xref: /netbsd-src/sys/kern/kern_sysctl.c (revision 7330f729ccf0bd976a06f95fad452fe774fc7fd1)
1 /*	$NetBSD: kern_sysctl.c,v 1.264 2019/07/03 17:31:32 maxv Exp $	*/
2 
3 /*-
4  * Copyright (c) 2003, 2007, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Andrew Brown.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*-
33  * Copyright (c) 1982, 1986, 1989, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * This code is derived from software contributed to Berkeley by
37  * Mike Karels at Berkeley Software Design, Inc.
38  *
39  * Redistribution and use in source and binary forms, with or without
40  * modification, are permitted provided that the following conditions
41  * are met:
42  * 1. Redistributions of source code must retain the above copyright
43  *    notice, this list of conditions and the following disclaimer.
44  * 2. Redistributions in binary form must reproduce the above copyright
45  *    notice, this list of conditions and the following disclaimer in the
46  *    documentation and/or other materials provided with the distribution.
47  * 3. Neither the name of the University nor the names of its contributors
48  *    may be used to endorse or promote products derived from this software
49  *    without specific prior written permission.
50  *
51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
61  * SUCH DAMAGE.
62  *
63  *	@(#)kern_sysctl.c	8.9 (Berkeley) 5/20/95
64  */
65 
66 /*
67  * sysctl system call.
68  */
69 
70 #include <sys/cdefs.h>
71 __KERNEL_RCSID(0, "$NetBSD: kern_sysctl.c,v 1.264 2019/07/03 17:31:32 maxv Exp $");
72 
73 #ifdef _KERNEL_OPT
74 #include "opt_defcorename.h"
75 #endif
76 
77 #include "ksyms.h"
78 
79 #include <sys/param.h>
80 #define __COMPAT_SYSCTL
81 #include <sys/sysctl.h>
82 #include <sys/systm.h>
83 #include <sys/buf.h>
84 #include <sys/ksyms.h>
85 #include <sys/malloc.h>
86 #include <sys/mount.h>
87 #include <sys/syscallargs.h>
88 #include <sys/kauth.h>
89 #include <sys/ktrace.h>
90 #include <sys/rndsource.h>
91 
92 #define	MAXDESCLEN	1024
93 MALLOC_DEFINE(M_SYSCTLNODE, "sysctlnode", "sysctl node structures");
94 MALLOC_DEFINE(M_SYSCTLDATA, "sysctldata", "misc sysctl data");
95 
96 static int sysctl_mmap(SYSCTLFN_PROTO);
97 static int sysctl_alloc(struct sysctlnode *, int);
98 static int sysctl_realloc(struct sysctlnode *);
99 
100 static int sysctl_cvt_in(struct lwp *, int *, const void *, size_t,
101 			 struct sysctlnode *);
102 static int sysctl_cvt_out(struct lwp *, int, const struct sysctlnode *,
103 			  void *, size_t, size_t *);
104 
105 static int sysctl_log_add(struct sysctllog **, const struct sysctlnode *);
106 static int sysctl_log_realloc(struct sysctllog *);
107 
108 typedef void sysctl_setup_func(struct sysctllog **);
109 
110 #ifdef SYSCTL_DEBUG
111 #define DPRINTF(a)	printf a
112 #else
113 #define DPRINTF(a)
114 #endif
115 
116 struct sysctllog {
117 	const struct sysctlnode *log_root;
118 	int *log_num;
119 	int log_size, log_left;
120 };
121 
122 /*
123  * the "root" of the new sysctl tree
124  */
125 struct sysctlnode sysctl_root = {
126 	.sysctl_flags = SYSCTL_VERSION|
127 	    CTLFLAG_ROOT|CTLFLAG_READWRITE|
128 	    CTLTYPE_NODE,
129 	.sysctl_num = 0,
130 	.sysctl_size = sizeof(struct sysctlnode),
131 	.sysctl_name = "(root)",
132 };
133 
134 /*
135  * link set of functions that add nodes at boot time (see also
136  * sysctl_buildtree())
137  */
138 __link_set_decl(sysctl_funcs, sysctl_setup_func);
139 
140 /*
141  * The `sysctl_treelock' is intended to serialize access to the sysctl
142  * tree.  XXX This has serious problems; allocating memory and
143  * copying data out with the lock held is insane.
144  */
145 krwlock_t sysctl_treelock;
146 
147 kmutex_t sysctl_file_marker_lock;
148 
149 /*
150  * Attributes stored in the kernel.
151  */
152 char hostname[MAXHOSTNAMELEN];
153 int hostnamelen;
154 
155 char domainname[MAXHOSTNAMELEN];
156 int domainnamelen;
157 
158 long hostid;
159 
160 #ifndef DEFCORENAME
161 #define	DEFCORENAME	"%n.core"
162 #endif
163 char defcorename[MAXPATHLEN] = DEFCORENAME;
164 
165 /*
166  * ********************************************************************
167  * Section 0: Some simple glue
168  * ********************************************************************
169  * By wrapping copyin(), copyout(), and copyinstr() like this, we can
170  * stop caring about who's calling us and simplify some code a bunch.
171  * ********************************************************************
172  */
173 int
174 sysctl_copyin(struct lwp *l, const void *uaddr, void *kaddr, size_t len)
175 {
176 	int error;
177 
178 	if (l != NULL) {
179 		error = copyin(uaddr, kaddr, len);
180 		ktrmibio(-1, UIO_WRITE, uaddr, len, error);
181 	} else {
182 		error = kcopy(uaddr, kaddr, len);
183 	}
184 
185 	return error;
186 }
187 
188 int
189 sysctl_copyout(struct lwp *l, const void *kaddr, void *uaddr, size_t len)
190 {
191 	int error;
192 
193 	if (l != NULL) {
194 		error = copyout(kaddr, uaddr, len);
195 		ktrmibio(-1, UIO_READ, uaddr, len, error);
196 	} else {
197 		error = kcopy(kaddr, uaddr, len);
198 	}
199 
200 	return error;
201 }
202 
203 int
204 sysctl_copyinstr(struct lwp *l, const void *uaddr, void *kaddr,
205 		 size_t len, size_t *done)
206 {
207 	int error;
208 
209 	if (l != NULL) {
210 		error = copyinstr(uaddr, kaddr, len, done);
211 		ktrmibio(-1, UIO_WRITE, uaddr, len, error);
212 	} else {
213 		error = copystr(uaddr, kaddr, len, done);
214 	}
215 
216 	return error;
217 }
218 
219 /*
220  * ********************************************************************
221  * Initialize sysctl subsystem.
222  * ********************************************************************
223  */
224 void
225 sysctl_init(void)
226 {
227 	sysctl_setup_func *const *sysctl_setup;
228 
229 	rw_init(&sysctl_treelock);
230 
231 	/*
232 	 * dynamic mib numbers start here
233 	 */
234 	sysctl_root.sysctl_num = CREATE_BASE;
235 	sysctl_basenode_init();
236 
237         __link_set_foreach(sysctl_setup, sysctl_funcs) {
238 		(**sysctl_setup)(NULL);
239 	}
240 
241 	mutex_init(&sysctl_file_marker_lock, MUTEX_DEFAULT, IPL_NONE);
242 }
243 
244 /*
245  * Setting this means no more permanent nodes can be added,
246  * trees that claim to be readonly at the root now are, and if
247  * the main tree is readonly, *everything* is.
248  *
249  * Also starts up the PRNG used for the "random" sysctl: it's
250  * better to start it later than sooner.
251  *
252  * Call this at the end of kernel init.
253  */
254 void
255 sysctl_finalize(void)
256 {
257 
258 	sysctl_root.sysctl_flags |= CTLFLAG_PERMANENT;
259 }
260 
261 /*
262  * ********************************************************************
263  * The main native sysctl system call itself.
264  * ********************************************************************
265  */
266 int
267 sys___sysctl(struct lwp *l, const struct sys___sysctl_args *uap, register_t *retval)
268 {
269 	/* {
270 		syscallarg(const int *) name;
271 		syscallarg(u_int) namelen;
272 		syscallarg(void *) old;
273 		syscallarg(size_t *) oldlenp;
274 		syscallarg(const void *) new;
275 		syscallarg(size_t) newlen;
276 	} */
277 	int error, nerror, name[CTL_MAXNAME];
278 	size_t oldlen, savelen, *oldlenp;
279 
280 	/*
281 	 * get oldlen
282 	 */
283 	oldlen = 0;
284 	oldlenp = SCARG(uap, oldlenp);
285 	if (oldlenp != NULL) {
286 		error = copyin(oldlenp, &oldlen, sizeof(oldlen));
287 		if (error)
288 			return (error);
289 	}
290 	savelen = oldlen;
291 
292 	/*
293 	 * top-level sysctl names may or may not be non-terminal, but
294 	 * we don't care
295 	 */
296 	if (SCARG(uap, namelen) > CTL_MAXNAME || SCARG(uap, namelen) < 1)
297 		return (EINVAL);
298 	error = copyin(SCARG(uap, name), &name,
299 		       SCARG(uap, namelen) * sizeof(int));
300 	if (error)
301 		return (error);
302 
303 	ktrmib(name, SCARG(uap, namelen));
304 
305 	sysctl_lock(SCARG(uap, newv) != NULL);
306 
307 	/*
308 	 * do sysctl work (NULL means main built-in default tree)
309 	 */
310 	error = sysctl_dispatch(&name[0], SCARG(uap, namelen),
311 				SCARG(uap, oldv), &oldlen,
312 				SCARG(uap, newv), SCARG(uap, newlen),
313 				&name[0], l, NULL);
314 
315 	/*
316 	 * release the sysctl lock
317 	 */
318 	sysctl_unlock();
319 
320 	/*
321 	 * set caller's oldlen to new value even in the face of an
322 	 * error (if this gets an error and they didn't have one, they
323 	 * get this one)
324 	 */
325 	if (oldlenp) {
326 		nerror = copyout(&oldlen, oldlenp, sizeof(oldlen));
327 		if (error == 0)
328 			error = nerror;
329 	}
330 
331 	/*
332 	 * if the only problem is that we weren't given enough space,
333 	 * that's an ENOMEM error
334 	 */
335 	if (error == 0 && SCARG(uap, oldv) != NULL && savelen < oldlen)
336 		error = ENOMEM;
337 
338 	return (error);
339 }
340 
341 /*
342  * ********************************************************************
343  * Section 1: How the tree is used
344  * ********************************************************************
345  * Implementations of sysctl for emulations should typically need only
346  * these three functions in this order: lock the tree, dispatch
347  * request into it, unlock the tree.
348  * ********************************************************************
349  */
350 void
351 sysctl_lock(bool write)
352 {
353 
354 	if (write) {
355 		rw_enter(&sysctl_treelock, RW_WRITER);
356 		curlwp->l_pflag |= LP_SYSCTLWRITE;
357 	} else {
358 		rw_enter(&sysctl_treelock, RW_READER);
359 		curlwp->l_pflag &= ~LP_SYSCTLWRITE;
360 	}
361 }
362 
363 void
364 sysctl_relock(void)
365 {
366 
367 	if ((curlwp->l_pflag & LP_SYSCTLWRITE) != 0) {
368 		rw_enter(&sysctl_treelock, RW_WRITER);
369 	} else {
370 		rw_enter(&sysctl_treelock, RW_READER);
371 	}
372 }
373 
374 /*
375  * ********************************************************************
376  * the main sysctl dispatch routine.  scans the given tree and picks a
377  * function to call based on what it finds.
378  * ********************************************************************
379  */
380 int
381 sysctl_dispatch(SYSCTLFN_ARGS)
382 {
383 	int error;
384 	sysctlfn fn;
385 	int ni;
386 
387 	KASSERT(rw_lock_held(&sysctl_treelock));
388 
389 	if (rnode && SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
390 		printf("sysctl_dispatch: rnode %p wrong version\n", rnode);
391 		error = EINVAL;
392 		goto out;
393 	}
394 
395 	fn = NULL;
396 	error = sysctl_locate(l, name, namelen, &rnode, &ni);
397 
398 	if (rnode->sysctl_func != NULL) {
399 		/*
400 		 * the node we ended up at has a function, so call it.  it can
401 		 * hand off to query or create if it wants to.
402 		 */
403 		fn = rnode->sysctl_func;
404 	} else if (error == 0) {
405 		/*
406 		 * we found the node they were looking for, so do a lookup.
407 		 */
408 		fn = (sysctlfn)sysctl_lookup; /* XXX may write to rnode */
409 	} else if (error == ENOENT && (ni + 1) == namelen && name[ni] < 0) {
410 		/*
411 		 * prospective parent node found, but the terminal node was
412 		 * not.  generic operations associate with the parent.
