388 lines
8.4 KiB
C
388 lines
8.4 KiB
C
/* $NetBSD: tty_ptm.c,v 1.27 2010/06/24 13:03:11 hannken Exp $ */
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/*-
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* Copyright (c) 2004 The NetBSD Foundation, Inc.
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* All rights reserved.
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: tty_ptm.c,v 1.27 2010/06/24 13:03:11 hannken Exp $");
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#include "opt_ptm.h"
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/* pty multiplexor driver /dev/ptm{,x} */
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/ioctl.h>
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#include <sys/proc.h>
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#include <sys/tty.h>
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#include <sys/stat.h>
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#include <sys/file.h>
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#include <sys/uio.h>
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#include <sys/kernel.h>
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#include <sys/vnode.h>
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#include <sys/namei.h>
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#include <sys/signalvar.h>
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#include <sys/filedesc.h>
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#include <sys/conf.h>
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#include <sys/poll.h>
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#include <sys/pty.h>
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#include <sys/kauth.h>
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#include <miscfs/specfs/specdev.h>
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#ifdef DEBUG_PTM
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#define DPRINTF(a) printf a
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#else
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#define DPRINTF(a)
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#endif
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#ifdef NO_DEV_PTM
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const struct cdevsw ptm_cdevsw = {
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noopen, noclose, noread, nowrite, noioctl,
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nostop, notty, nopoll, nommap, nokqfilter, D_TTY
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};
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#else
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static struct ptm_pty *ptm;
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int pts_major, ptc_major;
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static dev_t pty_getfree(void);
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static int pty_alloc_master(struct lwp *, int *, dev_t *);
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static int pty_alloc_slave(struct lwp *, int *, dev_t);
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void ptmattach(int);
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dev_t
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pty_makedev(char ms, int minor)
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{
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return makedev(ms == 't' ? pts_major : ptc_major, minor);
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}
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static dev_t
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pty_getfree(void)
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{
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extern kmutex_t pt_softc_mutex;
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int i;
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mutex_enter(&pt_softc_mutex);
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for (i = 0; i < npty; i++) {
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if (pty_isfree(i, 0))
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break;
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}
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mutex_exit(&pt_softc_mutex);
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return pty_makedev('t', i);
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}
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/*
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* Hacked up version of vn_open. We _only_ handle ptys and only open
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* them with FREAD|FWRITE and never deal with creat or stuff like that.
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*
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* We need it because we have to fake up root credentials to open the pty.
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*/
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int
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pty_vn_open(struct vnode *vp, struct lwp *l)
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{
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int error;
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if (vp->v_type != VCHR) {
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vput(vp);
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return EINVAL;
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}
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error = VOP_OPEN(vp, FREAD|FWRITE, lwp0.l_cred);
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if (error) {
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vput(vp);
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return error;
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}
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vp->v_writecount++;
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return 0;
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}
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static int
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pty_alloc_master(struct lwp *l, int *fd, dev_t *dev)
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{
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int error;
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struct file *fp;
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struct vnode *vp;
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int md;
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if ((error = fd_allocfile(&fp, fd)) != 0) {
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DPRINTF(("fd_allocfile %d\n", error));
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return error;
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}
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retry:
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/* Find and open a free master pty. */
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*dev = pty_getfree();
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md = minor(*dev);
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if ((error = pty_check(md)) != 0) {
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DPRINTF(("pty_check %d\n", error));
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goto bad;
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}
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if (ptm == NULL) {
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DPRINTF(("no ptm\n"));
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error = EOPNOTSUPP;
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goto bad;
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}
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if ((error = (*ptm->allocvp)(ptm, l, &vp, *dev, 'p')) != 0) {
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DPRINTF(("pty_allocvp %d\n", error));
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goto bad;
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}
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if ((error = pty_vn_open(vp, l)) != 0) {
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DPRINTF(("pty_vn_open %d\n", error));
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/*
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* Check if the master open failed because we lost
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* the race to grab it.
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*/
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if (error != EIO)
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goto bad;
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error = !pty_isfree(md, 1);
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DPRINTF(("pty_isfree %d\n", error));
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if (error)
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goto retry;
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else
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goto bad;
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}
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fp->f_flag = FREAD|FWRITE;
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fp->f_type = DTYPE_VNODE;
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fp->f_ops = &vnops;
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fp->f_data = vp;
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VOP_UNLOCK(vp);
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fd_affix(curproc, fp, *fd);
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return 0;
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bad:
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fd_abort(curproc, fp, *fd);
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return error;
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}
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int
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pty_grant_slave(struct lwp *l, dev_t dev)
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{
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int error;
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struct vnode *vp;
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/*
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* Open the slave.
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* namei -> setattr -> unlock -> revoke -> vrele ->
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* namei -> open -> unlock
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* Three stage rocket:
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* 1. Change the owner and permissions on the slave.
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* 2. Revoke all the users of the slave.
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* 3. open the slave.
