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Date: Wed, 10 Nov 2021 08:29:32 +0900
To: cygwin@cygwin.com
Subject: Re: Another pipe-related problem?
Message-Id: <20211110082932.3e33bae9364db0dda0c57d16@nifty.ne.jp>
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From: Takashi Yano via Cygwin <cygwin@cygwin.com>
Reply-To: Takashi Yano <takashi.yano@nifty.ne.jp>
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On Wed, 10 Nov 2021 08:22:45 +0900
Takashi Yano wrote:
> On Tue, 9 Nov 2021 09:11:28 -0500
> Ken Brown wrote:
> > I'll have to reproduce the hang myself in order to test this (or maybe you could 
> > test it), but I now have a new guess: If the read call above keeps failing with 
> > EINTR, then we're in an infinite loop.  This could happen because of the 
> > following code in fhandler_pipe::raw_read:
> > 
> >    DWORD waitret = cygwait (read_mtx, timeout);
> >    switch (waitret)
> >      {
> >      case WAIT_OBJECT_0:
> >        break;
> >      case WAIT_TIMEOUT:
> >        set_errno (EAGAIN);
> >        len = (size_t) -1;
> >        return;
> >      default:
> >        set_errno (EINTR);
> >        len = (size_t) -1;
> >        return;
> >      }
> > 
> > Takashi, is EINTR really the appropriate errno in the default case?  Isn't 
> > cygwait supposed to handle signals?
> 
> I assume cygwait() returns WAIT_SIGNALED when signalled
> by SIGINT, SIGTERM, SIGTSTP, etc...  In this case, EINTR
> should return I think.
> 
> Is it wrong?

Ah, if SA_RESTART is set, we should continue to read even
if signalled...

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

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