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webrtc/rtc_base/physical_socket_server.cc
Taylor Brandstetter 7b69a44c8b Fix ABA problem when iterating epoll events. 
Original patch contributed by andrey.semashev@gmail.com.

In PhysicalSocketServer::WaitEpoll(), the loop verifies that the
signalled dispatcher is in dispatchers_ set. It does so by looking up
the dispatcher pointer in the set. This is vulnerable to the ABA
problem because one dispatcher may be removed and destroyed and another
created and added with the same address before epoll reports an event
for the old dispatcher. The same issue exists for other Wait
implementations, if a dispatcher is removed and a new one added with
the same socket handle is the old.

This is avoided by using a 64-bit key for looking up the dispatcher
in the set. The key is set from a running counter which gets incremented
when a dispatcher is added to the set, so even if the same dispatcher
pointer is added, removed and added again, the key value will be
different.

This changes the storage of dispatchers_ from a set to a flat_hash_map,
which uses a bit more memory but has faster lookup (O(1) as opposed to
O(log n)).

Bug: webrtc:11124
Change-Id: I6d206e1a367b58ba971edca9b48af7664384b797
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/181027
Commit-Queue: Taylor <deadbeef@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32019}
2020-08-31 20:26:37 +00:00

1733 lines
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/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/physical_socket_server.h"
#if defined(_MSC_VER) && _MSC_VER < 1300
#pragma warning(disable : 4786)
#endif
#ifdef MEMORY_SANITIZER
#include <sanitizer/msan_interface.h>
#endif
#if defined(WEBRTC_POSIX)
#include <fcntl.h>
#include <string.h>
#if defined(WEBRTC_USE_EPOLL)
// "poll" will be used to wait for the signal dispatcher.
#include <poll.h>
#endif
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/time.h>
#include <unistd.h>
#endif
#if defined(WEBRTC_WIN)
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#undef SetPort
#endif
#include <errno.h>
#include <algorithm>
#include <map>
#include "rtc_base/arraysize.h"
#include "rtc_base/byte_order.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/network_monitor.h"
#include "rtc_base/null_socket_server.h"
#include "rtc_base/time_utils.h"
#if defined(WEBRTC_LINUX)
#include <linux/sockios.h>
#endif
#if defined(WEBRTC_WIN)
#define LAST_SYSTEM_ERROR (::GetLastError())
#elif defined(__native_client__) && __native_client__
#define LAST_SYSTEM_ERROR (0)
#elif defined(WEBRTC_POSIX)
#define LAST_SYSTEM_ERROR (errno)
#endif // WEBRTC_WIN
#if defined(WEBRTC_POSIX)
#include <netinet/tcp.h> // for TCP_NODELAY
#define IP_MTU 14 // Until this is integrated from linux/in.h to netinet/in.h
typedef void* SockOptArg;
#endif // WEBRTC_POSIX
#if defined(WEBRTC_POSIX) && !defined(WEBRTC_MAC) && !defined(__native_client__)
int64_t GetSocketRecvTimestamp(int socket) {
struct timeval tv_ioctl;
int ret = ioctl(socket, SIOCGSTAMP, &tv_ioctl);
if (ret != 0)
return -1;
int64_t timestamp =
rtc::kNumMicrosecsPerSec * static_cast<int64_t>(tv_ioctl.tv_sec) +
static_cast<int64_t>(tv_ioctl.tv_usec);
return timestamp;
}
#else
int64_t GetSocketRecvTimestamp(int socket) {
return -1;
}
#endif
#if defined(WEBRTC_WIN)
typedef char* SockOptArg;
#endif
#if defined(WEBRTC_USE_EPOLL)
// POLLRDHUP / EPOLLRDHUP are only defined starting with Linux 2.6.17.
#if !defined(POLLRDHUP)
#define POLLRDHUP 0x2000
#endif
#if !defined(EPOLLRDHUP)
#define EPOLLRDHUP 0x2000
#endif
#endif
namespace {
class ScopedSetTrue {
public:
ScopedSetTrue(bool* value) : value_(value) {
RTC_DCHECK(!*value_);
*value_ = true;
}
~ScopedSetTrue() { *value_ = false; }
private:
bool* value_;
};
} // namespace
namespace rtc {
std::unique_ptr<SocketServer> SocketServer::CreateDefault() {
#if defined(__native_client__)
return std::unique_ptr<SocketServer>(new rtc::NullSocketServer);
#else
return std::unique_ptr<SocketServer>(new rtc::PhysicalSocketServer);
#endif
}
PhysicalSocket::PhysicalSocket(PhysicalSocketServer* ss, SOCKET s)
: ss_(ss),
s_(s),
error_(0),
state_((s == INVALID_SOCKET) ? CS_CLOSED : CS_CONNECTED),
resolver_(nullptr) {
if (s_ != INVALID_SOCKET) {
SetEnabledEvents(DE_READ | DE_WRITE);
int type = SOCK_STREAM;
socklen_t len = sizeof(type);
const int res =
getsockopt(s_, SOL_SOCKET, SO_TYPE, (SockOptArg)&type, &len);
RTC_DCHECK_EQ(0, res);
udp_ = (SOCK_DGRAM == type);
}
}
PhysicalSocket::~PhysicalSocket() {
Close();
}
bool PhysicalSocket::Create(int family, int type) {
Close();
s_ = ::socket(family, type, 0);
udp_ = (SOCK_DGRAM == type);
family_ = family;
UpdateLastError();
if (udp_) {
SetEnabledEvents(DE_READ | DE_WRITE);
}
return s_ != INVALID_SOCKET;
}
SocketAddress PhysicalSocket::GetLocalAddress() const {
sockaddr_storage addr_storage = {};
socklen_t addrlen = sizeof(addr_storage);
sockaddr* addr = reinterpret_cast<sockaddr*>(&addr_storage);
int result = ::getsockname(s_, addr, &addrlen);
SocketAddress address;
if (result >= 0) {
SocketAddressFromSockAddrStorage(addr_storage, &address);
} else {
RTC_LOG(LS_WARNING) << "GetLocalAddress: unable to get local addr, socket="
<< s_;
}
return address;
}
SocketAddress PhysicalSocket::GetRemoteAddress() const {
sockaddr_storage addr_storage = {};
socklen_t addrlen = sizeof(addr_storage);
sockaddr* addr = reinterpret_cast<sockaddr*>(&addr_storage);
int result = ::getpeername(s_, addr, &addrlen);
SocketAddress address;
if (result >= 0) {
SocketAddressFromSockAddrStorage(addr_storage, &address);
} else {
RTC_LOG(LS_WARNING)
<< "GetRemoteAddress: unable to get remote addr, socket=" << s_;
}
return address;
}
int PhysicalSocket::Bind(const SocketAddress& bind_addr) {
SocketAddress copied_bind_addr = bind_addr;
// If a network binder is available, use it to bind a socket to an interface
// instead of bind(), since this is more reliable on an OS with a weak host
// model.
if (ss_->network_binder() && !bind_addr.IsAnyIP()) {
NetworkBindingResult result =
ss_->network_binder()->BindSocketToNetwork(s_, bind_addr.ipaddr());
if (result == NetworkBindingResult::SUCCESS) {
// Since the network binder handled binding the socket to the desired
// network interface, we don't need to (and shouldn't) include an IP in
// the bind() call; bind() just needs to assign a port.
copied_bind_addr.SetIP(GetAnyIP(copied_bind_addr.ipaddr().family()));
} else if (result == NetworkBindingResult::NOT_IMPLEMENTED) {
RTC_LOG(LS_INFO) << "Can't bind socket to network because "
"network binding is not implemented for this OS.";
} else {
if (bind_addr.IsLoopbackIP()) {
// If we couldn't bind to a loopback IP (which should only happen in
// test scenarios), continue on. This may be expected behavior.
