test-qga: Clean up how we test QGA synchronization

To permit recovering from arbitrary JSON parse errors, the JSON parser
resets itself on lexical errors.  We recommend sending a 0xff byte for
that purpose, and test-qga covers this usage since commit 5229564b83.
That commit had to add an ugly hack to qmp_fd_vsend() to make capable
of sending this byte (it's designed to send only valid JSON).

The previous commit added a way to send arbitrary text.  Put that to
use for this purpose, and drop the hack from qmp_fd_vsend().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-8-armbru@redhat.com>

tests/libqtest.c

@@ -507,16 +507,6 @@ void qmp_fd_vsend(int fd, const char *fmt, va_list ap)
 {
     QObject *qobj;
 
-    /*
-     * qobject_from_vjsonf_nofail() chokes on leading 0xff as invalid
-     * JSON, but tests/test-qga.c needs to send that to test QGA
-     * synchronization
-     */
-    if (*fmt == '\377') {
-        socket_send(fd, fmt, 1);
-        fmt++;
-    }
-
     /* Going through qobject ensures we escape strings properly */
     qobj = qobject_from_vjsonf_nofail(fmt, ap);
 
@@ -604,23 +594,36 @@ void qtest_qmp_send(QTestState *s, const char *fmt, ...)
     va_end(ap);
 }
 
-void qtest_qmp_send_raw(QTestState *s, const char *fmt, ...)
+void qmp_fd_vsend_raw(int fd, const char *fmt, va_list ap)
 {
     bool log = getenv("QTEST_LOG") != NULL;
-    va_list ap;
-    char *str;
-
-    va_start(ap, fmt);
-    str = g_strdup_vprintf(fmt, ap);
-    va_end(ap);
+    char *str = g_strdup_vprintf(fmt, ap);
 
     if (log) {
         fprintf(stderr, "%s", str);
     }
-    socket_send(s->qmp_fd, str, strlen(str));
+    socket_send(fd, str, strlen(str));
     g_free(str);
 }
 
+void qmp_fd_send_raw(int fd, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    qmp_fd_vsend_raw(fd, fmt, ap);
+    va_end(ap);
+}
+
+void qtest_qmp_send_raw(QTestState *s, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    qmp_fd_vsend_raw(s->qmp_fd, fmt, ap);
+    va_end(ap);
+}
+
 QDict *qtest_qmp_eventwait_ref(QTestState *s, const char *event)
 {
     QDict *response;

tests/libqtest.h

@@ -959,6 +959,8 @@ static inline int64_t clock_set(int64_t val)
 QDict *qmp_fd_receive(int fd);
 void qmp_fd_vsend(int fd, const char *fmt, va_list ap) GCC_FMT_ATTR(2, 0);
 void qmp_fd_send(int fd, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
+void qmp_fd_send_raw(int fd, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
+void qmp_fd_vsend_raw(int fd, const char *fmt, va_list ap) GCC_FMT_ATTR(2, 0);
 QDict *qmp_fdv(int fd, const char *fmt, va_list ap) GCC_FMT_ATTR(2, 0);
 QDict *qmp_fd(int fd, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
 

tests/test-qga.c

@@ -147,8 +147,9 @@ static void test_qga_sync_delimited(gconstpointer fix)
     unsigned char c;
     QDict *ret;
 
+    qmp_fd_send_raw(fixture->fd, "\xff");
     qmp_fd_send(fixture->fd,
-                "\xff{'execute': 'guest-sync-delimited',"
+                "{'execute': 'guest-sync-delimited',"
                 " 'arguments': {'id': %u } }",
                 r);