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