1 /* $NetBSD: cons.c,v 1.18 1994/06/29 06:31:32 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 if (cn_tab == NULL) 98 return (0); 99 100 /* 101 * always open the 'real' console device, so we don't get nailed 102 * later. This follows normal device semantics; they always get 103 * open() calls. 104 */ 105 dev = cn_tab->cn_dev; 106 if (cn_devvp == NULLVP) { 107 /* try to get a reference on its vnode, but fail silently */ 108 cdevvp(dev, &cn_devvp); 109 } 110 return ((*cdevsw[major(dev)].d_open)(dev, flag, mode, p)); 111 } 112 113 int 114 cnclose(dev, flag, mode, p) 115 dev_t dev; 116 int flag, mode; 117 struct proc *p; 118 { 119 struct vnode *vp; 120 121 if (cn_tab == NULL) 122 return (0); 123 124 /* 125 * If the real console isn't otherwise open, close it. 126 * If it's otherwise open, don't close it, because that'll 127 * screw up others who have it open. 128 */ 129 dev = cn_tab->cn_dev; 130 if (cn_devvp != NULLVP) { 131 /* release our reference to real dev's vnode */ 132 vrele(cn_devvp); 133 cn_devvp = NULLVP; 134 } 135 if (vfinddev(dev, VCHR, &vp) && vcount(vp)) 136 return (0); 137 return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p)); 138 } 139 140 int 141 cnread(dev, uio, flag) 142 dev_t dev; 143 struct uio *uio; 144 { 145 /* 146 * If we would redirect input, punt. This will keep strange 147 * things from happening to people who are using the real 148 * console. Nothing should be using /dev/console for 149 * input (except a shell in single-user mode, but then, 150 * one wouldn't TIOCCONS then). 151 */ 152 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 153 return 0; 154 else if (cn_tab == NULL) 155 return ENXIO; 156 157 dev = cn_tab->cn_dev; 158 return ((*cdevsw[major(dev)].d_read)(dev, uio, flag)); 159 } 160 161 int 162 cnwrite(dev, uio, flag) 163 dev_t dev; 164 struct uio *uio; 165 { 166 /* 167 * Redirect output, if that's appropriate. 168 * If there's no real console, return ENXIO. 169 */ 170 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 171 dev = constty->t_dev; 172 else if (cn_tab == NULL) 173 return ENXIO; 174 else 175 dev = cn_tab->cn_dev; 176 return ((*cdevsw[major(dev)].d_write)(dev, uio, flag)); 177 } 178 179 int 180 cnioctl(dev, cmd, data, flag, p) 181 dev_t dev; 182 caddr_t data; 183 struct proc *p; 184 { 185 int error; 186 187 /* 188 * Superuser can always use this to wrest control of console 189 * output from the "virtual" console. 190 */ 191 if (cmd == TIOCCONS && constty != NULL) { 192 error = suser(p->p_ucred, (u_short *) NULL); 193 if (error) 194 return (error); 195 constty = NULL; 196 return (0); 197 } 198 199 /* 200 * Redirect the ioctl, if that's appropriate. 201 * Note that strange things can happen, if a program does 202 * ioctls on /dev/console, then the console is redirected 203 * out from under it. 204 */ 205 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 206 dev = constty->t_dev; 207 else if (cn_tab == NULL) 208 return ENXIO; 209 else 210 dev = cn_tab->cn_dev; 211 return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p)); 212 } 213 214 /*ARGSUSED*/ 215 int 216 cnselect(dev, rw, p) 217 dev_t dev; 218 int rw; 219 struct proc *p; 220 { 221 /* 222 * Redirect the ioctl, if that's appropriate. 223 * I don't want to think of the possible side effects 224 * of console redirection here. 225 */ 226 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 227 dev = constty->t_dev; 228 else if (cn_tab == NULL) 229 return ENXIO; 230 else 231 dev = cn_tab->cn_dev; 232 return (ttselect(cn_tab->cn_dev, rw, p)); 233 } 234 235 int 236 cngetc() 237 { 238 if (cn_tab == NULL) 239 return (0); 240 return ((*cn_tab->cn_getc)(cn_tab->cn_dev)); 241 } 242 243 int 244 cnputc(c) 245 register int c; 246 { 247 if (cn_tab == NULL) 248 return; 249 if (c) { 250 (*cn_tab->cn_putc)(cn_tab->cn_dev, c); 251 if (c == '\n') 252 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r'); 253 } 254 } 255