1 /* $NetBSD: nullcons_subr.c,v 1.1 2003/10/17 20:27:38 cdi 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 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the NetBSD 18 * Foundation, Inc. and its contributors. 19 * 4. Neither the name of The NetBSD Foundation nor the names of its 20 * contributors may be used to endorse or promote products derived 21 * from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 27 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: nullcons_subr.c,v 1.1 2003/10/17 20:27:38 cdi Exp $"); 38 39 #include <sys/param.h> 40 #include <sys/proc.h> 41 #include <sys/user.h> 42 #include <sys/systm.h> 43 #include <sys/buf.h> 44 #include <sys/ioctl.h> 45 #include <sys/tty.h> 46 #include <sys/file.h> 47 #include <sys/conf.h> 48 #include <sys/vnode.h> 49 50 #include <dev/cons.h> 51 52 53 extern struct consdev *cn_tab; /* physical console device info */ 54 55 static struct tty *nulltty; /* null console tty */ 56 57 cons_decl(null); 58 59 dev_type_read(nullcndev_read); 60 dev_type_ioctl(nullcndev_ioctl); 61 dev_type_tty(nullcndev_tty); 62 63 static int nullcons_newdev __P((struct consdev *)); 64 65 const struct cdevsw nullcn_devsw = { 66 nullopen, nullclose, nullcndev_read, nullwrite, nullcndev_ioctl, 67 nullstop, nullcndev_tty, nopoll, nommap, ttykqfilter, D_TTY 68 }; 69 70 /* 71 * null console device. We need it because of the ioctl() it handles, 72 * which in particular allows control terminal allocation through 73 * TIOCSCTTY ioctl. Without the latter, system won't even boot past init(8) 74 * invocation. 75 */ 76 int 77 nullcndev_read(dev, uio, flag) 78 dev_t dev; 79 struct uio *uio; 80 int flag; 81 { 82 83 for(;;); 84 return (0); 85 } 86 87 int 88 nullcndev_ioctl(dev, cmd, data, flag, p) 89 dev_t dev; 90 u_long cmd; 91 caddr_t data; 92 int flag; 93 struct proc *p; 94 { 95 int error; 96 97 error = (*nulltty->t_linesw->l_ioctl)(nulltty, cmd, data, flag, p); 98 if (error != EPASSTHROUGH) 99 return (error); 100 101 error = ttioctl(nulltty, cmd, data, flag, p); 102 if (error != EPASSTHROUGH) 103 return (error); 104 105 return (0); 106 } 107 108 struct tty* 109 nullcndev_tty(dev) 110 dev_t dev; 111 { 112 113 return nulltty; 114 } 115 116 /* 117 * Mark console as no-op (null) console. Proper initialization is deferred 118 * to nullconsattach(). 119 */ 120 void 121 nullcnprobe(cn) 122 struct consdev *cn; 123 { 124 125 cn->cn_pri = CN_NULL; 126 cn->cn_dev = NODEV; 127 } 128 129 /* 130 * null console initialization. This includes allocation of a new device and 131 * a new tty. 132 */ 133 void 134 nullcninit(cn) 135 struct consdev *cn; 136 { 137 static struct consdev nullcn = cons_init(null); 138 139 nullcnprobe(&nullcn); 140 cn_tab = &nullcn; 141 } 142 143 /* 144 * Dumb getc() implementation. Simply blocks on call. 145 */ 146 int 147 nullcngetc(dev) 148 dev_t dev; 149 { 150 151 for(;;); 152 return (0); 153 } 154 155 /* 156 * Dumb putc() implementation. 157 */ 158 void 159 nullcnputc(dev, c) 160 dev_t dev; 161 int c; 162 { 163 164 } 165 166 /* 167 * Allocate a new console device and a tty to handle console ioctls. 168 */ 169 int 170 nullcons_newdev(cn) 171 struct consdev *cn; 172 { 173 int error; 174 int bmajor = -1, cmajor = -1; 175 176 if ((cn == NULL) || (cn->cn_pri != CN_NULL) || (cn->cn_dev != NODEV)) 177 return (0); 178 179 /* 180 * Attach no-op device to the device list. 181 */ 182 error = devsw_attach("nullcn", NULL, &bmajor, &nullcn_devsw, &cmajor); 183 if (error != 0) 184 return (error); 185 186 /* 187 * Allocate tty (mostly to have sane ioctl()). 188 */ 189 nulltty = ttymalloc(); 190 nulltty->t_dev = makedev(cmajor, 0); 191 tty_attach(nulltty); 192 cn->cn_dev = nulltty->t_dev; 193 194 return (0); 195 } 196 197 /* 198 * Pseudo-device attach function -- it's the right time to do the rest of 199 * initialization. 200 */ 201 void 202 nullconsattach(pdev_count) 203 int pdev_count; 204 { 205 206 nullcons_newdev(cn_tab); 207 } 208