[PATCH 29/44] security: blobgen: add easy way to check for existent providers

[Ahmad Fatoum <a.fatoum@barebox.org>]

blobgen_get() expects the user to name the blobgen instance to be used.
For general informational purposes, it would be nice to just check if
any provider is registered at all, so make that possible by accepting a
NULL filter argument.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 include/blobgen.h  |  7 +++++++
 security/blobgen.c | 18 +++++++++++-------
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/include/blobgen.h b/include/blobgen.h
index 9f8876cee045..00674ef40f73 100644
--- a/include/blobgen.h
+++ b/include/blobgen.h
@@ -44,7 +44,14 @@ struct blobgen {
 
 int blob_gen_register(struct device *dev, struct blobgen *bg);
 
+#ifdef CONFIG_BLOBGEN
 struct blobgen *blobgen_get(const char *name);
+#else
+static inline struct blobgen *blobgen_get(const char *name)
+{
+	return NULL;
+}
+#endif
 
 int blob_encrypt(struct blobgen *blg, const char *modifier, const void *plain,
 		 int plainsize, void **blob, int *blobsize);
diff --git a/security/blobgen.c b/security/blobgen.c
index 0a4e192a271f..df42c8f6f1bc 100644
--- a/security/blobgen.c
+++ b/security/blobgen.c
@@ -50,24 +50,28 @@ int blob_gen_register(struct device *dev, struct blobgen *bg)
 
 /**
  * blobgen_get - get a blob generator of given name
- * @name: The name of the blob generator to look for
+ * @name: The name of the blob generator to look for or NULL
  *
- * Finds a blob generator by name and returns it. Returns NULL if none is found.
+ * Finds a blob generator by name and returns it.
+ * If name is NULL, returns the first blob generator encountered.
+ * Returns NULL if none is found.
  */
 struct blobgen *blobgen_get(const char *name)
 {
-	struct device *dev;
+	struct device *dev = NULL;
 	struct blobgen *bg;
 
 	if (!name)
 		return bg_default;
 
-	dev = get_device_by_name(name);
-	if (!dev)
-		return NULL;
+	if (name) {
+		dev = get_device_by_name(name);
+		if (!dev)
+			return NULL;
+	}
 
 	list_for_each_entry(bg, &blobs, list) {
-		if (dev == &bg->dev)
+		if (!dev || dev == &bg->dev)
 			return bg;
 	}
 
-- 
2.39.5