# RunFS - Linux compatibility layer



## jammied (Jan 11, 2022)

Hi

I am trying to get some apps to run under Linux compatibility layer. I have established I need access to a working /run directory for networking to work correctly for Linux software.

I have tried nullfs(5) mounting /var/run to /compat/debian/run

After investigation, I have found /var/run is simply not accessible within the Linux compatibility layer, making this nullfs(5) mount rather useless.

Any tips on where to go next?


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## SirDice (Jan 11, 2022)

On most linux distributions I've seen /run is a symlink to /var/run and is a memory filesystem, so mount a tmpfs(5) on /compat/debian/var/run.


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## jammied (Jan 25, 2022)

That makes sense, however, probably should have added some detail into my original post.

/var/run once in the Linux compatibility layer loses all the contents of the original /var/run leaving only: lock &  utmp folders.

However, if I run /bin/bash from this folder, I can still see the original /var/run contents until I cd into the /var/run directory.


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## ct85711 (Jan 31, 2022)

This looks to be standard mount functionality(standard as it works the same way on Linux and FreeBSD as a whole) from what you are describing...

To make sure it is clear on the exact steps.  You have a folder with some contents.  You mount something to that folder's point; all the old stuff not accessable/visable.  If that is true; then you just ran into the normal and intended functionality of mount.  This leaves out overlay fudgery.  Looking at nullfs's man page it only says it is a loopback fs/device and not a overlay fs.


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## jammied (Jan 31, 2022)

Regardless, even if I access the original /var/run in Linux compat layer, same issue, so it is not to do with nullfs. There seems if I am honest to be some kind of remount of /var/run when I go into Linux compat that I haven't found documentation yet relating to.


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