413 		 */
414 		switch (name[ni]) {
415 		case CTL_QUERY:
416 			fn = sysctl_query;
417 			break;
418 		case CTL_CREATE:
419 #if NKSYMS > 0
420 		case CTL_CREATESYM:
421 #endif /* NKSYMS > 0 */
422 			if (newp == NULL) {
423 				error = EINVAL;
424 				break;
425 			}
426 			KASSERT(rw_write_held(&sysctl_treelock));
427 			fn = (sysctlfn)sysctl_create; /* we own the rnode */
428 			break;
429 		case CTL_DESTROY:
430 			if (newp == NULL) {
431 				error = EINVAL;
432 				break;
433 			}
434 			KASSERT(rw_write_held(&sysctl_treelock));
435 			fn = (sysctlfn)sysctl_destroy; /* we own the rnode */
436 			break;
437 		case CTL_MMAP:
438 			fn = (sysctlfn)sysctl_mmap; /* we own the rnode */
439 			break;
440 		case CTL_DESCRIBE:
441 			fn = sysctl_describe;
442 			break;
443 		default:
444 			error = EOPNOTSUPP;
445 			break;
446 		}
447 	}
448 
449 	/*
450 	 * after all of that, maybe we found someone who knows how to
451 	 * get us what we want?
452 	 */
453 	if (fn != NULL)
454 		error = (*fn)(name + ni, namelen - ni, oldp, oldlenp,
455 			      newp, newlen, name, l, rnode);
456 	else if (error == 0)
457 		error = EOPNOTSUPP;
458 
459 out:
460 	return (error);
461 }
462 
463 /*
464  * ********************************************************************
465  * Releases the tree lock.
466  * ********************************************************************
467  */
468 void
469 sysctl_unlock(void)
470 {
471 
472 	rw_exit(&sysctl_treelock);
473 }
474 
475 /*
476  * ********************************************************************
477  * Section 2: The main tree interfaces
478  * ********************************************************************
479  * This is how sysctl_dispatch() does its work, and you can too, by
480  * calling these routines from helpers (though typically only
481  * sysctl_lookup() will be used).  The tree MUST BE LOCKED when these
482  * are called.
483  * ********************************************************************
484  */
485 
486 /*
487  * sysctl_locate -- Finds the node matching the given mib under the
488  * given tree (via rv).  If no tree is given, we fall back to the
489  * native tree.  The current process (via l) is used for access
490  * control on the tree (some nodes may be traversable only by root) and
491  * on return, nip will show how many numbers in the mib were consumed.
492  */
493 int
494 sysctl_locate(struct lwp *l, const int *name, u_int namelen,
495 	      const struct sysctlnode **rnode, int *nip)
496 {
497 	const struct sysctlnode *node, *pnode;
498 	int tn, si, ni, error, alias;
499 
500 	KASSERT(rw_lock_held(&sysctl_treelock));
501 
502 	/*
503 	 * basic checks and setup
504 	 */
505 	if (*rnode == NULL)
506 		*rnode = &sysctl_root;
507 	if (nip)
508 		*nip = 0;
509 	if (namelen == 0)
510 		return (0);
511 
512 	/*
513 	 * search starts from "root"
514 	 */
515 	pnode = *rnode;
516 	if (SYSCTL_VERS(pnode->sysctl_flags) != SYSCTL_VERSION) {
517 		printf("sysctl_locate: pnode %p wrong version\n", pnode);
518 		return (EINVAL);
519 	}
520 	node = pnode->sysctl_child;
521 	error = 0;
522 
523 	/*
524 	 * scan for node to which new node should be attached
525 	 */
526 	for (ni = 0; ni < namelen; ni++) {
527 		/*
528 		 * walked off bottom of tree
529 		 */
530 		if (node == NULL) {
531 			if (SYSCTL_TYPE(pnode->sysctl_flags) == CTLTYPE_NODE)
532 				error = ENOENT;
533 			else
534 				error = ENOTDIR;
535 			break;
536 		}
537 		/*
538 		 * can anyone traverse this node or only root?
539 		 */
540 		if (l != NULL && (pnode->sysctl_flags & CTLFLAG_PRIVATE) &&
541 		    (error = kauth_authorize_system(l->l_cred,
542 		    KAUTH_SYSTEM_SYSCTL, KAUTH_REQ_SYSTEM_SYSCTL_PRVT,
543 		    NULL, NULL, NULL)) != 0)
544 			return (error);
545 		/*
546 		 * find a child node with the right number
547 		 */
548 		tn = name[ni];
549 		alias = 0;
550 
551 		si = 0;
552 		/*
553 		 * Note: ANYNUMBER only matches positive integers.
554 		 * Since ANYNUMBER is only permitted on single-node
555 		 * sub-trees (eg proc), check before the loop and skip
556 		 * it if we can.
557 		 */
558 		if ((node[si].sysctl_flags & CTLFLAG_ANYNUMBER) && (tn >= 0))
559 			goto foundit;
560 		for (; si < pnode->sysctl_clen; si++) {
561 			if (node[si].sysctl_num == tn) {
562 				if (node[si].sysctl_flags & CTLFLAG_ALIAS) {
563 					if (alias++ == 4)
564 						break;
565 					else {
566 						tn = node[si].sysctl_alias;
567 						si = -1;
568 					}
569 				} else
570 					goto foundit;
571 			}
572 		}
573 		/*
574 		 * if we ran off the end, it obviously doesn't exist
575 		 */
576 		error = ENOENT;
577 		break;
578 
579 		/*
580 		 * so far so good, move on down the line
581 		 */
582 	  foundit:
583 		pnode = &node[si];
584 		if (SYSCTL_TYPE(pnode->sysctl_flags) == CTLTYPE_NODE)
585 			node = node[si].sysctl_child;
586 		else
587 			node = NULL;
588 	}
589 
590 	*rnode = pnode;
591 	if (nip)
592 		*nip = ni;
593 
594 	return (error);
595 }
596 
597 /*
598  * sysctl_query -- The auto-discovery engine.  Copies out the structs
599  * describing nodes under the given node and handles overlay trees.
600  */
601 int
602 sysctl_query(SYSCTLFN_ARGS)
603 {
604 	int error, ni, elim, v;
605 	size_t out, left, t;
606 	const struct sysctlnode *enode, *onode;
607 	struct sysctlnode qnode;
608 
609 	KASSERT(rw_lock_held(&sysctl_treelock));
610 
611 	if (SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
612 		printf("sysctl_query: rnode %p wrong version\n", rnode);
613 		return (EINVAL);
614 	}
615 
616 	if (SYSCTL_TYPE(rnode->sysctl_flags) != CTLTYPE_NODE)
617 		return (ENOTDIR);
618 	if (namelen != 1 || name[0] != CTL_QUERY)
619 		return (EINVAL);
620 
621 	error = 0;
622 	out = 0;
623 	left = *oldlenp;
624 	elim = 0;
625 	enode = NULL;
626 
627 	/*
628 	 * translate the given request to a current node
629 	 */
630 	error = sysctl_cvt_in(l, &v, newp, newlen, &qnode);
631 	if (error)
632 		return (error);
633 
634 	/*
635 	 * if the request specifies a version, check it
636 	 */
637 	if (qnode.sysctl_ver != 0) {
638 		enode = rnode;
639 		if (qnode.sysctl_ver != enode->sysctl_ver &&
640 		    qnode.sysctl_ver != sysctl_rootof(enode)->sysctl_ver)
641 			return (EINVAL);
642 	}
643 
644 	/*
645 	 * process has overlay tree
646 	 */
647 	if (l && l->l_proc->p_emul->e_sysctlovly) {
648 		enode = l->l_proc->p_emul->e_sysctlovly;
649 		elim = (name - oname);
650 		error = sysctl_locate(l, oname, elim, &enode, NULL);
651 		if (error == 0) {
652 			/* ah, found parent in overlay */
653 			elim = enode->sysctl_clen;
654 			enode = enode->sysctl_child;
655 		} else {
656 			error = 0;
657 			elim = 0;
658 			enode = NULL;
659 		}
660 	}
661 
662 	for (ni = 0; ni < rnode->sysctl_clen; ni++) {
663 		onode = &rnode->sysctl_child[ni];
664 		if (enode && enode->sysctl_num == onode->sysctl_num) {
665 			if (SYSCTL_TYPE(enode->sysctl_flags) != CTLTYPE_NODE)
666 				onode = enode;
667 			if (--elim > 0)
668 				enode++;
669 			else
670 				enode = NULL;
671 		}
672 		error = sysctl_cvt_out(l, v, onode, oldp, left, &t);
673 		if (error)
674 			return (error);
675 		if (oldp != NULL)
676 			oldp = (char*)oldp + t;
677 		out += t;
678 		left -= MIN(left, t);
679 	}
680 
681 	/*
682 	 * overlay trees *MUST* be entirely consumed
683 	 */
684 	KASSERT(enode == NULL);
685 
686 	*oldlenp = out;
687 
688 	return (error);
689 }
690 
691 /*
692  * sysctl_create -- Adds a node (the description of which is taken
693  * from newp) to the tree, returning a copy of it in the space pointed
694  * to by oldp.  In the event that the requested slot is already taken
695  * (either by name or by number), the offending node is returned
696  * instead.  Yes, this is complex, but we want to make sure everything
697  * is proper.
