ZygoteInit.java revision 42a4bb5730266f80585e67262c73505d0bfffbf8
1/* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package com.android.internal.os; 18 19import static libcore.io.OsConstants.S_IRWXG; 20import static libcore.io.OsConstants.S_IRWXO; 21 22import android.content.res.Resources; 23import android.content.res.TypedArray; 24import android.net.LocalServerSocket; 25import android.os.Debug; 26import android.os.Process; 27import android.os.SystemClock; 28import android.os.Trace; 29import android.util.EventLog; 30import android.util.Log; 31 32import dalvik.system.VMRuntime; 33import dalvik.system.Zygote; 34 35import libcore.io.IoUtils; 36import libcore.io.Libcore; 37import libcore.io.OsConstants; 38 39import java.io.BufferedReader; 40import java.io.FileDescriptor; 41import java.io.IOException; 42import java.io.InputStream; 43import java.io.InputStreamReader; 44import java.lang.reflect.InvocationTargetException; 45import java.lang.reflect.Method; 46import java.lang.reflect.Modifier; 47import java.util.ArrayList; 48 49/** 50 * Startup class for the zygote process. 51 * 52 * Pre-initializes some classes, and then waits for commands on a UNIX domain 53 * socket. Based on these commands, forks off child processes that inherit 54 * the initial state of the VM. 55 * 56 * Please see {@link ZygoteConnection.Arguments} for documentation on the 57 * client protocol. 58 * 59 * @hide 60 */ 61public class ZygoteInit { 62 63 private static final String TAG = "Zygote"; 64 65 private static final String ANDROID_SOCKET_ENV = "ANDROID_SOCKET_zygote"; 66 67 private static final int LOG_BOOT_PROGRESS_PRELOAD_START = 3020; 68 private static final int LOG_BOOT_PROGRESS_PRELOAD_END = 3030; 69 70 /** when preloading, GC after allocating this many bytes */ 71 private static final int PRELOAD_GC_THRESHOLD = 50000; 72 73 public static final String USAGE_STRING = 74 " <\"start-system-server\"|\"\" for startSystemServer>"; 75 76 private static LocalServerSocket sServerSocket; 77 78 /** 79 * Used to pre-load resources. We hold a global reference on it so it 80 * never gets destroyed. 81 */ 82 private static Resources mResources; 83 84 /** 85 * The number of times that the main Zygote loop 86 * should run before calling gc() again. 87 */ 88 static final int GC_LOOP_COUNT = 10; 89 90 /** 91 * The name of a resource file that contains classes to preload. 92 */ 93 private static final String PRELOADED_CLASSES = "preloaded-classes"; 94 95 /** Controls whether we should preload resources during zygote init. */ 96 private static final boolean PRELOAD_RESOURCES = true; 97 98 /** 99 * Invokes a static "main(argv[]) method on class "className". 100 * Converts various failing exceptions into RuntimeExceptions, with 101 * the assumption that they will then cause the VM instance to exit. 102 * 103 * @param loader class loader to use 104 * @param className Fully-qualified class name 105 * @param argv Argument vector for main() 106 */ 107 static void invokeStaticMain(ClassLoader loader, 108 String className, String[] argv) 109 throws ZygoteInit.MethodAndArgsCaller { 110 Class<?> cl; 111 112 try { 113 cl = loader.loadClass(className); 114 } catch (ClassNotFoundException ex) { 115 throw new RuntimeException( 116 "Missing class when invoking static main " + className, 117 ex); 118 } 119 120 Method m; 121 try { 122 m = cl.getMethod("main", new Class[] { String[].class }); 123 } catch (NoSuchMethodException ex) { 124 throw new RuntimeException( 125 "Missing static main on " + className, ex); 126 } catch (SecurityException ex) { 127 throw new RuntimeException( 128 "Problem getting static main on " + className, ex); 129 } 130 131 int modifiers = m.getModifiers(); 132 if (! (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers))) { 133 throw new RuntimeException( 134 "Main method is not public and static on " + className); 135 } 136 137 /* 138 * This throw gets caught in ZygoteInit.main(), which responds 139 * by invoking the exception's run() method. This arrangement 140 * clears up all the stack frames that were required in setting 141 * up the process. 