Allow to specify umask(1) for a service started with rc(8)

[eugen_grosbein.net]

Summary

Currently we have multiple ways to modify environment (variables, working directory, limits etc.) for a service without touching its startup script but no way to change default umask(1) value. None of tools working with login classes change umask.

Also, we have no ways to extract umask by class name for shell script. Let us deal with the problem in simple way via new servicename_umask knob for rc.conf(5)

Some file-sharing services that create new files may benefit from it.

Test Plan

N/A

[eugen_grosbein.net]

Add missing chunk.

[pauamma_gundo.com]

Manual page change LGTM and seems consistent with what I think the intent of the rc.subr change is. Can't vouch for the implementation.

[eugen_grosbein.net]

In D36309#825545, @pauamma wrote:

Manual page change LGTM and seems consistent with what I think the intent of the rc.subr change is. Can't vouch for the implementation.

Thanks.

I'm going to commit this soon unless an objection raised.

[jlduran_gmail.com]

Is there a reason why this change was not MFCd? Thank you!

[eugen_grosbein.net]

In D36309#935684, @jlduran_gmail.com wrote:

Is there a reason why this change was not MFCd? Thank you!

Forgot about it. I've just merged it downto stable/12.

[jlduran_gmail.com]

In D36309#977969, @eugen_grosbein.net wrote:

In D36309#935684, @jlduran_gmail.com wrote:

Is there a reason why this change was not MFCd? Thank you!

Forgot about it. I've just merged it downto stable/12.

Thank you! /etc/rc.d/dmesg might just be its first consumer!