1e737f33a0
It's guaranteed that the `name' variable always contains a string of the form pty[l‐sL‐S][0‐9a‐v], but I'd rather keep the compiler happy (LLVM).
127 lines
3.8 KiB
C
127 lines
3.8 KiB
C
/*-
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* Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
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* All rights reserved.
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*
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* Portions of this software were developed under sponsorship from Snow
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* B.V., the Netherlands.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/conf.h>
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#include <sys/eventhandler.h>
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#include <sys/fcntl.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <sys/tty.h>
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/*
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* This driver implements a BSD-style compatibility naming scheme for
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* the pts(4) driver. We just call into pts(4) to create the actual PTY.
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* To make sure we don't use the same PTY multiple times, we abuse
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* si_drv1 inside the cdev to mark whether the PTY is in use.
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*/
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static unsigned int pty_warningcnt = 10;
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SYSCTL_UINT(_kern, OID_AUTO, tty_pty_warningcnt, CTLFLAG_RW,
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&pty_warningcnt, 0,
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"Warnings that will be triggered upon PTY allocation");
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static int
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ptydev_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp)
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{
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int error;
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char name[6]; /* "ttyXX" */
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if (!atomic_cmpset_ptr((uintptr_t *)&dev->si_drv1, 0, 1))
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return (EBUSY);
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/* Generate device name and create PTY. */
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strcpy(name, devtoname(dev));
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name[0] = 't';
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error = pts_alloc_external(fflags & (FREAD|FWRITE), td, fp, dev, name);
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if (error != 0) {
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destroy_dev_sched(dev);
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return (error);
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}
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/* Raise a warning when a legacy PTY has been allocated. */
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if (pty_warningcnt > 0) {
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pty_warningcnt--;
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printf("pid %d (%s) is using legacy pty devices%s\n",
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td->td_proc->p_pid, td->td_name,
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pty_warningcnt ? "" : " - not logging anymore");
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}
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return (0);
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}
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static struct cdevsw ptydev_cdevsw = {
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.d_version = D_VERSION,
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.d_fdopen = ptydev_fdopen,
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.d_name = "ptydev",
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};
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static void
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pty_clone(void *arg, struct ucred *cr, char *name, int namelen,
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struct cdev **dev)
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{
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/* Cloning is already satisfied. */
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if (*dev != NULL)
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return;
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/* Only catch /dev/ptyXX. */
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if (namelen != 5 || bcmp(name, "pty", 3) != 0)
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return;
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/* Only catch /dev/pty[l-sL-S]X. */
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if (!(name[3] >= 'l' && name[3] <= 's') &&
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!(name[3] >= 'L' && name[3] <= 'S'))
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return;
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/* Only catch /dev/pty[l-sL-S][0-9a-v]. */
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if (!(name[4] >= '0' && name[4] <= '9') &&
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!(name[4] >= 'a' && name[4] <= 'v'))
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return;
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/* Create the controller device node. */
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*dev = make_dev_credf(MAKEDEV_REF, &ptydev_cdevsw, 0,
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NULL, UID_ROOT, GID_WHEEL, 0666, "%s", name);
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}
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static void
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pty_init(void *unused)
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{
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EVENTHANDLER_REGISTER(dev_clone, pty_clone, 0, 1000);
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}
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SYSINIT(pty, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pty_init, NULL);
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