content: /*
   * Copyright (C) 2006 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.os;
  
  import android.annotation.NonNull;
  import android.annotation.Nullable;
  import android.annotation.TestApi;
  import android.annotation.UnsupportedAppUsage;
  import android.system.Os;
  import android.system.OsConstants;
  import android.webkit.WebViewZygote;
  
  import dalvik.system.VMRuntime;
  
  /**
   * Tools for managing OS processes.
   */
  public class Process {
      private static final String LOG_TAG = "Process";
  
      /**
       * An invalid UID value.
       */
      public static final int INVALID_UID = -1;
  
      /**
       * Defines the root UID.
       */
      public static final int ROOT_UID = 0;
  
      /**
       * Defines the UID/GID under which system code runs.
       */
      public static final int SYSTEM_UID = 1000;
  
      /**
       * Defines the UID/GID under which the telephony code runs.
       */
      public static final int PHONE_UID = 1001;
  
      /**
       * Defines the UID/GID for the user shell.
       */
      public static final int SHELL_UID = 2000;
  
      /**
       * Defines the UID/GID for the log group.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int LOG_UID = 1007;
  
      /**
       * Defines the UID/GID for the WIFI supplicant process.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int WIFI_UID = 1010;
  
      /**
       * Defines the UID/GID for the mediaserver process.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int MEDIA_UID = 1013;
  
      /**
       * Defines the UID/GID for the DRM process.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int DRM_UID = 1019;
  
      /**
       * Defines the UID/GID for the group that controls VPN services.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int VPN_UID = 1016;
  
      /**
       * Defines the UID/GID for keystore.
       * @hide
       */
      public static final int KEYSTORE_UID = 1017;
  
      /**
       * Defines the UID/GID for the NFC service process.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int NFC_UID = 1027;
  
      /**
       * Defines the UID/GID for the clatd process.
       * @hide
       * */
      public static final int CLAT_UID = 1029;
  
      /**
       * Defines the UID/GID for the Bluetooth service process.
       */
      public static final int BLUETOOTH_UID = 1002;
  
      /**
       * Defines the GID for the group that allows write access to the internal media storage.
       * @hide
       */
      public static final int MEDIA_RW_GID = 1023;
  
      /**
       * Access to installed package details
       * @hide
       */
      public static final int PACKAGE_INFO_GID = 1032;
  
      /**
       * Defines the UID/GID for the shared RELRO file updater process.
       * @hide
       */
      public static final int SHARED_RELRO_UID = 1037;
  
      /**
       * Defines the UID/GID for the audioserver process.
       * @hide
       */
      public static final int AUDIOSERVER_UID = 1041;
  
      /**
       * Defines the UID/GID for the cameraserver process
       * @hide
       */
      public static final int CAMERASERVER_UID = 1047;
  
      /**
       * Defines the UID/GID for the tethering DNS resolver (currently dnsmasq).
       * @hide
       */
      public static final int DNS_TETHER_UID = 1052;
  
      /**
       * Defines the UID/GID for the WebView zygote process.
       * @hide
       */
      public static final int WEBVIEW_ZYGOTE_UID = 1053;
  
      /**
       * Defines the UID used for resource tracking for OTA updates.
       * @hide
       */
      public static final int OTA_UPDATE_UID = 1061;
  
      /**
       * Defines the UID used for incidentd.
       * @hide
       */
      public static final int INCIDENTD_UID = 1067;
  
      /**
       * Defines the UID/GID for the Secure Element service process.
       * @hide
       */
      public static final int SE_UID = 1068;
  
      /**
       * Defines the UID/GID for the NetworkStack app.
       * @hide
       */
      public static final int NETWORK_STACK_UID = 1073;
  
      /** {@hide} */
      public static final int NOBODY_UID = 9999;
  
      /**
       * Defines the start of a range of UIDs (and GIDs), going from this
       * number to {@link #LAST_APPLICATION_UID} that are reserved for assigning
       * to applications.
       */
      public static final int FIRST_APPLICATION_UID = 10000;
  
      /**
       * Last of application-specific UIDs starting at
       * {@link #FIRST_APPLICATION_UID}.
       */
      public static final int LAST_APPLICATION_UID = 19999;
  
