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From: Emil Velikov via B4 Relay <devnull+emil.l.velikov.gmail.com@kernel.org>
Date: Mon, 29 Jan 2024 14:44:16 +0000
Subject: [PATCH BlueZ v4 2/8] obexd: factor out external plugin support
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Message-Id: <20240129-rm-ext-plugins-v4-2-bfd1e08c7f99@gmail.com>
References: <20240129-rm-ext-plugins-v4-0-bfd1e08c7f99@gmail.com>
In-Reply-To: <20240129-rm-ext-plugins-v4-0-bfd1e08c7f99@gmail.com>
To: linux-bluetooth@vger.kernel.org
Cc: Emil Velikov <emil.velikov@collabora.com>
Reply-To: <emil.l.velikov@gmail.com>

From: Emil Velikov <emil.velikov@collabora.com>

As a whole all plugins should be built-in, otherwise they would be using
internal, undocumented, unversioned, unstable API.

Flesh out the external plugin support into a few blocks and simplify the
normal path. Guard the external plugin support behind a runtime check,
which will be dead-code eliminated in the default case.

Hide the internal API (omit export-dynamic) when built without external
plugins.
---
 Makefile.obexd     |  2 ++
 obexd/src/obexd.h  |  2 +-
 obexd/src/plugin.c | 89 ++++++++++++++++++++++++++++++++++++------------------
 obexd/src/plugin.h |  4 +++
 4 files changed, 66 insertions(+), 31 deletions(-)

diff --git a/Makefile.obexd b/Makefile.obexd
index 363295d0e..0e50b1fa4 100644
--- a/Makefile.obexd
+++ b/Makefile.obexd
@@ -92,7 +92,9 @@ obexd_src_obexd_LDADD = lib/libbluetooth-internal.la \
 			$(ICAL_LIBS) $(DBUS_LIBS) $(LIBEBOOK_LIBS) \
 			$(LIBEDATASERVER_LIBS) $(GLIB_LIBS) -ldl
 
+if EXTERNAL_PLUGINS
 obexd_src_obexd_LDFLAGS = $(AM_LDFLAGS) -Wl,--export-dynamic
+endif
 
 obexd_src_obexd_CPPFLAGS = $(AM_CPPFLAGS) $(GLIB_CFLAGS) $(DBUS_CFLAGS) \
 				$(ICAL_CFLAGS) -DOBEX_PLUGIN_BUILTIN \
diff --git a/obexd/src/obexd.h b/obexd/src/obexd.h
index fe312a65b..af5265da5 100644
--- a/obexd/src/obexd.h
+++ b/obexd/src/obexd.h
@@ -18,7 +18,7 @@
 #define OBEX_MAS	(1 << 8)
 #define OBEX_MNS	(1 << 9)
 
-gboolean plugin_init(const char *pattern, const char *exclude);
+void plugin_init(const char *pattern, const char *exclude);
 void plugin_cleanup(void);
 
 gboolean manager_init(void);
diff --git a/obexd/src/plugin.c b/obexd/src/plugin.c
index a3eb24753..14327782d 100644
--- a/obexd/src/plugin.c
+++ b/obexd/src/plugin.c
@@ -34,6 +34,8 @@
 #define PLUGINFLAG (RTLD_NOW)
 #endif
 
+#define IS_ENABLED(x) (x)
+
 static GSList *plugins = NULL;
 
 struct obex_plugin {
@@ -41,7 +43,8 @@ struct obex_plugin {
 	const struct obex_plugin_desc *desc;
 };
 
-static gboolean add_plugin(void *handle, const struct obex_plugin_desc *desc)
+static gboolean add_external_plugin(void *handle,
+					const struct obex_plugin_desc *desc)
 {
 	struct obex_plugin *plugin;
 
@@ -66,6 +69,25 @@ static gboolean add_plugin(void *handle, const struct obex_plugin_desc *desc)
 	return TRUE;
 }
 
