mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
23b0d7dfe5
qemu/tests/qapi-schema/qapi-schema-test.out
Eric Blake 0426d53c65 qapi: Simplify visiting of alternate types 
Previously, working with alternates required two lookup arrays
and some indirection: for type Foo, we created Foo_qtypes[]
which maps each qtype to a value of the generated FooKind enum,
then look up that value in FooKind_lookup[] like we do for other
union types.

This has a couple of subtle bugs.  First, the generator was
creating a call with a parameter '(int *) &(*obj)->type' where
type is an enum type; this is unsafe if the compiler chooses
to store the enum type in a different size than int, where
assigning through the wrong size pointer can corrupt data or
cause a SIGBUS.

Related bug, not not fixed in this patch: qapi-visit.py's
gen_visit_enum() generates a cast of its enum * argument to
int *. Marked FIXME.

Second, since the values of the FooKind enum start at zero, all
entries of the Foo_qtypes[] array that were not explicitly
initialized will map to the same branch of the union as the
first member of the alternate, rather than triggering a desired
failure in visit_get_next_type().  Fortunately, the bug seldom
bites; the very next thing the input visitor does is try to
parse the incoming JSON with the wrong parser, which normally
fails; the output visitor is not used with a C struct in that
state, and the dealloc visitor has nothing to clean up (so
there is no leak).

However, the second bug IS observable in one case: parsing an
integer causes unusual behavior in an alternate that contains
at least a 'number' member but no 'int' member, because the
'number' parser accepts QTYPE_QINT in addition to the expected
QTYPE_QFLOAT (that is, since 'int' is not a member, the type
QTYPE_QINT accidentally maps to FooKind 0; if this enum value
is the 'number' branch the integer parses successfully, but if
the 'number' branch is not first, some other branch tries to
parse the integer and rejects it).  A later patch will worry
about fixing alternates to always parse all inputs that a
non-alternate 'number' would accept, for now this is still
marked FIXME in the updated test-qmp-input-visitor.c, to
merely point out that new undesired behavior of 'ans' matches
the existing undesired behavior of 'asn'.

This patch fixes the default-initialization bug by deleting the
indirection, and modifying get_next_type() to directly assign a
QTypeCode parameter.  This in turn fixes the type-casting bug,
as we are no longer casting a pointer to enum to a questionable
size. There is no longer a need to generate an implicit FooKind
enum associated with the alternate type (since the QMP wire
format never uses the stringized counterparts of the C union
member names).  Since the updated visit_get_next_type() does not
know which qtypes are expected, the generated visitor is
modified to generate an error statement if an unexpected type is
encountered.

Callers now have to know the QTYPE_* mapping when looking at the
discriminator; but so far, only the testsuite was even using the
C struct of an alternate types.  I considered the possibility of
keeping the internal enum FooKind, but initialized differently
than most generated arrays, as in:
  typedef enum FooKind {
      FOO_KIND_A = QTYPE_QDICT,
      FOO_KIND_B = QTYPE_QINT,
  } FooKind;
to create nicer aliases for knowing when to use foo->a or foo->b
when inspecting foo->type; but it turned out to add too much
complexity, especially without a client.

There is a user-visible side effect to this change, but I
consider it to be an improvement. Previously,
the invalid QMP command:
  {"execute":"blockdev-add", "arguments":{"options":
    {"driver":"raw", "id":"a", "file":true}}}
failed with:
  {"error": {"class": "GenericError",
    "desc": "Invalid parameter type for 'file', expected: QDict"}}
(visit_get_next_type() succeeded, and the error comes from the
visit_type_BlockdevOptions() expecting {}; there is no mention of
the fact that a string would also work).  Now it fails with:
  {"error": {"class": "GenericError",
    "desc": "Invalid parameter type for 'file', expected: BlockdevRef"}}
(the error when the next type doesn't match any expected types for
the overall alternate).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1449033659-25497-5-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17 08:21:28 +01:00

