Date: Mon, 9 Mar 2009 23:35:58 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Timothy Redaelli <timothy@redaelli.eu> Cc: freebsd-hackers@freebsd.org Subject: Re: lockf: Invalid argument on pipe Message-ID: <alpine.BSF.2.00.0903092335060.92752@fledge.watson.org> In-Reply-To: <ac9bf7980903091448w1c3b8405la2a0084e5a947a05@mail.gmail.com> References: <ac9bf7980903091448w1c3b8405la2a0084e5a947a05@mail.gmail.com>
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On Mon, 9 Mar 2009, Timothy Redaelli wrote:
> Why can't I do a lockf on a file descriptor that does not point a real file
> (such as stderr, stdout, or a character device)?
>
> Since it works under NetBSD, Linux, Solaris. For portability between systems
> I hope I can do it under FreeBSD.
>
> The following code is simple, but It reproduce the problem. Under
> non-FreeBSD systems, It will block before the puts. Instead under FreeBSD
> the lockf calls return error and, so, the lock does not works.
Could you file a PR for this, with pretty much this e-mail and sample code
included? There's no real reason not for it to work other than that it is
likely not implemented for devfs; that should be easy to fix it but opening a
PR will help us keep track of the fact that it wants to be fixed.
thanks,
Robert N M Watson
Computer Laboratory
University of Cambridge
>
> Any suggest?
>
> <snip>
> #include <stdio.h>
> #include <unistd.h>
> #include <stdlib.h>
> #include <string.h>
>
> int main(int argc, char *argv[]) {
> char tmp[256];
>
> if (lockf(2, F_LOCK, 0) == -1)
> perror("lock");
> snprintf (tmp, 256, "%s XXX", argv[0]);
> if (!argv[1] || strcmp(argv[1], "XXX"))
> system(tmp);
> puts("You should see it only after ctrl+c");
> return EXIT_SUCCESS;
> }
> <end snip>
>
> --
> Timothy Redaelli
> IT Consultant
> Email: timothy@redaelli.eu
> Mobile: +39 (338) 1187273
> WWW: http://www.redaelli.eu/
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