binder: Eliminate a data copy in RPC transport operations (a39e4ede) · Commits · e / os / platform_frameworks_native

libs/binder/RpcServer.cpp

+7 −6

Original line number	Diff line number	Diff line
		@@ -287,8 +287,8 @@ void RpcServer::establishConnection(sp<RpcServer>&& server, base::unique_fd clie

		RpcConnectionHeader header;
		if (status == OK) {
		status = client->interruptableReadFully(server->mShutdownTrigger.get(), &header,
		sizeof(header), {});
		iovec iov{&header, sizeof(header)};
		status = client->interruptableReadFully(server->mShutdownTrigger.get(), &iov, 1, {});
		if (status != OK) {
		ALOGE("Failed to read ID for client connecting to RPC server: %s",
		statusToString(status).c_str());
		@@ -301,8 +301,9 @@ void RpcServer::establishConnection(sp<RpcServer>&& server, base::unique_fd clie
		if (header.sessionIdSize > 0) {
		if (header.sessionIdSize == kSessionIdBytes) {
		sessionId.resize(header.sessionIdSize);
		status = client->interruptableReadFully(server->mShutdownTrigger.get(),
		sessionId.data(), sessionId.size(), {});
		iovec iov{sessionId.data(), sessionId.size()};
		status =
		client->interruptableReadFully(server->mShutdownTrigger.get(), &iov, 1, {});
		if (status != OK) {
		ALOGE("Failed to read session ID for client connecting to RPC server: %s",
		statusToString(status).c_str());
		@@ -331,8 +332,8 @@ void RpcServer::establishConnection(sp<RpcServer>&& server, base::unique_fd clie
		.version = protocolVersion,
		};

		status = client->interruptableWriteFully(server->mShutdownTrigger.get(), &response,
		sizeof(response), {});
		iovec iov{&response, sizeof(response)};
		status = client->interruptableWriteFully(server->mShutdownTrigger.get(), &iov, 1, {});
		if (status != OK) {
		ALOGE("Failed to send new session response: %s", statusToString(status).c_str());
		// still need to cleanup before we can return

libs/binder/RpcSession.cpp

+5 −3

Original line number	Diff line number	Diff line
		@@ -615,8 +615,9 @@ status_t RpcSession::initAndAddConnection(unique_fd fd, const std::vector<uint8_
		header.options \|= RPC_CONNECTION_OPTION_INCOMING;
		}

		iovec headerIov{&header, sizeof(header)};
		auto sendHeaderStatus =
		server->interruptableWriteFully(mShutdownTrigger.get(), &header, sizeof(header), {});
		server->interruptableWriteFully(mShutdownTrigger.get(), &headerIov, 1, {});
		if (sendHeaderStatus != OK) {
		ALOGE("Could not write connection header to socket: %s",
		statusToString(sendHeaderStatus).c_str());
		@@ -624,9 +625,10 @@ status_t RpcSession::initAndAddConnection(unique_fd fd, const std::vector<uint8_
		}

		if (sessionId.size() > 0) {
		iovec sessionIov{const_cast<void>(static_cast<const void>(sessionId.data())),
		sessionId.size()};
		auto sendSessionIdStatus =
		server->interruptableWriteFully(mShutdownTrigger.get(), sessionId.data(),
		sessionId.size(), {});
		server->interruptableWriteFully(mShutdownTrigger.get(), &sessionIov, 1, {});
		if (sendSessionIdStatus != OK) {
		ALOGE("Could not write session ID ('%s') to socket: %s",
		base::HexString(sessionId.data(), sessionId.size()).c_str(),

libs/binder/RpcState.cpp

+47 −68

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@
		#include "RpcState.h"

