[OpenIndiana-discuss] Recreate /dev/null

[Martin Bochnig]

On Thu, Apr 25, 2013 at 2:53 PM, James Carlson <carlsonj at workingcode.com>wrote:

> On 04/25/13 08:03, Richard Jones wrote:
> > On Thu, Apr 25, 2013 at 01:30:35PM +0200, Jim Klimov wrote:
> >> How about removing both /devices/pseudo/mm at null* and /dev/null and
> >> then trying devfsadm?
> >
> > # rm /dev/null
> > rm: cannot remove `/dev/null': No such file or directory
> > # rm /devices/pseudo/mm at 0:null
> > rm: cannot remove `/devices/pseudo/mm at 0:null': Operation not applicable
> > # devfsadm
> > devfsadm: cannot create link: /dev/null -> ../devices/pseudo/mm at 0:null.
> > max attempts exceeded
>
> You can't manually whack things in /dev or /devices, because those
> things don't exist in a disk-based file system, in exactly the same way
> that the contents of /proc is purely a fiction in memory.  See dev(7FS),
> devfs(7FS) and proc(4) for the gory details of those.  There are others
> of these ilk around, such as objfs(7FS), which mounts on /system/object,
> ctfs(7FS) on /system/contract, and mnttab(4) on /etc/mnttab.  (No, I
> can't readily explain why the man pages are scattered like that.  :-/)
>
> Things are not as they were ages ago, when /dev and /devices were actual
> directories on disk with real files in them that had to be periodically
> maintained (sometimes with the "reconfiguration reboot" which is
> similarly gone).  This all changed with PSARC/2003/246 "Filesystem
> Driven Device Naming".  (As a side note, this means that due to that
> project, if you once had a habit of doing something like "ln -s cua/a
> mymodem", that simply does not work following the introduction of that
> project; you can't write to a file system that doesn't exist.)
>
> If the contents of /dev or /devices is wrong, then it means that the
> information backing the devfs driver is bad.  Part of this information
> is kept in /etc/devices/, at least for dynamic devices (e.g., SCSI
> disks).  But that's not how a pseudo (virtual) device like /dev/null is
> populated.
>
> Unfortunately, that's where my knowledge of the system (based on my
> years in PSARC) ends.  I don't know how to repair damage like you're
> describing.  I just know that the people telling you to "rm" these fake
> files or run mknod are misinformed.  That'll never work.




It will, if you actually manipulate the boot_archive itself.
At least when speaking of the boot_archive of LiveMedia.
All the later fake stuff depends on a well defined skeleton to be present
_before_ it gets virtual.
Otherwise these services fail and you cannot boot very far.



Martin Bochnig
SCSA Sol8, SCSA Sol9
SCNA Sol8, SCNA Sol9
SCSecA Sol9