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7093090: Reduce synchronization in java.security.Policy.getPolicyNoCheck

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Reviewed-by: valeriep
This commit is contained in:
Sean Mullan 2011-11-22 08:58:31 -05:00
parent 665445dae9
commit 82c2945b95
1 changed files with 106 additions and 78 deletions
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184
jdk/src/share/classes/java/security/Policy.java
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@ -28,6 +28,7 @@ package java.security;
import java.util.Enumeration;
import java.util.WeakHashMap;
import java.util.concurrent.atomic.AtomicReference;
import sun.security.jca.GetInstance;
import sun.security.util.Debug;
import sun.security.util.SecurityConstants;
@ -60,8 +61,8 @@ import sun.security.util.SecurityConstants;
* with a standard type. The default policy type is "JavaPolicy".
*
* <p> Once a Policy instance has been installed (either by default, or by
* calling <code>setPolicy</code>),
* the Java runtime invokes its <code>implies</code> when it needs to
* calling <code>setPolicy</code>), the Java runtime invokes its
* <code>implies</code> method when it needs to
* determine whether executing code (encapsulated in a ProtectionDomain)
* can perform SecurityManager-protected operations. How a Policy object
* retrieves its policy data is up to the Policy implementation itself.
@ -94,18 +95,33 @@ public abstract class Policy {
public static final PermissionCollection UNSUPPORTED_EMPTY_COLLECTION =
new UnsupportedEmptyCollection();
/** the system-wide policy. */
private static Policy policy; // package private for AccessControlContext
// Information about the system-wide policy.
private static class PolicyInfo {
// the system-wide policy
final Policy policy;
// a flag indicating if the system-wide policy has been initialized
final boolean initialized;
PolicyInfo(Policy policy, boolean initialized) {
this.policy = policy;
this.initialized = initialized;
}
}
// PolicyInfo is stored in an AtomicReference
private static AtomicReference<PolicyInfo> policy =
new AtomicReference<>(new PolicyInfo(null, false));
private static final Debug debug = Debug.getInstance("policy");
// Cache mapping ProtectionDomain.Key to PermissionCollection
private WeakHashMap<ProtectionDomain.Key, PermissionCollection> pdMapping;
/** package private for AccessControlContext */
/** package private for AccessControlContext and ProtectionDomain */
static boolean isSet()
{
return policy != null;
PolicyInfo pi = policy.get();
return pi.policy != null && pi.initialized == true;
}
private static void checkPermission(String type) {
@ -143,80 +159,92 @@ public abstract class Policy {
/**
* Returns the installed Policy object, skipping the security check.
* Used by SecureClassLoader and getPolicy.
* Used by ProtectionDomain and getPolicy.
*
* @return the installed Policy.
*
*/
static synchronized Policy getPolicyNoCheck()
static Policy getPolicyNoCheck()
{
if (policy == null) {
String policy_class = null;
policy_class = AccessController.doPrivileged(
new PrivilegedAction<String>() {
public String run() {
return Security.getProperty("policy.provider");
}
});
if (policy_class == null) {
policy_class = "sun.security.provider.PolicyFile";
}
try {
policy = (Policy)
Class.forName(policy_class).newInstance();
} catch (Exception e) {
/*
* The policy_class seems to be an extension
* so we have to bootstrap loading it via a policy
* provider that is on the bootclasspath
* If it loads then shift gears to using the configured
* provider.
