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65cd9064e1
Using error_is_set(ERRP) to find out whether a function failed is
either wrong, fragile, or unnecessarily opaque. It's wrong when ERRP
may be null, because errors go undetected when it is. It's fragile
when proving ERRP non-null involves a non-local argument. Else, it's
unnecessarily opaque (see commit 84d18f0).
I guess the error_is_set(errp) in the ObjectProperty set() methods are
merely fragile right now, because I can't find a call chain that
passes a null errp argument.
Make the code more robust and more obviously correct: receive the
error in a local variable, then propagate it through the parameter.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
110 lines
2.5 KiB
C
110 lines
2.5 KiB
C
/*
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* QEMU Random Number Generator Backend
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*
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* Copyright IBM, Corp. 2012
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "sysemu/rng.h"
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#include "qapi/qmp/qerror.h"
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#include "qom/object_interfaces.h"
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void rng_backend_request_entropy(RngBackend *s, size_t size,
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EntropyReceiveFunc *receive_entropy,
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void *opaque)
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{
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RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
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if (k->request_entropy) {
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k->request_entropy(s, size, receive_entropy, opaque);
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}
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}
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void rng_backend_cancel_requests(RngBackend *s)
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{
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RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
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if (k->cancel_requests) {
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k->cancel_requests(s);
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}
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}
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static bool rng_backend_prop_get_opened(Object *obj, Error **errp)
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{
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RngBackend *s = RNG_BACKEND(obj);
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return s->opened;
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}
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static void rng_backend_complete(UserCreatable *uc, Error **errp)
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{
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object_property_set_bool(OBJECT(uc), true, "opened", errp);
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}
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static void rng_backend_prop_set_opened(Object *obj, bool value, Error **errp)
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{
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RngBackend *s = RNG_BACKEND(obj);
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RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
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Error *local_err = NULL;
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if (value == s->opened) {
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return;
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}
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if (!value && s->opened) {
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error_set(errp, QERR_PERMISSION_DENIED);
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return;
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}
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if (k->opened) {
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k->opened(s, &local_err);
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if (local_err) {
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error_propagate(errp, local_err);
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return;
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}
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}
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s->opened = true;
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}
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static void rng_backend_init(Object *obj)
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{
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object_property_add_bool(obj, "opened",
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rng_backend_prop_get_opened,
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rng_backend_prop_set_opened,
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NULL);
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}
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static void rng_backend_class_init(ObjectClass *oc, void *data)
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{
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UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
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ucc->complete = rng_backend_complete;
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}
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static const TypeInfo rng_backend_info = {
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.name = TYPE_RNG_BACKEND,
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.parent = TYPE_OBJECT,
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.instance_size = sizeof(RngBackend),
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.instance_init = rng_backend_init,
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.class_size = sizeof(RngBackendClass),
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.class_init = rng_backend_class_init,
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.abstract = true,
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.interfaces = (InterfaceInfo[]) {
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{ TYPE_USER_CREATABLE },
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{ }
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}
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};
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static void register_types(void)
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{
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type_register_static(&rng_backend_info);
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}
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type_init(register_types);
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