Re: [PATCH] Do not abort compilation when dump file is /dev/*

[Richard Biener <rguenther@suse.de>]

On Fri, 19 Nov 2021, Bernhard Reutner-Fischer wrote:

> On Fri, 19 Nov 2021 10:35:26 +0100 (CET)
> Richard Biener via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> 
> > On Fri, 19 Nov 2021, Alexandre Oliva wrote:
> > 
> > > On Nov 18, 2021, Richard Biener <rguenther@suse.de> wrote:
> > >   
> > > > IMHO a more reasonable thing to do would be to not treat
> > > > -o /dev/null as a source for -dumpdir and friends.  Alex?  
> > > 
> > > +1
> > > 
> > > I think we already have some special-casing for /dev/null somewhere.  
> > 
> > Grepping finds me the following in system.h which is already checked
> > for in gcc.c in a few places indeed.
> > 
> > /* Provide a default for the HOST_BIT_BUCKET.
> >    This suffices for POSIX-like hosts.  */
> > 
> > #ifndef HOST_BIT_BUCKET
> > #define HOST_BIT_BUCKET "/dev/null"
> > #endif
> > 
> > 
> > > > You did the last re-org, where'd we put such special casing?  
> > > 
> > > I think we're missing something like this, to avoid messing with dumpdir
> > > with -o /dev/null.  We already use the same function when computing
> > > outbase just below this.  
> > 
> > Ah yeah, not_actual_file_p should do the trick indeed.  Giuliano, can
> > you update the patch like below?  I think we should still adjust
> > documentation as you did.
> 
> But that wouldn't cater for the general problem that the dumpdir is not
> writable, no? Why not just simply check access W_OK of the dumpdir?
> 
> Otherwise a dumpdir /dev/full or anyother such path will cause the same
> thing i guess.

I think those cases are OK to diagnose.  Just choosing a
not_actual_file_p output as base to derive the dump directory is
bad.

Richard.