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      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 
     17 package android.os;
     18 
     19 import android.net.LocalSocketAddress;
     20 import android.net.LocalSocket;
     21 import android.util.Log;
     22 import dalvik.system.Zygote;
     23 
     24 import java.io.BufferedWriter;
     25 import java.io.DataInputStream;
     26 import java.io.IOException;
     27 import java.io.OutputStreamWriter;
     28 import java.util.ArrayList;
     29 
     30 /*package*/ class ZygoteStartFailedEx extends Exception {
     31     /**
     32      * Something prevented the zygote process startup from happening normally
     33      */
     34 
     35     ZygoteStartFailedEx() {};
     36     ZygoteStartFailedEx(String s) {super(s);}
     37     ZygoteStartFailedEx(Throwable cause) {super(cause);}
     38 }
     39 
     40 /**
     41  * Tools for managing OS processes.
     42  */
     43 public class Process {
     44     private static final String LOG_TAG = "Process";
     45 
     46     private static final String ZYGOTE_SOCKET = "zygote";
     47 
     48     /**
     49      * Name of a process for running the platform's media services.
     50      * {@hide}
     51      */
     52     public static final String ANDROID_SHARED_MEDIA = "com.android.process.media";
     53 
     54     /**
     55      * Name of the process that Google content providers can share.
     56      * {@hide}
     57      */
     58     public static final String GOOGLE_SHARED_APP_CONTENT = "com.google.process.content";
     59 
     60     /**
     61      * Defines the UID/GID under which system code runs.
     62      */
     63     public static final int SYSTEM_UID = 1000;
     64 
     65     /**
     66      * Defines the UID/GID under which the telephony code runs.
     67      */
     68     public static final int PHONE_UID = 1001;
     69 
     70     /**
     71      * Defines the UID/GID for the user shell.
     72      * @hide
     73      */
     74     public static final int SHELL_UID = 2000;
     75 
     76     /**
     77      * Defines the UID/GID for the log group.
     78      * @hide
     79      */
     80     public static final int LOG_UID = 1007;
     81 
     82     /**
     83      * Defines the UID/GID for the WIFI supplicant process.
     84      * @hide
     85      */
     86     public static final int WIFI_UID = 1010;
     87 
     88     /**
     89      * Defines the UID/GID for the mediaserver process.
     90      * @hide
     91      */
     92     public static final int MEDIA_UID = 1013;
     93 
     94     /**
     95      * Defines the UID/GID for the DRM process.
     96      * @hide
     97      */
     98     public static final int DRM_UID = 1019;
     99 
    100     /**
    101      * Defines the GID for the group that allows write access to the SD card.
    102      * @hide
    103      */
    104     public static final int SDCARD_RW_GID = 1015;
    105 
    106     /**
    107      * Defines the UID/GID for the group that controls VPN services.
    108      * @hide
    109      */
    110     public static final int VPN_UID = 1016;
    111 
    112     /**
    113      * Defines the UID/GID for the NFC service process.
    114      * @hide
    115      */
    116     public static final int NFC_UID = 1027;
    117 
    118     /**
    119      * Defines the UID/GID for the Bluetooth service process.
    120      * @hide
    121      */
    122     public static final int BLUETOOTH_UID = 1002;
    123 
    124     /**
    125      * Defines the GID for the group that allows write access to the internal media storage.
    126      * @hide
    127      */
    128     public static final int MEDIA_RW_GID = 1023;
    129 
    130     /**
    131      * Defines the start of a range of UIDs (and GIDs), going from this
    132      * number to {@link #LAST_APPLICATION_UID} that are reserved for assigning
    133      * to applications.
    134      */
    135     public static final int FIRST_APPLICATION_UID = 10000;
    136     /**
    137      * Last of application-specific UIDs starting at
    138      * {@link #FIRST_APPLICATION_UID}.
    139      */
    140     public static final int LAST_APPLICATION_UID = 19999;
    141 
    142     /**
    143      * First uid used for fully isolated sandboxed processes (with no permissions of their own)
    144      * @hide
    145      */
    146     public static final int FIRST_ISOLATED_UID = 99000;
    147 
    148     /**
    149      * Last uid used for fully isolated sandboxed processes (with no permissions of their own)
    150      * @hide
    151      */
    152     public static final int LAST_ISOLATED_UID = 99999;
    153 
    154     /**
    155      * First gid for applications to share resources. Used when forward-locking
    156      * is enabled but all UserHandles need to be able to read the resources.
    157      * @hide
    158      */
    159     public static final int FIRST_SHARED_APPLICATION_GID = 50000;
    160 
    161     /**
    162      * Last gid for applications to share resources. Used when forward-locking
    163      * is enabled but all UserHandles need to be able to read the resources.
