On Mon, Jun 07, 2021 at 04:10:27AM +0300, Dmitry V. Levin wrote:
> On Mon, Jun 07, 2021 at 12:45:02AM +0300, Dmitry V. Levin wrote:
> > On Wed, May 26, 2021 at 12:08:19PM +0300, Egor Ignatov wrote:
> > > Fix behaviour introduced in 70b673e, where regexps with
> > > possessive quantifier("*+") didn't match.
> > > * lib/regexec.c
> > > (set_regs): Pop if CUR_NODE has already been checked only when
> > > we have a fail stack.
> > >
> > > Signed-off-by: Egor Ignatov <eg...@altlinux.org>
> > > ---
> > > Hi Paul,
> > >
> > > Do you have any test cases for bug 11053(glibc) for gnulib?
> > > This patch fixes the issue with "*+", but I'm not sure it
> > > doesn't break your fix for 11053.
> >
> > Thanks, the fix looks plausible, it doesn't break any tests
> > (including those introduced along with commit 70b673eb7),
>
> Apparently, there are more issues with commit 70b673eb7, for example:
>
> $ echo ab | sed -E 's/^(a*)*(.)\1/\1/'
> Segmentation fault
>
> $ echo ab | strace -enone -- sed --debug -E 's/^(a*)*(.)\1/\1/'
> SED PROGRAM:
> s/^(a*)*(.)\\1/\1/
> INPUT: 'STDIN' line 1
> PATTERN: ab
> COMMAND: s/^(a*)*(.)\\1/\1/
> MATCHED REGEX REGISTERS
> regex[0] = 0-2 'ab'
> regex[1] = 0--1 'ab!!ab
> '
> --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x20} ---
> +++ killed by SIGSEGV +++
> Segmentation fault
And here is a tests/test-regex.c entry for this bug:
diff --git a/tests/test-regex.c b/tests/test-regex.c
index 7ea73cfb6..fdb1a1f1d 100644
--- a/tests/test-regex.c
+++ b/tests/test-regex.c
@@ -120,6 +120,8 @@ static struct
{ "^a*+(.)", "ab", REG_EXTENDED, 2, { { 0, 2 }, { 1, 2 } } },
/* Test for ** match. */
{ "^(a*)*(.)", "ab", REG_EXTENDED, 3, { { 0, 2 }, { 0, 1 }, { 1, 2 } } },
+ /* Test for ** match with backreferences. */
+ { "^(a*)*\\1", "a", REG_EXTENDED, 2, { { 0, 0 }, { 0, 0 } } },
};
static void
--
ldv
