xref: /netbsd-src/sys/miscfs/kernfs/kernfs_vnops.c (revision 76dfffe33547c37f8bdd446e3e4ab0f3c16cea4b)
1 /*	$NetBSD: kernfs_vnops.c,v 1.48 1996/10/25 21:58:00 cgd 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  *	@(#)kernfs_vnops.c	8.9 (Berkeley) 6/15/94
39  */
40 
41 /*
42  * Kernel parameter filesystem (/kern)
43  */
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/vmmeter.h>
49 #include <sys/types.h>
50 #include <sys/time.h>
51 #include <sys/proc.h>
52 #include <sys/vnode.h>
53 #include <sys/malloc.h>
54 #include <sys/file.h>
55 #include <sys/stat.h>
56 #include <sys/mount.h>
57 #include <sys/namei.h>
58 #include <sys/buf.h>
59 #include <sys/dirent.h>
60 #include <sys/msgbuf.h>
61 
62 #include <miscfs/genfs/genfs.h>
63 #include <miscfs/kernfs/kernfs.h>
64 
65 #define KSTRING	256		/* Largest I/O available via this filesystem */
66 #define	UIO_MX 32
67 
68 #define	READ_MODE	(S_IRUSR|S_IRGRP|S_IROTH)
69 #define	WRITE_MODE	(S_IWUSR|S_IRUSR|S_IRGRP|S_IROTH)
70 #define DIR_MODE	(S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
71 
72 struct kern_target {
73 	u_char kt_type;
74 	u_char kt_namlen;
75 	char *kt_name;
76 	void *kt_data;
77 #define	KTT_NULL	 1
78 #define	KTT_TIME	 5
79 #define KTT_INT		17
80 #define	KTT_STRING	31
81 #define KTT_HOSTNAME	47
82 #define KTT_AVENRUN	53
83 #define KTT_DEVICE	71
84 #define	KTT_MSGBUF	89
85 	u_char kt_tag;
86 	u_char kt_vtype;
87 	mode_t kt_mode;
88 } kern_targets[] = {
89 /* NOTE: The name must be less than UIO_MX-16 chars in length */
90 #define N(s) sizeof(s)-1, s
91      /*        name            data          tag           type  ro/rw */
92      { DT_DIR, N("."),         0,            KTT_NULL,     VDIR, DIR_MODE   },
93      { DT_DIR, N(".."),        0,            KTT_NULL,     VDIR, DIR_MODE   },
94      { DT_REG, N("boottime"),  &boottime.tv_sec, KTT_INT,  VREG, READ_MODE  },
95      { DT_REG, N("copyright"), copyright,    KTT_STRING,   VREG, READ_MODE  },
96      { DT_REG, N("hostname"),  0,            KTT_HOSTNAME, VREG, WRITE_MODE },
97      { DT_REG, N("hz"),        &hz,          KTT_INT,      VREG, READ_MODE  },
98      { DT_REG, N("loadavg"),   0,            KTT_AVENRUN,  VREG, READ_MODE  },
99      { DT_REG, N("msgbuf"),    0,	     KTT_MSGBUF,   VREG, READ_MODE  },
100      { DT_REG, N("pagesize"),  &cnt.v_page_size, KTT_INT,  VREG, READ_MODE  },
101      { DT_REG, N("physmem"),   &physmem,     KTT_INT,      VREG, READ_MODE  },
102 #if 0
103      { DT_DIR, N("root"),      0,            KTT_NULL,     VDIR, DIR_MODE   },
104 #endif
105      { DT_BLK, N("rootdev"),   &rootdev,     KTT_DEVICE,   VBLK, READ_MODE  },
106      { DT_CHR, N("rrootdev"),  &rrootdev,    KTT_DEVICE,   VCHR, READ_MODE  },
107      { DT_REG, N("time"),      0,            KTT_TIME,     VREG, READ_MODE  },
108      { DT_REG, N("version"),   version,      KTT_STRING,   VREG, READ_MODE  },
109 #undef N
110 };
111 static int nkern_targets = sizeof(kern_targets) / sizeof(kern_targets[0]);
112 
113 int	kernfs_lookup	__P((void *));
114 #define	kernfs_create	genfs_eopnotsupp
