tests/qtest: Use exit-with-parent=on in qtest invocations

Previously libqtest.c set PR_SET_PDEATHSIG (or the equivalent on
FreeBSD) after forking the qemu subprocess.  However we can get the
same behaviour now by using the new -run-with exit-with-parent=on
flag, on platforms that support it.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

tests/qtest/libqtest.c

@@ -33,6 +33,7 @@
 #include "qemu/accel.h"
 #include "qemu/ctype.h"
 #include "qemu/cutils.h"
+#include "qemu/exit-with-parent.h"
 #include "qemu/sockets.h"
 #include "qobject/qdict.h"
 #include "qobject/qjson.h"
@@ -433,24 +434,6 @@ static QTestState *qtest_spawn_qemu(const char *qemu_bin, const char *args,
 #ifndef _WIN32
     pid = fork();
     if (pid == 0) {
-#ifdef __linux__
-        /*
-         * Although we register a ABRT handler to kill off QEMU
-         * when g_assert() triggers, we want an extra safety
-         * net. The QEMU process might be non-functional and
-         * thus not have responded to SIGTERM. The test script
-         * might also have crashed with SEGV, in which case the
-         * cleanup handlers won't ever run.
-         *
-         * This PR_SET_PDEATHSIG setup will ensure any remaining
-         * QEMU will get terminated with SIGKILL in these cases.
-         */
-        prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
-#endif /* __linux__ */
-#ifdef __FreeBSD__
-        int sig = SIGKILL;
-        procctl(P_PID, getpid(), PROC_PDEATHSIG_CTL, &sig);
-#endif /* __FreeBSD__ */
         execlp("/bin/sh", "sh", "-c", command->str, NULL);
         exit(1);
     }
@@ -482,12 +465,15 @@ gchar *qtest_qemu_args(const char *extra_args)
                       "-display none "
                       "-audio none "
                       "%s"
+                      "%s"
                       " -accel qtest",
 
                       tracearg,
                       socket_path,
                       getenv("QTEST_LOG") ? DEV_STDERR : DEV_NULL,
                       qmp_socket_path,
+                      can_exit_with_parent() ?
+                      "-run-with exit-with-parent=on " : "",
                       extra_args ?: "");
 
     return args;