tty_tty.c revision 1.40.18.1
1 /* $NetBSD: tty_tty.c,v 1.40.18.1 2017/04/27 05:36:37 pgoyette 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 1.40.18.1 2017/04/27 05:36:37 pgoyette 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 #include <sys/localcount.h> 51 52 /* XXXSMP */ 53 #define cttyvp(p) ((p)->p_lflag & PL_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 54 55 /*ARGSUSED*/ 56 static int 57 cttyopen(dev_t dev, int flag, int mode, struct lwp *l) 58 { 59 struct vnode *ttyvp = cttyvp(l->l_proc); 60 int error; 61 62 if (ttyvp == NULL) 63 return (ENXIO); 64 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 65 #ifdef PARANOID 66 /* 67 * Since group is tty and mode is 620 on most terminal lines 68 * and since sessions protect terminals from processes outside 69 * your session, this check is probably no longer necessary. 70 * Since it inhibits setuid root programs that later switch 71 * to another user from accessing /dev/tty, we have decided 72 * to delete this test. (mckusick 5/93) 73 */ 74 error = VOP_ACCESS(ttyvp, 75 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), l->l_cred, l); 76 if (!error) 77 #endif /* PARANOID */ 78 error = VOP_OPEN(ttyvp, flag, NOCRED); 79 VOP_UNLOCK(ttyvp); 80 return (error); 81 } 82 83 /*ARGSUSED*/ 84 static int 85 cttyread(dev_t dev, struct uio *uio, int flag) 86 { 87 struct vnode *ttyvp = cttyvp(curproc); 88 int error; 89 90 if (ttyvp == NULL) 91 return (EIO); 92 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 93 error = VOP_READ(ttyvp, uio, flag, NOCRED); 94 VOP_UNLOCK(ttyvp); 95 return (error); 96 } 97 98 /*ARGSUSED*/ 99 static int 100 cttywrite(dev_t dev, struct uio *uio, int flag) 101 { 102 struct vnode *ttyvp = cttyvp(curproc); 103 int error; 104 105 if (ttyvp == NULL) 106 return (EIO); 107 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 108 error = VOP_WRITE(ttyvp, uio, flag, NOCRED); 109 VOP_UNLOCK(ttyvp); 110 return (error); 111 } 112 113 /*ARGSUSED*/ 114 static int 115 cttyioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l) 116 { 117 struct vnode *ttyvp = cttyvp(l->l_proc); 118 int rv; 119 120 if (ttyvp == NULL) 121 return (EIO); 122 if (cmd == TIOCSCTTY) /* XXX */ 123 return (EINVAL); 124 if (cmd == TIOCNOTTY) { 125 mutex_enter(proc_lock); 126 if (!SESS_LEADER(l->l_proc)) { 127 l->l_proc->p_lflag &= ~PL_CONTROLT; 128 rv = 0; 129 } else 130 rv = EINVAL; 131 mutex_exit(proc_lock); 132 return (rv); 133 } 134 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED)); 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)); 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 DEVSW_MODULE_INIT 162 .d_open = cttyopen, 163 .d_close = nullclose, 164 .d_read = cttyread, 165 .d_write = cttywrite, 166 .d_ioctl = cttyioctl, 167 .d_stop = nullstop, 168 .d_tty = notty, 169 .d_poll = cttypoll, 170 .d_mmap = nommap, 171 .d_kqfilter = cttykqfilter, 172 .d_discard = nodiscard, 173 .d_flag = D_TTY 174 }; 175
Indexes created Mon Sep 29 21:09:56 GMT 2025