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 <sensor/BitTube.h>
18
19#include <stdint.h>
20#include <sys/types.h>
21#include <sys/socket.h>
22
23#include <fcntl.h>
24#include <unistd.h>
25
26#include <binder/Parcel.h>
27
28namespace android {
29// ----------------------------------------------------------------------------
30
31// Socket buffer size.  The default is typically about 128KB, which is much larger than
32// we really need.  So we make it smaller.
33static const size_t DEFAULT_SOCKET_BUFFER_SIZE = 4 * 1024;
34
35
36BitTube::BitTube()
37    : mSendFd(-1), mReceiveFd(-1)
38{
39    init(DEFAULT_SOCKET_BUFFER_SIZE, DEFAULT_SOCKET_BUFFER_SIZE);
40}
41
42BitTube::BitTube(size_t bufsize)
43    : mSendFd(-1), mReceiveFd(-1)
44{
45    init(bufsize, bufsize);
46}
47
48BitTube::BitTube(const Parcel& data)
49    : mSendFd(-1), mReceiveFd(-1)
50{
51    mReceiveFd = dup(data.readFileDescriptor());
52    if (mReceiveFd < 0) {
53        mReceiveFd = -errno;
54        ALOGE("BitTube(Parcel): can't dup filedescriptor (%s)",
55                strerror(-mReceiveFd));
56    }
57}
58
59BitTube::~BitTube()
60{
61    if (mSendFd >= 0)
62        close(mSendFd);
63
64    if (mReceiveFd >= 0)
65        close(mReceiveFd);
66}
67
68void BitTube::init(size_t rcvbuf, size_t sndbuf) {
69    int sockets[2];
70    if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) == 0) {
71        size_t size = DEFAULT_SOCKET_BUFFER_SIZE;
72        setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf));
73        setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
74        // sine we don't use the "return channel", we keep it small...
75        setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
76        setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
77        fcntl(sockets[0], F_SETFL, O_NONBLOCK);
78        fcntl(sockets[1], F_SETFL, O_NONBLOCK);
79        mReceiveFd = sockets[0];
80        mSendFd = sockets[1];
81    } else {
82        mReceiveFd = -errno;
83        ALOGE("BitTube: pipe creation failed (%s)", strerror(-mReceiveFd));
84    }
85}
86
87status_t BitTube::initCheck() const
88{
89    if (mReceiveFd < 0) {
90        return status_t(mReceiveFd);
91    }
92    return NO_ERROR;
93}
94
95int BitTube::getFd() const
96{
97    return mReceiveFd;
98}
99
100int BitTube::getSendFd() const
101{
102    return mSendFd;
103}
104
105ssize_t BitTube::write(void const* vaddr, size_t size)
106{
107    ssize_t err, len;
108    do {
109        len = ::send(mSendFd, vaddr, size, MSG_DONTWAIT | MSG_NOSIGNAL);
110        // cannot return less than size, since we're using SOCK_SEQPACKET
111        err = len < 0 ? errno : 0;
112    } while (err == EINTR);
113    return err == 0 ? len : -err;
114}
115
116ssize_t BitTube::read(void* vaddr, size_t size)
117{
118    ssize_t err, len;
119    do {
120        len = ::recv(mReceiveFd, vaddr, size, MSG_DONTWAIT);
121        err = len < 0 ? errno : 0;
122    } while (err == EINTR);
123    if (err == EAGAIN || err == EWOULDBLOCK) {
124        // EAGAIN means that we have non-blocking I/O but there was
125        // no data to be read. Nothing the client should care about.
126        return 0;
127    }
128    return err == 0 ? len : -err;
129}
130
131status_t BitTube::writeToParcel(Parcel* reply) const
132{
133    if (mReceiveFd < 0)
134        return -EINVAL;
135
136    status_t result = reply->writeDupFileDescriptor(mReceiveFd);
137    close(mReceiveFd);
138    mReceiveFd = -1;
139    return result;
140}
141
142
143ssize_t BitTube::sendObjects(const sp<BitTube>& tube,
144        void const* events, size_t count, size_t objSize)
145{
146    const char* vaddr = reinterpret_cast<const char*>(events);
147    ssize_t size = tube->write(vaddr, count*objSize);
148
149    // should never happen because of SOCK_SEQPACKET
150    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
151            "BitTube::sendObjects(count=%zu, size=%zu), res=%zd (partial events were sent!)",
152            count, objSize, size);
153
154    //ALOGE_IF(size<0, "error %d sending %d events", size, count);
155    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
156}
157
158ssize_t BitTube::recvObjects(const sp<BitTube>& tube,
159        void* events, size_t count, size_t objSize)
160{
161    char* vaddr = reinterpret_cast<char*>(events);
162    ssize_t size = tube->read(vaddr, count*objSize);
163
164    // should never happen because of SOCK_SEQPACKET
165    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
166            "BitTube::recvObjects(count=%zu, size=%zu), res=%zd (partial events were received!)",
167            count, objSize, size);
168
169    //ALOGE_IF(size<0, "error %d receiving %d events", size, count);
170    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
171}
172
173// ----------------------------------------------------------------------------
174}; // namespace android
175