1 /* 2 * Copyright (c) 1988 University of Utah. 3 * Copyright (c) 1991 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the Systems Programming Group of the University of Utah Computer 8 * Science Department. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)cons.c 7.2 (Berkeley) 5/9/91 39 * $Id: cons.c,v 1.15 1994/04/11 21:53:54 cgd Exp $ 40 */ 41 42 #include <sys/param.h> 43 #include <sys/proc.h> 44 #include <sys/user.h> 45 #include <sys/systm.h> 46 #include <sys/buf.h> 47 #include <sys/ioctl.h> 48 #include <sys/tty.h> 49 #include <sys/file.h> 50 #include <sys/conf.h> 51 #include <sys/vnode.h> 52 53 #include <dev/cons.h> 54 55 extern struct consdev constab[]; 56 57 struct tty *constty = NULL; /* virtual console output device */ 58 struct consdev *cn_tab; /* physical console device info */ 59 struct vnode *cn_devvp; /* vnode for underlying device. */ 60 61 62 void 63 cninit() 64 { 65 register struct consdev *cp; 66 67 /* 68 * Collect information about all possible consoles 69 * and find the one with highest priority 70 */ 71 for (cp = constab; cp->cn_probe; cp++) { 72 (*cp->cn_probe)(cp); 73 if (cp->cn_pri > CN_DEAD && 74 (cn_tab == NULL || cp->cn_pri > cn_tab->cn_pri)) 75 cn_tab = cp; 76 } 77 /* 78 * No console, we can handle it 79 */ 80 if ((cp = cn_tab) == NULL) 81 return; 82 /* 83 * Turn on console 84 */ 85 (*cp->cn_init)(cp); 86 } 87 88 int 89 cnopen(dev, flag, mode, p) 90 dev_t dev; 91 int flag, mode; 92 struct proc *p; 93 { 94 if (cn_tab == NULL) 95 return (0); 96 97 /* 98 * always open the 'real' console device, so we don't get nailed 99 * later. This follows normal device semantics; they always get 100 * open() calls. 101 */ 102 dev = cn_tab->cn_dev; 103 if (cn_devvp == NULLVP) { 104 /* try to get a reference on its vnode, but fail silently */ 105 cdevvp(dev, &cn_devvp); 106 } 107 return ((*cdevsw[major(dev)].d_open)(dev, flag, mode, p)); 108 } 109 110 int 111 cnclose(dev, flag, mode, p) 112 dev_t dev; 113 int flag, mode; 114 struct proc *p; 115 { 116 struct vnode *vp; 117 118 if (cn_tab == NULL) 119 return (0); 120 121 /* 122 * If the real console isn't otherwise open, close it. 123 * If it's otherwise open, don't close it, because that'll 124 * screw up others who have it open. 125 */ 126 dev = cn_tab->cn_dev; 127 if (cn_devvp != NULLVP) { 128 /* release our reference to real dev's vnode */ 129 vrele(cn_devvp); 130 cn_devvp = NULLVP; 131 } 132 if ((vfinddev(dev, VCHR, &vp) == 0) && vcount(vp)) 133 return (0); 134 return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p)); 135 } 136 137 int 138 cnread(dev, uio, flag) 139 dev_t dev; 140 struct uio *uio; 141 { 142 /* 143 * If we would redirect input, punt. This will keep strange 144 * things from happening to people who are using the real 145 * console. Nothing should be using /dev/console for 146 * input (except a shell in single-user mode, but then, 147 * one wouldn't TIOCCONS then). 148 */ 149 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 150 return 0; 151 else if (cn_tab == NULL) 152 return ENXIO; 153 154 dev = cn_tab->cn_dev; 155 return ((*cdevsw[major(dev)].d_read)(dev, uio, flag)); 156 } 157 158 int 159 cnwrite(dev, uio, flag) 160 dev_t dev; 161 struct uio *uio; 162 { 163 /* 164 * Redirect output, if that's appropriate. 165 * If there's no real console, return ENXIO. 166 */ 167 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 168 dev = constty->t_dev; 169 else if (cn_tab == NULL) 170 return ENXIO; 171 else 172 dev = cn_tab->cn_dev; 173 return ((*cdevsw[major(dev)].d_write)(dev, uio, flag)); 174 } 175 176 int 177 cnioctl(dev, cmd, data, flag, p) 178 dev_t dev; 179 caddr_t data; 180 struct proc *p; 181 { 182 int error; 183 184 /* 185 * Superuser can always use this to wrest control of console 186 * output from the "virtual" console. 187 */ 188 if (cmd == TIOCCONS && constty != NULL) { 189 error = suser(p->p_ucred, (u_short *) NULL); 190 if (error) 191 return (error); 192 constty = NULL; 193 return (0); 194 } 195 196 /* 197 * Redirect the ioctl, if that's appropriate. 198 * Note that strange things can happen, if a program does 199 * ioctls on /dev/console, then the console is redirected 200 * out from under it. 201 */ 202 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 203 dev = constty->t_dev; 204 else if (cn_tab == NULL) 205 return ENXIO; 206 else 207 dev = cn_tab->cn_dev; 208 return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p)); 209 } 210 211 /*ARGSUSED*/ 212 int 213 cnselect(dev, rw, p) 214 dev_t dev; 215 int rw; 216 struct proc *p; 217 { 218 /* 219 * Redirect the ioctl, if that's appropriate. 220 * I don't want to think of the possible side effects 221 * of console redirection here. 222 */ 223 if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE)) 224 dev = constty->t_dev; 225 else if (cn_tab == NULL) 226 return ENXIO; 227 else 228 dev = cn_tab->cn_dev; 229 return (ttselect(cn_tab->cn_dev, rw, p)); 230 } 231 232 int 233 cngetc() 234 { 235 if (cn_tab == NULL) 236 return (0); 237 return ((*cn_tab->cn_getc)(cn_tab->cn_dev)); 238 } 239 240 int 241 cnputc(c) 242 register int c; 243 { 244 if (cn_tab == NULL) 245 return; 246 if (c) { 247 (*cn_tab->cn_putc)(cn_tab->cn_dev, c); 248 if (c == '\n') 249 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r'); 250 } 251 } 252