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ptyfs_vnops.c revision 1.27
      1 /*	$NetBSD: ptyfs_vnops.c,v 1.27 2008/01/02 11:48:43 ad 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 1.27 2008/01/02 11:48:43 ad 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 #include <sys/kauth.h>
    100 
    101 #include <uvm/uvm_extern.h>	/* for PAGE_SIZE */
    102 
    103 #include <machine/reg.h>
    104 
    105 #include <fs/ptyfs/ptyfs.h>
    106 #include <miscfs/genfs/genfs.h>
    107 #include <miscfs/specfs/specdev.h>
    108 
    109 MALLOC_DECLARE(M_PTYFSTMP);
    110 
    111 /*
    112  * Vnode Operations.
    113  *
    114  */
    115 
    116 int	ptyfs_lookup	(void *);
    117 #define	ptyfs_create	genfs_eopnotsupp
    118 #define	ptyfs_mknod	genfs_eopnotsupp
    119 int	ptyfs_open	(void *);
    120 int	ptyfs_close	(void *);
    121 int	ptyfs_access	(void *);
    122 int	ptyfs_getattr	(void *);
    123 int	ptyfs_setattr	(void *);
    124 int	ptyfs_read	(void *);
    125 int	ptyfs_write	(void *);
    126 #define	ptyfs_fcntl	genfs_fcntl
    127 int	ptyfs_ioctl	(void *);
    128 int	ptyfs_poll	(void *);
    129 int	ptyfs_kqfilter	(void *);
    130 #define ptyfs_revoke	genfs_revoke
    131 #define	ptyfs_mmap	genfs_eopnotsupp
    132 #define	ptyfs_fsync	genfs_nullop
    133 #define	ptyfs_seek	genfs_nullop
    134 #define	ptyfs_remove	genfs_eopnotsupp
    135 #define	ptyfs_link	genfs_abortop
    136 #define	ptyfs_rename	genfs_eopnotsupp
    137 #define	ptyfs_mkdir	genfs_eopnotsupp
    138 #define	ptyfs_rmdir	genfs_eopnotsupp
    139 #define	ptyfs_symlink	genfs_abortop
    140 int	ptyfs_readdir	(void *);
    141 #define	ptyfs_readlink	genfs_eopnotsupp
    142 #define	ptyfs_abortop	genfs_abortop
    143 int	ptyfs_reclaim	(void *);
    144 #define	ptyfs_lock	genfs_lock
    145 #define	ptyfs_unlock	genfs_unlock
    146 #define	ptyfs_bmap	genfs_badop
    147 #define	ptyfs_strategy	genfs_badop
    148 int	ptyfs_print	(void *);
    149 int	ptyfs_pathconf	(void *);
    150 #define	ptyfs_islocked	genfs_islocked
    151 #define	ptyfs_advlock	genfs_einval
    152 #define	ptyfs_bwrite	genfs_eopnotsupp
    153 #define ptyfs_putpages	genfs_null_putpages
    154 
    155 static int ptyfs_update(struct vnode *, const struct timespec *,
    156     const struct timespec *, int);
    157 static int ptyfs_chown(struct vnode *, uid_t, gid_t, kauth_cred_t,
    158     struct lwp *);
    159 static int ptyfs_chmod(struct vnode *, mode_t, kauth_cred_t, struct lwp *);
    160 static int atoi(const char *, size_t);
    161 
    162 /*
    163  * ptyfs vnode operations.