    164      * @hide
    165      */
    166     public static final int LAST_SHARED_APPLICATION_GID = 59999;
    167 
    168     /**
    169      * Standard priority of application threads.
    170      * Use with {@link #setThreadPriority(int)} and
    171      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    172      * {@link java.lang.Thread} class.
    173      */
    174     public static final int THREAD_PRIORITY_DEFAULT = 0;
    175 
    176     /*
    177      * ***************************************
    178      * ** Keep in sync with utils/threads.h **
    179      * ***************************************
    180      */
    181 
    182     /**
    183      * Lowest available thread priority.  Only for those who really, really
    184      * don't want to run if anything else is happening.
    185      * Use with {@link #setThreadPriority(int)} and
    186      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    187      * {@link java.lang.Thread} class.
    188      */
    189     public static final int THREAD_PRIORITY_LOWEST = 19;
    190 
    191     /**
    192      * Standard priority background threads.  This gives your thread a slightly
    193      * lower than normal priority, so that it will have less chance of impacting
    194      * the responsiveness of the user interface.
    195      * Use with {@link #setThreadPriority(int)} and
    196      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    197      * {@link java.lang.Thread} class.
    198      */
    199     public static final int THREAD_PRIORITY_BACKGROUND = 10;
    200 
    201     /**
    202      * Standard priority of threads that are currently running a user interface
    203      * that the user is interacting with.  Applications can not normally
    204      * change to this priority; the system will automatically adjust your
    205      * application threads as the user moves through the UI.
    206      * Use with {@link #setThreadPriority(int)} and
    207      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    208      * {@link java.lang.Thread} class.
    209      */
    210     public static final int THREAD_PRIORITY_FOREGROUND = -2;
    211 
    212     /**
    213      * Standard priority of system display threads, involved in updating
    214      * the user interface.  Applications can not
    215      * normally change to this priority.
    216      * Use with {@link #setThreadPriority(int)} and
    217      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    218      * {@link java.lang.Thread} class.
    219      */
    220     public static final int THREAD_PRIORITY_DISPLAY = -4;
    221 
    222     /**
    223      * Standard priority of the most important display threads, for compositing
    224      * the screen and retrieving input events.  Applications can not normally
    225      * change to this priority.
    226      * Use with {@link #setThreadPriority(int)} and
    227      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    228      * {@link java.lang.Thread} class.
    229      */
    230     public static final int THREAD_PRIORITY_URGENT_DISPLAY = -8;
    231 
    232     /**
    233      * Standard priority of audio threads.  Applications can not normally
    234      * change to this priority.
    235      * Use with {@link #setThreadPriority(int)} and
    236      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    237      * {@link java.lang.Thread} class.
    238      */
    239     public static final int THREAD_PRIORITY_AUDIO = -16;
    240 
    241     /**
    242      * Standard priority of the most important audio threads.
    243      * Applications can not normally change to this priority.
    244      * Use with {@link #setThreadPriority(int)} and
    245      * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
    246      * {@link java.lang.Thread} class.
    247      */
    248     public static final int THREAD_PRIORITY_URGENT_AUDIO = -19;
    249 
    250     /**
    251      * Minimum increment to make a priority more favorable.
    252      */
    253     public static final int THREAD_PRIORITY_MORE_FAVORABLE = -1;
    254 
    255     /**
    256      * Minimum increment to make a priority less favorable.
    257      */
    258     public static final int THREAD_PRIORITY_LESS_FAVORABLE = +1;
    259 
    260     /**
    261      * Default scheduling policy
    262      * @hide
    263      */
    264     public static final int SCHED_OTHER = 0;
    265 
    266     /**
    267      * First-In First-Out scheduling policy
    268      * @hide
    269      */
    270     public static final int SCHED_FIFO = 1;
    271 
    272     /**
    273      * Round-Robin scheduling policy
    274      * @hide
    275      */
    276     public static final int SCHED_RR = 2;
    277 
    278     /**
    279      * Batch scheduling policy
    280      * @hide
    281      */
    282     public static final int SCHED_BATCH = 3;
    283 
    284     /**
    285      * Idle scheduling policy
    286      * @hide
    287      */
    288     public static final int SCHED_IDLE = 5;
    289 
    290     // Keep in sync with SP_* constants of enum type SchedPolicy
    291     // declared in system/core/include/cutils/sched_policy.h,
    292     // except THREAD_GROUP_DEFAULT does not correspond to any SP_* value.
    293 
    294     /**
    295      * Default thread group -
    296      * has meaning with setProcessGroup() only, cannot be used with setThreadGroup().
