commit aac05c40926da9a9742e4eaaa1b02ea77539e223
from: David du Colombier <0intro@gmail.com>
via: Russ Cox <rsc@swtch.com>
date: Wed Nov 30 20:20:43 2011 UTC

vacfs: fix segfault when no prefix specified

R=rsc
CC=plan9port.codebot
http://codereview.appspot.com/5451052

commit - 83a5aba766bf2a2a84fe20df0d72d47a9105fdb2
commit + aac05c40926da9a9742e4eaaa1b02ea77539e223
blob - ac7d4a2a0383c73c295f28dc188f9cbee0418610
blob + 8f2fd84fb551248edc83ca77a32ca9b7e5b2675f
--- src/cmd/vac/file.c
+++ src/cmd/vac/file.c
@@ -1774,7 +1774,7 @@ vacfsopen(VtConn *z, char *file, int mode, ulong cache
 	char *prefix;
 	
 	if(vtparsescore(file, &prefix, score) >= 0){
-		if(strcmp(prefix, "vac") != 0){
+		if(prefix == nil || strcmp(prefix, "vac") != 0){
 			werrstr("not a vac file");
 			return nil;
 		}