mirror of
https://github.com/dart-lang/sdk
synced 2024-11-02 12:24:24 +00:00
b2b8e59b28
handler Sockets could be closed from multiple threads (finalizers run during isolate shutdown and the event handler thread). This leads to potential racy behavior. (See https://github.com/dart-lang/sdk/issues/45641) TEST=ci Change-Id: I87900117a4194a71433680f68ed9b6dd31977403 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/209849 Reviewed-by: Ryan Macnak <rmacnak@google.com> Commit-Queue: Siva Annamalai <asiva@google.com>
443 lines
15 KiB
C++
443 lines
15 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#include "platform/globals.h"
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#if defined(DART_HOST_OS_LINUX)
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#include "bin/eventhandler.h"
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#include "bin/eventhandler_linux.h"
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#include <errno.h> // NOLINT
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#include <fcntl.h> // NOLINT
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#include <pthread.h> // NOLINT
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#include <stdio.h> // NOLINT
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#include <string.h> // NOLINT
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#include <sys/epoll.h> // NOLINT
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#include <sys/stat.h> // NOLINT
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#include <sys/timerfd.h> // NOLINT
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#include <unistd.h> // NOLINT
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#include "bin/dartutils.h"
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#include "bin/fdutils.h"
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#include "bin/lockers.h"
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#include "bin/process.h"
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#include "bin/socket.h"
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#include "bin/thread.h"
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#include "platform/syslog.h"
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#include "platform/utils.h"
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namespace dart {
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namespace bin {
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intptr_t DescriptorInfo::GetPollEvents() {
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// Do not ask for EPOLLERR and EPOLLHUP explicitly as they are
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// triggered anyway.
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intptr_t events = 0;
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if ((Mask() & (1 << kInEvent)) != 0) {
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events |= EPOLLIN;
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}
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if ((Mask() & (1 << kOutEvent)) != 0) {
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events |= EPOLLOUT;
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}
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return events;
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}
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// Unregister the file descriptor for a DescriptorInfo structure with
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// epoll.
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static void RemoveFromEpollInstance(intptr_t epoll_fd_, DescriptorInfo* di) {
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VOID_NO_RETRY_EXPECTED(epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, di->fd(), NULL));
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}
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static void AddToEpollInstance(intptr_t epoll_fd_, DescriptorInfo* di) {
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struct epoll_event event;
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event.events = EPOLLRDHUP | di->GetPollEvents();
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if (!di->IsListeningSocket()) {
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event.events |= EPOLLET;
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}
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event.data.ptr = di;
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int status =
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NO_RETRY_EXPECTED(epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, di->fd(), &event));
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if (status == -1) {
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// TODO(dart:io): Verify that the dart end is handling this correctly.
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// Epoll does not accept the file descriptor. It could be due to
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// already closed file descriptor, or unuspported devices, such
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// as /dev/null. In such case, mark the file descriptor as closed,
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// so dart will handle it accordingly.
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di->NotifyAllDartPorts(1 << kCloseEvent);
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}
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}
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EventHandlerImplementation::EventHandlerImplementation()
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: socket_map_(&SimpleHashMap::SamePointerValue, 16) {
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intptr_t result;
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result = NO_RETRY_EXPECTED(pipe(interrupt_fds_));
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if (result != 0) {
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FATAL("Pipe creation failed");
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}
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if (!FDUtils::SetNonBlocking(interrupt_fds_[0])) {
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FATAL("Failed to set pipe fd non blocking\n");
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}
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if (!FDUtils::SetCloseOnExec(interrupt_fds_[0])) {
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FATAL("Failed to set pipe fd close on exec\n");
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}
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if (!FDUtils::SetCloseOnExec(interrupt_fds_[1])) {
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FATAL("Failed to set pipe fd close on exec\n");
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}
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shutdown_ = false;
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// The initial size passed to epoll_create is ignore on newer (>=
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// 2.6.8) Linux versions
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static const int kEpollInitialSize = 64;
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epoll_fd_ = NO_RETRY_EXPECTED(epoll_create(kEpollInitialSize));
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if (epoll_fd_ == -1) {
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FATAL1("Failed creating epoll file descriptor: %i", errno);
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}
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if (!FDUtils::SetCloseOnExec(epoll_fd_)) {
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FATAL("Failed to set epoll fd close on exec\n");
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}
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// Register the interrupt_fd with the epoll instance.
