8342996: Enhance Attach API to support arbitrary length arguments - OSX

Reviewed-by: sspitsyn, kevinw

Author: Alex Menkov

src/jdk.attach/macosx/classes/sun/tools/attach/VirtualMachineImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,6 +48,7 @@ public class VirtualMachineImpl extends HotSpotVirtualMachine {
     // Any changes to this needs to be synchronized with HotSpot.
     private static final String tmpdir;
     String socket_path;
+    private int ver = VERSION_1;        // updated in ctor depending on detectVersion result
 
     /**
      * Attaches to the target VM
@@ -107,14 +108,18 @@ public class VirtualMachineImpl extends HotSpotVirtualMachine {
         // bogus process
         checkPermissions(socket_path);
 
-        // Check that we can connect to the process
-        // - this ensures we throw the permission denied error now rather than
-        // later when we attempt to enqueue a command.
-        int s = socket();
-        try {
-            connect(s, socket_path);
-        } finally {
-            close(s);
+        if (isAPIv2Enabled()) {
+            ver = detectVersion();
+        } else {
+            // Check that we can connect to the process
+            // - this ensures we throw the permission denied error now rather than
+            // later when we attempt to enqueue a command.
+            int s = socket();
+            try {
+                connect(s, socket_path);
+            } finally {
+                close(s);
+            }
         }
     }
 
@@ -129,14 +134,10 @@ public void detach() throws IOException {
         }
     }
 
-    // protocol version
-    private static final String PROTOCOL_VERSION = "1";
-
     /**
      * Execute the given command in the target VM.
      */
     InputStream execute(String cmd, Object ... args) throws AgentLoadException, IOException {
-        assert args.length <= 3;                // includes null
         checkNulls(args);
 
         // did we detach?
@@ -162,16 +163,8 @@ InputStream execute(String cmd, Object ... args) throws AgentLoadException, IOEx
         // connected - write request
         // <ver> <cmd> <args...>
         try {
-            writeString(s, PROTOCOL_VERSION);
-            writeString(s, cmd);
-
-            for (int i = 0; i < 3; i++) {
-                if (i < args.length && args[i] != null) {
-                    writeString(s, (String)args[i]);
-                } else {
-                    writeString(s, "");
-                }
-            }
+            SocketOutputStream writer = new SocketOutputStream(s);
+            writeCommand(writer, ver, cmd, args);
         } catch (IOException x) {
             ioe = x;
         }
@@ -187,6 +180,16 @@ InputStream execute(String cmd, Object ... args) throws AgentLoadException, IOEx
         return sis;
     }
 
+    private static class SocketOutputStream implements AttachOutputStream {
+        private int fd;
+        public SocketOutputStream(int fd) {
+            this.fd = fd;
+        }
+        @Override
+        public void write(byte[] buffer, int offset, int length) throws IOException {
+            VirtualMachineImpl.write(fd, buffer, offset, length);
+        }
+    }
     /*
      * InputStream for the socket connection to get target VM
      */
@@ -206,20 +209,6 @@ protected void close(long fd) throws IOException {
         }
     }
 
-    /*
-     * Write/sends the given to the target VM. String is transmitted in
-     * UTF-8 encoding.
-     */
-    private void writeString(int fd, String s) throws IOException {
-        if (s.length() > 0) {
-            byte[] b = s.getBytes(UTF_8);
-            VirtualMachineImpl.write(fd, b, 0, b.length);
-        }
-        byte b[] = new byte[1];
-        b[0] = 0;
-        write(fd, b, 0, 1);
-    }
-
     private File createAttachFile(int pid) throws IOException {
         File f = new File(tmpdir, ".attach_pid" + pid);
         createAttachFile0(f.getPath());