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Hermes SMTP Server) with ESMTPA ID 8b42282e344c528a0be615aec6237442; Sat, 15 Nov 2025 21:29:02 +0000 (UTC) Message-ID: <6c26eea2-6f90-f48a-9488-e7480f086c70@netscape.net> Date: Sat, 15 Nov 2025 13:29:00 -0800 Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: RFC: Serial port DTR/RTS - O_ Content-Language: en-US To: "H. Peter Anvin" , "Maciej W. Rozycki" Cc: Greg KH , Theodore Ts'o , Maarten Brock , "linux-serial@vger.kernel.org" , "linux-api@vger.kernel.org" , LKML References: <20251110201933.GH2988753@mit.edu> <0F8021E8-F288-4669-8195-9948844E36FD@zytor.com> <20251111035143.GJ2988753@mit.edu> <2025111214-doily-anyway-b24b@gregkh> <6DBB5931-ACD4-4174-9FCE-96C45FFC4603@zytor.com> <2025111241-domestic-moonstone-f75f@gregkh> <2025111227-equipment-magnetism-1443@gregkh> <14b1bc5c-83ac-431f-a53b-14872024b969@zytor.com> From: Ned Ulbricht In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Mailer: WebService/1.1.24652 mail.backend.jedi.jws.acl:role.jedi.acl.token.atz.jws.hermes.aol On 11/14/25 10:53, H. Peter Anvin wrote: > On November 14, 2025 10:49:09 AM PST, "Maciej W. Rozycki" wrote: >> On Thu, 13 Nov 2025, H. Peter Anvin wrote: >> >>>> I think this is going to be the most difficult. I don't remember why I >>>> rejected the old submission, but maybe it would have modified the >>>> existing behaviour? A new open flag "O_DO_NOT_TOUCH_ANYTHING" might be >>>> the simplest? >>>> >>> >>> Okay, to I'm going to toss out a couple suggestions for naming: >>> >>> O_(PRE|FOR|N|NO)?(INIT|CONFIG|START)(DEV|HW|IO)? >>> O_(NO?RESET|PREPARE)(DEV|HW|IO)? >>> O_NO?TOUCH >>> O_NYET ("not yet") >>> >>> I think my personal preference at the moment is either O_NYET or O_PRECONFIG >>> or O_NYET; although it is perhaps a bit more "use case centric" than "what >>> actual effect it has" I think it might be clearer. A -DEV, -HW or -IO suffix >>> would seem to needlessly preclude it being used for future similar use cases >>> for files that are not device nodes. >> >> Hmm, I'm inconvinced about any of these. >> >> How about O_FDONLY, to reflect that you are after a file descriptor only [snip] Hi all, Resurrecting a (private email) discussion from a few years back now, my personal preferences are: (1) O_KEEP (2) O_TTY_KEEP (3) O_TTY_NOINIT. (Of course, naming an open() flag has got to be a paradigmatic invitation for bike-shedding...) It's worth pointing out, though, that even though O_TTY_INIT doesn't generally appear in linux headers, that particular flag is documented in POSIX to have at least incompatible --perhaps even strictly opposite-- behavior compared with this new proposed flag. See The Open Group Base Specifications Issue 8 (IEEE Std 1003.1-2024): | 11.1.1 Opening a Terminal Device File | | 3. ... The terminal parameters can be set to values that ensure the | terminal behaves in a conforming manner by means of the O_TTY_INIT | open flag.... https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap11.html | open, openat — open file | | O_TTY_INIT https://pubs.opengroup.org/onlinepubs/9799919799/ That's what motivates my first-glance preference to name this new flag, which will have approximately opposite behavior, as O_TTY_NOINIT. But as a generic abstraction, I more prefer O_KEEP. Ned