kconfig: remove 'const' from the return type of sym_escape_string_value()

sym_escape_string_value() returns a malloc'ed memory, but as
(const char *). So, it must be casted to (void *) when it is free'd.
This is odd.

The return type of sym_escape_string_value() should be (char *).

I exploited that free(NULL) has no effect.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/conf.c

@@ -647,17 +647,16 @@ static void check_conf(struct menu *menu)
 		switch (input_mode) {
 		case listnewconfig:
 			if (sym->name) {
-				const char *str;
+				const char *val = sym_get_string_value(sym);
+				char *escaped = NULL;
 
 				if (sym->type == S_STRING) {
-					str = sym_get_string_value(sym);
-					str = sym_escape_string_value(str);
-					printf("%s%s=%s\n", CONFIG_, sym->name, str);
-					free((void *)str);
-				} else {
-					str = sym_get_string_value(sym);
-					printf("%s%s=%s\n", CONFIG_, sym->name, str);
+					escaped = sym_escape_string_value(val);
+					val = escaped;
 				}
+
+				printf("%s%s=%s\n", CONFIG_, sym->name, val);
+				free(escaped);
 			}
 			break;
 		case helpnewconfig:

scripts/kconfig/confdata.c

@@ -728,21 +728,22 @@ static struct conf_printer header_printer_cb =
 static void conf_write_symbol(FILE *fp, struct symbol *sym,
 			      struct conf_printer *printer, void *printer_arg)
 {
-	const char *str;
+	const char *val;
+	char *escaped = NULL;
 
-	switch (sym->type) {
-	case S_UNKNOWN:
-		break;
-	case S_STRING:
-		str = sym_get_string_value(sym);
-		str = sym_escape_string_value(str);
-		printer->print_symbol(fp, sym, str, printer_arg);
-		free((void *)str);
-		break;
-	default:
-		str = sym_get_string_value(sym);
-		printer->print_symbol(fp, sym, str, printer_arg);
+	if (sym->type == S_UNKNOWN)
+		return;
+
+	val = sym_get_string_value(sym);
+
+	if (sym->type == S_STRING) {
+		escaped = sym_escape_string_value(val);
+		val = escaped;
 	}
+
+	printer->print_symbol(fp, sym, val, printer_arg);
+
+	free(escaped);
 }
 
 static void

scripts/kconfig/lkc_proto.h

@@ -18,7 +18,7 @@ extern struct symbol * symbol_hash[SYMBOL_HASHSIZE];
 
 struct symbol * sym_lookup(const char *name, int flags);
 struct symbol * sym_find(const char *name);
-const char * sym_escape_string_value(const char *in);
+char *sym_escape_string_value(const char *in);
 struct symbol ** sym_re_search(const char *pattern);
 const char * sym_type_name(enum symbol_type type);
 void sym_calc_value(struct symbol *sym);

scripts/kconfig/symbol.c

@@ -871,7 +871,8 @@ struct symbol *sym_find(const char *name)
 	return symbol;
 }
 
-const char *sym_escape_string_value(const char *in)
+/* The returned pointer must be freed on the caller side */
+char *sym_escape_string_value(const char *in)
 {
 	const char *p;
 	size_t reslen;