RTC_LOG(LS_VERBOSE) << "Binding socket to loopback address"
<< " failed; result: " << static_cast<int>(result);
} else {
RTC_LOG(LS_WARNING) << "Binding socket to network address"
<< " failed; result: " << static_cast<int>(result);
// If a network binding was attempted and failed, we should stop here
// and not try to use the socket. Otherwise, we may end up sending
// packets with an invalid source address.
// See: https://bugs.chromium.org/p/webrtc/issues/detail?id=7026
return -1;
}
}
}
sockaddr_storage addr_storage;
size_t len = copied_bind_addr.ToSockAddrStorage(&addr_storage);
sockaddr* addr = reinterpret_cast<sockaddr*>(&addr_storage);
int err = ::bind(s_, addr, static_cast<int>(len));
UpdateLastError();
#if !defined(NDEBUG)
if (0 == err) {
dbg_addr_ = "Bound @ ";
dbg_addr_.append(GetLocalAddress().ToString());
}
#endif
return err;
}
int PhysicalSocket::Connect(const SocketAddress& addr) {
// TODO(pthatcher): Implicit creation is required to reconnect...
// ...but should we make it more explicit?
if (state_ != CS_CLOSED) {
SetError(EALREADY);
return SOCKET_ERROR;
}
if (addr.IsUnresolvedIP()) {
RTC_LOG(LS_VERBOSE) << "Resolving addr in PhysicalSocket::Connect";
resolver_ = new AsyncResolver();
resolver_->SignalDone.connect(this, &PhysicalSocket::OnResolveResult);
resolver_->Start(addr);
state_ = CS_CONNECTING;
return 0;
}
return DoConnect(addr);
}
int PhysicalSocket::DoConnect(const SocketAddress& connect_addr) {
if ((s_ == INVALID_SOCKET) && !Create(connect_addr.family(), SOCK_STREAM)) {
return SOCKET_ERROR;
}
sockaddr_storage addr_storage;
size_t len = connect_addr.ToSockAddrStorage(&addr_storage);
sockaddr* addr = reinterpret_cast<sockaddr*>(&addr_storage);
int err = ::connect(s_, addr, static_cast<int>(len));
UpdateLastError();
uint8_t events = DE_READ | DE_WRITE;
if (err == 0) {
state_ = CS_CONNECTED;
} else if (IsBlockingError(GetError())) {
state_ = CS_CONNECTING;
events |= DE_CONNECT;
} else {
return SOCKET_ERROR;
}
EnableEvents(events);
return 0;
}
int PhysicalSocket::GetError() const {
CritScope cs(&crit_);
return error_;
}
void PhysicalSocket::SetError(int error) {
CritScope cs(&crit_);
error_ = error;
}
AsyncSocket::ConnState PhysicalSocket::GetState() const {
return state_;
}
int PhysicalSocket::GetOption(Option opt, int* value) {
int slevel;
int sopt;
if (TranslateOption(opt, &slevel, &sopt) == -1)
return -1;
socklen_t optlen = sizeof(*value);
int ret = ::getsockopt(s_, slevel, sopt, (SockOptArg)value, &optlen);
if (ret == -1) {
return -1;
}
if (opt == OPT_DONTFRAGMENT) {
#if defined(WEBRTC_LINUX) && !defined(WEBRTC_ANDROID)
*value = (*value != IP_PMTUDISC_DONT) ? 1 : 0;
#endif
} else if (opt == OPT_DSCP) {
#if defined(WEBRTC_POSIX)
// unshift DSCP value to get six most significant bits of IP DiffServ field
*value >>= 2;
#endif
}
return ret;
}
int PhysicalSocket::SetOption(Option opt, int value) {
int slevel;
int sopt;
if (TranslateOption(opt, &slevel, &sopt) == -1)
return -1;
if (opt == OPT_DONTFRAGMENT) {
#if defined(WEBRTC_LINUX) && !defined(WEBRTC_ANDROID)
value = (value) ? IP_PMTUDISC_DO : IP_PMTUDISC_DONT;
#endif
} else if (opt == OPT_DSCP) {
#if defined(WEBRTC_POSIX)
// shift DSCP value to fit six most significant bits of IP DiffServ field
value <<= 2;
#endif
}
#if defined(WEBRTC_POSIX)
if (sopt == IPV6_TCLASS) {
// Set the IPv4 option in all cases to support dual-stack sockets.
::setsockopt(s_, IPPROTO_IP, IP_TOS, (SockOptArg)&value, sizeof(value));
}
#endif
return ::setsockopt(s_, slevel, sopt, (SockOptArg)&value, sizeof(value));
}
int PhysicalSocket::Send(const void* pv, size_t cb) {
int sent = DoSend(
s_, reinterpret_cast<const char*>(pv), static_cast<int>(cb),
#if defined(WEBRTC_LINUX) && !defined(WEBRTC_ANDROID)
// Suppress SIGPIPE. Without this, attempting to send on a socket whose
// other end is closed will result in a SIGPIPE signal being raised to
// our process, which by default will terminate the process, which we
// don't want. By specifying this flag, we'll just get the error EPIPE
// instead and can handle the error gracefully.
MSG_NOSIGNAL
#else
0
#endif
);
UpdateLastError();
MaybeRemapSendError();
// We have seen minidumps where this may be false.
RTC_DCHECK(sent <= static_cast<int>(cb));
if ((sent > 0 && sent < static_cast<int>(cb)) ||
(sent < 0 && IsBlockingError(GetError()))) {
EnableEvents(DE_WRITE);
}
return sent;
}
int PhysicalSocket::SendTo(const void* buffer,
size_t length,
const SocketAddress& addr) {
sockaddr_storage saddr;
size_t len = addr.ToSockAddrStorage(&saddr);
int sent =
DoSendTo(s_, static_cast<const char*>(buffer), static_cast<int>(length),
#if defined(WEBRTC_LINUX) && !defined(WEBRTC_ANDROID)
// Suppress SIGPIPE. See above for explanation.
MSG_NOSIGNAL,
#else
0,
#endif
reinterpret_cast<sockaddr*>(&saddr), static_cast<int>(len));
UpdateLastError();
MaybeRemapSendError();
// We have seen minidumps where this may be false.
RTC_DCHECK(sent <= static_cast<int>(length));
if ((sent > 0 && sent < static_cast<int>(length)) ||
(sent < 0 && IsBlockingError(GetError()))) {
EnableEvents(DE_WRITE);
}
return sent;
}
int PhysicalSocket::Recv(void* buffer, size_t length, int64_t* timestamp) {
int received =
::recv(s_, static_cast<char*>(buffer), static_cast<int>(length), 0);
if ((received == 0) && (length != 0)) {
// Note: on graceful shutdown, recv can return 0. In this case, we
// pretend it is blocking, and then signal close, so that simplifying
// assumptions can be made about Recv.
