parasite: Macro for getting parasite symbols

Same as previous patch -- easier to read and possible
to use tags.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/parasite.h

@@ -123,16 +123,8 @@ struct parasite_tty_args {
 	int	st_excl;
 };
 
-/*
- * Some useful offsets
- */
-
-#define PARASITE_ARGS_ADDR(start)				\
-	((start) + parasite_blob_offset____export_parasite_args)
-#define PARASITE_CMD_ADDR(start)				\
-	((start) + parasite_blob_offset____export_parasite_cmd)
-#define PARASITE_HEAD_ADDR(start)				\
-	((start) + parasite_blob_offset____export_parasite_head_start)
+/* the parasite prefix is added by gen_offsets.sh */
+#define parasite_sym(pblob, name) ((void *)(pblob) + parasite_blob_offset__##name)
 
 #endif /* !__ASSEMBLY__ */
 #endif /* CR_PARASITE_H_ */

parasite-syscall.c

@@ -850,9 +850,9 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, struct pstree_item *item,
 	memcpy(ctl->local_map, parasite_blob, sizeof(parasite_blob));
 
 	/* Setup the rest of a control block */
-	ctl->parasite_ip	= PARASITE_HEAD_ADDR((unsigned long)ctl->remote_map);
-	ctl->addr_cmd		= (unsigned int *)PARASITE_CMD_ADDR((unsigned long)ctl->local_map);
-	ctl->addr_args		= (void *)PARASITE_ARGS_ADDR((unsigned long)ctl->local_map);
+	ctl->parasite_ip	= (unsigned long)parasite_sym(ctl->remote_map, __export_parasite_head_start);
+	ctl->addr_cmd		= parasite_sym(ctl->local_map, __export_parasite_cmd);
+	ctl->addr_args		= parasite_sym(ctl->local_map, __export_parasite_args);
 
 	ret = parasite_init(ctl, pid, item->nr_threads);
 	if (ret) {