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/* mbchk - a simple checker for the format of a Multiboot kernel */
/*
* Copyright (C) 1999,2001,2002 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 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
/* for standalone */
#define GRUB_MAGIC 0x1BADB002
typedef struct multiboot_header
{
unsigned long magic;
unsigned long flags;
unsigned long checksum;
unsigned long header_addr;
unsigned long load_addr;
unsigned long load_end_addr;
unsigned long bss_end_addr;
unsigned long entry_addr;
} multiboot_header_t;
static int quiet = 0;
static char *optstring = "hvq";
static struct option longopts[] =
{
{"help", no_argument, 0, 'h'},
{"version", no_argument, 0, 'v'},
{"quiet", no_argument, 0, 'q'},
{0}
};
static void
usage (int status)
{
if (status)
fprintf (stderr, "Try ``mbchk --help'' for more information.\n");
else
printf ("Usage: mbchk [OPTION]... [FILE]...\n"
"Check if the format of FILE complies with the Multiboot Specification.\n"
"\n"
"-q, --quiet suppress all normal output\n"
"-h, --help display this help and exit\n"
"-v, --version output version information and exit.\n"
"\n"
"Report bugs to <[email protected]>.\n");
exit (status);
}
static int
check_multiboot (const char *filename, FILE *fp)
{
multiboot_header_t *mbh = 0;
int i;
char buf[8192];
if (fread (buf, 1, 8192, fp) < 0)
{
fprintf (stderr, "%s: Read error.\n", filename);
return 0;
}
for (i = 0; i < 8192 - sizeof (multiboot_header_t); i++)
{
unsigned long magic = *((unsigned long *) (buf + i));
if (magic == GRUB_MAGIC)
{
mbh = (multiboot_header_t *) (buf + i);
break;
}
}
if (! mbh)
{
fprintf (stderr, "%s: No Multiboot header.\n", filename);
return 0;
}
if (! quiet)
printf ("%s: The Multiboot header is found at the offset %d.\n",
filename, i);
/* Check for the checksum. */
if (mbh->magic + mbh->flags + mbh->checksum != 0)
{
fprintf (stderr,
"%s: Bad checksum (0x%lx).\n",
filename, mbh->checksum);
return 0;
}
/* Reserved flags must be zero. */
if (mbh->flags & ~0x00010003)
{
fprintf (stderr,
"%s: Non-zero is found in reserved flags (0x%lx).\n",
filename, mbh->flags);
return 0;
}
if (! quiet)
{
printf ("%s: Page alignment is turned %s.\n",
filename, (mbh->flags & 0x1)? "on" : "off");
printf ("%s: Memory information is turned %s.\n",
filename, (mbh->flags & 0x2)? "on" : "off");
printf ("%s: Address fields is turned %s.\n",
filename, (mbh->flags & 0x10000)? "on" : "off");
}
/* Check for the address fields. */
if (mbh->flags & 0x10000)
{
if (mbh->header_addr < mbh->load_addr)
{
fprintf (stderr,
"%s: header_addr is less than "
"load_addr (0x%lx > 0x%lx).\n",
filename, mbh->header_addr, mbh->load_addr);
return 0;
}
if (mbh->load_end_addr && mbh->load_addr >= mbh->load_end_addr)
{
fprintf (stderr,
"%s: load_addr is not less than load_end_addr"
" (0x%lx >= 0x%lx).\n",
filename, mbh->load_addr, mbh->load_end_addr);
return 0;
}
if (mbh->bss_end_addr && mbh->load_end_addr > mbh->bss_end_addr)
{
fprintf (stderr,
"%s: load_end_addr is greater than bss_end_addr"
" (0x%lx > 0x%lx).\n",
filename, mbh->load_end_addr, mbh->bss_end_addr);
return 0;
}
if (mbh->load_addr > mbh->entry_addr)
{
fprintf (stderr,
"%s: load_addr is greater than entry_addr"
" (0x%lx > 0x%lx).\n",
filename, mbh->load_addr, mbh->entry_addr);
return 0;
}
/* FIXME: It is better to check if the entry address is within the
file, especially when the load end address is zero. */
if (mbh->load_end_addr && mbh->load_end_addr <= mbh->entry_addr)
{
fprintf (stderr,
"%s: load_end_addr is not greater than entry_addr"
" (0x%lx <= 0x%lx).\n",
filename, mbh->load_end_addr, mbh->entry_addr);
return 0;
}
/* This is a GRUB-specific limitation. */
if (mbh->load_addr < 0x100000)
{
fprintf (stderr,
"%s: Cannot be loaded at less than 1MB by GRUB"
" (0x%lx).\n",
filename, mbh->load_addr);
return 0;
}
}
if (! quiet)
printf ("%s: All checks passed.\n", filename);
return 1;
}
int
main (int argc, char *argv[])
{
int c;
do
{
c = getopt_long (argc, argv, optstring, longopts, 0);
switch (c)
{
case EOF:
break;
case 'h':
usage (0);
break;
case 'v':
printf ("mbchk (Ported standalone from Grub Legacy)\n");
exit (0);
break;
case 'q':
quiet = 1;
break;
default:
usage (1);
break;
}
}
while (c != EOF);
if (optind < argc)
{
while (optind < argc)
{
FILE *fp;
fp = fopen (argv[optind], "r");
if (! fp)
{
fprintf (stderr, "%s: No such file.\n", argv[optind]);
exit (1);
}
if (! check_multiboot (argv[optind], fp))
exit (1);
fclose (fp);
optind++;
}
}
else
{
if (! check_multiboot ("<stdin>", stdin))
exit (1);
}
return 0;
}
