xref: /freebsd/sys/kern/kern_sysctl.c (revision 84943d6f38e936ac3b7a3947ca26eeb27a39f938)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Mike Karels at Berkeley Software Design, Inc.
9  *
10  * Quite extensively rewritten by Poul-Henning Kamp of the FreeBSD
11  * project, to make these variables more userfriendly.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 #include <sys/cdefs.h>
39 #include "opt_capsicum.h"
40 #include "opt_ddb.h"
41 #include "opt_ktrace.h"
42 #include "opt_sysctl.h"
43 
44 #include <sys/param.h>
45 #include <sys/fail.h>
46 #include <sys/systm.h>
47 #include <sys/capsicum.h>
48 #include <sys/kernel.h>
49 #include <sys/limits.h>
50 #include <sys/sysctl.h>
51 #include <sys/malloc.h>
52 #include <sys/priv.h>
53 #include <sys/proc.h>
54 #include <sys/jail.h>
55 #include <sys/kdb.h>
56 #include <sys/lock.h>
57 #include <sys/mutex.h>
58 #include <sys/rmlock.h>
59 #include <sys/sbuf.h>
60 #include <sys/sx.h>
61 #include <sys/sysproto.h>
62 #include <sys/uio.h>
63 #ifdef KTRACE
64 #include <sys/ktrace.h>
65 #endif
66 
67 #ifdef DDB
68 #include <ddb/ddb.h>
69 #include <ddb/db_lex.h>
70 #endif
71 
72 #include <net/vnet.h>
73 
74 #include <security/mac/mac_framework.h>
75 
76 #include <vm/vm.h>
77 #include <vm/vm_extern.h>
78 
79 static MALLOC_DEFINE(M_SYSCTL, "sysctl", "sysctl internal magic");
80 static MALLOC_DEFINE(M_SYSCTLOID, "sysctloid", "sysctl dynamic oids");
81 static MALLOC_DEFINE(M_SYSCTLTMP, "sysctltmp", "sysctl temp output buffer");
82 
83 RB_GENERATE(sysctl_oid_list, sysctl_oid, oid_link, cmp_sysctl_oid);
84 
85 /*
86  * The sysctllock protects the MIB tree.  It also protects sysctl
87  * contexts used with dynamic sysctls.  The sysctl_register_oid() and
88  * sysctl_unregister_oid() routines require the sysctllock to already
89  * be held, so the sysctl_wlock() and sysctl_wunlock() routines are
90  * provided for the few places in the kernel which need to use that
91  * API rather than using the dynamic API.  Use of the dynamic API is
92  * strongly encouraged for most code.
93  *
94  * The sysctlmemlock is used to limit the amount of user memory wired for
95  * sysctl requests.  This is implemented by serializing any userland
96  * sysctl requests larger than a single page via an exclusive lock.
97  *
98  * The sysctlstringlock is used to protect concurrent access to writable
99  * string nodes in sysctl_handle_string().
