/*
* Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* Copyright 2003 Wily Technology, Inc.
*/
#include <jni.h>
#include <jvmti.h>
#include "JPLISAssert.h"
#include "Reentrancy.h"
#include "JPLISAgent.h"
/*
* This module provides some utility functions to support the "same thread" re-entrancy management.
* Uses JVMTI TLS to store a single bit per thread.
* Non-zero means the thread is already inside; zero means the thread is not inside.
*/
/*
* Local prototypes
*/
/* Wrapper around set that does the set then re-fetches to make sure it worked.
* Degenerates to a simple set when assertions are disabled.
* This routine is only here because of a bug in the JVMTI where set to 0 fails.
*/
jvmtiError
confirmingTLSSet( jvmtiEnv * jvmtienv,
jthread thread,
const void * newValue);
/* Confirmation routine only; used to assure that the TLS slot holds the value we expect it to. */
void
assertTLSValue( jvmtiEnv * jvmtienv,
jthread thread,
const void * expected);
#define JPLIS_CURRENTLY_INSIDE_TOKEN ((void *) 0x7EFFC0BB)
#define JPLIS_CURRENTLY_OUTSIDE_TOKEN ((void *) 0)
jvmtiError
confirmingTLSSet( jvmtiEnv * jvmtienv,
jthread thread,
const void * newValue) {
jvmtiError error;
error = (*jvmtienv)->SetThreadLocalStorage(
jvmtienv,
thread,
newValue);
check_phase_ret_blob(error, error);
#if JPLISASSERT_ENABLEASSERTIONS
assertTLSValue( jvmtienv,
thread,
newValue);
#endif
return error;
}
void
assertTLSValue( jvmtiEnv * jvmtienv,
jthread thread,
const void * expected) {
jvmtiError error;
void * test = (void *) 0x99999999;
/* now check if we do a fetch we get what we wrote */
error = (*jvmtienv)->GetThreadLocalStorage(
jvmtienv,
thread,
&test);
check_phase_ret(error);
jplis_assert(error == JVMTI_ERROR_NONE);
jplis_assert(test == expected);
}
jboolean
tryToAcquireReentrancyToken( jvmtiEnv * jvmtienv,
jthread thread) {
jboolean result = JNI_FALSE;
jvmtiError error = JVMTI_ERROR_NONE;
void * storedValue = NULL;
error = (*jvmtienv)->GetThreadLocalStorage(
jvmtienv,
thread,
&storedValue);
check_phase_ret_false(error);
jplis_assert(error == JVMTI_ERROR_NONE);
if ( error == JVMTI_ERROR_NONE ) {
/* if this thread is already inside, just return false and short-circuit */
if ( storedValue == JPLIS_CURRENTLY_INSIDE_TOKEN ) {
result = JNI_FALSE;
}
else {
/* stuff in the sentinel and return true */
#if JPLISASSERT_ENABLEASSERTIONS
assertTLSValue( jvmtienv,
thread,
JPLIS_CURRENTLY_OUTSIDE_TOKEN);
#endif
error = confirmingTLSSet ( jvmtienv,
thread,
JPLIS_CURRENTLY_INSIDE_TOKEN);
jplis_assert(error == JVMTI_ERROR_NONE);
if ( error != JVMTI_ERROR_NONE ) {
result = JNI_FALSE;
}
else {
result = JNI_TRUE;
}
}
}
return result;
}
void
releaseReentrancyToken( jvmtiEnv * jvmtienv,
jthread thread) {
jvmtiError error = JVMTI_ERROR_NONE;
/* assert we hold the token */
#if JPLISASSERT_ENABLEASSERTIONS
assertTLSValue( jvmtienv,
thread,
JPLIS_CURRENTLY_INSIDE_TOKEN);
#endif
error = confirmingTLSSet( jvmtienv,
thread,
JPLIS_CURRENTLY_OUTSIDE_TOKEN);
jplis_assert(error == JVMTI_ERROR_NONE);
}