modpost: file2alias: define size of alias

The size of the variable alias provided to do_entry functions are
currently not readily available. Thus hindering do_entry functions to
perform bounds checking.

Define the macro ALIAS_SIZE containing the size of the variable alias.
Signed-off-by: Mattias Jacobsson <2pi@mok.nu>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

scripts/mod/file2alias.c

@@ -50,6 +50,9 @@ struct devtable {
 	int (*do_entry)(const char *filename, void *symval, char *alias);
 };
 
+/* Size of alias provided to do_entry functions */
+#define ALIAS_SIZE 500
+
 /* Define a variable f that holds the value of field f of struct devid
  * based at address m.
  */
@@ -1303,7 +1306,7 @@ static void do_table(void *symval, unsigned long size,
 		     struct module *mod)
 {
 	unsigned int i;
-	char alias[500];
+	char alias[ALIAS_SIZE];
 
 	device_id_check(mod->name, device_id, size, id_size, symval);
 	/* Leave last one: it's the terminator. */