IMX6ULL - Linux根文件系統(rootfs)構建

Author: zzssdd2

E-mail: [e-mail]

一、Ubuntu-base20.04.3

Ubuntu官方已經制作好了各架構、各版本的base版根文件系統，只需下載下來做少許改動即可。

1. 下載Ubuntu Base 20.04.3 LTS (Focal Fossa)

   ubuntu-base-20.04.3-base-armhf.tar.gz	2021-08-19 10:56	22M
   

2. 解壓

   mkdir rootfs
   sudo chmod 777 rootfs
   tar -zxvf ubuntu-base-20.04.3-base-armhf.tar.gz -C rootfs
   #避免后面更新軟件報錯
   sudo chmod 777 ./rootfs/tmp/
   

3. 安裝工具

   sudo apt-get install qemu-user-static
   sudo cp /usr/bin/qemu-arm-static ./rootfs/usr/bin/
   

4. 拷貝主機DNS

   sudo cp /etc/resolv.conf ./rootfs/etc/resolv.conf
   

5. 更換下載源

   cp ./rootfs/etc/apt/source.list ./rootfs/etc/apt/source.list.bak
   vim ./rootfs/etc/apt/source.list
   `Esc` + `:`
   %s/ports.ubuntu.com/mirror.tuna.tsinghua.edu.cn/g
   `Enter`
   

6. 創建掛載腳本vim mount.sh

   內容如下：

   #!/bin/bash
   mnt() {
   	echo "MOUNTING"
   	sudo mount -t proc /proc ${2}proc
   	sudo mount -t sysfs /sys ${2}sys
   	sudo mount -o bind /dev ${2}dev
   	sudo mount -o bind /dev/pts ${2}dev/pts
   	sudo chroot ${2}
   }
   umnt() {
   	echo "UNMOUNTING"
   	sudo umount ${2}proc
   	sudo umount ${2}sys
   	sudo umount ${2}dev/pts
   	sudo umount ${2}dev
   }
   
   if [ "$1" == "-m" ] && [ -n "$2" ] ;
   then
   	mnt $1 $2
   elif [ "$1" == "-u" ] && [ -n "$2" ];
   then
   	umnt $1 $2
   else
   	echo ""
   	echo "Either 1'st, 2'nd or both parameters were missing"
   	echo ""
   	echo "1'st parameter can be one of these: -m(mount) OR -u(umount)"
   	echo "2'nd parameter is the full path of rootfs directory(with trailing '/')"
   	echo ""
   	echo "For example: ch-mount -m /media/sdcard/"
   	echo ""
   	echo 1st parameter : ${1}
   	echo 2nd parameter : ${2}
   fi
   
   

   更改權限：

   sudo chmod +x mount.sh 
   

7. 掛載

   source mount.sh -m ./rootfs/
   

8. 更新軟件

   apt update
   apt install sudo vim kmod net-tools ethtool ifupdown rsyslog htop iputils-ping language-pack-en-base ssh
   

   注意：ssh必須安裝，不然后面鏈接串口服務會出錯

9. 設置用戶名和密碼

   root@zsd-virtual-machine:/# passwd root
   New password: 
   Retype new password: 
   passwd: password updated successfully
   
   root@zsd-virtual-machine:/# adduser zsd 
   New password: 
   Retype new password: 
   `Enter`
   `Enter`
   ......
   `Enter`
   `Enter`
   

10. 設置IP和名稱

    root@zsd-virtual-machine:/# echo "zzssdd2-imx6ull" > /etc/hostname
    root@zsd-virtual-machine:/# echo "127.0.0.1 localhost" >> /etc/hosts
    root@zsd-virtual-machine:/# echo "127.0.0.1 zzssdd2-imx6ull" >> /etc/hosts
    

11. 設置串口終端

    ln -s /lib/systemd/system/getty@.service /etc/systemd/system/getty.target.wants/[e-mail]
    

    注意：

    如果提示報錯提示如下：

    root@zsd-virtual-machine:/# ln -s /lib/systemd/system/getty@.service /etc/systemd/system/getty.target.wants/[e-mail]
    /usr/bin/ln: failed to create symbolic link '/etc/systemd/system/getty.target.wants/[e-mail]': No such file or directory
    

    說明/etc/systemd/system/目錄下沒有getty.target.wants目錄。

    解決方法：安裝ssh會創建該目錄，然后重新執行一遍設置串口終端命令即可。

12. 退出

    #退出qemu模擬器
    exit
    #取消掛載
    source mount.sh -u ./rootfs/
    #打包
    sudo tar -czvf ubuntu-base-20.04.3-rootfs.tar.gz rootfs/*
    

