cons.c revision 1.33
1 /* $NetBSD: cons.c,v 1.33 1999/08/04 14:40:54 leo Exp $ */ 2 3 /* 4 * Copyright (c) 1988 University of Utah. 5 * Copyright (c) 1990, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * from: Utah $Hdr: cons.c 1.7 92/01/21$ 41 * 42 * @(#)cons.c 8.2 (Berkeley) 1/12/94 43 */ 44 45 #include <sys/param.h> 46 #include <sys/proc.h> 47 #include <sys/user.h> 48 #include <sys/systm.h> 49 #include <sys/buf.h> 50 #include <sys/ioctl.h> 51 #include <sys/tty.h> 52 #include <sys/file.h> 53 #include <sys/conf.h> 54 #include <sys/vnode.h> 55 56 #include <dev/cons.h> 57 58 struct tty *constty = NULL; /* virtual console output device */ 59 struct consdev *cn_tab; /* physical console device info */ 60 struct vnode *cn_devvp; /* vnode for underlying device. */ 61 62 int 63 cnopen(dev, flag, mode, p) 64 dev_t dev; 65 int flag, mode; 66 struct proc *p; 67 { 68 69 if (cn_tab == NULL) 70 return (0); 71 72 /* 73 * always open the 'real' console device, so we don't get nailed 74 * later. This follows normal device semantics; they always get 75 * open() calls. 76 */ 77 dev = cn_tab->cn_dev; 78 if (dev == NODEV) { 79 /* 80 * This is most likely an error in the console attach 81 * code. Panicing looks better than jumping into nowhere 82 * through cdevsw below.... 83 */ 84 panic("cnopen: cn_tab->cn_dev == NODEV\n"); 85 } 86 87 if (cn_devvp == NULLVP) { 88 /* try to get a reference on its vnode, but fail silently */ 89 cdevvp(dev, &cn_devvp); 90 } 91 return ((*cdevsw[major(dev)].d_open)(dev, flag, mode, p)); 92 } 93 94 int 95 cnclose(dev, flag, mode, p) 96 dev_t dev; 97 int flag, mode; 98 struct proc *p; 99 { 100 struct vnode *vp; 101 102 if (cn_tab == NULL) 103 return (0); 104 105 /* 106 * If the real console isn't otherwise open, close it. 107 * If it's otherwise open, don't close it, because that'll 108 * screw up others who have it open. 109 */ 110 dev = cn_tab->cn_dev; 111 if (cn_devvp != NULLVP) { 112 /* release our reference to real dev's vnode */ 113 vrele(cn_devvp); 114 cn_devvp = NULLVP; 115 } 116 if (vfinddev(dev, VCHR, &vp) && vcount(vp)) 117 return (0); 118 return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p)); 119 } 120 121 int 122 cnread(dev, uio, flag) 123 dev_t dev; 124 struct uio *uio; 125 int flag; 126 { 127 128 /* 129 * If we would redirect input, punt. This will keep strange 130 * things from happening to people who are using the real 131 * console. Nothing should be using /dev/console for 132 * input (except a shell in single-user mode, but then, 133 * one wouldn't TIOCCONS then). 134 */ 135 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 136 return 0; 137 else if (cn_tab == NULL) 138 return ENXIO; 139 140 dev = cn_tab->cn_dev; 141 return ((*cdevsw[major(dev)].d_read)(dev, uio, flag)); 142 } 143 144 int 145 cnwrite(dev, uio, flag) 146 dev_t dev; 147 struct uio *uio; 148 int flag; 149 { 150 151 /* 152 * Redirect output, if that's appropriate. 153 * If there's no real console, return ENXIO. 154 */ 155 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 156 dev = constty->t_dev; 157 else if (cn_tab == NULL) 158 return ENXIO; 159 else 160 dev = cn_tab->cn_dev; 161 return ((*cdevsw[major(dev)].d_write)(dev, uio, flag)); 162 } 163 164 void 165 cnstop(tp, flag) 166 struct tty *tp; 167 int flag; 168 { 169 170 } 171 172 int 173 cnioctl(dev, cmd, data, flag, p) 174 dev_t dev; 175 u_long cmd; 176 caddr_t data; 177 int flag; 178 struct proc *p; 179 { 180 int error; 181 182 /* 183 * Superuser can always use this to wrest control of console 184 * output from the "virtual" console. 185 */ 186 if (cmd == TIOCCONS && constty != NULL) { 187 error = suser(p->p_ucred, (u_short *) NULL); 188 if (error) 189 return (error); 190 constty = NULL; 191 return (0); 192 } 193 194 /* 195 * Redirect the ioctl, if that's appropriate. 196 * Note that strange things can happen, if a program does 197 * ioctls on /dev/console, then the console is redirected 198 * out from under it. 199 */ 200 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 201 dev = constty->t_dev; 202 else if (cn_tab == NULL) 203 return ENXIO; 204 else 205 dev = cn_tab->cn_dev; 206 return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p)); 207 } 208 209 /*ARGSUSED*/ 210 int 211 cnpoll(dev, events, p) 212 dev_t dev; 213 int events; 214 struct proc *p; 215 { 216 217 /* 218 * Redirect the ioctl, if that's appropriate. 219 * I don't want to think of the possible side effects 220 * of console redirection here. 221 */ 222 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 223 dev = constty->t_dev; 224 else if (cn_tab == NULL) 225 return ENXIO; 226 else 227 dev = cn_tab->cn_dev; 228 return ((*cdevsw[major(dev)].d_poll)(dev, events, p)); 229 } 230 231 int 232 cngetc() 233 { 234 235 if (cn_tab == NULL) 236 return (0); 237 return ((*cn_tab->cn_getc)(cn_tab->cn_dev)); 238 } 239 240 void 241 cnputc(c) 242 register int c; 243 { 244 245 if (cn_tab == NULL) 246 return; 247 248 if (c) { 249 (*cn_tab->cn_putc)(cn_tab->cn_dev, c); 250 if (c == '\n') 251 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r'); 252 } 253 } 254 255 void 256 cnpollc(on) 257 int on; 258 { 259 static int refcount = 0; 260 261 if (cn_tab == NULL) 262 return; 263 if (!on) 264 --refcount; 265 if (refcount == 0) 266 (*cn_tab->cn_pollc)(cn_tab->cn_dev, on); 267 if (on) 268 ++refcount; 269 } 270 271 void 272 nullcnpollc(dev, on) 273 dev_t dev; 274 int on; 275 { 276 277 } 278
Indexes created Tue Sep 23 07:09:52 GMT 2025