142 */ 143 throw new ZygoteInit.MethodAndArgsCaller(m, argv); 144 } 145 146 /** 147 * Registers a server socket for zygote command connections 148 * 149 * @throws RuntimeException when open fails 150 */ 151 private static void registerZygoteSocket() { 152 if (sServerSocket == null) { 153 int fileDesc; 154 try { 155 String env = System.getenv(ANDROID_SOCKET_ENV); 156 fileDesc = Integer.parseInt(env); 157 } catch (RuntimeException ex) { 158 throw new RuntimeException( 159 ANDROID_SOCKET_ENV + " unset or invalid", ex); 160 } 161 162 try { 163 sServerSocket = new LocalServerSocket( 164 createFileDescriptor(fileDesc)); 165 } catch (IOException ex) { 166 throw new RuntimeException( 167 "Error binding to local socket '" + fileDesc + "'", ex); 168 } 169 } 170 } 171 172 /** 173 * Waits for and accepts a single command connection. Throws 174 * RuntimeException on failure. 175 */ 176 private static ZygoteConnection acceptCommandPeer() { 177 try { 178 return new ZygoteConnection(sServerSocket.accept()); 179 } catch (IOException ex) { 180 throw new RuntimeException( 181 "IOException during accept()", ex); 182 } 183 } 184 185 /** 186 * Close and clean up zygote sockets. Called on shutdown and on the 187 * child's exit path. 188 */ 189 static void closeServerSocket() { 190 try { 191 if (sServerSocket != null) { 192 sServerSocket.close(); 193 } 194 } catch (IOException ex) { 195 Log.e(TAG, "Zygote: error closing sockets", ex); 196 } 197 198 sServerSocket = null; 199 } 200 201 private static final int UNPRIVILEGED_UID = 9999; 202 private static final int UNPRIVILEGED_GID = 9999; 203 204 private static final int ROOT_UID = 0; 205 private static final int ROOT_GID = 0; 206 207 /** 208 * Sets effective user ID. 209 */ 210 private static void setEffectiveUser(int uid) { 211 int errno = setreuid(ROOT_UID, uid); 212 if (errno != 0) { 213 Log.e(TAG, "setreuid() failed. errno: " + errno); 214 } 215 } 216 217 /** 218 * Sets effective group ID. 219 */ 220 private static void setEffectiveGroup(int gid) { 221 int errno = setregid(ROOT_GID, gid); 222 if (errno != 0) { 223 Log.e(TAG, "setregid() failed. errno: " + errno); 224 } 225 } 226 227 static void preload() { 228 preloadClasses(); 229 preloadResources(); 230 } 231 232 /** 233 * Performs Zygote process initialization. Loads and initializes 234 * commonly used classes. 235 * 236 * Most classes only cause a few hundred bytes to be allocated, but 237 * a few will allocate a dozen Kbytes (in one case, 500+K). 238 */ 239 private static void preloadClasses() { 240 final VMRuntime runtime = VMRuntime.getRuntime(); 241 242 InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream( 243 PRELOADED_CLASSES); 244 if (is == null) { 245 Log.e(TAG, "Couldn't find " + PRELOADED_CLASSES + "."); 246 } else { 247 Log.i(TAG, "Preloading classes..."); 248 long startTime = SystemClock.uptimeMillis(); 249 250 // Drop root perms while running static initializers. 251 setEffectiveGroup(UNPRIVILEGED_GID); 252 setEffectiveUser(UNPRIVILEGED_UID); 253 254 // Alter the target heap utilization. With explicit GCs this 255 // is not likely to have any effect. 256 float defaultUtilization = runtime.getTargetHeapUtilization(); 257 runtime.setTargetHeapUtilization(0.8f); 258 259 // Start with a clean slate. 