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 1.6 2003/08/26 21:09:02 rob 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 /* name */ "ctty", 61 /* maj */ CDEV_MAJOR, 62 /* flags */ D_TTY, 63 /* port */ NULL, 64 /* autoq */ 0, 65 66 /* open */ cttyopen, 67 /* close */ nullclose, 68 /* read */ cttyread, 69 /* write */ cttywrite, 70 /* ioctl */ cttyioctl, 71 /* poll */ cttypoll, 72 /* mmap */ nommap, 73 /* strategy */ nostrategy, 74 /* dump */ nodump, 75 /* psize */ nopsize 76 }; 77 78 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 79 80 /*ARGSUSED*/ 81 static int 82 cttyopen(dev_t dev, int flag, int mode, struct thread *td) 83 { 84 struct proc *p = td->td_proc; 85 struct vnode *ttyvp; 86 int error; 87 88 KKASSERT(p); 89 ttyvp = cttyvp(p); 90 91 if (ttyvp == NULL) 92 return (ENXIO); 93 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, td); 94 #ifdef PARANOID 95 /* 96 * Since group is tty and mode is 620 on most terminal lines 97 * and since sessions protect terminals from processes outside 98 * your session, this check is probably no longer necessary. 99 * Since it inhibits setuid root programs that later switch 100 * to another user from accessing /dev/tty, we have decided 101 * to delete this test. (mckusick 5/93) 102 */ 103 error = VOP_ACCESS(ttyvp, 104 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, td); 105 if (!error) 106 #endif /* PARANOID */ 107 error = VOP_OPEN(ttyvp, flag, NOCRED, td); 108 VOP_UNLOCK(ttyvp, 0, td); 109 return (error); 110 } 111 112 /*ARGSUSED*/ 113 static int 114 cttyread(dev, uio, flag) 115 dev_t dev; 116 struct uio *uio; 117 int flag; 118 { 119 struct thread *td = uio->uio_td; 120 struct proc *p = td->td_proc; 121 struct vnode *ttyvp; 122 int error; 123 124 KKASSERT(p); 125 ttyvp = cttyvp(p); 126 if (ttyvp == NULL) 127 return (EIO); 128 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, td); 129 error = VOP_READ(ttyvp, uio, flag, NOCRED); 130 VOP_UNLOCK(ttyvp, 0, td); 131 return (error); 132 } 133 134 /*ARGSUSED*/ 135 static int 136 cttywrite(dev, uio, flag) 137 dev_t dev; 138 struct uio *uio; 139 int flag; 140 { 141 struct thread *td = uio->uio_td; 142 struct proc *p = td->td_proc; 143 struct vnode *ttyvp; 144 int error; 145 146 KKASSERT(p); 147 ttyvp = cttyvp(p); 148 if (ttyvp == NULL) 149 return (EIO); 150 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, td); 151 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 152 VOP_UNLOCK(ttyvp, 0, td); 153 return (error); 154 } 155 156 /*ARGSUSED*/ 157 static int 158 cttyioctl(dev, cmd, addr, flag, td) 159 dev_t dev; 160 u_long cmd; 161 caddr_t addr; 162 int flag; 163 struct thread *td; 164 { 165 struct vnode *ttyvp; 166 struct proc *p = td->td_proc; 167 168 KKASSERT(p); 169 ttyvp = cttyvp(p); 170 if (ttyvp == NULL) 171 return (EIO); 172 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */ 173 return EINVAL; /* to controlling tty -- infinite recursion */ 174 if (cmd == TIOCNOTTY) { 175 if (!SESS_LEADER(p)) { 176 p->p_flag &= ~P_CONTROLT; 177 return (0); 178 } else 179 return (EINVAL); 180 } 181 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, td)); 182 } 183 184 /*ARGSUSED*/ 185 static int 186 cttypoll(dev_t dev, int events, struct thread *td) 187 { 188 struct vnode *ttyvp; 189 struct proc *p = td->td_proc; 190 191 KKASSERT(p); 192 ttyvp = cttyvp(p); 193 if (ttyvp == NULL) 194 /* try operation to get EOF/failure */ 195 return (seltrue(dev, events, td)); 196 return (VOP_POLL(ttyvp, events, p->p_ucred, td)); 197 } 198 199 static void ctty_drvinit (void *unused); 200 static void 201 ctty_drvinit(unused) 202 void *unused; 203 { 204 205 make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "tty"); 206 } 207 208 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 209