$NetBSD: patch-ab,v 1.4 2005/01/21 14:42:10 wiz Exp $

--- sanitize.c.orig	2005-01-21 15:34:42.000000000 +0100
+++ sanitize.c
@@ -0,0 +1,81 @@
+/*
+ * Path sanitation code by Ludwig Nussel <ludwig.nussel@suse.de>. Public Domain.
+ */
+
+#include "unarj.h"
+
+#include <string.h>
+#include <limits.h>
+#include <stdio.h>
+
+#ifndef PATH_CHAR
+#define PATH_CHAR '/'
+#endif
+#ifndef MIN
+#define MIN(x,y) ((x)<(y)?(x):(y))
+#endif
+
+/* copy src into dest converting the path to a relative one inside the current
+ * directory. dest must hold at least len bytes */
+void copy_path_relative(char *dest, char *src, size_t len)
+{
+    char* o = dest;
+    char* p = src;
+
+    *o = '\0';
+
+    while(*p && *p == PATH_CHAR) ++p;
+    for(; len && *p;)
+    {
+	src = p;
+	p = strchr(src, PATH_CHAR);
+	if(!p) p = src+strlen(src);
+
+	/* . => skip */
+	if(p-src == 1 && *src == '.' )
+	{
+	    if(*p) src = ++p;
+	}
+	/* .. => pop one */
+	else if(p-src == 2 && *src == '.' && src[1] == '.')
+	{
+	    if(o != dest)
+	    {
+		char* tmp;
+		*o = '\0';
+		tmp = strrchr(dest, PATH_CHAR);
+		if(!tmp)
+		{
+		    len += o-dest;
+		    o = dest;
+		    if(*p) ++p;
+		}
+		else
+		{
+		    len += o-tmp;
+		    o = tmp;
+		    if(*p) ++p;
+		}
+	    }
+	    else /* nothing to pop */
+		if(*p) ++p;
+	}
+	else
+	{
+	    size_t copy;
+	    if(o != dest)
+	    {
+		--len;
+		*o++ = PATH_CHAR;
+	    }
+	    copy = MIN(p-src,len);
+	    memcpy(o, src, copy);
+	    len -= copy;
+	    src += copy;
+	    o += copy;
+	    if(*p) ++p;
+	}
+	while(*p && *p == PATH_CHAR) ++p;
+    }
+    o[len?0:-1] = '\0';
+}