hurd/get-host.c

   1 /* Get a host configuration item kept as the whole contents of a file.
   2 Copyright (C) 1996 Free Software Foundation, Inc.
   3 This file is part of the GNU C Library.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <fcntl.h>
  21 #include <hurd.h>
  22 #include "hurdhost.h"
  23
  24 ssize_t
  25 _hurd_get_host_config (const char *item, char *buf, size_t buflen)
  26 {
  27   error_t err;
  28   char *data;
  29   mach_msg_type_number_t nread, more;
  30   file_t config = __file_name_lookup (item, O_RDONLY, 0);
  31   if (config == MACH_PORT_NULL)
  32     return -1;
  33
  34   data = buf;
  35   err = __io_read (config, &data, &nread, -1, buflen);
  36   if (! err)
  37     /* Check if there is more in the file we didn't read.  */
  38     err = __io_readable (config, &more);
  39   __mach_port_deallocate (__mach_task_self (), config);
  40   if (err)
  41     return __hurd_fail (err);
  42   if (data != buf)
  43     {
  44       memcpy (buf, data, nread);
  45       __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
  46     }
  47
  48   /* Remove newlines in case someone wrote the file by hand.  */
  49   while (buf[nread - 1] == '\n')
  50     buf[--nread] = '\0';
  51
  52   if (more)
  53     /* If we didn't read the whole file, tell the caller to use a bigger
  54        buffer next time.  */
  55     return __hurd_fail (ENAMETOOLONG);
  56
  57   return nread;
  58 }