115 #define	kernfs_mknod	genfs_eopnotsupp
116 #define	kernfs_open	genfs_nullop
117 #define	kernfs_close	genfs_nullop
118 int	kernfs_access	__P((void *));
119 int	kernfs_getattr	__P((void *));
120 int	kernfs_setattr	__P((void *));
121 int	kernfs_read	__P((void *));
122 int	kernfs_write	__P((void *));
123 #define	kernfs_ioctl	genfs_eopnotsupp
124 #define	kernfs_poll	genfs_poll
125 #define	kernfs_mmap	genfs_eopnotsupp
126 #define	kernfs_fsync	genfs_nullop
127 #define	kernfs_seek	genfs_nullop
128 #define	kernfs_remove	genfs_eopnotsupp
129 int	kernfs_link	__P((void *));
130 #define	kernfs_rename	genfs_eopnotsupp
131 #define	kernfs_mkdir	genfs_eopnotsupp
132 #define	kernfs_rmdir	genfs_eopnotsupp
133 int	kernfs_symlink	__P((void *));
134 int	kernfs_readdir	__P((void *));
135 #define	kernfs_readlink	genfs_eopnotsupp
136 #define	kernfs_abortop	genfs_abortop
137 int	kernfs_inactive	__P((void *));
138 int	kernfs_reclaim	__P((void *));
139 #define	kernfs_lock	genfs_nullop
140 #define	kernfs_unlock	genfs_nullop
141 #define	kernfs_bmap	genfs_badop
142 #define	kernfs_strategy	genfs_badop
143 int	kernfs_print	__P((void *));
144 #define	kernfs_islocked	genfs_nullop
145 int	kernfs_pathconf	__P((void *));
146 #define	kernfs_advlock	genfs_eopnotsupp
147 #define	kernfs_blkatoff	genfs_eopnotsupp
148 #define	kernfs_valloc	genfs_eopnotsupp
149 #define	kernfs_vfree	genfs_nullop
150 #define	kernfs_truncate	genfs_eopnotsupp
151 #define	kernfs_update	genfs_nullop
152 #define	kernfs_bwrite	genfs_eopnotsupp
153 
154 int	kernfs_xread __P((struct kern_target *, int, char **, int));
155 int	kernfs_xwrite __P((struct kern_target *, char *, int));
156 
157 int (**kernfs_vnodeop_p) __P((void *));
158 struct vnodeopv_entry_desc kernfs_vnodeop_entries[] = {
159 	{ &vop_default_desc, vn_default_error },
160 	{ &vop_lookup_desc, kernfs_lookup },		/* lookup */
161 	{ &vop_create_desc, kernfs_create },		/* create */
162 	{ &vop_mknod_desc, kernfs_mknod },		/* mknod */
163 	{ &vop_open_desc, kernfs_open },		/* open */
164 	{ &vop_close_desc, kernfs_close },		/* close */
165 	{ &vop_access_desc, kernfs_access },		/* access */
166 	{ &vop_getattr_desc, kernfs_getattr },		/* getattr */
167 	{ &vop_setattr_desc, kernfs_setattr },		/* setattr */
168 	{ &vop_read_desc, kernfs_read },		/* read */
169 	{ &vop_write_desc, kernfs_write },		/* write */
170 	{ &vop_ioctl_desc, kernfs_ioctl },		/* ioctl */
171 	{ &vop_poll_desc, kernfs_poll },		/* poll */
172 	{ &vop_mmap_desc, kernfs_mmap },		/* mmap */
173 	{ &vop_fsync_desc, kernfs_fsync },		/* fsync */
174 	{ &vop_seek_desc, kernfs_seek },		/* seek */
175 	{ &vop_remove_desc, kernfs_remove },		/* remove */
176 	{ &vop_link_desc, kernfs_link },		/* link */
177 	{ &vop_rename_desc, kernfs_rename },		/* rename */
178 	{ &vop_mkdir_desc, kernfs_mkdir },		/* mkdir */
179 	{ &vop_rmdir_desc, kernfs_rmdir },		/* rmdir */
180 	{ &vop_symlink_desc, kernfs_symlink },		/* symlink */
181 	{ &vop_readdir_desc, kernfs_readdir },		/* readdir */
182 	{ &vop_readlink_desc, kernfs_readlink },	/* readlink */
183 	{ &vop_abortop_desc, kernfs_abortop },		/* abortop */
