On Thu, Mar 4, 2010 at 12:26 PM, Michael McElroy <
address@hidden> wrote:
> Hi Dave,
>
> I having been fooling around with fakeroot today. It's strange. If I kick
> off a shell in fakeroot, I can create the nodes and archive them. The
> results in the real filesystem will be files. The fakeroot man page advises
> against building binaries under it. I'll look at the crossplex files and see
> what I can do.
>
> Here's an example:
>
> cd ~/testfiles; fakeroot -- /bin/bash -c "mknod xxx c 1 2;tar cf
> /home/mike/test.tar ."
>
> or
>
> cd ~/testfiles; fakeroot -- /bin/bash -c "/bin/bash cmdlist;tar cf
> /home/mike/test.tar ."
>
>
> Mike
>
>
> On Thu, Mar 4, 2010 at 2:53 PM, David Wuertele <
address@hidden> wrote:
>>
>> On Thu, Mar 4, 2010 at 9:43 AM, Michael McElroy <
address@hidden>
>> wrote:
>> > I built the example on my Ubuntu system. The build stopped and asked for
>> > a
>> > password with making device nodes. OK, I can fix that on my home system
>> > but
>> > at work, can't do it. My work system just terminates the build when
>> > trying
>> > to run mknod. I've read about using a chroot jail or a utility called
>> > makedev. How do other people handle this.
>>
>> I don't believe the kernel will allow device node creation by a
>> non-root user even in a chroot jail. The problem is that if you can
>> create your own device, you can create it with any permissions you
>> want, and that gives a way to bypass normal device permissions.
>> However, you may be able to fake the creation of a device node. I
>> believe the fakeroot program could work for this, but I haven't tried
>> it yet. It will take some experimentation to integrate fakeroot with
>> crossplex, but that is on my to-do list. One issue is that any
>> command that expects to find the device node must be run in the
>> fakeroot environment.
>>
>> If you have time to experiment, you could install fakeroot, and run
>> the crossplex make inside of fakeroot. Crossplex will still try to
>> use "sudo" unless you remove it. You can easily remove it by editing
>> lines 103-112 in crossplex-0.10.0/lib/
targetfs.mk.
>>
>> If someone can show me how to actually create real devices like "sudo
>> mknod -m 600 console c 5 1" without the sudo, I will change crossplex
>> to do it that way.
>>
>> I know that at least for the construction of initramfs filesystems
>> built into the Linux kernel, it is possible to create a device
>> description without creating the devices themselves. I might add that
>> functionality to crossplex as an optimization. However, this does not
>> solve the problem of creating nodes on the local host for export as an
>> NFS filesystem, or other deployment modes that don't have the
>> meta-device option.
>>
>> Dave
>
>
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