100  */
101 static struct rmlock sysctllock;
102 static struct sx __exclusive_cache_line sysctlmemlock;
103 static struct sx sysctlstringlock;
104 
105 #define	SYSCTL_WLOCK()		rm_wlock(&sysctllock)
106 #define	SYSCTL_WUNLOCK()	rm_wunlock(&sysctllock)
107 #define	SYSCTL_RLOCK(tracker)	rm_rlock(&sysctllock, (tracker))
108 #define	SYSCTL_RUNLOCK(tracker)	rm_runlock(&sysctllock, (tracker))
109 #define	SYSCTL_WLOCKED()	rm_wowned(&sysctllock)
110 #define	SYSCTL_ASSERT_LOCKED()	rm_assert(&sysctllock, RA_LOCKED)
111 #define	SYSCTL_ASSERT_WLOCKED()	rm_assert(&sysctllock, RA_WLOCKED)
112 #define	SYSCTL_ASSERT_RLOCKED()	rm_assert(&sysctllock, RA_RLOCKED)
113 #define	SYSCTL_INIT()		rm_init_flags(&sysctllock, "sysctl lock", \
114 				    RM_SLEEPABLE)
115 #define	SYSCTL_SLEEP(ch, wmesg, timo)					\
116 				rm_sleep(ch, &sysctllock, 0, wmesg, timo)
117 
118 static int sysctl_root(SYSCTL_HANDLER_ARGS);
119 
120 /* Root list */
121 struct sysctl_oid_list sysctl__children = RB_INITIALIZER(&sysctl__children);
122 
123 static char*	sysctl_escape_name(const char*);
124 static int	sysctl_remove_oid_locked(struct sysctl_oid *oidp, int del,
125 		    int recurse);
126 static int	sysctl_old_kernel(struct sysctl_req *, const void *, size_t);
127 static int	sysctl_new_kernel(struct sysctl_req *, void *, size_t);
128 static int	name2oid(const char *, int *, int *, struct sysctl_oid **);
129 
130 static struct sysctl_oid *
131 sysctl_find_oidname(const char *name, struct sysctl_oid_list *list)
132 {
133 	struct sysctl_oid *oidp;
134 
135 	SYSCTL_ASSERT_LOCKED();
136 	SYSCTL_FOREACH(oidp, list) {
137 		if (strcmp(oidp->oid_name, name) == 0) {
138 			return (oidp);
139 		}
140 	}
141 	return (NULL);
142 }
143 
144 static struct sysctl_oid *
145 sysctl_find_oidnamelen(const char *name, size_t len,
146     struct sysctl_oid_list *list)
147 {
148 	struct sysctl_oid *oidp;
149 
150 	SYSCTL_ASSERT_LOCKED();
151 	SYSCTL_FOREACH(oidp, list) {
152 		if (strncmp(oidp->oid_name, name, len) == 0 &&
153 		    oidp->oid_name[len] == '\0')
154 			return (oidp);
155 	}
156 	return (NULL);
157 }
158 
159 /*
160  * Initialization of the MIB tree.
161  *
162  * Order by number in each list.
163  */
164 void
165 sysctl_wlock(void)
166 {
167 
168 	SYSCTL_WLOCK();
169 }
170 
171 void
172 sysctl_wunlock(void)
173 {
174 
175 	SYSCTL_WUNLOCK();
176 }
177 
178 static int
179 sysctl_root_handler_locked(struct sysctl_oid *oid, void *arg1, intmax_t arg2,
180     struct sysctl_req *req, struct rm_priotracker *tracker)
181 {
182 	int error;
183 
184 	if (oid->oid_kind & CTLFLAG_DYN)
185 		atomic_add_int(&oid->oid_running, 1);
186 
187 	if (tracker != NULL)
188 		SYSCTL_RUNLOCK(tracker);
189 	else
190 		SYSCTL_WUNLOCK();
191 
192 	/*
193 	 * Treat set CTLFLAG_NEEDGIANT and unset CTLFLAG_MPSAFE flags the same,
194 	 * untill we're ready to remove all traces of Giant from sysctl(9).
