ipc unix domain socket

content/post/ipc-signal.md

@@ -2,6 +2,7 @@
 title: "Ipc Signal"
 date: 2023-04-11T20:15:57+08:00
 draft: false
+tags: ["ipc"]
 ---
 
 # signal

content/post/ipc-unix-domain-socket.md

@@ -0,0 +1,145 @@
+---
+title: "Ipc Unix Domain Socket"
+date: 2024-07-23T15:00:13+08:00
+draft: false
+tags: ["ipc"]
+---
+
+# unix domain socket 是啥?
+
+> A Unix domain socket (UDS) or IPC socket (inter-process communication) is a data communications endpoint for exchanging data between processes executing on the same host operating system. 
+> 同一台机器两个不同的进程之间交换数据，优化过的 socket。
+
+# 问题背景
+
+> java 写的程序需要和 c 写的程序交换数据，且两个程序运行在同一台机器上。
+
+# gradle 配置
+
+```groovy
+// https://mvnrepository.com/artifact/com.kohlschutter.junixsocket/junixsocket-native-common
+implementation group: 'com.kohlschutter.junixsocket', name: 'junixsocket-native-common', version: '2.9.1'
+
+// https://mvnrepository.com/artifact/com.kohlschutter.junixsocket/junixsocket-common
+implementation group: 'com.kohlschutter.junixsocket', name: 'junixsocket-common', version: '2.9.1'
+```
+
+# 程序示例
+
+```java
+import org.newsclub.net.unix.AFUNIXServerSocket;
+import org.newsclub.net.unix.AFUNIXSocket;
+import org.newsclub.net.unix.AFUNIXSocketAddress;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.*;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+
+/**
+ * unix domain socket 进程通信
+ */
+@SuppressWarnings({"CatchAndPrintStackTrace" /* errorprone */, "PMD.CognitiveComplexity"})
+public final class MsgServer implements Runnable {
+    private static final String UDS = System.getProperty("user.home") + "ipc.sock";
+    private static final Logger logger = LoggerFactory.getLogger(MsgServer.class);
+
+    private static void startServer() throws IOException {
+        Path path = Paths.get(UDS);
+        logger.info("UDO  path: {}", UDS);
+        if (Files.exists(path)) {
+            Files.delete(path);
+        }
+
+        File socketFile = new File(UDS);
+        try (AFUNIXServerSocket server = AFUNIXServerSocket.newInstance()) {
+            server.setReuseAddress(false);
+            server.bind(AFUNIXSocketAddress.of(socketFile));
+            logger.info("MsgServer 监听 socket: {}", server);
+
+            while (!Thread.interrupted() && !server.isClosed()) {
+                logger.info("Waiting for connection...");
+                try {
+                    AFUNIXSocket sock = server.accept();
+                    Thread thread = new Thread(new ClientHandler(sock), "msg-receiver");
+                    thread.start();
+                } catch (IOException e) {
+                    logger.error("server.accept() 出错", e);
+                }
+            }
+        } finally {
+            logger.info("MsgServer terminated");
+        }
+    }
+
+    @Override
+    public void run() {
+        try {
+            startServer();
+        } catch (IOException e) {
+            logger.error("启动 MsgServer 失败", e);
+        }
+    }
+
+    /**
+     * 处理连接,以接收 utf-8 字符串为例
+     */
+    static class ClientHandler implements Runnable {
+        AFUNIXSocket sock;
+
+        public ClientHandler(AFUNIXSocket socket) {
+            this.sock = socket;
+        }
+
+        @Override
+        public void run() {
+            try (InputStream is = sock.getInputStream(); OutputStream os = sock.getOutputStream(); PrintWriter writer = new PrintWriter(os, true); BufferedReader reader = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8))) {
+                String line;
+                while ((line = reader.readLine()) != null && !line.equalsIgnoreCase("bye")) {
+                    logger.info("Received: " + line);
+                    handleMsg(line);
+                    writer.println("Received successfully");
+                    writer.flush();
+                }
+            } catch (IOException e) {
+                logger.error("客户端关闭了连接", e);
+            } finally {
+                try {
+                    sock.close();
+                } catch (IOException e) {
+                    logger.error("关闭连接出错", e);
+                }
+            }
+
+        }
+
+        private void handleMsg(String msg) {
+            // process receive string msg
+        }
+
+    }
+
+}
+
+```
+
+
+
+
+
+
+
+
+
+
+
+
+# References
+
+1. [junixsocket](https://github.com/kohlschutter/junixsocket)
+2. [Unix_domain_socket](https://en.wikipedia.org/wiki/Unix_domain_socket)
+