最近想寻找什么方法能够彻底的关闭别人的app！
这听起来就很流氓，居然是关闭别人的，而且还要是关闭 前台进程（Foreground process)，这想法真大胆。查了下目前的资料，
类似各种xx大师，管家的一键加速功能，这种根据各个进程adj评分去关闭方案，似乎对于前台进程是鞭长莫及。
按照我们熟悉的forceStopPackage 这个是AM的隐藏方法，实际上由于签名，uid等限制条件，并不能真的关闭第三方，别人的程序。另外AM还有别的方法听起来像可以关闭别人进程的，如
killBackgroundProcesses，removeTask等。Process.killProcess()
在process这个类里面，由几个方法可以调用去关闭，其中有一个的注释很有意思，打算贴出来。/** * @hide * Private impl for avoiding a log message... DO NOT USE without doing * your own log, or the Android Illuminati （安卓光明会）will find you some night and beat you up. * 这段注释很调皮😝，特拿出来哈 */ public static final void killProcessQuiet(int pid) { sendSignalQuiet(pid, SIGNAL_KILL); } public static final native void sendSignalQuiet(int pid, int signal);
对于上面的所有，这篇文章主要记录forceStopPackage（）背后执行的内容，别的方法之后再考虑写。
起航
api:23
AM.forceStopPackage
/**
* @see #forceStopPackageAsUser(String, int)
* @hide
*/
public void forceStopPackage(String packageName) {
forceStopPackageAsUser(packageName, UserHandle.myUserId());
}
我们调用这个方法，背后是去掉哟功能asUser这个。前者参数为我们想关闭的包名，后者是当前调用者的uid。
/**
* Have the system perform a force stop of everything associated with
* the given application package. All processes that share its uid
* will be killed, all services it has running stopped, all activities
* removed, etc. In addition, a {@link Intent#ACTION_PACKAGE_RESTARTED}
* broadcast will be sent, so that any of its registered alarms can
* be stopped, notifications removed, etc.
* 看注释，我们知道这个是非常强效的关闭第三方app，很彻底的，包括他的service，闹钟等都关闭。对应我们需要声明FORCE_STOP_PACKAGES这个权限。
*
* <p>You must hold the permission
* {@link android.Manifest.permission#FORCE_STOP_PACKAGES} to be able to
* call this method.
*
* @param packageName The name of the package to be stopped.
* @param userId The user for which the running package is to be stopped.
*
* @hide This is not available to third party applications due to
* it allowing them to break other applications by stopping their
* services, removing their alarms, etc.
*/
public void forceStopPackageAsUser(String packageName, int userId) {
try {
ActivityManagerNative.getDefault().forceStopPackage(packageName, userId);
//然后这个方法实际是跑到ams去调用的
} catch (RemoteException e) {
}
}
ams.forceStopPackage()
@Override
public void forceStopPackage(final String packageName, int userId) {
//开头会检验下你是否声明了FORCE_STOP_PACKAGES权限，没有就送你一个se的异常
//整个检验不是我们这次关注的核心就不细说了。
//结论就是跑去pms.checkUidPermission(permName,uid)
if (checkCallingPermission(
android.Manifest.permission.FORCE_STOP_PACKAGES)
!= PackageManager.PERMISSION_GRANTED) {
String msg = "Permission Denial: forceStopPackage() from pid="
+ Binder.getCallingPid()
+ ", uid=" + Binder.getCallingUid()
+ " requires " + android.Manifest.permission.FORCE_STOP_PACKAGES;
throw new SecurityException(msg);
}
//准备参数
final int callingPid = Binder.getCallingPid();
userId = handleIncomingUser(callingPid, Binder.getCallingUid(),
userId, true, ALLOW_FULL_ONLY, "forceStopPackage", null);
long callingId = Binder.clearCallingIdentity();
try {
IPackageManager pm = AppGlobals.getPackageManager();
synchronized(this) {
int[] users = userId == UserHandle.USER_ALL
? getUsersLocked() : new int[] { userId };
// /** @hide A user id to indicate all users on the device */
// public static final int USER_ALL = -1;
//这句看起来让人觉得云里雾里，作为固定正数值-1,好像这个三元判断优点不对劲啊。
for (int user : users) {
int pkgUid = -1;
pkgUid = pm.getPackageUid(packageName, user);
if (pkgUid == -1) {