205 lines
6.8 KiB
Plaintext
Raw Blame History

object :empty
object :obj-EVENT_C-arg
member a: int optional=True
member b: UserDefOne optional=True
member c: str optional=False
object :obj-EVENT_D-arg
member a: EventStructOne optional=False
member b: str optional=False
member c: str optional=True
member enum3: EnumOne optional=True
object :obj-__org.qemu_x-command-arg
member a: __org.qemu_x-EnumList optional=False
member b: __org.qemu_x-StructList optional=False
member c: __org.qemu_x-Union2 optional=False
member d: __org.qemu_x-Alt optional=False
object :obj-anyList-wrapper
member data: anyList optional=False
object :obj-boolList-wrapper
member data: boolList optional=False
object :obj-guest-get-time-arg
member a: int optional=False
member b: int optional=True
object :obj-guest-sync-arg
member arg: any optional=False
object :obj-int16List-wrapper
member data: int16List optional=False
object :obj-int32List-wrapper
member data: int32List optional=False
object :obj-int64List-wrapper
member data: int64List optional=False
object :obj-int8List-wrapper
member data: int8List optional=False
object :obj-intList-wrapper
member data: intList optional=False
object :obj-numberList-wrapper
member data: numberList optional=False
object :obj-sizeList-wrapper
member data: sizeList optional=False
object :obj-str-wrapper
member data: str optional=False
object :obj-strList-wrapper
member data: strList optional=False
object :obj-uint16List-wrapper
member data: uint16List optional=False
object :obj-uint32List-wrapper
member data: uint32List optional=False
object :obj-uint64List-wrapper
member data: uint64List optional=False
object :obj-uint8List-wrapper
member data: uint8List optional=False
object :obj-user_def_cmd1-arg
member ud1a: UserDefOne optional=False
object :obj-user_def_cmd2-arg
member ud1a: UserDefOne optional=False
member ud1b: UserDefOne optional=True
alternate AltIntNum
case i: int
case n: number
alternate AltNumInt
case n: number
case i: int
alternate AltNumStr
case n: number
case s: str
alternate AltStrBool
case s: str
case b: bool
alternate AltStrInt
case s: str
case i: int
alternate AltStrNum
case s: str
case n: number
event EVENT_A None
event EVENT_B None
event EVENT_C :obj-EVENT_C-arg
event EVENT_D :obj-EVENT_D-arg
object Empty1
object Empty2
base Empty1
enum EnumOne ['value1', 'value2', 'value3']
object EventStructOne
member struct1: UserDefOne optional=False
member string: str optional=False
member enum2: EnumOne optional=True
object ForceArrays
member unused1: UserDefOneList optional=False
member unused2: UserDefTwoList optional=False
member unused3: TestStructList optional=False
enum MyEnum []
object NestedEnumsOne
member enum1: EnumOne optional=False
member enum2: EnumOne optional=True
member enum3: EnumOne optional=False
member enum4: EnumOne optional=True
enum QEnumTwo ['value1', 'value2']
prefix QENUM_TWO
enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
prefix QTYPE
object TestStruct
member integer: int optional=False
member boolean: bool optional=False
member string: str optional=False
object UserDefA
member boolean: bool optional=False
member a_b: int optional=True
alternate UserDefAlternate
case uda: UserDefA
case s: str
case i: int
object UserDefB
member intb: int optional=False
member a-b: bool optional=True
object UserDefC
member string1: str optional=False
member string2: str optional=False
object UserDefFlatUnion
base UserDefUnionBase
tag enum1
case value1: UserDefA
case value2: UserDefB
case value3: UserDefB
object UserDefFlatUnion2
base UserDefUnionBase
tag enum1
case value1: UserDefC
case value2: UserDefB
case value3: UserDefA
object UserDefNativeListUnion
member type: UserDefNativeListUnionKind optional=False
case integer: :obj-intList-wrapper
case s8: :obj-int8List-wrapper
case s16: :obj-int16List-wrapper
case s32: :obj-int32List-wrapper
case s64: :obj-int64List-wrapper
case u8: :obj-uint8List-wrapper
case u16: :obj-uint16List-wrapper
case u32: :obj-uint32List-wrapper
case u64: :obj-uint64List-wrapper
case number: :obj-numberList-wrapper
case boolean: :obj-boolList-wrapper
case string: :obj-strList-wrapper
case sizes: :obj-sizeList-wrapper
case any: :obj-anyList-wrapper
enum UserDefNativeListUnionKind ['integer', 's8', 's16', 's32', 's64', 'u8', 'u16', 'u32', 'u64', 'number', 'boolean', 'string', 'sizes', 'any']
object UserDefOne
base UserDefZero
member string: str optional=False
member enum1: EnumOne optional=True
object UserDefOptions
member i64: intList optional=True
member u64: uint64List optional=True
member u16: uint16List optional=True
member i64x: int optional=True
member u64x: uint64 optional=True
object UserDefTwo
member string0: str optional=False
member dict1: UserDefTwoDict optional=False
object UserDefTwoDict
member string1: str optional=False
member dict2: UserDefTwoDictDict optional=False
member dict3: UserDefTwoDictDict optional=True
object UserDefTwoDictDict
member userdef: UserDefOne optional=False
member string: str optional=False
object UserDefUnionBase
base UserDefZero
member string: str optional=False
member enum1: EnumOne optional=False
object UserDefZero
member integer: int optional=False
event __ORG.QEMU_X-EVENT __org.qemu_x-Struct
alternate __org.qemu_x-Alt
case __org.qemu_x-branch: str
case b: __org.qemu_x-Base
object __org.qemu_x-Base
member __org.qemu_x-member1: __org.qemu_x-Enum optional=False
enum __org.qemu_x-Enum ['__org.qemu_x-value']
object __org.qemu_x-Struct
base __org.qemu_x-Base
member __org.qemu_x-member2: str optional=False
member wchar-t: int optional=True
object __org.qemu_x-Struct2
member array: __org.qemu_x-Union1List optional=False
object __org.qemu_x-Union1
member type: __org.qemu_x-Union1Kind optional=False
case __org.qemu_x-branch: :obj-str-wrapper
enum __org.qemu_x-Union1Kind ['__org.qemu_x-branch']
object __org.qemu_x-Union2
base __org.qemu_x-Base
tag __org.qemu_x-member1
case __org.qemu_x-value: __org.qemu_x-Struct2
command __org.qemu_x-command :obj-__org.qemu_x-command-arg -> __org.qemu_x-Union1
gen=True success_response=True
command guest-get-time :obj-guest-get-time-arg -> int
gen=True success_response=True
command guest-sync :obj-guest-sync-arg -> any
gen=True success_response=True
command user_def_cmd None -> None
gen=True success_response=True
command user_def_cmd1 :obj-user_def_cmd1-arg -> None
gen=True success_response=True
command user_def_cmd2 :obj-user_def_cmd2-arg -> UserDefTwo
gen=True success_response=True
Reference in New Issue View Git Blame Copy Permalink