Android11(R) system_ext 分区 system_ext

本文主要是介绍Android11(R) system_ext 分区 system_ext_specific 属性，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

android11 开搞

朋友们，最近拿到 androidR 的代码了，让我们来康康有哪些变动，一上来就给我整懵了，编译了 SystemUI 后发现

居然跑到 system\system_ext\priv-app 文件下了，这是什么鬼，又新加分区？之前 Q 版本已经新增了 product 分区，

并且 SystemUI、Launcher3、Settings这些核心应用都存放在此处，现在 R 版本又跑到这个 system_ext 分区下了

关于动态分区之前介绍过 Android10 动态分区介绍

一探究竟

决定编译后 apk 的位置当然是在 Android.mk 或者 Android.bp 中啦，那我们去康康到底配置了啥子属性？

vendor\mediatek\proprietary\packages\apps\SystemUI\Android.bp

system_ext_specific: true,

privileged: true,

vendor\mediatek\proprietary\packages\apps\MtkSettings\Android.bp

system_ext_specific: true,

privileged: true,

packages\apps\Launcher3\Android.mk

LOCAL_PRIVILEGED_MODULE := true

LOCAL_SYSTEM_EXT_MODULE := true

vendor\mediatek\proprietary\packages\apps\Browser\Android.mk

LOCAL_SYSTEM_EXT_MODULE := true

看完上面这些配置可以知道了，

bp 中配置 system_ext_specific: true，就将编译到 system\system_ext\ 中，

privileged: true 决定在 priv-app 文件中，不加 privileged 则编译到 system\system_ext\app\

mk 中配置 LOCAL_SYSTEM_EXT_MODULE := true，就将编译到 system\system_ext\ 中，

LOCAL_PRIVILEGED_MODULE := true 决定在 priv-app 文件中，不加 LOCAL_PRIVILEGED_MODULE 则编译到 system\system_ext\app\

system_ext_specific 和 LOCAL_SYSTEM_EXT_MODULE 的对照关系经过搜索位于

build\soong\androidmk\androidmk\android.go

addStandardProperties(bpparser.BoolType,map[string]string{// Bool properties"LOCAL_IS_HOST_MODULE":             "host","LOCAL_CLANG":                      "clang","LOCAL_FORCE_STATIC_EXECUTABLE":    "static_executable","LOCAL_NATIVE_COVERAGE":            "native_coverage","LOCAL_NO_CRT":                     "nocrt","LOCAL_ALLOW_UNDEFINED_SYMBOLS":    "allow_undefined_symbols","LOCAL_RTTI_FLAG":                  "rtti","LOCAL_PACK_MODULE_RELOCATIONS":    "pack_relocations","LOCAL_TIDY":                       "tidy","LOCAL_USE_CLANG_LLD":              "use_clang_lld","LOCAL_PROPRIETARY_MODULE":         "proprietary","LOCAL_VENDOR_MODULE":              "vendor","LOCAL_ODM_MODULE":                 "device_specific","LOCAL_PRODUCT_MODULE":             "product_specific","LOCAL_SYSTEM_EXT_MODULE":          "system_ext_specific","LOCAL_EXPORT_PACKAGE_RESOURCES":   "export_package_resources","LOCAL_PRIVILEGED_MODULE":          "privileged","LOCAL_AAPT_INCLUDE_ALL_RESOURCES": "aapt_include_all_resources","LOCAL_DONT_MERGE_MANIFESTS":       "dont_merge_manifests","LOCAL_USE_EMBEDDED_NATIVE_LIBS":   "use_embedded_native_libs","LOCAL_USE_EMBEDDED_DEX":           "use_embedded_dex","LOCAL_DEX_PREOPT":                  "dex_preopt.enabled","LOCAL_DEX_PREOPT_APP_IMAGE":        "dex_preopt.app_image","LOCAL_DEX_PREOPT_GENERATE_PROFILE": "dex_preopt.profile_guided","LOCAL_PRIVATE_PLATFORM_APIS": "platform_apis","LOCAL_JETIFIER_ENABLED":      "jetifier",})
}

那么 LOCAL_SYSTEM_EXT_MODULE 这个又是在那里使用的呢？继续在 build 中查找

build\make\core\base_rules.mk

else ifneq ($(filter $(TARGET_OUT_SYSTEM_EXT)/%,$(_path)),)
LOCAL_SYSTEM_EXT_MODULE := true
endif
_path :=else ifeq (true,$(strip $(LOCAL_SYSTEM_EXT_MODULE)))partition_tag := _SYSTEM_EXT# A system_ext-specific module could be on the system_ext partition at# "system_ext" or the system partition at "system/system_ext".actual_partition_tag := $(if $(filter true,$(BOARD_USES_SYSTEM_EXTIMAGE)),system_ext,system)

紧接着查找 TARGET_OUT_SYSTEM_EXT 到

build\make\core\envsetup.mk

TARGET_OUT_SYSTEM_EXT := $PRODUCT_OUT)/$ (TARGET_COPY_OUT_SYSTEM_EXT)

TARGET_COPY_OUT_SYSTEM_EXT := $(_system_ext_path_placeholder)

_system_ext_path_placeholder := ||SYSTEM_EXT-PATH-PH||

再接着找 SYSTEM_EXT

build\make\tools\releasetools\check_target_files_vintf.py

# each partition.
DIR_SEARCH_PATHS = {'/system': ('SYSTEM',),'/vendor': ('VENDOR', 'SYSTEM/vendor'),'/product': ('PRODUCT', 'SYSTEM/product'),'/odm': ('ODM', 'VENDOR/odm', 'SYSTEM/vendor/odm'),'/system_ext': ('SYSTEM_EXT', 'SYSTEM/system_ext'),
}

build\make\target\board\BoardConfigEmuCommon.mk

  ifeq ($(QEMU_USE_SYSTEM_EXT_PARTITIONS),true)BOARD_EMULATOR_DYNAMIC_PARTITIONS_PARTITION_LIST := \system \system_ext \product \vendorTARGET_COPY_OUT_PRODUCT := productBOARD_PRODUCTIMAGE_FILE_SYSTEM_TYPE := ext4TARGET_COPY_OUT_SYSTEM_EXT := system_extBOARD_SYSTEM_EXTIMAGE_FILE_SYSTEM_TYPE := ext4elseTARGET_COPY_OUT_PRODUCT := system/productTARGET_COPY_OUT_SYSTEM_EXT := system/system_extBOARD_EMULATOR_DYNAMIC_PARTITIONS_PARTITION_LIST := \system \vendorendif

build\make\core\board_config.mk

# Now we can substitute with the real value of TARGET_COPY_OUT_SYSTEM_EXT
ifeq ($(TARGET_COPY_OUT_SYSTEM_EXT),$(_system_ext_path_placeholder))
TARGET_COPY_OUT_SYSTEM_EXT := system/system_ext
else ifeq ($(filter system_ext system/system_ext,$(TARGET_COPY_OUT_SYSTEM_EXT)),)
$(error TARGET_COPY_OUT_SYSTEM_EXT must be either 'system_ext' or 'system/system_ext', seeing '$(TARGET_COPY_OUT_SYSTEM_EXT)'.)
endif
PRODUCT_COPY_FILES := $(subst $(_system_ext_path_placeholder),$(TARGET_COPY_OUT_SYSTEM_EXT),$(PRODUCT_COPY_FILES))