RTC_LOG(LS_WARNING) << "EOF from socket; deferring close event";
// Must turn this back on so that the select() loop will notice the close
// event.
EnableEvents(DE_READ);
SetError(EWOULDBLOCK);
return SOCKET_ERROR;
}
if (timestamp) {
*timestamp = GetSocketRecvTimestamp(s_);
}
UpdateLastError();
int error = GetError();
bool success = (received >= 0) || IsBlockingError(error);
if (udp_ || success) {
EnableEvents(DE_READ);
}
if (!success) {
RTC_LOG_F(LS_VERBOSE) << "Error = " << error;
}
return received;
}
int PhysicalSocket::RecvFrom(void* buffer,
size_t length,
SocketAddress* out_addr,
int64_t* timestamp) {
sockaddr_storage addr_storage;
socklen_t addr_len = sizeof(addr_storage);
sockaddr* addr = reinterpret_cast<sockaddr*>(&addr_storage);
int received = ::recvfrom(s_, static_cast<char*>(buffer),
static_cast<int>(length), 0, addr, &addr_len);
if (timestamp) {
*timestamp = GetSocketRecvTimestamp(s_);
}
UpdateLastError();
if ((received >= 0) && (out_addr != nullptr))
SocketAddressFromSockAddrStorage(addr_storage, out_addr);
int error = GetError();
bool success = (received >= 0) || IsBlockingError(error);
if (udp_ || success) {
EnableEvents(DE_READ);
}
if (!success) {
RTC_LOG_F(LS_VERBOSE) << "Error = " << error;
}
return received;
}
int PhysicalSocket::Listen(int backlog) {
int err = ::listen(s_, backlog);
UpdateLastError();
if (err == 0) {
state_ = CS_CONNECTING;
EnableEvents(DE_ACCEPT);
#if !defined(NDEBUG)
dbg_addr_ = "Listening @ ";
dbg_addr_.append(GetLocalAddress().ToString());
#endif
}
return err;
}
AsyncSocket* PhysicalSocket::Accept(SocketAddress* out_addr) {
// Always re-subscribe DE_ACCEPT to make sure new incoming connections will
// trigger an event even if DoAccept returns an error here.
EnableEvents(DE_ACCEPT);
sockaddr_storage addr_storage;
socklen_t addr_len = sizeof(addr_storage);
sockaddr* addr = reinterpret_cast<sockaddr*>(&addr_storage);
SOCKET s = DoAccept(s_, addr, &addr_len);
UpdateLastError();
if (s == INVALID_SOCKET)
return nullptr;
if (out_addr != nullptr)
SocketAddressFromSockAddrStorage(addr_storage, out_addr);
return ss_->WrapSocket(s);
}
int PhysicalSocket::Close() {
if (s_ == INVALID_SOCKET)
return 0;
int err = ::closesocket(s_);
UpdateLastError();
s_ = INVALID_SOCKET;
state_ = CS_CLOSED;
SetEnabledEvents(0);
if (resolver_) {
resolver_->Destroy(false);
resolver_ = nullptr;
}
return err;
}
SOCKET PhysicalSocket::DoAccept(SOCKET socket,
sockaddr* addr,
socklen_t* addrlen) {
return ::accept(socket, addr, addrlen);
}
int PhysicalSocket::DoSend(SOCKET socket, const char* buf, int len, int flags) {
return ::send(socket, buf, len, flags);
}
int PhysicalSocket::DoSendTo(SOCKET socket,
const char* buf,
int len,
int flags,
const struct sockaddr* dest_addr,
socklen_t addrlen) {
return ::sendto(socket, buf, len, flags, dest_addr, addrlen);
}
void PhysicalSocket::OnResolveResult(AsyncResolverInterface* resolver) {
if (resolver != resolver_) {
return;
}
int error = resolver_->GetError();
if (error == 0) {
error = DoConnect(resolver_->address());
} else {
Close();
}
if (error) {
SetError(error);
SignalCloseEvent(this, error);
}
}
void PhysicalSocket::UpdateLastError() {
SetError(LAST_SYSTEM_ERROR);
}
void PhysicalSocket::MaybeRemapSendError() {
#if defined(WEBRTC_MAC)
// https://developer.apple.com/library/mac/documentation/Darwin/
// Reference/ManPages/man2/sendto.2.html
// ENOBUFS - The output queue for a network interface is full.
// This generally indicates that the interface has stopped sending,
// but may be caused by transient congestion.
if (GetError() == ENOBUFS) {
SetError(EWOULDBLOCK);
}
#endif
}
void PhysicalSocket::SetEnabledEvents(uint8_t events) {
enabled_events_ = events;
}
void PhysicalSocket::EnableEvents(uint8_t events) {
enabled_events_ |= events;
}
void PhysicalSocket::DisableEvents(uint8_t events) {
enabled_events_ &= ~events;
}
int PhysicalSocket::TranslateOption(Option opt, int* slevel, int* sopt) {
switch (opt) {
case OPT_DONTFRAGMENT:
#if defined(WEBRTC_WIN)
*slevel = IPPROTO_IP;
*sopt = IP_DONTFRAGMENT;
break;
#elif defined(WEBRTC_MAC) || defined(BSD) || defined(__native_client__)
RTC_LOG(LS_WARNING) << "Socket::OPT_DONTFRAGMENT not supported.";
return -1;
#elif defined(WEBRTC_POSIX)
*slevel = IPPROTO_IP;
*sopt = IP_MTU_DISCOVER;
break;
#endif
case OPT_RCVBUF:
*slevel = SOL_SOCKET;
*sopt = SO_RCVBUF;
break;
case OPT_SNDBUF:
*slevel = SOL_SOCKET;
*sopt = SO_SNDBUF;
break;
case OPT_NODELAY:
*slevel = IPPROTO_TCP;
*sopt = TCP_NODELAY;
break;
case OPT_DSCP:
#if defined(WEBRTC_POSIX)
if (family_ == AF_INET6) {
*slevel = IPPROTO_IPV6;
*sopt = IPV6_TCLASS;
} else {
*slevel = IPPROTO_IP;
*sopt = IP_TOS;
}
break;
#else
RTC_LOG(LS_WARNING) << "Socket::OPT_DSCP not supported.";
return -1;
#endif
case OPT_RTP_SENDTIME_EXTN_ID:
return -1; // No logging is necessary as this not a OS socket option.
