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Date:   Sat, 25 Jan 2020 21:42:56 -0800
From:   Tycho Andersen <tycho@tycho.ws>
To:     Sargun Dhillon <sargun@sargun.me>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux Containers <containers@lists.linux-foundation.org>,
        Linux API <linux-api@vger.kernel.org>,
        Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
        Christian Brauner <christian.brauner@ubuntu.com>
Subject: Re: [PATCH 3/4] seccomp: Add SECCOMP_USER_NOTIF_FLAG_PIDFD to get
 pidfd on listener trap
Message-ID: <20200126054256.GB4151@cisco>
References: <20200124091743.3357-1-sargun@sargun.me>
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 <20200124180332.GA4151@cisco>
 <CAMp4zn_WXwxJ6Md4rgFzdAY_xea4TmVDdQc1iJDObEMm5Yc79g@mail.gmail.com>
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On Fri, Jan 24, 2020 at 12:09:37PM -0800, Sargun Dhillon wrote:
> On Fri, Jan 24, 2020 at 10:03 AM Tycho Andersen <tycho@tycho.ws> wrote:
> >
> > On Fri, Jan 24, 2020 at 01:17:42AM -0800, Sargun Dhillon wrote:
> > > Currently, this just opens the group leader of the thread that triggere
> > > the event, as pidfds (currently) are limited to group leaders.
> >
> > I don't love the semantics of this; when they're not limited to thread
> > group leaders any more, we won't be able to change this. Is that work
> > far off?
> >
> > Tycho
> 
> We would be able to change this in the future if we introduced a flag like
> SECCOMP_USER_NOTIF_FLAG_PIDFD_THREAD which would send a
> pidfd that's for the thread, and not just the group leader. The flag could
> either be XOR with SECCOMP_USER_NOTIF_FLAG_PIDFD, or
> could require both. Alternatively, we can rename
> SECCOMP_USER_NOTIF_FLAG_PIDFD to
> SECCOMP_USER_NOTIF_FLAG_GROUP_LEADER_PIDFD.

Ok, but then isn't this just another temporary API? Seems like it's
worth waiting until the Right Way exists.

Tycho