From: Takashi Yano <takashi.yano@nifty.ne.jp>
To: cygwin@cygwin.com
Subject: Re: Another pipe-related problem?
Date: Wed, 10 Nov 2021 09:16:13 +0900 [thread overview]
Message-ID: <20211110091613.26a636e789fe36a098412f1b@nifty.ne.jp> (raw)
In-Reply-To: <20211110084822.fa32acb567bd26ab43c393bd@nifty.ne.jp>
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.yano@nifty.ne.jp>
next prev parent reply other threads:[~2021-11-10 0:16 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-08 13:12 Henry S. Thompson
2021-11-08 14:35 ` Ken Brown
2021-11-08 18:52 ` Ken Brown
2021-11-09 10:55 ` Henry S. Thompson
2021-11-09 14:11 ` Ken Brown
2021-11-09 14:47 ` Henry S. Thompson
2021-11-09 22:16 ` Ken Brown
2021-11-09 22:20 ` Ken Brown
2021-11-10 2:53 ` Ken Brown
2021-11-10 3:51 ` Backwoods BC
2021-11-10 14:47 ` Ken Brown
2021-11-10 17:23 ` Henry S. Thompson
2021-11-10 18:03 ` Ken Brown
2021-11-10 18:42 ` Henry S. Thompson
2021-11-10 23:07 ` Andrey Repin
2021-11-11 11:06 ` Andrey Repin
2021-11-11 14:16 ` Ken Brown
2021-12-08 21:09 ` XEmacs versus Cygwin 3.3 (was Re: Another pipe-related problem?) Henry S. Thompson
2021-12-09 8:39 ` Aidan Kehoe
2021-11-09 23:22 ` Another pipe-related problem? Takashi Yano
2021-11-09 23:29 ` Takashi Yano
2021-11-09 23:48 ` Takashi Yano
2021-11-10 0:16 ` Takashi Yano [this message]
2021-11-10 0:37 ` Takashi Yano
2021-11-10 2:02 ` Ken Brown
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211110091613.26a636e789fe36a098412f1b@nifty.ne.jp \
--to=takashi.yano@nifty.ne.jp \
--cc=cygwin@cygwin.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).