WIM header structure

[joakim]

I am working on a patch for bootmgr that may boot any image inside of boot.wim.

For the wim format specialists of this forum;

How can we retrieve these fields, as specified in the wim header, from any image contained in boot.wim;

rhOffsetTable
rhXmlData
rhBootMetadata

It is basically size and offset for each of the 3 resources.

I had a quick look at the documentation for wimgapi.dll, but have my doubts that wimgapi.dll is capable of retrieving this information.

These values are going to be patched into the wim header as read into memory by bootmgr..

Joakim

[jaclaz]

It is basically size and offset for each of the 3 resources.

Some info can be gathered by ImageX:

http://apcmag.com/exploring_vistas_wim_format_with_imagex.htm

As often happens info on MS is to say the least incomplete:

http://technet.microsoft.com/en-us/library/cc749478(WS.10).aspx?ITPID=win7dtp

but this one is not too bad :

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=184706a3-6e05-4d9d-a034-830f4290ee42&DisplayLang=en

http://download.microsoft.com/download/f/e/f/fefdc36e-392d-4678-9e4e-771ffa2692ab/Windows%20Imaging%20File%20Format.rtf

7-zip source code could be another place to look for.

These may also help (or completely fail to):

http://www.codeproject.com/KB/vista/wimgapi.aspx

http://www.wincert.net/forum/index.php?/topic/6297-guide-wimgapi-in-vb-net/

http://www.petri.co.il/image-based-installations-with-windows-imaging-format.htm

jaclaz

[joakim]

None of those documents/tools can get this information. Imagex.exe/wimgapi.dll will show you some basic information about the wim, except for those 3 fields as specified in the first post. The wim format document will tell you what is what for the individual parts, but has omitted to explain anything about those 3 header fields.

That said, imagex.exe is surely capable of retrieving this piece of information from somewhere. But from where?

I suspect we need to create something on our own to get this information, or completely disassemble wimgapi.dll... I will keep on digging, but could need some help..

Btw, these 3 fields are the only parts in the header that needs to be patched, to boot another image.

Joakim

[CoffeeFiend]

Check the patent applications like this. That along with 7-zip's source should pretty much cover it all. Look into \CPP\7zip\Archive\Wim. Feel free to even run it inside Visual Studio and single-step through the relevant parts of the WIM-reading code.

[joakim]

OK, looks like I need to study some more, and realistically not having it decoded in a short time (if ever).

Joakim