/* * proc_enterpgrp: move p to a new or existing process group (and session). * * If we are creating a new pgrp, the pgid should equal * the calling process' pid. * If is only valid to enter a process group that is in the session * of the process. * Also mksess should only be set if we are creating a process group * * Only called from sys_setsid, sys_setpgid and posix_spawn/spawn_return. */