1/* 2 * Copyright (c) 1997-2013 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/*- 29 * Copyright (c) 1982, 1986, 1991, 1993 30 * The Regents of the University of California. All rights reserved. 31 * 32 * Redistribution and use in source and binary forms, with or without 33 * modification, are permitted provided that the following conditions 34 * are met: 35 * 1. Redistributions of source code must retain the above copyright 36 * notice, this list of conditions and the following disclaimer. 37 * 2. Redistributions in binary form must reproduce the above copyright 38 * notice, this list of conditions and the following disclaimer in the 39 * documentation and/or other materials provided with the distribution. 40 * 3. All advertising materials mentioning features or use of this software 41 * must display the following acknowledgement: 42 * This product includes software developed by the University of 43 * California, Berkeley and its contributors. 44 * 4. Neither the name of the University nor the names of its contributors 45 * may be used to endorse or promote products derived from this software 46 * without specific prior written permission. 47 * 48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 51 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 58 * SUCH DAMAGE. 59 * 60 * @(#)tty_tty.c 8.2 (Berkeley) 9/23/93 61 */ 62 63/* 64 * Indirect driver for controlling tty. 65 */ 66#include <sys/param.h> 67#include <sys/systm.h> 68#include <sys/conf.h> 69#include <sys/ioctl.h> 70#include <sys/proc_internal.h> 71#include <sys/tty.h> 72#include <sys/vnode_internal.h> 73#include <sys/file_internal.h> 74#include <sys/kauth.h> 75 76/* Forward declarations for cdevsw[] entry */ 77/* XXX we should consider making these static */ 78int cttyopen(dev_t dev, int flag, int mode, proc_t p); 79int cttyread(dev_t dev, struct uio *uio, int flag); 80int cttywrite(dev_t dev, struct uio *uio, int flag); 81int cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p); 82int cttyselect(dev_t dev, int flag, void* wql, proc_t p); 83static vnode_t cttyvp(proc_t p); 84 85int 86cttyopen(dev_t dev, int flag, __unused int mode, proc_t p) 87{ 88 vnode_t ttyvp = cttyvp(p); 89 struct vfs_context context; 90 int error = 0; 91 int cttyflag, doclose = 0; 92 struct session *sessp; 93 94 if (ttyvp == NULL) 95 return (ENXIO); 96 97 context.vc_thread = current_thread(); 98 context.vc_ucred = kauth_cred_proc_ref(p); 99 100 sessp = proc_session(p); 101 session_lock(sessp); 102 cttyflag = sessp->s_flags & S_CTTYREF; 103 session_unlock(sessp); 104 105 /* 106 * A little hack--this device, used by many processes, 107 * happens to do an open on another device, which can 108 * cause unhappiness if the second-level open blocks indefinitely 109 * (as could be the case if the master side has hung up). Since 110 * we know that this driver doesn't care about the serializing 111 * opens and closes, we can drop the lock. To avoid opencount leak, 112 * open the vnode only for the first time. 113 */ 114 if (cttyflag == 0) { 115 devsw_unlock(dev, S_IFCHR); 116 error = VNOP_OPEN(ttyvp, flag, &context); 117 devsw_lock(dev, S_IFCHR); 118 119 if (error) 120 goto out; 121 122 /* 123 * If S_CTTYREF is set, some other thread did an open 124 * and was able to set the flag, now perform a close, else 125 * set the flag. 126 */ 127 session_lock(sessp); 128 if (cttyflag == (sessp->s_flags & S_CTTYREF)) 129 sessp->s_flags |= S_CTTYREF; 130 else 131 doclose = 1; 132 session_unlock(sessp); 133 134 /* 135 * We have to take a reference here to make sure a close 136 * gets called during revoke. Note that once a controlling 137 * tty gets opened by this driver, the only way close will 138 * get called is when the session leader , whose controlling 139 * tty is ttyvp, exits and vnode is revoked. We cannot 140 * redirect close from this driver because underlying controlling 141 * terminal might change and close may get redirected to a 142 * wrong vnode causing panic. 