DMARC-Filter:	OpenDMARC Filter v1.4.2 delorie.com 53F8LtFc1384895
Authentication-Results:	delorie.com; dmarc=pass (p=none dis=none) header.from=cygwin.com
Authentication-Results:	delorie.com; spf=pass smtp.mailfrom=cygwin.com
DKIM-Filter:	OpenDKIM Filter v2.11.0 delorie.com 53F8LtFc1384895
Authentication-Results:	delorie.com;
	dkim=pass (1024-bit key, unprotected) header.d=cygwin.com header.i=@cygwin.com header.a=rsa-sha256 header.s=default header.b=q9pq6Xht
X-Recipient:	archive-cygwin AT delorie DOT com
DKIM-Filter:	OpenDKIM Filter v2.11.0 sourceware.org 1129F385780D
DKIM-Signature:	v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1744705314;
	bh=L5iCeSBWRlnJihYKZbOxhy8hFTsJQSDe24S5B9rWElc=;
	h=Date:To:Cc:Subject:In-Reply-To:References:List-Id:
	List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe:
	From:Reply-To:From;
	b=q9pq6XhtoYHXFGcJI6K24+36bLg2BwFpL1dy0eGVLegrQf9In3lUIqGADfdGLvJvd
	3T45a+YQHv8XyLwdfZWSJo5P3IQL3kRJeVu++p8GbOPGTvWLaa3j/c5kLtiH8aoAyM
	hpt89cWQ+n4KNiXxSokNEf6n8DE5fsOXx2SAEuJc=
X-Original-To:	cygwin AT cygwin DOT com
Delivered-To:	cygwin AT cygwin DOT com
DMARC-Filter:	OpenDMARC Filter v1.4.2 sourceware.org 125DC385841C
ARC-Filter:	OpenARC Filter v1.0.0 sourceware.org 125DC385841C
ARC-Seal:	i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1744705250; cv=none;
	b=kLlclTieyXWXetnF51NzcbL7kWLa2EdQnA6UJaN2ppl2mVp3WxBBRJbICBIVf7V6ZhTDFXCvk7YEruGcnfmz0XpBFf1IUx5QWEE0bq8QjuEycWFq6ogZVvEBJEZp8bN3mncSHI6IOgFFP6zfSilyu34t5KrrbMpdQPXe7K5gj80=
ARC-Message-Signature:	i=1; a=rsa-sha256; d=sourceware.org; s=key;
	t=1744705250; c=relaxed/simple;
	bh=8ZWYTsgeCgAdBfuKuhY9RCAmuuIwgS/5uGn1C6Bnw2k=;
	h=Date:From:To:Subject:Message-Id:Mime-Version:DKIM-Signature;
	b=jMshUW7+49OpYu120riH7axr2+dXHwXOMi5zEv3r16xdgXL+Wjd2mKoY0ZPjbIRme3QdP2SVXrsJbGBEgXBR4swDW2zrr5NiIGrePTQ0TgcLFyn1UXwAdwfouCzf7tUrhc9FXjgHR5r6JJI2FpF9zithpN/3s3HEncfYAfmfV0A=
ARC-Authentication-Results:	i=1; server2.sourceware.org
DKIM-Filter:	OpenDKIM Filter v2.11.0 sourceware.org 125DC385841C
Date:	Tue, 15 Apr 2025 17:20:46 +0900
To:	cygwin AT cygwin DOT com
Cc:	Bruno Haible <bruno AT clisp DOT org>
Subject:	Re: /dev/null regression in Cygwin 3.6.1
Message-Id:	<20250415172046.da05eb6b5b161cd8ab79cbb0@nifty.ne.jp>
In-Reply-To:	<19390375.kOAnuia59f@nimes>
References:	<10514352 DOT ICPdZLu4VQ AT nimes>
	<19390375 DOT kOAnuia59f AT nimes>
X-Mailer:	Sylpheed 3.7.0 (GTK+ 2.24.30; i686-pc-mingw32)
Mime-Version:	1.0
X-BeenThere:	cygwin AT cygwin DOT com
X-Mailman-Version:	2.1.30
List-Id:	General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe:	<https://cygwin.com/mailman/options/cygwin>,
	<mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive:	<https://cygwin.com/pipermail/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe:	<https://cygwin.com/mailman/listinfo/cygwin>,
	<mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From:	Takashi Yano via Cygwin <cygwin AT cygwin DOT com>
Reply-To:	Takashi Yano <takashi DOT yano AT nifty DOT ne DOT jp>
Errors-To:	cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com
Sender:	"Cygwin" <cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com>

On Mon, 14 Apr 2025 15:03:16 +0200
Bruno Haible wrote:
> Here's a smaller reproducer.
> 
> ============================ foo.c ============================
> #include <stdio.h>
> #include <windows.h>
> #include <io.h>
> 
> int main ()
> {
>   HANDLE h = (HANDLE) _get_osfhandle (0);
>   fprintf (stderr, "h = 0x%08x\n", h);
>   fprintf (stderr, "FileType is CHAR ? %d\n", GetFileType (h) == FILE_TYPE_CHAR);
>   int ret = WaitForSingleObject (h, 0);
>   if (ret == WAIT_OBJECT_0)
>     fprintf (stderr, "WaitForSingleObject -> WAIT_OBJECT_0\n");
>   else if (ret == WAIT_TIMEOUT)
>     fprintf (stderr, "WaitForSingleObject -> WAIT_TIMEOUT\n");
>   else if (ret == WAIT_ABANDONED)
>     fprintf (stderr, "WaitForSingleObject -> WAIT_ABANDONED\n");
>   else if (ret == WAIT_FAILED)
>     fprintf (stderr, "WaitForSingleObject -> WAIT_FAILED\n");
> }
> ===============================================================
> Compile this file as a native Windows program (mingw for example).
> Then, in a Cygwin shell window, do
> $ ./a < /dev/null
> 
> Result in 3.4.6:
> 
> h = 0x000001e8
> FileType is CHAR ? 1
> WaitForSingleObject -> WAIT_OBJECT_0
> 
> Result in 3.6.1:
> 
> h = 0x00000358
> FileType is CHAR ? 1
> WaitForSingleObject -> WAIT_TIMEOUT
> 
> > Looking through the commits between 3.6.0 and 3.6.1, the most likely culprit
> > is commit d750786e7de013b58e2968eeb6a7fd59dcc535c9 .
> 
> Especially since this commit modified select.cc, removing a comment
>   /* TODO: Buffer really full or non-Cygwin reader? */
> and here we are exactly in that case: a non-Cygwin process reading from
> Cygwin's /dev/null.
> 
> Takashi Yano, can you please look at it and restore the previous behaviour?

Thanks for the new testcase. I think the issue has been fixed in:
cygwin-3.7.0-0.68.g37c49decc835 (Test)
Please test.

-- 
Takashi Yano <takashi DOT yano AT nifty DOT ne DOT jp>

-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple

- Raw text -