| /* |
| * Copyright (c) 2005, 2014, 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 |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package sun.tools.attach; |
| |
| import com.sun.tools.attach.AttachOperationFailedException; |
| import com.sun.tools.attach.AgentLoadException; |
| import com.sun.tools.attach.AttachNotSupportedException; |
| import com.sun.tools.attach.spi.AttachProvider; |
| |
| import java.io.InputStream; |
| import java.io.IOException; |
| import java.io.File; |
| import java.io.FileNotFoundException; |
| |
| /* |
| * Solaris implementation of HotSpotVirtualMachine. |
| */ |
| public class VirtualMachineImpl extends HotSpotVirtualMachine { |
| // "/tmp" is used as a global well-known location for the files |
| // .java_pid<pid>. and .attach_pid<pid>. It is important that this |
| // location is the same for all processes, otherwise the tools |
| // will not be able to find all Hotspot processes. |
| // Any changes to this needs to be synchronized with HotSpot. |
| private static final String tmpdir = "/tmp"; |
| |
| // door descriptor; |
| private int fd = -1; |
| |
| /** |
| * Attaches to the target VM |
| */ |
| VirtualMachineImpl(AttachProvider provider, String vmid) |
| throws AttachNotSupportedException, IOException |
| { |
| super(provider, vmid); |
| // This provider only understands process-ids (pids). |
| int pid; |
| try { |
| pid = Integer.parseInt(vmid); |
| } catch (NumberFormatException x) { |
| throw new AttachNotSupportedException("invalid process identifier"); |
| } |
| |
| // Opens the door file to the target VM. If the file is not |
| // found it might mean that the attach mechanism isn't started in the |
| // target VM so we attempt to start it and retry. |
| try { |
| fd = openDoor(pid); |
| } catch (FileNotFoundException fnf1) { |
| File f = createAttachFile(pid); |
| try { |
| sigquit(pid); |
| |
| // give the target VM time to start the attach mechanism |
| final int delay_step = 100; |
| final long timeout = attachTimeout(); |
| long time_spend = 0; |
| long delay = 0; |
| do { |
| // Increase timeout on each attempt to reduce polling |
| delay += delay_step; |
| try { |
| Thread.sleep(delay); |
| } catch (InterruptedException x) { } |
| try { |
| fd = openDoor(pid); |
| } catch (FileNotFoundException fnf2) { |
| // pass |
| } |
| |
| time_spend += delay; |
| if (time_spend > timeout/2 && fd == -1) { |
| // Send QUIT again to give target VM the last chance to react |
| sigquit(pid); |
| } |
| } while (time_spend <= timeout && fd == -1); |
| if (fd == -1) { |
| throw new AttachNotSupportedException( |
| String.format("Unable to open door %s: " + |
| "target process %d doesn't respond within %dms " + |
| "or HotSpot VM not loaded", f.getPath(), pid, time_spend)); |
| } |
| } finally { |
| f.delete(); |
| } |
| } |
| assert fd >= 0; |
| } |
| |
| /** |
| * Detach from the target VM |
| */ |
| public void detach() throws IOException { |
| synchronized (this) { |
| if (fd != -1) { |
| close(fd); |
| fd = -1; |
| } |
| } |
| } |
| |
| /** |
| * Execute the given command in the target VM. |
| */ |
| InputStream execute(String cmd, Object ... args) throws AgentLoadException, IOException { |
| assert args.length <= 3; // includes null |
| |
| // first check that we are still attached |
| int door; |
| synchronized (this) { |
| if (fd == -1) { |
| throw new IOException("Detached from target VM"); |
| } |
| door = fd; |
| } |
| |
| // enqueue the command via a door call |
| int s = enqueue(door, cmd, args); |
| assert s >= 0; // valid file descriptor |
| |
| // The door call returns a file descriptor (one end of a socket pair). |
| // Create an input stream around it. |
| SocketInputStream sis = new SocketInputStream(s); |
| |
| // Read the command completion status |
| int completionStatus; |
| try { |
| completionStatus = readInt(sis); |
| } catch (IOException ioe) { |
| sis.close(); |
| throw ioe; |
| } |
| |
| // If non-0 it means an error but we need to special-case the |
| // "load" command to ensure that the right exception is thrown. |
| if (completionStatus != 0) { |
| // read from the stream and use that as the error message |
| String message = readErrorMessage(sis); |
| sis.close(); |
| if (cmd.equals("load")) { |
| String msg = "Failed to load agent library"; |
| if (!message.isEmpty()) |
| msg += ": " + message; |
| throw new AgentLoadException(msg); |
| } else { |
| if (message.isEmpty()) |
| message = "Command failed in target VM"; |
| throw new AttachOperationFailedException(message); |
| } |
| } |
| |
| // Return the input stream so that the command output can be read |
| return sis; |
| } |
| |
| // InputStream over a socket |
| private class SocketInputStream extends InputStream { |
| int s; |
| |
| public SocketInputStream(int s) { |
| this.s = s; |
| } |
| |
| public synchronized int read() throws IOException { |
| byte b[] = new byte[1]; |
| int n = this.read(b, 0, 1); |
| if (n == 1) { |
| return b[0] & 0xff; |
| } else { |
| return -1; |
| } |
| } |
| |
| public synchronized int read(byte[] bs, int off, int len) throws IOException { |
| if ((off < 0) || (off > bs.length) || (len < 0) || |
| ((off + len) > bs.length) || ((off + len) < 0)) { |
| throw new IndexOutOfBoundsException(); |
| } else if (len == 0) |
| return 0; |
| |
| return VirtualMachineImpl.read(s, bs, off, len); |
| } |
| |
| public void close() throws IOException { |
| VirtualMachineImpl.close(s); |
| } |
| } |
| |
| // The door is attached to .java_pid<pid> in the temporary directory. |
| private int openDoor(int pid) throws IOException { |
| String path = tmpdir + "/.java_pid" + pid;; |
| fd = open(path); |
| |
| // Check that the file owner/permission to avoid attaching to |
| // bogus process |
| try { |
| checkPermissions(path); |
| } catch (IOException ioe) { |
| close(fd); |
| throw ioe; |
| } |
| return fd; |
| } |
| |
| // On Solaris/Linux a simple handshake is used to start the attach mechanism |
| // if not already started. The client creates a .attach_pid<pid> file in the |
| // target VM's working directory (or temporary directory), and the SIGQUIT |
| // handler checks for the file. |
| private File createAttachFile(int pid) throws IOException { |
| String fn = ".attach_pid" + pid; |
| String path = "/proc/" + pid + "/cwd/" + fn; |
| File f = new File(path); |
| try { |
| f.createNewFile(); |
| } catch (IOException x) { |
| f = new File(tmpdir, fn); |
| f.createNewFile(); |
| } |
| return f; |
| } |
| |
| //-- native methods |
| |
| static native int open(String path) throws IOException; |
| |
| static native void close(int fd) throws IOException; |
| |
| static native int read(int fd, byte buf[], int off, int buflen) throws IOException; |
| |
| static native void checkPermissions(String path) throws IOException; |
| |
| static native void sigquit(int pid) throws IOException; |
| |
| // enqueue a command (and arguments) to the given door |
| static native int enqueue(int fd, String cmd, Object ... args) |
| throws IOException; |
| |
| static { |
| System.loadLibrary("attach"); |
| } |
| } |