From: Christoph Hellwig <hch@lst.de>
To: Christian Brauner <brauner@kernel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, cyphar@cyphar.com, lennart@poettering.net,
linux-fsdevel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: fd == 0 means AT_FDCWD BPF_OBJ_GET commands
Date: Wed, 17 May 2023 14:05:28 +0200 [thread overview]
Message-ID: <20230517120528.GA17087@lst.de> (raw)
In-Reply-To: <20230517-allabendlich-umgekehrt-8cc81f8313ac@brauner>
On Wed, May 17, 2023 at 11:11:24AM +0200, Christian Brauner wrote:
> Adding fsdevel so we're aware of this quirk.
>
> So I'm not sure whether this was ever discussed on fsdevel when you took
> the decision to treat fd 0 as AT_FDCWD or in general treat fd 0 as an
> invalid value.
I've never heard of this before, and I think it is compltely
unacceptable. 0 ist just a normal FD, although one that happens to
have specific meaning in userspace as stdin.
>
> If it was discussed then great but if not then I would like to make it
> very clear that if in the future you decide to introduce custom
> semantics for vfs provided infrastructure - especially when exposed to
> userspace - that you please Cc us.
I don't think it's just the future. We really need to undo this ASAP.
next prev parent reply other threads:[~2023-05-17 12:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-16 0:13 [PATCH bpf-next 0/3] Add O_PATH-based BPF_OBJ_PIN and BPF_OBJ_GET support Andrii Nakryiko
2023-05-16 0:13 ` [PATCH bpf-next 1/3] bpf: support O_PATH FDs in BPF_OBJ_PIN and BPF_OBJ_GET commands Andrii Nakryiko
2023-05-16 8:52 ` Jiri Olsa
2023-05-16 18:02 ` Andrii Nakryiko
2023-05-16 9:07 ` Christian Brauner
2023-05-16 18:02 ` Andrii Nakryiko
2023-05-17 9:11 ` fd == 0 means AT_FDCWD " Christian Brauner
2023-05-17 12:05 ` Christoph Hellwig [this message]
2023-05-17 16:17 ` Alexei Starovoitov
2023-05-17 21:48 ` Alexei Starovoitov
2023-05-18 8:38 ` Christian Brauner
2023-05-18 14:30 ` Theodore Ts'o
2023-05-18 16:25 ` Alexei Starovoitov
2023-05-18 16:33 ` Matthew Wilcox
2023-05-18 17:22 ` Christian Brauner
2023-05-18 17:20 ` Christian Brauner
2023-05-18 17:33 ` Linus Torvalds
2023-05-18 18:21 ` Christian Brauner
2023-05-18 18:26 ` Alexei Starovoitov
2023-05-18 18:57 ` Linus Torvalds
2023-05-19 4:44 ` Alexei Starovoitov
2023-05-19 8:13 ` Christian Brauner
2023-05-19 14:27 ` Theodore Ts'o
2023-05-19 17:51 ` Linus Torvalds
2023-05-23 7:49 ` Lennart Poettering
2023-05-23 17:25 ` Andrii Nakryiko
2023-08-26 4:27 ` Al Viro
2023-05-18 21:56 ` Andrii Nakryiko
2023-05-16 0:13 ` [PATCH bpf-next 2/3] libbpf: add opts-based bpf_obj_pin() API and add support for path_fd Andrii Nakryiko
2023-05-16 0:13 ` [PATCH bpf-next 3/3] selftests/bpf: add path_fd-based BPF_OBJ_PIN and BPF_OBJ_GET tests Andrii Nakryiko
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