143 */ 144 if (doclose) { 145 devsw_unlock(dev, S_IFCHR); 146 VNOP_CLOSE(ttyvp, flag, &context); 147 devsw_lock(dev, S_IFCHR); 148 } else { 149 error = vnode_ref(ttyvp); 150 } 151 } 152out: 153 session_rele(sessp); 154 155 vnode_put(ttyvp); 156 kauth_cred_unref(&context.vc_ucred); 157 158 return (error); 159} 160 161int 162cttyread(__unused dev_t dev, struct uio *uio, int flag) 163{ 164 vnode_t ttyvp = cttyvp(current_proc()); 165 struct vfs_context context; 166 int error; 167 168 if (ttyvp == NULL) 169 return (EIO); 170 171 context.vc_thread = current_thread(); 172 context.vc_ucred = NOCRED; 173 174 error = VNOP_READ(ttyvp, uio, flag, &context); 175 vnode_put(ttyvp); 176 177 return (error); 178} 179 180int 181cttywrite(__unused dev_t dev, struct uio *uio, int flag) 182{ 183 vnode_t ttyvp = cttyvp(current_proc()); 184 struct vfs_context context; 185 int error; 186 187 if (ttyvp == NULL) 188 return (EIO); 189 190 context.vc_thread = current_thread(); 191 context.vc_ucred = NOCRED; 192 193 error = VNOP_WRITE(ttyvp, uio, flag, &context); 194 vnode_put(ttyvp); 195 196 return (error); 197} 198 199int 200cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p) 201{ 202 vnode_t ttyvp = cttyvp(current_proc()); 203 struct vfs_context context; 204 struct session *sessp; 205 int error = 0; 206 207 if (ttyvp == NULL) 208 return (EIO); 209 if (cmd == TIOCSCTTY) { /* don't allow controlling tty to be set */ 210 error = EINVAL; /* to controlling tty -- infinite recursion */ 211 goto out; 212 } 213 if (cmd == TIOCNOTTY) { 214 sessp = proc_session(p); 215 if (!SESS_LEADER(p, sessp)) { 216 OSBitAndAtomic(~((uint32_t)P_CONTROLT), &p->p_flag); 217 if (sessp != SESSION_NULL) 218 session_rele(sessp); 219 error = 0; 220 goto out; 221 } else { 222 if (sessp != SESSION_NULL) 223 session_rele(sessp); 224 error = EINVAL; 225 goto out; 226 } 227 } 228 context.vc_thread = current_thread(); 229 context.vc_ucred = NOCRED; 230 231 error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context); 232out: 233 vnode_put(ttyvp); 234 return (error); 235} 236 237int 238cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p) 239{ 240 vnode_t ttyvp = cttyvp(current_proc()); 241 struct vfs_context context; 242 int error; 243 244 context.vc_thread = current_thread(); 245 context.vc_ucred = NOCRED; 246 247 if (ttyvp == NULL) 248 return (1); /* try operation to get EOF/failure */ 249 error = VNOP_SELECT(ttyvp, flag, FREAD|FWRITE, wql, &context); 250 vnode_put(ttyvp); 251 return (error); 252} 253 254/* This returns vnode with ioref */ 255static vnode_t 256cttyvp(proc_t p) 257{ 258 vnode_t vp; 259 int vid; 260 struct session *sessp; 261 262 sessp = proc_session(p); 263 264 session_lock(sessp); 265 vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP); 266 vid = sessp->s_ttyvid; 267 session_unlock(sessp); 268 269 session_rele(sessp); 270 271 if (vp != NULLVP) { 272 /* cannot get an IO reference, return NULLVP */ 273 if (vnode_getwithvid(vp, vid) != 0) 274 vp = NULLVP; 275 } 276 return(vp); 277} 278 279