      /**
       * First uid used for fully isolated sandboxed processes spawned from an app zygote
       * @hide
       */
      @TestApi
      public static final int FIRST_APP_ZYGOTE_ISOLATED_UID = 90000;
  
      /**
       * Number of UIDs we allocate per application zygote
       * @hide
       */
      @TestApi
      public static final int NUM_UIDS_PER_APP_ZYGOTE = 100;
  
      /**
       * Last uid used for fully isolated sandboxed processes spawned from an app zygote
       * @hide
       */
      @TestApi
      public static final int LAST_APP_ZYGOTE_ISOLATED_UID = 98999;
  
      /**
       * First uid used for fully isolated sandboxed processes (with no permissions of their own)
       * @hide
       */
      @TestApi
      public static final int FIRST_ISOLATED_UID = 99000;
  
      /**
       * Last uid used for fully isolated sandboxed processes (with no permissions of their own)
       * @hide
       */
      @TestApi
      public static final int LAST_ISOLATED_UID = 99999;
  
      /**
       * Defines the gid shared by all applications running under the same profile.
       * @hide
       */
      public static final int SHARED_USER_GID = 9997;
  
      /**
       * First gid for applications to share resources. Used when forward-locking
       * is enabled but all UserHandles need to be able to read the resources.
       * @hide
       */
      public static final int FIRST_SHARED_APPLICATION_GID = 50000;
  
      /**
       * Last gid for applications to share resources. Used when forward-locking
       * is enabled but all UserHandles need to be able to read the resources.
       * @hide
       */
      public static final int LAST_SHARED_APPLICATION_GID = 59999;
  
      /** {@hide} */
      public static final int FIRST_APPLICATION_CACHE_GID = 20000;
      /** {@hide} */
      public static final int LAST_APPLICATION_CACHE_GID = 29999;
  
      /**
       * Standard priority of application threads.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_DEFAULT = 0;
  
      /*
       * ***************************************
       * ** Keep in sync with utils/threads.h **
       * ***************************************
       */
      
      /**
       * Lowest available thread priority.  Only for those who really, really
       * don't want to run if anything else is happening.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_LOWEST = 19;
      
      /**
       * Standard priority background threads.  This gives your thread a slightly
       * lower than normal priority, so that it will have less chance of impacting
       * the responsiveness of the user interface.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_BACKGROUND = 10;
      
      /**
       * Standard priority of threads that are currently running a user interface
       * that the user is interacting with.  Applications can not normally
       * change to this priority; the system will automatically adjust your
       * application threads as the user moves through the UI.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_FOREGROUND = -2;
      
      /**
       * Standard priority of system display threads, involved in updating
       * the user interface.  Applications can not
       * normally change to this priority.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_DISPLAY = -4;
      
      /**
       * Standard priority of the most important display threads, for compositing
       * the screen and retrieving input events.  Applications can not normally
       * change to this priority.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_URGENT_DISPLAY = -8;
  
      /**
       * Standard priority of video threads.  Applications can not normally
       * change to this priority.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_VIDEO = -10;
  
      /**
       * Standard priority of audio threads.  Applications can not normally
       * change to this priority.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_AUDIO = -16;
  
      /**
       * Standard priority of the most important audio threads.
       * Applications can not normally change to this priority.
       * Use with {@link #setThreadPriority(int)} and
       * {@link #setThreadPriority(int, int)}, <b>not</b> with the normal
       * {@link java.lang.Thread} class.
       */
      public static final int THREAD_PRIORITY_URGENT_AUDIO = -19;
  
      /**
       * Minimum increment to make a priority more favorable.
       */
      public static final int THREAD_PRIORITY_MORE_FAVORABLE = -1;
  
      /**
       * Minimum increment to make a priority less favorable.
       */
      public static final int THREAD_PRIORITY_LESS_FAVORABLE = +1;
  
      /**
       * Default scheduling policy
       * @hide
       */
      public static final int SCHED_OTHER = 0;
  
      /**
       * First-In First-Out scheduling policy
       * @hide
       */
      public static final int SCHED_FIFO = 1;
  
      /**
       * Round-Robin scheduling policy
       * @hide
       */
      public static final int SCHED_RR = 2;
  
      /**
       * Batch scheduling policy
       * @hide
       */
      public static final int SCHED_BATCH = 3;
  
      /**
       * Idle scheduling policy
       * @hide
       */
      public static final int SCHED_IDLE = 5;
  
      /**
       * Reset scheduler choice on fork.
       * @hide
       */
      public static final int SCHED_RESET_ON_FORK = 0x40000000;
  
      // Keep in sync with SP_* constants of enum type SchedPolicy
      // declared in system/core/include/cutils/sched_policy.h,
      // except THREAD_GROUP_DEFAULT does not correspond to any SP_* value.
  
