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NonBlockingUnixCommunicationSocket.cpp
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NonBlockingUnixCommunicationSocket.cpp
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/*
* Copyright (C) 2011-2018 Intel Corporation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef __STDC_LIMIT_MACROS
#define __STDC_LIMIT_MACROS
#endif
#include <stdint.h>
#include <NonBlockingUnixCommunicationSocket.h>
#include <arch.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/epoll.h>
#include <string.h>
#include <se_trace.h>
NonBlockingUnixCommunicationSocket::~NonBlockingUnixCommunicationSocket()
{
if (mEvents != NULL)
delete [] mEvents;
close(mEpoll);
close(mCommandPipe[0]);
close(mCommandPipe[1]);
}
se_static_assert(MAX_EVENTS<=UINT32_MAX/sizeof(struct epoll_event));
bool NonBlockingUnixCommunicationSocket::init()
{
//create the epoll structure
mEpoll = epoll_create(1);
if (mEpoll < 0)
return false;
//create the command pipe
int ret;
ret = pipe(mCommandPipe);
if (ret != 0)
{
close(mEpoll);
return false;
}
//place one end of the pipe in the epoll list
struct epoll_event event;
event.data.fd = mCommandPipe[0];
event.events = EPOLLIN | EPOLLET;
int registerCommand = epoll_ctl (mEpoll, EPOLL_CTL_ADD, mCommandPipe[0], &event);
//connect to the AESM - blocking connect
bool connectInit = UnixCommunicationSocket::init();
//register the event
event.data.fd = mSocket;
event.events = EPOLLET;
int registerSocket = epoll_ctl (mEpoll, EPOLL_CTL_ADD, mSocket, &event);
if (registerCommand != 0 || registerSocket != 0 || connectInit == false)
{
close(mEpoll);
close(mCommandPipe[0]);
close(mCommandPipe[1]);
return false;
}
//create events buffer
mEvents = new struct epoll_event[MAX_EVENTS];
memset((char*)mEvents, 0, MAX_EVENTS * sizeof(struct epoll_event));
return MakeNonBlocking();
}
char* NonBlockingUnixCommunicationSocket::readRaw(ssize_t length)
{
if (mSocket == -1)
return NULL;
// Add read event
struct epoll_event event;
event.data.fd = mSocket;
event.events = EPOLLIN | EPOLLET;
int registerSocket = epoll_ctl (mEpoll, EPOLL_CTL_MOD, mSocket, &event);
if (registerSocket != 0)
{
return NULL;
}
ssize_t total_read = 0;
ssize_t step = 0;
char * recBuf = NULL;
recBuf = new char[length];
memset(recBuf, 0, length);
int32_t epollTimeout = (mTimeoutMseconds > 0 ? mTimeoutMseconds : -1);
int eventNum = 0;
int i = 0;
bool errorDetected = false;
bool cancellationDetected = false;
bool peerSocketClosed = false;
MarkStartTime();
do{
//try a direct read (maybe all data is available already)
step = read(mSocket, recBuf, length);
if(step == -1 && errno == EINTR && CheckForTimeout() == false){
SE_TRACE_WARNING("read is interrupted by signal\n");
continue;
}
if (step == -1 && errno != EAGAIN)
{
errorDetected = true;
}
else
{
if (step != -1)
{
total_read += step;
}
if (total_read == length)
{
break; //we are finished here
}
}
//wait for events
do {
eventNum = epoll_wait(mEpoll, mEvents, MAX_EVENTS, epollTimeout);
} while (eventNum == -1 && errno == EINTR && CheckForTimeout() == false);
if (eventNum == -1)
{
errorDetected = true;
}
for (i = 0;
CheckForTimeout() == false && //need to be sure to check this first
errorDetected == false &&
cancellationDetected == false &&
peerSocketClosed == false &&
i < eventNum;
i++)
{
if (mEvents[i].events & EPOLLHUP)
{
peerSocketClosed = true;
//peer closed socket. one more reading all remaining data.
}
if ((mEvents[i].events & EPOLLERR) ||
(!(mEvents[i].events & EPOLLIN)))
{
//error
errorDetected = true;
}
else
{
if (mEvents[i].data.fd == mCommandPipe[0])
{
//cancellation -- in the case this logic would complicate by needing more commands, we will detach this into
//a CommandManager of some sort
cancellationDetected = true;
}
else
{
//read data
step = partialRead(recBuf + total_read, length - total_read);
if (step == -1)
{
errorDetected = true;
}
if (step == 0) //peer closed socket
{
//did this happen before getting the entire data ?
if (total_read != length)
errorDetected = true;
}
total_read += step;
}
}
}
if (total_read != length)
{
if (errorDetected || cancellationDetected || wasTimeoutDetected())
{
disconnect();
delete [] recBuf;
recBuf = NULL;
break;
}
}
//clear events
memset((char*)mEvents, 0, MAX_EVENTS * sizeof(struct epoll_event));
}while (total_read < length);
if(mSocket!=-1)
{
event.data.fd = mSocket;
event.events = EPOLLET;
registerSocket = epoll_ctl (mEpoll, EPOLL_CTL_MOD, mSocket, &event);
if (registerSocket != 0)
{
disconnect();
if (NULL != recBuf)
delete [] recBuf;
return NULL;
}
}else
{
// disconnected, recBuf is set NULL when disconnect() is called.
