Make ds_cstr() always null-terminate the string.

Most of the time the string in "struct ds" is
null-terminated, but there seem to be a few corner cases
where it is not.  Make ds_cstr() always put in the null
terminator, for safety.

Thanks to Justin for pointing out the problem.

diff --git a/lib/dynamic-string.c b/lib/dynamic-string.c
index 2fe8cfb..1df85ac 100644 (file)
--- a/lib/dynamic-string.c
+++ b/lib/dynamic-string.c
@@ -177,8 +177,8 @@ ds_cstr(struct ds *ds)
 {
     if (!ds->string) {
         ds_reserve(ds, 0);
-        ds->string[0] = '\0';
     }
+    ds->string[ds->length] = '\0';
     return ds->string;
 }