Re: [PATCH v2 3/3] linux: Add pidfd_getpid

[Luca Boccassi <luca.boccassi@gmail.com>]

On Thu, 20 Apr 2023 at 15:20, Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> This interface allows to obtain the associated pid ID from the
> process file descriptor.  It is done by parsing the procps fdinfo
> information.  Its prototype is:
>
>    pid_t pidfd_getpid (int fd)
>
> It returns the associated pid or -1 in case of an error and set the
> errno accordingly.  The possible errno values are the smae from
> open, read, and close (used on procps parsing), along with:
>
>    - EINVAL if the FP is negative (similar to fexecve).
>
>    - EBADF if the FD does not have a PID associated of if the fdinfo
>      fields contains a value larger than pid_t.
>
>    - EREMOTE if the PID is in a separate namespace.
>
>    - ESRCH if the process is already terminated.
>
> Checked on x86_64-linux-gnu on Linux 4.15 (no CLONE_PID or waitid
> support), Linux 5.15 (only clone support), and Linux 5.19 (full
> support including clone3).

Acked-by: Luca Boccassi <bluca@debian.org>