INSTALL/CreatePersistentImg.sh

   1 #!/bin/sh
   2
   3 size=1024
   4 fstype=ext4
   5 label=casper-rw
   6 config=''
   7
   8 print_usage() {
   9     echo 'Usage:  CreatePersistentImg.sh [ -s size ] [ -t fstype ] [ -l LABEL ] [ -c CFG ]'
  10     echo '  OPTION: (optional)'
  11     echo '   -s size in MB, default is 1024'
  12     echo '   -t filesystem type, default is ext4  ext2/ext3/ext4/xfs are supported now'
  13     echo '   -l label, default is casper-rw'
  14     echo '   -c configfile name inside the persistence file. File content is "/ union"'
  15     echo ''
  16 }
  17
  18 while [ -n "$1" ]; do
  19     if [ "$1" = "-s" ]; then
  20         shift
  21         size=$1
  22     elif [ "$1" = "-t" ]; then
  23         shift
  24         fstype=$1
  25     elif [ "$1" = "-l" ]; then
  26         shift
  27         label=$1
  28     elif [ "$1" = "-c" ]; then
  29         shift
  30         config=$1
  31     elif [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
  32         print_usage
  33         exit 0
  34     else
  35         print_usage
  36         exit 1
  37     fi
  38     shift
  39 done
  40
  41
  42 # check label
  43 if [ -z "$label" ]; then
  44     echo "The label can NOT be empty."
  45     exit 1
  46 fi
  47
  48 # check size
  49 if echo $size | grep -q "^[0-9][0-9]*$"; then
  50     if [ $size -le 1 ]; then
  51         echo "Invalid size $size"
  52         exit 1
  53     fi
  54 else
  55     echo "Invalid size $size"
  56     exit 1
  57 fi
  58
  59
  60 # check file system type
  61 # nodiscard must be set for ext2/3/4
  62 # -K must be set for xfs
  63 if echo $fstype | grep -q '^ext[234]$'; then
  64     fsopt='-E nodiscard'
  65 elif [ "$fstype" = "xfs" ]; then
  66     fsopt='-K'
  67 else
  68     echo "unsupported file system $fstype"
  69     exit 1
  70 fi
  71
  72 # 00->ff avoid sparse file
  73 dd if=/dev/zero  bs=1M count=$size | tr '\000' '\377' > persistence.dat
  74 sync
  75
  76 freeloop=$(losetup -f)
  77
  78 losetup $freeloop persistence.dat
  79
  80 mkfs -t $fstype $fsopt -L $label $freeloop
  81
  82 sync
  83
  84 if [ -n "$config" ]; then
  85     if [ -d ./persist_tmp_mnt ]; then
  86         rm -rf ./persist_tmp_mnt
  87     fi
  88
  89     mkdir ./persist_tmp_mnt
  90     if mount $freeloop ./persist_tmp_mnt; then
  91         echo '/ union' > ./persist_tmp_mnt/$config
  92         sync
  93         umount ./persist_tmp_mnt
  94     fi
  95     rm -rf ./persist_tmp_mnt
  96 fi
  97
  98 losetup -d $freeloop