src/vlock.sh

   1 #!%BOURNE_SHELL%
   2 #
   3 # vlock.sh -- start script for vlock, the VT locking program for linux
   4 #
   5 # This program is copyright (C) 2007 Frank Benkstein, and is free
   6 # software which is freely distributable under the terms of the
   7 # GNU General Public License version 2, included as the file COPYING in this
   8 # distribution.  It is NOT public domain software, and any
   9 # redistribution not permitted by the GNU General Public License is
  10 # expressly forbidden without prior written permission from
  11 # the author.
  12
  13 # Ignore some signals.
  14 trap : HUP INT QUIT TSTP
  15
  16 # Exit on error.
  17 set -e
  18
  19 # Magic characters to clear the terminal.
  20 CLEAR_SCREEN="`echo -e '\033[H\033[J'`"
  21
  22 # Enter message that is common to different the messages.
  23 VLOCK_ENTER_PROMPT="Please press [ENTER] to unlock."
  24
  25 # Message that is displayed when console switching is disabled.
  26 VLOCK_ALL_MESSAGE="${CLEAR_SCREEN}\
  27 The entire console display is now completely locked.
  28 You will not be able to switch to another virtual console.
  29
  30 ${VLOCK_ENTER_PROMPT}"
  31
  32 # Message that is displayed when only the current terminal is locked.
  33 VLOCK_CURRENT_MESSAGE="${CLEAR_SCREEN}\
  34 This TTY is now locked.
  35
  36 ${VLOCK_ENTER_PROMPT}"
  37
  38 # Read user settings.
  39 if [ -r "${HOME}/.vlockrc" ] ; then
  40   . "${HOME}/.vlockrc"
  41 fi
  42
  43 # "Compile" time variables.
  44 VLOCK_MAIN="%PREFIX%/sbin/vlock-main"
  45 VLOCK_VERSION="%VLOCK_VERSION%"
  46 # If set to "y" plugin support is enabled in vlock-main.
  47 VLOCK_ENABLE_PLUGINS="%VLOCK_ENABLE_PLUGINS%"
  48
  49 print_help() {
  50   echo >&2 "vlock: locks virtual consoles, saving your current session."
  51   if [ "${VLOCK_ENABLE_PLUGINS}" = "yes" ] ; then
  52     echo >&2 "Usage: vlock [options] [plugins...]"
  53   else
  54     echo >&2 "Usage: vlock [options]"
  55   fi
  56   echo >&2 "       Where [options] are any of:"
  57   echo >&2 "-c or --current: lock only this virtual console, allowing user to"
  58   echo >&2 "       switch to other virtual consoles."
  59   echo >&2 "-a or --all: lock all virtual consoles by preventing other users"
  60   echo >&2 "       from switching virtual consoles."
  61   if [ "${VLOCK_ENABLE_PLUGINS}" = "yes" ] ; then
  62     echo >&2 "-n or --new: allocate a new virtual console before locking,"
  63     echo >&2 "       implies --all."
  64     echo >&2 "-s or --disable-sysrq: disable SysRq while consoles are locked to"
  65     echo >&2 "       prevent killing vlock with SAK"
  66     echo >&2 "-t <seconds> or --timeout <seconds>: run screen saver plugins"
  67     echo >&2 "       after the given amount of time."
  68   fi
  69   echo >&2 "-v or --version: Print the version number of vlock and exit."
  70   echo >&2 "-h or --help: Print this help message and exit."
  71 }
  72
  73 # Export variables only if they are set.  Some shells create an empty variable
  74 # on export even if it was previously unset.
  75 export_if_set() {
  76   while [ $# -gt 0 ] ; do
  77     if ( eval [ "\"\${$1+set}\"" = "set" ] ) ; then
  78       eval export $1
  79     fi
  80     shift
  81   done
  82 }
  83
  84 main() {
  85   short_options_with_arguments="t"
  86   long_options_with_arguments="timeout"
  87
  88   # Parse command line arguments.
  89   while [ $# -gt 0 ] ; do
  90     case "$1" in
  91       -[!-]?*)
  92         # Strip "-" to get the list of option characters.
  93         options="${1#-}"
  94         shift
  95
  96         last_option_argument="${options}"
  97         last_option_index=0
  98
  99         # If an option character takes an argument all characters after it
 100         # become the argument if it isn't already the last one.  E.g. if "x"
 101         # takes an argument "-fooxbar" becomes "-foo -x bar".
 102         while [ -n "${last_option_argument}" ] ; do
 103           # Get first option character.
