1999-10-01 Roland McGrath <roland@baalperazim.frob.com>

1999-10-01  Roland McGrath  <roland@baalperazim.frob.com>

	* hurd/hurdioctl.c (rectty_dtable): Renamed to install_ctty.
	(install_ctty): Do the changing of the cttyid port cell here, inside
	the critical section while we holding the dtable lock.
	(_hurd_setcttyid, tiocsctty, tiocnotty): Use that instead of changing
	the port cell and calling rectty_dtable.
	(_hurd_locked_install_cttyid): New function, split out of install_ctty.
	(install_ctty): Use it inside a critical section, with the lock held.
	* sysdeps/mach/hurd/setsid.c (__setsid): Use
	_hurd_locked_install_cttyid to effect the cttyid and dtable changes
	after proc_setsid, having held the dtable lock throughout.
	* hurd/dtable.c (ctty_new_pgrp): With the dtable lock held, check the
	cttyid port for null and bail out early if so.  The dtable lock
	serializes us after any cttyid change and its associated dtable update.