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 1.24 1998/06/07 17:11:44 dfr 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 this static, since fdesc_vnops uses it. */ 63 struct cdevsw ctty_cdevsw = { 64 cttyopen, nullclose, cttyread, cttywrite, 65 cttyioctl, nullstop, nullreset, nodevtotty, 66 cttypoll, nommap, NULL, "ctty", 67 NULL, -1, nodump, nopsize, 68 D_TTY, 69 }; 70 71 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 72 73 /*ARGSUSED*/ 74 static int 75 cttyopen(dev, flag, mode, p) 76 dev_t dev; 77 int flag, mode; 78 struct proc *p; 79 { 80 struct vnode *ttyvp = cttyvp(p); 81 int error; 82 83 if (ttyvp == NULL) 84 return (ENXIO); 85 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 86 #ifdef PARANOID 87 /* 88 * Since group is tty and mode is 620 on most terminal lines 89 * and since sessions protect terminals from processes outside 90 * your session, this check is probably no longer necessary. 91 * Since it inhibits setuid root programs that later switch 92 * to another user from accessing /dev/tty, we have decided 93 * to delete this test. (mckusick 5/93) 94 */ 95 error = VOP_ACCESS(ttyvp, 96 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 97 if (!error) 98 #endif /* PARANOID */ 99 error = VOP_OPEN(ttyvp, flag, NOCRED, p); 100 VOP_UNLOCK(ttyvp, 0, p); 101 return (error); 102 } 103 104 /*ARGSUSED*/ 105 static int 106 cttyread(dev, uio, flag) 107 dev_t dev; 108 struct uio *uio; 109 int flag; 110 { 111 struct proc *p = uio->uio_procp; 112 register struct vnode *ttyvp = cttyvp(p); 113 int error; 114 115 if (ttyvp == NULL) 116 return (EIO); 117 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 118 error = VOP_READ(ttyvp, uio, flag, NOCRED); 119 VOP_UNLOCK(ttyvp, 0, p); 120 return (error); 121 } 122 123 /*ARGSUSED*/ 124 static int 125 cttywrite(dev, uio, flag) 126 dev_t dev; 127 struct uio *uio; 128 int flag; 129 { 130 struct proc *p = uio->uio_procp; 131 struct vnode *ttyvp = cttyvp(uio->uio_procp); 132 int error; 133 134 if (ttyvp == NULL) 135 return (EIO); 136 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 137 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 138 VOP_UNLOCK(ttyvp, 0, p); 139 return (error); 140 } 141 142 /*ARGSUSED*/ 143 static int 144 cttyioctl(dev, cmd, addr, flag, p) 145 dev_t dev; 146 u_long cmd; 147 caddr_t addr; 148 int flag; 149 struct proc *p; 150 { 151 struct vnode *ttyvp = cttyvp(p); 152 153 if (ttyvp == NULL) 154 return (EIO); 155 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */ 156 return EINVAL; /* to controlling tty -- infinite recursion */ 157 if (cmd == TIOCNOTTY) { 158 if (!SESS_LEADER(p)) { 159 p->p_flag &= ~P_CONTROLT; 160 return (0); 161 } else 162 return (EINVAL); 163 } 164 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p)); 165 } 166 167 /*ARGSUSED*/ 168 static int 169 cttypoll(dev, events, p) 170 dev_t dev; 171 int events; 172 struct proc *p; 173 { 174 struct vnode *ttyvp = cttyvp(p); 175 176 if (ttyvp == NULL) 177 /* try operation to get EOF/failure */ 178 return (seltrue(dev, events, p)); 179 return (VOP_POLL(ttyvp, events, p->p_ucred, p)); 180 } 181 182 static int ctty_devsw_installed; 183 #ifdef DEVFS 184 static void *ctty_devfs_token; 185 #endif 186 187 static void ctty_drvinit __P((void *unused)); 188 static void 189 ctty_drvinit(unused) 190 void *unused; 191 { 192 dev_t dev; 193 194 if( ! ctty_devsw_installed ) { 195 dev = makedev(CDEV_MAJOR,0); 196 cdevsw_add(&dev,&ctty_cdevsw,NULL); 197 ctty_devsw_installed = 1; 198 #ifdef DEVFS 199 ctty_devfs_token = 200 devfs_add_devswf(&ctty_cdevsw, 0, DV_CHR, 0, 0, 201 0666, "tty"); 202 #endif 203 } 204 } 205 206 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 207