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libcares/ares_search.c  view on Meta::CPAN

  const char *p, *q;
  int error;

  /* If the name contains a trailing dot, then the single query is the name
   * sans the trailing dot.
   */
  if ((len > 0) && (name[len - 1] == '.'))
    {
      *s = ares_strdup(name);
      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
    }

  if (!(channel->flags & ARES_FLAG_NOALIASES) && !strchr(name, '.'))
    {
      /* The name might be a host alias. */
      hostaliases = getenv("HOSTALIASES");
      if (hostaliases)
        {
          fp = fopen(hostaliases, "r");
          if (fp)
            {
              while ((status = ares__read_line(fp, &line, &linesize))
                     == ARES_SUCCESS)
                {
                  if (strncasecmp(line, name, len) != 0 ||
                      !ISSPACE(line[len]))
                    continue;
                  p = line + len;
                  while (ISSPACE(*p))
                    p++;
                  if (*p)
                    {
                      q = p + 1;
                      while (*q && !ISSPACE(*q))
                        q++;
                      *s = ares_malloc(q - p + 1);
                      if (*s)
                        {
                          memcpy(*s, p, q - p);
                          (*s)[q - p] = 0;
                        }
                      ares_free(line);
                      fclose(fp);
                      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
                    }
                }
              ares_free(line);
              fclose(fp);
              if (status != ARES_SUCCESS && status != ARES_EOF)
                return status;
            }
          else
            {
              error = ERRNO;
              switch(error)
                {
                case ENOENT:
                case ESRCH:
                  break;
                default:
                  DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
                                 error, strerror(error)));
                  DEBUGF(fprintf(stderr, "Error opening file: %s\n",
                                 hostaliases));
                  *s = NULL;
                  return ARES_EFILE;
                }
            }
        }
    }

  if (channel->flags & ARES_FLAG_NOSEARCH || channel->ndomains == 0)
    {
      /* No domain search to do; just try the name as-is. */
      *s = ares_strdup(name);
      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
    }

  *s = NULL;
  return ARES_SUCCESS;
}