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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsSocketTransportService2.h"
#include "PollableEvent.h"
#include "mozilla/Assertions.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Logging.h"
#include "prerror.h"
#include "prio.h"
#include "private/pprio.h"
#include "prnetdb.h"
#ifdef XP_WIN
# include "ShutdownLayer.h"
#else
# include <fcntl.h>
# define USEPIPE 1
#endif
namespace mozilla {
namespace net {
#ifndef USEPIPE
static PRDescIdentity sPollableEventLayerIdentity;
static PRIOMethods sPollableEventLayerMethods;
static PRIOMethods* sPollableEventLayerMethodsPtr = nullptr;
static void LazyInitSocket() {
MOZ_ASSERT(OnSocketThread(), "not on socket thread");
if (sPollableEventLayerMethodsPtr) {
return;
}
sPollableEventLayerIdentity = PR_GetUniqueIdentity("PollableEvent Layer");
sPollableEventLayerMethods = *PR_GetDefaultIOMethods();
sPollableEventLayerMethodsPtr = &sPollableEventLayerMethods;
}
static bool NewTCPSocketPair(PRFileDesc* fd[], bool aSetRecvBuff) {
// this is a replacement for PR_NewTCPSocketPair that manually
// sets the recv buffer to 64K. A windows bug (1248358)
// can result in using an incompatible rwin and window
// scale option on localhost pipes if not set before connect.
SOCKET_LOG(("NewTCPSocketPair %s a recv buffer tuning\n",
aSetRecvBuff ? "with" : "without"));
PRFileDesc* listener = nullptr;
PRFileDesc* writer = nullptr;
PRFileDesc* reader = nullptr;
PRSocketOptionData recvBufferOpt;
recvBufferOpt.option = PR_SockOpt_RecvBufferSize;
recvBufferOpt.value.recv_buffer_size = 65535;
PRSocketOptionData nodelayOpt;
nodelayOpt.option = PR_SockOpt_NoDelay;
nodelayOpt.value.no_delay = true;
PRSocketOptionData noblockOpt;
noblockOpt.option = PR_SockOpt_Nonblocking;
noblockOpt.value.non_blocking = true;
listener = PR_OpenTCPSocket(PR_AF_INET);
if (!listener) {
goto failed;
}
if (aSetRecvBuff) {
PR_SetSocketOption(listener, &recvBufferOpt);
}
PR_SetSocketOption(listener, &nodelayOpt);
PRNetAddr listenAddr;
memset(&listenAddr, 0, sizeof(listenAddr));
if ((PR_InitializeNetAddr(PR_IpAddrLoopback, 0, &listenAddr) == PR_FAILURE) ||
(PR_Bind(listener, &listenAddr) == PR_FAILURE) ||
(PR_GetSockName(listener, &listenAddr) ==
PR_FAILURE) || // learn the dynamic port
(PR_Listen(listener, 5) == PR_FAILURE)) {
goto failed;
}
writer = PR_OpenTCPSocket(PR_AF_INET);
if (!writer) {
goto failed;
}
if (aSetRecvBuff) {
PR_SetSocketOption(writer, &recvBufferOpt);
}
PR_SetSocketOption(writer, &nodelayOpt);
PR_SetSocketOption(writer, &noblockOpt);
PRNetAddr writerAddr;
if (PR_InitializeNetAddr(PR_IpAddrLoopback, ntohs(listenAddr.inet.port),
&writerAddr) == PR_FAILURE) {
goto failed;
}
if (PR_Connect(writer, &writerAddr, PR_INTERVAL_NO_TIMEOUT) == PR_FAILURE) {
if ((PR_GetError() != PR_IN_PROGRESS_ERROR) ||
(PR_ConnectContinue(writer, PR_POLL_WRITE) == PR_FAILURE)) {
goto failed;
}
}
PR_SetFDInheritable(writer, false);
reader = PR_Accept(listener, &listenAddr, PR_MillisecondsToInterval(200));
if (!reader) {
goto failed;
}
PR_SetFDInheritable(reader, false);
if (aSetRecvBuff) {
PR_SetSocketOption(reader, &recvBufferOpt);
}
PR_SetSocketOption(reader, &nodelayOpt);
PR_SetSocketOption(reader, &noblockOpt);
PR_Close(listener);
fd[0] = reader;
fd[1] = writer;
return true;
failed:
if (listener) {
PR_Close(listener);
}
if (reader) {
PR_Close(reader);
}
if (writer) {
PR_Close(writer);
}
return false;
}
#endif
PollableEvent::PollableEvent()
: mWriteFD(nullptr),
mReadFD(nullptr),
mSignaled(false),
mWriteFailed(false),
mSignalTimestampAdjusted(false) {
MOZ_COUNT_CTOR(PollableEvent);
MOZ_ASSERT(OnSocketThread(), "not on socket thread");
// create pair of prfiledesc that can be used as a poll()ble
// signal. on windows use a localhost socket pair, and on
// unix use a pipe.
