Gary Benson wrote:
> Robert Lougher wrote:
> > Do you have a testcase?
>
> If you build and run the attached testcase you ought to see only one
> checkPermission() between "Calling checkRead()" and "Done". ... In
> reality, JamVM chokes on it pretty hard. I _think_ what is
> happening is that the System.out.println in checkPermission() is
> itself doing some initialisation which causes security checks,
> causing an infinite loop.
The initialisation in question turns out to be:
1. Loading java.lang.StringBuffer to build the message.
2. Loading java.io.PrintStream to print it out.
3. Converting the message to bytes using String.getBytes(encoding).
Any one of them will trigger a security check and hence an infinite
loop. There's an awful lot I still don't undertstand here, but I'm
a step closer... Mañana.
In case anyone's interested I've attached a patched testcase and a
patch for classpath which together work on JamVM.
Cheers,
Gary
import java.security.Permission;
class Test
{
static class TestSecurityManager extends SecurityManager
{
public void checkPermission(Permission perm) {
System.out.println(" checkPermission(" + perm + ")");
}
}
public static void main(String[] args) {
java.lang.StringBuffer XXX1 = new java.lang.StringBuffer();
java.io.PrintStream XXX2 = new java.io.PrintStream(null);
try {
SecurityManager sm = new TestSecurityManager();
System.setSecurityManager(sm);
System.out.println("Calling checkRead()");
sm.checkRead("/");
System.out.println("Done");
}
catch (Throwable t) {
t.printStackTrace();
}
}
}
Index: java/lang/String.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/lang/String.java,v
retrieving revision 1.77
diff -u -r1.77 String.java
--- java/lang/String.java 6 Dec 2005 18:52:25 -0000 1.77
+++ java/lang/String.java 12 Dec 2005 17:40:55 -0000
@@ -680,35 +680,9 @@
*/
public byte[] getBytes(String enc) throws UnsupportedEncodingException
{
- try
- {
- CharsetEncoder cse = Charset.forName(enc).newEncoder();
- cse.onMalformedInput(CodingErrorAction.REPLACE);
- cse.onUnmappableCharacter(CodingErrorAction.REPLACE);
- ByteBuffer bbuf = cse.encode(CharBuffer.wrap(value, offset, count));
- if(bbuf.hasArray())
- return bbuf.array();
-
- // Doubt this will happen. But just in case.
- byte[] bytes = new byte[bbuf.remaining()];
- bbuf.get(bytes);
- return bytes;
- }
- catch(IllegalCharsetNameException e)
- {
- throw new UnsupportedEncodingException("Encoding: " + enc
- + " not found.");
- }
- catch(UnsupportedCharsetException e)
- {
- throw new UnsupportedEncodingException("Encoding: " + enc
- + " not found.");
- }
- catch(CharacterCodingException e)
- {
- // This shouldn't ever happen.
- throw (InternalError) new InternalError().initCause(e);
- }
+ byte[] bytes = new byte[length()];
+ getBytes(0, length(), bytes, 0);
+ return bytes;
}
/**
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