      /**
       * Default thread group -
       * has meaning with setProcessGroup() only, cannot be used with setThreadGroup().
       * When used with setProcessGroup(), the group of each thread in the process
       * is conditionally changed based on that thread's current priority, as follows:
       * threads with priority numerically less than THREAD_PRIORITY_BACKGROUND
       * are moved to foreground thread group.  All other threads are left unchanged.
       * @hide
       */
      public static final int THREAD_GROUP_DEFAULT = -1;
  
      /**
       * Background thread group - All threads in
       * this group are scheduled with a reduced share of the CPU.
       * Value is same as constant SP_BACKGROUND of enum SchedPolicy.
       * FIXME rename to THREAD_GROUP_BACKGROUND.
       * @hide
       */
      public static final int THREAD_GROUP_BG_NONINTERACTIVE = 0;
  
      /**
       * Foreground thread group - All threads in
       * this group are scheduled with a normal share of the CPU.
       * Value is same as constant SP_FOREGROUND of enum SchedPolicy.
       * Not used at this level.
       * @hide
       **/
      private static final int THREAD_GROUP_FOREGROUND = 1;
  
      /**
       * System thread group.
       * @hide
       **/
      public static final int THREAD_GROUP_SYSTEM = 2;
  
      /**
       * Application audio thread group.
       * @hide
       **/
      public static final int THREAD_GROUP_AUDIO_APP = 3;
  
      /**
       * System audio thread group.
       * @hide
       **/
      public static final int THREAD_GROUP_AUDIO_SYS = 4;
  
      /**
       * Thread group for top foreground app.
       * @hide
       **/
      public static final int THREAD_GROUP_TOP_APP = 5;
  
      /**
       * Thread group for RT app.
       * @hide
       **/
      public static final int THREAD_GROUP_RT_APP = 6;
  
      /**
       * Thread group for bound foreground services that should
       * have additional CPU restrictions during screen off
       * @hide
       **/
      public static final int THREAD_GROUP_RESTRICTED = 7;
  
      public static final int SIGNAL_QUIT = 3;
      public static final int SIGNAL_KILL = 9;
      public static final int SIGNAL_USR1 = 10;
  
      private static long sStartElapsedRealtime;
      private static long sStartUptimeMillis;
  
      /**
       * State associated with the zygote process.
       * @hide
       */
      public static final ZygoteProcess ZYGOTE_PROCESS = new ZygoteProcess();
  
