i.mx6 Android5.1.1 系统属性
属性变更的请求时init事件循环处理的另一个事件，在Android平台中，为了让运行中的所有进程共享系统运行时所需要的各种设置值，系统开辟了属性存储区域，并提供了访问该区域的API。属性由键(key)与值(value)构成，其表现形式为“键=值”。在Linux系统中，属性服务主要用来设置环境变量，提供各进程访问设定的环境变量值。在Android平台中，在访问属性值时，添加了访问权限控制，增强了访问的安全性。系统中所有运行中的进程都可以访问属性值，但仅有init进程才能修改属性值。其他进程修改属性值时，必须向init进程提出请求，最终由init进程负责修改属性值。在此过程中，init进程会先检查各属性的访问权限，而后再修改属性值，当属性值更改后，若定义在init.rc文件中的某个特定条件得到满足，则与此条件相匹配的动作就会发生，每个动作都有一个触发器，决定动作的执行时间，记录在“on property”关键字后的命令即被执行。
root@sabresd_6dq:/ # getprop [CPU]: [i.MX6 Cortex A9 1.0GHz] [FileSystemVersion]: [001] [RAM]: [DDR3 1.0GB] [SoftwarePartNumber]: [0713625406xx] [alsa.mixer.capture.headset]: [Capture] [alsa.mixer.capture.master]: [Capture] [alsa.mixer.playback.headset]: [Headphone] [alsa.mixer.playback.master]: [Playback] [alsa.mixer.playback.speaker]: [Playback] [back_camera_orient]: [0] [camera.disable_zsl_mode]: [1] [dalvik.vm.dex2oat-Xms]: [64m] [dalvik.vm.dex2oat-Xmx]: [512m] [dalvik.vm.dexopt-flags]: [m=y] [dalvik.vm.heapgrowthlimit]: [80m] [dalvik.vm.heapmaxfree]: [8m] [dalvik.vm.heapminfree]: [512k] [dalvik.vm.heapsize]: [384m] [dalvik.vm.heapstartsize]: [8m] [dalvik.vm.heaptargetutilization]: [0.75] [dalvik.vm.image-dex2oat-Xms]: [64m] [dalvik.vm.image-dex2oat-Xmx]: [64m] [dalvik.vm.isa.arm.features]: [default] [dalvik.vm.stack-trace-file]: [/data/anr/traces.txt] [debug.egl.hw]: [1] [debug.force_rtl]: [0] [debug.sf.enable_hgl]: [1] [debug.sf.showfps]: [0] [dev.bootcomplete]: [1] [front_camera_orient]: [0] [gsm.current.phone-type]: [1] [gsm.network.type]: [Unknown] [gsm.operator.alpha]: [] [gsm.operator.iso-country]: [] [gsm.operator.isroaming]: [false] [gsm.operator.numeric]: [] [gsm.ril.delay]: [15] [gsm.sim.operator.alpha]: [] [gsm.sim.operator.iso-country]: [] [gsm.sim.operator.numeric]: [] [gsm.sim.state]: [NOT_READY] [hw.backlight.dev]: [pwm-backlight.0] [hwc.enable_dither]: [1] [hwc.stretch.filter]: [1] [init.svc.adbd]: [running] [init.svc.bootanim]: [stopped] [init.svc.console]: [running] [init.svc.debuggerd]: [running] [init.svc.drm]: [running] [init.svc.healthd]: [running] [init.svc.installd]: [running] [init.svc.keystore]: [running] [init.svc.lmkd]: [running] [init.svc.logd]: [running] [init.svc.media]: [running] [init.svc.netd]: [running] [init.svc.ril-daemon]: [running] [init.svc.sdcard]: [running] [init.svc.servicemanager]: [running] [init.svc.surfaceflinger]: [running] [init.svc.ueventd]: [running] [init.svc.vold]: [running] [init.svc.watchdogd]: [running] [init.svc.wifi_mac]: [stopped] [init.svc.zygote]: [running] [media.omxgm.enable-player]: [1] [media.omxgm.enable-record]: [1] [media.omxgm.enable-scan]: [1] [media.wfd.video-bitrate]: [3000000] [net.bt.name]: [Android] [net.change]: [net.qtaguid_enabled] [net.hostname]: [android-83a3ccab22cf4b3e] [net.qtaguid_enabled]: [1] [net.tcp.default_init_rwnd]: [60] [persist.sampling_profiler]: [1] [persist.sys.dalvik.vm.lib.2]: [libart.so] [persist.sys.profiler_ms]: [0] [persist.sys.strictmode.disable]: [1] [persist.sys.strictmode.visual]: [0] [persist.sys.usb.config]: [mtp,adb] [ro.FSL_AAC_PARSER]: [1] [ro.FSL_ASF_PARSER]: [0] [ro.FSL_AVI_PARSER]: [1] [ro.FSL_FLAC_PARSER]: [1] [ro.FSL_FLV_PARSER]: [1] [ro.FSL_MKV_PARSER]: [1] [ro.FSL_MPG2_PARSER]: [1] [ro.FSL_REAL_PARSER]: [0] [ro.adb.secure]: [0] [ro.allow.mock.location]: [1] [ro.baseband]: [unknown] [ro.board.platform]: [imx6] [ro.boot.console]: [ttymxc0] [ro.boot.hardware]: [freescale] [ro.boot.selinux]: [disabled] [ro.boot.serialno]: [102231d4e6b416f0] [ro.boot.storage_type]: [emmc] [ro.bootloader]: [unknown] [ro.bootmode]: [unknown] [ro.build.characteristics]: [tablet] [ro.build.date.utc]: [1498616731] [ro.build.date]: [三 6月 28 10:25:31 CST 2017] [ro.build.description]: [sabresd_6dq-user 5.1.1 2.1.0-ga-rc3 20151218 release-keys] [ro.build.display.id]: [2.1.0-ga-rc3 release-keys] [ro.build.fingerprint]: [Freescale/sabresd_6dq/sabresd_6dq:5.1.1/2.1.0-ga-rc3/20151218:user/release-keys] [ro.build.flavor]: [sabresd_6dq-user] [ro.build.host]: [imx6] [ro.build.id]: [2.1.0-ga-rc3] [ro.build.product]: [sabresd_6dq] [ro.build.tags]: [release-keys] [ro.build.type]: [user] [ro.build.user]: [lee] [ro.build.version.all_codenames]: [REL] [ro.build.version.base_os]: [] [ro.build.version.codename]: [REL] [ro.build.version.incremental]: [20151218] [ro.build.version.release]: [5.1.1] [ro.build.version.sdk]: [22] [ro.build.version.security_patch]: [2015-11-01] [ro.carrier]: [unknown] [ro.config.alarm_alert]: [Alarm_Classic.ogg] [ro.config.notification_sound]: [OnTheHunt.ogg] [ro.crypto.state]: [unencrypted] [ro.dalvik.vm.native.bridge]: [0] [ro.debuggable]: [1] [ro.factorytest]: [0] [ro.hardware.lightsensor]: [/sys/class/i2c-dev/i2c-2/device/2-0044/] [ro.hardware]: [freescale] [ro.lightsensor.threshold]: [20] [ro.opengles.version]: [131072] [ro.product.board]: [SABRESD] [ro.product.brand]: [Freescale] [ro.product.cpu.abi2]: [armeabi] [ro.product.cpu.abi]: [armeabi-v7a] [ro.product.cpu.abilist32]: [armeabi-v7a,armeabi] [ro.product.cpu.abilist64]: [] [ro.product.cpu.abilist]: [armeabi-v7a,armeabi] [ro.product.device]: [sabresd_6dq] [ro.product.locale.language]: [en] [ro.product.locale.region]: [US] [ro.product.manufacturer]: [Freescale] [ro.product.model]: [SABRESD-MX6DQ] [ro.product.name]: [sabresd_6dq] [ro.revision]: [0] [ro.ril.wake_lock_timeout]: [300] [ro.runtime.firstboot]: [1507795631553] [ro.secure]: [0] [ro.serialno]: [102231d4e6b416f0] [ro.sf.hwrotation]: [0] [ro.sf.lcd_density]: [160] [ro.soc]: [i.MX6DL] [ro.tether.denied]: [false] [ro.wifi.channels]: [] [rw.VIDEO_RENDER_NAME]: [video_render.surface] [selinux.reload_policy]: [1] [service.bootanim.exit]: [1] [sys.boot_completed]: [1] [sys.emulated.battery]: [1] [sys.interactive]: [active] [sys.sysctl.extra_free_kbytes]: [12294] [sys.usb.config]: [mtp,adb] [sys.usb.state]: [mtp,adb] [vold.post_fs_data_done]: [1] [wifi.ap.interface]: [wlan0] [wifi.interface]: [wlan0] [wlan.interface]: [wlan0]
