[Qemu-devel] [PATCH] qdev: Don't exit when running into bad -global

[Markus Armbruster <armbru@redhat.com>]

-global lets you set a nice booby-trap for yourself:

    $ qemu-system-x86_64 -nodefaults -S -display none -usb -monitor stdio -global usb-mouse.usb_version=l
    QEMU 2.1.94 monitor - type 'help' for more information
    (qemu) device_add usb-mouse
    Parameter 'usb_version' expects an int64 value or range
    $ echo $?
    1

Not nice.  Until commit 3196270 we even abort()ed.

The same error triggers if you manage to screw up a machine type's
compat_props.  To demonstrate, change HW_COMPAT_2_1's entry to

            .driver   = "usb-mouse",\
            .property = "usb_version",\
            .value    = "1", \

Then run

    $ qemu-system-x86_64 -usb -M pc-i440fx-2.1 -device usb-mouse
    upstream-qemu: -device usb-mouse: Parameter 'usb_version' expects an int64 value or range
    $ echo $?
    1

One of our creatively cruel error messages.

Since this is actually a coding error, we *should* abort() here.
Replace the error by an assertion failure in this case.

But turn the fatal error into a mere warning when the faulty
GlobalProperty comes from the user.  Looks like this:

    $ qemu-system-x86_64 -nodefaults -S -display none -usb -monitor stdio -global usb-mouse.usb_version=l
    QEMU 2.1.94 monitor - type 'help' for more information
    (qemu) device_add usb-mouse
    Warning: global usb-mouse.usb_version=l ignored (Parameter 'usb_version' expects an int64 value or range)
    (qemu)

This is consistent with how we handle similarly unusable -global in
qdev_prop_check_globals().

You could argue that the error should make device_add fail.  Would be
harder, because we're running within TypeInfo's instance_post_init()
method device_post_init(), which can't fail.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/core/qdev-properties.c    | 21 +++++++++------------
 hw/core/qdev.c               |  8 +-------
 include/hw/qdev-properties.h |  4 +---
 3 files changed, 11 insertions(+), 22 deletions(-)

diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index 2e47f70..5a4e4d5 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -990,8 +990,8 @@ int qdev_prop_check_globals(void)
     return ret;
 }
 
-void qdev_prop_set_globals_for_type(DeviceState *dev, const char *typename,
-                                    Error **errp)
+static void qdev_prop_set_globals_for_type(DeviceState *dev,
+                                const char *typename)
 {
     GlobalProperty *prop;
 
@@ -1004,25 +1004,22 @@ void qdev_prop_set_globals_for_type(DeviceState *dev, const char *typename,
         prop->used = true;
         object_property_parse(OBJECT(dev), prop->value, prop->property, &err);
         if (err != NULL) {
-            error_propagate(errp, err);
+            assert(prop->user_provided);
+            error_report("Warning: global %s.%s=%s ignored (%s)",
+                         prop->driver, prop->property, prop->value,
+                         error_get_pretty(err));
+            error_free(err);
             return;
         }
     }
 }
 
-void qdev_prop_set_globals(DeviceState *dev, Error **errp)
+void qdev_prop_set_globals(DeviceState *dev)
 {
     ObjectClass *class = object_get_class(OBJECT(dev));
 
     do {
-        Error *err = NULL;
-
-        qdev_prop_set_globals_for_type(dev, object_class_get_name(class),
-                                       &err);
-        if (err != NULL) {
-            error_propagate(errp, err);
-            return;
-        }
+        qdev_prop_set_globals_for_type(dev, object_class_get_name(class));
         class = object_class_get_parent(class);
     } while (class);
 }
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 901f289..827c084 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -1126,13 +1126,7 @@ static void device_initfn(Object *obj)
 
 static void device_post_init(Object *obj)
 {
-    Error *err = NULL;
-    qdev_prop_set_globals(DEVICE(obj), &err);
-    if (err) {
-        qerror_report_err(err);
-        error_free(err);
-        exit(EXIT_FAILURE);
-    }
+    qdev_prop_set_globals(DEVICE(obj));
 }
 
 /* Unlink device from bus and free the structure.  */
diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
index 070006c..57ee363 100644
--- a/include/hw/qdev-properties.h
+++ b/include/hw/qdev-properties.h
@@ -180,9 +180,7 @@ void qdev_prop_set_ptr(DeviceState *dev, const char *name, void *value);
 void qdev_prop_register_global(GlobalProperty *prop);
 void qdev_prop_register_global_list(GlobalProperty *props);
 int qdev_prop_check_globals(void);
-void qdev_prop_set_globals(DeviceState *dev, Error **errp);
-void qdev_prop_set_globals_for_type(DeviceState *dev, const char *typename,
-                                    Error **errp);
+void qdev_prop_set_globals(DeviceState *dev);
 void error_set_from_qdev_prop_error(Error **errp, int ret, DeviceState *dev,
                                     Property *prop, const char *value);
 
-- 
1.9.3