[MTK]如何默认打开user debug 选项

[Description]

如何默认打开user debug 选项



[Keyword]

user debug root



[Solution]

1. 在android 4.0 之前，这个设置是在frameworks/base/service/..../SystemServer.java 里面设置会根据system property 的persist.service.adb.enable 来设置。您可以看到类似如代码：

// make sure the ADB_ENABLED setting value matches the secure property value

Settings.Secure.putInt(mContentResolver, Settings.Secure.ADB_ENABLED,

"1".equals(SystemProperties.get("persist.service.adb.enable")) ? 1 : 0);
// register observer to listen for settings changes

mContentResolver.registerContentObserver(Settings.Secure.getUriFor(Settings.Secure.ADB_ENABLED),

false, new AdbSettingsObserver());



而这个persist.service.adb.enable 默认是放在在default.prop 中，在编译的时候在build/core/main.mk 中确认,

ifeq (true,$(strip $(enable_target_debugging)))

# Target is more debuggable and adbd is on by default

ADDITIONAL_DEFAULT_PROPERTIES += ro.debuggable=1 persist.service.adb.enable=1

# Include the debugging/testing OTA keys in this build.

INCLUDE_TEST_OTA_KEYS := true

else # !enable_target_debugging

# Target is less debuggable and adbd is off by default

ADDITIONAL_DEFAULT_PROPERTIES += ro.debuggable=0 persist.service.adb.enable=0

endif # !enable_target_debugging

您需要将: ADDITIONAL_DEFAULT_PROPERTIES += ro.debuggable=0 persist.service.adb.enable=0 改成

ADDITIONAL_DEFAULT_PROPERTIES += ro.debuggable=1 persist.service.adb.enable=1



2. 在android 4.0 之后，因为adb 的控制，统一使用了persist.sys.usb.config 来控制，于是对应的设置点也改到了frameworks/base/service/...../usb/UsbDeviceManager.java 中，您也可以看到类似的代码如：

public UsbHandler(Looper looper) {

// persist.sys.usb.config should never be unset. But if it is, set it to "adb"

// so we have a chance of debugging what happened.

mDefaultFunctions = SystemProperties.get("persist.sys.usb.config", "adb");

// sanity check the sys.usb.config system property

// this may be necessary if we crashed while switching USB configurations

String config = SystemProperties.get("sys.usb.config", "none");

if (!config.equals(mDefaultFunctions)) {

Slog.w(TAG, "resetting config to persistent property: " + mDefaultFunctions);

SystemProperties.set("sys.usb.config", mDefaultFunctions);

}

mCurrentFunctions = mDefaultFunctions;

String state = FileUtils.readTextFile(new File(STATE_PATH), 0, null).trim();

updateState(state);

mAdbEnabled = containsFunction(mCurrentFunctions, UsbManager.USB_FUNCTION_ADB);
public void systemReady() {

// make sure the ADB_ENABLED setting value matches the current state

Settings.Secure.putInt(mContentResolver, Settings.Secure.ADB_ENABLED, mAdbEnabled ? 1 : 0);



而这个persist.sys.usb.config 中adb 的配置是在alps/build/tools/post_process_props.py 中根据ro.debuggable = 1 or 0 来设置，1 就是开启adb, 0 即关闭adb debug. 而这个ro.debuggable 也是在alps/build/core/main.mk 中设置，和2.3 修改类似
不过您这样打开之后，对于user 版本adb shell 开启的还是shell 权限，而不是root 权限，如果您需要root 权限，需要再改一下system/core/adb/adb.c 里面的should_drop_privileges() 这个函数，在#ifndef ALLOW_ADBD_ROOT 时return 0; 而不是return 1; 即可。