    164  */
    165 int (**ptyfs_vnodeop_p)(void *);
    166 const struct vnodeopv_entry_desc ptyfs_vnodeop_entries[] = {
    167 	{ &vop_default_desc, vn_default_error },
    168 	{ &vop_lookup_desc, ptyfs_lookup },		/* lookup */
    169 	{ &vop_create_desc, ptyfs_create },		/* create */
    170 	{ &vop_mknod_desc, ptyfs_mknod },		/* mknod */
    171 	{ &vop_open_desc, ptyfs_open },			/* open */
    172 	{ &vop_close_desc, ptyfs_close },		/* close */
    173 	{ &vop_access_desc, ptyfs_access },		/* access */
    174 	{ &vop_getattr_desc, ptyfs_getattr },		/* getattr */
    175 	{ &vop_setattr_desc, ptyfs_setattr },		/* setattr */
    176 	{ &vop_read_desc, ptyfs_read },			/* read */
    177 	{ &vop_write_desc, ptyfs_write },		/* write */
    178 	{ &vop_ioctl_desc, ptyfs_ioctl },		/* ioctl */
    179 	{ &vop_fcntl_desc, ptyfs_fcntl },		/* fcntl */
    180 	{ &vop_poll_desc, ptyfs_poll },			/* poll */
    181 	{ &vop_kqfilter_desc, ptyfs_kqfilter },		/* kqfilter */
    182 	{ &vop_revoke_desc, ptyfs_revoke },		/* revoke */
    183 	{ &vop_mmap_desc, ptyfs_mmap },			/* mmap */
    184 	{ &vop_fsync_desc, ptyfs_fsync },		/* fsync */
    185 	{ &vop_seek_desc, ptyfs_seek },			/* seek */
    186 	{ &vop_remove_desc, ptyfs_remove },		/* remove */
    187 	{ &vop_link_desc, ptyfs_link },			/* link */
    188 	{ &vop_rename_desc, ptyfs_rename },		/* rename */
    189 	{ &vop_mkdir_desc, ptyfs_mkdir },		/* mkdir */
    190 	{ &vop_rmdir_desc, ptyfs_rmdir },		/* rmdir */
    191 	{ &vop_symlink_desc, ptyfs_symlink },		/* symlink */
    192 	{ &vop_readdir_desc, ptyfs_readdir },		/* readdir */
    193 	{ &vop_readlink_desc, ptyfs_readlink },		/* readlink */
    194 	{ &vop_abortop_desc, ptyfs_abortop },		/* abortop */
    195 	{ &vop_inactive_desc, spec_inactive },		/* inactive */
    196 	{ &vop_reclaim_desc, ptyfs_reclaim },		/* reclaim */
    197 	{ &vop_lock_desc, ptyfs_lock },			/* lock */
    198 	{ &vop_unlock_desc, ptyfs_unlock },		/* unlock */
    199 	{ &vop_bmap_desc, ptyfs_bmap },			/* bmap */
    200 	{ &vop_strategy_desc, ptyfs_strategy },		/* strategy */
    201 	{ &vop_print_desc, ptyfs_print },		/* print */
    202 	{ &vop_islocked_desc, ptyfs_islocked },		/* islocked */
    203 	{ &vop_pathconf_desc, ptyfs_pathconf },		/* pathconf */
    204 	{ &vop_advlock_desc, ptyfs_advlock },		/* advlock */
    205 	{ &vop_bwrite_desc, ptyfs_bwrite },		/* bwrite */
    206 	{ &vop_putpages_desc, ptyfs_putpages },		/* putpages */
    207 	{ NULL, NULL }
    208 };
    209 const struct vnodeopv_desc ptyfs_vnodeop_opv_desc =
    210 	{ &ptyfs_vnodeop_p, ptyfs_vnodeop_entries };
    211 
    212 /*
    213  * _reclaim is called when getnewvnode()
    214  * wants to make use of an entry on the vnode
    215  * free list.  at this time the filesystem needs
    216  * to free any private data and remove the node
    217  * from any private lists.
    218  */
    219 int
    220 ptyfs_reclaim(void *v)
    221 {
    222 	struct vop_reclaim_args /* {
    223 		struct vnode *a_vp;
    224 	} */ *ap = v;
    225 	return ptyfs_freevp(ap->a_vp);
    226 }
    227 
    228 /*
    229  * Return POSIX pathconf information applicable to special devices.
    230  */
    231 int
    232 ptyfs_pathconf(void *v)
    233 {
    234 	struct vop_pathconf_args /* {
    235 		struct vnode *a_vp;
    236 		int a_name;
    237 		register_t *a_retval;
    238 	} */ *ap = v;
    239 
    240 	switch (ap->a_name) {
    241 	case _PC_LINK_MAX:
    242 		*ap->a_retval = LINK_MAX;
    243 		return 0;
    244 	case _PC_MAX_CANON:
    245 		*ap->a_retval = MAX_CANON;
    246 		return 0;
    247 	case _PC_MAX_INPUT:
    248 		*ap->a_retval = MAX_INPUT;
    249 		return 0;
    250 	case _PC_PIPE_BUF:
    251 		*ap->a_retval = PIPE_BUF;
    252 		return 0;
    253 	case _PC_CHOWN_RESTRICTED:
    254 		*ap->a_retval = 1;
    255 		return 0;
    256 	case _PC_VDISABLE:
    257 		*ap->a_retval = _POSIX_VDISABLE;
    258 		return 0;
    259 	case _PC_SYNC_IO:
    260 		*ap->a_retval = 1;
    261 		return 0;
    262 	default:
    263 		return EINVAL;
    264 	}
    265 }
    266 
    267 /*
    268  * _print is used for debugging.
