NetBSD/sys/kern/tty_ptm.c

393 lines
8.8 KiB
C

/* $NetBSD: tty_ptm.c,v 1.9 2006/05/14 21:15:11 elad Exp $ */
/*-
* Copyright (c) 2004 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: tty_ptm.c,v 1.9 2006/05/14 21:15:11 elad Exp $");
#include "opt_ptm.h"
/* pty multiplexor driver /dev/ptm{,x} */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/proc.h>
#include <sys/tty.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/signalvar.h>
#include <sys/uio.h>
#include <sys/filedesc.h>
#include <sys/conf.h>
#include <sys/poll.h>
#include <sys/malloc.h>
#include <sys/pty.h>
#include <sys/kauth.h>
#ifdef DEBUG_PTM
#define DPRINTF(a) printf a
#else
#define DPRINTF(a)
#endif
#ifdef NO_DEV_PTM
const struct cdevsw ptm_cdevsw = {
noopen, noclose, noread, nowrite, noioctl,
nostop, notty, nopoll, nommap, nokqfilter, D_TTY
};
#else
static struct ptm_pty *ptm;
int pts_major, ptc_major;
static dev_t pty_getfree(void);
static int pty_alloc_master(struct lwp *, int *, dev_t *);
static int pty_alloc_slave(struct lwp *, int *, dev_t);
void ptmattach(int);
dev_t
pty_makedev(char ms, int minor)
{
return makedev(ms == 't' ? pts_major : ptc_major, minor);
}
static dev_t
pty_getfree(void)
{
extern struct simplelock pt_softc_mutex;
int i;
simple_lock(&pt_softc_mutex);
for (i = 0; i < npty; i++) {
if (pty_isfree(i, 0))
break;
}
simple_unlock(&pt_softc_mutex);
return pty_makedev('t', i);
}
/*
* Hacked up version of vn_open. We _only_ handle ptys and only open
* them with FREAD|FWRITE and never deal with creat or stuff like that.
*
* We need it because we have to fake up root credentials to open the pty.
*/
int
pty_vn_open(struct vnode *vp, struct lwp *l)
{
kauth_cred_t cred;
int error;
if (vp->v_type != VCHR) {
vput(vp);
return EINVAL;
}
/*
* Get us a fresh cred with root privileges.
*/
cred = kauth_cred_alloc();
error = VOP_OPEN(vp, FREAD|FWRITE, cred, l);
kauth_cred_free(cred);
if (error) {
vput(vp);
return error;
}
vp->v_writecount++;
return 0;
}
static int
pty_alloc_master(struct lwp *l, int *fd, dev_t *dev)
{
int error;
struct file *fp;
struct vnode *vp;
struct proc *p = l->l_proc;
int md;
if ((error = falloc(p, &fp, fd)) != 0) {
DPRINTF(("falloc %d\n", error));
return error;
}
retry:
/* Find and open a free master pty. */
*dev = pty_getfree();
md = minor(*dev);
if ((error = pty_check(md)) != 0) {
DPRINTF(("pty_check %d\n", error));
goto bad;
}
if (ptm == NULL) {
error = EOPNOTSUPP;
goto bad;
}
if ((error = (*ptm->allocvp)(ptm, l, &vp, *dev, 'p')) != 0)
goto bad;
if ((error = pty_vn_open(vp, l)) != 0) {
/*
* Check if the master open failed because we lost
* the race to grab it.
*/
if (error != EIO)
goto bad;
error = !pty_isfree(md, 1);
if (error)
goto retry;
else
goto bad;
}
fp->f_flag = FREAD|FWRITE;
fp->f_type = DTYPE_VNODE;
fp->f_ops = &vnops;
fp->f_data = vp;
VOP_UNLOCK(vp, 0);
FILE_SET_MATURE(fp);
FILE_UNUSE(fp, l);
return 0;
bad:
FILE_UNUSE(fp, l);
fdremove(p->p_fd, *fd);
ffree(fp);
return error;
}
int
pty_grant_slave(struct lwp *l, dev_t dev)
{
int error;
struct vnode *vp;
/*
* Open the slave.
* namei -> setattr -> unlock -> revoke -> vrele ->
* namei -> open -> unlock
* Three stage rocket:
* 1. Change the owner and permissions on the slave.
* 2. Revoke all the users of the slave.
* 3. open the slave.
