Home | History | Annotate | Line # | Download | only in ptyfs
ptyfs_vnops.c revision 1.2
      1 /*	$NetBSD: ptyfs_vnops.c,v 1.2 2004/11/11 19:19:59 jdolecek Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1993, 1995
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Jan-Simon Pendry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *	@(#)procfs_vnops.c	8.18 (Berkeley) 5/21/95
     35  */
     36 
     37 /*
     38  * Copyright (c) 1993 Jan-Simon Pendry
     39  *
     40  * This code is derived from software contributed to Berkeley by
     41  * Jan-Simon Pendry.
     42  *
     43  * Redistribution and use in source and binary forms, with or without
     44  * modification, are permitted provided that the following conditions
     45  * are met:
     46  * 1. Redistributions of source code must retain the above copyright
     47  *    notice, this list of conditions and the following disclaimer.
     48  * 2. Redistributions in binary form must reproduce the above copyright
     49  *    notice, this list of conditions and the following disclaimer in the
     50  *    documentation and/or other materials provided with the distribution.
     51  * 3. All advertising materials mentioning features or use of this software
     52  *    must display the following acknowledgement:
     53  *	This product includes software developed by the University of
     54  *	California, Berkeley and its contributors.
     55  * 4. Neither the name of the University nor the names of its contributors
     56  *    may be used to endorse or promote products derived from this software
     57  *    without specific prior written permission.
     58  *
     59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     69  * SUCH DAMAGE.
     70  *
     71  *	@(#)procfs_vnops.c	8.18 (Berkeley) 5/21/95
     72  */
     73 
     74 /*
     75  * ptyfs vnode interface
     76  */
     77 
     78 #include <sys/cdefs.h>
     79 __KERNEL_RCSID(0, "$NetBSD: ptyfs_vnops.c,v 1.2 2004/11/11 19:19:59 jdolecek Exp $");
     80 
     81 #include <sys/param.h>
     82 #include <sys/systm.h>
     83 #include <sys/time.h>
     84 #include <sys/kernel.h>
     85 #include <sys/file.h>
     86 #include <sys/filedesc.h>
     87 #include <sys/proc.h>
     88 #include <sys/vnode.h>
     89 #include <sys/namei.h>
     90 #include <sys/malloc.h>
     91 #include <sys/mount.h>
     92 #include <sys/select.h>
     93 #include <sys/dirent.h>
     94 #include <sys/resourcevar.h>
     95 #include <sys/stat.h>
     96 #include <sys/conf.h>
     97 #include <sys/tty.h>
     98 #include <sys/pty.h>
     99 
    100 #include <uvm/uvm_extern.h>	/* for PAGE_SIZE */
    101 
    102 #include <machine/reg.h>
    103 
    104 #include <fs/ptyfs/ptyfs.h>
    105 #include <miscfs/genfs/genfs.h>
    106 #include <miscfs/specfs/specdev.h>
    107 
    108 /*
    109  * Vnode Operations.
    110  *
    111  */
    112 
    113 int	ptyfs_lookup	(void *);
    114 #define	ptyfs_create	genfs_eopnotsupp
    115 #define	ptyfs_mknod	genfs_eopnotsupp
    116 int	ptyfs_open	(void *);
    117 int	ptyfs_close	(void *);
    118 int	ptyfs_access	(void *);
    119 int	ptyfs_getattr	(void *);
    120 int	ptyfs_setattr	(void *);
    121 int	ptyfs_read	(void *);
    122 int	ptyfs_write	(void *);
    123 #define	ptyfs_fcntl	genfs_fcntl
    124 int	ptyfs_ioctl	(void *);
    125 int	ptyfs_poll	(void *);
    126 int	ptyfs_kqfilter	(void *);
    127 #define ptyfs_revoke	genfs_revoke
    128 #define	ptyfs_mmap	genfs_eopnotsupp
    129 #define	ptyfs_fsync	genfs_nullop
    130 #define	ptyfs_seek	genfs_nullop
    131 #define	ptyfs_remove	genfs_eopnotsupp
    132 #define	ptyfs_link	genfs_abortop
    133 #define	ptyfs_rename	genfs_eopnotsupp
    134 #define	ptyfs_mkdir	genfs_eopnotsupp
    135 #define	ptyfs_rmdir	genfs_eopnotsupp
    136 #define	ptyfs_symlink	genfs_abortop
    137 int	ptyfs_readdir	(void *);
    138 #define	ptyfs_readlink	genfs_eopnotsupp
    139 #define	ptyfs_abortop	genfs_abortop
    140 int	ptyfs_inactive	(void *);
    141 int	ptyfs_reclaim	(void *);
    142 #define	ptyfs_lock	genfs_lock
    143 #define	ptyfs_unlock	genfs_unlock
    144 #define	ptyfs_bmap	genfs_badop
    145 #define	ptyfs_strategy	genfs_badop
    146 int	ptyfs_print	(void *);
    147 int	ptyfs_pathconf	(void *);
    148 #define	ptyfs_islocked	genfs_islocked
    149 #define	ptyfs_advlock	genfs_einval
    150 #define	ptyfs_blkatoff	genfs_eopnotsupp
    151 #define	ptyfs_valloc	genfs_eopnotsupp
    152 #define	ptyfs_vfree	genfs_nullop
    153 #define	ptyfs_truncate	genfs_eopnotsupp
    154 int	ptyfs_update	(void *);
    155 #define	ptyfs_bwrite	genfs_eopnotsupp
    156 #define ptyfs_putpages	genfs_null_putpages
    157 
    158 static int ptyfs_chown(struct vnode *, uid_t, gid_t, struct ucred *,
    159     struct proc *);
    160 static int ptyfs_chmod(struct vnode *, mode_t, struct ucred *, struct proc *);
    161 static void ptyfs_time(struct ptyfsnode *, struct timespec *,
    162     struct timespec *);
    163 static int atoi(const char *, size_t);
    164 static u_int digits(u_int);
    165 
    166 extern const struct cdevsw pts_cdevsw, ptc_cdevsw;
    167 
    168 /*
    169  * ptyfs vnode operations.
    170  */
    171 int (**ptyfs_vnodeop_p)(void *);
    172 const struct vnodeopv_entry_desc ptyfs_vnodeop_entries[] = {
    173 	{ &vop_default_desc, vn_default_error },
    174 	{ &vop_lookup_desc, ptyfs_lookup },		/* lookup */
    175 	{ &vop_create_desc, ptyfs_create },		/* create */
    176 	{ &vop_mknod_desc, ptyfs_mknod },		/* mknod */
    177 	{ &vop_open_desc, ptyfs_open },			/* open */
    178 	{ &vop_close_desc, ptyfs_close },		/* close */
    179 	{ &vop_access_desc, ptyfs_access },		/* access */
    180 	{ &vop_getattr_desc, ptyfs_getattr },		/* getattr */
    181 	{ &vop_setattr_desc, ptyfs_setattr },		/* setattr */
    182 	{ &vop_read_desc, ptyfs_read },			/* read */
    183 	{ &vop_write_desc, ptyfs_write },		/* write */
    184 	{ &vop_ioctl_desc, ptyfs_ioctl },		/* ioctl */
    185 	{ &vop_fcntl_desc, ptyfs_fcntl },		/* fcntl */
    186 	{ &vop_poll_desc, ptyfs_poll },			/* poll */
    187 	{ &vop_kqfilter_desc, ptyfs_kqfilter },		/* kqfilter */
    188 	{ &vop_revoke_desc, ptyfs_revoke },		/* revoke */
    189 	{ &vop_mmap_desc, ptyfs_mmap },			/* mmap */
    190 	{ &vop_fsync_desc, ptyfs_fsync },		/* fsync */
    191 	{ &vop_seek_desc, ptyfs_seek },			/* seek */
    192 	{ &vop_remove_desc, ptyfs_remove },		/* remove */
    193 	{ &vop_link_desc, ptyfs_link },			/* link */
    194 	{ &vop_rename_desc, ptyfs_rename },		/* rename */
    195 	{ &vop_mkdir_desc, ptyfs_mkdir },		/* mkdir */
    196 	{ &vop_rmdir_desc, ptyfs_rmdir },		/* rmdir */
    197 	{ &vop_symlink_desc, ptyfs_symlink },		/* symlink */
    198 	{ &vop_readdir_desc, ptyfs_readdir },		/* readdir */
    199 	{ &vop_readlink_desc, ptyfs_readlink },		/* readlink */
    200 	{ &vop_abortop_desc, ptyfs_abortop },		/* abortop */
    201 	{ &vop_inactive_desc, ptyfs_inactive },		/* inactive */
    202 	{ &vop_reclaim_desc, ptyfs_reclaim },		/* reclaim */
    203 	{ &vop_lock_desc, ptyfs_lock },			/* lock */
    204 	{ &vop_unlock_desc, ptyfs_unlock },		/* unlock */
    205 	{ &vop_bmap_desc, ptyfs_bmap },			/* bmap */
    206 	{ &vop_strategy_desc, ptyfs_strategy },		/* strategy */
    207 	{ &vop_print_desc, ptyfs_print },		/* print */
    208 	{ &vop_islocked_desc, ptyfs_islocked },		/* islocked */
    209 	{ &vop_pathconf_desc, ptyfs_pathconf },		/* pathconf */
    210 	{ &vop_advlock_desc, ptyfs_advlock },		/* advlock */
    211 	{ &vop_blkatoff_desc, ptyfs_blkatoff },		/* blkatoff */
    212 	{ &vop_valloc_desc, ptyfs_valloc },		/* valloc */
    213 	{ &vop_vfree_desc, ptyfs_vfree },		/* vfree */
    214 	{ &vop_truncate_desc, ptyfs_truncate },		/* truncate */
    215 	{ &vop_update_desc, ptyfs_update },		/* update */
    216 	{ &vop_bwrite_desc, ptyfs_bwrite },		/* bwrite */
    217 	{ &vop_putpages_desc, ptyfs_putpages },		/* putpages */
    218 	{ NULL, NULL }
    219 };
    220 const struct vnodeopv_desc ptyfs_vnodeop_opv_desc =
    221 	{ &ptyfs_vnodeop_p, ptyfs_vnodeop_entries };
    222 
    223 /*
    224  * _inactive is called when the ptyfsnode
    225  * is vrele'd and the reference count goes
    226  * to zero.  (vp) will be on the vnode free
    227  * list, so to get it back vget() must be
    228  * used.
    229  *
    230  * for ptyfs, check if the pty is still
    231  * in use and if it isn't then just throw away
    232  * the vnode by calling vgone().
    233  *
    234  * (vp) is locked on entry, but must be unlocked on exit.
    235  */
    236 int
    237 ptyfs_inactive(void *v)
    238 {
    239 	struct vop_inactive_args /* {
    240 		struct vnode *a_vp;
    241 		struct proc *a_p;
    242 	} */ *ap = v;
    243 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
    244 
    245 	VOP_UNLOCK(ap->a_vp, 0);
    246 	if (pty_isfree(ptyfs->ptyfs_pty, 1))
    247 		vgone(ap->a_vp);
    248 
    249 	return 0;
    250 }
    251 
    252 /*
    253  * _reclaim is called when getnewvnode()
    254  * wants to make use of an entry on the vnode
    255  * free list.  at this time the filesystem needs
    256  * to free any private data and remove the node
    257  * from any private lists.
    258  */
    259 int
    260 ptyfs_reclaim(void *v)
    261 {
    262 	struct vop_reclaim_args /* {
    263 		struct vnode *a_vp;
    264 	} */ *ap = v;
    265 	return ptyfs_freevp(ap->a_vp);
    266 }
    267 
    268 /*
    269  * Return POSIX pathconf information applicable to special devices.
    270  */
    271 int
    272 ptyfs_pathconf(void *v)
    273 {
    274 	struct vop_pathconf_args /* {
    275 		struct vnode *a_vp;
    276 		int a_name;
    277 		register_t *a_retval;
    278 	} */ *ap = v;
    279 
    280 	switch (ap->a_name) {
    281 	case _PC_LINK_MAX:
    282 		*ap->a_retval = LINK_MAX;
    283 		return 0;
    284 	case _PC_MAX_CANON:
    285 		*ap->a_retval = MAX_CANON;
    286 		return 0;
    287 	case _PC_MAX_INPUT:
    288 		*ap->a_retval = MAX_INPUT;
    289 		return 0;
    290 	case _PC_PIPE_BUF:
    291 		*ap->a_retval = PIPE_BUF;
    292 		return 0;
    293 	case _PC_CHOWN_RESTRICTED:
    294 		*ap->a_retval = 1;
    295 		return 0;
    296 	case _PC_VDISABLE:
    297 		*ap->a_retval = _POSIX_VDISABLE;
    298 		return 0;
    299 	case _PC_SYNC_IO:
    300 		*ap->a_retval = 1;
    301 		return 0;
    302 	default:
    303 		return EINVAL;
    304 	}
    305 }
    306 
    307 /*
    308  * _print is used for debugging.
    309  * just print a readable description
    310  * of (vp).
    311  */
    312 int
    313 ptyfs_print(void *v)
    314 {
    315 	struct vop_print_args /* {
    316 		struct vnode *a_vp;
    317 	} */ *ap = v;
    318 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
    319 
    320 	printf("tag VT_PTYFS, type %d, pty %d\n",
    321 	    ptyfs->ptyfs_type, ptyfs->ptyfs_pty);
    322 	return 0;
    323 }
    324 
    325 /*
    326  * Invent attributes for ptyfsnode (vp) and store
    327  * them in (vap).
    328  * Directories lengths are returned as zero since
    329  * any real length would require the genuine size
    330  * to be computed, and nothing cares anyway.
    331  *
    332  * this is relatively minimal for ptyfs.
    333  */
    334 int
    335 ptyfs_getattr(void *v)
    336 {
    337 	struct vop_getattr_args /* {
    338 		struct vnode *a_vp;
    339 		struct vattr *a_vap;
    340 		struct ucred *a_cred;
    341 		struct proc *a_p;
    342 	} */ *ap = v;
    343 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
    344 	struct vattr *vap = ap->a_vap;
    345         struct timespec ts;
    346 
    347 	TIMEVAL_TO_TIMESPEC(&time, &ts);
    348 	ptyfs_time(ptyfs, &ts, &ts);
    349 
    350 	/* start by zeroing out the attributes */
    351 	VATTR_NULL(vap);
    352 
    353 	/* next do all the common fields */
    354 	vap->va_type = ap->a_vp->v_type;
    355 	vap->va_fileid = ptyfs->ptyfs_fileno;
    356 	vap->va_gen = 0;
    357 	vap->va_flags = 0;
    358 	vap->va_nlink = 1;
    359 	vap->va_blocksize = PAGE_SIZE;
    360 
    361 	vap->va_atime = ptyfs->ptyfs_atime;
    362 	vap->va_mtime = ptyfs->ptyfs_mtime;
    363 	vap->va_ctime = ptyfs->ptyfs_ctime;
    364 	vap->va_birthtime = ptyfs->ptyfs_birthtime;
    365 	vap->va_mode = ptyfs->ptyfs_mode;
    366 	vap->va_flags = ptyfs->ptyfs_flags;
    367 	vap->va_uid = ptyfs->ptyfs_uid;
    368 	vap->va_gid = ptyfs->ptyfs_gid;
    369 
    370 	switch (ptyfs->ptyfs_type) {
    371 	case PTYFSpts:
    372 	case PTYFSptc:
    373 		if (pty_isfree(ptyfs->ptyfs_pty, 1))
    374 			return ENOENT;
    375 		vap->va_bytes = vap->va_size = digits(ptyfs->ptyfs_pty);
    376 		vap->va_rdev = ap->a_vp->v_rdev;
    377 		break;
    378 	case PTYFSroot:
    379 		vap->va_rdev = 0;
    380 		vap->va_bytes = vap->va_size = DEV_BSIZE;
    381 		break;
    382 
    383 	default:
    384 		return EOPNOTSUPP;
    385 	}
    386 
    387 	return 0;
    388 }
    389 
    390 /*ARGSUSED*/
    391 int
    392 ptyfs_setattr(void *v)
    393 {
    394 	struct vop_setattr_args /* {
    395 		struct vnodeop_desc *a_desc;
    396 		struct vnode *a_vp;
    397 		struct vattr *a_vap;
    398 		struct ucred *a_cred;
    399 		struct proc *a_p;
    400 	} */ *ap = v;
    401 	struct vnode *vp = ap->a_vp;
    402 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    403 	struct vattr *vap = ap->a_vap;
    404 	struct ucred *cred = ap->a_cred;
    405 	struct proc *p = ap->a_p;
    406 	int error;
    407 
    408 	if (vap->va_size != VNOVAL) {
    409  		switch (ptyfs->ptyfs_type) {
    410  		case PTYFSroot:
    411  			return EISDIR;
    412  		case PTYFSpts:
    413  		case PTYFSptc:
    414 			break;
    415 		default:
    416 			return EINVAL;
    417 		}
    418 	}
    419 
    420 	if (vap->va_flags != VNOVAL) {
    421 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    422 			return EROFS;
    423 		if (cred->cr_uid != ptyfs->ptyfs_uid &&
    424 		    (error = suser(cred, &p->p_acflag)) != 0)
    425 			return error;
    426 		if (cred->cr_uid == 0) {
    427 			if ((ptyfs->ptyfs_flags & (SF_IMMUTABLE | SF_APPEND)) &&
    428 			    securelevel > 0)
    429 				return EPERM;
    430 			/* Snapshot flag cannot be set or cleared */
    431 			if ((vap->va_flags & SF_SNAPSHOT) !=
    432 			    (ptyfs->ptyfs_flags & SF_SNAPSHOT))
    433 				return EPERM;
    434 			ptyfs->ptyfs_flags = vap->va_flags;
    435 		} else {
    436 			if ((ptyfs->ptyfs_flags & (SF_IMMUTABLE | SF_APPEND)) ||
    437 			    (vap->va_flags & UF_SETTABLE) != vap->va_flags)
    438 				return EPERM;
    439 			if ((ptyfs->ptyfs_flags & SF_SETTABLE) !=
    440 			    (vap->va_flags & SF_SETTABLE))
    441 				return EPERM;
    442 			ptyfs->ptyfs_flags &= SF_SETTABLE;
    443 			ptyfs->ptyfs_flags |= (vap->va_flags & UF_SETTABLE);
    444 		}
    445 		ptyfs->ptyfs_flag |= PTYFS_CHANGE;
    446 		if (vap->va_flags & (IMMUTABLE | APPEND))
    447 			return 0;
    448 	}
    449 	if (ptyfs->ptyfs_flags & (IMMUTABLE | APPEND))
    450 		return EPERM;
    451 	/*
    452 	 * Go through the fields and update iff not VNOVAL.
    453 	 */
    454 	if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
    455 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    456 			return EROFS;
    457 		if (ptyfs->ptyfs_type == PTYFSroot)
    458 			return EPERM;
    459 		error = ptyfs_chown(vp, vap->va_uid, vap->va_gid, cred, p);
    460 		if (error)
    461 			return error;
    462 	}
    463 
    464 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL ||
    465 	    vap->va_birthtime.tv_sec != VNOVAL) {
    466 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    467 			return EROFS;
    468 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0)
    469 			return EPERM;
    470 		if (cred->cr_uid != ptyfs->ptyfs_uid &&
    471 		    (error = suser(cred, &p->p_acflag)) &&
    472 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
    473 		    (error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0))
    474 			return (error);
    475 		if (vap->va_atime.tv_sec != VNOVAL)
    476 			if (!(vp->v_mount->mnt_flag & MNT_NOATIME))
    477 				ptyfs->ptyfs_flag |= PTYFS_ACCESS;
    478 		if (vap->va_mtime.tv_sec != VNOVAL)
    479 			ptyfs->ptyfs_flag |= PTYFS_CHANGE | PTYFS_MODIFY;
    480 		if (vap->va_birthtime.tv_sec != VNOVAL)
    481 			ptyfs->ptyfs_birthtime = vap->va_birthtime;
    482 		ptyfs->ptyfs_flag |= PTYFS_CHANGE;
    483 		error = VOP_UPDATE(vp, &vap->va_atime, &vap->va_mtime, 0);
    484 		if (error)
    485 			return error;
    486 	}
    487 	if (vap->va_mode != (mode_t)VNOVAL) {
    488 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    489 			return EROFS;
    490 		if (ptyfs->ptyfs_type == PTYFSroot)
    491 			return EPERM;
    492 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0 &&
    493 		    (vap->va_mode &
    494 		    (S_IXUSR|S_IWUSR|S_IXGRP|S_IWGRP|S_IXOTH|S_IWOTH)))
    495 			return EPERM;
    496 		error = ptyfs_chmod(vp, vap->va_mode, cred, p);
    497 		if (error)
    498 			return error;
    499 	}
    500 	VN_KNOTE(vp, NOTE_ATTRIB);
    501 	return 0;
    502 }
    503 
    504 /*
    505  * Change the mode on a file.
    506  * Inode must be locked before calling.
    507  */
    508 static int
    509 ptyfs_chmod(struct vnode *vp, mode_t mode, struct ucred *cred, struct proc *p)
    510 {
    511 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    512 	int error;
    513 
    514 	if (cred->cr_uid != ptyfs->ptyfs_uid &&
    515 	    (error = suser(cred, &p->p_acflag)) != 0)
    516 		return error;
    517 	ptyfs->ptyfs_mode &= ~ALLPERMS;
    518 	ptyfs->ptyfs_mode |= (mode & ALLPERMS);
    519 	return 0;
    520 }
    521 
    522 /*
    523  * Perform chown operation on inode ip;
    524  * inode must be locked prior to call.
    525  */
    526 static int
    527 ptyfs_chown(struct vnode *vp, uid_t uid, gid_t gid, struct ucred *cred,
    528     struct proc *p)
    529 {
    530 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    531 	int		error;
    532 
    533 	if (uid == (uid_t)VNOVAL)
    534 		uid = ptyfs->ptyfs_uid;
    535 	if (gid == (gid_t)VNOVAL)
    536 		gid = ptyfs->ptyfs_gid;
    537 	/*
    538 	 * If we don't own the file, are trying to change the owner
    539 	 * of the file, or are not a member of the target group,
    540 	 * the caller's credentials must imply super-user privilege
    541 	 * or the call fails.
    542 	 */
    543 	if ((cred->cr_uid != ptyfs->ptyfs_uid || uid != ptyfs->ptyfs_uid ||
    544 	    (gid != ptyfs->ptyfs_gid &&
    545 	     !(cred->cr_gid == gid || groupmember((gid_t)gid, cred)))) &&
    546 	    ((error = suser(cred, &p->p_acflag)) != 0))
    547 		return error;
    548 
    549 	ptyfs->ptyfs_gid = gid;
    550 	ptyfs->ptyfs_uid = uid;
    551 	return 0;
    552 }
    553 
    554 /*
    555  * implement access checking.
    556  *
    557  * actually, the check for super-user is slightly
    558  * broken since it will allow read access to write-only
    559  * objects.  this doesn't cause any particular trouble
    560  * but does mean that the i/o entry points need to check
    561  * that the operation really does make sense.
    562  */
    563 int
    564 ptyfs_access(void *v)
    565 {
    566 	struct vop_access_args /* {
    567 		struct vnode *a_vp;
    568 		int a_mode;
    569 		struct ucred *a_cred;
    570 		struct proc *a_p;
    571 	} */ *ap = v;
    572 	struct vattr va;
    573 	int error;
    574 
    575 	if ((error = VOP_GETATTR(ap->a_vp, &va, ap->a_cred, ap->a_p)) != 0)
    576 		return error;
    577 
    578 	return vaccess(va.va_type, va.va_mode,
    579 	    va.va_uid, va.va_gid, ap->a_mode, ap->a_cred);
    580 }
    581 
    582 /*
    583  * lookup.  this is incredibly complicated in the
    584  * general case, however for most pseudo-filesystems
    585  * very little needs to be done.
    586  *
    587  * Locking isn't hard here, just poorly documented.
    588  *
    589  * If we're looking up ".", just vref the parent & return it.
    590  *
    591  * If we're looking up "..", unlock the parent, and lock "..". If everything
    592  * went ok, and we're on the last component and the caller requested the
    593  * parent locked, try to re-lock the parent. We do this to prevent lock
    594  * races.
    595  *
    596  * For anything else, get the needed node. Then unlock the parent if not
    597  * the last component or not LOCKPARENT (i.e. if we wouldn't re-lock the
    598  * parent in the .. case).
    599  *
    600  * We try to exit with the parent locked in error cases.
    601  */
    602 int
    603 ptyfs_lookup(void *v)
    604 {
    605 	struct vop_lookup_args /* {
    606 		struct vnode * a_dvp;
    607 		struct vnode ** a_vpp;
    608 		struct componentname * a_cnp;
    609 	} */ *ap = v;
    610 	struct componentname *cnp = ap->a_cnp;
    611 	struct vnode **vpp = ap->a_vpp;
    612 	struct vnode *dvp = ap->a_dvp;
    613 	const char *pname = cnp->cn_nameptr;
    614 	struct ptyfsnode *ptyfs;
    615 	int pty, error, wantpunlock;
    616 
    617 	*vpp = NULL;
    618 	cnp->cn_flags &= ~PDIRUNLOCK;
    619 
    620 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
    621 		return EROFS;
    622 
    623 	if (cnp->cn_namelen == 1 && *pname == '.') {
    624 		*vpp = dvp;
    625 		VREF(dvp);
    626 		return 0;
    627 	}
    628 
    629 	wantpunlock = ~cnp->cn_flags & (LOCKPARENT | ISLASTCN);
    630 	ptyfs = VTOPTYFS(dvp);
    631 	switch (ptyfs->ptyfs_type) {
    632 	case PTYFSroot:
    633 		/*
    634 		 * Shouldn't get here with .. in the root node.
    635 		 */
    636 		if (cnp->cn_flags & ISDOTDOT)
    637 			return EIO;
    638 
    639 		pty = atoi(pname, cnp->cn_namelen);
    640 
    641 		if (pty < 0 || pty >= npty || pty_isfree(pty, 1))
    642 			break;
    643 
    644 		error = ptyfs_allocvp(dvp->v_mount, vpp, PTYFSpts, pty,
    645 		    curproc);
    646 		if (error == 0 && wantpunlock) {
    647 			VOP_UNLOCK(dvp, 0);
    648 			cnp->cn_flags |= PDIRUNLOCK;
    649 		}
    650 		return error;
    651 
    652 	default:
    653 		return ENOTDIR;
    654 	}
    655 
    656 	return cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS;
    657 }
    658 
    659 /*
    660  * readdir returns directory entries from ptyfsnode (vp).
    661  *
    662  * the strategy here with ptyfs is to generate a single
    663  * directory entry at a time (struct dirent) and then
    664  * copy that out to userland using uiomove.  a more efficent
    665  * though more complex implementation, would try to minimize
    666  * the number of calls to uiomove().  for ptyfs, this is
    667  * hardly worth the added code complexity.
    668  *
    669  * this should just be done through read()
    670  */
    671 int
    672 ptyfs_readdir(void *v)
    673 {
    674 	struct vop_readdir_args /* {
    675 		struct vnode *a_vp;
    676 		struct uio *a_uio;
    677 		struct ucred *a_cred;
    678 		int *a_eofflag;
    679 		off_t **a_cookies;
    680 		int *a_ncookies;
    681 	} */ *ap = v;
    682 	struct uio *uio = ap->a_uio;
    683 	struct dirent d;
    684 	struct ptyfsnode *ptyfs;
    685 	off_t i;
    686 	int error;
    687 	off_t *cookies = NULL;
    688 	int ncookies;
    689 	struct vnode *vp;
    690 	int nc = 0;
    691 
    692 	vp = ap->a_vp;
    693 	ptyfs = VTOPTYFS(vp);
    694 
    695 	if (uio->uio_resid < UIO_MX)
    696 		return EINVAL;
    697 	if (uio->uio_offset < 0)
    698 		return EINVAL;
    699 
    700 	error = 0;
    701 	i = uio->uio_offset;
    702 	(void)memset(&d, 0, sizeof(d));
    703 	d.d_reclen = UIO_MX;
    704 	ncookies = uio->uio_resid / UIO_MX;
    705 
    706 	switch (ptyfs->ptyfs_type) {
    707 	case PTYFSroot: /* root */
    708 
    709 		if (i >= npty)
    710 			return 0;
    711 
    712 		if (ap->a_ncookies) {
    713 			ncookies = min(ncookies, (npty + 2 - i));
    714 			cookies = malloc(ncookies * sizeof (off_t),
    715 			    M_TEMP, M_WAITOK);
    716 			*ap->a_cookies = cookies;
    717 		}
    718 
    719 		for (; i < 2; i++) {
    720 			switch (i) {
    721 			case 0:		/* `.' */
    722 			case 1:		/* `..' */
    723 				d.d_fileno = PTYFS_FILENO(0, PTYFSroot);
    724 				d.d_namlen = i + 1;
    725 				(void)memcpy(d.d_name, "..", d.d_namlen);
    726 				d.d_name[i + 1] = '\0';
    727 				d.d_type = DT_DIR;
    728 				break;
    729 			}
    730 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
    731 				break;
    732 			if (cookies)
    733 				*cookies++ = i + 1;
    734 			nc++;
    735 		}
    736 		if (error) {
    737 			ncookies = nc;
    738 			break;
    739 		}
    740 		for (; uio->uio_resid >= UIO_MX && i < npty; i++) {
    741 			/* check for used ptys */
    742 			if (pty_isfree(i - 2, 1))
    743 				continue;
    744 
    745 			d.d_fileno = PTYFS_FILENO(i - 2, PTYFSpts);
    746 			d.d_namlen = snprintf(d.d_name, sizeof(d.d_name),
    747 			    "%lld", (long long)(i - 2));
    748 			d.d_type = DT_CHR;
    749 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
    750 				break;
    751 			if (cookies)
    752 				*cookies++ = i + 1;
    753 			nc++;
    754 		}
    755 		ncookies = nc;
    756 		break;
    757 
    758 	default:
    759 		error = ENOTDIR;
    760 		break;
    761 	}
    762 
    763 	if (ap->a_ncookies) {
    764 		if (error) {
    765 			if (cookies)
    766 				free(*ap->a_cookies, M_TEMP);
    767 			*ap->a_ncookies = 0;
    768 			*ap->a_cookies = NULL;
    769 		} else
    770 			*ap->a_ncookies = ncookies;
    771 	}
    772 	uio->uio_offset = i;
    773 	return error;
    774 }
    775 
    776 int
    777 ptyfs_open(void *v)
    778 {
    779 	struct vop_open_args /* {
    780 		struct vnode *a_vp;
    781 		int  a_mode;
    782 		struct ucred *a_cred;
    783 		struct proc *a_p;
    784 	} */ *ap = v;
    785 	struct vnode *vp = ap->a_vp;
    786 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    787 
    788 	ptyfs->ptyfs_flag |= PTYFS_CHANGE|PTYFS_ACCESS;
    789 	switch (ptyfs->ptyfs_type) {
    790 	case PTYFSpts:
    791 	case PTYFSptc:
    792 		return spec_open(v);
    793 	case PTYFSroot:
    794 		return 0;
    795 	default:
    796 		return EINVAL;
    797 	}
    798 }
    799 
    800 int
    801 ptyfs_close(void *v)
    802 {
    803 	struct vop_close_args /* {
    804 		struct vnode *a_vp;
    805 		int  a_fflag;
    806 		struct ucred *a_cred;
    807 		struct proc *a_p;
    808 	} */ *ap = v;
    809 	struct vnode *vp = ap->a_vp;
    810 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    811         struct timespec ts;
    812 	ptyfs_time(ptyfs, &ts, &ts);
    813 
    814         simple_lock(&vp->v_interlock);
    815         if (vp->v_usecount > 1) {
    816 		TIMEVAL_TO_TIMESPEC(&time, &ts);
    817 		ptyfs_time(ptyfs, &ts, &ts);
    818         }
    819         simple_unlock(&vp->v_interlock);
    820 
    821 	switch (ptyfs->ptyfs_type) {
    822 	case PTYFSpts:
    823 	case PTYFSptc:
    824 		return spec_close(v);
    825 	case PTYFSroot:
    826 		return 0;
    827 	default:
    828 		return EINVAL;
    829 	}
    830 }
    831 
    832 int
    833 ptyfs_read(void *v)
    834 {
    835 	struct vop_read_args /* {
    836 		struct vnode *a_vp;
    837 		struct uio *a_uio;
    838 		int  a_ioflag;
    839 		struct ucred *a_cred;
    840 	} */ *ap = v;
    841 	struct vnode *vp = ap->a_vp;
    842 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    843 	int error;
    844 
    845 	ptyfs->ptyfs_flag |= PTYFS_ACCESS;
    846 	switch (ptyfs->ptyfs_type) {
    847 	case PTYFSpts:
    848 		VOP_UNLOCK(vp, 0);
    849 		error = (*pts_cdevsw.d_read)(vp->v_rdev, ap->a_uio,
    850 		    ap->a_ioflag);
    851 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
    852 		return error;
    853 	case PTYFSptc:
    854 		VOP_UNLOCK(vp, 0);
    855 		error = (*ptc_cdevsw.d_read)(vp->v_rdev, ap->a_uio,
    856 		    ap->a_ioflag);
    857 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
    858 		return error;
    859 	default:
    860 		return EOPNOTSUPP;
    861 	}
    862 }
    863 
    864 int
    865 ptyfs_write(void *v)
    866 {
    867 	struct vop_write_args /* {
    868 		struct vnode *a_vp;
    869 		struct uio *a_uio;
    870 		int  a_ioflag;
    871 		struct ucred *a_cred;
    872 	} */ *ap = v;
    873 	int error;
    874 	struct vnode *vp = ap->a_vp;
    875 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    876 
    877 	ptyfs->ptyfs_flag |= PTYFS_MODIFY;
    878 	switch (ptyfs->ptyfs_type) {
    879 	case PTYFSpts:
    880 		VOP_UNLOCK(vp, 0);
    881 		error = (*pts_cdevsw.d_write)(vp->v_rdev, ap->a_uio,
    882 		    ap->a_ioflag);
    883 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
