xref: /netbsd-src/sys/miscfs/kernfs/kernfs_vnops.c (revision 1394f01b4a9e99092957ca5d824d67219565d9b5)
1 /*	$NetBSD: kernfs_vnops.c,v 1.50 1997/05/10 22:04:14 pk 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 kern_targets[] = {
73 /* NOTE: The name must be less than UIO_MX-16 chars in length */
74 #define N(s) sizeof(s)-1, s
75      /*        name            data          tag           type  ro/rw */
76      { DT_DIR, N("."),         0,            KTT_NULL,     VDIR, DIR_MODE   },
77      { DT_DIR, N(".."),        0,            KTT_NULL,     VDIR, DIR_MODE   },
78      { DT_REG, N("boottime"),  &boottime.tv_sec, KTT_INT,  VREG, READ_MODE  },
79      { DT_REG, N("copyright"), copyright,    KTT_STRING,   VREG, READ_MODE  },
80      { DT_REG, N("hostname"),  0,            KTT_HOSTNAME, VREG, WRITE_MODE },
81      { DT_REG, N("hz"),        &hz,          KTT_INT,      VREG, READ_MODE  },
82      { DT_REG, N("loadavg"),   0,            KTT_AVENRUN,  VREG, READ_MODE  },
83      { DT_REG, N("msgbuf"),    0,	     KTT_MSGBUF,   VREG, READ_MODE  },
84      { DT_REG, N("pagesize"),  &cnt.v_page_size, KTT_INT,  VREG, READ_MODE  },
85      { DT_REG, N("physmem"),   &physmem,     KTT_INT,      VREG, READ_MODE  },
86 #if 0
87      { DT_DIR, N("root"),      0,            KTT_NULL,     VDIR, DIR_MODE   },
88 #endif
89      { DT_BLK, N("rootdev"),   &rootdev,     KTT_DEVICE,   VBLK, READ_MODE  },
90      { DT_CHR, N("rrootdev"),  &rrootdev,    KTT_DEVICE,   VCHR, READ_MODE  },
91      { DT_REG, N("time"),      0,            KTT_TIME,     VREG, READ_MODE  },
92      { DT_REG, N("version"),   version,      KTT_STRING,   VREG, READ_MODE  },
93 #undef N
94 };
95 static int nkern_targets = sizeof(kern_targets) / sizeof(kern_targets[0]);
96 
97 int	kernfs_lookup	__P((void *));
98 #define	kernfs_create	genfs_eopnotsupp
99 #define	kernfs_mknod	genfs_eopnotsupp
100 #define	kernfs_open	genfs_nullop
101 #define	kernfs_close	genfs_nullop
102 int	kernfs_access	__P((void *));
103 int	kernfs_getattr	__P((void *));
104 int	kernfs_setattr	__P((void *));
105 int	kernfs_read	__P((void *));
106 int	kernfs_write	__P((void *));
107 #define	kernfs_ioctl	genfs_eopnotsupp
108 #define	kernfs_poll	genfs_poll
109 #define	kernfs_mmap	genfs_eopnotsupp
110 #define	kernfs_fsync	genfs_nullop
111 #define	kernfs_seek	genfs_nullop
112 #define	kernfs_remove	genfs_eopnotsupp
113 int	kernfs_link	__P((void *));
114 #define	kernfs_rename	genfs_eopnotsupp
115 #define	kernfs_mkdir	genfs_eopnotsupp
116 #define	kernfs_rmdir	genfs_eopnotsupp
117 int	kernfs_symlink	__P((void *));
118 int	kernfs_readdir	__P((void *));
119 #define	kernfs_readlink	genfs_eopnotsupp
120 #define	kernfs_abortop	genfs_abortop
121 int	kernfs_inactive	__P((void *));
122 int	kernfs_reclaim	__P((void *));
123 #define	kernfs_lock	genfs_nullop
124 #define	kernfs_unlock	genfs_nullop
125 #define	kernfs_bmap	genfs_badop
126 #define	kernfs_strategy	genfs_badop
127 int	kernfs_print	__P((void *));
128 #define	kernfs_islocked	genfs_nullop
129 int	kernfs_pathconf	__P((void *));
130 #define	kernfs_advlock	genfs_eopnotsupp
131 #define	kernfs_blkatoff	genfs_eopnotsupp
