From: nobu.nokada@...
Date: 2003-09-01T23:56:18+09:00
Subject: Re: Bug in mmap or ruby with ruby-1.8.0

Hi,

At Mon, 1 Sep 2003 23:20:37 +0900,
ts wrote:
>  s+d can be > e
> 
>  illegal access which give with a mapped file a segfault, with a normal
>  string it can work 

Indeed.


Index: re.c
===================================================================
RCS file: /cvs/ruby/src/ruby/re.c,v
retrieving revision 1.110
diff -u -2 -p -r1.110 re.c
--- re.c	16 Aug 2003 14:58:33 -0000	1.110
+++ re.c	1 Sep 2003 14:50:52 -0000
@@ -108,5 +108,6 @@ rb_memsearch(x0, m, y0, n)
 #define KR_REHASH(a, b, h) (((h) << 1) - ((a)<<d) + (b))
 
-    s = y; e = s + n - m + 1;
+    if (m > n) return -1;
+    s = y; e = s + n - m;
 
     /* Preprocessing */
@@ -117,4 +118,7 @@ rb_memsearch(x0, m, y0, n)
 
     if (ruby_ignorecase) {
+	if (n == m) {
+	    return rb_memcicmp(x, s, m) == 0 ? 0 : -1;
+	}
 	/* Prepare hash value */
 	for (hy = hx = i = 0; i < d; ++i) {
@@ -123,8 +127,6 @@ rb_memsearch(x0, m, y0, n)
 	}
 	/* Searching */
-	while (s < e) {
-	    if (hx == hy && rb_memcicmp(x, s, m) == 0) {
-		return s-y;
-	    }
+	while (hx != hy || rb_memcicmp(x, s, m)) {
+	    if (s >= e) return -1;
 	    hy = KR_REHASH(casetable[*s], casetable[*(s+d)], hy);
 	    s++;
@@ -132,4 +134,7 @@ rb_memsearch(x0, m, y0, n)
     }
     else {
+	if (n == m) {
+	    return memcmp(x, s, m) == 0 ? 0 : -1;
+	}
 	/* Prepare hash value */
 	for (hy = hx = i = 0; i < d; ++i) {
@@ -138,13 +143,11 @@ rb_memsearch(x0, m, y0, n)
 	}
 	/* Searching */
-	while (s < e) {
-	    if (hx == hy && memcmp(x, s, m) == 0) {
-		return s-y;
-	    }
+	while (hx != hy || memcmp(x, s, m)) {
+	    if (s >= e) return -1;
 	    hy = KR_REHASH(*s, *(s+d), hy);
 	    s++;
 	}
     }
-    return -1;
+    return s-y;
 }
 


-- 
Nobu Nakada