libnm/vpn: add nm_vpn_editor_plugin_load_vt()th/vpn-service-info-bgo767197

Let VPN plugins return a virtual function table to extend
the API while bypassing libnm. This allows to add and use
new functionality to VPN plugins without updating libnm.

The actual definitions are in a header-only file
"nm-vpn-editor-plugin-call.h", which can be copied to the
caller/plugin.

7 files changed, 255 insertions, 1 deletions

diff --git a/libnm-core/nm-vpn-editor-plugin.c b/libnm-core/nm-vpn-editor-plugin.c
index 1a4944b066..bc72ca3911 100644
--- a/libnm-core/nm-vpn-editor-plugin.c
+++ b/libnm-core/nm-vpn-editor-plugin.c
@@ -180,6 +180,53 @@ nm_vpn_editor_plugin_set_plugin_info (NMVpnEditorPlugin *plugin, NMVpnPluginInfo
 
 /*********************************************************************/
 
+/**
+ * nm_vpn_editor_plugin_get_vt:
+ * @plugin: the #NMVpnEditorPlugin
+ * @vt: (out): buffer to be filled with the VT table of the plugin
+ * @vt_size: the size of the buffer. Can be 0 to only query the
+ *   size of plugin's VT.
+ *
+ * Returns an opaque VT function table for the plugin to extend
+ * functionality. The actual meaning of NMVpnEditorPluginVT is not
+ * defined in public API of libnm, instead it must be agreed by
+ * both the plugin and the caller. See the header-only file
+ * 'nm-vpn-editor-plugin-call.h' which defines the meaning.
+ *
+ * Returns: the actual size of the @plugin's virtual function table.
+ *
+ * Since: 1.4
+ **/
+gsize
+nm_vpn_editor_plugin_get_vt (NMVpnEditorPlugin *plugin,
+                             NMVpnEditorPluginVT *vt,
+                             gsize vt_size)
+{
+	const NMVpnEditorPluginVT *p_vt = NULL;
+	gsize p_vt_size = 0;
+	NMVpnEditorPluginInterface *interface;
+
+	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), 0);
+
+	if (vt_size) {
+		g_return_val_if_fail (vt, 0);
+		memset (vt, 0, vt_size);
+	}
+
+	interface = NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin);
+	if (interface->get_vt) {
+		p_vt = interface->get_vt (plugin, &p_vt_size);
+		if (!p_vt)
+			p_vt_size = 0;
+		g_return_val_if_fail (p_vt_size, 0);
+		memcpy (vt, p_vt, MIN (vt_size, p_vt_size));
+	}
+
+	return p_vt_size;
+}
+
+/*********************************************************************/
+
 static NMVpnEditorPlugin *
 _nm_vpn_editor_plugin_load (const char *plugin_name,
                             gboolean do_file_checks,
diff --git a/libnm-core/nm-vpn-editor-plugin.h b/libnm-core/nm-vpn-editor-plugin.h
index dc18f04b74..fb51f7e621 100644
--- a/libnm-core/nm-vpn-editor-plugin.h
+++ b/libnm-core/nm-vpn-editor-plugin.h
@@ -82,6 +82,8 @@ typedef enum /*< flags >*/ {
 /* D-Bus service name of the plugin's VPN service */
 #define NM_VPN_EDITOR_PLUGIN_SERVICE "service"
 
+typedef struct _NMVpnEditorPluginVT NMVpnEditorPluginVT;
+
 /**
  * NMVpnEditorPluginInterface:
  * @g_iface: the parent interface
@@ -99,6 +101,8 @@ typedef enum /*< flags >*/ {
  * @get_suggested_filename: For a given connection, return a suggested file
  *   name.  Returned value will be %NULL or a suggested file name to be freed by
  *   the caller.
+ * @get_vt: return a virtual function table to implement further functions in
+ *   the plugin, without requiring to update libnm. Used by nm_vpn_editor_plugin_get_vt().
  *
  * Interface for VPN editor plugins.
  */
@@ -124,6 +128,9 @@ typedef struct {
 
 	void (*notify_plugin_info_set) (NMVpnEditorPlugin *plugin,
 	                                struct _NMVpnPluginInfo *plugin_info);
+
+	const NMVpnEditorPluginVT *(*get_vt) (NMVpnEditorPlugin *plugin,
+	                                      gsize *out_vt_size);
 } NMVpnEditorPluginInterface;
 
 GType nm_vpn_editor_plugin_get_type (void);
@@ -134,6 +141,11 @@ NMVpnEditor *nm_vpn_editor_plugin_get_editor (NMVpnEditorPlugin *plugin,
 
 NMVpnEditorPluginCapability nm_vpn_editor_plugin_get_capabilities (NMVpnEditorPlugin *plugin);
 
