Annotation of sys/dev/cons.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: cons.c,v 1.18 2007/06/17 18:50:58 jasper Exp $ */
! 2: /* $NetBSD: cons.c,v 1.30 1996/04/08 19:57:30 jonathan Exp $ */
! 3:
! 4: /*
! 5: * Copyright (c) 1988 University of Utah.
! 6: * Copyright (c) 1990, 1993
! 7: * The Regents of the University of California. All rights reserved.
! 8: *
! 9: * This code is derived from software contributed to Berkeley by
! 10: * the Systems Programming Group of the University of Utah Computer
! 11: * Science Department.
! 12: *
! 13: * Redistribution and use in source and binary forms, with or without
! 14: * modification, are permitted provided that the following conditions
! 15: * are met:
! 16: * 1. Redistributions of source code must retain the above copyright
! 17: * notice, this list of conditions and the following disclaimer.
! 18: * 2. Redistributions in binary form must reproduce the above copyright
! 19: * notice, this list of conditions and the following disclaimer in the
! 20: * documentation and/or other materials provided with the distribution.
! 21: * 3. Neither the name of the University nor the names of its contributors
! 22: * may be used to endorse or promote products derived from this software
! 23: * without specific prior written permission.
! 24: *
! 25: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 26: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 27: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 28: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 29: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 30: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 31: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 32: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 33: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 34: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 35: * SUCH DAMAGE.
! 36: *
! 37: * from: Utah $Hdr: cons.c 1.7 92/01/21$
! 38: *
! 39: * @(#)cons.c 8.2 (Berkeley) 1/12/94
! 40: */
! 41:
! 42: #include <sys/param.h>
! 43: #include <sys/systm.h>
! 44: #include <sys/proc.h>
! 45: #include <sys/user.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: #include <sys/poll.h>
! 53:
! 54: #include <dev/cons.h>
! 55:
! 56: struct tty *constty = NULL; /* virtual console output device */
! 57: struct consdev *cn_tab; /* physical console device info */
! 58: struct vnode *cn_devvp; /* vnode for underlying device. */
! 59:
! 60: int
! 61: cnopen(dev_t dev, int flag, int mode, struct proc *p)
! 62: {
! 63: dev_t cndev;
! 64:
! 65: if (cn_tab == NULL)
! 66: return (0);
! 67:
! 68: /*
! 69: * always open the 'real' console device, so we don't get nailed
! 70: * later. This follows normal device semantics; they always get
! 71: * open() calls.
! 72: */
! 73: cndev = cn_tab->cn_dev;
! 74: if (cndev == NODEV)
! 75: return (ENXIO);
! 76: #ifdef DIAGNOSTIC
! 77: if (cndev == dev)
! 78: panic("cnopen: recursive");
! 79: #endif
! 80: if (cn_devvp == NULLVP) {
! 81: /* try to get a reference on its vnode, but fail silently */
! 82: cdevvp(cndev, &cn_devvp);
! 83: }
! 84: return ((*cdevsw[major(cndev)].d_open)(cndev, flag, mode, p));
! 85: }
! 86:
! 87: int
! 88: cnclose(dev_t dev, int flag, int mode, struct proc *p)
! 89: {
! 90: struct vnode *vp;
! 91:
! 92: if (cn_tab == NULL)
! 93: return (0);
! 94:
! 95: /*
! 96: * If the real console isn't otherwise open, close it.
! 97: * If it's otherwise open, don't close it, because that'll
! 98: * screw up others who have it open.
! 99: */
! 100: dev = cn_tab->cn_dev;
! 101: if (cn_devvp != NULLVP) {
! 102: /* release our reference to real dev's vnode */
! 103: vrele(cn_devvp);
! 104: cn_devvp = NULLVP;
! 105: }
! 106: if (vfinddev(dev, VCHR, &vp) && vcount(vp))
! 107: return (0);
! 108: return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p));
! 109: }
! 110:
! 111: int
! 112: cnread(dev_t dev, struct uio *uio, int flag)
! 113: {
! 114:
! 115: /*
! 116: * If we would redirect input, punt. This will keep strange
! 117: * things from happening to people who are using the real
! 118: * console. Nothing should be using /dev/console for
! 119: * input (except a shell in single-user mode, but then,
! 120: * one wouldn't TIOCCONS then).
! 121: */
! 122: if (constty != NULL)
! 123: return 0;
! 124: else if (cn_tab == NULL)
! 125: return ENXIO;
! 126:
! 127: dev = cn_tab->cn_dev;
! 128: return ((*cdevsw[major(dev)].d_read)(dev, uio, flag));
! 129: }
! 130:
! 131: int
! 132: cnwrite(dev_t dev, struct uio *uio, int flag)
! 133: {
! 134:
! 135: /*
! 136: * Redirect output, if that's appropriate.
