Some hfsplus questions

Some hfsplus questions

[Andrey Vul]

I have some questions about hfsplus:
1) Is there a / how do you patch the fs driver / mount options to
allow starting from an offset (f.e. certain DMG files' HFS+ superblock
start at 32768)?
2) Is there a / how do you patch the fs driver to allow for
transparent zlib decompression of the HFS+ volume (inside the DMG
file)? I lack the kernel skills to reverse-engineer Darwin and create
a kernel patch of a FUSE module.
-- 
Andrey Vul

Re: Some hfsplus questions

[Bob Copeland]

On Thu, Sep 18, 2008 at 9:55 PM, Andrey Vul <andrey.vul@gmail.com> wrote:
> I have some questions about hfsplus:
> 1) Is there a / how do you patch the fs driver / mount options to
> allow starting from an offset (f.e. certain DMG files' HFS+ superblock
> start at 32768)?

In general you do this with losetup(8) instead of in the filesystem itself,
since the FS generally doesn't care about the block device.

e.g. losetup -o 32768 ....

> 2) Is there a / how do you patch the fs driver to allow for
> transparent zlib decompression of the HFS+ volume (inside the DMG
> file)?

No idea.  A device mapper target (or fuse-over-loopback) could do that but
I don't know if there is something suitable already.

-- 
Bob Copeland %% www.bobcopeland.com