184 	{ &vop_inactive_desc, kernfs_inactive },	/* inactive */
185 	{ &vop_reclaim_desc, kernfs_reclaim },		/* reclaim */
186 	{ &vop_lock_desc, kernfs_lock },		/* lock */
187 	{ &vop_unlock_desc, kernfs_unlock },		/* unlock */
188 	{ &vop_bmap_desc, kernfs_bmap },		/* bmap */
189 	{ &vop_strategy_desc, kernfs_strategy },	/* strategy */
190 	{ &vop_print_desc, kernfs_print },		/* print */
191 	{ &vop_islocked_desc, kernfs_islocked },	/* islocked */
192 	{ &vop_pathconf_desc, kernfs_pathconf },	/* pathconf */
193 	{ &vop_advlock_desc, kernfs_advlock },		/* advlock */
194 	{ &vop_blkatoff_desc, kernfs_blkatoff },	/* blkatoff */
195 	{ &vop_valloc_desc, kernfs_valloc },		/* valloc */
196 	{ &vop_vfree_desc, kernfs_vfree },		/* vfree */
197 	{ &vop_truncate_desc, kernfs_truncate },	/* truncate */
198 	{ &vop_update_desc, kernfs_update },		/* update */
199 	{ &vop_bwrite_desc, kernfs_bwrite },		/* bwrite */
200 	{ (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
201 };
202 struct vnodeopv_desc kernfs_vnodeop_opv_desc =
203 	{ &kernfs_vnodeop_p, kernfs_vnodeop_entries };
204 
205 int
206 kernfs_xread(kt, off, bufp, len)
207 	struct kern_target *kt;
208 	int off;
209 	char **bufp;
210 	int len;
211 {
212 
213 	switch (kt->kt_tag) {
214 	case KTT_TIME: {
215 		struct timeval tv;
216 
217 		microtime(&tv);
218 		sprintf(*bufp, "%ld %ld\n", tv.tv_sec, tv.tv_usec);
219 		break;
220 	}
221 
222 	case KTT_INT: {
223 		int *ip = kt->kt_data;
224 
225 		sprintf(*bufp, "%d\n", *ip);
226 		break;
227 	}
228 
229 	case KTT_STRING: {
230 		char *cp = kt->kt_data;
231 
232 		*bufp = cp;
233 		break;
234 	}
235 
236 	case KTT_MSGBUF: {
237 		extern struct msgbuf *msgbufp;
238 		long n;
239 
240 		if (off >= MSG_BSIZE)
241 			return (0);
242 		n = msgbufp->msg_bufx + off;
243 		if (n >= MSG_BSIZE)
244 			n -= MSG_BSIZE;
245 		len = min(MSG_BSIZE - n, MSG_BSIZE - off);
246 		*bufp = msgbufp->msg_bufc + n;
247 		return (len);
248 	}
249 
250 	case KTT_HOSTNAME: {
251 		char *cp = hostname;
252 		int xlen = hostnamelen;
253 
254 		if (xlen >= (len-2))
255 			return (EINVAL);
256 
257 		bcopy(cp, *bufp, xlen);
258 		(*bufp)[xlen] = '\n';
259 		(*bufp)[xlen+1] = '\0';
260 		break;
261 	}
262 
263 	case KTT_AVENRUN:
264 		averunnable.fscale = FSCALE;
265 		sprintf(*bufp, "%d %d %d %ld\n",
266 		    averunnable.ldavg[0], averunnable.ldavg[1],
267 		    averunnable.ldavg[2], averunnable.fscale);
268 		break;
269 
270 	default:
271 		return (0);
272 	}
273 
274 	len = strlen(*bufp);
275 	if (len <= off)
276 		return (0);
277 	*bufp += off;
278 	return (len - off);
279 }
280 
281 int
282 kernfs_xwrite(kt, buf, len)
283 	struct kern_target *kt;
284 	char *buf;
285 	int len;
286 {
287 
288 	switch (kt->kt_tag) {
289 	case KTT_HOSTNAME:
290 		if (buf[len-1] == '\n')
291 			--len;
292 		bcopy(buf, hostname, len);
293 		hostname[len] = '\0';
294 		hostnamelen = len;
295 		return (0);
296 
297 	default:
298 		return (EIO);
299 	}
300 }
301 
302 
303 /*
304  * vp is the current namei directory
305  * ndp is the name to locate in that directory...
