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 * $FreeBSD: src/sys/kern/tty_tty.c,v 1.30 1999/09/25 18:24:24 phk Exp $ 35 * $DragonFly: src/sys/kern/tty_tty.c,v 1.2 2003/06/17 04:28:41 dillon Exp $ 36 */ 37 38 /* 39 * Indirect driver for controlling tty. 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/conf.h> 45 #include <sys/lock.h> 46 #include <sys/proc.h> 47 #include <sys/ttycom.h> 48 #include <sys/vnode.h> 49 #include <sys/kernel.h> 50 51 static d_open_t cttyopen; 52 static d_read_t cttyread; 53 static d_write_t cttywrite; 54 static d_ioctl_t cttyioctl; 55 static d_poll_t cttypoll; 56 57 #define CDEV_MAJOR 1 58 /* Don't make this static, since fdesc_vnops uses it. */ 59 struct cdevsw ctty_cdevsw = { 60 /* open */ cttyopen, 61 /* close */ nullclose, 62 /* read */ cttyread, 63 /* write */ cttywrite, 64 /* ioctl */ cttyioctl, 65 /* poll */ cttypoll, 66 /* mmap */ nommap, 67 /* strategy */ nostrategy, 68 /* name */ "ctty", 69 /* maj */ CDEV_MAJOR, 70 /* dump */ nodump, 71 /* psize */ nopsize, 72 /* flags */ D_TTY, 73 /* bmaj */ -1 74 }; 75 76 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 77 78 /*ARGSUSED*/ 79 static int 80 cttyopen(dev, flag, mode, p) 81 dev_t dev; 82 int flag, mode; 83 struct proc *p; 84 { 85 struct vnode *ttyvp = cttyvp(p); 86 int error; 87 88 if (ttyvp == NULL) 89 return (ENXIO); 90 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 91 #ifdef PARANOID 92 /* 93 * Since group is tty and mode is 620 on most terminal lines 94 * and since sessions protect terminals from processes outside 95 * your session, this check is probably no longer necessary. 96 * Since it inhibits setuid root programs that later switch 97 * to another user from accessing /dev/tty, we have decided 98 * to delete this test. (mckusick 5/93) 99 */ 100 error = VOP_ACCESS(ttyvp, 101 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 102 if (!error) 103 #endif /* PARANOID */ 104 error = VOP_OPEN(ttyvp, flag, NOCRED, p); 105 VOP_UNLOCK(ttyvp, 0, p); 106 return (error); 107 } 108 109 /*ARGSUSED*/ 110 static int 111 cttyread(dev, uio, flag) 112 dev_t dev; 113 struct uio *uio; 114 int flag; 115 { 116 struct proc *p = uio->uio_procp; 117 register struct vnode *ttyvp = cttyvp(p); 118 int error; 119 120 if (ttyvp == NULL) 121 return (EIO); 122 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 123 error = VOP_READ(ttyvp, uio, flag, NOCRED); 124 VOP_UNLOCK(ttyvp, 0, p); 125 return (error); 126 } 127 128 /*ARGSUSED*/ 129 static int 130 cttywrite(dev, uio, flag) 131 dev_t dev; 132 struct uio *uio; 133 int flag; 134 { 135 struct proc *p = uio->uio_procp; 136 struct vnode *ttyvp = cttyvp(uio->uio_procp); 137 int error; 138 139 if (ttyvp == NULL) 140 return (EIO); 141 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p); 142 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 143 VOP_UNLOCK(ttyvp, 0, p); 144 return (error); 145 } 146 147 /*ARGSUSED*/ 148 static int 149 cttyioctl(dev, cmd, addr, flag, p) 150 dev_t dev; 151 u_long cmd; 152 caddr_t addr; 153 int flag; 154 struct proc *p; 155 { 156 struct vnode *ttyvp = cttyvp(p); 157 158 if (ttyvp == NULL) 159 return (EIO); 160 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */ 161 return EINVAL; /* to controlling tty -- infinite recursion */ 162 if (cmd == TIOCNOTTY) { 163 if (!SESS_LEADER(p)) { 164 p->p_flag &= ~P_CONTROLT; 165 return (0); 166 } else 167 return (EINVAL); 168 } 169 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p)); 170 } 171 172 /*ARGSUSED*/ 173 static int 174 cttypoll(dev, events, p) 175 dev_t dev; 176 int events; 177 struct proc *p; 178 { 179 struct vnode *ttyvp = cttyvp(p); 180 181 if (ttyvp == NULL) 182 /* try operation to get EOF/failure */ 183 return (seltrue(dev, events, p)); 184 return (VOP_POLL(ttyvp, events, p->p_ucred, p)); 185 } 186 187 static void ctty_drvinit __P((void *unused)); 188 static void 189 ctty_drvinit(unused) 190 void *unused; 191 { 192 193 make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "tty"); 194 } 195 196 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 197