		#include <android-base/hex.h>
		#include <android-base/macros.h>
		#include <android-base/scopeguard.h>
		#include <binder/BpBinder.h>
		#include <binder/IPCThreadState.h>
		@@ -309,22 +310,18 @@ RpcState::CommandData::CommandData(size_t size) : mSize(size) {
		}

		status_t RpcState::rpcSend(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session, const char* what, const void* data,
		size_t size, const std::function<status_t()>& altPoll) {
		const sp<RpcSession>& session, const char* what, iovec* iovs,
		size_t niovs, const std::function<status_t()>& altPoll) {
		for (size_t i = 0; i < niovs; i++) {
		LOG_RPC_DETAIL("Sending %s on RpcTransport %p: %s", what, connection->rpcTransport.get(),
		android::base::HexString(data, size).c_str());

		if (size > std::numeric_limits<ssize_t>::max()) {
		ALOGE("Cannot send %s at size %zu (too big)", what, size);
		(void)session->shutdownAndWait(false);
		return BAD_VALUE;
		android::base::HexString(iovs[i].iov_base, iovs[i].iov_len).c_str());
		}

		if (status_t status =
		connection->rpcTransport->interruptableWriteFully(session->mShutdownTrigger.get(),
		data, size, altPoll);
		iovs, niovs, altPoll);
		status != OK) {
		LOG_RPC_DETAIL("Failed to write %s (%zu bytes) on RpcTransport %p, error: %s", what, size,
		LOG_RPC_DETAIL("Failed to write %s (%zu iovs) on RpcTransport %p, error: %s", what, niovs,
		connection->rpcTransport.get(), statusToString(status).c_str());
		(void)session->shutdownAndWait(false);
		return status;
		@@ -334,34 +331,30 @@ status_t RpcState::rpcSend(const sp<RpcSession::RpcConnection>& connection,
		}

		status_t RpcState::rpcRec(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session, const char* what, void* data,
		size_t size) {
		if (size > std::numeric_limits<ssize_t>::max()) {
		ALOGE("Cannot rec %s at size %zu (too big)", what, size);
		(void)session->shutdownAndWait(false);
		return BAD_VALUE;
		}

		const sp<RpcSession>& session, const char* what, iovec* iovs,
		size_t niovs) {
		if (status_t status =
		connection->rpcTransport->interruptableReadFully(session->mShutdownTrigger.get(),
		data, size, {});
		iovs, niovs, {});
		status != OK) {
		LOG_RPC_DETAIL("Failed to read %s (%zu bytes) on RpcTransport %p, error: %s", what, size,
		LOG_RPC_DETAIL("Failed to read %s (%zu iovs) on RpcTransport %p, error: %s", what, niovs,
		connection->rpcTransport.get(), statusToString(status).c_str());
		(void)session->shutdownAndWait(false);
		return status;
		}

		for (size_t i = 0; i < niovs; i++) {
		LOG_RPC_DETAIL("Received %s on RpcTransport %p: %s", what, connection->rpcTransport.get(),
		android::base::HexString(data, size).c_str());
		android::base::HexString(iovs[i].iov_base, iovs[i].iov_len).c_str());
		}
		return OK;
		}

		status_t RpcState::readNewSessionResponse(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session, uint32_t* version) {
		RpcNewSessionResponse response;
		if (status_t status =
		rpcRec(connection, session, "new session response", &response, sizeof(response));
		iovec iov{&response, sizeof(response)};
		if (status_t status = rpcRec(connection, session, "new session response", &iov, 1);
		status != OK) {
		return status;
		}
		@@ -374,14 +367,15 @@ status_t RpcState::sendConnectionInit(const sp<RpcSession::RpcConnection>& conne
		RpcOutgoingConnectionInit init{
		.msg = RPC_CONNECTION_INIT_OKAY,
		};
		return rpcSend(connection, session, "connection init", &init, sizeof(init));
		iovec iov{&init, sizeof(init)};
		return rpcSend(connection, session, "connection init", &iov, 1);
		}

		status_t RpcState::readConnectionInit(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session) {
		RpcOutgoingConnectionInit init;
		if (status_t status = rpcRec(connection, session, "connection init", &init, sizeof(init));
		status != OK)
		iovec iov{&init, sizeof(init)};
		if (status_t status = rpcRec(connection, session, "connection init", &iov, 1); status != OK)
		return status;