    884 		return error;
    885 	case PTYFSptc:
    886 		VOP_UNLOCK(vp, 0);
    887 		error = (*ptc_cdevsw.d_write)(vp->v_rdev, ap->a_uio,
    888 		    ap->a_ioflag);
    889 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
    890 		return error;
    891 	default:
    892 		return EOPNOTSUPP;
    893 	}
    894 }
    895 
    896 int
    897 ptyfs_ioctl(void *v)
    898 {
    899 	struct vop_ioctl_args /* {
    900 		struct vnode *a_vp;
    901 		u_long a_command;
    902 		void *a_data;
    903 		int  a_fflag;
    904 		struct ucred *a_cred;
    905 		struct proc *a_p;
    906 	} */ *ap = v;
    907 	struct vnode *vp = ap->a_vp;
    908 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    909 
    910 	switch (ptyfs->ptyfs_type) {
    911 	case PTYFSpts:
    912 		return (*pts_cdevsw.d_ioctl)(vp->v_rdev, ap->a_command,
    913 		    ap->a_data, ap->a_fflag, ap->a_p);
    914 	case PTYFSptc:
    915 		return (*ptc_cdevsw.d_ioctl)(vp->v_rdev, ap->a_command,
    916 		    ap->a_data, ap->a_fflag, ap->a_p);
    917 	default:
    918 		return EOPNOTSUPP;
    919 	}
    920 }
    921 
    922 int
    923 ptyfs_poll(void *v)
    924 {
    925 	struct vop_poll_args /* {
    926 		struct vnode *a_vp;
    927 		int a_events;
    928 		struct proc *a_p;
    929 	} */ *ap = v;
    930 	struct vnode *vp = ap->a_vp;
    931 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    932 
    933 	switch (ptyfs->ptyfs_type) {
    934 	case PTYFSpts:
    935 		return (*pts_cdevsw.d_poll)(vp->v_rdev, ap->a_events, ap->a_p);
    936 	case PTYFSptc:
    937 		return (*ptc_cdevsw.d_poll)(vp->v_rdev, ap->a_events, ap->a_p);
    938 	default:
    939 		return genfs_poll(v);
    940 	}
    941 }
    942 
    943 int
    944 ptyfs_kqfilter(void *v)
    945 {
    946 	struct vop_kqfilter_args /* {
    947 		struct vnode *a_vp;
    948 		struct knote *a_kn;
    949 	} */ *ap = v;
    950 	struct vnode *vp = ap->a_vp;
    951 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    952 
    953 	switch (ptyfs->ptyfs_type) {
    954 	case PTYFSpts:
    955 		return (*pts_cdevsw.d_kqfilter)(vp->v_rdev, ap->a_kn);
    956 	case PTYFSptc:
    957 		return (*ptc_cdevsw.d_kqfilter)(vp->v_rdev, ap->a_kn);
    958 	default:
    959 		return genfs_kqfilter(v);
    960 	}
    961 }
    962 
    963 int
    964 ptyfs_update(v)
    965 	void *v;
    966 {
    967 	struct vop_update_args /* {
    968 		struct vnode *a_vp;
    969 		struct timespec *a_access;
    970 		struct timespec *a_modify;
    971 		int a_flags;
    972 	} */ *ap = v;
    973 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
    974 	struct timespec ts;
    975 
    976 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
    977 		return 0;
    978 
    979 	TIMEVAL_TO_TIMESPEC(&time, &ts);
    980 	if (ap->a_access == NULL)
    981 		ap->a_access = &ts;
    982 	if (ap->a_modify == NULL)
    983 		ap->a_modify = &ts;
    984 	ptyfs_time(ptyfs, ap->a_access, ap->a_modify);
    985 	return 0;
    986 }
    987 
    988 static void
    989 ptyfs_time(struct ptyfsnode *ptyfs, struct timespec *atime,
    990     struct timespec *mtime)
    991 {
    992 	if (ptyfs->ptyfs_flag & PTYFS_MODIFY) {
    993 		ptyfs->ptyfs_mtime = *mtime;
    994 		ptyfs->ptyfs_atime = *atime;
    995 	} else if (ptyfs->ptyfs_flag & PTYFS_ACCESS)
    996 		ptyfs->ptyfs_atime = *atime;
    997 	if (ptyfs->ptyfs_flag & PTYFS_CHANGE)
    998 		ptyfs->ptyfs_ctime = *atime;
    999 	ptyfs->ptyfs_flag = 0;
   1000 }
   1001 
   1002 /*
   1003  * convert decimal ascii to int
   1004  */
   1005 static int
   1006 atoi(const char *b, size_t len)
   1007 {
   1008 	int p = 0;
   1009 
   1010 	while (len--) {
   1011 		char c = *b++;
   1012 		if (c < '0' || c > '9')
   1013 			return -1;
   1014 		p = 10 * p + (c - '0');
   1015 	}
   1016 
   1017 	return p;
   1018 }
   1019 
   1020 /*
   1021  * Return the number of decimal digits
   1022  */
   1023 static u_int
   1024 digits(u_int i)
   1025 {
   1026 	u_int d;
   1027 	for (d = 1; i != 0; d++)
   1028 		i /= 10;
   1029 	return d;
   1030 }
   1031