698  */
699 #ifdef SYSCTL_DEBUG_CREATE
700 int _sysctl_create(SYSCTLFN_ARGS);
701 int
702 _sysctl_create(SYSCTLFN_ARGS)
703 #else
704 int
705 sysctl_create(SYSCTLFN_ARGS)
706 #endif
707 {
708 	struct sysctlnode nnode, *node, *pnode;
709 	int error, ni, at, nm, type, nsz, sz, flags, anum, v;
710 	void *own;
711 
712 	KASSERT(rw_write_held(&sysctl_treelock));
713 
714 	error = 0;
715 	own = NULL;
716 	anum = -1;
717 
718 	if (SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
719 		printf("sysctl_create: rnode %p wrong version\n", rnode);
720 		return (EINVAL);
721 	}
722 
723 	if (namelen != 1 || (name[namelen - 1] != CTL_CREATE
724 #if NKSYMS > 0
725 			     && name[namelen - 1] != CTL_CREATESYM
726 #endif /* NKSYMS > 0 */
727 			     ))
728 		return (EINVAL);
729 
730 	/*
731 	 * processes can only add nodes at securelevel 0, must be
732 	 * root, and can't add nodes to a parent that's not writeable
733 	 */
734 	if (l != NULL) {
735 #ifndef SYSCTL_DISALLOW_CREATE
736 		error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SYSCTL,
737 		    KAUTH_REQ_SYSTEM_SYSCTL_ADD, NULL, NULL, NULL);
738 		if (error)
739 			return (error);
740 		if (!(rnode->sysctl_flags & CTLFLAG_READWRITE))
741 #endif /* SYSCTL_DISALLOW_CREATE */
742 			return (EPERM);
743 	}
744 
745 	/*
746 	 * nothing can add a node if:
747 	 * we've finished initial set up of this tree and
748 	 * (the tree itself is not writeable or
749 	 * the entire sysctl system is not writeable)
750 	 */
751 	if ((sysctl_rootof(rnode)->sysctl_flags & CTLFLAG_PERMANENT) &&
752 	    (!(sysctl_rootof(rnode)->sysctl_flags & CTLFLAG_READWRITE) ||
753 	     !(sysctl_root.sysctl_flags & CTLFLAG_READWRITE)))
754 		return (EPERM);
755 
756 	/*
757 	 * it must be a "node", not a "int" or something
758 	 */
759 	if (SYSCTL_TYPE(rnode->sysctl_flags) != CTLTYPE_NODE)
760 		return (ENOTDIR);
761 	if (rnode->sysctl_flags & CTLFLAG_ALIAS) {
762 		printf("sysctl_create: attempt to add node to aliased "
763 		       "node %p\n", rnode);
764 		return (EINVAL);
765 	}
766 	pnode = __UNCONST(rnode); /* we are adding children to this node */
767 
768 	if (newp == NULL)
769 		return (EINVAL);
770 	error = sysctl_cvt_in(l, &v, newp, newlen, &nnode);
771 	if (error)
772 		return (error);
773 
774 	/*
775 	 * nodes passed in don't *have* parents
776 	 */
777 	if (nnode.sysctl_parent != NULL)
778 		return (EINVAL);
779 
780 	/*
781 	 * if we are indeed adding it, it should be a "good" name and
782 	 * number
783 	 */
784 	nm = nnode.sysctl_num;
785 #if NKSYMS > 0
786 	if (nm == CTL_CREATESYM)
787 		nm = CTL_CREATE;
788 #endif /* NKSYMS > 0 */
789 	if (nm < 0 && nm != CTL_CREATE)
790 		return (EINVAL);
791 
792 	/*
793 	 * the name can't start with a digit
794 	 */
795 	if (nnode.sysctl_name[0] >= '0' &&
796 	    nnode.sysctl_name[0] <= '9')
797 		return (EINVAL);
798 
799 	/*
800 	 * the name must be only alphanumerics or - or _, longer than
801 	 * 0 bytes and less than SYSCTL_NAMELEN
802 	 */
803 	nsz = 0;
804 	while (nsz < SYSCTL_NAMELEN && nnode.sysctl_name[nsz] != '\0') {
805 		if ((nnode.sysctl_name[nsz] >= '0' &&
806 		     nnode.sysctl_name[nsz] <= '9') ||
807 		    (nnode.sysctl_name[nsz] >= 'A' &&
808 		     nnode.sysctl_name[nsz] <= 'Z') ||
809 		    (nnode.sysctl_name[nsz] >= 'a' &&
810 		     nnode.sysctl_name[nsz] <= 'z') ||
811 		    nnode.sysctl_name[nsz] == '-' ||
812 		    nnode.sysctl_name[nsz] == '_')
813 			nsz++;
814 		else
815 			return (EINVAL);
816 	}
817 	if (nsz == 0 || nsz == SYSCTL_NAMELEN)
818 		return (EINVAL);
819 
820 	/*
821 	 * various checks revolve around size vs type, etc
822 	 */
823 	type = SYSCTL_TYPE(nnode.sysctl_flags);
824 	flags = SYSCTL_FLAGS(nnode.sysctl_flags);
825 	sz = nnode.sysctl_size;
826 
827 	/*
828 	 * find out if there's a collision, and if so, let the caller
829 	 * know what they collided with
830 	 */
831 	node = pnode->sysctl_child;
832 	at = 0;
833 	if (node) {
834 		if ((flags | node->sysctl_flags) & CTLFLAG_ANYNUMBER)
835 			/* No siblings for a CTLFLAG_ANYNUMBER node */
836 			return EINVAL;
837 		for (ni = 0; ni < pnode->sysctl_clen; ni++) {
838 			if (nm == node[ni].sysctl_num ||
839 			    strcmp(nnode.sysctl_name, node[ni].sysctl_name) == 0) {
840 				/*
841 				 * ignore error here, since we
842 				 * are already fixed on EEXIST
843 				 */
844 				(void)sysctl_cvt_out(l, v, &node[ni], oldp,
845 						     *oldlenp, oldlenp);
846 				return (EEXIST);
847 			}
848 			if (nm > node[ni].sysctl_num)
849 				at++;
850 		}
851 	}
852 
853 	/*
854 	 * use sysctl_ver to add to the tree iff it hasn't changed
855 	 */
856 	if (nnode.sysctl_ver != 0) {
857 		/*
858 		 * a specified value must match either the parent
859 		 * node's version or the root node's version
860 		 */
861 		if (nnode.sysctl_ver != sysctl_rootof(rnode)->sysctl_ver &&
862 		    nnode.sysctl_ver != rnode->sysctl_ver) {
863 			return (EINVAL);
864 		}
865 	}
866 
867 	/*
868 	 * only the kernel can assign functions to entries
869 	 */
870 	if (l != NULL && nnode.sysctl_func != NULL)
871 		return (EPERM);
872 
873 	/*
874 	 * only the kernel can create permanent entries, and only then
875 	 * before the kernel is finished setting itself up
876 	 */
877 	if (l != NULL && (flags & ~SYSCTL_USERFLAGS))
878 		return (EPERM);
879 	if ((flags & CTLFLAG_PERMANENT) &
880 	    (sysctl_root.sysctl_flags & CTLFLAG_PERMANENT))
881 		return (EPERM);
882 	if ((flags & (CTLFLAG_OWNDATA | CTLFLAG_IMMEDIATE)) ==
883 	    (CTLFLAG_OWNDATA | CTLFLAG_IMMEDIATE))
884 		return (EINVAL);
885 	if ((flags & CTLFLAG_IMMEDIATE) &&
886 	    type != CTLTYPE_INT && type != CTLTYPE_QUAD && type != CTLTYPE_BOOL)
887 		return (EINVAL);
888 
889 	/*
890 	 * check size, or set it if unset and we can figure it out.
891 	 * kernel created nodes are allowed to have a function instead
892 	 * of a size (or a data pointer).
893 	 */
894 	switch (type) {
895 	case CTLTYPE_NODE:
896 		/*
897 		 * only *i* can assert the size of a node
898 		 */
899 		if (flags & CTLFLAG_ALIAS) {
900 			anum = nnode.sysctl_alias;
901 			if (anum < 0)
902 				return (EINVAL);
903 			nnode.sysctl_alias = 0;
904 		}
905 		if (sz != 0 || nnode.sysctl_data != NULL)
906 			return (EINVAL);
907 		if (nnode.sysctl_csize != 0 ||
908 		    nnode.sysctl_clen != 0 ||
909 		    nnode.sysctl_child != 0)
910 			return (EINVAL);
911 		if (flags & CTLFLAG_OWNDATA)
912 			return (EINVAL);
913 		sz = sizeof(struct sysctlnode);
914 		break;
915 	case CTLTYPE_INT:
916 		/*
917 		 * since an int is an int, if the size is not given or
918 		 * is wrong, we can "int-uit" it.
919 		 */
920 		if (sz != 0 && sz != sizeof(int))
921 			return (EINVAL);
922 		sz = sizeof(int);
923 		break;
924 	case CTLTYPE_STRING:
925 		/*
926 		 * strings are a little more tricky
927 		 */
928 		if (sz == 0) {
929 			if (l == NULL) {
930 				if (nnode.sysctl_func == NULL) {
931 					if (nnode.sysctl_data == NULL)
932 						return (EINVAL);
933 					else
934 						sz = strlen(nnode.sysctl_data) +
935 						    1;
936 				}
937 			} else if (nnode.sysctl_data == NULL &&
938 				 flags & CTLFLAG_OWNDATA) {
939 				return (EINVAL);
940 			} else {
941 				char *vp, *e;
942 				size_t s;
943 
944 				/*
945 				 * we want a rough idea of what the
946 				 * size is now
947 				 */
948 				vp = malloc(PAGE_SIZE, M_SYSCTLDATA, M_WAITOK);
949 				if (vp == NULL)
950 					return (ENOMEM);
951 				e = nnode.sysctl_data;
952 				do {
953 					error = copyinstr(e, vp, PAGE_SIZE, &s);
954 					if (error) {
955 						if (error != ENAMETOOLONG) {
956 							free(vp, M_SYSCTLDATA);
957 							return (error);
958 						}
959 						e += PAGE_SIZE;
960 						if ((e - 32 * PAGE_SIZE) >
961 						    (char*)nnode.sysctl_data) {
962 							free(vp, M_SYSCTLDATA);
963 							return (ERANGE);
964 						}
965 					}
966 				} while (error != 0);
967 				sz = s + (e - (char*)nnode.sysctl_data);
968 				free(vp, M_SYSCTLDATA);
969 			}
970 		}
971 		break;
972 	case CTLTYPE_QUAD:
973 		if (sz != 0 && sz != sizeof(u_quad_t))
974 			return (EINVAL);
975 		sz = sizeof(u_quad_t);
976 		break;
977 	case CTLTYPE_BOOL:
978 		/*
979 		 * since an bool is an bool, if the size is not given or
980 		 * is wrong, we can "intuit" it.
981 		 */
982 		if (sz != 0 && sz != sizeof(bool))
983 			return (EINVAL);
984 		sz = sizeof(bool);
985 		break;
986 	case CTLTYPE_STRUCT:
987 		if (sz == 0) {
988 			if (l != NULL || nnode.sysctl_func == NULL)
989 				return (EINVAL);
990 			if (flags & CTLFLAG_OWNDATA)
991 				return (EINVAL);
992 		}
993 		break;
994 	default:
995 		return (EINVAL);
996 	}
997 
998 	/*
999 	 * at this point, if sz is zero, we *must* have a
1000 	 * function to go with it and we can't own it.
1001 	 */
1002 
1003 	/*
1004 	 *  l  ptr own
1005 	 *  0   0   0  -> EINVAL (if no func)
1006 	 *  0   0   1  -> own
1007 	 *  0   1   0  -> kptr
1008 	 *  0   1   1  -> kptr
1009 	 *  1   0   0  -> EINVAL
1010 	 *  1   0   1  -> own
1011 	 *  1   1   0  -> kptr, no own (fault on lookup)
1012 	 *  1   1   1  -> uptr, own
1013 	 */
1014 	if (type != CTLTYPE_NODE) {
1015 		if (sz != 0) {
1016 			if (flags & CTLFLAG_OWNDATA) {
1017 				own = malloc(sz, M_SYSCTLDATA, M_WAITOK);
1018 				if (own == NULL)
1019 					return ENOMEM;
1020 				if (nnode.sysctl_data == NULL)
1021 					memset(own, 0, sz);
1022 				else {
1023 					error = sysctl_copyin(l,
1024 					    nnode.sysctl_data, own, sz);
1025 					if (error != 0) {
1026 						free(own, M_SYSCTLDATA);
1027 						return (error);
1028 					}
1029 				}
1030 			} else if ((nnode.sysctl_data != NULL) &&
1031 				 !(flags & CTLFLAG_IMMEDIATE)) {
1032 #if NKSYMS > 0
1033 				if (name[namelen - 1] == CTL_CREATESYM) {
1034 					char symname[128]; /* XXX enough? */
1035 					u_long symaddr;
1036 					size_t symlen;
1037 
1038 					error = sysctl_copyinstr(l,
1039 					    nnode.sysctl_data, symname,
1040 					    sizeof(symname), &symlen);
1041 					if (error)
1042 						return (error);
1043 					error = ksyms_getval(NULL, symname,
1044 					    &symaddr, KSYMS_EXTERN);
1045 					if (error)
1046 						return (error); /* EINVAL? */
1047 					nnode.sysctl_data = (void*)symaddr;
1048 				}
1049 #endif /* NKSYMS > 0 */
1050 				/*
1051 				 * Ideally, we'd like to verify here
1052 				 * that this address is acceptable,
1053 				 * but...
1054 				 *
1055 				 * - it might be valid now, only to
1056 				 *   become invalid later
1057 				 *
1058 				 * - it might be invalid only for the
1059 				 *   moment and valid later
1060 				 *
1061 				 * - or something else.
1062 				 *
1063 				 * Since we can't get a good answer,
1064 				 * we'll just accept the address as
1065 				 * given, and fault on individual
1066 				 * lookups.
1067 				 */
1068 			}
1069 		} else if (nnode.sysctl_func == NULL)
1070 			return (EINVAL);
1071 	}
1072 
1073 	/*
1074 	 * a process can't assign a function to a node, and the kernel
1075 	 * can't create a node that has no function or data.
1076 	 * (XXX somewhat redundant check)
1077 	 */
1078 	if (l != NULL || nnode.sysctl_func == NULL) {
1079 		if (type != CTLTYPE_NODE &&
1080 		    !(flags & CTLFLAG_IMMEDIATE) &&
1081 		    nnode.sysctl_data == NULL &&
1082 		    own == NULL)
1083 			return (EINVAL);
1084 	}
1085 
1086 #ifdef SYSCTL_DISALLOW_KWRITE
1087 	/*
1088 	 * a process can't create a writable node unless it refers to
1089 	 * new data.
1090 	 */
1091 	if (l != NULL && own == NULL && type != CTLTYPE_NODE &&
1092 	    (flags & CTLFLAG_READWRITE) != CTLFLAG_READONLY &&
1093 	    !(flags & CTLFLAG_IMMEDIATE))
1094 		return (EPERM);
1095 #endif /* SYSCTL_DISALLOW_KWRITE */
1096 
1097 	/*
1098 	 * make sure there's somewhere to put the new stuff.
1099 	 */
1100 	if (pnode->sysctl_child == NULL) {
1101 		if (flags & CTLFLAG_ANYNUMBER)
1102 			error = sysctl_alloc(pnode, 1);
1103 		else
1104 			error = sysctl_alloc(pnode, 0);
1105 		if (error) {
1106 			if (own != NULL)
1107 				free(own, M_SYSCTLDATA);
1108 			return (error);
1109 		}
1110 	}
1111 	node = pnode->sysctl_child;
1112 
1113 	/*
1114 	 * no collisions, so pick a good dynamic number if we need to.
