589 lines
16 KiB
C
589 lines
16 KiB
C
/* Cache handling for host lookup.
|
|
Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
|
|
|
|
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 <error.h>
|
|
#include <netdb.h>
|
|
#include <stdbool.h>
|
|
#include <stddef.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
#include <libintl.h>
|
|
#include <arpa/inet.h>
|
|
#include <arpa/nameser.h>
|
|
#include <stackinfo.h>
|
|
|
|
#include "nscd.h"
|
|
#include "dbg_log.h"
|
|
|
|
|
|
/* This is the standard reply in case the service is disabled. */
|
|
static const hst_response_header disabled =
|
|
{
|
|
version: NSCD_VERSION,
|
|
found: -1,
|
|
h_name_len: 0,
|
|
h_aliases_cnt: 0,
|
|
h_addrtype: -1,
|
|
h_length: -1,
|
|
h_addr_list_cnt: 0,
|
|
error: NETDB_INTERNAL
|
|
};
|
|
|
|
/* This is the struct describing how to write this record. */
|
|
const struct iovec hst_iov_disabled =
|
|
{
|
|
iov_base: (void *) &disabled,
|
|
iov_len: sizeof (disabled)
|
|
};
|
|
|
|
|
|
/* This is the standard reply in case we haven't found the dataset. */
|
|
static const hst_response_header notfound =
|
|
{
|
|
version: NSCD_VERSION,
|
|
found: 0,
|
|
h_name_len: 0,
|
|
h_aliases_cnt: 0,
|
|
h_addrtype: -1,
|
|
h_length: -1,
|
|
h_addr_list_cnt: 0,
|
|
error: HOST_NOT_FOUND
|
|
};
|
|
|
|
/* This is the struct describing how to write this record. */
|
|
static const struct iovec iov_notfound =
|
|
{
|
|
iov_base: (void *) ¬found,
|
|
iov_len: sizeof (notfound)
|
|
};
|
|
|
|
|
|
struct hostdata
|
|
{
|
|
hst_response_header resp;
|
|
char strdata[0];
|
|
};
|
|
|
|
|
|
static void
|
|
cache_addhst (struct database *db, int fd, request_header *req, void *key,
|
|
struct hostent *hst, uid_t owner)
|
|
{
|
|
ssize_t total;
|
|
ssize_t written;
|
|
time_t t = time (NULL);
|
|
|
|
if (hst == NULL)
|
|
{
|
|
/* We have no data. This means we send the standard reply for this
|
|
case. */
|
|
void *copy;
|
|
|
|
total = sizeof (notfound);
|
|
|
|
written = writev (fd, &iov_notfound, 1);
|
|
|
|
copy = malloc (req->key_len);
|
|
if (copy == NULL)
|
|
error (EXIT_FAILURE, errno, _("while allocating key copy"));
|
|
memcpy (copy, key, req->key_len);
|
|
|
|
/* Compute the timeout time. */
|
|
t += db->negtimeout;
|
|
|
|
/* Now get the lock to safely insert the records. */
|
|
pthread_rwlock_rdlock (&db->lock);
|
|
|
|
cache_add (req->type, copy, req->key_len, ¬found,
|
|
sizeof (notfound), (void *) -1, 0, t, db, owner);
|
|
|
|
pthread_rwlock_unlock (&db->lock);
|
|
}
|
|
else
|
|
{
|
|
/* Determine the I/O structure. */
|
|
struct hostdata *data;
|
|
size_t h_name_len = strlen (hst->h_name) + 1;
|
|
size_t h_aliases_cnt;
|
|
uint32_t *h_aliases_len;
|
|
size_t h_addr_list_cnt;
|
|
int addr_list_type;
|
|
char *addresses;
|
|
char *aliases;
|
|
char *key_copy = NULL;
|
|
char *cp;
|
|
size_t cnt;
|
|
|
|
/* Determine the number of aliases. */
|
|
h_aliases_cnt = 0;
|
|
for (cnt = 0; hst->h_aliases[cnt] != NULL; ++cnt)
|
|
++h_aliases_cnt;
|
|
/* Determine the length of all aliases. */
|
|
h_aliases_len = (uint32_t *) alloca (h_aliases_cnt * sizeof (uint32_t));
|
|
total = 0;
|
|
