tty_tty.c revision 179519
1268899Sbapt/*- 2234949Sbapt * Copyright (c) 2003 Poul-Henning Kamp. All rights reserved. 3234949Sbapt * 4234949Sbapt * Redistribution and use in source and binary forms, with or without 5234949Sbapt * modification, are permitted provided that the following conditions 6234949Sbapt * are met: 7234949Sbapt * 1. Redistributions of source code must retain the above copyright 8234949Sbapt * notice, this list of conditions and the following disclaimer. 9234949Sbapt * 2. Redistributions in binary form must reproduce the above copyright 10234949Sbapt * notice, this list of conditions and the following disclaimer in the 11234949Sbapt * documentation and/or other materials provided with the distribution. 12234949Sbapt * 13234949Sbapt * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14234949Sbapt * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15234949Sbapt * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16234949Sbapt * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17234949Sbapt * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18234949Sbapt * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19234949Sbapt * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20234949Sbapt * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21234949Sbapt * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22234949Sbapt * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23234949Sbapt * SUCH DAMAGE. 24234949Sbapt */ 25234949Sbapt 26234949Sbapt#include <sys/cdefs.h> 27234949Sbapt__FBSDID("$FreeBSD: head/sys/kern/tty_tty.c 179519 2008-06-03 12:38:00Z ed $"); 28234949Sbapt 29234949Sbapt#include <sys/param.h> 30234949Sbapt#include <sys/systm.h> 31234949Sbapt#include <sys/conf.h> 32234949Sbapt#include <sys/kernel.h> 33234949Sbapt#include <sys/proc.h> 34234949Sbapt#include <sys/sx.h> 35234949Sbapt#include <sys/vnode.h> 36234949Sbapt 37234949Sbapt#include <fs/devfs/devfs.h> 38234949Sbapt#include <fs/devfs/devfs_int.h> 39234949Sbapt 40234949Sbaptstatic d_open_t cttyopen; 41234949Sbapt 42234949Sbaptstatic struct cdevsw ctty_cdevsw = { 43234949Sbapt .d_version = D_VERSION, 44234949Sbapt .d_open = cttyopen, 45268899Sbapt .d_name = "ctty", 46234949Sbapt}; 47268899Sbapt 48234949Sbaptstatic struct cdev *ctty; 49234949Sbapt 50234949Sbaptstatic int 51234949Sbaptcttyopen(struct cdev *dev, int flag, int mode, struct thread *td) 52234949Sbapt{ 53234949Sbapt 54234949Sbapt return (ENXIO); 55234949Sbapt} 56234949Sbapt 57234949Sbaptstatic void 58234949Sbaptctty_clone(void *arg, struct ucred *cred, char *name, int namelen, 59234949Sbapt struct cdev **dev) 60234949Sbapt{ 61234949Sbapt 62234949Sbapt if (*dev != NULL) 63234949Sbapt return; 64234949Sbapt if (strcmp(name, "tty")) 65234949Sbapt return; 66234949Sbapt sx_sunlock(&clone_drain_lock); 67234949Sbapt sx_slock(&proctree_lock); 68234949Sbapt sx_slock(&clone_drain_lock); 69234949Sbapt dev_lock(); 70234949Sbapt if (!(curthread->td_proc->p_flag & P_CONTROLT)) 71234949Sbapt *dev = ctty; 72234949Sbapt else if (curthread->td_proc->p_session->s_ttyvp == NULL) 73234949Sbapt *dev = ctty; 74234949Sbapt else if (curthread->td_proc->p_session->s_ttyvp->v_type == VBAD || 75234949Sbapt curthread->td_proc->p_session->s_ttyvp->v_rdev == NULL) { 76234949Sbapt /* e.g. s_ttyvp was revoked */ 77234949Sbapt *dev = ctty; 78234949Sbapt } else 79234949Sbapt *dev = curthread->td_proc->p_session->s_ttyvp->v_rdev; 80234949Sbapt dev_refl(*dev); 81234949Sbapt dev_unlock(); 82234949Sbapt sx_sunlock(&proctree_lock); 83234949Sbapt} 84234949Sbapt 85234949Sbaptstatic void 86234949Sbaptctty_drvinit(void *unused) 87234949Sbapt{ 88234949Sbapt 89234949Sbapt EVENTHANDLER_REGISTER(dev_clone, ctty_clone, 0, 1000); 90234949Sbapt ctty = make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "ctty"); 91234949Sbapt} 92234949Sbapt 93234949SbaptSYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,ctty_drvinit,NULL); 94234949Sbapt