This interface allows to obtain the associated process 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 sets the
errno accordingly. The possible errno values are those from open, read,
and close (used on procps parsing), along with:
- EBADF if the FD is negative, does not have a PID associated, or if
the fdinfo fields contain 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_PIDFD or waitid
support), Linux 5.4 (full support), and Linux 6.2.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
pidfd_getfd can fail for a valid pidfd with errno EPERM for various
reasons in a restricted environment. Use FAIL_UNSUPPORTED in that case.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
To check for the pidfd functions pidfd_open, pidfd_getfd, pid_send_signal,
and waitid with P_PIDFD.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
