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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <android/binder_ibinder.h>
#include <android/binder_ibinder_platform.h>
#include <android/binder_libbinder.h>
#include "ibinder_internal.h"
#include <android/binder_stability.h>
#include <android/binder_status.h>
#include "parcel_internal.h"
#include "status_internal.h"
#include <android-base/logging.h>
#include <binder/IPCThreadState.h>
#include <binder/IResultReceiver.h>
#include <private/android_filesystem_config.h>
using DeathRecipient = ::android::IBinder::DeathRecipient;
using ::android::IBinder;
using ::android::IResultReceiver;
using ::android::Parcel;
using ::android::sp;
using ::android::status_t;
using ::android::String16;
using ::android::String8;
using ::android::wp;
namespace ABBinderTag {
static const void* kId = "ABBinder";
static void* kValue = static_cast<void*>(new bool{true});
void clean(const void* /*id*/, void* /*obj*/, void* /*cookie*/){/* do nothing */};
static void attach(const sp<IBinder>& binder) {
binder->attachObject(kId, kValue, nullptr /*cookie*/, clean);
}
static bool has(const sp<IBinder>& binder) {
return binder != nullptr && binder->findObject(kId) == kValue;
}
} // namespace ABBinderTag
namespace ABpBinderTag {
static std::mutex gLock;
static const void* kId = "ABpBinder";
struct Value {
wp<ABpBinder> binder;
};
void clean(const void* id, void* obj, void* cookie) {
CHECK(id == kId) << id << " " << obj << " " << cookie;
delete static_cast<Value*>(obj);
};
} // namespace ABpBinderTag
AIBinder::AIBinder(const AIBinder_Class* clazz) : mClazz(clazz) {}
AIBinder::~AIBinder() {}
std::optional<bool> AIBinder::associateClassInternal(const AIBinder_Class* clazz,
const String16& newDescriptor, bool set) {
std::lock_guard<std::mutex> lock(mClazzMutex);
if (mClazz == clazz) return true;
if (mClazz != nullptr) {
const String16& currentDescriptor = mClazz->getInterfaceDescriptor();
if (newDescriptor == currentDescriptor) {
LOG(ERROR) << __func__ << ": Class descriptors '" << currentDescriptor
<< "' match during associateClass, but they are different class objects. "
"Class descriptor collision?";
} else {
LOG(ERROR) << __func__
<< ": Class cannot be associated on object which already has a class. "
"Trying to associate to '"
<< newDescriptor << "' but already set to '" << currentDescriptor << "'.";
}
// always a failure because we know mClazz != clazz
return false;
}
if (set) {
// if this is a local object, it's not one known to libbinder_ndk
mClazz = clazz;
return true;
}
return {};
}
bool AIBinder::associateClass(const AIBinder_Class* clazz) {
if (clazz == nullptr) return false;
const String16& newDescriptor = clazz->getInterfaceDescriptor();
auto result = associateClassInternal(clazz, newDescriptor, false);
if (result.has_value()) return *result;
CHECK(asABpBinder() != nullptr); // ABBinder always has a descriptor
const String16& descriptor = getBinder()->getInterfaceDescriptor();
if (descriptor != newDescriptor) {
if (getBinder()->isBinderAlive()) {
LOG(ERROR) << __func__ << ": Expecting binder to have class '" << newDescriptor
<< "' but descriptor is actually '" << descriptor << "'.";
} else {
// b/155793159
LOG(ERROR) << __func__ << ": Cannot associate class '" << newDescriptor
<< "' to dead binder.";
}
return false;
}
return associateClassInternal(clazz, newDescriptor, true).value();
}
ABBinder::ABBinder(const AIBinder_Class* clazz, void* userData)
