From: Paolo Bonzini <pbonz...@redhat.com>
Don't overwrite / leak previously set errors.
Make traversal cope with missing mandatory sub-structs.
Don't try to end a container that could not be started.
v1->v2:
- unchanged
v2->v3:
- instead of examining, assert that we never overwrite errors with
error_set()
- allow visitors to set a NULL struct pointer successfully, so traversal
of incomplete objects can continue
- check for a NULL "obj" before accessing "(*obj)->has_XXX" (this is not a
typo, "obj != NULL" implies "*obj != NULL" here)
- fix start_struct / end_struct balance for unions as well
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com>
---
docs/qapi-code-gen.txt | 2 +
error.c | 3 +-
error.h | 2 +-
qapi/qapi-visit-core.c | 10 ++-
scripts/qapi-visit.py | 150 +++++++++++++++++++++++++---------------
tests/test-qmp-input-visitor.c | 24 ++++---
6 files changed, 121 insertions(+), 70 deletions(-)
diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index ad11767..cccb11e 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -220,6 +220,8 @@ Example:
#endif
mdroth@illuin:~/w/qemu2.git$
+(The actual structure of the visit_type_* functions is a bit more complex
+in order to propagate errors correctly and avoid leaking memory).
=== scripts/qapi-commands.py ===
diff --git a/error.c b/error.c
index a52b771..58f55a0 100644
--- a/error.c
+++ b/error.c
@@ -32,6 +32,7 @@ void error_set(Error **errp, const char *fmt, ...)
if (errp == NULL) {
return;
}
+ assert(*errp == NULL);
err = g_malloc0(sizeof(*err));
@@ -132,7 +133,7 @@ bool error_is_type(Error *err, const char *fmt)
void error_propagate(Error **dst_err, Error *local_err)
{
- if (dst_err) {
+ if (dst_err && !*dst_err) {
*dst_err = local_err;
} else if (local_err) {
error_free(local_err);
diff --git a/error.h b/error.h
index 45ff6c1..3d9d96d 100644
--- a/error.h
+++ b/error.h
@@ -57,7 +57,7 @@ void error_set_field(Error *err, const char *field, const
char *value);
/**
* Propagate an error to an indirect pointer to an error. This function will
* always transfer ownership of the error reference and handles the case where
- * dst_err is NULL correctly.
+ * dst_err is NULL correctly. Errors after the first are discarded.
*/
void error_propagate(Error **dst_err, Error *local_err);
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index 705eca9..d41595e 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -39,9 +39,8 @@ void visit_start_struct(Visitor *v, void **obj, const char
*kind,
void visit_end_struct(Visitor *v, Error **errp)
{
- if (!error_is_set(errp)) {
- v->end_struct(v, errp);
- }
+ assert(!error_is_set(errp));
+ v->end_struct(v, errp);
}
void visit_start_list(Visitor *v, const char *name, Error **errp)
@@ -62,9 +61,8 @@ GenericList *visit_next_list(Visitor *v, GenericList **list,
Error **errp)
void visit_end_list(Visitor *v, Error **errp)
{
- if (!error_is_set(errp)) {
- v->end_list(v, errp);
- }
+ assert(!error_is_set(errp));
+ v->end_list(v, errp);
}
void visit_start_optional(Visitor *v, bool *present, const char *name,
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 8d4e94a..04ef7c4 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -17,32 +17,49 @@ import os
import getopt
import errno
-def generate_visit_struct_body(field_prefix, members):
- ret = ""
+def generate_visit_struct_body(field_prefix, name, members):
+ ret = mcgen('''
+if (!error_is_set(errp)) {
+''')
+ push_indent()
+
if len(field_prefix):
field_prefix = field_prefix + "."
+ ret += mcgen('''
+Error **errp = &err; /* from outer scope */
+Error *err = NULL;
+visit_start_struct(m, NULL, "", "%(name)s", 0, &err);
+''',
+ name=name)
+ else:
+ ret += mcgen('''
+Error *err = NULL;
+visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s), &err);
+''',
+ name=name)
+
+ ret += mcgen('''
+if (!err) {
+ if (!obj || *obj) {
+''')
+
+ push_indent()
+ push_indent()
for argname, argentry, optional, structured in parse_args(members):
if optional:
ret += mcgen('''
-visit_start_optional(m, (obj && *obj) ? &(*obj)->%(c_prefix)shas_%(c_name)s :
NULL, "%(name)s", errp);
-if ((*obj)->%(prefix)shas_%(c_name)s) {
+visit_start_optional(m, obj ? &(*obj)->%(c_prefix)shas_%(c_name)s : NULL,
"%(name)s", &err);
+if (obj && (*obj)->%(prefix)shas_%(c_name)s) {
''',
c_prefix=c_var(field_prefix), prefix=field_prefix,
c_name=c_var(argname), name=argname)
push_indent()
if structured:
- ret += mcgen('''
-visit_start_struct(m, NULL, "", "%(name)s", 0, errp);
-''',
- name=argname)
- ret += generate_visit_struct_body(field_prefix + argname, argentry)
- ret += mcgen('''
-visit_end_struct(m, errp);
-''')
+ ret += generate_visit_struct_body(field_prefix + argname, argname,
argentry)
else:
ret += mcgen('''
-visit_type_%(type)s(m, (obj && *obj) ? &(*obj)->%(c_prefix)s%(c_name)s : NULL,
"%(name)s", errp);
+visit_type_%(type)s(m, obj ? &(*obj)->%(c_prefix)s%(c_name)s : NULL,
"%(name)s", &err);
''',
c_prefix=c_var(field_prefix), prefix=field_prefix,
type=type_name(argentry), c_name=c_var(argname),
@@ -52,7 +69,25 @@ visit_type_%(type)s(m, (obj && *obj) ?
