loader: Move to using linker sets to bring in optional bits

The graphics stuff is optional. When it is pulled into the system, we
use a linker set to initialize the lua bindings for it now.

Sponsored by:		Netflix
Reviewed by:		kevans, jhb
Differential Revision:	https://reviews.freebsd.org/D43906

2 files changed, 36 insertions, 0 deletions

diff --git a/stand/liblua/gfx_utils.c b/stand/liblua/gfx_utils.c
index d2d22738c929..8d2aaacbd688 100644
--- a/stand/liblua/gfx_utils.c
+++ b/stand/liblua/gfx_utils.c
@@ -245,3 +245,30 @@ void
 gfx_interp_md(void)
 {
 }
+
+static void
+gfx_init_md(lua_State *L)
+{
+	luaL_requiref(L, "gfx", luaopen_gfx, 1);
+	lua_pop(L, 1);	/* Remove lib */
+
+	/*
+	 * Add in the compatibility references in the loader table.  Doing it with
+	 * a pseudo-embedded script is easier than the raw calls.
+	 */
+	if (luaL_dostring(L,
+		"loader.fb_bezier = gfx.fb_bezier\n"
+		"loader.fb_drawrect = gfx.fb_drawrect\n"
+		"loader.fb_line = gfx.fb_line\n"
+		"loader.fb_putimage = gfx.fb_putimage\n"
+		"loader.fb_setpixel = gfx.fb_setpixel\n"
+		"loader.term_drawrect = gfx.term_drawrect\n"
+		"loader.term_putimage = gfx.term_putimage") != 0) {
+		lua_pop(L, 1);
+		const char *errstr = lua_tostring(L, -1);
+		errstr = errstr == NULL ? "unknown" : errstr;
+		printf("Error adding compat loader bindings: %s.\n", errstr);
+	}
+}
+
+LUA_COMPILE_SET(gfx_init_md);
diff --git a/stand/liblua/lutils.h b/stand/liblua/lutils.h
index c1fd6af496e5..522abfd3d0d4 100644
--- a/stand/liblua/lutils.h
+++ b/stand/liblua/lutils.h
@@ -30,3 +30,12 @@ int	luaopen_gfx(lua_State *);
 int	luaopen_loader(lua_State *);
 int	luaopen_io(lua_State *);
 int	luaopen_pager(lua_State *);
+
+#include <sys/linker_set.h>
+
+typedef void lua_init_md_t(lua_State *);
+#define LUA_COMPILE_SET(func)	\
+	DATA_SET(Xficl_compile_set, func)	/* XXX linker set know by ldscrips */
+#define LUA_FOREACH_SET(s) \
+	SET_FOREACH((s), Xficl_compile_set)
+SET_DECLARE(Xficl_compile_set, lua_init_md_t);