[Qemu-devel] How to extract content of a raw image on host?

[Qemu-devel] How to extract content of a raw image on host?

[Dirk Behme]

Hi,

is there a way to extract the contents of a qemu raw image on (x86 
Linux) host without starting QEMU itself? If so, any hint would be 
quite nice.

I'm looking for anything like the reverse what

http://lists.gnu.org/archive/html/qemu-devel/2006-04/msg00448.html

seems to do. Extract files/directories from an existing raw image.

qemu-img reports me

 > qemu-img info disk.img
image: disk.img
file format: raw
virtual size: 4.3M (4515328 bytes)
disk size: 4.3M

but what is in it and how to access the content?

Thanks, and sorry if this is a FAQ and I missed the correct search string,

Dirk

Re: [Qemu-devel] How to extract content of a raw image on host?

[JonY]

Dirk Behme wrote:
> Hi,
> 
> is there a way to extract the contents of a qemu raw image on (x86 
> Linux) host without starting QEMU itself? If so, any hint would be quite 
> nice.
> 
> I'm looking for anything like the reverse what
> 
> http://lists.gnu.org/archive/html/qemu-devel/2006-04/msg00448.html
> 
> seems to do. Extract files/directories from an existing raw image.
> 
> qemu-img reports me
> 
>  > qemu-img info disk.img
> image: disk.img
> file format: raw
> virtual size: 4.3M (4515328 bytes)
> disk size: 4.3M
> 
> but what is in it and how to access the content?
> 
> Thanks, and sorry if this is a FAQ and I missed the correct search string,
> 
> Dirk
> 
> 
> 

Hi,

have you tried using a loop back mount?

Re: [Qemu-devel] How to extract content of a raw image on host?

[Dirk Behme]

JonY wrote:
> Dirk Behme wrote:
> 
>> Hi,
>>
>> is there a way to extract the contents of a qemu raw image on (x86 
>> Linux) host without starting QEMU itself? If so, any hint would be 
>> quite nice.
>>
>> I'm looking for anything like the reverse what
>>
>> http://lists.gnu.org/archive/html/qemu-devel/2006-04/msg00448.html
>>
>> seems to do. Extract files/directories from an existing raw image.
>>
>> qemu-img reports me
>>
>>  > qemu-img info disk.img
>> image: disk.img
>> file format: raw
>> virtual size: 4.3M (4515328 bytes)
>> disk size: 4.3M
>>
>> but what is in it and how to access the content?
>>
>> Thanks, and sorry if this is a FAQ and I missed the correct search 
>> string,
>>
>> Dirk
>>
> Hi,
> 
> have you tried using a loop back mount?

# mount -o loop disk.img mnt/
mount: You have to specify a file system type
# mount -t raw -o loop disk.img mnt/
mount: unknown file system type „raw“

Sorry if I miss the obvious ;)

Dirk

Re: [Qemu-devel] How to extract content of a raw image on host?

[JonY]

Dirk Behme wrote:
> JonY wrote:
>> Dirk Behme wrote:
>>
>>> Hi,
>>>
>>> is there a way to extract the contents of a qemu raw image on (x86 
>>> Linux) host without starting QEMU itself? If so, any hint would be 
>>> quite nice.
>>>
>>> I'm looking for anything like the reverse what
>>>
>>> http://lists.gnu.org/archive/html/qemu-devel/2006-04/msg00448.html
>>>
>>> seems to do. Extract files/directories from an existing raw image.
>>>
>>> qemu-img reports me
>>>
>>>  > qemu-img info disk.img
>>> image: disk.img
>>> file format: raw
>>> virtual size: 4.3M (4515328 bytes)
>>> disk size: 4.3M
>>>
>>> but what is in it and how to access the content?
>>>
>>> Thanks, and sorry if this is a FAQ and I missed the correct search 
>>> string,
>>>
>>> Dirk
>>>
>> Hi,
>>
>> have you tried using a loop back mount?
> 
> # mount -o loop disk.img mnt/
> mount: You have to specify a file system type
> # mount -t raw -o loop disk.img mnt/
> mount: unknown file system type „raw“
> 
> Sorry if I miss the obvious ;)
> 
> Dirk
> 
> 
Hi,

"raw" is not really a file system, its just a way of saying the image 
has a "exact copy of every bit" of what a physical disk would have.

Try, "mount -o loop disk.img mnt/", mount might be able to determine the 
correct file system.

If it is a hard disk image with partition tables, try opening it with 
fdisk to confirm so. List down the partitions. Note the offsets

Try something like "mount -o loop,offset=32256 disk.img mnt/"

see here for more details:
http://howto.wikia.com/wiki/How_to_see_the_content_of_a_Qemu_image_on_a_linux-based_OS

Re: [Qemu-devel] How to extract content of a raw image on host?

[JonY]

JonY wrote:
>
> 
> Try, "mount -o loop disk.img mnt/", mount might be able to determine the 
> correct file system.
> 

Oops, I didn't read your message thoroughly, sorry. I've never really 
need to specify the type of file system for mount, not sure what happened.

Re: [Qemu-devel] How to extract content of a raw image on host?

[Laurent Vivier]

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Le samedi 16 février 2008 à 08:18 +0100, Dirk Behme a écrit :
> JonY wrote:
> > Dirk Behme wrote:
> > 
> >> Hi,
> >>
> >> is there a way to extract the contents of a qemu raw image on (x86 
> >> Linux) host without starting QEMU itself? If so, any hint would be 
> >> quite nice.
> >>
> >> I'm looking for anything like the reverse what
> >>
> >> http://lists.gnu.org/archive/html/qemu-devel/2006-04/msg00448.html
> >>
> >> seems to do. Extract files/directories from an existing raw image.
> >>
> >> qemu-img reports me
> >>
> >>  > qemu-img info disk.img
> >> image: disk.img
> >> file format: raw
> >> virtual size: 4.3M (4515328 bytes)
> >> disk size: 4.3M
> >>
> >> but what is in it and how to access the content?
> >>
> >> Thanks, and sorry if this is a FAQ and I missed the correct search 
> >> string,
> >>
> >> Dirk
> >>
> > Hi,
> > 
> > have you tried using a loop back mount?
> 
> # mount -o loop disk.img mnt/
> mount: You have to specify a file system type
> # mount -t raw -o loop disk.img mnt/
> mount: unknown file system type „raw“
> 
> Sorry if I miss the obvious ;)

Loop is not able to manage partition.
Either you use the offset option to point to the offset of the partition
you want to mount in the raw image.
Either you use the attached patch to be able to manage partition table
with loop (and load the module with parameter "max_part=64")

Laurent
-- 
----------------- Laurent.Vivier@bull.net  ------------------
"Programmers who subconsciously view themselves as artists
 will enjoy what they do and will do it better." D. Knuth

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Re: [Qemu-devel] How to extract content of a raw image on host?

[Stuart Brady]

On Sat, Feb 16, 2008 at 08:55:06AM +0100, Laurent Vivier wrote:
> Loop is not able to manage partition.

You could use kpartx (from util-linux), which will create device nodes 
for each partition.

Cheers,
-- 
Stuart Brady