sysModel
Class MBSSecurityManager

java.lang.Object
  java.lang.SecurityManager
      sysModel.MBSSecurityManager

public class MBSSecurityManager
extends java.lang.SecurityManager

Special security manager that does not permit fish to call System.exit() or System.setSecurityManager().

Author:

Mathias Ricken

Field Summary

private MBSClassLoader	_classLoader Class loader.
private java.lang.String	_classPath Class path.
private java.lang.String[]	_classPathDirs Class path directories.
private boolean	_drJava True if DrJava is present.
private java.lang.ThreadGroup	_fishThreadGroup Fish thread group.
private boolean	_isProtected Flag if actions are protected.
private java.lang.String	_pathSep Path separator.
private java.util.Stack<java.lang.Boolean>	_protectionFlagStack Stack of protection flags.
private java.lang.SecurityManager	_sm SecurityManager to delegate to.

Fields inherited from class java.lang.SecurityManager

inCheck

Constructor Summary

MBSSecurityManager(boolean drJava)
Constructor.

Method Summary

void	checkAccess(java.lang.Thread t) Throws a SecurityException if the calling thread is not allowed to modify the thread argument.
void	checkAccess(java.lang.ThreadGroup g) Throws a SecurityException if the calling thread is not allowed to modify the thread group argument.
void	checkExit(int status) Throws a SecurityException if the calling thread is not allowed to cause the Java Virtual Machine to halt with the specified status code.
void	checkPermission(java.security.Permission perm) Throws a SecurityException if the requested access, specified by the given permission, is not permitted based on the security policy currently in effect.
java.lang.ClassLoader	getClassLoader() Return the class loader.
java.lang.ThreadGroup	getFishThreadGroup() Get the thread group the fish are run in.
protected boolean	isFishCaller() Returns true if a fish is somewhere on the call stack.
protected boolean	isOnClassPath(java.lang.String filename) Returns true if the filename is on the class path.
boolean	isProtected() Get the protection flag.
void	popProtected() Pops the top protection flag from the stack and sets it as new value.
void	pushProtected(boolean isProtected) Push the current protection flag onto the stack and set a new value.
void	setProtected(boolean isProtected) Set the protection flag.

Methods inherited from class java.lang.SecurityManager

checkAccept, checkAwtEventQueueAccess, checkConnect, checkConnect, checkCreateClassLoader, checkDelete, checkExec, checkLink, checkListen, checkMemberAccess, checkMulticast, checkMulticast, checkPackageAccess, checkPackageDefinition, checkPermission, checkPrintJobAccess, checkPropertiesAccess, checkPropertyAccess, checkRead, checkRead, checkRead, checkSecurityAccess, checkSetFactory, checkSystemClipboardAccess, checkTopLevelWindow, checkWrite, checkWrite, classDepth, classLoaderDepth, currentClassLoader, currentLoadedClass, getClassContext, getInCheck, getSecurityContext, getThreadGroup, inClass, inClassLoader

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_drJava

private boolean _drJava

True if DrJava is present.

_isProtected

private boolean _isProtected

Flag if actions are protected.

_sm

private java.lang.SecurityManager _sm

SecurityManager to delegate to.

_classPath

private java.lang.String _classPath

Class path.

_pathSep

private java.lang.String _pathSep

Path separator.

_classPathDirs

private java.lang.String[] _classPathDirs

Class path directories.

_fishThreadGroup

private java.lang.ThreadGroup _fishThreadGroup

Fish thread group.

_classLoader

private MBSClassLoader _classLoader

Class loader.

_protectionFlagStack

private java.util.Stack<java.lang.Boolean> _protectionFlagStack

Stack of protection flags.

Constructor Detail

MBSSecurityManager

public MBSSecurityManager(boolean drJava)

Constructor.

Parameters:

drJava - true if DrJava is running

Method Detail

setProtected

public void setProtected(boolean isProtected)

Set the protection flag.

Parameters:

isProtected - true if actions are to be protected

isProtected

public boolean isProtected()

Get the protection flag.

Returns:

true if actions are to be protected

pushProtected

public void pushProtected(boolean isProtected)

Push the current protection flag onto the stack and set a new value.

