Re: devlinks: an alternative to devfs

Kevin Lentin (kevinl@cs.monash.edu.au)
Thu, 8 Jan 1998 18:11:57 +1100

On Thu, Jan 08, 1998 at 12:08:09PM +1100, Richard Gooch wrote:
> Er, but then GNU tar can't back up /dev properly, because it doesn't
> know about the magic bit. When you restore your FS those entries
> become ordinary symlinks.

But are _any_ of the permission bits on a symlink used? Just set the
sticky bit on the symlink. tar should handle that shouldn't it?

Urrgghhh. I thought if I did it via libc I could fiddle the permissions on
the symlink. But you can't. It either modifies the destination file or
gives you ENOENT if the symlink points to nowhere. I thought it might
modify the symlink if it pointed nowhere.

So we need filesystem support again. AARRGGHH.

> Removing the entry if it doesn't exist is fine: the internal table
> will just mark the entries for /gaol/dev as verboten for that
> superblock.

That's probably the best solution. Although you'd want a way to undo that.
eg if I happen do rm /dev/lp for some reason and then later unload and
reload the module, I might want lp to turn up again. Or I might not in the
case of /gaol/dev. So you'd need a way of undoing that marker.

-- 
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