260 System.gc(); 261 runtime.runFinalizationSync(); 262 Debug.startAllocCounting(); 263 264 try { 265 BufferedReader br 266 = new BufferedReader(new InputStreamReader(is), 256); 267 268 int count = 0; 269 String line; 270 while ((line = br.readLine()) != null) { 271 // Skip comments and blank lines. 272 line = line.trim(); 273 if (line.startsWith("#") || line.equals("")) { 274 continue; 275 } 276 277 try { 278 if (false) { 279 Log.v(TAG, "Preloading " + line + "..."); 280 } 281 Class.forName(line); 282 if (Debug.getGlobalAllocSize() > PRELOAD_GC_THRESHOLD) { 283 if (false) { 284 Log.v(TAG, 285 " GC at " + Debug.getGlobalAllocSize()); 286 } 287 System.gc(); 288 runtime.runFinalizationSync(); 289 Debug.resetGlobalAllocSize(); 290 } 291 count++; 292 } catch (ClassNotFoundException e) { 293 Log.w(TAG, "Class not found for preloading: " + line); 294 } catch (UnsatisfiedLinkError e) { 295 Log.w(TAG, "Problem preloading " + line + ": " + e); 296 } catch (Throwable t) { 297 Log.e(TAG, "Error preloading " + line + ".", t); 298 if (t instanceof Error) { 299 throw (Error) t; 300 } 301 if (t instanceof RuntimeException) { 302 throw (RuntimeException) t; 303 } 304 throw new RuntimeException(t); 305 } 306 } 307 308 Log.i(TAG, "...preloaded " + count + " classes in " 309 + (SystemClock.uptimeMillis()-startTime) + "ms."); 310 } catch (IOException e) { 311 Log.e(TAG, "Error reading " + PRELOADED_CLASSES + ".", e); 312 } finally { 313 IoUtils.closeQuietly(is); 314 // Restore default. 315 runtime.setTargetHeapUtilization(defaultUtilization); 316 317 Debug.stopAllocCounting(); 318 319 // Bring back root. We'll need it later. 320 setEffectiveUser(ROOT_UID); 321 setEffectiveGroup(ROOT_GID); 322 } 323 } 324 } 325 326 /** 327 * Load in commonly used resources, so they can be shared across 328 * processes. 329 * 330 * These tend to be a few Kbytes, but are frequently in the 20-40K 331 * range, and occasionally even larger. 332 */ 333 private static void preloadResources() { 334 final VMRuntime runtime = VMRuntime.getRuntime(); 335 336 Debug.startAllocCounting(); 337 try { 338 System.gc(); 339 runtime.runFinalizationSync(); 340 mResources = Resources.getSystem(); 341 mResources.startPreloading(); 342 if (PRELOAD_RESOURCES) { 343 Log.i(TAG, "Preloading resources..."); 344 345 long startTime = SystemClock.uptimeMillis(); 346 TypedArray ar = mResources.obtainTypedArray( 347 com.android.internal.R.array.preloaded_drawables); 348 int N = preloadDrawables(runtime, ar); 349 ar.recycle(); 350 Log.i(TAG, "...preloaded " + N + " resources in " 351 + (SystemClock.uptimeMillis()-startTime) + "ms."); 352 353 startTime = SystemClock.uptimeMillis(); 354 ar = mResources.obtainTypedArray( 355 com.android.internal.R.array.preloaded_color_state_lists); 356 N = preloadColorStateLists(runtime, ar); 357 ar.recycle(); 358 Log.i(TAG, "...preloaded " + N + " resources in " 359 + (SystemClock.uptimeMillis()-startTime) + "ms."); 360 } 361 mResources.finishPreloading(); 362 } catch (RuntimeException e) { 363 Log.w(TAG, "Failure preloading resources", e); 364 } finally { 365 Debug.stopAllocCounting(); 366 } 367 } 368 369 private static int preloadColorStateLists(VMRuntime runtime, TypedArray ar) { 370 int N = ar.length(); 371 for (int i=0; i<N; i++) { 372 if (Debug.getGlobalAllocSize() > PRELOAD_GC_THRESHOLD) { 373 if (false) { 374 Log.v(TAG, " GC at " + Debug.getGlobalAllocSize()); 375 } 376 System.gc(); 377 runtime.runFinalizationSync(); 378 Debug.resetGlobalAllocSize(); 379 } 380 int id = ar.getResourceId(i, 0); 381 if (false) { 382 Log.v(TAG, "Preloading resource #" + Integer.toHexString(id)); 383 } 384 if (id != 0) { 385 if (mResources.getColorStateList(id) == null) { 386 throw new IllegalArgumentException( 387 "Unable to find preloaded color resource #0x" 388 + Integer.toHexString(id) 389 + " (" + ar.getString(i) + ")"); 390 } 391 } 392 } 393 return N; 394 } 395 396 397 private static int preloadDrawables(VMRuntime runtime, TypedArray ar) { 398 int N = ar.length(); 399 for (int i=0; i<N; i++) { 400 if (Debug.getGlobalAllocSize() > PRELOAD_GC_THRESHOLD) { 401 if (false) { 402 Log.v(TAG, " GC at " + Debug.getGlobalAllocSize()); 403 } 404 System.gc(); 405 runtime.runFinalizationSync(); 406 Debug.resetGlobalAllocSize(); 407 } 408 int id = ar.getResourceId(i, 0); 409 if (false) { 410 Log.v(TAG, "Preloading resource #" + Integer.toHexString(id)); 411 } 412 if (id != 0) { 413 if (mResources.getDrawable(id) == null) { 414 throw new IllegalArgumentException( 415 "Unable to find preloaded drawable resource #0x" 416 + Integer.toHexString(id) 417 + " (" + ar.getString(i) + ")"); 418 } 419 } 420 } 421 return N; 422 } 423 424 /** 425 * Runs several special GCs to try to clean up a few generations of 426 * softly- and final-reachable objects, along with any other garbage. 427 * This is only useful just before a fork(). 428 */ 429 /*package*/ static void gc() { 430 final VMRuntime runtime = VMRuntime.getRuntime(); 431 432 /* runFinalizationSync() lets finalizers be called in Zygote, 433 * which doesn't have a HeapWorker thread. 434 */ 435 System.gc(); 436 runtime.runFinalizationSync(); 437 System.gc(); 438 runtime.runFinalizationSync(); 439 System.gc(); 440 runtime.runFinalizationSync(); 441 } 442 443 /** 444 * Finish remaining work for the newly forked system server process. 445 */ 446 private static void handleSystemServerProcess( 447 ZygoteConnection.Arguments parsedArgs) 448 throws ZygoteInit.MethodAndArgsCaller { 449 450 closeServerSocket(); 451 452 // set umask to 0077 so new files and directories will default to owner-only permissions. 453 Libcore.os.umask(S_IRWXG | S_IRWXO); 454 455 if (parsedArgs.niceName != null) { 456 Process.setArgV0(parsedArgs.niceName); 457 } 458 459 if (parsedArgs.invokeWith != null) { 460 WrapperInit.execApplication(parsedArgs.invokeWith, 461 parsedArgs.niceName, parsedArgs.targetSdkVersion, 462 null, parsedArgs.remainingArgs); 463 } else { 464 /* 465 * Pass the remaining arguments to SystemServer. 466 */ 467 RuntimeInit.zygoteInit(parsedArgs.targetSdkVersion, parsedArgs.remainingArgs); 468 } 469 470 /* should never reach here */ 471 } 472 473 /** 474 * Prepare the arguments and fork for the system server process. 475 */ 476 private static boolean startSystemServer() 477 throws MethodAndArgsCaller, RuntimeException { 478 long capabilities = posixCapabilitiesAsBits( 479 OsConstants.CAP_KILL, 480 OsConstants.CAP_NET_ADMIN, 481 OsConstants.CAP_NET_BIND_SERVICE, 482 OsConstants.CAP_NET_BROADCAST, 483 OsConstants.CAP_NET_RAW, 484 OsConstants.CAP_SYS_BOOT, 485 OsConstants.CAP_SYS_MODULE, 486 OsConstants.CAP_SYS_NICE, 487 OsConstants.CAP_SYS_RESOURCE, 488 OsConstants.CAP_SYS_TIME, 489 OsConstants.CAP_SYS_TTY_CONFIG 490 ); 491 /* Hardcoded command line to start the system server */ 492 String args[] = { 493 "--setuid=1000", 494 "--setgid=1000", 495 "--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,3001,3002,3003,3006,3007", 496 "--capabilities=" + capabilities + "," + capabilities, 497 "--runtime-init", 498 "--nice-name=system_server", 499 "com.android.server.SystemServer", 500 }; 501 ZygoteConnection.Arguments parsedArgs = null; 502 503 int pid; 504 505 try { 506 parsedArgs = new ZygoteConnection.Arguments(args); 507 ZygoteConnection.applyDebuggerSystemProperty(parsedArgs); 508 ZygoteConnection.applyInvokeWithSystemProperty(parsedArgs); 509 510 /* Request to fork the system server process */ 511 pid = Zygote.forkSystemServer( 512 parsedArgs.uid, parsedArgs.gid, 513 parsedArgs.gids, 514 parsedArgs.debugFlags, 515 null, 516 parsedArgs.permittedCapabilities, 517 parsedArgs.effectiveCapabilities); 518 } catch (IllegalArgumentException ex) { 519 throw new RuntimeException(ex); 520 } 521 522 /* For child process */ 523 if (pid == 0) { 524 handleSystemServerProcess(parsedArgs); 525 } 526 527 return true; 528 } 529 530 /** 531 * Gets the bit array representation of the provided list of POSIX capabilities. 