Re: [Qemu-devel] [PATCH V8 00/13] monitor: support sub command group in auto completion and help

[Wenchao Xia]

于 2013-8-20 22:04, Luiz Capitulino 写道:
> On Tue, 30 Jul 2013 12:03:11 -0400
> Luiz Capitulino <address@hidden> wrote:
>
> > On Fri, 26 Jul 2013 11:20:29 +0800
> > Wenchao Xia <address@hidden> wrote:
> >
> > > This series make auto completion and help functions works normal for sub
> > > command, by using reentrant functions. In order to do that, global variables
> > > are not directly used in those functions any more. With this series, cmd_table
> > > is a member of structure Monitor so it is possible to create a monitor with
> > > different command table now, auto completion will work in that monitor. In
> > > short, "info" is not treated as a special case now, this series ensure help
> > > and auto complete function works normal for any sub command added in the future.
> > >
> > > Patch 5 replaced cur_mon with rs->mon, it is safe because:
> > > monitor_init() calls readline_init() which initialize mon->rs, result is
> > > mon->rs->mon == mon. Then qemu_chr_add_handlers() is called, which make
> > > monitor_read() function take *mon as its opaque. Later, when user input,
> > > monitor_read() is called, where cur_mon is set to *mon by "cur_mon = opaque".
> > > If qemu's monitors run in one thread, then later in readline_handle_byte()
> > > and readline_comletion(), cur_mon is actually equal to rs->mon, in another
> > > word, it points to the monitor instance, so it is safe to replace *cur_mon
> > > in those functions.
> >
> > I've applied this to qmp-next with the change I suggested for
> > patch 09/13.
>
> Unfortunately this series brakes make check:
>
> GTESTER check-qtest-x86_64
> Broken pipe
> GTester: last random seed: R02S3492bd34f44dd17460851643383be44d
> main-loop: WARNING: I/O thread spun for 1000 iterations
> make: *** [check-qtest-x86_64] Error 1
>
> I debugged it (with some help from Laszlo) and the problem is that it
> broke the human-monitor-command command. Any usage of this command
> triggers the bug like:
>
> { "execute": "human-monitor-command",
>               "arguments": { "command-line": "info registers" } }
>
> It seems simple to fix, I think you just have to initialize
> mon->cmd_table in qmp_human_monitor_command(), but I'd recommend two
> things:
>
>   1. It's better to split off some/all QMP initialization from
>      monitor_init() and call it from qmp_human_monitor_command()
>
>   2. Can you please take the opportunity and test all commands using
>      cur_mon? Just grep for it
>
> Sorry for noticing this only now, but I only run make check before
> sending a pull request (although this very likely shows you didn't
> run it either).
  About the fd related qmp interface, to test it, send_msg() is needed,
which was not supported in python 2, but new added python 3.3. I think
there are three ways to add test cases for fd qmp APIs:
1 test only when python > 3.3.
2 python plus C: compile a .so and call it with ctypes.
3 a new test framework: pure C code to call qmp interfaces.
  Which one do you prefer?

--
Best Regards

Wenchao Xia