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fdesc_vnops.c revision 1.64.2.2
      1 /*	$NetBSD: fdesc_vnops.c,v 1.64.2.2 2001/09/08 03:29:22 thorpej 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. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  *
     38  *	@(#)fdesc_vnops.c	8.17 (Berkeley) 5/22/95
     39  *
     40  * #Id: fdesc_vnops.c,v 1.12 1993/04/06 16:17:17 jsp Exp #
     41  */
     42 
     43 /*
     44  * /dev/fd Filesystem
     45  */
     46 
     47 #include <sys/param.h>
     48 #include <sys/systm.h>
     49 #include <sys/types.h>
     50 #include <sys/time.h>
     51 #include <sys/proc.h>
     52 #include <sys/kernel.h>	/* boottime */
     53 #include <sys/resourcevar.h>
     54 #include <sys/socketvar.h>
     55 #include <sys/filedesc.h>
     56 #include <sys/vnode.h>
     57 #include <sys/malloc.h>
     58 #include <sys/conf.h>
     59 #include <sys/file.h>
     60 #include <sys/stat.h>
     61 #include <sys/mount.h>
     62 #include <sys/namei.h>
     63 #include <sys/buf.h>
     64 #include <sys/dirent.h>
     65 #include <sys/tty.h>
     66 
     67 #include <miscfs/fdesc/fdesc.h>
     68 #include <miscfs/genfs/genfs.h>
     69 
     70 #define cttyvp(p) ((p)->p_flag & P_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	__P((void *));
     90 #define	fdesc_create	genfs_eopnotsupp_rele
     91 #define	fdesc_mknod	genfs_eopnotsupp_rele
     92 int	fdesc_open	__P((void *));
     93 #define	fdesc_close	genfs_nullop
     94 #define	fdesc_access	genfs_nullop
     95 int	fdesc_getattr	__P((void *));
     96 int	fdesc_setattr	__P((void *));
     97 int	fdesc_read	__P((void *));
     98 int	fdesc_write	__P((void *));
     99 int	fdesc_ioctl	__P((void *));
    100 int	fdesc_poll	__P((void *));
    101 int	fdesc_kqfilter	__P((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_rele
    107 int	fdesc_link	__P((void *));
    108 #define	fdesc_rename	genfs_eopnotsupp_rele
    109 #define	fdesc_mkdir	genfs_eopnotsupp_rele
    110 #define	fdesc_rmdir	genfs_eopnotsupp_rele
    111 int	fdesc_symlink	__P((void *));
    112 int	fdesc_readdir	__P((void *));
    113 int	fdesc_readlink	__P((void *));
    114 #define	fdesc_abortop	genfs_abortop
    115 int	fdesc_inactive	__P((void *));
    116 int	fdesc_reclaim	__P((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	__P((void *));
    122 int	fdesc_pathconf	__P((void *));
    123 #define	fdesc_islocked	genfs_islocked
    124 #define	fdesc_advlock	genfs_einval
    125 #define	fdesc_blkatoff	genfs_eopnotsupp
    126 #define	fdesc_valloc	genfs_eopnotsupp
    127 #define	fdesc_vfree	genfs_nullop
    128 #define	fdesc_truncate	genfs_eopnotsupp
    129 #define	fdesc_update	genfs_nullop
    130 #define	fdesc_bwrite	genfs_eopnotsupp
    131 #define fdesc_revoke	genfs_revoke
    132 
    133 static int fdesc_attr __P((int, struct vattr *, struct ucred *, struct proc *));
    134 
    135 int (**fdesc_vnodeop_p) __P((void *));
    136 const struct vnodeopv_entry_desc fdesc_vnodeop_entries[] = {
    137 	{ &vop_default_desc, vn_default_error },
    138 	{ &vop_lookup_desc, fdesc_lookup },		/* lookup */
    139 	{ &vop_create_desc, fdesc_create },		/* create */
    140 	{ &vop_mknod_desc, fdesc_mknod },		/* mknod */
    141 	{ &vop_open_desc, fdesc_open },			/* open */
    142 	{ &vop_close_desc, fdesc_close },		/* close */
    143 	{ &vop_access_desc, fdesc_access },		/* access */
    144 	{ &vop_getattr_desc, fdesc_getattr },		/* getattr */
    145 	{ &vop_setattr_desc, fdesc_setattr },		/* setattr */
    146 	{ &vop_read_desc, fdesc_read },			/* read */
