blob: 16023ffa8248b5de7a5464f9902d05f878426ad9 [file] [log] [blame] [edit]
/*
* Copyright (C) 2020 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.
*/
#define LOG_TAG "RpcSession"
#include <binder/RpcSession.h>
#include <dlfcn.h>
#include <inttypes.h>
#include <netinet/tcp.h>
#include <poll.h>
#include <unistd.h>
#include <string_view>
#include <binder/BpBinder.h>
#include <binder/Functional.h>
#include <binder/Parcel.h>
#include <binder/RpcServer.h>
#include <binder/RpcTransportRaw.h>
#include <binder/Stability.h>
#include <utils/String8.h>
#include "BuildFlags.h"
#include "FdTrigger.h"
#include "OS.h"
#include "RpcSocketAddress.h"
#include "RpcState.h"
#include "RpcTransportUtils.h"
#include "RpcWireFormat.h"
#include "Utils.h"
#if defined(__ANDROID__) && !defined(__ANDROID_RECOVERY__)
#include <jni.h>
extern "C" JavaVM* AndroidRuntimeGetJavaVM();
#endif
namespace android {
using namespace android::binder::impl;
using android::binder::borrowed_fd;
using android::binder::unique_fd;
RpcSession::RpcSession(std::unique_ptr<RpcTransportCtx> ctx) : mCtx(std::move(ctx)) {
LOG_RPC_DETAIL("RpcSession created %p", this);
mRpcBinderState = std::make_unique<RpcState>();
}
RpcSession::~RpcSession() {
LOG_RPC_DETAIL("RpcSession destroyed %p", this);
RpcMutexLockGuard _l(mMutex);
LOG_ALWAYS_FATAL_IF(mConnections.mIncoming.size() != 0,
"Should not be able to destroy a session with servers in use.");
}
sp<RpcSession> RpcSession::make() {
// Default is without TLS.
return make(binder::os::makeDefaultRpcTransportCtxFactory());
}
sp<RpcSession> RpcSession::make(std::unique_ptr<RpcTransportCtxFactory> rpcTransportCtxFactory) {
auto ctx = rpcTransportCtxFactory->newClientCtx();
if (ctx == nullptr) return nullptr;
return sp<RpcSession>::make(std::move(ctx));
}
void RpcSession::setMaxIncomingThreads(size_t threads) {
RpcMutexLockGuard _l(mMutex);
LOG_ALWAYS_FATAL_IF(mStartedSetup,
"Must set max incoming threads before setting up connections");
mMaxIncomingThreads = threads;
}
size_t RpcSession::getMaxIncomingThreads() {
RpcMutexLockGuard _l(mMutex);
return mMaxIncomingThreads;
}
void RpcSession::setMaxOutgoingConnections(size_t connections) {
RpcMutexLockGuard _l(mMutex);
LOG_ALWAYS_FATAL_IF(mStartedSetup,
"Must set max outgoing threads before setting up connections");
mMaxOutgoingConnections = connections;
}
size_t RpcSession::getMaxOutgoingThreads() {
RpcMutexLockGuard _l(mMutex);
return mMaxOutgoingConnections;
}
bool RpcSession::setProtocolVersionInternal(uint32_t version, bool checkStarted) {
if (!RpcState::validateProtocolVersion(version)) {
return false;
}
RpcMutexLockGuard _l(mMutex);
LOG_ALWAYS_FATAL_IF(checkStarted && mStartedSetup,
"Must set protocol version before setting up connections");
if (mProtocolVersion && version > *mProtocolVersion) {
ALOGE("Cannot upgrade explicitly capped protocol version %u to newer version %u",
*mProtocolVersion, version);
return false;
}
mProtocolVersion = version;
return true;
}
bool RpcSession::setProtocolVersion(uint32_t version) {
return setProtocolVersionInternal(version, true);
}
std::optional<uint32_t> RpcSession::getProtocolVersion() {
RpcMutexLockGuard _l(mMutex);
return mProtocolVersion;
}
void RpcSession::setFileDescriptorTransportMode(FileDescriptorTransportMode mode) {
RpcMutexLockGuard _l(mMutex);
LOG_ALWAYS_FATAL_IF(mStartedSetup,
"Must set file descriptor transport mode before setting up connections");
mFileDescriptorTransportMode = mode;
}
RpcSession::FileDescriptorTransportMode RpcSession::getFileDescriptorTransportMode() {
return mFileDescriptorTransportMode;
}
status_t RpcSession::setupUnixDomainClient(const char* path) {
return setupSocketClient(UnixSocketAddress(path));
}
status_t RpcSession::setupUnixDomainSocketBootstrapClient(unique_fd bootstrapFd) {
mBootstrapTransport =
