Process.java revision 54b6cfa9a9e5b861a9930af873580d6dc20f773c
1/* 2 * Copyright (C) 2006 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 android.os; 18 19import android.net.LocalSocketAddress; 20import android.net.LocalSocket; 21import android.util.Log; 22 23import java.io.BufferedWriter; 24import java.io.DataInputStream; 25import java.io.IOException; 26import java.io.OutputStreamWriter; 27import java.util.ArrayList; 28 29/*package*/ class ZygoteStartFailedEx extends Exception { 30 /** 31 * Something prevented the zygote process startup from happening normally 32 */ 33 34 ZygoteStartFailedEx() {}; 35 ZygoteStartFailedEx(String s) {super(s);} 36 ZygoteStartFailedEx(Throwable cause) {super(cause);} 37} 38 39/** 40 * Tools for managing OS processes. 41 */ 42public class Process { 43 private static final String LOG_TAG = "Process"; 44 45 private static final String ZYGOTE_SOCKET = "zygote"; 46 47 /** 48 * Name of a process for running the platform's media services. 49 * {@hide} 50 */ 51 public static final String ANDROID_SHARED_MEDIA = "com.android.process.media"; 52 53 /** 54 * Name of the process that Google content providers can share. 55 * {@hide} 56 */ 57 public static final String GOOGLE_SHARED_APP_CONTENT = "com.google.process.content"; 58 59 /** 60 * Defines the UID/GID under which system code runs. 61 */ 62 public static final int SYSTEM_UID = 1000; 63 64 /** 65 * Defines the UID/GID under which the telephony code runs. 66 */ 67 public static final int PHONE_UID = 1001; 68 69 /** 70 * Defines the start of a range of UIDs (and GIDs), going from this 71 * number to {@link #LAST_APPLICATION_UID} that are reserved for assigning 72 * to applications. 73 */ 74 public static final int FIRST_APPLICATION_UID = 10000; 75 /** 76 * Last of application-specific UIDs starting at 77 * {@link #FIRST_APPLICATION_UID}. 78 */ 79 public static final int LAST_APPLICATION_UID = 99999; 80 81 /** 82 * Defines a secondary group id for access to the bluetooth hardware. 83 */ 84 public static final int BLUETOOTH_GID = 2000; 85 86 /** 87 * Standard priority of application threads. 88 * Use with {@link #setThreadPriority(int)} and 89 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 90 * {@link java.lang.Thread} class. 91 */ 92 public static final int THREAD_PRIORITY_DEFAULT = 0; 93 94 /* 95 * *************************************** 96 * ** Keep in sync with utils/threads.h ** 97 * *************************************** 98 */ 99 100 /** 101 * Lowest available thread priority. Only for those who really, really 102 * don't want to run if anything else is happening. 103 * Use with {@link #setThreadPriority(int)} and 104 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 105 * {@link java.lang.Thread} class. 106 */ 107 public static final int THREAD_PRIORITY_LOWEST = 19; 108 109 /** 110 * Standard priority background threads. This gives your thread a slightly 111 * lower than normal priority, so that it will have less chance of impacting 112 * the responsiveness of the user interface. 113 * Use with {@link #setThreadPriority(int)} and 114 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 115 * {@link java.lang.Thread} class. 116 */ 117 public static final int THREAD_PRIORITY_BACKGROUND = 10; 118 119 /** 120 * Standard priority of threads that are currently running a user interface 121 * that the user is interacting with. Applications can not normally 122 * change to this priority; the system will automatically adjust your 123 * application threads as the user moves through the UI. 124 * Use with {@link #setThreadPriority(int)} and 125 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 126 * {@link java.lang.Thread} class. 127 */ 128 public static final int THREAD_PRIORITY_FOREGROUND = -2; 129 130 /** 131 * Standard priority of system display threads, involved in updating 132 * the user interface. Applications can not 133 * normally change to this priority. 134 * Use with {@link #setThreadPriority(int)} and 135 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 136 * {@link java.lang.Thread} class. 137 */ 138 public static final int THREAD_PRIORITY_DISPLAY = -4; 139 140 /** 141 * Standard priority of the most important display threads, for compositing 142 * the screen and retrieving input events. Applications can not normally 143 * change to this priority. 