Unix FD to Windows File Handles mapping.

[Bruno Albuquerque]

FWIIW, got it to work by loading ntdll.dll and getting the proc to the
wine_server_fd_to_handle() function and using it on the fd. After that I
could use Win32 functions on the handle as suggested. It is kinda funny
that I can use a handle to the underlying fd but I can not use the fd.

In any case, thanks for all your help.

On Sun, Dec 22, 2019 at 10:00 AM Bruno Albuquerque <bga at gmail.com> wrote:

> Thanks.
>
> My question is now how to access that function from my Windows program as
> it does not seem to be directly available (i.e. in a importable header
> file). In any cae, is  it similar to _get_osfhandle()? I was considering
> using it (it is documented by Microsoft) but I also failed at including
> "msvcrt/io.h" (not found).
>
>
> On Sun, Dec 22, 2019 at 8:12 AM Alexandre Julliard <julliard at winehq.org>
> wrote:
>
>> Zebediah Figura <z.figura12 at gmail.com> writes:
>>
>> > On 12/22/19 6:40 AM, Gabriel Ivăncescu wrote:
>> >> On 12/21/19 5:34 PM, Bruno Albuquerque wrote:
>> >>> Thanks. That led me to the init_user_process_params() where it seems
>> >>> stdin/stdout/stderr are mapped to the running Windows program. I
>> could
>> >>> not find any code that would do anything with other inherited opened
>> fds
>> >>> and that led me to think that there is really no special handling and
>> it
>> >>> somehow just happens to work with a winelib program (most
>> likely because
>> >>> it has a bigger Linux surface to it).
>> >>>
>> >>> Based on this, I guess what I really want to know is:
>> >>>
>> >>> 1 - Does a non-winelib Windows program have access to opened fds
>> >>> inherited during a fork/exec of Wine?
>> >>> 2 - If so, is there a way to actually use those fds in the Windows
>> program?
>> >>>
>> >>>
>> >>
>> >> Hi Bruno,
>> >>
>> >> I'm not sure if this is feasible to you, but keep in mind that
>> "Windows
>> >> programs" ran under Wine are technically still running on Linux. So
>> you
>> >> still have access to Linux syscalls (but not libraries, unless you
>> load
>> >> them manually, which is not worth it).
>> >>
>> >> One possible hack to do this in a "generic" way would be:
>> >>
>> >> 1) Use an exception handler in your app.
>> >>
>> >> 2) Call the 'uname' system call to make sure the returned sysname is
>> >> 'Linux'. If the syscall results in an exception, then it's obviously
>> not
>> >> running on Linux (it could be running on Windows), so do the necessary
>> >> thing there.
>> >
>> > There's also wine_get_host_version(), exported from ntdll, which would
>> > probably be easier.
>> >
>> > In order to get access to file descriptors in the first place, you can
>> > use the counterpart wine_server_handle_to_fd() [also exported from
>> ntdll].
>>
>> Or use wine_server_fd_to_handle() and call Win32 APIs instead of direct
>> syscalls, that's even easier...
>>
>> --
>> Alexandre Julliard
>> julliard at winehq.org
>>
>>
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