ucm: add cfg-save command

Allow to save whole (or partial) local UCM alsa library configuration
to a file.

Syntax (saves key1.key2 sub-tree):

	Sequence [
		cfg-save "/tmp/my-file.conf:key1.key2"
	]

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

src/ucm/main.c

@@ -573,6 +573,42 @@ static int execute_sysw(const char *sysw)
 	return 0;
 }
 
+static int execute_cfgsave(snd_use_case_mgr_t *uc_mgr, const char *filename)
+{
+	snd_config_t *config = uc_mgr->local_config;
+	char *file, *root;
+	snd_output_t *out;
+	int err = 0;
+
+	file = strdup(filename);
+	if (!file)
+		return -ENOMEM;
+	root = strchr(file, ':');
+	if (root) {
+		*root = '\0';
+		err = snd_config_search(config, root + 1, &config);
+		if (err < 0) {
+			uc_error("Unable to find subtree '%s'", root);
+			goto _err;
+		}
+	}
+
+	err = snd_output_stdio_open(&out, file, "w+");
+	if (err < 0) {
+		uc_error("unable to open file '%s': %s", file, snd_strerror(err));
+		goto _err;
+	}
+	err = snd_config_save(config, out);
+	snd_output_close(out);
+	if (err < 0) {
+		uc_error("unable to save configuration: %s", snd_strerror(err));
+		goto _err;
+	}
+_err:
+	free(file);
+	return err;
+}
+
 static int rewrite_device_value(snd_use_case_mgr_t *uc_mgr, const char *name, char **value)
 {
 	char *sval;
@@ -754,6 +790,11 @@ shell_retry:
 			if (err < 0)
 				goto __fail;
 			break;
+		case SEQUENCE_ELEMENT_TYPE_CFGSAVE:
+			err = execute_cfgsave(uc_mgr, s->data.cfgsave);
+			if (err < 0)
+				goto __fail;
+			break;
 		default:
 			uc_error("unknown sequence command %i", s->type);
 			break;

src/ucm/parser.c

@@ -924,6 +924,16 @@ exec:
 			goto exec;
 		}
 
+		if (strcmp(cmd, "cfg-save") == 0) {
+			curr->type = SEQUENCE_ELEMENT_TYPE_CFGSAVE;
+			err = parse_string_substitute3(uc_mgr, n, &curr->data.cfgsave);
+			if (err < 0) {
+				uc_error("error: sysw requires a string!");
+				return err;
+			}
+			continue;
+		}
+
 		if (strcmp(cmd, "comment") == 0)
 			goto skip;
 

src/ucm/ucm_local.h

@@ -56,6 +56,7 @@
 #define SEQUENCE_ELEMENT_TYPE_CTL_REMOVE	9
 #define SEQUENCE_ELEMENT_TYPE_CMPT_SEQ		10
 #define SEQUENCE_ELEMENT_TYPE_SYSSET		11
+#define SEQUENCE_ELEMENT_TYPE_CFGSAVE		12
 
 struct ucm_value {
         struct list_head list;
@@ -78,6 +79,7 @@ struct sequence_element {
 		char *cset;
 		char *exec;
 		char *sysw;
+		char *cfgsave;
 		struct component_sequence cmpt_seq; /* component sequence */
 	} data;
 };

src/ucm/utils.c

@@ -512,6 +512,9 @@ void uc_mgr_free_sequence_element(struct sequence_element *seq)
 	case SEQUENCE_ELEMENT_TYPE_SHELL:
 		free(seq->data.exec);
 		break;
+	case SEQUENCE_ELEMENT_TYPE_CFGSAVE:
+		free(seq->data.cfgsave);
+		break;
 	default:
 		break;
 	}