Slog.w(TAG, "Invalid packageName: " + packageName);
continue;
}
//然后就是告诉pms去表记包为停止状态，
pm.setPackageStoppedState(packageName, true, user);
if (isUserRunningLocked(user, false)) {
forceStopPackageLocked(packageName, pkgUid, "from pid " + callingPid);
}
}
}
} finally {
Binder.restoreCallingIdentity(callingId);
}
}
pms.getPackageUid
@Override
public int getPackageUid(String packageName, int userId) {
if (!sUserManager.exists(userId)) return -1;
enforceCrossUserPermission(Binder.getCallingUid(), userId, false, false, "get package uid");
// reader
synchronized (mPackages) {
PackageParser.Package p = mPackages.get(packageName);
if(p != null) {
return UserHandle.getUid(userId, p.applicationInfo.uid);
//如果包存在，拿包的uid和当前用户的uid出来去
}
PackageSetting ps = mSettings.mPackages.get(packageName);
if((ps == null) || (ps.pkg == null)
|| (ps.pkg.applicationInfo == null)) {
return -1;
}
p = ps.pkg;
return p != null ?
UserHandle.getUid(userId, p.applicationInfo.uid)
: -1;
}
}
getUid
/**
* Returns the uid that is composed from the userId and the appId.
* @hide
*/
public static final int getUid(int userId, int appId) {
if (MU_ENABLED) {
return userId * PER_USER_RANGE + (appId % PER_USER_RANGE);
} else {
return appId;
}
}
pms.setPackageStoppedState
@Override
public void setPackageStoppedState(String packageName, boolean stopped, int userId) {
if (!sUserManager.exists(userId)) return;
final int uid = Binder.getCallingUid();
final int permission = mContext.checkCallingOrSelfPermission(
android.Manifest.permission.CHANGE_COMPONENT_ENABLED_STATE);
final boolean allowedByPermission = (permission == PackageManager.PERMISSION_GRANTED);
enforceCrossUserPermission(uid, userId, true, true, "stop package");
// writer
synchronized (mPackages) {
if (mSettings.setPackageStoppedStateLPw(this, packageName, stopped,
allowedByPermission, uid, userId)) {
scheduleWritePackageRestrictionsLocked(userId);
}
}
}
关于这个uid需要说明下的是，一般的非系统级别的，除了uid一样外，两个包还需要一样的签名。
The name of a Linux user ID that will be shared with other
applications. By default, Android assigns each application its own
unique user ID. However, if this attribute is set to the same value
for two or more applications, they will all share the same ID —
provided that they are alsosigned by the same certificate.
Application with the same user ID can access each other’s data and, if
desired, run in the same process.
对于上面那个函数，我们不再深究下去，看下它调用的另外一个函数
forceStopPackageLocked
private void forceStopPackageLocked(final String packageName, int uid, String reason) {
forceStopPackageLocked(packageName, UserHandle.getAppId(uid), false,
false, true, false, false, UserHandle.getUserId(uid), reason);
／／参数真多
Intent intent = new Intent(Intent.ACTION_PACKAGE_RESTARTED,
Uri.fromParts("package", packageName, null));
if (!mProcessesReady) {
intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY
| Intent.FLAG_RECEIVER_FOREGROUND);
}
intent.putExtra(Intent.EXTRA_UID, uid);
intent.putExtra(Intent.EXTRA_USER_HANDLE, UserHandle.getUserId(uid));
broadcastIntentLocked(null, null, intent,
null, null, 0, null, null, null, AppOpsManager.OP_NONE,
null, false, false, MY_PID, Process.SYSTEM_UID,
UserHandle.getUserId(uid));
}
private final boolean forceStopPackageLocked(String packageName, int appId,
boolean callerWillRestart, boolean purgeCache, boolean doit,
boolean evenPersistent, boolean uninstalling, int userId, String reason) {
int i;
...