144 * Use with {@link #setThreadPriority(int)} and 145 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 146 * {@link java.lang.Thread} class. 147 */ 148 public static final int THREAD_PRIORITY_URGENT_DISPLAY = -8; 149 150 /** 151 * Standard priority of audio threads. Applications can not normally 152 * change to this priority. 153 * Use with {@link #setThreadPriority(int)} and 154 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 155 * {@link java.lang.Thread} class. 156 */ 157 public static final int THREAD_PRIORITY_AUDIO = -16; 158 159 /** 160 * Standard priority of the most important audio threads. 161 * Applications can not normally change to this priority. 162 * Use with {@link #setThreadPriority(int)} and 163 * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal 164 * {@link java.lang.Thread} class. 165 */ 166 public static final int THREAD_PRIORITY_URGENT_AUDIO = -19; 167 168 /** 169 * Minimum increment to make a priority more favorable. 170 */ 171 public static final int THREAD_PRIORITY_MORE_FAVORABLE = -1; 172 173 /** 174 * Minimum increment to make a priority less favorable. 175 */ 176 public static final int THREAD_PRIORITY_LESS_FAVORABLE = +1; 177 178 public static final int SIGNAL_QUIT = 3; 179 public static final int SIGNAL_KILL = 9; 180 public static final int SIGNAL_USR1 = 10; 181 182 // State for communicating with zygote process 183 184 static LocalSocket sZygoteSocket; 185 static DataInputStream sZygoteInputStream; 186 static BufferedWriter sZygoteWriter; 187 188 /** true if previous zygote open failed */ 189 static boolean sPreviousZygoteOpenFailed; 190 191 /** 192 * Start a new process. 193 * 194 * <p>If processes are enabled, a new process is created and the 195 * static main() function of a <var>processClass</var> is executed there. 196 * The process will continue running after this function returns. 197 * 198 * <p>If processes are not enabled, a new thread in the caller's 199 * process is created and main() of <var>processClass</var> called there. 200 * 201 * <p>The niceName parameter, if not an empty string, is a custom name to 202 * give to the process instead of using processClass. This allows you to 203 * make easily identifyable processes even if you are using the same base 204 * <var>processClass</var> to start them. 205 * 206 * @param processClass The class to use as the process's main entry 207 * point. 208 * @param niceName A more readable name to use for the process. 209 * @param uid The user-id under which the process will run. 210 * @param gid The group-id under which the process will run. 211 * @param gids Additional group-ids associated with the process. 212 * @param enableDebugger True if debugging should be enabled for this process. 213 * @param zygoteArgs Additional arguments to supply to the zygote process. 214 * 215 * @return int If > 0 the pid of the new process; if 0 the process is 216 * being emulated by a thread 217 * @throws RuntimeException on fatal start failure 218 * 219 * {@hide} 220 */ 221 public static final int start(final String processClass, 222 final String niceName, 223 int uid, int gid, int[] gids, 224 boolean enableDebugger, 225 String[] zygoteArgs) 226 { 227 if (supportsProcesses()) { 228 try { 229 return startViaZygote(processClass, niceName, uid, gid, gids, 230 enableDebugger, zygoteArgs); 231 } catch (ZygoteStartFailedEx ex) { 232 Log.e(LOG_TAG, 233 "Starting VM process through Zygote failed"); 234 throw new RuntimeException( 235 "Starting VM process through Zygote failed", ex); 236 } 237 } else { 238 // Running in single-process mode 239 240 Runnable runnable = new Runnable() { 241 public void run() { 242 Process.invokeStaticMain(processClass); 243 } 244 }; 245 246 // Thread constructors must not be called with null names (see spec). 