mok variables: add a format callback

This adds a member to the mok_state_variable struct to provide a
callback function for formatting external data.  It basically has
snprintf()-like semantics for filling the buffer, but without the actual
printf-like formatting bits.

Signed-off-by: Peter Jones <pjones@redhat.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/mok.c b/mok.c
index 2778cd05..67a798a3 100644
--- a/mok.c
+++ b/mok.c
@@ -985,8 +985,22 @@ EFI_STATUS import_one_mok_state(struct mok_state_variable *v,
 		}
 	}
 
+	if (v->format) {
+		v->data_size = v->format(NULL, 0, v);
+		if (v->data_size > 0) {
+			v->data = AllocatePool(v->data_size);
+			if (!v->data) {
+				perror(L"Could not allocate %lu bytes for %s\n",
+				       v->data_size, v->name);
+				return EFI_OUT_OF_RESOURCES;
+			}
+		}
+		v->format(v->data, v->data_size, v);
+	}
+
 	if (!v->data && !v->data_size &&
-	    (v->flags & MOK_VARIABLE_CONFIG_ONLY)) {
+	    (v->flags & MOK_VARIABLE_CONFIG_ONLY) &&
+	    !v->format) {
 		efi_status = get_variable_attr(v->name,
 					       &v->data, &v->data_size,
 					       *v->guid, &attrs);