    297      * When used with setProcessGroup(), the group of each thread in the process
    298      * is conditionally changed based on that thread's current priority, as follows:
    299      * threads with priority numerically less than THREAD_PRIORITY_BACKGROUND
    300      * are moved to foreground thread group.  All other threads are left unchanged.
    301      * @hide
    302      */
    303     public static final int THREAD_GROUP_DEFAULT = -1;
    304 
    305     /**
    306      * Background thread group - All threads in
    307      * this group are scheduled with a reduced share of the CPU.
    308      * Value is same as constant SP_BACKGROUND of enum SchedPolicy.
    309      * FIXME rename to THREAD_GROUP_BACKGROUND.
    310      * @hide
    311      */
    312     public static final int THREAD_GROUP_BG_NONINTERACTIVE = 0;
    313 
    314     /**
    315      * Foreground thread group - All threads in
    316      * this group are scheduled with a normal share of the CPU.
    317      * Value is same as constant SP_FOREGROUND of enum SchedPolicy.
    318      * Not used at this level.
    319      * @hide
    320      **/
    321     private static final int THREAD_GROUP_FOREGROUND = 1;
    322 
    323     /**
    324      * System thread group.
    325      * @hide
    326      **/
    327     public static final int THREAD_GROUP_SYSTEM = 2;
    328 
    329     /**
    330      * Application audio thread group.
    331      * @hide
    332      **/
    333     public static final int THREAD_GROUP_AUDIO_APP = 3;
    334 
    335     /**
    336      * System audio thread group.
    337      * @hide
    338      **/
    339     public static final int THREAD_GROUP_AUDIO_SYS = 4;
    340 
    341     public static final int SIGNAL_QUIT = 3;
    342     public static final int SIGNAL_KILL = 9;
    343     public static final int SIGNAL_USR1 = 10;
    344 
    345     // State for communicating with zygote process
    346 
    347     static LocalSocket sZygoteSocket;
    348     static DataInputStream sZygoteInputStream;
    349     static BufferedWriter sZygoteWriter;
    350 
    351     /** true if previous zygote open failed */
    352     static boolean sPreviousZygoteOpenFailed;
    353 
    354     /**
    355      * Start a new process.
    356      *
    357      * <p>If processes are enabled, a new process is created and the
    358      * static main() function of a <var>processClass</var> is executed there.
    359      * The process will continue running after this function returns.
    360      *
    361      * <p>If processes are not enabled, a new thread in the caller's
    362      * process is created and main() of <var>processClass</var> called there.
    363      *
    364      * <p>The niceName parameter, if not an empty string, is a custom name to
    365      * give to the process instead of using processClass.  This allows you to
    366      * make easily identifyable processes even if you are using the same base
    367      * <var>processClass</var> to start them.
    368      *
    369      * @param processClass The class to use as the process's main entry
    370      *                     point.
    371      * @param niceName A more readable name to use for the process.
    372      * @param uid The user-id under which the process will run.
    373      * @param gid The group-id under which the process will run.
    374      * @param gids Additional group-ids associated with the process.
    375      * @param debugFlags Additional flags.
    376      * @param targetSdkVersion The target SDK version for the app.
    377      * @param seInfo null-ok SE Android information for the new process.
    378      * @param zygoteArgs Additional arguments to supply to the zygote process.
    379      *
    380      * @return An object that describes the result of the attempt to start the process.
    381      * @throws RuntimeException on fatal start failure
    382      *
    383      * {@hide}
    384      */
    385     public static final ProcessStartResult start(final String processClass,
    386                                   final String niceName,
    387                                   int uid, int gid, int[] gids,
    388                                   int debugFlags, int mountExternal,
    389                                   int targetSdkVersion,
    390                                   String seInfo,
    391                                   String[] zygoteArgs) {
    392         try {
    393             return startViaZygote(processClass, niceName, uid, gid, gids,
    394                     debugFlags, mountExternal, targetSdkVersion, seInfo, zygoteArgs);
    395         } catch (ZygoteStartFailedEx ex) {
    396             Log.e(LOG_TAG,
    397                     "Starting VM process through Zygote failed");
    398             throw new RuntimeException(
    399                     "Starting VM process through Zygote failed", ex);
    400         }
    401     }
    402 
    403     /** retry interval for opening a zygote socket */
    404     static final int ZYGOTE_RETRY_MILLIS = 500;
    405 
    406     /**
    407      * Tries to open socket to Zygote process if not already open. If
    408      * already open, does nothing.  May block and retry.