195 	 */
196 	if ((oid->oid_kind & CTLFLAG_NEEDGIANT) ||
197 	    (!(oid->oid_kind & CTLFLAG_MPSAFE)))
198 		mtx_lock(&Giant);
199 	error = oid->oid_handler(oid, arg1, arg2, req);
200 	if ((oid->oid_kind & CTLFLAG_NEEDGIANT) ||
201 	    (!(oid->oid_kind & CTLFLAG_MPSAFE)))
202 		mtx_unlock(&Giant);
203 
204 	KFAIL_POINT_ERROR(_debug_fail_point, sysctl_running, error);
205 
206 	if (tracker != NULL)
207 		SYSCTL_RLOCK(tracker);
208 	else
209 		SYSCTL_WLOCK();
210 
211 	if (oid->oid_kind & CTLFLAG_DYN) {
212 		if (atomic_fetchadd_int(&oid->oid_running, -1) == 1 &&
213 		    (oid->oid_kind & CTLFLAG_DYING) != 0)
214 			wakeup(&oid->oid_running);
215 	}
216 
217 	return (error);
218 }
219 
220 static void
221 sysctl_load_tunable_by_oid_locked(struct sysctl_oid *oidp)
222 {
223 	struct sysctl_req req;
224 	struct sysctl_oid *curr;
225 	char *penv = NULL;
226 	char path[96];
227 	ssize_t rem = sizeof(path);
228 	ssize_t len;
229 	uint8_t data[512] __aligned(sizeof(uint64_t));
230 	int size;
231 	int error;
232 
233 	path[--rem] = 0;
234 
235 	for (curr = oidp; curr != NULL; curr = SYSCTL_PARENT(curr)) {
236 		len = strlen(curr->oid_name);
237 		rem -= len;
238 		if (curr != oidp)
239 			rem -= 1;
240 		if (rem < 0) {
241 			printf("OID path exceeds %d bytes\n", (int)sizeof(path));
242 			return;
243 		}
244 		memcpy(path + rem, curr->oid_name, len);
245 		if (curr != oidp)
246 			path[rem + len] = '.';
247 	}
248 
249 	memset(&req, 0, sizeof(req));
250 
251 	req.td = curthread;
252 	req.oldfunc = sysctl_old_kernel;
253 	req.newfunc = sysctl_new_kernel;
254 	req.lock = REQ_UNWIRED;
255 
256 	switch (oidp->oid_kind & CTLTYPE) {
257 	case CTLTYPE_INT:
258 		if (getenv_array(path + rem, data, sizeof(data), &size,
259 		    sizeof(int), GETENV_SIGNED) == 0)
260 			return;
261 		req.newlen = size;
262 		req.newptr = data;
263 		break;
264 	case CTLTYPE_UINT:
265 		if (getenv_array(path + rem, data, sizeof(data), &size,
266 		    sizeof(int), GETENV_UNSIGNED) == 0)
267 			return;
268 		req.newlen = size;
269 		req.newptr = data;
270 		break;
271 	case CTLTYPE_LONG:
272 		if (getenv_array(path + rem, data, sizeof(data), &size,
273 		    sizeof(long), GETENV_SIGNED) == 0)
274 			return;
275 		req.newlen = size;
276 		req.newptr = data;
277 		break;
278 	case CTLTYPE_ULONG:
279 		if (getenv_array(path + rem, data, sizeof(data), &size,
280 		    sizeof(long), GETENV_UNSIGNED) == 0)
281 			return;
282 		req.newlen = size;
283 		req.newptr = data;
284 		break;
285 	case CTLTYPE_S8:
286 		if (getenv_array(path + rem, data, sizeof(data), &size,
287 		    sizeof(int8_t), GETENV_SIGNED) == 0)
288 			return;
289 		req.newlen = size;
290 		req.newptr = data;
291 		break;
292 	case CTLTYPE_S16:
293 		if (getenv_array(path + rem, data, sizeof(data), &size,
294 		    sizeof(int16_t), GETENV_SIGNED) == 0)
295 			return;
296 		req.newlen = size;
297 		req.newptr = data;
298 		break;
299 	case CTLTYPE_S32:
300 		if (getenv_array(path + rem, data, sizeof(data), &size,
301 		    sizeof(int32_t), GETENV_SIGNED) == 0)
302 			return;
303 		req.newlen = size;
304 		req.newptr = data;
305 		break;
306 	case CTLTYPE_S64:
307 		if (getenv_array(path + rem, data, sizeof(data), &size,
308 		    sizeof(int64_t), GETENV_SIGNED) == 0)
309 			return;
310 		req.newlen = size;
