On Wed, 10 Nov 2021 08:48:22 +0900
Takashi Yano wrote:
> On Wed, 10 Nov 2021 08:29:32 +0900
> Takashi Yano wrote:
> > 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...
>
> So, should this be like following?
>
> restart_wait_read_mtx:
> DWORD waitret = cygwait (read_mtx, timeout, cw_sig_eintr);
> switch (waitret)
> {
> case WAIT_OBJECT_0:
> break;
> case WAIT_TIMEOUT:
> set_errno (EAGAIN);
> len = (size_t) -1;
> return;
> case WAIT_SIGNALED:
> if (_my_tls.call_signal_handler ())
> goto restart_wait_read_mtx;
> set_errno (EINTR);
> len = (size_t) -1;
> return;
> default:
> /* Should not reach here. */
> __seterrno ();
> len = (size_t) -1;
> return;
> }
No, we don't have to do that because cygwait() do the same
internally. cygwain() returns WAIT_SIGNALED when signalled
only if SA_RESTART is not set. So, the current code LGTM.
--
Takashi Yano <takashi.y...@nifty.ne.jp>
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