From: Jaroslav Kysela <perex@perex.cz>
Date: Tue, 6 Oct 2020 08:40:40 +0000 (+0200)
Subject: ucm: add a check for the empty configuration
X-Git-Tag: v1.2.4~16
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=22d5ca8b6bcd767d09de11b0afdd82c618f4be24;p=alsa-lib.git

ucm: add a check for the empty configuration

Return an error if the UCM configuration is empty (no verbs
or no boot sequence).

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---

diff --git a/src/ucm/main.c b/src/ucm/main.c
index 9e43ac66..00b41708 100644
--- a/src/ucm/main.c
+++ b/src/ucm/main.c
@@ -568,6 +568,20 @@ static int import_master_config(snd_use_case_mgr_t *uc_mgr)
 	return add_auto_values(uc_mgr);
 }
 
+/**
+ * \brief Check, if the UCM configuration is empty
+ * \param uc_mgr Use case Manager
+ * \return zero on success, otherwise a negative error code
+ */
+static int check_empty_configuration(snd_use_case_mgr_t *uc_mgr)
+{
+	if (!list_empty(&uc_mgr->verb_list))
+		return 0;
+	if (!list_empty(&uc_mgr->once_list))
+		return 0;
+	return -ENXIO;
+}
+
 /**
  * \brief Universal find - string in a list
  * \param list List of structures
@@ -981,14 +995,20 @@ int snd_use_case_mgr_open(snd_use_case_mgr_t **uc_mgr,
 	err = import_master_config(mgr);
 	if (err < 0) {
 		uc_error("error: failed to import %s use case configuration %d",
-			card_name, err);
-		goto err;
+			 card_name, err);
+		goto _err;
+	}
+
+	err = check_empty_configuration(mgr);
+	if (err < 0) {
+		uc_error("error: failed to import %s (empty configuration)", card_name);
+		goto _err;
 	}
 
 	*uc_mgr = mgr;
 	return 0;
 
-err:
+_err:
 	uc_mgr_free(mgr);
 	return err;
 }