default:
RTC_NOTREACHED();
return -1;
}
return 0;
}
SocketDispatcher::SocketDispatcher(PhysicalSocketServer* ss)
#if defined(WEBRTC_WIN)
: PhysicalSocket(ss),
id_(0),
signal_close_(false)
#else
: PhysicalSocket(ss)
#endif
{
}
SocketDispatcher::SocketDispatcher(SOCKET s, PhysicalSocketServer* ss)
#if defined(WEBRTC_WIN)
: PhysicalSocket(ss, s),
id_(0),
signal_close_(false)
#else
: PhysicalSocket(ss, s)
#endif
{
}
SocketDispatcher::~SocketDispatcher() {
Close();
}
bool SocketDispatcher::Initialize() {
RTC_DCHECK(s_ != INVALID_SOCKET);
// Must be a non-blocking
#if defined(WEBRTC_WIN)
u_long argp = 1;
ioctlsocket(s_, FIONBIO, &argp);
#elif defined(WEBRTC_POSIX)
fcntl(s_, F_SETFL, fcntl(s_, F_GETFL, 0) | O_NONBLOCK);
#endif
#if defined(WEBRTC_IOS)
// iOS may kill sockets when the app is moved to the background
// (specifically, if the app doesn't use the "voip" UIBackgroundMode). When
// we attempt to write to such a socket, SIGPIPE will be raised, which by
// default will terminate the process, which we don't want. By specifying
// this socket option, SIGPIPE will be disabled for the socket.
int value = 1;
::setsockopt(s_, SOL_SOCKET, SO_NOSIGPIPE, &value, sizeof(value));
#endif
ss_->Add(this);
return true;
}
bool SocketDispatcher::Create(int type) {
return Create(AF_INET, type);
}
bool SocketDispatcher::Create(int family, int type) {
// Change the socket to be non-blocking.
if (!PhysicalSocket::Create(family, type))
return false;
if (!Initialize())
return false;
#if defined(WEBRTC_WIN)
do {
id_ = ++next_id_;
} while (id_ == 0);
#endif
return true;
}
#if defined(WEBRTC_WIN)
WSAEVENT SocketDispatcher::GetWSAEvent() {
return WSA_INVALID_EVENT;
}
SOCKET SocketDispatcher::GetSocket() {
return s_;
}
bool SocketDispatcher::CheckSignalClose() {
if (!signal_close_)
return false;
char ch;
if (recv(s_, &ch, 1, MSG_PEEK) > 0)
return false;
state_ = CS_CLOSED;
signal_close_ = false;
SignalCloseEvent(this, signal_err_);
return true;
}
int SocketDispatcher::next_id_ = 0;
#elif defined(WEBRTC_POSIX)
int SocketDispatcher::GetDescriptor() {
return s_;
}
bool SocketDispatcher::IsDescriptorClosed() {
if (udp_) {
// The MSG_PEEK trick doesn't work for UDP, since (at least in some
// circumstances) it requires reading an entire UDP packet, which would be
// bad for performance here. So, just check whether |s_| has been closed,
// which should be sufficient.
return s_ == INVALID_SOCKET;
}
// We don't have a reliable way of distinguishing end-of-stream
// from readability. So test on each readable call. Is this
// inefficient? Probably.
char ch;
ssize_t res = ::recv(s_, &ch, 1, MSG_PEEK);
if (res > 0) {
// Data available, so not closed.
return false;
} else if (res == 0) {
// EOF, so closed.
return true;
} else { // error
switch (errno) {
// Returned if we've already closed s_.
case EBADF:
// Returned during ungraceful peer shutdown.
case ECONNRESET:
return true;
// The normal blocking error; don't log anything.
case EWOULDBLOCK:
// Interrupted system call.
case EINTR:
return false;
default:
// Assume that all other errors are just blocking errors, meaning the
// connection is still good but we just can't read from it right now.
// This should only happen when connecting (and at most once), because
// in all other cases this function is only called if the file
// descriptor is already known to be in the readable state. However,
// it's not necessary a problem if we spuriously interpret a
// "connection lost"-type error as a blocking error, because typically
// the next recv() will get EOF, so we'll still eventually notice that
// the socket is closed.
RTC_LOG_ERR(LS_WARNING) << "Assuming benign blocking error";
return false;
}
}
}
#endif // WEBRTC_POSIX
uint32_t SocketDispatcher::GetRequestedEvents() {
return enabled_events();
}
void SocketDispatcher::OnPreEvent(uint32_t ff) {
if ((ff & DE_CONNECT) != 0)
state_ = CS_CONNECTED;
#if defined(WEBRTC_WIN)
// We set CS_CLOSED from CheckSignalClose.
#elif defined(WEBRTC_POSIX)
if ((ff & DE_CLOSE) != 0)
state_ = CS_CLOSED;
#endif
}
#if defined(WEBRTC_WIN)
void SocketDispatcher::OnEvent(uint32_t ff, int err) {
int cache_id = id_;
// Make sure we deliver connect/accept first. Otherwise, consumers may see
// something like a READ followed by a CONNECT, which would be odd.
if (((ff & DE_CONNECT) != 0) && (id_ == cache_id)) {
if (ff != DE_CONNECT)
RTC_LOG(LS_VERBOSE) << "Signalled with DE_CONNECT: " << ff;
DisableEvents(DE_CONNECT);
#if !defined(NDEBUG)
dbg_addr_ = "Connected @ ";
dbg_addr_.append(GetRemoteAddress().ToString());
#endif
SignalConnectEvent(this);
}
if (((ff & DE_ACCEPT) != 0) && (id_ == cache_id)) {
DisableEvents(DE_ACCEPT);
SignalReadEvent(this);
}
if ((ff & DE_READ) != 0) {
DisableEvents(DE_READ);
SignalReadEvent(this);
}
if (((ff & DE_WRITE) != 0) && (id_ == cache_id)) {
DisableEvents(DE_WRITE);
SignalWriteEvent(this);
}
if (((ff & DE_CLOSE) != 0) && (id_ == cache_id)) {
signal_close_ = true;
signal_err_ = err;
}
}
#elif defined(WEBRTC_POSIX)
void SocketDispatcher::OnEvent(uint32_t ff, int err) {
#if defined(WEBRTC_USE_EPOLL)
// Remember currently enabled events so we can combine multiple changes
// into one update call later.
// The signal handlers might re-enable events disabled here, so we can't
// keep a list of events to disable at the end of the method. This list
// would not be updated with the events enabled by the signal handlers.
StartBatchedEventUpdates();
#endif
// Make sure we deliver connect/accept first. Otherwise, consumers may see
// something like a READ followed by a CONNECT, which would be odd.
if ((ff & DE_CONNECT) != 0) {
DisableEvents(DE_CONNECT);
SignalConnectEvent(this);
}
if ((ff & DE_ACCEPT) != 0) {
DisableEvents(DE_ACCEPT);
SignalReadEvent(this);
}
if ((ff & DE_READ) != 0) {
DisableEvents(DE_READ);
SignalReadEvent(this);
}
if ((ff & DE_WRITE) != 0) {
DisableEvents(DE_WRITE);
SignalWriteEvent(this);
}
if ((ff & DE_CLOSE) != 0) {
// The socket is now dead to us, so stop checking it.