1115 	 */
1116 	if (nm == CTL_CREATE) {
1117 		nm = ++sysctl_root.sysctl_num;
1118 		for (ni = 0; ni < pnode->sysctl_clen; ni++) {
1119 			if (nm == node[ni].sysctl_num) {
1120 				nm++;
1121 				ni = -1;
1122 			} else if (nm > node[ni].sysctl_num)
1123 				at = ni + 1;
1124 		}
1125 	}
1126 
1127 	/*
1128 	 * oops...ran out of space
1129 	 */
1130 	if (pnode->sysctl_clen == pnode->sysctl_csize) {
1131 		error = sysctl_realloc(pnode);
1132 		if (error) {
1133 			if (own != NULL)
1134 				free(own, M_SYSCTLDATA);
1135 			return (error);
1136 		}
1137 		node = pnode->sysctl_child;
1138 	}
1139 
1140 	/*
1141 	 * insert new node data
1142 	 */
1143 	if (at < pnode->sysctl_clen) {
1144 		int t;
1145 
1146 		/*
1147 		 * move the nodes that should come after the new one
1148 		 */
1149 		memmove(&node[at + 1], &node[at],
1150 			(pnode->sysctl_clen - at) * sizeof(struct sysctlnode));
1151 		memset(&node[at], 0, sizeof(struct sysctlnode));
1152 		node[at].sysctl_parent = pnode;
1153 		/*
1154 		 * and...reparent any children of any moved nodes
1155 		 */
1156 		for (ni = at; ni <= pnode->sysctl_clen; ni++)
1157 			if (node[ni].sysctl_child != NULL)
1158 				for (t = 0; t < node[ni].sysctl_csize; t++)
1159 					node[ni].sysctl_child[t].sysctl_parent =
1160 						&node[ni];
1161 	}
1162 	node = &node[at];
1163 	pnode->sysctl_clen++;
1164 
1165 	strlcpy(node->sysctl_name, nnode.sysctl_name,
1166 		sizeof(node->sysctl_name));
1167 	node->sysctl_num = nm;
1168 	node->sysctl_size = sz;
1169 	node->sysctl_flags = SYSCTL_VERSION|type|flags; /* XXX other trees */
1170 	node->sysctl_csize = 0;
1171 	node->sysctl_clen = 0;
1172 	if (own) {
1173 		node->sysctl_data = own;
1174 		node->sysctl_flags |= CTLFLAG_OWNDATA;
1175 	} else if (flags & CTLFLAG_ALIAS) {
1176 		node->sysctl_alias = anum;
1177 	} else if (flags & CTLFLAG_IMMEDIATE) {
1178 		switch (type) {
1179 		case CTLTYPE_BOOL:
1180 			node->sysctl_bdata = nnode.sysctl_bdata;
1181 			break;
1182 		case CTLTYPE_INT:
1183 			node->sysctl_idata = nnode.sysctl_idata;
1184 			break;
1185 		case CTLTYPE_QUAD:
1186 			node->sysctl_qdata = nnode.sysctl_qdata;
1187 			break;
1188 		}
1189 	} else {
1190 		node->sysctl_data = nnode.sysctl_data;
1191 		node->sysctl_flags &= ~CTLFLAG_OWNDATA;
1192 	}
1193         node->sysctl_func = nnode.sysctl_func;
1194         node->sysctl_child = NULL;
1195 	/* node->sysctl_parent should already be done */
1196 
1197 	/*
1198 	 * update "version" on path to "root"
1199 	 */
1200 	for (; rnode->sysctl_parent != NULL; rnode = rnode->sysctl_parent)
1201 		;
1202 	pnode = node;
1203 	for (nm = rnode->sysctl_ver + 1; pnode != NULL;
1204 	     pnode = pnode->sysctl_parent)
1205 		pnode->sysctl_ver = nm;
1206 
1207 	/* If this fails, the node is already added - the user won't know! */
1208 	error = sysctl_cvt_out(l, v, node, oldp, *oldlenp, oldlenp);
1209 
1210 	return (error);
1211 }
1212 
1213 /*
1214  * ********************************************************************
1215  * A wrapper around sysctl_create() that prints the thing we're trying
1216  * to add.
1217  * ********************************************************************
1218  */
1219 #ifdef SYSCTL_DEBUG_CREATE
1220 int
1221 sysctl_create(SYSCTLFN_ARGS)
1222 {
1223 	const struct sysctlnode *node;
1224 	int k, rc, ni, nl = namelen + (name - oname);
1225 
1226 	node = newp;
1227 
1228 	printf("namelen %d (", nl);
1229 	for (ni = 0; ni < nl - 1; ni++)
1230 		printf(" %d", oname[ni]);
1231 	printf(" %d )\t[%s]\tflags %08x (%08x %d %zu)\n",
1232 	       k = node->sysctl_num,
1233 	       node->sysctl_name,
1234 	       node->sysctl_flags,
1235 	       SYSCTL_FLAGS(node->sysctl_flags),
1236 	       SYSCTL_TYPE(node->sysctl_flags),
1237 	       node->sysctl_size);
1238 
1239 	node = rnode;
1240 	rc = _sysctl_create(SYSCTLFN_CALL(rnode));
1241 
1242 	printf("sysctl_create(");
1243 	for (ni = 0; ni < nl - 1; ni++)
1244 		printf(" %d", oname[ni]);
1245 	printf(" %d ) returned %d\n", k, rc);
1246 
1247 	return (rc);
1248 }
1249 #endif /* SYSCTL_DEBUG_CREATE */
1250 
1251 /*
1252  * sysctl_destroy -- Removes a node (as described by newp) from the
1253  * given tree, returning (if successful) a copy of the dead node in
1254  * oldp.  Since we're removing stuff, there's not much to check.
1255  */
1256 int
1257 sysctl_destroy(SYSCTLFN_ARGS)
1258 {
1259 	struct sysctlnode *node, *pnode, onode, nnode;
1260 	int ni, error, v;
1261 
1262 	KASSERT(rw_write_held(&sysctl_treelock));
1263 
1264 	if (SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
1265 		printf("sysctl_destroy: rnode %p wrong version\n", rnode);
1266 		return (EINVAL);
1267 	}
1268 
1269 	error = 0;
1270 
1271 	if (namelen != 1 || name[namelen - 1] != CTL_DESTROY)
1272 		return (EINVAL);
1273 
1274 	/*
1275 	 * processes can only destroy nodes at securelevel 0, must be
1276 	 * root, and can't remove nodes from a parent that's not
1277 	 * writeable
1278 	 */
1279 	if (l != NULL) {
1280 #ifndef SYSCTL_DISALLOW_CREATE
1281 		error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SYSCTL,
1282 		    KAUTH_REQ_SYSTEM_SYSCTL_DELETE, NULL, NULL, NULL);
1283 		if (error)
1284 			return (error);
1285 		if (!(rnode->sysctl_flags & CTLFLAG_READWRITE))
1286 #endif /* SYSCTL_DISALLOW_CREATE */
1287 			return (EPERM);
1288 	}
1289 
1290 	/*
1291 	 * nothing can remove a node if:
1292 	 * the node is permanent (checked later) or
1293 	 * the tree itself is not writeable or
1294 	 * the entire sysctl system is not writeable
1295 	 *
1296 	 * note that we ignore whether setup is complete or not,
1297 	 * because these rules always apply.
1298 	 */
1299 	if (!(sysctl_rootof(rnode)->sysctl_flags & CTLFLAG_READWRITE) ||
1300 	    !(sysctl_root.sysctl_flags & CTLFLAG_READWRITE))
1301 		return (EPERM);
1302 
1303 	if (newp == NULL)
1304 		return (EINVAL);
1305 	error = sysctl_cvt_in(l, &v, newp, newlen, &nnode);
1306 	if (error)
1307 		return (error);
1308 	memset(&onode, 0, sizeof(struct sysctlnode));
1309 
1310 	node = rnode->sysctl_child;
1311 	for (ni = 0; ni < rnode->sysctl_clen; ni++) {
1312 		if (nnode.sysctl_num == node[ni].sysctl_num) {
1313 			/*
1314 			 * if name specified, must match
1315 			 */
1316 			if (nnode.sysctl_name[0] != '\0' &&
1317 			    strcmp(nnode.sysctl_name, node[ni].sysctl_name))
1318 				continue;
1319 			/*
1320 			 * if version specified, must match
1321 			 */
1322 			if (nnode.sysctl_ver != 0 &&
1323 			    nnode.sysctl_ver != node[ni].sysctl_ver)
1324 				continue;
1325 			/*
1326 			 * this must be the one
1327 			 */
1328 			break;
1329 		}
1330 	}
1331 	if (ni == rnode->sysctl_clen)
1332 		return (ENOENT);
1333 	node = &node[ni];
1334 	pnode = node->sysctl_parent;
1335 
1336 	/*
1337 	 * if the kernel says permanent, it is, so there.  nyah.
1338 	 */
1339 	if (SYSCTL_FLAGS(node->sysctl_flags) & CTLFLAG_PERMANENT)
1340 		return (EPERM);
1341 
1342 	/*
1343 	 * can't delete non-empty nodes
1344 	 */
1345 	if (SYSCTL_TYPE(node->sysctl_flags) == CTLTYPE_NODE &&
1346 	    node->sysctl_clen != 0)
1347 		return (ENOTEMPTY);
1348 
1349 	/*
1350 	 * if the node "owns" data, release it now
1351 	 */
1352 	if (node->sysctl_flags & CTLFLAG_OWNDATA) {
1353 		if (node->sysctl_data != NULL)
1354 			free(node->sysctl_data, M_SYSCTLDATA);
1355 		node->sysctl_data = NULL;
1356 	}
1357 	if (node->sysctl_flags & CTLFLAG_OWNDESC) {
1358 		if (node->sysctl_desc != NULL)
1359 			/*XXXUNCONST*/
1360 			free(__UNCONST(node->sysctl_desc), M_SYSCTLDATA);
1361 		node->sysctl_desc = NULL;
1362 	}
1363 
1364 	/*
1365 	 * if the node to be removed is not the last one on the list,
1366 	 * move the remaining nodes up, and reparent any grandchildren
1367 	 */
1368 	onode = *node;
1369 	if (ni < pnode->sysctl_clen - 1) {
1370 		int t;
1371 
1372 		memmove(&pnode->sysctl_child[ni], &pnode->sysctl_child[ni + 1],
1373 			(pnode->sysctl_clen - ni - 1) *
1374 			sizeof(struct sysctlnode));
1375 		for (; ni < pnode->sysctl_clen - 1; ni++)
1376 			if (SYSCTL_TYPE(pnode->sysctl_child[ni].sysctl_flags) ==
1377 			    CTLTYPE_NODE)
1378 				for (t = 0;
1379 				     t < pnode->sysctl_child[ni].sysctl_clen;
1380 				     t++)
1381 					pnode->sysctl_child[ni].sysctl_child[t].
1382 						sysctl_parent =
1383 						&pnode->sysctl_child[ni];
1384 		ni = pnode->sysctl_clen - 1;
1385 		node = &pnode->sysctl_child[ni];
1386 	}
1387 
1388 	/*
1389 	 * reset the space we just vacated
1390 	 */
1391 	memset(node, 0, sizeof(struct sysctlnode));
1392 	node->sysctl_parent = pnode;
1393 	pnode->sysctl_clen--;
1394 
1395 	/*
1396 	 * if this parent just lost its last child, nuke the creche
1397 	 */
1398 	if (pnode->sysctl_clen == 0) {
1399 		free(pnode->sysctl_child, M_SYSCTLNODE);
1400 		pnode->sysctl_csize = 0;
1401 		pnode->sysctl_child = NULL;
1402 	}
1403 
1404 	/*
1405 	 * update "version" on path to "root"
1406 	 */
1407         for (; rnode->sysctl_parent != NULL; rnode = rnode->sysctl_parent)
1408                 ;
1409 	for (ni = rnode->sysctl_ver + 1; pnode != NULL;
1410 	     pnode = pnode->sysctl_parent)
1411 		pnode->sysctl_ver = ni;
1412 
1413 	error = sysctl_cvt_out(l, v, &onode, oldp, *oldlenp, oldlenp);
1414 
1415 	return (error);
1416 }
1417 
1418 /*
1419  * sysctl_lookup -- Handles copyin/copyout of new and old values.
1420  * Partial reads are globally allowed.  Only root can write to things
1421  * unless the node says otherwise.
1422  */
1423 int
1424 sysctl_lookup(SYSCTLFN_ARGS)
1425 {
1426 	int error, rw;
1427 	size_t sz, len;
1428 	void *d;
1429 
1430 	KASSERT(rw_lock_held(&sysctl_treelock));
1431 
1432 	if (SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
1433 		printf("%s: rnode %p wrong version\n", __func__, rnode);
1434 		return EINVAL;
1435 	}
1436 
1437 	if (newlen == 0)
1438 		newp = NULL;
1439 
1440 	error = 0;
1441 
1442 	/*
1443 	 * you can't "look up" a node.  you can "query" it, but you
1444 	 * can't "look it up".
