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("$FreeBSD$"); 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/vnode.h> 35 36 static d_open_t cttyopen; 37 38 static struct cdevsw ctty_cdevsw = { 39 .d_version = D_VERSION, 40 .d_open = cttyopen, 41 .d_name = "ctty", 42 .d_flags = D_TTY | D_NEEDGIANT, 43 }; 44 45 static struct cdev *ctty; 46 47 static int 48 cttyopen(struct cdev *dev, int flag, int mode, struct thread *td) 49 { 50 51 return (ENXIO); 52 } 53 54 static void 55 ctty_clone(void *arg, struct ucred *cred, char *name, int namelen, 56 struct cdev **dev) 57 { 58 59 if (*dev != NULL) 60 return; 61 if (strcmp(name, "tty")) 62 return; 63 if (!(curthread->td_proc->p_flag & P_CONTROLT)) 64 *dev = ctty; 65 else if (curthread->td_proc->p_session->s_ttyvp == NULL) 66 *dev = ctty; 67 else if (curthread->td_proc->p_session->s_ttyvp->v_type == VBAD || 68 curthread->td_proc->p_session->s_ttyvp->v_rdev == NULL) { 69 /* e.g. s_ttyvp was revoked */ 70 *dev = ctty; 71 } else 72 *dev = curthread->td_proc->p_session->s_ttyvp->v_rdev; 73 dev_ref(*dev); 74 } 75 76 static void 77 ctty_drvinit(void *unused) 78 { 79 80 EVENTHANDLER_REGISTER(dev_clone, ctty_clone, 0, 1000); 81 ctty = make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "ctty"); 82 } 83 84 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,ctty_drvinit,NULL) 85