 104           option="$(expr "${last_option_argument}" : '\(.\)')"
 105           # Strip it from the list of option characters.
 106           last_option_argument="${last_option_argument#?}"
 107           last_option_index=$((${last_option_index} + 1))
 108
 109           if expr "${short_options_with_arguments}" : "${option}" >/dev/null ; then
 110             # Prepend "-" plus option character and rest of option string to $@.
 111             set -- "-${option}" "${last_option_argument}" "$@"
 112
 113             # Remove all characters after the option character.
 114             if [ "${last_option_index}" -gt 1 ] ; then
 115               options="$(expr "${options}" : "\(.\{$((${last_option_index}-1))\}\)")"
 116             else
 117               options=""
 118             fi
 119
 120             break
 121           fi
 122         done
 123
 124         # Convert clashed arguments like "-foobar" to "-f -o -o -b -a -r".
 125         while [ -n "${options}" ] ; do
 126           # Get last option character.
 127           option="$(expr "${options}" : '.*\(.\)')"
 128           # Strip it from the list of option characters.
 129           options="${options%?}"
 130           # Prepend "-" plus option character to $@.
 131           set -- "-${option}" "$@"
 132         done
 133       ;;
 134       --?*=?*)
 135         # Extract option name and argument.
 136         option="$(expr "x$1" : 'x--\([^=]*\)=.*')"
 137         option_argument="$(expr "x$1" : 'x--[^=]*=\(.*\)')"
 138         shift
 139
 140         compare_options="${long_options_with_arguments}"
 141
 142         # Find the option in the list of options that take an argument.
 143         while [ -n "${compare_options}" ] ; do
 144           compare_option="${compare_options%%,*}"
 145           compare_options="${compare_options#"${compare_option}"}"
 146           compare_options="${compare_options#,}"
 147
 148           if [ "${option}" = "${compare_option}" ] ; then
 149             set -- "--${option}" "${option_argument}" "$@"
 150             unset option option_argument
 151             break
 152           fi
 153         done
 154
 155         if [ -n "${option}" ] ; then
 156           echo >&2 "$0: option '--${option}' does not allow an argument"
 157           exit 1
 158         fi
 159       ;;
 160       -a|--all)
 161         plugins="${plugins} all"
 162         shift
 163         ;;
 164       -c|--current)
 165         unset plugins
 166         shift
 167         ;;
 168       -n|--new)
 169         plugins="${plugins} new"
 170         shift
 171         ;;
 172       -s|--disable-sysrq)
 173         plugins="${plugins} nosysrq"
 174         shift
 175         ;;
 176       -t|--timeout)
 177         VLOCK_TIMEOUT="$2"
 178         if ! shift 2 ; then
 179           echo >&2 "$0: option '$1' requires an argument"
 180           exit 1
 181         fi
 182         ;;
 183       -h|--help)
 184        print_help
 185        exit
 186        ;;
 187       -v|--version)
 188         if [ "${VLOCK_ENABLE_PLUGINS}" = "yes" ] ; then
 189           echo >&2 "vlock version ${VLOCK_VERSION}"
 190         else
 191           echo >&2 "vlock version ${VLOCK_VERSION} (no plugin support)"
 192         fi
 193         exit
 194         ;;
 195       -[!-]|--?*)
 196         echo >&1 "$0: unknown option '$1'"
 197         print_help
 198         exit 1
 199       ;;
 200       --)
 201         # End of option list.
 202         shift
 203         break
 204         ;;
 205       *)
 206         for argument ; do
 207           if [ "${argument}" = "--" ] ; then
 208             has_double_dash="yes"
 209             break
 210           fi
 211         done
 212
 213         if [ -n "${has_double_dash}" ] ; then
 214           set -- "$@" "$1"
 215         else
 216           set -- "$@" -- "$1"
 217         fi
 218
 219         shift
 220         ;;
 221     esac
 222   done
 223
 224   # Export variables for vlock-main.
 225   export_if_set VLOCK_TIMEOUT VLOCK_PROMPT_TIMEOUT
 226   export_if_set VLOCK_MESSAGE VLOCK_ALL_MESSAGE VLOCK_CURRENT_MESSAGE
 227
 228   if [ "${VLOCK_ENABLE_PLUGINS}" = "yes" ] ; then
 229     exec "${VLOCK_MAIN}" ${plugins} ${VLOCK_PLUGINS} "$@"
 230   else
 231     exec "${VLOCK_MAIN}" ${plugins}
 232   fi
 233 }
 234
 235 main "$@"