247 if (niceName != null) { 248 new Thread(runnable, niceName).start(); 249 } else { 250 new Thread(runnable).start(); 251 } 252 253 return 0; 254 } 255 } 256 257 /** 258 * Start a new process. Don't supply a custom nice name. 259 * {@hide} 260 */ 261 public static final int start(String processClass, int uid, int gid, 262 int[] gids, boolean enableDebugger, String[] zygoteArgs) { 263 return start(processClass, "", uid, gid, gids, 264 enableDebugger, zygoteArgs); 265 } 266 267 private static void invokeStaticMain(String className) { 268 Class cl; 269 Object args[] = new Object[1]; 270 271 args[0] = new String[0]; //this is argv 272 273 try { 274 cl = Class.forName(className); 275 cl.getMethod("main", new Class[] { String[].class }) 276 .invoke(null, args); 277 } catch (Exception ex) { 278 // can be: ClassNotFoundException, 279 // NoSuchMethodException, SecurityException, 280 // IllegalAccessException, IllegalArgumentException 281 // InvocationTargetException 282 // or uncaught exception from main() 283 284 Log.e(LOG_TAG, "Exception invoking static main on " 285 + className, ex); 286 287 throw new RuntimeException(ex); 288 } 289 290 } 291 292 /** retry interval for opening a zygote socket */ 293 static final int ZYGOTE_RETRY_MILLIS = 500; 294 295 /** 296 * Tries to open socket to Zygote process if not already open. If 297 * already open, does nothing. May block and retry. 298 */ 299 private static void openZygoteSocketIfNeeded() 300 throws ZygoteStartFailedEx { 301 302 int retryCount; 303 304 if (sPreviousZygoteOpenFailed) { 305 /* 306 * If we've failed before, expect that we'll fail again and 307 * don't pause for retries. 308 */ 309 retryCount = 0; 310 } else { 311 retryCount = 10; 312 } 313 314 /* 315 * See bug #811181: Sometimes runtime can make it up before zygote. 316 * Really, we'd like to do something better to avoid this condition, 317 * but for now just wait a bit... 318 */ 319 for (int retry = 0 320 ; (sZygoteSocket == null) && (retry < (retryCount + 1)) 321 ; retry++ ) { 322 323 if (retry > 0) { 324 try { 325 Log.i("Zygote", "Zygote not up yet, sleeping..."); 326 Thread.sleep(ZYGOTE_RETRY_MILLIS); 327 } catch (InterruptedException ex) { 328 // should never happen 329 } 330 } 331 332 try { 333 sZygoteSocket = new LocalSocket(); 334 335 sZygoteSocket.connect(new LocalSocketAddress(ZYGOTE_SOCKET, 336 LocalSocketAddress.Namespace.RESERVED)); 337 338 sZygoteInputStream 339 = new DataInputStream(sZygoteSocket.getInputStream()); 340 341 sZygoteWriter = 342 new BufferedWriter( 343 new OutputStreamWriter( 344 sZygoteSocket.getOutputStream()), 345 256); 346 347 Log.i("Zygote", "Process: zygote socket opened"); 348 349 sPreviousZygoteOpenFailed = false; 350 break; 351 } catch (IOException ex) { 352 if (sZygoteSocket != null) { 353 try { 354 sZygoteSocket.close(); 355 } catch (IOException ex2) { 356 Log.e(LOG_TAG,"I/O exception on close after exception", 357 ex2); 358 } 359 } 360 361 sZygoteSocket = null; 362 } 363 } 364 365 if (sZygoteSocket == null) { 366 sPreviousZygoteOpenFailed = true; 367 throw new ZygoteStartFailedEx("connect failed"); 368 } 369 } 370 371 /** 372 * Sends an argument list to the zygote process, which starts a new child 373 * and returns the child's pid. Please note: the present implementation 374 * replaces newlines in the argument list with spaces. 375 * @param args argument list 376 * @return PID of new child process 377 * @throws ZygoteStartFailedEx if process start failed for any reason 378 */ 379 private static int zygoteSendArgsAndGetPid(ArrayList<String> args) 380 throws ZygoteStartFailedEx { 381 382 int pid; 383 384 openZygoteSocketIfNeeded(); 385 386 try { 387 /** 388 * See com.android.internal.os.ZygoteInit.readArgumentList() 389 * Presently the wire format to the zygote process is: 390 * a) a count of arguments (argc, in essence) 391 * b) a number of newline-separated argument strings equal to count 392 * 393 * After the zygote process reads these it will write the pid of 394 * the child or -1 on failure. 395 */ 396 397 sZygoteWriter.write(Integer.toString(args.size())); 398 sZygoteWriter.newLine(); 399 400 int sz = args.size(); 401 for (int i = 0; i < sz; i++) { 402 String arg = args.get(i); 403 if (arg.indexOf('\n') >= 0) { 404 throw new ZygoteStartFailedEx( 405 "embedded newlines not allowed"); 406 } 407 sZygoteWriter.write(arg); 408 sZygoteWriter.newLine(); 409 } 410 411 sZygoteWriter.flush(); 412 413 // Should there be a timeout on this? 414 pid = sZygoteInputStream.readInt(); 415 416 if (pid < 0) { 417 throw new ZygoteStartFailedEx("fork() failed"); 418 } 419 } catch (IOException ex) { 420 try { 421 if (sZygoteSocket != null) { 422 sZygoteSocket.close(); 423 } 424 } catch (IOException ex2) { 425 // we're going to fail anyway 426 Log.e(LOG_TAG,"I/O exception on routine close", ex2); 427 } 428 429 sZygoteSocket = null; 430 431 throw new ZygoteStartFailedEx(ex); 432 } 433 434 return pid; 435 } 436 437 /** 438 * Starts a new process via the zygote mechanism. 