for (cnt = 0; cnt < h_aliases_cnt; ++cnt)
|
|
{
|
|
h_aliases_len[cnt] = strlen (hst->h_aliases[cnt]) + 1;
|
|
total += h_aliases_len[cnt];
|
|
}
|
|
|
|
/* Determine the number of addresses. */
|
|
h_addr_list_cnt = 0;
|
|
for (cnt = 0; hst->h_addr_list[cnt]; ++cnt)
|
|
++h_addr_list_cnt;
|
|
|
|
/* We allocate all data in one memory block: the iov vector,
|
|
the response header and the dataset itself. */
|
|
total += (sizeof (struct hostdata)
|
|
+ h_name_len
|
|
+ h_aliases_cnt * sizeof (uint32_t)
|
|
+ h_addr_list_cnt * hst->h_length);
|
|
|
|
data = (struct hostdata *) malloc (total + req->key_len);
|
|
if (data == NULL)
|
|
/* There is no reason to go on. */
|
|
error (EXIT_FAILURE, errno, _("while allocating cache entry"));
|
|
|
|
data->resp.found = 1;
|
|
data->resp.h_name_len = h_name_len;
|
|
data->resp.h_aliases_cnt = h_aliases_cnt;
|
|
data->resp.h_addrtype = hst->h_addrtype;
|
|
data->resp.h_length = hst->h_length;
|
|
data->resp.h_addr_list_cnt = h_addr_list_cnt;
|
|
data->resp.error = NETDB_SUCCESS;
|
|
|
|
cp = data->strdata;
|
|
|
|
cp = mempcpy (cp, hst->h_name, h_name_len);
|
|
cp = mempcpy (cp, h_aliases_len, h_aliases_cnt * sizeof (uint32_t));
|
|
|
|
/* The normal addresses first. */
|
|
addresses = cp;
|
|
for (cnt = 0; cnt < h_addr_list_cnt; ++cnt)
|
|
cp = mempcpy (cp, hst->h_addr_list[cnt], hst->h_length);
|
|
|
|
/* Then the aliases. */
|
|
aliases = cp;
|
|
for (cnt = 0; cnt < h_aliases_cnt; ++cnt)
|
|
cp = mempcpy (cp, hst->h_aliases[cnt], h_aliases_len[cnt]);
|
|
|
|
assert (cp == data->strdata + total - sizeof (hst_response_header));
|
|
|
|
/* If we are adding a GETHOSTBYNAME{,v6} entry we must be prepared
|
|
that the answer we get from the NSS does not contain the key
|
|
itself. This is the case if the resolver is used and the name
|
|
is extended by the domainnames from /etc/resolv.conf. Therefore
|
|
we explicitly add the name here. */
|
|
if (req->type == GETHOSTBYNAME || req->type == GETHOSTBYNAMEv6)
|
|
key_copy = memcpy (cp, key, req->key_len);
|
|
|
|
/* We write the dataset before inserting it to the database
|
|
since while inserting this thread might block and so would
|
|
unnecessarily let the receiver wait. */
|
|
written = TEMP_FAILURE_RETRY (write (fd, data, total));
|
|
|
|
addr_list_type = (hst->h_length == NS_INADDRSZ
|
|
? GETHOSTBYADDR : GETHOSTBYADDRv6);
|
|
|
|
/* Compute the timeout time. */
|
|
t += db->postimeout;
|
|
|
|
/* Now get the lock to safely insert the records. */
|
|
pthread_rwlock_rdlock (&db->lock);
|
|
|
|
/* First add all the aliases. If the record contains more than
|
|
one IP address (used for load balancing etc) don't cache the
|
|
entry. This is something the current cache handling cannot
|
|
handle and it is more than questionable whether it is
|
|
worthwhile complicating the cache handling just for handling
|
|
such a special case. */
|
|
if (hst->h_addr_list[1] == NULL)
|
|
for (cnt = 0; cnt < h_aliases_cnt; ++cnt)
|
|
{
|
|
if (addr_list_type == GETHOSTBYADDR)
|
|
cache_add (GETHOSTBYNAME, aliases, h_aliases_len[cnt], data,
|
|
total, data, 0, t, db, owner);
|
|
|
|
