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Diffstat (limited to 'cli/get-eltorito.pl')
| -rwxr-xr-x | cli/get-eltorito.pl | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/cli/get-eltorito.pl b/cli/get-eltorito.pl new file mode 100755 index 0000000..d237728 --- /dev/null +++ b/cli/get-eltorito.pl @@ -0,0 +1,228 @@ +#!/usr/bin/env perl + +use Getopt::Std; + +# +# geteltorito.pl: a bootimage extractor +# Script that will extract the first El Torito bootimage from a +# bootable CD image +# R. Krienke 08/2001 +# krienke@uni-koblenz.de +# License: GPL +# +# Get latest version from: +# http://userpages.uni-koblenz.de/~krienke/ftp/noarch/geteltorito +# +$utilVersion="0.6"; +# +# Version 0.6 +# 2015/02/25 +# I included a patch by Daniel Kekez, daniel.kekez@utoronto.ca to make geteltorito +# better compatible with windows: +# "To run this Perl script using using Strawberry Perl under Windows, I +# found it was necessary to explicitly open the files in binary mode since +# Windows will default to text mode when open() is called." +# Version 0.5 +# 2009/06/22 +# A patch for harddisk emulation images from <colimit@gmail.com>. +# For BootMediaType=4 (harddisk emulation) SectorCount is always 1, and geteltorito.pl +# returns just MBR. This patch guesses the correct bootimage size +# from MBR (offset+size of the first partitition). +# Version 0.4 +# 2007/02/01 +# A patch from Santiago Garcia <manty@debian.org> to use a virtual sector +# size (vSecSize) of 512 bytes, as defined on "El Torito" specs and change +# unpack of the sector count from n to v to get the correct sector count. +# Version 0.3 +# 2006/02/21 +# A patch from Ben Collins <bcollins@ubuntu.com> to make the +# utility work on PPC machines (change from 'L'-encoding in pack to 'V') +# Version 0.2 +# Several patches included from Nathan Stratton Treadway(nathant@ontko.com) +# to adjust the platform output as well as fixes for other minor bugs +# Version 0.1 +# Initial release +# +# For information on El Torito see +# http://en.wikipedia.org/wiki/El_torito + +$vSecSize=512; +$secSize=2048; +$ret=undef;$version=undef;$opt_h=undef;$loadSegment=undef;$systemType=undef; + +# +# Read a particular sector from a file +# sector counting starts at 0, not 1 +# +sub getSector{ + my ($secNum, $secCount, $file)=@_; + my ($sec, $count); + + open(FILE, "<:raw", $file) || die "Cannot open \"$file\" \n"; + + seek(FILE, $secNum*$secSize, 0); + $count=read(FILE, $sec, $vSecSize*$secCount, 0) ; + if( $count != $vSecSize*$secCount ){ + warn "Error reading from file \"$file\"\n"; + } + close(FILE); + + return($sec); +} + + +# +# Write eltorito data into a file +# +sub writeOutputFile{ + my($name)=shift; + my($value)=shift; + + open(OUT, ">:raw", $name)|| die "$0: Cannot open outputfile \"$name\" for writing. Stop."; + print OUT $value; + close(OUT); +} + + +# +# Usage +# +sub usage{ + warn "\n$0 [-hv] [-o outputfilename] cd-image \n", + "Script will try to extract an El Torito image from a \n", + "bootable CD (or cd-image) given by <cd-image> and write \n", + "the data extracted to STDOUT or to a file.\n", + " -h: This help. \n", + " -v: Print version of script and exit.\n", + " -o <file>: Write extracted data to file <file> instead of STDOUT.