Re: mount error message

[Dylan Cali <calid1984@gmail.com>]

Karel Zak <kzak@...> writes:

> 
> On Sun, Sep 07, 2014 at 01:19:05PM -0500, Bruce Dubbs wrote:
> > I have a user that complains that mount is giving an incorrect error message
> > under some circumstances.  For instance if mtab is symlinked to
> > /proc/self/mounts the command and /run is not in fstab:
> > 
> > $ mount /run
> > 
> > returns an error message:
> > 
> >   mount: /run: No such file or directory
> > 
> > However if mtab is a regular file, the error message is:
> > 
> >   mount: can't find /run in /etc/fstab
> 
> $ test -d /mnt/test && echo "yes" || echo "no"
> yes
> $ test -d /nothing && echo "yes" || echo "no"
> no
> 
> $ ls -l  /etc/mtab 
> lrwxrwxrwx 1 root root 12 Jun 17 15:42 /etc/mtab -> /proc/mounts
> 
> $ mount /mnt/test
> mount: can't find /mnt/test in /etc/fstab
> 
> $ mount /nothing
> mount: /nothing: No such file or directory
> 
> $ ls -l  /etc/mtab 
> -r--r--r-- 1 root root 2693 Sep 10 10:16 /etc/mtab
> 
> $ mount /mnt/test
> mount: can't find /mnt/test in /etc/fstab
> $ mount /nothing 
> mount: /nothing: No such file or directory
> 
> All works as expected.
> 
> Note that mount(8) sanitize paths specified by non-root users on
> command line, so the message "No such file or directory" is really
> expected and it's far before libmount starts to evaluate things in
> mtab/fstab.
> 
>     Karel
> 

Hello I'm the user in question.  The specific situation was a boot time
failure where /proc had failed to mount.  So to enumerate the conditions and
the result:

1) /proc is not mounted (or has failed to mount)
2) /etc/mtab is a symlink to /proc/mounts (or /proc/self/mounts)
3) /run is not in /etc/fstab
4) The directory /run exists on the filesystem

In this situation 'mount /run' results in: 
mount: /run: mount failed: No such file or directory

Obviously mount is referring to /etc/mtab not existing, so the error message
at present is misleading.