1 /* $NetBSD: tty_tty.c,v 1.38 2010/06/24 13:03:11 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 1.38 2010/06/24 13:03:11 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 #include <sys/kauth.h> 50 51 /* XXXSMP */ 52 #define cttyvp(p) ((p)->p_lflag & PL_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 53 54 /*ARGSUSED*/ 55 static int 56 cttyopen(dev_t dev, int flag, int mode, struct lwp *l) 57 { 58 struct vnode *ttyvp = cttyvp(l->l_proc); 59 int error; 60 61 if (ttyvp == NULL) 62 return (ENXIO); 63 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 64 #ifdef PARANOID 65 /* 66 * Since group is tty and mode is 620 on most terminal lines 67 * and since sessions protect terminals from processes outside 68 * your session, this check is probably no longer necessary. 69 * Since it inhibits setuid root programs that later switch 70 * to another user from accessing /dev/tty, we have decided 71 * to delete this test. (mckusick 5/93) 72 */ 73 error = VOP_ACCESS(ttyvp, 74 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), l->l_cred, l); 75 if (!error) 76 #endif /* PARANOID */ 77 error = VOP_OPEN(ttyvp, flag, NOCRED); 78 VOP_UNLOCK(ttyvp); 79 return (error); 80 } 81 82 /*ARGSUSED*/ 83 static int 84 cttyread(dev_t dev, struct uio *uio, int flag) 85 { 86 struct vnode *ttyvp = cttyvp(curproc); 87 int error; 88 89 if (ttyvp == NULL) 90 return (EIO); 91 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 92 error = VOP_READ(ttyvp, uio, flag, NOCRED); 93 VOP_UNLOCK(ttyvp); 94 return (error); 95 } 96 97 /*ARGSUSED*/ 98 static int 99 cttywrite(dev_t dev, struct uio *uio, int flag) 100 { 101 struct vnode *ttyvp = cttyvp(curproc); 102 int error; 103 104 if (ttyvp == NULL) 105 return (EIO); 106 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 107 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 108 VOP_UNLOCK(ttyvp); 109 return (error); 110 } 111 112 /*ARGSUSED*/ 113 static int 114 cttyioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l) 115 { 116 struct vnode *ttyvp = cttyvp(l->l_proc); 117 int rv; 118 119 if (ttyvp == NULL) 120 return (EIO); 121 if (cmd == TIOCSCTTY) /* XXX */ 122 return (EINVAL); 123 if (cmd == TIOCNOTTY) { 124 mutex_enter(proc_lock); 125 if (!SESS_LEADER(l->l_proc)) { 126 l->l_proc->p_lflag &= ~PL_CONTROLT; 127 rv = 0; 128 } else 129 rv = EINVAL; 130 mutex_exit(proc_lock); 131 return (rv); 132 } 133 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED)); 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)); 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