mCtx->newTransport(RpcTransportFd(std::move(bootstrapFd)), mShutdownTrigger.get());
return setupClient([&](const std::vector<uint8_t>& sessionId, bool incoming) {
int socks[2];
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, socks) < 0) {
int savedErrno = errno;
ALOGE("Failed socketpair: %s", strerror(savedErrno));
return -savedErrno;
}
unique_fd clientFd(socks[0]), serverFd(socks[1]);
int zero = 0;
iovec iov{&zero, sizeof(zero)};
std::vector<std::variant<unique_fd, borrowed_fd>> fds;
fds.push_back(std::move(serverFd));
status_t status = mBootstrapTransport->interruptableWriteFully(mShutdownTrigger.get(), &iov,
1, std::nullopt, &fds);
if (status != OK) {
ALOGE("Failed to send fd over bootstrap transport: %s", statusToString(status).c_str());
return status;
}
return initAndAddConnection(RpcTransportFd(std::move(clientFd)), sessionId, incoming);
});
}
status_t RpcSession::setupVsockClient(unsigned int cid, unsigned int port) {
return setupSocketClient(VsockSocketAddress(cid, port));
}
status_t RpcSession::setupInetClient(const char* addr, unsigned int port) {
auto aiStart = InetSocketAddress::getAddrInfo(addr, port);
if (aiStart == nullptr) return UNKNOWN_ERROR;
for (auto ai = aiStart.get(); ai != nullptr; ai = ai->ai_next) {
InetSocketAddress socketAddress(ai->ai_addr, ai->ai_addrlen, addr, port);
if (status_t status = setupSocketClient(socketAddress); status == OK) return OK;
}
ALOGE("None of the socket address resolved for %s:%u can be added as inet client.", addr, port);
return NAME_NOT_FOUND;
}
status_t RpcSession::setupPreconnectedClient(unique_fd fd, std::function<unique_fd()>&& request) {
return setupClient([&](const std::vector<uint8_t>& sessionId, bool incoming) -> status_t {
if (!fd.ok()) {
fd = request();
if (!fd.ok()) return BAD_VALUE;
}
if (status_t res = binder::os::setNonBlocking(fd); res != OK) return res;
RpcTransportFd transportFd(std::move(fd));
status_t status = initAndAddConnection(std::move(transportFd), sessionId, incoming);
fd = unique_fd(); // Explicitly reset after move to avoid analyzer warning.
return status;
});
}
status_t RpcSession::addNullDebuggingClient() {
// Note: only works on raw sockets.
if (auto status = initShutdownTrigger(); status != OK) return status;
unique_fd serverFd(TEMP_FAILURE_RETRY(open("/dev/null", O_WRONLY | O_CLOEXEC)));
if (!serverFd.ok()) {
int savedErrno = errno;
ALOGE("Could not connect to /dev/null: %s", strerror(savedErrno));
return -savedErrno;
}
RpcTransportFd transportFd(std::move(serverFd));
auto server = mCtx->newTransport(std::move(transportFd), mShutdownTrigger.get());
if (server == nullptr) {
ALOGE("Unable to set up RpcTransport");
return UNKNOWN_ERROR;
}
return addOutgoingConnection(std::move(server), false);
}
sp<IBinder> RpcSession::getRootObject() {
ExclusiveConnection connection;
status_t status = ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
ConnectionUse::CLIENT, &connection);
if (status != OK) return nullptr;
return state()->getRootObject(connection.get(), sp<RpcSession>::fromExisting(this));
}
status_t RpcSession::getRemoteMaxThreads(size_t* maxThreads) {
ExclusiveConnection connection;
status_t status = ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
ConnectionUse::CLIENT, &connection);
if (status != OK) return status;
return state()->getMaxThreads(connection.get(), sp<RpcSession>::fromExisting(this), maxThreads);
}
bool RpcSession::shutdownAndWait(bool wait) {
RpcMutexUniqueLock _l(mMutex);
LOG_ALWAYS_FATAL_IF(mShutdownTrigger == nullptr, "Shutdown trigger not installed");
mShutdownTrigger->trigger();
if (wait) {
LOG_ALWAYS_FATAL_IF(mShutdownListener == nullptr, "Shutdown listener not installed");
mShutdownListener->waitForShutdown(_l, sp<RpcSession>::fromExisting(this));
LOG_ALWAYS_FATAL_IF(!mConnections.mThreads.empty(), "Shutdown failed");
}
_l.unlock();