SetEnabledEvents(0);
SignalCloseEvent(this, err);
}
#if defined(WEBRTC_USE_EPOLL)
FinishBatchedEventUpdates();
#endif
}
#endif // WEBRTC_POSIX
#if defined(WEBRTC_USE_EPOLL)
inline static int GetEpollEvents(uint32_t ff) {
int events = 0;
if (ff & (DE_READ | DE_ACCEPT)) {
events |= EPOLLIN;
}
if (ff & (DE_WRITE | DE_CONNECT)) {
events |= EPOLLOUT;
}
return events;
}
void SocketDispatcher::StartBatchedEventUpdates() {
RTC_DCHECK_EQ(saved_enabled_events_, -1);
saved_enabled_events_ = enabled_events();
}
void SocketDispatcher::FinishBatchedEventUpdates() {
RTC_DCHECK_NE(saved_enabled_events_, -1);
uint8_t old_events = static_cast<uint8_t>(saved_enabled_events_);
saved_enabled_events_ = -1;
MaybeUpdateDispatcher(old_events);
}
void SocketDispatcher::MaybeUpdateDispatcher(uint8_t old_events) {
if (GetEpollEvents(enabled_events()) != GetEpollEvents(old_events) &&
saved_enabled_events_ == -1) {
ss_->Update(this);
}
}
void SocketDispatcher::SetEnabledEvents(uint8_t events) {
uint8_t old_events = enabled_events();
PhysicalSocket::SetEnabledEvents(events);
MaybeUpdateDispatcher(old_events);
}
void SocketDispatcher::EnableEvents(uint8_t events) {
uint8_t old_events = enabled_events();
PhysicalSocket::EnableEvents(events);
MaybeUpdateDispatcher(old_events);
}
void SocketDispatcher::DisableEvents(uint8_t events) {
uint8_t old_events = enabled_events();
PhysicalSocket::DisableEvents(events);
MaybeUpdateDispatcher(old_events);
}
#endif // WEBRTC_USE_EPOLL
int SocketDispatcher::Close() {
if (s_ == INVALID_SOCKET)
return 0;
#if defined(WEBRTC_WIN)
id_ = 0;
signal_close_ = false;
#endif
#if defined(WEBRTC_USE_EPOLL)
// If we're batching events, the socket can be closed and reopened
// during the batch. Set saved_enabled_events_ to 0 here so the new
// socket, if any, has the correct old events bitfield
if (saved_enabled_events_ != -1) {
saved_enabled_events_ = 0;
}
#endif
ss_->Remove(this);
return PhysicalSocket::Close();
}
#if defined(WEBRTC_POSIX)
class EventDispatcher : public Dispatcher {
public:
EventDispatcher(PhysicalSocketServer* ss) : ss_(ss), fSignaled_(false) {
if (pipe(afd_) < 0)
RTC_LOG(LERROR) << "pipe failed";
ss_->Add(this);
}
~EventDispatcher() override {
ss_->Remove(this);
close(afd_[0]);
close(afd_[1]);
}
virtual void Signal() {
CritScope cs(&crit_);
if (!fSignaled_) {
const uint8_t b[1] = {0};
const ssize_t res = write(afd_[1], b, sizeof(b));
RTC_DCHECK_EQ(1, res);
fSignaled_ = true;
}
}
uint32_t GetRequestedEvents() override { return DE_READ; }
void OnPreEvent(uint32_t ff) override {
// It is not possible to perfectly emulate an auto-resetting event with
// pipes. This simulates it by resetting before the event is handled.
CritScope cs(&crit_);
if (fSignaled_) {
uint8_t b[4]; // Allow for reading more than 1 byte, but expect 1.
const ssize_t res = read(afd_[0], b, sizeof(b));
RTC_DCHECK_EQ(1, res);
fSignaled_ = false;
}
}
void OnEvent(uint32_t ff, int err) override { RTC_NOTREACHED(); }
int GetDescriptor() override { return afd_[0]; }
bool IsDescriptorClosed() override { return false; }
private:
PhysicalSocketServer* ss_;
int afd_[2];
bool fSignaled_;
RecursiveCriticalSection crit_;
};
#endif // WEBRTC_POSIX
#if defined(WEBRTC_WIN)
static uint32_t FlagsToEvents(uint32_t events) {
uint32_t ffFD = FD_CLOSE;
if (events & DE_READ)
ffFD |= FD_READ;
if (events & DE_WRITE)
ffFD |= FD_WRITE;
if (events & DE_CONNECT)
ffFD |= FD_CONNECT;
if (events & DE_ACCEPT)
ffFD |= FD_ACCEPT;
return ffFD;
}
class EventDispatcher : public Dispatcher {
public:
EventDispatcher(PhysicalSocketServer* ss) : ss_(ss) {
hev_ = WSACreateEvent();
if (hev_) {
ss_->Add(this);
}
}
~EventDispatcher() override {
if (hev_ != nullptr) {
ss_->Remove(this);
WSACloseEvent(hev_);
hev_ = nullptr;
}
}
virtual void Signal() {
if (hev_ != nullptr)
WSASetEvent(hev_);
}
uint32_t GetRequestedEvents() override { return 0; }
void OnPreEvent(uint32_t ff) override { WSAResetEvent(hev_); }
void OnEvent(uint32_t ff, int err) override {}
WSAEVENT GetWSAEvent() override { return hev_; }
SOCKET GetSocket() override { return INVALID_SOCKET; }
bool CheckSignalClose() override { return false; }
private:
PhysicalSocketServer* ss_;
WSAEVENT hev_;
};
#endif // WEBRTC_WIN
// Sets the value of a boolean value to false when signaled.
class Signaler : public EventDispatcher {
public:
Signaler(PhysicalSocketServer* ss, bool* pf) : EventDispatcher(ss), pf_(pf) {}
~Signaler() override {}
void OnEvent(uint32_t ff, int err) override {
if (pf_)
*pf_ = false;
}
private:
bool* pf_;
};
PhysicalSocketServer::PhysicalSocketServer()
:
#if defined(WEBRTC_USE_EPOLL)
// Since Linux 2.6.8, the size argument is ignored, but must be greater
// than zero. Before that the size served as hint to the kernel for the
// amount of space to initially allocate in internal data structures.
epoll_fd_(epoll_create(FD_SETSIZE)),
#endif
#if defined(WEBRTC_WIN)
socket_ev_(WSACreateEvent()),
#endif
fWait_(false) {
#if defined(WEBRTC_USE_EPOLL)
if (epoll_fd_ == -1) {
// Not an error, will fall back to "select" below.
RTC_LOG_E(LS_WARNING, EN, errno) << "epoll_create";
// Note that -1 == INVALID_SOCKET, the alias used by later checks.
