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036:
037: package edu.rice.cs.util;
038:
039: import java.security.*;
040:
041: /** Not used anymore. <p>
042: * A security manager to prevent exiting the slaveVM indiscriminately. This manager disallows System.exit
043: * (unless you call {@link #exitVM}). It also disallows setting a security manager, since this would override
044: * the exit prevention! If this security manager is enabled and an exit is attempted, either via System.exit
045: * or via {@link #exitVM} when exiting is blocked, a {@link ExitingNotAllowedException} will be thrown.
046: *
047: * @version $Id: PreventExitSecurityManager.java 4260 2007-10-10 20:28:34Z mgricken $
048: */
049: public class PreventExitSecurityManager extends SecurityManager {
050:
051: private static final Permission SET_MANAGER_PERM = new RuntimePermission(
052: "setSecurityManager");
053:
054: private final SecurityManager _parent;
055:
056: /** Has an unauthorized exit been attempted? */
057: private boolean _exitAttempted = false;
058:
059: /** Is it time to exit, for real? */
060: private boolean _timeToExit = false;
061:
062: /** Are we in exit blocking mode? */
063: private boolean _blockExit = false;
064:
065: /** Is it time to unset this security manager? */
066: private boolean _timeToDeactivate = false;
067:
068: /** Creates a PreventExitSecurityManager, delegating all permission checks except for exiting to the given parent
069: * manager.
070: * @param parent SecurityManager to delegate permission to. This may be null, signifying to allow all.
071: */
072: private PreventExitSecurityManager(final SecurityManager parent) {
073: _parent = parent;
074: edu.rice.cs.util.Log log = new edu.rice.cs.util.Log(
075: "secman.txt", true);
076: log.log("Creating new PreventExitSecurityManager");
077: }
078:
079: /** Creates a new exit-preventing security manager, using the previous security manager to delegate to.
080: */
081: public static PreventExitSecurityManager activate() {
082: SecurityManager currentMgr = System.getSecurityManager();
083: if (currentMgr instanceof PreventExitSecurityManager)
084: return (PreventExitSecurityManager) currentMgr;
085:
086: PreventExitSecurityManager mgr = new PreventExitSecurityManager(
087: System.getSecurityManager());
088: System.setSecurityManager(mgr);
089: return mgr;
090: }
091:
092: /** Removes this security manager. */
093: public void deactivate() {
094: _timeToDeactivate = true;
095: System.setSecurityManager(_parent);
096: }
097:
098: /** Exits the VM unless exiting is presently blocked. Blocking exit is used in test cases that want to see if we
099: * try to exit.
100: */
101: public void exitVM(int status) {
102: // Utilities.showDebug("exitVm(" + status + ") called");
103: if (!_blockExit)
104: _timeToExit = true;
105: System.exit(status);
106: }
107:
108: /** Sets whether exiting the VM is unconditionally blocked or not. It's useful to block exiting to allow test cases
109: * to pretend to exit, just to make sure it would have exited under certain conditions.
110: * @param b If true, exiting will never be allowed until set false.
111: */
112: public void setBlockExit(boolean b) {
113: _blockExit = b;
114: }
115:
116: /** Returns whether a System.exit was attempted since the last time this method was called. */
117: public boolean exitAttempted() {
118: boolean old = _exitAttempted;
119: _exitAttempted = false;
120: return old;
121: }
122:
123: /** Disallow setting security manager, but otherwise delegate to parent. */
124: public void checkPermission(Permission perm) {
125: if (perm.equals(SET_MANAGER_PERM)) {
126: if (!_timeToDeactivate)
127: throw new SecurityException(
128: "Can not reset security manager!");
129: } else {
130: if (_parent != null)
131: _parent.checkPermission(perm);
132: }
133: }
134:
135: public void checkExit(int status) {
136: if (!_timeToExit) {
137: _exitAttempted = true;
138: throw new ExitingNotAllowedException();
139: }
140: }
141: }
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