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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