Re: [PATCH 2/5] util/oslib-win32: Add a helper to get the Windows version

[Bin Meng]

On Wed, Jul 27, 2022 at 9:18 PM Konstantin Kostiuk <kkostiuk@redhat.com> wrote:
>
>
>
> On Wed, Jul 27, 2022 at 2:58 PM Bin Meng <bmeng.cn@gmail.com> wrote:
>>
>> On Wed, Jul 27, 2022 at 6:00 PM Daniel P. Berrangé <berrange@redhat.com> 
>> wrote:
>> >
>> > On Wed, Jul 27, 2022 at 05:38:27PM +0800, Bin Meng wrote:
>> > > On Wed, Jul 27, 2022 at 4:50 PM Yan Vugenfirer <yvugenfi@redhat.com> 
>> > > wrote:
>> > > >
>> > > > On Wed, Jul 27, 2022 at 10:43 AM Bin Meng <bmeng.cn@gmail.com> wrote:
>> > > > >
>> > > > > From: Bin Meng <bin.meng@windriver.com>
>> > > > >
>> > > > > This adds a helper to get the Windows version via the RtlGetVersion
>> > > > > call, for QEMU codes to determine the Windows version at run-time.
>> > > > >
>> > > > > Signed-off-by: Xuzhou Cheng <xuzhou.cheng@windriver.com>
>> > > > > Signed-off-by: Bin Meng <bin.meng@windriver.com>
>> > > > > ---
>> > > > >
>> > > > >  include/sysemu/os-win32.h |  2 ++
>> > > > >  util/oslib-win32.c        | 15 +++++++++++++++
>> > > > >  2 files changed, 17 insertions(+)
>> > > > >
>> > > > > diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h
>> > > > > index edc3b38a57..1e324026a4 100644
>> > > > > --- a/include/sysemu/os-win32.h
>> > > > > +++ b/include/sysemu/os-win32.h
>> > > > > @@ -204,6 +204,8 @@ ssize_t qemu_recv_wrap(int sockfd, void *buf, 
>> > > > > size_t len, int flags);
>> > > > >  ssize_t qemu_recvfrom_wrap(int sockfd, void *buf, size_t len, int 
>> > > > > flags,
>> > > > >                             struct sockaddr *addr, socklen_t 
>> > > > > *addrlen);
>> > > > >
>> > > > > +void os_get_win_version(RTL_OSVERSIONINFOEXW *info);
>> > > > > +
>> > > > >  #ifdef __cplusplus
>> > > > >  }
>> > > > >  #endif
>> > > > > diff --git a/util/oslib-win32.c b/util/oslib-win32.c
>> > > > > index 5723d3eb4c..6d2387b9ff 100644
>> > > > > --- a/util/oslib-win32.c
>> > > > > +++ b/util/oslib-win32.c
>> > > > > @@ -547,3 +547,18 @@ int qemu_msync(void *addr, size_t length, int 
>> > > > > fd)
>> > > > >       */
>> > > > >      return qemu_fdatasync(fd);
>> > > > >  }
>> > > > > +
>> > > > > +void os_get_win_version(RTL_OSVERSIONINFOEXW *info)
>> > > > > +{
>> > > > > +    typedef LONG (WINAPI *rtl_get_version_t)(PRTL_OSVERSIONINFOEXW);
>> > > > > +
>> > > > > +    /* RtlGetVersion is available starting with Windows 2000 */
>> > > > > +    HMODULE module = GetModuleHandle("ntdll");
>> > > > > +    PVOID fun = GetProcAddress(module, "RtlGetVersion");
>> > > > > +    rtl_get_version_t rtl_get_version = (rtl_get_version_t)fun;
>> > > > > +
>> > > > > +    info->dwOSVersionInfoSize = sizeof(RTL_OSVERSIONINFOEXW);
>> > > > > +    rtl_get_version(info);
>> > > > The original function, when it was present in qemu-ga, tested that
>> > > > getting the function address succeeded.
>> > > > I think this test should be kept.
>> > > > See below:
>> > > > -    PVOID fun = GetProcAddress(module, "RtlGetVersion");
>> > > > -    if (fun == NULL) {
>> > > > -        error_setg(errp, QERR_QGA_COMMAND_FAILED,
>> > > > -            "Failed to get address of RtlGetVersion");
>> > > > -        return;
>> > > > -    }
>> > > >
>> > >
>> > > Please see the comment:
>> > >
>> > > /* RtlGetVersion is available starting with Windows 2000 */
>> > >
>> > > I don't think we need that check.
>> >
>> > In include/qemu/osdep.h we have
>> >
>> > /* as defined in sdkddkver.h */
>> > #ifndef _WIN32_WINNT
>> > #define _WIN32_WINNT 0x0601 /* Windows 7 API (should be in sync with glib) 
>> > */
>> > #endif
>> >
>> > so do we even need to have the GetProcAddress calls at all ?
>> >
>> > Surely we can just  '#include <ddk/ntddk.h>' and call
>> > RtlGetVersion directly at compile time ?
>> >
>>
>> I believe #include <ddk/ntddk.h> is used in the kernel mode driver
>> programming environment.
>> In the user space we will have to use the ntdll exported symbol.
>>
>> I cannot locate a Microsoft doc that tells us to call RtlGetVersion
>> directly in the user space.
>
>
> From MS docs: RtlGetVersion is the kernel-mode equivalent of the user-mode 
> GetVersionEx function in the Windows SDK.
> So you can use GetVersionEx instread.
>

Unfortunately this does not work. GetVersionEx is deprecated since Windows 8.1

Regards,
Bin