fix arthas-boot blocking in findTcpListenProcess method. #3007

Author: hengyunabc

common/src/main/java/com/taobao/arthas/common/SocketUtils.java

@@ -4,6 +4,12 @@
 import java.net.ServerSocket;
 import java.util.List;
 import java.util.Random;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 import javax.net.ServerSocketFactory;
 
@@ -32,33 +38,71 @@ private SocketUtils() {
     }
 
     public static long findTcpListenProcess(int port) {
+        // Add a timeout of 5 seconds to prevent blocking
+        final int TIMEOUT_SECONDS = 5;
+        ExecutorService executor = Executors.newSingleThreadExecutor();
         try {
-            if (OSUtils.isWindows()) {
-                String[] command = { "netstat", "-ano", "-p", "TCP" };
-                List<String> lines = ExecutingCommand.runNative(command);
-                for (String line : lines) {
-                    if (line.contains("LISTENING")) {
-                        // TCP 0.0.0.0:49168 0.0.0.0:0 LISTENING 476
-                        String[] strings = line.trim().split("\\s+");
-                        if (strings.length == 5) {
-                            if (strings[1].endsWith(":" + port)) {
-                                return Long.parseLong(strings[4]);
-                            }
-                        }
-                    }
+            Future<Long> future = executor.submit(new Callable<Long>() {
+                @Override
+                public Long call() throws Exception {
+                    return doFindTcpListenProcess(port);
                 }
+            });
+
+            try {
+                return future.get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
+            } catch (TimeoutException e) {
+                future.cancel(true);
+                return -1;
+            } catch (Exception e) {
+                return -1;
+            }
+        } finally {
+            executor.shutdownNow();
+        }
+    }
+
+    private static long doFindTcpListenProcess(int port) {
+        try {
+            if (OSUtils.isWindows()) {
+                return findTcpListenProcessOnWindows(port);
             }
 
             if (OSUtils.isLinux() || OSUtils.isMac()) {
-                String pid = ExecutingCommand.getFirstAnswer("lsof -t -s TCP:LISTEN -i TCP:" + port);
-                if (!pid.trim().isEmpty()) {
-                    return Long.parseLong(pid);
-                }
+                return findTcpListenProcessOnUnix(port);
             }
         } catch (Throwable e) {
             // ignore
         }
+        return -1;
+    }
+
+    private static long findTcpListenProcessOnWindows(int port) {
+        String[] command = { "netstat", "-ano", "-p", "TCP" };
+        List<String> lines = ExecutingCommand.runNative(command);
+        for (String line : lines) {
+            if (line.contains("LISTENING")) {
+                // TCP 0.0.0.0:49168 0.0.0.0:0 LISTENING 476
+                String[] strings = line.trim().split("\\s+");
+                if (strings.length == 5) {
+                    if (strings[1].endsWith(":" + port)) {
+                        return Long.parseLong(strings[4]);
+                    }
+                }
+            }
+        }
+        return -1;
+    }
 
+    private static long findTcpListenProcessOnUnix(int port) {
+        String pid = ExecutingCommand.getFirstAnswer("lsof -t -s TCP:LISTEN -i TCP:" + port);
+        if (pid != null && !pid.trim().isEmpty()) {
+            try {
+                return Long.parseLong(pid.trim());
+            } catch (NumberFormatException e) {
+                // ignore
+            }
+        }
         return -1;
     }