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fdesc_vnops.c revision 1.102.4.5
      1 /*	$NetBSD: fdesc_vnops.c,v 1.102.4.5 2010/03/11 15:04:22 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software donated 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  *	@(#)fdesc_vnops.c	8.17 (Berkeley) 5/22/95
     35  *
     36  * #Id: fdesc_vnops.c,v 1.12 1993/04/06 16:17:17 jsp Exp #
     37  */
     38 
     39 /*
     40  * /dev/fd Filesystem
     41  */
     42 
     43 #include <sys/cdefs.h>
     44 __KERNEL_RCSID(0, "$NetBSD: fdesc_vnops.c,v 1.102.4.5 2010/03/11 15:04:22 yamt Exp $");
     45 
     46 #include <sys/param.h>
     47 #include <sys/systm.h>
     48 #include <sys/time.h>
     49 #include <sys/proc.h>
     50 #include <sys/kernel.h>	/* boottime */
     51 #include <sys/resourcevar.h>
     52 #include <sys/socketvar.h>
     53 #include <sys/filedesc.h>
     54 #include <sys/vnode.h>
     55 #include <sys/malloc.h>
     56 #include <sys/conf.h>
     57 #include <sys/file.h>
     58 #include <sys/stat.h>
     59 #include <sys/mount.h>
     60 #include <sys/namei.h>
     61 #include <sys/buf.h>
     62 #include <sys/dirent.h>
     63 #include <sys/tty.h>
     64 #include <sys/kauth.h>
     65 #include <sys/atomic.h>
     66 
     67 #include <miscfs/fdesc/fdesc.h>
     68 #include <miscfs/genfs/genfs.h>
     69 
     70 #define cttyvp(p) ((p)->p_lflag & PL_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
     71 
     72 #define FDL_WANT	0x01
     73 #define FDL_LOCKED	0x02
     74 static int fdcache_lock;
     75 
     76 dev_t devctty;
     77 
     78 #if (FD_STDIN != FD_STDOUT-1) || (FD_STDOUT != FD_STDERR-1)
     79 FD_STDIN, FD_STDOUT, FD_STDERR must be a sequence n, n+1, n+2
     80 #endif
     81 
     82 #define	NFDCACHE 4
     83 
     84 #define FD_NHASH(ix) \
     85 	(&fdhashtbl[(ix) & fdhash])
     86 LIST_HEAD(fdhashhead, fdescnode) *fdhashtbl;
     87 u_long fdhash;
     88 
     89 int	fdesc_lookup(void *);
     90 #define	fdesc_create	genfs_eopnotsupp
     91 #define	fdesc_mknod	genfs_eopnotsupp
     92 int	fdesc_open(void *);
     93 #define	fdesc_close	genfs_nullop
     94 #define	fdesc_access	genfs_nullop
     95 int	fdesc_getattr(void *);
     96 int	fdesc_setattr(void *);
     97 int	fdesc_read(void *);
     98 int	fdesc_write(void *);
     99 int	fdesc_ioctl(void *);
    100 int	fdesc_poll(void *);
    101 int	fdesc_kqfilter(void *);
    102 #define	fdesc_mmap	genfs_eopnotsupp
    103 #define	fdesc_fcntl	genfs_fcntl
    104 #define	fdesc_fsync	genfs_nullop
    105 #define	fdesc_seek	genfs_seek
    106 #define	fdesc_remove	genfs_eopnotsupp
    107 int	fdesc_link(void *);
    108 #define	fdesc_rename	genfs_eopnotsupp
    109 #define	fdesc_mkdir	genfs_eopnotsupp
    110 #define	fdesc_rmdir	genfs_eopnotsupp
    111 int	fdesc_symlink(void *);
    112 int	fdesc_readdir(void *);
    113 int	fdesc_readlink(void *);
    114 #define	fdesc_abortop	genfs_abortop
    115 int	fdesc_inactive(void *);
    116 int	fdesc_reclaim(void *);
    117 #define	fdesc_lock	genfs_lock
    118 #define	fdesc_unlock	genfs_unlock
    119 #define	fdesc_bmap	genfs_badop
    120 #define	fdesc_strategy	genfs_badop
    121 int	fdesc_print(void *);
    122 int	fdesc_pathconf(void *);
    123 #define	fdesc_islocked	genfs_islocked
    124 #define	fdesc_advlock	genfs_einval
    125 #define	fdesc_bwrite	genfs_eopnotsupp
    126 #define fdesc_revoke	genfs_revoke
    127 #define fdesc_putpages	genfs_null_putpages
    128 
    129 static int fdesc_attr(int, struct vattr *, kauth_cred_t);
    130 
    131 int (**fdesc_vnodeop_p)(void *);
    132 const struct vnodeopv_entry_desc fdesc_vnodeop_entries[] = {
    133 	{ &vop_default_desc, vn_default_error },