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*/
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if (ptm == NULL)
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return EOPNOTSUPP;
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if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0)
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return error;
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if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
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struct vattr vattr;
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(*ptm->getvattr)(ptm, l, &vattr);
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/* Do the VOP_SETATTR() as root. */
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error = VOP_SETATTR(vp, &vattr, lwp0.l_cred);
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if (error) {
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DPRINTF(("setattr %d\n", error));
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VOP_UNLOCK(vp);
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vrele(vp);
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return error;
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}
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}
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VOP_UNLOCK(vp);
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VOP_REVOKE(vp, REVOKEALL);
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/*
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* The vnode is useless after the revoke, we need to get it again.
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*/
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vrele(vp);
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return 0;
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}
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static int
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pty_alloc_slave(struct lwp *l, int *fd, dev_t dev)
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{
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int error;
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struct file *fp;
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struct vnode *vp;
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/* Grab a filedescriptor for the slave */
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if ((error = fd_allocfile(&fp, fd)) != 0) {
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DPRINTF(("fd_allocfile %d\n", error));
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return error;
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}
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if (ptm == NULL) {
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error = EOPNOTSUPP;
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goto bad;
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}
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if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0)
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goto bad;
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if ((error = pty_vn_open(vp, l)) != 0)
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goto bad;
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fp->f_flag = FREAD|FWRITE;
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fp->f_type = DTYPE_VNODE;
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fp->f_ops = &vnops;
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fp->f_data = vp;
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VOP_UNLOCK(vp);
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fd_affix(curproc, fp, *fd);
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return 0;
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bad:
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fd_abort(curproc, fp, *fd);
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return error;
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}
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struct ptm_pty *
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pty_sethandler(struct ptm_pty *nptm)
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{
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struct ptm_pty *optm = ptm;
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ptm = nptm;
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return optm;
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}
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int
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pty_fill_ptmget(struct lwp *l, dev_t dev, int cfd, int sfd, void *data)
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{
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struct ptmget *ptmg = data;
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int error;
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if (ptm == NULL)
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return EOPNOTSUPP;
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ptmg->cfd = cfd == -1 ? minor(dev) : cfd;
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ptmg->sfd = sfd == -1 ? minor(dev) : sfd;
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error = (*ptm->makename)(ptm, l, ptmg->cn, sizeof(ptmg->cn), dev, 'p');
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if (error)
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return error;
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return (*ptm->makename)(ptm, l, ptmg->sn, sizeof(ptmg->sn), dev, 't');
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}
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void
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/*ARGSUSED*/
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ptmattach(int n)
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{
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extern const struct cdevsw pts_cdevsw, ptc_cdevsw;
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/* find the major and minor of the pty devices */
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if ((pts_major = cdevsw_lookup_major(&pts_cdevsw)) == -1)
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panic("ptmattach: Can't find pty slave in cdevsw");
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if ((ptc_major = cdevsw_lookup_major(&ptc_cdevsw)) == -1)
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panic("ptmattach: Can't find pty master in cdevsw");
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#ifdef COMPAT_BSDPTY
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ptm = &ptm_bsdpty;
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#endif
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}
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static int
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/*ARGSUSED*/
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ptmopen(dev_t dev, int flag, int mode, struct lwp *l)
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{
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int error;
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int fd;
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dev_t ttydev;
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switch(minor(dev)) {
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case 0: /* /dev/ptmx */
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case 2: /* /emul/linux/dev/ptmx */
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if ((error = pty_alloc_master(l, &fd, &ttydev)) != 0)
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return error;
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if (minor(dev) == 2) {
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/*
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* Linux ptyfs grants the pty right here.
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* Handle this case here, instead of writing
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* a new linux module.
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*/
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if ((error = pty_grant_slave(l, ttydev)) != 0) {
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file_t *fp = fd_getfile(fd);
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if (fp != NULL) {
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fd_close(fd);
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}
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return error;
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}
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}
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curlwp->l_dupfd = fd;
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return EMOVEFD;
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case 1: /* /dev/ptm */
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return 0;
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default:
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return ENODEV;
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}
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}
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static int
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/*ARGSUSED*/
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ptmclose(dev_t dev, int flag, int mode, struct lwp *l)
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{
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return (0);
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}
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static int
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/*ARGSUSED*/
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ptmioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
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{
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int error;
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dev_t newdev;
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int cfd, sfd;
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file_t *fp;
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error = 0;
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switch (cmd) {
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case TIOCPTMGET:
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if ((error = pty_alloc_master(l, &cfd, &newdev)) != 0)
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return error;
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if ((error = pty_grant_slave(l, newdev)) != 0)
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goto bad;
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if ((error = pty_alloc_slave(l, &sfd, newdev)) != 0)
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goto bad;
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/* now, put the indices and names into struct ptmget */
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return pty_fill_ptmget(l, newdev, cfd, sfd, data);
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default:
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DPRINTF(("ptmioctl EINVAL\n"));
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return EINVAL;
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}
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bad:
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fp = fd_getfile(cfd);
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if (fp != NULL) {
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fd_close(cfd);
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}
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return error;
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}
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const struct cdevsw ptm_cdevsw = {
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ptmopen, ptmclose, noread, nowrite, ptmioctl,
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nullstop, notty, nopoll, nommap, nokqfilter, D_TTY
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};
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#endif
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