logincontext.java

来自「java jdk 1.4的源码」· Java 代码 · 共 840 行 · 第 1/3 页

     * that <code>Requisite</code> and <code>Sufficient</code> semantics are
     * ignored for this method.  This guarantees that proper cleanup
     * and state restoration can take place.
     * 
     * <p>
     *
     * @exception LoginException if the logout fails.
     */
    public void logout() throws LoginException {
	if (subject == null) {
	    throw new LoginException(ResourcesMgr.getString
		("null subject - logout called before login"));
	}

	invokeModule(LOGOUT_METHOD);
    }

    /**
     * Return the authenticated Subject.
     *
     * <p>
     *
     * @return the authenticated Subject.  If authentication fails
     *		and a Subject was not provided to this LoginContext's
     *		constructor, this method returns <code>null</code>.
     *		Otherwise, this method returns the provided Subject.
     */
    public Subject getSubject() {
	if (!loginSucceeded && !subjectProvided)
	    return null;
	return subject;
    }

    private void throwException(LoginException originalError, LoginException le)
    throws LoginException {
	LoginException error = (originalError != null) ? originalError : le;
	throw error;
    }

    /**
     * Invokes the login, commit, and logout methods
     * from a LoginModule inside a doPrivileged block.
     */
    private void invokeModule(String methodName) throws LoginException {
	try {
	    final String finalName = methodName;
	    java.security.AccessController.doPrivileged
		(new java.security.PrivilegedExceptionAction() {
		public Object run() throws LoginException {
		    invoke(finalName);
		    return null;
		}
	    });
	} catch (java.security.PrivilegedActionException pae) {
	    throw (LoginException)pae.getException();
	}
    }

    private void invoke(String methodName) throws LoginException {

	LoginException firstError = null;
	LoginException firstRequiredError = null;
	boolean success = false;

	for (int i = 0; i < moduleStack.length; i++) {

	    try {

		int mIndex = 0;
		Method[] methods = null;

		if (moduleStack[i].module != null) {
		    methods = moduleStack[i].module.getClass().getMethods();
		} else {

		    // instantiate the LoginModule
		    Class c = Class.forName
				(moduleStack[i].entry.getLoginModuleName(),
				true,
				contextClassLoader);

		    Constructor constructor = c.getConstructor(PARAMS);
		    Object[] args = { };

		    // allow any object to be a LoginModule
		    // as long as it conforms to the interface
		    moduleStack[i].module = constructor.newInstance(args);

		    methods = moduleStack[i].module.getClass().getMethods();

		    // call the LoginModule's initialize method
		    for (mIndex = 0; mIndex < methods.length; mIndex++) {
			if (methods[mIndex].getName().equals(INIT_METHOD))
			    break;
		    }

		    Object[] initArgs = {subject,
					callbackHandler,
					state,
					moduleStack[i].entry.getOptions() };
		    // invoke the LoginModule initialize method
		    methods[mIndex].invoke(moduleStack[i].module, initArgs);
		}

		// find the requested method in the LoginModule
		for (mIndex = 0; mIndex < methods.length; mIndex++) {
		    if (methods[mIndex].getName().equals(methodName))
			break;
		}

		// set up the arguments to be passed to the LoginModule method
		Object[] args = { };

		// invoke the LoginModule method
		boolean status = ((Boolean)methods[mIndex].invoke
				(moduleStack[i].module, args)).booleanValue();

		if (status == true) {

		    // if SUFFICIENT, return if no prior REQUIRED errors
		    if (!methodName.equals(ABORT_METHOD) &&
		        !methodName.equals(LOGOUT_METHOD) &&
			moduleStack[i].entry.getControlFlag() ==
		    AppConfigurationEntry.LoginModuleControlFlag.SUFFICIENT &&
			firstRequiredError == null) {

			if (debug != null)
			    debug.println(methodName + " SUFFICIENT success");
			return;
		    }

		    if (debug != null)
			debug.println(methodName + " success");
		    success = true;
		} else {
		    if (debug != null)
			debug.println(methodName + " ignored");
		}