    147 	{ &vop_write_desc, fdesc_write },		/* write */
    148 	{ &vop_ioctl_desc, fdesc_ioctl },		/* ioctl */
    149 	{ &vop_fcntl_desc, fdesc_fcntl },		/* fcntl */
    150 	{ &vop_poll_desc, fdesc_poll },			/* poll */
    151 	{ &vop_kqfilter_desc, fdesc_kqfilter },		/* kqfilter */
    152 	{ &vop_revoke_desc, fdesc_revoke },		/* revoke */
    153 	{ &vop_mmap_desc, fdesc_mmap },			/* mmap */
    154 	{ &vop_fsync_desc, fdesc_fsync },		/* fsync */
    155 	{ &vop_seek_desc, fdesc_seek },			/* seek */
    156 	{ &vop_remove_desc, fdesc_remove },		/* remove */
    157 	{ &vop_link_desc, fdesc_link },			/* link */
    158 	{ &vop_rename_desc, fdesc_rename },		/* rename */
    159 	{ &vop_mkdir_desc, fdesc_mkdir },		/* mkdir */
    160 	{ &vop_rmdir_desc, fdesc_rmdir },		/* rmdir */
    161 	{ &vop_symlink_desc, fdesc_symlink },		/* symlink */
    162 	{ &vop_readdir_desc, fdesc_readdir },		/* readdir */
    163 	{ &vop_readlink_desc, fdesc_readlink },		/* readlink */
    164 	{ &vop_abortop_desc, fdesc_abortop },		/* abortop */
    165 	{ &vop_inactive_desc, fdesc_inactive },		/* inactive */
    166 	{ &vop_reclaim_desc, fdesc_reclaim },		/* reclaim */
    167 	{ &vop_lock_desc, fdesc_lock },			/* lock */
    168 	{ &vop_unlock_desc, fdesc_unlock },		/* unlock */
    169 	{ &vop_bmap_desc, fdesc_bmap },			/* bmap */
    170 	{ &vop_strategy_desc, fdesc_strategy },		/* strategy */
    171 	{ &vop_print_desc, fdesc_print },		/* print */
    172 	{ &vop_islocked_desc, fdesc_islocked },		/* islocked */
    173 	{ &vop_pathconf_desc, fdesc_pathconf },		/* pathconf */
    174 	{ &vop_advlock_desc, fdesc_advlock },		/* advlock */
    175 	{ &vop_blkatoff_desc, fdesc_blkatoff },		/* blkatoff */
    176 	{ &vop_valloc_desc, fdesc_valloc },		/* valloc */
    177 	{ &vop_vfree_desc, fdesc_vfree },		/* vfree */
    178 	{ &vop_truncate_desc, fdesc_truncate },		/* truncate */
    179 	{ &vop_update_desc, fdesc_update },		/* update */
    180 	{ &vop_bwrite_desc, fdesc_bwrite },		/* bwrite */
    181 	{ (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
    182 };
    183 
    184 const struct vnodeopv_desc fdesc_vnodeop_opv_desc =
    185 	{ &fdesc_vnodeop_p, fdesc_vnodeop_entries };
    186 
    187 /*
    188  * Initialise cache headers
    189  */
    190 void
    191 fdesc_init()
    192 {
    193 	int cttymajor;
    194 
    195 	/* locate the major number */
    196 	for (cttymajor = 0; cttymajor < nchrdev; cttymajor++)
    197 		if (cdevsw[cttymajor].d_open == cttyopen)
    198 			break;
    199 	devctty = makedev(cttymajor, 0);
    200 	fdhashtbl = hashinit(NFDCACHE, HASH_LIST, M_CACHE, M_NOWAIT, &fdhash);
    201 }
    202 
    203 /*
    204  * Free hash table.
    205  */
    206 void
    207 fdesc_done()
    208 {
    209 	hashdone(fdhashtbl, M_CACHE);
    210 }
    211 
    212 /*
    213  * Return a locked vnode of the correct type.
    214  */
    215 int
    216 fdesc_allocvp(ftype, ix, mp, vpp)
    217 	fdntype ftype;
    218 	int ix;
    219 	struct mount *mp;
    220 	struct vnode **vpp;
    221 {
    222 	struct fdhashhead *fc;
    223 	struct fdescnode *fd;
    224 	int error = 0;
    225 
    226 	fc = FD_NHASH(ix);
    227 loop:
    228 	for (fd = fc->lh_first; fd != 0; fd = fd->fd_hash.le_next) {
    229 		if (fd->fd_ix == ix && fd->fd_vnode->v_mount == mp) {
    230 			if (vget(fd->fd_vnode, LK_EXCLUSIVE))
    231 				goto loop;
    232 			*vpp = fd->fd_vnode;
    233 			return (error);
    234 		}
    235 	}
    236 
    237 	/*
    238 	 * otherwise lock the array while we call getnewvnode
    239 	 * since that can block.
