HPCC-29679 Fix isPathInPlane issue when similar prefixes

The existing isPathInPlane() uses the startsWith() to check
whether a path is a plane path or not. It may return a wrong
result when 2 planes have similar path prefixes (ex. /abcd
and /abc).

Revise based on review: return false if prefix is empty/path is not

Signed-off-by: wangkx <[email protected]>

dali/base/dautils.cpp

@@ -119,7 +119,28 @@ IPropertyTree * getDropZonePlane(const char * name)
 
 bool isPathInPlane(IPropertyTree *plane, const char *path)
 {
-    return isEmptyString(path) || startsWith(path, plane->queryProp("@prefix"));
+    if (isEmptyString(path))
+        return true;
+
+    const char *prefix = plane->queryProp("@prefix");
+    if (isEmptyString(prefix))
+        return false; //prefix is empty, path is not - can't match.
+
+    while (*prefix && *prefix == *path)
+    {
+        path++;
+        prefix++;
+    }
+    if (0 == *prefix)
+    {
+        if (0 == *path || isPathSepChar(*path))
+            return true;
+        if (isPathSepChar(*(path - 1))) //implies both last characters of prefix and path were '/'
+            return true;
+    }
+    else if (0 == *path && isPathSepChar(*prefix) && (0 == *(prefix + 1)))
+        return true;
+    return false;
 }
 
 bool validateDropZone(IPropertyTree * plane, const char * path, const char * host, bool ipMatch)