ucm: Improve cset command parsing

The cset command parsing in ucm/main.c assumes implicitly that the
argument contains no space, thus an example below wouldn't work:
    cset "name='Input Select' Digital Mic"

This patch introduces a new internal API function
__snd_ctl_ascii_elem_id_parse() to improve the cset parser.

Reported-by: Tanu Kaskinen <tanu.kaskinen@digia.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

src/control/ctlparse.c

@@ -143,21 +143,19 @@ char *snd_ctl_ascii_elem_id_get(snd_ctl_elem_id_t *id)
 	return strdup(buf);
 }
 
-/**
+#ifndef DOC_HIDDEN
- * \brief parse ASCII string as CTL element identifier
+/* used by UCM parser, too */
- * \param dst destination CTL identifier
+int __snd_ctl_ascii_elem_id_parse(snd_ctl_elem_id_t *dst, const char *str,
- * \param str source ASCII string
+				  const char **ret_ptr)
- * \return zero on success, otherwise a negative error code
- */
-int snd_ctl_ascii_elem_id_parse(snd_ctl_elem_id_t *dst, const char *str)
 {
 	int c, size, numid;
+	int err = -EINVAL;
 	char *ptr;
 
-	while (*str == ' ' || *str == '\t')
+	while (isspace(*str))
 		str++;
 	if (!(*str))
-		return -EINVAL;
+		goto out;
 	snd_ctl_elem_id_set_interface(dst, SND_CTL_ELEM_IFACE_MIXER);	/* default */
 	while (*str) {
 		if (!strncasecmp(str, "numid=", 6)) {
@@ -165,7 +163,7 @@ int snd_ctl_ascii_elem_id_parse(snd_ctl_elem_id_t *dst, const char *str)
 			numid = atoi(str);
 			if (numid <= 0) {
 				fprintf(stderr, "amixer: Invalid numid %d\n", numid);
-				return -EINVAL;
+				goto out;
 			}
 			snd_ctl_elem_id_set_numid(dst, atoi(str));
 			while (isdigit(*str))
@@ -191,7 +189,7 @@ int snd_ctl_ascii_elem_id_parse(snd_ctl_elem_id_t *dst, const char *str)
 				snd_ctl_elem_id_set_interface(dst, SND_CTL_ELEM_IFACE_SEQUENCER);
 				str += 9;
 			} else {
-				return -EINVAL;
+				goto out;
 			}
 		} else if (!strncasecmp(str, "name=", 5)) {
 			char buf[64];
@@ -239,11 +237,33 @@ int snd_ctl_ascii_elem_id_parse(snd_ctl_elem_id_t *dst, const char *str)
 		if (*str == ',') {
 			str++;
 		} else {
+			/* when ret_ptr is given, allow to terminate gracefully
+			 * at the next space letter
+			 */
+			if (ret_ptr && isspace(*str))
+				break;
 			if (*str)
-				return -EINVAL;
+				goto out;
 		}
 	}			
-	return 0;
+	err = 0;
+
+ out:
+	if (ret_ptr)
+		*ret_ptr = str;
+	return err;
+}
+#endif
+
+/**
+ * \brief parse ASCII string as CTL element identifier
+ * \param dst destination CTL identifier
+ * \param str source ASCII string
+ * \return zero on success, otherwise a negative error code
+ */
+int snd_ctl_ascii_elem_id_parse(snd_ctl_elem_id_t *dst, const char *str)
+{
+	return __snd_ctl_ascii_elem_id_parse(dst, str, NULL);
 }
 
 static int get_ctl_enum_item_index(snd_ctl_t *handle,

src/ucm/main.c

@@ -31,6 +31,7 @@
  */
 
 #include "ucm_local.h"
+#include <ctype.h>
 #include <stdarg.h>
 #include <pthread.h>
 
@@ -158,9 +159,13 @@ static int open_ctl(snd_use_case_mgr_t *uc_mgr,
 	return 0;
 }
 
+extern int __snd_ctl_ascii_elem_id_parse(snd_ctl_elem_id_t *dst,
+					 const char *str,
+					 const char **ret_ptr);
+
 static int execute_cset(snd_ctl_t *ctl, char *cset)
 {
-	char *pos;
+	const char *pos;
 	int err;
 	snd_ctl_elem_id_t *id;
 	snd_ctl_elem_value_t *value;
@@ -170,16 +175,16 @@ static int execute_cset(snd_ctl_t *ctl, char *cset)
 	snd_ctl_elem_value_malloc(&value);
 	snd_ctl_elem_info_malloc(&info);
 
-	pos = strrchr(cset, ' ');
+	err = __snd_ctl_ascii_elem_id_parse(id, cset, &pos);
-	if (pos == NULL) {
+	if (err < 0)
+		goto __fail;
+	while (*pos && isspace(*pos))
+		pos++;
+	if (!*pos) {
 		uc_error("undefined value for cset >%s<", cset);
 		err = -EINVAL;
 		goto __fail;
 	}
-	*pos = '\0';
-	err = snd_ctl_ascii_elem_id_parse(id, cset);
-	if (err < 0)
-		goto __fail;
 	snd_ctl_elem_value_set_id(value, id);
 	snd_ctl_elem_info_set_id(info, id);
 	err = snd_ctl_elem_read(ctl, value);
@@ -188,7 +193,7 @@ static int execute_cset(snd_ctl_t *ctl, char *cset)
 	err = snd_ctl_elem_info(ctl, info);
 	if (err < 0)
 		goto __fail;
-	err = snd_ctl_ascii_value_parse(ctl, value, info, pos + 1);
+	err = snd_ctl_ascii_value_parse(ctl, value, info, pos);
 	if (err < 0)
 		goto __fail;
 	err = snd_ctl_elem_write(ctl, value);
@@ -196,9 +201,6 @@ static int execute_cset(snd_ctl_t *ctl, char *cset)
 		goto __fail;
 	err = 0;
       __fail:
-	if (pos != NULL)
-		*pos = ' ';
-
 	if (id != NULL)
 		free(id);
 	if (value != NULL)