topology: do not call strtol directly

Introduce safe_strtol_base() function and redirects all
strtol calls there. Also, improve error and value handling
in callers.

BugLink: #187
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

src/topology/data.c

@@ -414,12 +414,8 @@ static int write_hex(char *buf, char *str, int width)
 	void *p = &val;
 
         errno = 0;
-	val = strtol(str, NULL, 16);
-
-	if ((errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
-		|| (errno != 0 && val == 0)) {
+	if (safe_strtol_base(str, &val, 16) < 0)
 		return -EINVAL;
-        }
 
 	switch (width) {
 	case 1:

src/topology/ops.c

@@ -34,15 +34,22 @@ static const struct map_elem control_map[] = {
 
 static int lookup_ops(const char *c)
 {
-	unsigned int i;
+	int i;
+	long ret;
 
-	for (i = 0; i < ARRAY_SIZE(control_map); i++) {
+	for (i = 0; i < (int)ARRAY_SIZE(control_map); i++) {
 		if (strcmp(control_map[i].name, c) == 0)
 			return control_map[i].id;
 	}
 
 	/* cant find string name in our table so we use its ID number */
-	return strtol(c, NULL, 0);
+	i = safe_strtol(c, &ret);
+	if (i < 0) {
+		SNDERR("wrong kcontrol ops value string '%s'", c);
+		return i;
+	}
+
+	return ret;
 }
 
 const char *tplg_ops_name(int type)

src/topology/parser.c

@@ -21,6 +21,25 @@
 #include "list.h"
 #include "tplg_local.h"
 
+/*
+ * Safe strtol call
+ */
+int safe_strtol_base(const char *str, long *val, int base)
+{
+	char *end;
+	long v;
+	if (!*str)
+		return -EINVAL;
+	errno = 0;
+	v = strtol(str, &end, base);
+	if (errno)
+		return -errno;
+	if (*end)
+		return -EINVAL;
+	*val = v;
+	return 0;
+}
+
 /*
  * Get integer value
  */
@@ -35,24 +54,23 @@ int tplg_get_integer(snd_config_t *n, int *val, int base)
 		err = snd_config_get_integer(n, &lval);
 		if (err < 0)
 			return err;
-		if (lval < INT_MIN || lval > INT_MAX)
-			return -ERANGE;
-		*val = lval;
-		return err;
+		goto __retval;
 	case SND_CONFIG_TYPE_STRING:
 		err = snd_config_get_string(n, &str);
 		if (err < 0)
 			return err;
-		errno = 0;
-		*val = strtol(str, NULL, base);
-		if (errno == ERANGE)
-			return -ERANGE;
-		if (errno && *val == 0)
-			return -EINVAL;
-		return 0;
+		err = safe_strtol_base(str, &lval, base);
+		if (err < 0)
+			return err;
+		goto __retval;
 	default:
 		return -EINVAL;
 	}
+  __retval:
+	if (lval < INT_MIN || lval > INT_MAX)
+		return -ERANGE;
+	*val = lval;
+	return 0;
 }
 
 /*