qapi-commands.py: Don't call the output marshal on error
Today we generate something like this:
int qmp_marshal_input_query_foo(...)
...
retval = qmp_query_foo(errp);
qmp_marshal_output_query_foo(retval, ret, errp);
...
However, if qmp_query_foo() fails 'retval' will probably be NULL,
which can cause a segfault as not all visitors check if 'retval'
is valid.
This commit fixes that by changing the code generator to only
call the output marshal if qmp_query_foo() succeeds, like this:
retval = qmp_query_foo(errp);
if (!error_is_set(errp)) {
qmp_marshal_output_query_foo(retval, ret, errp);
}
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index c947ba4..f7def16 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -62,7 +62,9 @@
name=c_var(name), args=arglist, retval=retval).rstrip()
if ret_type:
ret += "\n" + mcgen(''''
-%(marshal_output_call)s
+if (!error_is_set(errp)) {
+ %(marshal_output_call)s
+}
''',
marshal_output_call=gen_marshal_output_call(name, ret_type)).rstrip()
pop_indent(indent)
