[PATCH v2 0/3] pidfd: add task path ioctls

[Florian Weimer]

* Chen Linxuan via:

> This series adds PIDFD_GET_EXE, PIDFD_GET_CWD, and PIDFD_GET_ROOT. Each
> ioctl takes no argument and returns a close-on-exec O_PATH file
> descriptor referencing the corresponding task path.  The new ioctls use
> the same ptrace permission check and nonzero-argument rejection as the
> existing pidfd namespace ioctls.

How would one upgrade the O_PATH descriptor to a full descriptor without
a mounted /proc?

Thanks,
Florian