bsd/kern/tty_tty.c

   1 /*
   2  * Copyright (c) 1997-2012 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 */
  78 int cttyopen(dev_t dev, int flag, int mode, proc_t p);
  79 int cttyclose(dev_t dev, int flag, int mode, proc_t p);
  80 int cttyread(dev_t dev, struct uio *uio, int flag);
  81 int cttywrite(dev_t dev, struct uio *uio, int flag);
  82 int cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p);
  83 int cttyselect(dev_t dev, int flag, void* wql, proc_t p);
  84 static vnode_t cttyvp(proc_t p);
  85
  86 int
  87 cttyopen(dev_t dev, int flag, __unused int mode, proc_t p)
  88 {
  89         vnode_t ttyvp;
  90         int error;
  91
  92         /*
  93          * A little hack--this device, used by many processes,
  94          * does an open on another device, which can cause unhappiness
  95          * if the second-level open blocks indefinitely (e.g. if the
  96          * master side has hung up).  This driver doesn't care
  97          * about serializing opens and closes, so drop the lock.
  98          */
  99         devsw_unlock(dev, S_IFCHR);
 100
 101         if ((ttyvp = cttyvp(p)) == NULL) {
 102                 error = ENXIO;
 103         } else {
 104                 struct vfs_context context;
 105
 106                 context.vc_thread = current_thread();
 107                 context.vc_ucred = kauth_cred_proc_ref(p);
 108
 109                 error = VNOP_OPEN(ttyvp, flag, &context);
 110
 111                 kauth_cred_unref(&context.vc_ucred);
 112                 vnode_put(ttyvp);
 113         }
 114
 115         devsw_lock(dev, S_IFCHR);
 116         return (error);
 117 }
 118
 119 /*
 120  * This driver is marked D_TRACKCLOSE and so gets a close
 121  * for every open so that ttyvp->v_specinfo->si_count can be kept sane.
 122  */
 123 int
 124 cttyclose(dev_t dev, int flag, __unused int mode, proc_t p)
 125 {
 126         vnode_t ttyvp;
 127         int error;
 128
 129         /* See locking commentary above. */
 130
 131         devsw_unlock(dev, S_IFCHR);
 132
 133         if ((ttyvp = cttyvp(p)) == NULL) {
 134                 error = ENXIO;
 135         } else {
 136                 struct vfs_context context;
 137
 138                 context.vc_thread = current_thread();
 139                 context.vc_ucred = kauth_cred_proc_ref(p);
 140
 141                 error = VNOP_CLOSE(ttyvp, flag, &context);
 142
 143                 kauth_cred_unref(&context.vc_ucred);
 144                 vnode_put(ttyvp);
 145         }
 146
 147         devsw_lock(dev, S_IFCHR);
 148         return (error);
 149 }
 150
 151 int
 152 cttyread(__unused dev_t dev, struct uio *uio, int flag)
 153 {
 154         vnode_t ttyvp = cttyvp(current_proc());
 155         struct vfs_context context;
 156         int error;
 157
 158         if (ttyvp == NULL)
 159                 return (EIO);
 160
 161         context.vc_thread = current_thread();
 162         context.vc_ucred = NOCRED;
 163
 164         error = VNOP_READ(ttyvp, uio, flag, &context);
 165         vnode_put(ttyvp);
 166
 167         return (error);
 168 }
 169
 170 int
 171 cttywrite(__unused dev_t dev, struct uio *uio, int flag)
 172 {
 173         vnode_t ttyvp = cttyvp(current_proc());
 174         struct vfs_context context;
 175         int error;
 176
 177         if (ttyvp == NULL)
 178                 return (EIO);
 179
 180         context.vc_thread = current_thread();
 181         context.vc_ucred = NOCRED;
 182
 183         error = VNOP_WRITE(ttyvp, uio, flag, &context);
 184         vnode_put(ttyvp);
 185
 186         return (error);
 187 }
 188
 189 int
 190 cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p)
 191 {
 192         vnode_t ttyvp = cttyvp(current_proc());
 193         struct vfs_context context;
 194         struct session *sessp;
 195         int error = 0;
 196
 197         if (ttyvp == NULL)
 198                 return (EIO);
 199         if (cmd == TIOCSCTTY)  { /* don't allow controlling tty to be set    */
 200                 error = EINVAL; /* to controlling tty -- infinite recursion */
 201                 goto out;
 202         }
 203         if (cmd == TIOCNOTTY) {
 204                 sessp = proc_session(p);
 205                 if (!SESS_LEADER(p, sessp)) {
 206                         OSBitAndAtomic(~((uint32_t)P_CONTROLT), &p->p_flag);
 207                         if (sessp != SESSION_NULL)
 208                                 session_rele(sessp);
 209                         error = 0;
 210                         goto out;
 211                 } else {
 212                         if (sessp != SESSION_NULL)
 213                                 session_rele(sessp);
 214                         error = EINVAL;
 215                         goto out;
 216                 }
 217         }
 218         context.vc_thread = current_thread();
 219         context.vc_ucred = NOCRED;
 220
 221         error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context);
 222 out:
 223         vnode_put(ttyvp);
 224         return (error);
 225 }
 226
 227 int
 228 cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p)
 229 {
 230         vnode_t ttyvp = cttyvp(current_proc());
 231         struct vfs_context context;
 232         int error;
 233
 234         context.vc_thread = current_thread();
 235         context.vc_ucred = NOCRED;
 236
 237         if (ttyvp == NULL)
 238                 return (1);     /* try operation to get EOF/failure */
 239         error = VNOP_SELECT(ttyvp, flag, FREAD|FWRITE, wql, &context);
 240         vnode_put(ttyvp);
 241         return (error);
 242 }
 243
 244 /* This returns vnode with ioref */
 245 static vnode_t
 246 cttyvp(proc_t p)
 247 {
 248         vnode_t vp;
 249         int vid;
 250         struct session *sessp;
 251
 252         sessp = proc_session(p);
 253
 254         session_lock(sessp);
 255         vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP);
 256         vid = sessp->s_ttyvid;
 257         session_unlock(sessp);
 258
 259         session_rele(sessp);
 260
 261         if (vp != NULLVP) {
 262                 /* cannot get an IO reference, return NULLVP */
 263                 if (vnode_getwithvid(vp, vid) != 0)
 264                         vp = NULLVP;
 265         }
 266         return(vp);
 267 }
 268