replicant-frameworks_native/libs/gui/BitTube.cpp
Mathias Agopian 7b5be95cb3 use a socketpair instead of a pipe in BitTube
Bug: 6252830
Change-Id: Ia7a7b08409517214136261c05569dc5959a597ab
2012-04-02 18:41:10 -07:00

176 lines
4.8 KiB
C++

/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdint.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <unistd.h>
#include <utils/Errors.h>
#include <binder/Parcel.h>
#include <gui/BitTube.h>
namespace android {
// ----------------------------------------------------------------------------
// Socket buffer size. The default is typically about 128KB, which is much larger than
// we really need. So we make it smaller.
static const size_t SOCKET_BUFFER_SIZE = 4 * 1024;
BitTube::BitTube()
: mSendFd(-1), mReceiveFd(-1)
{
int sockets[2];
if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) == 0) {
int size = SOCKET_BUFFER_SIZE;
setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
fcntl(sockets[0], F_SETFL, O_NONBLOCK);
fcntl(sockets[1], F_SETFL, O_NONBLOCK);
mReceiveFd = sockets[0];
mSendFd = sockets[1];
} else {
mReceiveFd = -errno;
ALOGE("BitTube: pipe creation failed (%s)", strerror(-mReceiveFd));
}
}
BitTube::BitTube(const Parcel& data)
: mSendFd(-1), mReceiveFd(-1)
{
mReceiveFd = dup(data.readFileDescriptor());
if (mReceiveFd >= 0) {
int size = SOCKET_BUFFER_SIZE;
setsockopt(mReceiveFd, SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
setsockopt(mReceiveFd, SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
fcntl(mReceiveFd, F_SETFL, O_NONBLOCK);
} else {
mReceiveFd = -errno;
ALOGE("BitTube(Parcel): can't dup filedescriptor (%s)",
strerror(-mReceiveFd));
}
}
BitTube::~BitTube()
{
if (mSendFd >= 0)
close(mSendFd);
if (mReceiveFd >= 0)
close(mReceiveFd);
}
status_t BitTube::initCheck() const
{
if (mReceiveFd < 0) {
return status_t(mReceiveFd);
}
return NO_ERROR;
}
int BitTube::getFd() const
{
return mReceiveFd;
}
ssize_t BitTube::write(void const* vaddr, size_t size)
{
ssize_t err, len;
do {
len = ::send(mSendFd, vaddr, size, MSG_DONTWAIT | MSG_NOSIGNAL);
err = len < 0 ? errno : 0;
} while (err == EINTR);
return err == 0 ? len : -err;
}
ssize_t BitTube::read(void* vaddr, size_t size)
{
ssize_t err, len;
do {
len = ::recv(mReceiveFd, vaddr, size, MSG_DONTWAIT);
err = len < 0 ? errno : 0;
} while (err == EINTR);
if (err == EAGAIN || err == EWOULDBLOCK) {
// EAGAIN means that we have non-blocking I/O but there was
// no data to be read. Nothing the client should care about.
return 0;
}
return err == 0 ? len : -err;
}
status_t BitTube::writeToParcel(Parcel* reply) const
{
if (mReceiveFd < 0)
return -EINVAL;
status_t result = reply->writeDupFileDescriptor(mReceiveFd);
close(mReceiveFd);
mReceiveFd = -1;
return result;
}
ssize_t BitTube::sendObjects(const sp<BitTube>& tube,
void const* events, size_t count, size_t objSize)
{
ssize_t numObjects = 0;
for (size_t i=0 ; i<count ; i++) {
const char* vaddr = reinterpret_cast<const char*>(events) + objSize * i;
ssize_t size = tube->write(vaddr, objSize);
if (size < 0) {
// error occurred
numObjects = -size;
break;
} else if (size == 0) {
// no more space
break;
}
numObjects++;
}
return numObjects;
}
ssize_t BitTube::recvObjects(const sp<BitTube>& tube,
void* events, size_t count, size_t objSize)
{
ssize_t numObjects = 0;
for (size_t i=0 ; i<count ; i++) {
char* vaddr = reinterpret_cast<char*>(events) + objSize * i;
ssize_t size = tube->read(vaddr, objSize);
if (size < 0) {
// error occurred
numObjects = -size;
break;
} else if (size == 0) {
// no more messages
break;
}
numObjects++;
}
return numObjects;
}
// ----------------------------------------------------------------------------
}; // namespace android