Re: [gentoo-dev] rfc: converting /etc/mtab to a symlink

[Rich Freeman]

On Mon, Oct 14, 2013 at 4:03 PM, David Leverton
<levertond@××××××××××.com> wrote:
> So to work around that limitation we insist that everyone change how their
> systems are set up, and still have to reintroduce mtab under a different
> name ("utab", hidden away under /run) because /proc/self/mounts *doesn't*
> contain everything that's supposed to be in mtab after all?

The whole design of /etc/mtab is broken.  It isn't a list of
everything that is mounted - it is a list of everything done by the
mount command (the command - not the system call).  The handbook even
has a line about having to manually populate it before running grub
since it is flat-out wrong when you're in a chroot.  There are lots of
things that can cause it to get out-of-sync.

Perhaps there are edge cases where the symlink isn't sufficient -
that's what this thread is all about.  However, I've never liked the
design of mtab.  It isn't surprising to me that distros are largely
ditching it.

>  /etc/resolv.conf

As Mike already pointed out, resolution is actually a userspace
function entirely (I'm not sure if I were designing things from
scratch that I'd put it in the C library, but...).

However, if you want to know the hostname, you should be calling uname
and not looking around for /etc/hostname or whatever.  The kernel will
tell you the truth as it applies to your process, not what you think
should be the truth based on what amounts to a logfile.

Rich