439 * 440 * @param processClass Class name whose static main() to run 441 * @param niceName 'nice' process name to appear in ps 442 * @param uid a POSIX uid that the new process should setuid() to 443 * @param gid a POSIX gid that the new process shuold setgid() to 444 * @param gids null-ok; a list of supplementary group IDs that the 445 * new process should setgroup() to. 446 * @param enableDebugger True if debugging should be enabled for this process. 447 * @param extraArgs Additional arguments to supply to the zygote process. 448 * @return PID 449 * @throws ZygoteStartFailedEx if process start failed for any reason 450 */ 451 private static int startViaZygote(final String processClass, 452 final String niceName, 453 final int uid, final int gid, 454 final int[] gids, 455 boolean enableDebugger, 456 String[] extraArgs) 457 throws ZygoteStartFailedEx { 458 int pid; 459 460 synchronized(Process.class) { 461 ArrayList<String> argsForZygote = new ArrayList<String>(); 462 463 // --runtime-init, --setuid=, --setgid=, 464 // and --setgroups= must go first 465 argsForZygote.add("--runtime-init"); 466 argsForZygote.add("--setuid=" + uid); 467 argsForZygote.add("--setgid=" + gid); 468 if (enableDebugger) { 469 argsForZygote.add("--enable-debugger"); 470 } 471 472 //TODO optionally enable debuger 473 //argsForZygote.add("--enable-debugger"); 474 475 // --setgroups is a comma-separated list 476 if (gids != null && gids.length > 0) { 477 StringBuilder sb = new StringBuilder(); 478 sb.append("--setgroups="); 479 480 int sz = gids.length; 481 for (int i = 0; i < sz; i++) { 482 if (i != 0) { 483 sb.append(','); 484 } 485 sb.append(gids[i]); 486 } 487 488 argsForZygote.add(sb.toString()); 489 } 490 491 if (niceName != null) { 492 argsForZygote.add("--nice-name=" + niceName); 493 } 494 495 argsForZygote.add(processClass); 496 497 if (extraArgs != null) { 498 for (String arg : extraArgs) { 499 argsForZygote.add(arg); 500 } 501 } 502 503 pid = zygoteSendArgsAndGetPid(argsForZygote); 504 } 505 506 if (pid <= 0) { 507 throw new ZygoteStartFailedEx("zygote start failed:" + pid); 508 } 509 510 return pid; 511 } 512 513 /** 514 * Returns elapsed milliseconds of the time this process has run. 515 * @return Returns the number of milliseconds this process has return. 516 */ 517 public static final native long getElapsedCpuTime(); 518 519 /** 520 * Returns the identifier of this process, which can be used with 521 * {@link #killProcess} and {@link #sendSignal}. 522 */ 523 public static final native int myPid(); 524 525 /** 526 * Returns the identifier of the calling thread, which be used with 527 * {@link #setThreadPriority(int, int)}. 528 */ 529 public static final native int myTid(); 530 531 /** 532 * Returns the UID assigned to a partlicular user name, or -1 if there is 533 * none. If the given string consists of only numbers, it is converted 534 * directly to a uid. 535 */ 536 public static final native int getUidForName(String name); 537 538 /** 539 * Returns the GID assigned to a particular user name, or -1 if there is 540 * none. If the given string consists of only numbers, it is converted 541 * directly to a gid. 542 */ 543 public static final native int getGidForName(String name); 544 545 /** 546 * Set the priority of a thread, based on Linux priorities. 547 * 548 * @param tid The identifier of the thread/process to change. 549 * @param priority A Linux priority level, from -20 for highest scheduling 550 * priority to 19 for lowest scheduling priority. 551 * 552 * @throws IllegalArgumentException Throws IllegalArgumentException if 553 * <var>tid</var> does not exist. 554 * @throws SecurityException Throws SecurityException if your process does 555 * not have permission to modify the given thread, or to use the given 556 * priority. 557 */ 558 public static final native void setThreadPriority(int tid, int priority) 559 throws IllegalArgumentException, SecurityException; 560 561 /** 562 * Set the priority of the calling thread, based on Linux priorities. See 563 * {@link #setThreadPriority(int, int)} for more information. 564 * 565 * @param priority A Linux priority level, from -20 for highest scheduling 566 * priority to 19 for lowest scheduling priority. 