From: Al Viro <viro@ZenIV.linux.org.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: gregkh <gregkh@linuxfoundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHES] tty ioctls cleanups, compat and not only
Date: Thu, 13 Sep 2018 21:31:45 +0100 [thread overview]
Message-ID: <20180913203145.GU19965@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CAK8P3a2LpC6sw5KQ_6kcXKNfgUXkjsxbFkD30kdMgQjurGgy9Q@mail.gmail.com>
On Thu, Sep 13, 2018 at 01:19:42PM +0200, Arnd Bergmann wrote:
> On Thu, Sep 13, 2018 at 4:31 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > See vfs.git#work.tty-ioctl. Completely untested, should seriously
> > clean the things up wrt compat. Remaining problems (aside of the bugs
> > introduced in it, of course):
> > * TIOCSERGSTRUCT must die; it's present only in amiserial and it's
> > _vile_; look at what it copies out and weep.
> > * synclink_gt has proper compat handling for its private ioctls;
> > other synclink drivers (with the same ioctls) do not.
> > * dgnc definitely has buggered ioctls - structs full of longs are
> > bloody bad idea for passing around. It's in staging, and I'd say that it
> > needs the userland ABI fixed.
> > * cyclades, rocket, moxa and mxser probably have non-trivial
> > problems with their private ioctls; I hadn't looked into those.
> > * n_gsm needs ->compat_ioctl(); easy to do, I just hadn't done it
> > yet.
> > * ipwireless might or might not need compat_ioctl (PPP stuff in it);
> > not sure.
> > * ldisc private ioctls need more work. Hadn't gone there yet.
> > Generic ioctls should be fine - they never reach ->compat_ioctl() with this
> > series.
>
> I looked at all the new patches, looks all good to me. When I did my
> (incomplete) analysis, I found a couple more things that could be
> included in the series if we want to:
>
> * TIOCSERGWILD/TIOCSERSWILD are obsolete and never do
> anything useful, but the return code is inconsistent: ENOTTY
> in compat mode vs 0 in uart_ioctl, plus a printk for amiserial.
> If we want to keep it around rather than deleting it completely,
> it should be marked as compatible.
Yes. Not sure if we want to - the only user is setserial(8), with
-W Do wild interrupt initialization and exit. This option is no
longer relevant in Linux kernels after version 2.1.
What's more, rc.serial does *not* use it since 2.15 and even in 2.14 it wouldn't
have failed the boot - just whine (truthfully) "Cannot scan for wild interrupts"
on stderr and continue with the rest of the script. The same goes at least as
far back as setserial-2.02. That's what MCC had; if you want to check something
earlier, you'll probably have to ask tytso, but I very much doubt that anything
of that vintage will work with the current kernels *or* that anyone cared to
abort the script in question on setserial -W /dev/cua0 failing to start with.
So I'd seriously suggest removing those altogether. I mean, sure, we can carry
explicit "obsolete, quietly return 0 on those" indefinitely, but that really feels
over the top. Time to bury the body, unless somebody objects...
> * PPPIOCGCHAN/PPPIOCGUNIT are implemented by multiple
> ldisc variants, marking them as compatible would save us from
> implementing a comp_ioctl method for each one separately.
> These are also used on some things that are not ttys though,
> so we can't remove them from fs/compat_ioctl.c yet.
Worse - there's ipwireless, which implements it in tty_operations ->ioctl().
> * FIONREAD/TIOCINQ and TIOCOUTQ also appear multiple
> times and could be added to that list but not removed from
> fs/compat_ioctl.c (I think the other users are all in sockets, so
> adding them in both might be sufficient)
Pipes as well.
> * SIOCGIFNAME, SIOCGIFENCAP, SIOCSIFENCAP,
> SIOCSIFHWADDR, SIOCSKEEPALIVE, SIOCGKEEPALIVE,
> SIOCSOUTFILL, and SIOCGOUTFILL are in the tty_ioctl
> functions for multiple protocol handlers, comparable to
> the PPP ones.
Very definitely shared with sockets, and I prefer to handle the tty-side cases
in ldisc ->compat_ioctl().