132 #define	kernfs_valloc	genfs_eopnotsupp
133 #define	kernfs_vfree	genfs_nullop
134 #define	kernfs_truncate	genfs_eopnotsupp
135 #define	kernfs_update	genfs_nullop
136 #define	kernfs_bwrite	genfs_eopnotsupp
137 
138 int	kernfs_xread __P((struct kern_target *, int, char **, int));
139 int	kernfs_xwrite __P((struct kern_target *, char *, int));
140 
141 int (**kernfs_vnodeop_p) __P((void *));
142 struct vnodeopv_entry_desc kernfs_vnodeop_entries[] = {
143 	{ &vop_default_desc, vn_default_error },
144 	{ &vop_lookup_desc, kernfs_lookup },		/* lookup */
145 	{ &vop_create_desc, kernfs_create },		/* create */
146 	{ &vop_mknod_desc, kernfs_mknod },		/* mknod */
147 	{ &vop_open_desc, kernfs_open },		/* open */
148 	{ &vop_close_desc, kernfs_close },		/* close */
149 	{ &vop_access_desc, kernfs_access },		/* access */
150 	{ &vop_getattr_desc, kernfs_getattr },		/* getattr */
151 	{ &vop_setattr_desc, kernfs_setattr },		/* setattr */
152 	{ &vop_read_desc, kernfs_read },		/* read */
153 	{ &vop_write_desc, kernfs_write },		/* write */
154 	{ &vop_ioctl_desc, kernfs_ioctl },		/* ioctl */
155 	{ &vop_poll_desc, kernfs_poll },		/* poll */
156 	{ &vop_mmap_desc, kernfs_mmap },		/* mmap */
157 	{ &vop_fsync_desc, kernfs_fsync },		/* fsync */
158 	{ &vop_seek_desc, kernfs_seek },		/* seek */
159 	{ &vop_remove_desc, kernfs_remove },		/* remove */
160 	{ &vop_link_desc, kernfs_link },		/* link */
161 	{ &vop_rename_desc, kernfs_rename },		/* rename */
162 	{ &vop_mkdir_desc, kernfs_mkdir },		/* mkdir */
163 	{ &vop_rmdir_desc, kernfs_rmdir },		/* rmdir */
164 	{ &vop_symlink_desc, kernfs_symlink },		/* symlink */
165 	{ &vop_readdir_desc, kernfs_readdir },		/* readdir */
166 	{ &vop_readlink_desc, kernfs_readlink },	/* readlink */
167 	{ &vop_abortop_desc, kernfs_abortop },		/* abortop */
168 	{ &vop_inactive_desc, kernfs_inactive },	/* inactive */
169 	{ &vop_reclaim_desc, kernfs_reclaim },		/* reclaim */
170 	{ &vop_lock_desc, kernfs_lock },		/* lock */
171 	{ &vop_unlock_desc, kernfs_unlock },		/* unlock */
172 	{ &vop_bmap_desc, kernfs_bmap },		/* bmap */
173 	{ &vop_strategy_desc, kernfs_strategy },	/* strategy */
174 	{ &vop_print_desc, kernfs_print },		/* print */
175 	{ &vop_islocked_desc, kernfs_islocked },	/* islocked */
176 	{ &vop_pathconf_desc, kernfs_pathconf },	/* pathconf */
177 	{ &vop_advlock_desc, kernfs_advlock },		/* advlock */
178 	{ &vop_blkatoff_desc, kernfs_blkatoff },	/* blkatoff */
179 	{ &vop_valloc_desc, kernfs_valloc },		/* valloc */
180 	{ &vop_vfree_desc, kernfs_vfree },		/* vfree */
181 	{ &vop_truncate_desc, kernfs_truncate },	/* truncate */
182 	{ &vop_update_desc, kernfs_update },		/* update */
183 	{ &vop_bwrite_desc, kernfs_bwrite },		/* bwrite */
184 	{ (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
185 };
186 struct vnodeopv_desc kernfs_vnodeop_opv_desc =
187 	{ &kernfs_vnodeop_p, kernfs_vnodeop_entries };
188 
189 int
190 kernfs_xread(kt, off, bufp, len)
191 	struct kern_target *kt;
192 	int off;
193 	char **bufp;
194 	int len;
195 {
196 
197 	switch (kt->kt_tag) {
198 	case KTT_TIME: {
199 		struct timeval tv;
200 
201 		microtime(&tv);
202 		sprintf(*bufp, "%ld %ld\n", tv.tv_sec, tv.tv_usec);