    134 	{ &vop_lookup_desc, fdesc_lookup },		/* lookup */
    135 	{ &vop_create_desc, fdesc_create },		/* create */
    136 	{ &vop_mknod_desc, fdesc_mknod },		/* mknod */
    137 	{ &vop_open_desc, fdesc_open },			/* open */
    138 	{ &vop_close_desc, fdesc_close },		/* close */
    139 	{ &vop_access_desc, fdesc_access },		/* access */
    140 	{ &vop_getattr_desc, fdesc_getattr },		/* getattr */
    141 	{ &vop_setattr_desc, fdesc_setattr },		/* setattr */
    142 	{ &vop_read_desc, fdesc_read },			/* read */
    143 	{ &vop_write_desc, fdesc_write },		/* write */
    144 	{ &vop_ioctl_desc, fdesc_ioctl },		/* ioctl */
    145 	{ &vop_fcntl_desc, fdesc_fcntl },		/* fcntl */
    146 	{ &vop_poll_desc, fdesc_poll },			/* poll */
    147 	{ &vop_kqfilter_desc, fdesc_kqfilter },		/* kqfilter */
    148 	{ &vop_revoke_desc, fdesc_revoke },		/* revoke */
    149 	{ &vop_mmap_desc, fdesc_mmap },			/* mmap */
    150 	{ &vop_fsync_desc, fdesc_fsync },		/* fsync */
    151 	{ &vop_seek_desc, fdesc_seek },			/* seek */
    152 	{ &vop_remove_desc, fdesc_remove },		/* remove */
    153 	{ &vop_link_desc, fdesc_link },			/* link */
    154 	{ &vop_rename_desc, fdesc_rename },		/* rename */
    155 	{ &vop_mkdir_desc, fdesc_mkdir },		/* mkdir */
    156 	{ &vop_rmdir_desc, fdesc_rmdir },		/* rmdir */
    157 	{ &vop_symlink_desc, fdesc_symlink },		/* symlink */
    158 	{ &vop_readdir_desc, fdesc_readdir },		/* readdir */
    159 	{ &vop_readlink_desc, fdesc_readlink },		/* readlink */
    160 	{ &vop_abortop_desc, fdesc_abortop },		/* abortop */
    161 	{ &vop_inactive_desc, fdesc_inactive },		/* inactive */
    162 	{ &vop_reclaim_desc, fdesc_reclaim },		/* reclaim */
    163 	{ &vop_lock_desc, fdesc_lock },			/* lock */
    164 	{ &vop_unlock_desc, fdesc_unlock },		/* unlock */
    165 	{ &vop_bmap_desc, fdesc_bmap },			/* bmap */
    166 	{ &vop_strategy_desc, fdesc_strategy },		/* strategy */
    167 	{ &vop_print_desc, fdesc_print },		/* print */
    168 	{ &vop_islocked_desc, fdesc_islocked },		/* islocked */
    169 	{ &vop_pathconf_desc, fdesc_pathconf },		/* pathconf */
    170 	{ &vop_advlock_desc, fdesc_advlock },		/* advlock */
    171 	{ &vop_bwrite_desc, fdesc_bwrite },		/* bwrite */
    172 	{ &vop_putpages_desc, fdesc_putpages },		/* putpages */
    173 	{ NULL, NULL }
    174 };
    175 
    176 const struct vnodeopv_desc fdesc_vnodeop_opv_desc =
    177 	{ &fdesc_vnodeop_p, fdesc_vnodeop_entries };
    178 
    179 /*
    180  * Initialise cache headers
    181  */
    182 void
    183 fdesc_init(void)
    184 {
    185 	int cttymajor;
    186 
    187 	/* locate the major number */
    188 	cttymajor = devsw_name2chr("ctty", NULL, 0);
    189 	devctty = makedev(cttymajor, 0);
    190 	fdhashtbl = hashinit(NFDCACHE, HASH_LIST, true, &fdhash);
    191 }
    192 
    193 /*
    194  * Free hash table.
    195  */
    196 void
    197 fdesc_done(void)
    198 {
    199 	hashdone(fdhashtbl, HASH_LIST, fdhash);
    200 }
    201 
    202 /*
    203  * Return a locked vnode of the correct type.
    204  */
    205 int
    206 fdesc_allocvp(fdntype ftype, int ix, struct mount *mp, struct vnode **vpp)
    207 {
    208 	struct fdhashhead *fc;
    209 	struct fdescnode *fd;
    210 	int error = 0;
    211 
    212 	fc = FD_NHASH(ix);
    213 loop:
    214 	for (fd = fc->lh_first; fd != 0; fd = fd->fd_hash.le_next) {
    215 		if (fd->fd_ix == ix && fd->fd_vnode->v_mount == mp) {
    216 			if (vget(fd->fd_vnode, LK_EXCLUSIVE))
    217 				goto loop;
    218 			*vpp = fd->fd_vnode;
    219 			return (error);
    220 		}
    221 	}
    222 
    223 	/*
    224 	 * otherwise lock the array while we call getnewvnode
    225 	 * since that can block.
