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 1.10 1995/12/22 15:57:31 bde Exp $ 35 */ 36 37 /* 38 * Indirect driver for controlling tty. 39 */ 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/conf.h> 43 #include <sys/ioctl.h> 44 #include <sys/proc.h> 45 #include <sys/tty.h> 46 #include <sys/vnode.h> 47 #include <sys/file.h> 48 #include <sys/kernel.h> 49 #ifdef DEVFS 50 #include <sys/devfsext.h> 51 #endif /*DEVFS*/ 52 53 static d_open_t cttyopen; 54 static d_read_t cttyread; 55 static d_write_t cttywrite; 56 static d_ioctl_t cttyioctl; 57 static d_select_t cttyselect; 58 59 #define CDEV_MAJOR 1 60 /* Don't make static, fdesc_vnops uses this. */ 61 struct cdevsw ctty_cdevsw = 62 { cttyopen, nullclose, cttyread, cttywrite, /*1*/ 63 cttyioctl, nullstop, nullreset, nodevtotty,/* tty */ 64 cttyselect, nommap, NULL, "ctty", NULL, -1 }; 65 66 67 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 68 69 /*ARGSUSED*/ 70 static int 71 cttyopen(dev, flag, mode, p) 72 dev_t dev; 73 int flag, mode; 74 struct proc *p; 75 { 76 struct vnode *ttyvp = cttyvp(p); 77 int error; 78 79 if (ttyvp == NULL) 80 return (ENXIO); 81 VOP_LOCK(ttyvp); 82 #ifdef PARANOID 83 /* 84 * Since group is tty and mode is 620 on most terminal lines 85 * and since sessions protect terminals from processes outside 86 * your session, this check is probably no longer necessary. 87 * Since it inhibits setuid root programs that later switch 88 * to another user from accessing /dev/tty, we have decided 89 * to delete this test. (mckusick 5/93) 90 */ 91 error = VOP_ACCESS(ttyvp, 92 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 93 if (!error) 94 #endif /* PARANOID */ 95 error = VOP_OPEN(ttyvp, flag, NOCRED, p); 96 VOP_UNLOCK(ttyvp); 97 return (error); 98 } 99 100 /*ARGSUSED*/ 101 static int 102 cttyread(dev, uio, flag) 103 dev_t dev; 104 struct uio *uio; 105 int flag; 106 { 107 register struct vnode *ttyvp = cttyvp(uio->uio_procp); 108 int error; 109 110 if (ttyvp == NULL) 111 return (EIO); 112 VOP_LOCK(ttyvp); 113 error = VOP_READ(ttyvp, uio, flag, NOCRED); 114 VOP_UNLOCK(ttyvp); 115 return (error); 116 } 117 118 /*ARGSUSED*/ 119 static int 120 cttywrite(dev, uio, flag) 121 dev_t dev; 122 struct uio *uio; 123 int flag; 124 { 125 register struct vnode *ttyvp = cttyvp(uio->uio_procp); 126 int error; 127 128 if (ttyvp == NULL) 129 return (EIO); 130 VOP_LOCK(ttyvp); 131 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 132 VOP_UNLOCK(ttyvp); 133 return (error); 134 } 135 136 /*ARGSUSED*/ 137 static int 138 cttyioctl(dev, cmd, addr, flag, p) 139 dev_t dev; 140 int cmd; 141 caddr_t addr; 142 int flag; 143 struct proc *p; 144 { 145 struct vnode *ttyvp = cttyvp(p); 146 147 if (ttyvp == NULL) 148 return (EIO); 149 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */ 150 return EINVAL; /* to controlling tty -- infinite recursion */ 151 if (cmd == TIOCNOTTY) { 152 if (!SESS_LEADER(p)) { 153 p->p_flag &= ~P_CONTROLT; 154 return (0); 155 } else 156 return (EINVAL); 157 } 158 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p)); 159 } 160 161 /*ARGSUSED*/ 162 static int 163 cttyselect(dev, flag, p) 164 dev_t dev; 165 int flag; 166 struct proc *p; 167 { 168 struct vnode *ttyvp = cttyvp(p); 169 170 if (ttyvp == NULL) 171 return (1); /* try operation to get EOF/failure */ 172 return (VOP_SELECT(ttyvp, flag, FREAD|FWRITE, NOCRED, p)); 173 } 174 175 static ctty_devsw_installed = 0; 176 #ifdef DEVFS 177 static void *ctty_devfs_token; 178 #endif 179 180 static void 181 ctty_drvinit(void *unused) 182 { 183 dev_t dev; 184 185 if( ! ctty_devsw_installed ) { 186 dev = makedev(CDEV_MAJOR,0); 187 cdevsw_add(&dev,&ctty_cdevsw,NULL); 188 ctty_devsw_installed = 1; 189 #ifdef DEVFS 190 ctty_devfs_token = 191 devfs_add_devswf(&ctty_cdevsw, 0, DV_CHR, 0, 0, 192 0666, "tty"); 193 #endif 194 } 195 } 196 197 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 198 199 200