As mentioned in previous patches, we want to call visit_end_struct()
functions unconditionally, so that visitors can release resources
tied up since the matching visit_start_struct() without also having
to worry about error priority if more than one error occurs.
Even though error_propagate() can be safely used to ignore a second
error during cleanup caused by a first error, it is simpler if the
cleanup cannot set an error, and we instead split the task of
checking that an input visitor has no unvisited input as a new
function visit_check_struct(), called only if all prior steps are
successful.
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
v6: new patch, revised version of RFC based on discussion of v5 7/46
---
hmp.c | 8 +++-----
hw/ppc/spapr_drc.c | 3 ++-
hw/virtio/virtio-balloon.c | 12 ++++++------
include/qapi/visitor-impl.h | 4 +++-
include/qapi/visitor.h | 12 ++++++++++--
qapi/opts-visitor.c | 17 +++++++++++++++--
qapi/qapi-dealloc-visitor.c | 2 +-
qapi/qapi-visit-core.c | 11 +++++++++--
qapi/qmp-input-visitor.c | 34 +++++++++++++++++++---------------
qapi/qmp-output-visitor.c | 2 +-
qom/object.c | 5 ++---
scripts/qapi-event.py | 3 ++-
scripts/qapi-visit.py | 9 ++++-----
vl.c | 9 ++++-----
14 files changed, 81 insertions(+), 50 deletions(-)
diff --git a/hmp.c b/hmp.c
index ec1d682..b09f78b 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1663,7 +1663,6 @@ void hmp_netdev_del(Monitor *mon, const QDict *qdict)
void hmp_object_add(Monitor *mon, const QDict *qdict)
{
Error *err = NULL;
- Error *err_end = NULL;
QemuOpts *opts;
char *type = NULL;
char *id = NULL;
@@ -1696,13 +1695,12 @@ void hmp_object_add(Monitor *mon, const QDict *qdict)
if (err) {
goto out_end;
}
-
+ visit_check_struct(v, &err);
out_end:
- visit_end_struct(v, &err_end);
- if (!err && !err_end) {
+ visit_end_struct(v);
+ if (!err) {
object_add(type, id, pdict, v, &err);
}
- error_propagate(&err, err_end);
out_clean:
opts_visitor_cleanup(ov);
diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index 03a1879..5ff270f 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -281,7 +281,8 @@ static void prop_get_fdt(Object *obj, Visitor *v, void
*opaque,
case FDT_END_NODE:
/* shouldn't ever see an FDT_END_NODE before FDT_BEGIN_NODE */
g_assert(fdt_depth > 0);
- visit_end_struct(v, &error_abort);
+ visit_check_struct(v, &error_abort);
+ visit_end_struct(v);
fdt_depth--;
break;
case FDT_PROP: {
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 1ce987a..531913b 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -136,15 +136,15 @@ static void balloon_stats_get_all(Object *obj, struct
Visitor *v,
goto out_nested;
}
}
+ visit_check_struct(v, &err);
out_nested:
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, &err);
+ visit_end_struct(v);
+ if (!err) {
+ visit_check_struct(v, &err);
+ }
out_end:
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, &err);
+ visit_end_struct(v);
out:
error_propagate(errp, err);
}
diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index 018f419..5350bdf 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -28,8 +28,10 @@ struct Visitor
* currently visit structs). */
void (*start_struct)(Visitor *v, void **obj, const char *kind,
const char *name, size_t size, Error **errp);
+ /* May be NULL; most useful for input visitors. */
+ void (*check_struct)(Visitor *v, Error **errp);
/* Must be provided if start_struct is present. */
- void (*end_struct)(Visitor *v, Error **errp);
+ void (*end_struct)(Visitor *v);
/* May be NULL; most useful for input visitors. */
void (*start_implicit_struct)(Visitor *v, void **obj, size_t size,
diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index cc1ff6d..f9ea325 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -57,11 +57,19 @@ typedef struct GenericList
void visit_start_struct(Visitor *v, void **obj, const char *kind,
const char *name, size_t size, Error **errp);
/**
+ * Prepare for completing a struct visit.
+ * Should be called prior to visit_end_struct() if all other intermediate
+ * visit steps were successful, to allow the caller one last chance to
+ * report errors such as remaining data that was not consumed by the visit.
+ */
+void visit_check_struct(Visitor *v, Error **errp);
+/**
* Complete a struct visit started earlier.
* Must be called after any successful use of visit_start_struct(),
- * even if intermediate processing was skipped due to errors.