: AIBinder(clazz), BBinder(), mUserData(userData) {
CHECK(clazz != nullptr);
}
ABBinder::~ABBinder() {
getClass()->onDestroy(mUserData);
}
const String16& ABBinder::getInterfaceDescriptor() const {
return getClass()->getInterfaceDescriptor();
}
status_t ABBinder::dump(int fd, const ::android::Vector<String16>& args) {
AIBinder_onDump onDump = getClass()->onDump;
if (onDump == nullptr) {
return STATUS_OK;
}
// technically UINT32_MAX would be okay here, but INT32_MAX is expected since this may be
// null in Java
if (args.size() > INT32_MAX) {
LOG(ERROR) << "ABBinder::dump received too many arguments: " << args.size();
return STATUS_BAD_VALUE;
}
std::vector<String8> utf8Args; // owns memory of utf8s
utf8Args.reserve(args.size());
std::vector<const char*> utf8Pointers; // what can be passed over NDK API
utf8Pointers.reserve(args.size());
for (size_t i = 0; i < args.size(); i++) {
utf8Args.push_back(String8(args[i]));
utf8Pointers.push_back(utf8Args[i].c_str());
}
return onDump(this, fd, utf8Pointers.data(), utf8Pointers.size());
}
status_t ABBinder::onTransact(transaction_code_t code, const Parcel& data, Parcel* reply,
binder_flags_t flags) {
if (isUserCommand(code)) {
if (!data.checkInterface(this)) {
return STATUS_BAD_TYPE;
}
const AParcel in = AParcel::readOnly(this, &data);
AParcel out = AParcel(this, reply, false /*owns*/);
binder_status_t status = getClass()->onTransact(this, code, &in, &out);
return PruneStatusT(status);
} else if (code == SHELL_COMMAND_TRANSACTION && getClass()->handleShellCommand != nullptr) {
int in = data.readFileDescriptor();
int out = data.readFileDescriptor();
int err = data.readFileDescriptor();
int argc = data.readInt32();
std::vector<String8> utf8Args; // owns memory of utf8s
std::vector<const char*> utf8Pointers; // what can be passed over NDK API
for (int i = 0; i < argc && data.dataAvail() > 0; i++) {
utf8Args.push_back(String8(data.readString16()));
utf8Pointers.push_back(utf8Args[i].c_str());
}
data.readStrongBinder(); // skip over the IShellCallback
sp<IResultReceiver> resultReceiver = IResultReceiver::asInterface(data.readStrongBinder());
// Shell commands should only be callable by ADB.
uid_t uid = AIBinder_getCallingUid();
if (uid != AID_ROOT && uid != AID_SHELL) {
if (resultReceiver != nullptr) {
resultReceiver->send(-1);
}
return STATUS_PERMISSION_DENIED;
}
// Check that the file descriptors are valid.
if (in == STATUS_BAD_TYPE || out == STATUS_BAD_TYPE || err == STATUS_BAD_TYPE) {
if (resultReceiver != nullptr) {
resultReceiver->send(-1);
}
return STATUS_BAD_VALUE;
}
binder_status_t status = getClass()->handleShellCommand(
this, in, out, err, utf8Pointers.data(), utf8Pointers.size());
if (resultReceiver != nullptr) {
resultReceiver->send(status);
}
return status;
} else {
return BBinder::onTransact(code, data, reply, flags);
}
}
ABpBinder::ABpBinder(const ::android::sp<::android::IBinder>& binder)
: AIBinder(nullptr /*clazz*/), BpRefBase(binder) {
CHECK(binder != nullptr);
}
ABpBinder::~ABpBinder() {}
void ABpBinder::onLastStrongRef(const void* id) {
{
std::lock_guard<std::mutex> lock(ABpBinderTag::gLock);
// Since ABpBinder is OBJECT_LIFETIME_WEAK, we must remove this weak reference in order for
// the ABpBinder to be deleted. Since a strong reference to this ABpBinder object should no
// longer be able to exist at the time of this method call, there is no longer a need to
// recover it.
