adb: move fdevent implementation out to a separate file. (e62c2c24) · Commits · e / os / android_system_core

adb/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -125,6 +125,7 @@ libadb_srcs = [
		"adb_unique_fd.cpp",
		"adb_utils.cpp",
		"fdevent/fdevent.cpp",
		"fdevent/fdevent_poll.cpp",
		"services.cpp",
		"sockets.cpp",
		"socket_spec.cpp",

adb/fdevent/fdevent.cpp

+18 −525

Original line number	Diff line number	Diff line
		/* http://frotznet.googlecode.com/svn/trunk/utils/fdevent.c
		**
		** Copyright 2006, Brian Swetland <swetland@frotz.net>
		**
		** 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.
		/*
		* Copyright 2006, Brian Swetland <swetland@frotz.net>
		*
		* 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 TRACE_TAG FDEVENT

		#include "sysdeps.h"
		#include "fdevent.h"

		#include <fcntl.h>
		#include <inttypes.h>
		#include <stdint.h>
		#include <stdlib.h>
		#include <string.h>
		#include <unistd.h>

		#include <atomic>
		#include <deque>
		#include <functional>
		#include <list>
		#include <mutex>
		#include <optional>
		#include <unordered_map>
		#include <utility>
		#include <variant>
		#include <vector>

		#include <android-base/chrono_utils.h>
		#include <android-base/file.h>
		#include <android-base/logging.h>
		#include <android-base/stringprintf.h>
		#include <android-base/thread_annotations.h>
		#include <android-base/threads.h>

		#include "adb_io.h"
		#include "adb_trace.h"
		#include "adb_unique_fd.h"
		#include "adb_utils.h"
		#include "sysdeps/chrono.h"

		#define FDE_EVENTMASK 0x00ff
		#define FDE_STATEMASK 0xff00

		#define FDE_ACTIVE 0x0100
		#define FDE_PENDING 0x0200
		#define FDE_CREATED 0x0400
		#include "fdevent.h"
		#include "fdevent_poll.h"

		static std::string dump_fde(const fdevent* fde) {
		std::string dump_fde(const fdevent* fde) {
		std::string state;
		if (fde->state & FDE_ACTIVE) {
		state += "A";
		@@ -82,486 +49,12 @@ static std::string dump_fde(const fdevent* fde) {
		state.c_str());
		}

		struct PollNode {
		fdevent* fde;
		adb_pollfd pollfd;

		explicit PollNode(fdevent* fde) : fde(fde) {
		memset(&pollfd, 0, sizeof(pollfd));
		pollfd.fd = fde->fd.get();

		#if defined(__linux__)
		// Always enable POLLRDHUP, so the host server can take action when some clients disconnect.
		// Then we can avoid leaving many sockets in CLOSE_WAIT state. See http://b/23314034.
		pollfd.events = POLLRDHUP;
		#endif
		}
		};

		struct fdevent_context_poll : public fdevent_context {
		virtual ~fdevent_context_poll() = default;

		virtual fdevent* Create(unique_fd fd, std::variant<fd_func, fd_func2> func, void* arg) final;
		virtual unique_fd Destroy(fdevent* fde) final;

		virtual void Set(fdevent* fde, unsigned events) final;
		virtual void Add(fdevent* fde, unsigned events) final;
		virtual void Del(fdevent* fde, unsigned events) final;
		virtual void SetTimeout(fdevent* fde, std::optional<std::chrono::milliseconds> timeout) final;

		virtual void Loop() final;

		virtual void CheckMainThread() final;

		virtual void Run(std::function<void()> fn) final;

		virtual void TerminateLoop() final;
		virtual size_t InstalledCount() final;
		virtual void Reset() final;

		// All operations to fdevent should happen only in the main thread.
		// That's why we don't need a lock for fdevent.
		std::unordered_map<int, PollNode> poll_node_map_;
		std::list<fdevent*> pending_list_;
		bool main_thread_valid_ = false;
		uint64_t main_thread_id_ = 0;
		uint64_t fdevent_id_ = 0;

		bool run_needs_flush_ = false;
		unique_fd run_queue_notify_fd_;
		std::mutex run_queue_mutex_;
		std::deque<std::function<void()>> run_queue_ GUARDED_BY(run_queue_mutex_);

		std::atomic<bool> terminate_loop_ = false;
		};

		static fdevent_context* g_ambient_fdevent_context = new fdevent_context_poll();

