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/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 .d_flags = D_TTY | D_NEEDGIANT, 47 }; 48 49 static struct cdev *ctty; 50 51 static int 52 cttyopen(struct cdev *dev, int flag, int mode, struct thread *td) 53 { 54 55 return (ENXIO); 56 } 57 58 static void 59 ctty_clone(void *arg, struct ucred *cred, char *name, int namelen, 60 struct cdev **dev) 61 { 62 63 if (*dev != NULL) 64 return; 65 if (strcmp(name, "tty")) 66 return; 67 sx_sunlock(&clone_drain_lock); 68 mtx_lock(&Giant); 69 sx_slock(&proctree_lock); 70 sx_slock(&clone_drain_lock); 71 dev_lock(); 72 if (!(curthread->td_proc->p_flag & P_CONTROLT)) 73 *dev = ctty; 74 else if (curthread->td_proc->p_session->s_ttyvp == NULL) 75 *dev = ctty; 76 else if (curthread->td_proc->p_session->s_ttyvp->v_type == VBAD || 77 curthread->td_proc->p_session->s_ttyvp->v_rdev == NULL) { 78 /* e.g. s_ttyvp was revoked */ 79 *dev = ctty; 80 } else 81 *dev = curthread->td_proc->p_session->s_ttyvp->v_rdev; 82 dev_refl(*dev); 83 dev_unlock(); 84 sx_sunlock(&proctree_lock); 85 mtx_unlock(&Giant); 86 } 87 88 static void 89 ctty_drvinit(void *unused) 90 { 91 92 EVENTHANDLER_REGISTER(dev_clone, ctty_clone, 0, 1000); 93 ctty = make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "ctty"); 94 } 95 96 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,ctty_drvinit,NULL) 97