Allow boot code to be smaller than what the scheme expects.

This effectively changes the boot code size to be an upper
bound and makes the interface more flexible.

1 files changed, 6 insertions, 1 deletions

diff --git a/sys/geom/part/g_part_gpt.c b/sys/geom/part/g_part_gpt.c
index 7bdfa07..13a4561 100644
--- a/sys/geom/part/g_part_gpt.c
+++ b/sys/geom/part/g_part_gpt.c
@@ -374,9 +374,14 @@ static int
 g_part_gpt_bootcode(struct g_part_table *basetable, struct g_part_parms *gpp)
 {
 	struct g_part_gpt_table *table;
+	size_t codesz;
 
+	codesz = DOSPARTOFF;
 	table = (struct g_part_gpt_table *)basetable;
-	bcopy(gpp->gpp_codeptr, table->mbr, DOSPARTOFF);
+	bzero(table->mbr, codesz);
+	codesz = MIN(codesz, gpp->gpp_codesize);
+	if (codesz > 0)
+		bcopy(gpp->gpp_codeptr, table->mbr, codesz);
 	return (0);
 }