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 <arm...@redhat.com>
---
backends/rng.c | 11 +++++++----
backends/tpm.c | 11 +++++++----
hw/core/qdev-properties.c | 11 +++++++----
hw/misc/tmp105.c | 6 ++++--
hw/virtio/virtio-balloon.c | 6 ++++--
target-i386/cpu.c | 24 ++++++++++++++++--------
6 files changed, 45 insertions(+), 24 deletions(-)
diff --git a/backends/rng.c b/backends/rng.c
index 8b8d5a4..0f2fc11 100644
--- a/backends/rng.c
+++ b/backends/rng.c
@@ -50,6 +50,7 @@ static void rng_backend_prop_set_opened(Object *obj, bool
value, Error **errp)
{
RngBackend *s = RNG_BACKEND(obj);
RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
+ Error *local_err = NULL;
if (value == s->opened) {
return;
@@ -61,12 +62,14 @@ static void rng_backend_prop_set_opened(Object *obj, bool
value, Error **errp)
}
if (k->opened) {
- k->opened(s, errp);
+ k->opened(s, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
}
- if (!error_is_set(errp)) {
- s->opened = value;
- }
+ s->opened = true;
}
static void rng_backend_init(Object *obj)
diff --git a/backends/tpm.c b/backends/tpm.c
index b735801..01860c4 100644
--- a/backends/tpm.c
+++ b/backends/tpm.c
@@ -112,6 +112,7 @@ static void tpm_backend_prop_set_opened(Object *obj, bool
value, Error **errp)
{
TPMBackend *s = TPM_BACKEND(obj);
TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
+ Error *local_err = NULL;
if (value == s->opened) {
return;
@@ -123,12 +124,14 @@ static void tpm_backend_prop_set_opened(Object *obj, bool
value, Error **errp)
}
if (k->opened) {
- k->opened(s, errp);
+ k->opened(s, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
}
- if (!error_is_set(errp)) {
- s->opened = value;
- }
+ s->opened = true;
}
static void tpm_backend_instance_init(Object *obj)
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index c67acf5..5c08611 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -746,6 +746,7 @@ static void set_prop_arraylen(Object *obj, Visitor *v, void
*opaque,
* array-length field in the device struct, we have to create the
* array itself and dynamically add the corresponding properties.
*/
+ Error *local_err = NULL;
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
uint32_t *alenptr = qdev_get_prop_ptr(dev, prop);
@@ -763,8 +764,9 @@ static void set_prop_arraylen(Object *obj, Visitor *v, void
*opaque,
name);
return;
}
- visit_type_uint32(v, alenptr, name, errp);
- if (error_is_set(errp)) {
+ visit_type_uint32(v, alenptr, name, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
if (!*alenptr) {
@@ -801,8 +803,9 @@ static void set_prop_arraylen(Object *obj, Visitor *v, void
*opaque,
arrayprop->prop.info->get,
arrayprop->prop.info->set,
array_element_release,
- arrayprop, errp);
- if (error_is_set(errp)) {
+ arrayprop, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
}
diff --git a/hw/misc/tmp105.c b/hw/misc/tmp105.c
index 63aa3d6..e11657d 100644
--- a/hw/misc/tmp105.c
+++ b/hw/misc/tmp105.c
@@ -67,11 +67,13 @@ static void tmp105_get_temperature(Object *obj, Visitor *v,
void *opaque,
static void tmp105_set_temperature(Object *obj, Visitor *v, void *opaque,
const char *name, Error **errp)
{
+ Error *local_err = NULL;
TMP105State *s = TMP105(obj);
int64_t temp;
- visit_type_int(v, &temp, name, errp);
- if (error_is_set(errp)) {
+ visit_type_int(v, &temp, name, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
if (temp >= 128000 || temp < -128000) {
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index a470a0b..51f02eb 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -141,11 +141,13 @@ static void balloon_stats_set_poll_interval(Object *obj,
struct Visitor *v,
void *opaque, const char *name,
Error **errp)
{
+ Error *local_err = NULL;
VirtIOBalloon *s = opaque;
int64_t value;
- visit_type_int(v, &value, name, errp);
- if (error_is_set(errp)) {
+ visit_type_int(v, &value, name, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 8fd1497..73954a7 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1296,14 +1296,16 @@ static void x86_cpuid_version_get_family(Object *obj,
Visitor *v, void *opaque,
static void x86_cpuid_version_set_family(Object *obj, Visitor *v, void *opaque,
const char *name, Error **errp)
{
+ Error *local_err = NULL;
X86CPU *cpu = X86_CPU(obj);
CPUX86State *env = &cpu->env;
const int64_t min = 0;
const int64_t max = 0xff + 0xf;
int64_t value;
- visit_type_int(v, &value, name, errp);
- if (error_is_set(errp)) {
+ visit_type_int(v, &value, name, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
if (value < min || value > max) {
@@ -1335,14 +1337,16 @@ static void x86_cpuid_version_get_model(Object *obj,
Visitor *v, void *opaque,
static void x86_cpuid_version_set_model(Object *obj, Visitor *v, void *opaque,
const char *name, Error **errp)
{
+ Error *local_err = NULL;
X86CPU *cpu = X86_CPU(obj);
CPUX86State *env = &cpu->env;
const int64_t min = 0;
const int64_t max = 0xff;
int64_t value;
- visit_type_int(v, &value, name, errp);
- if (error_is_set(errp)) {
+ visit_type_int(v, &value, name, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
if (value < min || value > max) {
@@ -1371,14 +1375,16 @@ static void x86_cpuid_version_set_stepping(Object *obj,
Visitor *v,
void *opaque, const char *name,
Error **errp)
{
+ Error *local_err = NULL;
X86CPU *cpu = X86_CPU(obj);
CPUX86State *env = &cpu->env;
const int64_t min = 0;
const int64_t max = 0xf;
int64_t value;
- visit_type_int(v, &value, name, errp);
- if (error_is_set(errp)) {
+ visit_type_int(v, &value, name, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
if (value < min || value > max) {
@@ -1508,13 +1514,15 @@ static void x86_cpuid_get_tsc_freq(Object *obj, Visitor
*v, void *opaque,
static void x86_cpuid_set_tsc_freq(Object *obj, Visitor *v, void *opaque,
const char *name, Error **errp)
{
+ Error *local_err = NULL;
X86CPU *cpu = X86_CPU(obj);
const int64_t min = 0;
const int64_t max = INT64_MAX;
int64_t value;
- visit_type_int(v, &value, name, errp);
- if (error_is_set(errp)) {
+ visit_type_int(v, &value, name, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
return;
}
if (value < min || value > max) {
--
1.8.1.4