    226 	 */
    227 	if (fdcache_lock & FDL_LOCKED) {
    228 		fdcache_lock |= FDL_WANT;
    229 		(void) tsleep(&fdcache_lock, PINOD, "fdcache", 0);
    230 		goto loop;
    231 	}
    232 	fdcache_lock |= FDL_LOCKED;
    233 
    234 	error = getnewvnode(VT_FDESC, mp, fdesc_vnodeop_p, vpp);
    235 	if (error)
    236 		goto out;
    237 	fd = malloc(sizeof(struct fdescnode), M_TEMP, M_WAITOK);
    238 	(*vpp)->v_data = fd;
    239 	fd->fd_vnode = *vpp;
    240 	fd->fd_type = ftype;
    241 	fd->fd_fd = -1;
    242 	fd->fd_link = 0;
    243 	fd->fd_ix = ix;
    244 	uvm_vnp_setsize(*vpp, 0);
    245 	VOP_LOCK(*vpp, LK_EXCLUSIVE);
    246 	LIST_INSERT_HEAD(fc, fd, fd_hash);
    247 
    248 out:;
    249 	fdcache_lock &= ~FDL_LOCKED;
    250 
    251 	if (fdcache_lock & FDL_WANT) {
    252 		fdcache_lock &= ~FDL_WANT;
    253 		wakeup(&fdcache_lock);
    254 	}
    255 
    256 	return (error);
    257 }
    258 
    259 /*
    260  * vp is the current namei directory
    261  * ndp is the name to locate in that directory...
    262  */
    263 int
    264 fdesc_lookup(void *v)
    265 {
    266 	struct vop_lookup_args /* {
    267 		struct vnode * a_dvp;
    268 		struct vnode ** a_vpp;
    269 		struct componentname * a_cnp;
    270 	} */ *ap = v;
    271 	struct vnode **vpp = ap->a_vpp;
    272 	struct vnode *dvp = ap->a_dvp;
    273 	struct componentname *cnp = ap->a_cnp;
    274 	struct lwp *l = curlwp;
    275 	const char *pname = cnp->cn_nameptr;
    276 	struct proc *p = l->l_proc;
    277 	unsigned fd = 0;
    278 	int error;
    279 	struct vnode *fvp;
    280 	const char *ln;
    281 	fdtab_t *dt;
    282 
    283 	dt = curlwp->l_fd->fd_dt;
    284 
    285 	if (cnp->cn_namelen == 1 && *pname == '.') {
    286 		*vpp = dvp;
    287 		vref(dvp);
    288 		return (0);
    289 	}
    290 
    291 	switch (VTOFDESC(dvp)->fd_type) {
    292 	default:
    293 	case Flink:
    294 	case Fdesc:
    295 	case Fctty:
    296 		error = ENOTDIR;
    297 		goto bad;
    298 
    299 	case Froot:
    300 		if (cnp->cn_namelen == 2 && memcmp(pname, "fd", 2) == 0) {
    301 			error = fdesc_allocvp(Fdevfd, FD_DEVFD, dvp->v_mount, &fvp);
    302 			if (error)
    303 				goto bad;
    304 			*vpp = fvp;
    305 			fvp->v_type = VDIR;
    306 			goto good;
    307 		}
    308 
    309 		if (cnp->cn_namelen == 3 && memcmp(pname, "tty", 3) == 0) {
    310 			struct vnode *ttyvp = cttyvp(p);
    311 			if (ttyvp == NULL) {
    312 				error = ENXIO;
    313 				goto bad;
    314 			}
    315 			error = fdesc_allocvp(Fctty, FD_CTTY, dvp->v_mount, &fvp);
    316 			if (error)
    317 				goto bad;
    318 			*vpp = fvp;
    319 			fvp->v_type = VCHR;
    320 			goto good;
    321 		}
    322 
    323 		ln = 0;
    324 		switch (cnp->cn_namelen) {
    325 		case 5:
    326 			if (memcmp(pname, "stdin", 5) == 0) {
    327 				ln = "fd/0";
    328 				fd = FD_STDIN;
    329 			}
    330 			break;
    331 		case 6:
    332 			if (memcmp(pname, "stdout", 6) == 0) {
    333 				ln = "fd/1";
    334 				fd = FD_STDOUT;
    335 			} else
    336 			if (memcmp(pname, "stderr", 6) == 0) {
    337 				ln = "fd/2";
    338 				fd = FD_STDERR;
    339 			}
