[Qemu-devel] [PATCH 2/2] qtest: keep list of qtest instances for SIGABRT handler

[Stefan Hajnoczi <stefanha@redhat.com>]

Keep track of active qtest instances so we can kill them when the test
aborts.  This ensures no QEMU processes are left running after test
failure.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/libqtest.c | 47 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/tests/libqtest.c b/tests/libqtest.c
index 2b90e4a..d9e3a33 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -48,6 +48,9 @@ struct QTestState
     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)
@@ -104,7 +107,28 @@ static void kill_qemu(QTestState *s)
 
 static void sigabrt_handler(int signo)
 {
-    kill_qemu(global_qtest);
+    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)
@@ -115,7 +139,6 @@ QTestState *qtest_init(const char *extra_args)
     gchar *qmp_socket_path;
     gchar *command;
     const char *qemu_binary;
-    struct sigaction sigact;
 
     qemu_binary = getenv("QTEST_QEMU_BINARY");
     g_assert(qemu_binary != NULL);
@@ -128,13 +151,12 @@ QTestState *qtest_init(const char *extra_args)
     sock = init_socket(socket_path);
     qmpsock = init_socket(qmp_socket_path);
 
-    /* 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, &s->sigact_old);
+    /* 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) {
@@ -180,7 +202,12 @@ QTestState *qtest_init(const char *extra_args)
 
 void qtest_quit(QTestState *s)
 {
-    sigaction(SIGABRT, &s->sigact_old, NULL);
+    /* 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);
-- 
1.8.5.3