+NM_AVAILABLE_IN_1_4
+gsize nm_vpn_editor_plugin_get_vt (NMVpnEditorPlugin *plugin,
+                                   NMVpnEditorPluginVT *vt,
+                                   gsize vt_size);
+
 NMConnection *nm_vpn_editor_plugin_import                 (NMVpnEditorPlugin *plugin,
                                                            const char *path,
                                                            GError **error);
diff --git a/libnm/libnm.ver b/libnm/libnm.ver
index 2dc2103517..41f650f008 100644
--- a/libnm/libnm.ver
+++ b/libnm/libnm.ver
@@ -1069,6 +1069,7 @@ global:
 	nm_setting_ip6_config_get_token;
 	nm_setting_ip_config_get_dns_priority;
 	nm_vpn_editor_plugin_get_plugin_info;
+	nm_vpn_editor_plugin_get_vt;
 	nm_vpn_editor_plugin_load;
 	nm_vpn_editor_plugin_set_plugin_info;
 	nm_vpn_plugin_info_get_aliases;
diff --git a/libnm/nm-vpn-service-plugin.c b/libnm/nm-vpn-service-plugin.c
index bf4369e4ad..df99eb28d9 100644
--- a/libnm/nm-vpn-service-plugin.c
+++ b/libnm/nm-vpn-service-plugin.c
@@ -1306,3 +1306,11 @@ nm_vpn_service_plugin_initable_iface_init (GInitableIface *iface)
 {
 	iface->init = init_sync;
 }
+
+/*****************************************************************************/
+
+/* this header is intended to be copied to users of nm_vpn_editor_plugin_call(),
+ * to simplify invocation of generic functions. Include it here, to complile
+ * the code. */
+#include "nm-vpn-editor-plugin-call.h"
+
diff --git a/po/POTFILES.skip b/po/POTFILES.skip
index 70e222c6a9..2e36b03a17 100644
--- a/po/POTFILES.skip
+++ b/po/POTFILES.skip
@@ -7,4 +7,5 @@ vpn-daemons/pptp
 vpn-daemons/vpnc
 contrib/fedora/rpm/
 # https://bugs.launchpad.net/intltool/+bug/1117944
+shared/nm-vpn-editor-plugin-call.h
 sub/policy/org.freedesktop.NetworkManager.policy.in
diff --git a/shared/Makefile.am b/shared/Makefile.am
index c6ede00b6a..01818d0cd1 100644
--- a/shared/Makefile.am
+++ b/shared/Makefile.am
@@ -10,6 +10,7 @@ EXTRA_DIST = \
      nm-test-libnm-utils.h \
      nm-test-utils.h \
      nm-test-utils-impl.c \
-     nm-version-macros.h.in
+     nm-version-macros.h.in \
+     nm-vpn-editor-plugin-call.h
 