if (status_t res = state()->sendObituaries(sp<RpcSession>::fromExisting(this)); res != OK) {
ALOGE("Failed to send obituaries as the RpcSession is shutting down: %s",
statusToString(res).c_str());
}
mRpcBinderState->clear();
return true;
}
status_t RpcSession::transact(const sp<IBinder>& binder, uint32_t code, const Parcel& data,
Parcel* reply, uint32_t flags) {
ExclusiveConnection connection;
status_t status =
ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
(flags & IBinder::FLAG_ONEWAY) ? ConnectionUse::CLIENT_ASYNC
: ConnectionUse::CLIENT,
&connection);
if (status != OK) return status;
return state()->transact(connection.get(), binder, code, data,
sp<RpcSession>::fromExisting(this), reply, flags);
}
status_t RpcSession::sendDecStrong(const BpBinder* binder) {
// target is 0 because this is used to free BpBinder objects
return sendDecStrongToTarget(binder->getPrivateAccessor().rpcAddress(), 0 /*target*/);
}
status_t RpcSession::sendDecStrongToTarget(uint64_t address, size_t target) {
ExclusiveConnection connection;
status_t status = ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
ConnectionUse::CLIENT_REFCOUNT, &connection);
if (status != OK) return status;
return state()->sendDecStrongToTarget(connection.get(), sp<RpcSession>::fromExisting(this),
address, target);
}
status_t RpcSession::readId() {
{
RpcMutexLockGuard _l(mMutex);
LOG_ALWAYS_FATAL_IF(mForServer != nullptr, "Can only update ID for client.");
}
ExclusiveConnection connection;
status_t status = ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
ConnectionUse::CLIENT, &connection);
if (status != OK) return status;
status = state()->getSessionId(connection.get(), sp<RpcSession>::fromExisting(this), &mId);
if (status != OK) return status;
LOG_RPC_DETAIL("RpcSession %p has id %s", this, HexString(mId.data(), mId.size()).c_str());
return OK;
}
void RpcSession::WaitForShutdownListener::onSessionAllIncomingThreadsEnded(
const sp<RpcSession>& session) {
(void)session;
}
void RpcSession::WaitForShutdownListener::onSessionIncomingThreadEnded() {
mShutdownCount += 1;
mCv.notify_all();
}
void RpcSession::WaitForShutdownListener::waitForShutdown(RpcMutexUniqueLock& lock,
const sp<RpcSession>& session) {
while (mShutdownCount < session->mConnections.mMaxIncoming) {
if (std::cv_status::timeout == mCv.wait_for(lock, std::chrono::seconds(1))) {
ALOGE("Waiting for RpcSession to shut down (1s w/o progress): %zu incoming connections "
"still %zu/%zu fully shutdown.",
session->mConnections.mIncoming.size(), mShutdownCount.load(),
session->mConnections.mMaxIncoming);
}
}
}
void RpcSession::preJoinThreadOwnership(RpcMaybeThread thread) {
LOG_ALWAYS_FATAL_IF(thread.get_id() != rpc_this_thread::get_id(), "Must own this thread");
{
RpcMutexLockGuard _l(mMutex);
mConnections.mThreads[thread.get_id()] = std::move(thread);
}
}
RpcSession::PreJoinSetupResult RpcSession::preJoinSetup(
std::unique_ptr<RpcTransport> rpcTransport) {
// must be registered to allow arbitrary client code executing commands to
// be able to do nested calls (we can't only read from it)
sp<RpcConnection> connection = assignIncomingConnectionToThisThread(std::move(rpcTransport));
status_t status;
if (connection == nullptr) {
status = DEAD_OBJECT;
} else {
status =
mRpcBinderState->readConnectionInit(connection, sp<RpcSession>::fromExisting(this));
}
return PreJoinSetupResult{
.connection = std::move(connection),
.status = status,
};
}
namespace {
#if !defined(__ANDROID__) || defined(__ANDROID_RECOVERY__)
class JavaThreadAttacher {};
#else
// RAII object for attaching / detaching current thread to JVM if Android Runtime exists. If
// Android Runtime doesn't exist, no-op.
class JavaThreadAttacher {
public:
JavaThreadAttacher() {
// Use dlsym to find androidJavaAttachThread because libandroid_runtime is loaded after
// libbinder.
