[PATCH V1 05/11] tests/qtest: qtest_init_after_exec

[Steve Sistare <steven.sistare@oracle.com>]

Define a function to create a QTestState object representing the state
of QEMU after old QEMU exec's new QEMU.  This is needed for testing
the cpr-exec migration mode.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 tests/qtest/libqtest.h |  8 ++++++++
 tests/qtest/libqtest.c | 19 +++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/tests/qtest/libqtest.h b/tests/qtest/libqtest.h
index a164f58..ce6b9b0 100644
--- a/tests/qtest/libqtest.h
+++ b/tests/qtest/libqtest.h
@@ -57,6 +57,14 @@ QTestState *qtest_vinitf(const char *fmt, va_list ap) G_GNUC_PRINTF(1, 0);
 const char *qtest_qemu_binary(const char *var);
 
 /**
+ * qtest_init_after_exec:
+ * @from: the previous QEMU state
+ *
+ * Return a test state representing new QEMU after @from exec's it.
+ */
+QTestState *qtest_init_after_exec(QTestState *from);
+
+/**
  * qtest_qemu_args:
  * @extra_args: Other arguments to pass to QEMU.
  *
diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index d97144e..3522d75 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -615,6 +615,25 @@ QTestState *qtest_init_ext(const char *var, const char *extra_args,
     return s;
 }
 
+static QTestState *qtest_attach_qemu(const char *qemu_bin,
+                                     const char *extra_args,
+                                     void *opaque)
+{
+    int pid = *(int *)opaque;
+    return qtest_create_test_state(pid);
+}
+
+QTestState *qtest_init_after_exec(QTestState *from)
+{
+    void *opaque = (void *)&from->qemu_pid;
+    QTestState *s;
+
+    s = qtest_init_internal(NULL, NULL, true, qtest_attach_qemu, opaque);
+    from->qemu_pid = -1;
+    qtest_qmp_handshake(s, NULL);
+    return s;
+}
+
 QTestState *qtest_init(const char *extra_args)
 {
     return qtest_init_ext(NULL, extra_args, NULL, true);
-- 
1.8.3.1