    409      */
    410     private static void openZygoteSocketIfNeeded()
    411             throws ZygoteStartFailedEx {
    412 
    413         int retryCount;
    414 
    415         if (sPreviousZygoteOpenFailed) {
    416             /*
    417              * If we've failed before, expect that we'll fail again and
    418              * don't pause for retries.
    419              */
    420             retryCount = 0;
    421         } else {
    422             retryCount = 10;
    423         }
    424 
    425         /*
    426          * See bug #811181: Sometimes runtime can make it up before zygote.
    427          * Really, we'd like to do something better to avoid this condition,
    428          * but for now just wait a bit...
    429          */
    430         for (int retry = 0
    431                 ; (sZygoteSocket == null) && (retry < (retryCount + 1))
    432                 ; retry++ ) {
    433 
    434             if (retry > 0) {
    435                 try {
    436                     Log.i("Zygote", "Zygote not up yet, sleeping...");
    437                     Thread.sleep(ZYGOTE_RETRY_MILLIS);
    438                 } catch (InterruptedException ex) {
    439                     // should never happen
    440                 }
    441             }
    442 
    443             try {
    444                 sZygoteSocket = new LocalSocket();
    445 
    446                 sZygoteSocket.connect(new LocalSocketAddress(ZYGOTE_SOCKET,
    447                         LocalSocketAddress.Namespace.RESERVED));
    448 
    449                 sZygoteInputStream
    450                         = new DataInputStream(sZygoteSocket.getInputStream());
    451 
    452                 sZygoteWriter =
    453                     new BufferedWriter(
    454                             new OutputStreamWriter(
    455                                     sZygoteSocket.getOutputStream()),
    456                             256);
    457 
    458                 Log.i("Zygote", "Process: zygote socket opened");
    459 
    460                 sPreviousZygoteOpenFailed = false;
    461                 break;
    462             } catch (IOException ex) {
    463                 if (sZygoteSocket != null) {
    464                     try {
    465                         sZygoteSocket.close();
    466                     } catch (IOException ex2) {
    467                         Log.e(LOG_TAG,"I/O exception on close after exception",
    468                                 ex2);
    469                     }
    470                 }
    471 
    472                 sZygoteSocket = null;
    473             }
    474         }
    475 
    476         if (sZygoteSocket == null) {
    477             sPreviousZygoteOpenFailed = true;
    478             throw new ZygoteStartFailedEx("connect failed");
    479         }
    480     }
    481 
    482     /**
    483      * Sends an argument list to the zygote process, which starts a new child
    484      * and returns the child's pid. Please note: the present implementation
    485      * replaces newlines in the argument list with spaces.
    486      * @param args argument list
    487      * @return An object that describes the result of the attempt to start the process.
    488      * @throws ZygoteStartFailedEx if process start failed for any reason
    489      */
    490     private static ProcessStartResult zygoteSendArgsAndGetResult(ArrayList<String> args)
    491             throws ZygoteStartFailedEx {
    492         openZygoteSocketIfNeeded();
    493 
    494         try {
    495             /**
    496              * See com.android.internal.os.ZygoteInit.readArgumentList()
    497              * Presently the wire format to the zygote process is:
    498              * a) a count of arguments (argc, in essence)
    499              * b) a number of newline-separated argument strings equal to count
    500              *
    501              * After the zygote process reads these it will write the pid of
    502              * the child or -1 on failure, followed by boolean to
    503              * indicate whether a wrapper process was used.
    504              */
    505 
    506             sZygoteWriter.write(Integer.toString(args.size()));
    507             sZygoteWriter.newLine();
    508 
    509             int sz = args.size();
    510             for (int i = 0; i < sz; i++) {
    511                 String arg = args.get(i);
    512                 if (arg.indexOf('\n') >= 0) {
    513                     throw new ZygoteStartFailedEx(
    514                             "embedded newlines not allowed");
    515                 }
    516                 sZygoteWriter.write(arg);
    517                 sZygoteWriter.newLine();
    518             }
    519 
    520             sZygoteWriter.flush();
    521 
    522             // Should there be a timeout on this?
    523             ProcessStartResult result = new ProcessStartResult();
    524             result.pid = sZygoteInputStream.readInt();
    525             if (result.pid < 0) {
    526                 throw new ZygoteStartFailedEx("fork() failed");
    527             }
    528             result.usingWrapper = sZygoteInputStream.readBoolean();
    529             return result;
    530         } catch (IOException ex) {
    531             try {
    532                 if (sZygoteSocket != null) {
    533                     sZygoteSocket.close();
    534                 }
    535             } catch (IOException ex2) {
    536                 // we're going to fail anyway
    537                 Log.e(LOG_TAG,"I/O exception on routine close", ex2);
    538             }
    539 
    540             sZygoteSocket = null;
    541 
    542             throw new ZygoteStartFailedEx(ex);
    543         }
    544     }
    545 
    546     /**
    547      * Starts a new process via the zygote mechanism.
