INSTALL/CreatePersistentImg.sh

   1 #!/bin/sh
   2
   3 size=1024
   4 fstype=ext4
   5 label=casper-rw
   6 config=''
   7 outputfile=persistence.dat
   8
   9 print_usage() {
  10     echo 'Usage:  CreatePersistentImg.sh [ -s size ] [ -t fstype ] [ -l LABEL ] [ -c CFG ]'
  11     echo '  OPTION: (optional)'
  12     echo '   -s size in MB, default is 1024'
  13     echo '   -t filesystem type, default is ext4  ext2/ext3/ext4/xfs are supported now'
  14     echo '   -l label, default is casper-rw'
  15     echo '   -c configfile name inside the persistence file. File content is "/ union"'
  16     echo '   -o outputfile name, default is persistence.dat'
  17     echo ''
  18 }
  19
  20 while [ -n "$1" ]; do
  21     if [ "$1" = "-s" ]; then
  22         shift
  23         size=$1
  24     elif [ "$1" = "-t" ]; then
  25         shift
  26         fstype=$1
  27     elif [ "$1" = "-l" ]; then
  28         shift
  29         label=$1
  30     elif [ "$1" = "-c" ]; then
  31         shift
  32         config=$1
  33     elif [ "$1" = "-o" ]; then
  34         shift
  35         outputfile=$1
  36     elif [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
  37         print_usage
  38         exit 0
  39     else
  40         print_usage
  41         exit 1
  42     fi
  43     shift
  44 done
  45
  46
  47 # check label
  48 if [ -z "$label" ]; then
  49     echo "The label can NOT be empty."
  50     exit 1
  51 fi
  52
  53 # check size
  54 if echo $size | grep -q "^[0-9][0-9]*$"; then
  55     if [ $size -le 1 ]; then
  56         echo "Invalid size $size"
  57         exit 1
  58     fi
  59 else
  60     echo "Invalid size $size"
  61     exit 1
  62 fi
  63
  64
  65 # check file system type
  66 # nodiscard must be set for ext2/3/4
  67 # -K must be set for xfs
  68 if echo $fstype | grep -q '^ext[234]$'; then
  69     fsopt='-E nodiscard'
  70 elif [ "$fstype" = "xfs" ]; then
  71     fsopt='-K'
  72 else
  73     echo "unsupported file system $fstype"
  74     exit 1
  75 fi
  76
  77 if [ "$outputdir" != "persistence.dat" ]; then
  78     mkdir -p "$(dirname "$outputfile")"
  79 fi
  80
  81 # 00->ff avoid sparse file
  82 dd if=/dev/zero  bs=1M count=$size | tr '\000' '\377' > "$outputfile"
  83 sync
  84
  85 freeloop=$(losetup -f)
  86
  87 losetup $freeloop "$outputfile"
  88
  89 mkfs -t $fstype $fsopt -L $label $freeloop
  90
  91 sync
  92
  93 if [ -n "$config" ]; then
  94     if [ -d ./persist_tmp_mnt ]; then
  95         rm -rf ./persist_tmp_mnt
  96     fi
  97
  98     mkdir ./persist_tmp_mnt
  99     if mount $freeloop ./persist_tmp_mnt; then
 100         echo '/ union' > ./persist_tmp_mnt/$config
 101         sync
 102         umount ./persist_tmp_mnt
 103     fi
 104     rm -rf ./persist_tmp_mnt
 105 fi
 106
 107 losetup -d $freeloop