On 11/9/2021 7:37 PM, Takashi Yano via Cygwin wrote:
On Wed, 10 Nov 2021 09:16:13 +0900
Takashi Yano wrote:
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...
[...]
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.
Ah, however, should we handle WAIT_CANCELED here and call
pthread::static_cancel_self() as following?
DWORD waitret = cygwait (read_mtx, timeout);
switch (waitret)
{
case WAIT_OBJECT_0:
break;
case WAIT_TIMEOUT:
set_errno (EAGAIN);
len = (size_t) -1;
return;
WAIT_SIGNALED:
set_errno (EINTR);
len = (size_t) -1;
return;
WAIT_CANCELED:
pthread::static_cancel_self ();
/* NOTREACHED */
default:
/* Should not reach here. */
__seterrno ();
len = (slze_t) -1;
return;
}
This looks better to me. I think the default case actually could be reached if
WFMO returns WAIT_FAILED (admittedly unlikely).
Ken
--
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