next prev parent reply other threads:[~2018-09-13 20:31 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-13 2:31 [PATCHES] tty ioctls cleanups, compat and not only Al Viro
2018-09-13 2:40 ` [PATCH 01/50] presence of RS485 ioctls has been unconditional since 2014 Al Viro
2018-09-13 2:40 ` [PATCH 02/50] move compat handling of tty ioctls to tty_compat_ioctl() Al Viro
2018-09-14 15:15 ` Arnd Bergmann
2018-09-14 18:16 ` gregkh
2018-09-14 19:38 ` Arnd Bergmann
2018-09-15 18:51 ` gregkh
2018-09-13 2:40 ` [PATCH 03/50] tty_ioctl(): drop FIONBIO handling Al Viro
2018-09-13 2:40 ` [PATCH 04/50] mos7720: bury dead TIOCM... in ->ioctl() Al Viro
2018-09-14 13:31 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 05/50] tty_ioctl(): start taking TIOC[SG]SERIAL into separate methods Al Viro
2018-09-14 13:22 ` Johan Hovold
2018-09-14 15:18 ` Al Viro
2018-09-14 16:23 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 06/50] simserial: switch to ->[sg]et_serial() Al Viro
2018-09-13 2:40 ` [PATCH 07/50] fwserial: " Al Viro
2018-09-13 2:40 ` [PATCH 08/50] greybus/uart: " Al Viro
2018-09-14 13:31 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 09/50] amiserial: " Al Viro
2018-09-13 10:33 ` Greg Kroah-Hartman
2018-10-11 17:58 ` Geert Uytterhoeven
2018-10-13 5:36 ` Al Viro
2018-09-13 2:40 ` [PATCH 10/50] cyclades: " Al Viro
2018-09-13 2:40 ` [PATCH 11/50] ipwireless: " Al Viro
2018-09-14 12:00 ` David Sterba
2018-09-13 2:40 ` [PATCH 12/50] isicom: " Al Viro
2018-09-13 2:40 ` [PATCH 13/50] moxa: " Al Viro
2018-09-13 2:40 ` [PATCH 14/50] mxser: " Al Viro
2018-09-13 2:40 ` [PATCH 15/50] serial_core: " Al Viro
2018-09-13 2:40 ` [PATCH 16/50] rfcomm: get rid of mentioning TIOC[SG]SERIAL Al Viro
2018-09-13 2:40 ` [PATCH 17/50] usb-serial: begin switching to ->[sg]et_serial() Al Viro
2018-09-14 13:39 ` Johan Hovold
2018-09-14 15:23 ` Al Viro
2018-09-14 15:26 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 18/50] cdc-acm: switch " Al Viro
2018-09-13 2:40 ` [PATCH 19/50] ark3116: switch to ->get_serial() Al Viro
2018-09-14 13:41 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 20/50] f81232: " Al Viro
2018-09-14 13:42 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 21/50] f81534: " Al Viro
2018-09-14 13:43 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 22/50] fdti_sio: switch to ->[sg]et_serial() Al Viro
2018-09-14 13:47 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 23/50] io_edgeport: switch to ->get_serial() Al Viro
2018-09-14 13:58 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 24/50] io_ti: " Al Viro
2018-09-14 13:59 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 25/50] mos7720: " Al Viro
2018-09-14 14:02 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 26/50] mos7840: " Al Viro
2018-09-14 14:07 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 27/50] opticon: " Al Viro
2018-09-14 14:08 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 28/50] pl2303: " Al Viro
2018-09-14 14:08 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 29/50] quatech2: " Al Viro
2018-09-14 14:09 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 30/50] ssu100: " Al Viro
2018-09-14 14:10 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 31/50] ti_usb_3410_5052: switch to ->[sg]et_serial() Al Viro
2018-09-14 14:12 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 32/50] whiteheat: switch to ->get_serial() Al Viro
2018-09-14 14:15 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 33/50] usb_wwan: switch to ->[sg]et_serial() Al Viro
2018-09-14 14:18 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 34/50] complete ->[sg]et_serial() switchover Al Viro
2018-09-14 14:20 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 35/50] synclink: reduce pointless checks in ->ioctl() Al Viro
2018-09-13 2:40 ` [PATCH 36/50] take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl() Al Viro
2018-09-13 2:40 ` [PATCH 37/50] kill capinc_tty_ioctl() Al Viro
2018-09-13 2:40 ` [PATCH 38/50] isdn_tty: TCSBRK{,P} won't reach ->ioctl() Al Viro
2018-09-13 2:40 ` [PATCH 39/50] dgnc: TIOCM... " Al Viro
2018-09-13 2:40 ` [PATCH 40/50] kill the rest of tty COMPAT_IOCTL() entries Al Viro
2018-09-13 10:55 ` Arnd Bergmann
2018-09-13 2:40 ` [PATCH 41/50] dgnc: break-related ioctls won't reach ->ioctl() Al Viro
2018-09-13 11:59 ` Greg Kroah-Hartman
2018-09-13 2:40 ` [PATCH 42/50] remove fallback to drivers for TIOCGICOUNT Al Viro
2018-09-14 14:23 ` Johan Hovold
2018-09-13 2:40 ` [PATCH 43/50] dgnc: leave TIOC[GS]SOFTCAR to ldisc Al Viro
2018-09-13 2:40 ` [PATCH 44/50] dgnc: don't bother with (empty) stub for TCXONC Al Viro
2018-09-13 2:40 ` [PATCH 45/50] gigaset: don't try to printk userland buffer contents Al Viro
2018-09-13 2:40 ` [PATCH 46/50] vt_compat_ioctl(): clean up, use compat_ptr() properly Al Viro
2018-09-13 10:10 ` Arnd Bergmann
2018-09-13 2:40 ` [PATCH 47/50] gigaset: add ->compat_ioctl() Al Viro
2018-09-13 2:40 ` [PATCH 48/50] compat_ioctl - kill keyboard ioctl handling Al Viro
2018-09-13 2:40 ` [PATCH 49/50] pty: fix compat ioctls Al Viro
2018-09-13 2:40 ` [PATCH 50/50] synclink_gt(): fix compat_ioctl() Al Viro
2018-09-13 11:19 ` [PATCHES] tty ioctls cleanups, compat and not only Arnd Bergmann
2018-09-13 20:31 ` Al Viro [this message]
2018-09-13 20:56 ` Arnd Bergmann
2018-09-14 2:27 ` Al Viro
2018-09-14 8:21 ` Arnd Bergmann
2018-09-14 15:10 ` Al Viro
2018-09-14 15:33 ` Arnd Bergmann
2018-09-13 11:59 ` Greg Kroah-Hartman
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