	    } catch (NoSuchMethodException nsme) {
		MessageFormat form = new MessageFormat(ResourcesMgr.getString
			("unable to instantiate LoginModule, module, because " +
			"it does not provide a no-argument constructor"));
		Object[] source = {moduleStack[i].entry.getLoginModuleName()};
		throw new LoginException(form.format(source));
	    } catch (InstantiationException ie) {
		throw new LoginException(ResourcesMgr.getString
			("unable to instantiate LoginModule: ") +
			ie.getMessage());
	    } catch (ClassNotFoundException cnfe) {
		throw new LoginException(ResourcesMgr.getString
			("unable to find LoginModule class: ") +
			cnfe.getMessage());
	    } catch (IllegalAccessException iae) {
		throw new LoginException(ResourcesMgr.getString
			("unable to access LoginModule: ") +
			iae.getMessage());
	    } catch (InvocationTargetException ite) {

		// failure cases
		LoginException le;
		if (ite.getTargetException() instanceof LoginException) {
		    le = (LoginException)ite.getCause();
		} else {
		    // capture an unexpected LoginModule exception
		    java.io.StringWriter sw = new java.io.StringWriter();
		    ite.getCause().printStackTrace
						(new java.io.PrintWriter(sw));
		    sw.flush();
		    le = new LoginException(sw.toString());
		}

		if (moduleStack[i].entry.getControlFlag() ==
		    AppConfigurationEntry.LoginModuleControlFlag.REQUISITE) {

		    if (debug != null)
			debug.println(methodName + " REQUISITE failure");

		    // if REQUISITE, then immediately throw an exception
		    if (methodName.equals(ABORT_METHOD) ||
		        methodName.equals(LOGOUT_METHOD)) {
			if (firstRequiredError == null)
			    firstRequiredError = le;
		    } else {
			throwException(firstRequiredError, le);
		    }

		} else if (moduleStack[i].entry.getControlFlag() ==
		    AppConfigurationEntry.LoginModuleControlFlag.REQUIRED) {

		    if (debug != null)
			debug.println(methodName + " REQUIRED failure");

		    // mark down that a REQUIRED module failed
		    if (firstRequiredError == null)
			firstRequiredError = le;

		} else {

		    if (debug != null)
			debug.println(methodName + " OPTIONAL failure");

		    // mark down that an OPTIONAL module failed
		    if (firstError == null)
			firstError = le;
		}
	    }
	}

	// we went thru all the LoginModules.
	if (firstRequiredError != null) {
	    // a REQUIRED module failed -- return the error
	    throwException(firstRequiredError, null);
	} else if (success == false && firstError != null) {
	    // no module succeeded -- return the first error
	    throwException(firstError, null);
	} else if (success == false) {
	    // no module succeeded -- all modules were IGNORED
	    throwException(new LoginException
		(ResourcesMgr.getString("Login Failure: all modules ignored")),
		null);
	} else {
	    // success
	    return;
	}
    }

    /**
     * Wrap the application-provided CallbackHandler in our own
     * and invoke it within a privileged block, constrained by
     * the caller's AccessControlContext.
     */
    private static class SecureCallbackHandler implements CallbackHandler {

	private final java.security.AccessControlContext acc;
	private final CallbackHandler ch;

	SecureCallbackHandler(java.security.AccessControlContext acc,
			CallbackHandler ch) {
	    this.acc = acc;
	    this.ch = ch;
	}

	public void handle(Callback[] callbacks) throws java.io.IOException,
						UnsupportedCallbackException {
	    try {
		final Callback[] finalCallbacks = callbacks;
		java.security.AccessController.doPrivileged
		    (new java.security.PrivilegedExceptionAction() {
		    public Object run() throws java.io.IOException,
					UnsupportedCallbackException {	
			ch.handle(finalCallbacks);
			return null;
		    }
		}, acc);
	    } catch (java.security.PrivilegedActionException pae) {
		if (pae.getException() instanceof java.io.IOException) {
		    throw (java.io.IOException)pae.getException();
		} else {
		    throw (UnsupportedCallbackException)pae.getException();
		}
	    }
	}
    }

    /**
     * LoginModule information -
     *		incapsulates Configuration info and actual module instances
     */
    private static class ModuleInfo {
	AppConfigurationEntry entry;
	Object module;

	ModuleInfo(AppConfigurationEntry newEntry, Object newModule) {
	    this.entry = newEntry;
	    this.module = newModule;
	}
    }
}