config/chroot_local-includes/usr/local/sbin/udev-watchdog-wrapper

   1 #!/bin/sh
   2
   3 set -e
   4
   5 ### Helper functions
   6
   7 # For whatever reason, the initscript that calls us sets a pretty scarse $PATH
   8 PATH="/usr/bin:${PATH}"
   9
  10 ### Helper functions
  11
  12 using_fromiso() {
  13         grep -qs -w -E '(fromiso|isofrom)=' /proc/cmdline
  14 }
  15
  16 # Returns the boot device's path in a form that can be passed to the
  17 # eject command, e.g. /dev/scd0 or /dev/block/NN:MM.
  18 boot_device() {
  19         if using_fromiso ; then
  20         # When booting with e.g. fromiso=/dev/sdx3/tails-XXX.iso, a loop device
  21         # is mounted onto /live/image => we cannot get the boot device from there.
  22         # This loop device's backing file is seen by the system as
  23         # /isofrom/XXX.iso, which is not available presumably because pivotroot
  24         # was run => we cannot get the boot device from there either.
  25         # Instead, we parse fromiso='s argument the same way live-boot does
  26         # in order to extract the device path (/dev/sdx3)
  27                 for ARGUMENT in $(cat /proc/cmdline) ; do
  28                         case "${ARGUMENT}" in
  29                                 isofrom=*|fromiso=*)
  30                                         FROMISO="${ARGUMENT#*=}"
  31                                         ;;
  32                         esac
  33                 done
  34                 echo $(dirname "$FROMISO")
  35         else
  36         # Refactorer, beware: the rest of this script depends on the fact that
  37         # the path returned in this case is suitable to be passed as an argument
  38         # to --path in "udevadm info --query" commands... which is not the case
  39         # of paths in the /dev/sdxN form.
  40                 DEV_NUMBER="$(udevadm info --device-id-of-file=/live/image)"
  41                 echo "/dev/block/$DEV_NUMBER"
  42         fi
  43 }
  44
  45 # First clean the screen, then brutally shutdown the machine.
  46 do_stop() {
  47         /etc/init.d/gdm3 stop 2>&1 >/dev/null || true
  48         /etc/init.d/kexec-load stop 2>&1 >/dev/null || true
  49         /etc/init.d/tails-kexec stop 2>&1 >/dev/null || true
  50 }
  51
  52
  53 ### Main
  54
  55 BOOT_DEVICE=$(boot_device)
  56
  57 # Assign to QUERY_SELECTOR an option that can be passed as a query selector
  58 # to udevadm info --query commands.
  59 if using_fromiso ; then
  60         DEV_NAME=$(basename "$BOOT_DEVICE")
  61         QUERY_SELECTOR="--name $DEV_NAME"
  62 else
  63         QUERY_SELECTOR="--path $BOOT_DEVICE"
  64 fi
  65
  66 DEV_UDEV_PATH=$(udevadm info --query path     $QUERY_SELECTOR)
  67 DEV_TYPE_LINE=$(udevadm info --query property $QUERY_SELECTOR | grep -w '^ID_TYPE')
  68 DEV_TYPE="${DEV_TYPE_LINE#*=}"
  69
  70 # If the world was sane we'd want to *disable* the eject lock, but it turns out
  71 # that blocks the block events so udev-watchdog never receives the "change"
  72 # event. See [[bugs/sdmem_on_eject_broken_for_CD]].
  73 if [ "$DEV_TYPE" = "cd" ]; then
  74         eject -i on "${BOOT_DEVICE}"
  75 fi
  76
  77 # Start udev-watchdog and stop on clean exit.
  78 /usr/local/sbin/udev-watchdog "$DEV_UDEV_PATH" "$DEV_TYPE" && do_stop