cons.c revision 1.23
1 /* $NetBSD: cons.c,v 1.23 1994/12/14 19:09:13 mycroft 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 extern struct consdev constab[]; 59 60 struct tty *constty = NULL; /* virtual console output device */ 61 struct consdev *cn_tab; /* physical console device info */ 62 struct vnode *cn_devvp; /* vnode for underlying device. */ 63 64 65 void 66 cninit() 67 { 68 register struct consdev *cp; 69 70 /* 71 * Collect information about all possible consoles 72 * and find the one with highest priority 73 */ 74 for (cp = constab; cp->cn_probe; cp++) { 75 (*cp->cn_probe)(cp); 76 if (cp->cn_pri > CN_DEAD && 77 (cn_tab == NULL || cp->cn_pri > cn_tab->cn_pri)) 78 cn_tab = cp; 79 } 80 /* 81 * No console, we can handle it 82 */ 83 if ((cp = cn_tab) == NULL) 84 return; 85 /* 86 * Turn on console 87 */ 88 (*cp->cn_init)(cp); 89 } 90 91 int 92 cnopen(dev, flag, mode, p) 93 dev_t dev; 94 int flag, mode; 95 struct proc *p; 96 { 97 98 if (cn_tab == NULL) 99 return (0); 100 101 /* 102 * always open the 'real' console device, so we don't get nailed 103 * later. This follows normal device semantics; they always get 104 * open() calls. 105 */ 106 dev = cn_tab->cn_dev; 107 if (cn_devvp == NULLVP) { 108 /* try to get a reference on its vnode, but fail silently */ 109 cdevvp(dev, &cn_devvp); 110 } 111 return ((*cdevsw[major(dev)].d_open)(dev, flag, mode, p)); 112 } 113 114 int 115 cnclose(dev, flag, mode, p) 116 dev_t dev; 117 int flag, mode; 118 struct proc *p; 119 { 120 struct vnode *vp; 121 122 if (cn_tab == NULL) 123 return (0); 124 125 /* 126 * If the real console isn't otherwise open, close it. 127 * If it's otherwise open, don't close it, because that'll 128 * screw up others who have it open. 129 */ 130 dev = cn_tab->cn_dev; 131 if (cn_devvp != NULLVP) { 132 /* release our reference to real dev's vnode */ 133 vrele(cn_devvp); 134 cn_devvp = NULLVP; 135 } 136 if (vfinddev(dev, VCHR, &vp) && vcount(vp)) 137 return (0); 138 return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p)); 139 } 140 141 int 142 cnread(dev, uio, flag) 143 dev_t dev; 144 struct uio *uio; 145 { 146 147 /* 148 * If we would redirect input, punt. This will keep strange 149 * things from happening to people who are using the real 150 * console. Nothing should be using /dev/console for 151 * input (except a shell in single-user mode, but then, 152 * one wouldn't TIOCCONS then). 153 */ 154 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 155 return 0; 156 else if (cn_tab == NULL) 157 return ENXIO; 158 159 dev = cn_tab->cn_dev; 160 return ((*cdevsw[major(dev)].d_read)(dev, uio, flag)); 161 } 162 163 int 164 cnwrite(dev, uio, flag) 165 dev_t dev; 166 struct uio *uio; 167 { 168 169 /* 170 * Redirect output, if that's appropriate. 171 * If there's no real console, return ENXIO. 172 */ 173 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 174 dev = constty->t_dev; 175 else if (cn_tab == NULL) 176 return ENXIO; 177 else 178 dev = cn_tab->cn_dev; 179 return ((*cdevsw[major(dev)].d_write)(dev, uio, flag)); 180 } 181 182 int 183 cnioctl(dev, cmd, data, flag, p) 184 dev_t dev; 185 u_long cmd; 186 caddr_t data; 187 int flag; 188 struct proc *p; 189 { 190 int error; 191 192 /* 193 * Superuser can always use this to wrest control of console 194 * output from the "virtual" console. 195 */ 196 if (cmd == TIOCCONS && constty != NULL) { 197 error = suser(p->p_ucred, (u_short *) NULL); 198 if (error) 199 return (error); 200 constty = NULL; 201 return (0); 202 } 203 204 /* 205 * Redirect the ioctl, if that's appropriate. 206 * Note that strange things can happen, if a program does 207 * ioctls on /dev/console, then the console is redirected 208 * out from under it. 209 */ 210 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 211 dev = constty->t_dev; 212 else if (cn_tab == NULL) 213 return ENXIO; 214 else 215 dev = cn_tab->cn_dev; 216 return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p)); 217 } 218 219 /*ARGSUSED*/ 220 int 221 cnselect(dev, rw, p) 222 dev_t dev; 223 int rw; 224 struct proc *p; 225 { 226 227 /* 228 * Redirect the ioctl, if that's appropriate. 229 * I don't want to think of the possible side effects 230 * of console redirection here. 231 */ 232 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 233 dev = constty->t_dev; 234 else if (cn_tab == NULL) 235 return ENXIO; 236 else 237 dev = cn_tab->cn_dev; 238 return (ttselect(cn_tab->cn_dev, rw, p)); 239 } 240 241 int 242 cngetc() 243 { 244 245 if (cn_tab == NULL) 246 return (0); 247 return ((*cn_tab->cn_getc)(cn_tab->cn_dev)); 248 } 249 250 int 251 cnputc(c) 252 register int c; 253 { 254 255 if (cn_tab == NULL) 256 return; 257 if (c) { 258 (*cn_tab->cn_putc)(cn_tab->cn_dev, c); 259 if (c == '\n') 260 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r'); 261 } 262 } 263 264 void 265 cnpollc(on) 266 int on; 267 { 268 static int refcount = 0; 269 270 if (cn_tab == NULL) 271 return; 272 if (!on) 273 --refcount; 274 if (refcount == 0) 275 (*cn_tab->cn_pollc)(cn_tab->cn_dev, on); 276 if (on) 277 ++refcount; 278 } 279 280 void 281 nullcnpollc(on) 282 int on; 283 { 284 285 } 286
Indexes created Tue Sep 23 07:09:52 GMT 2025