cons.c revision 1.32
1 /* $NetBSD: cons.c,v 1.32 1996/09/07 12:40:54 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 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 (cn_devvp == NULLVP) { 79 /* try to get a reference on its vnode, but fail silently */ 80 cdevvp(dev, &cn_devvp); 81 } 82 return ((*cdevsw[major(dev)].d_open)(dev, flag, mode, p)); 83 } 84 85 int 86 cnclose(dev, flag, mode, p) 87 dev_t dev; 88 int flag, mode; 89 struct proc *p; 90 { 91 struct vnode *vp; 92 93 if (cn_tab == NULL) 94 return (0); 95 96 /* 97 * If the real console isn't otherwise open, close it. 98 * If it's otherwise open, don't close it, because that'll 99 * screw up others who have it open. 100 */ 101 dev = cn_tab->cn_dev; 102 if (cn_devvp != NULLVP) { 103 /* release our reference to real dev's vnode */ 104 vrele(cn_devvp); 105 cn_devvp = NULLVP; 106 } 107 if (vfinddev(dev, VCHR, &vp) && vcount(vp)) 108 return (0); 109 return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p)); 110 } 111 112 int 113 cnread(dev, uio, flag) 114 dev_t dev; 115 struct uio *uio; 116 int flag; 117 { 118 119 /* 120 * If we would redirect input, punt. This will keep strange 121 * things from happening to people who are using the real 122 * console. Nothing should be using /dev/console for 123 * input (except a shell in single-user mode, but then, 124 * one wouldn't TIOCCONS then). 125 */ 126 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 127 return 0; 128 else if (cn_tab == NULL) 129 return ENXIO; 130 131 dev = cn_tab->cn_dev; 132 return ((*cdevsw[major(dev)].d_read)(dev, uio, flag)); 133 } 134 135 int 136 cnwrite(dev, uio, flag) 137 dev_t dev; 138 struct uio *uio; 139 int flag; 140 { 141 142 /* 143 * Redirect output, if that's appropriate. 144 * If there's no real console, return ENXIO. 145 */ 146 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 147 dev = constty->t_dev; 148 else if (cn_tab == NULL) 149 return ENXIO; 150 else 151 dev = cn_tab->cn_dev; 152 return ((*cdevsw[major(dev)].d_write)(dev, uio, flag)); 153 } 154 155 void 156 cnstop(tp, flag) 157 struct tty *tp; 158 int flag; 159 { 160 161 } 162 163 int 164 cnioctl(dev, cmd, data, flag, p) 165 dev_t dev; 166 u_long cmd; 167 caddr_t data; 168 int flag; 169 struct proc *p; 170 { 171 int error; 172 173 /* 174 * Superuser can always use this to wrest control of console 175 * output from the "virtual" console. 176 */ 177 if (cmd == TIOCCONS && constty != NULL) { 178 error = suser(p->p_ucred, (u_short *) NULL); 179 if (error) 180 return (error); 181 constty = NULL; 182 return (0); 183 } 184 185 /* 186 * Redirect the ioctl, if that's appropriate. 187 * Note that strange things can happen, if a program does 188 * ioctls on /dev/console, then the console is redirected 189 * out from under it. 190 */ 191 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 192 dev = constty->t_dev; 193 else if (cn_tab == NULL) 194 return ENXIO; 195 else 196 dev = cn_tab->cn_dev; 197 return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p)); 198 } 199 200 /*ARGSUSED*/ 201 int 202 cnpoll(dev, events, p) 203 dev_t dev; 204 int events; 205 struct proc *p; 206 { 207 208 /* 209 * Redirect the ioctl, if that's appropriate. 210 * I don't want to think of the possible side effects 211 * of console redirection here. 212 */ 213 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 214 dev = constty->t_dev; 215 else if (cn_tab == NULL) 216 return ENXIO; 217 else 218 dev = cn_tab->cn_dev; 219 return ((*cdevsw[major(dev)].d_poll)(dev, events, p)); 220 } 221 222 int 223 cngetc() 224 { 225 226 if (cn_tab == NULL) 227 return (0); 228 return ((*cn_tab->cn_getc)(cn_tab->cn_dev)); 229 } 230 231 void 232 cnputc(c) 233 register int c; 234 { 235 236 if (cn_tab == NULL) 237 return; 238 239 if (c) { 240 (*cn_tab->cn_putc)(cn_tab->cn_dev, c); 241 if (c == '\n') 242 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r'); 243 } 244 } 245 246 void 247 cnpollc(on) 248 int on; 249 { 250 static int refcount = 0; 251 252 if (cn_tab == NULL) 253 return; 254 if (!on) 255 --refcount; 256 if (refcount == 0) 257 (*cn_tab->cn_pollc)(cn_tab->cn_dev, on); 258 if (on) 259 ++refcount; 260 } 261 262 void 263 nullcnpollc(dev, on) 264 dev_t dev; 265 int on; 266 { 267 268 } 269
Indexes created Wed Sep 24 05:09:52 GMT 2025