ABpBinderTag::Value* value =
static_cast<ABpBinderTag::Value*>(remote()->findObject(ABpBinderTag::kId));
if (value != nullptr) {
value->binder = nullptr;
}
}
BpRefBase::onLastStrongRef(id);
}
sp<AIBinder> ABpBinder::lookupOrCreateFromBinder(const ::android::sp<::android::IBinder>& binder) {
if (binder == nullptr) {
return nullptr;
}
if (ABBinderTag::has(binder)) {
return static_cast<ABBinder*>(binder.get());
}
// The following code ensures that for a given binder object (remote or local), if it is not an
// ABBinder then at most one ABpBinder object exists in a given process representing it.
std::lock_guard<std::mutex> lock(ABpBinderTag::gLock);
ABpBinderTag::Value* value =
static_cast<ABpBinderTag::Value*>(binder->findObject(ABpBinderTag::kId));
if (value == nullptr) {
value = new ABpBinderTag::Value;
binder->attachObject(ABpBinderTag::kId, static_cast<void*>(value), nullptr /*cookie*/,
ABpBinderTag::clean);
}
sp<ABpBinder> ret = value->binder.promote();
if (ret == nullptr) {
ret = new ABpBinder(binder);
value->binder = ret;
}
return ret;
}
struct AIBinder_Weak {
wp<AIBinder> binder;
};
AIBinder_Weak* AIBinder_Weak_new(AIBinder* binder) {
if (binder == nullptr) {
return nullptr;
}
return new AIBinder_Weak{wp<AIBinder>(binder)};
}
void AIBinder_Weak_delete(AIBinder_Weak* weakBinder) {
delete weakBinder;
}
AIBinder* AIBinder_Weak_promote(AIBinder_Weak* weakBinder) {
if (weakBinder == nullptr) {
return nullptr;
}
sp<AIBinder> binder = weakBinder->binder.promote();
AIBinder_incStrong(binder.get());
return binder.get();
}
AIBinder_Weak* AIBinder_Weak_clone(const AIBinder_Weak* weak) {
if (weak == nullptr) {
return nullptr;
}
return new AIBinder_Weak{weak->binder};
}
bool AIBinder_lt(const AIBinder* lhs, const AIBinder* rhs) {
if (lhs == nullptr || rhs == nullptr) return lhs < rhs;
return const_cast<AIBinder*>(lhs)->getBinder() < const_cast<AIBinder*>(rhs)->getBinder();
}
bool AIBinder_Weak_lt(const AIBinder_Weak* lhs, const AIBinder_Weak* rhs) {
if (lhs == nullptr || rhs == nullptr) return lhs < rhs;
return lhs->binder < rhs->binder;
}
AIBinder_Class::AIBinder_Class(const char* interfaceDescriptor, AIBinder_Class_onCreate onCreate,
AIBinder_Class_onDestroy onDestroy,
AIBinder_Class_onTransact onTransact)
: onCreate(onCreate),
onDestroy(onDestroy),
onTransact(onTransact),
mInterfaceDescriptor(interfaceDescriptor),
mWideInterfaceDescriptor(interfaceDescriptor) {}
AIBinder_Class* AIBinder_Class_define(const char* interfaceDescriptor,
AIBinder_Class_onCreate onCreate,
AIBinder_Class_onDestroy onDestroy,
AIBinder_Class_onTransact onTransact) {
if (interfaceDescriptor == nullptr || onCreate == nullptr || onDestroy == nullptr ||
onTransact == nullptr) {
return nullptr;
}
return new AIBinder_Class(interfaceDescriptor, onCreate, onDestroy, onTransact);
}
void AIBinder_Class_setOnDump(AIBinder_Class* clazz, AIBinder_onDump onDump) {
CHECK(clazz != nullptr) << "setOnDump requires non-null clazz";
// this is required to be called before instances are instantiated
clazz->onDump = onDump;
}
void AIBinder_Class_setHandleShellCommand(AIBinder_Class* clazz,
AIBinder_handleShellCommand handleShellCommand) {
CHECK(clazz != nullptr) << "setHandleShellCommand requires non-null clazz";
clazz->handleShellCommand = handleShellCommand;
}
const char* AIBinder_Class_getDescriptor(const AIBinder_Class* clazz) {
CHECK(clazz != nullptr) << "getDescriptor requires non-null clazz";