auto vm = getJavaVM();
if (vm == nullptr) return;
char threadName[16];
if (0 != pthread_getname_np(pthread_self(), threadName, sizeof(threadName))) {
constexpr const char* defaultThreadName = "UnknownRpcSessionThread";
memcpy(threadName, defaultThreadName,
std::min<size_t>(sizeof(threadName), strlen(defaultThreadName) + 1));
}
LOG_RPC_DETAIL("Attaching current thread %s to JVM", threadName);
JavaVMAttachArgs args;
args.version = JNI_VERSION_1_2;
args.name = threadName;
args.group = nullptr;
JNIEnv* env;
LOG_ALWAYS_FATAL_IF(vm->AttachCurrentThread(&env, &args) != JNI_OK,
"Cannot attach thread %s to JVM", threadName);
mAttached = true;
}
~JavaThreadAttacher() {
if (!mAttached) return;
auto vm = getJavaVM();
LOG_ALWAYS_FATAL_IF(vm == nullptr,
"Unable to detach thread. No JavaVM, but it was present before!");
LOG_RPC_DETAIL("Detaching current thread from JVM");
int ret = vm->DetachCurrentThread();
if (ret == JNI_OK) {
mAttached = false;
} else {
ALOGW("Unable to detach current thread from JVM (%d)", ret);
}
}
private:
JavaThreadAttacher(const JavaThreadAttacher&) = delete;
void operator=(const JavaThreadAttacher&) = delete;
bool mAttached = false;
static JavaVM* getJavaVM() {
static auto fn = reinterpret_cast<decltype(&AndroidRuntimeGetJavaVM)>(
dlsym(RTLD_DEFAULT, "AndroidRuntimeGetJavaVM"));
if (fn == nullptr) return nullptr;
return fn();
}
};
#endif
} // namespace
void RpcSession::join(sp<RpcSession>&& session, PreJoinSetupResult&& setupResult) {
sp<RpcConnection>& connection = setupResult.connection;
if (setupResult.status == OK) {
LOG_ALWAYS_FATAL_IF(!connection, "must have connection if setup succeeded");
[[maybe_unused]] JavaThreadAttacher javaThreadAttacher;
while (true) {
status_t status = session->state()->getAndExecuteCommand(connection, session,
RpcState::CommandType::ANY);
if (status != OK) {
LOG_RPC_DETAIL("Binder connection thread closing w/ status %s",
statusToString(status).c_str());
break;
}
}
} else {
ALOGE("Connection failed to init, closing with status %s",
statusToString(setupResult.status).c_str());
}
sp<RpcSession::EventListener> listener;
{
RpcMutexLockGuard _l(session->mMutex);
auto it = session->mConnections.mThreads.find(rpc_this_thread::get_id());
LOG_ALWAYS_FATAL_IF(it == session->mConnections.mThreads.end());
it->second.detach();
session->mConnections.mThreads.erase(it);
listener = session->mEventListener.promote();
}
// done after all cleanup, since session shutdown progresses via callbacks here
if (connection != nullptr) {
LOG_ALWAYS_FATAL_IF(!session->removeIncomingConnection(connection),
"bad state: connection object guaranteed to be in list");
}
session = nullptr;
if (listener != nullptr) {
listener->onSessionIncomingThreadEnded();
}
}
sp<RpcServer> RpcSession::server() {
RpcServer* unsafeServer = mForServer.unsafe_get();
sp<RpcServer> server = mForServer.promote();
LOG_ALWAYS_FATAL_IF((unsafeServer == nullptr) != (server == nullptr),
"wp<> is to avoid strong cycle only");
return server;
}
status_t RpcSession::setupClient(const std::function<status_t(const std::vector<uint8_t>& sessionId,
bool incoming)>& connectAndInit) {
{
RpcMutexLockGuard _l(mMutex);
LOG_ALWAYS_FATAL_IF(mStartedSetup, "Must only setup session once");
mStartedSetup = true;
if constexpr (!kEnableRpcThreads) {
LOG_ALWAYS_FATAL_IF(mMaxIncomingThreads > 0,
"Incoming threads are not supported on single-threaded libbinder");
// mMaxIncomingThreads should not change from here to its use below,
// since we set mStartedSetup==true and setMaxIncomingThreads checks
// for that
}
}
if (auto status = initShutdownTrigger(); status != OK) return status;
auto oldProtocolVersion = mProtocolVersion;
auto cleanup = make_scope_guard([&] {
// if any threads are started, shut them down
(void)shutdownAndWait(true);
mShutdownListener = nullptr;
mEventListener.clear();
mId.clear();
mShutdownTrigger = nullptr;
mRpcBinderState = std::make_unique<RpcState>();
// protocol version may have been downgraded - if we reuse this object
// to connect to another server, force that server to request a
// downgrade again
mProtocolVersion = oldProtocolVersion;
mConnections = {};
// clear mStartedSetup so that we can reuse this RpcSession
mStartedSetup = false;
});
if (status_t status = connectAndInit({}, false /*incoming*/); status != OK) return status;
{
ExclusiveConnection connection;
if (status_t status = ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
ConnectionUse::CLIENT, &connection);
status != OK)
return status;
uint32_t version;
if (status_t status =
state()->readNewSessionResponse(connection.get(),
sp<RpcSession>::fromExisting(this), &version);
status != OK)
return status;
if (!setProtocolVersionInternal(version, false)) return BAD_VALUE;
}
// TODO(b/189955605): we should add additional sessions dynamically
// instead of all at once.
