[PATCH 0/2] Return appropriate handle by _get_osfhandle() and GetStdHandle().
Ken Brown
kbrown@cornell.edu
Mon Mar 22 17:02:46 GMT 2021
[Still CC Marco]
On 3/22/2021 7:43 AM, Corinna Vinschen via Cygwin-patches wrote:
> [CC Marco]
>
> On Mar 22 08:07, Takashi Yano via Cygwin-patches wrote:
>> 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);
>> }
>
> Why on earth is cmake using Windows functions on Cygwin at all???
> It's not as if it actually requires Windows functionality on our
> platform.
Out of curiosity, I took a quick glance at the cmake code. It appears that this
code is designed to support running cmake in a Console. I don't think that
should be needed any more, if it ever was.
> Marco, any input? Any chance to drop this Windows stuff from the Cygwin
> code path in cmake?
I think the following might suffice (untested):
--- a/Source/kwsys/Terminal.c
+++ b/Source/kwsys/Terminal.c
@@ -10,7 +10,7 @@
#endif
/* Configure support for this platform. */
-#if defined(_WIN32) || defined(__CYGWIN__)
+#if defined(_WIN32)
# define KWSYS_TERMINAL_SUPPORT_CONSOLE
#endif
#if !defined(_WIN32)
Ken
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