glibc/sysdeps/mach/hurd/sethostid.c

/* Copyright (C) 1993, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <unistd.h>
#include <hurd.h>
#include "hurdhost.h"
#include "../stdio-common/_itoa.h"

/* Set the current machine's Internet number to ID.
   This call is restricted to the super-user.  */
int
DEFUN(sethostid, (id), long int id)
{
  char buf[8], *bp;
  ssize_t n;

  /* The hostid is kept in the file /etc/hostid,
     eight characters of upper-case hexadecimal.  */

  bp = _itoa_word (id, &buf[sizeof buf], 16, 1);
  while (bp > buf)
    *--bp = '0';

  n = _hurd_set_host_config ("/etc/hostid", buf, sizeof buf);
  return n < 0 ? -1 : 0;
}