      /**
       * Start a new process.
       * 
       * <p>If processes are enabled, a new process is created and the
       * static main() function of a <var>processClass</var> is executed there.
       * The process will continue running after this function returns.
       * 
       * <p>If processes are not enabled, a new thread in the caller's
       * process is created and main() of <var>processClass</var> called there.
       * 
       * <p>The niceName parameter, if not an empty string, is a custom name to
       * give to the process instead of using processClass.  This allows you to
       * make easily identifyable processes even if you are using the same base
       * <var>processClass</var> to start them.
       * 
       * When invokeWith is not null, the process will be started as a fresh app
       * and not a zygote fork. Note that this is only allowed for uid 0 or when
       * runtimeFlags contains DEBUG_ENABLE_DEBUGGER.
       *
       * @param processClass The class to use as the process's main entry
       *                     point.
       * @param niceName A more readable name to use for the process.
       * @param uid The user-id under which the process will run.
       * @param gid The group-id under which the process will run.
       * @param gids Additional group-ids associated with the process.
       * @param runtimeFlags Additional flags for the runtime.
       * @param targetSdkVersion The target SDK version for the app.
       * @param seInfo null-ok SELinux information for the new process.
       * @param abi non-null the ABI this app should be started with.
       * @param instructionSet null-ok the instruction set to use.
       * @param appDataDir null-ok the data directory of the app.
       * @param invokeWith null-ok the command to invoke with.
       * @param packageName null-ok the name of the package this process belongs to.
       *
       * @param zygoteArgs Additional arguments to supply to the zygote process.
       * @return An object that describes the result of the attempt to start the process.
       * @throws RuntimeException on fatal start failure
       * 
       * {@hide}
       */
      public static ProcessStartResult start(@NonNull final String processClass,
                                             @Nullable final String niceName,
                                             int uid, int gid, @Nullable int[] gids,
                                             int runtimeFlags,
                                             int mountExternal,
                                             int targetSdkVersion,
                                             @Nullable String seInfo,
                                             @NonNull String abi,
                                             @Nullable String instructionSet,
                                             @Nullable String appDataDir,
                                             @Nullable String invokeWith,
                                             @Nullable String packageName,
                                             @Nullable String[] zygoteArgs) {
          return ZYGOTE_PROCESS.start(processClass, niceName, uid, gid, gids,
                      runtimeFlags, mountExternal, targetSdkVersion, seInfo,
                      abi, instructionSet, appDataDir, invokeWith, packageName,
                      /*useUsapPool=*/ true, zygoteArgs);
      }
  
      /** @hide */
      public static ProcessStartResult startWebView(@NonNull final String processClass,
                                                    @Nullable final String niceName,
                                                    int uid, int gid, @Nullable int[] gids,
                                                    int runtimeFlags,
                                                    int mountExternal,
                                                    int targetSdkVersion,
                                                    @Nullable String seInfo,
                                                    @NonNull String abi,
                                                    @Nullable String instructionSet,
                                                    @Nullable String appDataDir,
                                                    @Nullable String invokeWith,
                                                    @Nullable String packageName,
                                                    @Nullable String[] zygoteArgs) {
          return WebViewZygote.getProcess().start(processClass, niceName, uid, gid, gids,
                      runtimeFlags, mountExternal, targetSdkVersion, seInfo,
                      abi, instructionSet, appDataDir, invokeWith, packageName,
                      /*useUsapPool=*/ false, zygoteArgs);
      }
  
      /**
       * Returns elapsed milliseconds of the time this process has run.
       * @return  Returns the number of milliseconds this process has return.
       */
      public static final native long getElapsedCpuTime();
  
      /**
       * Return the {@link SystemClock#elapsedRealtime()} at which this process was started.
       */
      public static final long getStartElapsedRealtime() {
          return sStartElapsedRealtime;
      }
  
      /**
       * Return the {@link SystemClock#uptimeMillis()} at which this process was started.
       */
      public static final long getStartUptimeMillis() {
          return sStartUptimeMillis;
      }
  
      /** @hide */
      public static final void setStartTimes(long elapsedRealtime, long uptimeMillis) {
          sStartElapsedRealtime = elapsedRealtime;
          sStartUptimeMillis = uptimeMillis;
      }
  
      /**
       * Returns true if the current process is a 64-bit runtime.
       */
      public static final boolean is64Bit() {
          return VMRuntime.getRuntime().is64Bit();
      }
  
      /**
       * Returns the identifier of this process, which can be used with
       * {@link #killProcess} and {@link #sendSignal}.
       */
      public static final int myPid() {
          return Os.getpid();
      }
  
      /**
       * Returns the identifier of this process' parent.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int myPpid() {
          return Os.getppid();
      }
  
      /**
       * Returns the identifier of the calling thread, which be used with
       * {@link #setThreadPriority(int, int)}.
       */
      public static final int myTid() {
          return Os.gettid();
      }
  
      /**
       * Returns the identifier of this process's uid.  This is the kernel uid
       * that the process is running under, which is the identity of its
       * app-specific sandbox.  It is different from {@link #myUserHandle} in that
       * a uid identifies a specific app sandbox in a specific user.
       */
      public static final int myUid() {
          return Os.getuid();
      }
  
