sys/kern/tty_tty.c

   1 /*-
   2  * Copyright (c) 1982, 1986, 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)tty_tty.c   8.2 (Berkeley) 9/23/93
  34  * $FreeBSD: src/sys/kern/tty_tty.c,v 1.30 1999/09/25 18:24:24 phk Exp $
  35  * $DragonFly: src/sys/kern/tty_tty.c,v 1.12 2005/01/29 05:48:17 dillon Exp $
  36  */
  37
  38 /*
  39  * Indirect driver for controlling tty.
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/conf.h>
  45 #include <sys/lock.h>
  46 #include <sys/proc.h>
  47 #include <sys/ttycom.h>
  48 #include <sys/vnode.h>
  49 #include <sys/kernel.h>
  50
  51 static  d_open_t        cttyopen;
  52 static  d_close_t       cttyclose;
  53 static  d_read_t        cttyread;
  54 static  d_write_t       cttywrite;
  55 static  d_ioctl_t       cttyioctl;
  56 static  d_poll_t        cttypoll;
  57
  58 #define CDEV_MAJOR      1
  59 /* Don't make this static, since fdesc_vnops uses it. */
  60 struct cdevsw ctty_cdevsw = {
  61         /* name */      "ctty",
  62         /* maj */       CDEV_MAJOR,
  63         /* flags */     D_TTY,
  64         /* port */      NULL,
  65         /* clone */     NULL,
  66
  67         /* open */      cttyopen,
  68         /* close */     cttyclose,
  69         /* read */      cttyread,
  70         /* write */     cttywrite,
  71         /* ioctl */     cttyioctl,
  72         /* poll */      cttypoll,
  73         /* mmap */      nommap,
  74         /* strategy */  nostrategy,
  75         /* dump */      nodump,
  76         /* psize */     nopsize
  77 };
  78
  79 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
  80
  81 /*ARGSUSED*/
  82 static  int
  83 cttyopen(dev_t dev, int flag, int mode, struct thread *td)
  84 {
  85         struct proc *p = td->td_proc;
  86         struct vnode *ttyvp;
  87         int error;
  88
  89         KKASSERT(p);
  90         ttyvp = cttyvp(p);
  91         if (ttyvp) {
  92                 if (ttyvp->v_flag & VCTTYISOPEN) {
  93                         error = 0;
  94                 } else {
  95                         vsetflags(ttyvp, VCTTYISOPEN);
  96                         vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, td);
  97                         error = VOP_OPEN(ttyvp, flag, NOCRED, NULL, td);
  98                         if (error)
  99                                 vclrflags(ttyvp, VCTTYISOPEN);
 100                         VOP_UNLOCK(ttyvp, 0, td);
 101                 }
 102         } else {
 103                 error = ENXIO;
 104         }
 105         return (error);
 106 }
 107
 108 static int
 109 cttyclose(dev_t dev, int fflag, int devtype, struct thread *td)
 110 {
 111         struct proc *p = td->td_proc;
 112         struct vnode *ttyvp;
 113         int error;
 114
 115         KKASSERT(p);
 116         ttyvp = cttyvp(p);
 117         if (ttyvp == NULL) {
 118                 /*
 119                  * The tty may have been TIOCNOTTY'd, don't return an
 120                  * error on close.  We just have nothing to do.
 121                  */
 122                 /* error = EIO; */
 123                 error = 0;
 124         } else if (ttyvp->v_flag & VCTTYISOPEN) {
 125                 vclrflags(ttyvp, VCTTYISOPEN);
 126                 error = vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, td);
 127                 if (error == 0) {
 128                         error = VOP_CLOSE(ttyvp, fflag, td);
 129                         VOP_UNLOCK(ttyvp, 0, td);
 130                 }
 131         } else {
 132                 error = 0;
 133         }
 134         return(error);
 135 }
 136
 137 /*ARGSUSED*/
 138 static  int
 139 cttyread(dev, uio, flag)
 140         dev_t dev;
 141         struct uio *uio;
 142         int flag;
 143 {
 144         struct thread *td = uio->uio_td;
 145         struct proc *p = td->td_proc;
 146         struct vnode *ttyvp;
 147         int error;
 148
 149         KKASSERT(p);
 150         ttyvp = cttyvp(p);
 151         if (ttyvp == NULL)
 152                 return (EIO);
 153         vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, td);
 154         error = VOP_READ(ttyvp, uio, flag, NOCRED);
 155         VOP_UNLOCK(ttyvp, 0, td);
 156         return (error);
 157 }
 158
 159 /*ARGSUSED*/
 160 static  int
 161 cttywrite(dev, uio, flag)
 162         dev_t dev;
 163         struct uio *uio;
 164         int flag;
 165 {
 166         struct thread *td = uio->uio_td;
 167         struct proc *p = td->td_proc;
 168         struct vnode *ttyvp;
 169         int error;
 170
 171         KKASSERT(p);
 172         ttyvp = cttyvp(p);
 173         if (ttyvp == NULL)
 174                 return (EIO);
 175         vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, td);
 176         error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
 177         VOP_UNLOCK(ttyvp, 0, td);
 178         return (error);
 179 }
 180
 181 /*ARGSUSED*/
 182 static  int
 183 cttyioctl(dev, cmd, addr, flag, td)
 184         dev_t dev;
 185         u_long cmd;
 186         caddr_t addr;
 187         int flag;
 188         struct thread *td;
 189 {
 190         struct vnode *ttyvp;
 191         struct proc *p = td->td_proc;
 192
 193         KKASSERT(p);
 194         ttyvp = cttyvp(p);
 195         if (ttyvp == NULL)
 196                 return (EIO);
 197         if (cmd == TIOCSCTTY)  /* don't allow controlling tty to be set    */
 198                 return EINVAL; /* to controlling tty -- infinite recursion */
 199         if (cmd == TIOCNOTTY) {
 200                 if (!SESS_LEADER(p)) {
 201                         p->p_flag &= ~P_CONTROLT;
 202                         return (0);
 203                 } else
 204                         return (EINVAL);
 205         }
 206         return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, td));
 207 }
 208
 209 /*ARGSUSED*/
 210 static  int
 211 cttypoll(dev_t dev, int events, struct thread *td)
 212 {
 213         struct vnode *ttyvp;
 214         struct proc *p = td->td_proc;
 215
 216         KKASSERT(p);
 217         ttyvp = cttyvp(p);
 218         if (ttyvp == NULL)
 219                 /* try operation to get EOF/failure */
 220                 return (seltrue(dev, events, td));
 221         return (VOP_POLL(ttyvp, events, p->p_ucred, td));
 222 }
 223
 224 static void ctty_drvinit (void *unused);
 225 static void
 226 ctty_drvinit(unused)
 227         void *unused;
 228 {
 229         cdevsw_add(&ctty_cdevsw, 0, 0);
 230         make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "tty");
 231 }
 232
 233 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)