+ * even if intermediate processing was skipped due to errors, to allow
+ * the backend to release any resources.
*/
-void visit_end_struct(Visitor *v, Error **errp);
+void visit_end_struct(Visitor *v);
/**
* Prepare to visit an implicit struct.
diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
index 46dd9fe..db5fc1a 100644
--- a/qapi/opts-visitor.c
+++ b/qapi/opts-visitor.c
@@ -151,13 +151,13 @@ opts_start_struct(Visitor *v, void **obj, const char
*kind,
static void
-opts_end_struct(Visitor *v, Error **errp)
+opts_check_struct(Visitor *v, Error **errp)
{
OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
GHashTableIter iter;
GQueue *any;
- if (--ov->depth > 0) {
+ if (ov->depth > 0) {
return;
}
@@ -169,6 +169,18 @@ opts_end_struct(Visitor *v, Error **errp)
first = g_queue_peek_head(any);
error_setg(errp, QERR_INVALID_PARAMETER, first->name);
}
+}
+
+
+static void
+opts_end_struct(Visitor *v)
+{
+ OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+
+ if (--ov->depth > 0) {
+ return;
+ }
+
g_hash_table_destroy(ov->unprocessed_opts);
ov->unprocessed_opts = NULL;
if (ov->fake_id_opt) {
@@ -500,6 +512,7 @@ opts_visitor_new(const QemuOpts *opts)
ov = g_malloc0(sizeof *ov);
ov->visitor.start_struct = &opts_start_struct;
+ ov->visitor.check_struct = &opts_check_struct;
ov->visitor.end_struct = &opts_end_struct;
ov->visitor.start_list = &opts_start_list;
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
index 8b489a4..14dc7c3 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -67,7 +67,7 @@ static void qapi_dealloc_start_struct(Visitor *v, void **obj,
const char *kind,
qapi_dealloc_push(qov, obj);
}
-static void qapi_dealloc_end_struct(Visitor *v, Error **errp)
+static void qapi_dealloc_end_struct(Visitor *v)
{
QapiDeallocVisitor *qov = to_qov(v);
void **obj = qapi_dealloc_pop(qov);
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index a193a04..00f446e 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -23,9 +23,16 @@ void visit_start_struct(Visitor *v, void **obj, const char
*kind,
v->start_struct(v, obj, kind, name, size, errp);
}
-void visit_end_struct(Visitor *v, Error **errp)
+void visit_check_struct(Visitor *v, Error **errp)
{
- v->end_struct(v, errp);
+ if (v->check_struct) {
+ v->check_struct(v, errp);
+ }
+}
+
+void visit_end_struct(Visitor *v)
+{
+ v->end_struct(v);
}
void visit_start_implicit_struct(Visitor *v, void **obj, size_t size,
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 9dbe025..0270d25 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -89,8 +89,10 @@ static void qmp_input_push(QmpInputVisitor *qiv, QObject
*obj, Error **errp)
}
-static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
+static void qmp_input_check_struct(Visitor *v, Error **errp)
{
+ QmpInputVisitor *qiv = to_qiv(v);
+
assert(qiv->nb_stack > 0);
if (qiv->strict) {
@@ -103,6 +105,19 @@ static void qmp_input_pop(QmpInputVisitor *qiv, Error
**errp)
if (g_hash_table_iter_next(&iter, (void **)&key, NULL)) {
error_setg(errp, QERR_QMP_EXTRA_MEMBER, key);
}
+ }
+ }
+}
+
+static void qmp_input_pop(Visitor *v)
+{
+ QmpInputVisitor *qiv = to_qiv(v);
+
+ assert(qiv->nb_stack > 0);
+
+ if (qiv->strict) {
+ GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h;
+ if (top_ht) {
g_hash_table_unref(top_ht);
}
}
@@ -134,12 +149,6 @@ static void qmp_input_start_struct(Visitor *v, void **obj,
const char *kind,
}
}
-static void qmp_input_end_struct(Visitor *v, Error **errp)
-{
- QmpInputVisitor *qiv = to_qiv(v);
-
- qmp_input_pop(qiv, errp);
-}
static void qmp_input_start_implicit_struct(Visitor *v, void **obj,
size_t size, Error **errp)
@@ -193,12 +202,6 @@ static GenericList *qmp_input_next_list(Visitor *v,
GenericList **list,
return entry;
}
-static void qmp_input_end_list(Visitor *v)