567 * 568 * @throws IllegalArgumentException Throws IllegalArgumentException if 569 * <var>tid</var> does not exist. 570 * @throws SecurityException Throws SecurityException if your process does 571 * not have permission to modify the given thread, or to use the given 572 * priority. 573 * 574 * @see #setThreadPriority(int, int) 575 */ 576 public static final native void setThreadPriority(int priority) 577 throws IllegalArgumentException, SecurityException; 578 579 /** 580 * Return the current priority of a thread, based on Linux priorities. 581 * 582 * @param tid The identifier of the thread/process to change. 583 * 584 * @return Returns the current priority, as a Linux priority level, 585 * from -20 for highest scheduling priority to 19 for lowest scheduling 586 * priority. 587 * 588 * @throws IllegalArgumentException Throws IllegalArgumentException if 589 * <var>tid</var> does not exist. 590 */ 591 public static final native int getThreadPriority(int tid) 592 throws IllegalArgumentException; 593 594 /** 595 * Determine whether the current environment supports multiple processes. 596 * 597 * @return Returns true if the system can run in multiple processes, else 598 * false if everything is running in a single process. 599 */ 600 public static final native boolean supportsProcesses(); 601 602 /** 603 * Set the out-of-memory badness adjustment for a process. 604 * 605 * @param pid The process identifier to set. 606 * @param amt Adjustment value -- linux allows -16 to +15. 607 * 608 * @return Returns true if the underlying system supports this 609 * feature, else false. 610 * 611 * {@hide} 612 */ 613 public static final native boolean setOomAdj(int pid, int amt); 614 615 /** 616 * Change this process's argv[0] parameter. This can be useful to show 617 * more descriptive information in things like the 'ps' command. 618 * 619 * @param text The new name of this process. 620 * 621 * {@hide} 622 */ 623 public static final native void setArgV0(String text); 624 625 /** 626 * Kill the process with the given PID. 627 * Note that, though this API allows us to request to 628 * kill any process based on its PID, the kernel will 629 * still impose standard restrictions on which PIDs you 630 * are actually able to kill. Typically this means only 631 * the process running the caller's packages/application 632 * and any additional processes created by that app; packages 633 * sharing a common UID will also be able to kill each 634 * other's processes. 635 */ 636 public static final void killProcess(int pid) { 637 sendSignal(pid, SIGNAL_KILL); 638 } 639 640 /** @hide */ 641 public static final native int setUid(int uid); 642 643 /** @hide */ 644 public static final native int setGid(int uid); 645 646 /** 647 * Send a signal to the given process. 648 * 649 * @param pid The pid of the target process. 650 * @param signal The signal to send. 651 */ 652 public static final native void sendSignal(int pid, int signal); 653 654 /** @hide */ 655 public static final native int getFreeMemory(); 656 657 /** @hide */ 658 public static final native void readProcLines(String path, 659 String[] reqFields, long[] outSizes); 660 661 /** @hide */ 662 public static final native int[] getPids(String path, int[] lastArray); 663 664 /** @hide */ 665 public static final int PROC_TERM_MASK = 0xff; 666 /** @hide */ 667 public static final int PROC_ZERO_TERM = 0; 668 /** @hide */ 669 public static final int PROC_SPACE_TERM = (int)' '; 670 /** @hide */ 671 public static final int PROC_COMBINE = 0x100; 672 /** @hide */ 673 public static final int PROC_PARENS = 0x200; 674 /** @hide */ 675 public static final int PROC_OUT_STRING = 0x1000; 676 /** @hide */ 677 public static final int PROC_OUT_LONG = 0x2000; 678 /** @hide */ 679 public static final int PROC_OUT_FLOAT = 0x4000; 680 681 /** @hide */ 682 public static final native boolean readProcFile(String file, int[] format, 683 String[] outStrings, long[] outLongs, float[] outFloats); 684 685 /** 686 * Gets the total Pss value for a given process, in bytes. 687 * 688 * @param pid the process to the Pss for 689 * @return the total Pss value for the given process in bytes, 690 * or -1 if the value cannot be determined 691 * @hide 692 */ 693 public static final native long getPss(int pid); 694} 695