cbi: Do not add tags if data size is zero

This change skips adding a tag to CBI if the size of its data is
zero. Thus, callers of optional tags do not need to worry about
checking if a tag should be added. It is taken care of within
cbi_set_data.

BUG=b:124282048
BRANCH=None
TEST=Verified that MODEL_ID no longer shows up in cbi data.

Change-Id: Id0c3da87a1479f5c52bd7b4f06840e5b4476b3d6
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1506439
Commit-Ready: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/common/cbi.c b/common/cbi.c
index e4dc001184..8517506eec 100644
--- a/common/cbi.c
+++ b/common/cbi.c
@@ -34,6 +34,14 @@ uint8_t *cbi_set_data(uint8_t *p, enum cbi_data_tag tag,
 		      const void *buf, int size)
 {
 	struct cbi_data *d = (struct cbi_data *)p;
+
+	/*
+	 * If size of the data to be added is zero, then no need to add the tag
+	 * as well.
+	 */
+	if (size == 0)
+		return p;
+
 	d->tag = tag;
 	d->size = size;
 	memcpy(d->value, buf, size);
@@ -185,12 +193,13 @@ int cbi_set_board_info(enum cbi_data_tag tag, const uint8_t *buf, uint8_t size)
 	}
 
 	if (!d) {
+		uint8_t *p;
 		/* Not found. Check if new item would fit */
 		if (sizeof(cbi) < head->total_size + sizeof(*d) + size)
 			return EC_ERROR_OVERFLOW;
 		/* Append new item */
-		cbi_set_data(&cbi[head->total_size], tag, buf, size);
-		head->total_size += (sizeof(*d) + size);
+		p = cbi_set_data(&cbi[head->total_size], tag, buf, size);
+		head->total_size = p - cbi;
 	} else {
 		/* Overwrite existing item */
 		memcpy(d->value, buf, d->size);