}
#endif
signal_wakeup_ = new Signaler(this, &fWait_);
}
PhysicalSocketServer::~PhysicalSocketServer() {
#if defined(WEBRTC_WIN)
WSACloseEvent(socket_ev_);
#endif
delete signal_wakeup_;
#if defined(WEBRTC_USE_EPOLL)
if (epoll_fd_ != INVALID_SOCKET) {
close(epoll_fd_);
}
#endif
RTC_DCHECK(dispatcher_by_key_.empty());
RTC_DCHECK(key_by_dispatcher_.empty());
}
void PhysicalSocketServer::WakeUp() {
signal_wakeup_->Signal();
}
Socket* PhysicalSocketServer::CreateSocket(int family, int type) {
PhysicalSocket* socket = new PhysicalSocket(this);
if (socket->Create(family, type)) {
return socket;
} else {
delete socket;
return nullptr;
}
}
AsyncSocket* PhysicalSocketServer::CreateAsyncSocket(int family, int type) {
SocketDispatcher* dispatcher = new SocketDispatcher(this);
if (dispatcher->Create(family, type)) {
return dispatcher;
} else {
delete dispatcher;
return nullptr;
}
}
AsyncSocket* PhysicalSocketServer::WrapSocket(SOCKET s) {
SocketDispatcher* dispatcher = new SocketDispatcher(s, this);
if (dispatcher->Initialize()) {
return dispatcher;
} else {
delete dispatcher;
return nullptr;
}
}
void PhysicalSocketServer::Add(Dispatcher* pdispatcher) {
CritScope cs(&crit_);
if (key_by_dispatcher_.count(pdispatcher)) {
RTC_LOG(LS_WARNING)
<< "PhysicalSocketServer asked to add a duplicate dispatcher.";
return;
}
uint64_t key = next_dispatcher_key_++;
dispatcher_by_key_.emplace(key, pdispatcher);
key_by_dispatcher_.emplace(pdispatcher, key);
#if defined(WEBRTC_USE_EPOLL)
if (epoll_fd_ != INVALID_SOCKET) {
AddEpoll(pdispatcher, key);
}
#endif // WEBRTC_USE_EPOLL
}
void PhysicalSocketServer::Remove(Dispatcher* pdispatcher) {
CritScope cs(&crit_);
if (!key_by_dispatcher_.count(pdispatcher)) {
RTC_LOG(LS_WARNING)
<< "PhysicalSocketServer asked to remove a unknown "
"dispatcher, potentially from a duplicate call to Add.";
return;
}
uint64_t key = key_by_dispatcher_.at(pdispatcher);
key_by_dispatcher_.erase(pdispatcher);
dispatcher_by_key_.erase(key);
#if defined(WEBRTC_USE_EPOLL)
if (epoll_fd_ != INVALID_SOCKET) {
RemoveEpoll(pdispatcher);
}
#endif // WEBRTC_USE_EPOLL
}
void PhysicalSocketServer::Update(Dispatcher* pdispatcher) {
#if defined(WEBRTC_USE_EPOLL)
if (epoll_fd_ == INVALID_SOCKET) {
return;
}
// Don't update dispatchers that haven't yet been added.
CritScope cs(&crit_);
if (!key_by_dispatcher_.count(pdispatcher)) {
return;
}
UpdateEpoll(pdispatcher, key_by_dispatcher_.at(pdispatcher));
#endif
}
#if defined(WEBRTC_POSIX)
bool PhysicalSocketServer::Wait(int cmsWait, bool process_io) {
// We don't support reentrant waiting.
RTC_DCHECK(!waiting_);
ScopedSetTrue s(&waiting_);
#if defined(WEBRTC_USE_EPOLL)
// We don't keep a dedicated "epoll" descriptor containing only the non-IO
// (i.e. signaling) dispatcher, so "poll" will be used instead of the default
// "select" to support sockets larger than FD_SETSIZE.
if (!process_io) {
return WaitPoll(cmsWait, signal_wakeup_);
} else if (epoll_fd_ != INVALID_SOCKET) {
return WaitEpoll(cmsWait);
}
#endif
return WaitSelect(cmsWait, process_io);
}
static void ProcessEvents(Dispatcher* dispatcher,
bool readable,
bool writable,
bool check_error) {
int errcode = 0;
// TODO(pthatcher): Should we set errcode if getsockopt fails?
if (check_error) {
socklen_t len = sizeof(errcode);
::getsockopt(dispatcher->GetDescriptor(), SOL_SOCKET, SO_ERROR, &errcode,
&len);
}
// Most often the socket is writable or readable or both, so make a single
// virtual call to get requested events
const uint32_t requested_events = dispatcher->GetRequestedEvents();
uint32_t ff = 0;
// Check readable descriptors. If we're waiting on an accept, signal
// that. Otherwise we're waiting for data, check to see if we're
// readable or really closed.
// TODO(pthatcher): Only peek at TCP descriptors.
if (readable) {
if (requested_events & DE_ACCEPT) {
ff |= DE_ACCEPT;
} else if (errcode || dispatcher->IsDescriptorClosed()) {
ff |= DE_CLOSE;
} else {
ff |= DE_READ;
}
}
// Check writable descriptors. If we're waiting on a connect, detect
// success versus failure by the reaped error code.
if (writable) {
if (requested_events & DE_CONNECT) {
if (!errcode) {
ff |= DE_CONNECT;
} else {
ff |= DE_CLOSE;
}
} else {
ff |= DE_WRITE;
}
}
// Tell the descriptor about the event.
if (ff != 0) {
dispatcher->OnPreEvent(ff);
dispatcher->OnEvent(ff, errcode);
}
}
bool PhysicalSocketServer::WaitSelect(int cmsWait, bool process_io) {
// Calculate timing information
struct timeval* ptvWait = nullptr;
struct timeval tvWait;
int64_t stop_us;
if (cmsWait != kForever) {
// Calculate wait timeval
tvWait.tv_sec = cmsWait / 1000;
tvWait.tv_usec = (cmsWait % 1000) * 1000;
ptvWait = &tvWait;
// Calculate when to return
stop_us = rtc::TimeMicros() + cmsWait * 1000;
}
fd_set fdsRead;
fd_set fdsWrite;
// Explicitly unpoison these FDs on MemorySanitizer which doesn't handle the
// inline assembly in FD_ZERO.
// http://crbug.com/344505
#ifdef MEMORY_SANITIZER
__msan_unpoison(&fdsRead, sizeof(fdsRead));
__msan_unpoison(&fdsWrite, sizeof(fdsWrite));
#endif
fWait_ = true;
while (fWait_) {
// Zero all fd_sets. Although select() zeros the descriptors not signaled,
// we may need to do this for dispatchers that were deleted while
// iterating.
FD_ZERO(&fdsRead);
FD_ZERO(&fdsWrite);
int fdmax = -1;
{
CritScope cr(&crit_);
current_dispatcher_keys_.clear();
for (auto const& kv : dispatcher_by_key_) {
uint64_t key = kv.first;
Dispatcher* pdispatcher = kv.second;
// Query dispatchers for read and write wait state
if (!process_io && (pdispatcher != signal_wakeup_))
continue;
current_dispatcher_keys_.push_back(key);
int fd = pdispatcher->GetDescriptor();
// "select"ing a file descriptor that is equal to or larger than
// FD_SETSIZE will result in undefined behavior.
RTC_DCHECK_LT(fd, FD_SETSIZE);
if (fd > fdmax)
fdmax = fd;
uint32_t ff = pdispatcher->GetRequestedEvents();
if (ff & (DE_READ | DE_ACCEPT))
FD_SET(fd, &fdsRead);
if (ff & (DE_WRITE | DE_CONNECT))
FD_SET(fd, &fdsWrite);
}
}
// Wait then call handlers as appropriate
// < 0 means error
// 0 means timeout
// > 0 means count of descriptors ready
int n = select(fdmax + 1, &fdsRead, &fdsWrite, nullptr, ptvWait);
// If error, return error.
if (n < 0) {
if (errno != EINTR) {
RTC_LOG_E(LS_ERROR, EN, errno) << "select";
return false;
}
// Else ignore the error and keep going. If this EINTR was for one of the
// signals managed by this PhysicalSocketServer, the
// PosixSignalDeliveryDispatcher will be in the signaled state in the next
// iteration.
