squashfs

安装相关软件

yum install squashfs-tools -y

解压镜像获取squashfs

创建目录

[root@test1 ~]# mkdir -p /mnt/{iso,rootfs}
[root@test1 ~]# mkdir {myiso,squashfs}

挂载镜像

[root@test1 ~]# mount /dev/sr0 /mnt/iso/
mount: /dev/sr0 is write-protected, mounting read-only
[root@test1 ~]#

拷贝镜像内容到本地

[root@test1 ~]# cp -rap /mnt/iso/* myiso/

拷贝squashfs.img 到指定目录并解压

[root@test1 ~]# cp myiso/LiveOS/squashfs.img squashfs/
[root@test1 ~]# cd squashfs/
[root@test1 squashfs]# unsquashfs squashfs.img

挂载rootfs.img

[root@test1 squashfs]# mount squashfs-root/LiveOS/rootfs.img /mnt/rootfs/

测试、修改chroot

测试chroot

[root@test1 ~]# chroot /mnt/rootfs/
bash-4.2#
bash-4.2# echo alvin >> hello.txt
bash-4.2# cat hello.txt
alvin
bash-4.2# ls
bin  dev  etc  firmware  hello.txt  lib  lib64      lost+found  mnt  modules  proc  root  run  sbin  sys  tmp  usr  var
bash-4.2# exit

刚才我们在rootfs里创建了一个文件，现在我们将修改后的内容打包,这里我们打包到为/tmp/squashfs1.img

打包squashfs.img

umount /mnt/rootfs
mksquashfs squashfs-root /tmp/squashfs.img -noappend -all-root

然后我们可以验证一下是squashfs1.img里的rootfs.img，是否是我们修改后的

[root@test1 tmp]# unsquashfs squashfs.img
Parallel unsquashfs: Using 4 processors
1 inodes (16384 blocks) to write

[=========================================================================================================================================================================================================================================================|] 16384/16384 100%

created 1 files
created 2 directories
created 0 symlinks
created 0 devices
created 0 fifos
[root@test1 tmp]# cd squashfs-root/
[root@test1 squashfs-root]# mount LiveOS/rootfs.img /mnt/rootfs/
[root@test1 squashfs-root]# ls /mnt/rootfs/
bin  dev  etc  firmware  lib  lib64  lost+found  mnt  modules  ok  proc  root  run  sbin  sys  tmp  usr  var
[root@test1 squashfs-root]# mksquashfs squashfs-root /tmp/squashfs.img -noappend -all-root

如上所示，我们看到了我们之前创建的那个ok文件。

然后覆盖原镜像

[root@test1 tmp]# cp /tmp/squashfs.img ~/myiso/LiveOS/squashfs.img
cp: overwrite ‘/root/myiso/LiveOS/squashfs.img’? y

打包新的镜像

[root@test1 tmp]# cd
[root@test1 ~]# mkisofs -o alvin_custom.iso -input-charset utf-8 -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -R -J -v -T -joliet-long /root/myiso/