Refactor plugin registration and loading

Put different types of plugins (libwiretap, libwireshark) in different
subdirectories, give libwiretap and libwireshark init routines that
load the plugins, and have them scan the appropriate subdirectories
so that we don't even *try* to, for example, load libwireshark plugins
in programs that only use libwiretap.

Compiled plugins are stored in subfolders of the plugin folders, with
the subfolder name being the Wireshark minor version number (X.Y). There is
another hierarchical level for each Wireshark library (libwireshark, libwscodecs
and libwiretap).

The folder names are respectively plugins/X.Y/{epan,codecs,wiretap}.

Currently we only distribute "epan" (libwireshark) plugins.

Change-Id: I3438787a6f45820d64ba4ca91cbe3c8864708acb
Reviewed-on: https://code.wireshark.org/review/23983
Petri-Dish: João Valverde <j@v6e.pt>
Tested-by: Petri Dish Buildbot
Reviewed-by: João Valverde <j@v6e.pt>

1 files changed, 20 insertions, 84 deletions

diff --git a/epan/proto.c b/epan/proto.c
index 29d2d8d360..373eaa5af6 100644
--- a/epan/proto.c
+++ b/epan/proto.c
@@ -55,7 +55,6 @@
 #include "show_exception.h"
 #include "in_cksum.h"
 
-#include <wsutil/plugins.h>
 #include <wsutil/ws_printf.h> /* ws_debug_printf/ws_g_warning */
 #include <wsutil/glib-compat.h>
 
@@ -434,98 +433,37 @@ check_charset(const guint8 table[256], const char *str)
 }
 
 #ifdef HAVE_PLUGINS
-/*
- * List of dissector plugins.
- */
-typedef struct {
-	void (*register_protoinfo)(void);	/* routine to call to register protocol information */
-	void (*reg_handoff)(void);		/* routine to call to register dissector handoff */
-} dissector_plugin;
-
 static GSList *dissector_plugins = NULL;
 
-/*
- * Callback for each plugin found.
- */
-DIAG_OFF(pedantic)
-static gboolean
-check_for_dissector_plugin(GModule *handle)
+void
+proto_register_plugin(const proto_plugin *plug)
 {
-	gpointer gp;
-	void (*register_protoinfo)(void);
-	void (*reg_handoff)(void);
-	dissector_plugin *plugin;
-
-	/*
-	 * Do we have a register routine?
-	 */
-	if (g_module_symbol(handle, "plugin_register", &gp)) {
-		register_protoinfo = (void (*)(void))gp;
-	}
-	else {
-		register_protoinfo = NULL;
-	}
-
-	/*
-	 * Do we have a reg_handoff routine?
-	 */
-	if (g_module_symbol(handle, "plugin_reg_handoff", &gp)) {
-		reg_handoff = (void (*)(void))gp;
-	}
-	else {
-		reg_handoff = NULL;
+	if (!plug) {
+		/* XXX print useful warning */
+		return;
 	}
-
-	/*
-	 * If we have neither, we're not a dissector plugin.
-	 */
-	if (register_protoinfo == NULL && reg_handoff == NULL)
-		return FALSE;
-
-	/*
-	 * Add this one to the list of dissector plugins.
-	 */
-	plugin = (dissector_plugin *)g_malloc(sizeof (dissector_plugin));
-	plugin->register_protoinfo = register_protoinfo;
-	plugin->reg_handoff = reg_handoff;
-	dissector_plugins = g_slist_prepend(dissector_plugins, plugin);
-	return TRUE;
+	dissector_plugins = g_slist_prepend(dissector_plugins, (proto_plugin *)plug);
 }
-DIAG_ON(pedantic)
 
 static void
-register_dissector_plugin(gpointer data, gpointer user_data _U_)
+call_plugin_register_protoinfo(gpointer data, gpointer user_data _U_)
 {
-	dissector_plugin *plugin = (dissector_plugin *)data;
+	proto_plugin *plug = (proto_plugin *)data;
 
-	if (plugin->register_protoinfo)
-		(plugin->register_protoinfo)();
+	if (plug->register_protoinfo) {
+		plug->register_protoinfo();
+	}
 }
 
 static void
-reg_handoff_dissector_plugin(gpointer data, gpointer user_data _U_)
+call_plugin_register_handoff(gpointer data, gpointer user_data _U_)
 {
-	dissector_plugin *plugin = (dissector_plugin *)data;
+	proto_plugin *plug = (proto_plugin *)data;
 
-	if (plugin->reg_handoff)
-		(plugin->reg_handoff)();
-}
-
-/*
- * Register dissector plugin type.
- */
-void
-register_dissector_plugin_type(void)
-{
-	add_plugin_type("dissector", check_for_dissector_plugin);
-}
-
-static void
-dissector_plugin_destroy(gpointer p)
-{
-	g_free(p);
+	if (plug->register_handoff) {
+		plug->register_handoff();
+	}
 }
-
 #endif /* HAVE_PLUGINS */
 
 /* initialize data structures and register protocols and fields */
@@ -578,7 +516,7 @@ proto_init(void (register_all_protocols_func)(register_cb cb, gpointer client_da
 	   plugins. */
 	if (cb)
 		(*cb)(RA_PLUGIN_REGISTER, NULL, client_data);
-	g_slist_foreach(dissector_plugins, register_dissector_plugin, NULL);
+	g_slist_foreach(dissector_plugins, call_plugin_register_protoinfo, NULL);
 #endif
 
 	/* Now call the "handoff registration" routines of all built-in
@@ -591,7 +529,7 @@ proto_init(void (register_all_protocols_func)(register_cb cb, gpointer client_da
 	/* Now do the same with plugins. */
 	if (cb)
 		(*cb)(RA_PLUGIN_HANDOFF, NULL, client_data);
-	g_slist_foreach(dissector_plugins, reg_handoff_dissector_plugin, NULL);
+	g_slist_foreach(dissector_plugins, call_plugin_register_handoff, NULL);
 #endif
 
 	/* sort the protocols by protocol name */
@@ -686,10 +624,8 @@ proto_cleanup(void)
 	proto_cleanup_base();
 
 #ifdef HAVE_PLUGINS
-	if (dissector_plugins) {
-		g_slist_free_full(dissector_plugins, dissector_plugin_destroy);
-		dissector_plugins = NULL;
-	}
+	g_slist_free(dissector_plugins);
+	dissector_plugins = NULL;
 #endif
 }