      /**
       * Returns this process's user handle.  This is the
       * user the process is running under.  It is distinct from
       * {@link #myUid()} in that a particular user will have multiple
       * distinct apps running under it each with their own uid.
       */
      public static UserHandle myUserHandle() {
          return UserHandle.of(UserHandle.getUserId(myUid()));
      }
  
      /**
       * Returns whether the given uid belongs to a system core component or not.
       * @hide
       */
      public static boolean isCoreUid(int uid) {
          return UserHandle.isCore(uid);
      }
  
      /**
       * Returns whether the given uid belongs to an application.
       * @param uid A kernel uid.
       * @return Whether the uid corresponds to an application sandbox running in
       *     a specific user.
       */
      public static boolean isApplicationUid(int uid) {
          return UserHandle.isApp(uid);
      }
  
      /**
       * Returns whether the current process is in an isolated sandbox.
       */
      public static final boolean isIsolated() {
          return isIsolated(myUid());
      }
  
      /** {@hide} */
      @UnsupportedAppUsage
      public static final boolean isIsolated(int uid) {
          uid = UserHandle.getAppId(uid);
          return (uid >= FIRST_ISOLATED_UID && uid <= LAST_ISOLATED_UID)
                  || (uid >= FIRST_APP_ZYGOTE_ISOLATED_UID && uid <= LAST_APP_ZYGOTE_ISOLATED_UID);
      }
  
      /**
       * Returns the UID assigned to a particular user name, or -1 if there is
       * none.  If the given string consists of only numbers, it is converted
       * directly to a uid.
       */
      public static final native int getUidForName(String name);
      
      /**
       * Returns the GID assigned to a particular user name, or -1 if there is
       * none.  If the given string consists of only numbers, it is converted
       * directly to a gid.
       */
      public static final native int getGidForName(String name);
  
      /**
       * Returns a uid for a currently running process.
       * @param pid the process id
       * @return the uid of the process, or -1 if the process is not running.
       * @hide pending API council review
       */
      @UnsupportedAppUsage
      public static final int getUidForPid(int pid) {
          String[] procStatusLabels = { "Uid:" };
          long[] procStatusValues = new long[1];
          procStatusValues[0] = -1;
          Process.readProcLines("/proc/" + pid + "/status", procStatusLabels, procStatusValues);
          return (int) procStatusValues[0];
      }
  
      /**
       * Returns the parent process id for a currently running process.
       * @param pid the process id
       * @return the parent process id of the process, or -1 if the process is not running.
       * @hide
       */
      @UnsupportedAppUsage
      public static final int getParentPid(int pid) {
          String[] procStatusLabels = { "PPid:" };
          long[] procStatusValues = new long[1];
          procStatusValues[0] = -1;
          Process.readProcLines("/proc/" + pid + "/status", procStatusLabels, procStatusValues);
          return (int) procStatusValues[0];
      }
  
      /**
       * Returns the thread group leader id for a currently running thread.
       * @param tid the thread id
       * @return the thread group leader id of the thread, or -1 if the thread is not running.
       *         This is same as what getpid(2) would return if called by tid.
       * @hide
       */
      public static final int getThreadGroupLeader(int tid) {
          String[] procStatusLabels = { "Tgid:" };
          long[] procStatusValues = new long[1];
          procStatusValues[0] = -1;
          Process.readProcLines("/proc/" + tid + "/status", procStatusLabels, procStatusValues);
          return (int) procStatusValues[0];
      }
  
      /**
       * Set the priority of a thread, based on Linux priorities.
       * 
       * @param tid The identifier of the thread/process to change.
       * @param priority A Linux priority level, from -20 for highest scheduling
       * priority to 19 for lowest scheduling priority.
       * 
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist.
       * @throws SecurityException Throws SecurityException if your process does
       * not have permission to modify the given thread, or to use the given
       * priority.
       */
      public static final native void setThreadPriority(int tid, int priority)
              throws IllegalArgumentException, SecurityException;
  
      /**
       * Call with 'false' to cause future calls to {@link #setThreadPriority(int)} to
       * throw an exception if passed a background-level thread priority.  This is only
       * effective if the JNI layer is built with GUARD_THREAD_PRIORITY defined to 1.
       *
       * @hide
       */
      public static final native void setCanSelfBackground(boolean backgroundOk);
  
