plugins: follow the footsteps of plugins_syslog() and plugins_services()

This looks simple enough now.  Discussed with @adschellevis.

(cherry picked from commit 1d73b3b5)
(cherry picked from commit ab4f67c8)
(cherry picked from commit 47c3fee7)
(cherry picked from commit 3947fff4)

src/etc/inc/config.lib.inc

@@ -177,9 +177,15 @@ function write_config($desc = '', $backup = true)
         return -1;
     }
 
+    if (function_exists('plugins_interfaces')) {
+        /* only pull plugins if plugins.inc was included before */
+        plugins_interfaces(false);
+    }
+
     $cnf = OPNsense\Core\Config::getInstance();
     $cnf->fromArray($config);
     $revision_info = make_config_revision_entry($desc);
+
     try {
         $cnf->save($revision_info, $backup);
     } catch (OPNsense\Core\ConfigException $e) {

src/www/interfaces_groups.php

@@ -53,7 +53,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             }
         }
         unset($a_ifgroups[$id]);
-        plugins_interfaces(false);
         write_config();
         header("Location: interfaces_groups.php");
         exit;

src/www/interfaces_groups_edit.php

@@ -125,7 +125,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
           // add new item
           $a_ifgroups[] = $ifgroupentry;
       }
-      plugins_interfaces(false);
       write_config();
       interface_group_setup($ifgroupentry);
       header("Location: interfaces_groups.php");

src/www/vpn_ipsec.php

@@ -112,9 +112,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             unset($config['ipsec']['phase1'][$p1entrydel]);
         }
 
-        if (write_config()) {
+        write_config();
         mark_subsystem_dirty('ipsec');
-        }
         header("Location: vpn_ipsec.php");
         exit;
     } elseif (!empty($_POST['act']) && $_POST['act'] == "delphase2" ) {
@@ -125,9 +124,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                 unset($config['ipsec']['phase2'][$p1entrydel]);
             }
         }
-        if (write_config()) {
+        write_config();
         mark_subsystem_dirty('ipsec');
-        }
         header("Location: vpn_ipsec.php");
         exit;
     } elseif (!empty($_POST['act']) && $_POST['act'] == "movep1" ) {
@@ -141,9 +139,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             }
             $a_phase1 = legacy_move_config_list_items($a_phase1, $id,  $_POST['p1entry']);
         }
-        if (write_config()) {
+        write_config();
         mark_subsystem_dirty('ipsec');
-        }
         header("Location: vpn_ipsec.php");
         exit;
     } elseif (!empty($_POST['act']) && $_POST['act'] == "movep2" ) {
@@ -157,9 +154,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             }
             $a_phase2 = legacy_move_config_list_items($a_phase2, $id,  $_POST['p2entry']);
         }
-        if (write_config()) {
+        write_config();
         mark_subsystem_dirty('ipsec');
-        }
         header("Location: vpn_ipsec.php");
         exit;
     } elseif (!empty($_POST['act']) && $_POST['act'] == "togglep1" && isset($a_phase1[$_POST['id']]) ) {
@@ -169,9 +165,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         } else {
             $a_phase1[$_POST['id']]['disabled'] = true;
         }
-        if (write_config()) {
+        write_config();
         mark_subsystem_dirty('ipsec');
-        }
         header("Location: vpn_ipsec.php");
         exit;
     } elseif (!empty($_POST['act']) && $_POST['act'] == "togglep2" && isset($a_phase2[$_POST['id']]) ) {
@@ -181,9 +176,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         } else {
             $a_phase2[$_POST['id']]['disabled'] = true;
         }
-        if (write_config()) {
+        write_config();
         mark_subsystem_dirty('ipsec');
-        }
         header("Location: vpn_ipsec.php");
         exit;
     }

src/www/vpn_openvpn_client.php

@@ -31,6 +31,7 @@ require_once("guiconfig.inc");
 require_once("openvpn.inc");
 require_once("services.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 
 if (!isset($config['openvpn']['openvpn-client'])) {
     $config['openvpn']['openvpn-client'] = array();

src/www/vpn_openvpn_csc.php

@@ -31,6 +31,7 @@ require_once("guiconfig.inc");
 require_once("openvpn.inc");
 require_once("services.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 
 // define all fields used in this form
 $all_form_fields = "custom_options,disable,common_name,block,description

src/www/vpn_openvpn_export.php

@@ -32,6 +32,7 @@ require_once("openvpn.inc");
 require_once("services.inc");
 require_once("filter.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 require_once("openvpn-client-export.inc");
 
 global $current_openvpn_version, $current_openvpn_version_rev;

src/www/vpn_openvpn_server.php

@@ -31,6 +31,7 @@ require_once("guiconfig.inc");
 require_once("openvpn.inc");
 require_once("services.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 
 if (!isset($config['openvpn']['openvpn-server'])) {
     $config['openvpn']['openvpn-server'] = array();

src/www/wizard.php

@@ -33,6 +33,7 @@ require_once("filter.inc");
 require_once("rrd.inc");
 require_once("system.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 
 /*
  * find_ip_interface($ip): return the interface where an ip is defined