二、Debian 11

• 直接使用三方制作好的Debian根文件系統，比如Linaro
• 使用Multistrap或Debootstrap工具構建自己的Debian根文件系統

下面我使用debootstrap工具構建Debian11根文件系統（別問為什么不用multistrap，問就是不會︶︹︺）

1. 安裝工具

   sudo apt install binfmt-support qemu qemu-user-static debootstrap
   

2. 抽取Debain文件系統

   sudo debootstrap --arch=armhf --foreign bullseye rootfs https://mirrors.tuna.tsinghua.edu.cn/debian/
   

   參數說明：

   arch：CPU架構

   bullseye：debian版本名，這是版本11的名稱

   foreign：在與主機架構不相同時需要指定此參數，僅做初始化的解包

   rootfs：要存放文件系統的文件夾

   https://mirrors.tuna.tsinghua.edu.cn/debian/：下載源，這里使用國內的清華源

   抽取成功后如下：

   $ ls ./rootfs/
   bin   debootstrap  etc   lib   root  sbin  tmp  var
   boot  dev          home  proc  run   sys   usr
   

3. 復制qemu-arm-static到剛構建的基本系統中

   sudo cp /usr/bin/qemu-arm-static ./rootfs/usr/bin
   

4. 完成文件系統引導

   sudo DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true chroot rootfs debootstrap/debootstrap --second-stage
   

   參數說明：

   • chroot rootfs

     更改根目錄為rootfs：就是變更當前進程及其子進程的可見根路徑。變更后，程序無法訪問可見根目錄外文件和命令。

   • DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true

     避免debconf向用戶詢問任何問題（非交互式），相當於是靜默配置安裝。

     了解更多debconf - Debian Wiki

   • debootstrap

     man debootstrap
     或
     debootstrap --help
     

     了解更多Debootstrap - Debian Wiki

   完成后提示如下：

   I: Base system installed successfully.
   

5. 更換下載源

   #備份
   sudo cp ./rootfs/etc/apt/sources.list ./rootfs/etc/apt/sources.list.bak
   #編輯
   sudo vim ./rootfs/etc/apt/sources.list
   
   #換成如下內容:
   
   # 默認注釋了源碼鏡像以提高 apt update 速度，如有需要可自行取消注釋
   deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye main contrib non-free
   # deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye main contrib non-free
   deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-updates main contrib non-free
   # deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-updates main contrib non-free
   
   deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-backports main contrib non-free
   # deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-backports main contrib non-free
   
   deb https://mirrors.tuna.tsinghua.edu.cn/debian-security bullseye-security main contrib non-free
   # deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security bullseye-security main contrib non-free
   

6. 創建掛載腳本vim mount.sh

   內容如下：

   #!/bin/bash
   mnt() {
   	echo "MOUNTING"
   	sudo mount -t proc /proc ${2}proc
   	sudo mount -t sysfs /sys ${2}sys
   	sudo mount -o bind /dev ${2}dev
   	sudo mount -o bind /dev/pts ${2}dev/pts
   	sudo chroot ${2}
   }
   umnt() {
   	echo "UNMOUNTING"
   	sudo umount ${2}proc
   	sudo umount ${2}sys
   	sudo umount ${2}dev/pts
   	sudo umount ${2}dev
   }
   
   if [ "$1" == "-m" ] && [ -n "$2" ] ;
   then
   	mnt $1 $2
   elif [ "$1" == "-u" ] && [ -n "$2" ];
   then
   	umnt $1 $2
   else
   	echo ""
   	echo "Either 1'st, 2'nd or both parameters were missing"
   	echo ""
   	echo "1'st parameter can be one of these: -m(mount) OR -u(umount)"
   	echo "2'nd parameter is the full path of rootfs directory(with trailing '/')"
   	echo ""
   	echo "For example: ch-mount -m /media/sdcard/"
   	echo ""
   	echo 1st parameter : ${1}
   	echo 2nd parameter : ${2}
   fi
   
   

