#!/bin/sh
#---------------------------------------------
#   xdg-su
#
#   Utility script to run a command as an alternate user, generally
#       the root user, with a graphical prompt for the root
#       password if needed
#
#   Refer to the usage() function below for usage.
#
#   Copyright 2006, Jeremy White <jwhite@codeweavers.com>
#   Copyright 2006, Kevin Krammer <kevin.krammer@gmx.at>
#
#   LICENSE:
#
#   Permission is hereby granted, free of charge, to any person obtaining a
#   copy of this software and associated documentation files (the "Software"),
#   to deal in the Software without restriction, including without limitation
#   the rights to use, copy, modify, merge, publish, distribute, sublicense,
#   and/or sell copies of the Software, and to permit persons to whom the
#   Software is furnished to do so, subject to the following conditions:
#
#   The above copyright notice and this permission notice shall be included
#   in all copies or substantial portions of the Software.
#
#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
#   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
#   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
#   OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
#   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
#   OTHER DEALINGS IN THE SOFTWARE.
#
#---------------------------------------------

manualpage()
{
cat << _MANUALPAGE
Name

xdg-su - run a GUI program as root after prompting for the root password

Synopsis

xdg-su [-u user] -c command

xdg-su { --help | --manual | --version }

Description

xdg-su provides a graphical dialog that prompts the user for a password to run
command as user or as root if no user was specified.

xdg-su is for use inside a desktop session only.

xdg-su discards any stdout and stderr output from command.

Options

-u user
    run command as user. The default is to run as root.
--help
    Show command synopsis.
--manual
    Show this manualpage.
--version
    Show the xdg-utils version information.

Exit Codes

An exit code of 0 indicates success while a non-zero exit code indicates
failure. The following failure codes can be returned:

1
    Error in command line syntax.
2
    One of the files passed on the command line did not exist.
3
    A required tool could not be found.
4
    The action failed.

See Also

su(1)

Examples

xdg-su -u root -c "/opt/shinythings/bin/install-GUI --install fast"

Runs the /opt/shinythings/bin/install-GUI command with root permissions.

_MANUALPAGE
}

usage()
{
cat << _USAGE
xdg-su - run a GUI program as root after prompting for the root password

Synopsis

xdg-su [-u user] -c command

xdg-su { --help | --manual | --version }

_USAGE
}

#@xdg-utils-common@

#----------------------------------------------------------------------------
#   Common utility functions included in all XDG wrapper scripts
#----------------------------------------------------------------------------

DEBUG()
{
  [ ${XDG_UTILS_DEBUG_LEVEL-0} -lt $1 ] && return 0;
  shift
  echo "$@" >&2
}

#-------------------------------------------------------------
# Exit script on successfully completing the desired operation

exit_success()
{
    if [ $# -gt 0 ]; then
        echo "$@"
        echo
    fi

    exit 0
}


#-----------------------------------------
# Exit script on malformed arguments, not enough arguments
# or missing required option.
# prints usage information

exit_failure_syntax()
{
    if [ $# -gt 0 ]; then
        echo "xdg-su: $@" >&2
        echo "Try 'xdg-su --help' for more information." >&2
    else
        usage
        echo "Use 'man xdg-su' or 'xdg-su --manual' for additional info."
    fi

    exit 1
}

#-------------------------------------------------------------
# Exit script on missing file specified on command line

exit_failure_file_missing()
{
    if [ $# -gt 0 ]; then
        echo "xdg-su: $@" >&2
    fi

    exit 2
}

#-------------------------------------------------------------
# Exit script on failure to locate necessary tool applications

exit_failure_operation_impossible()
{
    if [ $# -gt 0 ]; then
        echo "xdg-su: $@" >&2
    fi

    exit 3
}

#-------------------------------------------------------------
# Exit script on failure returned by a tool application

exit_failure_operation_failed()
{
    if [ $# -gt 0 ]; then
        echo "xdg-su: $@" >&2
    fi

    exit 4
}

#------------------------------------------------------------
# Exit script on insufficient permission to read a specified file

exit_failure_file_permission_read()
{
    if [ $# -gt 0 ]; then
        echo "xdg-su: $@" >&2
    fi

    exit 5
}

#------------------------------------------------------------
# Exit script on insufficient permission to read a specified file

exit_failure_file_permission_write()
{
    if [ $# -gt 0 ]; then
        echo "xdg-su: $@" >&2
    fi

    exit 6
}

check_input_file()
{
    if [ ! -e "$1" ]; then
        exit_failure_file_missing "file '$1' does not exist"
    fi
    if [ ! -r "$1" ]; then
        exit_failure_file_permission_read "no permission to read file '$1'"
    fi
}

check_vendor_prefix()
{
    file=`basename "$1"`
    case "$file" in
       [a-zA-Z]*-*)
         return
         ;;
    esac

