VirtualMachineImpl.java revision 10551:521ee1e45c45
111695Sache/* 211695Sache * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved. 311695Sache * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 411695Sache * 511695Sache * This code is free software; you can redistribute it and/or modify it 611695Sache * under the terms of the GNU General Public License version 2 only, as 711695Sache * published by the Free Software Foundation. Oracle designates this 8227753Stheraven * particular file as subject to the "Classpath" exception as provided 9227753Stheraven * by Oracle in the LICENSE file that accompanied this code. 10227753Stheraven * 11227753Stheraven * This code is distributed in the hope that it will be useful, but WITHOUT 12227753Stheraven * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1311695Sache * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1411695Sache * version 2 for more details (a copy is included in the LICENSE file that 1511695Sache * accompanied this code). 1611695Sache * 1711695Sache * You should have received a copy of the GNU General Public License version 1811695Sache * 2 along with this work; if not, write to the Free Software Foundation, 1911695Sache * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2011695Sache * 2111695Sache * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2211695Sache * or visit www.oracle.com if you need additional information or have any 2311695Sache * questions. 2411695Sache */ 2511695Sachepackage sun.tools.attach; 2611695Sache 2711695Sacheimport com.sun.tools.attach.AttachOperationFailedException; 2811695Sacheimport com.sun.tools.attach.AgentLoadException; 2911695Sacheimport com.sun.tools.attach.AttachNotSupportedException; 3011695Sacheimport com.sun.tools.attach.spi.AttachProvider; 3111695Sache 3211695Sacheimport java.io.InputStream; 3311695Sacheimport java.io.IOException; 3411695Sacheimport java.io.File; 3511695Sacheimport java.io.FileNotFoundException; 3611695Sache 3711695Sache/* 3892986Sobrien * Solaris implementation of HotSpotVirtualMachine. 3992986Sobrien */ 4092986Sobrienpublic class VirtualMachineImpl extends HotSpotVirtualMachine { 41150065Sstefanf // "/tmp" is used as a global well-known location for the files 423050Sache // .java_pid<pid>. and .attach_pid<pid>. It is important that this 43132820Stjr // location is the same for all processes, otherwise the tools 44227753Stheraven // will not be able to find all Hotspot processes. 45227753Stheraven // Any changes to this needs to be synchronized with HotSpot. 463050Sache private static final String tmpdir = "/tmp"; 47102227Smike 48227753Stheraven // door descriptor; 49102227Smike private int fd = -1; 50227753Stheraven 513050Sache /** 52129065Stjr * Attaches to the target VM 53227753Stheraven */ 54235239Sdim VirtualMachineImpl(AttachProvider provider, String vmid) 55129065Stjr throws AttachNotSupportedException, IOException 563050Sache { 5714812Sache super(provider, vmid); 5814812Sache // This provider only understands process-ids (pids). 5914812Sache int pid; 60129065Stjr try { 61130961Stjr pid = Integer.parseInt(vmid); 62130961Stjr } catch (NumberFormatException x) { 63129065Stjr throw new AttachNotSupportedException("invalid process identifier"); 64130961Stjr } 65227753Stheraven 66130961Stjr // Opens the door file to the target VM. If the file is not 67227753Stheraven // found it might mean that the attach mechanism isn't started in the 68130961Stjr // target VM so we attempt to start it and retry. 69129065Stjr try { 70129065Stjr fd = openDoor(pid); 71129065Stjr } catch (FileNotFoundException fnf1) { 723050Sache File f = createAttachFile(pid); 7361218Sache try { 743050Sache // kill -QUIT will tickle target VM to check for the 753050Sache // attach file. 76227753Stheraven sigquit(pid); 77227753Stheraven 78227753Stheraven // give the target VM time to start the attach mechanism 79227753Stheraven int i = 0; 80227753Stheraven long delay = 200; 81227753Stheraven int retries = (int)(attachTimeout() / delay); 82 do { 83 try { 84 Thread.sleep(delay); 85 } catch (InterruptedException x) { } 86 try { 87 fd = openDoor(pid); 88 } catch (FileNotFoundException fnf2) { } 89 i++; 90 } while (i <= retries && fd == -1); 91 if (fd == -1) { 92 throw new AttachNotSupportedException( 93 "Unable to open door: target process not