Experimental Physics and
Industrial Control System

"J. Lewis Muir" <[email protected]> · Wed, 5 Jul 2017 12:25:23 -0500

On 07/05, Andrew Johnson wrote:
> On 06/20/2017 03:38 PM, J. Lewis Muir wrote:
> > On top of that, I'm thinking the environment variable approach won't
> > even work on macOS Sierra (and El Capitan too?) with SIP enabled
> > since /bin/sh is a so-called protected process, and [1] says:
> > 
> >   Spawning children processes of processes restricted by System
> >   Integrity Protection, such as by launching a helper process in a
> >   bundle with NSTask or calling the exec(2) command, resets the Mach
> >   special ports of that child process. Any dynamic linker (dyld)
> >   environment variables, such as DYLD_LIBRARY_PATH, are purged when
> >   launching protected processes.
> >
> > So, even if DYLD_LIBRARY_PATH was set, it might get removed from the
> > executable's environment by SIP depending on how it gets executed.
> 
> That quotation is discussing launching processes inside a bundle. I
> don't think we would do that — I'm not a MacOS expert, but we don't
> create an EPICS Base bundle for the Mac, so that seems irrelevant to me.

I don't think so.  Just invoking /bin/sh from a shell exhibits the
purging of the DYLD_LIBRARY_PATH environment variable.  Consider the
following (on macOS Sierra):

===
% export DYLD_LIBRARY_PATH=a
% echo $DYLD_LIBRARY_PATH
a
% export MY_VAR=b
% echo $MY_VAR
b
% /bin/sh -c 'echo $DYLD_LIBRARY_PATH'

% /bin/sh -c 'echo $MY_VAR'
b
===

Lewis

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System