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package com.sun.media.sound;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.File;
import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.ServiceLoader;
import java.security.AccessController;
import java.security.PrivilegedAction;
import javax.sound.sampled.AudioPermission;
Managing security in the Java Sound implementation.
This class contains all code that uses and is used by
SecurityManager.doPrivileged().
Author: Matthias Pfisterer
/** Managing security in the Java Sound implementation.
* This class contains all code that uses and is used by
* SecurityManager.doPrivileged().
*
* @author Matthias Pfisterer
*/
final class JSSecurityManager {
Prevent instantiation.
/** Prevent instantiation.
*/
private JSSecurityManager() {
}
Checks if the VM currently has a SecurityManager installed.
Note that this may change over time. So the result of this method
should not be cached.
Returns: true if a SecurityManger is installed, false otherwise.
/** Checks if the VM currently has a SecurityManager installed.
* Note that this may change over time. So the result of this method
* should not be cached.
*
* @return true if a SecurityManger is installed, false otherwise.
*/
private static boolean hasSecurityManager() {
return (System.getSecurityManager() != null);
}
static void checkRecordPermission() throws SecurityException {
if(Printer.trace) Printer.trace("JSSecurityManager.checkRecordPermission()");
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new AudioPermission("record"));
}
}
Load properties from a file.
This method tries to load properties from the filename give into
the passed properties object.
If the file cannot be found or something else goes wrong,
the method silently fails.
Params: - properties – The properties bundle to store the values of the
properties file.
- filename – The filename of the properties file to load. This
filename is interpreted as relative to the subdirectory "lib" in
the JRE directory.
/** Load properties from a file.
This method tries to load properties from the filename give into
the passed properties object.
If the file cannot be found or something else goes wrong,
the method silently fails.
@param properties The properties bundle to store the values of the
properties file.
@param filename The filename of the properties file to load. This
filename is interpreted as relative to the subdirectory "lib" in
the JRE directory.
*/
static void loadProperties(final Properties properties,
final String filename) {
if(hasSecurityManager()) {
try {
// invoke the privileged action using 1.2 security
PrivilegedAction<Void> action = new PrivilegedAction<Void>() {
public Void run() {
loadPropertiesImpl(properties, filename);
return null;
}
};
AccessController.doPrivileged(action);
if(Printer.debug)Printer.debug("Loaded properties with JDK 1.2 security");
} catch (Exception e) {
if(Printer.debug)Printer.debug("Exception loading properties with JDK 1.2 security");
// try without using JDK 1.2 security
loadPropertiesImpl(properties, filename);
}
} else {
// not JDK 1.2 security, assume we already have permission
loadPropertiesImpl(properties, filename);
}
}
private static void loadPropertiesImpl(Properties properties,
String filename) {
if(Printer.trace)Printer.trace(">> JSSecurityManager: loadPropertiesImpl()");
String fname = System.getProperty("java.home");
try {
if (fname == null) {
throw new Error("Can't find java.home ??");
}
File f = new File(fname, "lib");
f = new File(f, filename);
fname = f.getCanonicalPath();
InputStream in = new FileInputStream(fname);
BufferedInputStream bin = new BufferedInputStream(in);
try {
properties.load(bin);
} finally {
if (in != null) {
in.close();
}
}
} catch (Throwable t) {
if (Printer.trace) {
System.err.println("Could not load properties file \"" + fname + "\"");
t.printStackTrace();
}
}
if(Printer.trace)Printer.trace("<< JSSecurityManager: loadPropertiesImpl() completed");
}
Create a Thread in the current ThreadGroup.
/** Create a Thread in the current ThreadGroup.
*/
static Thread createThread(final Runnable runnable,
final String threadName,
final boolean isDaemon, final int priority,
final boolean doStart) {
Thread thread = new Thread(runnable);
if (threadName != null) {
thread.setName(threadName);
}
thread.setDaemon(isDaemon);
if (priority >= 0) {
thread.setPriority(priority);
}
if (doStart) {
thread.start();
}
return thread;
}
static synchronized <T> List<T> getProviders(final Class<T> providerClass) {
List<T> p = new ArrayList<>(7);
// ServiceLoader creates "lazy" iterator instance, but it ensures that
// next/hasNext run with permissions that are restricted by whatever
// creates the ServiceLoader instance, so it requires to be called from
// privileged section
final PrivilegedAction<Iterator<T>> psAction =
new PrivilegedAction<Iterator<T>>() {
@Override
public Iterator<T> run() {
return ServiceLoader.load(providerClass).iterator();
}
};
final Iterator<T> ps = AccessController.doPrivileged(psAction);
// the iterator's hasNext() method looks through classpath for
// the provider class names, so it requires read permissions
PrivilegedAction<Boolean> hasNextAction = new PrivilegedAction<Boolean>() {
public Boolean run() {
return ps.hasNext();
}
};
while (AccessController.doPrivileged(hasNextAction)) {
try {
// the iterator's next() method creates instances of the
// providers and it should be called in the current security
// context
T provider = ps.next();
if (providerClass.isInstance(provider)) {
// $$mp 2003-08-22
// Always adding at the beginning reverses the
// order of the providers. So we no longer have
// to do this in AudioSystem and MidiSystem.
p.add(0, provider);
}
} catch (Throwable t) {
//$$fb 2002-11-07: do not fail on SPI not found
if (Printer.err) t.printStackTrace();
}
}
return p;
}
}