    240 	 */
    241 	if (fdcache_lock & FDL_LOCKED) {
    242 		fdcache_lock |= FDL_WANT;
    243 		(void) tsleep(&fdcache_lock, PINOD, "fdcache", 0);
    244 		goto loop;
    245 	}
    246 	fdcache_lock |= FDL_LOCKED;
    247 
    248 	error = getnewvnode(VT_FDESC, mp, fdesc_vnodeop_p, vpp);
    249 	if (error)
    250 		goto out;
    251 	MALLOC(fd, void *, sizeof(struct fdescnode), M_TEMP, M_WAITOK);
    252 	(*vpp)->v_data = fd;
    253 	fd->fd_vnode = *vpp;
    254 	fd->fd_type = ftype;
    255 	fd->fd_fd = -1;
    256 	fd->fd_link = 0;
    257 	fd->fd_ix = ix;
    258 	VOP_LOCK(*vpp, LK_EXCLUSIVE);
    259 	LIST_INSERT_HEAD(fc, fd, fd_hash);
    260 
    261 out:;
    262 	fdcache_lock &= ~FDL_LOCKED;
    263 
    264 	if (fdcache_lock & FDL_WANT) {
    265 		fdcache_lock &= ~FDL_WANT;
    266 		wakeup((caddr_t) &fdcache_lock);
    267 	}
    268 
    269 	return (error);
    270 }
    271 
    272 /*
    273  * vp is the current namei directory
    274  * ndp is the name to locate in that directory...
    275  */
    276 int
    277 fdesc_lookup(v)
    278 	void *v;
    279 {
    280 	struct vop_lookup_args /* {
    281 		struct vnode * a_dvp;
    282 		struct vnode ** a_vpp;
    283 		struct componentname * a_cnp;
    284 	} */ *ap = v;
    285 	struct vnode **vpp = ap->a_vpp;
    286 	struct vnode *dvp = ap->a_dvp;
    287 	struct componentname *cnp = ap->a_cnp;
    288 	struct proc *p = cnp->cn_proc;
    289 	const char *pname = cnp->cn_nameptr;
    290 	int nfiles = p->p_fd->fd_nfiles;
    291 	unsigned fd = 0;
    292 	int error;
    293 	struct vnode *fvp;
    294 	char *ln;
    295 
    296 	if (cnp->cn_namelen == 1 && *pname == '.') {
    297 		*vpp = dvp;
    298 		VREF(dvp);
    299 		return (0);
    300 	}
    301 
    302 	switch (VTOFDESC(dvp)->fd_type) {
    303 	default:
    304 	case Flink:
    305 	case Fdesc:
    306 	case Fctty:
    307 		error = ENOTDIR;
    308 		goto bad;
    309 
    310 	case Froot:
    311 		if (cnp->cn_namelen == 2 && memcmp(pname, "fd", 2) == 0) {
    312 			error = fdesc_allocvp(Fdevfd, FD_DEVFD, dvp->v_mount, &fvp);
    313 			if (error)
    314 				goto bad;
    315 			*vpp = fvp;
    316 			fvp->v_type = VDIR;
    317 			goto good;
    318 		}
    319 
    320 		if (cnp->cn_namelen == 3 && memcmp(pname, "tty", 3) == 0) {
    321 			struct vnode *ttyvp = cttyvp(p);
    322 			if (ttyvp == NULL) {
    323 				error = ENXIO;
    324 				goto bad;
    325 			}
    326 			error = fdesc_allocvp(Fctty, FD_CTTY, dvp->v_mount, &fvp);
    327 			if (error)
    328 				goto bad;
    329 			*vpp = fvp;
    330 			fvp->v_type = VCHR;
    331 			goto good;
    332 		}
    333 
    334 		ln = 0;
    335 		switch (cnp->cn_namelen) {
    336 		case 5:
    337 			if (memcmp(pname, "stdin", 5) == 0) {
    338 				ln = "fd/0";
    339 				fd = FD_STDIN;
    340 			}
    341 			break;
    342 		case 6:
    343 			if (memcmp(pname, "stdout", 6) == 0) {
    344 				ln = "fd/1";
    345 				fd = FD_STDOUT;
    346 			} else
    347 			if (memcmp(pname, "stderr", 6) == 0) {
    348 				ln = "fd/2";
    349 				fd = FD_STDERR;
    350 			}
    351 			break;
    352 		}
    353 
    354 		if (ln) {
    355 			error = fdesc_allocvp(Flink, fd, dvp->v_mount, &fvp);
    356 			if (error)
    357 				goto bad;
    358 			VTOFDESC(fvp)->fd_link = ln;
    359 			*vpp = fvp;
    360 			fvp->v_type = VLNK;
    361 			goto good;
    362 		} else {
    363 			error = ENOENT;
    364 			goto bad;
    365 		}
    366 
    367 		/* FALL THROUGH */
    368 
    369 	case Fdevfd:
    370 		if (cnp->cn_namelen == 2 && memcmp(pname, "..", 2) == 0) {
    371 			VOP_UNLOCK(dvp, 0);
    372 			cnp->cn_flags |= PDIRUNLOCK;
    373 			error = fdesc_root(dvp->v_mount, vpp);
    374 			if (error)
    375 				goto bad;
    376 			/*
    377 			 * If we're at the last component and need the
    378 			 * parent locked, undo the unlock above.
    379 			 */
    380 			if (((~cnp->cn_flags & (ISLASTCN | LOCKPARENT)) == 0) &&
    381 				   ((error = vn_lock(dvp, LK_EXCLUSIVE)) == 0))
    382 				cnp->cn_flags &= ~PDIRUNLOCK;
    383 			return (error);
    384 		}
    385 
    386 		fd = 0;
    387 		while (*pname >= '0' && *pname <= '9') {
    388 			fd = 10 * fd + *pname++ - '0';
    389 			if (fd >= nfiles)
    390 				break;
    391 		}
    392 
    393 		if (*pname != '\0') {
    394 			error = ENOENT;
    395 			goto bad;
    396 		}
    397 
    398 		if (fd >= nfiles || p->p_fd->fd_ofiles[fd] == NULL ||
    399 		    FILE_IS_USABLE(p->p_fd->fd_ofiles[fd]) == 0) {
    400 			error = EBADF;
    401 			goto bad;
    402 		}
    403 
    404 		error = fdesc_allocvp(Fdesc, FD_DESC+fd, dvp->v_mount, &fvp);
    405 		if (error)
    406 			goto bad;
    407 		VTOFDESC(fvp)->fd_fd = fd;
    408 		*vpp = fvp;
    409 		goto good;
    410 	}
    411 
    412 bad:;
    413 	*vpp = NULL;
    414 	return (error);
    415 
    416 good:;
    417 	/*
    418 	 * As "." was special cased above, we now unlock the parent if we're
    419 	 * suppoed to. We're only supposed to not unlock if this is the
    420 	 * last component, and the caller requested LOCKPARENT. So if either
    421 	 * condition is false, unlock.
    422 	 */
    423 	if (((~cnp->cn_flags) & (ISLASTCN | LOCKPARENT)) != 0) {
    424 		VOP_UNLOCK(dvp, 0);
    425 		cnp->cn_flags |= PDIRUNLOCK;
    426 	}
    427 	return (0);
    428 }
    429 
    430 int
    431 fdesc_open(v)
    432 	void *v;
    433 {
    434 	struct vop_open_args /* {
    435 		struct vnode *a_vp;
    436 		int  a_mode;
    437 		struct ucred *a_cred;
    438 		struct proc *a_p;
    439 	} */ *ap = v;
    440 	struct vnode *vp = ap->a_vp;
    441 
    442 	switch (VTOFDESC(vp)->fd_type) {
    443 	case Fdesc:
    444 		/*
    445 		 * XXX Kludge: set p->p_dupfd to contain the value of the
    446 		 * the file descriptor being sought for duplication. The error
    447 		 * return ensures that the vnode for this device will be
    448 		 * released by vn_open. Open will detect this special error and
    449 		 * take the actions in dupfdopen.  Other callers of vn_open or
    450 		 * VOP_OPEN will simply report the error.
    451 		 */
    452 		ap->a_p->p_dupfd = VTOFDESC(vp)->fd_fd;	/* XXX */
    453 		return (ENODEV);
    454 
    455 	case Fctty:
    456 		return (cttyopen(devctty, ap->a_mode, 0, ap->a_p));
    457 	case Froot:
    458 	case Fdevfd:
    459 	case Flink:
    460 		break;
    461 	}
    462 
    463 	return (0);
    464 }
    465 
    466 static int
    467 fdesc_attr(fd, vap, cred, p)
    468 	int fd;
    469 	struct vattr *vap;
    470 	struct ucred *cred;
    471 	struct proc *p;
    472 {
    473 	struct filedesc *fdp = p->p_fd;
    474 	struct file *fp;
    475 	struct stat stb;
    476 	int error;
    477 
    478 	if ((fp = fd_getfile(fdp, fd)) == NULL)
    479 		return (EBADF);
    480 
    481 	switch (fp->f_type) {
    482 	case DTYPE_VNODE:
    483 		error = VOP_GETATTR((struct vnode *) fp->f_data, vap, cred, p);
    484 		if (error == 0 && vap->va_type == VDIR) {
    485 			/*
    486 			 * directories can cause loops in the namespace,
    487 			 * so turn off the 'x' bits to avoid trouble.
    488 			 */
    489 			vap->va_mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
    490 		}
    491 		break;
    492 
    493 	case DTYPE_SOCKET:
    494 	case DTYPE_PIPE:
    495 	case DTYPE_KQUEUE:
    496 		FILE_USE(fp);
    497 		error = (*fp->f_ops->fo_stat)(fp, &stb, p);
    498 		FILE_UNUSE(fp, p);
    499 		if (error == 0) {
    500 			vattr_null(vap);
    501 			if (fp->f_type == DTYPE_SOCKET)
    502 				vap->va_type = VSOCK;
    503 			else
    504 				vap->va_type = VFIFO;
    505 			vap->va_mode = stb.st_mode;
    506 			vap->va_nlink = stb.st_nlink;
    507 			vap->va_uid = stb.st_uid;
    508 			vap->va_gid = stb.st_gid;
    509 			vap->va_fsid = stb.st_dev;
    510 			vap->va_fileid = stb.st_ino;
    511 			vap->va_size = stb.st_size;
    512 			vap->va_blocksize = stb.st_blksize;
    513 			vap->va_atime = stb.st_atimespec;
    514 			vap->va_mtime = stb.st_mtimespec;
    515 			vap->va_ctime = stb.st_ctimespec;
    516 			vap->va_gen = stb.st_gen;
    517 			vap->va_flags = stb.st_flags;
    518 			vap->va_rdev = stb.st_rdev;
    519 			vap->va_bytes = stb.st_blocks * stb.st_blksize;
    520 		}
    521 		break;
    522 
    523 	default:
    524 		panic("fdesc attr");
    525 		break;
    526 	}
    527 
    528 	return (error);
    529 }
    530 
    531 int
    532 fdesc_getattr(v)
    533 	void *v;
    534 {
    535 	struct vop_getattr_args /* {
    536 		struct vnode *a_vp;
    537 		struct vattr *a_vap;
    538 		struct ucred *a_cred;
    539 		struct proc *a_p;
    540 	} */ *ap = v;
    541 	struct vnode *vp = ap->a_vp;
    542 	struct vattr *vap = ap->a_vap;
    543 	unsigned fd;
    544 	int error = 0;
    545 
    546 	switch (VTOFDESC(vp)->fd_type) {
    547 	case Froot:
    548 	case Fdevfd:
    549 	case Flink:
    550 	case Fctty:
    551 		VATTR_NULL(vap);
    552 		vap->va_fileid = VTOFDESC(vp)->fd_ix;
    553 
    554 #define R_ALL (S_IRUSR|S_IRGRP|S_IROTH)
    555 #define W_ALL (S_IWUSR|S_IWGRP|S_IWOTH)
    556 #define X_ALL (S_IXUSR|S_IXGRP|S_IXOTH)
    557 
    558 		switch (VTOFDESC(vp)->fd_type) {
    559 		case Flink:
    560 			vap->va_mode = R_ALL|X_ALL;
    561 			vap->va_type = VLNK;
    562 			vap->va_rdev = 0;
    563 			vap->va_nlink = 1;
    564 			vap->va_size = strlen(VTOFDESC(vp)->fd_link);
    565 			break;
    566 
    567 		case Fctty:
    568 			vap->va_mode = R_ALL|W_ALL;
    569 			vap->va_type = VCHR;
    570 			vap->va_rdev = devctty;
    571 			vap->va_nlink = 1;
    572 			vap->va_size = 0;
    573 			break;
    574 
    575 		default:
    576 			vap->va_mode = R_ALL|X_ALL;
    577 			vap->va_type = VDIR;
    578 			vap->va_rdev = 0;
    579 			vap->va_nlink = 2;
    580 			vap->va_size = DEV_BSIZE;
    581 			break;
    582 		}
    583 		vap->va_uid = 0;
    584 		vap->va_gid = 0;
    585 		vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
    586 		vap->va_blocksize = DEV_BSIZE;
    587 		vap->va_atime.tv_sec = boottime.tv_sec;
    588 		vap->va_atime.tv_nsec = 0;
    589 		vap->va_mtime = vap->va_atime;
    590 		vap->va_ctime = vap->va_mtime;
    591 		vap->va_gen = 0;
    592 		vap->va_flags = 0;
    593 		vap->va_bytes = 0;
    594 		break;
    595 
    596 	case Fdesc:
    597 		fd = VTOFDESC(vp)->fd_fd;
    598 		error = fdesc_attr(fd, vap, ap->a_cred, ap->a_p);
    599 		break;
    600 
    601 	default:
    602 		panic("fdesc_getattr");
    603 		break;
    604 	}
    605 
    606 	if (error == 0)
    607 		vp->v_type = vap->va_type;
    608 
    609 	return (error);
    610 }
    611 
    612 int
    613 fdesc_setattr(v)
    614 	void *v;
    615 {
    616 	struct vop_setattr_args /* {
    617 		struct vnode *a_vp;
    618 		struct vattr *a_vap;
    619 		struct ucred *a_cred;
    620 		struct proc *a_p;
    621 	} */ *ap = v;
    622 	struct filedesc *fdp = ap->a_p->p_fd;
    623 	struct file *fp;
    624 	unsigned fd;
    625 	int error;
    626 
    627 	/*
    628 	 * Can't mess with the root vnode
    629 	 */
    630 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    631 	case Fdesc:
    632 		break;
    633 
    634 	case Fctty:
    635 		return (0);
    636 
    637 	default:
    638 		return (EACCES);
    639 	}
    640 
    641 	fd = VTOFDESC(ap->a_vp)->fd_fd;
    642 	if ((fp = fd_getfile(fdp, fd)) == NULL)
    643 		return (EBADF);
    644 
    645 	/*
    646 	 * Can setattr the underlying vnode, but not sockets!
