Notice that on devices running with + * {@link UserManager#isHeadlessSystemUserMode() headless system user mode}, there is no primary + * user, so it switches back to the user that was in the foreground before the first call to + * {@link #switchUser(ComponentName, UserHandle)} (or fails with + * {@link UserManager#USER_OPERATION_ERROR_UNKNOWN} if that method was not called prior to this + * call). * * @param admin Which {@link DeviceAdminReceiver} this request is associated with. * @return one of the following result codes: diff --git a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java index 34576a6614613..ac2d3b566f703 100644 --- a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java +++ b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java @@ -699,6 +699,14 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager { private DevicePolicyConstants mConstants; + /** + * User to be switched to on {@code logoutUser()}. + * + *
Only used on devices with headless system user mode + */ + @GuardedBy("getLockObject()") + private @UserIdInt int mLogoutUserId = UserHandle.USER_NULL; + private static final boolean ENABLE_LOCK_GUARD = true; /** @@ -9670,6 +9678,7 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager { mStatLogger.dump(pw); pw.println(); pw.println("Encryption Status: " + getEncryptionStatusName(getEncryptionStatus())); + pw.println("Logout user: " + getLogoutUserId()); pw.println(); if (mPendingUserCreatedCallbackTokens.isEmpty()) { @@ -10780,6 +10789,9 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager { Preconditions.checkCallAuthorization(isDeviceOwner(caller)); checkCanExecuteOrThrowUnsafe(DevicePolicyManager.OPERATION_SWITCH_USER); + boolean switched = false; + // Save previous logout user id in case of failure + int logoutUserId = getLogoutUserId(); synchronized (getLockObject()) { long id = mInjector.binderClearCallingIdentity(); try { @@ -10787,16 +10799,55 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager { if (userHandle != null) { userId = userHandle.getIdentifier(); } - return mInjector.getIActivityManager().switchUser(userId); + Slogf.i(LOG_TAG, "Switching to user %d (logout user is %d)", userId, logoutUserId); + setLogoutUserIdLocked(UserHandle.USER_CURRENT); + switched = mInjector.getIActivityManager().switchUser(userId); + if (!switched) { + Slogf.w(LOG_TAG, "Failed to switch to user %d", userId); + } + return switched; } catch (RemoteException e) { Slogf.e(LOG_TAG, "Couldn't switch user", e); return false; } finally { mInjector.binderRestoreCallingIdentity(id); + if (!switched) { + setLogoutUserIdLocked(logoutUserId); + } } } } + private @UserIdInt int getLogoutUserId() { + if (!mInjector.userManagerIsHeadlessSystemUserMode()) { + // mLogoutUserId is USER_SYSTEM as well, but there's no need to acquire the lock + return UserHandle.USER_SYSTEM; + } + synchronized (getLockObject()) { + return mLogoutUserId; + } + } + + private void setLogoutUserId(@UserIdInt int userId) { + if (!mInjector.userManagerIsHeadlessSystemUserMode()) return; // ignore + + synchronized (getLockObject()) { + setLogoutUserIdLocked(userId); + } + } + + @GuardedBy("getLockObject()") + private void setLogoutUserIdLocked(@UserIdInt int userId) { + if (!mInjector.userManagerIsHeadlessSystemUserMode()) return; // ignore + + if (userId == UserHandle.USER_CURRENT) { + userId = getCurrentForegroundUserId(); + } + + Slogf.d(LOG_TAG, "setLogoutUserId(): %d -> %d", mLogoutUserId, userId); + mLogoutUserId = userId; + } + @Override public int startUserInBackground(ComponentName who, UserHandle userHandle) { Objects.requireNonNull(who, "ComponentName is null"); @@ -10818,10 +10869,11 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager { return UserManager.USER_OPERATION_ERROR_MAX_RUNNING_USERS; } + Slogf.i(LOG_TAG, "Starting user %d in background", userId); if (mInjector.getIActivityManager().startUserInBackground(userId)) { - Slogf.i(LOG_TAG, "Started used %d in background", userId); return UserManager.USER_OPERATION_SUCCESS; } else { + Slogf.w(LOG_TAG, "failed to start user %d in background", userId); return UserManager.USER_OPERATION_ERROR_UNKNOWN; } } catch (RemoteException e) { @@ -10869,13 +10921,30 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager { return UserManager.USER_OPERATION_ERROR_MANAGED_PROFILE; } + // TODO(b/204585343): remove the headless system user check? + if (mInjector.userManagerIsHeadlessSystemUserMode() && callingUserId != mInjector + .binderWithCleanCallingIdentity(() -> getCurrentForegroundUserId())) { + Slogf.d(LOG_TAG, "logoutUser(): user %d is in background, just stopping, not switching", + callingUserId); + return stopUserUnchecked(callingUserId); + } + + int logoutUserId = getLogoutUserId(); + if (logoutUserId == UserHandle.USER_NULL) { + // Could happen on devices using headless system user mode when called before calling + // switchUser() or startUserInBackground() first + Slogf.w(LOG_TAG, "logoutUser(): could not determine which user to switch to"); + return UserManager.USER_OPERATION_ERROR_UNKNOWN; + } final long id = mInjector.binderClearCallingIdentity(); try { - if (!mInjector.getIActivityManager().switchUser(UserHandle.USER_SYSTEM)) { - Slogf.w(LOG_TAG, "Failed to switch to primary user"); - // This should never happen as target user is UserHandle.USER_SYSTEM + Slogf.i(LOG_TAG, "logoutUser(): switching to user %d", logoutUserId); + if (!mInjector.getIActivityManager().switchUser(logoutUserId)) { + Slogf.w(LOG_TAG, "Failed to switch to user %d", logoutUserId); + // This should never happen as target user is determined by getPreviousUserId() return UserManager.USER_OPERATION_ERROR_UNKNOWN; } + setLogoutUserId(UserHandle.USER_CURRENT); } catch (RemoteException e) { // Same process, should not happen. return UserManager.USER_OPERATION_ERROR_UNKNOWN; @@ -10886,7 +10955,8 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager { return stopUserUnchecked(callingUserId); } - private int stopUserUnchecked(int userId) { + private int stopUserUnchecked(@UserIdInt int userId) { + Slogf.i(LOG_TAG, "Stopping user %d", userId); final long id = mInjector.binderClearCallingIdentity(); try { switch (mInjector.getIActivityManager().stopUser(userId, true /*force*/, null)) {