    340 			break;
    341 		}
    342 
    343 		if (ln) {
    344 			error = fdesc_allocvp(Flink, fd, dvp->v_mount, &fvp);
    345 			if (error)
    346 				goto bad;
    347 			/* XXXUNCONST */
    348 			VTOFDESC(fvp)->fd_link = __UNCONST(ln);
    349 			*vpp = fvp;
    350 			fvp->v_type = VLNK;
    351 			goto good;
    352 		} else {
    353 			error = ENOENT;
    354 			goto bad;
    355 		}
    356 
    357 		/* FALL THROUGH */
    358 
    359 	case Fdevfd:
    360 		if (cnp->cn_namelen == 2 && memcmp(pname, "..", 2) == 0) {
    361 			VOP_UNLOCK(dvp, 0);
    362 			error = fdesc_root(dvp->v_mount, vpp);
    363 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
    364 			if (error)
    365 				goto bad;
    366 			return (error);
    367 		}
    368 
    369 		fd = 0;
    370 		while (*pname >= '0' && *pname <= '9') {
    371 			fd = 10 * fd + *pname++ - '0';
    372 			if (fd >= dt->dt_nfiles)
    373 				break;
    374 		}
    375 
    376 		if (*pname != '\0') {
    377 			error = ENOENT;
    378 			goto bad;
    379 		}
    380 
    381 		if (fd >= dt->dt_nfiles || dt->dt_ff[fd] == NULL ||
    382 		    dt->dt_ff[fd]->ff_file == NULL) {
    383 			error = EBADF;
    384 			goto bad;
    385 		}
    386 
    387 		error = fdesc_allocvp(Fdesc, FD_DESC+fd, dvp->v_mount, &fvp);
    388 		if (error)
    389 			goto bad;
    390 		VTOFDESC(fvp)->fd_fd = fd;
    391 		*vpp = fvp;
    392 		goto good;
    393 	}
    394 
    395 bad:
    396 	*vpp = NULL;
    397 	return (error);
    398 
    399 good:
    400 	return (0);
    401 }
    402 
    403 int
    404 fdesc_open(void *v)
    405 {
    406 	struct vop_open_args /* {
    407 		struct vnode *a_vp;
    408 		int  a_mode;
    409 		kauth_cred_t a_cred;
    410 	} */ *ap = v;
    411 	struct vnode *vp = ap->a_vp;
    412 
    413 	switch (VTOFDESC(vp)->fd_type) {
    414 	case Fdesc:
    415 		/*
    416 		 * XXX Kludge: set dupfd to contain the value of the
    417 		 * the file descriptor being sought for duplication. The error
    418 		 * return ensures that the vnode for this device will be
    419 		 * released by vn_open. Open will detect this special error and
    420 		 * take the actions in dupfdopen.  Other callers of vn_open or
    421 		 * VOP_OPEN will simply report the error.
    422 		 */
    423 		curlwp->l_dupfd = VTOFDESC(vp)->fd_fd;	/* XXX */
    424 		return EDUPFD;
    425 
    426 	case Fctty:
    427 		return cdev_open(devctty, ap->a_mode, 0, curlwp);
    428 	case Froot:
    429 	case Fdevfd:
    430 	case Flink:
    431 		break;
    432 	}
    433 
    434 	return (0);
    435 }
    436 
    437 static int
    438 fdesc_attr(int fd, struct vattr *vap, kauth_cred_t cred)
    439 {
    440 	file_t *fp;
    441 	struct stat stb;
    442 	int error;
    443 
    444 	if ((fp = fd_getfile(fd)) == NULL)
    445 		return (EBADF);
    446 
    447 	switch (fp->f_type) {
    448 	case DTYPE_VNODE:
    449 		error = VOP_GETATTR((struct vnode *) fp->f_data, vap, cred);
    450 		if (error == 0 && vap->va_type == VDIR) {
    451 			/*
    452 			 * directories can cause loops in the namespace,
    453 			 * so turn off the 'x' bits to avoid trouble.