      /**
       * Sets the scheduling group for a thread.
       * @hide
       * @param tid The identifier of the thread to change.
       * @param group The target group for this thread from THREAD_GROUP_*.
       *
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist.
       * @throws SecurityException Throws SecurityException if your process does
       * not have permission to modify the given thread, or to use the given
       * priority.
       * If the thread is a thread group leader, that is it's gettid() == getpid(),
       * then the other threads in the same thread group are _not_ affected.
       *
       * Does not set cpuset for some historical reason, just calls
       * libcutils::set_sched_policy().
       */
      public static final native void setThreadGroup(int tid, int group)
              throws IllegalArgumentException, SecurityException;
  
      /**
       * Sets the scheduling group and the corresponding cpuset group
       * @hide
       * @param tid The identifier of the thread to change.
       * @param group The target group for this thread from THREAD_GROUP_*.
       *
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist.
       * @throws SecurityException Throws SecurityException if your process does
       * not have permission to modify the given thread, or to use the given
       * priority.
       */
      public static final native void setThreadGroupAndCpuset(int tid, int group)
              throws IllegalArgumentException, SecurityException;
  
      /**
       * Sets the scheduling group for a process and all child threads
       * @hide
       * @param pid The identifier of the process to change.
       * @param group The target group for this process from THREAD_GROUP_*.
       * 
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist.
       * @throws SecurityException Throws SecurityException if your process does
       * not have permission to modify the given thread, or to use the given
       * priority.
       *
       * group == THREAD_GROUP_DEFAULT means to move all non-background priority
       * threads to the foreground scheduling group, but to leave background
       * priority threads alone.  group == THREAD_GROUP_BG_NONINTERACTIVE moves all
       * threads, regardless of priority, to the background scheduling group.
       * group == THREAD_GROUP_FOREGROUND is not allowed.
       *
       * Always sets cpusets.
       */
      @UnsupportedAppUsage
      public static final native void setProcessGroup(int pid, int group)
              throws IllegalArgumentException, SecurityException;
  
      /**
       * Return the scheduling group of requested process.
       *
       * @hide
       */
      public static final native int getProcessGroup(int pid)
              throws IllegalArgumentException, SecurityException;
  
      /**
       * On some devices, the foreground process may have one or more CPU
       * cores exclusively reserved for it. This method can be used to
       * retrieve which cores that are (if any), so the calling process
       * can then use sched_setaffinity() to lock a thread to these cores.
       * Note that the calling process must currently be running in the
       * foreground for this method to return any cores.
       *
       * The CPU core(s) exclusively reserved for the foreground process will
       * stay reserved for as long as the process stays in the foreground.
       *
       * As soon as a process leaves the foreground, those CPU cores will
       * no longer be reserved for it, and will most likely be reserved for
       * the new foreground process. It's not necessary to change the affinity
       * of your process when it leaves the foreground (if you had previously
       * set it to use a reserved core); the OS will automatically take care
       * of resetting the affinity at that point.
       *
       * @return an array of integers, indicating the CPU cores exclusively
       * reserved for this process. The array will have length zero if no
       * CPU cores are exclusively reserved for this process at this point
       * in time.
       */
      public static final native int[] getExclusiveCores();
  
      /**
       * Set the priority of the calling thread, based on Linux priorities.  See
       * {@link #setThreadPriority(int, int)} for more information.
       * 
       * @param priority A Linux priority level, from -20 for highest scheduling
       * priority to 19 for lowest scheduling priority.
       * 
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist.
       * @throws SecurityException Throws SecurityException if your process does
       * not have permission to modify the given thread, or to use the given
       * priority.
       * 
       * @see #setThreadPriority(int, int)
       */
      public static final native void setThreadPriority(int priority)
              throws IllegalArgumentException, SecurityException;
      
      /**
       * Return the current priority of a thread, based on Linux priorities.
       * 
       * @param tid The identifier of the thread/process. If tid equals zero, the priority of the
       * calling process/thread will be returned.
       * 
       * @return Returns the current priority, as a Linux priority level,
       * from -20 for highest scheduling priority to 19 for lowest scheduling
       * priority.
       * 
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist.
       */
      public static final native int getThreadPriority(int tid)
              throws IllegalArgumentException;
      