532 */ 533 private static long posixCapabilitiesAsBits(int... capabilities) { 534 long result = 0; 535 for (int capability : capabilities) { 536 if ((capability < 0) || (capability > OsConstants.CAP_LAST_CAP)) { 537 throw new IllegalArgumentException(String.valueOf(capability)); 538 } 539 result |= (1L << capability); 540 } 541 return result; 542 } 543 544 public static void main(String argv[]) { 545 try { 546 // Start profiling the zygote initialization. 547 SamplingProfilerIntegration.start(); 548 549 registerZygoteSocket(); 550 EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_START, 551 SystemClock.uptimeMillis()); 552 preload(); 553 EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_END, 554 SystemClock.uptimeMillis()); 555 556 // Finish profiling the zygote initialization. 557 SamplingProfilerIntegration.writeZygoteSnapshot(); 558 559 // Do an initial gc to clean up after startup 560 gc(); 561 562 // Disable tracing so that forked processes do not inherit stale tracing tags from 563 // Zygote. 564 Trace.setTracingEnabled(false); 565 566 // If requested, start system server directly from Zygote 567 if (argv.length != 2) { 568 throw new RuntimeException(argv[0] + USAGE_STRING); 569 } 570 571 if (argv[1].equals("start-system-server")) { 572 startSystemServer(); 573 } else if (!argv[1].equals("")) { 574 throw new RuntimeException(argv[0] + USAGE_STRING); 575 } 576 577 Log.i(TAG, "Accepting command socket connections"); 578 579 runSelectLoop(); 580 581 closeServerSocket(); 582 } catch (MethodAndArgsCaller caller) { 583 caller.run(); 584 } catch (RuntimeException ex) { 585 Log.e(TAG, "Zygote died with exception", ex); 586 closeServerSocket(); 587 throw ex; 588 } 589 } 590 591 /** 592 * Runs the zygote process's select loop. Accepts new connections as 593 * they happen, and reads commands from connections one spawn-request's 594 * worth at a time. 595 * 596 * @throws MethodAndArgsCaller in a child process when a main() should 597 * be executed. 598 */ 599 private static void runSelectLoop() throws MethodAndArgsCaller { 600 ArrayList<FileDescriptor> fds = new ArrayList<FileDescriptor>(); 601 ArrayList<ZygoteConnection> peers = new ArrayList<ZygoteConnection>(); 602 FileDescriptor[] fdArray = new FileDescriptor[4]; 603 604 fds.add(sServerSocket.getFileDescriptor()); 605 peers.add(null); 606 607 int loopCount = GC_LOOP_COUNT; 608 while (true) { 609 int index; 610 611 /* 612 * Call gc() before we block in select(). 613 * It's work that has to be done anyway, and it's better 614 * to avoid making every child do it. It will also 615 * madvise() any free memory as a side-effect. 616 * 617 * Don't call it every time, because walking the entire 618 * heap is a lot of overhead to free a few hundred bytes. 619 */ 620 if (loopCount <= 0) { 621 gc(); 622 loopCount = GC_LOOP_COUNT; 623 } else { 624 loopCount--; 625 } 626 627 628 try { 629 fdArray = fds.toArray(fdArray); 630 index = selectReadable(fdArray); 631 } catch (IOException ex) { 632 throw new RuntimeException("Error in select()", ex); 633 } 634 635 if (index < 0) { 636 throw new RuntimeException("Error in select()"); 637 } else if (index == 0) { 638 ZygoteConnection newPeer = acceptCommandPeer(); 639 peers.add(newPeer); 640 fds.add(newPeer.getFileDesciptor()); 641 } else { 642 boolean done; 643 done = peers.get(index).runOnce(); 