grub/commands/cmp.c
subdino 68c864ebb6 2005-07-09 Vincent Pelletier <subdino2004@yahoo.fr>
* commands/cmp.c (BUFFER_SIZE): New macro.
	(grub_cmd_cmp): Close the right file at the right time.  Compare
	only data just read.  Don't report files of different  size as
	identical.  Dynamically allocate buffers.  Move variable
	declarations at the beginning of function.
2005-07-09 16:29:02 +00:00

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/* cmd.c - command to cmp an operating system */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003 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 2 of the License, 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 GRUB; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <grub/normal.h>
#include <grub/dl.h>
#include <grub/arg.h>
#include <grub/misc.h>
#include <grub/file.h>
#include <grub/mm.h>
#define BUFFER_SIZE 512
static grub_err_t
grub_cmd_cmp (struct grub_arg_list *state __attribute__ ((unused)),
int argc, char **args)
{
grub_err_t err;
grub_ssize_t rd1, rd2;
grub_uint32_t pos;
grub_file_t file1 = 0;
grub_file_t file2 = 0;
char *buf1 = 0;
char *buf2 = 0;
if (argc != 2)
return grub_error (GRUB_ERR_BAD_ARGUMENT, "two arguments required");
grub_printf ("Compare `%s' and `%s':\n", args[0],
args[1]);
if (! (file1 = grub_file_open (args[0]) ) ||
! (file2 = grub_file_open (args[1]) ) )
goto cleanup;
if (grub_file_size (file1) != grub_file_size (file2))
grub_printf ("Differ in size: %d [%s], %d [%s]\n",
grub_file_size (file1), args[0],
grub_file_size (file2), args[1]);
else
{
pos = 0;
if (! (buf1 = (char *) grub_malloc (BUFFER_SIZE) ) ||
! (buf2 = (char *) grub_malloc (BUFFER_SIZE) ) )
goto cleanup;
do
{
int i;
rd1 = grub_file_read (file1, buf1, BUFFER_SIZE);
rd2 = grub_file_read (file2, buf2, BUFFER_SIZE);
if (rd1 != rd2)
goto cleanup;
for (i = 0; i < rd2; i++)
{
if (buf1[i] != buf2[i])
{
grub_printf ("Differ at the offset %d: 0x%x [%s], 0x%x [%s]\n",
i + pos, buf1[i], args[0],
buf2[i], args[1]);
goto cleanup;
}
}
pos += BUFFER_SIZE;
} while (rd2);
grub_printf ("The files are identical.\n");
}
cleanup:
err=grub_errno;
if (buf1)
grub_free (buf1);
if (buf2)
grub_free (buf2);
if (file1)
grub_file_close (file1);
if (file2)
grub_file_close (file2);
return err;
}
#ifdef GRUB_UTIL
void
grub_cmp_init (void)
{
grub_register_command ("cmp", grub_cmd_cmp, GRUB_COMMAND_FLAG_BOTH,
"cmp FILE1 FILE2", "Compare two files", 0);
}
void
grub_cmp_fini (void)
{
grub_unregister_command ("cmp");
}
#else /* ! GRUB_UTIL */
GRUB_MOD_INIT
{
(void)mod; /* To stop warning. */
grub_register_command ("cmp", grub_cmd_cmp, GRUB_COMMAND_FLAG_BOTH,
"cmp FILE1 FILE2", "Compare two files", 0);
}
GRUB_MOD_FINI
{
grub_unregister_command ("cmp");
}
#endif /* ! GRUB_UTIL */