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/* Copyright (C) 1997-2024 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, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <wctype.h>
#include <resolv/resolv-internal.h>
#include <resolv/resolv_context.h>
#include <netdb.h>
#include <arpa/inet.h>
#include "nsswitch.h"
#ifdef USE_NSCD
# include <nscd/nscd_proto.h>
#endif
int
__nss_hostname_digits_dots (const char *name, struct hostent *resbuf,
char **buffer, size_t *buffer_size,
size_t buflen, struct hostent **result,
enum nss_status *status, int af, int *h_errnop)
{
/* We have to test for the use of IPv6 which can only be done by
examining `_res'. */
struct resolv_context *ctx = __resolv_context_get ();
if (ctx == NULL)
{
if (h_errnop)
*h_errnop = NETDB_INTERNAL;
if (buffer_size == NULL)
*status = NSS_STATUS_TRYAGAIN;
else
*result = NULL;
return -1;
}
int ret = __nss_hostname_digits_dots_context
(ctx, name, resbuf, buffer, buffer_size, buflen,
result, status, af, h_errnop);
__resolv_context_put (ctx);
return ret;
}
int
__nss_hostname_digits_dots_context (struct resolv_context *ctx,
const char *name, struct hostent *resbuf,
char **buffer, size_t *buffer_size,
size_t buflen, struct hostent **result,
enum nss_status *status, int af, int *h_errnop)
{
int save;
/*
* disallow names consisting only of digits/dots, unless
* they end in a dot.
*/
if (isdigit (name[0]) || isxdigit (name[0]) || name[0] == ':')
{
const char *cp;
char *hostname;
typedef unsigned char host_addr_t[16];
host_addr_t *host_addr;
typedef char *host_addr_list_t[2];
host_addr_list_t *h_addr_ptrs;
char **h_alias_ptr;
size_t size_needed;
int addr_size;
switch (af)
{
case AF_INET:
addr_size = INADDRSZ;
break;
case AF_INET6:
addr_size = IN6ADDRSZ;
break;
default:
af = res_use_inet6 () ? AF_INET6 : AF_INET;
addr_size = af == AF_INET6 ? IN6ADDRSZ : INADDRSZ;
break;
}
size_needed = (sizeof (*host_addr)
+ sizeof (*h_addr_ptrs)
+ sizeof (*h_alias_ptr) + strlen (name) + 1);
if (buffer_size == NULL)
{
if (buflen < size_needed)
{
*status = NSS_STATUS_TRYAGAIN;
if (h_errnop != NULL)
*h_errnop = NETDB_INTERNAL;
__set_errno (ERANGE);
goto done;
}
}
else if (buffer_size != NULL && *buffer_size < size_needed)
{
char *new_buf;
*buffer_size = size_needed;
new_buf = (char *) realloc (*buffer, *buffer_size);
if (new_buf == NULL)
{
save = errno;
free (*buffer);
*buffer = NULL;
*buffer_size = 0;
__set_errno (save);
if (h_errnop != NULL)
*h_errnop = NETDB_INTERNAL;
*result = NULL;
goto done;
}
*buffer = new_buf;
}
memset (*buffer, '\0', size_needed);
host_addr = (host_addr_t *) *buffer;
h_addr_ptrs = (host_addr_list_t *)
((char *) host_addr + sizeof (*host_addr));
h_alias_ptr = (char **) ((char *) h_addr_ptrs + sizeof (*h_addr_ptrs));
hostname = (char *) h_alias_ptr + sizeof (*h_alias_ptr);
if (isdigit (name[0]))
{
for (cp = name;; ++cp)
{
if (*cp == '\0')
{
int ok;
if (*--cp == '.')
break;
/* All-numeric, no dot at the end. Fake up a hostent as if
we'd actually done a lookup. What if someone types
255.255.255.255? The test below will succeed
spuriously... ??? */
if (af == AF_INET)
ok = __inet_aton_exact (name, (struct in_addr *) host_addr);
else
{
assert (af == AF_INET6);
ok = inet_pton (af, name, host_addr) > 0;
}
if (! ok)
{
*h_errnop = HOST_NOT_FOUND;
if (buffer_size == NULL)
*status = NSS_STATUS_NOTFOUND;
else
*result = NULL;
goto done;
}
resbuf->h_name = strcpy (hostname, name);
h_alias_ptr[0] = NULL;
resbuf->h_aliases = h_alias_ptr;
(*h_addr_ptrs)[0] = (char *) host_addr;
(*h_addr_ptrs)[1] = NULL;
resbuf->h_addr_list = *h_addr_ptrs;
if (af == AF_INET && res_use_inet6 ())
{
/* We need to change the IP v4 address into the
IP v6 address. */
char tmp[INADDRSZ];
char *p = (char *) host_addr;
int i;
/* Save a copy of the IP v4 address. */
memcpy (tmp, host_addr, INADDRSZ);
/* Mark this ipv6 addr as a mapped ipv4. */
for (i = 0; i < 10; i++)
*p++ = 0x00;
*p++ = 0xff;
*p++ = 0xff;
/* Copy the IP v4 address. */
memcpy (p, tmp, INADDRSZ);
resbuf->h_addrtype = AF_INET6;
resbuf->h_length = IN6ADDRSZ;
}
else
{
resbuf->h_addrtype = af;
resbuf->h_length = addr_size;
}
if (h_errnop != NULL)
*h_errnop = NETDB_SUCCESS;
if (buffer_size == NULL)
*status = NSS_STATUS_SUCCESS;
else
*result = resbuf;
goto done;
}
if (!isdigit (*cp) && *cp != '.')
break;
}
}
if ((isxdigit (name[0]) && strchr (name, ':') != NULL) || name[0] == ':')
{
switch (af)
{
default:
af = res_use_inet6 () ? AF_INET6 : AF_INET;
if (af == AF_INET6)
{
addr_size = IN6ADDRSZ;
break;
}
/* FALLTHROUGH */
case AF_INET:
/* This is not possible. We cannot represent an IPv6 address
in an `struct in_addr' variable. */
*h_errnop = HOST_NOT_FOUND;
if (buffer_size == NULL)
*status = NSS_STATUS_NOTFOUND;
else
*result = NULL;
goto done;
case AF_INET6:
addr_size = IN6ADDRSZ;
break;
}
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_INET6, name, host_addr) <= 0)
{
*h_errnop = HOST_NOT_FOUND;
if (buffer_size == NULL)
*status = NSS_STATUS_NOTFOUND;
else
*result = NULL;
goto done;
}
resbuf->h_name = strcpy (hostname, name);
h_alias_ptr[0] = NULL;
resbuf->h_aliases = h_alias_ptr;
(*h_addr_ptrs)[0] = (char *) host_addr;
(*h_addr_ptrs)[1] = (char *) 0;
resbuf->h_addr_list = *h_addr_ptrs;
resbuf->h_addrtype = AF_INET6;
resbuf->h_length = addr_size;
*h_errnop = NETDB_SUCCESS;
if (buffer_size == NULL)
*status = NSS_STATUS_SUCCESS;
else
*result = resbuf;
goto done;
}
if (!isxdigit (*cp) && *cp != ':' && *cp != '.')
break;
}
}
}
return 0;
done:
return 1;
}
libc_hidden_def (__nss_hostname_digits_dots)
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