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/* Copyright (C) 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
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 <errno.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <not-cancel.h>
#include "nscd-client.h"
#include "nscd_proto.h"
/* Define in nscd_gethst_r.c. */
extern int __nss_not_use_nscd_hosts;
/* We use the mapping from nscd_gethst. */
libc_locked_map_ptr (extern, __hst_map_handle);
int
__nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop)
{
size_t keylen = strlen (key) + 1;
int gc_cycle;
/* If the mapping is available, try to search there instead of
communicating with the nscd. */
struct mapped_database *mapped;
mapped = __nscd_get_map_ref (GETFDHST, "hosts", &__hst_map_handle,
&gc_cycle);
retry:;
const ai_response_header *ai_resp = NULL;
struct nscd_ai_result *resultbuf = NULL;
const char *recend = (const char *) ~UINTMAX_C (0);
char *respdata = NULL;
int retval = -1;
int sock = -1;
if (mapped != NO_MAPPING)
{
const struct datahead *found = __nscd_cache_search (GETAI, key, keylen,
mapped);
if (found != NULL)
{
ai_resp = &found->data[0].aidata;
respdata = (char *) (ai_resp + 1);
recend = (const char *) found->data + found->recsize;
}
}
/* If we do not have the cache mapped, try to get the data over the
socket. */
ai_response_header ai_resp_mem;
if (ai_resp == NULL)
{
sock = __nscd_open_socket (key, keylen, GETAI, &ai_resp_mem,
sizeof (ai_resp_mem));
if (sock == -1)
{
/* nscd not running or wrong version or hosts caching disabled. */
__nss_not_use_nscd_hosts = 1;
goto out;
}
ai_resp = &ai_resp_mem;
}
if (ai_resp->found == 1)
{
size_t datalen = ai_resp->naddrs + ai_resp->addrslen + ai_resp->canonlen;
/* This check is really only affects the case where the data
comes from the mapped cache. */
if ((char *) (ai_resp + 1) + datalen > recend)
{
assert (sock == -1);
goto out;
}
/* Create result. */
resultbuf = (struct nscd_ai_result *) malloc (sizeof (*resultbuf)
+ datalen);
if (resultbuf == NULL)
{
*h_errnop = NETDB_INTERNAL;
goto out_close;
}
/* Set up the data structure, including pointers. */
resultbuf->naddrs = ai_resp->naddrs;
resultbuf->addrs = (char *) (resultbuf + 1);
resultbuf->family = (uint8_t *) (resultbuf->addrs + ai_resp->addrslen);
if (ai_resp->canonlen != 0)
resultbuf->canon = (char *) (resultbuf->family + resultbuf->naddrs);
else
resultbuf->canon = NULL;
if (respdata == NULL)
{
/* Read the data from the socket. */
if ((size_t) TEMP_FAILURE_RETRY (__read (sock, resultbuf + 1,
datalen)) == datalen)
{
retval = 0;
*result = resultbuf;
}
else
{
free (resultbuf);
*h_errnop = NETDB_INTERNAL;
}
}
else
{
/* Copy the data in the block. */
memcpy (resultbuf + 1, respdata, datalen);
/* Try to detect corrupt databases. */
if (resultbuf->canon != NULL
&& resultbuf->canon[ai_resp->canonlen - 1] != '\0')
/* We cannot use the database. */
{
free (resultbuf);
goto out_close;
}
retval = 0;
*result = resultbuf;
}
}
else
{
/* Store the error number. */
*h_errnop = ai_resp->error;
/* The `errno' to some value != ERANGE. */
__set_errno (ENOENT);
/* Even though we have not found anything, the result is zero. */
retval = 0;
}
out_close:
if (sock != -1)
close_not_cancel_no_status (sock);
out:
if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1)
{
/* When we come here this means there has been a GC cycle while we
were looking for the data. This means the data might have been
inconsistent. Retry if possible. */
if ((gc_cycle & 1) != 0)
{
/* nscd is just running gc now. Disable using the mapping. */
__nscd_unmap (mapped);
mapped = NO_MAPPING;
}
*result = NULL;
free (resultbuf);
goto retry;
}
return retval;
}
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