    647 	 */
    648 	switch (fp->f_type) {
    649 	case DTYPE_VNODE:
    650 	case DTYPE_SOCKET:
    651 	case DTYPE_KQUEUE:
    652 		error = 0;
    653 		break;
    654 
    655 	default:
    656 		panic("fdesc setattr");
    657 		break;
    658 	}
    659 
    660 	return (error);
    661 }
    662 
    663 #define UIO_MX 32
    664 
    665 struct fdesc_target {
    666 	ino_t ft_fileno;
    667 	u_char ft_type;
    668 	u_char ft_namlen;
    669 	char *ft_name;
    670 } fdesc_targets[] = {
    671 /* NOTE: The name must be less than UIO_MX-16 chars in length */
    672 #define N(s) sizeof(s)-1, s
    673 	{ FD_DEVFD,  DT_DIR,     N("fd")     },
    674 	{ FD_STDIN,  DT_LNK,     N("stdin")  },
    675 	{ FD_STDOUT, DT_LNK,     N("stdout") },
    676 	{ FD_STDERR, DT_LNK,     N("stderr") },
    677 	{ FD_CTTY,   DT_UNKNOWN, N("tty")    },
    678 #undef N
    679 };
    680 static int nfdesc_targets = sizeof(fdesc_targets) / sizeof(fdesc_targets[0]);
    681 
    682 int
    683 fdesc_readdir(v)
    684 	void *v;
    685 {
    686 	struct vop_readdir_args /* {
    687 		struct vnode *a_vp;
    688 		struct uio *a_uio;
    689 		struct ucred *a_cred;
    690 		int *a_eofflag;
    691 		off_t **a_cookies;
    692 		int *a_ncookies;
    693 	} */ *ap = v;
    694 	struct uio *uio = ap->a_uio;
    695 	struct dirent d;
    696 	struct filedesc *fdp;
    697 	off_t i;
    698 	int error;
    699 	off_t *cookies = NULL;
    700 	int ncookies = 0;
    701 
    702 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    703 	case Fctty:
    704 		return (0);
    705 
    706 	case Fdesc:
    707 		return (ENOTDIR);
    708 
    709 	default:
    710 		break;
    711 	}
    712 
    713 	fdp = uio->uio_procp->p_fd;
    714 
    715 	if (uio->uio_resid < UIO_MX)
    716 		return (EINVAL);
    717 	if (uio->uio_offset < 0)
    718 		return (EINVAL);
    719 
    720 	error = 0;
    721 	i = uio->uio_offset;
    722 	memset((caddr_t)&d, 0, UIO_MX);
    723 	d.d_reclen = UIO_MX;
    724 	if (ap->a_ncookies)
    725 		ncookies = (uio->uio_resid / UIO_MX);
    726 
    727 	if (VTOFDESC(ap->a_vp)->fd_type == Froot) {
    728 		struct fdesc_target *ft;
    729 
    730 		if (i >= nfdesc_targets)
    731 			return 0;
    732 
    733 		if (ap->a_ncookies) {
    734 			ncookies = min(ncookies, (nfdesc_targets - i));
    735 			cookies = malloc(ncookies * sizeof(off_t),
    736 			    M_TEMP, M_WAITOK);
    737 			*ap->a_cookies = cookies;
    738 			*ap->a_ncookies = ncookies;
    739 		}
    740 
    741 		for (ft = &fdesc_targets[i];
    742 		     uio->uio_resid >= UIO_MX && i < nfdesc_targets; ft++, i++) {
    743 			switch (ft->ft_fileno) {
    744 			case FD_CTTY:
    745 				if (cttyvp(uio->uio_procp) == NULL)
    746 					continue;
    747 				break;
    748 
    749 			case FD_STDIN:
    750 			case FD_STDOUT:
    751 			case FD_STDERR:
    752 				if ((ft->ft_fileno - FD_STDIN) >= fdp->fd_nfiles)
    753 					continue;
    754 				if (fdp->fd_ofiles[ft->ft_fileno - FD_STDIN] == NULL
    755 				    || FILE_IS_USABLE(fdp->fd_ofiles[ft->ft_fileno - FD_STDIN]) == 0)
    756 					continue;
    757 				break;
    758 			}
    759 
    760 			d.d_fileno = ft->ft_fileno;
    761 			d.d_namlen = ft->ft_namlen;
    762 			memcpy(d.d_name, ft->ft_name, ft->ft_namlen + 1);
    763 			d.d_type = ft->ft_type;
    764 
    765 			if ((error = uiomove((caddr_t)&d, UIO_MX, uio)) != 0)
    766 				break;
    767 			if (cookies)
    768 				*cookies++ = i + 1;
    769 		}
    770 	} else {
    771 		if (ap->a_ncookies) {
    772 			ncookies = min(ncookies, (fdp->fd_nfiles + 2));
    773 			cookies = malloc(ncookies * sizeof(off_t),
    774 			    M_TEMP, M_WAITOK);
    775 			*ap->a_cookies = cookies;
    776 			*ap->a_ncookies = ncookies;
    777 		}
    778 		for (; i - 2 < fdp->fd_nfiles && uio->uio_resid >= UIO_MX;
    779 		     i++) {
    780 			switch (i) {
    781 			case 0:
    782 			case 1:
    783 				d.d_fileno = FD_ROOT;		/* XXX */
    784 				d.d_namlen = i + 1;
    785 				memcpy(d.d_name, "..", d.d_namlen);
    786 				d.d_name[i + 1] = '\0';
    787 				d.d_type = DT_DIR;
    788 				break;
    789 
    790 			default:
    791 				if (fdp->fd_ofiles[i - 2] == NULL ||
    792 				    FILE_IS_USABLE(fdp->fd_ofiles[i - 2]) == 0)
    793 					continue;
    794 				d.d_fileno = i - 2 + FD_STDIN;
    795 				d.d_namlen = sprintf(d.d_name, "%d", (int) i - 2);
    796 				d.d_type = DT_UNKNOWN;
