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libcares/ares_gethostbyname.c  view on Meta::CPAN

}

static int file_lookup(const char *name, int family, struct hostent **host)
{
  FILE *fp;
  char **alias;
  int status;
  int error;

  /* Per RFC 7686, reject queries for ".onion" domain names with NXDOMAIN. */
  if (ares__is_onion_domain(name))
    return ARES_ENOTFOUND;

#ifdef WIN32
  char PATH_HOSTS[MAX_PATH];
  win_platform platform;

  PATH_HOSTS[0] = '\0';

  platform = ares__getplatform();

  if (platform == WIN_NT) {
    char tmp[MAX_PATH];
    HKEY hkeyHosts;

    if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ,
                     &hkeyHosts) == ERROR_SUCCESS)
    {
      DWORD dwLength = MAX_PATH;
      RegQueryValueExA(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
                      &dwLength);
      ExpandEnvironmentStringsA(tmp, PATH_HOSTS, MAX_PATH);
      RegCloseKey(hkeyHosts);
    }
  }
  else if (platform == WIN_9X)
    GetWindowsDirectoryA(PATH_HOSTS, MAX_PATH);
  else
    return ARES_ENOTFOUND;

  strcat(PATH_HOSTS, WIN_PATH_HOSTS);

#elif defined(WATT32)
  extern const char *_w32_GetHostsFile (void);
  const char *PATH_HOSTS = _w32_GetHostsFile();

  if (!PATH_HOSTS)
    return ARES_ENOTFOUND;
#endif

  fp = fopen(PATH_HOSTS, "r");
  if (!fp)
    {
      error = ERRNO;
      switch(error)
        {
        case ENOENT:
        case ESRCH:
          return ARES_ENOTFOUND;
        default:
          DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
                         error, strerror(error)));
          DEBUGF(fprintf(stderr, "Error opening file: %s\n",
                         PATH_HOSTS));
          *host = NULL;
          return ARES_EFILE;
        }
    }
  while ((status = ares__get_hostent(fp, family, host)) == ARES_SUCCESS)
    {
      if (strcasecmp((*host)->h_name, name) == 0)
        break;
      for (alias = (*host)->h_aliases; *alias; alias++)
        {
          if (strcasecmp(*alias, name) == 0)
            break;
        }
      if (*alias)
        break;
      ares_free_hostent(*host);
    }
  fclose(fp);
  if (status == ARES_EOF)
    status = ARES_ENOTFOUND;
  if (status != ARES_SUCCESS)
    *host = NULL;
  return status;
}

static void sort_addresses(struct hostent *host,
                           const struct apattern *sortlist, int nsort)
{
  struct in_addr a1, a2;
  int i1, i2, ind1, ind2;

  /* This is a simple insertion sort, not optimized at all.  i1 walks
   * through the address list, with the loop invariant that everything
   * to the left of i1 is sorted.  In the loop body, the value at i1 is moved
   * back through the list (via i2) until it is in sorted order.
   */
  for (i1 = 0; host->h_addr_list[i1]; i1++)
    {
      memcpy(&a1, host->h_addr_list[i1], sizeof(struct in_addr));
      ind1 = get_address_index(&a1, sortlist, nsort);
      for (i2 = i1 - 1; i2 >= 0; i2--)
        {
          memcpy(&a2, host->h_addr_list[i2], sizeof(struct in_addr));
          ind2 = get_address_index(&a2, sortlist, nsort);
          if (ind2 <= ind1)
            break;
          memcpy(host->h_addr_list[i2 + 1], &a2, sizeof(struct in_addr));
        }
      memcpy(host->h_addr_list[i2 + 1], &a1, sizeof(struct in_addr));
    }
}

/* Find the first entry in sortlist which matches addr.  Return nsort
 * if none of them match.
 */
static int get_address_index(const struct in_addr *addr,
                             const struct apattern *sortlist,
                             int nsort)
{