bsd/kern/tty_tty.c

   1 /*
   2  * Copyright (c) 1997-2006 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 cttyread(dev_t dev, struct uio *uio, int flag);
  80 int cttywrite(dev_t dev, struct uio *uio, int flag);
  81 int cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p);
  82 int cttyselect(dev_t dev, int flag, void* wql, proc_t p);
  83 static vnode_t cttyvp(proc_t p);
  84
  85
  86 int
  87 cttyopen(__unused dev_t dev, int flag, __unused int mode, proc_t p)
  88 {
  89         vnode_t ttyvp = cttyvp(p);
  90         struct vfs_context context;
  91         int error;
  92
  93         if (ttyvp == NULL)
  94                 return (ENXIO);
  95
  96         context.vc_thread = current_thread();
  97         context.vc_ucred = kauth_cred_proc_ref(p);
  98
  99         error = VNOP_OPEN(ttyvp, flag, &context);
 100         vnode_put(ttyvp);
 101         kauth_cred_unref(&context.vc_ucred);
 102
 103         return (error);
 104 }
 105
 106 int
 107 cttyread(__unused dev_t dev, struct uio *uio, int flag)
 108 {
 109         vnode_t ttyvp = cttyvp(current_proc());
 110         struct vfs_context context;
 111         int error;
 112
 113         if (ttyvp == NULL)
 114                 return (EIO);
 115
 116         context.vc_thread = current_thread();
 117         context.vc_ucred = NOCRED;
 118
 119         error = VNOP_READ(ttyvp, uio, flag, &context);
 120         vnode_put(ttyvp);
 121
 122         return (error);
 123 }
 124
 125 int
 126 cttywrite(__unused dev_t dev, struct uio *uio, int flag)
 127 {
 128         vnode_t ttyvp = cttyvp(current_proc());
 129         struct vfs_context context;
 130         int error;
 131
 132         if (ttyvp == NULL)
 133                 return (EIO);
 134
 135         context.vc_thread = current_thread();
 136         context.vc_ucred = NOCRED;
 137
 138         error = VNOP_WRITE(ttyvp, uio, flag, &context);
 139         vnode_put(ttyvp);
 140
 141         return (error);
 142 }
 143
 144 int
 145 cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p)
 146 {
 147         vnode_t ttyvp = cttyvp(current_proc());
 148         struct vfs_context context;
 149         struct session *sessp;
 150         int error = 0;
 151
 152         if (ttyvp == NULL)
 153                 return (EIO);
 154         if (cmd == TIOCSCTTY)  { /* don't allow controlling tty to be set    */
 155                 error = EINVAL; /* to controlling tty -- infinite recursion */
 156                 goto out;
 157         }
 158         if (cmd == TIOCNOTTY) {
 159                 sessp = proc_session(p);
 160                 if (!SESS_LEADER(p, sessp)) {
 161                         OSBitAndAtomic(~((uint32_t)P_CONTROLT), &p->p_flag);
 162                         if (sessp != SESSION_NULL)
 163                                 session_rele(sessp);
 164                         error = 0;
 165                         goto out;
 166                 } else {
 167                         if (sessp != SESSION_NULL)
 168                                 session_rele(sessp);
 169                         error = EINVAL;
 170                         goto out;
 171                 }
 172         }
 173         context.vc_thread = current_thread();
 174         context.vc_ucred = NOCRED;
 175
 176         error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context);
 177 out:
 178         vnode_put(ttyvp);
 179         return (error);
 180 }
 181
 182 int
 183 cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p)
 184 {
 185         vnode_t ttyvp = cttyvp(current_proc());
 186         struct vfs_context context;
 187         int error;
 188
 189         context.vc_thread = current_thread();
 190         context.vc_ucred = NOCRED;
 191
 192         if (ttyvp == NULL)
 193                 return (1);     /* try operation to get EOF/failure */
 194         error = VNOP_SELECT(ttyvp, flag, FREAD|FWRITE, wql, &context);
 195         vnode_put(ttyvp);
 196         return (error);
 197 }
 198
 199 /* This returns vnode with ioref */
 200 static vnode_t
 201 cttyvp(proc_t p)
 202 {
 203         vnode_t vp;
 204         int vid;
 205         struct session *sessp;
 206
 207         sessp = proc_session(p);
 208
 209         session_lock(sessp);
 210         vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP);
 211         vid = sessp->s_ttyvid;
 212         session_unlock(sessp);
 213
 214         session_rele(sessp);
 215
 216         if (vp != NULLVP) {
 217                 /* cannot get an IO reference, return NULLVP */
 218                 if (vnode_getwithvid(vp, vid) != 0)
 219                         vp = NULLVP;
 220         }
 221         return(vp);
 222 }
 223