Re: [Qemu-devel] [RFC PATCH v2 01/17] fuzz: Move initialization from main to qemu_init

[Darren Kenny]

On Mon, Aug 05, 2019 at 09:43:06AM +0200, Paolo Bonzini wrote:
> On 05/08/19 09:11, Oleinik, Alexander wrote:
> > Using this, we avoid needing a special case to break out of main(),
> > early, when initializing the fuzzer, as we can just call qemu_init.
> > There is still a #define around main(), since it otherwise conflicts
> > with the libfuzzer main().
> >
> > Signed-off-by: Alexander Oleinik <address@hidden>
> > ---
> >  include/sysemu/sysemu.h |  5 +++++
> >  vl.c                    | 25 +++++++++++++++++++++++--
> >  2 files changed, 28 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> > index 984c439ac9..a63d5ccce3 100644
> > --- a/include/sysemu/sysemu.h
> > +++ b/include/sysemu/sysemu.h
> > @@ -184,6 +184,8 @@ QemuOpts *qemu_get_machine_opts(void);
> >
> >  bool defaults_enabled(void);
> >
> > +int qemu_init(int argc, char **argv, char **envp);
> > +
> >  extern QemuOptsList qemu_legacy_drive_opts;
> >  extern QemuOptsList qemu_common_drive_opts;
> >  extern QemuOptsList qemu_drive_opts;
> > @@ -197,4 +199,7 @@ extern QemuOptsList qemu_global_opts;
> >  extern QemuOptsList qemu_mon_opts;
> >  extern QemuOptsList qemu_semihosting_config_opts;
> >
> > +#ifdef CONFIG_FUZZ
> > +int real_main(int argc, char **argv, char **envp);
> > +#endif
> >  #endif
> > diff --git a/vl.c b/vl.c
> > index 130a389712..914bb9b2de 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -130,6 +130,10 @@ int main(int argc, char **argv)
> >  #include "sysemu/iothread.h"
> >  #include "qemu/guest-random.h"
> >
> > +#ifdef CONFIG_FUZZ
> > +#include "tests/libqtest.h"
> > +#endif
>
> Why is this #include needed?
>
> If you leave out the changes to introduce real_main, the patch can be
> committed independent of the rest.  Those can be introduced in patch 2
> or even 12 ("Add fuzzer skeleton").

The build actually fails for me due to this include, because it has it's own
and different declaration of qtest_init:

 In file included from vl.c:134:
 .../qemu-upstream-libfuzz/./tests/libqtest.h:57:13: error: conflicting types 
for 'qtest_init'
 QTestState *qtest_init(const char *extra_args);
             ^
 .../qemu-upstream-libfuzz/include/sysemu/qtest.h:27:6: note: previous 
declaration is here
 void qtest_init(const char *qtest_chrdev, const char *qtest_log, Error **errp);
      ^
 In file included from vl.c:134:
 .../qemu-upstream-libfuzz/./tests/libqtest.h:640:35: error: too few arguments 
to function call, expected 3, have 1
     global_qtest = qtest_init(args);
                    ~~~~~~~~~~     ^
 .../qemu-upstream-libfuzz/include/sysemu/qtest.h:27:1: note: 'qtest_init' 
declared here
 void qtest_init(const char *qtest_chrdev, const char *qtest_log, Error **errp);
 ^
 2 errors generated.

(It's probably a separate issue as to why there are 2 functions with
the same name, are not static and have different signatures in the
first place)

Thanks,

Darren.