[PATCH 0/2] Return appropriate handle by _get_osfhandle() and GetStdHandle().

[Takashi Yano]

On Sun, 21 Mar 2021 17:44:27 +0900
Takashi Yano wrote:
> On Sun, 21 Mar 2021 13:01:24 +0900
> Takashi Yano wrote:
> > Takashi Yano (2):
> >   Cygwin: syscalls.cc: Make _get_osfhandle() return appropriate handle.
> >   Cygwin: pty: Add hook for GetStdHandle() to return appropriate handle.
> > 
> >  winsup/cygwin/fhandler_tty.cc | 19 +++++++++++++++++++
> >  winsup/cygwin/syscalls.cc     | 13 ++++++++++++-
> >  2 files changed, 31 insertions(+), 1 deletion(-)
> 
> I submitted these patches, however, I still wonder if we really
> need these patches. I cannot imagine the situation where handle
> itself is needed rather than file descriptor.
> 
> However, following cygwin apps/dlls call _get_osfhandle():
> ccmake.exe
> cmake.exe
> cpack.exe
> ctest.exe
> ddrescue.exe
> 
> And also, following cygwin apps/dlls call GetStdHandle():
> ccmake.exe
> cmake.exe
> cpack.exe
> ctest.exe
> run.exe
> cygusb0.dll
> tk86.dll
> 
> in my installation.
> 
> Therefore, some of these apps/dlls may need these patches...

I looked into cmake source and found the patch exactly for
this issue. Therefore, it seems better to fix this. 

/* Get the Windows handle for a FILE stream.  */
static HANDLE kwsysTerminalGetStreamHandle(FILE* stream)
{
  /* Get the C-library file descriptor from the stream.  */
  int fd = fileno(stream);

#  if defined(__CYGWIN__)
  /* Cygwin seems to have an extra pipe level.  If the file descriptor
     corresponds to stdout or stderr then obtain the matching windows
     handle directly.  */
  if (fd == fileno(stdout)) {
    return GetStdHandle(STD_OUTPUT_HANDLE);
  } else if (fd == fileno(stderr)) {
    return GetStdHandle(STD_ERROR_HANDLE);
  }
#  endif

  /* Get the underlying Windows handle for the descriptor.  */
  return (HANDLE)_get_osfhandle(fd);
}


-- 
Takashi Yano <takashi.yano@nifty.ne.jp>