1445 	 */
1446 	if (SYSCTL_TYPE(rnode->sysctl_flags) == CTLTYPE_NODE || namelen != 0) {
1447 		DPRINTF(("%s: can't lookup a node\n", __func__));
1448 		return EINVAL;
1449 	}
1450 
1451 	/*
1452 	 * some nodes are private, so only root can look into them.
1453 	 */
1454 	if (l != NULL && (rnode->sysctl_flags & CTLFLAG_PRIVATE) &&
1455 	    (error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SYSCTL,
1456 	    KAUTH_REQ_SYSTEM_SYSCTL_PRVT, NULL, NULL, NULL)) != 0) {
1457 		DPRINTF(("%s: private node\n", __func__));
1458 		return error;
1459 	}
1460 
1461 	/*
1462 	 * if a node wants to be writable according to different rules
1463 	 * other than "only root can write to stuff unless a flag is
1464 	 * set", then it needs its own function which should have been
1465 	 * called and not us.
1466 	 */
1467 	if (l != NULL && newp != NULL &&
1468 	    !(rnode->sysctl_flags & CTLFLAG_ANYWRITE) &&
1469 	    (error = kauth_authorize_system(l->l_cred,
1470 	    KAUTH_SYSTEM_SYSCTL, KAUTH_REQ_SYSTEM_SYSCTL_MODIFY, NULL, NULL,
1471 	    NULL)) != 0) {
1472 		DPRINTF(("%s: can't modify\n", __func__));
1473 		return error;
1474 	}
1475 
1476 	/*
1477 	 * is this node supposedly writable?
1478 	 */
1479 	rw = (rnode->sysctl_flags & CTLFLAG_READWRITE) ? 1 : 0;
1480 
1481 	/*
1482 	 * it appears not to be writable at this time, so if someone
1483 	 * tried to write to it, we must tell them to go away
1484 	 */
1485 	if (!rw && newp != NULL) {
1486 		DPRINTF(("%s: not writable\n", __func__));
1487 		return EPERM;
1488 	}
1489 
1490 	/*
1491 	 * step one, copy out the stuff we have presently
1492 	 */
1493 	if (rnode->sysctl_flags & CTLFLAG_IMMEDIATE) {
1494 		/*
1495 		 * note that we discard const here because we are
1496 		 * modifying the contents of the node (which is okay
1497 		 * because it's ours)
1498 		 *
1499 		 * It also doesn't matter which field of the union we pick.
1500 		 */
1501 		d = __UNCONST(&rnode->sysctl_qdata);
1502 	} else
1503 		d = rnode->sysctl_data;
1504 
1505 	if (SYSCTL_TYPE(rnode->sysctl_flags) == CTLTYPE_STRING)
1506 		sz = strlen(d) + 1; /* XXX@@@ possible fault here */
1507 	else
1508 		sz = rnode->sysctl_size;
1509 	if (oldp != NULL) {
1510 		error = sysctl_copyout(l, d, oldp, MIN(sz, *oldlenp));
1511 		if (error) {
1512 			DPRINTF(("%s: bad copyout %d\n", __func__, error));
1513 			return error;
1514 		}
1515 	}
1516 	*oldlenp = sz;
1517 
1518 	/*
1519 	 * are we done?
1520 	 */
1521 	if (newp == NULL)
1522 		return 0;
1523 
1524 	/*
1525 	 * hmm...not done.  must now "copy in" new value.  re-adjust
1526 	 * sz to maximum value (strings are "weird").
1527 	 */
1528 	sz = rnode->sysctl_size;
1529 	switch (SYSCTL_TYPE(rnode->sysctl_flags)) {
1530 	case CTLTYPE_BOOL: {
1531 		bool tmp;
1532 		/*
1533 		 * these data must be *exactly* the same size coming
1534 		 * in.  bool may only be true or false.
1535 		 */
1536 		if (newlen != sz) {
1537 			DPRINTF(("%s: bad size %zu != %zu\n", __func__, newlen,
1538 			    sz));
1539 			return EINVAL;
1540 		}
1541 		error = sysctl_copyin(l, newp, &tmp, sz);
1542 		if (error)
1543 			break;
1544 		if (tmp != true && tmp != false) {
1545 			DPRINTF(("%s: tmp %d\n", __func__, tmp));
1546 			return EINVAL;
1547 		}
1548 		*(bool *)d = tmp;
1549 		break;
1550 	}
1551 	case CTLTYPE_INT:
1552 	case CTLTYPE_QUAD:
1553 	case CTLTYPE_STRUCT:
1554 		/*
1555 		 * these data must be *exactly* the same size coming
1556 		 * in.
1557 		 */
1558 		if (newlen != sz)
1559 			goto bad_size;
1560 		error = sysctl_copyin(l, newp, d, sz);
1561 		rnd_add_data(NULL, d, sz, 0);
1562 		break;
1563 	case CTLTYPE_STRING: {
1564 		/*
1565 		 * strings, on the other hand, can be shorter, and we
1566 		 * let userland be sloppy about the trailing nul.
1567 		 */
1568 		char *newbuf;
1569 
1570 		/*
1571 		 * too much new string?
1572 		 */
1573 		if (newlen > sz)
1574 			goto bad_size;
1575 
1576 		/*
1577 		 * temporary copy of new inbound string
1578 		 */
1579 		len = MIN(sz, newlen);
1580 		newbuf = malloc(len, M_SYSCTLDATA, M_WAITOK);
1581 		if (newbuf == NULL) {
1582 			DPRINTF(("%s: oomem %zu\n", __func__, len));
1583 			return ENOMEM;
1584 		}
1585 		error = sysctl_copyin(l, newp, newbuf, len);
1586 		if (error) {
1587 			free(newbuf, M_SYSCTLDATA);
1588 			DPRINTF(("%s: copyin %d\n", __func__, error));
1589 			return error;
1590 		}
1591 
1592 		/*
1593 		 * did they NUL terminate it, or do we have space
1594 		 * left to do it ourselves?
1595 		 */
1596 		if (newbuf[len - 1] != '\0' && len == sz) {
1597 			free(newbuf, M_SYSCTLDATA);
1598 			DPRINTF(("%s: string too long\n", __func__));
1599 			return EINVAL;
1600 		}
1601 
1602 		/*
1603 		 * looks good, so pop it into place and zero the rest.
1604 		 */
1605 		if (len > 0) {
1606 			memcpy(d, newbuf, len);
1607 			rnd_add_data(NULL, d, len, 0);
1608 		}
1609 		if (sz != len)
1610 			memset((char*)d + len, 0, sz - len);
1611 		free(newbuf, M_SYSCTLDATA);
1612 		break;
1613 	}
1614 	default:
1615 		DPRINTF(("%s: bad type\n", __func__));
1616 		return EINVAL;
1617 	}
1618 	if (error) {
1619 		DPRINTF(("%s: copyin %d\n", __func__, error));
1620 	}
1621 
1622 	return error;
1623 
1624     bad_size:
1625 	DPRINTF(("%s: bad size %zu > %zu\n", __func__, newlen, sz));
1626 	return EINVAL;
1627 }
1628 
1629 /*
1630  * sysctl_mmap -- Dispatches sysctl mmap requests to those nodes that
1631  * purport to handle it.  This interface isn't fully fleshed out yet,
1632  * unfortunately.
1633  */
1634 static int
1635 sysctl_mmap(SYSCTLFN_ARGS)
1636 {
1637 	const struct sysctlnode *node;
1638 	struct sysctlnode nnode;
1639 	int error;
1640 	int sysctl_num;
1641 
1642 	if (SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
1643 		printf("sysctl_mmap: rnode %p wrong version\n", rnode);
1644 		return (EINVAL);
1645 	}
1646 
1647 	/*
1648 	 * let's just pretend that didn't happen, m'kay?
1649 	 */
1650 	if (l == NULL)
1651 		return (EPERM);
1652 
1653 	/*
1654 	 * is this a sysctlnode description of an mmap request?
1655 	 */
1656 	if (newp == NULL || newlen != sizeof(struct sysctlnode))
1657 		return (EINVAL);
1658 	error = sysctl_copyin(l, newp, &nnode, sizeof(nnode));
1659 	if (error)
1660 		return (error);
1661 
1662 	/*
1663 	 * does the node they asked for exist?
1664 	 */
1665 	if (namelen != 1)
1666 		return (EOPNOTSUPP);
1667 	node = rnode;
1668 	sysctl_num = nnode.sysctl_num;
1669 	error = sysctl_locate(l, &sysctl_num, 1, &node, NULL);
1670 	if (error)
1671 		return (error);
1672 
1673 	/*
1674 	 * does this node that we have found purport to handle mmap?
1675 	 */
1676 	if (node->sysctl_func == NULL ||
1677 	    !(node->sysctl_flags & CTLFLAG_MMAP))
1678 		return (EOPNOTSUPP);
1679 
1680 	/*
1681 	 * well...okay, they asked for it.
1682 	 */
1683 	return ((*node->sysctl_func)(SYSCTLFN_CALL(node)));
1684 }
1685 
1686 int
1687 sysctl_describe(SYSCTLFN_ARGS)
1688 {
1689 	struct sysctldesc *d;
1690 	void *bf;
1691 	size_t sz, left, tot;
1692 	int i, error, v = -1;
1693 	struct sysctlnode *node;
1694 	struct sysctlnode dnode;
1695 
1696 	if (SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
1697 		printf("sysctl_query: rnode %p wrong version\n", rnode);
1698 		return (EINVAL);
1699 	}
1700 
1701 	if (SYSCTL_TYPE(rnode->sysctl_flags) != CTLTYPE_NODE)
1702 		return (ENOTDIR);
1703 	if (namelen != 1 || name[0] != CTL_DESCRIBE)
1704 		return (EINVAL);
1705 
1706 	/*
1707 	 * get ready...
1708 	 */
1709 	error = 0;
1710 	d = bf = malloc(MAXDESCLEN, M_TEMP, M_WAITOK);
1711 	if (bf == NULL)
1712 		return ENOMEM;
1713 	tot = 0;
1714 	node = rnode->sysctl_child;
1715 	left = *oldlenp;
1716 
1717 	/*
1718 	 * no request -> all descriptions at this level
1719 	 * request with desc unset -> just this node
1720 	 * request with desc set -> set descr for this node
1721 	 */
1722 	if (newp != NULL) {
1723 		error = sysctl_cvt_in(l, &v, newp, newlen, &dnode);
1724 		if (error)
1725 			goto out;
1726 		if (dnode.sysctl_desc != NULL) {
1727 			/*
1728 			 * processes cannot set descriptions above
1729 			 * securelevel 0.  and must be root.  blah
1730 			 * blah blah.  a couple more checks are made
1731 			 * once we find the node we want.
1732 			 */
1733 			if (l != NULL) {
1734 #ifndef SYSCTL_DISALLOW_CREATE
1735 				error = kauth_authorize_system(l->l_cred,
1736 				    KAUTH_SYSTEM_SYSCTL,
1737 				    KAUTH_REQ_SYSTEM_SYSCTL_DESC, NULL,
1738 				    NULL, NULL);
1739 				if (error)
1740 					goto out;
1741 #else /* SYSCTL_DISALLOW_CREATE */
1742 				error = EPERM;
1743 				goto out;
1744 #endif /* SYSCTL_DISALLOW_CREATE */
1745 			}
1746 
1747 			/*
1748 			 * find node and try to set the description on it
1749 			 */
1750 			for (i = 0; i < rnode->sysctl_clen; i++)
1751 				if (node[i].sysctl_num == dnode.sysctl_num)
1752 					break;
1753 			if (i == rnode->sysctl_clen) {
1754 				error = ENOENT;
1755 				goto out;
1756 			}
1757 			node = &node[i];
1758 
1759 			/*
1760 			 * did the caller specify a node version?
1761 			 */
1762 			if (dnode.sysctl_ver != 0 &&
1763 			    dnode.sysctl_ver != node->sysctl_ver) {
1764 				error = EINVAL;
1765 				goto out;
1766 			}
1767 
1768 			/*
1769 			 * okay...some rules:
1770 			 * (1) if setup is done and the tree is
1771 			 *     read-only or the whole system is
1772 			 *     read-only
1773 			 * (2) no one can set a description on a
1774 			 *     permanent node (it must be set when
1775 			 *     using createv)
1776 			 * (3) processes cannot *change* a description
1777 			 * (4) processes *can*, however, set a
1778 			 *     description on a read-only node so that
1779 			 *     one can be created and then described
1780 			 *     in two steps
1781 			 * anything else come to mind?