      /**
       * Return the current scheduling policy of a thread, based on Linux.
       *
       * @param tid The identifier of the thread/process to get the scheduling policy.
       *
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist, or if <var>priority</var> is out of range for the policy.
       * @throws SecurityException Throws SecurityException if your process does
       * not have permission to modify the given thread, or to use the given
       * scheduling policy or priority.
       *
       * {@hide}
       */
      
      @TestApi
      public static final native int getThreadScheduler(int tid)
              throws IllegalArgumentException;
  
      /**
       * Set the scheduling policy and priority of a thread, based on Linux.
       *
       * @param tid The identifier of the thread/process to change.
       * @param policy A Linux scheduling policy such as SCHED_OTHER etc.
       * @param priority A Linux priority level in a range appropriate for the given policy.
       *
       * @throws IllegalArgumentException Throws IllegalArgumentException if
       * <var>tid</var> does not exist, or if <var>priority</var> is out of range for the policy.
       * @throws SecurityException Throws SecurityException if your process does
       * not have permission to modify the given thread, or to use the given
       * scheduling policy or priority.
       *
       * {@hide}
       */
  
      public static final native void setThreadScheduler(int tid, int policy, int priority)
              throws IllegalArgumentException;
  
      /**
       * Determine whether the current environment supports multiple processes.
       * 
       * @return Returns true if the system can run in multiple processes, else
       * false if everything is running in a single process.
       *
       * @deprecated This method always returns true.  Do not use.
       */
      @Deprecated
      public static final boolean supportsProcesses() {
          return true;
      }
  
      /**
       * Adjust the swappiness level for a process.
       *
       * @param pid The process identifier to set.
       * @param is_increased Whether swappiness should be increased or default.
       *
       * @return Returns true if the underlying system supports this
       *         feature, else false.
       *
       * {@hide}
       */
      public static final native boolean setSwappiness(int pid, boolean is_increased);
  
      /**
       * Change this process's argv[0] parameter.  This can be useful to show
       * more descriptive information in things like the 'ps' command.
       * 
       * @param text The new name of this process.
       * 
       * {@hide}
       */
      @UnsupportedAppUsage
      public static final native void setArgV0(String text);
  
      /**
       * Kill the process with the given PID.
       * Note that, though this API allows us to request to
       * kill any process based on its PID, the kernel will
       * still impose standard restrictions on which PIDs you
       * are actually able to kill.  Typically this means only
       * the process running the caller's packages/application
       * and any additional processes created by that app; packages
       * sharing a common UID will also be able to kill each
       * other's processes.
       */
      public static final void killProcess(int pid) {
          sendSignal(pid, SIGNAL_KILL);
      }
  
      /** @hide */
      public static final native int setUid(int uid);
  
      /** @hide */
      public static final native int setGid(int uid);
  
      /**
       * Send a signal to the given process.
       * 
       * @param pid The pid of the target process.
       * @param signal The signal to send.
       */
      public static final native void sendSignal(int pid, int signal);
      
      /**
       * @hide
       * Private impl for avoiding a log message...  DO NOT USE without doing
       * your own log, or the Android Illuminati will find you some night and
       * beat you up.
       */
      public static final void killProcessQuiet(int pid) {
          sendSignalQuiet(pid, SIGNAL_KILL);
      }
  
      /**
       * @hide
       * Private impl for avoiding a log message...  DO NOT USE without doing
       * your own log, or the Android Illuminati will find you some night and
       * beat you up.
       */
      public static final native void sendSignalQuiet(int pid, int signal);
      
      /** @hide */
      @UnsupportedAppUsage
      public static final native long getFreeMemory();
      
      /** @hide */
      @UnsupportedAppUsage
      public static final native long getTotalMemory();
      
      /** @hide */
      @UnsupportedAppUsage
      public static final native void readProcLines(String path,
              String[] reqFields, long[] outSizes);
      
      /** @hide */
      @UnsupportedAppUsage
      public static final native int[] getPids(String path, int[] lastArray);
      
