455 lines
13 KiB
C
455 lines
13 KiB
C
/* Cache handling for host lookup.
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Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <assert.h>
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#include <errno.h>
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#include <error.h>
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#include <netdb.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <libintl.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include "nscd.h"
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#include "dbg_log.h"
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/* This is the standard reply in case the service is disabled. */
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static const hst_response_header disabled =
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{
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version: NSCD_VERSION,
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found: -1,
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h_name_len: 0,
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h_aliases_cnt: 0,
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h_addrtype: -1,
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h_length: -1,
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h_addr_list_cnt: 0,
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error: NETDB_INTERNAL
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};
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/* This is the struct describing how to write this record. */
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const struct iovec hst_iov_disabled =
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{
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iov_base: (void *) &disabled,
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iov_len: sizeof (disabled)
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};
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/* This is the standard reply in case we haven't found the dataset. */
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static const hst_response_header notfound =
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{
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version: NSCD_VERSION,
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found: 0,
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h_name_len: 0,
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h_aliases_cnt: 0,
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h_addrtype: -1,
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h_length: -1,
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h_addr_list_cnt: 0,
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error: HOST_NOT_FOUND
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};
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/* This is the struct describing how to write this record. */
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static const struct iovec iov_notfound =
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{
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iov_base: (void *) ¬found,
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iov_len: sizeof (notfound)
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};
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struct hostdata
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{
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hst_response_header resp;
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char strdata[0];
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};
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static void
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cache_addhst (struct database *db, int fd, request_header *req, void *key,
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struct hostent *hst, uid_t owner)
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{
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ssize_t total;
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ssize_t written;
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time_t t = time (NULL);
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if (hst == NULL)
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{
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/* We have no data. This means we send the standard reply for this
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case. */
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void *copy;
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total = sizeof (notfound);
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written = writev (fd, &iov_notfound, 1);
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copy = malloc (req->key_len);
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if (copy == NULL)
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error (EXIT_FAILURE, errno, _("while allocating key copy"));
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memcpy (copy, key, req->key_len);
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/* Compute the timeout time. */
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t += db->negtimeout;
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/* Now get the lock to safely insert the records. */
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pthread_rwlock_rdlock (&db->lock);
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cache_add (req->type, copy, req->key_len, ¬found,
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sizeof (notfound), (void *) -1, 0, t, db, owner);
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pthread_rwlock_unlock (&db->lock);
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}
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else
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{
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/* Determine the I/O structure. */
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struct hostdata *data;
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size_t h_name_len = strlen (hst->h_name) + 1;
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size_t h_aliases_cnt;
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uint32_t *h_aliases_len;
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size_t h_addr_list_cnt;
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int addr_list_type;
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char *addresses;
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char *aliases;
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char *key_copy = NULL;
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char *cp;
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size_t cnt;
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/* Determine the number of aliases. */
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h_aliases_cnt = 0;
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for (cnt = 0; hst->h_aliases[cnt] != NULL; ++cnt)
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++h_aliases_cnt;
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/* Determine the length of all aliases. */
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h_aliases_len = (uint32_t *) alloca (h_aliases_cnt * sizeof (uint32_t));
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total = 0;
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for (cnt = 0; cnt < h_aliases_cnt; ++cnt)
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{
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h_aliases_len[cnt] = strlen (hst->h_aliases[cnt]) + 1;
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total += h_aliases_len[cnt];
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}
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/* Determine the number of addresses. */
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h_addr_list_cnt = 0;
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for (cnt = 0; hst->h_addr_list[cnt]; ++cnt)
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++h_addr_list_cnt;
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/* We allocate all data in one memory block: the iov vector,
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the response header and the dataset itself. */
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total += (sizeof (struct hostdata)
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+ h_name_len
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+ h_aliases_cnt * sizeof (uint32_t)
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+ h_addr_list_cnt * hst->h_length);
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data = (struct hostdata *) malloc (total + req->key_len);
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if (data == NULL)
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/* There is no reason to go on. */
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error (EXIT_FAILURE, errno, _("while allocating cache entry"));
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data->resp.found = 1;
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data->resp.h_name_len = h_name_len;
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data->resp.h_aliases_cnt = h_aliases_cnt;
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data->resp.h_addrtype = hst->h_addrtype;
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data->resp.h_length = hst->h_length;
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data->resp.h_addr_list_cnt = h_addr_list_cnt;
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data->resp.error = NETDB_SUCCESS;
