Android(安卓)build.prop生成过程
本文简要分析一下build.prop是如何生成的。Android的build.prop文件是在Android编译时刻收集的各种property(LCD density/语言/编译时间, etc.),编译完成之后,文件生成在out/target/product/<board>/system/目录下。在Android运行时刻可以通过property_get()[c/c++域] / SystemProperties_get*()[Java域]读取这些属性值。
build.prop的生成是由make系统解析build/core/Makefile完成。相关脚本如下:
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- BUILDINFO_SH:=build/tools/buildinfo.sh
- $(INSTALLED_BUILD_PROP_TARGET):$(BUILDINFO_SH)$(INTERNAL_BUILD_ID_MAKEFILE)$(BUILD_SYSTEM)/version_defaults.mk$(wildcard$(TARGET_DEVICE_DIR)/system.prop)
- @echoTargetbuildinfo:$@
- @mkdir-p$(dir$@)
- $(hide)TARGET_BUILD_TYPE="$(TARGET_BUILD_VARIANT)"\
- TARGET_DEVICE="$(TARGET_DEVICE)"\
- PRODUCT_NAME="$(TARGET_PRODUCT)"\
- PRODUCT_BRAND="$(PRODUCT_BRAND)"\
- PRODUCT_DEFAULT_LANGUAGE="$(calldefault-locale-language,$(PRODUCT_LOCALES))"\
- PRODUCT_DEFAULT_REGION="$(calldefault-locale-region,$(PRODUCT_LOCALES))"\
- PRODUCT_DEFAULT_WIFI_CHANNELS="$(PRODUCT_DEFAULT_WIFI_CHANNELS)"\
- PRODUCT_MODEL="$(PRODUCT_MODEL)"\
- PRODUCT_MANUFACTURER="$(PRODUCT_MANUFACTURER)"\
- PRIVATE_BUILD_DESC="$(PRIVATE_BUILD_DESC)"\
- BUILD_ID="$(BUILD_ID)"\
- BUILD_DISPLAY_ID="$(BUILD_DISPLAY_ID)"\
- BUILD_NUMBER="$(BUILD_NUMBER)"\
- PLATFORM_VERSION="$(PLATFORM_VERSION)"\
- PLATFORM_SDK_VERSION="$(PLATFORM_SDK_VERSION)"\
- PLATFORM_VERSION_CODENAME="$(PLATFORM_VERSION_CODENAME)"\
- BUILD_VERSION_TAGS="$(BUILD_VERSION_TAGS)"\
- TARGET_BOOTLOADER_BOARD_NAME="$(TARGET_BOOTLOADER_BOARD_NAME)"\
- BUILD_FINGERPRINT="$(BUILD_FINGERPRINT)"\
- TARGET_BOARD_PLATFORM="$(TARGET_BOARD_PLATFORM)"\
- TARGET_CPU_ABI="$(TARGET_CPU_ABI)"\
- TARGET_CPU_ABI2="$(TARGET_CPU_ABI2)"\
- TARGET_AAPT_CHARACTERISTICS="$(TARGET_AAPT_CHARACTERISTICS)"\
- bash$(BUILDINFO_SH)>$@
- $(hide)if[-f$(TARGET_DEVICE_DIR)/system.prop];then\
- cat$(TARGET_DEVICE_DIR)/system.prop>>$@;\
- fi
- $(if$(ADDITIONAL_BUILD_PROPERTIES),\
- $(hide)echo>>$@;\
- echo"#">>$@;\
- echo"#ADDITIONAL_BUILD_PROPERTIES">>$@;\
- echo"#">>$@;)
- $(hide)$(foreachline,$(ADDITIONAL_BUILD_PROPERTIES),\
- echo"$(line)">>$@;)
- $(hide)build/tools/post_process_props.py$@
从上面的命令中可以看到,build.prop由三部分组成:BUILDINFO_SH、system.prop、ADDITIONAL_BUILD_PROPERTIES等,对应的写入命令:
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- bash$(BUILDINFO_SH)>$@
- $(hide)if[-f$(TARGET_DEVICE_DIR)/system.prop];then\
- cat$(TARGET_DEVICE_DIR)/system.prop>>$@;\
- fi
- $(hide)$(foreachline,$(ADDITIONAL_BUILD_PROPERTIES),\
- echo"$(line)">>$@;)
[javascript] view plain copy print ?
- 1....
- 2.PRODUCT_DEFAULT_LANGUAGE="$(calldefault-locale-language,$(PRODUCT_LOCALES))"\
- 3.PRODUCT_DEFAULT_REGION="$(calldefault-locale-region,$(PRODUCT_LOCALES))"\
- 4....
2)Makefile中调用build/tools/buildinfo.sh执行脚本,并输出到build.prop
Buildinfo.sh很简单,只是echo一些属性,比如:
[javascript] view plain copy print ?- 1....
- 2.echo"ro.product.locale.language=$PRODUCT_DEFAULT_LANGUAGE"
- 3.echo"ro.product.locale.region=$PRODUCT_DEFAULT_REGION"
- 4....
而,ro.product.locale.language/ ro.product.locale.region就是些属性,等号后面是值。
3)Makefile中直接把$(TARGET_DEVICE_DIR)/system.prop的内容追加到build.prop中。
4)收集ADDITIONAL_BUILD_PROPERTIES中的属性,追加到build.prop中。
ADDITIONAL_BUILD_PROPERTIES又会收集PRODUCT_PROPERTY_OVERRIDES中定义的属性
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- 1.ADDITIONAL_BUILD_PROPERTIES:=\
- 2.$(ADDITIONAL_BUILD_PROPERTIES)\
- 3.$(PRODUCT_PROPERTY_OVERRIDES)
通过build.prop生成过程的分析,可知哪里可以修改原有的属性或加入自己定义属性,那就是2) buildinfo.sh; 3) system.prop; 4) ADDITIONAL_BUILD_PROPERTIES或PRODUCT_PROPERTY_OVERRIDES。不过个人建议改在system.prop或PRODUCT_PROPERTY_OVERRIDES,这对应于具体特定平台或产品的修改。原文:http://blog.csdn.net/thl789/article/details/7014300
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