    548      *
    549      * @param processClass Class name whose static main() to run
    550      * @param niceName 'nice' process name to appear in ps
    551      * @param uid a POSIX uid that the new process should setuid() to
    552      * @param gid a POSIX gid that the new process shuold setgid() to
    553      * @param gids null-ok; a list of supplementary group IDs that the
    554      * new process should setgroup() to.
    555      * @param debugFlags Additional flags.
    556      * @param targetSdkVersion The target SDK version for the app.
    557      * @param seInfo null-ok SE Android information for the new process.
    558      * @param extraArgs Additional arguments to supply to the zygote process.
    559      * @return An object that describes the result of the attempt to start the process.
    560      * @throws ZygoteStartFailedEx if process start failed for any reason
    561      */
    562     private static ProcessStartResult startViaZygote(final String processClass,
    563                                   final String niceName,
    564                                   final int uid, final int gid,
    565                                   final int[] gids,
    566                                   int debugFlags, int mountExternal,
    567                                   int targetSdkVersion,
    568                                   String seInfo,
    569                                   String[] extraArgs)
    570                                   throws ZygoteStartFailedEx {
    571         synchronized(Process.class) {
    572             ArrayList<String> argsForZygote = new ArrayList<String>();
    573 
    574             // --runtime-init, --setuid=, --setgid=,
    575             // and --setgroups= must go first
    576             argsForZygote.add("--runtime-init");
    577             argsForZygote.add("--setuid=" + uid);
    578             argsForZygote.add("--setgid=" + gid);
    579             if ((debugFlags & Zygote.DEBUG_ENABLE_JNI_LOGGING) != 0) {
    580                 argsForZygote.add("--enable-jni-logging");
    581             }
    582             if ((debugFlags & Zygote.DEBUG_ENABLE_SAFEMODE) != 0) {
    583                 argsForZygote.add("--enable-safemode");
    584             }
    585             if ((debugFlags & Zygote.DEBUG_ENABLE_DEBUGGER) != 0) {
    586                 argsForZygote.add("--enable-debugger");
    587             }
    588             if ((debugFlags & Zygote.DEBUG_ENABLE_CHECKJNI) != 0) {
    589                 argsForZygote.add("--enable-checkjni");
    590             }
    591             if ((debugFlags & Zygote.DEBUG_ENABLE_ASSERT) != 0) {
    592                 argsForZygote.add("--enable-assert");
    593             }
    594             if (mountExternal == Zygote.MOUNT_EXTERNAL_MULTIUSER) {
    595                 argsForZygote.add("--mount-external-multiuser");
    596             } else if (mountExternal == Zygote.MOUNT_EXTERNAL_MULTIUSER_ALL) {
    597                 argsForZygote.add("--mount-external-multiuser-all");
    598             }
    599             argsForZygote.add("--target-sdk-version=" + targetSdkVersion);
    600 
    601             //TODO optionally enable debuger
    602             //argsForZygote.add("--enable-debugger");
    603 
    604             // --setgroups is a comma-separated list
    605             if (gids != null && gids.length > 0) {
    606                 StringBuilder sb = new StringBuilder();
    607                 sb.append("--setgroups=");
    608 
    609                 int sz = gids.length;
    610                 for (int i = 0; i < sz; i++) {
    611                     if (i != 0) {
    612                         sb.append(',');
    613                     }
    614                     sb.append(gids[i]);
    615                 }
    616 
    617                 argsForZygote.add(sb.toString());
    618             }
    619 
    620             if (niceName != null) {
    621                 argsForZygote.add("--nice-name=" + niceName);
    622             }
    623 
    624             if (seInfo != null) {
    625                 argsForZygote.add("--seinfo=" + seInfo);
    626             }
    627 
    628             argsForZygote.add(processClass);
    629 
    630             if (extraArgs != null) {
    631                 for (String arg : extraArgs) {
    632                     argsForZygote.add(arg);
    633                 }
    634             }
    635 
    636             return zygoteSendArgsAndGetResult(argsForZygote);
    637         }
    638     }
    639 
    640     /**
    641      * Returns elapsed milliseconds of the time this process has run.
    642      * @return  Returns the number of milliseconds this process has return.
    643      */
    644     public static final native long getElapsedCpuTime();
    645 
    646     /**
    647      * Returns the identifier of this process, which can be used with
    648      * {@link #killProcess} and {@link #sendSignal}.
