grub-savannah-mirror/grub-core/lib/getline.c

/* main.c - the normal mode main routine */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2000,2001,2002,2003,2005,2006,2007,2008,2009,2013  Free Software Foundation, Inc.
 *
 *  GRUB 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/kernel.h>
#include <grub/normal.h>
#include <grub/dl.h>
#include <grub/misc.h>
#include <grub/file.h>
#include <grub/mm.h>
#include <grub/term.h>
#include <grub/env.h>
#include <grub/parser.h>
#include <grub/reader.h>
#include <grub/menu_viewer.h>
#include <grub/auth.h>
#include <grub/i18n.h>
#include <grub/charset.h>
#include <grub/script_sh.h>

/* Read a line from the file FILE.  */
char *
grub_file_getline (grub_file_t file)
{
  char c;
  grub_size_t pos = 0;
  char *cmdline;
  int have_newline = 0;
  grub_size_t max_len = 64;

  /* Initially locate some space.  */
  cmdline = grub_malloc (max_len);
  if (! cmdline)
    return 0;

  while (1)
    {
      if (grub_file_read (file, &c, 1) != 1)
	break;

      /* Skip all carriage returns.  */
      if (c == '\r')
	continue;


      if (pos + 1 >= max_len)
	{
	  char *old_cmdline = cmdline;
	  max_len = max_len * 2;
	  cmdline = grub_realloc (cmdline, max_len);
	  if (! cmdline)
	    {
	      grub_free (old_cmdline);
	      return 0;
	    }
	}

      if (c == '\n')
	{
	  have_newline = 1;
	  break;
	}

      cmdline[pos++] = c;
    }

  cmdline[pos] = '\0';

  /* If the buffer is empty, don't return anything at all.  */
  if (pos == 0 && !have_newline)
    {
      grub_free (cmdline);
      cmdline = 0;
    }

  return cmdline;
}