Creating RAM disks as a non root user.

Creating RAM disks as a non root user.

[Rod Boyce]

All,

I've got to create a RAM disk for our new system.  I've found this little
utility called genext2fs the web site is
http://sourceforge.net/projects/genext2fs/
<http://sourceforge.net/projects/genext2fs/>  but my question.
What do other people use to do this? Why should I have to become the root
user just to create a RAM disk I can do everything else without becoming
root on my development machine.  I would like to be able to make this next
step as well.


Regards,
Rod Boyce.


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RE: Creating RAM disks as a non root user.

[James Don]

I think in DENX new ELDK they may use what you just found ... but in older
versions of SELF you must become root user like you say ...

Jim

-----Original Message-----
From: Rod Boyce [mailto:rod_boyce@stratexnet.com]
Sent: Monday, February 03, 2003 9:01 PM
To: 'linuxppc-embedded@lists.linuxppc.org'
Subject: Creating RAM disks as a non root user.


All,

I've got to create a RAM disk for our new system.  I've found this little
utility called genext2fs the web site is
http://sourceforge.net/projects/genext2fs/
<http://sourceforge.net/projects/genext2fs/>  but my question.
What do other people use to do this? Why should I have to become the root
user just to create a RAM disk I can do everything else without becoming
root on my development machine.  I would like to be able to make this next
step as well.


Regards,
Rod Boyce.


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Creating RAM disks as a non root user.

[Wolfgang Denk]

In message <8D7C5F56B409554D9D46AC22195807F3061C5B@exchwenz01.dmcwave.co.nz> you wrote:
>
> I've got to create a RAM disk for our new system.  I've found this little
> utility called genext2fs the web site is
> http://sourceforge.net/projects/genext2fs/
> <http://sourceforge.net/projects/genext2fs/>  but my question.
> What do other people use to do this? Why should I have to become the root

Our ELDK uses genext2fs, too.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Landru! Guide us!
	-- A Beta 3-oid, "The Return of the Archons", stardate 3157.4

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RE: Creating RAM disks as a non root user.

[Kerl, John]

For me, this is the only step at which I need to be root.
If there's a way around it, I haven't bothered to find it.

-----Original Message-----
From: Rod Boyce [mailto:rod_boyce@stratexnet.com]
Sent: Monday, February 03, 2003 7:01 PM
To: 'linuxppc-embedded@lists.linuxppc.org'
Subject: Creating RAM disks as a non root user.



All,

I've got to create a RAM disk for our new system.  I've found this little
utility called genext2fs the web site is
http://sourceforge.net/projects/genext2fs/
<http://sourceforge.net/projects/genext2fs/>  but my question.
What do other people use to do this? Why should I have to become the root
user just to create a RAM disk I can do everything else without becoming
root on my development machine.  I would like to be able to make this next
step as well.


Regards,
Rod Boyce.


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RE: Creating RAM disks as a non root user.

[Jean-Denis Boyer]

Here is the recipe we use to mount ramdisk images without being a root user.

First, there must be an entry (one per user) in /etc/fstab, like the following:

 /home/jdboyer/initrd_lnk /home/jdboyer/mnt auto noauto,loop,user,rw 0 0

where 'initrd_lnk' is a soft-link to the file to mount through the loop device,
and 'mnt' is the mount point. These informations can NOT be modified by the user.

Note that the option 'user' in fstab allows any user to mount/unmount this specific entry.

Then, we can mount a ramdisk image that is located anywhere,
by first modifying the soft link, and then mounting 'mnt'.
You can either create new ramdisk images, or mount already existing ones (very useful!).

Regards,
--------------------------------------------
 Jean-Denis Boyer, B.Eng., Technical Leader
 Mediatrix Telecom Inc.
 4229 Garlock Street
 Sherbrooke (Québec)
 J1L 2C8  CANADA
 (819)829-8749 x241
--------------------------------------------

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Re: Creating RAM disks as a non root user.

[Wolfgang Denk]

In message <2702075D4DE2B043BF5EB82E9CFAD45B093BBB@mail1.mediatrix.com> you wrote:
>
> Here is the recipe we use to mount ramdisk images without being a root user.
...
> Note that the option 'user' in fstab allows any user to mount/unmount this specific entry.

Just _mounting_ ramdisk images is not the problem...

> You can either create new ramdisk images, or mount already existing ones (very useful!).

...but to create a useful ramdisk image you will usually also have to
create the device nodes in the /dev directory. And this is  something
that  really  _requires_ root permissions (or it would otherwise open
huge security issues).


And from the system administrator's point of view allowing anybody to
mount any images he likes is a serious security issue, too.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
"If the code and  the  comments  disagree,  then  both  are  probably
wrong."                                                - Norm Schryer

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Re: Creating RAM disks as a non root user.

[Kenneth Johansson]

On Tue, 2003-02-04 at 22:52, Wolfgang Denk wrote:
>
> In message <2702075D4DE2B043BF5EB82E9CFAD45B093BBB@mail1.mediatrix.com> you wrote:
> >
> > Here is the recipe we use to mount ramdisk images without being a root user.
> ...
> > Note that the option 'user' in fstab allows any user to mount/unmount this specific entry.
>
> Just _mounting_ ramdisk images is not the problem...
>
> > You can either create new ramdisk images, or mount already existing ones (very useful!).
>
> ...but to create a useful ramdisk image you will usually also have to
> create the device nodes in the /dev directory. And this is  something
> that  really  _requires_ root permissions (or it would otherwise open
> huge security issues).
>

If you want full control over owner and group on a file by file basis
you can run fakeroot while creating the image/tar or whatever.

I don't know if fakeroot exist anywhere else than in debian but it
should not be hard to port.

--
Kenneth Johansson
Ericsson AB                       Tel: +46 8 404 71 83
Tellusborgsvägen  94              Fax: +46 8 404 72 72
126 25 Stockholm                  ken@switchboard.ericsson.se


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