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struct epoll_event event;
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event.events = EPOLLIN;
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event.data.ptr = NULL;
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int status = NO_RETRY_EXPECTED(
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epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, interrupt_fds_[0], &event));
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if (status == -1) {
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FATAL("Failed adding interrupt fd to epoll instance");
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}
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timer_fd_ = NO_RETRY_EXPECTED(timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC));
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if (timer_fd_ == -1) {
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FATAL1("Failed creating timerfd file descriptor: %i", errno);
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}
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// Register the timer_fd_ with the epoll instance.
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event.events = EPOLLIN;
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event.data.fd = timer_fd_;
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status =
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NO_RETRY_EXPECTED(epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &event));
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if (status == -1) {
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FATAL2("Failed adding timerfd fd(%i) to epoll instance: %i", timer_fd_,
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errno);
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}
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}
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static void DeleteDescriptorInfo(void* info) {
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DescriptorInfo* di = reinterpret_cast<DescriptorInfo*>(info);
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di->Close();
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delete di;
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}
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EventHandlerImplementation::~EventHandlerImplementation() {
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socket_map_.Clear(DeleteDescriptorInfo);
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close(epoll_fd_);
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close(timer_fd_);
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close(interrupt_fds_[0]);
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close(interrupt_fds_[1]);
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}
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void EventHandlerImplementation::UpdateEpollInstance(intptr_t old_mask,
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DescriptorInfo* di) {
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intptr_t new_mask = di->Mask();
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if ((old_mask != 0) && (new_mask == 0)) {
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RemoveFromEpollInstance(epoll_fd_, di);
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} else if ((old_mask == 0) && (new_mask != 0)) {
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AddToEpollInstance(epoll_fd_, di);
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} else if ((old_mask != 0) && (new_mask != 0) && (old_mask != new_mask)) {
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ASSERT(!di->IsListeningSocket());
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RemoveFromEpollInstance(epoll_fd_, di);
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AddToEpollInstance(epoll_fd_, di);
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}
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}
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DescriptorInfo* EventHandlerImplementation::GetDescriptorInfo(
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intptr_t fd,
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bool is_listening) {
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ASSERT(fd >= 0);
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SimpleHashMap::Entry* entry = socket_map_.Lookup(
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GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd), true);
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ASSERT(entry != NULL);
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DescriptorInfo* di = reinterpret_cast<DescriptorInfo*>(entry->value);
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if (di == NULL) {
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// If there is no data in the hash map for this file descriptor a
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// new DescriptorInfo for the file descriptor is inserted.
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if (is_listening) {
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di = new DescriptorInfoMultiple(fd);
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} else {
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di = new DescriptorInfoSingle(fd);
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}
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entry->value = di;
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}
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ASSERT(fd == di->fd());
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return di;
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}
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void EventHandlerImplementation::WakeupHandler(intptr_t id,
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Dart_Port dart_port,
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int64_t data) {
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InterruptMessage msg;
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msg.id = id;
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msg.dart_port = dart_port;
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msg.data = data;
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// WriteToBlocking will write up to 512 bytes atomically, and since our msg
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// is smaller than 512, we don't need a thread lock.
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// See: http://linux.die.net/man/7/pipe, section 'Pipe_buf'.
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ASSERT(kInterruptMessageSize < PIPE_BUF);
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intptr_t result =
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FDUtils::WriteToBlocking(interrupt_fds_[1], &msg, kInterruptMessageSize);
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if (result != kInterruptMessageSize) {
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if (result == -1) {
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perror("Interrupt message failure:");
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}
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FATAL1("Interrupt message failure. Wrote %" Pd " bytes.", result);
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}
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}
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void EventHandlerImplementation::HandleInterruptFd() {
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const intptr_t MAX_MESSAGES = kInterruptMessageSize;
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InterruptMessage msg[MAX_MESSAGES];
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ssize_t bytes = TEMP_FAILURE_RETRY_NO_SIGNAL_BLOCKER(
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read(interrupt_fds_[0], msg, MAX_MESSAGES * kInterruptMessageSize));
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for (ssize_t i = 0; i < bytes / kInterruptMessageSize; i++) {
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if (msg[i].id == kTimerId) {
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timeout_queue_.UpdateTimeout(msg[i].dart_port, msg[i].data);
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UpdateTimerFd();
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} else if (msg[i].id == kShutdownId) {
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shutdown_ = true;
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} else {
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ASSERT((msg[i].data & COMMAND_MASK) != 0);
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Socket* socket = reinterpret_cast<Socket*>(msg[i].id);
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RefCntReleaseScope<Socket> rs(socket);
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if (socket->fd() == -1) {
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continue;
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}
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DescriptorInfo* di =
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GetDescriptorInfo(socket->fd(), IS_LISTENING_SOCKET(msg[i].data));
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if (IS_COMMAND(msg[i].data, kShutdownReadCommand)) {
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ASSERT(!di->IsListeningSocket());
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// Close the socket for reading.