Parameters:

isProtected - true if actions are to be protected

popProtected

public void popProtected()

Pops the top protection flag from the stack and sets it as new value.

isOnClassPath

protected boolean isOnClassPath(java.lang.String filename)

Returns true if the filename is on the class path.

Parameters:

filename - filename to test

Returns:

true if on classpath

isFishCaller

protected boolean isFishCaller()

Returns true if a fish is somewhere on the call stack.

Returns:

true if fish is a caller

checkPermission

public void checkPermission(java.security.Permission perm)

Throws a SecurityException if the requested access, specified by the given permission, is not permitted based on the security policy currently in effect.

This method calls AccessController.checkPermission with the given permission.

Overrides:

checkPermission in class java.lang.SecurityManager

Parameters:

perm - the requested permission.

Throws:

java.lang.SecurityException - if access is not permitted based on the current security policy.

java.lang.NullPointerException - if the permission argument is null.

Since:

1.2

checkAccess

public void checkAccess(java.lang.Thread t)

Throws a SecurityException if the calling thread is not allowed to modify the thread argument.

This method is invoked for the current security manager by the stop, suspend, resume, setPriority, setName, and setDaemon methods of class Thread.

If the thread argument is a system thread (belongs to the thread group with a null parent) then this method calls checkPermission with the RuntimePermission("modifyThread") permission. If the thread argument is not a system thread, this method just returns silently.

Applications that want a stricter policy should override this method. If this method is overridden, the method that overrides it should additionally check to see if the calling thread has the RuntimePermission("modifyThread") permission, and if so, return silently. This is to ensure that code granted that permission (such as the SDK itself) is allowed to manipulate any thread.

If this method is overridden, then super.checkAccess should be called by the first statement in the overridden method, or the equivalent security check should be placed in the overridden method.

Overrides:

checkAccess in class java.lang.SecurityManager

Parameters:

t - the thread to be checked.

Throws:

java.lang.SecurityException - if the calling thread does not have permission to modify the thread.

java.lang.NullPointerException - if the thread argument is null.

See Also:

resume, setDaemon, setName, setPriority, stop, suspend, checkPermission

checkAccess

public void checkAccess(java.lang.ThreadGroup g)

Throws a SecurityException if the calling thread is not allowed to modify the thread group argument.

This method is invoked for the current security manager when a new child thread or child thread group is created, and by the setDaemon, setMaxPriority, stop, suspend, resume, and destroy methods of class ThreadGroup.

If the thread group argument is the system thread group ( has a null parent) then this method calls checkPermission with the RuntimePermission("modifyThreadGroup") permission. If the thread group argument is not the system thread group, this method just returns silently.

Applications that want a stricter policy should override this method. If this method is overridden, the method that overrides it should additionally check to see if the calling thread has the RuntimePermission("modifyThreadGroup") permission, and if so, return silently. This is to ensure that code granted that permission (such as the SDK itself) is allowed to manipulate any thread.

If this method is overridden, then super.checkAccess should be called by the first statement in the overridden method, or the equivalent security check should be placed in the overridden method.

Overrides:

checkAccess in class java.lang.SecurityManager

Parameters:

g - the thread group to be checked.

Throws:

java.lang.SecurityException - if the calling thread does not have permission to modify the thread group.

java.lang.NullPointerException - if the thread group argument is null.

See Also:

destroy, resume, setDaemon, setMaxPriority, stop, suspend, checkPermission

checkExit

public void checkExit(int status)

Throws a SecurityException if the calling thread is not allowed to cause the Java Virtual Machine to halt with the specified status code.

This method is invoked for the current security manager by the exit method of class Runtime. A status of 0 indicates success; other values indicate various errors.

This method calls checkPermission with the RuntimePermission("exitVM") permission.

If you override this method, then you should make a call to super.checkExit at the point the overridden method would normally throw an exception.

Overrides:

checkExit in class java.lang.SecurityManager

Parameters:

status - the exit status.

Throws:

java.lang.SecurityException - if the calling thread does not have permission to halt the Java Virtual Machine with the specified status.

See Also:

exit, checkPermission

getFishThreadGroup

public java.lang.ThreadGroup getFishThreadGroup()

Get the thread group the fish are run in.

Returns:

fish thread group

getClassLoader

public java.lang.ClassLoader getClassLoader()

Return the class loader.

Returns:

class loader