} else if (n == 0) {
// If timeout, return success
return true;
} else {
// We have signaled descriptors
CritScope cr(&crit_);
// Iterate only on the dispatchers whose sockets were passed into
// WSAEventSelect; this avoids the ABA problem (a socket being
// destroyed and a new one created with the same file descriptor).
for (uint64_t key : current_dispatcher_keys_) {
if (!dispatcher_by_key_.count(key))
continue;
Dispatcher* pdispatcher = dispatcher_by_key_.at(key);
int fd = pdispatcher->GetDescriptor();
bool readable = FD_ISSET(fd, &fdsRead);
if (readable) {
FD_CLR(fd, &fdsRead);
}
bool writable = FD_ISSET(fd, &fdsWrite);
if (writable) {
FD_CLR(fd, &fdsWrite);
}
// The error code can be signaled through reads or writes.
ProcessEvents(pdispatcher, readable, writable, readable || writable);
}
}
// Recalc the time remaining to wait. Doing it here means it doesn't get
// calced twice the first time through the loop
if (ptvWait) {
ptvWait->tv_sec = 0;
ptvWait->tv_usec = 0;
int64_t time_left_us = stop_us - rtc::TimeMicros();
if (time_left_us > 0) {
ptvWait->tv_sec = time_left_us / rtc::kNumMicrosecsPerSec;
ptvWait->tv_usec = time_left_us % rtc::kNumMicrosecsPerSec;
}
}
}
return true;
}
#if defined(WEBRTC_USE_EPOLL)
void PhysicalSocketServer::AddEpoll(Dispatcher* pdispatcher, uint64_t key) {
RTC_DCHECK(epoll_fd_ != INVALID_SOCKET);
int fd = pdispatcher->GetDescriptor();
RTC_DCHECK(fd != INVALID_SOCKET);
if (fd == INVALID_SOCKET) {
return;
}
struct epoll_event event = {0};
event.events = GetEpollEvents(pdispatcher->GetRequestedEvents());
event.data.u64 = key;
int err = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &event);
RTC_DCHECK_EQ(err, 0);
if (err == -1) {
RTC_LOG_E(LS_ERROR, EN, errno) << "epoll_ctl EPOLL_CTL_ADD";
}
}
void PhysicalSocketServer::RemoveEpoll(Dispatcher* pdispatcher) {
RTC_DCHECK(epoll_fd_ != INVALID_SOCKET);
int fd = pdispatcher->GetDescriptor();
RTC_DCHECK(fd != INVALID_SOCKET);
if (fd == INVALID_SOCKET) {
return;
}
struct epoll_event event = {0};
int err = epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, &event);
RTC_DCHECK(err == 0 || errno == ENOENT);
if (err == -1) {
if (errno == ENOENT) {
// Socket has already been closed.
RTC_LOG_E(LS_VERBOSE, EN, errno) << "epoll_ctl EPOLL_CTL_DEL";
} else {
RTC_LOG_E(LS_ERROR, EN, errno) << "epoll_ctl EPOLL_CTL_DEL";
}
}
}
void PhysicalSocketServer::UpdateEpoll(Dispatcher* pdispatcher, uint64_t key) {
RTC_DCHECK(epoll_fd_ != INVALID_SOCKET);
int fd = pdispatcher->GetDescriptor();
RTC_DCHECK(fd != INVALID_SOCKET);
if (fd == INVALID_SOCKET) {
return;
}
struct epoll_event event = {0};
event.events = GetEpollEvents(pdispatcher->GetRequestedEvents());
event.data.u64 = key;
int err = epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, fd, &event);
RTC_DCHECK_EQ(err, 0);
if (err == -1) {
RTC_LOG_E(LS_ERROR, EN, errno) << "epoll_ctl EPOLL_CTL_MOD";
}
}
bool PhysicalSocketServer::WaitEpoll(int cmsWait) {
RTC_DCHECK(epoll_fd_ != INVALID_SOCKET);
int64_t tvWait = -1;
int64_t tvStop = -1;
if (cmsWait != kForever) {
tvWait = cmsWait;
tvStop = TimeAfter(cmsWait);
}
fWait_ = true;
while (fWait_) {
// Wait then call handlers as appropriate
// < 0 means error
// 0 means timeout
// > 0 means count of descriptors ready
int n = epoll_wait(epoll_fd_, epoll_events_.data(), epoll_events_.size(),
static_cast<int>(tvWait));
if (n < 0) {
if (errno != EINTR) {
RTC_LOG_E(LS_ERROR, EN, errno) << "epoll";
return false;
}
// Else ignore the error and keep going. If this EINTR was for one of the
// signals managed by this PhysicalSocketServer, the
// PosixSignalDeliveryDispatcher will be in the signaled state in the next
// iteration.
} else if (n == 0) {
// If timeout, return success
return true;
} else {
// We have signaled descriptors
CritScope cr(&crit_);
for (int i = 0; i < n; ++i) {
const epoll_event& event = epoll_events_[i];
uint64_t key = event.data.u64;
if (!dispatcher_by_key_.count(key)) {
// The dispatcher for this socket no longer exists.
continue;
}
Dispatcher* pdispatcher = dispatcher_by_key_.at(key);
bool readable = (event.events & (EPOLLIN | EPOLLPRI));
bool writable = (event.events & EPOLLOUT);
bool check_error = (event.events & (EPOLLRDHUP | EPOLLERR | EPOLLHUP));
ProcessEvents(pdispatcher, readable, writable, check_error);
}
}
if (cmsWait != kForever) {
tvWait = TimeDiff(tvStop, TimeMillis());
if (tvWait <= 0) {
// Return success on timeout.
return true;
}
}
}
return true;
}
bool PhysicalSocketServer::WaitPoll(int cmsWait, Dispatcher* dispatcher) {
RTC_DCHECK(dispatcher);
int64_t tvWait = -1;
int64_t tvStop = -1;
if (cmsWait != kForever) {
tvWait = cmsWait;
tvStop = TimeAfter(cmsWait);
}
fWait_ = true;
struct pollfd fds = {0};
int fd = dispatcher->GetDescriptor();
fds.fd = fd;
while (fWait_) {
uint32_t ff = dispatcher->GetRequestedEvents();
fds.events = 0;
if (ff & (DE_READ | DE_ACCEPT)) {
fds.events |= POLLIN;
}
if (ff & (DE_WRITE | DE_CONNECT)) {
fds.events |= POLLOUT;
}
fds.revents = 0;
// Wait then call handlers as appropriate
// < 0 means error
// 0 means timeout
// > 0 means count of descriptors ready
int n = poll(&fds, 1, static_cast<int>(tvWait));
if (n < 0) {
if (errno != EINTR) {
RTC_LOG_E(LS_ERROR, EN, errno) << "poll";
return false;
}
// Else ignore the error and keep going. If this EINTR was for one of the
// signals managed by this PhysicalSocketServer, the
// PosixSignalDeliveryDispatcher will be in the signaled state in the next
// iteration.
} else if (n == 0) {
// If timeout, return success
return true;
} else {
// We have signaled descriptors (should only be the passed dispatcher).