-{
- QmpInputVisitor *qiv = to_qiv(v);
-
- qmp_input_pop(qiv, &error_abort);
-}
static void qmp_input_get_next_type(Visitor *v, QType *type, bool promote_int,
const char *name, Error **errp)
@@ -341,11 +344,12 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
v = g_malloc0(sizeof(*v));
v->visitor.start_struct = qmp_input_start_struct;
- v->visitor.end_struct = qmp_input_end_struct;
+ v->visitor.check_struct = qmp_input_check_struct;
+ v->visitor.end_struct = qmp_input_pop;
v->visitor.start_implicit_struct = qmp_input_start_implicit_struct;
v->visitor.start_list = qmp_input_start_list;
v->visitor.next_list = qmp_input_next_list;
- v->visitor.end_list = qmp_input_end_list;
+ v->visitor.end_list = qmp_input_pop;
v->visitor.type_enum = input_type_enum;
v->visitor.type_int64 = qmp_input_type_int64;
v->visitor.type_uint64 = qmp_input_type_uint64;
diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c
index 8035649..af1e01b 100644
--- a/qapi/qmp-output-visitor.c
+++ b/qapi/qmp-output-visitor.c
@@ -122,7 +122,7 @@ static void qmp_output_start_struct(Visitor *v, void **obj,
const char *kind,
qmp_output_push(qov, dict);
}
-static void qmp_output_end_struct(Visitor *v, Error **errp)
+static void qmp_output_end_struct(Visitor *v)
{
QmpOutputVisitor *qov = to_qov(v);
qmp_output_pop(qov);
diff --git a/qom/object.c b/qom/object.c
index d751569..3d5c9d7 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1904,10 +1904,9 @@ static void property_get_tm(Object *obj, Visitor *v,
void *opaque,
if (err) {
goto out_end;
}
+ visit_check_struct(v, &err);
out_end:
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, errp);
+ visit_end_struct(v);
out:
error_propagate(errp, err);
diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py
index 7ee74a5..68d59e1 100644
--- a/scripts/qapi-event.py
+++ b/scripts/qapi-event.py
@@ -74,8 +74,9 @@ def gen_event_send(name, arg_type):
ret += gen_visit_fields(arg_type.members, need_cast=True,
label='out_obj')
ret += mcgen('''
+ visit_check_struct(v, &err);
out_obj:
- visit_end_struct(v, &err);
+ visit_end_struct(v);
if (err) {
goto out;
}
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 43233d6..c28208e 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -255,8 +255,7 @@ void visit_type_%(c_name)s(Visitor *v, %(c_name)s **obj,
const char *name, Error
visit_type_%(c_name)s_fields(v, %(cast)sobj, &err);
''',
c_name=type_name, cast=cast)
- if variants:
- ret += gen_err_check(label='out_obj')
+ ret += gen_err_check(label='out_obj')
if variants:
ret += mcgen('''
@@ -293,12 +292,12 @@ void visit_type_%(c_name)s(Visitor *v, %(c_name)s **obj,
const char *name, Error
abort();
}
''')
+ ret += gen_err_check(label='out_obj')
ret += mcgen('''
+ visit_check_struct(v, &err);
out_obj:
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, &err);
+ visit_end_struct(v);
out:
error_propagate(errp, err);
}
diff --git a/vl.c b/vl.c
index 4e69815..32e4300 100644
--- a/vl.c
+++ b/vl.c
@@ -2828,7 +2828,6 @@ static bool object_create_delayed(const char *type)
static int object_create(void *opaque, QemuOpts *opts, Error **errp)
{
Error *err = NULL;
- Error *err_end = NULL;
char *type = NULL;
char *id = NULL;
OptsVisitor *ov;
@@ -2848,7 +2847,7 @@ static int object_create(void *opaque, QemuOpts *opts,
Error **errp)
qdict_del(pdict, "qom-type");
visit_type_str(v, &type, "qom-type", &err);
if (err) {
- goto out;
+ goto out_end;
}
if (!type_predicate(type)) {
goto out_end;
@@ -2859,10 +2858,10 @@ static int object_create(void *opaque, QemuOpts *opts,
Error **errp)
if (err) {
goto out_end;
}
-
+ visit_check_struct(v, &err);
out_end:
- visit_end_struct(v, &err_end);
- if (!err && !err_end) {
+ visit_end_struct(v);
+ if (!err) {
object_add(type, id, pdict, v, &err);
}
--
2.4.3
