Linux compat / changing compat path

[Gary Jennejohn]

On Wed, 21 Mar 2018 09:39:09 +0100
Stefan Esser <se at freebsd.org> wrote:

> Am 21.03.18 um 09:09 schrieb Gary Jennejohn:
> > On Tue, 20 Mar 2018 21:21:52 +0100
> > Georg Bege <georg at bege.email> wrote:
> >   
> >> Hello users,
> >>
> >> Im not sure if this is actually the right mailing list for my question.
> >> I was looking for something non-amd64 related - but somehow I didnt find that the other topics would be a better match too.
> >>
> >> Im looking for a way to change the `default` linux compatibility userspace path /compat/linux to something else.
> >> Basically right now, I've different jails (also Linux ones) where I keep software which is not compatible with my main system.
> >>
> >> Also the pkg available linux-c* packages cant suit every thing I need, so I'd like to run programs I've installed (or compiled) from my jails.
> >> It works if I change the above mentioned path with a symlink... however this is very unflexible.
> >> What would be good is if I could change it per environment - is there a way? Any environment variable perhaps?
> >> (And no LD_LIBRARY_PATH isnt cutting it in any cases)
> >>  
> > 
> > emulation would be the correct mailing list.
> > 
> > This is defined in /usr/ports/Mk/bsd.port.mk as
> > 	LINUXBASE?=             /compat/linux
> > so theoretically it could be overridden in /etc/make.conf.
> > 
> > But you would have to recompile all your Linux ports.  
> 
> And you want to change occurances of /compat/linux in the kernel (and possibly
> some libraries and user programs), e.g. in /sys/amd64/linux/linux_sysvec.c ...
> 
> There is some magic that makes an exec of /bin/sh look up /compat/linux/bin/sh
> first, if performed from within a program running under Linux emulation, and
> if you need that behavior, you have to adjust at least the kernel sources.
> 
> Maybe the hard-coded "/compat/linux" should be replaced by a macro, to allow
> easy modification without loss of functionality ...
> 

Thanks, Stefan.  I completely forgot about the kernel stuff.  Makes
me wonder why LINUXBASE is even overrideable in the ports tree.

-- 
Gary Jennejohn