1782 			 */
1783 			if ((sysctl_root.sysctl_flags & CTLFLAG_PERMANENT) &&
1784 			    (!(sysctl_rootof(node)->sysctl_flags &
1785 			       CTLFLAG_READWRITE) ||
1786 			     !(sysctl_root.sysctl_flags & CTLFLAG_READWRITE))) {
1787 				error = EPERM;
1788 				goto out;
1789 			}
1790 			if (node->sysctl_flags & CTLFLAG_PERMANENT) {
1791 				error = EPERM;
1792 				goto out;
1793 			}
1794 			if (l != NULL && node->sysctl_desc != NULL) {
1795 				error = EPERM;
1796 				goto out;
1797 			}
1798 
1799 			/*
1800 			 * right, let's go ahead.  the first step is
1801 			 * making the description into something the
1802 			 * node can "own", if need be.
1803 			 */
1804 			if (l != NULL ||
1805 			    dnode.sysctl_flags & CTLFLAG_OWNDESC) {
1806 				char *nd, *k;
1807 
1808 				k = malloc(MAXDESCLEN, M_TEMP, M_WAITOK);
1809 				if (k == NULL) {
1810 					error = ENOMEM;
1811 					goto out;
1812 				}
1813 				error = sysctl_copyinstr(l, dnode.sysctl_desc,
1814 							 k, MAXDESCLEN, &sz);
1815 				if (error) {
1816 					free(k, M_TEMP);
1817 					goto out;
1818 				}
1819 				nd = malloc(sz, M_SYSCTLDATA, M_WAITOK);
1820 				if (nd == NULL) {
1821 					free(k, M_TEMP);
1822 					error = ENOMEM;
1823 					goto out;
1824 				}
1825 				memcpy(nd, k, sz);
1826 				dnode.sysctl_flags |= CTLFLAG_OWNDESC;
1827 				dnode.sysctl_desc = nd;
1828 				free(k, M_TEMP);
1829 			}
1830 
1831 			/*
1832 			 * now "release" the old description and
1833 			 * attach the new one.  ta-da.
1834 			 */
1835 			if ((node->sysctl_flags & CTLFLAG_OWNDESC) &&
1836 			    node->sysctl_desc != NULL)
1837 				/*XXXUNCONST*/
1838 				free(__UNCONST(node->sysctl_desc), M_SYSCTLDATA);
1839 			node->sysctl_desc = dnode.sysctl_desc;
1840 			node->sysctl_flags |=
1841 				(dnode.sysctl_flags & CTLFLAG_OWNDESC);
1842 
1843 			/*
1844 			 * now we "fall out" and into the loop which
1845 			 * will copy the new description back out for
1846 			 * those interested parties
1847 			 */
1848 		}
1849 	}
1850 
1851 	/*
1852 	 * scan for one description or just retrieve all descriptions
1853 	 */
1854 	for (i = 0; i < rnode->sysctl_clen; i++) {
1855 		/*
1856 		 * did they ask for the description of only one node?
1857 		 */
1858 		if (v != -1 && node[i].sysctl_num != dnode.sysctl_num)
1859 			continue;
1860 
1861 		/*
1862 		 * don't describe "private" nodes to non-suser users
1863 		 */
1864 		if ((node[i].sysctl_flags & CTLFLAG_PRIVATE) && (l != NULL) &&
1865 		    !(kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SYSCTL,
1866 		    KAUTH_REQ_SYSTEM_SYSCTL_PRVT, NULL, NULL, NULL)))
1867 			continue;
1868 
1869 		/*
1870 		 * is this description "valid"?
1871 		 */
1872 		memset(bf, 0, MAXDESCLEN);
1873 		if (node[i].sysctl_desc == NULL)
1874 			sz = 1;
1875 		else if (copystr(node[i].sysctl_desc, &d->descr_str[0],
1876 				 MAXDESCLEN - sizeof(*d), &sz) != 0) {
1877 			/*
1878 			 * erase possible partial description
1879 			 */
1880 			memset(bf, 0, MAXDESCLEN);
1881 			sz = 1;
1882 		}
1883 
1884 		/*
1885 		 * we've got it, stuff it into the caller's buffer
1886 		 */
1887 		d->descr_num = node[i].sysctl_num;
1888 		d->descr_ver = node[i].sysctl_ver;
1889 		d->descr_len = sz; /* includes trailing nul */
1890 		sz = (char *)NEXT_DESCR(d) - (char *)d;
1891 		if (oldp != NULL && left >= sz) {
1892 			error = sysctl_copyout(l, d, oldp, sz);
1893 			if (error)
1894 				goto out;
1895 			left -= sz;
1896 			oldp = (void *)__sysc_desc_adv(oldp, d->descr_len);
1897 		}
1898 		tot += sz;
1899 
1900 		/*
1901 		 * if we get this far with v not "unset", they asked
1902 		 * for a specific node and we found it
1903 		 */
1904 		if (v != -1)
1905 			break;
1906 	}
1907 
1908 	/*
1909 	 * did we find it after all?
1910 	 */
1911 	if (v != -1 && tot == 0)
1912 		error = ENOENT;
1913 	else
1914 		*oldlenp = tot;
1915 
1916 out:
1917 	free(bf, M_TEMP);
1918 	return (error);
1919 }
1920 
1921 /*
1922  * ********************************************************************
1923  * Section 3: Create and destroy from inside the kernel
1924  * ********************************************************************
1925  * sysctl_createv() and sysctl_destroyv() are simpler-to-use
1926  * interfaces for the kernel to fling new entries into the mib and rip
1927  * them out later.  In the case of sysctl_createv(), the returned copy
1928  * of the node (see sysctl_create()) will be translated back into a
1929  * pointer to the actual node.
1930  *
1931  * Note that sysctl_createv() will return 0 if the create request
1932  * matches an existing node (ala mkdir -p), and that sysctl_destroyv()
1933  * will return 0 if the node to be destroyed already does not exist
1934  * (aka rm -f) or if it is a parent of other nodes.
1935  *
1936  * This allows two (or more) different subsystems to assert sub-tree
1937  * existence before populating their own nodes, and to remove their
1938  * own nodes without orphaning the others when they are done.
1939  * ********************************************************************
1940  */
1941 #undef sysctl_createv
1942 int
1943 sysctl_createv(struct sysctllog **log, int cflags,
1944 	       const struct sysctlnode **rnode, const struct sysctlnode **cnode,
1945 	       int flags, int type, const char *namep, const char *descr,
1946 	       sysctlfn func, u_quad_t qv, void *newp, size_t newlen,
1947 	       ...)
1948 {
1949 	va_list ap;
1950 	int error, ni, namelen, name[CTL_MAXNAME];
1951 	const struct sysctlnode *root, *pnode;
1952 	struct sysctlnode nnode, onode, *dnode;
1953 	size_t sz;
1954 	const struct sysctlnode *snode __diagused;
1955 
1956 	/*
1957 	 * where are we putting this?
1958 	 */
1959 	if (rnode != NULL && *rnode == NULL) {
1960 		printf("sysctl_createv: rnode NULL\n");
1961 		return (EINVAL);
1962 	}
1963 	root = rnode ? *rnode : NULL;
1964 	if (cnode != NULL)
1965 		*cnode = NULL;
1966 	if (cflags != 0)
1967 		return (EINVAL);
1968 
1969 	/*
1970 	 * what is it?
1971 	 */
1972 	flags = SYSCTL_VERSION|SYSCTL_TYPE(type)|SYSCTL_FLAGS(flags);
1973 	if (log != NULL)
1974 		flags &= ~CTLFLAG_PERMANENT;
1975 
1976 	/*
1977 	 * where do we put it?
1978 	 */
1979 	va_start(ap, newlen);
1980 	namelen = 0;
1981 	error = 0;
1982 	ni = -1;
1983 	do {
1984 		if (++ni == CTL_MAXNAME) {
1985 			error = ENAMETOOLONG;
1986 			break;
1987 		}
1988 		name[ni] = va_arg(ap, int);
1989 		/*
1990 		 * sorry, this is not supported from here
1991 		 */
1992 		if (name[ni] == CTL_CREATESYM) {
1993 			error = EINVAL;
1994 			break;
1995 		}
1996 	} while (name[ni] != CTL_EOL && name[ni] != CTL_CREATE);
1997 	va_end(ap);
1998 	if (error)
1999 		return error;
2000 	namelen = ni + (name[ni] == CTL_CREATE ? 1 : 0);
2001 
2002 	/*
2003 	 * what's it called
2004 	 */
2005 	if (strlcpy(nnode.sysctl_name, namep, sizeof(nnode.sysctl_name)) >=
2006 	    sizeof(nnode.sysctl_name))
2007 		return (ENAMETOOLONG);
2008 
2009 	/*
2010 	 * cons up the description of the new node
2011 	 */
2012 	nnode.sysctl_num = name[namelen - 1];
2013 	name[namelen - 1] = CTL_CREATE;
2014 	nnode.sysctl_size = newlen;
2015 	nnode.sysctl_flags = flags;
2016 	if (type == CTLTYPE_NODE) {
2017 		nnode.sysctl_csize = 0;
2018 		nnode.sysctl_clen = 0;
2019 		nnode.sysctl_child = NULL;
2020 		if (flags & CTLFLAG_ALIAS)
2021 			nnode.sysctl_alias = qv;
2022 	} else if (flags & CTLFLAG_IMMEDIATE) {
2023 		switch (type) {
2024 		case CTLTYPE_BOOL:
2025 			nnode.sysctl_bdata = qv;
2026 			break;
2027 		case CTLTYPE_INT:
2028 			nnode.sysctl_idata = qv;
2029 			break;
2030 		case CTLTYPE_QUAD:
2031 			nnode.sysctl_qdata = qv;
2032 			break;
2033 		default:
2034 			return (EINVAL);
2035 		}
2036 	} else {
2037 		nnode.sysctl_data = newp;
2038 	}
2039 	nnode.sysctl_func = func;
2040 	nnode.sysctl_parent = NULL;
2041 	nnode.sysctl_ver = 0;
2042 
2043 	/*
2044 	 * initialize lock state -- we need locks if the main tree has
2045 	 * been marked as complete, but since we could be called from
2046 	 * either there, or from a device driver (say, at device
2047 	 * insertion), or from a module (at module load time, say), we
2048 	 * don't really want to "wait"...
2049 	 */
2050 	sysctl_lock(true);
2051 
2052 	/*
2053 	 * locate the prospective parent of the new node, and if we
2054 	 * find it, add the new node.
2055 	 */
2056 	sz = sizeof(onode);
2057 	pnode = root;
2058 	error = sysctl_locate(NULL, &name[0], namelen - 1, &pnode, &ni);
2059 	if (error) {
2060 		/*
2061 		 * XXX: If you are seeing this printf in early bringup
2062 		 * stages, perhaps your setfault is not functioning and
2063 		 * thus kcopy() is mis-behaving.
2064 		 */
2065 		printf("sysctl_createv: sysctl_locate(%s) returned %d\n",
2066 		       nnode.sysctl_name, error);
2067 		sysctl_unlock();
2068 		return (error);
2069 	}
2070 	error = sysctl_create(&name[ni], namelen - ni, &onode, &sz,
2071 			      &nnode, sizeof(nnode), &name[0], NULL,
2072 			      pnode);
2073 
2074 	/*
2075 	 * unfortunately the node we wanted to create is already
2076 	 * there.  if the node that's already there is a reasonable
2077 	 * facsimile of the node we wanted to create, just pretend
2078 	 * (for the caller's benefit) that we managed to create the
2079 	 * node they wanted.
2080 	 */
2081 	if (error == EEXIST) {
2082 		/* name is the same as requested... */
2083 		if (strcmp(nnode.sysctl_name, onode.sysctl_name) == 0 &&
2084 		    /* they want the same function... */
2085 		    nnode.sysctl_func == onode.sysctl_func &&
2086 		    /* number is the same as requested, or... */
2087 		    (nnode.sysctl_num == onode.sysctl_num ||
2088 		     /* they didn't pick a number... */
2089 		     nnode.sysctl_num == CTL_CREATE)) {
2090 			/*
2091 			 * collision here from trying to create
2092 			 * something that already existed; let's give
2093 			 * our customers a hand and tell them they got
2094 			 * what they wanted.
2095 			 */
2096 #ifdef SYSCTL_DEBUG_CREATE
2097 			printf("cleared\n");
2098 #endif /* SYSCTL_DEBUG_CREATE */
2099 			error = 0;
2100 		}
2101 	}
2102 
2103 	if (error == 0 &&
2104 	    (cnode != NULL || log != NULL || descr != NULL)) {
2105 		/*
2106 		 * sysctl_create() gave us back a copy of the node,
2107 		 * but we need to know where it actually is...
