Re: /proc/misc has bad mode
Lex Spoon (sspoon@clemson.edu)
Tue, 23 Apr 1996 23:19:02 -0400 (EDT)
Andreas Jaeger wrote:
>
>
> Matthias Urlichs <smurf@smurf.noris.de> writes:
>
> >
> > ?r--r--r-- 1 root system 0 Apr 19 22:33 /proc/misc
>
> > NB, I just ripped out all the write-to-mtab handling out of mount and
> > umount, and replaced /etc/mtab with a symlink to /proc/mounts.
> > Nice. Now I only have to tell ssh to forget about /etc/ssh_random_seed
> > (there's /dev/random, right?), and I can keep my whole root disk readonly,
> > which is a Good Thing as it significantly speeds up booting after one of
> > those nasty crashes (Shit Happens, occasionally, when you're developing
> > drivers). Of course, /var is on a different partition, /tmp is a symlink to
> > /var/tmp, /home is on NFS, and /usr has been readonly for ages. ;-)
>
> But what are you doing with /dev? I need to mount /dev read-write to
> change e.g. on login the permissions on /dev/tty*. And I fear I cannot
> put /dev on a different partition, can I (I think I need /dev to mount
> other partitions and if I don't have /dev ... :-( )?
> The only possibility that I can see for a read-only root file-system
> is making my /dev/tty* links to another partition.
>
> Andreas
>
Can a device file be opened O_RDWR on a read-only fs?
If so, you could have a /boot/dev with device files needed for
mounting, accessible only to root. The normal device files could
then live on a different partition, say in /var/dev.
When the bootup scripts start, they could do
rm -f /dev
ln -s /boot/dev /dev
After everything is mounted, they could do
rm -f /dev
ln -s /var/dev /dev
Lex