166 lines
5.3 KiB
Bash
Executable File
166 lines
5.3 KiB
Bash
Executable File
#!/bin/sh
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#
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# check_debian_iso, copyright 2011,2024 Thomas Schmitt <scdbackup@gmx.net>
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# License: GPLv2 or later
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# Tested on: Little-endian GNU/Linux with bash
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# Little-endian FreeBSD-8 with sh and "md5 -q"
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# Little-endian Solaris 5.11 with ksh93
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# Big-endian GNU/Linux with bash
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prog=`basename "$0"`
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usage() {
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echo "Usage: $prog Checksum_file [U:]Item [Image_file] [Checksum_command]" >&2
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echo "Reads the checksum of a Debian installation image from Checksum_file" >&2
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echo "and compares it with the ISO 9660 image in Image_file. Suitable" >&2
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echo "for verifying optical media, because trailing garbage is ignored." >&2
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echo "The Item in the Checksum_file is depicted either by its complete" >&2
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echo "file name (e.g. debian-6.0.3-amd64-CD-1.iso) or by a text piece" >&2
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echo "between '-' and '.iso' in the file name. The first match is used." >&2
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echo "Text pieces for debian-update images must be prefixed by 'U:'." >&2
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echo "If no Image_file is given, then the item file name is used instead." >&2
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echo "Checksum_command is normally deduced from Checksum_file name." >&2
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echo "It must read data from standard input and its first word written" >&2
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echo "to standard output must be the checksum. Default commands are" >&2
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echo "md5sum, sha1sum, sha256sum, sha512sum." >&2
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echo "Examples:" >&2
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echo " $prog MD5SUMS debian-6.0.3-amd64-netinst.iso" >&2
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echo " $prog MD5SUMS netinst" >&2
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echo " $prog MD5SUMS debian-6.0.3-amd64-DVD-1.iso /dev/dvd" >&2
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echo " $prog MD5SUMS 1 /dev/dvd" >&2
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echo " $prog MD5SUMS 2 /dev/dvd" >&2
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echo " $prog MD5SUMS U:1 /dev/dvd" >&2
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echo " $prog MD5SUMS kde-CD-1 /dev/cdrom" >&2
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echo " $prog SHA512SUMS businesscard /dev/cdrom" >&2
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echo " $prog MD5SUMS 1 /dev/cd0 'md5 -q'" >&2
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}
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if test -z "$1" -o "$1" = "-h" -o "$1" = "--help" -o -z "$2"
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then
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usage
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exit 1
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fi
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sums="$1"
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vol="$2"
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file="$3"
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checksummer=md5sum
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if test -n "$4"
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then
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checksummer="$4"
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else
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base=`basename "$sums"`
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if test "$base" = "SHA1SUMS"
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then
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checksummer=sha1sum
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elif test "$base" = "SHA256SUMS"
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then
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checksummer=sha256sum
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elif test "$base" = "SHA512SUMS"
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then
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checksummer=sha512sum
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fi
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fi
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update=""
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update_v="-v"
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use_fgrep=""
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if echo "$vol" | grep '^debian-.*\.iso$' >/dev/null
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then
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use_fgrep=1
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elif echo "$vol" | grep '^U:' >/dev/null
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then
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update=" update"
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update_v=""
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vol=`echo "$vol" | sed -e 's/^U://'`
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fi
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if test -n "$use_fgrep"
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then
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line_from_list=`fgrep "$vol" "$sums" | head -1`
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else
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line_from_list=`grep '.*-'"$vol"'\.iso$' "$sums" | grep $update_v "update" | head -1`
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fi
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sum_from_list=`echo "$line_from_list" | awk '{print $1}'`
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name_from_list=`echo "$line_from_list" | awk '{print $2}'`
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if test -z "$sum_from_list"
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then
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if test -n "$use_fgrep"
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then
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echo "Could not find item '${vol}' in '$sums'" >&2
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else
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echo "Could not find$update item '.*-${vol}.iso' in '$sums'" >&2
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fi
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exit 4
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fi
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if test -z "$file"
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then
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file="$name_from_list"
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fi
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# Logical block size is assumed with 2048 bytes. Neither genisoimage
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# nor xorriso produce other sizes, and even the Linux kernel seems to
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# have this size hardcoded.
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# At byte 16 * 2048 starts the Primary Volume Descriptor (superblock)
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# of the image. The magic number values should be ECMA-119 Volume
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# Descriptor Type 0x01 and Standard Identifier "CD001".
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# The way how these 6 bytes group to 16-bit words indicates the byte
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# sex (endianness) of the local machine. The ECMA-119 Volume Space Size
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# is stored as little-endian 32-bit number at PVD byte 80, and as big-endian
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# 32-bit number at PVD byte 84.
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# od -d is used because it guarantees unsigned integer of predictable
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# size. Formats -i and -l depend on sizeof(int).
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magic=`(dd if="$file" bs=2048 skip=16 count=1 |
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dd bs=1 count=6 | od -x | head -1 | \
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awk '{print $2 " " $3 " " $4}') 2>/dev/null`
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if test "$magic" = "4301 3044 3130"
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then
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lo=`(dd if="$file" bs=2048 skip=16 count=1 | \
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dd bs=1 skip=80 count=2 | od -d | head -1 | \
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awk '{print $2}') 2>/dev/null`
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hi=`(dd if="$file" bs=2048 skip=16 count=1 | \
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dd bs=1 skip=82 count=2 | od -d | head -1 | \
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awk '{print $2}') 2>/dev/null`
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elif test "$magic" = "0143 4430 3031"
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then
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lo=`(dd if="$file" bs=2048 skip=16 count=1 | \
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dd bs=1 skip=86 count=2 | od -d | head -1 | \
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awk '{print $2}') 2>/dev/null`
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hi=`(dd if="$file" bs=2048 skip=16 count=1 | \
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dd bs=1 skip=84 count=2 | od -d | head -1 | \
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awk '{print $2}') 2>/dev/null`
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elif test -e "$file"
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then
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echo "Does not look like an ISO 9660 filesystem: '$file' magic='$magic'" >&2
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exit 2
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else
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echo "File not found: '$file'" >&2
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exit 5
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fi
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# The two 16 bit numbers, which are of the appropriate byte sex,
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# get combined to a 32 bit number.
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blocks=`expr "$lo" + "$hi" '*' 65536`
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echo "Piping $blocks blocks of '$file' through '$checksummer'" >&2
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echo "to verify checksum list item '$name_from_list'." >&2
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sum_from_file=`dd if="$file" bs=2048 count="$blocks" | $checksummer | head -1 | awk '{print $1}'`
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if test "$sum_from_list" = "$sum_from_file"
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then
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echo "Ok: '$file' matches$update '$name_from_list' in '$sums'"
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else
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echo "Found: $sum_from_file" >&2
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echo "Expected: $sum_from_list" >&2
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echo "MISMATCH: '$file' checksum differs from '$name_from_list' in '$sums'"
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exit 3
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fi
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exit 0
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