ldapurl is supported with simple bind

The docs currently imply that ldapurl is for search+bind only, but
that's not true.  Rearrange the docs to cover this better.

Add a test ldapurl with simple bind.  This was previously allowed but
unexercised, and now that it's documented it'd be good to pin the
behavior.

Improve error when mixing LDAP bind modes.  The option names had gone
stale; replace them with a more general statement.

Author: Jacob Champion <jacob.champion@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/CAOYmi+nyg9gE0LeP=xQ3AgyQGR=5ZZMkVVbWd0uR8XQmg_dd5Q@mail.gmail.com

doc/src/sgml/client-auth.sgml

@@ -1910,13 +1910,19 @@ omicron         bryanh                  guest1
         </para>
        </listitem>
       </varlistentry>
+     </variablelist>
+    </para>
+
+    <para>
+     The following option may be used as an alternative way to write some of the
+     above LDAP options in a more compact and standard form:
+     <variablelist>
       <varlistentry>
        <term><literal>ldapurl</literal></term>
        <listitem>
         <para>
          An <ulink url="https://datatracker.ietf.org/doc/html/rfc4516">RFC 4516</ulink>
-         LDAP URL.  This is an alternative way to write some of the
+         LDAP URL.  The format is
-         other LDAP options in a more compact and standard form.  The format is
 <synopsis>
 ldap[s]://<replaceable>host</replaceable>[:<replaceable>port</replaceable>]/<replaceable>basedn</replaceable>[?[<replaceable>attribute</replaceable>][?[<replaceable>scope</replaceable>][?[<replaceable>filter</replaceable>]]]]
 </synopsis>
@@ -1958,7 +1964,8 @@ ldap[s]://<replaceable>host</replaceable>[:<replaceable>port</replaceable>]/<rep
 
    <para>
     It is an error to mix configuration options for simple bind with options
-    for search+bind.
+    for search+bind.  To use <literal>ldapurl</literal> in simple bind mode, the
+    URL must not contain a <literal>basedn</literal> or query elements.
    </para>
 
    <para>
@@ -1994,6 +2001,16 @@ host ... ldap ldapserver=ldap.example.net ldapprefix="cn=" ldapsuffix=", dc=exam
     succeeds, the database access is granted.
    </para>
 
+   <para>
+    Here is a different simple-bind configuration, which uses the LDAPS scheme
+    and a custom port number, written as a URL:
+<programlisting>
+host ... ldap ldapurl="ldaps://ldap.example.net:49151" ldapprefix="cn=" ldapsuffix=", dc=example, dc=net"
+</programlisting>
+    This is slightly more compact than specifying <literal>ldapserver</literal>,
+    <literal>ldapscheme</literal>, and <literal>ldapport</literal> separately.
+   </para>
+
    <para>
     Here is an example for a search+bind configuration:
 <programlisting>

src/backend/libpq/hba.c

@@ -1907,10 +1907,10 @@ parse_hba_line(TokenizedAuthLine *tok_line, int elevel)
 			{
 				ereport(elevel,
 						(errcode(ERRCODE_CONFIG_FILE_ERROR),
-						 errmsg("cannot use ldapbasedn, ldapbinddn, ldapbindpasswd, ldapsearchattribute, ldapsearchfilter, or ldapurl together with ldapprefix"),
+						 errmsg("cannot mix options for simple bind and search+bind modes"),
 						 errcontext("line %d of configuration file \"%s\"",
 									line_num, file_name)));
-				*err_msg = "cannot use ldapbasedn, ldapbinddn, ldapbindpasswd, ldapsearchattribute, ldapsearchfilter, or ldapurl together with ldapprefix";
+				*err_msg = "cannot mix options for simple bind and search+bind modes";
 				return NULL;
 			}
 		}

src/test/ldap/t/001_auth.pl

@@ -145,6 +145,22 @@ test_access($node, 'test1', 0, 'search+bind authentication succeeds');
 
 note "LDAP URLs";
 
+unlink($node->data_dir . '/pg_hba.conf');
+$node->append_conf('pg_hba.conf',
+	qq{local all all ldap ldapurl="$ldap_url" ldapprefix="uid=" ldapsuffix=",dc=example,dc=net"}
+);
+$node->restart;
+
+$ENV{"PGPASSWORD"} = 'wrong';
+test_access($node, 'test0', 2,
+	'simple bind with LDAP URL authentication fails if user not found in LDAP'
+);
+test_access($node, 'test1', 2,
+	'simple bind with LDAP URL authentication fails with wrong password');
+$ENV{"PGPASSWORD"} = 'secret1';
+test_access($node, 'test1', 0,
+	'simple bind with LDAP URL authentication succeeds');
+
 unlink($node->data_dir . '/pg_hba.conf');
 $node->append_conf('pg_hba.conf',
 	qq{local all all ldap ldapurl="$ldap_url/$ldap_basedn?uid?sub"});