From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: linasvepstas-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
Chris Metcalf <cmetcalf-kv+TWInifGbQT0dZR+AlfA@public.gmane.org>,
GLIBC Devel <libc-alpha-9JcytcrH/bA+uJoB2kUjGw@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
libc-ports-9JcytcrH/bA+uJoB2kUjGw@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
Subject: Re: [BUG] Generic syscalls -- chmod vs. fchmodat
Date: Tue, 25 Jan 2011 21:04:57 +0100 [thread overview]
Message-ID: <201101252104.58011.arnd@arndb.de> (raw)
In-Reply-To: <20110125183437.7C6C2180999-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org>
On Tuesday 25 January 2011 19:34:37 Roland McGrath wrote:
> I don't think this was part of the original intent when the calls were
> added, but I suppose it makes sense.
More importantly, even if it was never meant this way, anyone could have
assumed that it was and started using the system call in this way.
> > Treating the empty string special for AT_FDCWD is rather pointless, but
> > at least consistent.
>
> I agree about the consistency point. However, one could also call it
> consistent if the empty string fails to resolve when operating on either a
> directory file descriptor or AT_FDCWD but works on a non-directory file
> descriptor.
Yes.
> POSIX does not mandate that *at calls fail with ENOTDIR when
> passed a non-directory file descriptor (it's a "may fail" error, not a
> "shall fail" error). So that behavior would be consistent both with the
> POSIX requirements as I read them, and with the desire you mentioned to let
> the fblahat system call serve to implement fblah as well as blah. Then
> libc would not have to wrap the *at calls with any special check to conform
> to POSIX.
Makes sense.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Roland McGrath <roland@redhat.com>
Cc: linasvepstas@gmail.com, Chris Metcalf <cmetcalf@tilera.com>,
GLIBC Devel <libc-alpha@sourceware.org>,
linux-kernel@vger.kernel.org, libc-ports@sourceware.org,
linux-api@vger.kernel.org, Mike Frysinger <vapier@gentoo.org>
Subject: Re: [BUG] Generic syscalls -- chmod vs. fchmodat
Date: Tue, 25 Jan 2011 21:04:57 +0100 [thread overview]
Message-ID: <201101252104.58011.arnd@arndb.de> (raw)
In-Reply-To: <20110125183437.7C6C2180999@magilla.sf.frob.com>
On Tuesday 25 January 2011 19:34:37 Roland McGrath wrote:
> I don't think this was part of the original intent when the calls were
> added, but I suppose it makes sense.
More importantly, even if it was never meant this way, anyone could have
assumed that it was and started using the system call in this way.
> > Treating the empty string special for AT_FDCWD is rather pointless, but
> > at least consistent.
>
> I agree about the consistency point. However, one could also call it
> consistent if the empty string fails to resolve when operating on either a
> directory file descriptor or AT_FDCWD but works on a non-directory file
> descriptor.
Yes.
> POSIX does not mandate that *at calls fail with ENOTDIR when
> passed a non-directory file descriptor (it's a "may fail" error, not a
> "shall fail" error). So that behavior would be consistent both with the
> POSIX requirements as I read them, and with the desire you mentioned to let
> the fblahat system call serve to implement fblah as well as blah. Then
> libc would not have to wrap the *at calls with any special check to conform
> to POSIX.
Makes sense.
Arnd
next prev parent reply other threads:[~2011-01-25 20:04 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-24 19:57 [BUG] Generic syscalls -- chmod vs. fchmodat Linas Vepstas
2011-01-24 21:05 ` Roland McGrath
2011-01-24 21:32 ` Mike Frysinger
[not found] ` <AANLkTikhKHnR+7DskxYqWXduX4=tpfgsfL4sNYq+4QDq-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-01-25 14:29 ` Arnd Bergmann
2011-01-25 14:29 ` Arnd Bergmann
[not found] ` <201101251529.24779.arnd-r2nGTMty4D4@public.gmane.org>
2011-01-25 17:45 ` Roland McGrath
2011-01-25 17:45 ` Roland McGrath
[not found] ` <20110125174515.C1DC2183C19-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org>
2011-01-25 18:21 ` Arnd Bergmann
2011-01-25 18:21 ` Arnd Bergmann
[not found] ` <201101251921.15184.arnd-r2nGTMty4D4@public.gmane.org>
2011-01-25 18:34 ` Roland McGrath
2011-01-25 18:34 ` Roland McGrath
[not found] ` <20110125183437.7C6C2180999-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org>
2011-01-25 20:04 ` Arnd Bergmann [this message]
2011-01-25 20:04 ` Arnd Bergmann
2011-01-25 18:52 ` Mike Frysinger
2011-01-25 18:52 ` Mike Frysinger
[not found] ` <201101251352.03079.vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
2011-01-25 19:56 ` Eric Blake
2011-01-25 19:56 ` Eric Blake
2011-01-25 20:31 ` Eric Blake
2011-01-25 20:31 ` Eric Blake
2011-01-25 21:32 ` Eric Blake
2011-01-25 21:32 ` Eric Blake
2011-01-25 22:10 ` Linas Vepstas
2011-02-10 18:12 ` Andries Brouwer
[not found] ` <20110210181221.GA19413-ek1Qb6IBo2Pz+pZb47iToQ@public.gmane.org>
2011-02-10 18:17 ` Roland McGrath
2011-02-10 18:17 ` Roland McGrath
2011-02-11 9:11 ` Andreas Schwab
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