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From: Christian Brauner <christian@brauner.io>
To: Andy Lutomirski <luto@kernel.org>
Cc: Tycho Andersen <tycho@tycho.ws>,
	Daniel Colascione <dancol@google.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Jann Horn <jannh@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Aleksa Sarai <cyphar@cyphar.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	Tim Murray <timmurray@google.com>,
	linux-man <linux-man@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v1 2/2] signal: add procfd_signal() syscall
Date: Tue, 20 Nov 2018 01:32:50 +0100
Message-ID: <20181120003247.a776bej54baxqoxv@brauner.io> (raw)
In-Reply-To: <CALCETrWyuQvTtksN1J1XbCFPka_rLOaFqa5W==EvGQvoaf9f3Q@mail.gmail.com>

On Mon, Nov 19, 2018 at 04:27:49PM -0800, Andy Lutomirski wrote:
> On Mon, Nov 19, 2018 at 3:07 PM Tycho Andersen <tycho@tycho.ws> wrote:
> > > These tools also care about ioctls. Adding a system call is a pain,
> > > but the solution is to make adding system calls less of a pain, not to
> > > permanently make the Linux ABI worse.
> >
> > For user-defined values of "worse" :)
> >
> 
> I tend to agree with Tycho here.  But I'm wondering if it might be
> worth considering a better ioctl.
> 
> /me dons flame-proof hat
> 
> We could do:
> 
> long better_ioctl(int fd, u32 nr, const void *inbuf, size_t inlen,
> const void *outbuf, size_t outlen);

I'm the writer of this patch so take this with a grain of salt.
I think it is a bad idea to stop this patch and force us to introduce a
new type of ioctl().
An ioctl() is also not easy to use for this task because we want to add
a siginfo_t argument which I actually think provides value and makes
this interface more useful.

> 
> and have a central table in the kernel listing all possible nr values
> along with which driver they belong to.  We could have a sane
> signature and get rid of the nr collision problem.
> 
> The major problem I see is that u32 isn't really enough to have a sane
> way to allow out-of-tree drivers to use this, and that we can't
> readily use anything bigger than u32 without indirection because we're
> out of syscall argument space.

  reply index

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-19 10:32 [PATCH v1 0/2] proc: allow signaling processes via file descriptors Christian Brauner
2018-11-19 10:32 ` [PATCH v1 1/2] proc: get process file descriptor from /proc/<pid> Christian Brauner
2018-11-19 15:32   ` Andy Lutomirski
2018-11-19 18:20     ` Christian Brauner
2018-11-19 10:32 ` [PATCH v1 2/2] signal: add procfd_signal() syscall Christian Brauner
2018-11-19 15:45   ` Andy Lutomirski
2018-11-19 15:57     ` Daniel Colascione
2018-11-19 18:39     ` Christian Brauner
2018-11-19 15:59   ` Daniel Colascione
2018-11-19 18:29     ` Christian Brauner
2018-11-19 19:02       ` Eric W. Biederman
2018-11-19 19:31         ` Christian Brauner
2018-11-19 19:39           ` Daniel Colascione
2018-11-19 17:10   ` Eugene Syromiatnikov
2018-11-19 18:23     ` Christian Brauner
2018-11-19 17:14   ` Eugene Syromiatnikov
2018-11-19 20:28   ` Aleksa Sarai
2018-11-19 20:55     ` Christian Brauner
2018-11-19 21:13       ` Christian Brauner
2018-11-19 21:18       ` Aleksa Sarai
2018-11-19 21:20         ` Christian Brauner
2018-11-19 21:21         ` Christian Brauner
2018-11-19 21:25           ` Aleksa Sarai
2018-11-19 21:26           ` Daniel Colascione
2018-11-19 21:36             ` Aleksa Sarai
2018-11-19 21:37             ` Christian Brauner
2018-11-19 21:41               ` Daniel Colascione
2018-11-20  4:59                 ` Eric W. Biederman
2018-11-20 10:31                   ` Christian Brauner
2018-11-21 21:39                     ` Serge E. Hallyn
2018-11-19 21:23         ` Aleksa Sarai
2018-11-22  7:41           ` Serge E. Hallyn
2018-11-19 22:39   ` Tycho Andersen
2018-11-19 22:49     ` Daniel Colascione
2018-11-19 23:07       ` Tycho Andersen
2018-11-20  0:27         ` Andy Lutomirski
2018-11-20  0:32           ` Christian Brauner [this message]
2018-11-20  0:34             ` Andy Lutomirski
2018-11-20  0:49           ` Daniel Colascione
2018-11-22  7:48     ` Serge E. Hallyn
2018-11-19 23:35   ` kbuild test robot
2018-11-19 23:37   ` kbuild test robot
2018-11-19 23:45     ` Christian Brauner
2018-11-28 21:45   ` Joey Pabalinas
2018-11-28 22:05     ` Christian Brauner
2018-11-28 23:02       ` Joey Pabalinas
2018-11-19 10:32 ` [PATCH] procfd_signal.2: document procfd_signal syscall Christian Brauner
2018-11-20 13:29   ` Michael Kerrisk (man-pages)
2018-11-28 20:59   ` Florian Weimer
2018-11-28 21:12     ` Christian Brauner

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