! 137: * If there's no real console, return ENXIO.
! 138: */
! 139: if (constty != NULL)
! 140: dev = constty->t_dev;
! 141: else if (cn_tab == NULL)
! 142: return ENXIO;
! 143: else
! 144: dev = cn_tab->cn_dev;
! 145: return ((*cdevsw[major(dev)].d_write)(dev, uio, flag));
! 146: }
! 147:
! 148: int
! 149: cnstop(struct tty *tp, int flag)
! 150: {
! 151: return (0);
! 152: }
! 153:
! 154: int
! 155: cnioctl(dev_t dev, u_long cmd, caddr_t data, int flag,
! 156: struct proc *p)
! 157: {
! 158: int error;
! 159:
! 160: /*
! 161: * Superuser can always use this to wrest control of console
! 162: * output from the "virtual" console.
! 163: */
! 164: if (cmd == TIOCCONS && constty != NULL) {
! 165: error = suser(p, SUSER_NOACCT);
! 166: if (error)
! 167: return (error);
! 168: constty = NULL;
! 169: return (0);
! 170: }
! 171:
! 172: /*
! 173: * Redirect the ioctl, if that's appropriate.
! 174: * Note that strange things can happen, if a program does
! 175: * ioctls on /dev/console, then the console is redirected
! 176: * out from under it.
! 177: */
! 178: if (constty != NULL)
! 179: dev = constty->t_dev;
! 180: else if (cn_tab == NULL)
! 181: return ENXIO;
! 182: else
! 183: dev = cn_tab->cn_dev;
! 184: return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p));
! 185: }
! 186:
! 187: /*ARGSUSED*/
! 188: int
! 189: cnpoll(dev_t dev, int rw, struct proc *p)
! 190: {
! 191:
! 192: /*
! 193: * Redirect the poll, if that's appropriate.
! 194: * I don't want to think of the possible side effects
! 195: * of console redirection here.
! 196: */
! 197: if (constty != NULL)
! 198: dev = constty->t_dev;
! 199: else if (cn_tab == NULL)
! 200: return POLLERR;
! 201: else
! 202: dev = cn_tab->cn_dev;
! 203: return (ttpoll(cn_tab->cn_dev, rw, p));
! 204: }
! 205:
! 206:
! 207: int
! 208: cnkqfilter(dev_t dev, struct knote *kn)
! 209: {
! 210:
! 211: /*
! 212: * Redirect output, if that's appropriate.
! 213: * If there's no real console, return 1.
! 214: */
! 215: if (constty != NULL)
! 216: dev = constty->t_dev;
! 217: else if (cn_tab == NULL)
! 218: return (1);
! 219: else
! 220: dev = cn_tab->cn_dev;
! 221: if (cdevsw[major(dev)].d_flags & D_KQFILTER)
! 222: return ((*cdevsw[major(dev)].d_kqfilter)(dev, kn));
! 223: return (1);
! 224: }
! 225:
! 226: int
! 227: cngetc(void)
! 228: {
! 229:
! 230: if (cn_tab == NULL)
! 231: return (0);
! 232: return ((*cn_tab->cn_getc)(cn_tab->cn_dev));
! 233: }
! 234:
! 235: void
! 236: cnputc(int c)
! 237: {
! 238:
! 239: if (cn_tab == NULL)
! 240: return;
! 241:
! 242: if (c) {
! 243: (*cn_tab->cn_putc)(cn_tab->cn_dev, c);
! 244: if (c == '\n')
! 245: (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
! 246: }
! 247: }
! 248:
! 249: void
! 250: cnpollc(int on)
! 251: {
! 252: static int refcount = 0;
! 253:
! 254: if (cn_tab == NULL)
! 255: return;
! 256: if (!on)
! 257: --refcount;
! 258: if (refcount == 0)
! 259: (*cn_tab->cn_pollc)(cn_tab->cn_dev, on);
! 260: if (on)
! 261: ++refcount;
! 262: }
! 263:
! 264: void
! 265: nullcnpollc(dev_t dev, int on)
! 266: {
! 267:
! 268: }
! 269:
! 270: void
! 271: cnbell(u_int pitch, u_int period, u_int volume)
! 272: {
! 273: if (cn_tab == NULL || cn_tab->cn_bell == NULL)
! 274: return;
! 275:
! 276: (*cn_tab->cn_bell)(cn_tab->cn_dev, pitch, period, volume);
! 277: }
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