usr_bin/grml-screen

   1 #!/bin/dash
   2 # Filename:      grml-screen
   3 # Purpose:       wrapper for screen to start with appropriate configuration
   4 # Authors:       grml-team (grml.org), (c) Michael Prokop <mika@grml.org>
   5 # Bug-Reports:   see http://grml.org/bugs/
   6 # License:       This file is licensed under the GPL v2.
   7 ################################################################################
   8
   9 # export variable USER for use withing GNU screen:
  10   export USER=`id -un`
  11
  12 # fix tty permissions
  13   TTY=`tty`
  14   sudo chmod 660       $TTY
  15   sudo chown $USER.tty $TTY
  16
  17 # FIXME: fix for screen race-conditions
  18 PID_FILE_="/var/lock/grml-screen"
  19 PID_FILE_CREATED_="false"
  20 MY_PID_="$$"
  21 if [ ! -d "/var/run/screen/S-$USER" ]; then
  22     # no /var/run/screen/S-$USER and possible no /var/run/screen either -> locking
  23     for i in `seq 40`; do   # 40*0.25 = 10 seconds
  24         if lockfile-create --retry 0 $PID_FILE_; then
  25             echo $MY_PID_ >$PID_FILE_
  26             PID_FILE_CREATED_="true"
  27             break
  28         else
  29             PID_FILE_CREATED_="error"
  30         fi
  31         sleep 0.25
  32     done
  33 fi
  34 if [ $PID_FILE_CREATED_ = "true" ]; then
  35     # FORK BEGIN
  36     (
  37         for i in `seq 40`; do   # 40*0.25 = 10 seconds
  38             if [ ! -d "/var/run/screen/S-$USER" ]; then
  39                 sleep 0.25  # educated guess
  40             else
  41                 break
  42             fi
  43         done
  44         if [ `cat $PID_FILE_` = $MY_PID_ ]; then
  45             rm $PID_FILE_
  46             lockfile-remove $PID_FILE_
  47         fi
  48     )&
  49     # FORK END
  50 elif [ $PID_FILE_CREATED_ = "error" ]; then
  51     SLEEP_TIME_="$(( $$ % 5 * 5 + 5 ))"
  52     echo "grml-screen: Error could not create lockfile! (sleeping for $SLEEP_TIME_)" >&2
  53     sleep $SLEEP_TIME_
  54 elif [ $PID_FILE_CREATED_ = "false" ]; then
  55     echo "nothing to do" &>/dev/null
  56 else
  57     echo "grml-screen: internal error - PID_FILE_CREATED_ == \"$PID_FILE_CREATED_\"" >&2
  58 fi
  59
  60 # now run screen with config
  61   cd $HOME     # important for e.g. hardcopy-feature
  62
  63   if [ `id -u` = 0 ] ; then
  64     exec screen -U -c /etc/grml/screenrc
  65   elif [ -r "$HOME/.screenrc" ] ; then
  66     exec screen -U -c "$HOME/.screenrc"
  67   else
  68     exec screen -U -c /etc/grml/screenrc_grml
  69   fi
  70
  71 ## END OF FILE #################################################################