		static_assert(sizeof(init.msg) == sizeof(RPC_CONNECTION_INIT_OKAY));
		@@ -514,17 +508,6 @@ status_t RpcState::transactAddress(const sp<RpcSession::RpcConnection>& connecti
		.flags = flags,
		.asyncNumber = asyncNumber,
		};
		CommandData transactionData(sizeof(RpcWireHeader) + sizeof(RpcWireTransaction) +
		data.dataSize());
		if (!transactionData.valid()) {
		return NO_MEMORY;
		}

		memcpy(transactionData.data() + 0, &command, sizeof(RpcWireHeader));
		memcpy(transactionData.data() + sizeof(RpcWireHeader), &transaction,
		sizeof(RpcWireTransaction));
		memcpy(transactionData.data() + sizeof(RpcWireHeader) + sizeof(RpcWireTransaction), data.data(),
		data.dataSize());

		constexpr size_t kWaitMaxUs = 1000000;
		constexpr size_t kWaitLogUs = 10000;
		@@ -550,8 +533,13 @@ status_t RpcState::transactAddress(const sp<RpcSession::RpcConnection>& connecti
		return drainCommands(connection, session, CommandType::CONTROL_ONLY);
		};

		if (status_t status = rpcSend(connection, session, "transaction", transactionData.data(),
		transactionData.size(), drainRefs);
		iovec iovs[]{
		{&command, sizeof(RpcWireHeader)},
		{&transaction, sizeof(RpcWireTransaction)},
		{const_cast<uint8_t*>(data.data()), data.dataSize()},
		};
		if (status_t status =
		rpcSend(connection, session, "transaction", iovs, arraysize(iovs), drainRefs);
		status != OK) {
		// TODO(b/167966510): need to undo onBinderLeaving - we know the
		// refcount isn't successfully transferred.
		@@ -584,8 +572,8 @@ status_t RpcState::waitForReply(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session, Parcel* reply) {
		RpcWireHeader command;
		while (true) {
		if (status_t status = rpcRec(connection, session, "command header (for reply)", &command,
		sizeof(command));
		iovec iov{&command, sizeof(command)};
		if (status_t status = rpcRec(connection, session, "command header (for reply)", &iov, 1);
		status != OK)
		return status;

		@@ -599,8 +587,8 @@ status_t RpcState::waitForReply(const sp<RpcSession::RpcConnection>& connection,
		CommandData data(command.bodySize);
		if (!data.valid()) return NO_MEMORY;

		if (status_t status = rpcRec(connection, session, "reply body", data.data(), command.bodySize);
		status != OK)
		iovec iov{data.data(), command.bodySize};
		if (status_t status = rpcRec(connection, session, "reply body", &iov, 1); status != OK)
		return status;

		if (command.bodySize < sizeof(RpcWireReply)) {
		@@ -653,11 +641,8 @@ status_t RpcState::sendDecStrongToTarget(const sp<RpcSession::RpcConnection>& co
		.command = RPC_COMMAND_DEC_STRONG,
		.bodySize = sizeof(RpcDecStrong),
		};
		if (status_t status = rpcSend(connection, session, "dec ref header", &cmd, sizeof(cmd));
		status != OK)
		return status;

		return rpcSend(connection, session, "dec ref body", &body, sizeof(body));
		iovec iovs[]{{&cmd, sizeof(cmd)}, {&body, sizeof(body)}};
		return rpcSend(connection, session, "dec ref", iovs, arraysize(iovs));
		}

		status_t RpcState::getAndExecuteCommand(const sp<RpcSession::RpcConnection>& connection,
		@@ -665,8 +650,8 @@ status_t RpcState::getAndExecuteCommand(const sp<RpcSession::RpcConnection>& con
		LOG_RPC_DETAIL("getAndExecuteCommand on RpcTransport %p", connection->rpcTransport.get());

