Re: question about hardcoded binary paths (swapon / mkswap)

[Mike Frysinger <vapier@gentoo.org>]

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On 01 Apr 2015 18:17, Ruediger Meier wrote:
> On Wednesday 01 April 2015, Isaac Dunham wrote:
> > On Wed, Apr 01, 2015 at 01:42:56PM +0200, Ruediger Meier wrote:
> > > I wonder about some hardcoded binary paths.
> > >
> > > Example swapon.c:
> > >
> > > #define PATH_MKSWAP    "/sbin/mkswap"
> > >
> > > There are a two problems.
> > > 1. It's wrong. We should use $sbindir from configure.
> > > 2. When called from our test-suite it will use a wrong (or
> > >    non-existend, broken) binary. This happens in test
> > > swapon/fixpgsz.
> > >
> > > The question is how to fix this.
> > >
> > > I would prefer to use "mkwsap" from the same directory like swapon
> > > or to simply execvp "mkswap" from PATH. But don't know if we want
> > > this. If we really want to keep a hardcoded sbindir then we would
> > > need "#ifdef TEST_PROGRAM".
> > >
> > > Any comments?
> >
> > The approach that seems obvious to me (assuming you want to keep the
> > hardcoded path) is:
> > -add -DSBINDIR="$sbindir" to CFLAGS
> 
> Yes, this would be easy. But my preferred logic would be like this
> 
> If "swapon" was called from PATH then just take mkswap from PATH too.
> If "/whatever/path/swapon" was called then look for mkswap in the same 
> path.
> 
> Maybe both cases also with or without fallback $sbindir, /sbin or $PATH.
> 
> I guess we should agree how somthing like this should be handeled in 
> general. "eject" is also using hardcoded "/bin/umount". 

seems like $PATH should always be used.  if you broke $PATH, well that's your 
fualt ... tools shouldn't generally be expected to work in the fact of hostile 
environments like this.
-mike

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