cache_add (GETHOSTBYNAMEv6, aliases, h_aliases_len[cnt], data,
|
|
total, data, 0, t, db, owner);
|
|
|
|
aliases += h_aliases_len[cnt];
|
|
}
|
|
|
|
/* Next the normal addresses. */
|
|
for (cnt = 0; cnt < h_addr_list_cnt; ++cnt)
|
|
{
|
|
cache_add (addr_list_type, addresses, hst->h_length, data, total,
|
|
data, 0, t, db, owner);
|
|
addresses += hst->h_length;
|
|
}
|
|
|
|
/* If necessary the IPv6 addresses. */
|
|
if (addr_list_type == GETHOSTBYADDR)
|
|
for (cnt = 0; cnt < h_addr_list_cnt; ++cnt)
|
|
{
|
|
cache_add (GETHOSTBYADDRv6, addresses, IN6ADDRSZ, data, total,
|
|
data, 0, t, db, owner);
|
|
addresses += IN6ADDRSZ;
|
|
}
|
|
|
|
/* Avoid adding names if more than one address is available. See
|
|
above for more info. */
|
|
if (hst->h_addr_list[1] == NULL)
|
|
{
|
|
/* If necessary add the key for this request. */
|
|
if (req->type == GETHOSTBYNAME || req->type == GETHOSTBYNAMEv6)
|
|
{
|
|
if (addr_list_type == GETHOSTBYADDR)
|
|
cache_add (GETHOSTBYNAME, key_copy, req->key_len, data, total,
|
|
data, 0, t, db, owner);
|
|
cache_add (GETHOSTBYNAMEv6, key_copy, req->key_len, data,
|
|
total, data, 0, t, db, owner);
|
|
}
|
|
|
|
/* And finally the name. We mark this as the last entry. */
|
|
if (addr_list_type == GETHOSTBYADDR)
|
|
cache_add (GETHOSTBYNAME, data->strdata, h_name_len, data, total,
|
|
data, 0, t, db, owner);
|
|
cache_add (GETHOSTBYNAMEv6, data->strdata, h_name_len, data,
|
|
total, data, 1, t, db, owner);
|
|
}
|
|
|
|
pthread_rwlock_unlock (&db->lock);
|
|
}
|
|
|
|
if (__builtin_expect (written != total, 0) && debug_level > 0)
|
|
{
|
|
char buf[256];
|
|
dbg_log (_("short write in %s: %s"), __FUNCTION__,
|
|
strerror_r (errno, buf, sizeof (buf)));
|
|
}
|
|
}
|
|
|
|
|
|
void
|
|
addhstbyname (struct database *db, int fd, request_header *req,
|
|
void *key, uid_t uid)
|
|
{
|
|
/* Search for the entry matching the key. Please note that we don't
|
|
look again in the table whether the dataset is now available. We
|
|
simply insert it. It does not matter if it is in there twice. The
|
|
pruning function only will look at the timestamp. */
|
|
int buflen = 1024;
|
|
char *buffer = (char *) alloca (buflen);
|
|
struct hostent resultbuf;
|
|
struct hostent *hst;
|
|
uid_t oldeuid = 0;
|
|
bool use_malloc = false;
|
|
|
|
if (__builtin_expect (debug_level > 0, 0))
|
|
dbg_log (_("Haven't found \"%s\" in hosts cache!"), (char *) key);
|
|
|
|
if (secure[hstdb])
|
|
{
|
|
oldeuid = geteuid ();
|
|
seteuid (uid);
|
|
}
|
|
|
|
while (__gethostbyname2_r (key, AF_INET, &resultbuf, buffer, buflen,
|
|
&hst, &h_errno) != 0
|
|
&& h_errno == NETDB_INTERNAL
|
|
&& errno == ERANGE)
|
|
{
|
|
char *old_buffer = buffer;
|
|
errno = 0;
|
|
buflen += 1024;
|
|
|
|
if (__builtin_expect (buflen > 32768, 0))
|
|
{
|
|
buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
|
|
if (buffer == NULL)
|
|
{
|
|
/* We ran out of memory. We cannot do anything but
|
|
sending a negative response. In reality this should
|
|
never happen. */
|
|
hst = NULL;
|
|
buffer = old_buffer;
|
|
break;
|
|
}
|
|
use_malloc = true;
|
|
}
|
|
else
|
|
{
|
|
buffer = (char *) alloca (buflen);
