1 /* Copyright (c) 2017-2018 The Linux Foundation. All rights reserved.
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3  * Redistribution and use in source and binary forms, with or without
4  * modification, are permitted provided that the following conditions are
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8  *     * Redistributions in binary form must reproduce the above
9  *       copyright notice, this list of conditions and the following
10  *       disclaimer in the documentation and/or other materials provided
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29 
30 #ifndef __LOC_SOCKET__
31 #define __LOC_SOCKET__
32 
33 #include <string>
34 #include <memory>
35 #include <unistd.h>
36 #include <sys/socket.h>
37 #include <sys/un.h>
38 #include <LocThread.h>
39 
40 namespace loc_util {
41 
42 class LocIpcSender;
43 
44 class LocIpc {
45 friend LocIpcSender;
46 public:
LocIpc()47     inline LocIpc() : mIpcFd(-1), mStopRequested(false), mRunnable(nullptr) {}
~LocIpc()48     inline virtual ~LocIpc() { stopListening(); }
49 
50     // Listen for new messages in current thread. Calling this funciton will
51     // block current thread. The listening can be stopped by calling stopListening().
52     //
53     // Argument name is the path of the unix local socket to be listened.
54     // The function will return true on success, and false on failure.
55     bool startListeningBlocking(const std::string& name);
56 
57     // Create a new LocThread and listen for new messages in it.
58     // Calling this function will return immediately and won't block current thread.
59     // The listening can be stopped by calling stopListening().
60     //
61     // Argument name is the path of the unix local socket to be be listened.
62     // The function will return true on success, and false on failure.
63     bool startListeningNonBlocking(const std::string& name);
64 
65     // Stop listening to new messages.
66     void stopListening();
67 
68     // Send out a message.
69     // Call this function to send a message in argument data to socket in argument name.
70     //
71     // Argument name contains the name of the target unix socket. data contains the
72     // message to be sent out. Convert your message to a string before calling this function.
73     // The function will return true on success, and false on failure.
74     static bool send(const char name[], const std::string& data);
75     static bool send(const char name[], const uint8_t data[], uint32_t length);
76 
77 protected:
78     // Callback function for receiving incoming messages.
79     // Override this function in your derived class to process incoming messages.
80     // For each received message, this callback function will be called once.
81     // This callback function will be called in the calling thread of startListeningBlocking
82     // or in the new LocThread created by startListeningNonBlocking.
83     //
84     // Argument data contains the received message. You need to parse it.
onReceive(const std::string &)85     inline virtual void onReceive(const std::string& /*data*/) {}
86 
87     // LocIpc client can overwrite this function to get notification
88     // when the socket for LocIpc is ready to receive messages.
onListenerReady()89     inline virtual void onListenerReady() {}
90 
91 private:
92     static bool sendData(int fd, const sockaddr_un& addr,
93             const uint8_t data[], uint32_t length);
94 
95     int mIpcFd;
96     bool mStopRequested;
97     LocThread mThread;
98     LocRunnable *mRunnable;
99 };
100 
101 class LocIpcSender {
102 public:
103     // Constructor of LocIpcSender class
104     //
105     // Argument destSocket contains the full path name of destination socket.
106     // This class hides generated fd and destination address object from user.
LocIpcSender(const char * destSocket)107     inline LocIpcSender(const char* destSocket):
108             LocIpcSender(std::make_shared<int>(::socket(AF_UNIX, SOCK_DGRAM, 0)), destSocket) {
109         if (-1 == *mSocket) {
110             mSocket = nullptr;
111         }
112     }
113 
114     // Replicate a new LocIpcSender object with new destination socket.
replicate(const char * destSocket)115     inline LocIpcSender* replicate(const char* destSocket) {
116         return (nullptr == mSocket) ? nullptr : new LocIpcSender(mSocket, destSocket);
117     }
118 
~LocIpcSender()119     inline ~LocIpcSender() {
120         if (nullptr != mSocket && mSocket.unique()) {
121             ::close(*mSocket);
122         }
123     }
124 
125     // Send out a message.
126     // Call this function to send a message
127     //
128     // Argument data and length contains the message to be sent out.
129     // Return true when succeeded
send(const uint8_t data[],uint32_t length)130     inline bool send(const uint8_t data[], uint32_t length) {
131         bool rtv = false;
132         if (nullptr != mSocket && nullptr != data) {
133             rtv = LocIpc::sendData(*mSocket, mDestAddr, data, length);
134         }
135         return rtv;
136     }
137 
138 private:
139     std::shared_ptr<int> mSocket;
140     struct sockaddr_un mDestAddr;
141 
LocIpcSender(const std::shared_ptr<int> & mySocket,const char * destSocket)142     inline LocIpcSender(const std::shared_ptr<int>& mySocket, const char* destSocket) :
143         mSocket(mySocket),
144         mDestAddr({.sun_family = AF_UNIX, {}}) {
145         if ((nullptr != mSocket) && (-1 != *mSocket) && (nullptr != destSocket)) {
146             snprintf(mDestAddr.sun_path, sizeof(mDestAddr.sun_path), "%s", destSocket);
147         }
148     }
149 };
150 
151 }
152 
153 #endif //__LOC_SOCKET__
154