Platform: RK3288
OS: Android 6.0
Kernel: 3.10.92
Rockchip默认提供了机制来预置第三方APK, 方法很简单：
1. 在device/rockchip/rk3288创建preinstall目录(如果要可卸载，那就创建preinstall_del目录)
2. 将你要预安装的APK放进此目录即可
下面看下实现原理过程：
device/rockchip/common/device.mk中有：
ifneq ($(strip $(TARGET_DEVICE)), )
TARGET_DEVICE_DIR=$(shell test -d device && find device -maxdepth 4 -path '*/$(TARGET_DEVICE)/BoardConfig.mk')
TARGET_DEVICE_DIR := $(patsubst %/,%,$(dir $(TARGET_DEVICE_DIR)))
$(shell python device/rockchip/common/auto_generator.py $(TARGET_DEVICE_DIR) system_app)
$(shell python device/rockchip/common/auto_generator.py $(TARGET_DEVICE_DIR) preinstall)
$(shell python device/rockchip/common/auto_generator.py $(TARGET_DEVICE_DIR) preinstall_del)
-include $(TARGET_DEVICE_DIR)/system_app/preinstall.mk
-include $(TARGET_DEVICE_DIR)/preinstall/preinstall.mk
-include $(TARGET_DEVICE_DIR)/preinstall_del/preinstall.mk
endif
auto_generator.py是个python脚本，用于生成Android.mk和preinstall.mk文件，
def main(argv):
preinstall_dir = os.path.join(argv[1] + '/' + argv[2])
if os.path.exists(preinstall_dir):
#Use to define modules for install
makefile_path = preinstall_dir + '/Android.mk'
#Use to include modules
include_path = preinstall_dir + '/preinstall.mk'
if os.path.exists(makefile_path):
os.remove(makefile_path)
if os.path.exists(include_path):
os.remove(include_path)
makefile = file(makefile_path, 'w')
includefile = file(include_path, 'w')
makefile.write("LOCAL_PATH := $(my-dir)\n\n")
for root, dirs, files in os.walk(preinstall_dir):
for file_name in files:
p = re.compile(r'\S*(?=.apk\b)')
found = p.search(file_name)
if found:
makefile.write(templet %(found.group(), argv[2]))
includefile.write('PRODUCT_PACKAGES += %s\n' %found.group())
makefile.close()
includefile.close()
Android.mk用于制定编译规则，如我在preinstall目录下放了个AVSourceTester.apk，那么生成的文件内容是
LOCAL_PATH := $(my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := AVSourceTester
LOCAL_MODULE_CLASS := APPS
LOCAL_MODULE_PATH := $(TARGET_OUT)/preinstall
LOCAL_SRC_FILES := $(LOCAL_MODULE)$(COMMON_ANDROID_PACKAGE_SUFFIX)
LOCAL_CERTIFICATE := PRESIGNED
LOCAL_DEX_PREOPT := false
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
include $(BUILD_PREBUILT)
preinstall.mk内容如下：
PRODUCT_PACKAGES += AVSourceTester
编译系统之后，生成路径是
out/target/product/rk3288/system/preinstall/AVSourceTester/AVSourceTester.apk
系统开机之后会调用copyDirectory()@PackageManagerService.java
File preinstallAppDir = new File(Environment.getRootDirectory(), "preinstall");
File preinstallAppDelDir = new File(Environment.getRootDirectory(),
"preinstall_del");
if ((!SystemProperties.getBoolean("persist.sys.preinstalled", false)) &&
(!"trigger_restart_min_framework".equals(SystemProperties.get("vold.decrypt", null)))) {
// mPreInstallObserver = new AppDirObserver(
// mPreinstallAppDir.getPath(), OBSERVER_EVENTS, false);
// mPreInstallObserver.startWatching();
if (preinstallAppDir.exists()) {
// scanDirLI(mPreinstallAppDir, 0, scanMode, 0);
copyPackagesToAppInstallDir(preinstallAppDir);
}
// mPreInstallDelObserver = new AppDirObserver(
// mPreinstallAppDelDir.getPath(), OBSERVER_EVENTS, false);
// mPreInstallDelObserver.startWatching();
if (preinstallAppDelDir.exists()) {
copyPackagesToAppInstallDir(preinstallAppDelDir);
deletePreinstallDir(preinstallAppDelDir);
}
SystemProperties.set("persist.sys.preinstalled", "1");
}//$_rockchip_$_modify_end
关键函数是copyPackagesToAppInstallDir()，它会把preinstall目录下的安装文件copy到安装目录。
这样安装就成功了。
安装preinstall和preinstall_del的区别在于后者在安装完之后会删除系统目录下的apk，因此要是做了恢复出厂设置或者卸载动作，那就不能恢复了。
删除函数是deletePreinstallDir(),通过init中的ctl命令实现。
private void deletePreinstallDir(File dir) {
String[] files = dir.list();
if (files != null) {
Slog.d(TAG, "Ready to cleanup preinstall");
SystemProperties.set("ctl.start", "preinst_clr");
}
}
不过在source code中并没有找到preinst_clr这个service,可以在init.rc中自己添加下，
参考的是 Nu3001/device_rockchip_rksdk
service preinst_clr /system/bin/preinstall_cleanup.sh
disabled
oneshot
preinstall_cleanup.sh这个文件默认是有的，本质是直接删除apk。
#!/system/bin/sh
log -t PackageManager "Start to clean up /system/preinstall_del/"
mount -o rw,remount -t ext4 /system
rm system/preinstall_del/*.*
mount -o ro,remount -t ext4 /system
转自：https://blog.csdn.net/kris_fei/article/details/78582665