}
return recBuf;
}
/**
* Read no more than maxLength bytes
*/
ssize_t NonBlockingUnixCommunicationSocket::partialRead(char* buffer, ssize_t maxLength)
{
ssize_t step = 0;
ssize_t chunkSize = (maxLength < 512 ? maxLength : 512);
ssize_t totalRead = 0;
ssize_t remaining = maxLength;
while (totalRead < maxLength)
{
remaining = maxLength - totalRead;
step = read(mSocket, buffer + totalRead, (remaining > chunkSize ? chunkSize : remaining));
if(step == -1 && errno == EINTR && CheckForTimeout() == false){
SE_TRACE_WARNING("read was interrupted by signal\n");
continue;
}
if (step == -1)
{
if (errno != EAGAIN)
return -1;
break;
}
totalRead += step;
if (step == 0)
break;
}
return totalRead;
}
ssize_t NonBlockingUnixCommunicationSocket::writeRaw(const char* data, ssize_t length)
{
if (mSocket == -1)
return -1;
ssize_t total_write = 0;
ssize_t step = 0;
int32_t epollTimeout = (mTimeoutMseconds > 0 ? mTimeoutMseconds : -1);
int eventNum = 0;
int i = 0;
bool errorDetected = false;
bool cancellationDetected = false;
bool peerSocketClosed = false;
bool lastWriteSuccessful = false;
struct epoll_event event;
int registerSocket;
MarkStartTime();
do
{
step = write(mSocket, data + total_write, length - total_write);
if(step == -1 && errno == EINTR && CheckForTimeout() == false){
SE_TRACE_WARNING("write was interrupted by signal\n");
continue;
}
if (step == -1 && errno != EAGAIN)
{
// an error occured
errorDetected = true;
}
else
{
if (step == -1 && errno == EAGAIN)
{
// the internal buffer is full
// EPOLLOUT is added so that an event is generated when there is
// empty space in the buffer
lastWriteSuccessful = false;
event.data.fd = mSocket;
event.events = EPOLLET | EPOLLOUT;
registerSocket = epoll_ctl (mEpoll, EPOLL_CTL_MOD, mSocket, &event);
if (registerSocket != 0)
{
return -1;
}
}
else
{
// the write was successful
if (!lastWriteSuccessful)
{
// remove EPOLLOUT
lastWriteSuccessful = true;
event.data.fd = mSocket;
event.events = EPOLLET;
registerSocket = epoll_ctl (mEpoll, EPOLL_CTL_MOD, mSocket, &event);
if (registerSocket != 0)
{
return -1;
}
}
total_write += step;
if (total_write == length)
{
break;
}
continue;
}
}
do {
eventNum = epoll_wait(mEpoll, mEvents, MAX_EVENTS, epollTimeout);
} while (eventNum == -1 && errno == EINTR && CheckForTimeout() == false);
if (eventNum == -1)
{
errorDetected = true;
}
for (i = 0;
CheckForTimeout() == false &&
errorDetected == false &&
cancellationDetected == false &&
peerSocketClosed == false &&
i < eventNum;
i++)
{
if (mEvents[i].events & EPOLLHUP)
{
// the socket or that pipe have been closed
peerSocketClosed = true;
continue;
}
if ((mEvents[i].events & EPOLLERR) ||
(!(mEvents[i].events & EPOLLOUT)))
{
// received an event other than EPOLLOUT
errorDetected = true;
}
else
{
if (mEvents[i].data.fd == mCommandPipe[0])
{
cancellationDetected = true;
}
}
}
if (errorDetected || cancellationDetected || wasTimeoutDetected() || peerSocketClosed)
{
disconnect();
break;
}
memset((char*)mEvents, 0, MAX_EVENTS * sizeof(struct epoll_event));
}
while(total_write < length);
if(mSocket!=-1){
event.data.fd = mSocket;
event.events = EPOLLET;
registerSocket = epoll_ctl (mEpoll, EPOLL_CTL_MOD, mSocket, &event);
if (registerSocket != 0)
{
return -1;
}
}else
{//disconneded due to error.
return -1;
}
return total_write;
}
int NonBlockingUnixCommunicationSocket::getSockDescriptor()
{
return UnixCommunicationSocket::getSockDescriptor();
}
bool NonBlockingUnixCommunicationSocket::wasTimeoutDetected()
{
return UnixCommunicationSocket::wasTimeoutDetected();
}
bool NonBlockingUnixCommunicationSocket::setTimeout(uint32_t milliseconds)
{
mTimeoutMseconds = milliseconds;
return true;
}
bool NonBlockingUnixCommunicationSocket::MakeNonBlocking()
{
int flags, ret;
flags = fcntl (mSocket, F_GETFL, 0);
if (flags == -1)
{
return false;
}
flags |= (int)O_NONBLOCK;
ret = fcntl (mSocket, F_SETFL, flags);
if (ret == -1)
{
return false;
}
return true;
}
void NonBlockingUnixCommunicationSocket::Cancel() const
{
//write anything on the pipe
char cmd = '1';
if (write(mCommandPipe[0],&cmd,1) < 0)
{
// do nothing
}
}