Commit Graph

12 Commits

Author SHA1 Message Date
Eric Blake
25dad6e8d5
qmp: Fix reference-counting of qnull on empty output visit
Commit 6c2f9a15 ensured that we would not return NULL when the
caller used an output visitor but had nothing to visit. But
in doing so, it added a FIXME about a reference count leak
that could abort qemu in the (unlikely) case of SIZE_MAX such
visits (more plausible on 32-bit). (Although that commit
suggested we might fix it in time for 2.5, we ran out of time;
fortunately, it is unlikely enough to bite that it was not
worth worrying about during the 2.5 release.)

This fixes things by documenting the internal contracts, and
explaining why the internal function can return NULL and only
the public facing interface needs to worry about qnull(),
thus avoiding over-referencing the qnull_ global object.

It does not, however, fix the stupidity of the stack mixing
up two separate pieces of information; add a FIXME to explain
that issue, which will be fixed shortly in a future patch.

Backports commit a86156401559cb4401cf9ecc704faeab6fc8bb19 from qemu
2018-02-20 08:07:31 -05:00
Eric Blake
1f54314cbb
qapi: Drop unused 'kind' for struct/enum visit
visit_start_struct() and visit_type_enum() had a 'kind' argument
that was usually set to either the stringized version of the
corresponding qapi type name, or to NULL (although some clients
didn't even get that right). But nothing ever used the argument.
It's even hard to argue that it would be useful in a debugger,
as a stack backtrace also tells which type is being visited.

Therefore, drop the 'kind' argument as dead.

Backports commit 337283dffbb5ad5860ed00408a5fd0665c21be07 from qemu
2018-02-19 23:43:54 -05:00
Eric Blake
844c136945
qapi: Swap 'name' in visit_* callbacks to match public API
As explained in the previous patches, matching argument order of
'name, &value' to JSON's "name":value makes sense. However,
while the last two patches were easy with Coccinelle, I ended up
doing this one all by hand. Now all the visitor callbacks match
the main interface.

The compiler is able to enforce that all clients match the changed
interface in visitor-impl.h, even where two pointers are being
swapped, because only one of the two pointers is const (if that
were not the case, then C's looseness on treating 'char *' like
'void *' would have made review a bit harder).

Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-19 23:36:52 -05:00
Markus Armbruster
f93438ba43
qapi: Introduce a first class 'any' type
It's first class, because unlike '**', it actually works, i.e. doesn't
require 'gen': false.

'**' will go away next.

Backports commit 28770e057f265a4e70bcbdfc2447cce7b5f2dc19 from qemu
2018-02-19 17:46:58 -05:00
Eric Blake
3aba81d5aa
qapi: Drop unused error argument for list and implicit struct
No backend was setting an error when ending the visit of a list or
implicit struct, or when moving to the next list node. Make the
callers a bit easier to follow by making this a part of the contract,
and removing the errp argument - callers can then unconditionally end
an object as part of cleanup without having to think about whether a
second error is dominated by a first, because there is no second
error.

A later patch will then tackle the larger task of splitting
visit_end_struct(), which can indeed set an error.

Backports commit 08f9541dec51700abef0c37994213164ca4e4fc9 from qemu
2018-02-19 12:59:54 -05:00
Eric Blake
eeffd97458
qapi: Make all visitors supply uint64 callbacks
Our qapi visitor contract supports multiple integer visitors,
but left the type_uint64 visitor as optional (falling back on
type_int64); which in turn can lead to awkward behavior with
numbers larger than INT64_MAX (the user has to be aware of
twos complement, and deal with negatives).

This patch does not address the disparity in handling large
values as negatives. It merely moves the fallback from uint64
to int64 from the visitor core to the visitors, where the issue
can actually be fixed, by implementing the missing type_uint64()
callbacks on top of the respective type_int64() callbacks, and
with a FIXME comment explaining why that's wrong.

With that done, we now have a type_uint64() callback in every
driver, so we can make it mandatory from the core. And although
the type_int64() callback can cover the entire valid range of
type_uint{8,16,32} on valid user input, using type_uint64() to
avoid mixed signedness makes more sense.

Backports commit f755dea79dc81b0d6a8f6414e0672e165e28d8ba from qemu
2018-02-19 11:59:22 -05:00
Eric Blake
5b5299bdee
qapi: Prefer type_int64 over type_int in visitors
The qapi builtin type 'int' is basically shorthand for the type
'int64'. In fact, since no visitor was providing the optional
type_int64() callback, visit_type_int64() was just always falling
back to type_int(), cementing the equivalence between the types.

However, some visitors are providing a type_uint64() callback.
For purposes of code consistency, it is nicer if all visitors
use the paired type_int64/type_uint64 names rather than the
mismatched type_int/type_uint64. So this patch just renames
the signed int callbacks in place, dropping the type_int()
callback as redundant, and a later patch will focus on the
unsigned int callbacks.

Add some FIXMEs to questionable reuse of errp in code touched
by the rename, while at it (the reuse works as long as the
callbacks don't modify value when setting an error, but it's not
a good example to set) - a later patch will then fix those.

No change in functionality here, although further cleanups are
in the pipeline.

Backports commit 4c40314a35816de635e7170eaacdc0c35be83a8a from qemu
2018-02-19 11:53:21 -05:00
Peter Maydell
31e4fcdc5b
qapi: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Backports commit cbf21151906c935d4276268b59429c58546462ae from qemu
2018-02-19 01:29:30 -05:00
Eric Blake
d544d83348
qobject: Use 'bool' for qbool
We require a C99 compiler, so let's use 'bool' instead of 'int'
when dealing with boolean values. There are few enough clients
to fix them all in one pass.

Backports commit fc48ffc39ed1060856475e4320d5896f26c945e8 from qemu
2018-02-17 15:23:09 -05:00
Chris Eagle
fccbcfd4c2 revert to use of g_free to make future qemu integrations easier (#695)
* revert to use of g_free to make future qemu integrations easier

* bracing
2016-12-21 22:28:36 +08:00
Chris Eagle
e46545f722 remove glib dependency by provide compatible replacements 2016-12-18 14:56:58 -08:00
Nguyen Anh Quynh
344d016104 import 2015-08-21 15:04:50 +08:00