1 /*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tty_tty.c 8.2 (Berkeley) 9/23/93 34 * $Id: tty_tty.c,v 1.23 1998/02/20 13:46:56 bde Exp $ 35 */ 36 37 /* 38 * Indirect driver for controlling tty. 39 */ 40 41 #include "opt_devfs.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/conf.h> 46 #include <sys/lock.h> 47 #include <sys/proc.h> 48 #include <sys/ttycom.h> 49 #include <sys/vnode.h> 50 #include <sys/kernel.h> 51 #ifdef DEVFS 52 #include <sys/devfsext.h> 53 #endif /*DEVFS*/ 54 55 static d_open_t cttyopen; 56 static d_read_t cttyread; 57 static d_write_t cttywrite; 58 static d_ioctl_t cttyioctl; 59 static d_poll_t cttypoll; 60 61 #define CDEV_MAJOR 1 62 /* Don't make static, fdesc_vnops uses this. */ 63 struct cdevsw ctty_cdevsw = 64 { cttyopen, nullclose, cttyread, cttywrite, /*1*/ 65 cttyioctl, nullstop, nullreset, nodevtotty,/* tty */ 66 cttypoll, nommap, NULL, "ctty", NULL, -1 }; 67 68 69 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 70 71 /*ARGSUSED*/ 72 static int 73 cttyopen(dev, flag, mode, p) 74 dev_t dev; 75 int flag, mode; 76 struct proc *p; 77 { 78 struct vnode *ttyvp = cttyvp(p); 79 int error; 80 81 if (ttyvp == NULL) 82 return (ENXIO); 83 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 84 #ifdef PARANOID 85 /* 86 * Since group is tty and mode is 620 on most terminal lines 87 * and since sessions protect terminals from processes outside 88 * your session, this check is probably no longer necessary. 89 * Since it inhibits setuid root programs that later switch 90 * to another user from accessing /dev/tty, we have decided 91 * to delete this test. (mckusick 5/93) 92 */ 93 error = VOP_ACCESS(ttyvp, 94 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 95 if (!error) 96 #endif /* PARANOID */ 97 error = VOP_OPEN(ttyvp, flag, NOCRED, p); 98 VOP_UNLOCK(ttyvp, 0, p); 99 return (error); 100 } 101 102 /*ARGSUSED*/ 103 static int 104 cttyread(dev, uio, flag) 105 dev_t dev; 106 struct uio *uio; 107 int flag; 108 { 109 struct proc *p = uio->uio_procp; 110 register struct vnode *ttyvp = cttyvp(p); 111 int error; 112 113 if (ttyvp == NULL) 114 return (EIO); 115 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 116 error = VOP_READ(ttyvp, uio, flag, NOCRED); 117 VOP_UNLOCK(ttyvp, 0, p); 118 return (error); 119 } 120 121 /*ARGSUSED*/ 122 static int 123 cttywrite(dev, uio, flag) 124 dev_t dev; 125 struct uio *uio; 126 int flag; 127 { 128 struct proc *p = uio->uio_procp; 129 struct vnode *ttyvp = cttyvp(uio->uio_procp); 130 int error; 131 132 if (ttyvp == NULL) 133 return (EIO); 134 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 135 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 136 VOP_UNLOCK(ttyvp, 0, p); 137 return (error); 138 } 139 140 /*ARGSUSED*/ 141 static int 142 cttyioctl(dev, cmd, addr, flag, p) 143 dev_t dev; 144 u_long cmd; 145 caddr_t addr; 146 int flag; 147 struct proc *p; 148 { 149 struct vnode *ttyvp = cttyvp(p); 150 151 if (ttyvp == NULL) 152 return (EIO); 153 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */ 154 return EINVAL; /* to controlling tty -- infinite recursion */ 155 if (cmd == TIOCNOTTY) { 156 if (!SESS_LEADER(p)) { 157 p->p_flag &= ~P_CONTROLT; 158 return (0); 159 } else 160 return (EINVAL); 161 } 162 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p)); 163 } 164 165 /*ARGSUSED*/ 166 static int 167 cttypoll(dev, events, p) 168 dev_t dev; 169 int events; 170 struct proc *p; 171 { 172 struct vnode *ttyvp = cttyvp(p); 173 174 if (ttyvp == NULL) 175 /* try operation to get EOF/failure */ 176 return (seltrue(dev, events, p)); 177 return (VOP_POLL(ttyvp, events, p->p_ucred, p)); 178 } 179 180 static int ctty_devsw_installed; 181 #ifdef DEVFS 182 static void *ctty_devfs_token; 183 #endif 184 185 static void ctty_drvinit __P((void *unused)); 186 static void 187 ctty_drvinit(unused) 188 void *unused; 189 { 190 dev_t dev; 191 192 if( ! ctty_devsw_installed ) { 193 dev = makedev(CDEV_MAJOR,0); 194 cdevsw_add(&dev,&ctty_cdevsw,NULL); 195 ctty_devsw_installed = 1; 196 #ifdef DEVFS 197 ctty_devfs_token = 198 devfs_add_devswf(&ctty_cdevsw, 0, DV_CHR, 0, 0, 199 0666, "tty"); 200 #endif 201 } 202 } 203 204 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 205