Re: Parameter expansion, patterns and fnmatch

[Herbert Xu <herbert@gondor.apana.org.au>]

On Sat, Sep 03, 2016 at 03:19:57PM +0200, Harald van Dijk wrote:
> 
> But yeah, sure, if the bug has been there for over 10 years, and I'm
> unable to find older versions of dash to check, I would have guessed
> that dash indeed has never worked this way.

OK it looks like this actually wasn't the original behaviour.
It was introduced along with the character class support.  So
with that in mind, I feel a lot happier in changing the behaviour
of the case statement.

I've changed your patch slightly and will commit it if there are
no other issues.

---8<---
Subject: expand - Fix dangling left square brackets in patterns

When there is an unmatched left square bracket in patterns, pmatch
will behave strangely and exhibit undefined behaviour.  This patch
(based on Harld van Dijk's original) fixes this by treating it as
a literal left square bracket.

Reported-by: Olof Johansson <olof@ethup.se>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/src/expand.c b/src/expand.c
index 36bea76..2a50830 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -1584,14 +1584,14 @@ pmatch(const char *pattern, const char *string)
 				p++;
 			}
 			found = 0;
-			chr = *q++;
+			chr = *q;
 			if (chr == '\0')
 				return 0;
 			c = *p++;
 			do {
 				if (!c) {
 					p = startp;
-					c = *p;
+					c = '[';
 					goto dft;
 				}
 				if (c == '[') {
@@ -1618,6 +1618,7 @@ pmatch(const char *pattern, const char *string)
 			} while ((c = *p++) != ']');
 			if (found == invert)
 				return 0;
+			q++;
 			break;
 		}
 dft:	        default:
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt