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tty_ptm.c revision 1.27
      1  1.27   hannken /*	$NetBSD: tty_ptm.c,v 1.27 2010/06/24 13:03:11 hannken Exp $	*/
      2   1.1  christos 
      3   1.1  christos /*-
      4   1.1  christos  * Copyright (c) 2004 The NetBSD Foundation, Inc.
      5   1.1  christos  * All rights reserved.
      6   1.1  christos  *
      7   1.1  christos  * Redistribution and use in source and binary forms, with or without
      8   1.1  christos  * modification, are permitted provided that the following conditions
      9   1.1  christos  * are met:
     10   1.1  christos  * 1. Redistributions of source code must retain the above copyright
     11   1.1  christos  *    notice, this list of conditions and the following disclaimer.
     12   1.1  christos  * 2. Redistributions in binary form must reproduce the above copyright
     13   1.1  christos  *    notice, this list of conditions and the following disclaimer in the
     14   1.1  christos  *    documentation and/or other materials provided with the distribution.
     15   1.1  christos  *
     16   1.1  christos  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17   1.1  christos  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18   1.1  christos  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19   1.1  christos  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20   1.1  christos  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21   1.1  christos  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22   1.1  christos  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23   1.1  christos  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24   1.1  christos  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25   1.1  christos  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26   1.1  christos  * POSSIBILITY OF SUCH DAMAGE.
     27   1.1  christos  */
     28   1.1  christos 
     29   1.1  christos #include <sys/cdefs.h>
     30  1.27   hannken __KERNEL_RCSID(0, "$NetBSD: tty_ptm.c,v 1.27 2010/06/24 13:03:11 hannken Exp $");
     31   1.1  christos 
     32   1.1  christos #include "opt_ptm.h"
     33   1.1  christos 
     34   1.1  christos /* pty multiplexor driver /dev/ptm{,x} */
     35   1.1  christos 
     36   1.1  christos #include <sys/param.h>
     37   1.1  christos #include <sys/systm.h>
     38   1.1  christos #include <sys/ioctl.h>
     39   1.1  christos #include <sys/proc.h>
     40   1.1  christos #include <sys/tty.h>
     41   1.1  christos #include <sys/stat.h>
     42   1.1  christos #include <sys/file.h>
     43   1.1  christos #include <sys/uio.h>
     44   1.1  christos #include <sys/kernel.h>
     45   1.1  christos #include <sys/vnode.h>
     46   1.1  christos #include <sys/namei.h>
     47   1.1  christos #include <sys/signalvar.h>
     48   1.1  christos #include <sys/filedesc.h>
     49   1.1  christos #include <sys/conf.h>
     50   1.1  christos #include <sys/poll.h>
     51   1.1  christos #include <sys/pty.h>
     52   1.9      elad #include <sys/kauth.h>
     53   1.1  christos 
     54  1.23        ad #include <miscfs/specfs/specdev.h>
     55  1.23        ad 
     56   1.1  christos #ifdef DEBUG_PTM
     57   1.1  christos #define DPRINTF(a)	printf a
     58   1.1  christos #else
     59   1.1  christos #define DPRINTF(a)
     60   1.1  christos #endif
     61   1.1  christos 
     62   1.1  christos #ifdef NO_DEV_PTM
     63   1.1  christos const struct cdevsw ptm_cdevsw = {
     64   1.1  christos 	noopen, noclose, noread, nowrite, noioctl,
     65   1.1  christos 	nostop, notty, nopoll, nommap, nokqfilter, D_TTY
     66   1.1  christos };
     67   1.1  christos #else
     68   1.1  christos 
     69   1.1  christos static struct ptm_pty *ptm;
     70   1.1  christos int pts_major, ptc_major;
     71   1.1  christos 
     72   1.1  christos static dev_t pty_getfree(void);
     73   1.7  christos static int pty_alloc_master(struct lwp *, int *, dev_t *);
     74   1.7  christos static int pty_alloc_slave(struct lwp *, int *, dev_t);
     75   1.1  christos 
     76   1.1  christos void ptmattach(int);
     77   1.1  christos 
     78   1.1  christos dev_t
     79   1.1  christos pty_makedev(char ms, int minor)
     80   1.1  christos {
     81   1.1  christos 	return makedev(ms == 't' ? pts_major : ptc_major, minor);
     82   1.1  christos }
     83   1.1  christos 
     84   1.5   thorpej 
     85   1.1  christos static dev_t
     86   1.1  christos pty_getfree(void)
     87   1.1  christos {
     88  1.18        ad 	extern kmutex_t pt_softc_mutex;
     89   1.1  christos 	int i;
     90   1.1  christos 
     91  1.18        ad 	mutex_enter(&pt_softc_mutex);
     92   1.1  christos 	for (i = 0; i < npty; i++) {
     93   1.1  christos 		if (pty_isfree(i, 0))
     94   1.1  christos 			break;
     95   1.1  christos 	}
     96  1.18        ad 	mutex_exit(&pt_softc_mutex);
     97   1.1  christos 	return pty_makedev('t', i);
     98   1.1  christos }
     99   1.1  christos 
    100   1.1  christos /*
    101   1.1  christos  * Hacked up version of vn_open. We _only_ handle ptys and only open
    102   1.1  christos  * them with FREAD|FWRITE and never deal with creat or stuff like that.
    103   1.1  christos  *
    104   1.1  christos  * We need it because we have to fake up root credentials to open the pty.
    105   1.1  christos  */
    106   1.1  christos int
    107   1.7  christos pty_vn_open(struct vnode *vp, struct lwp *l)
    108   1.1  christos {
    109   1.1  christos 	int error;
    110   1.1  christos 
    111   1.1  christos 	if (vp->v_type != VCHR) {
    112   1.1  christos 		vput(vp);
    113   1.1  christos 		return EINVAL;
    114   1.1  christos 	}
    115   1.1  christos 
    116  1.21     pooka 	error = VOP_OPEN(vp, FREAD|FWRITE, lwp0.l_cred);
    117   1.1  christos 
    118   1.1  christos 	if (error) {
    119   1.1  christos 		vput(vp);
    120   1.1  christos 		return error;
    121   1.1  christos 	}
    122   1.1  christos 
    123   1.1  christos 	vp->v_writecount++;
    124   1.1  christos 
    125   1.1  christos 	return 0;
    126   1.1  christos }
    127   1.1  christos 
    128   1.1  christos static int
    129   1.7  christos pty_alloc_master(struct lwp *l, int *fd, dev_t *dev)
    130   1.1  christos {
    131   1.1  christos 	int error;
    132   1.1  christos 	struct file *fp;
    133   1.1  christos 	struct vnode *vp;
    134   1.1  christos 	int md;
    135   1.1  christos 
    136  1.24        ad 	if ((error = fd_allocfile(&fp, fd)) != 0) {
    137  1.24        ad 		DPRINTF(("fd_allocfile %d\n", error));
    138   1.1  christos 		return error;
    139   1.1  christos 	}
    140   1.1  christos retry:
    141   1.1  christos 	/* Find and open a free master pty. */
    142   1.1  christos 	*dev = pty_getfree();
    143   1.1  christos 	md = minor(*dev);
    144   1.1  christos 	if ((error = pty_check(md)) != 0) {
    145   1.1  christos 		DPRINTF(("pty_check %d\n", error));
    146   1.1  christos 		goto bad;
    147   1.1  christos 	}
    148   1.1  christos 	if (ptm == NULL) {
    149  1.13  christos 		DPRINTF(("no ptm\n"));
    150   1.1  christos 		error = EOPNOTSUPP;
    151   1.1  christos 		goto bad;
    152   1.1  christos 	}
    153  1.13  christos 	if ((error = (*ptm->allocvp)(ptm, l, &vp, *dev, 'p')) != 0) {
    154  1.13  christos 		DPRINTF(("pty_allocvp %d\n", error));
    155   1.1  christos 		goto bad;
    156  1.13  christos 	}
    157   1.1  christos 
    158   1.7  christos 	if ((error = pty_vn_open(vp, l)) != 0) {
    159  1.13  christos 		DPRINTF(("pty_vn_open %d\n", error));
    160   1.1  christos 		/*
    161   1.1  christos 		 * Check if the master open failed because we lost
    162   1.1  christos 		 * the race to grab it.
    163   1.1  christos 		 */
    164   1.1  christos 		if (error != EIO)
    165   1.1  christos 			goto bad;
    166   1.1  christos 		error = !pty_isfree(md, 1);
    167  1.13  christos 		DPRINTF(("pty_isfree %d\n", error));
    168   1.1  christos 		if (error)
    169   1.1  christos 			goto retry;
    170   1.1  christos 		else
    171   1.1  christos 			goto bad;
    172   1.1  christos 	}
    173   1.1  christos 	fp->f_flag = FREAD|FWRITE;
    174   1.1  christos 	fp->f_type = DTYPE_VNODE;
    175   1.1  christos 	fp->f_ops = &vnops;
    176   1.1  christos 	fp->f_data = vp;
    177  1.27   hannken 	VOP_UNLOCK(vp);
    178  1.24        ad 	fd_affix(curproc, fp, *fd);
    179   1.1  christos 	return 0;
    180   1.1  christos bad:
    181  1.24        ad 	fd_abort(curproc, fp, *fd);
    182   1.1  christos 	return error;
    183   1.1  christos }
    184   1.1  christos 
    185   1.1  christos int
    186   1.7  christos pty_grant_slave(struct lwp *l, dev_t dev)
    187   1.1  christos {
    188   1.1  christos 	int error;
    189   1.1  christos 	struct vnode *vp;
    190   1.1  christos 
    191   1.1  christos 	/*
    192   1.1  christos 	 * Open the slave.
    193   1.1  christos 	 * namei -> setattr -> unlock -> revoke -> vrele ->
    194   1.1  christos 	 * namei -> open -> unlock
    195   1.1  christos 	 * Three stage rocket:
    196   1.1  christos 	 * 1. Change the owner and permissions on the slave.
    197   1.1  christos 	 * 2. Revoke all the users of the slave.
    198   1.1  christos 	 * 3. open the slave.
    199   1.1  christos 	 */
    200   1.1  christos 	if (ptm == NULL)
    201   1.1  christos 		return EOPNOTSUPP;
    202   1.7  christos 	if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0)
    203   1.1  christos 		return error;
    204   1.1  christos 
    205   1.1  christos 	if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
    206   1.1  christos 		struct vattr vattr;
    207  1.11        ad 		(*ptm->getvattr)(ptm, l, &vattr);
    208  1.10        ad 		/* Do the VOP_SETATTR() as root. */
    209  1.21     pooka 		error = VOP_SETATTR(vp, &vattr, lwp0.l_cred);
    210   1.1  christos 		if (error) {
    211   1.1  christos 			DPRINTF(("setattr %d\n", error));
    212  1.27   hannken 			VOP_UNLOCK(vp);
    213   1.1  christos 			vrele(vp);
    214   1.1  christos 			return error;
    215   1.1  christos 		}
    216   1.1  christos 	}
    217  1.27   hannken 	VOP_UNLOCK(vp);
    218  1.23        ad 	VOP_REVOKE(vp, REVOKEALL);
    219   1.1  christos 
    220   1.1  christos 	/*
    221   1.1  christos 	 * The vnode is useless after the revoke, we need to get it again.
    222   1.1  christos 	 */
    223   1.1  christos 	vrele(vp);
    224   1.1  christos 	return 0;
    225   1.1  christos }
    226   1.1  christos 
    227   1.1  christos static int
    228   1.7  christos pty_alloc_slave(struct lwp *l, int *fd, dev_t dev)
    229   1.1  christos {
    230   1.1  christos 	int error;
    231   1.1  christos 	struct file *fp;
    232   1.1  christos 	struct vnode *vp;
    233   1.1  christos 
    234   1.1  christos 	/* Grab a filedescriptor for the slave */
    235  1.24        ad 	if ((error = fd_allocfile(&fp, fd)) != 0) {
    236  1.24        ad 		DPRINTF(("fd_allocfile %d\n", error));
    237   1.1  christos 		return error;
    238   1.1  christos 	}
    239   1.1  christos 
    240   1.1  christos 	if (ptm == NULL) {
    241   1.1  christos 		error = EOPNOTSUPP;
    242   1.1  christos 		goto bad;
    243   1.1  christos 	}
    244   1.1  christos 
    245   1.7  christos 	if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0)
    246   1.1  christos 		goto bad;
    247   1.7  christos 	if ((error = pty_vn_open(vp, l)) != 0)
    248   1.1  christos 		goto bad;
    249   1.1  christos 
    250   1.1  christos 	fp->f_flag = FREAD|FWRITE;
    251   1.1  christos 	fp->f_type = DTYPE_VNODE;
    252   1.1  christos 	fp->f_ops = &vnops;
    253   1.1  christos 	fp->f_data = vp;
    254  1.27   hannken 	VOP_UNLOCK(vp);
    255  1.24        ad 	fd_affix(curproc, fp, *fd);
    256   1.1  christos 	return 0;
    257   1.1  christos bad:
    258  1.24        ad 	fd_abort(curproc, fp, *fd);
    259   1.1  christos 	return error;
    260   1.1  christos }
    261   1.1  christos 
    262   1.1  christos struct ptm_pty *
    263   1.1  christos pty_sethandler(struct ptm_pty *nptm)
    264   1.1  christos {
    265   1.1  christos 	struct ptm_pty *optm = ptm;
    266   1.1  christos 	ptm = nptm;
    267   1.1  christos 	return optm;
    268   1.1  christos }
    269   1.1  christos 
    270   1.1  christos int
    271   1.8  christos pty_fill_ptmget(struct lwp *l, dev_t dev, int cfd, int sfd, void *data)
    272   1.1  christos {
    273   1.1  christos 	struct ptmget *ptmg = data;
    274   1.1  christos 	int error;
    275   1.1  christos 
    276   1.1  christos 	if (ptm == NULL)
    277   1.1  christos 		return EOPNOTSUPP;
    278   1.1  christos 
    279   1.2  christos 	ptmg->cfd = cfd == -1 ? minor(dev) : cfd;
    280   1.2  christos 	ptmg->sfd = sfd == -1 ? minor(dev) : sfd;
    281   1.1  christos 
    282   1.8  christos 	error = (*ptm->makename)(ptm, l, ptmg->cn, sizeof(ptmg->cn), dev, 'p');
    283   1.1  christos 	if (error)
    284   1.1  christos 		return error;
    285   1.1  christos 
    286   1.8  christos 	return (*ptm->makename)(ptm, l, ptmg->sn, sizeof(ptmg->sn), dev, 't');
    287   1.1  christos }
    288   1.1  christos 
    289   1.1  christos void
    290   1.1  christos /*ARGSUSED*/
    291  1.15      yamt ptmattach(int n)
    292   1.1  christos {
    293   1.1  christos 	extern const struct cdevsw pts_cdevsw, ptc_cdevsw;
    294   1.1  christos 	/* find the major and minor of the pty devices */
    295   1.1  christos 	if ((pts_major = cdevsw_lookup_major(&pts_cdevsw)) == -1)
    296   1.1  christos 		panic("ptmattach: Can't find pty slave in cdevsw");
    297   1.1  christos 	if ((ptc_major = cdevsw_lookup_major(&ptc_cdevsw)) == -1)
    298   1.1  christos 		panic("ptmattach: Can't find pty master in cdevsw");
    299   1.1  christos #ifdef COMPAT_BSDPTY
    300   1.1  christos 	ptm = &ptm_bsdpty;
    301   1.1  christos #endif
    302   1.1  christos }
    303   1.1  christos 
    304   1.5   thorpej static int
    305   1.1  christos /*ARGSUSED*/
    306  1.15      yamt ptmopen(dev_t dev, int flag, int mode, struct lwp *l)
    307   1.1  christos {
    308   1.1  christos 	int error;
    309   1.1  christos 	int fd;
    310  1.13  christos 	dev_t ttydev;
    311   1.1  christos 
    312   1.1  christos 	switch(minor(dev)) {
    313   1.1  christos 	case 0:		/* /dev/ptmx */
    314  1.12  christos 	case 2:		/* /emul/linux/dev/ptmx */
    315  1.13  christos 		if ((error = pty_alloc_master(l, &fd, &ttydev)) != 0)
    316   1.1  christos 			return error;
    317  1.12  christos 		if (minor(dev) == 2) {
    318  1.12  christos 			/*
    319  1.12  christos 			 * Linux ptyfs grants the pty right here.
