Re: cygwin 3.3.x: another problem that may be related to pipes

[Takashi Yano <takashi.yano@nifty.ne.jp>]

On Tue, 16 Nov 2021 18:45:15 +0900
Takashi Yano wrote:
> Hi Ken,
> 
> I noticed the following while fixing this issue.
> 
> We now noticed that NtWriteFile() may return STATUS_PENDING
> even in nonblocking mode.
> 
> If NtWriteFile() returns STATUS_PENDING in nonblocking mode,
> does not the following 'if' block in raw_write() refer to 
> uninitialized io.Information?
> 
>       while (len1 > 0)
>         {
>           status = NtWriteFile (get_handle (), evt, NULL, NULL, &io,
>                                 (PVOID) ptr, len1, NULL, NULL);
>           if (evt || !NT_SUCCESS (status) || io.Information > 0
>               || len <= PIPE_BUF)
>             break;
>           len1 >>= 1;
>         }
> 
> 'evt' is false if we are in nonblocking mode.
> '!NT_SUCCESS(status)' is false if status == STATUS_PENDING.
> Then io.Information would be referred I think.
> 
> Isn't this another bug in raw_write()?
> 
> What should we do in this case? Should we do like:
> 
>           if (evt || !NT_SUCCESS (status) || status == STATUS_PENDING
>               || io.Information > 0 || len <= PIPE_BUF)
> 
> ?

Answer to myself.

I think moving cygwait(evt, ...) before this 'if' block is the
right thing.

Right? If so, I will submit v3 patch.

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