1 /*
2 * Copyright (C) 2016 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 "UnixSocket.h"
18
19 #include <string.h>
20 #include <sys/socket.h>
21 #include <sys/un.h>
22 #include <unistd.h>
23
24 #include <algorithm>
25
26 #include <android-base/logging.h>
27
28 #include "IOEventLoop.h"
29
CreateUnixSocketAddress(const std::string & server_path,bool is_abstract,sockaddr_un & serv_addr)30 static bool CreateUnixSocketAddress(const std::string& server_path,
31 bool is_abstract, sockaddr_un& serv_addr) {
32 memset(&serv_addr, 0, sizeof(serv_addr));
33 serv_addr.sun_family = AF_UNIX;
34 size_t sun_path_len = sizeof(serv_addr.sun_path);
35 char* p = serv_addr.sun_path;
36 if (is_abstract) {
37 sun_path_len--;
38 p++;
39 }
40 if (server_path.size() + 1 > sun_path_len) {
41 LOG(ERROR) << "can't create unix domain socket as server path is too long: "
42 << server_path;
43 return false;
44 }
45 strcpy(p, server_path.c_str());
46 return true;
47 }
48
Create(const std::string & server_path,bool is_abstract)49 std::unique_ptr<UnixSocketServer> UnixSocketServer::Create(
50 const std::string& server_path, bool is_abstract) {
51 int sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
52 if (sockfd < 0) {
53 PLOG(ERROR) << "socket() failed";
54 return nullptr;
55 }
56 sockaddr_un serv_addr;
57 if (!CreateUnixSocketAddress(server_path, is_abstract, serv_addr)) {
58 return nullptr;
59 }
60 if (bind(sockfd, reinterpret_cast<sockaddr*>(&serv_addr), sizeof(serv_addr)) <
61 0) {
62 PLOG(ERROR) << "bind() failed for " << server_path;
63 return nullptr;
64 }
65 if (listen(sockfd, 1) < 0) {
66 PLOG(ERROR) << "listen() failed";
67 return nullptr;
68 }
69 return std::unique_ptr<UnixSocketServer>(
70 new UnixSocketServer(sockfd, server_path));
71 }
72
~UnixSocketServer()73 UnixSocketServer::~UnixSocketServer() { close(server_fd_); }
74
AcceptConnection()75 std::unique_ptr<UnixSocketConnection> UnixSocketServer::AcceptConnection() {
76 int sockfd = accept(server_fd_, nullptr, nullptr);
77 if (sockfd < 0) {
78 PLOG(ERROR) << "accept() failed";
79 return nullptr;
80 }
81 return std::unique_ptr<UnixSocketConnection>(
82 new UnixSocketConnection(sockfd));
83 }
84
Connect(const std::string & server_path,bool is_abstract)85 std::unique_ptr<UnixSocketConnection> UnixSocketConnection::Connect(
86 const std::string& server_path, bool is_abstract) {
87 int sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
88 if (sockfd < 0) {
89 PLOG(DEBUG) << "socket() failed";
90 return nullptr;
91 }
92 sockaddr_un serv_addr;
93 if (!CreateUnixSocketAddress(server_path, is_abstract, serv_addr)) {
94 return nullptr;
95 }
96 if (connect(sockfd, reinterpret_cast<sockaddr*>(&serv_addr),
97 sizeof(serv_addr)) < 0) {
98 PLOG(DEBUG) << "connect() failed, server_path = " << server_path;
99 return nullptr;
100 }
101 return std::unique_ptr<UnixSocketConnection>(
102 new UnixSocketConnection(sockfd));
103 }
104
PrepareForIO(IOEventLoop & loop,const std::function<bool (const UnixSocketMessage &)> & receive_message_callback,const std::function<bool ()> & close_connection_callback)105 bool UnixSocketConnection::PrepareForIO(
106 IOEventLoop& loop, const std::function<bool(const UnixSocketMessage&)>&
107 receive_message_callback,
108 const std::function<bool()>& close_connection_callback) {
109 read_callback_ = receive_message_callback;
110 close_callback_ = close_connection_callback;
111 read_event_ = loop.AddReadEvent(fd_, [&]() { return ReadData(); });
112 if (read_event_ == nullptr) {
113 return false;
114 }
115 std::lock_guard<std::mutex> lock(send_buffer_and_write_event_mtx_);
116 write_event_ = loop.AddWriteEvent(fd_, [&]() { return WriteData(); });
117 if (write_event_ == nullptr) {
118 return false;
119 }
120 return DisableWriteEventWithLock();
121 }
122
WriteData()123 bool UnixSocketConnection::WriteData() {
124 const char* write_data;
125 size_t write_data_size;
126 if (!GetDataFromSendBuffer(&write_data, &write_data_size)) {
127 return false;
128 }
129 if (write_data_size == 0u) {
130 return true;
131 }
132 // Use MSG_NOSIGNAL to prevent receiving SIGPIPE.
