Date: Tue, 10 Sep 2002 09:30:03 -0700 (PDT) From: alo@louko.com (Antti Louko) To: freebsd-bugs@FreeBSD.org Subject: Re: misc/41331: Pthread library open sets O_NONBLOCK flag and causes unnecessary EAGAIN errors especially with /dev/stdout. Message-ID: <200209101630.g8AGU36d091105@freefall.freebsd.org>
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The following reply was made to PR misc/41331; it has been noted by GNATS. From: alo@louko.com (Antti Louko) To: archie@packetdesign.com Cc: freebsd-gnats-submit@FreeBSD.org, deischen@freebsd.org Subject: Re: misc/41331: Pthread library open sets O_NONBLOCK flag and causes unnecessary EAGAIN errors especially with /dev/stdout. Date: 10 Sep 2002 16:26:31 -0000 Sender: archie@dellroad.org Date: Tue, 10 Sep 2002 08:26:40 -0700 From: Archie Cobbs <archie@packetdesign.com> Organization: Packet Design X-Accept-Language: en CC: freebsd-gnats-submit@FreeBSD.org, deischen@freebsd.org Antti Louko wrote: > I just tried it in 4.6 Release and 4.6.2 and it still occurs. I think this is a kernel bug, rather than a pthread bug. What's happening is that the file descriptor associated with /dev/stdout is "inheriting" the flags associated with file descriptor 0. This happens on both -stable and -current. This seems like broken behavior to me: flags should be associated with the file descriptor, not the underlying device or entity. But I don't know what the "official" semantics of /dev/stdout are supposed to be. The program below demonstrates the problem: $ cc -g -Wall -o flags flags.c $ ./flags O_NONBLOCK is set But the O_NONBLOCK is not set in the kernel. It is probably set in /usr/src/lib/libc_r/uthread/uthread_fd.c (which sets O_NONBLOCK flags for fds in range 0..2) or somewhere else in libc_r because it doesn't happen without thread library. But someone who is familiar with the pthreads library should check what should happen. I don't feel competent to fix this. Regards, Antti To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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