#ifdef USEPIPE
SOCKET_LOG(("PollableEvent() using pipe\n"));
if (PR_CreatePipe(&mReadFD, &mWriteFD) == PR_SUCCESS) {
// make the pipe non blocking. NSPR asserts at
// trying to use SockOpt here
PROsfd fd = PR_FileDesc2NativeHandle(mReadFD);
int flags = fcntl(fd, F_GETFL, 0);
(void)fcntl(fd, F_SETFL, flags | O_NONBLOCK);
fd = PR_FileDesc2NativeHandle(mWriteFD);
flags = fcntl(fd, F_GETFL, 0);
(void)fcntl(fd, F_SETFL, flags | O_NONBLOCK);
} else {
mReadFD = nullptr;
mWriteFD = nullptr;
SOCKET_LOG(("PollableEvent() pipe failed\n"));
}
#else
SOCKET_LOG(("PollableEvent() using socket pair\n"));
PRFileDesc* fd[2];
LazyInitSocket();
// Try with a increased recv buffer first (bug 1248358).
if (NewTCPSocketPair(fd, true)) {
mReadFD = fd[0];
mWriteFD = fd[1];
// If the previous fails try without recv buffer increase (bug 1305436).
} else if (NewTCPSocketPair(fd, false)) {
mReadFD = fd[0];
mWriteFD = fd[1];
// If both fail, try the old version.
} else if (PR_NewTCPSocketPair(fd) == PR_SUCCESS) {
mReadFD = fd[0];
mWriteFD = fd[1];
PRSocketOptionData socket_opt;
DebugOnly<PRStatus> status;
socket_opt.option = PR_SockOpt_NoDelay;
socket_opt.value.no_delay = true;
PR_SetSocketOption(mWriteFD, &socket_opt);
PR_SetSocketOption(mReadFD, &socket_opt);
socket_opt.option = PR_SockOpt_Nonblocking;
socket_opt.value.non_blocking = true;
status = PR_SetSocketOption(mWriteFD, &socket_opt);
MOZ_ASSERT(status == PR_SUCCESS);
status = PR_SetSocketOption(mReadFD, &socket_opt);
MOZ_ASSERT(status == PR_SUCCESS);
}
if (mReadFD && mWriteFD) {
// compatibility with LSPs such as McAfee that assume a NSPR
// layer for read ala the nspr Pollable Event - Bug 698882. This layer is a
// nop.
PRFileDesc* topLayer = PR_CreateIOLayerStub(sPollableEventLayerIdentity,
sPollableEventLayerMethodsPtr);
if (topLayer) {
if (PR_PushIOLayer(fd[0], PR_TOP_IO_LAYER, topLayer) == PR_FAILURE) {
topLayer->dtor(topLayer);
} else {
SOCKET_LOG(("PollableEvent() nspr layer ok\n"));
mReadFD = topLayer;
}
}
} else {
SOCKET_LOG(("PollableEvent() socketpair failed\n"));
}
#endif
if (mReadFD && mWriteFD) {
// prime the system to deal with races invovled in [dc]tor cycle
SOCKET_LOG(("PollableEvent() ctor ok\n"));
mSignaled = true;
MarkFirstSignalTimestamp();
PR_Write(mWriteFD, "I", 1);
}
}
PollableEvent::~PollableEvent() {
MOZ_COUNT_DTOR(PollableEvent);
if (mWriteFD) {
#if defined(XP_WIN)
AttachShutdownLayer(mWriteFD);
#endif
PR_Close(mWriteFD);
}
if (mReadFD) {
#if defined(XP_WIN)
AttachShutdownLayer(mReadFD);
#endif
PR_Close(mReadFD);
}
}
// we do not record signals on the socket thread
// because the socket thread can reliably look at its
// own runnable queue before selecting a poll time
// this is the "service the network without blocking" comment in
// nsSocketTransportService2.cpp
bool PollableEvent::Signal() {
SOCKET_LOG(("PollableEvent::Signal\n"));
if (!mWriteFD) {
SOCKET_LOG(("PollableEvent::Signal Failed on no FD\n"));
return false;
}
#ifndef XP_WIN
// On windows poll can hang and this became worse when we introduced the
// patch for bug 698882 (see also bug 1292181), therefore we reverted the
// behavior on windows to be as before bug 698882, e.g. write to the socket
// also if an event dispatch is on the socket thread and writing to the
// socket for each event. See bug 1292181.
if (OnSocketThread()) {
SOCKET_LOG(("PollableEvent::Signal OnSocketThread nop\n"));
return true;
}
#endif
#ifndef XP_WIN
// To wake up the poll writing once is enough, but for Windows that can cause
// hangs so we will write for every event.
