1 /* $NetBSD: nullcons_subr.c,v 1.7 2009/02/28 00:40:47 tsutsui Exp $ */ 2 3 /*- 4 * Copyright (c) 2003 The NetBSD Foundation, Inc. 5 * 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: nullcons_subr.c,v 1.7 2009/02/28 00:40:47 tsutsui Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/proc.h> 34 #include <sys/user.h> 35 #include <sys/systm.h> 36 #include <sys/buf.h> 37 #include <sys/ioctl.h> 38 #include <sys/tty.h> 39 #include <sys/file.h> 40 #include <sys/conf.h> 41 #include <sys/vnode.h> 42 43 #include <dev/cons.h> 44 45 46 extern struct consdev *cn_tab; /* physical console device info */ 47 48 static struct tty *nulltty; /* null console tty */ 49 50 cons_decl(null); 51 52 dev_type_read(nullcndev_read); 53 dev_type_ioctl(nullcndev_ioctl); 54 dev_type_tty(nullcndev_tty); 55 56 static int nullcons_newdev(struct consdev *); 57 58 const struct cdevsw nullcn_devsw = { 59 nullopen, nullclose, nullcndev_read, nullwrite, nullcndev_ioctl, 60 nullstop, nullcndev_tty, nopoll, nommap, ttykqfilter, D_TTY 61 }; 62 63 /* 64 * null console device. We need it because of the ioctl() it handles, 65 * which in particular allows control terminal allocation through 66 * TIOCSCTTY ioctl. Without the latter, system won't even boot past init(8) 67 * invocation. 68 */ 69 int 70 nullcndev_read(dev, uio, flag) 71 dev_t dev; 72 struct uio *uio; 73 int flag; 74 { 75 76 return EIO; 77 } 78 79 int 80 nullcndev_ioctl(dev, cmd, data, flag, l) 81 dev_t dev; 82 u_long cmd; 83 void *data; 84 int flag; 85 struct lwp *l; 86 { 87 int error; 88 89 error = (*nulltty->t_linesw->l_ioctl)(nulltty, cmd, data, flag, l); 90 if (error != EPASSTHROUGH) 91 return (error); 92 93 error = ttioctl(nulltty, cmd, data, flag, l); 94 if (error != EPASSTHROUGH) 95 return (error); 96 97 return (0); 98 } 99 100 struct tty* 101 nullcndev_tty(dev) 102 dev_t dev; 103 { 104 105 return nulltty; 106 } 107 108 /* 109 * Mark console as no-op (null) console. Proper initialization is deferred 110 * to nullconsattach(). 111 */ 112 void 113 nullcnprobe(cn) 114 struct consdev *cn; 115 { 116 117 cn->cn_pri = CN_NULL; 118 cn->cn_dev = NODEV; 119 } 120 121 /* 122 * null console initialization. This includes allocation of a new device and 123 * a new tty. 124 */ 125 void 126 nullcninit(cn) 127 struct consdev *cn; 128 { 129 static struct consdev nullcn = cons_init(null); 130 131 nullcnprobe(&nullcn); 132 cn_tab = &nullcn; 133 } 134 135 /* 136 * Dumb getc() implementation. Simply blocks on call. 137 */ 138 int 139 nullcngetc(dev) 140 dev_t dev; 141 { 142 143 for(;;); 144 return (0); 145 } 146 147 /* 148 * Dumb putc() implementation. 149 */ 150 void 151 nullcnputc(dev, c) 152 dev_t dev; 153 int c; 154 { 155 156 } 157 158 /* 159 * Allocate a new console device and a tty to handle console ioctls. 160 */ 161 int 162 nullcons_newdev(cn) 163 struct consdev *cn; 164 { 165 int error; 166 int bmajor = -1, cmajor = -1; 167 168 if ((cn == NULL) || (cn->cn_pri != CN_NULL) || (cn->cn_dev != NODEV)) 169 return (0); 170 171 /* 172 * Attach no-op device to the device list. 173 */ 174 error = devsw_attach("nullcn", NULL, &bmajor, &nullcn_devsw, &cmajor); 175 if (error != 0) 176 return (error); 177 178 /* 179 * Allocate tty (mostly to have sane ioctl()). 180 */ 181 nulltty = ttymalloc(); 182 nulltty->t_dev = makedev(cmajor, 0); 183 tty_attach(nulltty); 184 cn->cn_dev = nulltty->t_dev; 185 186 return (0); 187 } 188 189 /* 190 * Pseudo-device attach function -- it's the right time to do the rest of 191 * initialization. 192 */ 193 void 194 nullconsattach(pdev_count) 195 int pdev_count; 196 { 197 198 nullcons_newdev(cn_tab); 199 } 200