    269  * just print a readable description
    270  * of (vp).
    271  */
    272 int
    273 ptyfs_print(void *v)
    274 {
    275 	struct vop_print_args /* {
    276 		struct vnode *a_vp;
    277 	} */ *ap = v;
    278 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
    279 
    280 	printf("tag VT_PTYFS, type %d, pty %d\n",
    281 	    ptyfs->ptyfs_type, ptyfs->ptyfs_pty);
    282 	return 0;
    283 }
    284 
    285 /*
    286  * Invent attributes for ptyfsnode (vp) and store
    287  * them in (vap).
    288  * Directories lengths are returned as zero since
    289  * any real length would require the genuine size
    290  * to be computed, and nothing cares anyway.
    291  *
    292  * this is relatively minimal for ptyfs.
    293  */
    294 int
    295 ptyfs_getattr(void *v)
    296 {
    297 	struct vop_getattr_args /* {
    298 		struct vnode *a_vp;
    299 		struct vattr *a_vap;
    300 		kauth_cred_t a_cred;
    301 	} */ *ap = v;
    302 	struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
    303 	struct vattr *vap = ap->a_vap;
    304 
    305 	PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
    306 
    307 	/* start by zeroing out the attributes */
    308 	VATTR_NULL(vap);
    309 
    310 	/* next do all the common fields */
    311 	vap->va_type = ap->a_vp->v_type;
    312 	vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
    313 	vap->va_fileid = ptyfs->ptyfs_fileno;
    314 	vap->va_gen = 0;
    315 	vap->va_flags = 0;
    316 	vap->va_nlink = 1;
    317 	vap->va_blocksize = PAGE_SIZE;
    318 
    319 	vap->va_atime = ptyfs->ptyfs_atime;
    320 	vap->va_mtime = ptyfs->ptyfs_mtime;
    321 	vap->va_ctime = ptyfs->ptyfs_ctime;
    322 	vap->va_birthtime = ptyfs->ptyfs_birthtime;
    323 	vap->va_mode = ptyfs->ptyfs_mode;
    324 	vap->va_flags = ptyfs->ptyfs_flags;
    325 	vap->va_uid = ptyfs->ptyfs_uid;
    326 	vap->va_gid = ptyfs->ptyfs_gid;
    327 
    328 	switch (ptyfs->ptyfs_type) {
    329 	case PTYFSpts:
    330 	case PTYFSptc:
    331 		if (pty_isfree(ptyfs->ptyfs_pty, 1))
    332 			return ENOENT;
    333 		vap->va_bytes = vap->va_size = 0;
    334 		vap->va_rdev = ap->a_vp->v_rdev;
    335 		break;
    336 	case PTYFSroot:
    337 		vap->va_rdev = 0;
    338 		vap->va_bytes = vap->va_size = DEV_BSIZE;
    339 		break;
    340 
    341 	default:
    342 		return EOPNOTSUPP;
    343 	}
    344 
    345 	return 0;
    346 }
    347 
    348 /*ARGSUSED*/
    349 int
    350 ptyfs_setattr(void *v)
    351 {
    352 	struct vop_setattr_args /* {
    353 		struct vnodeop_desc *a_desc;
    354 		struct vnode *a_vp;
    355 		struct vattr *a_vap;
    356 		kauth_cred_t a_cred;
    357 	} */ *ap = v;
    358 	struct vnode *vp = ap->a_vp;
    359 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    360 	struct vattr *vap = ap->a_vap;
    361 	kauth_cred_t cred = ap->a_cred;
    362 	struct lwp *l = curlwp;
    363 	int error;
    364 
    365 	if (vap->va_size != VNOVAL) {
    366  		switch (ptyfs->ptyfs_type) {
    367  		case PTYFSroot:
    368  			return EISDIR;
    369  		case PTYFSpts:
    370  		case PTYFSptc:
    371 			break;
    372 		default:
    373 			return EINVAL;
    374 		}
    375 	}
    376 
    377 	if (vap->va_flags != VNOVAL) {
    378 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    379 			return EROFS;
    380 		if (kauth_cred_geteuid(cred) != ptyfs->ptyfs_uid &&
    381 		    (error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
    382 		    NULL)) != 0)
    383 			return error;
    384 		/* Immutable and append-only flags are not supported on ptyfs. */
    385 		if (vap->va_flags & (IMMUTABLE | APPEND))
    386 			return EINVAL;
    387 		if (kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER, NULL) == 0) {
    388 			/* Snapshot flag cannot be set or cleared */
    389 			if ((vap->va_flags & SF_SNAPSHOT) !=
    390 			    (ptyfs->ptyfs_flags & SF_SNAPSHOT))
    391 				return EPERM;
    392 			ptyfs->ptyfs_flags = vap->va_flags;
    393 		} else {
    394 			if ((ptyfs->ptyfs_flags & SF_SETTABLE) !=
    395 			    (vap->va_flags & SF_SETTABLE))
    396 				return EPERM;
    397 			ptyfs->ptyfs_flags &= SF_SETTABLE;
    398 			ptyfs->ptyfs_flags |= (vap->va_flags & UF_SETTABLE);
    399 		}
    400 		ptyfs->ptyfs_flag |= PTYFS_CHANGE;
    401 	}
    402 
    403 	/*
    404 	 * Go through the fields and update iff not VNOVAL.
    405 	 */
    406 	if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
    407 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    408 			return EROFS;
    409 		if (ptyfs->ptyfs_type == PTYFSroot)
    410 			return EPERM;
    411 		error = ptyfs_chown(vp, vap->va_uid, vap->va_gid, cred, l);
    412 		if (error)
    413 			return error;
    414 	}
    415 
    416 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL ||
    417 	    vap->va_birthtime.tv_sec != VNOVAL) {
    418 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    419 			return EROFS;
    420 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0)
    421 			return EPERM;
    422 		if (kauth_cred_geteuid(cred) != ptyfs->ptyfs_uid &&
    423 		    (error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
    424 		    NULL)) &&
    425 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
    426 		    (error = VOP_ACCESS(vp, VWRITE, cred)) != 0))
    427 			return (error);
    428 		if (vap->va_atime.tv_sec != VNOVAL)
    429 			if (!(vp->v_mount->mnt_flag & MNT_NOATIME))
    430 				ptyfs->ptyfs_flag |= PTYFS_ACCESS;
    431 		if (vap->va_mtime.tv_sec != VNOVAL)
    432 			ptyfs->ptyfs_flag |= PTYFS_CHANGE | PTYFS_MODIFY;
    433 		if (vap->va_birthtime.tv_sec != VNOVAL)
    434 			ptyfs->ptyfs_birthtime = vap->va_birthtime;
    435 		ptyfs->ptyfs_flag |= PTYFS_CHANGE;
    436 		error = ptyfs_update(vp, &vap->va_atime, &vap->va_mtime, 0);
    437 		if (error)
    438 			return error;
    439 	}
    440 	if (vap->va_mode != (mode_t)VNOVAL) {
    441 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
    442 			return EROFS;
    443 		if (ptyfs->ptyfs_type == PTYFSroot)
    444 			return EPERM;
    445 		if ((ptyfs->ptyfs_flags & SF_SNAPSHOT) != 0 &&
    446 		    (vap->va_mode &
    447 		    (S_IXUSR|S_IWUSR|S_IXGRP|S_IWGRP|S_IXOTH|S_IWOTH)))
    448 			return EPERM;
    449 		error = ptyfs_chmod(vp, vap->va_mode, cred, l);
    450 		if (error)
    451 			return error;
    452 	}
    453 	VN_KNOTE(vp, NOTE_ATTRIB);
    454 	return 0;
    455 }
    456 
    457 /*
    458  * Change the mode on a file.
    459  * Inode must be locked before calling.
    460  */
    461 static int
    462 ptyfs_chmod(struct vnode *vp, mode_t mode, kauth_cred_t cred, struct lwp *l)
    463 {
    464 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    465 	int error;
    466 
    467 	if (kauth_cred_geteuid(cred) != ptyfs->ptyfs_uid &&
    468 	    (error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
    469 	    NULL)) != 0)
    470 		return error;
    471 	ptyfs->ptyfs_mode &= ~ALLPERMS;
    472 	ptyfs->ptyfs_mode |= (mode & ALLPERMS);
    473 	return 0;
    474 }
    475 
    476 /*
    477  * Perform chown operation on inode ip;
    478  * inode must be locked prior to call.
    479  */
    480 static int
    481 ptyfs_chown(struct vnode *vp, uid_t uid, gid_t gid, kauth_cred_t cred,
    482     struct lwp *l)
    483 {
    484 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    485 	int		error, ismember = 0;
    486 
    487 	if (uid == (uid_t)VNOVAL)
    488 		uid = ptyfs->ptyfs_uid;
    489 	if (gid == (gid_t)VNOVAL)
    490 		gid = ptyfs->ptyfs_gid;
    491 	/*
    492 	 * If we don't own the file, are trying to change the owner
    493 	 * of the file, or are not a member of the target group,
    494 	 * the caller's credentials must imply super-user privilege
    495 	 * or the call fails.
    496 	 */
    497 	if ((kauth_cred_geteuid(cred) != ptyfs->ptyfs_uid || uid != ptyfs->ptyfs_uid ||
    498 	    (gid != ptyfs->ptyfs_gid &&
    499 	    !(kauth_cred_getegid(cred) == gid ||
    500 	    (kauth_cred_ismember_gid(cred, gid, &ismember) == 0 && ismember)))) &&
    501 	    ((error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
    502 	    NULL)) != 0))
    503 		return error;
    504 
    505 	ptyfs->ptyfs_gid = gid;
    506 	ptyfs->ptyfs_uid = uid;
    507 	return 0;
    508 }
    509 
    510 /*
    511  * implement access checking.
    512  *
    513  * actually, the check for super-user is slightly
    514  * broken since it will allow read access to write-only
    515  * objects.  this doesn't cause any particular trouble
    516  * but does mean that the i/o entry points need to check
    517  * that the operation really does make sense.
    518  */
    519 int
    520 ptyfs_access(void *v)
    521 {
    522 	struct vop_access_args /* {
    523 		struct vnode *a_vp;
    524 		int a_mode;
    525 		kauth_cred_t a_cred;
    526 	} */ *ap = v;
    527 	struct vattr va;
    528 	int error;
    529 
    530 	if ((error = VOP_GETATTR(ap->a_vp, &va, ap->a_cred)) != 0)
    531 		return error;
    532 
    533 	return vaccess(va.va_type, va.va_mode,
    534 	    va.va_uid, va.va_gid, ap->a_mode, ap->a_cred);
    535 }
    536 
    537 /*
    538  * lookup.  this is incredibly complicated in the
    539  * general case, however for most pseudo-filesystems
    540  * very little needs to be done.
    541  *
    542  * Locking isn't hard here, just poorly documented.
    543  *
    544  * If we're looking up ".", just vref the parent & return it.
    545  *
    546  * If we're looking up "..", unlock the parent, and lock "..". If everything
    547  * went ok, try to re-lock the parent. We do this to prevent lock races.
    548  *
    549  * For anything else, get the needed node.
    550  *
    551  * We try to exit with the parent locked in error cases.
    552  */
    553 int
    554 ptyfs_lookup(void *v)
    555 {
    556 	struct vop_lookup_args /* {
    557 		struct vnode * a_dvp;
    558 		struct vnode ** a_vpp;
    559 		struct componentname * a_cnp;
    560 	} */ *ap = v;
    561 	struct componentname *cnp = ap->a_cnp;
    562 	struct vnode **vpp = ap->a_vpp;
    563 	struct vnode *dvp = ap->a_dvp;
    564 	const char *pname = cnp->cn_nameptr;
    565 	struct ptyfsnode *ptyfs;
    566 	int pty, error;
    567 
    568 	*vpp = NULL;
    569 
    570 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
    571 		return EROFS;
    572 
    573 	if (cnp->cn_namelen == 1 && *pname == '.') {
    574 		*vpp = dvp;
    575 		VREF(dvp);
    576 		return 0;
    577 	}
    578 
    579 	ptyfs = VTOPTYFS(dvp);
    580 	switch (ptyfs->ptyfs_type) {
    581 	case PTYFSroot:
    582 		/*
    583 		 * Shouldn't get here with .. in the root node.
    584 		 */
    585 		if (cnp->cn_flags & ISDOTDOT)
    586 			return EIO;
    587 
    588 		pty = atoi(pname, cnp->cn_namelen);
    589 
    590 		if (pty < 0 || pty >= npty || pty_isfree(pty, 1))
    591 			break;
    592 
    593 		error = ptyfs_allocvp(dvp->v_mount, vpp, PTYFSpts, pty,
    594 		    curlwp);
    595 		return error;
    596 
    597 	default:
    598 		return ENOTDIR;
    599 	}
    600 
    601 	return cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS;
    602 }
    603 
    604 /*
    605  * readdir returns directory entries from ptyfsnode (vp).
    606  *
    607  * the strategy here with ptyfs is to generate a single
    608  * directory entry at a time (struct dirent) and then
    609  * copy that out to userland using uiomove.  a more efficent
    610  * though more complex implementation, would try to minimize
    611  * the number of calls to uiomove().  for ptyfs, this is
    612  * hardly worth the added code complexity.
    613  *
    614  * this should just be done through read()
    615  */
    616 int
    617 ptyfs_readdir(void *v)
    618 {
    619 	struct vop_readdir_args /* {
    620 		struct vnode *a_vp;
    621 		struct uio *a_uio;
    622 		kauth_cred_t a_cred;
    623 		int *a_eofflag;
    624 		off_t **a_cookies;
    625 		int *a_ncookies;
    626 	} */ *ap = v;
    627 	struct uio *uio = ap->a_uio;
    628 	struct dirent *dp;
    629 	struct ptyfsnode *ptyfs;
    630 	off_t i;
    631 	int error;
    632 	off_t *cookies = NULL;
    633 	int ncookies;
    634 	struct vnode *vp;
    635 	int nc = 0;
    636 
    637 	vp = ap->a_vp;
    638 	ptyfs = VTOPTYFS(vp);
    639 
    640 	if (uio->uio_resid < UIO_MX)
    641 		return EINVAL;
    642 	if (uio->uio_offset < 0)
    643 		return EINVAL;
    644 
    645 	dp = malloc(sizeof(struct dirent), M_PTYFSTMP, M_WAITOK | M_ZERO);
    646 
    647 	error = 0;
    648 	i = uio->uio_offset;
    649 	dp->d_reclen = UIO_MX;
    650 	ncookies = uio->uio_resid / UIO_MX;
    651 
    652 	if (ptyfs->ptyfs_type != PTYFSroot) {
    653 		error = ENOTDIR;
    654 		goto out;
    655 	}
    656 
    657 	if (i >= npty)
    658 		goto out;
    659 
    660 	if (ap->a_ncookies) {
    661 		ncookies = min(ncookies, (npty + 2 - i));
    662 		cookies = malloc(ncookies * sizeof (off_t),
    663 		    M_TEMP, M_WAITOK);
    664 		*ap->a_cookies = cookies;
    665 	}
    666 
    667 	for (; i < 2; i++) {
    668 		/* `.' and/or `..' */
    669 		dp->d_fileno = PTYFS_FILENO(0, PTYFSroot);
    670 		dp->d_namlen = i + 1;
    671 		(void)memcpy(dp->d_name, "..", dp->d_namlen);
    672 		dp->d_name[i + 1] = '\0';
    673 		dp->d_type = DT_DIR;
    674 		if ((error = uiomove(dp, UIO_MX, uio)) != 0)
    675 			goto out;
    676 		if (cookies)
    677 			*cookies++ = i + 1;
    678 		nc++;
    679 	}
    680 	for (; uio->uio_resid >= UIO_MX && i < npty; i++) {
    681 		/* check for used ptys */
    682 		if (pty_isfree(i - 2, 1))
    683 			continue;
    684 
    685 		dp->d_fileno = PTYFS_FILENO(i - 2, PTYFSpts);
    686 		dp->d_namlen = snprintf(dp->d_name, sizeof(dp->d_name),
    687 		    "%lld", (long long)(i - 2));
    688 		dp->d_type = DT_CHR;
    689 		if ((error = uiomove(dp, UIO_MX, uio)) != 0)
    690 			goto out;
    691 		if (cookies)
    692 			*cookies++ = i + 1;
    693 		nc++;
    694 	}
    695 
    696 out:
    697 	/* not pertinent in error cases */
    698 	ncookies = nc;
    699 
    700 	if (ap->a_ncookies) {
    701 		if (error) {
    702 			if (cookies)
    703 				free(*ap->a_cookies, M_TEMP);
    704 			*ap->a_ncookies = 0;
    705 			*ap->a_cookies = NULL;
    706 		} else
    707 			*ap->a_ncookies = ncookies;
    708 	}
    709 	uio->uio_offset = i;
    710 	free(dp, M_PTYFSTMP);
    711 	return error;
    712 }
    713 
    714 int
    715 ptyfs_open(void *v)
    716 {
    717 	struct vop_open_args /* {
    718 		struct vnode *a_vp;
    719 		int  a_mode;
    720 		kauth_cred_t a_cred;
    721 	} */ *ap = v;
    722 	struct vnode *vp = ap->a_vp;
    723 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    724 
    725 	ptyfs->ptyfs_flag |= PTYFS_CHANGE|PTYFS_ACCESS;
    726 	switch (ptyfs->ptyfs_type) {
    727 	case PTYFSpts:
    728 	case PTYFSptc:
    729 		return spec_open(v);
    730 	case PTYFSroot:
    731 		return 0;
    732 	default:
    733 		return EINVAL;
    734 	}
    735 }
    736 
    737 int
    738 ptyfs_close(void *v)
    739 {
    740 	struct vop_close_args /* {
    741 		struct vnode *a_vp;
    742 		int  a_fflag;
    743 		kauth_cred_t a_cred;
    744 	} */ *ap = v;
    745 	struct vnode *vp = ap->a_vp;
    746 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    747 
    748 	mutex_enter(&vp->v_interlock);
    749 	if (vp->v_usecount > 1)
    750 		PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
    751 	mutex_exit(&vp->v_interlock);
    752 
    753 	switch (ptyfs->ptyfs_type) {
    754 	case PTYFSpts:
    755 	case PTYFSptc:
    756 		return spec_close(v);
    757 	case PTYFSroot:
    758 		return 0;
    759 	default:
    760 		return EINVAL;
    761 	}
    762 }
    763 
    764 int
    765 ptyfs_read(void *v)
    766 {
    767 	struct vop_read_args /* {
    768 		struct vnode *a_vp;
    769 		struct uio *a_uio;
    770 		int  a_ioflag;
    771 		kauth_cred_t a_cred;
    772 	} */ *ap = v;
    773 	struct timespec ts;
    774 	struct vnode *vp = ap->a_vp;
    775 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    776 	int error;
    777 
    778 	ptyfs->ptyfs_flag |= PTYFS_ACCESS;
    779 	/* hardclock() resolution is good enough for ptyfs */
    780 	getnanotime(&ts);
    781 	(void)ptyfs_update(vp, &ts, &ts, 0);
    782 
    783 	switch (ptyfs->ptyfs_type) {
    784 	case PTYFSpts:
    785 	case PTYFSptc:
    786 		VOP_UNLOCK(vp, 0);
    787 		error = cdev_read(vp->v_rdev, ap->a_uio, ap->a_ioflag);
    788 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
    789 		return error;
    790 	default:
    791 		return EOPNOTSUPP;
    792 	}
    793 }
    794 
    795 int
    796 ptyfs_write(void *v)
    797 {
    798 	struct vop_write_args /* {
    799 		struct vnode *a_vp;
    800 		struct uio *a_uio;
    801 		int  a_ioflag;
    802 		kauth_cred_t a_cred;
    803 	} */ *ap = v;
    804 	struct timespec ts;
    805 	struct vnode *vp = ap->a_vp;
    806 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    807 	int error;
    808 
    809 	ptyfs->ptyfs_flag |= PTYFS_MODIFY;
    810 	getnanotime(&ts);
    811 	(void)ptyfs_update(vp, &ts, &ts, 0);
    812 
    813 	switch (ptyfs->ptyfs_type) {
    814 	case PTYFSpts:
    815 	case PTYFSptc:
    816 		VOP_UNLOCK(vp, 0);
    817 		error = cdev_write(vp->v_rdev, ap->a_uio, ap->a_ioflag);
    818 		vn_lock(vp, LK_RETRY|LK_EXCLUSIVE);
    819 		return error;
    820 	default:
    821 		return EOPNOTSUPP;
    822 	}
    823 }
    824 
    825 int
    826 ptyfs_ioctl(void *v)
    827 {
    828 	struct vop_ioctl_args /* {
    829 		struct vnode *a_vp;
    830 		u_long a_command;
    831 		void *a_data;
    832 		int  a_fflag;
    833 		kauth_cred_t a_cred;
    834 	} */ *ap = v;
    835 	struct vnode *vp = ap->a_vp;
    836 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    837 
    838 	switch (ptyfs->ptyfs_type) {
    839 	case PTYFSpts:
    840 	case PTYFSptc:
    841 		return cdev_ioctl(vp->v_rdev, ap->a_command,
    842 		    ap->a_data, ap->a_fflag, curlwp);
    843 	default:
    844 		return EOPNOTSUPP;
    845 	}
    846 }
    847 
    848 int
    849 ptyfs_poll(void *v)
    850 {
    851 	struct vop_poll_args /* {
    852 		struct vnode *a_vp;
    853 		int a_events;
    854 	} */ *ap = v;
    855 	struct vnode *vp = ap->a_vp;
    856 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    857 
    858 	switch (ptyfs->ptyfs_type) {
    859 	case PTYFSpts:
    860 	case PTYFSptc:
    861 		return cdev_poll(vp->v_rdev, ap->a_events, curlwp);
    862 	default:
    863 		return genfs_poll(v);
    864 	}
    865 }
    866 
    867 int
    868 ptyfs_kqfilter(void *v)
    869 {
    870 	struct vop_kqfilter_args /* {
    871 		struct vnode *a_vp;
    872 		struct knote *a_kn;
    873 	} */ *ap = v;
    874 	struct vnode *vp = ap->a_vp;
    875 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    876 
    877 	switch (ptyfs->ptyfs_type) {
    878 	case PTYFSpts:
    879 	case PTYFSptc:
    880 		return cdev_kqfilter(vp->v_rdev, ap->a_kn);
    881 	default:
    882 		return genfs_kqfilter(v);
    883 	}
    884 }
    885 
    886 static int
    887 ptyfs_update(struct vnode *vp, const struct timespec *acc,
    888     const struct timespec *mod, int flags)
    889 {
    890 	struct ptyfsnode *ptyfs = VTOPTYFS(vp);
    891 
    892 	if (vp->v_mount->mnt_flag & MNT_RDONLY)
    893 		return 0;
    894 
    895 	PTYFS_ITIMES(ptyfs, acc, mod, NULL);
    896 	return 0;
    897 }
    898 
    899 void
    900 ptyfs_itimes(struct ptyfsnode *ptyfs, const struct timespec *acc,
    901     const struct timespec *mod, const struct timespec *cre)
    902 {
    903 	struct timespec now;
    904 
    905 	KASSERT(ptyfs->ptyfs_flag & (PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY));
    906 
    907 	getnanotime(&now);
    908 	if (ptyfs->ptyfs_flag & PTYFS_ACCESS) {
    909 		if (acc == NULL)
    910 			acc = &now;
    911 		ptyfs->ptyfs_atime = *acc;
    912 	}
    913 	if (ptyfs->ptyfs_flag & PTYFS_MODIFY) {
    914 		if (mod == NULL)
    915 			mod = &now;
    916 		ptyfs->ptyfs_mtime = *mod;
    917 	}
    918 	if (ptyfs->ptyfs_flag & PTYFS_CHANGE) {
    919 		if (cre == NULL)
    920 			cre = &now;
    921 		ptyfs->ptyfs_ctime = *cre;
    922 	}
    923 	ptyfs->ptyfs_flag &= ~(PTYFS_ACCESS|PTYFS_CHANGE|PTYFS_MODIFY);
    924 }
    925 
    926 /*
    927  * convert decimal ascii to int
    928  */
    929 static int
    930 atoi(const char *b, size_t len)
    931 {
    932 	int p = 0;
    933 
    934 	while (len--) {
    935 		char c = *b++;
    936 		if (c < '0' || c > '9')
    937 			return -1;
    938 		p = 10 * p + (c - '0');
    939 	}
    940 
    941 	return p;
    942 }
    943