RTC_DCHECK_EQ(n, 1);
RTC_DCHECK_EQ(fds.fd, fd);
bool readable = (fds.revents & (POLLIN | POLLPRI));
bool writable = (fds.revents & POLLOUT);
bool check_error = (fds.revents & (POLLRDHUP | POLLERR | POLLHUP));
ProcessEvents(dispatcher, readable, writable, check_error);
}
if (cmsWait != kForever) {
tvWait = TimeDiff(tvStop, TimeMillis());
if (tvWait < 0) {
// Return success on timeout.
return true;
}
}
}
return true;
}
#endif // WEBRTC_USE_EPOLL
#endif // WEBRTC_POSIX
#if defined(WEBRTC_WIN)
bool PhysicalSocketServer::Wait(int cmsWait, bool process_io) {
// We don't support reentrant waiting.
RTC_DCHECK(!waiting_);
ScopedSetTrue s(&waiting_);
int64_t cmsTotal = cmsWait;
int64_t cmsElapsed = 0;
int64_t msStart = Time();
fWait_ = true;
while (fWait_) {
std::vector<WSAEVENT> events;
std::vector<uint64_t> event_owners;
events.push_back(socket_ev_);
{
CritScope cr(&crit_);
// Get a snapshot of all current dispatchers; this is used to avoid the
// ABA problem (see later comment) and avoids the dispatcher_by_key_
// iterator being invalidated by calling CheckSignalClose, which may
// remove the dispatcher from the list.
current_dispatcher_keys_.clear();
for (auto const& kv : dispatcher_by_key_) {
current_dispatcher_keys_.push_back(kv.first);
}
for (uint64_t key : current_dispatcher_keys_) {
if (!dispatcher_by_key_.count(key)) {
continue;
}
Dispatcher* disp = dispatcher_by_key_.at(key);
if (!disp)
continue;
if (!process_io && (disp != signal_wakeup_))
continue;
SOCKET s = disp->GetSocket();
if (disp->CheckSignalClose()) {
// We just signalled close, don't poll this socket.
} else if (s != INVALID_SOCKET) {
WSAEventSelect(s, events[0],
FlagsToEvents(disp->GetRequestedEvents()));
} else {
events.push_back(disp->GetWSAEvent());
event_owners.push_back(key);
}
}
}
// Which is shorter, the delay wait or the asked wait?
int64_t cmsNext;
if (cmsWait == kForever) {
cmsNext = cmsWait;
} else {
cmsNext = std::max<int64_t>(0, cmsTotal - cmsElapsed);
}
// Wait for one of the events to signal
DWORD dw =
WSAWaitForMultipleEvents(static_cast<DWORD>(events.size()), &events[0],
false, static_cast<DWORD>(cmsNext), false);
if (dw == WSA_WAIT_FAILED) {
// Failed?
// TODO(pthatcher): need a better strategy than this!
WSAGetLastError();
RTC_NOTREACHED();
return false;
} else if (dw == WSA_WAIT_TIMEOUT) {
// Timeout?
return true;
} else {
// Figure out which one it is and call it
CritScope cr(&crit_);
int index = dw - WSA_WAIT_EVENT_0;
if (index > 0) {
--index; // The first event is the socket event
uint64_t key = event_owners[index];
if (!dispatcher_by_key_.count(key)) {
// The dispatcher could have been removed while waiting for events.
continue;
}
Dispatcher* disp = dispatcher_by_key_.at(key);
disp->OnPreEvent(0);
disp->OnEvent(0, 0);
} else if (process_io) {
// Iterate only on the dispatchers whose sockets were passed into
// WSAEventSelect; this avoids the ABA problem (a socket being
// destroyed and a new one created with the same SOCKET handle).
for (uint64_t key : current_dispatcher_keys_) {
if (!dispatcher_by_key_.count(key)) {
continue;
}
Dispatcher* disp = dispatcher_by_key_.at(key);
SOCKET s = disp->GetSocket();
if (s == INVALID_SOCKET)
continue;
WSANETWORKEVENTS wsaEvents;
int err = WSAEnumNetworkEvents(s, events[0], &wsaEvents);
if (err == 0) {
{
if ((wsaEvents.lNetworkEvents & FD_READ) &&
wsaEvents.iErrorCode[FD_READ_BIT] != 0) {
RTC_LOG(WARNING)
<< "PhysicalSocketServer got FD_READ_BIT error "
<< wsaEvents.iErrorCode[FD_READ_BIT];
}
if ((wsaEvents.lNetworkEvents & FD_WRITE) &&
wsaEvents.iErrorCode[FD_WRITE_BIT] != 0) {
RTC_LOG(WARNING)
<< "PhysicalSocketServer got FD_WRITE_BIT error "
<< wsaEvents.iErrorCode[FD_WRITE_BIT];
}
if ((wsaEvents.lNetworkEvents & FD_CONNECT) &&
wsaEvents.iErrorCode[FD_CONNECT_BIT] != 0) {
RTC_LOG(WARNING)
<< "PhysicalSocketServer got FD_CONNECT_BIT error "
<< wsaEvents.iErrorCode[FD_CONNECT_BIT];
}
if ((wsaEvents.lNetworkEvents & FD_ACCEPT) &&
wsaEvents.iErrorCode[FD_ACCEPT_BIT] != 0) {
RTC_LOG(WARNING)
<< "PhysicalSocketServer got FD_ACCEPT_BIT error "
<< wsaEvents.iErrorCode[FD_ACCEPT_BIT];
}
if ((wsaEvents.lNetworkEvents & FD_CLOSE) &&
wsaEvents.iErrorCode[FD_CLOSE_BIT] != 0) {
RTC_LOG(WARNING)
<< "PhysicalSocketServer got FD_CLOSE_BIT error "
<< wsaEvents.iErrorCode[FD_CLOSE_BIT];
}
}
uint32_t ff = 0;
int errcode = 0;
if (wsaEvents.lNetworkEvents & FD_READ)
ff |= DE_READ;
if (wsaEvents.lNetworkEvents & FD_WRITE)
ff |= DE_WRITE;
if (wsaEvents.lNetworkEvents & FD_CONNECT) {
if (wsaEvents.iErrorCode[FD_CONNECT_BIT] == 0) {
ff |= DE_CONNECT;
} else {
ff |= DE_CLOSE;
errcode = wsaEvents.iErrorCode[FD_CONNECT_BIT];
}
}
if (wsaEvents.lNetworkEvents & FD_ACCEPT)
ff |= DE_ACCEPT;
if (wsaEvents.lNetworkEvents & FD_CLOSE) {
ff |= DE_CLOSE;
errcode = wsaEvents.iErrorCode[FD_CLOSE_BIT];
}
if (ff != 0) {
disp->OnPreEvent(ff);
disp->OnEvent(ff, errcode);
}
}
}
}
// Reset the network event until new activity occurs
WSAResetEvent(socket_ev_);
}
// Break?
if (!fWait_)
break;
cmsElapsed = TimeSince(msStart);
if ((cmsWait != kForever) && (cmsElapsed >= cmsWait)) {
break;
}
}
// Done
return true;
}
#endif // WEBRTC_WIN
} // namespace rtc
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