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cp = data->strdata;
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cp = mempcpy (cp, hst->h_name, h_name_len);
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cp = mempcpy (cp, h_aliases_len, h_aliases_cnt * sizeof (uint32_t));
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/* The normal addresses first. */
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addresses = cp;
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for (cnt = 0; cnt < h_addr_list_cnt; ++cnt)
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cp = mempcpy (cp, hst->h_addr_list[cnt], hst->h_length);
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/* Then the aliases. */
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aliases = cp;
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for (cnt = 0; cnt < h_aliases_cnt; ++cnt)
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cp = mempcpy (cp, hst->h_aliases[cnt], h_aliases_len[cnt]);
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assert (cp == data->strdata + total - sizeof (hst_response_header));
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/* If we are adding a GETHOSTBYNAME{,v6} entry we must be prepared
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that the answer we get from the NSS does not contain the key
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itself. This is the case if the resolver is used and the name
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is extended by the domainnames from /etc/resolv.conf. Therefore
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we explicitly add the name here. */
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if (req->type == GETHOSTBYNAME || req->type == GETHOSTBYNAMEv6)
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key_copy = memcpy (cp, key, req->key_len);
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/* We write the dataset before inserting it to the database
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since while inserting this thread might block and so would
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unnecessarily let the receiver wait. */
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written = write (fd, data, total);
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addr_list_type = (hst->h_length == NS_INADDRSZ
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? GETHOSTBYADDR : GETHOSTBYADDRv6);
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/* Compute the timeout time. */
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t += db->postimeout;
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/* Now get the lock to safely insert the records. */
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pthread_rwlock_rdlock (&db->lock);
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/* First add all the aliases. If the record contains more than
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one IP address (used for load balancing etc) don't cache the
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entry. This is something the current cache handling cannot
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handle and it is more than questionable whether it is
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worthwhile complicating the cache handling just for handling
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such a special case. */
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if (hst->h_addr_list[1] == NULL)
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for (cnt = 0; cnt < h_aliases_cnt; ++cnt)
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{
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if (addr_list_type == GETHOSTBYADDR)
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cache_add (GETHOSTBYNAME, aliases, h_aliases_len[cnt], data,
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total, data, 0, t, db, owner);
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cache_add (GETHOSTBYNAMEv6, aliases, h_aliases_len[cnt], data,
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total, data, 0, t, db, owner);
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aliases += h_aliases_len[cnt];
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}
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/* Next the normal addresses. */
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for (cnt = 0; cnt < h_addr_list_cnt; ++cnt)
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{
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cache_add (addr_list_type, addresses, hst->h_length, data, total,
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data, 0, t, db, owner);
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addresses += hst->h_length;
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}
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/* If necessary the IPv6 addresses. */
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if (addr_list_type == GETHOSTBYADDR)
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for (cnt = 0; cnt < h_addr_list_cnt; ++cnt)
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{
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cache_add (GETHOSTBYADDRv6, addresses, IN6ADDRSZ, data, total,
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data, 0, t, db, owner);
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addresses += IN6ADDRSZ;
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}
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/* Avoid adding names if more than one address is available. See
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above for more info. */
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if (hst->h_addr_list[1] == NULL)
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{
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/* If necessary add the key for this request. */
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if (req->type == GETHOSTBYNAME || req->type == GETHOSTBYNAMEv6)
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{
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if (addr_list_type == GETHOSTBYADDR)
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cache_add (GETHOSTBYNAME, key_copy, req->key_len, data, total,
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data, 0, t, db, owner);
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cache_add (GETHOSTBYNAMEv6, key_copy, req->key_len, data,
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total, data, 0, t, db, owner);
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}
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/* And finally the name. We mark this as the last entry. */
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if (addr_list_type == GETHOSTBYADDR)
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cache_add (GETHOSTBYNAME, data->strdata, h_name_len, data, total,
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data, 0, t, db, owner);
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cache_add (GETHOSTBYNAMEv6, data->strdata, h_name_len, data,
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total, data, 1, t, db, owner);
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}
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pthread_rwlock_unlock (&db->lock);
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}
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if (written != total)
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{
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char buf[256];
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dbg_log (_("short write in %s: %s"), __FUNCTION__,
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strerror_r (errno, buf, sizeof (buf)));
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}
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}
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void
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addhstbyname (struct database *db, int fd, request_header *req,
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void *key, uid_t uid)
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{
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/* Search for the entry matching the key. Please note that we don't
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look again in the table whether the dataset is now available. We
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simply insert it. It does not matter if it is in there twice. The
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pruning function only will look at the timestamp. */
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int buflen = 512;
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char *buffer = alloca (buflen);
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struct hostent resultbuf;
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struct hostent *hst;
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uid_t oldeuid = 0;
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if (debug_level > 0)
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dbg_log (_("Haven't found \"%s\" in hosts cache!"), (char *)key);
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if (secure[hstdb])
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{
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oldeuid = geteuid ();
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seteuid (uid);
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}