return clazz->getInterfaceDescriptorUtf8();
}
void AIBinder_DeathRecipient::TransferDeathRecipient::binderDied(const wp<IBinder>& who) {
CHECK(who == mWho) << who.unsafe_get() << "(" << who.get_refs() << ") vs " << mWho.unsafe_get()
<< " (" << mWho.get_refs() << ")";
mOnDied(mCookie);
sp<AIBinder_DeathRecipient> recipient = mParentRecipient.promote();
sp<IBinder> strongWho = who.promote();
// otherwise this will be cleaned up later with pruneDeadTransferEntriesLocked
if (recipient != nullptr && strongWho != nullptr) {
status_t result = recipient->unlinkToDeath(strongWho, mCookie);
if (result != ::android::DEAD_OBJECT) {
LOG(WARNING) << "Unlinking to dead binder resulted in: " << result;
}
}
mWho = nullptr;
}
AIBinder_DeathRecipient::AIBinder_DeathRecipient(AIBinder_DeathRecipient_onBinderDied onDied)
: mOnDied(onDied) {
CHECK(onDied != nullptr);
}
void AIBinder_DeathRecipient::pruneDeadTransferEntriesLocked() {
mDeathRecipients.erase(std::remove_if(mDeathRecipients.begin(), mDeathRecipients.end(),
[](const sp<TransferDeathRecipient>& tdr) {
return tdr->getWho() == nullptr;
}),
mDeathRecipients.end());
}
binder_status_t AIBinder_DeathRecipient::linkToDeath(const sp<IBinder>& binder, void* cookie) {
CHECK(binder != nullptr);
std::lock_guard<std::mutex> l(mDeathRecipientsMutex);
sp<TransferDeathRecipient> recipient =
new TransferDeathRecipient(binder, cookie, this, mOnDied);
status_t status = binder->linkToDeath(recipient, cookie, 0 /*flags*/);
if (status != STATUS_OK) {
return PruneStatusT(status);
}
mDeathRecipients.push_back(recipient);
pruneDeadTransferEntriesLocked();
return STATUS_OK;
}
binder_status_t AIBinder_DeathRecipient::unlinkToDeath(const sp<IBinder>& binder, void* cookie) {
CHECK(binder != nullptr);
std::lock_guard<std::mutex> l(mDeathRecipientsMutex);
for (auto it = mDeathRecipients.rbegin(); it != mDeathRecipients.rend(); ++it) {
sp<TransferDeathRecipient> recipient = *it;
if (recipient->getCookie() == cookie && recipient->getWho() == binder) {
mDeathRecipients.erase(it.base() - 1);
status_t status = binder->unlinkToDeath(recipient, cookie, 0 /*flags*/);
if (status != ::android::OK) {
LOG(ERROR) << __func__
<< ": removed reference to death recipient but unlink failed.";
}
return PruneStatusT(status);
}
}
return STATUS_NAME_NOT_FOUND;
}
// start of C-API methods
AIBinder* AIBinder_new(const AIBinder_Class* clazz, void* args) {
if (clazz == nullptr) {
LOG(ERROR) << __func__ << ": Must provide class to construct local binder.";
return nullptr;
}
void* userData = clazz->onCreate(args);
sp<AIBinder> ret = new ABBinder(clazz, userData);
ABBinderTag::attach(ret->getBinder());
AIBinder_incStrong(ret.get());
return ret.get();
}
bool AIBinder_isRemote(const AIBinder* binder) {
if (binder == nullptr) {
return false;
}
return binder->isRemote();
}
bool AIBinder_isAlive(const AIBinder* binder) {
if (binder == nullptr) {
return false;
}
return const_cast<AIBinder*>(binder)->getBinder()->isBinderAlive();
}
binder_status_t AIBinder_ping(AIBinder* binder) {
if (binder == nullptr) {
return STATUS_UNEXPECTED_NULL;
}
return PruneStatusT(binder->getBinder()->pingBinder());
}
binder_status_t AIBinder_dump(AIBinder* binder, int fd, const char** args, uint32_t numArgs) {
if (binder == nullptr) {
return STATUS_UNEXPECTED_NULL;
}
ABBinder* bBinder = binder->asABBinder();
if (bBinder != nullptr) {
AIBinder_onDump onDump = binder->getClass()->onDump;