+static void add_plugin(const struct obex_plugin_desc *desc)
+{
+	struct obex_plugin *plugin;
+
+	plugin = g_try_new0(struct obex_plugin, 1);
+	if (plugin == NULL)
+		return;
+
+	plugin->desc = desc;
+
+	if (desc->init() < 0) {
+		g_free(plugin);
+		return;
+	}
+
+	plugins = g_slist_append(plugins, plugin);
+	DBG("Plugin %s loaded", desc->name);
+}
+
 static gboolean check_plugin(const struct obex_plugin_desc *desc,
 				char **patterns, char **excludes)
 {
@@ -93,42 +115,22 @@ static gboolean check_plugin(const struct obex_plugin_desc *desc,
 }
 
 
-#include "builtin.h"
-
-gboolean plugin_init(const char *pattern, const char *exclude)
+static void external_plugin_init(char **patterns, char **excludes)
 {
-	char **patterns = NULL;
-	char **excludes = NULL;
 	GDir *dir;
 	const char *file;
-	unsigned int i;
 
-	if (strlen(PLUGINDIR) == 0)
-		return FALSE;
+	info("Using external plugins is not officially supported.\n");
+	info("Consider upstreaming your plugins into the BlueZ project.");
 
-	if (pattern)
-		patterns = g_strsplit_set(pattern, ":, ", -1);
-
-	if (exclude)
-		excludes = g_strsplit_set(exclude, ":, ", -1);
-
-	DBG("Loading builtin plugins");
-
-	for (i = 0; __obex_builtin[i]; i++) {
-		if (check_plugin(__obex_builtin[i],
-					patterns, excludes) == FALSE)
-			continue;
-
-		add_plugin(NULL,  __obex_builtin[i]);
-	}
+	if (strlen(PLUGINDIR) == 0)
+		return;
 
 	DBG("Loading plugins %s", PLUGINDIR);
 
 	dir = g_dir_open(PLUGINDIR, 0, NULL);
 	if (!dir) {
-		g_strfreev(patterns);
-		g_strfreev(excludes);
-		return FALSE;
+		return;
 	}
 
 	while ((file = g_dir_read_name(dir)) != NULL) {
@@ -164,15 +166,42 @@ gboolean plugin_init(const char *pattern, const char *exclude)
 			continue;
 		}
 
-		if (add_plugin(handle, desc) == FALSE)
+		if (add_external_plugin(handle, desc) == FALSE)
 			dlclose(handle);
 	}
 
 	g_dir_close(dir);
+}
+
+#include "builtin.h"
+
+void plugin_init(const char *pattern, const char *exclude)
+{
+	char **patterns = NULL;
+	char **excludes = NULL;
+	unsigned int i;
+
+	if (pattern)
+		patterns = g_strsplit_set(pattern, ":, ", -1);
+
+	if (exclude)
+		excludes = g_strsplit_set(exclude, ":, ", -1);
+
+	DBG("Loading builtin plugins");
+
+	for (i = 0; __obex_builtin[i]; i++) {
+		if (check_plugin(__obex_builtin[i],
+					patterns, excludes) == FALSE)
+			continue;
+
+		add_plugin(__obex_builtin[i]);
+	}
+
+	if IS_ENABLED(EXTERNAL_PLUGINS)
+		external_plugin_init(patterns, excludes);
+
 	g_strfreev(patterns);
 	g_strfreev(excludes);
-
-	return TRUE;
 }
 
 void plugin_cleanup(void)
diff --git a/obexd/src/plugin.h b/obexd/src/plugin.h
index a91746cbc..e1756b9bf 100644
--- a/obexd/src/plugin.h
+++ b/obexd/src/plugin.h
@@ -20,10 +20,14 @@ struct obex_plugin_desc {
 			#name, init, exit \
 		};
 #else
+#if EXTERNAL_PLUGINS
 #define OBEX_PLUGIN_DEFINE(name,init,exit) \
 		extern struct obex_plugin_desc obex_plugin_desc \
 				__attribute__ ((visibility("default"))); \
 		const struct obex_plugin_desc obex_plugin_desc = { \
 			#name, init, exit \
 		};
+#else
+#error "Requested non built-in plugin, while external plugins is disabled"
+#endif
 #endif

-- 
2.43.0