		RpcWireHeader command;
		if (status_t status = rpcRec(connection, session, "command header (for server)", &command,
		sizeof(command));
		iovec iov{&command, sizeof(command)};
		if (status_t status = rpcRec(connection, session, "command header (for server)", &iov, 1);
		status != OK)
		return status;

		@@ -726,9 +711,8 @@ status_t RpcState::processTransact(const sp<RpcSession::RpcConnection>& connecti
		if (!transactionData.valid()) {
		return NO_MEMORY;
		}
		if (status_t status = rpcRec(connection, session, "transaction body", transactionData.data(),
		transactionData.size());
		status != OK)
		iovec iov{transactionData.data(), transactionData.size()};
		if (status_t status = rpcRec(connection, session, "transaction body", &iov, 1); status != OK)
		return status;

		return processTransactInternal(connection, session, std::move(transactionData));
		@@ -965,16 +949,12 @@ processTransactInternalTailCall:
		.status = replyStatus,
		};

		CommandData replyData(sizeof(RpcWireHeader) + sizeof(RpcWireReply) + reply.dataSize());
		if (!replyData.valid()) {
		return NO_MEMORY;
		}
		memcpy(replyData.data() + 0, &cmdReply, sizeof(RpcWireHeader));
		memcpy(replyData.data() + sizeof(RpcWireHeader), &rpcReply, sizeof(RpcWireReply));
		memcpy(replyData.data() + sizeof(RpcWireHeader) + sizeof(RpcWireReply), reply.data(),
		reply.dataSize());

		return rpcSend(connection, session, "reply", replyData.data(), replyData.size());
		iovec iovs[]{
		{&cmdReply, sizeof(RpcWireHeader)},
		{&rpcReply, sizeof(RpcWireReply)},
		{const_cast<uint8_t*>(reply.data()), reply.dataSize()},
		};
		return rpcSend(connection, session, "reply", iovs, arraysize(iovs));
		}

		status_t RpcState::processDecStrong(const sp<RpcSession::RpcConnection>& connection,
		@@ -985,9 +965,8 @@ status_t RpcState::processDecStrong(const sp<RpcSession::RpcConnection>& connect
		if (!commandData.valid()) {
		return NO_MEMORY;
		}
		if (status_t status =
		rpcRec(connection, session, "dec ref body", commandData.data(), commandData.size());
		status != OK)
		iovec iov{commandData.data(), commandData.size()};
		if (status_t status = rpcRec(connection, session, "dec ref body", &iov, 1); status != OK)
		return status;

		if (command.bodySize != sizeof(RpcDecStrong)) {

libs/binder/RpcState.h

+6 −4

Original line number	Diff line number	Diff line
		@@ -24,6 +24,8 @@
		#include <optional>
		#include <queue>

		#include <sys/uio.h>

		namespace android {

		struct RpcWireHeader;
		@@ -177,12 +179,12 @@ private:
		};

		[[nodiscard]] status_t rpcSend(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session, const char* what,
		const void* data, size_t size,
		const sp<RpcSession>& session, const char* what, iovec* iovs,
		size_t niovs,
		const std::function<status_t()>& altPoll = nullptr);
		[[nodiscard]] status_t rpcRec(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session, const char* what, void* data,
		size_t size);
		const sp<RpcSession>& session, const char* what, iovec* iovs,
		size_t niovs);

		[[nodiscard]] status_t waitForReply(const sp<RpcSession::RpcConnection>& connection,
		const sp<RpcSession>& session, Parcel* reply);

libs/binder/RpcTransportRaw.cpp

+49 −16

Original line number	Diff line number	Diff line
		@@ -43,12 +43,10 @@ public:
		return ret;
		}

		template <typename Buffer, typename SendOrReceive>
		status_t interruptableReadOrWrite(FdTrigger* fdTrigger, Buffer buffer, size_t size,
		template <typename SendOrReceive>
		status_t interruptableReadOrWrite(FdTrigger* fdTrigger, iovec* iovs, size_t niovs,
		SendOrReceive sendOrReceiveFun, const char* funName,
		int16_t event, const std::function<status_t()>& altPoll) {
		const Buffer end = buffer + size;

