[Qemu-devel] [PATCH 3/7] libqtest: add QTEST_LOG for debugging qtest testcases

["Marc Marí" <marc.mari.barcelo@gmail.com>]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Marí <marc.mari.barcelo@gmail.com>
---
 tests/libqtest.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/tests/libqtest.c b/tests/libqtest.c
index 98e8f4b..056275d 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -167,11 +167,12 @@ QTestState *qtest_init(const char *extra_args)
     if (s->qemu_pid == 0) {
         command = g_strdup_printf("exec %s "
                                   "-qtest unix:%s,nowait "
-                                  "-qtest-log /dev/null "
+                                  "-qtest-log %s "
                                   "-qmp unix:%s,nowait "
                                   "-machine accel=qtest "
                                   "-display none "
                                   "%s", qemu_binary, socket_path,
+                                  getenv("QTEST_LOG") ? "/dev/fd/2" : "/dev/null",
                                   qmp_socket_path,
                                   extra_args ?: "");
         execlp("/bin/sh", "sh", "-c", command, NULL);
@@ -397,10 +398,18 @@ QDict *qtest_qmpv(QTestState *s, const char *fmt, va_list ap)
 
     /* No need to send anything for an empty QObject.  */
     if (qobj) {
+        size_t len;
+        int log = getenv("QTEST_LOG") != NULL;
         QString *qstr = qobject_to_json(qobj);
         const char *str = qstring_get_str(qstr);
         size_t size = qstring_get_length(qstr);
 
+        if (log) {
+            len = write(2, str, size);
+            if (len != size) {
+                fprintf(stderr, "Could not log\n");
+            }
+        }
         /* Send QMP request */
         socket_send(s->qmp_fd, str, size);
 
-- 
1.7.10.4