[PATCH][BZ 19108] paths: use /proc/mounts instead of mtab

[Florian Weimer]

On 12/11/2015 02:03 PM, Jason A. Donenfeld wrote:
> I'm not really part of their camp, but the systemd people write this
> in their release notes:
> 
> https://github.com/systemd/systemd/blob/master/NEWS
> 
>> Any reference to /etc/mtab has been dropped from
>> systemd. The file has been obsolete since a while, but
>> systemd refused to work on systems where it was incorrectly
>> set up (it should be a symlink or non-existent). Please make
>> sure to update to util-linux 2.27.1 or newer in conjunction
>> with this systemd release, which also drops any reference to
>> /etc/mtab. If you maintain a distribution make sure that no
>> software you package still references it, as this is a
>> likely source of bugs. There's also a glibc bug pending,
>> asking for removal of any reference to this obsolete file:
>> https://sourceware.org/bugzilla/show_bug.cgi?id=19108

/etc/mtab is part of the ABI, so I don't think the above can be quite right.

In fact, I would rather prefer if glibc keeps using /etc/mtab, as a
reminder that you can't possibly remove the file without breaking
backwards compatibility.  Yes, the separately maintained list of mounts
in /etc/mtab (as a regular file) is obsolete, but that does not mean you
can remove the file, you need to keep the compatibility symbolic link.

Florian