1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <private/gui/BitTube.h>
18
19#include <stdint.h>
20#include <sys/socket.h>
21#include <sys/types.h>
22
23#include <fcntl.h>
24#include <unistd.h>
25
26#include <utils/Errors.h>
27
28#include <binder/Parcel.h>
29
30namespace android {
31namespace gui {
32
33// Socket buffer size.  The default is typically about 128KB, which is much larger than we really
34// need. So we make it smaller.
35static const size_t DEFAULT_SOCKET_BUFFER_SIZE = 4 * 1024;
36
37BitTube::BitTube(size_t bufsize) {
38    init(bufsize, bufsize);
39}
40
41BitTube::BitTube(DefaultSizeType) : BitTube(DEFAULT_SOCKET_BUFFER_SIZE) {}
42
43BitTube::BitTube(const Parcel& data) {
44    readFromParcel(&data);
45}
46
47void BitTube::init(size_t rcvbuf, size_t sndbuf) {
48    int sockets[2];
49    if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) == 0) {
50        size_t size = DEFAULT_SOCKET_BUFFER_SIZE;
51        setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf));
52        setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
53        // since we don't use the "return channel", we keep it small...
54        setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
55        setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
56        fcntl(sockets[0], F_SETFL, O_NONBLOCK);
57        fcntl(sockets[1], F_SETFL, O_NONBLOCK);
58        mReceiveFd.reset(sockets[0]);
59        mSendFd.reset(sockets[1]);
60    } else {
61        mReceiveFd.reset();
62        ALOGE("BitTube: pipe creation failed (%s)", strerror(errno));
63    }
64}
65
66status_t BitTube::initCheck() const {
67    if (mReceiveFd < 0) {
68        return status_t(mReceiveFd);
69    }
70    return NO_ERROR;
71}
72
73int BitTube::getFd() const {
74    return mReceiveFd;
75}
76
77int BitTube::getSendFd() const {
78    return mSendFd;
79}
80
81base::unique_fd BitTube::moveReceiveFd() {
82    return std::move(mReceiveFd);
83}
84
85void BitTube::setReceiveFd(base::unique_fd&& receiveFd) {
86    mReceiveFd = std::move(receiveFd);
87}
88
89ssize_t BitTube::write(void const* vaddr, size_t size) {
90    ssize_t err, len;
91    do {
92        len = ::send(mSendFd, vaddr, size, MSG_DONTWAIT | MSG_NOSIGNAL);
93        // cannot return less than size, since we're using SOCK_SEQPACKET
94        err = len < 0 ? errno : 0;
95    } while (err == EINTR);
96    return err == 0 ? len : -err;
97}
98
99ssize_t BitTube::read(void* vaddr, size_t size) {
100    ssize_t err, len;
101    do {
102        len = ::recv(mReceiveFd, vaddr, size, MSG_DONTWAIT);
103        err = len < 0 ? errno : 0;
104    } while (err == EINTR);
105    if (err == EAGAIN || err == EWOULDBLOCK) {
106        // EAGAIN means that we have non-blocking I/O but there was no data to be read. Nothing the
107        // client should care about.
108        return 0;
109    }
110    return err == 0 ? len : -err;
111}
112
113status_t BitTube::writeToParcel(Parcel* reply) const {
114    if (mReceiveFd < 0) return -EINVAL;
115
116    status_t result = reply->writeDupFileDescriptor(mReceiveFd);
117    mReceiveFd.reset();
118    return result;
119}
120
121status_t BitTube::readFromParcel(const Parcel* parcel) {
122    mReceiveFd.reset(dup(parcel->readFileDescriptor()));
123    if (mReceiveFd < 0) {
124        mReceiveFd.reset();
125        int error = errno;
126        ALOGE("BitTube::readFromParcel: can't dup file descriptor (%s)", strerror(error));
127        return -error;
128    }
129    return NO_ERROR;
130}
131
132ssize_t BitTube::sendObjects(BitTube* tube, void const* events, size_t count, size_t objSize) {
133    const char* vaddr = reinterpret_cast<const char*>(events);
134    ssize_t size = tube->write(vaddr, count * objSize);
135
136    // should never happen because of SOCK_SEQPACKET
137    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
138                        "BitTube::sendObjects(count=%zu, size=%zu), res=%zd (partial events were "
139                        "sent!)",
140                        count, objSize, size);
141
142    // ALOGE_IF(size<0, "error %d sending %d events", size, count);
143    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
144}
145
146ssize_t BitTube::recvObjects(BitTube* tube, void* events, size_t count, size_t objSize) {
147    char* vaddr = reinterpret_cast<char*>(events);
148    ssize_t size = tube->read(vaddr, count * objSize);
149
150    // should never happen because of SOCK_SEQPACKET
151    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
152                        "BitTube::recvObjects(count=%zu, size=%zu), res=%zd (partial events were "
153                        "received!)",
154                        count, objSize, size);
155
156    // ALOGE_IF(size<0, "error %d receiving %d events", size, count);
157    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
158}
159
160} // namespace gui
161} // namespace android
162