28 import java.security.AccessControlContext;
29 import java.security.AccessController;
30 import java.security.ProtectionDomain;
31 import java.security.PrivilegedAction;
32 import java.util.concurrent.atomic.AtomicInteger;
33
34 /**
35 * A thread that has no permissions, is not a member of any user-defined
36 * ThreadGroup and supports the ability to erase ThreadLocals.
37 */
38 public final class InnocuousThread extends Thread {
39 private static final jdk.internal.misc.Unsafe UNSAFE;
40 private static final long THREAD_LOCALS;
41 private static final long INHERITABLE_THREAD_LOCALS;
42 private static final ThreadGroup INNOCUOUSTHREADGROUP;
43 private static final AccessControlContext ACC;
44 private static final long INHERITEDACCESSCONTROLCONTEXT;
45 private static final long CONTEXTCLASSLOADER;
46
47 private static final AtomicInteger threadNumber = new AtomicInteger(1);
48
49 public InnocuousThread(Runnable target) {
50 this(INNOCUOUSTHREADGROUP, target,
51 "InnocuousThread-" + threadNumber.getAndIncrement());
52 }
53
54 public InnocuousThread(Runnable target, String name) {
55 this(INNOCUOUSTHREADGROUP, target, name);
56 }
57
58 public InnocuousThread(ThreadGroup group, Runnable target, String name) {
59 super(group, target, name, 0L, false);
60 UNSAFE.putOrderedObject(this, INHERITEDACCESSCONTROLCONTEXT, ACC);
61 UNSAFE.putOrderedObject(this, CONTEXTCLASSLOADER, ClassLoader.getSystemClassLoader());
62 }
63
64 @Override
65 public void setUncaughtExceptionHandler(UncaughtExceptionHandler x) {
66 // silently fail
67 }
68
69 @Override
70 public void setContextClassLoader(ClassLoader cl) {
71 // Allow clearing of the TCCL to remove the reference to the system classloader.
72 if (cl == null)
73 super.setContextClassLoader(null);
74 else
75 throw new SecurityException("setContextClassLoader");
76 }
77
78 /**
79 * Drops all thread locals (and inherited thread locals).
80 */
81 public final void eraseThreadLocals() {
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28 import java.security.AccessControlContext;
29 import java.security.AccessController;
30 import java.security.ProtectionDomain;
31 import java.security.PrivilegedAction;
32 import java.util.concurrent.atomic.AtomicInteger;
33
34 /**
35 * A thread that has no permissions, is not a member of any user-defined
36 * ThreadGroup and supports the ability to erase ThreadLocals.
37 */
38 public final class InnocuousThread extends Thread {
39 private static final jdk.internal.misc.Unsafe UNSAFE;
40 private static final long THREAD_LOCALS;
41 private static final long INHERITABLE_THREAD_LOCALS;
42 private static final ThreadGroup INNOCUOUSTHREADGROUP;
43 private static final AccessControlContext ACC;
44 private static final long INHERITEDACCESSCONTROLCONTEXT;
45 private static final long CONTEXTCLASSLOADER;
46
47 private static final AtomicInteger threadNumber = new AtomicInteger(1);
48 private static String newName() {
49 return "InnocuousThread-" + threadNumber.getAndIncrement();
50 }
51
52 /**
53 * Returns a new InnocuousThread with an auto-generated thread name
54 * and its context class loader is set to the system class loader.
55 */
56 public static Thread newThread(Runnable target) {
57 return newThread(newName(), target);
58 }
59
60 /**
61 * Returns a new InnocuousThread with its context class loader
62 * set to the system class loader.
63 */
64 public static Thread newThread(String name, Runnable target) {
65 return new InnocuousThread(INNOCUOUSTHREADGROUP,
66 target,
67 name,
68 ClassLoader.getSystemClassLoader());
69 }
70
71 /**
72 * Returns a new InnocuousThread with an auto-generated thread name.
73 * Its context class loader is set to null.
74 */
75 public static Thread newSystemThread(Runnable target) {
76 return newSystemThread(newName(), target);
77 }
78
79 /**
80 * Returns a new InnocuousThread with null context class loader.
81 */
82 public static Thread newSystemThread(String name, Runnable target) {
83 return new InnocuousThread(INNOCUOUSTHREADGROUP,
84 target, name, null);
85 }
86
87 private InnocuousThread(ThreadGroup group, Runnable target, String name, ClassLoader tccl) {
88 super(group, target, name, 0L, false);
89 UNSAFE.putOrderedObject(this, INHERITEDACCESSCONTROLCONTEXT, ACC);
90 UNSAFE.putOrderedObject(this, CONTEXTCLASSLOADER, tccl);
91 }
92
93 @Override
94 public void setUncaughtExceptionHandler(UncaughtExceptionHandler x) {
95 // silently fail
96 }
97
98 @Override
99 public void setContextClassLoader(ClassLoader cl) {
100 // Allow clearing of the TCCL to remove the reference to the system classloader.
101 if (cl == null)
102 super.setContextClassLoader(null);
103 else
104 throw new SecurityException("setContextClassLoader");
105 }
106
107 /**
108 * Drops all thread locals (and inherited thread locals).
109 */
110 public final void eraseThreadLocals() {
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