*/
// install the bootstrap provider to avoid recursion
policy = new sun.security.provider.PolicyFile();
final String pc = policy_class;
Policy p = AccessController.doPrivileged(
new PrivilegedAction<Policy>() {
public Policy run() {
try {
ClassLoader cl =
ClassLoader.getSystemClassLoader();
// we want the extension loader
ClassLoader extcl = null;
while (cl != null) {
extcl = cl;
cl = cl.getParent();
}
return (extcl != null ? (Policy)Class.forName(
pc, true, extcl).newInstance() : null);
} catch (Exception e) {
if (debug != null) {
debug.println("policy provider " +
pc +
" not available");
e.printStackTrace();
}
return null;
}
PolicyInfo pi = policy.get();
// Use double-check idiom to avoid locking if system-wide policy is
// already initialized
if (pi.initialized == false || pi.policy == null) {
synchronized (Policy.class) {
PolicyInfo pinfo = policy.get();
if (pinfo.policy == null) {
String policy_class = AccessController.doPrivileged(
new PrivilegedAction<String>() {
public String run() {
return Security.getProperty("policy.provider");
}
});
/*
* if it loaded install it as the policy provider. Otherwise
* continue to use the system default implementation
*/
if (p != null) {
policy = p;
} else {
if (debug != null) {
debug.println("using sun.security.provider.PolicyFile");
if (policy_class == null) {
policy_class = "sun.security.provider.PolicyFile";
}
try {
pinfo = new PolicyInfo(
(Policy) Class.forName(policy_class).newInstance(),
true);
} catch (Exception e) {
/*
* The policy_class seems to be an extension
* so we have to bootstrap loading it via a policy
* provider that is on the bootclasspath.
* If it loads then shift gears to using the configured
* provider.
*/
// install the bootstrap provider to avoid recursion
Policy polFile = new sun.security.provider.PolicyFile();
pinfo = new PolicyInfo(polFile, false);
policy.set(pinfo);
final String pc = policy_class;
Policy pol = AccessController.doPrivileged(
new PrivilegedAction<Policy>() {
public Policy run() {
try {
ClassLoader cl =
ClassLoader.getSystemClassLoader();
// we want the extension loader
ClassLoader extcl = null;
while (cl != null) {
extcl = cl;
cl = cl.getParent();
}
return (extcl != null ? (Policy)Class.forName(
pc, true, extcl).newInstance() : null);
} catch (Exception e) {
if (debug != null) {
debug.println("policy provider " +
pc +
" not available");
e.printStackTrace();
}
return null;
}
}
});
/*
* if it loaded install it as the policy provider. Otherwise
* continue to use the system default implementation
*/
if (pol != null) {
pinfo = new PolicyInfo(pol, true);
} else {
if (debug != null) {
debug.println("using sun.security.provider.PolicyFile");
}
pinfo = new PolicyInfo(polFile, true);
}
}
policy.set(pinfo);
}
return pinfo.policy;
}
}
return policy;
return pi.policy;
}
/**
@ -245,7 +273,7 @@ public abstract class Policy {
initPolicy(p);
}
synchronized (Policy.class) {
Policy.policy = p;
policy.set(new PolicyInfo(p, p != null));
}
}
@ -292,14 +320,14 @@ public abstract class Policy {
PermissionCollection policyPerms = null;
synchronized (p) {
if (p.pdMapping == null) {
p.pdMapping =
new WeakHashMap<ProtectionDomain.Key, PermissionCollection>();
p.pdMapping = new WeakHashMap<>();
}
}
if (policyDomain.getCodeSource() != null) {
if (Policy.isSet()) {
policyPerms = policy.getPermissions(policyDomain);
Policy pol = policy.get().policy;
if (pol != null) {
policyPerms = pol.getPermissions(policyDomain);
}
if (policyPerms == null) { // assume it has all
@ -434,7 +462,7 @@ public abstract class Policy {
type,
params);
} catch (NoSuchAlgorithmException nsae) {
return handleException (nsae);
return handleException(nsae);
}
}
@ -494,7 +522,7 @@ public abstract class Policy {
type,
params);
} catch (NoSuchAlgorithmException nsae) {
return handleException (nsae);
return handleException(nsae);
}
}
@ -808,7 +836,7 @@ public abstract class Policy {
*
* @param permission the Permission object to compare.
*
* @return true if "permission" is implied by the permissions in
* @return true if "permission" is implied by the permissions in
* the collection, false if not.
*/
@Override public boolean implies(Permission permission) {