size_t numThreadsAvailable;
if (status_t status = getRemoteMaxThreads(&numThreadsAvailable); status != OK) {
ALOGE("Could not get max threads after initial session setup: %s",
statusToString(status).c_str());
return status;
}
if (status_t status = readId(); status != OK) {
ALOGE("Could not get session id after initial session setup: %s",
statusToString(status).c_str());
return status;
}
size_t outgoingConnections = std::min(numThreadsAvailable, mMaxOutgoingConnections);
ALOGI_IF(outgoingConnections != numThreadsAvailable,
"Server hints client to start %zu outgoing threads, but client will only start %zu "
"because it is preconfigured to start at most %zu outgoing threads.",
numThreadsAvailable, outgoingConnections, mMaxOutgoingConnections);
// TODO(b/189955605): we should add additional sessions dynamically
// instead of all at once - the other side should be responsible for setting
// up additional connections. We need to create at least one (unless 0 are
// requested to be set) in order to allow the other side to reliably make
// any requests at all.
// we've already setup one client
LOG_RPC_DETAIL("RpcSession::setupClient() instantiating %zu outgoing connections (server max: "
"%zu) and %zu incoming threads",
outgoingConnections, numThreadsAvailable, mMaxIncomingThreads);
for (size_t i = 0; i + 1 < outgoingConnections; i++) {
if (status_t status = connectAndInit(mId, false /*incoming*/); status != OK) return status;
}
for (size_t i = 0; i < mMaxIncomingThreads; i++) {
if (status_t status = connectAndInit(mId, true /*incoming*/); status != OK) return status;
}
cleanup.release();
return OK;
}
status_t RpcSession::setupSocketClient(const RpcSocketAddress& addr) {
return setupClient([&](const std::vector<uint8_t>& sessionId, bool incoming) {
return setupOneSocketConnection(addr, sessionId, incoming);
});
}
status_t RpcSession::setupOneSocketConnection(const RpcSocketAddress& addr,
const std::vector<uint8_t>& sessionId,
bool incoming) {
RpcTransportFd transportFd;
status_t status = singleSocketConnection(addr, mShutdownTrigger, &transportFd);
if (status != OK) return status;
return initAndAddConnection(std::move(transportFd), sessionId, incoming);
}
status_t singleSocketConnection(const RpcSocketAddress& addr,
const std::unique_ptr<FdTrigger>& shutdownTrigger,
RpcTransportFd* outFd) {
LOG_ALWAYS_FATAL_IF(outFd == nullptr,
"There is no reason to call this function without an outFd");
LOG_ALWAYS_FATAL_IF(shutdownTrigger == nullptr,
"FdTrigger argument is required so we don't get stuck in the connect call "
"if the server process shuts down.");
for (size_t tries = 0; tries < 5; tries++) {
if (tries > 0) usleep(10000);
unique_fd serverFd(TEMP_FAILURE_RETRY(
socket(addr.addr()->sa_family, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0)));
if (!serverFd.ok()) {
int savedErrno = errno;
ALOGE("Could not create socket at %s: %s", addr.toString().c_str(),
strerror(savedErrno));
return -savedErrno;
}
if (addr.addr()->sa_family == AF_INET || addr.addr()->sa_family == AF_INET6) {
int noDelay = 1;
int result =
setsockopt(serverFd.get(), IPPROTO_TCP, TCP_NODELAY, &noDelay, sizeof(noDelay));
if (result < 0) {
int savedErrno = errno;
ALOGE("Could not set TCP_NODELAY on %s: %s", addr.toString().c_str(),
strerror(savedErrno));
return -savedErrno;
}
}
RpcTransportFd transportFd(std::move(serverFd));
if (0 != TEMP_FAILURE_RETRY(connect(transportFd.fd.get(), addr.addr(), addr.addrSize()))) {
int connErrno = errno;
if (connErrno == EAGAIN || connErrno == EINPROGRESS) {
// For non-blocking sockets, connect() may return EAGAIN (for unix domain socket) or
// EINPROGRESS (for others). Call poll() and getsockopt() to get the error.
status_t pollStatus = shutdownTrigger->triggerablePoll(transportFd, POLLOUT);
if (pollStatus != OK) {
ALOGE("Could not POLLOUT after connect() on non-blocking socket: %s",
statusToString(pollStatus).c_str());
return pollStatus;
}
// Set connErrno to the errno that connect() would have set if the fd were blocking.
socklen_t connErrnoLen = sizeof(connErrno);
int ret = getsockopt(transportFd.fd.get(), SOL_SOCKET, SO_ERROR, &connErrno,
&connErrnoLen);
if (ret == -1) {
int savedErrno = errno;
ALOGE("Could not getsockopt() after connect() on non-blocking socket: %s. "
"(Original error from connect() is: %s)",
strerror(savedErrno), strerror(connErrno));
return -savedErrno;
}
// Retrieved the real connErrno as if connect() was called with a blocking socket
// fd. Continue checking connErrno.
