7011804: SequenceInputStream with lots of empty substreams can cause StackOverflowError
Reviewed-by: chegar, alanb
--- a/jdk/src/share/classes/java/io/SequenceInputStream.java Thu Mar 13 07:24:12 2014 +0400
+++ b/jdk/src/share/classes/java/io/SequenceInputStream.java Thu Mar 13 07:52:17 2014 +0400
@@ -135,7 +135,7 @@
* @since JDK1.1
*/
public int available() throws IOException {
- if(in == null) {
+ if (in == null) {
return 0; // no way to signal EOF from available()
}
return in.available();
@@ -160,15 +160,14 @@
* @exception IOException if an I/O error occurs.
*/
public int read() throws IOException {
- if (in == null) {
- return -1;
+ while (in != null) {
+ int c = in.read();
+ if (c != -1) {
+ return c;
+ }
+ nextStream();
}
- int c = in.read();
- if (c == -1) {
- nextStream();
- return read();
- }
- return c;
+ return -1;
}
/**
@@ -204,13 +203,14 @@
} else if (len == 0) {
return 0;
}
-
- int n = in.read(b, off, len);
- if (n <= 0) {
+ do {
+ int n = in.read(b, off, len);
+ if (n > 0) {
+ return n;
+ }
nextStream();
- return read(b, off, len);
- }
- return n;
+ } while (in != null);
+ return -1;
}
/**
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/io/SequenceInputStream/LotsOfStreams.java Thu Mar 13 07:52:17 2014 +0400
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 7011804
+ * @summary SequenceInputStream#read() was implemented recursivly,
+ * which may cause stack overflow
+ */
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.io.SequenceInputStream;
+import java.util.Enumeration;
+
+public class LotsOfStreams {
+
+ static final int MAX_SUBSTREAMS = 32000;
+
+ public static void main(String[] argv) throws Exception {
+ try (InputStream stream =
+ new SequenceInputStream(new LOSEnumeration())) {
+ stream.read();
+ }
+ try (InputStream stream =
+ new SequenceInputStream(new LOSEnumeration())) {
+ byte[] b = new byte[1];
+ stream.read(b, 0, 1);
+ }
+ }
+
+ static class LOSEnumeration
+ implements Enumeration<InputStream> {
+
+ private static InputStream inputStream =
+ new ByteArrayInputStream(new byte[0]);
+ private int left = MAX_SUBSTREAMS;
+
+ public boolean hasMoreElements() {
+ return (left > 0);
+ }
+ public InputStream nextElement() {
+ left--;
+ return inputStream;
+ }
+ }
+}