306  */
307 int
308 kernfs_lookup(v)
309 	void *v;
310 {
311 	struct vop_lookup_args /* {
312 		struct vnode * a_dvp;
313 		struct vnode ** a_vpp;
314 		struct componentname * a_cnp;
315 	} */ *ap = v;
316 	struct componentname *cnp = ap->a_cnp;
317 	struct vnode **vpp = ap->a_vpp;
318 	struct vnode *dvp = ap->a_dvp;
319 	const char *pname = cnp->cn_nameptr;
320 	struct kern_target *kt;
321 	struct vnode *fvp;
322 	int error, i;
323 
324 #ifdef KERNFS_DIAGNOSTIC
325 	printf("kernfs_lookup(%x)\n", ap);
326 	printf("kernfs_lookup(dp = %x, vpp = %x, cnp = %x)\n", dvp, vpp, ap->a_cnp);
327 	printf("kernfs_lookup(%s)\n", pname);
328 #endif
329 
330 	*vpp = NULLVP;
331 
332 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
333 		return (EROFS);
334 
335 	if (cnp->cn_namelen == 1 && *pname == '.') {
336 		*vpp = dvp;
337 		VREF(dvp);
338 		/*VOP_LOCK(dvp);*/
339 		return (0);
340 	}
341 
342 #if 0
343 	if (cnp->cn_namelen == 4 && bcmp(pname, "root", 4) == 0) {
344 		*vpp = rootdir;
345 		VREF(rootdir);
346 		VOP_LOCK(rootdir);
347 		return (0);
348 	}
349 #endif
350 
351 	for (kt = kern_targets, i = 0; i < nkern_targets; kt++, i++) {
352 		if (cnp->cn_namelen == kt->kt_namlen &&
353 		    bcmp(kt->kt_name, pname, cnp->cn_namelen) == 0)
354 			goto found;
355 	}
356 
357 #ifdef KERNFS_DIAGNOSTIC
358 	printf("kernfs_lookup: i = %d, failed", i);
359 #endif
360 
361 	return (cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS);
362 
363 found:
364 	if (kt->kt_tag == KTT_DEVICE) {
365 		dev_t *dp = kt->kt_data;
366 	loop:
367 		if (*dp == NODEV || !vfinddev(*dp, kt->kt_vtype, &fvp))
368 			return (ENOENT);
369 		*vpp = fvp;
370 		if (vget(fvp, 1))
371 			goto loop;
372 		return (0);
373 	}
374 
375 #ifdef KERNFS_DIAGNOSTIC
376 	printf("kernfs_lookup: allocate new vnode\n");
377 #endif
378 	error = getnewvnode(VT_KERNFS, dvp->v_mount, kernfs_vnodeop_p, &fvp);
379 	if (error)
380 		return (error);
381 
382 	MALLOC(fvp->v_data, void *, sizeof(struct kernfs_node), M_TEMP,
383 	    M_WAITOK);
384 	VTOKERN(fvp)->kf_kt = kt;
385 	fvp->v_type = kt->kt_vtype;
386 	*vpp = fvp;
387 
388 #ifdef KERNFS_DIAGNOSTIC
389 	printf("kernfs_lookup: newvp = %x\n", fvp);
390 #endif
391 	return (0);
392 }
393 
394 int
395 kernfs_access(v)
396 	void *v;
397 {
398 	struct vop_access_args /* {
399 		struct vnode *a_vp;
