191 lines
4.3 KiB
C
191 lines
4.3 KiB
C
/* $NetBSD: nullcons_subr.c,v 1.13 2014/07/25 08:10:35 dholland Exp $ */
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/*-
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* Copyright (c) 2003 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: nullcons_subr.c,v 1.13 2014/07/25 08:10:35 dholland Exp $");
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/ioctl.h>
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#include <sys/tty.h>
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#include <sys/file.h>
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#include <sys/conf.h>
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#include <sys/vnode.h>
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#include <dev/cons.h>
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static struct tty *nulltty; /* null console tty */
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cons_decl(null);
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dev_type_read(nullcndev_read);
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dev_type_ioctl(nullcndev_ioctl);
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dev_type_tty(nullcndev_tty);
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static int nullcons_newdev(struct consdev *);
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const struct cdevsw nullcn_devsw = {
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.d_open = nullopen,
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.d_close = nullclose,
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.d_read = nullcndev_read,
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.d_write = nullwrite,
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.d_ioctl = nullcndev_ioctl,
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.d_stop = nullstop,
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.d_tty = nullcndev_tty,
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.d_poll = nopoll,
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.d_mmap = nommap,
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.d_kqfilter = ttykqfilter,
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.d_discard = nodiscard,
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.d_flag = D_TTY
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};
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/*
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* null console device. We need it because of the ioctl() it handles,
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* which in particular allows control terminal allocation through
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* TIOCSCTTY ioctl. Without the latter, system won't even boot past init(8)
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* invocation.
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*/
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int
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nullcndev_read(dev_t dev, struct uio *uio, int flag)
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{
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return EIO;
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}
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int
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nullcndev_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
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{
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int error;
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error = (*nulltty->t_linesw->l_ioctl)(nulltty, cmd, data, flag, l);
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if (error != EPASSTHROUGH)
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return error;
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error = ttioctl(nulltty, cmd, data, flag, l);
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if (error != EPASSTHROUGH)
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return error;
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return 0;
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}
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struct tty*
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nullcndev_tty(dev_t dev)
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{
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return nulltty;
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}
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/*
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* Mark console as no-op (null) console. Proper initialization is deferred
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* to nullconsattach().
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*/
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void
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nullcnprobe(struct consdev *cn)
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{
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cn->cn_pri = CN_NULL;
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cn->cn_dev = NODEV;
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}
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/*
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* null console initialization. This includes allocation of a new device and
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* a new tty.
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*/
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void
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nullcninit(struct consdev *cn)
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{
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static struct consdev nullcn = cons_init(null);
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nullcnprobe(&nullcn);
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cn_tab = &nullcn;
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}
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/*
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* Dumb getc() implementation. Simply blocks on call.
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*/
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int
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nullcngetc(dev_t dev)
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{
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for (;;)
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;
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return 0;
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}
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/*
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* Dumb putc() implementation.
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*/
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void
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nullcnputc(dev_t dev, int c)
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{
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}
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/*
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* Allocate a new console device and a tty to handle console ioctls.
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*/
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int
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nullcons_newdev(struct consdev *cn)
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{
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int error;
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int bmajor = -1, cmajor = -1;
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if ((cn == NULL) || (cn->cn_pri != CN_NULL) || (cn->cn_dev != NODEV))
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return 0;
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/*
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* Attach no-op device to the device list.
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*/
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error = devsw_attach("nullcn", NULL, &bmajor, &nullcn_devsw, &cmajor);
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if (error != 0)
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return error;
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/*
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* Allocate tty (mostly to have sane ioctl()).
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*/
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nulltty = tty_alloc();
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nulltty->t_dev = makedev(cmajor, 0);
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tty_attach(nulltty);
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cn->cn_dev = nulltty->t_dev;
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return 0;
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}
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/*
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* Pseudo-device attach function -- it's the right time to do the rest of
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* initialization.
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*/
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void
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nullconsattach(int pdev_count)
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{
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nullcons_newdev(cn_tab);
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}
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