path: root/nscd/hstcache.c

/* Cache handling for host lookup.
   Copyright (C) 1998-2002, 2003, 2004 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 <alloca.h>
#include <assert.h>
#include <errno.h>
#include <error.h>
#include <libintl.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 <arpa/inet.h>
#include <arpa/nameser.h>
#include <sys/mman.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
};


static void
cache_addhst (struct database_dyn *db, int fd, request_header *req,
	      const void *key, struct hostent *hst, uid_t owner, int add_addr,
	      struct hashentry *he, struct datahead *dh, int errval)
{
  ssize_t total;
  ssize_t written;
  time_t t = time (NULL);

  /* We allocate all data in one memory block: the iov vector,
     the response header and the dataset itself.  */
  struct dataset
  {
    struct datahead head;
    hst_response_header resp;
    char strdata[0];
  } *dataset;

  assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));

  if (hst == NULL)
    {
      if (he != NULL && errval == EAGAIN)
	{
	  /* If we have an old record available but cannot find one
	     now because the service is not available we keep the old
	     record and make sure it does not get removed.  */
	  if (reload_count != UINT_MAX)
	    /* Do not reset the value if we never not reload the record.  */
	    dh->nreloads = reload_count - 1;