FreeBSD/Linux Kernel Cross Reference
sys/dev/nullcons_subr.c

     /*      $NetBSD: nullcons_subr.c,v 1.6.10.1 2009/03/24 20:32:08 snj Exp $       */
     
     /*-
      * Copyright (c) 2003 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: nullcons_subr.c,v 1.6.10.1 2009/03/24 20:32:08 snj Exp $");
    
    #include <sys/param.h>
    #include <sys/proc.h>
    #include <sys/user.h>
    #include <sys/systm.h>
    #include <sys/buf.h>
    #include <sys/ioctl.h>
    #include <sys/tty.h>
    #include <sys/file.h>
    #include <sys/conf.h>
    #include <sys/vnode.h>
    
    #include <dev/cons.h>
    
    
    extern struct consdev *cn_tab;          /* physical console device info */
    
    static struct tty *nulltty;             /* null console tty */
    
    cons_decl(null);
    
    dev_type_read(nullcndev_read);
    dev_type_ioctl(nullcndev_ioctl);
    dev_type_tty(nullcndev_tty);
    
    static int      nullcons_newdev(struct consdev *);
    
    const struct cdevsw nullcn_devsw = {
            nullopen, nullclose, nullcndev_read, nullwrite, nullcndev_ioctl,
            nullstop, nullcndev_tty, nopoll, nommap, ttykqfilter, D_TTY
    };
    
    /*
     * null console device. We need it because of the ioctl() it handles,
     * which in particular allows control terminal allocation through
     * TIOCSCTTY ioctl. Without the latter, system won't even boot past init(8)
     * invocation.
     */
    int
    nullcndev_read(dev, uio, flag)
            dev_t dev;
            struct uio *uio;
            int flag;
    {
    
            return EIO;
    }
    
    int
    nullcndev_ioctl(dev, cmd, data, flag, l)
            dev_t dev;
            u_long cmd;
            void *data;
            int flag;
            struct lwp *l;
    {
            int error;
    
            error = (*nulltty->t_linesw->l_ioctl)(nulltty, cmd, data, flag, l);
            if (error != EPASSTHROUGH)
                    return (error);
    
            error = ttioctl(nulltty, cmd, data, flag, l);
            if (error != EPASSTHROUGH)
                    return (error);
    
            return (0);
    }
    
   struct tty*
   nullcndev_tty(dev)
           dev_t dev;
   {
   
           return nulltty;
   }
   
   /*
    * Mark console as no-op (null) console. Proper initialization is deferred
    * to nullconsattach().
    */
   void
   nullcnprobe(cn)
           struct consdev *cn;
   {
   
           cn->cn_pri = CN_NULL;
           cn->cn_dev = NODEV;
   }
   
   /*
    * null console initialization. This includes allocation of a new device and
    * a new tty.
    */
   void
   nullcninit(cn)
           struct consdev *cn;
   {
           static struct consdev nullcn = cons_init(null);
   
           nullcnprobe(&nullcn);
           cn_tab = &nullcn;
   }
   
   /*
    * Dumb getc() implementation. Simply blocks on call.
    */
   int
   nullcngetc(dev)
           dev_t dev;
   {
   
           for(;;);
           return (0);
   }
   
   /*
    * Dumb putc() implementation.
    */
   void
   nullcnputc(dev, c)
           dev_t dev;
           int c;
   {
   
   }
   
   /*
    * Allocate a new console device and a tty to handle console ioctls.
    */
   int
   nullcons_newdev(cn)
           struct consdev *cn;
   {
           int error;
           int bmajor = -1, cmajor = -1;
   
           if ((cn == NULL) || (cn->cn_pri != CN_NULL) || (cn->cn_dev != NODEV))
                   return (0);
   
           /*
            * Attach no-op device to the device list.
            */
           error = devsw_attach("nullcn", NULL, &bmajor, &nullcn_devsw, &cmajor);
           if (error != 0)
                   return (error);
   
           /*
            * Allocate tty (mostly to have sane ioctl()).
            */
           nulltty = ttymalloc();
           nulltty->t_dev = makedev(cmajor, 0);
           tty_attach(nulltty);
           cn->cn_dev = nulltty->t_dev;
   
           return (0);
   }
   
   /*
    * Pseudo-device attach function -- it's the right time to do the rest of
    * initialization.
    */
   void
   nullconsattach(pdev_count)
           int pdev_count;
   {
   
           nullcons_newdev(cn_tab);
   }

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