From: Al Viro <firstname.lastname@example.org>
To: Christian Brauner <email@example.com>
Cc: David Howells <firstname.lastname@example.org>,
email@example.com, Arnd Bergmann <firstname.lastname@example.org>,
Subject: Re: [PATCH 0/4] uapi, vfs: Change the mount API UAPI [ver #2]
Date: Thu, 16 May 2019 17:50:22 +0100 [thread overview]
Message-ID: <20190516165021.GD17978@ZenIV.linux.org.uk> (raw)
On Thu, May 16, 2019 at 06:31:52PM +0200, Christian Brauner wrote:
> On Thu, May 16, 2019 at 05:22:59PM +0100, Al Viro wrote:
> > On Thu, May 16, 2019 at 12:52:04PM +0100, David Howells wrote:
> > >
> > > Hi Linus, Al,
> > >
> > > Here are some patches that make changes to the mount API UAPI and two of
> > > them really need applying, before -rc1 - if they're going to be applied at
> > > all.
> > I'm fine with 2--4, but I'm not convinced that cloexec-by-default crusade
> > makes any sense. Could somebody give coherent arguments in favour of
> > abandoning the existing conventions?
> So as I said in the commit message. From a userspace perspective it's
> more of an issue if one accidently leaks an fd to a task during exec.
> Also, most of the time one does not want to inherit an fd during an
> exec. It is a hazzle to always have to specify an extra flag.
> As Al pointed out to me open() semantics are not going anywhere. Sure,
> no argument there at all.
> But the idea of making fds cloexec by default is only targeted at fds
> that come from separate syscalls. fsopen(), open_tree_clone(), etc. they
> all return fds independent of open() so it's really easy to have them
> cloexec by default without regressing anyone and we also remove the need
> for a bunch of separate flags for each syscall to turn them into
> cloexec-fds. I mean, those for syscalls came with 4 separate flags to be
> able to specify that the returned fd should be made cloexec. The other
> way around, cloexec by default, fcntl() to remove the cloexec bit is way
> saner imho.
Re separate flags - it is, in principle, a valid argument. OTOH, I'm not
sure if they need to be separate - they all have the same value and
I don't see any reason for that to change...
Only tangentially related, but I wonder if something like close_range(from, to)
would be a more useful approach... That kind of open-coded loops is not
rare in userland and kernel-side code can do them much cheaper. Something
/* that exec is sensitive */
/* we don't want anything past stderr here */
on the userland side of thing. Comments?
next prev parent reply other threads:[~2019-05-16 16:50 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-16 11:52 [PATCH 0/4] uapi, vfs: Change the mount API UAPI [ver #2] David Howells
2019-05-16 11:52 ` [PATCH 1/4] uapi, fs: make all new mount api fds cloexec by default " David Howells
2019-05-16 11:52 ` [PATCH 2/4] uapi, fsopen: use square brackets around "fscontext" " David Howells
2019-05-16 11:52 ` [PATCH 3/4] uapi, x86: Fix the syscall numbering of the mount API syscalls " David Howells
2019-05-16 13:01 ` Christian Brauner
2019-05-16 11:52 ` [PATCH 4/4] uapi: Wire up the mount API syscalls on non-x86 arches " David Howells
2019-05-16 13:01 ` Christian Brauner
2019-05-16 14:56 ` Geert Uytterhoeven
2019-05-16 14:59 ` Christian Brauner
2019-05-16 16:22 ` [PATCH 0/4] uapi, vfs: Change the mount API UAPI " Al Viro
2019-05-16 16:31 ` Al Viro
2019-05-16 16:31 ` Christian Brauner
2019-05-16 16:50 ` Al Viro [this message]
2019-05-16 17:01 ` Christian Brauner
2019-05-16 20:23 ` Dmitry V. Levin
2019-05-17 6:54 ` Christian Brauner
2019-05-17 7:01 ` Christian Brauner
2019-05-17 7:13 ` David Howells
2019-05-17 7:25 ` Miklos Szeredi
2019-05-17 7:27 ` Christian Brauner
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