##
##  OSSP due - Dynamic User Environment
##  Copyright (c) 1994-2004 Ralf S. Engelschall <rse@engelschall.com>
##  Copyright (c) 1994-2004 The OSSP Project <http://www.ossp.org/>
##
##  This file is part of OSSP due, a dynamic user environment
##  which can found at http://www.ossp.org/pkg/tool/due/
##
##  Permission to use, copy, modify, and distribute this software for
##  any purpose with or without fee is hereby granted, provided that
##  the above copyright notice and this permission notice appear in all
##  copies.
##
##  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
##  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
##  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
##  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
##  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
##  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
##  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
##  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
##  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
##  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
##  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
##  SUCH DAMAGE.
##
##  due.root.sh: DUE module for root command execution
##

#   generate shell script for re-evaluation of command arguments
#   input:  foo 'bar  baz' quux       (3 args)
#   output: "foo \"bar  baz\" quux"   (1 arg)
function _arg2sh () {
    local opt_e=no
    local opt_t=no
    local opt
    OPTIND=1
    while getopts et opt; do
        case ${opt} in
            e ) opt_e=yes ;;
            t ) opt_t=yes ;;
        esac
    done
    shift $(($OPTIND - 1))
    local cmd=""
    local arg
    for arg in "$@"; do
        #   NOTICE: there are three(!) escaping layers here:
        #   - escape layer 1: backticks (`..xx..`)
        #   - escape layer 2: quotes    ('..xx..')
        #   - escape layer 3: sed regex (s;..xx..;..xx..;)
        local orig=$arg
        if [ ${opt_e} = yes ]; then
            arg=`echo "@${arg}" | sed -e 's;^@;;' -e 's;\\\\;\\\\\\\\;g' -e 's;\\(["]\\);\\\\\\1;g'`
        elif [ ${opt_t} = yes ]; then
            arg=`echo "@${arg}" | sed -e 's;^@;;' -e 's;\\\\;\\\\\\\\;g' -e 's;\\(["!\$\`]\\);\\\\\\1;g'`
        fi
        local quote=no
        if [ "${arg}" != "${orig}" ]; then
            quote=yes
        else
            quote=`echo "@${arg}" | sed -e 's;^@.*[ 	].*\$;yes;' -e 's;^@.*;no;'`
        fi
        if [ ${quote} = yes ]; then
            arg=`echo "@${arg}" |\
                 sed -e 's;^@\([A-Z][A-Z0-9_]*\)=\(.*\)$;\1="\2";' \
                     -e 's;^@\(.*\)$;"\1";'`
        fi
        cmd="${cmd}${cmd:+ }${arg}"
    done
    printf "%s" "${cmd}" # intentionally not echo(1)
}

#   generate shell script for re-evaluation of environment variables
#   input:  PATH HOME                     (2 args)
#   output: "PATH=\"...\"; HOME=\"...\""  (1 arg)
function _env2sh () {
    local cmd=""
    local arg
    for arg in "$@"; do
        local val
        eval "val=\"\$${arg}\""
        #   NOTICE: there are three(!) escaping layers here, too.
        val=`echo "@${val}" | sed -e 's;^@;;' -e 's;\\\\;\\\\\\\\;g' -e 's;\\(["!\$\`]\\);\\\\\\1;g'`
        cmd="${cmd}${cmd:+; }${arg}=\"${val}\""
    done
    printf "%s" "${cmd}" # intentionally not echo(1)
}

#   smart dealing with temporary root privileges
function root () {
    #   default operation
    if [ $# -eq 0 ]; then
        set -- -i
    fi
       
    #   parse command line options
    local opt_i=no # interactive shell
    local opt_l=no # last command-line
    local opt_e=no # remote expansion mode
    local opt
    OPTIND=1
    while getopts ileh opt; do
        case ${opt} in
            i ) opt_i=yes ;;
            l ) opt_l=yes ;;
            e ) opt_e=yes ;;
            h ) echo "root:Usage: root [-h] [-l] [-e] command"; return 0 ;;
            ? ) echo "root:Error: invalid command line";        return 1 ;;
        esac
    done
    shift $(($OPTIND - 1))

    #   determine action(s)
    local prolog=":"
    local epilog=":"
    local command
    if [ ${opt_i} = yes ]; then
        #   enter interactive session with root privileges
        local xtermcontrol=`find_tool xtermcontrol xtermcolors`
        if [ -n "${xtermcontrol}" ]; then
            prolog="${xtermcontrol} --cursor='#cc3333'"
            epilog="${xtermcontrol} --cursor='#000000'"
            command="PS1=\"\\[\\e[31;1m\\]\\u\\[\\e[0m\\]@\\h:\\w\\n\\\\\\$ \"; export PS1"
        fi
        command="${command}${command:+; }exec ${SHELL} --norc --noprofile"
    elif [ ${opt_l} = yes -a ${opt_e} = yes ]; then
        eval "set -- $(builtin history 2 | sed -n -e '1p' | cut -c8-)"
        command=$(_arg2sh -e -- "$@")
    elif [ ${opt_l} = yes ]; then
        #   execute last command-line with root privileges
        command=$(builtin history 2 | sed -n -e '1p' | cut -c8-)
    elif [ ${opt_e} = yes ]; then
        #   execute given command-line with root privileges (expansion mode)
        command=$(_arg2sh -e -- "$@")
    else
        #   execute given command-line with root privileges (transparent mode)
        command=$(_arg2sh -t -- "$@")
    fi

    #   generate action command
    local cmd=$(_env2sh ${ROOT_ENV:-PATH MANPATH INFOPATH LD_LIBRARY_PATH TERM HOME EDITOR PAGER LOGNAME USER})
    cmd="${cmd}; cd ${PWD} && ${command}"
    cmd=$(_arg2sh -t -- "${cmd}")
    eval ${prolog}; ssh -t -q -x root@${HOSTNAME} ${SHELL} -c "${cmd}"; rv=$?; eval ${epilog}

    #   exit with return value of remote command 
    return $rv
}