utils/watchcat/files/watchcat.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (C) 2010 segal.di.ubi.pt
   4 #
   5 # This is free software, licensed under the GNU General Public License v2.
   6 #
   7
   8 mode="$1"
   9
  10 # Fix potential typo in mode (backward compatibility).
  11 [ "$mode" = "allways" ] && mode="always"
  12
  13 shutdown_now() {
  14         local forcedelay="$1"
  15
  16         reboot &
  17
  18         [ "$forcedelay" -ge 1 ] && {
  19                 sleep "$forcedelay"
  20
  21                 echo b > /proc/sysrq-trigger # Will immediately reboot the system without syncing or unmounting your disks.
  22         }
  23 }
  24
  25 watchcat_always() {
  26         local period="$1"; local forcedelay="$2"
  27
  28         sleep "$period" && shutdown_now "$forcedelay"
  29 }
  30
  31 watchcat_ping() {
  32         local period="$1"; local forcedelay="$2"; local pinghosts="$3"; local pingperiod="$4"
  33
  34         time_now="$(cat /proc/uptime)"
  35         time_now="${time_now%%.*}"
  36         time_lastcheck="$time_now"
  37         time_lastcheck_withinternet="$time_now"
  38
  39         while true
  40         do
  41                 # account for the time ping took to return. With a ping time of 5s, ping might take more than that, so it is important to avoid even more delay.
  42                 time_now="$(cat /proc/uptime)"
  43                 time_now="${time_now%%.*}"
  44                 time_diff="$((time_now-time_lastcheck))"
  45
  46                 [ "$time_diff" -lt "$pingperiod" ] && {
  47                         sleep_time="$((pingperiod-time_diff))"
  48                         sleep "$sleep_time"
  49                 }
  50
  51                 time_now="$(cat /proc/uptime)"
  52                 time_now="${time_now%%.*}"
  53                 time_lastcheck="$time_now"
  54
  55                 for host in "$pinghosts"
  56                 do
  57                         if ping -c 1 "$host" &> /dev/null
  58                         then
  59                                 time_lastcheck_withinternet="$time_now"
  60                         else
  61                                 time_diff="$((time_now-time_lastcheck_withinternet))"
  62                                 logger -p daemon.info -t "watchcat[$$]" "no internet connectivity for $time_diff seconds. Reseting when reaching $period"
  63                         fi
  64                 done
  65
  66                 time_diff="$((time_now-time_lastcheck_withinternet))"
  67                 [ "$time_diff" -ge "$period" ] && shutdown_now "$forcedelay"
  68
  69         done
  70 }
  71
  72         if [ "$mode" = "always" ]
  73         then
  74                 watchcat_always "$2" "$3"
  75         else
  76                 watchcat_ping "$2" "$3" "$4" "$5"
  77         fi