 CLEANFILES=nm-version.h
diff --git a/shared/nm-vpn-editor-plugin-call.h b/shared/nm-vpn-editor-plugin-call.h
new file mode 100644
index 0000000000..584f3787d5
--- /dev/null
+++ b/shared/nm-vpn-editor-plugin-call.h
@@ -0,0 +1,184 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
+/* NetworkManager -- Network link manager
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright (C) 2016 Red Hat, Inc.
+ */
+
+#ifndef __NM_VPN_EDITOR_PLUGIN_CALL_H__
+#define __NM_VPN_EDITOR_PLUGIN_CALL_H__
+
+/* This header is an internal, header-only file that can be copied to
+ * other projects to call well-known service functions on VPN plugins. */
+
+#include <NetworkManager.h>
+
+/* we make use of otherinternal header files, you need those too. */
+#include "gsystem-local-alloc.h"
+#include "nm-macros-internal.h"
+
+/*****************************************************************************/
+
+/**
+ * NMVpnEditorPluginServiceFlags:
+ * @NM_VPN_EDITOR_PLUGIN_SERVICE_FLAGS_NONE: no flags
+ * @NM_VPN_EDITOR_PLUGIN_SERVICE_FLAGS_CAN_ADD: whether the plugin can
+ *   add a new connection for the given service-type.
+ **/
+typedef enum { /*< skip >*/
+	NM_VPN_EDITOR_PLUGIN_SERVICE_FLAGS_NONE     = 0x00,
+	NM_VPN_EDITOR_PLUGIN_SERVICE_FLAGS_CAN_ADD  = 0x01,
+} NMVpnEditorPluginServiceFlags;
+
+struct _NMVpnEditorPluginVT {
+	gboolean (*fcn_get_service_info) (NMVpnEditorPlugin *plugin,
+	                                  const char *service_type,
+	                                  char **out_short_name,
+	                                  char **out_pretty_name,
+	                                  char **out_description,
+	                                  NMVpnEditorPluginServiceFlags *out_flags);
+	char **(*fcn_get_service_add_details) (NMVpnEditorPlugin *plugin,
+	                                       const char *service_name);
+	gboolean (*fcn_get_service_add_detail) (NMVpnEditorPlugin *plugin,
+	                                        const char *service_type,
+	                                        const char *add_detail,
+	                                        char **out_pretty_name,
+	                                        char **out_description,
+	                                        char **out_add_detail_key,
+	                                        char **out_add_detail_val,
+	                                        guint *out_flags);
+};
+
+/*****************************************************************************
+ * Call
+ *
+ * The following wrap the calling of generic functions for a VPN plugin.
+ * They are used by callers (for example nm-connection-editor).
+ *****************************************************************************/
+
+static inline gboolean
+nm_vpn_editor_plugin_get_service_info (NMVpnEditorPlugin *plugin,
+                                       const char *service_type,
+                                       char **out_short_name,
+                                       char **out_pretty_name,
+                                       char **out_description,
+                                       NMVpnEditorPluginServiceFlags *out_flags)
+{
+	NMVpnEditorPluginVT vt;
+	gs_free char *short_name_local = NULL;
+	gs_free char *pretty_name_local = NULL;
+	gs_free char *description_local = NULL;
+	guint flags_local = 0;
+
+	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), FALSE);
+	g_return_val_if_fail (service_type, FALSE);
+
+	nm_vpn_editor_plugin_get_vt (plugin, &vt, sizeof (vt));
+	if (   !vt.fcn_get_service_info
+	    || !vt.fcn_get_service_info (plugin,
+	                                 service_type,
+	                                 out_short_name  ? &short_name_local : NULL,
+	                                 out_pretty_name ? &pretty_name_local : NULL,
+	                                 out_description ? &description_local : NULL,
+	                                 out_flags       ? &flags_local : NULL))
+		return FALSE;
+	NM_SET_OUT (out_short_name, g_steal_pointer (&short_name_local));
+	NM_SET_OUT (out_pretty_name, g_steal_pointer (&pretty_name_local));
+	NM_SET_OUT (out_description, g_steal_pointer (&description_local));
+	NM_SET_OUT (out_flags, flags_local);
+	return TRUE;
+}
+
+static inline char **
+nm_vpn_editor_plugin_get_service_add_details (NMVpnEditorPlugin *plugin,
+                                              const char *service_name)
+{
+	NMVpnEditorPluginVT vt;
+	char **details = NULL;
+
+	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), NULL);
+	g_return_val_if_fail (service_name, NULL);
+
+	nm_vpn_editor_plugin_get_vt (plugin, &vt, sizeof (vt));
+	if (vt.fcn_get_service_add_details)
+		details = vt.fcn_get_service_add_details (plugin, service_name);
+	if (!details)
+		return g_new0 (char *, 1);
+	return details;
+}
+
+static inline gboolean
+nm_vpn_editor_plugin_get_service_add_detail (NMVpnEditorPlugin *plugin,
+                                             const char *service_type,
+                                             const char *add_detail,
+                                             char **out_pretty_name,
+                                             char **out_description,
+                                             char **out_add_detail_key,
+                                             char **out_add_detail_val,
+                                             guint *out_flags)
+{
+	NMVpnEditorPluginVT vt;
+	gs_free char *pretty_name_local = NULL;
+	gs_free char *description_local = NULL;
+	gs_free char *add_detail_key_local = NULL;
+	gs_free char *add_detail_val_local = NULL;
+	guint flags_local = 0;
+
+	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), FALSE);
+	g_return_val_if_fail (service_type, FALSE);
+	g_return_val_if_fail (add_detail, FALSE);
+
+	nm_vpn_editor_plugin_get_vt (plugin, &vt, sizeof (vt));
+	if (   !vt.fcn_get_service_add_detail
+	    || !vt.fcn_get_service_add_detail (plugin,
+	                                       service_type,
+	                                       add_detail,
+	                                       out_pretty_name    ? &pretty_name_local : NULL,
+	                                       out_description    ? &description_local : NULL,
+	                                       out_add_detail_key ? &add_detail_key_local : NULL,
+	                                       out_add_detail_val ? &add_detail_val_local : NULL,
+	                                       out_flags          ? &flags_local : NULL))
+		return FALSE;
+	NM_SET_OUT (out_pretty_name, g_steal_pointer (&pretty_name_local));
+	NM_SET_OUT (out_description, g_steal_pointer (&description_local));
+	NM_SET_OUT (out_add_detail_key, g_steal_pointer (&add_detail_key_local));
+	NM_SET_OUT (out_add_detail_val, g_steal_pointer (&add_detail_val_local));
+	NM_SET_OUT (out_flags, flags_local);
+	return TRUE;
+}
+
+/*****************************************************************************
+ * Implementation
+ *
+ * The following glue code can be used to implement calls in a VPN plugin.
+ *****************************************************************************/
+
+#define NM_VPN_EDITOR_PLUGIN_VT_DEFINE(vt_name, get_vt, ...) \
+static const NMVpnEditorPluginVT vt_name = { \
+		__VA_ARGS__ \
+	}; \
+static const NMVpnEditorPluginVT * \
+get_vt (NMVpnEditorPlugin *plugin, \
+        gsize *out_vt_size) \
+{ \
+	nm_assert (NM_IS_VPN_EDITOR_PLUGIN (plugin)); \
+	nm_assert (out_vt_size); \
+	\
+	*out_vt_size = sizeof (vt_name); \
+	return &vt_name; \
+}
+
+#endif /* __NM_VPN_EDITOR_PLUGIN_CALL_H__ */