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while (__gethostbyname2_r (key, AF_INET, &resultbuf, buffer, buflen,
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&hst, &h_errno) != 0
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&& h_errno == NETDB_INTERNAL
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&& errno == ERANGE)
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{
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errno = 0;
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buflen += 256;
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buffer = alloca (buflen);
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}
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if (secure[hstdb])
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seteuid (oldeuid);
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cache_addhst (db, fd, req, key, hst, uid);
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}
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void
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addhstbyaddr (struct database *db, int fd, request_header *req,
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void *key, uid_t uid)
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{
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/* Search for the entry matching the key. Please note that we don't
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look again in the table whether the dataset is now available. We
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simply insert it. It does not matter if it is in there twice. The
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pruning function only will look at the timestamp. */
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int buflen = 512;
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char *buffer = alloca (buflen);
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struct hostent resultbuf;
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struct hostent *hst;
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uid_t oldeuid = 0;
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if (debug_level > 0)
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{
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char buf[INET_ADDRSTRLEN];
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dbg_log (_("Haven't found \"%s\" in hosts cache!"),
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inet_ntop (AF_INET, key, buf, sizeof (buf)));
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}
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if (secure[hstdb])
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{
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oldeuid = geteuid ();
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seteuid (uid);
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}
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while (__gethostbyaddr_r (key, NS_INADDRSZ, AF_INET, &resultbuf, buffer,
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buflen, &hst, &h_errno) != 0
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&& h_errno == NETDB_INTERNAL
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&& errno == ERANGE)
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{
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errno = 0;
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buflen += 256;
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buffer = alloca (buflen);
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}
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if (secure[hstdb])
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seteuid (oldeuid);
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cache_addhst (db, fd, req, key, hst, uid);
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}
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void
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addhstbynamev6 (struct database *db, int fd, request_header *req,
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void *key, uid_t uid)
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{
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/* Search for the entry matching the key. Please note that we don't
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look again in the table whether the dataset is now available. We
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simply insert it. It does not matter if it is in there twice. The
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pruning function only will look at the timestamp. */
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int buflen = 512;
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char *buffer = alloca (buflen);
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struct hostent resultbuf;
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struct hostent *hst;
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uid_t oldeuid = 0;
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if (debug_level > 0)
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{
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char buf[INET6_ADDRSTRLEN];
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dbg_log (_("Haven't found \"%s\" in hosts cache!"),
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inet_ntop (AF_INET6, key, buf, sizeof (buf)));
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}
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if (secure[hstdb])
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{
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oldeuid = geteuid ();
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seteuid (uid);
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}
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while (__gethostbyname2_r (key, AF_INET6, &resultbuf, buffer, buflen,
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&hst, &h_errno) != 0
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&& h_errno == NETDB_INTERNAL
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&& errno == ERANGE)
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{
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errno = 0;
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buflen += 256;
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buffer = alloca (buflen);
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}
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if (secure[hstdb])
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seteuid (oldeuid);
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cache_addhst (db, fd, req, key, hst, uid);
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}
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void
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addhstbyaddrv6 (struct database *db, int fd, request_header *req,
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void *key, uid_t uid)
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{
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/* Search for the entry matching the key. Please note that we don't
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look again in the table whether the dataset is now available. We
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simply insert it. It does not matter if it is in there twice. The
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pruning function only will look at the timestamp. */
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int buflen = 512;
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char *buffer = alloca (buflen);
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struct hostent resultbuf;
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struct hostent *hst;
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uid_t oldeuid = 0;
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if (debug_level > 0)
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{
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char buf[INET6_ADDRSTRLEN];
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dbg_log (_("Haven't found \"%s\" in hosts cache!"),
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inet_ntop (AF_INET6, key, buf, sizeof (buf)));
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}
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if (secure[hstdb])
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{
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oldeuid = geteuid ();
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seteuid (uid);
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}
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while (__gethostbyaddr_r (key, NS_IN6ADDRSZ, AF_INET6, &resultbuf,
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buffer, buflen, &hst, &h_errno) != 0
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&& h_errno == NETDB_INTERNAL
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&& errno == ERANGE)
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{
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errno = 0;
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buflen += 256;
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buffer = alloca (buflen);
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}
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if (secure[hstdb])
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seteuid (oldeuid);
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cache_addhst (db, fd, req, key, hst, uid);
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}
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