J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | package sun.tools.attach; |
| 26 | |
| 27 | import com.sun.tools.attach.VirtualMachine; |
| 28 | import com.sun.tools.attach.AgentLoadException; |
| 29 | import com.sun.tools.attach.AttachNotSupportedException; |
| 30 | import com.sun.tools.attach.spi.AttachProvider; |
| 31 | import java.io.InputStream; |
| 32 | import java.io.IOException; |
| 33 | import java.io.File; |
| 34 | import java.util.Properties; |
| 35 | |
| 36 | /* |
| 37 | * Linux implementation of HotSpotVirtualMachine |
| 38 | */ |
| 39 | public class LinuxVirtualMachine extends HotSpotVirtualMachine { |
| 40 | |
| 41 | // Indicates if this machine uses the old LinuxThreads |
| 42 | static boolean isLinuxThreads; |
| 43 | |
| 44 | // The patch to the socket file created by the target VM |
| 45 | String path; |
| 46 | |
| 47 | /** |
| 48 | * Attaches to the target VM |
| 49 | */ |
| 50 | LinuxVirtualMachine(AttachProvider provider, String vmid) |
| 51 | throws AttachNotSupportedException, IOException |
| 52 | { |
| 53 | super(provider, vmid); |
| 54 | |
| 55 | // This provider only understands pids |
| 56 | int pid; |
| 57 | try { |
| 58 | pid = Integer.parseInt(vmid); |
| 59 | } catch (NumberFormatException x) { |
| 60 | throw new AttachNotSupportedException("Invalid process identifier"); |
| 61 | } |
| 62 | |
| 63 | // Find the socket file. If not found then we attempt to start the |
| 64 | // attach mechanism in the target VM by sending it a QUIT signal. |
| 65 | // Then we attempt to find the socket file again. |
| 66 | path = findSocketFile(pid); |
| 67 | if (path == null) { |
| 68 | File f = createAttachFile(pid); |
| 69 | try { |
| 70 | // On LinuxThreads each thread is a process and we don't have the |
| 71 | // pid of the VMThread which has SIGQUIT unblocked. To workaround |
| 72 | // this we get the pid of the "manager thread" that is created |
| 73 | // by the first call to pthread_create. This is parent of all |
| 74 | // threads (except the initial thread). |
| 75 | if (isLinuxThreads) { |
| 76 | int mpid; |
| 77 | try { |
| 78 | mpid = getLinuxThreadsManager(pid); |
| 79 | } catch (IOException x) { |
| 80 | throw new AttachNotSupportedException(x.getMessage()); |
| 81 | } |
| 82 | assert(mpid >= 1); |
| 83 | sendQuitToChildrenOf(mpid); |
| 84 | } else { |
| 85 | sendQuitTo(pid); |
| 86 | } |
| 87 | |
| 88 | // give the target VM time to start the attach mechanism |
| 89 | int i = 0; |
| 90 | long delay = 200; |
| 91 | int retries = (int)(attachTimeout() / delay); |
| 92 | do { |
| 93 | try { |
| 94 | Thread.sleep(delay); |
| 95 | } catch (InterruptedException x) { } |
| 96 | path = findSocketFile(pid); |
| 97 | i++; |
| 98 | } while (i <= retries && path == null); |
| 99 | if (path == null) { |
| 100 | throw new AttachNotSupportedException( |
| 101 | "Unable to open socket file: target process not responding " + |
| 102 | "or HotSpot VM not loaded"); |
| 103 | } |
| 104 | } finally { |
| 105 | f.delete(); |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | // Check that the file owner/permission to avoid attaching to |
| 110 | // bogus process |
| 111 | checkPermissions(path); |
| 112 | |
| 113 | // Check that we can connect to the process |
| 114 | // - this ensures we throw the permission denied error now rather than |
| 115 | // later when we attempt to enqueue a command. |
| 116 | int s = socket(); |
| 117 | try { |
| 118 | connect(s, path); |
| 119 | } finally { |
| 120 | close(s); |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * Detach from the target VM |
