gcc/lock-and-run.sh

   1 #! /bin/sh
   2 # Shell-based mutex using mkdir.
   3
   4 lockdir=$1 prog=$2; shift 2 || exit 1
   5 count=0
   6 # Remember when we started trying to acquire the lock.
   7 touch lock-stamp.$$
   8 trap 'rm -r "$lockdir" lock-stamp.$$' 0
   9 until mkdir "$lockdir" 2>/dev/null; do
  10     # Say something periodically so the user knows what's up.
  11     if [ `expr $count % 30` = 0 ]; then
  12         # Reset if the lock has been renewed.
  13         if [ -n "`find \"$lockdir\" -newer lock-stamp.$$`" ]; then
  14             touch lock-stamp.$$
  15             count=1
  16         # Steal the lock after 5 minutes.
  17         elif [ $count = 300 ]; then
  18             echo removing stale $lockdir >&2
  19             rm -r "$lockdir"
  20         else
  21             echo waiting to acquire $lockdir >&2
  22         fi
  23     fi
  24     sleep 1
  25     count=`expr $count + 1`
  26 done
  27 echo $prog "$@"
  28 $prog "$@"
  29 # The trap runs on exit.