_aliases[cnt] != NULL) \ | |
{ \ | |
new_h_aliases[naliases++] = bufferend; \ | |
bufferend = (__stpcpy (bufferend, \ | |
tmp_result_buf.h_aliases[cnt]) \ | |
+ 1); \ | |
++cnt; \ | |
} \ | |
\ | |
if (cnt < newaliases) \ | |
{ \ | |
new_h_aliases[naliases++] = bufferend; \ | |
bufferend = __stpcpy (bufferend, \ | |
tmp_result_buf.h_name) + 1; \ | |
} \ | |
\ | |
/* Final NULL pointer. */ \ | |
new_h_aliases[naliases] = NULL; \ | |
\ | |
/* Round up the buffer end address. */ \ | |
bufferend += (sizeof (char *) \ | |
- ((bufferend - (char *) 0) \ | |
% sizeof (char *))) % sizeof (char *); \ | |
\ | |
/* Now the new address. */ \ | |
new_h_addr_list[naddrs++] = \ | |
memcpy (bufferend, tmp_result_buf.h_addr, \ | |
tmp_result_buf.h_length); \ | |
\ | |
/* Also here a final NULL pointer. */ \ | |
new_h_addr_list[naddrs] = NULL; \ | |
\ | |
/* Store the new array pointers. */ \ | |
old_result->h_aliases = new_h_aliases; \ | |
old_result->h_addr_list = new_h_addr_list; \ | |
\ | |
/* Compute the new buffer end. */ \ | |
bufferend = (char *) &new_h_aliases[naliases + 1]; \ | |
assert (bufferend <= buffer + buflen); \ | |
\ | |
result = old_result; \ | |
} \ | |
} \ | |
\ | |
if (status != NSS_STATUS_TRYAGAIN) \ | |
status = NSS_STATUS_SUCCESS; \ | |
} \ | |
\ | |
\ | |
if (! keep_stream) \ | |
internal_endent (); \ | |
} \ | |
\ | |
__libc_lock_unlock (lock); \ | |
\ | |
return status; \ | |
} | |
#define EXTRA_ARGS_VALUE \ | |
, ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET), \ | |
((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0) | |
#include "files-XXX.c" | |
HOST_DB_LOOKUP (hostbyname, ,, | |
{ | |
LOOKUP_NAME_CASE (h_name, h_aliases) | |
}, const char *name) | |
#undef EXTRA_ARGS_VALUE | |
/* XXX Is using _res to determine whether we want to convert IPv4 addresses | |
to IPv6 addresses really the right thing to do? */ | |
#define EXTRA_ARGS_VALUE \ | |
, af, ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0) | |
HOST_DB_LOOKUP (hostbyname2, ,, | |
{ | |
LOOKUP_NAME_CASE (h_name, h_aliases) | |
}, const char *name, int af) | |
#undef EXTRA_ARGS_VALUE | |
/* We only need to consider IPv4 mapped addresses if the input to the | |
gethostbyaddr() function is an IPv6 address. */ | |
#define EXTRA_ARGS_VALUE \ | |
, af, (len == IN6ADDRSZ ? AI_V4MAPPED : 0) | |
DB_LOOKUP (hostbyaddr, ,, | |
{ | |
if (result->h_length == (int) len | |
&& ! memcmp (addr, result->h_addr_list[0], len)) | |
break; | |
}, const void *addr, socklen_t len, int af) |