203 		break;
204 	}
205 
206 	case KTT_INT: {
207 		int *ip = kt->kt_data;
208 
209 		sprintf(*bufp, "%d\n", *ip);
210 		break;
211 	}
212 
213 	case KTT_STRING: {
214 		char *cp = kt->kt_data;
215 
216 		*bufp = cp;
217 		break;
218 	}
219 
220 	case KTT_MSGBUF: {
221 		extern struct msgbuf *msgbufp;
222 		long n;
223 
224 		if (off >= MSG_BSIZE)
225 			return (0);
226 		n = msgbufp->msg_bufx + off;
227 		if (n >= MSG_BSIZE)
228 			n -= MSG_BSIZE;
229 		len = min(MSG_BSIZE - n, MSG_BSIZE - off);
230 		*bufp = msgbufp->msg_bufc + n;
231 		return (len);
232 	}
233 
234 	case KTT_HOSTNAME: {
235 		char *cp = hostname;
236 		int xlen = hostnamelen;
237 
238 		if (xlen >= (len-2))
239 			return (EINVAL);
240 
241 		bcopy(cp, *bufp, xlen);
242 		(*bufp)[xlen] = '\n';
243 		(*bufp)[xlen+1] = '\0';
244 		break;
245 	}
246 
247 	case KTT_AVENRUN:
248 		averunnable.fscale = FSCALE;
249 		sprintf(*bufp, "%d %d %d %ld\n",
250 		    averunnable.ldavg[0], averunnable.ldavg[1],
251 		    averunnable.ldavg[2], averunnable.fscale);
252 		break;
253 
254 	default:
255 		return (0);
256 	}
257 
258 	len = strlen(*bufp);
259 	if (len <= off)
260 		return (0);
261 	*bufp += off;
262 	return (len - off);
263 }
264 
265 int
266 kernfs_xwrite(kt, buf, len)
267 	struct kern_target *kt;
268 	char *buf;
269 	int len;
270 {
271 
272 	switch (kt->kt_tag) {
273 	case KTT_HOSTNAME:
274 		if (buf[len-1] == '\n')
275 			--len;
276 		bcopy(buf, hostname, len);
277 		hostname[len] = '\0';
278 		hostnamelen = len;
279 		return (0);
280 
281 	default:
282 		return (EIO);
283 	}
284 }
285 
286 
287 /*
288  * vp is the current namei directory
289  * ndp is the name to locate in that directory...
290  */
291 int
292 kernfs_lookup(v)
293 	void *v;
294 {
295 	struct vop_lookup_args /* {
296 		struct vnode * a_dvp;
297 		struct vnode ** a_vpp;
298 		struct componentname * a_cnp;
299 	} */ *ap = v;
300 	struct componentname *cnp = ap->a_cnp;
301 	struct vnode **vpp = ap->a_vpp;
302 	struct vnode *dvp = ap->a_dvp;
303 	const char *pname = cnp->cn_nameptr;
304 	struct kern_target *kt;
305 	struct vnode *fvp;
306 	int error, i;
307 
308 #ifdef KERNFS_DIAGNOSTIC
309 	printf("kernfs_lookup(%x)\n", ap);
310 	printf("kernfs_lookup(dp = %x, vpp = %x, cnp = %x)\n", dvp, vpp, ap->a_cnp);
311 	printf("kernfs_lookup(%s)\n", pname);
312 #endif
313 
314 	*vpp = NULLVP;
315 
316 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
317 		return (EROFS);
318 
319 	if (cnp->cn_namelen == 1 && *pname == '.') {
320 		*vpp = dvp;
321 		VREF(dvp);
322 		/*VOP_LOCK(dvp);*/
323 		return (0);
324 	}
325 
326 #if 0
327 	if (cnp->cn_namelen == 4 && bcmp(pname, "root", 4) == 0) {
328 		*vpp = rootdir;
329 		VREF(rootdir);
330 		VOP_LOCK(rootdir);
331 		return (0);
332 	}
333 #endif
334 
335 	for (kt = kern_targets, i = 0; i < nkern_targets; kt++, i++) {
336 		if (cnp->cn_namelen == kt->kt_namlen &&
337 		    bcmp(kt->kt_name, pname, cnp->cn_namelen) == 0)
338 			goto found;
339 	}
340 
341 #ifdef KERNFS_DIAGNOSTIC
342 	printf("kernfs_lookup: i = %d, failed", i);
343 #endif
344 
345 	return (cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS);