&(*obj)->%(c_prefix)s%(c_name)s : NULL, "
pop_indent()
ret += mcgen('''
}
-visit_end_optional(m, errp);
+visit_end_optional(m, &err);
+''')
+
+ pop_indent()
+ ret += mcgen('''
+
+ error_propagate(errp, err);
+ err = NULL;
+}
+''')
+
+ pop_indent()
+ pop_indent()
+ ret += mcgen('''
+ /* Always call end_struct if start_struct succeeded. */
+ visit_end_struct(m, &err);
+ }
+ error_propagate(errp, err);
+}
''')
return ret
@@ -61,22 +96,14 @@ def generate_visit_struct(name, members):
void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error
**errp)
{
- if (error_is_set(errp)) {
- return;
- }
- visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s),
errp);
- if (obj && !*obj) {
- goto end;
- }
''',
name=name)
+
push_indent()
- ret += generate_visit_struct_body("", members)
+ ret += generate_visit_struct_body("", name, members)
pop_indent()
ret += mcgen('''
-end:
- visit_end_struct(m, errp);
}
''')
return ret
@@ -87,18 +114,23 @@ def generate_visit_list(name, members):
void visit_type_%(name)sList(Visitor *m, %(name)sList ** obj, const char
*name, Error **errp)
{
GenericList *i, **prev = (GenericList **)obj;
+ Error *err = NULL;
- if (error_is_set(errp)) {
- return;
- }
- visit_start_list(m, name, errp);
-
- for (; (i = visit_next_list(m, prev, errp)) != NULL; prev = &i) {
- %(name)sList *native_i = (%(name)sList *)i;
- visit_type_%(name)s(m, &native_i->value, NULL, errp);
+ if (!error_is_set(errp)) {
+ visit_start_list(m, name, &err);
+ if (!err) {
+ for (; (i = visit_next_list(m, prev, &err)) != NULL; prev = &i) {
+ %(name)sList *native_i = (%(name)sList *)i;
+ visit_type_%(name)s(m, &native_i->value, NULL, &err);
+ }
+ error_propagate(errp, err);
+ err = NULL;
+
+ /* Always call end_list if start_list succeeded. */
+ visit_end_list(m, &err);
+ }
+ error_propagate(errp, err);
}
-
- visit_end_list(m, errp);
}
''',
name=name)
@@ -122,27 +154,23 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj,
const char *name, Error **
{
Error *err = NULL;
- if (error_is_set(errp)) {
- return;
- }
- visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s),
&err);
- if (obj && !*obj) {
- goto end;
- }
- visit_type_%(name)sKind(m, &(*obj)->kind, "type", &err);
- if (err) {
- error_propagate(errp, err);
- goto end;
- }
- switch ((*obj)->kind) {
+ if (!error_is_set(errp)) {
+ visit_start_struct(m, (void **)obj, "%(name)s", name,
sizeof(%(name)s), &err);
+ if (!err) {
+ if (!obj || *obj) {
+ visit_type_%(name)sKind(m, &(*obj)->kind, "type", &err);
+ if (!err) {
+ switch ((*obj)->kind) {
''',
name=name)
+ push_indent()
+ push_indent()
for key in members:
ret += mcgen('''
- case %(abbrev)s_KIND_%(enum)s:
- visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", errp);
- break;
+ case %(abbrev)s_KIND_%(enum)s:
+ visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err);
+ break;
''',
abbrev = de_camel_case(name).upper(),
enum = c_fun(de_camel_case(key)).upper(),
@@ -150,11 +178,25 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj,
const char *name, Error **
c_name=c_fun(key))
ret += mcgen('''
- default:
- abort();
+ default:
+ abort();
+ }
+ }
+ error_propagate(errp, err);
+ err = NULL;
+ }
+''')
+ pop_indent()
+ ret += mcgen('''
+ /* Always call end_struct if start_struct succeeded. */
+ visit_end_struct(m, &err);
}
-end:
- visit_end_struct(m, errp);
+ error_propagate(errp, err);
+}
+''')
+
+ pop_indent();
+ ret += mcgen('''
}
''')
diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c
index c30fdc4..8f5a509 100644
--- a/tests/test-qmp-input-visitor.c
+++ b/tests/test-qmp-input-visitor.c
@@ -151,14 +151,22 @@ typedef struct TestStruct
static void visit_type_TestStruct(Visitor *v, TestStruct **obj,
const char *name, Error **errp)
{
- visit_start_struct(v, (void **)obj, "TestStruct", name, sizeof(TestStruct),
- errp);
-
- visit_type_int(v, &(*obj)->integer, "integer", errp);
- visit_type_bool(v, &(*obj)->boolean, "boolean", errp);
- visit_type_str(v, &(*obj)->string, "string", errp);
-
- visit_end_struct(v, errp);
+ Error *err = NULL;
+ if (!error_is_set(errp)) {
+ visit_start_struct(v, (void **)obj, "TestStruct", name,
sizeof(TestStruct),
+ &err);
+ if (!err) {
+ visit_type_int(v, &(*obj)->integer, "integer", &err);
+ visit_type_bool(v, &(*obj)->boolean, "boolean", &err);
+ visit_type_str(v, &(*obj)->string, "string", &err);
+
+ /* Always call end_struct if start_struct succeeded. */
+ error_propagate(errp, err);
+ err = NULL;
+ visit_end_struct(v, &err);
+ }
+ error_propagate(errp, err);
+ }
}
static void test_visitor_in_struct(TestInputVisitorData *data,
--
1.7.10.4