| 126 | */ |
| 127 | public void detach() throws IOException { |
| 128 | synchronized (this) { |
| 129 | if (this.path != null) { |
| 130 | this.path = null; |
| 131 | } |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | // protocol version |
| 136 | private final static String PROTOCOL_VERSION = "1"; |
| 137 | |
| 138 | // known errors |
| 139 | private final static int ATTACH_ERROR_BADVERSION = 101; |
| 140 | |
| 141 | /** |
| 142 | * Execute the given command in the target VM. |
| 143 | */ |
| 144 | InputStream execute(String cmd, Object ... args) throws AgentLoadException, IOException { |
| 145 | assert args.length <= 3; // includes null |
| 146 | |
| 147 | // did we detach? |
| 148 | String p; |
| 149 | synchronized (this) { |
| 150 | if (this.path == null) { |
| 151 | throw new IOException("Detached from target VM"); |
| 152 | } |
| 153 | p = this.path; |
| 154 | } |
| 155 | |
| 156 | // create UNIX socket |
| 157 | int s = socket(); |
| 158 | |
| 159 | // connect to target VM |
| 160 | try { |
| 161 | connect(s, p); |
| 162 | } catch (IOException x) { |
| 163 | close(s); |
| 164 | throw x; |
| 165 | } |
| 166 | |
| 167 | IOException ioe = null; |
| 168 | |
| 169 | // connected - write request |
| 170 | // <ver> <cmd> <args...> |
| 171 | try { |
| 172 | writeString(s, PROTOCOL_VERSION); |
| 173 | writeString(s, cmd); |
| 174 | |
| 175 | for (int i=0; i<3; i++) { |
| 176 | if (i < args.length && args[i] != null) { |
| 177 | writeString(s, (String)args[i]); |
| 178 | } else { |
| 179 | writeString(s, ""); |
| 180 | } |
| 181 | } |
| 182 | } catch (IOException x) { |
| 183 | ioe = x; |
| 184 | } |
| 185 | |
| 186 | |
| 187 | // Create an input stream to read reply |
| 188 | SocketInputStream sis = new SocketInputStream(s); |
| 189 | |
| 190 | // Read the command completion status |
| 191 | int completionStatus; |
| 192 | try { |
| 193 | completionStatus = readInt(sis); |
| 194 | } catch (IOException x) { |
| 195 | sis.close(); |
| 196 | if (ioe != null) { |
| 197 | throw ioe; |
| 198 | } else { |
| 199 | throw x; |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | if (completionStatus != 0) { |
| 204 | sis.close(); |
| 205 | |
| 206 | // In the event of a protocol mismatch then the target VM |
| 207 | // returns a known error so that we can throw a reasonable |
| 208 | // error. |
| 209 | if (completionStatus == ATTACH_ERROR_BADVERSION) { |
| 210 | throw new IOException("Protocol mismatch with target VM"); |
| 211 | } |
| 212 | |
| 213 | // Special-case the "load" command so that the right exception is |
| 214 | // thrown. |
| 215 | if (cmd.equals("load")) { |
| 216 | throw new AgentLoadException("Failed to load agent library"); |
| 217 | } else { |
| 218 | throw new IOException("Command failed in target VM"); |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | // Return the input stream so that the command output can be read |
| 223 | return sis; |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | * InputStream for the socket connection to get target VM |
| 228 | */ |
| 229 | private class SocketInputStream extends InputStream { |
| 230 | int s; |
| 231 | |
| 232 | public SocketInputStream(int s) { |
| 233 | this.s = s; |
| 234 | } |
| 235 | |
| 236 | public synchronized int read() throws IOException { |
| 237 | byte b[] = new byte[1]; |
| 238 | int n = this.read(b, 0, 1); |
| 239 | if (n == 1) { |
| 240 | return b[0] & 0xff; |
| 241 | } else { |
| 242 | return -1; |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | public synchronized int read(byte[] bs, int off, int len) throws IOException { |
