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 1.27 1999/05/31 11:27:41 phk Exp $ 35 */ 36 37 /* 38 * Indirect driver for controlling tty. 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/conf.h> 44 #include <sys/lock.h> 45 #include <sys/proc.h> 46 #include <sys/ttycom.h> 47 #include <sys/vnode.h> 48 #include <sys/kernel.h> 49 50 static d_open_t cttyopen; 51 static d_read_t cttyread; 52 static d_write_t cttywrite; 53 static d_ioctl_t cttyioctl; 54 static d_poll_t cttypoll; 55 56 #define CDEV_MAJOR 1 57 /* Don't make this static, since fdesc_vnops uses it. */ 58 struct cdevsw ctty_cdevsw = { 59 /* open */ cttyopen, 60 /* close */ nullclose, 61 /* read */ cttyread, 62 /* write */ cttywrite, 63 /* ioctl */ cttyioctl, 64 /* stop */ nostop, 65 /* reset */ noreset, 66 /* devtotty */ nodevtotty, 67 /* poll */ cttypoll, 68 /* mmap */ nommap, 69 /* strategy */ nostrategy, 70 /* name */ "ctty", 71 /* parms */ noparms, 72 /* maj */ CDEV_MAJOR, 73 /* dump */ nodump, 74 /* psize */ nopsize, 75 /* flags */ D_TTY, 76 /* maxio */ 0, 77 /* bmaj */ -1 78 }; 79 80 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 81 82 /*ARGSUSED*/ 83 static int 84 cttyopen(dev, flag, mode, p) 85 dev_t dev; 86 int flag, mode; 87 struct proc *p; 88 { 89 struct vnode *ttyvp = cttyvp(p); 90 int error; 91 92 if (ttyvp == NULL) 93 return (ENXIO); 94 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 95 #ifdef PARANOID 96 /* 97 * Since group is tty and mode is 620 on most terminal lines 98 * and since sessions protect terminals from processes outside 99 * your session, this check is probably no longer necessary. 100 * Since it inhibits setuid root programs that later switch 101 * to another user from accessing /dev/tty, we have decided 102 * to delete this test. (mckusick 5/93) 103 */ 104 error = VOP_ACCESS(ttyvp, 105 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 106 if (!error) 107 #endif /* PARANOID */ 108 error = VOP_OPEN(ttyvp, flag, NOCRED, p); 109 VOP_UNLOCK(ttyvp, 0, p); 110 return (error); 111 } 112 113 /*ARGSUSED*/ 114 static int 115 cttyread(dev, uio, flag) 116 dev_t dev; 117 struct uio *uio; 118 int flag; 119 { 120 struct proc *p = uio->uio_procp; 121 register struct vnode *ttyvp = cttyvp(p); 122 int error; 123 124 if (ttyvp == NULL) 125 return (EIO); 126 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 127 error = VOP_READ(ttyvp, uio, flag, NOCRED); 128 VOP_UNLOCK(ttyvp, 0, p); 129 return (error); 130 } 131 132 /*ARGSUSED*/ 133 static int 134 cttywrite(dev, uio, flag) 135 dev_t dev; 136 struct uio *uio; 137 int flag; 138 { 139 struct proc *p = uio->uio_procp; 140 struct vnode *ttyvp = cttyvp(uio->uio_procp); 141 int error; 142 143 if (ttyvp == NULL) 144 return (EIO); 145 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 146 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 147 VOP_UNLOCK(ttyvp, 0, p); 148 return (error); 149 } 150 151 /*ARGSUSED*/ 152 static int 153 cttyioctl(dev, cmd, addr, flag, p) 154 dev_t dev; 155 u_long cmd; 156 caddr_t addr; 157 int flag; 158 struct proc *p; 159 { 160 struct vnode *ttyvp = cttyvp(p); 161 162 if (ttyvp == NULL) 163 return (EIO); 164 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */ 165 return EINVAL; /* to controlling tty -- infinite recursion */ 166 if (cmd == TIOCNOTTY) { 167 if (!SESS_LEADER(p)) { 168 p->p_flag &= ~P_CONTROLT; 169 return (0); 170 } else 171 return (EINVAL); 172 } 173 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p)); 174 } 175 176 /*ARGSUSED*/ 177 static int 178 cttypoll(dev, events, p) 179 dev_t dev; 180 int events; 181 struct proc *p; 182 { 183 struct vnode *ttyvp = cttyvp(p); 184 185 if (ttyvp == NULL) 186 /* try operation to get EOF/failure */ 187 return (seltrue(dev, events, p)); 188 return (VOP_POLL(ttyvp, events, p->p_ucred, p)); 189 } 190 191 static void ctty_drvinit __P((void *unused)); 192 static void 193 ctty_drvinit(unused) 194 void *unused; 195 { 196 197 make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "tty"); 198 } 199 200 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 201