400 		int a_mode;
401 		struct ucred *a_cred;
402 		struct proc *a_p;
403 	} */ *ap = v;
404 	struct vnode *vp = ap->a_vp;
405 	mode_t fmode =
406 	    (vp->v_flag & VROOT) ? DIR_MODE : VTOKERN(vp)->kf_kt->kt_mode;
407 
408 	return (vaccess(fmode, (uid_t)0, (gid_t)0, ap->a_mode, ap->a_cred));
409 }
410 
411 int
412 kernfs_getattr(v)
413 	void *v;
414 {
415 	struct vop_getattr_args /* {
416 		struct vnode *a_vp;
417 		struct vattr *a_vap;
418 		struct ucred *a_cred;
419 		struct proc *a_p;
420 	} */ *ap = v;
421 	struct vnode *vp = ap->a_vp;
422 	struct vattr *vap = ap->a_vap;
423 	struct timeval tv;
424 	int error = 0;
425 	char strbuf[KSTRING], *buf;
426 
427 	bzero((caddr_t) vap, sizeof(*vap));
428 	vattr_null(vap);
429 	vap->va_uid = 0;
430 	vap->va_gid = 0;
431 	vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
432 	vap->va_size = 0;
433 	vap->va_blocksize = DEV_BSIZE;
434 	microtime(&tv);
435 	TIMEVAL_TO_TIMESPEC(&tv, &vap->va_atime);
436 	vap->va_mtime = vap->va_atime;
437 	vap->va_ctime = vap->va_ctime;
438 	vap->va_gen = 0;
439 	vap->va_flags = 0;
440 	vap->va_rdev = 0;
441 	vap->va_bytes = 0;
442 
443 	if (vp->v_flag & VROOT) {
444 #ifdef KERNFS_DIAGNOSTIC
445 		printf("kernfs_getattr: stat rootdir\n");
446 #endif
447 		vap->va_type = VDIR;
448 		vap->va_mode = DIR_MODE;
449 		vap->va_nlink = 2;
450 		vap->va_fileid = 2;
451 		vap->va_size = DEV_BSIZE;
452 	} else {
453 		struct kern_target *kt = VTOKERN(vp)->kf_kt;
454 		int nbytes, total;
455 #ifdef KERNFS_DIAGNOSTIC
456 		printf("kernfs_getattr: stat target %s\n", kt->kt_name);
457 #endif
458 		vap->va_type = kt->kt_vtype;
459 		vap->va_mode = kt->kt_mode;
460 		vap->va_nlink = 1;
461 		vap->va_fileid = 3 + (kt - kern_targets);
462 		total = 0;
463 		while (buf = strbuf,
464 		       nbytes = kernfs_xread(kt, total, &buf, sizeof(strbuf)))
465 			total += nbytes;
466 		vap->va_size = total;
467 	}
468 
469 #ifdef KERNFS_DIAGNOSTIC
470 	printf("kernfs_getattr: return error %d\n", error);
471 #endif
472 	return (error);
473 }
474 
475 /*ARGSUSED*/
476 int
477 kernfs_setattr(v)
478 	void *v;
479 {
480 	/*
481 	 * Silently ignore attribute changes.
482 	 * This allows for open with truncate to have no
483 	 * effect until some data is written.  I want to
484 	 * do it this way because all writes are atomic.