| 247 | if ((off < 0) || (off > bs.length) || (len < 0) || |
| 248 | ((off + len) > bs.length) || ((off + len) < 0)) { |
| 249 | throw new IndexOutOfBoundsException(); |
| 250 | } else if (len == 0) |
| 251 | return 0; |
| 252 | |
| 253 | return LinuxVirtualMachine.read(s, bs, off, len); |
| 254 | } |
| 255 | |
| 256 | public void close() throws IOException { |
| 257 | LinuxVirtualMachine.close(s); |
| 258 | } |
| 259 | } |
| 260 | |
| 261 | // Return the socket file for the given process. |
| 262 | // Checks working directory of process for .java_pid<pid>. If not |
| 263 | // found it looks in /tmp. |
| 264 | private String findSocketFile(int pid) { |
| 265 | // First check for a .java_pid<pid> file in the working directory |
| 266 | // of the target process |
| 267 | String fn = ".java_pid" + pid; |
| 268 | String path = "/proc/" + pid + "/cwd/" + fn; |
| 269 | File f = new File(path); |
| 270 | if (!f.exists()) { |
| 271 | // Not found, so try /tmp |
| 272 | path = "/tmp/" + fn; |
| 273 | f = new File(path); |
| 274 | if (!f.exists()) { |
| 275 | return null; // not found |
| 276 | } |
| 277 | } |
| 278 | return path; |
| 279 | } |
| 280 | |
| 281 | // On Solaris/Linux a simple handshake is used to start the attach mechanism |
| 282 | // if not already started. The client creates a .attach_pid<pid> file in the |
| 283 | // target VM's working directory (or /tmp), and the SIGQUIT handler checks |
| 284 | // for the file. |
| 285 | private File createAttachFile(int pid) throws IOException { |
| 286 | String fn = ".attach_pid" + pid; |
| 287 | String path = "/proc/" + pid + "/cwd/" + fn; |
| 288 | File f = new File(path); |
| 289 | try { |
| 290 | f.createNewFile(); |
| 291 | } catch (IOException x) { |
| 292 | path = "/tmp/" + fn; |
| 293 | f = new File(path); |
| 294 | f.createNewFile(); |
| 295 | } |
| 296 | return f; |
| 297 | } |
| 298 | |
| 299 | /* |
| 300 | * Write/sends the given to the target VM. String is transmitted in |
| 301 | * UTF-8 encoding. |
| 302 | */ |
| 303 | private void writeString(int fd, String s) throws IOException { |
| 304 | if (s.length() > 0) { |
| 305 | byte b[]; |
| 306 | try { |
| 307 | b = s.getBytes("UTF-8"); |
| 308 | } catch (java.io.UnsupportedEncodingException x) { |
| 309 | throw new InternalError(); |
| 310 | } |
| 311 | LinuxVirtualMachine.write(fd, b, 0, b.length); |
| 312 | } |
| 313 | byte b[] = new byte[1]; |
| 314 | b[0] = 0; |
| 315 | write(fd, b, 0, 1); |
| 316 | } |
| 317 | |
| 318 | |
| 319 | //-- native methods |
| 320 | |
| 321 | static native boolean isLinuxThreads(); |
| 322 | |
| 323 | static native int getLinuxThreadsManager(int pid) throws IOException; |
| 324 | |
| 325 | static native void sendQuitToChildrenOf(int pid) throws IOException; |
| 326 | |
| 327 | static native void sendQuitTo(int pid) throws IOException; |
| 328 | |
| 329 | static native void checkPermissions(String path) throws IOException; |
| 330 | |
| 331 | static native int socket() throws IOException; |
| 332 | |
| 333 | static native void connect(int fd, String path) throws IOException; |
| 334 | |
| 335 | static native void close(int fd) throws IOException; |
| 336 | |
| 337 | static native int read(int fd, byte buf[], int off, int bufLen) throws IOException; |
| 338 | |
| 339 | static native void write(int fd, byte buf[], int off, int bufLen) throws IOException; |
| 340 | |
| 341 | static { |
| 342 | System.loadLibrary("attach"); |
| 343 | isLinuxThreads = isLinuxThreads(); |
| 344 | } |
| 345 | } |