		static fdevent_context* fdevent_get_ambient() {
		return g_ambient_fdevent_context;
		}

		void fdevent_context_poll::CheckMainThread() {
		if (main_thread_valid_) {
		CHECK_EQ(main_thread_id_, android::base::GetThreadId());
		}
		}

		fdevent* fdevent_context_poll::Create(unique_fd fd, std::variant<fd_func, fd_func2> func,
		void* arg) {
		CheckMainThread();
		CHECK_GE(fd.get(), 0);

		fdevent* fde = new fdevent();
		fde->id = fdevent_id_++;
		fde->state = FDE_ACTIVE;
		fde->fd = std::move(fd);
		fde->func = func;
		fde->arg = arg;
		if (!set_file_block_mode(fde->fd, false)) {
		// Here is not proper to handle the error. If it fails here, some error is
		// likely to be detected by poll(), then we can let the callback function
		// to handle it.
		LOG(ERROR) << "failed to set non-blocking mode for fd " << fde->fd.get();
		}
		auto pair = poll_node_map_.emplace(fde->fd.get(), PollNode(fde));
		CHECK(pair.second) << "install existing fd " << fde->fd.get();

		fde->state \|= FDE_CREATED;
		return fde;
		}

		unique_fd fdevent_context_poll::Destroy(fdevent* fde) {
		CheckMainThread();
		if (!fde) {
		return {};
		}

		if (!(fde->state & FDE_CREATED)) {
		LOG(FATAL) << "destroying fde not created by fdevent_create(): " << dump_fde(fde);
		}

		unique_fd result = std::move(fde->fd);
		if (fde->state & FDE_ACTIVE) {
		poll_node_map_.erase(result.get());

		if (fde->state & FDE_PENDING) {
		pending_list_.remove(fde);
		}
		fde->state = 0;
		fde->events = 0;
		}

		delete fde;
		return result;
		}

		void fdevent_context_poll::Set(fdevent* fde, unsigned events) {
		CheckMainThread();
		events &= FDE_EVENTMASK;
		if ((fde->state & FDE_EVENTMASK) == events) {
		return;
		}
		CHECK(fde->state & FDE_ACTIVE);

		auto it = poll_node_map_.find(fde->fd.get());
		CHECK(it != poll_node_map_.end());
		PollNode& node = it->second;
		if (events & FDE_READ) {
		node.pollfd.events \|= POLLIN;
		} else {
		node.pollfd.events &= ~POLLIN;
		}

		if (events & FDE_WRITE) {
		node.pollfd.events \|= POLLOUT;
		} else {
		node.pollfd.events &= ~POLLOUT;
		}
		fde->state = (fde->state & FDE_STATEMASK) \| events;

		D("fdevent_set: %s, events = %u", dump_fde(fde).c_str(), events);

		if (fde->state & FDE_PENDING) {
		// If we are pending, make sure we don't signal an event that is no longer wanted.
		fde->events &= events;
		if (fde->events == 0) {
		pending_list_.remove(fde);
		fde->state &= ~FDE_PENDING;
		}
		}
		}

		void fdevent_context_poll::Add(fdevent* fde, unsigned events) {
		Set(fde, (fde->state & FDE_EVENTMASK) \| events);
		}

		void fdevent_context_poll::Del(fdevent* fde, unsigned events) {
		CHECK(!(events & FDE_TIMEOUT));
		Set(fde, (fde->state & FDE_EVENTMASK) & ~events);
		}

		void fdevent_context_poll::SetTimeout(fdevent* fde,
		std::optional<std::chrono::milliseconds> timeout) {
		CheckMainThread();
		fde->timeout = timeout;
		fde->last_active = std::chrono::steady_clock::now();
		}

		static std::string dump_pollfds(const std::vector<adb_pollfd>& pollfds) {
		std::string result;
		for (const auto& pollfd : pollfds) {
		std::string op;
		if (pollfd.events & POLLIN) {
		op += "R";
		}
		if (pollfd.events & POLLOUT) {
		op += "W";
		}
		android::base::StringAppendF(&result, " %d(%s)", pollfd.fd, op.c_str());
		}
		return result;
		}

		static std::optional<std::chrono::milliseconds> calculate_timeout(fdevent_context_poll* ctx) {
		std::optional<std::chrono::milliseconds> result = std::nullopt;
		auto now = std::chrono::steady_clock::now();
		ctx->CheckMainThread();

