Date: Mon, 1 Aug 2016 09:42:45 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Dimitry Andric <dim@FreeBSD.org> Cc: FreeBSD Current <freebsd-current@freebsd.org>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: BSD grep dumps core Message-ID: <20160801164245.GA31972@troutmask.apl.washington.edu> In-Reply-To: <54B0B5B7-25CF-4B7D-9874-73D33481CC1C@FreeBSD.org> References: <20160731153738.GA33643@troutmask.apl.washington.edu> <54B0B5B7-25CF-4B7D-9874-73D33481CC1C@FreeBSD.org>
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On Mon, Aug 01, 2016 at 06:22:16PM +0200, Dimitry Andric wrote:
> On 31 Jul 2016, at 17:37, Steve Kargl <sgk@troutmask.apl.washington.edu> wrote:
> > Script started on Sun Jul 31 08:30:56 2016
> > troutmask:sgk[200] cd gcc/gcc7
> > troutmask:sgk[201] svn status
> > ? 7.diff
> > ? decl.c.diff
> > ? gcc/fortran/old
> > ? gcc/fortran/pr38351.diff
> > ? gcc/fortran/pr41922.diff
> > ? gcc/fortran/pr69860.diff
> > ? trans-decl.c.diff
> > ? typescript
> > ? z1.diff
> > troutmask:sgk[202] svn status | grep -v -E ^\?
> > Segmentation fault (core dumped)
> > troutmask:sgk[203] svn status | grep -v -E ^"\?"
> > troutmask:sgk[204] exit
> > exit
> >
> > Script done on Sun Jul 31 08:31:54 2016
> >
> > The core dump happens with both tcsh and sh.
> >
> > The following works as expected
> >
> > troutmask:sgk[202] svn status | gnugrep -v -E ^\?
>
> Yes, '^?' is an invalid extended regular expression, but GNU grep does
> not complain about it, and simply discards the '?' character. Our BSD
> grep dies because it also attempts to discard, but then some later logic
> goes beyond the end of the buffer.
>
> Please try this fix:
>
> Index: usr.bin/grep/regex/tre-fastmatch.c
> ===================================================================
> --- usr.bin/grep/regex/tre-fastmatch.c (revision 303551)
> +++ usr.bin/grep/regex/tre-fastmatch.c (working copy)
> @@ -621,7 +621,7 @@ tre_compile_fast(fastmatch_t *fg, const tre_char_t
> case TRE_CHAR('+'):
> case TRE_CHAR('?'):
> if ((cflags & REG_EXTENDED) && (i == 0))
> - continue;
> + goto badpat;
> else if ((cflags & REG_EXTENDED) ^ !escaped)
> STORE_CHAR;
> else
>
> After this, bsdgrep errors out with:
>
> % bsdgrep -E '^?'
> bsdgrep: Invalid preceding regular expression
>
> which is much saner IMHO.
>
Dimitry,
Thanks for the quick patch. Yes, the patch works as advertised.
I agree that an error message is preferredi/saner than a segfault.
--
Steve
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