}
if (connErrno == ECONNRESET) {
ALOGW("Connection reset on %s", addr.toString().c_str());
continue;
}
// connErrno could be zero if getsockopt determines so. Hence zero-check again.
if (connErrno != 0) {
ALOGE("Could not connect socket at %s: %s", addr.toString().c_str(),
strerror(connErrno));
return -connErrno;
}
}
LOG_RPC_DETAIL("Socket at %s client with fd %d", addr.toString().c_str(),
transportFd.fd.get());
*outFd = std::move(transportFd);
return OK;
}
ALOGE("Ran out of retries to connect to %s", addr.toString().c_str());
return UNKNOWN_ERROR;
}
status_t RpcSession::initAndAddConnection(RpcTransportFd fd, const std::vector<uint8_t>& sessionId,
bool incoming) {
LOG_ALWAYS_FATAL_IF(mShutdownTrigger == nullptr);
auto server = mCtx->newTransport(std::move(fd), mShutdownTrigger.get());
if (server == nullptr) {
ALOGE("%s: Unable to set up RpcTransport", __PRETTY_FUNCTION__);
return UNKNOWN_ERROR;
}
LOG_RPC_DETAIL("Socket at client with RpcTransport %p", server.get());
if (sessionId.size() > std::numeric_limits<uint16_t>::max()) {
ALOGE("Session ID too big %zu", sessionId.size());
return BAD_VALUE;
}
RpcConnectionHeader header{
.version = mProtocolVersion.value_or(RPC_WIRE_PROTOCOL_VERSION),
.options = 0,
.fileDescriptorTransportMode = static_cast<uint8_t>(mFileDescriptorTransportMode),
.sessionIdSize = static_cast<uint16_t>(sessionId.size()),
};
if (incoming) {
header.options |= RPC_CONNECTION_OPTION_INCOMING;
}
iovec headerIov{&header, sizeof(header)};
auto sendHeaderStatus = server->interruptableWriteFully(mShutdownTrigger.get(), &headerIov, 1,
std::nullopt, nullptr);
if (sendHeaderStatus != OK) {
ALOGE("Could not write connection header to socket: %s",
statusToString(sendHeaderStatus).c_str());
return sendHeaderStatus;
}
if (sessionId.size() > 0) {
iovec sessionIov{const_cast<void*>(static_cast<const void*>(sessionId.data())),
sessionId.size()};
auto sendSessionIdStatus =
server->interruptableWriteFully(mShutdownTrigger.get(), &sessionIov, 1,
std::nullopt, nullptr);
if (sendSessionIdStatus != OK) {
ALOGE("Could not write session ID ('%s') to socket: %s",
HexString(sessionId.data(), sessionId.size()).c_str(),
statusToString(sendSessionIdStatus).c_str());
return sendSessionIdStatus;
}
}
LOG_RPC_DETAIL("Socket at client: header sent");
if (incoming) {
return addIncomingConnection(std::move(server));
} else {
return addOutgoingConnection(std::move(server), true /*init*/);
}
}
status_t RpcSession::addIncomingConnection(std::unique_ptr<RpcTransport> rpcTransport) {
RpcMutex mutex;
RpcConditionVariable joinCv;
RpcMutexUniqueLock lock(mutex);
RpcMaybeThread thread;
sp<RpcSession> thiz = sp<RpcSession>::fromExisting(this);
bool ownershipTransferred = false;
thread = RpcMaybeThread([&]() {
RpcMutexUniqueLock threadLock(mutex);
std::unique_ptr<RpcTransport> movedRpcTransport = std::move(rpcTransport);
// NOLINTNEXTLINE(performance-unnecessary-copy-initialization)
sp<RpcSession> session = thiz;
session->preJoinThreadOwnership(std::move(thread));
// only continue once we have a response or the connection fails
auto setupResult = session->preJoinSetup(std::move(movedRpcTransport));
ownershipTransferred = true;
threadLock.unlock();
joinCv.notify_one();
// do not use & vars below
RpcSession::join(std::move(session), std::move(setupResult));
});
rpcJoinIfSingleThreaded(thread);
joinCv.wait(lock, [&] { return ownershipTransferred; });
LOG_ALWAYS_FATAL_IF(!ownershipTransferred);
return OK;
}
status_t RpcSession::initShutdownTrigger() {
// first client connection added, but setForServer not called, so
// initializaing for a client.
