legacy/libisoburn/trunk/xorriso/README

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     libburnia-project.org     scdbackup.sourceforge.net/xorriso_eng.html
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xorriso. By Thomas Schmitt <scdbackup@gmx.net>
Integrated sub project of libburnia-project.org but also published via:
http://scdbackup.sourceforge.net/xorriso_eng.html
http://scdbackup.sourceforge.net/xorriso-0.2.7.tar.gz
Copyright (C) 2006-2008 Thomas Schmitt, provided under GPL version 2.
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xorriso is a program which maps file objects from POSIX compliant
filesystems into Rock Ridge enhanced ISO 9660 filesystems and allows
session-wise manipulation of such filesystems. It can load the management
information of existing ISO images and it writes the session results to
optical media or to filesystem objects.
Vice versa xorriso is able to restore file objects from ISO 9660 filesystems.

Currently it is only supported on Linux with kernels >= 2.4.

A special property of xorriso is that it needs neither an external ISO 9660
formatter program nor an external burn program for CD or DVD but rather
incorporates the libraries of libburnia-project.org .

By using this software you agree to the disclaimer at the end of this text:
"... without even the implied warranty ..."


                   Compilation, First Glimpse, Installation

The most simple way to get xorriso from source code is the xorriso standalone
tarball.

Prerequisites:
The tarball contains anything that is needed except libc and libpthread.
libreadline and the readline-dev headers will make dialog mode more convenient,
but are not mandatory.

Obtain xorriso-0.2.7.tar.gz, take it to a directory of your choice and do:

    tar xzf xorriso-0.2.7.tar.gz
    cd xorriso-0.2.7

Within that directory execute:

    ./configure --prefix=/usr
    make

This will produce a binary named
    ./xorriso/xorriso

which you may strip to reduce it in size
    strip ./xorriso/xorriso

You may copy or move it to a directory where it can be found by the shell,
you may execute xorriso at the place where it was built, or you may execute
as superuser:
    make install

For general concepts, options and usage examples see
    man 1 xorriso

This man page is part of the tarball as
    xorriso/xorriso.1
You may get a first glimpse by
    man ./xorriso/xorriso.1

It gets installed with "make install" but may also be placed manually in the
./man1 directory below one of the directories mentioned in environment
variable $MANPATH.

The installation creates several alias links pointing to the xorriso binary:
    xorrisofs  starts xorriso with -as mkisofs emulation already enabled
    xorrecord  starts xorriso with -as cdrecord emulation already enabled
    osirrox    starts with -osirrox image-to-disk copying already enabled


                       Drives and Disk File Objects 

The user of xorriso needs rw-permission for the CD burner device.
A list of rw-accessible drives can be obtained by

    xorriso -devices

CD devices which offer no rw-permission are invisible to normal users.
The superuser should be able to see any usable drive and then set the
permissions as needed.

The output of  xorriso -devices  might look like

0  -dev '/dev/sr0' rwrw-- :  'TSSTcorp' 'CDDVDW SH-S203B' 
1  -dev '/dev/hda' rwrw-- :  'HL-DT-ST' 'DVD-ROM GDR8162B' 

Full and insecure enabling of both for everybody would look like
    chmod a+rw /dev/sr0 /dev/hda
This is equivalent to the traditional setup chmod a+x,u+s cdrecord.

I strongly discourage to run xorriso with setuid root or via sudo !
It is not checked for the necessary degree of hacker safety.

Consider to put all authorized users into group "floppy", to chgrp the
device file to that group and to disallow w-access to others.


A possible source of problems are hald or other automounters. 
If you can spot a process "hald-addon-storage" with the address of
your desired drive, then consider to kill it.

If you cannot get rid of the automounter that easily, try whether it helps
to always load the drive tray manually before starting a write run of
xorriso. Wait until the drive light is off.
Better try to unmount an eventually mounted media before a write run.