644 645 if (done) { 646 peers.remove(index); 647 fds.remove(index); 648 } 649 } 650 } 651 } 652 653 /** 654 * The Linux syscall "setreuid()" 655 * @param ruid real uid 656 * @param euid effective uid 657 * @return 0 on success, non-zero errno on fail 658 */ 659 static native int setreuid(int ruid, int euid); 660 661 /** 662 * The Linux syscall "setregid()" 663 * @param rgid real gid 664 * @param egid effective gid 665 * @return 0 on success, non-zero errno on fail 666 */ 667 static native int setregid(int rgid, int egid); 668 669 /** 670 * Invokes the linux syscall "setpgid" 671 * 672 * @param pid pid to change 673 * @param pgid new process group of pid 674 * @return 0 on success or non-zero errno on fail 675 */ 676 static native int setpgid(int pid, int pgid); 677 678 /** 679 * Invokes the linux syscall "getpgid" 680 * 681 * @param pid pid to query 682 * @return pgid of pid in question 683 * @throws IOException on error 684 */ 685 static native int getpgid(int pid) throws IOException; 686 687 /** 688 * Invokes the syscall dup2() to copy the specified descriptors into 689 * stdin, stdout, and stderr. The existing stdio descriptors will be 690 * closed and errors during close will be ignored. The specified 691 * descriptors will also remain open at their original descriptor numbers, 692 * so the caller may want to close the original descriptors. 693 * 694 * @param in new stdin 695 * @param out new stdout 696 * @param err new stderr 697 * @throws IOException 698 */ 699 static native void reopenStdio(FileDescriptor in, 700 FileDescriptor out, FileDescriptor err) throws IOException; 701 702 /** 703 * Toggles the close-on-exec flag for the specified file descriptor. 704 * 705 * @param fd non-null; file descriptor 706 * @param flag desired close-on-exec flag state 707 * @throws IOException 708 */ 709 static native void setCloseOnExec(FileDescriptor fd, boolean flag) 710 throws IOException; 711 712 /** 713 * Invokes select() on the provider array of file descriptors (selecting 714 * for readability only). Array elements of null are ignored. 715 * 716 * @param fds non-null; array of readable file descriptors 717 * @return index of descriptor that is now readable or -1 for empty array. 718 * @throws IOException if an error occurs 719 */ 720 static native int selectReadable(FileDescriptor[] fds) throws IOException; 721 722 /** 723 * Creates a file descriptor from an int fd. 724 * 725 * @param fd integer OS file descriptor 726 * @return non-null; FileDescriptor instance 727 * @throws IOException if fd is invalid 728 */ 729 static native FileDescriptor createFileDescriptor(int fd) 730 throws IOException; 731 732 /** 733 * Class not instantiable. 734 */ 735 private ZygoteInit() { 736 } 737 738 /** 739 * Helper exception class which holds a method and arguments and 740 * can call them. This is used as part of a trampoline to get rid of 741 * the initial process setup stack frames. 742 */ 743 public static class MethodAndArgsCaller extends Exception 744 implements Runnable { 745 /** method to call */ 746 private final Method mMethod; 747 748 /** argument array */ 749 private final String[] mArgs; 750 751 public MethodAndArgsCaller(Method method, String[] args) { 752 mMethod = method; 753 mArgs = args; 754 } 755 756 public void run() { 757 try { 758 mMethod.invoke(null, new Object[] { mArgs }); 759 } catch (IllegalAccessException ex) { 760 throw new RuntimeException(ex); 761 } catch (InvocationTargetException ex) { 762 Throwable cause = ex.getCause(); 763 if (cause instanceof RuntimeException) { 764 throw (RuntimeException) cause; 765 } else if (cause instanceof Error) { 766 throw (Error) cause; 767 } 768 throw new RuntimeException(ex); 769 } 770 } 771 } 772} 773