1 /* $NetBSD: tty_tty.c,v 1.23 2003/10/15 11:29:00 hannken Exp $ */ 2 3 /*- 4 * Copyright (c) 1982, 1986, 1991, 1993, 1995 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)tty_tty.c 8.2 (Berkeley) 9/23/93 32 */ 33 34 /* 35 * Indirect driver for controlling tty. 36 */ 37 38 #include <sys/cdefs.h> 39 __KERNEL_RCSID(0, "$NetBSD: tty_tty.c,v 1.23 2003/10/15 11:29:00 hannken Exp $"); 40 41 #include <sys/param.h> 42 #include <sys/systm.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/conf.h> 49 50 51 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 52 53 dev_type_open(cttyopen); 54 dev_type_read(cttyread); 55 dev_type_write(cttywrite); 56 dev_type_ioctl(cttyioctl); 57 dev_type_poll(cttypoll); 58 dev_type_kqfilter(cttykqfilter); 59 60 const struct cdevsw ctty_cdevsw = { 61 cttyopen, nullclose, cttyread, cttywrite, cttyioctl, 62 nullstop, notty, cttypoll, nommap, cttykqfilter, D_TTY 63 }; 64 65 /*ARGSUSED*/ 66 int 67 cttyopen(dev, flag, mode, p) 68 dev_t dev; 69 int flag, mode; 70 struct proc *p; 71 { 72 struct vnode *ttyvp = cttyvp(p); 73 int error; 74 75 if (ttyvp == NULL) 76 return (ENXIO); 77 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 78 #ifdef PARANOID 79 /* 80 * Since group is tty and mode is 620 on most terminal lines 81 * and since sessions protect terminals from processes outside 82 * your session, this check is probably no longer necessary. 83 * Since it inhibits setuid root programs that later switch 84 * to another user from accessing /dev/tty, we have decided 85 * to delete this test. (mckusick 5/93) 86 */ 87 error = VOP_ACCESS(ttyvp, 88 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 89 if (!error) 90 #endif /* PARANOID */ 91 error = VOP_OPEN(ttyvp, flag, NOCRED, p); 92 VOP_UNLOCK(ttyvp, 0); 93 return (error); 94 } 95 96 /*ARGSUSED*/ 97 int 98 cttyread(dev, uio, flag) 99 dev_t dev; 100 struct uio *uio; 101 int flag; 102 { 103 struct vnode *ttyvp = cttyvp(uio->uio_procp); 104 int error; 105 106 if (ttyvp == NULL) 107 return (EIO); 108 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 109 error = VOP_READ(ttyvp, uio, flag, NOCRED); 110 VOP_UNLOCK(ttyvp, 0); 111 return (error); 112 } 113 114 /*ARGSUSED*/ 115 int 116 cttywrite(dev, uio, flag) 117 dev_t dev; 118 struct uio *uio; 119 int flag; 120 { 121 struct vnode *ttyvp = cttyvp(uio->uio_procp); 122 struct mount *mp; 123 int error; 124 125 if (ttyvp == NULL) 126 return (EIO); 127 mp = NULL; 128 if (ttyvp->v_type != VCHR && 129 (error = vn_start_write(ttyvp, &mp, V_WAIT | V_PCATCH)) != 0) 130 return (error); 131 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 132 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 133 VOP_UNLOCK(ttyvp, 0); 134 vn_finished_write(mp, 0); 135 return (error); 136 } 137 138 /*ARGSUSED*/ 139 int 140 cttyioctl(dev, cmd, addr, flag, p) 141 dev_t dev; 142 u_long cmd; 143 caddr_t addr; 144 int flag; 145 struct proc *p; 146 { 147 struct vnode *ttyvp = cttyvp(p); 148 149 if (ttyvp == NULL) 150 return (EIO); 151 if (cmd == TIOCSCTTY) /* XXX */ 152 return (EINVAL); 153 if (cmd == TIOCNOTTY) { 154 if (!SESS_LEADER(p)) { 155 p->p_flag &= ~P_CONTROLT; 156 return (0); 157 } else 158 return (EINVAL); 159 } 160 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p)); 161 } 162 163 /*ARGSUSED*/ 164 int 165 cttypoll(dev, events, p) 166 dev_t dev; 167 int events; 168 struct proc *p; 169 { 170 struct vnode *ttyvp = cttyvp(p); 171 172 if (ttyvp == NULL) 173 return (seltrue(dev, events, p)); 174 return (VOP_POLL(ttyvp, events, p)); 175 } 176 177 int 178 cttykqfilter(dev, kn) 179 dev_t dev; 180 struct knote *kn; 181 { 182 /* This is called from filt_fileattach() by the attaching process. */ 183 struct proc *p = curproc; 184 struct vnode *ttyvp = cttyvp(p); 185 186 if (ttyvp == NULL) 187 return (1); 188 return (VOP_KQFILTER(ttyvp, kn)); 189 } 190