311 		req.newptr = data;
312 		break;
313 	case CTLTYPE_U8:
314 		if (getenv_array(path + rem, data, sizeof(data), &size,
315 		    sizeof(uint8_t), GETENV_UNSIGNED) == 0)
316 			return;
317 		req.newlen = size;
318 		req.newptr = data;
319 		break;
320 	case CTLTYPE_U16:
321 		if (getenv_array(path + rem, data, sizeof(data), &size,
322 		    sizeof(uint16_t), GETENV_UNSIGNED) == 0)
323 			return;
324 		req.newlen = size;
325 		req.newptr = data;
326 		break;
327 	case CTLTYPE_U32:
328 		if (getenv_array(path + rem, data, sizeof(data), &size,
329 		    sizeof(uint32_t), GETENV_UNSIGNED) == 0)
330 			return;
331 		req.newlen = size;
332 		req.newptr = data;
333 		break;
334 	case CTLTYPE_U64:
335 		if (getenv_array(path + rem, data, sizeof(data), &size,
336 		    sizeof(uint64_t), GETENV_UNSIGNED) == 0)
337 			return;
338 		req.newlen = size;
339 		req.newptr = data;
340 		break;
341 	case CTLTYPE_STRING:
342 		penv = kern_getenv(path + rem);
343 		if (penv == NULL)
344 			return;
345 		req.newlen = strlen(penv);
346 		req.newptr = penv;
347 		break;
348 	default:
349 		return;
350 	}
351 	error = sysctl_root_handler_locked(oidp, oidp->oid_arg1,
352 	    oidp->oid_arg2, &req, NULL);
353 	if (error != 0)
354 		printf("Setting sysctl %s failed: %d\n", path + rem, error);
355 	if (penv != NULL)
356 		freeenv(penv);
357 }
358 
359 /*
360  * Locate the path to a given oid.  Returns the length of the resulting path,
361  * or -1 if the oid was not found.  nodes must have room for CTL_MAXNAME
362  * elements.
363  */
364 static int
365 sysctl_search_oid(struct sysctl_oid **nodes, struct sysctl_oid *needle)
366 {
367 	int indx;
368 
369 	SYSCTL_ASSERT_LOCKED();
370 	indx = 0;
371 	/*
372 	 * Do a depth-first search of the oid tree, looking for 'needle'. Start
373 	 * with the first child of the root.
374 	 */
375 	nodes[indx] = RB_MIN(sysctl_oid_list, &sysctl__children);
376 	for (;;) {
377 		if (nodes[indx] == needle)
378 			return (indx + 1);
379 
380 		if (nodes[indx] == NULL) {
381 			/* Node has no more siblings, so back up to parent. */
382 			if (indx-- == 0) {
383 				/* Retreat to root, so give up. */
384 				break;
385 			}
386 		} else if ((nodes[indx]->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
387 			/* Node has children. */
388 			if (++indx == CTL_MAXNAME) {
389 				/* Max search depth reached, so give up. */
390 				break;
391 			}
392 			/* Start with the first child. */
393 			nodes[indx] = RB_MIN(sysctl_oid_list,
394 			    &nodes[indx - 1]->oid_children);
395 			continue;
396 		}
397 		/* Consider next sibling. */
398 		nodes[indx] = RB_NEXT(sysctl_oid_list, NULL, nodes[indx]);
399 	}
400 	return (-1);
401 }
402 
403 static void
404 sysctl_warn_reuse(const char *func, struct sysctl_oid *leaf)
405 {
406 	struct sysctl_oid *nodes[CTL_MAXNAME];
407 	char buf[128];
408 	struct sbuf sb;
409 	int rc, i;
410 
411 	(void)sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN | SBUF_INCLUDENUL);
412 	sbuf_set_drain(&sb, sbuf_printf_drain, NULL);
413 
414 	sbuf_printf(&sb, "%s: can't re-use a leaf (", __func__);
415 
416 	rc = sysctl_search_oid(nodes, leaf);
417 	if (rc > 0) {
418 		for (i = 0; i < rc; i++)
419 			sbuf_printf(&sb, "%s%.*s", nodes[i]->oid_name,
420 			    i != (rc - 1), ".");
421 	} else {
