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From: Florian Weimer <fweimer@redhat.com>
To: hpa@zytor.com
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
	libc-alpha@sourceware.org, linux-api@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] Linux: Define struct termios2 in <termios.h> under _GNU_SOURCE [BZ #10339]
Date: Tue, 16 Apr 2019 11:59:03 +0200	[thread overview]
Message-ID: <87lg0az2xk.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <A278227C-039B-49F4-B80D-650B785AE225@zytor.com> (hpa's message of "Mon, 15 Apr 2019 08:53:02 -0700")

* hpa:

> Using symbol versioning doesn't really help much since the real
> problem is that struct termios can be passed around in userspace, and
> the interfaces between user space libraries don't have any
> versioning. However, my POC code deals with that too by only seeing
> BOTHER when necessary, so if the structure is extended garbage in the
> extra fields will be ignored unless new baud rates are in use.

That still doesn't solve the problem of changing struct offsets after a
struct field of type struct termios.

> Exporting termios2 to user space feels a bit odd at this stage as it
> would only be usable as a fallback on old glibc. Call it
> kernel_termios2 at least.

I'm not sure why we should do that?  The kernel calls it struct termios2
in its UAPI headers.  If that name is not appropriate, it should be
changed first in the UAPI headers.

Thanks,
Florian

WARNING: multiple messages have this Message-ID (diff)
From: Florian Weimer <fweimer@redhat.com>
To: hpa@zytor.com
Cc: linux-api@vger.kernel.org, libc-alpha@sourceware.org,
	linuxppc-dev@lists.ozlabs.org,
	Adhemerval Zanella <adhemerval.zanella@linaro.org>
Subject: Re: [PATCH] Linux: Define struct termios2 in <termios.h> under _GNU_SOURCE [BZ #10339]
Date: Tue, 16 Apr 2019 11:59:03 +0200	[thread overview]
Message-ID: <87lg0az2xk.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <A278227C-039B-49F4-B80D-650B785AE225@zytor.com> (hpa's message of "Mon, 15 Apr 2019 08:53:02 -0700")

* hpa:

> Using symbol versioning doesn't really help much since the real
> problem is that struct termios can be passed around in userspace, and
> the interfaces between user space libraries don't have any
> versioning. However, my POC code deals with that too by only seeing
> BOTHER when necessary, so if the structure is extended garbage in the
> extra fields will be ignored unless new baud rates are in use.

That still doesn't solve the problem of changing struct offsets after a
struct field of type struct termios.

> Exporting termios2 to user space feels a bit odd at this stage as it
> would only be usable as a fallback on old glibc. Call it
> kernel_termios2 at least.

I'm not sure why we should do that?  The kernel calls it struct termios2
in its UAPI headers.  If that name is not appropriate, it should be
changed first in the UAPI headers.

Thanks,
Florian

  parent reply	other threads:[~2019-04-16  9:59 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-09 10:47 [PATCH] Linux: Define struct termios2 in <termios.h> under _GNU_SOURCE [BZ #10339] Florian Weimer
2019-04-09 10:47 ` Florian Weimer
2019-04-09 15:02 ` hpa
2019-04-09 15:02   ` hpa
2019-04-10  6:50   ` Florian Weimer
2019-04-10  6:50     ` Florian Weimer
2019-04-15 15:54     ` hpa
2019-04-15 15:54       ` hpa
2019-04-09 15:07 ` hpa
2019-04-09 15:07   ` hpa
2019-04-09 16:04   ` Florian Weimer
2019-04-09 16:04     ` Florian Weimer
2019-04-10 20:24 ` Adhemerval Zanella
2019-04-10 20:24   ` Adhemerval Zanella
2019-04-11 11:07   ` Florian Weimer
2019-04-11 11:07     ` Florian Weimer
2019-04-11 12:53     ` Adhemerval Zanella
2019-04-11 12:53       ` Adhemerval Zanella
2019-04-12  7:50       ` Florian Weimer
2019-04-12  7:50         ` Florian Weimer
2019-04-15 12:28         ` Florian Weimer
2019-04-15 12:28           ` Florian Weimer
2019-04-15 15:53         ` hpa
2019-04-15 15:53           ` hpa
2019-04-15 17:22           ` Adhemerval Zanella
2019-04-15 17:22             ` Adhemerval Zanella
2019-04-17 22:04             ` H. Peter Anvin
2019-04-17 22:04               ` H. Peter Anvin
2019-04-18 11:09               ` Adhemerval Zanella
2019-04-18 11:09                 ` Adhemerval Zanella
2019-04-18 14:46                 ` hpa
2019-04-18 14:46                   ` hpa
2019-04-16  9:59           ` Florian Weimer [this message]
2019-04-16  9:59             ` Florian Weimer
2019-04-16 12:11             ` Adhemerval Zanella
2019-04-16 12:11               ` Adhemerval Zanella
2019-04-17 22:06             ` H. Peter Anvin
2019-04-17 22:06               ` H. Peter Anvin
2019-04-17 21:22 ` Joseph Myers
2019-04-17 21:22   ` Joseph Myers

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