if (doit) {//doit为真
final ArrayMap<String, SparseArray<Long>> pmap = mProcessCrashTimes.getMap();
for (int ip = pmap.size() - 1; ip >= 0; ip--) {
SparseArray<Long> ba = pmap.valueAt(ip);
for (i = ba.size() - 1; i >= 0; i--) {
boolean remove = false;
final int entUid = ba.keyAt(i);
if (packageName != null) {
if (userId == UserHandle.USER_ALL) {
if (UserHandle.getAppId(entUid) == appId) {
remove = true;
}
} else {
if (entUid == UserHandle.getUid(userId, appId)) {
remove = true;
}
}
} else if (UserHandle.getUserId(entUid) == userId) {
remove = true;
}
if (remove) {//找到记录就移除
ba.removeAt(i);
}
}
if (ba.size() == 0) {
pmap.removeAt(ip);
}
}
}
boolean didSomething = killPackageProcessesLocked(packageName, appId,
userId,-100, callerWillRestart, true, doit, evenPersistent,
packageName == null ? ("stop user " + userId) : ("stop " + packageName));
//这哥们真实节约啊，还弄个三元操作到参数里面去
if (mStackSupervisor.finishDisabledPackageActivitiesLocked(
packageName, null, doit, evenPersistent, userId)) {
if (!doit) {
return true;
}
didSomething = true;
}
//关闭service
if (mServices.bringDownDisabledPackageServicesLocked(
packageName, null, userId, evenPersistent, doit)) {
if (!doit) {
return true;
}
didSomething = true;
}
if (packageName == null) {
// Remove all sticky broadcasts from this user.
mStickyBroadcasts.remove(userId);
}
//清空contentProvider
ArrayList<ContentProviderRecord> providers = new ArrayList<>();
if (mProviderMap.collectPackageProvidersLocked(packageName, null, doit, evenPersistent,
userId, providers)) {
if (!doit) {
return true;
}
didSomething = true;
}
for (i = providers.size() - 1; i >= 0; i--) {
removeDyingProviderLocked(null, providers.get(i), true);
}
// Remove transient permissions granted from/to this package/user
removeUriPermissionsForPackageLocked(packageName, userId, false);
//关广播接收
if (doit) {
for (i = mBroadcastQueues.length - 1; i >= 0; i--) {
didSomething |= mBroadcastQueues[i].cleanupDisabledPackageReceiversLocked(
packageName, null, userId, doit);
}
}
//删除pending的intent
if (packageName == null || uninstalling) {
if (mIntentSenderRecords.size() > 0) {
Iterator<WeakReference<PendingIntentRecord>> it
= mIntentSenderRecords.values().iterator();
while (it.hasNext()) {
WeakReference<PendingIntentRecord> wpir = it.next();
if (wpir == null) {
it.remove();
continue;
}
PendingIntentRecord pir = wpir.get();
if (pir == null) {
it.remove();
continue;
}
if (packageName == null) {
// Stopping user, remove all objects for the user.
if (pir.key.userId != userId) {
// Not the same user, skip it.
continue;
}
} else {
if (UserHandle.getAppId(pir.uid) != appId) {
// Different app id, skip it.
continue;
}
if (userId != UserHandle.USER_ALL &&
pir.key.userId != userId) {
// Different user, skip it.
continue;
}
if (!pir.key.packageName.equals(packageName)) {
// Different package, skip it.
continue;
}
}
if (!doit) {
return true;
}
didSomething = true;
it.remove();
pir.canceled = true;
if (pir.key.activity != null &&
pir.key.activity.pendingResults != null) {
pir.key.activity.pendingResults.remove(pir.ref);
}
}
}
}
if (doit) {
if (purgeCache && packageName != null) {
AttributeCache ac = AttributeCache.instance();
if (ac != null) {
ac.removePackage(packageName);
}
}
if (mBooted) {
mStackSupervisor.resumeTopActivitiesLocked();
mStackSupervisor.scheduleIdleLocked();
}
}
return didSomething;
}
未完待续。。。
最近在android weekly 看到一篇类似的文章，贴下地址，写得挺好的
[Android 进程绝杀技–forceStop]{http://www.diycode.cc/topics/374}