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/*
* Copyright (C) 2014-2018 Team Kodi
* This file is part of Kodi - https://kodi.tv
*
* SPDX-License-Identifier: GPL-2.0-or-later
* See LICENSES/README.md for more information.
*/
#include "FDEventMonitor.h"
#include "threads/SingleLock.h"
#include "utils/log.h"
#include <errno.h>
#include <mutex>
#include <poll.h>
#include <sys/eventfd.h>
#include <unistd.h>
#include "PlatformDefs.h"
CFDEventMonitor::CFDEventMonitor() :
CThread("FDEventMonitor")
{
}
CFDEventMonitor::~CFDEventMonitor()
{
std::unique_lock<CCriticalSection> lock(m_mutex);
InterruptPoll();
if (m_wakeupfd >= 0)
{
/* sets m_bStop */
StopThread(false);
/* wake up the poll() call */
eventfd_write(m_wakeupfd, 1);
/* Wait for the thread to stop */
{
CSingleExit exit(m_mutex);
StopThread(true);
}
close(m_wakeupfd);
}
}
void CFDEventMonitor::AddFD(const MonitoredFD& monitoredFD, int& id)
{
std::unique_lock<CCriticalSection> lock(m_mutex);
InterruptPoll();
AddFDLocked(monitoredFD, id);
StartMonitoring();
}
void CFDEventMonitor::AddFDs(const std::vector<MonitoredFD>& monitoredFDs,
std::vector<int>& ids)
{
std::unique_lock<CCriticalSection> lock(m_mutex);
InterruptPoll();
for (unsigned int i = 0; i < monitoredFDs.size(); ++i)
{
int id;
AddFDLocked(monitoredFDs[i], id);
ids.push_back(id);
}
StartMonitoring();
}
void CFDEventMonitor::RemoveFD(int id)
{
std::unique_lock<CCriticalSection> lock(m_mutex);
InterruptPoll();
if (m_monitoredFDs.erase(id) != 1)
{
CLog::Log(LOGERROR, "CFDEventMonitor::RemoveFD - Tried to remove non-existing monitoredFD {}",
id);
}
UpdatePollDescs();
}
void CFDEventMonitor::RemoveFDs(const std::vector<int>& ids)
{
std::unique_lock<CCriticalSection> lock(m_mutex);
InterruptPoll();
for (unsigned int i = 0; i < ids.size(); ++i)
{
if (m_monitoredFDs.erase(ids[i]) != 1)
{
CLog::Log(LOGERROR,
"CFDEventMonitor::RemoveFDs - Tried to remove non-existing monitoredFD {} while "
"removing {} FDs",
ids[i], (unsigned)ids.size());
}
}
UpdatePollDescs();
}
void CFDEventMonitor::Process()
{
eventfd_t dummy;
while (!m_bStop)
{
std::unique_lock<CCriticalSection> lock(m_mutex);
std::unique_lock<CCriticalSection> pollLock(m_pollMutex);
/*
* Leave the main mutex here to allow another thread to
* lock it while we are in poll().
* By then calling InterruptPoll() the other thread can
* wake up poll and wait for the processing to pause at
* the above lock(m_mutex).
*/
lock.unlock();
int err = poll(&m_pollDescs[0], m_pollDescs.size(), -1);
if (err < 0 && errno != EINTR)
{
CLog::Log(LOGERROR, "CFDEventMonitor::Process - poll() failed, error {}, stopping monitoring",
errno);
StopThread(false);
}
// Something woke us up - either there is data available or we are being
// paused/stopped via m_wakeupfd.
for (unsigned int i = 0; i < m_pollDescs.size(); ++i)
{
struct pollfd& pollDesc = m_pollDescs[i];
int id = m_monitoredFDbyPollDescs[i];
const MonitoredFD& monitoredFD = m_monitoredFDs[id];
if (pollDesc.revents)
{
if (monitoredFD.callback)
{
monitoredFD.callback(id, pollDesc.fd, pollDesc.revents,
monitoredFD.callbackData);
}
if (pollDesc.revents & (POLLERR | POLLHUP | POLLNVAL))
{
CLog::Log(LOGERROR,
"CFDEventMonitor::Process - polled fd {} got revents 0x{:x}, removing it",
pollDesc.fd, pollDesc.revents);
/* Probably would be nice to inform our caller that their FD was
* dropped, but oh well... */
m_monitoredFDs.erase(id);
UpdatePollDescs();
}
pollDesc.revents = 0;
}
}
/* flush wakeup fd */
eventfd_read(m_wakeupfd, &dummy);
}
}
void CFDEventMonitor::AddFDLocked(const MonitoredFD& monitoredFD, int& id)
{
id = m_nextID;
while (m_monitoredFDs.count(id))
{
++id;
}
m_nextID = id + 1;
m_monitoredFDs[id] = monitoredFD;
AddPollDesc(id, monitoredFD.fd, monitoredFD.events);
}
void CFDEventMonitor::AddPollDesc(int id, int fd, short events)
{
struct pollfd newPollFD;
newPollFD.fd = fd;
newPollFD.events = events;
newPollFD.revents = 0;
m_pollDescs.push_back(newPollFD);
m_monitoredFDbyPollDescs.push_back(id);
}
void CFDEventMonitor::UpdatePollDescs()
{
m_monitoredFDbyPollDescs.clear();
m_pollDescs.clear();
for (const auto& it : m_monitoredFDs)
{
AddPollDesc(it.first, it.second.fd, it.second.events);
}
}
void CFDEventMonitor::StartMonitoring()
{
if (!IsRunning())
{
/* Start the monitoring thread */
m_wakeupfd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
if (m_wakeupfd < 0)
{
CLog::Log(LOGERROR, "CFDEventMonitor::StartMonitoring - Failed to create eventfd, error {}",
errno);
return;
}
/* Add wakeup fd to the fd list */
int id;
AddFDLocked(MonitoredFD(m_wakeupfd, POLLIN, NULL, NULL), id);
Create(false);
}
}
void CFDEventMonitor::InterruptPoll()
{
if (m_wakeupfd >= 0)
{
eventfd_write(m_wakeupfd, 1);
/* wait for the poll() result handling (if any) to end */
std::unique_lock<CCriticalSection> pollLock(m_pollMutex);
}
}
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