346 
347 found:
348 	if (kt->kt_tag == KTT_DEVICE) {
349 		dev_t *dp = kt->kt_data;
350 	loop:
351 		if (*dp == NODEV || !vfinddev(*dp, kt->kt_vtype, &fvp))
352 			return (ENOENT);
353 		*vpp = fvp;
354 		if (vget(fvp, 1))
355 			goto loop;
356 		return (0);
357 	}
358 
359 #ifdef KERNFS_DIAGNOSTIC
360 	printf("kernfs_lookup: allocate new vnode\n");
361 #endif
362 	error = getnewvnode(VT_KERNFS, dvp->v_mount, kernfs_vnodeop_p, &fvp);
363 	if (error)
364 		return (error);
365 
366 	MALLOC(fvp->v_data, void *, sizeof(struct kernfs_node), M_TEMP,
367 	    M_WAITOK);
368 	VTOKERN(fvp)->kf_kt = kt;
369 	fvp->v_type = kt->kt_vtype;
370 	*vpp = fvp;
371 
372 #ifdef KERNFS_DIAGNOSTIC
373 	printf("kernfs_lookup: newvp = %x\n", fvp);
374 #endif
375 	return (0);
376 }
377 
378 int
379 kernfs_access(v)
380 	void *v;
381 {
382 	struct vop_access_args /* {
383 		struct vnode *a_vp;
384 		int a_mode;
385 		struct ucred *a_cred;
386 		struct proc *a_p;
387 	} */ *ap = v;
388 	struct vnode *vp = ap->a_vp;
389 	mode_t mode;
390 
391 	if (vp->v_flag & VROOT) {
392 		mode = DIR_MODE;
393 	} else {
394 		struct kern_target *kt = VTOKERN(vp)->kf_kt;
395 		mode = kt->kt_mode;
396 	}
397 
398 	return (vaccess(vp->v_type, mode, (uid_t)0, (gid_t)0, ap->a_mode,
399 	    ap->a_cred));
400 }
401 
402 int
403 kernfs_getattr(v)
404 	void *v;
405 {
406 	struct vop_getattr_args /* {
407 		struct vnode *a_vp;
408 		struct vattr *a_vap;
409 		struct ucred *a_cred;
410 		struct proc *a_p;
411 	} */ *ap = v;
412 	struct vnode *vp = ap->a_vp;
413 	struct vattr *vap = ap->a_vap;
414 	struct timeval tv;
415 	int error = 0;
416 	char strbuf[KSTRING], *buf;
417 
418 	bzero((caddr_t) vap, sizeof(*vap));
419 	vattr_null(vap);
420 	vap->va_uid = 0;
421 	vap->va_gid = 0;
422 	vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
423 	vap->va_size = 0;
424 	vap->va_blocksize = DEV_BSIZE;
425 	microtime(&tv);
426 	TIMEVAL_TO_TIMESPEC(&tv, &vap->va_atime);
427 	vap->va_mtime = vap->va_atime;
428 	vap->va_ctime = vap->va_ctime;
429 	vap->va_gen = 0;
430 	vap->va_flags = 0;
431 	vap->va_rdev = 0;
432 	vap->va_bytes = 0;
433 
434 	if (vp->v_flag & VROOT) {
435 #ifdef KERNFS_DIAGNOSTIC
436 		printf("kernfs_getattr: stat rootdir\n");
437 #endif
438 		vap->va_type = VDIR;
439 		vap->va_mode = DIR_MODE;
440 		vap->va_nlink = 2;
441 		vap->va_fileid = 2;
442 		vap->va_size = DEV_BSIZE;
443 	} else {
444 		struct kern_target *kt = VTOKERN(vp)->kf_kt;
445 		int nbytes, total;
446 #ifdef KERNFS_DIAGNOSTIC
447 		printf("kernfs_getattr: stat target %s\n", kt->kt_name);
448 #endif
449 		vap->va_type = kt->kt_vtype;
450 		vap->va_mode = kt->kt_mode;
451 		vap->va_nlink = 1;
452 		vap->va_fileid = 3 + (kt - kern_targets);
453 		total = 0;
454 		while (buf = strbuf,
455 		       nbytes = kernfs_xread(kt, total, &buf, sizeof(strbuf)))
456 			total += nbytes;
457 		vap->va_size = total;
458 	}
459 
460 #ifdef KERNFS_DIAGNOSTIC
461 	printf("kernfs_getattr: return error %d\n", error);
462 #endif
463 	return (error);
464 }
465 
466 /*ARGSUSED*/
467 int
468 kernfs_setattr(v)
469 	void *v;
470 {
471 	/*
472 	 * Silently ignore attribute changes.
