Android 中build.prop 文件与 getprop 命令

Android 中build.prop 文件与 getprop 命令

在android系统中，它的根文件系统下有几个用于启动系统时需要的配置文件：

1. /init.rc
2. /default.prop
3. /system/build.prop
   

我们先看看 build.prop 里面到底有些什么东西：

E:\AndroidProject\NowaMagic>adb shell
shell@android:/ $ su
su
root@android:/ # cd system
cd system
root@android:/system # cat build.prop
cat build.prop
# begin build properties
# autogenerated by buildinfo.sh
ro.build.id=JRO03L
ro.build.display.id=JRO03L
ro.build.version.incremental=JLB21.0
ro.build.version.sdk=16
ro.build.version.codename=REL
ro.build.version.release=4.1.1
ro.build.date=Thu Aug 1 17:50:59 CST 2013
ro.build.date.utc=1375350659
ro.build.type=user
ro.build.user=builder
ro.build.host=taishan
ro.build.tags=release-keys
ro.product.model=MI 2
ro.product.brand=Xiaomi
ro.product.name=aries
ro.product.device=aries
ro.product.board=MSM8960
ro.product.cpu.abi=armeabi-v7a
ro.product.cpu.abi2=armeabi
ro.product.manufacturer=Xiaomi
ro.product.locale.language=zh
ro.product.locale.region=CN
ro.wifi.channels=
ro.board.platform=msm8960
# ro.build.product is obsolete; use ro.product.device
ro.build.product=aries
# Do not try to parse ro.build.description or .fingerprint
ro.build.description=aries-user 4.1.1 JRO03L JLB21.0 release-keys
ro.build.fingerprint=Xiaomi/aries/aries:4.1.1/JRO03L/JLB21.0:user/release-keys
ro.build.characteristics=nosdcard
# end build properties
#
# system.prop for surf
#

rild.libpath=/system/lib/libril-qc-qmi-1.so
rild.libargs=-d /dev/smd0
persist.rild.nitz_plmn=
persist.rild.nitz_long_ons_0=
persist.rild.nitz_long_ons_1=
persist.rild.nitz_long_ons_2=
persist.rild.nitz_long_ons_3=
persist.rild.nitz_short_ons_0=
persist.rild.nitz_short_ons_1=
persist.rild.nitz_short_ons_2=
persist.rild.nitz_short_ons_3=
ril.subscription.types=RUIM
DEVICE_PROVISIONED=1
debug.sf.hw=1
debug.egl.hw=1
debug.composition.type=dyn
debug.mdpcomp.maxlayer=3
debug.mdpcomp.logs=0

ro.sf.lcd_density=320

# save modem ramdump to sdcard
persist.radio.parsedump=1
persist.radio.ramdump_sdcard=0
persist.radio.ramdump_num=3

#
# system props for the cne module
#
#persist.cne.bat.range.low.med=30
#persist.cne.bat.range.med.high=60
#persist.cne.loc.policy.op=/system/etc/OperatorPolicy.xml
#persist.cne.loc.policy.user=/system/etc/UserPolicy.xml
#persist.cne.bwbased.rat.sel=false
#persist.cne.snsr.based.rat.mgt=false
#persist.cne.bat.based.rat.mgt=false
#persist.cne.rat.acq.time.out=30000
#persist.cne.rat.acq.retry.tout=0
#persist.cne.feature=1

ro.hdmi.enable=true
lpa.decode=false
lpa.use-stagefright=true

#system props for the MM modules

media.stagefright.enable-player=true
media.stagefright.enable-http=true
media.stagefright.enable-aac=true
media.stagefright.enable-qcp=true
media.stagefright.enable-fma2dp=true
media.stagefright.enable-scan=true
mmp.enable.3g2=true

#
# system props for the data modules
#
ro.use_data_netmgrd=true

#system props for time-services
#persist.timed.enable=true

# System props for audio
persist.audio.fluence.mode=endfire
persist.audio.vr.enable=false
persist.audio.handset.mic=digital

# System prop to select audio resampler quality
af.resampler.quality=255
# System prop to select MPQAudioPlayer by default on mpq8064
mpq.audio.decode=true

