coreutils/lib/xgethostname.c

/* xgethostname.c -- return current hostname with unlimited length
   Copyright (C) 1992 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Written by Jim Meyering, meyering@comco.com */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <sys/types.h>

int gethostname ();
char *xmalloc ();
char *xrealloc ();

#ifndef INITIAL_HOSTNAME_LENGTH
# define INITIAL_HOSTNAME_LENGTH 33
#endif

char *
xgethostname ()
{
  char *hostname;
  size_t size;
  int err;

  size = INITIAL_HOSTNAME_LENGTH;
  hostname = xmalloc (size);
  while (1)
    {
      hostname[size - 1] = '\0';
      err = gethostname (hostname, size);
      if (err == 0 && hostname[size - 1] == '\0')
	break;
      size *= 2;
      hostname = xrealloc (hostname, size);
    }

  return hostname;
}