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 1.18 1997/09/14 02:40:46 peter Exp $ 35 */ 36 37 /* 38 * Indirect driver for controlling tty. 39 */ 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/conf.h> 43 #include <sys/proc.h> 44 #include <sys/tty.h> 45 #include <sys/vnode.h> 46 #include <sys/fcntl.h> 47 #include <sys/kernel.h> 48 #ifdef DEVFS 49 #include <sys/devfsext.h> 50 #endif /*DEVFS*/ 51 52 static d_open_t cttyopen; 53 static d_read_t cttyread; 54 static d_write_t cttywrite; 55 static d_ioctl_t cttyioctl; 56 static d_poll_t cttypoll; 57 58 #define CDEV_MAJOR 1 59 /* Don't make static, fdesc_vnops uses this. */ 60 struct cdevsw ctty_cdevsw = 61 { cttyopen, nullclose, cttyread, cttywrite, /*1*/ 62 cttyioctl, nullstop, nullreset, nodevtotty,/* tty */ 63 cttypoll, nommap, NULL, "ctty", NULL, -1 }; 64 65 66 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 67 68 /*ARGSUSED*/ 69 static int 70 cttyopen(dev, flag, mode, p) 71 dev_t dev; 72 int flag, mode; 73 struct proc *p; 74 { 75 struct vnode *ttyvp = cttyvp(p); 76 int error; 77 78 if (ttyvp == NULL) 79 return (ENXIO); 80 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 81 #ifdef PARANOID 82 /* 83 * Since group is tty and mode is 620 on most terminal lines 84 * and since sessions protect terminals from processes outside 85 * your session, this check is probably no longer necessary. 86 * Since it inhibits setuid root programs that later switch 87 * to another user from accessing /dev/tty, we have decided 88 * to delete this test. (mckusick 5/93) 89 */ 90 error = VOP_ACCESS(ttyvp, 91 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 92 if (!error) 93 #endif /* PARANOID */ 94 error = VOP_OPEN(ttyvp, flag, NOCRED, p); 95 VOP_UNLOCK(ttyvp, 0, p); 96 return (error); 97 } 98 99 /*ARGSUSED*/ 100 static int 101 cttyread(dev, uio, flag) 102 dev_t dev; 103 struct uio *uio; 104 int flag; 105 { 106 struct proc *p = uio->uio_procp; 107 register struct vnode *ttyvp = cttyvp(p); 108 int error; 109 110 if (ttyvp == NULL) 111 return (EIO); 112 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 113 error = VOP_READ(ttyvp, uio, flag, NOCRED); 114 VOP_UNLOCK(ttyvp, 0, p); 115 return (error); 116 } 117 118 /*ARGSUSED*/ 119 static int 120 cttywrite(dev, uio, flag) 121 dev_t dev; 122 struct uio *uio; 123 int flag; 124 { 125 struct proc *p = uio->uio_procp; 126 struct vnode *ttyvp = cttyvp(uio->uio_procp); 127 int error; 128 129 if (ttyvp == NULL) 130 return (EIO); 131 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 132 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 133 VOP_UNLOCK(ttyvp, 0, p); 134 return (error); 135 } 136 137 /*ARGSUSED*/ 138 static int 139 cttyioctl(dev, cmd, addr, flag, p) 140 dev_t dev; 141 int cmd; 142 caddr_t addr; 143 int flag; 144 struct proc *p; 145 { 146 struct vnode *ttyvp = cttyvp(p); 147 148 if (ttyvp == NULL) 149 return (EIO); 150 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */ 151 return EINVAL; /* to controlling tty -- infinite recursion */ 152 if (cmd == TIOCNOTTY) { 153 if (!SESS_LEADER(p)) { 154 p->p_flag &= ~P_CONTROLT; 155 return (0); 156 } else 157 return (EINVAL); 158 } 159 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p)); 160 } 161 162 /*ARGSUSED*/ 163 static int 164 cttypoll(dev, events, p) 165 dev_t dev; 166 int events; 167 struct proc *p; 168 { 169 struct vnode *ttyvp = cttyvp(p); 170 171 if (ttyvp == NULL) 172 /* try operation to get EOF/failure */ 173 return (seltrue(dev, events, p)); 174 return (VOP_POLL(ttyvp, events, p->p_ucred, p)); 175 } 176 177 static ctty_devsw_installed = 0; 178 #ifdef DEVFS 179 static void *ctty_devfs_token; 180 #endif 181 182 static void ctty_drvinit __P((void *unused)); 183 static void 184 ctty_drvinit(unused) 185 void *unused; 186 { 187 dev_t dev; 188 189 if( ! ctty_devsw_installed ) { 190 dev = makedev(CDEV_MAJOR,0); 191 cdevsw_add(&dev,&ctty_cdevsw,NULL); 192 ctty_devsw_installed = 1; 193 #ifdef DEVFS 194 ctty_devfs_token = 195 devfs_add_devswf(&ctty_cdevsw, 0, DV_CHR, 0, 0, 196 0666, "tty"); 197 #endif 198 } 199 } 200 201 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 202