busybox rootfs 启动脚本分析(一）

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imx6文件系统启动脚本分析。开机运行/sbin/init，读取/etc/inittab文件，进行初始化。

参考链接

http://blog.163.com/wghbeyond@126/blog/static/35166181201051483723579/

/etc/inittab

# see busybox-1.00rc2/examples/inittab for more examples ::sysinit:/etc/rc.d/rcS# 系统启动的时候运行/etc/rc.d/rcS脚本 #::respawn:/etc/rc.d/rc_mxc.S ttymxc0::once:/bin/login root# debug口使用ttymxc0，之运行一次/bin/login，root是传入的参数。 # 这就是为什么登录之后退出就不能再登录。如果想再次运行/bin/login,将once改为respawn #::once:/sbin/getty 115200 ttymxc0# 也可以采用这种形式设置串口，不过这样就需要输入账户密码::sysinit:/etc/rc.d/rc_gpu.S# 系统启动的时候运行rc_gpu.S ::ctrlaltdel:/sbin/reboot # ctrl + alt + del 组合键是运行/sbin/reboot程序。 ::shutdown:/etc/rc.d/rcS stop # 关机的时候运行 /etc/rc.d/rcS stop ::restart:/sbin/init# 重启时运行/sbin/init

/etc/rc.d/rcS

#!/bin/sh# minimal startup script, will work with msh (this is best available in # MMUless format).# load the configuration information . /etc/rc.d/rc.conf# 运行/etc/rc.d/rc.conf 脚本 mode=${1:-start}# 当$1的值不存在或者为空，那么mode=start，否者mode=$1 if [ $mode = "start" ] then services=$cfg_services else services=$cfg_services_r fi cfg_services=${2:-$services}# run the configured sequence for i in $cfg_services do if [ -x /etc/rc.d/init.d/$i ]# 判断/etc/rc.d/init.d/中是否存在$i表示的可执行文件 then /etc/rc.d/init.d/$i $mode# 运行/etc/rc.d/init.d中的shell脚本，start or stop fi doneif [ $# -ge 2 ] # 如果传入脚本的参数个数大于 2 then exit 0# 退出, 返回值为 0 fi # show all kernel log messages #echo 8 > /proc/sys/kernel/printk# run rc.local if present and executable if [ -x /etc/rc.d/rc.local ]# 判断rc.local是否存在，并且可执行 then /etc/rc.d/rc.local $mode# 运行rc.local, mode= start/stop fi

/etc/rc.d/rc.conf

all_services="mount-proc-sys mdev udev hostname devfsd depmod modules filesystems syslog network inetd portmap dropbear sshd boa smb dhcpd settime fslgnome watchdog bluetooth gtk2 pango" all_services_r="pango gtk2 bluetooth watchdog fslgnome settime dhcpd smb boa sshd dropbear portmap inetd network syslog filesystems modules depmod devfsd hostname udev mdev mount-proc-sys" # 启动，运行顺序 cfg_services="mount-proc-sys udev hostname depmod modules filesystems inetd " # 停止，停止顺序与启动顺序相反 cfg_services_r=" inetd filesystems modules depmod hostname udev mount-proc-sys"export HOSTNAME="freescale" export NTP_SERVER="" export MODLIST="" export RAMDIRS="" export TMPFS="tmpfs" export TMPFS_SIZE="512k" export READONLY_FS="" export INETD_ARGS="" export BOA_ARGS="" export SMBD_ARGS="" export NMBD_ARGS="" export DHCP_ARG="" export DEPLOYMENT_STYLE="RAMDISK" export SYSCFG_DHCPC_CMD="udhcpc -b -i " export DROPBEAR_ARGS=""

/etc/rc.d/rc.local

#!/bin/sh # # This script will be executed *after* all the other init scripts. # You can put your own initialization stuff in here if [ -x "/usr/bin/rpm" -a -e "/tmp/ltib" ]# 是否存在可执行文件/usr/bin/rpm，以及/tmp/ltib then echo "rebuilding rpm database" rm -rf /tmp/ltib# 重新创建rpm数据库 rpm --rebuilddb fi# fix up permissions if [ -d /home/user ]# 是否存在/home/user目录 then chown -R user.user /home/user # 更改所有者,所在组 fi# Add nodes when running under the hypervisor and static devices if [ -r /sys/class/misc/fsl-hv/dev -a ! -r /dev/fsl-hv ] # 查看/sys/class/misc/fsl-hv/dev是否可读，并且/dev/fsl-hv不可读 then echo "creating hypervisor nodes" DEVID=`cat /sys/class/misc/fsl-hv/dev` if [ -n "$DEVID" ]# 判断是否为空 then MAJOR="${DEVID%:*}" MINOR="${DEVID##*:}" if [ $ "$MAJOR" -gt 0 $ -a $ "$MINOR" -gt 0 $ ] then rm -f /dev/fsl-hv mknod /dev/fsl-hv c $MAJOR $MINOR fi fi for i in 0 1 2 3 4 5 6 7 do mknod /dev/hvc$i c 229 $i done fi# add the fm device nodes if [ -n "$(cat /proc/devices | grep fm | sed 's/$[0-9]*$.*/\1/')" -a ! -r /dev/fm0 ] then echo "creating fman device nodes" cd /usr/share/doc/fmd-uspace-01.01/test/ sh fm_dev_create cd - fifor i in 0 1 2; do if [ -e /sys/class/graphics/fb$i ]; then chmod 0666 /sys/class/graphics/fb$i/pan fi done

/etc/rc.d/rc_gpu.S

#!/bin/bash CPUREV=$(cat /proc/cpuinfo | grep Revision | awk '{print $3}' | awk '{print substr($0,1,2)}')# 查看cpu的版本，mx6dl读取的是61 FILEVG=/usr/lib/libOpenVG.so FILEVG3D=/usr/lib/libOpenVG_3D.so FILEVG355=/usr/lib/libOpenVG_355.so echo 4 > /sys/module/galcore/parameters/gpu3DMinClock if [ -e $FILEVG3D ] && [ -e $FILEVG355 ] then if [ $CPUREV == "61" ] || [ $CPUREV == "63" ] || [ $CPUREV == "60" ] && [ -e $FILEVG ] then rm -f $FILEVG fi if [ $CPUREV == "61" ] then ln -s $FILEVG3D $FILEVG # 创建软连接 fi if [ $CPUREV == "63" ] then ln -s $FILEVG355 $FILEVG fi if [ $CPUREV == "60" ] then ln -s $FILEVG355 $FILEVG fi fi