    454 			 */
    455 			vap->va_mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
    456 		}
    457 		break;
    458 
    459 	default:
    460 		memset(&stb, 0, sizeof(stb));
    461 		error = (*fp->f_ops->fo_stat)(fp, &stb);
    462 		if (error)
    463 			break;
    464 
    465 		vattr_null(vap);
    466 		switch(fp->f_type) {
    467 		case DTYPE_SOCKET:
    468 			vap->va_type = VSOCK;
    469 			break;
    470 		case DTYPE_PIPE:
    471 			vap->va_type = VFIFO;
    472 			break;
    473 		default:
    474 			/* use VNON perhaps? */
    475 			vap->va_type = VBAD;
    476 			break;
    477 		}
    478 		vap->va_mode = stb.st_mode;
    479 		vap->va_nlink = stb.st_nlink;
    480 		vap->va_uid = stb.st_uid;
    481 		vap->va_gid = stb.st_gid;
    482 		vap->va_fsid = stb.st_dev;
    483 		vap->va_fileid = stb.st_ino;
    484 		vap->va_size = stb.st_size;
    485 		vap->va_blocksize = stb.st_blksize;
    486 		vap->va_atime = stb.st_atimespec;
    487 		vap->va_mtime = stb.st_mtimespec;
    488 		vap->va_ctime = stb.st_ctimespec;
    489 		vap->va_gen = stb.st_gen;
    490 		vap->va_flags = stb.st_flags;
    491 		vap->va_rdev = stb.st_rdev;
    492 		vap->va_bytes = stb.st_blocks * stb.st_blksize;
    493 		break;
    494 	}
    495 
    496 	fd_putfile(fd);
    497 	return (error);
    498 }
    499 
    500 int
    501 fdesc_getattr(void *v)
    502 {
    503 	struct vop_getattr_args /* {
    504 		struct vnode *a_vp;
    505 		struct vattr *a_vap;
    506 		kauth_cred_t a_cred;
    507 		struct lwp *a_l;
    508 	} */ *ap = v;
    509 	struct vnode *vp = ap->a_vp;
    510 	struct vattr *vap = ap->a_vap;
    511 	unsigned fd;
    512 	int error = 0;
    513 
    514 	switch (VTOFDESC(vp)->fd_type) {
    515 	case Froot:
    516 	case Fdevfd:
    517 	case Flink:
    518 	case Fctty:
    519 		vattr_null(vap);
    520 		vap->va_fileid = VTOFDESC(vp)->fd_ix;
    521 
    522 #define R_ALL (S_IRUSR|S_IRGRP|S_IROTH)
    523 #define W_ALL (S_IWUSR|S_IWGRP|S_IWOTH)
    524 #define X_ALL (S_IXUSR|S_IXGRP|S_IXOTH)
    525 
    526 		switch (VTOFDESC(vp)->fd_type) {
    527 		case Flink:
    528 			vap->va_mode = R_ALL|X_ALL;
    529 			vap->va_type = VLNK;
    530 			vap->va_rdev = 0;
    531 			vap->va_nlink = 1;
    532 			vap->va_size = strlen(VTOFDESC(vp)->fd_link);
    533 			break;
    534 
    535 		case Fctty:
    536 			vap->va_mode = R_ALL|W_ALL;
    537 			vap->va_type = VCHR;
    538 			vap->va_rdev = devctty;
    539 			vap->va_nlink = 1;
    540 			vap->va_size = 0;
    541 			break;
    542 
    543 		default:
    544 			vap->va_mode = R_ALL|X_ALL;
    545 			vap->va_type = VDIR;
    546 			vap->va_rdev = 0;
    547 			vap->va_nlink = 2;
    548 			vap->va_size = DEV_BSIZE;
    549 			break;
    550 		}
    551 		vap->va_uid = 0;
    552 		vap->va_gid = 0;
    553 		vap->va_fsid = vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
    554 		vap->va_blocksize = DEV_BSIZE;
    555 		vap->va_atime.tv_sec = boottime.tv_sec;
    556 		vap->va_atime.tv_nsec = 0;
    557 		vap->va_mtime = vap->va_atime;
    558 		vap->va_ctime = vap->va_mtime;
    559 		vap->va_gen = 0;
    560 		vap->va_flags = 0;
    561 		vap->va_bytes = 0;
    562 		break;
    563 
    564 	case Fdesc:
    565 		fd = VTOFDESC(vp)->fd_fd;
    566 		error = fdesc_attr(fd, vap, ap->a_cred);
    567 		break;
    568 
    569 	default:
    570 		panic("fdesc_getattr");
    571 		break;
    572 	}
    573 
    574 	if (error == 0)
    575 		vp->v_type = vap->va_type;
    576 
    577 	return (error);
    578 }
    579 
    580 int
    581 fdesc_setattr(void *v)
    582 {
    583 	struct vop_setattr_args /* {
    584 		struct vnode *a_vp;
    585 		struct vattr *a_vap;
    586 		kauth_cred_t a_cred;
    587 	} */ *ap = v;
    588 	file_t *fp;
    589 	unsigned fd;
    590 
    591 	/*
    592 	 * Can't mess with the root vnode
    593 	 */
    594 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    595 	case Fdesc:
    596 		break;
    597 
    598 	case Fctty:
    599 		return (0);
    600 
    601 	default:
    602 		return (EACCES);
    603 	}
    604 
    605 	fd = VTOFDESC(ap->a_vp)->fd_fd;
    606 	if ((fp = fd_getfile(fd)) == NULL)
    607 		return (EBADF);
    608 
    609 	/*
    610 	 * XXX: Can't reasonably set the attr's on any types currently.
    611 	 *      On vnode's this will cause truncation and socket/pipes make
    612 	 *      no sense.
