[Qemu-devel] [PATCH 3/3] libqtest: use -chardev exit-on-eof to clean up QEMU

[Stefan Hajnoczi <stefanha@redhat.com>]

When the test case aborts it is important to terminate the QEMU process
so it does not leak.  This was implemented using a SIGABRT handler
function in libqtest that sent SIGTERM to QEMU.

The SIGABRT approach is messy because it requires a global signal
handler but libqtest should support multiple simultaneous instances.

Simplify the code using the new -chardev exit-on-eof option.  QEMU will
automatically exit when our qtest socket closes.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/libqtest.c | 48 +++---------------------------------------------
 1 file changed, 3 insertions(+), 45 deletions(-)

diff --git a/tests/libqtest.c b/tests/libqtest.c
index 98e8f4b..6c3dd27 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -46,12 +46,8 @@ struct QTestState
     bool irq_level[MAX_IRQ];
     GString *rx;
     pid_t qemu_pid;  /* our child QEMU process */
-    struct sigaction sigact_old; /* restored on exit */
 };
 
-static GList *qtest_instances;
-static struct sigaction sigact_old;
-
 #define g_assert_no_errno(ret) do { \
     g_assert_cmpint(ret, !=, -1); \
 } while (0)
@@ -110,32 +106,6 @@ static void kill_qemu(QTestState *s)
     }
 }
 
-static void sigabrt_handler(int signo)
-{
-    GList *elem;
-    for (elem = qtest_instances; elem; elem = elem->next) {
-        kill_qemu(elem->data);
-    }
-}
-
-static void setup_sigabrt_handler(void)
-{
-    struct sigaction sigact;
-
-    /* Catch SIGABRT to clean up on g_assert() failure */
-    sigact = (struct sigaction){
-        .sa_handler = sigabrt_handler,
-        .sa_flags = SA_RESETHAND,
-    };
-    sigemptyset(&sigact.sa_mask);
-    sigaction(SIGABRT, &sigact, &sigact_old);
-}
-
-static void cleanup_sigabrt_handler(void)
-{
-    sigaction(SIGABRT, &sigact_old, NULL);
-}
-
 QTestState *qtest_init(const char *extra_args)
 {
     QTestState *s;
@@ -156,17 +126,12 @@ QTestState *qtest_init(const char *extra_args)
     sock = init_socket(socket_path);
     qmpsock = init_socket(qmp_socket_path);
 
-    /* Only install SIGABRT handler once */
-    if (!qtest_instances) {
-        setup_sigabrt_handler();
-    }
-
-    qtest_instances = g_list_prepend(qtest_instances, s);
-
     s->qemu_pid = fork();
     if (s->qemu_pid == 0) {
         command = g_strdup_printf("exec %s "
-                                  "-qtest unix:%s,nowait "
+                                  "-chardev socket,id=qtestdev,path=%s,nowait,"
+                                  "exit-on-eof "
+                                  "-qtest chardev:qtestdev "
                                   "-qtest-log /dev/null "
                                   "-qmp unix:%s,nowait "
                                   "-machine accel=qtest "
@@ -207,13 +172,6 @@ QTestState *qtest_init(const char *extra_args)
 
 void qtest_quit(QTestState *s)
 {
-    /* Uninstall SIGABRT handler on last instance */
-    if (qtest_instances && !qtest_instances->next) {
-        cleanup_sigabrt_handler();
-    }
-
-    qtest_instances = g_list_remove(qtest_instances, s);
-
     kill_qemu(s);
     close(s->fd);
     close(s->qmp_fd);
-- 
1.9.3