The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/tty_tty.c

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    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  * $FreeBSD$
   35  */
   36 
   37 /*
   38  * Indirect driver for controlling tty.
   39  */
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/conf.h>
   44 #include <sys/lock.h>
   45 #include <sys/proc.h>
   46 #include <sys/ttycom.h>
   47 #include <sys/vnode.h>
   48 #include <sys/kernel.h>
   49 
   50 static  d_open_t        cttyopen;
   51 static  d_read_t        cttyread;
   52 static  d_write_t       cttywrite;
   53 static  d_ioctl_t       cttyioctl;
   54 static  d_poll_t        cttypoll;
   55 
   56 #define CDEV_MAJOR      1
   57 /* Don't make this static, since fdesc_vnops uses it. */
   58 struct cdevsw ctty_cdevsw = {
   59         /* open */      cttyopen,
   60         /* close */     nullclose,
   61         /* read */      cttyread,
   62         /* write */     cttywrite,
   63         /* ioctl */     cttyioctl,
   64         /* poll */      cttypoll,
   65         /* mmap */      nommap,
   66         /* strategy */  nostrategy,
   67         /* name */      "ctty",
   68         /* maj */       CDEV_MAJOR,
   69         /* dump */      nodump,
   70         /* psize */     nopsize,
   71         /* flags */     D_TTY,
   72         /* bmaj */      -1
   73 };
   74 
   75 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
   76 
   77 /*ARGSUSED*/
   78 static  int
   79 cttyopen(dev, flag, mode, p)
   80         dev_t dev;
   81         int flag, mode;
   82         struct proc *p;
   83 {
   84         struct vnode *ttyvp = cttyvp(p);
   85         int error;
   86 
   87         if (ttyvp == NULL)
   88                 return (ENXIO);
   89         vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
   90 #ifdef PARANOID
   91         /*
   92          * Since group is tty and mode is 620 on most terminal lines
   93          * and since sessions protect terminals from processes outside
   94          * your session, this check is probably no longer necessary.
   95          * Since it inhibits setuid root programs that later switch
   96          * to another user from accessing /dev/tty, we have decided
   97          * to delete this test. (mckusick 5/93)
   98          */
   99         error = VOP_ACCESS(ttyvp,
  100           (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
  101         if (!error)
  102 #endif /* PARANOID */
  103                 error = VOP_OPEN(ttyvp, flag, NOCRED, p);
  104         VOP_UNLOCK(ttyvp, 0, p);
  105         return (error);
  106 }
  107 
  108 /*ARGSUSED*/
  109 static  int
  110 cttyread(dev, uio, flag)
  111         dev_t dev;
  112         struct uio *uio;
  113         int flag;
  114 {
  115         struct proc *p = uio->uio_procp;
  116         register struct vnode *ttyvp = cttyvp(p);
  117         int error;
  118 
  119         if (ttyvp == NULL)
  120                 return (EIO);
  121         vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
  122         error = VOP_READ(ttyvp, uio, flag, NOCRED);
  123         VOP_UNLOCK(ttyvp, 0, p);
  124         return (error);
  125 }
  126 
  127 /*ARGSUSED*/
  128 static  int
  129 cttywrite(dev, uio, flag)
  130         dev_t dev;
  131         struct uio *uio;
  132         int flag;
  133 {
  134         struct proc *p = uio->uio_procp;
  135         struct vnode *ttyvp = cttyvp(uio->uio_procp);
  136         int error;
  137 
  138         if (ttyvp == NULL)
  139                 return (EIO);
  140         vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
  141         error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
  142         VOP_UNLOCK(ttyvp, 0, p);
  143         return (error);
  144 }
  145 
  146 /*ARGSUSED*/
  147 static  int
  148 cttyioctl(dev, cmd, addr, flag, p)
  149         dev_t dev;
  150         u_long cmd;
  151         caddr_t addr;
  152         int flag;
  153         struct proc *p;
  154 {
  155         struct vnode *ttyvp = cttyvp(p);
  156 
  157         if (ttyvp == NULL)
  158                 return (EIO);
  159         if (cmd == TIOCSCTTY)  /* don't allow controlling tty to be set    */
  160                 return EINVAL; /* to controlling tty -- infinite recursion */
  161         if (cmd == TIOCNOTTY) {
  162                 if (!SESS_LEADER(p)) {
  163                         p->p_flag &= ~P_CONTROLT;
  164                         return (0);
  165                 } else
  166                         return (EINVAL);
  167         }
  168         return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
  169 }
  170 
  171 /*ARGSUSED*/
  172 static  int
  173 cttypoll(dev, events, p)
  174         dev_t dev;
  175         int events;
  176         struct proc *p;
  177 {
  178         struct vnode *ttyvp = cttyvp(p);
  179 
  180         if (ttyvp == NULL)
  181                 /* try operation to get EOF/failure */
  182                 return (seltrue(dev, events, p));
  183         return (VOP_POLL(ttyvp, events, p->p_ucred, p));
  184 }
  185 
  186 static void ctty_drvinit __P((void *unused));
  187 static void
  188 ctty_drvinit(unused)
  189         void *unused;
  190 {
  191 
  192         make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "tty");
  193 }
  194 
  195 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)

Cache object: d92514179f10b25bfca00b10ae53aaf2


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