		for (const auto& [fd, pollnode] : ctx->poll_node_map_) {
		UNUSED(fd);
		auto timeout_opt = pollnode.fde->timeout;
		if (timeout_opt) {
		auto deadline = pollnode.fde->last_active + *timeout_opt;
		auto time_left = std::chrono::duration_cast<std::chrono::milliseconds>(deadline - now);
		if (time_left < std::chrono::milliseconds::zero()) {
		time_left = std::chrono::milliseconds::zero();
		}

		if (!result) {
		result = time_left;
		} else {
		result = std::min(*result, time_left);
		}
		}
		}

		return result;
		}

		static void fdevent_process(fdevent_context_poll* ctx) {
		std::vector<adb_pollfd> pollfds;
		for (const auto& pair : ctx->poll_node_map_) {
		pollfds.push_back(pair.second.pollfd);
		}
		CHECK_GT(pollfds.size(), 0u);
		D("poll(), pollfds = %s", dump_pollfds(pollfds).c_str());

		auto timeout = calculate_timeout(ctx);
		int timeout_ms;
		if (!timeout) {
		timeout_ms = -1;
		} else {
		timeout_ms = timeout->count();
		}

		int ret = adb_poll(&pollfds[0], pollfds.size(), timeout_ms);
		if (ret == -1) {
		PLOG(ERROR) << "poll(), ret = " << ret;
		return;
		}

		auto post_poll = std::chrono::steady_clock::now();

		for (const auto& pollfd : pollfds) {
		if (pollfd.revents != 0) {
		D("for fd %d, revents = %x", pollfd.fd, pollfd.revents);
		}
		unsigned events = 0;
		if (pollfd.revents & POLLIN) {
		events \|= FDE_READ;
		}
		if (pollfd.revents & POLLOUT) {
		events \|= FDE_WRITE;
		}
		if (pollfd.revents & (POLLERR \| POLLHUP \| POLLNVAL)) {
		// We fake a read, as the rest of the code assumes that errors will
		// be detected at that point.
		events \|= FDE_READ \| FDE_ERROR;
		}
		#if defined(__linux__)
		if (pollfd.revents & POLLRDHUP) {
		events \|= FDE_READ \| FDE_ERROR;
		}
		#endif
		auto it = ctx->poll_node_map_.find(pollfd.fd);
		CHECK(it != ctx->poll_node_map_.end());
		fdevent* fde = it->second.fde;

		if (events == 0) {
		// Check for timeout.
		if (fde->timeout) {
		auto deadline = fde->last_active + *fde->timeout;
		if (deadline < post_poll) {
		events \|= FDE_TIMEOUT;
		}
		}
		}

		if (events != 0) {
		CHECK_EQ(fde->fd.get(), pollfd.fd);
		fde->events \|= events;
		fde->last_active = post_poll;
		D("%s got events %x", dump_fde(fde).c_str(), events);
		fde->state \|= FDE_PENDING;
		ctx->pending_list_.push_back(fde);
		}
		}
		}

		template <class T>
		struct always_false : std::false_type {};

		static void fdevent_call_fdfunc(fdevent* fde) {
		unsigned events = fde->events;
		fde->events = 0;
		CHECK(fde->state & FDE_PENDING);
		fde->state &= (~FDE_PENDING);
		D("fdevent_call_fdfunc %s", dump_fde(fde).c_str());
		std::visit(
		[&](auto&& f) {
		using F = std::decay_t<decltype(f)>;
		if constexpr (std::is_same_v<fd_func, F>) {
		f(fde->fd.get(), events, fde->arg);
		} else if constexpr (std::is_same_v<fd_func2, F>) {
		f(fde, events, fde->arg);
		} else {
		static_assert(always_false<F>::value, "non-exhaustive visitor");
		}
		},
		fde->func);
		}

		static void fdevent_run_flush(fdevent_context_poll* ctx) EXCLUDES(ctx->run_queue_mutex_) {
		// We need to be careful around reentrancy here, since a function we call can queue up another
		// function.
		while (true) {
		std::function<void()> fn;
		{
		std::lock_guard<std::mutex> lock(ctx->run_queue_mutex_);
		if (ctx->run_queue_.empty()) {
		break;
		}
		fn = ctx->run_queue_.front();
		ctx->run_queue_.pop_front();
		}
		fn();
		}
		}

		static void fdevent_run_func(int fd, unsigned ev, void* data) {
		CHECK_GE(fd, 0);
		CHECK(ev & FDE_READ);

		bool* run_needs_flush = static_cast<bool*>(data);
		char buf[1024];

