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Merge "Binder interface tokens: remove extra mallocs"

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This commit is contained in:
Steven Moreland
2020-10-05 18:55:58 +00:00
committed by Gerrit Code Review
parent a474d0e92f b219d80fb5
commit 57fd6a5f10
1 changed files with 60 additions and 33 deletions
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93
core/jni/android_os_Parcel.cpp
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@@ -638,50 +638,77 @@ static jboolean android_os_Parcel_hasFileDescriptors(jlong nativePtr)
return ret;
}
// String tries to allocate itself on the stack, within a known size, but will
// make a heap allocation if not.
template <size_t StackReserve>
class StackString {
public:
StackString(JNIEnv* env, jstring str) : mEnv(env), mJStr(str) {
LOG_ALWAYS_FATAL_IF(str == nullptr);
mSize = env->GetStringLength(str);
if (mSize > StackReserve) {
mStr = new jchar[mSize];
} else {
mStr = &mBuffer[0];
}
mEnv->GetStringRegion(str, 0, mSize, mStr);
}
~StackString() {
if (mStr != &mBuffer[0]) {
delete[] mStr;
}
}
const jchar* str() { return mStr; }
jsize size() { return mSize; }
private:
JNIEnv* mEnv;
jstring mJStr;
jchar mBuffer[StackReserve];
// pointer to &mBuffer[0] if string fits in mBuffer, otherwise owned
jchar* mStr;
jsize mSize;
};
// This size is chosen to be longer than most interface descriptors.
// Ones longer than this will be allocated on the heap.
typedef StackString<64> InterfaceDescriptorString;
static void android_os_Parcel_writeInterfaceToken(JNIEnv* env, jclass clazz, jlong nativePtr,
jstring name)
{
Parcel* parcel = reinterpret_cast<Parcel*>(nativePtr);
if (parcel != NULL) {
// In the current implementation, the token is just the serialized interface name that
// the caller expects to be invoking
const jchar* str = env->GetStringCritical(name, 0);
if (str != NULL) {
parcel->writeInterfaceToken(String16(
reinterpret_cast<const char16_t*>(str),
env->GetStringLength(name)));
env->ReleaseStringCritical(name, str);
}
if (parcel != nullptr) {
InterfaceDescriptorString descriptor(env, name);
parcel->writeInterfaceToken(reinterpret_cast<const char16_t*>(descriptor.str()),
descriptor.size());
}
}
static void android_os_Parcel_enforceInterface(JNIEnv* env, jclass clazz, jlong nativePtr, jstring name)
{
Parcel* parcel = reinterpret_cast<Parcel*>(nativePtr);
if (parcel != NULL) {
const jchar* str = env->GetStringCritical(name, 0);
if (str) {
IPCThreadState* threadState = IPCThreadState::self();
const int32_t oldPolicy = threadState->getStrictModePolicy();
const bool isValid = parcel->enforceInterface(
reinterpret_cast<const char16_t*>(str),
env->GetStringLength(name),
threadState);
env->ReleaseStringCritical(name, str);
if (isValid) {
const int32_t newPolicy = threadState->getStrictModePolicy();
if (oldPolicy != newPolicy) {
// Need to keep the Java-level thread-local strict
// mode policy in sync for the libcore
// enforcements, which involves an upcall back
// into Java. (We can't modify the
// Parcel.enforceInterface signature, as it's
// pseudo-public, and used via AIDL
// auto-generation...)
set_dalvik_blockguard_policy(env, newPolicy);
}
return; // everything was correct -> return silently
if (parcel != nullptr) {
InterfaceDescriptorString descriptor(env, name);
IPCThreadState* threadState = IPCThreadState::self();
const int32_t oldPolicy = threadState->getStrictModePolicy();
const bool isValid =
parcel->enforceInterface(reinterpret_cast<const char16_t*>(descriptor.str()),
descriptor.size(), threadState);
if (isValid) {
const int32_t newPolicy = threadState->getStrictModePolicy();
if (oldPolicy != newPolicy) {
// Need to keep the Java-level thread-local strict
// mode policy in sync for the libcore
// enforcements, which involves an upcall back
// into Java. (We can't modify the
// Parcel.enforceInterface signature, as it's
// pseudo-public, and used via AIDL
// auto-generation...)
set_dalvik_blockguard_policy(env, newPolicy);
}
return; // everything was correct -> return silently
}
}