source: vendor/current/docs-xml/manpages/idmap_script.8.xml

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<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
<refentry id="idmap_script.8">

<refmeta>
        <refentrytitle>idmap_script</refentrytitle>
        <manvolnum>8</manvolnum>
        <refmiscinfo class="source">Samba</refmiscinfo>
        <refmiscinfo class="manual">System Administration tools</refmiscinfo>
        <refmiscinfo class="version">4.4</refmiscinfo>
</refmeta>


<refnamediv>
        <refname>idmap_script</refname>
        <refpurpose>Samba's idmap_script Backend for Winbind</refpurpose>
</refnamediv>

<refsynopsisdiv>
        <title>DESCRIPTION</title>

        <para>
        The idmap_script plugin is a substitute for the idmap_tdb2
        backend used by winbindd for storing SID/uid/gid mapping tables
        in clustered environments with Samba and CTDB. It is a read only
        backend that uses a script to perform mapping.
        </para>

        <para>
        It was developed out of the idmap_tdb2 back end and does not store
        SID/uid/gid mappings in a TDB, since the winbind_cache tdb will
        store the mappings once they are provided.
        </para>
</refsynopsisdiv>

<refsect1>
        <title>IDMAP OPTIONS</title>

        <variablelist>
                <varlistentry>
                <term>range = low - high</term>
                <listitem><para>
                        Defines the available matching uid and gid range for which the
                        backend is authoritative.
                </para></listitem>
                </varlistentry>

                <varlistentry>
                <term>script</term>
                <listitem><para>
                        This option can be used to configure an external program
                        for performing id mappings.
                </para></listitem>
                </varlistentry>
        </variablelist>
</refsect1>

<refsect1>
        <title>IDMAP SCRIPT</title>

        <para>
        The tdb2 idmap backend supports an external program for performing id mappings
        through the smb.conf option <parameter>idmap config * : script</parameter> or
        its deprecated legacy form <parameter>idmap : script</parameter>.
        </para>

        <para>
        The mappings obtained by the script are then stored in the idmap tdb2
        database instead of mappings created by the incrementing id counters.
        It is therefore important that the script covers the complete range of
        SIDs that can be passed in for SID to Unix ID mapping, since otherwise
        SIDs unmapped by the script might get mapped to IDs that had
        previously been mapped by the script.
        </para>

        <para>
        The script should accept the following command line options.
        </para>

        <programlisting>
        SIDTOID S-1-xxxx
        IDTOSID UID xxxx
        IDTOSID GID xxxx
        IDTOSID XID xxxx
        </programlisting>

        <para>
        And it should return one of the following responses as a single line of
        text.
        </para>

        <programlisting>
        UID:yyyy
        GID:yyyy
        XID:yyyy
        SID:ssss
        ERR:yyyy
        </programlisting>

        <para>
        XID indicates that the ID returned should be both a UID and a GID.
        That is, it requests an ID_TYPE_BOTH, but it is ultimately up to
        the script whether or not it can honor that request. It can choose
        to return a UID or a GID mapping only.
        </para>
</refsect1>

<refsect1>
        <title>EXAMPLES</title>

        <para>
        This example shows how script is used as a the default idmap backend
        using an external program via the script parameter:
        </para>

        <programlisting>
        [global]
        idmap config * : backend = script
        idmap config * : range = 1000000-2000000
        idmap config * : script = /usr/local/samba/bin/idmap_script.sh
        </programlisting>

        <para>
        This shows a simple script to partially perform the task:
        </para>

        <programlisting>
        #!/bin/sh
        #
        # Uncomment this if you want some logging
        #echo $@ >> /tmp/idmap.sh.log
        if [ "$1" == "SIDTOID" ]
        then
                # Note. The number returned has to be within the range defined
                #echo "Sending UID:1000005" >> /tmp/idmap.sh.log
                echo "UID:1000005"
                exit 0
        else
                #echo "Sending ERR: No idea what to do" >> /tmp/idmap.sh.log
                echo "ERR: No idea what to do"
                exit 1
        fi
        </programlisting>

        <para>
        Clearly, this script is not enough, as it should probably use wbinfo
        to determine if an incoming SID is a user or group SID and then
        look up the mapping in a table or use some other mechanism for
        mapping SIDs to UIDs and etc.
        </para>
</refsect1>

<refsect1>
        <title>AUTHOR</title>

        <para>
        The original Samba software and related utilities
        were created by Andrew Tridgell. Samba is now developed
        by the Samba Team as an Open Source project similar
        to the way the Linux kernel is developed.
        </para>
</refsect1>

</refentry>