    613 	 */
    614 	fd_putfile(fd);
    615 	return (0);
    616 }
    617 
    618 
    619 struct fdesc_target {
    620 	ino_t ft_fileno;
    621 	u_char ft_type;
    622 	u_char ft_namlen;
    623 	const char *ft_name;
    624 } fdesc_targets[] = {
    625 #define N(s) sizeof(s)-1, s
    626 	{ FD_DEVFD,  DT_DIR,     N("fd")     },
    627 	{ FD_STDIN,  DT_LNK,     N("stdin")  },
    628 	{ FD_STDOUT, DT_LNK,     N("stdout") },
    629 	{ FD_STDERR, DT_LNK,     N("stderr") },
    630 	{ FD_CTTY,   DT_UNKNOWN, N("tty")    },
    631 #undef N
    632 #define UIO_MX _DIRENT_RECLEN((struct dirent *)NULL, sizeof("stderr") - 1)
    633 };
    634 static int nfdesc_targets = sizeof(fdesc_targets) / sizeof(fdesc_targets[0]);
    635 
    636 int
    637 fdesc_readdir(void *v)
    638 {
    639 	struct vop_readdir_args /* {
    640 		struct vnode *a_vp;
    641 		struct uio *a_uio;
    642 		kauth_cred_t a_cred;
    643 		int *a_eofflag;
    644 		off_t **a_cookies;
    645 		int *a_ncookies;
    646 	} */ *ap = v;
    647 	struct uio *uio = ap->a_uio;
    648 	struct dirent d;
    649 	off_t i;
    650 	int j;
    651 	int error;
    652 	off_t *cookies = NULL;
    653 	int ncookies;
    654 	fdtab_t *dt;
    655 
    656 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    657 	case Fctty:
    658 		return 0;
    659 
    660 	case Fdesc:
    661 		return ENOTDIR;
    662 
    663 	default:
    664 		break;
    665 	}
    666 
    667 	dt = curlwp->l_fd->fd_dt;
    668 
    669 	if (uio->uio_resid < UIO_MX)
    670 		return EINVAL;
    671 	if (uio->uio_offset < 0)
    672 		return EINVAL;
    673 
    674 	error = 0;
    675 	i = uio->uio_offset;
    676 	(void)memset(&d, 0, UIO_MX);
    677 	d.d_reclen = UIO_MX;
    678 	if (ap->a_ncookies)
    679 		ncookies = uio->uio_resid / UIO_MX;
    680 	else
    681 		ncookies = 0;
    682 
    683 	if (VTOFDESC(ap->a_vp)->fd_type == Froot) {
    684 		struct fdesc_target *ft;
    685 
    686 		if (i >= nfdesc_targets)
    687 			return 0;
    688 
    689 		if (ap->a_ncookies) {
    690 			ncookies = min(ncookies, (nfdesc_targets - i));
    691 			cookies = malloc(ncookies * sizeof(off_t),
    692 			    M_TEMP, M_WAITOK);
    693 			*ap->a_cookies = cookies;
    694 			*ap->a_ncookies = ncookies;
    695 		}
    696 
    697 		for (ft = &fdesc_targets[i]; uio->uio_resid >= UIO_MX &&
    698 		    i < nfdesc_targets; ft++, i++) {
    699 			switch (ft->ft_fileno) {
    700 			case FD_CTTY:
    701 				if (cttyvp(curproc) == NULL)
    702 					continue;
    703 				break;
    704 
    705 			case FD_STDIN:
    706 			case FD_STDOUT:
    707 			case FD_STDERR:
    708 				if ((ft->ft_fileno - FD_STDIN) >=
    709 				    dt->dt_nfiles)
    710 					continue;
    711 				if (dt->dt_ff[ft->ft_fileno - FD_STDIN]
    712 				    == NULL || dt->dt_ff[ft->ft_fileno -
    713 				    FD_STDIN]->ff_file == NULL)
    714 					continue;
    715 				break;
    716 			}
    717 
    718 			d.d_fileno = ft->ft_fileno;
    719 			d.d_namlen = ft->ft_namlen;
    720 			(void)memcpy(d.d_name, ft->ft_name, ft->ft_namlen + 1);
    721 			d.d_type = ft->ft_type;
    722 
    723 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
    724 				break;
    725 			if (cookies)
    726 				*cookies++ = i + 1;
    727 		}
    728 	} else {
    729 		membar_consumer();
    730 		if (ap->a_ncookies) {
    731 			ncookies = min(ncookies, dt->dt_nfiles + 2);
    732 			cookies = malloc(ncookies * sizeof(off_t),
    733 			    M_TEMP, M_WAITOK);
    734 			*ap->a_cookies = cookies;
    735 			*ap->a_ncookies = ncookies;
    736 		}
    737 		for (; i - 2 < dt->dt_nfiles && uio->uio_resid >= UIO_MX; i++) {
    738 			switch (i) {
    739 			case 0:
    740 			case 1:
    741 				d.d_fileno = FD_ROOT;		/* XXX */