		// Empty the fd.
		if (adb_read(fd, buf, sizeof(buf)) == -1) {
		PLOG(FATAL) << "failed to empty run queue notify fd";
		}

		// Mark that we need to flush, and then run it at the end of fdevent_loop.
		*run_needs_flush = true;
		}

		static void fdevent_run_setup(fdevent_context_poll* ctx) {
		{
		std::lock_guard<std::mutex> lock(ctx->run_queue_mutex_);
		CHECK(ctx->run_queue_notify_fd_.get() == -1);
		int s[2];
		if (adb_socketpair(s) != 0) {
		PLOG(FATAL) << "failed to create run queue notify socketpair";
		}

		if (!set_file_block_mode(s[0], false) \|\| !set_file_block_mode(s[1], false)) {
		PLOG(FATAL) << "failed to make run queue notify socket nonblocking";
		}

		ctx->run_queue_notify_fd_.reset(s[0]);
		fdevent* fde = ctx->Create(unique_fd(s[1]), fdevent_run_func, &ctx->run_needs_flush_);
		CHECK(fde != nullptr);
		ctx->Add(fde, FDE_READ);
		}

		fdevent_run_flush(ctx);
		}

		void fdevent_context_poll::Run(std::function<void()> fn) {
		std::lock_guard<std::mutex> lock(run_queue_mutex_);
		run_queue_.push_back(std::move(fn));

		// run_queue_notify_fd could still be -1 if we're called before fdevent has finished setting up.
		// In that case, rely on the setup code to flush the queue without a notification being needed.
		if (run_queue_notify_fd_ != -1) {
		int rc = adb_write(run_queue_notify_fd_.get(), "", 1);

		// It's possible that we get EAGAIN here, if lots of notifications came in while handling.
		if (rc == 0) {
		PLOG(FATAL) << "run queue notify fd was closed?";
		} else if (rc == -1 && errno != EAGAIN) {
		PLOG(FATAL) << "failed to write to run queue notify fd";
		}
		}
		}

		static void fdevent_check_spin(fdevent_context_poll* ctx, uint64_t cycle) {
		// Check to see if we're spinning because we forgot about an fdevent
		// by keeping track of how long fdevents have been continuously pending.
		struct SpinCheck {
		fdevent* fde;
		android::base::boot_clock::time_point timestamp;
		uint64_t cycle;
		};

		// TODO: Move this into the base fdevent_context.
		static auto& g_continuously_pending = *new std::unordered_map<uint64_t, SpinCheck>();
		static auto last_cycle = android::base::boot_clock::now();

		auto now = android::base::boot_clock::now();
		if (now - last_cycle > 10ms) {
		// We're not spinning.
		g_continuously_pending.clear();
		last_cycle = now;
		return;
		}
		last_cycle = now;

		for (auto* fde : ctx->pending_list_) {
		auto it = g_continuously_pending.find(fde->id);
		if (it == g_continuously_pending.end()) {
		g_continuously_pending[fde->id] =
		SpinCheck{.fde = fde, .timestamp = now, .cycle = cycle};
		} else {
		it->second.cycle = cycle;
		}
		}

		for (auto it = g_continuously_pending.begin(); it != g_continuously_pending.end();) {
		if (it->second.cycle != cycle) {
		it = g_continuously_pending.erase(it);
		} else {
		// Use an absurdly long window, since all we really care about is
		// getting a bugreport eventually.
		if (now - it->second.timestamp > 300s) {
		LOG(FATAL_WITHOUT_ABORT)
		<< "detected spin in fdevent: " << dump_fde(it->second.fde);
		#if defined(__linux__)
		int fd = it->second.fde->fd.get();
		std::string fd_path = android::base::StringPrintf("/proc/self/fd/%d", fd);
		std::string path;
		if (!android::base::Readlink(fd_path, &path)) {
		PLOG(FATAL_WITHOUT_ABORT) << "readlink of fd " << fd << " failed";
		}
		LOG(FATAL_WITHOUT_ABORT) << "fd " << fd << " = " << path;
		#endif
		abort();
		}
		++it;
		}
		}
		}

		void fdevent_context_poll::Loop() {
		this->main_thread_id_ = android::base::GetThreadId();
		this->main_thread_valid_ = true;
		fdevent_run_setup(this);

