Appropriate path for mount/fsck sub-programs?

[John-Mark Gurney]

Rodney W. Grimes wrote this message on Thu, Sep 17, 2020 at 11:05 -0700:
> -- Start of PGP signed section.
> > Brooks Davis wrote this message on Wed, Sep 16, 2020 at 20:42 +0000:
> > > The mount and fsck commands have the ability to exec a mount_<fs> or
> > > fsck_<fs> program to do the actual work.  Currently they do this with:
> > > 
> > > execvP(execname, _PATH_SYSPATH, argv);
> > > 
> > > Where _PATH_SYSPATH is "/sbin:/usr/sbin" unless RESCUE is defined in
> > > which case it's "/rescue:/sbin:/usr/sbin".  This isn't very friendly to
> > > filesystems in ports and results in things like sysutils/e2fsprogs
> > > adding a link to /sbin.  I think the path should be expanded to include
> > > /usr/local/sbin at a minimum.  If it wasn't for the /rescue hack I'd be
> > > tempted to suggest just switching to `execvp` and using PATH.
> > > I see a few options (semi-sorted by level of change):
> > > 
> > > 0) Do nothing
> > > 1a) Add /usr/local/sbin to _PATH_SYSPATH (it's only used in mount and
> > >    fsck).
> 
> I would like to note that /usr/local is a choice made by a site
> and not an absolute global constant.  PREFIX can usually used
> to over ride this.
> 
> The assumption of /usr/local was once completly removed from
> FreeBSD and the ports system.  It has slowly crept back in
> and many places now contain hard coded, not easy to override
> constants.
> 
> This is yet another proposal to hard code this non-constant.

And where is this non-constant stored on the system such that it would
be possible to read and add this as needed?

> > > 1b) The same, but a new variable.
> > > 2) Switch to _PATH_DEFPATH (that also add .../bin directories).
> > > 3) Use PATH, optionally prepending /rescue
> > > 4) Use exevp and teach crunched_main.c to prepend /rescue to PATH.
> > > 
> > > I'd like opinions on what people think makes sense here.  I think (0)
> > > aligns poorly with current project directions, but how far to go is a
> > > question to answer before implementing something.
> > 
> > Since it's only used by fsck and mount, I'm firmly in the 1a camp..
> > 
> > This means that mount_* programs can be located in /usr/local/sbin as
> > well, which seems to complete this change...
> > 
> > 2 would make fsck_* programs "visible" when ports don't do the correct
> > thing, which 1b helps prevent.
> > 
> > 3 and 4 are dangerous to me, as it not everyone keeps . out of their
> > path, and might be tricked into running a bad binary..

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."