|
|
#if _STACK_GROWS_DOWN
|
|
if (buffer + buflen == old_buffer)
|
|
buflen = 2 * buflen - 1024;
|
|
#elif _STACK_GROWS_UP
|
|
if (old_buffer + buflen - 1024 == buffer)
|
|
{
|
|
buffer = old_buffer;
|
|
buflen = 2 * buflen - 1024;
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
if (secure[hstdb])
|
|
seteuid (oldeuid);
|
|
|
|
cache_addhst (db, fd, req, key, hst, uid);
|
|
|
|
if (use_malloc)
|
|
free (buffer);
|
|
}
|
|
|
|
|
|
void
|
|
addhstbyaddr (struct database *db, int fd, request_header *req,
|
|
void *key, uid_t uid)
|
|
{
|
|
/* Search for the entry matching the key. Please note that we don't
|
|
look again in the table whether the dataset is now available. We
|
|
simply insert it. It does not matter if it is in there twice. The
|
|
pruning function only will look at the timestamp. */
|
|
int buflen = 1024;
|
|
char *buffer = (char *) alloca (buflen);
|
|
struct hostent resultbuf;
|
|
struct hostent *hst;
|
|
uid_t oldeuid = 0;
|
|
bool use_malloc = false;
|
|
|
|
if (__builtin_expect (debug_level > 0, 0))
|
|
{
|
|
char buf[INET_ADDRSTRLEN];
|
|
dbg_log (_("Haven't found \"%s\" in hosts cache!"),
|
|
inet_ntop (AF_INET, key, buf, sizeof (buf)));
|
|
}
|
|
|
|
if (secure[hstdb])
|
|
{
|
|
oldeuid = geteuid ();
|
|
seteuid (uid);
|
|
}
|
|
|
|
while (__gethostbyaddr_r (key, NS_INADDRSZ, AF_INET, &resultbuf, buffer,
|
|
buflen, &hst, &h_errno) != 0
|
|
&& h_errno == NETDB_INTERNAL
|
|
&& errno == ERANGE)
|
|
{
|
|
char *old_buffer = buffer;
|
|
errno = 0;
|
|
buflen += 1024;
|
|
|
|
if (__builtin_expect (buflen > 32768, 0))
|
|
{
|
|
buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
|
|
if (buffer == NULL)
|
|
{
|
|
/* We ran out of memory. We cannot do anything but
|
|
sending a negative response. In reality this should
|
|
never happen. */
|
|
hst = NULL;
|
|
buffer = old_buffer;
|
|
break;
|
|
}
|
|
use_malloc = true;
|
|
}
|
|
else
|
|
{
|
|
buffer = (char *) alloca (buflen);
|
|
#if _STACK_GROWS_DOWN
|
|
if (buffer + buflen == old_buffer)
|
|
buflen = 2 * buflen - 1024;
|
|
#elif _STACK_GROWS_UP
|
|
if (old_buffer + buflen - 1024 == buffer)
|
|
{
|
|
buffer = old_buffer;
|
|
buflen = 2 * buflen - 1024;
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
if (secure[hstdb])
|
|
seteuid (oldeuid);
|
|
|
|
cache_addhst (db, fd, req, key, hst, uid);
|
|
|
|
if (use_malloc)
|
|
free (buffer);
|
|
}
|
|
|
|
|
|
void
|
|
addhstbynamev6 (struct database *db, int fd, request_header *req,
|
|
void *key, uid_t uid)
|
|
{
|
|
/* Search for the entry matching the key. Please note that we don't
|
|
look again in the table whether the dataset is now available. We
|
|
simply insert it. It does not matter if it is in there twice. The
|
|
pruning function only will look at the timestamp. */
|
|
int buflen = 1024;
|
|
char *buffer = (char *) alloca (buflen);
|
|
struct hostent resultbuf;
|
|
struct hostent *hst;
|
|
uid_t oldeuid = 0;
|
|
bool use_malloc = false;
|
|
|
|
if (__builtin_expect (debug_level > 0, 0))
|
|
{
|
|
char buf[INET6_ADDRSTRLEN];
|
|
|
|
dbg_log (_("Haven't found \"%s\" in hosts cache!"),
|
|
inet_ntop (AF_INET6, key, buf, sizeof (buf)));
