/* * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * Indirect driver for console * * The purpose of this driver is to provide a device node indirection for * the console device, which can be any tty class device. It does this by * externalizing a global pointer "constty", which is then pointed at the * console tty device. * * The default for this pointer is uninitialized; when it is NULL, we fall * back to the "km" device, which is a tty BSD wrapper device for the * Platform Expert console device. When it is non-NULL, we call through * to the tty device device instead. * * The registration for this device node is static, and the devfs init * code does not externalize a named device for it, to avoid software * seeing the device and trying to open it. * * The upshot of this is that the console driver should not be set as your * controlling tty, since you will get a reference to a device which does * not have an actual device node in /dev, so its name cannot be looked up. */ #include #include #include #include #include #include #include #include struct tty *_constty; /* current console device */ static LCK_GRP_DECLARE(constty_lock_grp, "constty"); static LCK_MTX_DECLARE(_constty_lock, &constty_lock_grp); struct tty * copy_constty(void) { struct tty *result = NULL; lck_mtx_lock(&_constty_lock); if (_constty != NULL) { ttyhold(_constty); result = _constty; } lck_mtx_unlock(&_constty_lock); return result; } struct tty * set_constty(struct tty *new_tty) { struct tty *old_tty = NULL; lck_mtx_lock(&_constty_lock); old_tty = _constty; _constty = new_tty; if (_constty) { ttyhold(_constty); } lck_mtx_unlock(&_constty_lock); return old_tty; } /* * The km driver supplied the default console device for the systems * (usually a raw frame buffer driver, but potentially a serial driver). */ extern struct tty *km_tty[1]; /* * cdevsw[] entries for the console device driver */ int cnopen(__unused dev_t dev, int flag, int devtype, proc_t pp); int cnclose(__unused dev_t dev, int flag, int mode, proc_t pp); int cnread(__unused dev_t dev, struct uio *uio, int ioflag); int cnwrite(__unused dev_t dev, struct uio *uio, int ioflag); int cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flg, proc_t p); int cnselect(__unused dev_t dev, int flag, void * wql, proc_t p); int cnopen(__unused dev_t dev, int flag, int devtype, struct proc *pp) { int error; struct tty *constty = copy_constty(); if (constty) { dev = constty->t_dev; } else { dev = km_tty[0]->t_dev; } error = (*cdevsw[major(dev)].d_open)(dev, flag, devtype, pp); if (constty != NULL) { ttyfree(constty); } return error; } int cnclose(__unused dev_t dev, int flag, int mode, struct proc *pp) { int error; struct tty *constty = copy_constty(); if (constty) { dev = constty->t_dev; } else { dev = km_tty[0]->t_dev; } error = (*cdevsw[major(dev)].d_close)(dev, flag, mode, pp); if (constty != NULL) { ttyfree(constty); } return error; } int cnread(__unused dev_t dev, struct uio *uio, int ioflag) { int error; struct tty *constty = copy_constty(); if (constty) { dev = constty->t_dev; } else { dev = km_tty[0]->t_dev; } error = (*cdevsw[major(dev)].d_read)(dev, uio, ioflag); if (constty != NULL) { ttyfree(constty); } return error; } int cnwrite(__unused dev_t dev, struct uio *uio, int ioflag) { int error; struct tty *constty = copy_constty(); if (constty) { dev = constty->t_dev; } else { dev = km_tty[0]->t_dev; } error = (*cdevsw[major(dev)].d_write)(dev, uio, ioflag); if (constty != NULL) { ttyfree(constty); } return error; } int cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p) { int error; struct tty *constty = copy_constty(); if (constty) { dev = constty->t_dev; } else { dev = km_tty[0]->t_dev; } #if 0 /* * Superuser can always use this to wrest control of console * output from the "virtual" console. * * XXX Unfortunately, this code doesn't do what the author thougt * XXX it did; use of the console device, a TIOCCONS would always * XXX disassociate the console from a virtual terminal and send * XXX it back to the fake tty. */ if ((unsigned) cmd == TIOCCONS && constty) { int error = proc_suser(p); if (!error) { constty = NULL; } return error; } #endif /* 0 */ error = (*cdevsw[major(dev)].d_ioctl)(dev, cmd, addr, flag, p); if (constty != NULL) { ttyfree(constty); } return error; } int cnselect(__unused dev_t dev, int flag, void *wql, struct proc *p) { int error; struct tty *constty = copy_constty(); if (constty) { dev = constty->t_dev; } else { dev = km_tty[0]->t_dev; } error = (*cdevsw[major(dev)].d_select)(dev, flag, wql, p); if (constty != NULL) { ttyfree(constty); } return error; }