		MAYBE_WAIT_IN_FLAKE_MODE;

		// Since we didn't poll, we need to manually check to see if it was triggered. Otherwise, we
		@@ -57,26 +55,61 @@ public:
		return DEAD_OBJECT;
		}

		// If iovs has one or more empty vectors at the end and
		// we somehow advance past all the preceding vectors and
		// pass some or all of the empty ones to sendmsg/recvmsg,
		// the call will return processSize == 0. In that case
		// we should be returning OK but instead return DEAD_OBJECT.
		// To avoid this problem, we make sure here that the last
		// vector at iovs[niovs - 1] has a non-zero length.
		while (niovs > 0 && iovs[niovs - 1].iov_len == 0) {
		niovs--;
		}
		if (niovs == 0) {
		// The vectors are all empty, so we have nothing to send.
		return OK;
		}

		bool havePolled = false;
		while (true) {
		ssize_t processSize = TEMP_FAILURE_RETRY(
		sendOrReceiveFun(mSocket.get(), buffer, end - buffer, MSG_NOSIGNAL));
		msghdr msg{
		.msg_iov = iovs,
		.msg_iovlen = niovs,
		};
		ssize_t processSize =
		TEMP_FAILURE_RETRY(sendOrReceiveFun(mSocket.get(), &msg, MSG_NOSIGNAL));

		if (processSize < 0) {
		int savedErrno = errno;

		// Still return the error on later passes, since it would expose
		// a problem with polling
		if (havePolled \|\|
		(!havePolled && savedErrno != EAGAIN && savedErrno != EWOULDBLOCK)) {
		if (havePolled \|\| (savedErrno != EAGAIN && savedErrno != EWOULDBLOCK)) {
		LOG_RPC_DETAIL("RpcTransport %s(): %s", funName, strerror(savedErrno));
		return -savedErrno;
		}
		} else if (processSize == 0) {
		return DEAD_OBJECT;
		} else {
		buffer += processSize;
		if (buffer == end) {
		while (processSize > 0 && niovs > 0) {
		auto& iov = iovs[0];
		if (static_cast<size_t>(processSize) < iov.iov_len) {
		// Advance the base of the current iovec
		iov.iov_base = reinterpret_cast<char*>(iov.iov_base) + processSize;
		iov.iov_len -= processSize;
		break;
		}

		// The current iovec was fully written
		processSize -= iov.iov_len;
		iovs++;
		niovs--;
		}
		if (niovs == 0) {
		LOG_ALWAYS_FATAL_IF(processSize > 0,
		"Reached the end of iovecs "
		"with %zd bytes remaining",
		processSize);
		return OK;
		}
		}
		@@ -95,16 +128,16 @@ public:
		}
		}

		status_t interruptableWriteFully(FdTrigger* fdTrigger, const void* data, size_t size,
		status_t interruptableWriteFully(FdTrigger* fdTrigger, iovec* iovs, size_t niovs,
		const std::function<status_t()>& altPoll) override {
		return interruptableReadOrWrite(fdTrigger, reinterpret_cast<const uint8_t*>(data), size,
		send, "send", POLLOUT, altPoll);
		return interruptableReadOrWrite(fdTrigger, iovs, niovs, sendmsg, "sendmsg", POLLOUT,
		altPoll);
		}

		status_t interruptableReadFully(FdTrigger* fdTrigger, void* data, size_t size,
		status_t interruptableReadFully(FdTrigger* fdTrigger, iovec* iovs, size_t niovs,
		const std::function<status_t()>& altPoll) override {
		return interruptableReadOrWrite(fdTrigger, reinterpret_cast<uint8_t*>(data), size, recv,
		"recv", POLLIN, altPoll);
		return interruptableReadOrWrite(fdTrigger, iovs, niovs, recvmsg, "recvmsg", POLLIN,
		altPoll);
		}

		private: