sys/kern/tty_tty.c

   1 /*      $NetBSD: tty_tty.c,v 1.36 2007/11/26 19:02:05 pooka 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 1.36 2007/11/26 19:02:05 pooka 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, 0);
  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, 0);
  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, 0);
 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 };