    649      */
    650     public static final native int myPid();
    651 
    652     /**
    653      * Returns the identifier of the calling thread, which be used with
    654      * {@link #setThreadPriority(int, int)}.
    655      */
    656     public static final native int myTid();
    657 
    658     /**
    659      * Returns the identifier of this process's uid.  This is the kernel uid
    660      * that the process is running under, which is the identity of its
    661      * app-specific sandbox.  It is different from {@link #myUserHandle} in that
    662      * a uid identifies a specific app sandbox in a specific user.
    663      */
    664     public static final native int myUid();
    665 
    666     /**
    667      * Returns this process's user handle.  This is the
    668      * user the process is running under.  It is distinct from
    669      * {@link #myUid()} in that a particular user will have multiple
    670      * distinct apps running under it each with their own uid.
    671      */
    672     public static final UserHandle myUserHandle() {
    673         return new UserHandle(UserHandle.getUserId(myUid()));
    674     }
    675 
    676     /**
    677      * Returns whether the current process is in an isolated sandbox.
    678      * @hide
    679      */
    680     public static final boolean isIsolated() {
    681         int uid = UserHandle.getAppId(myUid());
    682         return uid >= FIRST_ISOLATED_UID && uid <= LAST_ISOLATED_UID;
    683     }
    684 
    685     /**
    686      * Returns the UID assigned to a particular user name, or -1 if there is
    687      * none.  If the given string consists of only numbers, it is converted
    688      * directly to a uid.
    689      */
    690     public static final native int getUidForName(String name);
    691 
    692     /**
    693      * Returns the GID assigned to a particular user name, or -1 if there is
    694      * none.  If the given string consists of only numbers, it is converted
    695      * directly to a gid.
    696      */
    697     public static final native int getGidForName(String name);
    698 
    699     /**
    700      * Returns a uid for a currently running process.
    701      * @param pid the process id
    702      * @return the uid of the process, or -1 if the process is not running.
    703      * @hide pending API council review
    704      */
    705     public static final int getUidForPid(int pid) {
    706         String[] procStatusLabels = { "Uid:" };
    707         long[] procStatusValues = new long[1];
    708         procStatusValues[0] = -1;
    709         Process.readProcLines("/proc/" + pid + "/status", procStatusLabels, procStatusValues);
    710         return (int) procStatusValues[0];
    711     }
    712 
    713     /**
    714      * Returns the parent process id for a currently running process.
    715      * @param pid the process id
    716      * @return the parent process id of the process, or -1 if the process is not running.
    717      * @hide
    718      */
    719     public static final int getParentPid(int pid) {
    720         String[] procStatusLabels = { "PPid:" };
    721         long[] procStatusValues = new long[1];
    722         procStatusValues[0] = -1;
    723         Process.readProcLines("/proc/" + pid + "/status", procStatusLabels, procStatusValues);
    724         return (int) procStatusValues[0];
    725     }
    726 
    727     /**
    728      * Returns the thread group leader id for a currently running thread.
    729      * @param tid the thread id
    730      * @return the thread group leader id of the thread, or -1 if the thread is not running.
    731      *         This is same as what getpid(2) would return if called by tid.
    732      * @hide
    733      */
    734     public static final int getThreadGroupLeader(int tid) {
    735         String[] procStatusLabels = { "Tgid:" };
    736         long[] procStatusValues = new long[1];
    737         procStatusValues[0] = -1;
    738         Process.readProcLines("/proc/" + tid + "/status", procStatusLabels, procStatusValues);
    739         return (int) procStatusValues[0];
    740     }
    741 
    742     /**
    743      * Set the priority of a thread, based on Linux priorities.
    744      *
    745      * @param tid The identifier of the thread/process to change.
    746      * @param priority A Linux priority level, from -20 for highest scheduling
    747      * priority to 19 for lowest scheduling priority.
    748      *
    749      * @throws IllegalArgumentException Throws IllegalArgumentException if
    750      * <var>tid</var> does not exist.
    751      * @throws SecurityException Throws SecurityException if your process does
    752      * not have permission to modify the given thread, or to use the given
    753      * priority.
    754      */
    755     public static final native void setThreadPriority(int tid, int priority)
    756             throws IllegalArgumentException, SecurityException;
    757 
    758     /**
    759      * Call with 'false' to cause future calls to {@link #setThreadPriority(int)} to
    760      * throw an exception if passed a background-level thread priority.  This is only
    761      * effective if the JNI layer is built with GUARD_THREAD_PRIORITY defined to 1.
    762      *
    763      * @hide
    764      */
    765     public static final native void setCanSelfBackground(boolean backgroundOk);
    766 
    767     /**
    768      * Sets the scheduling group for a thread.