if (mShutdownTrigger == nullptr) {
mShutdownTrigger = FdTrigger::make();
mEventListener = mShutdownListener = sp<WaitForShutdownListener>::make();
if (mShutdownTrigger == nullptr) return INVALID_OPERATION;
}
return OK;
}
status_t RpcSession::addOutgoingConnection(std::unique_ptr<RpcTransport> rpcTransport, bool init) {
sp<RpcConnection> connection = sp<RpcConnection>::make();
{
RpcMutexLockGuard _l(mMutex);
connection->rpcTransport = std::move(rpcTransport);
connection->exclusiveTid = binder::os::GetThreadId();
mConnections.mOutgoing.push_back(connection);
}
status_t status = OK;
if (init) {
status =
mRpcBinderState->sendConnectionInit(connection, sp<RpcSession>::fromExisting(this));
}
clearConnectionTid(connection);
return status;
}
bool RpcSession::setForServer(const wp<RpcServer>& server, const wp<EventListener>& eventListener,
const std::vector<uint8_t>& sessionId,
const sp<IBinder>& sessionSpecificRoot) {
LOG_ALWAYS_FATAL_IF(mForServer != nullptr);
LOG_ALWAYS_FATAL_IF(server == nullptr);
LOG_ALWAYS_FATAL_IF(mEventListener != nullptr);
LOG_ALWAYS_FATAL_IF(eventListener == nullptr);
LOG_ALWAYS_FATAL_IF(mShutdownTrigger != nullptr);
LOG_ALWAYS_FATAL_IF(mCtx != nullptr);
mShutdownTrigger = FdTrigger::make();
if (mShutdownTrigger == nullptr) return false;
mId = sessionId;
mForServer = server;
mEventListener = eventListener;
mSessionSpecificRootObject = sessionSpecificRoot;
return true;
}
void RpcSession::setSessionSpecificRoot(const sp<IBinder>& sessionSpecificRoot) {
LOG_ALWAYS_FATAL_IF(mSessionSpecificRootObject != nullptr,
"Session specific root object already set");
LOG_ALWAYS_FATAL_IF(mForServer != nullptr,
"Session specific root object cannot be set for a server");
mSessionSpecificRootObject = sessionSpecificRoot;
}
sp<RpcSession::RpcConnection> RpcSession::assignIncomingConnectionToThisThread(
std::unique_ptr<RpcTransport> rpcTransport) {
RpcMutexLockGuard _l(mMutex);
if (mConnections.mIncoming.size() >= mMaxIncomingThreads) {
ALOGE("Cannot add thread to session with %zu threads (max is set to %zu)",
mConnections.mIncoming.size(), mMaxIncomingThreads);
return nullptr;
}
// Don't accept any more connections, some have shutdown. Usually this
// happens when new connections are still being established as part of a
// very short-lived session which shuts down after it already started
// accepting new connections.
if (mConnections.mIncoming.size() < mConnections.mMaxIncoming) {
return nullptr;
}
sp<RpcConnection> session = sp<RpcConnection>::make();
session->rpcTransport = std::move(rpcTransport);
session->exclusiveTid = binder::os::GetThreadId();
mConnections.mIncoming.push_back(session);
mConnections.mMaxIncoming = mConnections.mIncoming.size();
return session;
}
bool RpcSession::removeIncomingConnection(const sp<RpcConnection>& connection) {
RpcMutexUniqueLock _l(mMutex);
if (auto it =
std::find(mConnections.mIncoming.begin(), mConnections.mIncoming.end(), connection);
it != mConnections.mIncoming.end()) {
mConnections.mIncoming.erase(it);
if (mConnections.mIncoming.size() == 0) {
sp<EventListener> listener = mEventListener.promote();
if (listener) {
_l.unlock();
listener->onSessionAllIncomingThreadsEnded(sp<RpcSession>::fromExisting(this));
}
}
return true;
}
return false;
}
void RpcSession::clearConnectionTid(const sp<RpcConnection>& connection) {
RpcMutexUniqueLock _l(mMutex);
connection->exclusiveTid = std::nullopt;
if (mConnections.mWaitingThreads > 0) {
_l.unlock();
mAvailableConnectionCv.notify_one();
}
}
std::vector<uint8_t> RpcSession::getCertificate(RpcCertificateFormat format) {
return mCtx->getCertificate(format);
}
status_t RpcSession::ExclusiveConnection::find(const sp<RpcSession>& session, ConnectionUse use,
ExclusiveConnection* connection) {
connection->mSession = session;
connection->mConnection = nullptr;
connection->mReentrant = false;
uint64_t tid = binder::os::GetThreadId();
RpcMutexUniqueLock _l(session->mMutex);
session->mConnections.mWaitingThreads++;
while (true) {
sp<RpcConnection> exclusive;
sp<RpcConnection> available;
// CHECK FOR DEDICATED CLIENT SOCKET
//
// A server/looper should always use a dedicated connection if available
findConnection(tid, &exclusive, &available, session->mConnections.mOutgoing,
session->mConnections.mOutgoingOffset);
// WARNING: this assumes a server cannot request its client to send
// a transaction, as mIncoming is excluded below.