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VOID_NO_RETRY_EXPECTED(shutdown(di->fd(), SHUT_RD));
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} else if (IS_COMMAND(msg[i].data, kShutdownWriteCommand)) {
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ASSERT(!di->IsListeningSocket());
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// Close the socket for writing.
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VOID_NO_RETRY_EXPECTED(shutdown(di->fd(), SHUT_WR));
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} else if (IS_COMMAND(msg[i].data, kCloseCommand)) {
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// Close the socket and free system resources and move on to next
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// message.
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if (IS_SIGNAL_SOCKET(msg[i].data)) {
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Process::ClearSignalHandlerByFd(di->fd(), socket->isolate_port());
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}
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intptr_t old_mask = di->Mask();
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Dart_Port port = msg[i].dart_port;
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if (port != ILLEGAL_PORT) {
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di->RemovePort(port);
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}
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intptr_t new_mask = di->Mask();
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UpdateEpollInstance(old_mask, di);
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intptr_t fd = di->fd();
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ASSERT(fd == socket->fd());
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if (di->IsListeningSocket()) {
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// We only close the socket file descriptor from the operating
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// system if there are no other dart socket objects which
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// are listening on the same (address, port) combination.
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ListeningSocketRegistry* registry =
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ListeningSocketRegistry::Instance();
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MutexLocker locker(registry->mutex());
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if (registry->CloseSafe(socket)) {
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ASSERT(new_mask == 0);
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socket_map_.Remove(GetHashmapKeyFromFd(fd),
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GetHashmapHashFromFd(fd));
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di->Close();
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delete di;
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}
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socket->CloseFd();
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} else {
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ASSERT(new_mask == 0);
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socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
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di->Close();
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delete di;
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socket->CloseFd();
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}
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DartUtils::PostInt32(port, 1 << kDestroyedEvent);
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} else if (IS_COMMAND(msg[i].data, kReturnTokenCommand)) {
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int count = TOKEN_COUNT(msg[i].data);
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intptr_t old_mask = di->Mask();
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di->ReturnTokens(msg[i].dart_port, count);
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UpdateEpollInstance(old_mask, di);
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} else if (IS_COMMAND(msg[i].data, kSetEventMaskCommand)) {
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// `events` can only have kInEvent/kOutEvent flags set.
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intptr_t events = msg[i].data & EVENT_MASK;
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ASSERT(0 == (events & ~(1 << kInEvent | 1 << kOutEvent)));
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intptr_t old_mask = di->Mask();
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di->SetPortAndMask(msg[i].dart_port, msg[i].data & EVENT_MASK);
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UpdateEpollInstance(old_mask, di);
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} else {
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UNREACHABLE();
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}
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}
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}
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}
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void EventHandlerImplementation::UpdateTimerFd() {
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struct itimerspec it;
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memset(&it, 0, sizeof(it));
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if (timeout_queue_.HasTimeout()) {
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int64_t millis = timeout_queue_.CurrentTimeout();
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it.it_value.tv_sec = millis / 1000;
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it.it_value.tv_nsec = (millis % 1000) * 1000000;
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}
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VOID_NO_RETRY_EXPECTED(
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timerfd_settime(timer_fd_, TFD_TIMER_ABSTIME, &it, NULL));
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}
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#ifdef DEBUG_POLL
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static void PrintEventMask(intptr_t fd, intptr_t events) {
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Syslog::Print("%d ", fd);
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if ((events & EPOLLIN) != 0) {
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Syslog::Print("EPOLLIN ");
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}
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if ((events & EPOLLPRI) != 0) {
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Syslog::Print("EPOLLPRI ");
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}
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if ((events & EPOLLOUT) != 0) {
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Syslog::Print("EPOLLOUT ");
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}
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if ((events & EPOLLERR) != 0) {
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Syslog::Print("EPOLLERR ");
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}
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if ((events & EPOLLHUP) != 0) {
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Syslog::Print("EPOLLHUP ");
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}
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if ((events & EPOLLRDHUP) != 0) {
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Syslog::Print("EPOLLRDHUP ");
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}
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int all_events =
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EPOLLIN | EPOLLPRI | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDHUP;
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if ((events & ~all_events) != 0) {
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Syslog::Print("(and %08x) ", events & ~all_events);
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}
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Syslog::Print("(available %d) ", FDUtils::AvailableBytes(fd));
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Syslog::Print("\n");
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}
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#endif
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intptr_t EventHandlerImplementation::GetPollEvents(intptr_t events,
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DescriptorInfo* di) {
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#ifdef DEBUG_POLL
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PrintEventMask(di->fd(), events);
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#endif
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if ((events & EPOLLERR) != 0) {
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// Return error only if EPOLLIN is present.
