Re: [LUG] Reading DMG file on Debian?

["M. J. Everitt" <m.j.everitt@xxxxxxx>]

On 12/11/18 17:39, Simon Waters wrote:
> On Debian stable box. Linux version 4.9.0-8-amd64 
>
> Have a DMG file I would like to examine the contents of without buying a Mac or 
> anything too insane. I just want to see if one file is present, and if it is 
> extract it. 
>
> The DMG may even just be a proprietary installer to download the real software 
> given its small size, if it is I'll probably have to figure out how to run it, 
> or file the relevant URLs it downloads and repeat.
>
> Figure I ought to be able to use dmg2img or hfs or hfsplus, but failed 
> miserably.
>
> How do I access a DMG disk image on Linux? I have a Windows VM if it helps.
>
> Tried variations on:
>
>  mount -o loop -t hfs image.dmg /mnt/''somewhere''
>
> mount: wrong fs type, bad option, bad superblock on /dev/loop4,
>        missing codepage or helper program, or other error
>
> dmg2img gives me and img file, and "fdisk -lu" is convinced I have a "20M HFS/
> HFS+" in this image file 40 sectors in.
>
> dmesg mostly he says:
> hfs: can't find a HFS filesystem on dev loop4
>
> loop4 is the next free loopback device. So everything seems to understand it.
>
> Is it just too new for my kernel, or am I missing something basic?
>
>
>
>
> dmg2img -v test.dmg 
>
> dmg2img v1.6.5 (c) vu1tur (to@xxxxxxxxxxxxx)
>
> test.dmg --> test.img
>
> reading property list, 9216 bytes from address 7263637 ...
> partition 0: begin=203, size=430, decoded=284
> partition 1: begin=948, size=430, decoded=284
> partition 2: begin=1695, size=430, decoded=284
> partition 3: begin=2424, size=430, decoded=284
> partition 4: begin=3137, size=1737, decoded=1164
> partition 5: begin=5157, size=430, decoded=284
> partition 6: begin=5885, size=430, decoded=284
> partition 7: begin=6630, size=430, decoded=284
>
> decompressing:
> opening partition 0 ...         [2] 100.00%  ok
> opening partition 1 ...         [2] 100.00%  ok
> opening partition 2 ...         [2] 100.00%  ok
> opening partition 3 ...         [2] 100.00%  ok
> opening partition 4 ...        [24] 100.00%  ok
> opening partition 5 ...         [2] 100.00%  ok
> opening partition 6 ...         [2] 100.00%  ok
> opening partition 7 ...         [2] 100.00%  ok
>
> Archive successfully decompressed as test.img
>
> fdisk -lu test.img
> Disk test.img: 20 MiB, 20971520 bytes, 40960 sectors
> Units: sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disklabel type: gpt
> Disk identifier: REDACTED
>
> Device     Start   End Sectors Size Type
> test.img1     40 40919   40880  20M Apple HFS/HFS+
>
>
Quick google suggests:

https://eastmanreference.com/how-to-work-with-dmg-files-on-linux

TL;DR - hfs  hfsplus kernel modules, dmg2img but beware of GUID dmg files.

Good luck!

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