if (onDump == nullptr) {
return STATUS_OK;
}
return PruneStatusT(onDump(bBinder, fd, args, numArgs));
}
::android::Vector<String16> utf16Args;
utf16Args.setCapacity(numArgs);
for (uint32_t i = 0; i < numArgs; i++) {
utf16Args.push(String16(String8(args[i])));
}
status_t status = binder->getBinder()->dump(fd, utf16Args);
return PruneStatusT(status);
}
binder_status_t AIBinder_linkToDeath(AIBinder* binder, AIBinder_DeathRecipient* recipient,
void* cookie) {
if (binder == nullptr || recipient == nullptr) {
LOG(ERROR) << __func__ << ": Must provide binder and recipient.";
return STATUS_UNEXPECTED_NULL;
}
// returns binder_status_t
return recipient->linkToDeath(binder->getBinder(), cookie);
}
binder_status_t AIBinder_unlinkToDeath(AIBinder* binder, AIBinder_DeathRecipient* recipient,
void* cookie) {
if (binder == nullptr || recipient == nullptr) {
LOG(ERROR) << __func__ << ": Must provide binder and recipient.";
return STATUS_UNEXPECTED_NULL;
}
// returns binder_status_t
return recipient->unlinkToDeath(binder->getBinder(), cookie);
}
uid_t AIBinder_getCallingUid() {
return ::android::IPCThreadState::self()->getCallingUid();
}
pid_t AIBinder_getCallingPid() {
return ::android::IPCThreadState::self()->getCallingPid();
}
void AIBinder_incStrong(AIBinder* binder) {
if (binder == nullptr) {
return;
}
binder->incStrong(nullptr);
}
void AIBinder_decStrong(AIBinder* binder) {
if (binder == nullptr) {
LOG(ERROR) << __func__ << ": on null binder";
return;
}
binder->decStrong(nullptr);
}
int32_t AIBinder_debugGetRefCount(AIBinder* binder) {
if (binder == nullptr) {
LOG(ERROR) << __func__ << ": on null binder";
return -1;
}
return binder->getStrongCount();
}
bool AIBinder_associateClass(AIBinder* binder, const AIBinder_Class* clazz) {
if (binder == nullptr) {
return false;
}
return binder->associateClass(clazz);
}
const AIBinder_Class* AIBinder_getClass(AIBinder* binder) {
if (binder == nullptr) {
return nullptr;
}
return binder->getClass();
}
void* AIBinder_getUserData(AIBinder* binder) {
if (binder == nullptr) {
return nullptr;
}
ABBinder* bBinder = binder->asABBinder();
if (bBinder == nullptr) {
return nullptr;
}
return bBinder->getUserData();
}
binder_status_t AIBinder_prepareTransaction(AIBinder* binder, AParcel** in) {
if (binder == nullptr || in == nullptr) {
LOG(ERROR) << __func__ << ": requires non-null parameters.";
return STATUS_UNEXPECTED_NULL;
}
const AIBinder_Class* clazz = binder->getClass();
if (clazz == nullptr) {
LOG(ERROR) << __func__
<< ": Class must be defined for a remote binder transaction. See "
"AIBinder_associateClass.";
return STATUS_INVALID_OPERATION;
}
*in = new AParcel(binder);
(*in)->get()->markForBinder(binder->getBinder());
status_t status = (*in)->get()->writeInterfaceToken(clazz->getInterfaceDescriptor());
binder_status_t ret = PruneStatusT(status);
if (ret != STATUS_OK) {
delete *in;
*in = nullptr;
}
return ret;
}
static void DestroyParcel(AParcel** parcel) {
delete *parcel;
*parcel = nullptr;
}
binder_status_t AIBinder_transact(AIBinder* binder, transaction_code_t code, AParcel** in,
AParcel** out, binder_flags_t flags) {
if (in == nullptr) {
LOG(ERROR) << __func__ << ": requires non-null in parameter";
return STATUS_UNEXPECTED_NULL;
}
using AutoParcelDestroyer = std::unique_ptr<AParcel*, void (*)(AParcel**)>;
// This object is the input to the transaction. This function takes ownership of it and deletes
// it.
