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v_rdev == NULL) { 76 /* e.g. s_ttyvp was revoked */ 77 *dev = ctty; 78 } else 79 *dev = p-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