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From:   Todd Kjos <tkjos@google.com>
Date:   Thu, 10 Mar 2022 11:33:20 -0800
Message-ID: <CAHRSSEy5_h9LJB4q5_OJA7fSq=ROo68UaK+hdPz-Vj-wac1Qhg@mail.gmail.com>
Subject: Re: [RFC v3 7/8] binder: use __kernel_pid_t and __kernel_uid_t for userspace
To:     "T.J. Mercier" <tjmercier@google.com>
Cc:     Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jonathan Corbet <corbet@lwn.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Christian Brauner <brauner@kernel.org>,
        Hridya Valsaraju <hridya@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Benjamin Gaignard <benjamin.gaignard@linaro.org>,
        Liam Mark <lmark@codeaurora.org>,
        Laura Abbott <labbott@redhat.com>,
        Brian Starkey <Brian.Starkey@arm.com>,
        John Stultz <john.stultz@linaro.org>,
        Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Shuah Khan <shuah@kernel.org>, kaleshsingh@google.com,
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On Wed, Mar 9, 2022 at 8:52 AM T.J. Mercier <tjmercier@google.com> wrote:
>
> The kernel interface should use types that the kernel defines instead of
> pid_t and uid_t, whose definiton is owned by libc. This fixes the header
> so that it can be included without first including sys/types.h.
>
> Signed-off-by: T.J. Mercier <tjmercier@google.com>
> ---
>  include/uapi/linux/android/binder.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
> index 169fd5069a1a..aa28454dbca3 100644
> --- a/include/uapi/linux/android/binder.h
> +++ b/include/uapi/linux/android/binder.h
> @@ -289,8 +289,8 @@ struct binder_transaction_data {
>
>         /* General information about the transaction. */
>         __u32           flags;
> -       pid_t           sender_pid;
> -       uid_t           sender_euid;
> +       __kernel_pid_t  sender_pid;
> +       __kernel_uid_t  sender_euid;

Are we guaranteed that this does not affect the UAPI at all? Userspace
code using this definition will have to run with kernels using the old
definition and visa-versa.

>         binder_size_t   data_size;      /* number of bytes of data */
>         binder_size_t   offsets_size;   /* number of bytes of offsets */
>
> --
> 2.35.1.616.g0bdcbb4464-goog
>