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@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@winehq.org> wrote:
Zebediah Figura <z.figura12@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@winehq.org