#!/bin/sh
. /root/idle_disks.conf

log() {
   time=$(date '+%b %e %H:%M:%S')
   echo "$time: $*" >> $LOG_FILE
}

vlog() {
   if [ $VERBOSE -gt 0 ]; then
      log $@
   fi
}

usbid() {
   # Find the USB IDs for a given sdX.
   # If the disk is not USB, these values will be empty
   vid=$(cat /sys/block/$1/device/../../../../idVendor  2>/dev/null)
   pid=$(cat /sys/block/$1/device/../../../../idProduct 2>/dev/null)
}

rm $STATUS_DIR/sd[a-z].stat 2>/dev/null
rm $STATUS_DIR/sd[a-z].idlecount 2>/dev/null

cd /dev
while [ true ]; do
   for disk in sd[a-z]; do

      # Check if it is a USB disk, and if it is in a whitelist
      usbid $disk
      grep -q "^$pid" $WHITELIST/$vid 2>/dev/null
      if [ $? -eq 0 ]; then
         stat_file=$STATUS_DIR/$disk.stat
         count_file=$STATUS_DIR/$disk.idlecount

         newstat=$(cat /sys/block/$disk/stat 2>/dev/null)
         curstat=$(cat $stat_file 2>/dev/null)
         count=$(cat $count_file 2>/dev/null)

         if [ "$newstat" != "$curstat" ]; then
            # The status did change, get back to default timeout
            echo "$newstat" > $stat_file
            echo $((TIMEOUT*6)) > $count_file
            if [ "$count" -eq 0 ]; then
               log "/dev/$disk: new activity detected"
            fi
         else
            if [ $count -gt 1 ]; then
               # Decrement the idlecounter, since the status did not change
               echo $(($count-1)) > $count_file
            else
               if [ $count -eq 1 ]; then
                  # If the idle counter is at 1, lets stop the disk
                  sync
                  scsi-stop /dev/$disk
                  log "/dev/$disk: spinned down"

                  # After the sync, the I/O stat has changed. Update it.
                  cp /sys/block/$disk/stat $stat_file
                  echo 0 > $count_file
               fi
            fi
         fi
      else
         # Some debugging messages
         if [ "$vid" -a "$pid" ]; then
            vlog "/dev/$disk: ignored (USB ID $vid:$pid not in whitelist)"
         else
            vlog "/dev/$disk: ignored (not an USB device)"
         fi
      fi
   done

   sleep 10
done