users: Flush nscd cache after user operations

nscd monitors files in /etc and invalidates the cache automatically when
they change.  However, for other mechanisms it recommends issuing a
manual flush in its manual page.  Flush nscd passwd and group database
caches after all user operations (not just rename operation, just to be
sure).

CHANGELOG.md

@@ -11,6 +11,7 @@ All notable changes to this project will be documented in this file.
 - help: Minor updates and fixes to status log.
 - Updated translations to fix weblate errors.
 - Fixed spelling errors in datetime and letsencrypt modules.
+- users: Flush nscd cache after user operations.
 
 ### Changed
 - dynamicdns, transmission, upgrades: Allowed Plinth to run as non-root.

actions/ldap

@@ -34,6 +34,8 @@ create_user()
     ldapadduser $username users > /dev/null
 
     set_user_password $username $password
+
+    flush_cache
 }
 
 
@@ -48,6 +50,8 @@ delete_user()
     while read -r group; do
         ldapdeleteuserfromgroup $username $group > /dev/null || true
     done <<< "$groups"
+
+    flush_cache
 }
 
 
@@ -64,6 +68,8 @@ rename_user()
         ldapdeleteuserfromgroup $old_username $group > /dev/null || true
         ldapaddusertogroup $new_username $group > /dev/null || true
     done <<< "$groups"
+
+    flush_cache
 }
 
 
@@ -95,6 +101,8 @@ add_user_to_group()
     ldapaddgroup $groupname > /dev/null 2>&1 || true
 
     ldapaddusertogroup $username $groupname > /dev/null
+
+    flush_cache
 }
 
 
@@ -104,6 +112,16 @@ remove_user_from_group()
     groupname="$2"
 
     ldapdeleteuserfromgroup $username $groupname > /dev/null
+
+    flush_cache
+}
+
+
+flush_cache()
+{
+    # Flush nscd cache
+    nscd --invalidate=passwd
+    nscd --invalidate=group
 }