		uint64_t cycle = 0;
		while (true) {
		if (terminate_loop_) {
		return;
		}

		D("--- --- waiting for events");

		fdevent_process(this);

		fdevent_check_spin(this, cycle++);

		while (!pending_list_.empty()) {
		fdevent* fde = pending_list_.front();
		pending_list_.pop_front();
		fdevent_call_fdfunc(fde);
		}

		if (run_needs_flush_) {
		fdevent_run_flush(this);
		run_needs_flush_ = false;
		}
		}
		}

		void fdevent_context_poll::TerminateLoop() {
		terminate_loop_ = true;
		}

		size_t fdevent_context_poll::InstalledCount() {
		return poll_node_map_.size();
		}

		void fdevent_context_poll::Reset() {
		poll_node_map_.clear();
		pending_list_.clear();

		std::lock_guard<std::mutex> lock(run_queue_mutex_);
		run_queue_notify_fd_.reset();
		run_queue_.clear();

		main_thread_valid_ = false;
		terminate_loop_ = false;
		}

		fdevent* fdevent_create(int fd, fd_func func, void* arg) {
		unique_fd ufd(fd);
		return fdevent_get_ambient()->Create(std::move(ufd), func, arg);

adb/fdevent/fdevent.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -33,10 +33,19 @@
		#define FDE_ERROR 0x0004
		#define FDE_TIMEOUT 0x0008

		// Internal states.
		#define FDE_EVENTMASK 0x00ff
		#define FDE_STATEMASK 0xff00

		#define FDE_ACTIVE 0x0100
		#define FDE_PENDING 0x0200
		#define FDE_CREATED 0x0400

		typedef void (fd_func)(int fd, unsigned events, void userdata);
		typedef void (fd_func2)(struct fdevent fde, unsigned events, void* userdata);

		struct fdevent;
		std::string dump_fde(const fdevent* fde);

		struct fdevent_context {
		virtual ~fdevent_context() = default;

adb/fdevent/fdevent_poll.cpp

0 → 100644

+472 −0

File added.

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adb/fdevent/fdevent_poll.h

0 → 100644

+81 −0

Original line number	Diff line number	Diff line
		#pragma once

		/*
		* Copyright (C) 2019 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 "sysdeps.h"

		#include <deque>
		#include <list>
		#include <mutex>
		#include <unordered_map>

		#include <android-base/thread_annotations.h>

		#include "fdevent.h"

		struct PollNode {
		fdevent* fde;
		adb_pollfd pollfd;

		explicit PollNode(fdevent* fde) : fde(fde) {
		memset(&pollfd, 0, sizeof(pollfd));
		pollfd.fd = fde->fd.get();

		#if defined(__linux__)
		// Always enable POLLRDHUP, so the host server can take action when some clients disconnect.
		// Then we can avoid leaving many sockets in CLOSE_WAIT state. See http://b/23314034.
		pollfd.events = POLLRDHUP;
		#endif
		}
		};

		struct fdevent_context_poll : public fdevent_context {
		virtual ~fdevent_context_poll() = default;

		virtual fdevent* Create(unique_fd fd, std::variant<fd_func, fd_func2> func, void* arg) final;
		virtual unique_fd Destroy(fdevent* fde) final;

		virtual void Set(fdevent* fde, unsigned events) final;
		virtual void Add(fdevent* fde, unsigned events) final;
		virtual void Del(fdevent* fde, unsigned events) final;
		virtual void SetTimeout(fdevent* fde, std::optional<std::chrono::milliseconds> timeout) final;

		virtual void Loop() final;

		virtual void CheckMainThread() final;

		virtual void Run(std::function<void()> fn) final;

		virtual void TerminateLoop() final;
		virtual size_t InstalledCount() final;
		virtual void Reset() final;

		// All operations to fdevent should happen only in the main thread.
		// That's why we don't need a lock for fdevent.
		std::unordered_map<int, PollNode> poll_node_map_;
		std::list<fdevent*> pending_list_;
		bool main_thread_valid_ = false;
		uint64_t main_thread_id_ = 0;
		uint64_t fdevent_id_ = 0;

		bool run_needs_flush_ = false;
		unique_fd run_queue_notify_fd_;
		std::mutex run_queue_mutex_;
		std::deque<std::function<void()>> run_queue_ GUARDED_BY(run_queue_mutex_);

		std::atomic<bool> terminate_loop_ = false;
		};