   更改權限：

   sudo chmod +x mount.sh 
   

7. 掛載

   source mount.sh -m ./rootfs/
   

8. 執行以下命令

   # <file system> <mount point> <type> <options> <dump> <pass>
   echo "proc /proc proc defaults 0 0" >> etc/fstab 
   

9. 設置Linux中的locale環境參數

   export LC_ALL=C
   

   如果不設置在后面安裝軟件時會有如下提示：

   perl: warning: Setting locale failed.
   perl: warning: Please check that your locale settings:
   	LANGUAGE = "zh_CN:en_US:en",
   	LC_ALL = (unset),
   	LC_PAPER = "zh_CN.UTF-8",
   	LC_NUMERIC = "zh_CN.UTF-8",
   	LC_IDENTIFICATION = "zh_CN.UTF-8",
   	LC_MEASUREMENT = "zh_CN.UTF-8",
   	LC_NAME = "zh_CN.UTF-8",
   	LC_TELEPHONE = "zh_CN.UTF-8",
   	LC_ADDRESS = "zh_CN.UTF-8",
   	LC_MONETARY = "zh_CN.UTF-8",
   	LC_TIME = "zh_CN.UTF-8",
   	LANG = "zh_CN.UTF-8"
       are supported and installed on your system.
   perl: warning: Falling back to the standard locale ("C").
   /usr/bin/locale: Cannot set LC_CTYPE to default locale: No such file or directory
   /usr/bin/locale: Cannot set LC_MESSAGES to default locale: No such file or directory
   /usr/bin/locale: Cannot set LC_ALL to default locale: No such file or directory
   

10. 安裝軟件

    apt update
    
    apt install sudo
    apt install net-tools
    apt install ethtool 
    apt install htop 
    apt install ssh
    ......
    

11. 設置用戶

    #設置root用戶密碼
    passwd root
    #添加新用戶
    adduser zzssdd2
    

12. 設置以太網

    echo "auto eth0" > /etc/network/interfaces.d/eth0
    echo "iface eth0 inet dhcp" >> /etc/network/interfaces.d/eth0
    

13. 設置IP和名稱

    echo "zzssdd2-imx6ull" > /etc/hostname
    echo "127.0.0.1 localhost" >> /etc/hosts
    echo "127.0.0.1 zzssdd2-imx6ull" >> /etc/hosts
    

14. 退出

    #退出qemu環境
    exit
    # 取消掛載
    source mount.sh -u ./rootfs/
    #打包
    sudo tar -zcvf debian_bullseye-rootfs.tar.gz ./rootfs/*
    

三、Buildroot

Buildroot是一個簡單、高效且易於使用的工具，可以通過交叉編譯生成嵌入式Linux系統。更詳細的了解參考官方手冊The Buildroot user manual

下面使用buildroot-2021.08.1版本對IMX6ULL平台進行配置。

1. 下載：https://buildroot.org/download.html

2. 解壓 ：tar -jxvf buildroot-2021.08.1.tar.bz2

3. 進入圖形配置界面：make menuconfig

   注：下面貼出來的都是經過手動配置更改的選項，沒有貼出來的則表示使用默認設置

4. 配置Target options

   Target options  ---> 
   	Target Architecture (ARM (little endian))
   	Target Binary Format (ELF)
   	Target Architecture Variant (cortex-A7)
   	Target ABI (EABIhf)
   	Floating point strategy (NEON/VFPv4)
   	ARM instruction set (ARM)
   

5. 配置Toolchain

   Toolchain  --->  
   	Toolchain type (External toolchain)
   	Toolchain (Custom toolchain)
   	Toolchain origin (Pre-installed toolchain)
   	(/usr/local/arm/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf) Toolchain path 
   	($(ARCH)-none-linux-gnueabihf) Toolchain prefix 
       External toolchain gcc version (10.x)
       External toolchain kernel headers series (4.20.x)
       External toolchain C library (glibc/eglibc)
       [ ] Toolchain has RPC support? 
       [*] Toolchain has C++ support?
   

6. 配置System configuration

   System configuration  --->
   	(zzssdd2) System hostname 
   	(Hello zzssdd2) System banner
   	/dev management (Dynamic using devtmpfs + mdev) 
   	(root) Root password
   	(eth0) Network interface to configure through DHCP 
   

7. 配置Target packages

   這一步根據自己的需求選擇安裝需要的包即可（這里為了下一步編譯快一些我保持默認選擇）。

8. 按需配置完成后：Save --> Exit --> 執行make命令等待編譯完成后在Buildroot根目錄下的output/images目錄下可以看到編譯好的根文件系統。

   注意：

   1. 如果編譯之前執行過make則需要先執行make clean清理一下再執行make命令，否則可能報錯。
   2. 如果遇到某些包下載巨慢、下不動、下載失敗的情況，可以根據編譯信息提示的地址復制到瀏覽器手動下載。下載下來后將其復制到Buildroot根目錄下的dl目錄下，然后CTRL+C終止編譯 --> make clean清除上次編譯 --> make重新編譯。

四、驗證

參考開發板直連電腦搭建NFS＆TFTP環境第四節