mkinitrd.sh

   1 #!/bin/bash
   2 #
   3 # mkinitrd.sh: Shell script to make an initial initrd image
   4 # by Jose V Beneyto, sepen at crux dot nu
   5
   6 CONFIG_SHELL=/bin/bash
   7
   8 msgUsage() {
   9   echo "Usage: $APPNAME <options>"
  10   echo "Where options are:"
  11   echo "  --name=NAME   Name for the result image (default: initrd.gz)"
  12   echo "  --size=SIZE   Size expecified in bytes (default: 4096)"
  13   echo "  --type=TYPE   Filesystem type for the image (default: ext2)"
  14   echo "Example:"
  15   echo "  $APPNAME --name=myinitrd.gz --size=8192"
  16   exit 0
  17 }
  18
  19 msgError() {
  20   echo "Error, $@" 2>&1
  21   exit 1
  22 }
  23
  24 checkRoot() {
  25   [ "$(id -u)" != "0" ] && msgError "you need to be root to do this."
  26 }
  27
  28 parseArgs() {
  29   [ $# -lt 1 ] && msgUsage
  30   for arg in $@; do
  31     case $arg in
  32       --name=*) IMG_NAME=${arg##*=} ;;
  33       --size=*) IMG_SIZE=${arg##*=} ;;
  34       --type=*) IMG_TYPE=${arg##*=} ;;
  35       *) msgUsage ;;
  36     esac
  37   done
  38 }
  39
  40 main() {
  41   rm -rf $TMP_PATH $MNT_PATH
  42   install -d $TMP_PATH $MNT_PATH
  43   pushd $TMP_PATH && \
  44   rm -f initrd
  45   dd if=/dev/zero of=initrd bs=1024 count=$IMG_SIZE && \
  46   mkfs.$IMG_TYPE -F -m 0 -b 1024 initrd $IMG_SIZE && \
  47   mount -v -o loop -t $IMG_TYPE initrd $MNT_PATH && \
  48   rm -rf $MNT_PATH/lost+found && \
  49   install -d -m 0755 $MNT_PATH/{mnt,media,etc,dev,sys,proc,lib,usr,var/{log,lock,run},tmp} && \
  50   mknod $MNT_PATH/dev/console c 5 1 && chmod 666 $MNT_PATH/dev/console && \
  51   mknod $MNT_PATH/dev/null c 1 3 && chmod 666 $MNT_PATH/dev/null && \
  52   mknod $MNT_PATH/dev/tty c 5 0 && chmod 666 $MNT_PATH/dev/tty && \
  53   mkdir $MNT_PATH/dev/rd && mknod $MNT_PATH/dev/rd/0 b 1 0
  54   mknod $MNT_PATH/dev/ram0 b 1 0 && chmod 600 $MNT_PATH/dev/ram0
  55   for i in 0 1 2 3 4 5 6 7; do
  56     mknod $MNT_PATH/dev/tty$i c 4 $i && chmod 666 $MNT_PATH/dev/tty$i
  57   done && \
  58   umount -v $MNT_PATH && \
  59   gzip -v initrd && \
  60   popd && \
  61   mv $TMP_PATH/initrd.gz $IMG_NAME
  62 }
  63
  64 APPNAME="$(basename $0)"
  65
  66 TMP_PATH="$(cd $(dirname $APPNAME); pwd)/.tmp"
  67 MNT_PATH="$(cd $(dirname $APPNAME); pwd)/.mnt"
  68
  69 IMG_SIZE=4096       # default image size = 4MB
  70 IMG_TYPE=ext2       # default filesystem type = ext2
  71
  72 export PATH=$PATH:/sbin:/usr/sbin
  73
  74 checkRoot
  75 parseArgs $@ && \
  76 main || msgError "$APPNAME failed"
  77
  78 umount -v $MNT_PATH
  79 rm -rf $TMP_PATH $MNT_PATH
  80
  81 # End of file