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Android: protect global jni cache. 

This fixes a issue that has been neglected for a while, namely, that
the access to the global jni caches where not sufficiently protected
for concurrent usage. This change also fixes an issue with the
thread-name storage.

Task-number: QTBUG-42755
Change-Id: I22f95ae7f44d1f6a13e289e52b050d98ccb9fb28
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
bb10
Christian Strømme 2014-11-21 11:33:09 +01:00 committed by Jani Heikkinen
parent d0ef89caab
commit f9408cc81c
1 changed files with 58 additions and 25 deletions
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83
src/corelib/kernel/qjni.cpp
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@ -37,6 +37,7 @@
#include <QtCore/qhash.h>
#include <QtCore/qstring.h>
#include <QtCore/QThread>
#include <QtCore/QReadWriteLock>
QT_BEGIN_NAMESPACE
@ -45,11 +46,6 @@ static inline QString keyBase()
return QStringLiteral("%1%2%3");
}
static inline QByteArray threadBaseName()
{
return QByteArrayLiteral("QtThread-");
}
static QString qt_convertJString(jstring string)
{
QJNIEnvironmentPrivate env;
@ -74,6 +70,7 @@ static inline bool exceptionCheckAndClear(JNIEnv *env)
typedef QHash<QString, jclass> JClassHash;
Q_GLOBAL_STATIC(JClassHash, cachedClasses)
Q_GLOBAL_STATIC(QReadWriteLock, cachedClassesLock)
static QString toDotEncodedClassName(const char *className)
{
@ -82,8 +79,9 @@ static QString toDotEncodedClassName(const char *className)
static jclass getCachedClass(const QString &classDotEnc, bool *isCached = 0)
{
QHash<QString, jclass>::iterator it = cachedClasses->find(classDotEnc);
const bool found = (it != cachedClasses->end());
QReadLocker locker(cachedClassesLock);
const QHash<QString, jclass>::const_iterator &it = cachedClasses->constFind(classDotEnc);
const bool found = (it != cachedClasses->constEnd());
if (isCached != 0)
*isCached = found;
@ -102,6 +100,12 @@ static jclass loadClassDotEnc(const QString &classDotEnc, JNIEnv *env)
if (!classLoader.isValid())
return 0;
QWriteLocker locker(cachedClassesLock);
// did we lose the race?
const QHash<QString, jclass>::const_iterator &it = cachedClasses->constFind(classDotEnc);
if (it != cachedClasses->constEnd())
return it.value();
QJNIObjectPrivate stringName = QJNIObjectPrivate::fromString(classDotEnc);
QJNIObjectPrivate classObject = classLoader.callObjectMethod("loadClass",
"(Ljava/lang/String;)Ljava/lang/Class;",
@ -121,6 +125,7 @@ inline static jclass loadClass(const char *className, JNIEnv *env)
typedef QHash<QString, jmethodID> JMethodIDHash;
Q_GLOBAL_STATIC(JMethodIDHash, cachedMethodID)
Q_GLOBAL_STATIC(QReadWriteLock, cachedMethodIDLock)
static jmethodID getCachedMethodID(JNIEnv *env,
jclass clazz,
@ -128,11 +133,24 @@ static jmethodID getCachedMethodID(JNIEnv *env,
const char *sig,
bool isStatic = false)
{
jmethodID id = 0;
// TODO: We need to use something else then the ref. from clazz to avoid collisions.