422 		sbuf_cat(&sb, leaf->oid_name);
423 	}
424 	sbuf_cat(&sb, ")!\n");
425 
426 	(void)sbuf_finish(&sb);
427 }
428 
429 #ifdef SYSCTL_DEBUG
430 static int
431 sysctl_reuse_test(SYSCTL_HANDLER_ARGS)
432 {
433 	struct rm_priotracker tracker;
434 
435 	SYSCTL_RLOCK(&tracker);
436 	sysctl_warn_reuse(__func__, oidp);
437 	SYSCTL_RUNLOCK(&tracker);
438 	return (0);
439 }
440 SYSCTL_PROC(_sysctl, OID_AUTO, reuse_test,
441     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0, sysctl_reuse_test, "-",
442     "");
443 #endif
444 
445 void
446 sysctl_register_oid(struct sysctl_oid *oidp)
447 {
448 	struct sysctl_oid_list *parent = oidp->oid_parent;
449 	struct sysctl_oid *p, key;
450 	int oid_number;
451 	int timeout = 2;
452 
453 	/*
454 	 * First check if another oid with the same name already
455 	 * exists in the parent's list.
456 	 */
457 	SYSCTL_ASSERT_WLOCKED();
458 	p = sysctl_find_oidname(oidp->oid_name, parent);
459 	if (p != NULL) {
460 		if ((p->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
461 			p->oid_refcnt++;
462 			return;
463 		} else {
464 			sysctl_warn_reuse(__func__, p);
465 			return;
466 		}
467 	}
468 	/* get current OID number */
469 	oid_number = oidp->oid_number;
470 
471 #if (OID_AUTO >= 0)
472 #error "OID_AUTO is expected to be a negative value"
473 #endif
474 	/*
475 	 * Any negative OID number qualifies as OID_AUTO. Valid OID
476 	 * numbers should always be positive.
477 	 *
478 	 * NOTE: DO NOT change the starting value here, change it in
479 	 * <sys/sysctl.h>, and make sure it is at least 256 to
480 	 * accommodate e.g. net.inet.raw as a static sysctl node.
481 	 */
482 	if (oid_number < 0) {
483 		static int newoid;
484 
485 		/*
486 		 * By decrementing the next OID number we spend less
487 		 * time inserting the OIDs into a sorted list.
488 		 */
489 		if (--newoid < CTL_AUTO_START)
490 			newoid = 0x7fffffff;
491 
492 		oid_number = newoid;
493 	}
494 
495 	/*
496 	 * Insert the OID into the parent's list sorted by OID number.
497 	 */
498 	key.oid_number = oid_number;
499 	p = RB_NFIND(sysctl_oid_list, parent, &key);
500 	while (p != NULL && oid_number == p->oid_number) {
501 		/* get the next valid OID number */
502 		if (oid_number < CTL_AUTO_START ||
503 		    oid_number == 0x7fffffff) {
504 			/* wraparound - restart */
505 			oid_number = CTL_AUTO_START;
506 			/* don't loop forever */
507 			if (!timeout--)
508 				panic("sysctl: Out of OID numbers\n");
509 			key.oid_number = oid_number;
510 			p = RB_NFIND(sysctl_oid_list, parent, &key);
511 			continue;
512 		}
513 		p = RB_NEXT(sysctl_oid_list, NULL, p);
514 		oid_number++;
515 	}
516 	/* check for non-auto OID number collision */
517 	if (oidp->oid_number >= 0 && oidp->oid_number < CTL_AUTO_START &&
518 	    oid_number >= CTL_AUTO_START) {
519 		printf("sysctl: OID number(%d) is already in use for '%s'\n",
520 		    oidp->oid_number, oidp->oid_name);
521 	}
522 	/* update the OID number, if any */
523 	oidp->oid_number = oid_number;
524 	RB_INSERT(sysctl_oid_list, parent, oidp);
525 
526 	if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE &&
527 	    (oidp->oid_kind & CTLFLAG_TUN) != 0 &&
528 	    (oidp->oid_kind & CTLFLAG_NOFETCH) == 0) {
529 #ifdef VIMAGE
530 		/*
531 		 * Can fetch value multiple times for VNET loader tunables.