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return ((events & EPOLLIN) != 0) ? (1 << kErrorEvent) : 0;
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}
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intptr_t event_mask = 0;
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if ((events & EPOLLIN) != 0) {
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event_mask |= (1 << kInEvent);
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}
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if ((events & EPOLLOUT) != 0) {
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event_mask |= (1 << kOutEvent);
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}
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if ((events & (EPOLLHUP | EPOLLRDHUP)) != 0) {
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event_mask |= (1 << kCloseEvent);
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}
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return event_mask;
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}
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void EventHandlerImplementation::HandleEvents(struct epoll_event* events,
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int size) {
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bool interrupt_seen = false;
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for (int i = 0; i < size; i++) {
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if (events[i].data.ptr == NULL) {
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interrupt_seen = true;
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} else if (events[i].data.fd == timer_fd_) {
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int64_t val;
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VOID_TEMP_FAILURE_RETRY_NO_SIGNAL_BLOCKER(
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read(timer_fd_, &val, sizeof(val)));
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if (timeout_queue_.HasTimeout()) {
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DartUtils::PostNull(timeout_queue_.CurrentPort());
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timeout_queue_.RemoveCurrent();
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}
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UpdateTimerFd();
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} else {
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DescriptorInfo* di =
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reinterpret_cast<DescriptorInfo*>(events[i].data.ptr);
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const intptr_t old_mask = di->Mask();
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const intptr_t event_mask = GetPollEvents(events[i].events, di);
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if ((event_mask & (1 << kErrorEvent)) != 0) {
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di->NotifyAllDartPorts(event_mask);
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UpdateEpollInstance(old_mask, di);
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} else if (event_mask != 0) {
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Dart_Port port = di->NextNotifyDartPort(event_mask);
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ASSERT(port != 0);
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UpdateEpollInstance(old_mask, di);
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DartUtils::PostInt32(port, event_mask);
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}
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}
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}
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if (interrupt_seen) {
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// Handle after socket events, so we avoid closing a socket before we handle
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// the current events.
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HandleInterruptFd();
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}
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}
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void EventHandlerImplementation::Poll(uword args) {
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ThreadSignalBlocker signal_blocker(SIGPROF);
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static const intptr_t kMaxEvents = 16;
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struct epoll_event events[kMaxEvents];
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EventHandler* handler = reinterpret_cast<EventHandler*>(args);
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EventHandlerImplementation* handler_impl = &handler->delegate_;
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ASSERT(handler_impl != NULL);
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while (!handler_impl->shutdown_) {
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intptr_t result = TEMP_FAILURE_RETRY_NO_SIGNAL_BLOCKER(
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epoll_wait(handler_impl->epoll_fd_, events, kMaxEvents, -1));
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ASSERT(EAGAIN == EWOULDBLOCK);
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if (result <= 0) {
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if (errno != EWOULDBLOCK) {
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perror("Poll failed");
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}
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} else {
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handler_impl->HandleEvents(events, result);
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}
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}
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DEBUG_ASSERT(ReferenceCounted<Socket>::instances() == 0);
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handler->NotifyShutdownDone();
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}
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void EventHandlerImplementation::Start(EventHandler* handler) {
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int result =
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Thread::Start("dart:io EventHandler", &EventHandlerImplementation::Poll,
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reinterpret_cast<uword>(handler));
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if (result != 0) {
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FATAL1("Failed to start event handler thread %d", result);
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}
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}
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void EventHandlerImplementation::Shutdown() {
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SendData(kShutdownId, 0, 0);
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}
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void EventHandlerImplementation::SendData(intptr_t id,
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Dart_Port dart_port,
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int64_t data) {
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WakeupHandler(id, dart_port, data);
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}
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void* EventHandlerImplementation::GetHashmapKeyFromFd(intptr_t fd) {
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// The hashmap does not support keys with value 0.
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return reinterpret_cast<void*>(fd + 1);
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}
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uint32_t EventHandlerImplementation::GetHashmapHashFromFd(intptr_t fd) {
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// The hashmap does not support keys with value 0.
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return dart::Utils::WordHash(fd + 1);
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}
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} // namespace bin
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} // namespace dart
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#endif // defined(DART_HOST_OS_LINUX)
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