QString key = keyBase().arg(size_t(clazz)).arg(QLatin1String(name)).arg(QLatin1String(sig));
QHash<QString, jmethodID>::iterator it = cachedMethodID->find(key);
if (it == cachedMethodID->end()) {
const QString key = keyBase().arg(size_t(clazz)).arg(QLatin1String(name)).arg(QLatin1String(sig));
QHash<QString, jmethodID>::const_iterator it;
{
QReadLocker locker(cachedMethodIDLock);
it = cachedMethodID->constFind(key);
if (it != cachedMethodID->constEnd())
return it.value();
}
{
QWriteLocker locker(cachedMethodIDLock);
it = cachedMethodID->constFind(key);
if (it != cachedMethodID->constEnd())
return it.value();
jmethodID id = 0;
if (isStatic)
id = env->GetStaticMethodID(clazz, name, sig);
else
@ -142,14 +160,13 @@ static jmethodID getCachedMethodID(JNIEnv *env,
id = 0;
cachedMethodID->insert(key, id);
} else {
id = it.value();
return id;
}
return id;
}
typedef QHash<QString, jfieldID> JFieldIDHash;
Q_GLOBAL_STATIC(JFieldIDHash, cachedFieldID)
Q_GLOBAL_STATIC(QReadWriteLock, cachedFieldIDLock)
static jfieldID getCachedFieldID(JNIEnv *env,
jclass clazz,
@ -157,10 +174,23 @@ static jfieldID getCachedFieldID(JNIEnv *env,
const char *sig,
bool isStatic = false)
{
jfieldID id = 0;
QString key = keyBase().arg(size_t(clazz)).arg(QLatin1String(name)).arg(QLatin1String(sig));
QHash<QString, jfieldID>::iterator it = cachedFieldID->find(key);
if (it == cachedFieldID->end()) {
const QString key = keyBase().arg(size_t(clazz)).arg(QLatin1String(name)).arg(QLatin1String(sig));
QHash<QString, jfieldID>::const_iterator it;
{
QReadLocker locker(cachedFieldIDLock);
it = cachedFieldID->constFind(key);
if (it != cachedFieldID->constEnd())
return it.value();
}
{
QWriteLocker locker(cachedFieldIDLock);
it = cachedFieldID->constFind(key);
if (it != cachedFieldID->constEnd())
return it.value();
jfieldID id = 0;
if (isStatic)
id = env->GetStaticFieldID(clazz, name, sig);
else
@ -170,10 +200,8 @@ static jfieldID getCachedFieldID(JNIEnv *env,
id = 0;
cachedFieldID->insert(key, id);
} else {
id = it.value();
return id;
}
return id;
}
class QJNIEnvironmentPrivateTLS
@ -187,14 +215,14 @@ public:
Q_GLOBAL_STATIC(QThreadStorage<QJNIEnvironmentPrivateTLS *>, jniEnvTLS)
static const char qJniThreadName[] = "QtThread";
QJNIEnvironmentPrivate::QJNIEnvironmentPrivate()
: jniEnv(0)
{
JavaVM *vm = QtAndroidPrivate::javaVM();
if (vm->GetEnv((void**)&jniEnv, JNI_VERSION_1_6) == JNI_EDETACHED) {
const qulonglong id = reinterpret_cast<qulonglong>(QThread::currentThreadId());
const QByteArray threadName = threadBaseName() + QByteArray::number(id);
JavaVMAttachArgs args = { JNI_VERSION_1_6, threadName, Q_NULLPTR };
JavaVMAttachArgs args = { JNI_VERSION_1_6, qJniThreadName, Q_NULLPTR };
if (vm->AttachCurrentThread(&jniEnv, &args) != JNI_OK)
return;
}
@ -223,6 +251,12 @@ jclass QJNIEnvironmentPrivate::findClass(const char *className, JNIEnv *env)
return clazz;
if (env != 0) { // We got an env. pointer (We expect this to be the right env. and call FindClass())
QWriteLocker locker(cachedClassesLock);
const QHash<QString, jclass>::const_iterator &it = cachedClasses->constFind(classDotEnc);
// Did we lose the race?
if (it != cachedClasses->constEnd())
return it.value();
jclass fclazz = env->FindClass(className);
if (!exceptionCheckAndClear(env)) {
clazz = static_cast<jclass>(env->NewGlobalRef(fclazz));
@ -400,7 +434,6 @@ QJNIObjectPrivate::QJNIObjectPrivate(jobject obj)
d->m_jclass = static_cast<jclass>(env->NewGlobalRef(objectClass));
env->DeleteLocalRef(objectClass);
}
template <>
void QJNIObjectPrivate::callMethodV<void>(const char *methodName, const char *sig, va_list args) const
{