plugin-manager: dynamically load 'shared' util libraries

plugins/Makefile.am

@@ -37,6 +37,14 @@ AM_CFLAGS  += $(MBIM_CFLAGS)
 AM_LDFLAGS += $(MBIM_LIBS)
 endif
 
+# Common compiler/linker flags for shared utils
+SHARED_COMMON_COMPILER_FLAGS = \
+	$(NULL)
+SHARED_COMMON_LINKER_FLAGS = \
+	-module        \
+	-avoid-version \
+	$(NULL)
+
 # Common compiler/linker flags for plugins
 PLUGIN_COMMON_COMPILER_FLAGS = \
 	$(NULL)

src/Makefile.am

@@ -350,6 +350,7 @@ ModemManager_SOURCES = \
 	mm-port-probe-at.c \
 	mm-plugin.c \
 	mm-plugin.h \
+	mm-shared.h \
 	$(NULL)
 
 nodist_ModemManager_SOURCES = $(DAEMON_ENUMS_GENERATED)

src/mm-plugin-manager.c

@@ -12,8 +12,8 @@
  *
  * Copyright (C) 2008 - 2009 Novell, Inc.
  * Copyright (C) 2009 - 2012 Red Hat, Inc.
- * Copyright (C) 2011 - 2012 Aleksander Morgado <aleksander@gnu.org>
  * Copyright (C) 2012 Google, Inc.
+ * Copyright (C) 2011 - 2019 Aleksander Morgado <aleksander@gnu.org>
  */
 
 #include <string.h>
@@ -27,8 +27,12 @@
 
 #include "mm-plugin-manager.h"
 #include "mm-plugin.h"
+#include "mm-shared.h"
 #include "mm-log.h"
 
+#define SHARED_PREFIX "libmm-shared"
+#define PLUGIN_PREFIX "libmm-plugin"
+
 static void initable_iface_init (GInitableIface *iface);
 
 G_DEFINE_TYPE_EXTENDED (MMPluginManager, mm_plugin_manager, G_TYPE_OBJECT, 0,
@@ -1629,9 +1633,10 @@ load_plugin (const gchar *path)
     }
 
     plugin = (*plugin_create_func) ();
-    if (plugin)
+    if (plugin) {
+        mm_dbg ("[plugin manager] loaded plugin '%s' from '%s'", mm_plugin_get_name (plugin), path_display);
         g_object_weak_ref (G_OBJECT (plugin), (GWeakNotify) g_module_close, module);
-    else
+    } else
         mm_warn ("[plugin manager] could not load plugin '%s': initialization failed", path_display);
 
 out:
@@ -1643,6 +1648,60 @@ out:
     return plugin;
 }
 
+static void
+load_shared (const gchar *path)
+{
+    GModule      *module;
+    gchar        *path_display;
+    const gchar **shared_name = NULL;
+    gint         *major_shared_version;
+    gint         *minor_shared_version;
+
+    /* Get printable UTF-8 string of the path */
+    path_display = g_filename_display_name (path);
+
+    module = g_module_open (path, G_MODULE_BIND_LAZY);
+    if (!module) {
+        mm_warn ("[plugin manager] could not load shared '%s': %s", path_display, g_module_error ());
+        goto out;
+    }
+
+    if (!g_module_symbol (module, "mm_shared_major_version", (gpointer *) &major_shared_version)) {
+        mm_warn ("[plugin manager] could not load shared '%s': Missing major version info", path_display);
+        goto out;
+    }
+
+    if (*major_shared_version != MM_SHARED_MAJOR_VERSION) {
+        mm_warn ("[plugin manager] could not load shared '%s': Shared major version %d, %d is required",
+                 path_display, *major_shared_version, MM_SHARED_MAJOR_VERSION);
+        goto out;
+    }
+
+    if (!g_module_symbol (module, "mm_shared_minor_version", (gpointer *) &minor_shared_version)) {
+        mm_warn ("[plugin manager] could not load shared '%s': Missing minor version info", path_display);
+        goto out;
+    }
+
+    if (*minor_shared_version != MM_SHARED_MINOR_VERSION) {
+        mm_warn ("[plugin manager] could not load shared '%s': Shared minor version %d, %d is required",
+                   path_display, *minor_shared_version, MM_SHARED_MINOR_VERSION);
+        goto out;
+    }
+
+    if (!g_module_symbol (module, "mm_shared_name", (gpointer *) &shared_name)) {
+        mm_warn ("[plugin manager] could not load shared '%s': Missing name", path_display);
+        goto out;
+    }
+
+    mm_dbg ("[plugin manager] loaded shared '%s' utils from '%s'", *shared_name, path_display);
+
+out:
+    if (module && !(*shared_name))
+        g_module_close (module);
+
+    g_free (path_display);
+}
+
 static gboolean
 load_plugins (MMPluginManager *self,
               GError **error)
@@ -1650,6 +1709,9 @@ load_plugins (MMPluginManager *self,
     GDir *dir = NULL;
     const gchar *fname;
     gchar *plugindir_display = NULL;
+    GList *shared_paths = NULL;
+    GList *plugin_paths = NULL;
+    GList *l;
 