AutoParcelDestroyer forIn(in, DestroyParcel);
if (!isUserCommand(code)) {
LOG(ERROR) << __func__ << ": Only user-defined transactions can be made from the NDK.";
return STATUS_UNKNOWN_TRANSACTION;
}
constexpr binder_flags_t kAllFlags = FLAG_PRIVATE_VENDOR | FLAG_ONEWAY | FLAG_CLEAR_BUF;
if ((flags & ~kAllFlags) != 0) {
LOG(ERROR) << __func__ << ": Unrecognized flags sent: " << flags;
return STATUS_BAD_VALUE;
}
if (binder == nullptr || *in == nullptr || out == nullptr) {
LOG(ERROR) << __func__ << ": requires non-null parameters.";
return STATUS_UNEXPECTED_NULL;
}
if ((*in)->getBinder() != binder) {
LOG(ERROR) << __func__ << ": parcel is associated with binder object " << binder
<< " but called with " << (*in)->getBinder();
return STATUS_BAD_VALUE;
}
*out = new AParcel(binder);
status_t status = binder->getBinder()->transact(code, *(*in)->get(), (*out)->get(), flags);
binder_status_t ret = PruneStatusT(status);
if (ret != STATUS_OK) {
delete *out;
*out = nullptr;
}
return ret;
}
AIBinder_DeathRecipient* AIBinder_DeathRecipient_new(
AIBinder_DeathRecipient_onBinderDied onBinderDied) {
if (onBinderDied == nullptr) {
LOG(ERROR) << __func__ << ": requires non-null onBinderDied parameter.";
return nullptr;
}
auto ret = new AIBinder_DeathRecipient(onBinderDied);
ret->incStrong(nullptr);
return ret;
}
void AIBinder_DeathRecipient_delete(AIBinder_DeathRecipient* recipient) {
if (recipient == nullptr) {
return;
}
recipient->decStrong(nullptr);
}
binder_status_t AIBinder_getExtension(AIBinder* binder, AIBinder** outExt) {
if (binder == nullptr || outExt == nullptr) {
if (outExt != nullptr) {
*outExt = nullptr;
}
return STATUS_UNEXPECTED_NULL;
}
sp<IBinder> ext;
status_t res = binder->getBinder()->getExtension(&ext);
if (res != android::OK) {
*outExt = nullptr;
return PruneStatusT(res);
}
sp<AIBinder> ret = ABpBinder::lookupOrCreateFromBinder(ext);
if (ret != nullptr) ret->incStrong(binder);
*outExt = ret.get();
return STATUS_OK;
}
binder_status_t AIBinder_setExtension(AIBinder* binder, AIBinder* ext) {
if (binder == nullptr || ext == nullptr) {
return STATUS_UNEXPECTED_NULL;
}
ABBinder* rawBinder = binder->asABBinder();
if (rawBinder == nullptr) {
return STATUS_INVALID_OPERATION;
}
rawBinder->setExtension(ext->getBinder());
return STATUS_OK;
}
// platform methods follow
void AIBinder_setRequestingSid(AIBinder* binder, bool requestingSid) {
ABBinder* localBinder = binder->asABBinder();
if (localBinder == nullptr) {
LOG(FATAL) << "AIBinder_setRequestingSid must be called on a local binder";
}
localBinder->setRequestingSid(requestingSid);
}
const char* AIBinder_getCallingSid() {
return ::android::IPCThreadState::self()->getCallingSid();
}
android::sp<android::IBinder> AIBinder_toPlatformBinder(AIBinder* binder) {
if (binder == nullptr) return nullptr;
return binder->getBinder();
}
AIBinder* AIBinder_fromPlatformBinder(const android::sp<android::IBinder>& binder) {
sp<AIBinder> ndkBinder = ABpBinder::lookupOrCreateFromBinder(binder);
AIBinder_incStrong(ndkBinder.get());
return ndkBinder.get();
}