/var/tmp shown as separate file system if PrivateTmp is enabled on systemd

[ahaaje]

systemd has an option PrivateTmp=yes that will cause apache mod_php or php-fpm to mount /tmp and/or /var/tmp as it's own private mount, for security reasons.

This causes /var/tmp to show up as mounted as a separate file system with the same properties as the file system where it is mounted (normally /).

So you could get a list of mounts like this in the browser

/ 100GB ext4
/var/tmp 100GB ext4

From the CLI we would not get the second line.

I think we should not list the private temp dir if we can safely detect that it is actually PrivateTmp=yes that is in force.

This command will show if it is enabled for apache

systemctl show apache2 | grep PrivateTmp
PrivateTmp=yes