    797 				break;
    798 			}
    799 
    800 			if ((error = uiomove((caddr_t)&d, UIO_MX, uio)) != 0)
    801 				break;
    802 			if (cookies)
    803 				*cookies++ = i + 1;
    804 		}
    805 	}
    806 
    807 	if (ap->a_ncookies && error) {
    808 		free(*ap->a_cookies, M_TEMP);
    809 		*ap->a_ncookies = 0;
    810 		*ap->a_cookies = NULL;
    811 	}
    812 
    813 	uio->uio_offset = i;
    814 	return (error);
    815 }
    816 
    817 int
    818 fdesc_readlink(v)
    819 	void *v;
    820 {
    821 	struct vop_readlink_args /* {
    822 		struct vnode *a_vp;
    823 		struct uio *a_uio;
    824 		struct ucred *a_cred;
    825 	} */ *ap = v;
    826 	struct vnode *vp = ap->a_vp;
    827 	int error;
    828 
    829 	if (vp->v_type != VLNK)
    830 		return (EPERM);
    831 
    832 	if (VTOFDESC(vp)->fd_type == Flink) {
    833 		char *ln = VTOFDESC(vp)->fd_link;
    834 		error = uiomove(ln, strlen(ln), ap->a_uio);
    835 	} else {
    836 		error = EOPNOTSUPP;
    837 	}
    838 
    839 	return (error);
    840 }
    841 
    842 int
    843 fdesc_read(v)
    844 	void *v;
    845 {
    846 	struct vop_read_args /* {
    847 		struct vnode *a_vp;
    848 		struct uio *a_uio;
    849 		int  a_ioflag;
    850 		struct ucred *a_cred;
    851 	} */ *ap = v;
    852 	int error = EOPNOTSUPP;
    853 	struct vnode *vp = ap->a_vp;
    854 
    855 	switch (VTOFDESC(vp)->fd_type) {
    856 	case Fctty:
    857 		VOP_UNLOCK(vp, 0);
    858 		error = cttyread(devctty, ap->a_uio, ap->a_ioflag);
    859 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
    860 		break;
    861 
    862 	default:
    863 		error = EOPNOTSUPP;
    864 		break;
    865 	}
    866 
    867 	return (error);
    868 }
    869 
    870 int
    871 fdesc_write(v)
    872 	void *v;
    873 {
    874 	struct vop_write_args /* {
    875 		struct vnode *a_vp;
    876 		struct uio *a_uio;
    877 		int  a_ioflag;
    878 		struct ucred *a_cred;
    879 	} */ *ap = v;
    880 	int error = EOPNOTSUPP;
    881 	struct vnode *vp = ap->a_vp;
    882 
    883 	switch (VTOFDESC(vp)->fd_type) {
    884 	case Fctty:
    885 		VOP_UNLOCK(vp, 0);
    886 		error = cttywrite(devctty, ap->a_uio, ap->a_ioflag);
    887 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
    888 		break;
    889 
    890 	default:
    891 		error = EOPNOTSUPP;
    892 		break;
    893 	}
    894 
    895 	return (error);
    896 }
    897 
    898 int
    899 fdesc_ioctl(v)
    900 	void *v;
    901 {
    902 	struct vop_ioctl_args /* {
    903 		struct vnode *a_vp;
    904 		u_long a_command;
    905 		caddr_t  a_data;
    906 		int  a_fflag;
    907 		struct ucred *a_cred;
    908 		struct proc *a_p;
    909 	} */ *ap = v;
    910 	int error = EOPNOTSUPP;
    911 
    912 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    913 	case Fctty:
    914 		error = cttyioctl(devctty, ap->a_command, ap->a_data,
    915 				  ap->a_fflag, ap->a_p);
    916 		break;
    917 
    918 	default:
    919 		error = EOPNOTSUPP;
    920 		break;
    921 	}
    922 
    923 	return (error);
    924 }
    925 
    926 int
    927 fdesc_poll(v)
    928 	void *v;
    929 {
    930 	struct vop_poll_args /* {
    931 		struct vnode *a_vp;
    932 		int a_events;
    933 		struct proc *a_p;
    934 	} */ *ap = v;
    935 	int revents;
    936 
    937 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    938 	case Fctty:
    939 		revents = cttypoll(devctty, ap->a_events, ap->a_p);
    940 		break;
    941 
    942 	default:
    943 		revents = genfs_poll(v);
    944 		break;
    945 	}
    946 
    947 	return (revents);
    948 }
    949 
    950 int
    951 fdesc_kqfilter(v)
    952 	void *v;
    953 {
    954 	struct vop_kqfilter_args /* {
    955 		struct vnode *a_vp;
    956 		struct knote *a_kn;
    957 	} */ *ap = v;
    958 	int rv;
    959 
    960 	switch (VTOFDESC(ap->a_vp)->fd_type) {
    961 	case Fctty:
    962 		rv = cttykqfilter(devctty, ap->a_kn);
    963 		break;
    964 
    965 	default:
    966 		rv = 1;		/* XXXLUKEM (thorpej) */
    967 		break;
    968 	}
    969 
    970 	return (rv);
    971 }
    972 
    973 int
    974 fdesc_inactive(v)
    975 	void *v;
    976 {
    977 	struct vop_inactive_args /* {
    978 		struct vnode *a_vp;
    979 		struct proc *a_p;
    980 	} */ *ap = v;
    981 	struct vnode *vp = ap->a_vp;
    982 
    983 	/*
    984 	 * Clear out the v_type field to avoid
    985 	 * nasty things happening in vgone().