responding or " + 94 "HotSpot VM not loaded"); 95 } 96 } finally { 97 f.delete(); 98 } 99 } 100 assert fd >= 0; 101 } 102 103 /** 104 * Detach from the target VM 105 */ 106 public void detach() throws IOException { 107 synchronized (this) { 108 if (fd != -1) { 109 close(fd); 110 fd = -1; 111 } 112 } 113 } 114 115 /** 116 * Execute the given command in the target VM. 117 */ 118 InputStream execute(String cmd, Object ... args) throws AgentLoadException, IOException { 119 assert args.length <= 3; // includes null 120 121 // first check that we are still attached 122 int door; 123 synchronized (this) { 124 if (fd == -1) { 125 throw new IOException("Detached from target VM"); 126 } 127 door = fd; 128 } 129 130 // enqueue the command via a door call 131 int s = enqueue(door, cmd, args); 132 assert s >= 0; // valid file descriptor 133 134 // The door call returns a file descriptor (one end of a socket pair). 135 // Create an input stream around it. 136 SocketInputStream sis = new SocketInputStream(s); 137 138 // Read the command completion status 139 int completionStatus; 140 try { 141 completionStatus = readInt(sis); 142 } catch (IOException ioe) { 143 sis.close(); 144 throw ioe; 145 } 146 147 // If non-0 it means an error but we need to special-case the 148 // "load" command to ensure that the right exception is thrown. 149 if (completionStatus != 0) { 150 // read from the stream and use that as the error message 151 String message = readErrorMessage(sis); 152 sis.close(); 153 if (cmd.equals("load")) { 154 throw new AgentLoadException("Failed to load agent library"); 155 } else { 156 if (message == null) { 157 throw new AttachOperationFailedException("Command failed in target VM"); 158 } else { 159 throw new AttachOperationFailedException(message); 160 } 161 } 162 } 163 164 // Return the input stream so that the command output can be read 165 return sis; 166 } 167 168 // InputStream over a socket 169 private class SocketInputStream extends InputStream { 170 int s; 171 172 public SocketInputStream(int s) { 173 this.s = s; 174 } 175 176 public synchronized int read() throws IOException { 177 byte b[] = new byte[1]; 178 int n = this.read(b, 0, 1); 179 if (n == 1) { 180 return b[0] & 0xff; 181 } else { 182 return -1; 183 } 184 } 185 186 public synchronized int read(byte[] bs, int off, int len) throws IOException { 187 if ((off < 0) || (off > bs.length) || (len < 0) || 188 ((off + len) > bs.length) || ((off + len) < 0)) { 189 throw new IndexOutOfBoundsException(); 190 } else if (len == 0) 191 return 0; 192 193 return VirtualMachineImpl.read(s, bs, off, len); 194 } 195 196 public void close() throws IOException { 197 VirtualMachineImpl.close(s); 198 } 199 } 200 201 // The door is attached to .java_pid<pid> in the temporary directory. 202 private int openDoor(int pid) throws IOException { 203 String path = tmpdir + "/.java_pid" + pid;; 204 fd = open(path); 205 206 // Check that the file owner/permission to avoid attaching to 207 // bogus process 208 try { 209 checkPermissions(path); 210 } catch (IOException ioe) { 211 close(fd); 212 throw ioe; 213 } 214 return fd; 215 } 216 217 // On Solaris/Linux a simple handshake is used to start the attach mechanism 218 // if not already started. The client creates a .attach_pid<pid> file in the 219 // target VM's working directory (or temporary directory), and the SIGQUIT 220 // handler checks for the file. 221 private File createAttachFile(int pid) throws IOException { 222 String fn = ".attach_pid" + pid; 223 String path = "/proc/" + pid + "/cwd/" + fn; 224 File f = new File(path); 225 try { 226 f.createNewFile(); 227 } catch (IOException x) { 228 f = new File(tmpdir, fn); 229 f.createNewFile(); 230 } 231 return f; 232 } 233 234 //-- native methods 235 236 static native int open(String path) throws IOException; 237 238 static native void close(int fd) throws IOException; 239 240 static native int read(int fd, byte buf[], int off, int buflen) throws IOException; 241 242 static native void checkPermissions(String path) throws IOException; 243 244 static native void sigquit(int pid) throws IOException; 245 246 // enqueue a command (and arguments) to the given door 247 static native int enqueue(int fd, String cmd, Object ... args) 248 throws IOException; 249 250 static { 251 System.loadLibrary("attach"); 252 } 253} 254