485 	 */
486 	return (0);
487 }
488 
489 int
490 kernfs_read(v)
491 	void *v;
492 {
493 	struct vop_read_args /* {
494 		struct vnode *a_vp;
495 		struct uio *a_uio;
496 		int  a_ioflag;
497 		struct ucred *a_cred;
498 	} */ *ap = v;
499 	struct vnode *vp = ap->a_vp;
500 	struct uio *uio = ap->a_uio;
501 	struct kern_target *kt;
502 	char strbuf[KSTRING], *buf;
503 	int off, len;
504 	int error;
505 
506 	if (vp->v_type == VDIR)
507 		return (EOPNOTSUPP);
508 
509 	kt = VTOKERN(vp)->kf_kt;
510 
511 #ifdef KERNFS_DIAGNOSTIC
512 	printf("kern_read %s\n", kt->kt_name);
513 #endif
514 
515 	off = uio->uio_offset;
516 #if 0
517 	while (buf = strbuf,
518 #else
519 	if (buf = strbuf,
520 #endif
521 	    len = kernfs_xread(kt, off, &buf, sizeof(strbuf))) {
522 		if ((error = uiomove(buf, len, uio)) != 0)
523 			return (error);
524 		off += len;
525 	}
526 	return (0);
527 }
528 
529 int
530 kernfs_write(v)
531 	void *v;
532 {
533 	struct vop_write_args /* {
534 		struct vnode *a_vp;
535 		struct uio *a_uio;
536 		int  a_ioflag;
537 		struct ucred *a_cred;
538 	} */ *ap = v;
539 	struct vnode *vp = ap->a_vp;
540 	struct uio *uio = ap->a_uio;
541 	struct kern_target *kt;
542 	int error, xlen;
543 	char strbuf[KSTRING];
544 
545 	if (vp->v_type == VDIR)
546 		return (EOPNOTSUPP);
547 
548 	kt = VTOKERN(vp)->kf_kt;
549 
550 	if (uio->uio_offset != 0)
551 		return (EINVAL);
552 
553 	xlen = min(uio->uio_resid, KSTRING-1);
554 	if ((error = uiomove(strbuf, xlen, uio)) != 0)
555 		return (error);
556 
557 	if (uio->uio_resid != 0)
558 		return (EIO);
559 
560 	strbuf[xlen] = '\0';
561 	xlen = strlen(strbuf);
562 	return (kernfs_xwrite(kt, strbuf, xlen));
563 }
564 
565 int
566 kernfs_readdir(v)
567 	void *v;
568 {
569 	struct vop_readdir_args /* {
570 		struct vnode *a_vp;
571 		struct uio *a_uio;
572 		struct ucred *a_cred;
573 		int *a_eofflag;
574 		u_long *a_cookies;
575 		int a_ncookies;
576 	} */ *ap = v;
577 	struct uio *uio = ap->a_uio;
578 	struct dirent d;
579 	struct kern_target *kt;
580 	int i;
581 	int error;
582 	u_long *cookies = ap->a_cookies;
583 	int ncookies = ap->a_ncookies;
584 
585 	if (ap->a_vp->v_type != VDIR)
586 		return (ENOTDIR);
587 
588 	if (uio->uio_resid < UIO_MX)
589 		return (EINVAL);
590 	if (uio->uio_offset < 0)
591 		return (EINVAL);
592 
593 	error = 0;
594 	i = uio->uio_offset;
595 	bzero((caddr_t)&d, UIO_MX);
596 	d.d_reclen = UIO_MX;
597 
598 	for (kt = &kern_targets[i];
599 	     uio->uio_resid >= UIO_MX && i < nkern_targets; kt++, i++) {
600 #ifdef KERNFS_DIAGNOSTIC
601 		printf("kernfs_readdir: i = %d\n", i);
602 #endif
603 
604 		if (kt->kt_tag == KTT_DEVICE) {
605 			dev_t *dp = kt->kt_data;
606 			struct vnode *fvp;
607 
608 			if (*dp == NODEV || !vfinddev(*dp, kt->kt_vtype, &fvp))
609 				continue;
610 		}
611 
612 		d.d_fileno = i + 3;
613 		d.d_namlen = kt->kt_namlen;
614 		bcopy(kt->kt_name, d.d_name, kt->kt_namlen + 1);
615 		d.d_type = kt->kt_type;
616 
617 		if ((error = uiomove((caddr_t)&d, UIO_MX, uio)) != 0)
618 			break;
619 		if (ncookies-- > 0)
620 			*cookies++ = i + 1;
621 	}
622 
623 	uio->uio_offset = i;
624 	return (error);
625 }
626 
627 int
628 kernfs_inactive(v)
629 	void *v;
630 {
631 	struct vop_inactive_args /* {
632 		struct vnode *a_vp;
633 	} */ *ap = v;
634 	struct vnode *vp = ap->a_vp;
635 
636 #ifdef KERNFS_DIAGNOSTIC
637 	printf("kernfs_inactive(%x)\n", vp);
638 #endif
639 	/*
640 	 * Clear out the v_type field to avoid
641 	 * nasty things happening in vgone().
