1 /* $NetBSD: tty_tty.c,v 1.28 2006/05/14 21:15:11 elad 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 1.28 2006/05/14 21:15:11 elad 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 #include <sys/kauth.h> 50 51 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 52 53 /*ARGSUSED*/ 54 static int 55 cttyopen(dev_t dev, int flag, int mode, struct lwp *l) 56 { 57 struct vnode *ttyvp = cttyvp(l->l_proc); 58 int error; 59 60 if (ttyvp == NULL) 61 return (ENXIO); 62 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 63 #ifdef PARANOID 64 /* 65 * Since group is tty and mode is 620 on most terminal lines 66 * and since sessions protect terminals from processes outside 67 * your session, this check is probably no longer necessary. 68 * Since it inhibits setuid root programs that later switch 69 * to another user from accessing /dev/tty, we have decided 70 * to delete this test. (mckusick 5/93) 71 */ 72 error = VOP_ACCESS(ttyvp, 73 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_cred, p); 74 if (!error) 75 #endif /* PARANOID */ 76 error = VOP_OPEN(ttyvp, flag, NOCRED, l); 77 VOP_UNLOCK(ttyvp, 0); 78 return (error); 79 } 80 81 /*ARGSUSED*/ 82 static int 83 cttyread(dev_t dev, struct uio *uio, int flag) 84 { 85 struct vnode *ttyvp = cttyvp(curproc); 86 int error; 87 88 if (ttyvp == NULL) 89 return (EIO); 90 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 91 error = VOP_READ(ttyvp, uio, flag, NOCRED); 92 VOP_UNLOCK(ttyvp, 0); 93 return (error); 94 } 95 96 /*ARGSUSED*/ 97 static int 98 cttywrite(dev_t dev, struct uio *uio, int flag) 99 { 100 struct vnode *ttyvp = cttyvp(curproc); 101 struct mount *mp; 102 int error; 103 104 if (ttyvp == NULL) 105 return (EIO); 106 mp = NULL; 107 if (ttyvp->v_type != VCHR && 108 (error = vn_start_write(ttyvp, &mp, V_WAIT | V_PCATCH)) != 0) 109 return (error); 110 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 111 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 112 VOP_UNLOCK(ttyvp, 0); 113 vn_finished_write(mp, 0); 114 return (error); 115 } 116 117 /*ARGSUSED*/ 118 static int 119 cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct lwp *l) 120 { 121 struct vnode *ttyvp = cttyvp(l->l_proc); 122 123 if (ttyvp == NULL) 124 return (EIO); 125 if (cmd == TIOCSCTTY) /* XXX */ 126 return (EINVAL); 127 if (cmd == TIOCNOTTY) { 128 if (!SESS_LEADER(l->l_proc)) { 129 l->l_proc->p_flag &= ~P_CONTROLT; 130 return (0); 131 } else 132 return (EINVAL); 133 } 134 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, l)); 135 } 136 137 /*ARGSUSED*/ 138 static int 139 cttypoll(dev_t dev, int events, struct lwp *l) 140 { 141 struct vnode *ttyvp = cttyvp(l->l_proc); 142 143 if (ttyvp == NULL) 144 return (seltrue(dev, events, l)); 145 return (VOP_POLL(ttyvp, events, l)); 146 } 147 148 static int 149 cttykqfilter(dev_t dev, struct knote *kn) 150 { 151 /* This is called from filt_fileattach() by the attaching process. */ 152 struct proc *p = curproc; 153 struct vnode *ttyvp = cttyvp(p); 154 155 if (ttyvp == NULL) 156 return (1); 157 return (VOP_KQFILTER(ttyvp, kn)); 158 } 159 160 const struct cdevsw ctty_cdevsw = { 161 cttyopen, nullclose, cttyread, cttywrite, cttyioctl, 162 nullstop, notty, cttypoll, nommap, cttykqfilter, D_TTY 163 }; 164