//
// Imagine we have more than one thread in play, and a single thread
// sends a synchronous, then an asynchronous command. Imagine the
// asynchronous command is sent on the first client connection. Then, if
// we naively send a synchronous command to that same connection, the
// thread on the far side might be busy processing the asynchronous
// command. So, we move to considering the second available thread
// for subsequent calls.
if (use == ConnectionUse::CLIENT_ASYNC && (exclusive != nullptr || available != nullptr)) {
session->mConnections.mOutgoingOffset = (session->mConnections.mOutgoingOffset + 1) %
session->mConnections.mOutgoing.size();
}
// USE SERVING SOCKET (e.g. nested transaction)
if (use != ConnectionUse::CLIENT_ASYNC) {
sp<RpcConnection> exclusiveIncoming;
// server connections are always assigned to a thread
findConnection(tid, &exclusiveIncoming, nullptr /*available*/,
session->mConnections.mIncoming, 0 /* index hint */);
// asynchronous calls cannot be nested, we currently allow ref count
// calls to be nested (so that you can use this without having extra
// threads). Note 'drainCommands' is used so that these ref counts can't
// build up.
if (exclusiveIncoming != nullptr) {
if (exclusiveIncoming->allowNested) {
// guaranteed to be processed as nested command
exclusive = exclusiveIncoming;
} else if (use == ConnectionUse::CLIENT_REFCOUNT && available == nullptr) {
// prefer available socket, but if we don't have one, don't
// wait for one
exclusive = exclusiveIncoming;
}
}
}
// if our thread is already using a connection, prioritize using that
if (exclusive != nullptr) {
connection->mConnection = exclusive;
connection->mReentrant = true;
break;
} else if (available != nullptr) {
connection->mConnection = available;
connection->mConnection->exclusiveTid = tid;
break;
}
if (session->mConnections.mOutgoing.size() == 0) {
ALOGE("Session has no outgoing connections. This is required for an RPC server to make "
"any non-nested (e.g. oneway or on another thread) calls. Use code request "
"reason: %d. Incoming connections: %zu. %s.",
static_cast<int>(use), session->mConnections.mIncoming.size(),
(session->server()
? "This is a server session, so see RpcSession::setMaxIncomingThreads "
"for the corresponding client"
: "This is a client session, so see "
"RpcSession::setMaxOutgoingConnections "
"for this client or RpcServer::setMaxThreads for the corresponding "
"server"));
return WOULD_BLOCK;
}
LOG_RPC_DETAIL("No available connections (have %zu clients and %zu servers). Waiting...",
session->mConnections.mOutgoing.size(),
session->mConnections.mIncoming.size());
session->mAvailableConnectionCv.wait(_l);
}
session->mConnections.mWaitingThreads--;
return OK;
}
void RpcSession::ExclusiveConnection::findConnection(uint64_t tid, sp<RpcConnection>* exclusive,
sp<RpcConnection>* available,
std::vector<sp<RpcConnection>>& sockets,
size_t socketsIndexHint) {
LOG_ALWAYS_FATAL_IF(sockets.size() > 0 && socketsIndexHint >= sockets.size(),
"Bad index %zu >= %zu", socketsIndexHint, sockets.size());
if (*exclusive != nullptr) return; // consistent with break below
for (size_t i = 0; i < sockets.size(); i++) {
sp<RpcConnection>& socket = sockets[(i + socketsIndexHint) % sockets.size()];
// take first available connection (intuition = caching)
if (available && *available == nullptr && socket->exclusiveTid == std::nullopt) {
*available = socket;
continue;
}
// though, prefer to take connection which is already inuse by this thread
// (nested transactions)
if (exclusive && socket->exclusiveTid == tid) {
*exclusive = socket;
break; // consistent with return above
}
}
}
RpcSession::ExclusiveConnection::~ExclusiveConnection() {
// reentrant use of a connection means something less deep in the call stack
// is using this fd, and it retains the right to it. So, we don't give up
// exclusive ownership, and no thread is freed.
if (!mReentrant && mConnection != nullptr) {
mSession->clearConnectionTid(mConnection);
}
}
bool RpcSession::hasActiveConnection(const std::vector<sp<RpcConnection>>& connections) {
for (const auto& connection : connections) {
if (connection->exclusiveTid != std::nullopt && !connection->rpcTransport->isWaiting()) {
return true;
}
}
return false;
}
bool RpcSession::hasActiveRequests() {
RpcMutexUniqueLock _l(mMutex);
if (hasActiveConnection(mConnections.mIncoming)) {
return true;
}
if (hasActiveConnection(mConnections.mOutgoing)) {
return true;
}
return mConnections.mWaitingThreads != 0;
}
} // namespace android