    echo "xdg-su: filename '$file' does not have a proper vendor prefix" >&2
    echo 'A vendor prefix consists of alpha characters ([a-zA-Z]) and is terminated' >&2
    echo 'with a dash ("-"). An example filename is '"'example-$file'" >&2
    echo "Use --novendor to override or 'xdg-su --manual' for additional info." >&2
    exit 1
}

check_output_file()
{
    # if the file exists, check if it is writeable
    # if it does not exists, check if we are allowed to write on the directory
    if [ -e "$1" ]; then
        if [ ! -w "$1" ]; then
            exit_failure_file_permission_write "no permission to write to file '$1'"
        fi
    else
        DIR=`dirname "$1"`
        if [ ! -w "$DIR" -o ! -x "$DIR" ]; then
            exit_failure_file_permission_write "no permission to create file '$1'"
        fi
    fi
}

#----------------------------------------
# Checks for shared commands, e.g. --help

check_common_commands()
{
    while [ $# -gt 0 ] ; do
        parm="$1"
        shift

        case "$parm" in
            --help)
            usage
            echo "Use 'man xdg-su' or 'xdg-su --manual' for additional info."
            exit_success
            ;;

            --manual)
            manualpage
            exit_success
            ;;

            --version)
            echo "xdg-su 1.0beta2"
            exit_success
            ;;
        esac
    done
}

check_common_commands "$@"
if [ ${XDG_UTILS_DEBUG_LEVEL-0} -lt 1 ]; then
    # Be silent
    xdg_redirect_output=" > /dev/null 2> /dev/null"
else
    # All output to stderr
    xdg_redirect_output=" >&2"
fi

#--------------------------------------
# Checks for known desktop environments
# set variable DE to the desktop environments name, lowercase

detectDE()
{
    if [ x"$KDE_FULL_SESSION" = x"true" ]; then DE=kde;
    elif [ x"$GNOME_DESKTOP_SESSION_ID" != x"" ]; then DE=gnome;
    elif xprop -root _DT_SAVE_MODE | grep ' = \"xfce4\"$' >/dev/null 2>&1; then DE=xfce;
    fi
}

#----------------------------------------------------------------------------



su_kde()
{
    if [ x"$KDE_SESSION_VERSION" = x"4" ]; then
        KDESU=`kde4-config --locate kdesu --path exe 2>/dev/null`
    else
        KDESU=`which kdesu 2>/dev/null`
    fi
    if [ $? -eq 0 ] ; then
        if [ -z "$user" ] ; then
             $KDESU -c "$cmd"
        else
             $KDESU -u "$user" -c "$cmd"
        fi

        if [ $? -eq 0 ]; then
            exit_success
        else
            exit_failure_operation_failed
        fi
    else
        su_generic
    fi
}

su_gnome()
{
    GSU=`which gnomesu 2>/dev/null`
    if [ $? -ne 0 ] ; then
        GSU=`which xsu 2>/dev/null`
    fi
    if [ $? -eq 0 ] ; then
        if [ -z "$user" ] ; then
            $GSU -c "$cmd"
        else
            $GSU -u "$user" -c "$cmd"
        fi

        if [ $? -eq 0 ]; then
            exit_success
        else
            exit_failure_operation_failed
        fi
    else
        su_generic
    fi
}

su_generic()
{
    if [ -z "$user" ] ; then
        xterm -geom 60x5 -T "xdg-su: $cmd" -e su -c "$cmd"
    else
        xterm -geom 60x5 -T "xdg-su: $cmd" -e su -c "$cmd" "$user"
    fi

    if [ $? -eq 0 ]; then
        exit_success
    else
        exit_failure_operation_failed
    fi
}

[ x"$1" != x"" ] || exit_failure_syntax

user=
cmd=
while [ $# -gt 0 ] ; do
    parm="$1"
    shift

    case "$parm" in
      -u)
        if [ -z "$1" ] ; then
            exit_failure_syntax "user argument missing for -u"
        fi
        user="$1"
        shift
        ;;

      -c)
        if [ -z "$1" ] ; then
            exit_failure_syntax "command argument missing for -c"
        fi
        cmd="$1"
        shift
        ;;

      -*)
        exit_failure_syntax "unexpected option '$parm'"
        ;;

      *)
        exit_failure_syntax "unexpected argument '$parm'"
        ;;
    esac
done

if [ -z "${cmd}" ] ; then
    exit_failure_syntax "command missing"
fi

detectDE

if [ x"$DE" = x"" ]; then
    XSU=`which xsu 2>/dev/null`
    if [ $? -eq 0 ] ; then
        DE=generic
    fi
fi

case "$DE" in
    kde)
    su_kde
    ;;

    gnome)
    su_gnome
    ;;

    generic)
    su_generic
    ;;

    *)
    [ x"$user" = x"" ] && user=root 
    exit_failure_operation_impossible "no graphical method available for invoking '$cmd' as '$user'"
    ;;
esac
