[Qemu-devel] [RFC PATCH] tests: Add a device_add/del HMP test

[Thomas Huth <thuth@redhat.com>]

People tend to forget to mark internal devices with "user_creatable = false
or hotpluggable = false, and these devices can crash QEMU if added via the
HMP monitor. So let's add a test to run through all devices and that tries
to add them blindly (without arguments) to see whether this could crash the
QEMU instance.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 I've marked the patch as RFC since not all of the required device bug
 fixes have been merged yet (so this patch can not be included yet without
 breaking "make check"). It's also sad that "macio-oldworld" currently
 has to be blacklisted - I tried to find a fix for that device,  but I was
 not able to spot the exact problem so far. So help for fixing that device
 is very very welcome! The crash can be reproduced like this:

 $ qemu-system-ppc64 -nographic -S -monitor stdio -serial none
 QEMU 2.10.50 monitor - type 'help' for more information
 (qemu) device_add macio-oldworld,id=x
 (qemu) device_del x
 (qemu) **
 ERROR:qom/object.c:1611:object_get_canonical_path_component:
  assertion failed: (obj->parent != NULL)
 Aborted (core dumped)

 tests/test-hmp.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

diff --git a/tests/test-hmp.c b/tests/test-hmp.c
index 7a38cdc..e8a25c4 100644
--- a/tests/test-hmp.c
+++ b/tests/test-hmp.c
@@ -28,7 +28,6 @@ static const char *hmp_cmds[] = {
     "commit all",
     "cpu-add 1",
     "cpu 0",
-    "device_add ?",
     "device_add usb-mouse,id=mouse1",
     "mouse_button 7",
     "mouse_move 10 10",
@@ -116,6 +115,64 @@ static void test_info_commands(void)
     g_free(info_buf);
 }
 
+/*
+ * People tend to forget to mark internal devices with "user_creatable = false
+ * and these devices can crash QEMU if added via the HMP monitor. So let's run
+ * through all devices and try to add them blindly (without arguments) to see
+ * whether this could crash the QEMU instance.
+ */
+static void test_device_add_commands(void)
+{
+    char *resp, *devices, *devices_buf, *endp;
+
+    devices = devices_buf = hmp("device_add help");
+
+    while (*devices) {
+        /* Ignore header lines etc. */
+        if (strncmp(devices, "name \"", 6)) {
+            devices = strchr(devices, '\n');
+            if (!devices) {
+                break;
+            }
+            devices += 1;
+            continue;
+        }
+        /* Extract the device name, ignore parameters and description */
+        devices += 6;
+        endp = strchr(devices, '"');
+        g_assert(endp != NULL);
+        *endp = '\0';
+        /* Check whether it is blacklisted... */
+        if (g_str_equal("macio-oldworld", devices)) {
+            devices = strchr(endp + 1, '\n');
+            if (!devices) {
+                break;
+            }
+            devices += 1;
+            continue;
+        }
+        /* Now run the device_add + device_del commands */
+        if (verbose) {
+            fprintf(stderr, "\tdevice_add %s,id=%s\n", devices, devices);
+        }
+        resp = hmp("device_add %s,id=%s", devices, devices);
+        g_free(resp);
+        if (verbose) {
+            fprintf(stderr, "\tdevice_del %s\n", devices);
+        }
+        resp = hmp("device_del %s", devices);
+        g_free(resp);
+        /* And move forward to the next line */
+        devices = strchr(endp + 1, '\n');
+        if (!devices) {
+            break;
+        }
+        devices += 1;
+    }
+
+    g_free(devices_buf);
+}
+
 static void test_machine(gconstpointer data)
 {
     const char *machine = data;
@@ -125,6 +182,7 @@ static void test_machine(gconstpointer data)
     qtest_start(args);
 
     test_info_commands();
+    test_device_add_commands();
     test_commands();
 
     qtest_end();
-- 
1.8.3.1