android开机启动流程说明.docx

android开机启动流程说明
    第一步:启动linux
   
   
    第二步android系统启动:(system\core\rootdir)
    1./system/bin/service manager: Binder 守护进程;
    ;
    :app-process/app-main;
    VM;
    server
    android service:Register to service Manager
    Launcher
    第三步:应用程序启动:运行package Manager
    l Init进程
    Android系统在启动时首先会启动Linux系统,引导加载Linux Kernel并启动init进程。Init进程是一个由内核启动的用户级进程,是Android系统的第一个进程。该进程的相关代码在platform\system\core\init\。在main函数中,有如下代码:
    open_devnull_stdio();
    log_init();
    INFO("reading config file\n");
    init_parse_config_file("/");
    /* pull the mandline and ramdisk properties file in */
    import_kernel_cmdline(0);
    get_hardware_name(hardware, &revision);
    snprintf(tmp, sizeof(tmp), "/init.%", hardware);
    init_parse_config_file(tmp);
    。*.rc文件定义了在init进程中需要启动哪些进程服务和执行哪些动作。其详细说明参见platform\system\core\init\。:
    service servicemanager /system/bin/servicemanager
    user system
    critical
    onrestart restart zygote
    onrestart restart media
    service vold /system/bin/vold
    socket vold stream 0660 root mount
    ioprio be 2
    d /system/d
    d stream 0660 root system
    socket dnsproxyd stream 0660 root inet
    service debuggerd /system/bin/debuggerd
    service ril-daemon /system/bin/rild
    socket rild stream 660 root radio
    socket rild-debug stream 660 radio system
    user root
    group radio cache inet misc audio sdcard_rw
    service zygote /system/bin/app_process -Xzygote /system/bin --zygote --start-system-server
    socket zygote stream 666
    onrestart write /sys/android_power/request_state wake
    onrestart write /sys/power/state on
    onrestart restart media
    onrestart d
    service drm /system/bin/drmserver
    user drm
    group system root inet
    具体解析过程见platform\system\core\init\。解析所得服务添