     if (!g_module_supported ()) {
         g_set_error (error,
@@ -1674,21 +1736,26 @@ load_plugins (MMPluginManager *self,
     }
 
     while ((fname = g_dir_read_name (dir)) != NULL) {
-        gchar *path;
-        MMPlugin *plugin;
-
         if (!g_str_has_suffix (fname, G_MODULE_SUFFIX))
             continue;
+        if (g_str_has_prefix (fname, SHARED_PREFIX))
+            shared_paths = g_list_prepend (shared_paths, g_module_build_path (self->priv->plugin_dir, fname));
+        else if (g_str_has_prefix (fname, PLUGIN_PREFIX))
+            plugin_paths = g_list_prepend (plugin_paths, g_module_build_path (self->priv->plugin_dir, fname));
+    }
 
-        path = g_module_build_path (self->priv->plugin_dir, fname);
-        plugin = load_plugin (path);
-        g_free (path);
+    /* Load all shared utils */
+    for (l = shared_paths; l; l = g_list_next (l))
+        load_shared ((const gchar *)(l->data));
 
+    /* Load all plugins */
+    for (l = plugin_paths; l; l = g_list_next (l)) {
+        MMPlugin *plugin;
+
+        plugin = load_plugin ((const gchar *)(l->data));
         if (!plugin)
             continue;
 
-        mm_dbg ("[plugin manager] loaded plugin '%s'", mm_plugin_get_name (plugin));
-
         if (g_str_equal (mm_plugin_get_name (plugin), MM_PLUGIN_GENERIC_NAME))
             /* Generic plugin */
             self->priv->generic = plugin;
@@ -1719,6 +1786,8 @@ load_plugins (MMPluginManager *self,
             g_list_length (self->priv->plugins) + !!self->priv->generic);
 
 out:
+    g_list_free_full (shared_paths, g_free);
+    g_list_free_full (plugin_paths, g_free);
     if (dir)
         g_dir_close (dir);
     g_free (plugindir_display);

src/mm-shared.h

@@ -0,0 +1,35 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * 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:
+ *
+ * Copyright (C) 2019 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#ifndef MM_SHARED_H
+#define MM_SHARED_H
+
+#include <glib.h>
+#include <glib-object.h>
+
+#define MM_SHARED_MAJOR_VERSION 1
+#define MM_SHARED_MINOR_VERSION 0
+
+#if defined (G_HAVE_GNUC_VISIBILITY)
+#define VISIBILITY __attribute__((visibility("protected")))
+#else
+#define VISIBILITY
+#endif
+
+#define MM_SHARED_DEFINE_MAJOR_VERSION VISIBILITY int mm_shared_major_version = MM_SHARED_MAJOR_VERSION;
+#define MM_SHARED_DEFINE_MINOR_VERSION VISIBILITY int mm_shared_minor_version = MM_SHARED_MINOR_VERSION;
+#define MM_SHARED_DEFINE_NAME(NAME)    VISIBILITY const char *mm_shared_name = #NAME;
+
+#endif /* MM_SHARED_H */