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_TERM_MASK = 0xff;
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_ZERO_TERM = 0;
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_SPACE_TERM = (int)' ';
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_TAB_TERM = (int)'\t';
      /** @hide */
      public static final int PROC_NEWLINE_TERM = (int) '\n';
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_COMBINE = 0x100;
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_PARENS = 0x200;
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_QUOTES = 0x400;
      /** @hide */
      public static final int PROC_CHAR = 0x800;
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_OUT_STRING = 0x1000;
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_OUT_LONG = 0x2000;
      /** @hide */
      @UnsupportedAppUsage
      public static final int PROC_OUT_FLOAT = 0x4000;
  
      /**
       * Read and parse a {@code proc} file in the given format.
       *
       * <p>The format is a list of integers, where every integer describes a variable in the file. It
       * specifies how the variable is syntactically terminated (e.g. {@link Process#PROC_SPACE_TERM},
       * {@link Process#PROC_TAB_TERM}, {@link Process#PROC_ZERO_TERM}, {@link
       * Process#PROC_NEWLINE_TERM}).
       *
       * <p>If the variable should be parsed and returned to the caller, the termination type should
       * be binary OR'd with the type of output (e.g. {@link Process#PROC_OUT_STRING}, {@link
       * Process#PROC_OUT_LONG}, {@link Process#PROC_OUT_FLOAT}.
       *
       * <p>If the variable is wrapped in quotation marks it should be binary OR'd with {@link
       * Process#PROC_QUOTES}. If the variable is wrapped in parentheses it should be binary OR'd with
       * {@link Process#PROC_PARENS}.
       *
       * <p>If the variable is not formatted as a string and should be cast directly from characters
       * to a long, the {@link Process#PROC_CHAR} integer should be binary OR'd.
       *
       * <p>If the terminating character can be repeated, the {@link Process#PROC_COMBINE} integer
       * should be binary OR'd.
       *
       * @param file the path of the {@code proc} file to read
       * @param format the format of the file
       * @param outStrings the parsed {@code String}s from the file
       * @param outLongs the parsed {@code long}s from the file
       * @param outFloats the parsed {@code float}s from the file
       * @hide
       */
      @UnsupportedAppUsage
      public static final native boolean readProcFile(String file, int[] format,
              String[] outStrings, long[] outLongs, float[] outFloats);
  
      /** @hide */
      @UnsupportedAppUsage
      public static final native boolean parseProcLine(byte[] buffer, int startIndex, 
              int endIndex, int[] format, String[] outStrings, long[] outLongs, float[] outFloats);
  
      /** @hide */
      @UnsupportedAppUsage
      public static final native int[] getPidsForCommands(String[] cmds);
  
      /**
       * Gets the total Pss value for a given process, in bytes.
       * 
       * @param pid the process to the Pss for
       * @return the total Pss value for the given process in bytes,
       *  or -1 if the value cannot be determined 
       * @hide
       */
      @UnsupportedAppUsage
      public static final native long getPss(int pid);
  
      /** @hide */
      public static final native long[] getRss(int pid);
  
      /**
       * Specifies the outcome of having started a process.
       * @hide
       */
      public static final class ProcessStartResult {
          /**
           * The PID of the newly started process.
           * Always >= 0.  (If the start failed, an exception will have been thrown instead.)
           */
          public int pid;
  
          /**
           * True if the process was started with a wrapper attached.
           */
          public boolean usingWrapper;
      }
  
      /**
       * Kill all processes in a process group started for the given
       * pid.
       * @hide
       */
      public static final native int killProcessGroup(int uid, int pid);
  
      /**
       * Remove all process groups.  Expected to be called when ActivityManager
       * is restarted.
       * @hide
       */
      public static final native void removeAllProcessGroups();
  
      /**
       * Check to see if a thread belongs to a given process. This may require
       * more permissions than apps generally have.
       * @return true if this thread belongs to a process
       * @hide
       */
      public static final boolean isThreadInProcess(int tid, int pid) {
          StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
          try {
              if (Os.access("/proc/" + tid + "/task/" + pid, OsConstants.F_OK)) {
                  return true;
              } else {
                  return false;
              }
          } catch (Exception e) {
              return false;
          } finally {
              StrictMode.setThreadPolicy(oldPolicy);
          }
  
      }
  }
  