    742 				d.d_namlen = i + 1;
    743 				(void)memcpy(d.d_name, "..", d.d_namlen);
    744 				d.d_name[i + 1] = '\0';
    745 				d.d_type = DT_DIR;
    746 				break;
    747 
    748 			default:
    749 				j = (int)i - 2;
    750 				if (dt->dt_ff[j] == NULL ||
    751 				    dt->dt_ff[j]->ff_file == NULL)
    752 					continue;
    753 				d.d_fileno = j + FD_STDIN;
    754 				d.d_namlen = sprintf(d.d_name, "%d", j);
    755 				d.d_type = DT_UNKNOWN;
    756 				break;
    757 			}
    758 
    759 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
    760 				break;
    761 			if (cookies)
    762 				*cookies++ = i + 1;
    763 		}
    764 	}
    765 
    766 	if (ap->a_ncookies && error) {
    767 		free(*ap->a_cookies, M_TEMP);
    768 		*ap->a_ncookies = 0;
    769 		*ap->a_cookies = NULL;
    770 	}
    771 
    772 	uio->uio_offset = i;
    773 	return error;
    774 }
    775 
    776 int
    777 fdesc_readlink(void *v)
    778 {
    779 	struct vop_readlink_args /* {
    780 		struct vnode *a_vp;
    781 		struct uio *a_uio;
    782 		kauth_cred_t a_cred;
    783 	} */ *ap = v;
    784 	struct vnode *vp = ap->a_vp;
    785 	int error;
    786 
    787 	if (vp->v_type != VLNK)
    788 		return (EPERM);
    789 
    790 	if (VTOFDESC(vp)->fd_type == Flink) {
    791 		char *ln = VTOFDESC(vp)->fd_link;
    792 		error = uiomove(ln, strlen(ln), ap->a_uio);
    793 	} else {
    794 		error = EOPNOTSUPP;
    795 	}
    796 
    797 	return (error);
    798 }
    799 
    800 int
    801 fdesc_read(void *v)
    802 {
    803 	struct vop_read_args /* {
    804 		struct vnode *a_vp;
    805 		struct uio *a_uio;
    806 		int  a_ioflag;
    807 		kauth_cred_t a_cred;
    808 	} */ *ap = v;
    809 	int error = EOPNOTSUPP;
    810 	struct vnode *vp = ap->a_vp;
    811 
    812 	switch (VTOFDESC(vp)->fd_type) {
    813 	case Fctty:
    814 		VOP_UNLOCK(vp, 0);
    815 		error = cdev_read(devctty, ap->a_uio, ap->a_ioflag);
    816 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
    817 		break;
    818 
    819 	default:
    820 		error = EOPNOTSUPP;
    821 		break;
    822 	}
    823 
    824 	return (error);
    825 }
    826 
    827 int
    828 fdesc_write(void *v)
    829 {
    830 	struct vop_write_args /* {
    831 		struct vnode *a_vp;
    832 		struct uio *a_uio;
    833 		int  a_ioflag;
    834 		kauth_cred_t a_cred;
    835 	} */ *ap = v;
    836 	int error = EOPNOTSUPP;
    837 	struct vnode *vp = ap->a_vp;
    838 
    839 	switch (VTOFDESC(vp)->fd_type) {
    840 	case Fctty:
    841 		VOP_UNLOCK(vp, 0);
    842 		error = cdev_write(devctty, ap->a_uio, ap->a_ioflag);
    843 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
    844 		break;
    845 
    846 	default:
    847 		error = EOPNOTSUPP;
    848 		break;
    849 	}
    850 
    851 	return (error);
    852 }
    853 
    854 int
    855 fdesc_ioctl(void *v)
    856 {
    857 	struct vop_ioctl_args /* {
    858 		struct vnode *a_vp;
    859 		u_long a_command;
    860 		void *a_data;
    861 		int  a_fflag;
    862 		kauth_cred_t a_cred;
    863 	} */ *ap = v;
    864 	int error = EOPNOTSUPP;
    865 
    866 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    867 	case Fctty:
    868 		error = cdev_ioctl(devctty, ap->a_command, ap->a_data,
    869 		    ap->a_fflag, curlwp);
    870 		break;
    871 
    872 	default:
    873 		error = EOPNOTSUPP;
    874 		break;
    875 	}
    876 
    877 	return (error);
    878 }
    879 
    880 int
    881 fdesc_poll(void *v)
    882 {
    883 	struct vop_poll_args /* {
    884 		struct vnode *a_vp;
    885 		int a_events;
    886 	} */ *ap = v;
    887 	int revents;
    888 
    889 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    890 	case Fctty:
    891 		revents = cdev_poll(devctty, ap->a_events, curlwp);