    769      * @hide
    770      * @param tid The identifier of the thread to change.
    771      * @param group The target group for this thread from THREAD_GROUP_*.
    772      *
    773      * @throws IllegalArgumentException Throws IllegalArgumentException if
    774      * <var>tid</var> does not exist.
    775      * @throws SecurityException Throws SecurityException if your process does
    776      * not have permission to modify the given thread, or to use the given
    777      * priority.
    778      * If the thread is a thread group leader, that is it's gettid() == getpid(),
    779      * then the other threads in the same thread group are _not_ affected.
    780      */
    781     public static final native void setThreadGroup(int tid, int group)
    782             throws IllegalArgumentException, SecurityException;
    783 
    784     /**
    785      * Sets the scheduling group for a process and all child threads
    786      * @hide
    787      * @param pid The identifier of the process to change.
    788      * @param group The target group for this process from THREAD_GROUP_*.
    789      *
    790      * @throws IllegalArgumentException Throws IllegalArgumentException if
    791      * <var>tid</var> does not exist.
    792      * @throws SecurityException Throws SecurityException if your process does
    793      * not have permission to modify the given thread, or to use the given
    794      * priority.
    795      *
    796      * group == THREAD_GROUP_DEFAULT means to move all non-background priority
    797      * threads to the foreground scheduling group, but to leave background
    798      * priority threads alone.  group == THREAD_GROUP_BG_NONINTERACTIVE moves all
    799      * threads, regardless of priority, to the background scheduling group.
    800      * group == THREAD_GROUP_FOREGROUND is not allowed.
    801      */
    802     public static final native void setProcessGroup(int pid, int group)
    803             throws IllegalArgumentException, SecurityException;
    804 
    805     /**
    806      * Return the scheduling group of requested process.
    807      *
    808      * @hide
    809      */
    810     public static final native int getProcessGroup(int pid)
    811             throws IllegalArgumentException, SecurityException;
    812 
    813     /**
    814      * Set the priority of the calling thread, based on Linux priorities.  See
    815      * {@link #setThreadPriority(int, int)} for more information.
    816      *
    817      * @param priority A Linux priority level, from -20 for highest scheduling
    818      * priority to 19 for lowest scheduling priority.
    819      *
    820      * @throws IllegalArgumentException Throws IllegalArgumentException if
    821      * <var>tid</var> does not exist.
    822      * @throws SecurityException Throws SecurityException if your process does
    823      * not have permission to modify the given thread, or to use the given
    824      * priority.
    825      *
    826      * @see #setThreadPriority(int, int)
    827      */
    828     public static final native void setThreadPriority(int priority)
    829             throws IllegalArgumentException, SecurityException;
    830 
    831     /**
    832      * Return the current priority of a thread, based on Linux priorities.
    833      *
    834      * @param tid The identifier of the thread/process to change.
    835      *
    836      * @return Returns the current priority, as a Linux priority level,
    837      * from -20 for highest scheduling priority to 19 for lowest scheduling
    838      * priority.
    839      *
    840      * @throws IllegalArgumentException Throws IllegalArgumentException if
    841      * <var>tid</var> does not exist.
    842      */
    843     public static final native int getThreadPriority(int tid)
    844             throws IllegalArgumentException;
    845 
    846     /**
    847      * Set the scheduling policy and priority of a thread, based on Linux.
    848      *
    849      * @param tid The identifier of the thread/process to change.
    850      * @param policy A Linux scheduling policy such as SCHED_OTHER etc.
    851      * @param priority A Linux priority level in a range appropriate for the given policy.
    852      *
    853      * @throws IllegalArgumentException Throws IllegalArgumentException if
    854      * <var>tid</var> does not exist, or if <var>priority</var> is out of range for the policy.
    855      * @throws SecurityException Throws SecurityException if your process does
    856      * not have permission to modify the given thread, or to use the given
    857      * scheduling policy or priority.
    858      *
    859      * {@hide}
    860      */
    861     public static final native void setThreadScheduler(int tid, int policy, int priority)
    862             throws IllegalArgumentException;
    863 
    864     /**
    865      * Determine whether the current environment supports multiple processes.
    866      *
    867      * @return Returns true if the system can run in multiple processes, else
    868      * false if everything is running in a single process.
    869      *
    870      * @deprecated This method always returns true.  Do not use.
    871      */
    872     @Deprecated
    873     public static final boolean supportsProcesses() {
    874         return true;
    875     }
    876 
    877     /**
    878      * Set the out-of-memory badness adjustment for a process.
    879      *
    880      * @param pid The process identifier to set.
    881      * @param amt Adjustment value -- linux allows -16 to +15.
