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From: Florian Weimer <fweimer@redhat.com>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,  libc-alpha@sourceware.org
Subject: Re: [PATCH] [GLIBC RFC] clone3: add CLONE3_RESET_SIGHAND
References: <20191008134417.16113-1-christian.brauner@ubuntu.com>
	<5cab2cbb-e72b-4eb0-5271-1a90c4e8de95@linaro.org>
	<20191009104830.w2fkr4m3lrkfowxq@wittgenstein>
	<87bluq18po.fsf@oldenburg2.str.redhat.com>
	<20191009111200.rfqlk5lgityhi6rl@wittgenstein>
	<87zhiayvxc.fsf@oldenburg2.str.redhat.com>
	<20191009115846.xs4uou6c2x67pqz7@wittgenstein>
Date: Wed, 09 Oct 2019 12:01:00 -0000
In-Reply-To: <20191009115846.xs4uou6c2x67pqz7@wittgenstein> (Christian
	Brauner's message of "Wed, 9 Oct 2019 13:58:47 +0200")
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* Christian Brauner:

>> With this construct, the application programmer needs to remember which
>> flags are old and new (predate and postdate known_flags).  It's too easy
>> to make mistakes there.
>> 
>> What about this?
>> 
>>   pid_t pid = clone3 (&args, sizeof (args));
>>   if (pid < 0)
>>     return -1;
>> 
>>   if (args.known_flags == 0)
>>     args.known_flags = CLONE3_INITIALLY_SUPPORTED_FLAGS;
>> 
>>   if (args.known_flags & NEW_FLAG_I_CARE_ABOUT)
>>     /* Kernel does support the known_flags extension and does
>>        support the feature I care about.  */
>> 
>> We could hide this in the clone3 wrapper for glibc if we start out with
>> a struct clone_args that has this member.
>
> So the kernel semantics I suggested but when the kernel does not support
> it have and doesn't set it have glibc set this?

Exactly.

> Yeah, that sounds like a good idea to me!

Good.  Please get this into the kernel. 8-)

Thanks,
Florian