    892 		break;
    893 
    894 	default:
    895 		revents = genfs_poll(v);
    896 		break;
    897 	}
    898 
    899 	return (revents);
    900 }
    901 
    902 int
    903 fdesc_kqfilter(void *v)
    904 {
    905 	struct vop_kqfilter_args /* {
    906 		struct vnode *a_vp;
    907 		struct knote *a_kn;
    908 	} */ *ap = v;
    909 	int error, fd;
    910 	file_t *fp;
    911 
    912 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    913 	case Fctty:
    914 		error = cdev_kqfilter(devctty, ap->a_kn);
    915 		break;
    916 
    917 	case Fdesc:
    918 		/* just invoke kqfilter for the underlying descriptor */
    919 		fd = VTOFDESC(ap->a_vp)->fd_fd;
    920 		if ((fp = fd_getfile(fd)) == NULL)
    921 			return (1);
    922 		error = (*fp->f_ops->fo_kqfilter)(fp, ap->a_kn);
    923 		fd_putfile(fd);
    924 		break;
    925 
    926 	default:
    927 		return (genfs_kqfilter(v));
    928 	}
    929 
    930 	return (error);
    931 }
    932 
    933 int
    934 fdesc_inactive(void *v)
    935 {
    936 	struct vop_inactive_args /* {
    937 		struct vnode *a_vp;
    938 	} */ *ap = v;
    939 	struct vnode *vp = ap->a_vp;
    940 
    941 	/*
    942 	 * Clear out the v_type field to avoid
    943 	 * nasty things happening in vgone().
    944 	 */
    945 	VOP_UNLOCK(vp, 0);
    946 	vp->v_type = VNON;
    947 	return (0);
    948 }
    949 
    950 int
    951 fdesc_reclaim(void *v)
    952 {
    953 	struct vop_reclaim_args /* {
    954 		struct vnode *a_vp;
    955 	} */ *ap = v;
    956 	struct vnode *vp = ap->a_vp;
    957 	struct fdescnode *fd = VTOFDESC(vp);
    958 
    959 	LIST_REMOVE(fd, fd_hash);
    960 	free(vp->v_data, M_TEMP);
    961 	vp->v_data = 0;
    962 
    963 	return (0);
    964 }
    965 
    966 /*
    967  * Return POSIX pathconf information applicable to special devices.
    968  */
    969 int
    970 fdesc_pathconf(void *v)
    971 {
    972 	struct vop_pathconf_args /* {
    973 		struct vnode *a_vp;
    974 		int a_name;
    975 		register_t *a_retval;
    976 	} */ *ap = v;
    977 
    978 	switch (ap->a_name) {
    979 	case _PC_LINK_MAX:
    980 		*ap->a_retval = LINK_MAX;
    981 		return (0);
    982 	case _PC_MAX_CANON:
    983 		*ap->a_retval = MAX_CANON;
    984 		return (0);
    985 	case _PC_MAX_INPUT:
    986 		*ap->a_retval = MAX_INPUT;
    987 		return (0);
    988 	case _PC_PIPE_BUF:
    989 		*ap->a_retval = PIPE_BUF;
    990 		return (0);
    991 	case _PC_CHOWN_RESTRICTED:
    992 		*ap->a_retval = 1;
    993 		return (0);
    994 	case _PC_VDISABLE:
    995 		*ap->a_retval = _POSIX_VDISABLE;
    996 		return (0);
    997 	case _PC_SYNC_IO:
    998 		*ap->a_retval = 1;
    999 		return (0);
   1000 	default:
   1001 		return (EINVAL);
   1002 	}
   1003 	/* NOTREACHED */
   1004 }
   1005 
   1006 /*
   1007  * Print out the contents of a /dev/fd vnode.
   1008  */
   1009 /* ARGSUSED */
   1010 int
   1011 fdesc_print(void *v)
   1012 {
   1013 	printf("tag VT_NON, fdesc vnode\n");
   1014 	return (0);
   1015 }
   1016 
   1017 int
   1018 fdesc_link(void *v)
   1019 {
   1020 	struct vop_link_args /* {
   1021 		struct vnode *a_dvp;
   1022 		struct vnode *a_vp;
   1023 		struct componentname *a_cnp;
   1024 	} */ *ap = v;
   1025 
   1026 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
   1027 	vput(ap->a_dvp);
   1028 	return (EROFS);
   1029 }
   1030 
   1031 int
   1032 fdesc_symlink(void *v)
   1033 {
   1034 	struct vop_symlink_args /* {
   1035 		struct vnode *a_dvp;
   1036 		struct vnode **a_vpp;
   1037 		struct componentname *a_cnp;
   1038 		struct vattr *a_vap;
   1039 		char *a_target;
   1040 	} */ *ap = v;
   1041 
   1042 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
   1043 	vput(ap->a_dvp);
   1044 	return (EROFS);
   1045 }
   1046