    320  1.12  christos 			 * Handle this case here, instead of writing
    321  1.12  christos 			 * a new linux module.
    322  1.12  christos 			 */
    323  1.13  christos 			if ((error = pty_grant_slave(l, ttydev)) != 0) {
    324  1.24        ad 				file_t *fp = fd_getfile(fd);
    325  1.16       alc 				if (fp != NULL) {
    326  1.24        ad 					fd_close(fd);
    327  1.16       alc 				}
    328  1.12  christos 				return error;
    329  1.12  christos 			}
    330  1.12  christos 		}
    331   1.1  christos 		curlwp->l_dupfd = fd;
    332   1.4  christos 		return EMOVEFD;
    333   1.1  christos 	case 1:		/* /dev/ptm */
    334   1.1  christos 		return 0;
    335   1.1  christos 	default:
    336   1.1  christos 		return ENODEV;
    337   1.1  christos 	}
    338   1.1  christos }
    339   1.1  christos 
    340   1.5   thorpej static int
    341   1.1  christos /*ARGSUSED*/
    342  1.15      yamt ptmclose(dev_t dev, int flag, int mode, struct lwp *l)
    343   1.1  christos {
    344  1.15      yamt 
    345   1.1  christos 	return (0);
    346   1.1  christos }
    347   1.1  christos 
    348   1.5   thorpej static int
    349   1.1  christos /*ARGSUSED*/
    350  1.17  christos ptmioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
    351   1.1  christos {
    352   1.1  christos 	int error;
    353   1.1  christos 	dev_t newdev;
    354   1.1  christos 	int cfd, sfd;
    355  1.24        ad 	file_t *fp;
    356   1.1  christos 
    357   1.1  christos 	error = 0;
    358   1.1  christos 	switch (cmd) {
    359   1.1  christos 	case TIOCPTMGET:
    360   1.7  christos 		if ((error = pty_alloc_master(l, &cfd, &newdev)) != 0)
    361   1.1  christos 			return error;
    362   1.1  christos 
    363   1.7  christos 		if ((error = pty_grant_slave(l, newdev)) != 0)
    364   1.1  christos 			goto bad;
    365   1.1  christos 
    366   1.7  christos 		if ((error = pty_alloc_slave(l, &sfd, newdev)) != 0)
    367   1.1  christos 			goto bad;
    368   1.1  christos 
    369   1.1  christos 		/* now, put the indices and names into struct ptmget */
    370   1.8  christos 		return pty_fill_ptmget(l, newdev, cfd, sfd, data);
    371   1.1  christos 	default:
    372   1.1  christos 		DPRINTF(("ptmioctl EINVAL\n"));
    373   1.1  christos 		return EINVAL;
    374   1.1  christos 	}
    375  1.24        ad  bad:
    376  1.24        ad 	fp = fd_getfile(cfd);
    377  1.16       alc 	if (fp != NULL) {
    378  1.24        ad 		fd_close(cfd);
    379  1.16       alc 	}
    380   1.1  christos 	return error;
    381   1.1  christos }
    382   1.5   thorpej 
    383   1.5   thorpej const struct cdevsw ptm_cdevsw = {
    384   1.5   thorpej 	ptmopen, ptmclose, noread, nowrite, ptmioctl,
    385   1.5   thorpej 	nullstop, notty, nopoll, nommap, nokqfilter, D_TTY
    386   1.5   thorpej };
    387   1.6        he #endif
    388