|
|
}
|
|
|
|
if (secure[hstdb])
|
|
{
|
|
oldeuid = geteuid ();
|
|
seteuid (uid);
|
|
}
|
|
|
|
while (__gethostbyname2_r (key, AF_INET6, &resultbuf, buffer, buflen,
|
|
&hst, &h_errno) != 0
|
|
&& h_errno == NETDB_INTERNAL
|
|
&& errno == ERANGE)
|
|
{
|
|
char *old_buffer = buffer;
|
|
errno = 0;
|
|
buflen += 1024;
|
|
|
|
if (__builtin_expect (buflen > 32768, 0))
|
|
{
|
|
buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
|
|
if (buffer == NULL)
|
|
{
|
|
/* We ran out of memory. We cannot do anything but
|
|
sending a negative response. In reality this should
|
|
never happen. */
|
|
hst = NULL;
|
|
buffer = old_buffer;
|
|
break;
|
|
}
|
|
use_malloc = true;
|
|
}
|
|
else
|
|
{
|
|
buffer = (char *) alloca (buflen);
|
|
#if _STACK_GROWS_DOWN
|
|
if (buffer + buflen == old_buffer)
|
|
buflen = 2 * buflen - 1024;
|
|
#elif _STACK_GROWS_UP
|
|
if (old_buffer + buflen - 1024 == buffer)
|
|
{
|
|
buffer = old_buffer;
|
|
buflen = 2 * buflen - 1024;
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
if (secure[hstdb])
|
|
seteuid (oldeuid);
|
|
|
|
cache_addhst (db, fd, req, key, hst, uid);
|
|
|
|
if (use_malloc)
|
|
free (buffer);
|
|
}
|
|
|
|
|
|
void
|
|
addhstbyaddrv6 (struct database *db, int fd, request_header *req,
|
|
void *key, uid_t uid)
|
|
{
|
|
/* Search for the entry matching the key. Please note that we don't
|
|
look again in the table whether the dataset is now available. We
|
|
simply insert it. It does not matter if it is in there twice. The
|
|
pruning function only will look at the timestamp. */
|
|
int buflen = 1024;
|
|
char *buffer = (char *) alloca (buflen);
|
|
struct hostent resultbuf;
|
|
struct hostent *hst;
|
|
uid_t oldeuid = 0;
|
|
bool use_malloc = false;
|
|
|
|
if (__builtin_expect (debug_level > 0, 0))
|
|
{
|
|
char buf[INET6_ADDRSTRLEN];
|
|
dbg_log (_("Haven't found \"%s\" in hosts cache!"),
|
|
inet_ntop (AF_INET6, key, buf, sizeof (buf)));
|
|
}
|
|
|
|
if (secure[hstdb])
|
|
{
|
|
oldeuid = geteuid ();
|
|
seteuid (uid);
|
|
}
|
|
|
|
while (__gethostbyaddr_r (key, NS_IN6ADDRSZ, AF_INET6, &resultbuf,
|
|
buffer, buflen, &hst, &h_errno) != 0
|
|
&& h_errno == NETDB_INTERNAL
|
|
&& errno == ERANGE)
|
|
{
|
|
char *old_buffer = buffer;
|
|
errno = 0;
|
|
buflen += 1024;
|
|
|
|
if (__builtin_expect (buflen > 32768, 0))
|
|
{
|
|
buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
|
|
if (buffer == NULL)
|
|
{
|
|
/* We ran out of memory. We cannot do anything but
|
|
sending a negative response. In reality this should
|
|
never happen. */
|
|
hst = NULL;
|
|
buffer = old_buffer;
|
|
break;
|
|
}
|
|
use_malloc = true;
|
|
}
|
|
else
|
|
{
|
|
buffer = (char *) alloca (buflen);
|
|
#if _STACK_GROWS_DOWN
|
|
if (buffer + buflen == old_buffer)
|
|
buflen = 2 * buflen - 1024;
|
|
#elif _STACK_GROWS_UP
|
|
if (old_buffer + buflen - 1024 == buffer)
|
|
{
|
|
buffer = old_buffer;
|
|
buflen = 2 * buflen - 1024;
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
if (secure[hstdb])
|
|
seteuid (oldeuid);
|
|
|
|
cache_addhst (db, fd, req, key, hst, uid);
|
|
|
|
if (use_malloc)
|
|
free (buffer);
|
|
}
|