532 		 * Only fetch once for non-VNET loader tunables.
533 		 */
534 		if ((oidp->oid_kind & CTLFLAG_VNET) == 0)
535 #endif
536 			oidp->oid_kind |= CTLFLAG_NOFETCH;
537 		/* try to fetch value from kernel environment */
538 		sysctl_load_tunable_by_oid_locked(oidp);
539 	}
540 }
541 
542 void
543 sysctl_register_disabled_oid(struct sysctl_oid *oidp)
544 {
545 
546 	/*
547 	 * Mark the leaf as dormant if it's not to be immediately enabled.
548 	 * We do not disable nodes as they can be shared between modules
549 	 * and it is always safe to access a node.
550 	 */
551 	KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0,
552 	    ("internal flag is set in oid_kind"));
553 	if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
554 		oidp->oid_kind |= CTLFLAG_DORMANT;
555 	sysctl_register_oid(oidp);
556 }
557 
558 void
559 sysctl_enable_oid(struct sysctl_oid *oidp)
560 {
561 
562 	SYSCTL_ASSERT_WLOCKED();
563 	if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
564 		KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0,
565 		    ("sysctl node is marked as dormant"));
566 		return;
567 	}
568 	KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) != 0,
569 	    ("enabling already enabled sysctl oid"));
570 	oidp->oid_kind &= ~CTLFLAG_DORMANT;
571 }
572 
573 void
574 sysctl_unregister_oid(struct sysctl_oid *oidp)
575 {
576 	int error;
577 
578 	SYSCTL_ASSERT_WLOCKED();
579 	if (oidp->oid_number == OID_AUTO) {
580 		error = EINVAL;
581 	} else {
582 		error = ENOENT;
583 		if (RB_REMOVE(sysctl_oid_list, oidp->oid_parent, oidp))
584 			error = 0;
585 	}
586 
587 	/*
588 	 * This can happen when a module fails to register and is
589 	 * being unloaded afterwards.  It should not be a panic()
590 	 * for normal use.
591 	 */
592 	if (error) {
593 		printf("%s: failed(%d) to unregister sysctl(%s)\n",
594 		    __func__, error, oidp->oid_name);
595 	}
596 }
597 
598 /* Initialize a new context to keep track of dynamically added sysctls. */
599 int
600 sysctl_ctx_init(struct sysctl_ctx_list *c)
601 {
602 
603 	if (c == NULL) {
604 		return (EINVAL);
605 	}
606 
607 	/*
608 	 * No locking here, the caller is responsible for not adding
609 	 * new nodes to a context until after this function has
610 	 * returned.
611 	 */
612 	TAILQ_INIT(c);
613 	return (0);
614 }
615 
616 /* Free the context, and destroy all dynamic oids registered in this context */
617 int
618 sysctl_ctx_free(struct sysctl_ctx_list *clist)
619 {
620 	struct sysctl_ctx_entry *e, *e1;
621 	int error;
622 
623 	error = 0;
624 	/*
625 	 * First perform a "dry run" to check if it's ok to remove oids.
626 	 * XXX FIXME
627 	 * XXX This algorithm is a hack. But I don't know any
628 	 * XXX better solution for now...
629 	 */
630 	SYSCTL_WLOCK();
631 	TAILQ_FOREACH(e, clist, link) {
632 		error = sysctl_remove_oid_locked(e->entry, 0, 0);
633 		if (error)
634 			break;
635 	}
636 	/*
637 	 * Restore deregistered entries, either from the end,
638 	 * or from the place where error occurred.