133 ssize_t result =
134 TEMP_FAILURE_RETRY(send(fd_, write_data, write_data_size, MSG_NOSIGNAL));
135 if (result >= 0) {
136 std::lock_guard<std::mutex> lock(send_buffer_and_write_event_mtx_);
137 send_buffer_.CommitData(result);
138 } else if (errno != EAGAIN) {
139 PLOG(ERROR) << "send() failed";
140 return false;
141 }
142 return true;
143 }
144
GetDataFromSendBuffer(const char ** pdata,size_t * pdata_size)145 bool UnixSocketConnection::GetDataFromSendBuffer(const char** pdata,
146 size_t* pdata_size) {
147 {
148 std::lock_guard<std::mutex> lock(send_buffer_and_write_event_mtx_);
149 *pdata_size = send_buffer_.PeekData(pdata);
150 if (*pdata_size != 0u) {
151 return true;
152 }
153 // The send buffer is empty. If we can receive more messages, just disable
154 // the write event temporarily, otherwise close the connection.
155 if (!no_more_message_) {
156 return DisableWriteEventWithLock();
157 }
158 }
159 return CloseConnection();
160 }
161
ReadData()162 bool UnixSocketConnection::ReadData() {
163 ssize_t result =
164 TEMP_FAILURE_RETRY(read(fd_, &read_buffer_[read_buffer_size_],
165 read_buffer_.size() - read_buffer_size_));
166 if (result < 0) {
167 if (errno == EAGAIN) {
168 return true;
169 }
170 PLOG(ERROR) << "read() failed";
171 return false;
172 } else if (result == 0) {
173 // The connection is closed, and no need to write pending messages.
174 return CloseConnection();
175 }
176 read_buffer_size_ += result;
177 return ConsumeDataInReadBuffer();
178 }
179
ConsumeDataInReadBuffer()180 bool UnixSocketConnection::ConsumeDataInReadBuffer() {
181 char* p = read_buffer_.data();
182 size_t left_size = read_buffer_size_;
183 uint32_t aligned_len = 0;
184 while (left_size >= sizeof(UnixSocketMessage)) {
185 UnixSocketMessage* msg = reinterpret_cast<UnixSocketMessage*>(p);
186 aligned_len = Align(msg->len, UnixSocketMessageAlignment);
187 if (left_size < aligned_len) {
188 break;
189 }
190 if (!read_callback_(*msg)) {
191 return false;
192 }
193 p += aligned_len;
194 left_size -= aligned_len;
195 }
196 if (left_size > 0u) {
197 // Move the unfinished message to the start of read_buffer_.
198 memmove(read_buffer_.data(), p, left_size);
199 // Extend the buffer to store this big message.
200 if (aligned_len > read_buffer_.size()) {
201 read_buffer_.resize(aligned_len);
202 }
203 }
204 read_buffer_size_ = left_size;
205 return true;
206 }
207
CloseConnection()208 bool UnixSocketConnection::CloseConnection() {
209 // Disable read_event and write_event here, so ReadData() and WriteData()
210 // won't be called in the future.
211 if (!IOEventLoop::DisableEvent(read_event_)) {
212 return false;
213 }
214 {
215 std::lock_guard<std::mutex> lock(send_buffer_and_write_event_mtx_);
216 no_more_message_ = true;
217 if (!DisableWriteEventWithLock()) {
218 return false;
219 }
220 }
221 close(fd_);
222 fd_ = -1;
223 return close_callback_();
224 }
225
~UnixSocketConnection()226 UnixSocketConnection::~UnixSocketConnection() {
227 if (fd_ != -1) {
228 // It only happens when IO operations are not finished properly by
229 // CloseConnection(). Don't call CloseConnection() here as the
230 // IOEventLoop used to register read/write events may have been destroyed.
231 close(fd_);
232 }
233 }
234