1 /* $NetBSD: nullcons_subr.c,v 1.6 2008/04/28 20:23:47 martin 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 1.6 2008/04/28 20:23:47 martin 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 for(;;); 77 return (0); 78 } 79 80 int 81 nullcndev_ioctl(dev, cmd, data, flag, l) 82 dev_t dev; 83 u_long cmd; 84 void *data; 85 int flag; 86 struct lwp *l; 87 { 88 int error; 89 90 error = (*nulltty->t_linesw->l_ioctl)(nulltty, cmd, data, flag, l); 91 if (error != EPASSTHROUGH) 92 return (error); 93 94 error = ttioctl(nulltty, cmd, data, flag, l); 95 if (error != EPASSTHROUGH) 96 return (error); 97 98 return (0); 99 } 100 101 struct tty* 102 nullcndev_tty(dev) 103 dev_t dev; 104 { 105 106 return nulltty; 107 } 108 109 /* 110 * Mark console as no-op (null) console. Proper initialization is deferred 111 * to nullconsattach(). 112 */ 113 void 114 nullcnprobe(cn) 115 struct consdev *cn; 116 { 117 118 cn->cn_pri = CN_NULL; 119 cn->cn_dev = NODEV; 120 } 121 122 /* 123 * null console initialization. This includes allocation of a new device and 124 * a new tty. 125 */ 126 void 127 nullcninit(cn) 128 struct consdev *cn; 129 { 130 static struct consdev nullcn = cons_init(null); 131 132 nullcnprobe(&nullcn); 133 cn_tab = &nullcn; 134 } 135 136 /* 137 * Dumb getc() implementation. Simply blocks on call. 138 */ 139 int 140 nullcngetc(dev) 141 dev_t dev; 142 { 143 144 for(;;); 145 return (0); 146 } 147 148 /* 149 * Dumb putc() implementation. 150 */ 151 void 152 nullcnputc(dev, c) 153 dev_t dev; 154 int c; 155 { 156 157 } 158 159 /* 160 * Allocate a new console device and a tty to handle console ioctls. 161 */ 162 int 163 nullcons_newdev(cn) 164 struct consdev *cn; 165 { 166 int error; 167 int bmajor = -1, cmajor = -1; 168 169 if ((cn == NULL) || (cn->cn_pri != CN_NULL) || (cn->cn_dev != NODEV)) 170 return (0); 171 172 /* 173 * Attach no-op device to the device list. 174 */ 175 error = devsw_attach("nullcn", NULL, &bmajor, &nullcn_devsw, &cmajor); 176 if (error != 0) 177 return (error); 178 179 /* 180 * Allocate tty (mostly to have sane ioctl()). 181 */ 182 nulltty = ttymalloc(); 183 nulltty->t_dev = makedev(cmajor, 0); 184 tty_attach(nulltty); 185 cn->cn_dev = nulltty->t_dev; 186 187 return (0); 188 } 189 190 /* 191 * Pseudo-device attach function -- it's the right time to do the rest of 192 * initialization. 193 */ 194 void 195 nullconsattach(pdev_count) 196 int pdev_count; 197 { 198 199 nullcons_newdev(cn_tab); 200 } 201