2108 		 */
2109 		pnode = root;
2110 		error = sysctl_locate(NULL, &name[0], namelen - 1, &pnode, &ni);
2111 		snode = pnode;
2112 
2113 		/*
2114 		 * manual scan of last layer so that aliased nodes
2115 		 * aren't followed.
2116 		 */
2117 		if (error == 0) {
2118 			for (ni = 0; ni < pnode->sysctl_clen; ni++)
2119 				if (pnode->sysctl_child[ni].sysctl_num ==
2120 				    onode.sysctl_num)
2121 					break;
2122 			if (ni < pnode->sysctl_clen)
2123 				pnode = &pnode->sysctl_child[ni];
2124 			else
2125 				error = ENOENT;
2126 		}
2127 
2128 		/*
2129 		 * not expecting an error here, but...
2130 		 */
2131 		if (error == 0) {
2132 			KASSERTMSG(pnode->sysctl_parent == snode,
2133 			    "sysctl parent mis-match pnode %s, snode %s",
2134 			    pnode->sysctl_name, snode->sysctl_name);
2135 			if (log != NULL)
2136 				sysctl_log_add(log, pnode);
2137 			if (cnode != NULL)
2138 				*cnode = pnode;
2139 			if (descr != NULL) {
2140 				/*
2141 				 * allow first caller to *set* a
2142 				 * description actually to set it
2143 				 *
2144 				 * discard const here so we can attach
2145 				 * the description
2146 				 */
2147 				dnode = __UNCONST(pnode);
2148 				if (pnode->sysctl_desc != NULL)
2149 					/* skip it...we've got one */;
2150 				else if (flags & CTLFLAG_OWNDESC) {
2151 					size_t l = strlen(descr) + 1;
2152 					char *d = malloc(l, M_SYSCTLDATA,
2153 							 M_WAITOK);
2154 					if (d != NULL) {
2155 						memcpy(d, descr, l);
2156 						dnode->sysctl_desc = d;
2157 						dnode->sysctl_flags |=
2158 						    CTLFLAG_OWNDESC;
2159 					}
2160 				} else
2161 					dnode->sysctl_desc = descr;
2162 			}
2163 		} else {
2164 			printf("sysctl_create succeeded but node not found?!\n");
2165 			/*
2166 			 *  confusing, but the create said it
2167 			 * succeeded, so...
2168 			 */
2169 			error = 0;
2170 		}
2171 	}
2172 
2173 	/*
2174 	 * now it should be safe to release the lock state.  note that
2175 	 * the pointer to the newly created node being passed back may
2176 	 * not be "good" for very long.
2177 	 */
2178 	sysctl_unlock();
2179 
2180 	if (error != 0) {
2181 		printf("sysctl_createv: sysctl_create(%s) returned %d\n",
2182 		       nnode.sysctl_name, error);
2183 #if 0
2184 		if (error != ENOENT)
2185 			sysctl_dump(&onode);
2186 #endif
2187 	}
2188 
2189 	return (error);
2190 }
2191 
2192 int
2193 sysctl_destroyv(struct sysctlnode *rnode, ...)
2194 {
2195 	va_list ap;
2196 	int error, name[CTL_MAXNAME], namelen, ni;
2197 	const struct sysctlnode *pnode, *node;
2198 	struct sysctlnode dnode, *onode;
2199 	size_t sz;
2200 
2201 	va_start(ap, rnode);
2202 	namelen = 0;
2203 	ni = 0;
2204 	do {
2205 		if (ni == CTL_MAXNAME) {
2206 			va_end(ap);
2207 			return (ENAMETOOLONG);
2208 		}
2209 		name[ni] = va_arg(ap, int);
2210 	} while (name[ni++] != CTL_EOL);
2211 	namelen = ni - 1;
2212 	va_end(ap);
2213 
2214 	/*
2215 	 * i can't imagine why we'd be destroying a node when the tree
2216 	 * wasn't complete, but who knows?
2217 	 */
2218 	sysctl_lock(true);
2219 
2220 	/*
2221 	 * where is it?
2222 	 */
2223 	node = rnode;
2224 	error = sysctl_locate(NULL, &name[0], namelen - 1, &node, &ni);
2225 	if (error) {
2226 		/* they want it gone and it's not there, so... */
2227 		sysctl_unlock();
2228 		return (error == ENOENT ? 0 : error);
2229 	}
2230 
2231 	/*
2232 	 * set up the deletion
2233 	 */
2234 	pnode = node;
2235 	node = &dnode;
2236 	memset(&dnode, 0, sizeof(dnode));
2237 	dnode.sysctl_flags = SYSCTL_VERSION;
2238 	dnode.sysctl_num = name[namelen - 1];
2239 
2240 	/*
2241 	 * we found it, now let's nuke it
2242 	 */
2243 	name[namelen - 1] = CTL_DESTROY;
2244 	sz = 0;
2245 	error = sysctl_destroy(&name[namelen - 1], 1, NULL, &sz,
2246 			       node, sizeof(*node), &name[0], NULL,
2247 			       pnode);
2248 	if (error == ENOTEMPTY) {
2249 		/*
2250 		 * think of trying to delete "foo" when "foo.bar"
2251 		 * (which someone else put there) is still in
2252 		 * existence
2253 		 */
2254 		error = 0;
2255 
2256 		/*
2257 		 * dunno who put the description there, but if this
2258 		 * node can ever be removed, we need to make sure the
2259 		 * string doesn't go out of context.  that means we
2260 		 * need to find the node that's still there (don't use
2261 		 * sysctl_locate() because that follows aliasing).
2262 		 */
2263 		node = pnode->sysctl_child;
2264 		for (ni = 0; ni < pnode->sysctl_clen; ni++)
2265 			if (node[ni].sysctl_num == dnode.sysctl_num)
2266 				break;
2267 		node = (ni < pnode->sysctl_clen) ? &node[ni] : NULL;
2268 
2269 		/*
2270 		 * if we found it, and this node has a description,
2271 		 * and this node can be released, and it doesn't
2272 		 * already own its own description...sigh.  :)
2273 		 */
2274 		if (node != NULL && node->sysctl_desc != NULL &&
2275 		    !(node->sysctl_flags & CTLFLAG_PERMANENT) &&
2276 		    !(node->sysctl_flags & CTLFLAG_OWNDESC)) {
2277 			char *d;
2278 
2279 			sz = strlen(node->sysctl_desc) + 1;
2280 			d = malloc(sz, M_SYSCTLDATA, M_WAITOK);
2281 			if (d != NULL) {
2282 				/*
2283 				 * discard const so that we can
2284 				 * re-attach the description
2285 				 */
2286 				memcpy(d, node->sysctl_desc, sz);
2287 				onode = __UNCONST(node);
2288 				onode->sysctl_desc = d;
2289 				onode->sysctl_flags |= CTLFLAG_OWNDESC;
2290 			} else {
2291 				/*
2292 				 * XXX drop the description?  be
2293 				 * afraid?  don't care?
2294 				 */
2295 			}
2296 		}
2297 	}
2298 
2299         sysctl_unlock();
2300 
2301 	return (error);
2302 }
2303 
2304 /*
2305  * ********************************************************************
2306  * Deletes an entire n-ary tree.  Not recommended unless you know why
2307  * you're doing it.  Personally, I don't know why you'd even think
2308  * about it.
2309  * ********************************************************************
2310  */
2311 void
2312 sysctl_free(struct sysctlnode *rnode)
2313 {
2314 	struct sysctlnode *node, *pnode;
2315 
2316 	rw_enter(&sysctl_treelock, RW_WRITER);
2317 
2318 	if (rnode == NULL)
2319 		rnode = &sysctl_root;
2320 
2321 	if (SYSCTL_VERS(rnode->sysctl_flags) != SYSCTL_VERSION) {
2322 		printf("sysctl_free: rnode %p wrong version\n", rnode);
2323 		rw_exit(&sysctl_treelock);
2324 		return;
2325 	}
2326 
2327 	pnode = rnode;
2328 
2329 	node = pnode->sysctl_child;
2330 	do {
2331 		while (node != NULL && pnode->sysctl_csize > 0) {
2332 			while (node <
2333 			       &pnode->sysctl_child[pnode->sysctl_clen] &&
2334 			       (SYSCTL_TYPE(node->sysctl_flags) !=
2335 				CTLTYPE_NODE ||
2336 				node->sysctl_csize == 0)) {
2337 				if (SYSCTL_FLAGS(node->sysctl_flags) &
2338 				    CTLFLAG_OWNDATA) {
2339 					if (node->sysctl_data != NULL) {
2340 						free(node->sysctl_data,
2341 						     M_SYSCTLDATA);
2342 						node->sysctl_data = NULL;
2343 					}
2344 				}
2345 				if (SYSCTL_FLAGS(node->sysctl_flags) &
2346 				    CTLFLAG_OWNDESC) {
2347 					if (node->sysctl_desc != NULL) {
2348 						/*XXXUNCONST*/
2349 						free(__UNCONST(node->sysctl_desc),
2350 						     M_SYSCTLDATA);
2351 						node->sysctl_desc = NULL;
2352 					}
2353 				}
2354 				node++;
2355 			}
2356 			if (node < &pnode->sysctl_child[pnode->sysctl_clen]) {
2357 				pnode = node;
2358 				node = node->sysctl_child;
2359 			} else
2360 				break;
2361 		}
2362 		if (pnode->sysctl_child != NULL)
2363 			free(pnode->sysctl_child, M_SYSCTLNODE);
2364 		pnode->sysctl_clen = 0;
2365 		pnode->sysctl_csize = 0;
2366 		pnode->sysctl_child = NULL;
2367 		node = pnode;
2368 		pnode = node->sysctl_parent;
2369 	} while (pnode != NULL && node != rnode);
2370 
2371 	rw_exit(&sysctl_treelock);
2372 }
2373 
2374 void
2375 sysctl_log_print(const struct sysctllog *slog)
2376 {
2377 	int i, len;
2378 
2379 	printf("root %p left %d size %d content", (const void *)slog->log_root,
2380 	    slog->log_left, slog->log_size);
2381 
2382 	for (len = 0, i = slog->log_left; i < slog->log_size; i++) {
2383 		switch (len) {
2384 		case 0:
2385 			len = -1;
2386 			printf(" version %d", slog->log_num[i]);
2387 			break;
2388 		case -1:
2389 			len = -2;
2390 			printf(" type %d", slog->log_num[i]);
2391 			break;
2392 		case -2:
2393 			len =  slog->log_num[i];
2394 			printf(" len %d:", slog->log_num[i]);
2395 			if (len <= 0)
2396 				len = -1;
2397 			break;
2398 		default:
2399 			len--;
2400 			printf(" %d", slog->log_num[i]);
2401 			break;
2402 		}
2403 	}
2404 	printf(" end\n");
2405 }
2406 
2407 int
2408 sysctl_log_add(struct sysctllog **logp, const struct sysctlnode *node)
2409 {
2410 	const int size0 = 16;
2411 	int name[CTL_MAXNAME], namelen, i;
2412 	const struct sysctlnode *pnode;
2413 	struct sysctllog *log;
2414 
2415 	if (node->sysctl_flags & CTLFLAG_PERMANENT)
2416 		return (0);
2417 
2418 	if (logp == NULL)
2419 		return (0);
2420 
2421 	if (*logp == NULL) {
2422 		log = malloc(sizeof(struct sysctllog),
2423 		       M_SYSCTLDATA, M_WAITOK);
2424 		if (log == NULL) {
2425 			/* XXX print error message? */
2426 			return (-1);
2427 		}
2428 		log->log_num = malloc(size0 * sizeof(int),
2429 		       M_SYSCTLDATA, M_WAITOK);
2430 		if (log->log_num == NULL) {
2431 			/* XXX print error message? */
2432 			free(log, M_SYSCTLDATA);
2433 			return (-1);
2434 		}
2435 		memset(log->log_num, 0, size0 * sizeof(int));
2436 		log->log_root = NULL;
2437 		log->log_size = size0;
2438 		log->log_left = size0;
2439 		*logp = log;
2440 	} else
2441 		log = *logp;
2442 
2443 	/*
2444 	 * check that the root is proper.  it's okay to record the
2445 	 * address of the root of a tree.  it's the only thing that's
2446 	 * guaranteed not to shift around as nodes come and go.
2447 	 */
2448 	if (log->log_root == NULL)
2449 		log->log_root = sysctl_rootof(node);
2450 	else if (log->log_root != sysctl_rootof(node)) {
2451 		printf("sysctl: log %p root mismatch (%p)\n",
2452 		       log->log_root, sysctl_rootof(node));
2453 		return (-1);
2454 	}
2455 
2456 	/*
2457 	 * we will copy out name in reverse order
2458 	 */
2459 	for (pnode = node, namelen = 0;
2460 	     pnode != NULL && !(pnode->sysctl_flags & CTLFLAG_ROOT);
2461 	     pnode = pnode->sysctl_parent)
2462 		name[namelen++] = pnode->sysctl_num;
2463 
2464 	/*
2465 	 * do we have space?
