qdev-monitor-test: add device_add leak test cases

Ensure that the device_add error code path deletes device objects.
Failure to do so not only leaks the objects but can also keep other
objects (like drive or netdev) alive due to qdev properties holding
references.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

tests/Makefile

@@ -69,6 +69,7 @@ check-qtest-i386-y += tests/i440fx-test$(EXESUF)
 check-qtest-i386-y += tests/fw_cfg-test$(EXESUF)
 check-qtest-i386-y += tests/qom-test$(EXESUF)
 check-qtest-i386-y += tests/blockdev-test$(EXESUF)
+check-qtest-i386-y += tests/qdev-monitor-test$(EXESUF)
 check-qtest-x86_64-y = $(check-qtest-i386-y)
 gcov-files-i386-y += i386-softmmu/hw/mc146818rtc.c
 gcov-files-x86_64-y = $(subst i386-softmmu/,x86_64-softmmu/,$(gcov-files-i386-y))
@@ -202,6 +203,7 @@ tests/i440fx-test$(EXESUF): tests/i440fx-test.o $(libqos-pc-obj-y)
 tests/fw_cfg-test$(EXESUF): tests/fw_cfg-test.o $(libqos-pc-obj-y)
 tests/qom-test$(EXESUF): tests/qom-test.o
 tests/blockdev-test$(EXESUF): tests/blockdev-test.o $(libqos-pc-obj-y)
+tests/qdev-monitor-test$(EXESUF): tests/qdev-monitor-test.o $(libqos-pc-obj-y)
 tests/qemu-iotests/socket_scm_helper$(EXESUF): tests/qemu-iotests/socket_scm_helper.o
 
 # QTest rules

tests/qdev-monitor-test.c

+/*
+ * qdev-monitor.c test cases
+ *
+ * Copyright (C) 2013 Red Hat Inc.
+ *
+ * Authors:
+ *  Stefan Hajnoczi <stefanha@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#include <string.h>
+#include <glib.h>
+#include "libqtest.h"
+#include "qapi/qmp/qjson.h"
+
+static void test_device_add(void)
+{
+    QDict *response;
+    QDict *error;
+
+    qtest_start("-drive if=none,id=drive0");
+
+    /* Make device_add fail.  If this leaks the virtio-blk-pci device then a
+     * reference to drive0 will also be held (via qdev properties).
+     */
+    response = qmp("{\"execute\": \"device_add\","
+                   " \"arguments\": {"
+                   "   \"driver\": \"virtio-blk-pci\","
+                   "   \"drive\": \"drive0\""
+                   "}}");
+    g_assert(response);
+    error = qdict_get_qdict(response, "error");
+    g_assert(!strcmp(qdict_get_try_str(error, "class") ?: "",
+                     "GenericError"));
+    g_assert(!strcmp(qdict_get_try_str(error, "desc") ?: "",
+                     "Device initialization failed."));
+    QDECREF(response);
+
+    /* Delete the drive */
+    response = qmp("{\"execute\": \"human-monitor-command\","
+                   " \"arguments\": {"
+                   "   \"command-line\": \"drive_del drive0\""
+                   "}}");
+    g_assert(response);
+    g_assert(!strcmp(qdict_get_try_str(response, "return") ?: "(null)", ""));
+    QDECREF(response);
+
+    /* Try to re-add the drive.  This fails with duplicate IDs if a leaked
+     * virtio-blk-pci exists that holds a reference to the old drive0.
+     */
+    response = qmp("{\"execute\": \"human-monitor-command\","
+                   " \"arguments\": {"
+                   "   \"command-line\": \"drive_add pci-addr=auto if=none,id=drive0\""
+                   "}}");
+    g_assert(response);
+    g_assert(!strcmp(qdict_get_try_str(response, "return") ?: "",
+                     "OK\r\n"));
+    QDECREF(response);
+
+    qtest_end();
+}
+
+int main(int argc, char **argv)
+{
+    const char *arch = qtest_get_arch();
+
+    /* Check architecture */
+    if (strcmp(arch, "i386") && strcmp(arch, "x86_64")) {
+        g_test_message("Skipping test for non-x86\n");
+        return 0;
+    }
+
+    /* Run the tests */
+    g_test_init(&argc, &argv, NULL);
+
+    qtest_add_func("/qmp/device_add", test_device_add);
+
+    return g_test_run();
+}