// For non-Windows systems it is enough to write just once.
if (mSignaled) {
return true;
}
#endif
if (!mSignaled) {
mSignaled = true;
MarkFirstSignalTimestamp();
}
int32_t status = PR_Write(mWriteFD, "M", 1);
SOCKET_LOG(("PollableEvent::Signal PR_Write %d\n", status));
if (status != 1) {
NS_WARNING("PollableEvent::Signal Failed\n");
SOCKET_LOG(("PollableEvent::Signal Failed\n"));
mSignaled = false;
mWriteFailed = true;
} else {
mWriteFailed = false;
}
return (status == 1);
}
bool PollableEvent::Clear() {
// necessary because of the "dont signal on socket thread" optimization
MOZ_ASSERT(OnSocketThread(), "not on socket thread");
SOCKET_LOG(("PollableEvent::Clear\n"));
if (!mFirstSignalAfterClear.IsNull()) {
SOCKET_LOG(("PollableEvent::Clear time to signal %ums",
(uint32_t)(TimeStamp::NowLoRes() - mFirstSignalAfterClear)
.ToMilliseconds()));
}
mFirstSignalAfterClear = TimeStamp();
mSignalTimestampAdjusted = false;
mSignaled = false;
if (!mReadFD) {
SOCKET_LOG(("PollableEvent::Clear mReadFD is null\n"));
return false;
}
char buf[2048];
int32_t status;
#ifdef XP_WIN
// On Windows we are writing to the socket for each event, to be sure that we
// do not have any deadlock read from the socket as much as we can.
while (true) {
status = PR_Read(mReadFD, buf, 2048);
SOCKET_LOG(("PollableEvent::Clear PR_Read %d\n", status));
if (status == 0) {
SOCKET_LOG(("PollableEvent::Clear EOF!\n"));
return false;
}
if (status < 0) {
PRErrorCode code = PR_GetError();
if (code == PR_WOULD_BLOCK_ERROR) {
return true;
} else {
SOCKET_LOG(("PollableEvent::Clear unexpected error %d\n", code));
return false;
}
}
}
#else
status = PR_Read(mReadFD, buf, 2048);
SOCKET_LOG(("PollableEvent::Clear PR_Read %d\n", status));
if (status == 1) {
return true;
}
if (status == 0) {
SOCKET_LOG(("PollableEvent::Clear EOF!\n"));
return false;
}
if (status > 1) {
MOZ_ASSERT(false);
SOCKET_LOG(("PollableEvent::Clear Unexpected events\n"));
Clear();
return true;
}
PRErrorCode code = PR_GetError();
if (code == PR_WOULD_BLOCK_ERROR) {
return true;
}
SOCKET_LOG(("PollableEvent::Clear unexpected error %d\n", code));
return false;
#endif // XP_WIN
}
void PollableEvent::MarkFirstSignalTimestamp() {
if (mFirstSignalAfterClear.IsNull()) {
SOCKET_LOG(("PollableEvent::MarkFirstSignalTimestamp"));
mFirstSignalAfterClear = TimeStamp::NowLoRes();
}
}
void PollableEvent::AdjustFirstSignalTimestamp() {
if (!mSignalTimestampAdjusted && !mFirstSignalAfterClear.IsNull()) {
SOCKET_LOG(("PollableEvent::AdjustFirstSignalTimestamp"));
mFirstSignalAfterClear = TimeStamp::NowLoRes();
mSignalTimestampAdjusted = true;
}
}
bool PollableEvent::IsSignallingAlive(TimeDuration const& timeout) {
if (mWriteFailed) {
return false;
}
#ifdef DEBUG
// The timeout would be just a disturbance in a debug build.
return true;
#else
if (!mSignaled || mFirstSignalAfterClear.IsNull() ||
timeout == TimeDuration()) {
return true;
}
TimeDuration delay = (TimeStamp::NowLoRes() - mFirstSignalAfterClear);
bool timedOut = delay > timeout;
return !timedOut;
#endif // DEBUG
}
} // namespace net
} // namespace mozilla