Works similarly to OpenBSD's "closefrom(2)": The closefrom() call deletes all descriptors numbered fd and higher from the per-process file descriptor table.

CreateMasterAndConsole will open /dev/ptmx on the host and retreive the pts name for use as the pty slave inside the container.

look in /proc to find the process start time so that we can verify that this pid has started after ourself.

Returns a nil slice and nil error if the xattr is not set.

OpenPtmx opens /dev/ptmx, i.e.

OpenTerminal is a clone of os.OpenFile without the O_CLOEXEC used to open the pty slave inside the container namespace.

Ptsname retrieves the name of the first available pts for the given master.

Unlockpt unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by f.