package/kexec-tools/files/kreboot

   1 #!/bin/sh
   2
   3 ARCH=$(uname -m)
   4 KERNEL="/mnt/boot/kernel"
   5 KEXEC_ARGS="-l"
   6 if [ $ARCH = "arm" ]; then
   7   KEXEC_ARGS="$KEXEC_ARGS --atags"
   8 fi
   9 PART_A=2
  10 PART_B=3
  11 me=$0
  12
  13 usage() {
  14 cat >&2 <<EOF
  15 Syntax: $me [-k kernel]
  16
  17  -k     give the path to the kernel eg. /boot/vmlinuz-4.7.4
  18         (default: $KERNEL)
  19 EOF
  20   exit $1
  21 }
  22
  23 while getopts "k:" ch; do
  24   case $ch {
  25   (k)
  26     # if default does not fit, give the actual keren via -k otion eg "-k /boot/vmlinuz-4.7.4
  27     KERNEL="$OPTARG"
  28   ;;
  29
  30   (*)
  31     usage 1
  32   ;;
  33   }
  34 done
  35 shift $((OPTIND - 1))
  36
  37
  38 load_kernel(){
  39   # get the Bootargs and replace the current Partition with
  40   # the one in $1 e.g. replace /dev/mmcblk0p2 with /dev/mmcblk0p3
  41   BOOT_ARGS="$(cat /proc/cmdline | sed s#$CURRENT_PART#$1#g)"
  42   # echo "kexec $KEXEC_ARG --append=\"$BOOT_ARGS\" $KERNEL"
  43   # set -x
  44   # Load the new kernel, unmount the partition and exec the new kernel
  45   kexec $KEXEC_ARGS --append=\""$BOOT_ARGS"\" $KERNEL
  46   umount /mnt
  47   kexec -e
  48 }
  49
  50 # just to be sure
  51 umount /mnt 2> /dev/null
  52
  53 # get the partiton of the current kernel
  54 PART="/dev/$(readlink /dev/root)"
  55 # extract the partition number
  56 C_M_PART_NUM=$(readlink /dev/root | grep -o -e '[[:digit:]]*$')
  57
  58 # cut off the Partition Number
  59 C_M_PART=$(readlink /dev/root | sed "s/$C_M_PART_NUM\$//")
  60
  61 CURRENT_PART="/dev/${C_M_PART}${C_M_PART_NUM}"
  62
  63 case $C_M_PART_NUM in
  64   "$PART_A")
  65     DEVICE="/dev/${C_M_PART}${PART_B}"
  66     mount -r $DEVICE /mnt
  67     load_kernel $DEVICE
  68   ;;
  69   "$PART_B")
  70     DEVICE="/dev/${C_M_PART}${PART_A}"
  71     mount -r $DEVICE /mnt
  72     load_kernel $DEVICE
  73   ;;
  74   *)
  75     echo "FAILURE"
  76   ;;
  77 esac