Contents of /trunk/scripts/bootsector

#! /bin/bash
# bash is important because for echo -e

# edit the magic number of boot sector (the last two bytes)
# (c) 2001, Thomas Lange, lange@informatik.uni-koeln.de

seek=510

usage() {

cat <<EOF
    bootsector [-edlvh] device

Read or write the magic number (the last two bytes) of a boot
sector. Writing 0x0000 to it disables booting from this boot sector.
The value 0xAA55 enables booting from this boot sector.

    -e    enable the boot sector
    -d    disable the boot sector
    -l    list the magic number hexadecimal
    -v    list the magic number in a verbose way
    -h    print this help

Examples:

# bootsector -e /dev/hda
# bootsector -l /dev/hda
0000000 aa55
# bootsector -d /dev/hda
# bootsector -l /dev/hda
0000000 0000
# bootsector -v /dev/hda
Boot sector /dev/hda disabled.

bootsector is written by Thomas Lange, lange@informatik.uni-koeln.de, 2001.

EOF
exit 0
}

readbb() { # read last two bytes from boot block

    dd bs=1c skip=$seek count=2 if=$1 2>/dev/null|od -x|grep -v 0000002
}

writebb() { # write last two bytes of boot block

    dd bs=1c seek=$seek of=$1 2>/dev/null || echo "Can't write to boot block $1"
}

arch=`dpkg --print-installation-architecture`
[ "$arch" = "i386" ] || {
    Currently, only i386 architecure is supported.
    exit 1
}

getopts e:d:l:v:h opt
case $opt in
    h) usage ;;
    e) echo -ne "\x55\xaa" | writebb $OPTARG ;;
    d) echo -ne "\x0\x0"   | writebb $OPTARG ;;
    l) readbb $OPTARG ;;
    v) bs=`readbb $OPTARG`
       case $bs in
            "0000000 0000") echo "Boot sector $OPTARG is disabled." ;;
            "0000000 aa55") echo "Boot sector $OPTARG is enabled." ;;
            *) echo "Unknown boot sector $bs" ;;
       esac
       ;;
    *) usage; exit 1 ;;
esac
1	lange	608	#! /bin/bash
2			# bash is important because for echo -e
3
4			# edit the magic number of boot sector (the last two bytes)
5			# (c) 2001, Thomas Lange, lange@informatik.uni-koeln.de
6
7			seek=510
8
9			usage() {
10
11			cat <<EOF
12	lange	615	bootsector [-edlvh] device
13	lange	608
14	lange	615	Read or write the magic number (the last two bytes) of a boot
15			sector. Writing 0x0000 to it disables booting from this boot sector.
16			The value 0xAA55 enables booting from this boot sector.
17	lange	608
18			-e enable the boot sector
19			-d disable the boot sector
20	lange	609	-l list the magic number hexadecimal
21	lange	615	-v list the magic number in a verbose way
22			-h print this help
23	lange	608
24			Examples:
25
26			# bootsector -e /dev/hda
27			# bootsector -l /dev/hda
28			0000000 aa55
29			# bootsector -d /dev/hda
30			# bootsector -l /dev/hda
31			0000000 0000
32			# bootsector -v /dev/hda
33			Boot sector /dev/hda disabled.
34	lange	615
35			bootsector is written by Thomas Lange, lange@informatik.uni-koeln.de, 2001.
36
37	lange	608	EOF
38	lange	615	exit 0
39	lange	608	}
40
41	lange	615	readbb() { # read last two bytes from boot block
42	lange	608
43	lange	615	dd bs=1c skip=$seek count=2 if=$1 2>/dev/null\|od -x\|grep -v 0000002
44			}
45
46			writebb() { # write last two bytes of boot block
47
48			dd bs=1c seek=$seek of=$1 2>/dev/null \|\| echo "Can't write to boot block $1"
49			}
50
51	lange	609	arch=`dpkg --print-installation-architecture`
52			[ "$arch" = "i386" ] \|\| {
53	lange	615	Currently, only i386 architecure is supported.
54	lange	609	exit 1
55			}
56
57	lange	615	getopts e:d:l:v:h opt
58			case $opt in
59			h) usage ;;
60			e) echo -ne "\x55\xaa" \| writebb $OPTARG ;;
61			d) echo -ne "\x0\x0" \| writebb $OPTARG ;;
62			l) readbb $OPTARG ;;
63			v) bs=`readbb $OPTARG`
64			case $bs in
65			"0000000 0000") echo "Boot sector $OPTARG is disabled." ;;
66			"0000000 aa55") echo "Boot sector $OPTARG is enabled." ;;
67			*) echo "Unknown boot sector $bs" ;;
68			esac
69			;;
70			*) usage; exit 1 ;;
71	lange	609	esac
Name	Value
svn:eol-style	native
svn:executable	*
svn:keywords	Author Date Id Revision