Extract original ISO from initrd.img file

[hai wu]

Is there a tool to auto-extract livecd/ISO file from initrd.img (which was
generated from livecd-iso-to-pxeboot command)?

[Alan Pevec]

On Thu, Apr 28, 2011 at 6:13 AM, hai wu <haiwu.us(a)gmail.com&gt; wrote:
>  Is there a tool to auto-extract livecd/ISO file from initrd.img
> (which was
>  generated from livecd-iso-to-pxeboot command)? 
-to-pxeboot appends gziped cpio archive with ISO file to the original
initrd cpio archive, so if you know original initrd size, you could
extract appendix using e.g. dd. In general case, tool is needed to
search for the end-of-cpio-archive marker ("TRAILER!!!") which is what
attached Richard's initrdsplitter.c is doing, Read comments for usage.

Alan

[Richard W.M. Jones]

On Thu, Apr 28, 2011 at 01:18:29PM +0200, Alan Pevec wrote:
>  On Thu, Apr 28, 2011 at 6:13 AM, hai wu <haiwu.us(a)gmail.com&gt;
> wrote:
>  > Is there a tool to auto-extract livecd/ISO file from initrd.img (which was
>  > generated from livecd-iso-to-pxeboot command)?
>  
>  -to-pxeboot appends gziped cpio archive with ISO file to the original
>  initrd cpio archive, so if you know original initrd size, you could
>  extract appendix using e.g. dd. In general case, tool is needed to
>  search for the end-of-cpio-archive marker ("TRAILER!!!") which is what
>  attached Richard's initrdsplitter.c is doing, Read comments for usage. 
As Alan says.

Even better is not to get into this situation, ie. save the ISO before
running livecd-iso-to-pxeboot ...

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://et.redhat.com/~rjones/virt-df/

[hai wu]

Thanks, this is working.

On Thu, Apr 28, 2011 at 6:18 AM, Alan Pevec <apevec(a)gmail.com&gt; wrote:

>  On Thu, Apr 28, 2011 at 6:13 AM, hai wu <haiwu.us(a)gmail.com&gt;
> wrote:
>  > Is there a tool to auto-extract livecd/ISO file from initrd.img (which
>  was
>  > generated from livecd-iso-to-pxeboot command)?
>
>  -to-pxeboot appends gziped cpio archive with ISO file to the original
>  initrd cpio archive, so if you know original initrd size, you could
>  extract appendix using e.g. dd. In general case, tool is needed to
>  search for the end-of-cpio-archive marker ("TRAILER!!!") which is what
>  attached Richard's initrdsplitter.c is doing, Read comments for usage.
>
>  Alan
>
>  --
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>