compel: Add plugins header

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

compel/include/uapi/plugins.h

+#ifndef UAPI_COMPEL_PLUGIN_H__
+#define UAPI_COMPEL_PLUGIN_H__
+
+#define __init	__attribute__((__used__)) __attribute__ ((__section__(".compel.init")))
+#define __exit	__attribute__((__used__)) __attribute__ ((__section__(".compel.exit")))
+
+#ifndef __ASSEMBLY__
+
+typedef struct {
+	const char	*name;
+	int		(*init)(void);
+	void		(*exit)(void);
+} plugin_init_t;
+
+#define plugin_register(___desc)				\
+	static const plugin_init_t * const			\
+	___ptr__##___desc __init = &___desc;
+
+#define PLUGIN_REGISTER(___id, ___name, ___init, ___exit)	\
+	static const plugin_init_t __plugin_desc_##___id = {	\
+		.name = ___name,				\
+		.init = ___init,				\
+		.exit = ___exit,				\
+	};							\
+	plugin_register(__plugin_desc_##___id);
+
+#define PLUGIN_REGISTER_DUMMY(___id)				\
+	static const plugin_init_t __plugin_desc_##___id = {	\
+		.name = #___id,					\
+	};							\
+	plugin_register(__plugin_desc_##___id);
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* UAPI_COMPEL_PLUGIN_H__ */