1 /* $NetBSD: tty_tty.c,v 1.26 2005/12/11 12:24:30 christos 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 1.26 2005/12/11 12:24:30 christos 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 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 51 52 /*ARGSUSED*/ 53 static int 54 cttyopen(dev_t dev, int flag, int mode, struct lwp *l) 55 { 56 struct vnode *ttyvp = cttyvp(l->l_proc); 57 int error; 58 59 if (ttyvp == NULL) 60 return (ENXIO); 61 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 62 #ifdef PARANOID 63 /* 64 * Since group is tty and mode is 620 on most terminal lines 65 * and since sessions protect terminals from processes outside 66 * your session, this check is probably no longer necessary. 67 * Since it inhibits setuid root programs that later switch 68 * to another user from accessing /dev/tty, we have decided 69 * to delete this test. (mckusick 5/93) 70 */ 71 error = VOP_ACCESS(ttyvp, 72 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p); 73 if (!error) 74 #endif /* PARANOID */ 75 error = VOP_OPEN(ttyvp, flag, NOCRED, l); 76 VOP_UNLOCK(ttyvp, 0); 77 return (error); 78 } 79 80 /*ARGSUSED*/ 81 static int 82 cttyread(dev_t dev, struct uio *uio, int flag) 83 { 84 struct vnode *ttyvp = cttyvp(uio->uio_lwp->l_proc); 85 int error; 86 87 if (ttyvp == NULL) 88 return (EIO); 89 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 90 error = VOP_READ(ttyvp, uio, flag, NOCRED); 91 VOP_UNLOCK(ttyvp, 0); 92 return (error); 93 } 94 95 /*ARGSUSED*/ 96 static int 97 cttywrite(dev_t dev, struct uio *uio, int flag) 98 { 99 struct vnode *ttyvp = cttyvp(uio->uio_lwp->l_proc); 100 struct mount *mp; 101 int error; 102 103 if (ttyvp == NULL) 104 return (EIO); 105 mp = NULL; 106 if (ttyvp->v_type != VCHR && 107 (error = vn_start_write(ttyvp, &mp, V_WAIT | V_PCATCH)) != 0) 108 return (error); 109 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 110 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 111 VOP_UNLOCK(ttyvp, 0); 112 vn_finished_write(mp, 0); 113 return (error); 114 } 115 116 /*ARGSUSED*/ 117 static int 118 cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct lwp *l) 119 { 120 struct vnode *ttyvp = cttyvp(l->l_proc); 121 122 if (ttyvp == NULL) 123 return (EIO); 124 if (cmd == TIOCSCTTY) /* XXX */ 125 return (EINVAL); 126 if (cmd == TIOCNOTTY) { 127 if (!SESS_LEADER(l->l_proc)) { 128 l->l_proc->p_flag &= ~P_CONTROLT; 129 return (0); 130 } else 131 return (EINVAL); 132 } 133 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, l)); 134 } 135 136 /*ARGSUSED*/ 137 static int 138 cttypoll(dev_t dev, int events, struct lwp *l) 139 { 140 struct vnode *ttyvp = cttyvp(l->l_proc); 141 142 if (ttyvp == NULL) 143 return (seltrue(dev, events, l)); 144 return (VOP_POLL(ttyvp, events, l)); 145 } 146 147 static int 148 cttykqfilter(dev_t dev, struct knote *kn) 149 { 150 /* This is called from filt_fileattach() by the attaching process. */ 151 struct proc *p = curproc; 152 struct vnode *ttyvp = cttyvp(p); 153 154 if (ttyvp == NULL) 155 return (1); 156 return (VOP_KQFILTER(ttyvp, kn)); 157 } 158 159 const struct cdevsw ctty_cdevsw = { 160 cttyopen, nullclose, cttyread, cttywrite, cttyioctl, 161 nullstop, notty, cttypoll, nommap, cttykqfilter, D_TTY 162 }; 163