639 	 * e contains the entry that was not unregistered
640 	 */
641 	if (error)
642 		e1 = TAILQ_PREV(e, sysctl_ctx_list, link);
643 	else
644 		e1 = TAILQ_LAST(clist, sysctl_ctx_list);
645 	while (e1 != NULL) {
646 		sysctl_register_oid(e1->entry);
647 		e1 = TAILQ_PREV(e1, sysctl_ctx_list, link);
648 	}
649 	if (error) {
650 		SYSCTL_WUNLOCK();
651 		return(EBUSY);
652 	}
653 	/* Now really delete the entries */
654 	TAILQ_FOREACH_SAFE(e, clist, link, e1) {
655 		error = sysctl_remove_oid_locked(e->entry, 1, 0);
656 		if (error)
657 			panic("sysctl_remove_oid: corrupt tree, entry: %s",
658 			    e->entry->oid_name);
659 		free(e, M_SYSCTLOID);
660 	}
661 	SYSCTL_WUNLOCK();
662 	TAILQ_INIT(clist);
663 	return (error);
664 }
665 
666 /* Add an entry to the context */
667 struct sysctl_ctx_entry *
668 sysctl_ctx_entry_add(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
669 {
670 	struct sysctl_ctx_entry *e;
671 
672 	SYSCTL_ASSERT_WLOCKED();
673 	if (clist == NULL || oidp == NULL)
674 		return(NULL);
675 	e = malloc(sizeof(struct sysctl_ctx_entry), M_SYSCTLOID, M_WAITOK);
676 	e->entry = oidp;
677 	TAILQ_INSERT_HEAD(clist, e, link);
678 	return (e);
679 }
680 
681 /* Find an entry in the context */
682 struct sysctl_ctx_entry *
683 sysctl_ctx_entry_find(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
684 {
685 	struct sysctl_ctx_entry *e;
686 
687 	SYSCTL_ASSERT_WLOCKED();
688 	if (clist == NULL || oidp == NULL)
689 		return(NULL);
690 	TAILQ_FOREACH(e, clist, link) {
691 		if (e->entry == oidp)
692 			return(e);
693 	}
694 	return (e);
695 }
696 
697 /*
698  * Delete an entry from the context.
699  * NOTE: this function doesn't free oidp! You have to remove it
700  * with sysctl_remove_oid().
701  */
702 int
703 sysctl_ctx_entry_del(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
704 {
705 	struct sysctl_ctx_entry *e;
706 
707 	if (clist == NULL || oidp == NULL)
708 		return (EINVAL);
709 	SYSCTL_WLOCK();
710 	e = sysctl_ctx_entry_find(clist, oidp);
711 	if (e != NULL) {
712 		TAILQ_REMOVE(clist, e, link);
713 		SYSCTL_WUNLOCK();
714 		free(e, M_SYSCTLOID);
715 		return (0);
716 	} else {
717 		SYSCTL_WUNLOCK();
718 		return (ENOENT);
719 	}
720 }
721 
722 /*
723  * Remove dynamically created sysctl trees.
724  * oidp - top of the tree to be removed
725  * del - if 0 - just deregister, otherwise free up entries as well
726  * recurse - if != 0 traverse the subtree to be deleted
727  */
728 int
729 sysctl_remove_oid(struct sysctl_oid *oidp, int del, int recurse)
730 {
731 	int error;
732 
733 	SYSCTL_WLOCK();
734 	error = sysctl_remove_oid_locked(oidp, del, recurse);
735 	SYSCTL_WUNLOCK();
736 	return (error);
737 }
738 
739 int
740 sysctl_remove_name(struct sysctl_oid *parent, const char *name,
741     int del, int recurse)
742 {
743 	struct sysctl_oid *p;
744 	int error;
745 
746 	error = ENOENT;
747 	SYSCTL_WLOCK();
748 	p = sysctl_find_oidname(name, &parent->oid_children);
749 	if (p)
750 		error = sysctl_remove_oid_locked(p, del, recurse);
751 	SYSCTL_WUNLOCK();
752 
753 	return (error);
754 }
755 
756 /*
757  * Duplicate the provided string, escaping any illegal characters.  The result
758  * must be freed when no longer in use.