\n", + "\n\n"; + exit 0; +} + + +# --------------------------------------------------------------------- +$ret=getopts('hvo:'); + +if( defined($opt_v) ){ + warn "Version: $utilVersion \n"; + exit 0; +} + +if( defined($opt_h) || $#ARGV <0 ){ + usage(0); +} + +if( defined($opt_o) ){ + $outputFilename="$opt_o"; +} + +$imageFile=$ARGV[0]; + +if( ! -r $imageFile ){ + die "Cannot read image/device \"$imageFile\". Aborting\n"; +} + +# +# Read Sector 17 from CD which should contain a Boot Record Volume +# descriptor. This descriptor contains at its start the text ($isoIdent) +# CD001 and ($toritoSpec) +# EL TORITO SPECIFICATION +# see http://www.cdpage.com/Compact_Disc_Variations/eltoritoi.html +# for details +# + +$sector=getSector(17, 1, $imageFile ); +($boot, $isoIdent, $version, $toritoSpec, + $unUsed, $bootP)= unpack( "Ca5CA32A32V", $sector ); + +if( $isoIdent ne "CD001" || $toritoSpec ne "EL TORITO SPECIFICATION" ){ + die "This data image does not seem to be a bootable CD-image\n"; +} + +# +# Now fetch the sector of the booting catalog +# +$sector=getSector($bootP, 1, $imageFile ); + +print STDERR "Booting catalog starts at sector: $bootP \n"; + +# The first 32 bytes of this sector contains the validation entry for a +# boot. The first byte has to be 01, the next byte determines the +# architecture the image is designed for, where 00 is i86, 01 is PowerPC +# and 02 is Mac. More data give info about manufacturer, etc. The +# final two bytes must contain 0x55 and 0xAA respectively (as +# defined by the El Torito standard). + +$validateEntry=substr($sector, 0, 32); + +($header, $platform, $unUsed, $manufact, $unUsed, $five, $aa)= + unpack( "CCvA24vCC", $validateEntry); + +if( $header != 1 || $five != 0x55 || $aa != 0xaa ){ + die "Invalid Validation Entry on image \n"; +} + +print STDERR "Manufacturer of CD: $manufact\n"; +print STDERR "Image architecture: "; +print STDERR "x86" if( $platform == 0 ); +print STDERR "PowerPC" if( $platform == 1 ); +print STDERR "Mac" if( $platform == 2 ); +print STDERR "unknown ($platform)" if( $platform > 2 ); +print STDERR "\n"; + +# +# Now we examine the initial/defaultentry which follows the validate +# entry and has a size of 32 bytes. + +$initialEntry=substr($sector, 32, 32); + +($boot, $media, $loadSegment, $systemType, $unUsed, + $sCount, $imgStart, $unUsed)=unpack( "CCvCCvVC", $initialEntry); + +if( $boot != 0x88 ){ + die "Boot indicator in Initial/Default-Entry is not 0x88. CD is not bootable. \n"; +} + +print STDERR "Boot media type is: "; +if( $media == 0 ){ + print STDERR "no emulation"; + $count=0; +} +if( $media == 1 ){ + print STDERR "1.2meg floppy"; + $count=1200*1024/$vSecSize; +} +if( $media == 2 ){ + print STDERR "1.44meg floppy"; + $count=1440*1024/$vSecSize; +} +if( $media == 3 ){ + print STDERR "2.88meg floppy"; + $count=2880*1024/$vSecSize; +} +if( $media == 4 ){ + print STDERR "harddisk"; + $MBR=getSector($imgStart, 1, $imageFile ); + $partition1=substr($MBR, 446, 16); + ($unUsed, $firstSector, $partitionSize) = unpack( "A8VV", $partition1); + $count=$firstSector + $partitionSize; +} +print STDERR "\n"; + +# Only use the internal sector counter if the real size is unknown +# ($count==0) +$cnt=$count==0?$sCount:$count; + +print STDERR "El Torito image starts at sector $imgStart and has $cnt sector(s) of $vSecSize Bytes\n"; + +# We are there: +# Now read the bootimage to stdout +$image=getSector($imgStart, $cnt, $imageFile); + +if( length($outputFilename) ){ + writeOutputFile($outputFilename, $image); + print STDERR "\nImage has been written to file \"$outputFilename\".\n"; +}else{ + print "$image"; + print STDERR "Image has been written to stdout ....\n"; +} |