642 	 */
643 	vp->v_type = VNON;
644 	return (0);
645 }
646 
647 int
648 kernfs_reclaim(v)
649 	void *v;
650 {
651 	struct vop_reclaim_args /* {
652 		struct vnode *a_vp;
653 	} */ *ap = v;
654 	struct vnode *vp = ap->a_vp;
655 
656 #ifdef KERNFS_DIAGNOSTIC
657 	printf("kernfs_reclaim(%x)\n", vp);
658 #endif
659 	if (vp->v_data) {
660 		FREE(vp->v_data, M_TEMP);
661 		vp->v_data = 0;
662 	}
663 	return (0);
664 }
665 
666 /*
667  * Return POSIX pathconf information applicable to special devices.
668  */
669 int
670 kernfs_pathconf(v)
671 	void *v;
672 {
673 	struct vop_pathconf_args /* {
674 		struct vnode *a_vp;
675 		int a_name;
676 		register_t *a_retval;
677 	} */ *ap = v;
678 
679 	switch (ap->a_name) {
680 	case _PC_LINK_MAX:
681 		*ap->a_retval = LINK_MAX;
682 		return (0);
683 	case _PC_MAX_CANON:
684 		*ap->a_retval = MAX_CANON;
685 		return (0);
686 	case _PC_MAX_INPUT:
687 		*ap->a_retval = MAX_INPUT;
688 		return (0);
689 	case _PC_PIPE_BUF:
690 		*ap->a_retval = PIPE_BUF;
691 		return (0);
692 	case _PC_CHOWN_RESTRICTED:
693 		*ap->a_retval = 1;
694 		return (0);
695 	case _PC_VDISABLE:
696 		*ap->a_retval = _POSIX_VDISABLE;
697 		return (0);
698 	default:
699 		return (EINVAL);
700 	}
701 	/* NOTREACHED */
702 }
703 
704 /*
705  * Print out the contents of a /dev/fd vnode.
706  */
707 /* ARGSUSED */
708 int
709 kernfs_print(v)
710 	void *v;
711 {
712 
713 	printf("tag VT_KERNFS, kernfs vnode\n");
714 	return (0);
715 }
716 
717 int
718 kernfs_link(v)
719 	void *v;
720 {
721 	struct vop_link_args /* {
722 		struct vnode *a_dvp;
723 		struct vnode *a_vp;
724 		struct componentname *a_cnp;
725 	} */ *ap = v;
726 
727 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
728 	vput(ap->a_dvp);
729 	return (EROFS);
730 }
731 
732 int
733 kernfs_symlink(v)
734 	void *v;
735 {
736 	struct vop_symlink_args /* {
737 		struct vnode *a_dvp;
738 		struct vnode **a_vpp;
739 		struct componentname *a_cnp;
740 		struct vattr *a_vap;
741 		char *a_target;
742 	} */ *ap = v;
743 
744 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
745 	vput(ap->a_dvp);
746 	return (EROFS);
747 }
748