2466 	 */
2467 	if (log->log_left < (namelen + 3))
2468 		sysctl_log_realloc(log);
2469 	if (log->log_left < (namelen + 3))
2470 		return (-1);
2471 
2472 	/*
2473 	 * stuff name in, then namelen, then node type, and finally,
2474 	 * the version for non-node nodes.
2475 	 */
2476 	for (i = 0; i < namelen && i < CTL_MAXNAME; i++)
2477 		log->log_num[--log->log_left] = name[i];
2478 	log->log_num[--log->log_left] = namelen;
2479 	log->log_num[--log->log_left] = SYSCTL_TYPE(node->sysctl_flags);
2480 	if (log->log_num[log->log_left] != CTLTYPE_NODE)
2481 		log->log_num[--log->log_left] = node->sysctl_ver;
2482 	else
2483 		log->log_num[--log->log_left] = 0;
2484 
2485 	return (0);
2486 }
2487 
2488 void
2489 sysctl_teardown(struct sysctllog **logp)
2490 {
2491 	const struct sysctlnode *rnode;
2492 	struct sysctlnode node;
2493 	struct sysctllog *log;
2494 	uint namelen;
2495 	int *name, t, v, error, ni;
2496 	size_t sz;
2497 
2498 	if (logp == NULL || *logp == NULL)
2499 		return;
2500 	log = *logp;
2501 
2502 	rw_enter(&sysctl_treelock, RW_WRITER);
2503 	memset(&node, 0, sizeof(node));
2504 
2505 	while (log->log_left < log->log_size) {
2506 		KASSERT((log->log_left + 3 < log->log_size) &&
2507 			(log->log_left + log->log_num[log->log_left + 2] <=
2508 			 log->log_size));
2509 		v = log->log_num[log->log_left++];
2510 		t = log->log_num[log->log_left++];
2511 		namelen = log->log_num[log->log_left++];
2512 		name = &log->log_num[log->log_left];
2513 
2514 		node.sysctl_num = name[namelen - 1];
2515 		node.sysctl_flags = SYSCTL_VERSION|t;
2516 		node.sysctl_ver = v;
2517 
2518 		rnode = log->log_root;
2519 		error = sysctl_locate(NULL, &name[0], namelen, &rnode, &ni);
2520 		if (error == 0) {
2521 			name[namelen - 1] = CTL_DESTROY;
2522 			rnode = rnode->sysctl_parent;
2523 			sz = 0;
2524 			(void)sysctl_destroy(&name[namelen - 1], 1, NULL,
2525 					     &sz, &node, sizeof(node),
2526 					     &name[0], NULL, rnode);
2527 		}
2528 
2529 		log->log_left += namelen;
2530 	}
2531 
2532 	KASSERT(log->log_size == log->log_left);
2533 	free(log->log_num, M_SYSCTLDATA);
2534 	free(log, M_SYSCTLDATA);
2535 	*logp = NULL;
2536 
2537 	rw_exit(&sysctl_treelock);
2538 }
2539 
2540 /*
2541  * ********************************************************************
2542  * old_sysctl -- A routine to bridge old-style internal calls to the
2543  * new infrastructure.
2544  * ********************************************************************
2545  */
2546 int
2547 old_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
2548 	   void *newp, size_t newlen, struct lwp *l)
2549 {
2550 	int error;
2551 	size_t oldlen = 0;
2552 	size_t savelen;
2553 
2554 	if (oldlenp) {
2555 		oldlen = *oldlenp;
2556 	}
2557 	savelen = oldlen;
2558 
2559 	sysctl_lock(newp != NULL);
2560 	error = sysctl_dispatch(name, namelen, oldp, &oldlen,
2561 				newp, newlen, name, l, NULL);
2562 	sysctl_unlock();
2563 	if (error == 0 && oldp != NULL && savelen < oldlen)
2564 		error = ENOMEM;
2565 	if (oldlenp) {
2566 		*oldlenp = oldlen;
2567 	}
2568 
2569 	return (error);
2570 }
2571 
2572 /*
2573  * ********************************************************************
2574  * Section 4: Generic helper routines
2575  * ********************************************************************
2576  * "helper" routines that can do more finely grained access control,
2577  * construct structures from disparate information, create the
2578  * appearance of more nodes and sub-trees, etc.  for example, if
2579  * CTL_PROC wanted a helper function, it could respond to a CTL_QUERY
2580  * with a dynamically created list of nodes that represented the
2581  * currently running processes at that instant.
2582  * ********************************************************************
2583  */
2584 
2585 /*
2586  * first, a few generic helpers that provide:
2587  *
2588  * sysctl_needfunc()		a readonly interface that emits a warning
2589  * sysctl_notavail()		returns EOPNOTSUPP (generic error)
2590  * sysctl_null()		an empty return buffer with no error
2591  */
2592 int
2593 sysctl_needfunc(SYSCTLFN_ARGS)
2594 {
2595 	int error;
2596 
2597 	printf("!!SYSCTL_NEEDFUNC!!\n");
2598 
2599 	if (newp != NULL || namelen != 0)
2600 		return (EOPNOTSUPP);
2601 
2602 	error = 0;
2603 	if (oldp != NULL)
2604 		error = sysctl_copyout(l, rnode->sysctl_data, oldp,
2605 				       MIN(rnode->sysctl_size, *oldlenp));
2606 	*oldlenp = rnode->sysctl_size;
2607 
2608 	return (error);
2609 }
2610 
2611 int
2612 sysctl_notavail(SYSCTLFN_ARGS)
2613 {
2614 
2615 	if (namelen == 1 && name[0] == CTL_QUERY)
2616 		return (sysctl_query(SYSCTLFN_CALL(rnode)));
2617 
2618 	return (EOPNOTSUPP);
2619 }
2620 
2621 int
2622 sysctl_null(SYSCTLFN_ARGS)
2623 {
2624 
2625 	*oldlenp = 0;
2626 
2627 	return (0);
2628 }
2629 
2630 u_int
2631 sysctl_map_flags(const u_int *map, u_int word)
2632 {
2633 	u_int rv;
2634 
2635 	for (rv = 0; *map != 0; map += 2)
2636 		if ((word & map[0]) != 0)
2637 			rv |= map[1];
2638 
2639 	return rv;
2640 }
2641 
2642 /*
2643  * ********************************************************************
2644  * Section 5: The machinery that makes it all go
2645  * ********************************************************************
2646  * Memory "manglement" routines.  Not much to this, eh?
2647  * ********************************************************************
2648  */
2649 static int
2650 sysctl_alloc(struct sysctlnode *p, int x)
2651 {
2652 	int i;
2653 	struct sysctlnode *n;
2654 
2655 	assert(p->sysctl_child == NULL);
2656 
2657 	if (x == 1)
2658 		n = malloc(sizeof(struct sysctlnode),
2659 		       M_SYSCTLNODE, M_WAITOK);
2660 	else
2661 		n = malloc(SYSCTL_DEFSIZE * sizeof(struct sysctlnode),
2662 		       M_SYSCTLNODE, M_WAITOK);
2663 	if (n == NULL)
2664 		return (ENOMEM);
2665 
2666 	if (x == 1) {
2667 		memset(n, 0, sizeof(struct sysctlnode));
2668 		p->sysctl_csize = 1;
2669 	} else {
2670 		memset(n, 0, SYSCTL_DEFSIZE * sizeof(struct sysctlnode));
2671 		p->sysctl_csize = SYSCTL_DEFSIZE;
2672 	}
2673 	p->sysctl_clen = 0;
2674 
2675 	for (i = 0; i < p->sysctl_csize; i++)
2676 		n[i].sysctl_parent = p;
2677 
2678 	p->sysctl_child = n;
2679 	return (0);
2680 }
2681 
2682 static int
2683 sysctl_realloc(struct sysctlnode *p)
2684 {
2685 	int i, j, olen;
2686 	struct sysctlnode *n;
2687 
2688 	assert(p->sysctl_csize == p->sysctl_clen);
2689 
2690 	/*
2691 	 * how many do we have...how many should we make?
2692 	 */
2693 	olen = p->sysctl_clen;
2694 	n = malloc(2 * olen * sizeof(struct sysctlnode), M_SYSCTLNODE,
2695 		   M_WAITOK);
2696 	if (n == NULL)
2697 		return (ENOMEM);
2698 
2699 	/*
2700 	 * move old children over...initialize new children
2701 	 */
2702 	memcpy(n, p->sysctl_child, olen * sizeof(struct sysctlnode));
2703 	memset(&n[olen], 0, olen * sizeof(struct sysctlnode));
2704 	p->sysctl_csize = 2 * olen;
2705 
2706 	/*
2707 	 * reattach moved (and new) children to parent; if a moved
2708 	 * child node has children, reattach the parent pointers of
2709 	 * grandchildren
2710 	 */
2711         for (i = 0; i < p->sysctl_csize; i++) {
2712                 n[i].sysctl_parent = p;
2713 		if (n[i].sysctl_child != NULL) {
2714 			for (j = 0; j < n[i].sysctl_csize; j++)
2715 				n[i].sysctl_child[j].sysctl_parent = &n[i];
2716 		}
2717 	}
2718 
2719 	/*
2720 	 * get out with the old and in with the new
2721 	 */
2722 	free(p->sysctl_child, M_SYSCTLNODE);
2723 	p->sysctl_child = n;
2724 
2725 	return (0);
2726 }
2727 
2728 static int
2729 sysctl_log_realloc(struct sysctllog *log)
2730 {
2731 	int *n, s, d;
2732 
2733 	s = log->log_size * 2;
2734 	d = log->log_size;
2735 
2736 	n = malloc(s * sizeof(int), M_SYSCTLDATA, M_WAITOK);
2737 	if (n == NULL)
2738 		return (-1);
2739 
2740 	memset(n, 0, s * sizeof(int));
2741 	memcpy(&n[d], log->log_num, d * sizeof(int));
2742 	free(log->log_num, M_SYSCTLDATA);
2743 	log->log_num = n;
2744 	if (d)
2745 		log->log_left += d;
2746 	else
2747 		log->log_left = s;
2748 	log->log_size = s;
2749 
2750 	return (0);
2751 }
2752 
2753 /*
2754  * ********************************************************************
2755  * Section 6: Conversion between API versions wrt the sysctlnode
2756  * ********************************************************************
2757  */
2758 static int
2759 sysctl_cvt_in(struct lwp *l, int *vp, const void *i, size_t sz,
2760 	      struct sysctlnode *node)
2761 {
2762 	int error, flags;
2763 
2764 	if (i == NULL || sz < sizeof(flags))
2765 		return (EINVAL);
2766 
2767 	error = sysctl_copyin(l, i, &flags, sizeof(flags));
2768 	if (error)
2769 		return (error);
2770 
2771 #if (SYSCTL_VERSION != SYSCTL_VERS_1)
2772 #error sysctl_cvt_in: no support for SYSCTL_VERSION
2773 #endif /*  (SYSCTL_VERSION != SYSCTL_VERS_1) */
2774 
2775 	if (sz == sizeof(*node) &&
2776 	    SYSCTL_VERS(flags) == SYSCTL_VERSION) {
2777 		error = sysctl_copyin(l, i, node, sizeof(*node));
2778 		if (error)
2779 			return (error);
2780 		*vp = SYSCTL_VERSION;
2781 		return (0);
2782 	}
2783 
2784 	return (EINVAL);
2785 }
2786 
2787 static int
2788 sysctl_cvt_out(struct lwp *l, int v, const struct sysctlnode *i,
2789 	       void *ovp, size_t left, size_t *szp)
2790 {
2791 	size_t sz = sizeof(*i);
2792 	const void *src = i;
2793 	int error;
2794 
2795 	switch (v) {
2796 	case SYSCTL_VERS_0:
2797 		return (EINVAL);
2798 
2799 #if (SYSCTL_VERSION != SYSCTL_VERS_1)
2800 #error sysctl_cvt_out: no support for SYSCTL_VERSION
2801 #endif /*  (SYSCTL_VERSION != SYSCTL_VERS_1) */
2802 
2803 	case SYSCTL_VERSION:
2804 		/* nothing more to do here */
2805 		break;
2806 	}
2807 
2808 	if (ovp != NULL && left >= sz) {
2809 		error = sysctl_copyout(l, src, ovp, sz);
2810 		if (error)
2811 			return (error);
2812 	}
2813 
2814 	if (szp != NULL)
2815 		*szp = sz;
2816 
2817 	return (0);
2818 }
2819