#
# system prop for opengles version
#
# 131072 is decimal for 0x20000 to report version 2
ro.opengles.version=131072

#
# system property for Bluetooth Handsfree Profile version
#
ro.bluetooth.hfp.ver=1.6
#
#system prop for Bluetooth hci transport
ro.qualcomm.bt.hci_transport=smd
#
# system prop for requesting Master role in incoming Bluetooth connection.
#
ro.bluetooth.request.master=true
#
# system prop for Bluetooth Auto connect for remote initated connections
#
ro.bluetooth.remote.autoconnect=true
# system property for Bluetooth discoverability time out in seconds
# 0: Always discoverable
#debug.bt.discoverable_time=0

#system prop for switching gps driver to qmi
persist.gps.qmienabled=true

# System property for cabl
ro.qualcomm.cabl=0

# System property for csc
debug.csc.poll=0

# System props for telephony
# System prop to turn on CdmaLTEPhone always
# telephony.lteOnCdmaDevice=1

#
# System prop for sending transmit power request to RIL during WiFi hotspot on/off
#
ro.ril.transmitpower=true

#
#Simulate sdcard on /data/media
#
persist.fuse_sdcard=true
ro.hwui.text_cache_width=2048
ro.hwui.texture_cache_size=48

#
# Supports warmboot capabilities
#
ro.warmboot.capability=1

#snapdragon value add features
ro.qcom.audio.ssr=true

persist.sys.strictmode.disable=true
power.webview.DM=false

#enable cdrom installer
persist.service.cdrom.enable=1

#
# Haptic
#
ro.haptic.vibrate_ex.enabled=1
sys.haptic.long.weak=0,127,10,50,20,-50,10
sys.haptic.long.normal=0,80,-80,10
sys.haptic.long.strong=0,100,-100,10
sys.haptic.down.weak=0,120,10
sys.haptic.down.normal=0,10
sys.haptic.down.strong=0,10
sys.haptic.up.weak=0,30,10
sys.haptic.up.normal=0,10
sys.haptic.up.strong=0,-120,10
sys.haptic.tap.weak=0,40,-5,5,10
sys.haptic.tap.normal=0,10
sys.haptic.tap.strong=0,10

# power mode
persist.sys.aries.power_profile=middle

# button jack mode and switch
persist.sys.button_jack_profile=volume
persist.sys.button_jack_switch=0

# suspend mode capability
ro.warmboot.capability=true

# display preference
persist.sys.display_prefer=0
persist.sys.display_ce=0
debug.enabletr=false

#
# ADDITIONAL_BUILD_PROPERTIES
#
ro.miui.ui.version.code=3
ro.miui.ui.version.name=V5
keyguard.no_require_sim=true
ro.com.android.dataroaming=false
ro.com.android.dateformat=MM-dd-yyyy
ro.config.ringtone=MI.ogg
ro.config.notification_sound=FadeIn.ogg
ro.config.alarm_alert=GoodMorning.ogg
ro.config.sms_received_sound=FadeIn.ogg
ro.config.sms_delivered_sound=MessageComplete.ogg
ro.carrier=unknown
persist.sys.mitalk.enable=true
ro.vendor.extension_library=/system/lib/libqc-opt.so
ro.com.google.clientidbase=android-xiaomi
dalvik.vm.heapstartsize=8m
dalvik.vm.heapgrowthlimit=96m
dalvik.vm.heapsize=384m
dalvik.vm.heaputilization=0.25
dalvik.vm.heapidealfree=8388608
dalvik.vm.heapconcurrentstart=2097152
ro.setupwizard.mode=OPTIONAL
ro.com.google.gmsversion=4.1_r5
net.bt.name=Android
dalvik.vm.stack-trace-file=/data/anr/traces.txt

该文件存放的数据是以这种等号形式存放的，而且它们是键值对成对出现的。

留意最后几行，我们试下用 getprop 命令：

root@android:/ # getprop net.bt.name
getprop net.bt.name
Android
root@android:/ # getprop dalvik.vm.stack-trace-file
getprop dalvik.vm.stack-trace-file
/data/anr/traces.txt
root@android:/ #

很明显，getprop 就是将配置文件 build.prop 里的信息读取出来并经过整理后，并以字典的形式展示给用户的。

它的格式如下：

• getprop  列出所有配置属性值
• getprop [key]  取得对应的key的属性值

如果要修改属性的话，很简单，只需修改字典值就可以了，如：

setprop [key] [value] 设置指定key的属性值。

而 watchprops 监听系统属性的变化，如果期间系统的属性发生变化则把变化的值显示出来。

其实这三个命令都是toolbox的子命令，如果有兴趣的可以看在android源码中看到其对应的源码：system/core/toolbox/

感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！