473 	 * This allows for open with truncate to have no
474 	 * effect until some data is written.  I want to
475 	 * do it this way because all writes are atomic.
476 	 */
477 	return (0);
478 }
479 
480 int
481 kernfs_read(v)
482 	void *v;
483 {
484 	struct vop_read_args /* {
485 		struct vnode *a_vp;
486 		struct uio *a_uio;
487 		int  a_ioflag;
488 		struct ucred *a_cred;
489 	} */ *ap = v;
490 	struct vnode *vp = ap->a_vp;
491 	struct uio *uio = ap->a_uio;
492 	struct kern_target *kt;
493 	char strbuf[KSTRING], *buf;
494 	int off, len;
495 	int error;
496 
497 	if (vp->v_type == VDIR)
498 		return (EOPNOTSUPP);
499 
500 	kt = VTOKERN(vp)->kf_kt;
501 
502 #ifdef KERNFS_DIAGNOSTIC
503 	printf("kern_read %s\n", kt->kt_name);
504 #endif
505 
506 	off = uio->uio_offset;
507 #if 0
508 	while (buf = strbuf,
509 #else
510 	if (buf = strbuf,
511 #endif
512 	    len = kernfs_xread(kt, off, &buf, sizeof(strbuf))) {
513 		if ((error = uiomove(buf, len, uio)) != 0)
514 			return (error);
515 		off += len;
516 	}
517 	return (0);
518 }
519 
520 int
521 kernfs_write(v)
522 	void *v;
523 {
524 	struct vop_write_args /* {
525 		struct vnode *a_vp;
526 		struct uio *a_uio;
527 		int  a_ioflag;
528 		struct ucred *a_cred;
529 	} */ *ap = v;
530 	struct vnode *vp = ap->a_vp;
531 	struct uio *uio = ap->a_uio;
532 	struct kern_target *kt;
533 	int error, xlen;
534 	char strbuf[KSTRING];
535 
536 	if (vp->v_type == VDIR)
537 		return (EOPNOTSUPP);
538 
539 	kt = VTOKERN(vp)->kf_kt;
540 
541 	if (uio->uio_offset != 0)
542 		return (EINVAL);
543 
544 	xlen = min(uio->uio_resid, KSTRING-1);
545 	if ((error = uiomove(strbuf, xlen, uio)) != 0)
546 		return (error);
547 
548 	if (uio->uio_resid != 0)
549 		return (EIO);
550 
551 	strbuf[xlen] = '\0';
552 	xlen = strlen(strbuf);
553 	return (kernfs_xwrite(kt, strbuf, xlen));
554 }
555 
556 int
557 kernfs_readdir(v)
558 	void *v;
559 {
560 	struct vop_readdir_args /* {
561 		struct vnode *a_vp;
562 		struct uio *a_uio;
563 		struct ucred *a_cred;
564 		int *a_eofflag;
565 		u_long *a_cookies;
566 		int a_ncookies;
567 	} */ *ap = v;
568 	struct uio *uio = ap->a_uio;
569 	struct dirent d;
570 	struct kern_target *kt;
571 	int i;
572 	int error;
573 	u_long *cookies = ap->a_cookies;
574 	int ncookies = ap->a_ncookies;
575 
576 	if (ap->a_vp->v_type != VDIR)
577 		return (ENOTDIR);
578 
579 	if (uio->uio_resid < UIO_MX)
580 		return (EINVAL);
581 	if (uio->uio_offset < 0)
582 		return (EINVAL);
583 
584 	error = 0;
585 	i = uio->uio_offset;
586 	bzero((caddr_t)&d, UIO_MX);
587 	d.d_reclen = UIO_MX;
588 
589 	for (kt = &kern_targets[i];
590 	     uio->uio_resid >= UIO_MX && i < nkern_targets; kt++, i++) {
591 #ifdef KERNFS_DIAGNOSTIC
592 		printf("kernfs_readdir: i = %d\n", i);
593 #endif
594 
595 		if (kt->kt_tag == KTT_DEVICE) {
596 			dev_t *dp = kt->kt_data;
597 			struct vnode *fvp;
598 
