1/*- 2 * Copyright (c) 2003 Poul-Henning Kamp. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26#include <sys/cdefs.h> 27__FBSDID("$FreeBSD: releng/11.0/sys/kern/tty_tty.c 285214 2015-07-06 18:53:56Z mjg $"); 28 29#include <sys/param.h> 30#include <sys/systm.h> 31#include <sys/conf.h> 32#include <sys/kernel.h> 33#include <sys/proc.h> 34#include <sys/sx.h> 35#include <sys/vnode.h> 36 37#include <fs/devfs/devfs.h> 38#include <fs/devfs/devfs_int.h> 39 40static d_open_t cttyopen; 41 42static struct cdevsw ctty_cdevsw = { 43 .d_version = D_VERSION, 44 .d_open = cttyopen, 45 .d_name = "ctty", 46}; 47 48static struct cdev *ctty; 49 50static int 51cttyopen(struct cdev *dev, int flag, int mode, struct thread *td) 52{ 53 54 return (ENXIO); 55} 56 57static void 58ctty_clone(void *arg, struct ucred *cred, char *name, int namelen, 59 struct cdev **dev) 60{ 61 struct proc *p; 62 63 if (*dev != NULL) 64 return; 65 if (strcmp(name, "tty")) 66 return; 67 p = curproc; 68 sx_sunlock(&clone_drain_lock); 69 sx_slock(&proctree_lock); 70 sx_slock(&clone_drain_lock); 71 dev_lock(); 72 if (!(p->p_flag & P_CONTROLT)) 73 *dev = ctty; 74 else if (p->p_session->s_ttyvp == NULL) 75 *dev = ctty; 76 else if (p->p_session->s_ttyvp->v_type == VBAD || 77 p->p_session->s_ttyvp->v_rdev == NULL) { 78 /* e.g. s_ttyvp was revoked */ 79 *dev = ctty; 80 } else 81 *dev = p->p_session->s_ttyvp->v_rdev; 82 dev_refl(*dev); 83 dev_unlock(); 84 sx_sunlock(&proctree_lock); 85} 86 87static void 88ctty_drvinit(void *unused) 89{ 90 91 EVENTHANDLER_REGISTER(dev_clone, ctty_clone, 0, 1000); 92 ctty = make_dev_credf(MAKEDEV_ETERNAL, &ctty_cdevsw, 0, NULL, UID_ROOT, 93 GID_WHEEL, 0666, "ctty"); 94} 95 96SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,ctty_drvinit,NULL); 97