*/
if (ptm == NULL)
return EOPNOTSUPP;
if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0)
return error;
if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
struct vattr vattr;
kauth_cred_t cred;
(*ptm->getvattr)(ptm, l->l_proc, &vattr);
/* Get a fake cred to pretend we're root. */
cred = kauth_cred_alloc();
error = VOP_SETATTR(vp, &vattr, cred, l);
kauth_cred_free(cred);
if (error) {
DPRINTF(("setattr %d\n", error));
VOP_UNLOCK(vp, 0);
vrele(vp);
return error;
}
}
VOP_UNLOCK(vp, 0);
if (vp->v_usecount > 1 ||
(vp->v_flag & (VALIASED | VLAYER)))
VOP_REVOKE(vp, REVOKEALL);
/*
* The vnode is useless after the revoke, we need to get it again.
*/
vrele(vp);
return 0;
}
static int
pty_alloc_slave(struct lwp *l, int *fd, dev_t dev)
{
int error;
struct file *fp;
struct vnode *vp;
struct proc *p = l->l_proc;
/* Grab a filedescriptor for the slave */
if ((error = falloc(p, &fp, fd)) != 0) {
DPRINTF(("falloc %d\n", error));
return error;
}
if (ptm == NULL) {
error = EOPNOTSUPP;
goto bad;
}
if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0)
goto bad;
if ((error = pty_vn_open(vp, l)) != 0)
goto bad;
fp->f_flag = FREAD|FWRITE;
fp->f_type = DTYPE_VNODE;
fp->f_ops = &vnops;
fp->f_data = vp;
VOP_UNLOCK(vp, 0);
FILE_SET_MATURE(fp);
FILE_UNUSE(fp, l);
return 0;
bad:
FILE_UNUSE(fp, l);
fdremove(p->p_fd, *fd);
ffree(fp);
return error;
}
struct ptm_pty *
pty_sethandler(struct ptm_pty *nptm)
{
struct ptm_pty *optm = ptm;
ptm = nptm;
return optm;
}
int
pty_fill_ptmget(struct lwp *l, dev_t dev, int cfd, int sfd, void *data)
{
struct ptmget *ptmg = data;
int error;
if (ptm == NULL)
return EOPNOTSUPP;
ptmg->cfd = cfd == -1 ? minor(dev) : cfd;
ptmg->sfd = sfd == -1 ? minor(dev) : sfd;
error = (*ptm->makename)(ptm, l, ptmg->cn, sizeof(ptmg->cn), dev, 'p');
if (error)
return error;
return (*ptm->makename)(ptm, l, ptmg->sn, sizeof(ptmg->sn), dev, 't');
}
void
/*ARGSUSED*/
ptmattach(int n)
{
extern const struct cdevsw pts_cdevsw, ptc_cdevsw;
/* find the major and minor of the pty devices */
if ((pts_major = cdevsw_lookup_major(&pts_cdevsw)) == -1)
panic("ptmattach: Can't find pty slave in cdevsw");
if ((ptc_major = cdevsw_lookup_major(&ptc_cdevsw)) == -1)
panic("ptmattach: Can't find pty master in cdevsw");
#ifdef COMPAT_BSDPTY
ptm = &ptm_bsdpty;
#endif
}
static int
/*ARGSUSED*/
ptmopen(dev_t dev, int flag, int mode, struct lwp *l)
{
int error;
int fd;
switch(minor(dev)) {
case 0: /* /dev/ptmx */
if ((error = pty_alloc_master(l, &fd, &dev)) != 0)
return error;
curlwp->l_dupfd = fd;
return EMOVEFD;
case 1: /* /dev/ptm */
return 0;
default:
return ENODEV;
}
}
static int
/*ARGSUSED*/
ptmclose(dev_t dev, int flag, int mode, struct lwp *l)
{
return (0);
}
static int
/*ARGSUSED*/
ptmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct lwp *l)
{
int error;
dev_t newdev;
int cfd, sfd;
struct file *fp;
struct proc *p = l->l_proc;
error = 0;
switch (cmd) {
case TIOCPTMGET:
if ((error = pty_alloc_master(l, &cfd, &newdev)) != 0)
return error;
if ((error = pty_grant_slave(l, newdev)) != 0)
goto bad;
if ((error = pty_alloc_slave(l, &sfd, newdev)) != 0)
goto bad;
/* now, put the indices and names into struct ptmget */
return pty_fill_ptmget(l, newdev, cfd, sfd, data);
default:
DPRINTF(("ptmioctl EINVAL\n"));
return EINVAL;
}
bad:
fp = fd_getfile(p->p_fd, cfd);
fdremove(p->p_fd, cfd);
ffree(fp);
return error;
}
const struct cdevsw ptm_cdevsw = {
ptmopen, ptmclose, noread, nowrite, ptmioctl,
nullstop, notty, nopoll, nommap, nokqfilter, D_TTY
};
#endif