    882      *
    883      * @return Returns true if the underlying system supports this
    884      *         feature, else false.
    885      *
    886      * {@hide}
    887      */
    888     public static final native boolean setOomAdj(int pid, int amt);
    889 
    890     /**
    891      * Change this process's argv[0] parameter.  This can be useful to show
    892      * more descriptive information in things like the 'ps' command.
    893      *
    894      * @param text The new name of this process.
    895      *
    896      * {@hide}
    897      */
    898     public static final native void setArgV0(String text);
    899 
    900     /**
    901      * Kill the process with the given PID.
    902      * Note that, though this API allows us to request to
    903      * kill any process based on its PID, the kernel will
    904      * still impose standard restrictions on which PIDs you
    905      * are actually able to kill.  Typically this means only
    906      * the process running the caller's packages/application
    907      * and any additional processes created by that app; packages
    908      * sharing a common UID will also be able to kill each
    909      * other's processes.
    910      */
    911     public static final void killProcess(int pid) {
    912         sendSignal(pid, SIGNAL_KILL);
    913     }
    914 
    915     /** @hide */
    916     public static final native int setUid(int uid);
    917 
    918     /** @hide */
    919     public static final native int setGid(int uid);
    920 
    921     /**
    922      * Send a signal to the given process.
    923      *
    924      * @param pid The pid of the target process.
    925      * @param signal The signal to send.
    926      */
    927     public static final native void sendSignal(int pid, int signal);
    928 
    929     /**
    930      * @hide
    931      * Private impl for avoiding a log message...  DO NOT USE without doing
    932      * your own log, or the Android Illuminati will find you some night and
    933      * beat you up.
    934      */
    935     public static final void killProcessQuiet(int pid) {
    936         sendSignalQuiet(pid, SIGNAL_KILL);
    937     }
    938 
    939     /**
    940      * @hide
    941      * Private impl for avoiding a log message...  DO NOT USE without doing
    942      * your own log, or the Android Illuminati will find you some night and
    943      * beat you up.
    944      */
    945     public static final native void sendSignalQuiet(int pid, int signal);
    946 
    947     /** @hide */
    948     public static final native long getFreeMemory();
    949 
    950     /** @hide */
    951     public static final native long getTotalMemory();
    952 
    953     /** @hide */
    954     public static final native void readProcLines(String path,
    955             String[] reqFields, long[] outSizes);
    956 
    957     /** @hide */
    958     public static final native int[] getPids(String path, int[] lastArray);
    959 
    960     /** @hide */
    961     public static final int PROC_TERM_MASK = 0xff;
    962     /** @hide */
    963     public static final int PROC_ZERO_TERM = 0;
    964     /** @hide */
    965     public static final int PROC_SPACE_TERM = (int)' ';
    966     /** @hide */
    967     public static final int PROC_TAB_TERM = (int)'\t';
    968     /** @hide */
    969     public static final int PROC_COMBINE = 0x100;
    970     /** @hide */
    971     public static final int PROC_PARENS = 0x200;
    972     /** @hide */
    973     public static final int PROC_OUT_STRING = 0x1000;
    974     /** @hide */
    975     public static final int PROC_OUT_LONG = 0x2000;
    976     /** @hide */
    977     public static final int PROC_OUT_FLOAT = 0x4000;
    978 
    979     /** @hide */
    980     public static final native boolean readProcFile(String file, int[] format,
    981             String[] outStrings, long[] outLongs, float[] outFloats);
    982 
    983     /** @hide */
    984     public static final native boolean parseProcLine(byte[] buffer, int startIndex,
    985             int endIndex, int[] format, String[] outStrings, long[] outLongs, float[] outFloats);
    986 
    987     /** @hide */
    988     public static final native int[] getPidsForCommands(String[] cmds);
    989 
    990     /**
    991      * Gets the total Pss value for a given process, in bytes.
    992      *
    993      * @param pid the process to the Pss for
    994      * @return the total Pss value for the given process in bytes,
    995      *  or -1 if the value cannot be determined
    996      * @hide
    997      */
    998     public static final native long getPss(int pid);
    999 
   1000     /**
   1001      * Specifies the outcome of having started a process.
   1002      * @hide
   1003      */
   1004     public static final class ProcessStartResult {
   1005         /**
   1006          * The PID of the newly started process.
   1007          * Always >= 0.  (If the start failed, an exception will have been thrown instead.)
   1008          */
   1009         public int pid;
   1010 
   1011         /**
   1012          * True if the process was started with a wrapper attached.
   1013          */
   1014         public boolean usingWrapper;
   1015     }
   1016 }
   1017