source: branches/samba-3.5.x/examples/scripts/idmap/idmap_nis.sh

#!/bin/bash
# idmap script to map SIDs to UIDs/GIDs using NIS
# tridge@samba.org June 2009

DOMAIN=$(ypdomainname)

(
    date
    echo $*
) >> /var/log/samba/idmap.log

cmd=$1
shift

PATH=/usr/bin:bin:$PATH

shopt -s nocasematch || {
    echo "shell option nocasematch not supported"
    exit 1
}

# map from a domain and name to a uid/gid
map_name() {
    domain="$1"
    name="$2"
    ntype="$3"
    case $ntype in
        1)
            rtype="UID"
            map="passwd"
            ;;
        2)
            rtype="GID"
            map="group"
            ;;
        *)
            echo "ERR: bad name type $ntype"
            exit 1
            ;;
    esac
    id=$(ypmatch "$name" "$map".byname 2>/dev/null | cut -d: -f3)
    [ -z "$id" ] && {
        echo "ERR: bad match for $name in map $map"
        exit 1
    }
    echo "$rtype":"$id"
}

# map from a unix id to a name
map_id() {
    ntype="$1"
    id="$2"
    case $ntype in
        UID)
            map="passwd.byuid"
            ;;
        GID)
            map="group.bygid"
            ;;
        *)
            echo "ERR: bad name type $ntype"
            exit 1
            ;;
    esac
    name="$(ypmatch "$id" "$map" 2>/dev/null | cut -d: -f1)"
    [ -z "$name" ] && {
        echo "ERR: bad match for $name in map $map"
        exit 1
    }
    echo "$name"
}


case $cmd in
    SIDTOID)
        sid=$1
        rid=`echo $sid | cut -d- -f8`
        [ -z "$rid" ] && {
            echo "ERR: bad rid in SID $sid"
            exit 1
        }
        
        unset _NO_WINBINDD
        # oh, this is ugly. Shell is just not meant for parsing text
        fullname=`wbinfo -s $sid 2> /dev/null`
        domain=`echo $fullname | cut -d'\' -f1`
        [[ "$domain" = $DOMAIN ]] || {
            echo "ERR: bad domain $domain"
            exit 1
        }
        name=`echo $fullname | cut -d'\' -f2`
        nwords=`echo $name | wc -w`
        ntype=`echo $name | cut -d' ' -f$nwords`
        nminusone=`expr $nwords - 1`
        name=`echo $name | cut -d' ' -f-$nminusone`
        [ -z "$name" ] && {
            echo "ERR: bad name $fullname for SID $sid"
            exit 1
        }
        map_name "$domain" "$name" "$ntype"
        ;;
    IDTOSID)
        ntype=$1
        id=$2
        name="$(map_id "$ntype" "$id")"
        sid="$(wbinfo -n "$name" 2>/dev/null | cut -d' ' -f1)"
        [ -z "$sid" ] && {
            echo "ERR: name $name not found in ADS"
            exit 1
        }
        echo "SID:$sid"
        ;;
    *)
        echo "ERR: Unknown command $cmd"
        exit 1;
        ;;
esac

exit 0