599 			if (*dp == NODEV || !vfinddev(*dp, kt->kt_vtype, &fvp))
600 				continue;
601 		}
602 
603 		d.d_fileno = i + 3;
604 		d.d_namlen = kt->kt_namlen;
605 		bcopy(kt->kt_name, d.d_name, kt->kt_namlen + 1);
606 		d.d_type = kt->kt_type;
607 
608 		if ((error = uiomove((caddr_t)&d, UIO_MX, uio)) != 0)
609 			break;
610 		if (ncookies-- > 0)
611 			*cookies++ = i + 1;
612 	}
613 
614 	uio->uio_offset = i;
615 	return (error);
616 }
617 
618 int
619 kernfs_inactive(v)
620 	void *v;
621 {
622 	struct vop_inactive_args /* {
623 		struct vnode *a_vp;
624 	} */ *ap = v;
625 	struct vnode *vp = ap->a_vp;
626 
627 #ifdef KERNFS_DIAGNOSTIC
628 	printf("kernfs_inactive(%x)\n", vp);
629 #endif
630 	/*
631 	 * Clear out the v_type field to avoid
632 	 * nasty things happening in vgone().
633 	 */
634 	vp->v_type = VNON;
635 	return (0);
636 }
637 
638 int
639 kernfs_reclaim(v)
640 	void *v;
641 {
642 	struct vop_reclaim_args /* {
643 		struct vnode *a_vp;
644 	} */ *ap = v;
645 	struct vnode *vp = ap->a_vp;
646 
647 #ifdef KERNFS_DIAGNOSTIC
648 	printf("kernfs_reclaim(%x)\n", vp);
649 #endif
650 	if (vp->v_data) {
651 		FREE(vp->v_data, M_TEMP);
652 		vp->v_data = 0;
653 	}
654 	return (0);
655 }
656 
657 /*
658  * Return POSIX pathconf information applicable to special devices.
659  */
660 int
661 kernfs_pathconf(v)
662 	void *v;
663 {
664 	struct vop_pathconf_args /* {
665 		struct vnode *a_vp;
666 		int a_name;
667 		register_t *a_retval;
668 	} */ *ap = v;
669 
670 	switch (ap->a_name) {
671 	case _PC_LINK_MAX:
672 		*ap->a_retval = LINK_MAX;
673 		return (0);
674 	case _PC_MAX_CANON:
675 		*ap->a_retval = MAX_CANON;
676 		return (0);
677 	case _PC_MAX_INPUT:
678 		*ap->a_retval = MAX_INPUT;
679 		return (0);
680 	case _PC_PIPE_BUF:
681 		*ap->a_retval = PIPE_BUF;
682 		return (0);
683 	case _PC_CHOWN_RESTRICTED:
684 		*ap->a_retval = 1;
685 		return (0);
686 	case _PC_VDISABLE:
687 		*ap->a_retval = _POSIX_VDISABLE;
688 		return (0);
689 	default:
690 		return (EINVAL);
691 	}
692 	/* NOTREACHED */
693 }
694 
695 /*
696  * Print out the contents of a /dev/fd vnode.
697  */
698 /* ARGSUSED */
699 int
700 kernfs_print(v)
701 	void *v;
702 {
703 
704 	printf("tag VT_KERNFS, kernfs vnode\n");
705 	return (0);
706 }
707 
708 int
709 kernfs_link(v)
710 	void *v;
711 {
712 	struct vop_link_args /* {
713 		struct vnode *a_dvp;
714 		struct vnode *a_vp;
715 		struct componentname *a_cnp;
716 	} */ *ap = v;
717 
718 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
719 	vput(ap->a_dvp);
720 	return (EROFS);
721 }
722 
723 int
724 kernfs_symlink(v)
725 	void *v;
726 {
727 	struct vop_symlink_args /* {
728 		struct vnode *a_dvp;
729 		struct vnode **a_vpp;
730 		struct componentname *a_cnp;
731 		struct vattr *a_vap;
732 		char *a_target;
733 	} */ *ap = v;
734 
735 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
736 	vput(ap->a_dvp);
737 	return (EROFS);
738 }
739