    986 	 */
    987 	VOP_UNLOCK(vp, 0);
    988 	vp->v_type = VNON;
    989 	return (0);
    990 }
    991 
    992 int
    993 fdesc_reclaim(v)
    994 	void *v;
    995 {
    996 	struct vop_reclaim_args /* {
    997 		struct vnode *a_vp;
    998 	} */ *ap = v;
    999 	struct vnode *vp = ap->a_vp;
   1000 	struct fdescnode *fd = VTOFDESC(vp);
   1001 
   1002 	LIST_REMOVE(fd, fd_hash);
   1003 	FREE(vp->v_data, M_TEMP);
   1004 	vp->v_data = 0;
   1005 
   1006 	return (0);
   1007 }
   1008 
   1009 /*
   1010  * Return POSIX pathconf information applicable to special devices.
   1011  */
   1012 int
   1013 fdesc_pathconf(v)
   1014 	void *v;
   1015 {
   1016 	struct vop_pathconf_args /* {
   1017 		struct vnode *a_vp;
   1018 		int a_name;
   1019 		register_t *a_retval;
   1020 	} */ *ap = v;
   1021 
   1022 	switch (ap->a_name) {
   1023 	case _PC_LINK_MAX:
   1024 		*ap->a_retval = LINK_MAX;
   1025 		return (0);
   1026 	case _PC_MAX_CANON:
   1027 		*ap->a_retval = MAX_CANON;
   1028 		return (0);
   1029 	case _PC_MAX_INPUT:
   1030 		*ap->a_retval = MAX_INPUT;
   1031 		return (0);
   1032 	case _PC_PIPE_BUF:
   1033 		*ap->a_retval = PIPE_BUF;
   1034 		return (0);
   1035 	case _PC_CHOWN_RESTRICTED:
   1036 		*ap->a_retval = 1;
   1037 		return (0);
   1038 	case _PC_VDISABLE:
   1039 		*ap->a_retval = _POSIX_VDISABLE;
   1040 		return (0);
   1041 	case _PC_SYNC_IO:
   1042 		*ap->a_retval = 1;
   1043 		return (0);
   1044 	default:
   1045 		return (EINVAL);
   1046 	}
   1047 	/* NOTREACHED */
   1048 }
   1049 
   1050 /*
   1051  * Print out the contents of a /dev/fd vnode.
   1052  */
   1053 /* ARGSUSED */
   1054 int
   1055 fdesc_print(v)
   1056 	void *v;
   1057 {
   1058 	printf("tag VT_NON, fdesc vnode\n");
   1059 	return (0);
   1060 }
   1061 
   1062 int
   1063 fdesc_link(v)
   1064 	void *v;
   1065 {
   1066 	struct vop_link_args /* {
   1067 		struct vnode *a_dvp;
   1068 		struct vnode *a_vp;
   1069 		struct componentname *a_cnp;
   1070 	} */ *ap = v;
   1071 
   1072 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
   1073 	vput(ap->a_dvp);
   1074 	return (EROFS);
   1075 }
   1076 
   1077 int
   1078 fdesc_symlink(v)
   1079 	void *v;
   1080 {
   1081 	struct vop_symlink_args /* {
   1082 		struct vnode *a_dvp;
   1083 		struct vnode **a_vpp;
   1084 		struct componentname *a_cnp;
   1085 		struct vattr *a_vap;
   1086 		char *a_target;
   1087 	} */ *ap = v;
   1088 
   1089 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
   1090 	vput(ap->a_dvp);
   1091 	return (EROFS);
   1092 }
   1093