cons.c revision 1.24
1 /* $NetBSD: cons.c,v 1.24 1995/03/24 15:29:46 cgd 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 int flag; 146 { 147 148 /* 149 * If we would redirect input, punt. This will keep strange 150 * things from happening to people who are using the real 151 * console. Nothing should be using /dev/console for 152 * input (except a shell in single-user mode, but then, 153 * one wouldn't TIOCCONS then). 154 */ 155 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 156 return 0; 157 else if (cn_tab == NULL) 158 return ENXIO; 159 160 dev = cn_tab->cn_dev; 161 return ((*cdevsw[major(dev)].d_read)(dev, uio, flag)); 162 } 163 164 int 165 cnwrite(dev, uio, flag) 166 dev_t dev; 167 struct uio *uio; 168 int flag; 169 { 170 171 /* 172 * Redirect output, if that's appropriate. 173 * If there's no real console, return ENXIO. 174 */ 175 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 176 dev = constty->t_dev; 177 else if (cn_tab == NULL) 178 return ENXIO; 179 else 180 dev = cn_tab->cn_dev; 181 return ((*cdevsw[major(dev)].d_write)(dev, uio, flag)); 182 } 183 184 int 185 cnioctl(dev, cmd, data, flag, p) 186 dev_t dev; 187 u_long cmd; 188 caddr_t data; 189 int flag; 190 struct proc *p; 191 { 192 int error; 193 194 /* 195 * Superuser can always use this to wrest control of console 196 * output from the "virtual" console. 197 */ 198 if (cmd == TIOCCONS && constty != NULL) { 199 error = suser(p->p_ucred, (u_short *) NULL); 200 if (error) 201 return (error); 202 constty = NULL; 203 return (0); 204 } 205 206 /* 207 * Redirect the ioctl, if that's appropriate. 208 * Note that strange things can happen, if a program does 209 * ioctls on /dev/console, then the console is redirected 210 * out from under it. 211 */ 212 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 213 dev = constty->t_dev; 214 else if (cn_tab == NULL) 215 return ENXIO; 216 else 217 dev = cn_tab->cn_dev; 218 return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p)); 219 } 220 221 /*ARGSUSED*/ 222 int 223 cnselect(dev, rw, p) 224 dev_t dev; 225 int rw; 226 struct proc *p; 227 { 228 229 /* 230 * Redirect the ioctl, if that's appropriate. 231 * I don't want to think of the possible side effects 232 * of console redirection here. 233 */ 234 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 235 dev = constty->t_dev; 236 else if (cn_tab == NULL) 237 return ENXIO; 238 else 239 dev = cn_tab->cn_dev; 240 return (ttselect(cn_tab->cn_dev, rw, p)); 241 } 242 243 int 244 cngetc() 245 { 246 247 if (cn_tab == NULL) 248 return (0); 249 return ((*cn_tab->cn_getc)(cn_tab->cn_dev)); 250 } 251 252 int 253 cnputc(c) 254 register int c; 255 { 256 257 if (cn_tab == NULL) 258 return 0; /* XXX should be void */ 259 if (c) { 260 (*cn_tab->cn_putc)(cn_tab->cn_dev, c); 261 if (c == '\n') 262 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r'); 263 } 264 return 0; /* XXX should be void */ 265 } 266 267 void 268 cnpollc(on) 269 int on; 270 { 271 static int refcount = 0; 272 273 if (cn_tab == NULL) 274 return; 275 if (!on) 276 --refcount; 277 if (refcount == 0) 278 (*cn_tab->cn_pollc)(cn_tab->cn_dev, on); 279 if (on) 280 ++refcount; 281 } 282 283 void 284 nullcnpollc(on) 285 int on; 286 { 287 288 } 289
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