docs: extend the idmap_rid manpage

Michael

diff --git a/docs-xml/manpages-3/idmap_rid.8.xml b/docs-xml/manpages-3/idmap_rid.8.xml
index 5eba356a7df999eae3d4fc2011e828988b31c906..7e48c11c53189cfa0a29007a213344de0fa617dd 100644 (file)
--- a/docs-xml/manpages-3/idmap_rid.8.xml
+++ b/docs-xml/manpages-3/idmap_rid.8.xml
@@ -42,11 +42,13 @@
                <varlistentry>
                <term>base_rid = INTEGER</term>
                <listitem><para>
-                       Defines the base integer used to build SIDs out of an UID or a GID,
-                       and to rebase the UID or GID to be obtained from a SID. User RIDs
-                       by default start at 1000 (512 hexadecimal), this means a good value
-                       for base_rid can be 1000 as the resulting ID is calculated this way:
-                       ID = RID - BASE_RID + LOW RANGE ID.
+                       Defines the base integer used to build SIDs out of a UID or a GID,
+                       and to rebase the UID or GID to be obtained from a SID.
+                       This means SIDs with a RID less than the base rid are filtered.
+                       The default is not to restrict the allowed rids at all,
+                       i.e. a base_rid value of 0.
+                       A good value for the base_rid can be 1000, since user
+                       RIDs by default start at 1000 (512 hexadecimal).
                </para>
                <para>
                        Use of this parameter is deprecated.
@@ -55,6 +57,23 @@
        </variablelist>
 </refsect1>
 
+<refsect1>
+       <title>THE MAPPING FORMULAS</title>
+       <para>
+               The Unix ID for a RID is calculated this way:
+               <programlisting>
+                       ID = RID - BASE_RID + LOW_RANGE_ID.
+               </programlisting>
+       </para>
+       <para>
+               Correspondingly, the formula for calculationg the RID for a
+               given Unix ID is this:
+               <programlisting>
+                       RID = ID + BASE_RID - LOW_RANGE_ID.
+               </programlisting>
+       </para>
+</refsect1>
+
 <refsect1>
        <title>EXAMPLES</title>
        <para>This example shows how to configure a domain with idmap_rid</para>