Besides true optical drives, xorriso can also address disk files as input or
output drives. The addresses of the disk files have to be preceded by "stdio:".
Like:
    xorriso -dev stdio:/tmp/pseudo_drive ...more arguments...


                              Testing

We are quite sure that libisofs produces accurate representations of the disk
files. This opinion is founded on a lot of test burns and checks by a little
test program which compares files from the mounted image with the orignals
on disk. It uses the normal POSIX filesystem calls, i.e. no libburnia stuff.

This program is not installed systemwide but stays in the installation
directory of the xorriso tarball as  test/compare_file . Usually it is
run as -exec payload of a find command. It demands at least three arguments:
The path of the first file to compare, the prefix1 to be cut off from path
and the prefix2 which gets prepended afterwards to obtain the path of the
second file to compare.
As further argument there can be -no_ctime which suppresses the comparison
of ctime date stamps.
The exit value is 0 if no difference was detected, non-0 else.

Example: After
   xorriso ... -pathspecs on -add /=/original/dir -- -commit_eject all
   mount /media/dvd
   cd test
compare tree /media/dvd with tree /original/dir :
   find /original/dir -exec ./compare_file '{}' /original/dir /media/dvd ';' \
   | less
and vice versa:
   find /media/dvd -exec ./compare_file '{}' /media/dvd /original/dir ';' \
   | less


                             File Formats

Currently there is only one file format peculiar to xorriso : sector maps
which describe the valid and invalid blocks on a media or a disk copy of
a media. xorriso creates and reads these file with its option -check_media.

The file begins with 32 bytes of cleartext of which the last one is a
newline character. The first 25 say "xorriso sector bitmap v2 ", the
remaining six characters give the size of the info text as decimal number.
This number of bytes follows the first 32 and will not be interpreted
by xorriso. They are rather to inform a human reader about the media type
and its track layout.
After the info text there are two 4 byte signed integers, most significant
byte first. The first one, N, gives the number of bits in the following bitmap
and the second number S gives the number of 2 KiB blocks governed by a single
bit in the map. Then come the bits in form of 8-bit bytes.
Data block M is covered by bit B=M/S in the map, bit number B is stored in
byte B/8 as bit B%8. A valid readable data block has its bit set to 1.


                             libisoburn

xorriso is based on libisofs which does ISO 9600 filesystem aspects and on
libburn which does the input and output aspects. Parts of this foundation
are accessed via libisoburn, which is closely related to xorriso.

libisoburn provides two services:
- Encapsulation of coordination between libisofs and libburn.
- Emulation of ISO 9660 multi-session on overwriteable media
  or random access files.

The sourcecode of all three libraries is included in the xorriso standalone
tarball. It is compiled with xorriso and linked statically.
But you may as well get and install releases of libburn and libisofs, in order
to be able to install a release of libisoburn which produces libisoburn.so.1
and a matching dynamically linked xorriso binary.
This binary is leaner but depends on properly installed libraries of suitable
revision.

Dynamic library and compile time header requirements for libisoburn-0.2.7 :
- libburn.so.4  , version libburn-0.5.2 or higher
- libisofs.so.6 , version libisofs-0.6.8 or higher
libisoburn and xorriso will not start with libraries which are older than their
headers seen at compile time. So compile in the oldest possible installation
setup unless you have reason to enforce a newer bug fix level.

Standalone xorriso has less runtime dependencies and can be moved more freely.


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    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License version 2 as
    published by the Free Software Foundation.

    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

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Based on and sub project of:
libburnia-project.org
By Mario Danic           <mario.danic@gmail.com>,
   Vreixo Formoso        <metalpain2002@yahoo.es>
   Thomas Schmitt        <scdbackup@gmx.net>
Copyright (C) 2006-2008 Mario Danic, Vreixo Formoso, Thomas Schmitt.

libburnia-project.org is inspired by and in other components still containing
parts of old
Libburn. By Derek Foreman <derek@signalmarketing.com> and
            Ben Jansens <xor@orodu.net>
Copyright (C) 2002-2006  Derek Foreman and Ben Jansens