759  *
760  * The list of illegal characters is ".".
761  */
762 static char*
763 sysctl_escape_name(const char* orig)
764 {
765 	int i, s = 0, d = 0, nillegals = 0;
766 	char *new;
767 
768 	/* First count the number of illegal characters */
769 	for (i = 0; orig[i] != '\0'; i++) {
770 		if (orig[i] == '.')
771 			nillegals++;
772 	}
773 
774 	/* Allocate storage for new string */
775 	new = malloc(i + 2 * nillegals + 1, M_SYSCTLOID, M_WAITOK);
776 
777 	/* Copy the name, escaping characters as we go */
778 	while (orig[s] != '\0') {
779 		if (orig[s] == '.') {
780 			/* %25 is the hexadecimal representation of '.' */
781 			new[d++] = '%';
782 			new[d++] = '2';
783 			new[d++] = '5';
784 			s++;
785 		} else {
786 			new[d++] = orig[s++];
787 		}
788 	}
789 
790 	/* Finally, nul-terminate */
791 	new[d] = '\0';
792 
793 	return (new);
794 }
795 
796 static int
797 sysctl_remove_oid_locked(struct sysctl_oid *oidp, int del, int recurse)
798 {
799 	struct sysctl_oid *p, *tmp;
800 	int error;
801 
802 	SYSCTL_ASSERT_WLOCKED();
803 	if (oidp == NULL)
804 		return(EINVAL);
805 	if ((oidp->oid_kind & CTLFLAG_DYN) == 0) {
806 		printf("Warning: can't remove non-dynamic nodes (%s)!\n",
807 		    oidp->oid_name);
808 		return (EINVAL);
809 	}
810 	/*
811 	 * WARNING: normal method to do this should be through
812 	 * sysctl_ctx_free(). Use recursing as the last resort
813 	 * method to purge your sysctl tree of leftovers...
814 	 * However, if some other code still references these nodes,
815 	 * it will panic.
816 	 */
817 	if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
818 		if (oidp->oid_refcnt == 1) {
819 			for(p = RB_MIN(sysctl_oid_list, &oidp->oid_children);
820 			    p != NULL; p = tmp) {
821 				if (!recurse) {
822 					printf("Warning: failed attempt to "
823 					    "remove oid %s with child %s\n",
824 					    oidp->oid_name, p->oid_name);
825 					return (ENOTEMPTY);
826 				}
827 				tmp = RB_NEXT(sysctl_oid_list,
828 				    &oidp->oid_children, p);
829 				error = sysctl_remove_oid_locked(p, del,
830 				    recurse);
831 				if (error)
832 					return (error);
833 			}
834 		}
835 	}
836 	if (oidp->oid_refcnt > 1 ) {
837 		oidp->oid_refcnt--;
838 	} else {
839 		if (oidp->oid_refcnt == 0) {
840 			printf("Warning: bad oid_refcnt=%u (%s)!\n",
841 				oidp->oid_refcnt, oidp->oid_name);
842 			return (EINVAL);
843 		}
844 		sysctl_unregister_oid(oidp);
845 		if (del) {
846 			/*
847 			 * Wait for all threads running the handler to drain.
848 			 * This preserves the previous behavior when the
849 			 * sysctl lock was held across a handler invocation,
850 			 * and is necessary for module unload correctness.
851 			 */
852 			while (oidp->oid_running > 0) {
853 				oidp->oid_kind |= CTLFLAG_DYING;
854 				SYSCTL_SLEEP(&oidp->oid_running, "oidrm", 0);
855 			}
856 			if (oidp->oid_descr)
857 				free(__DECONST(char *, oidp->oid_descr),
858 				    M_SYSCTLOID);
859 			if (oidp->oid_label)
860 				free(__DECONST(char *, oidp->oid_label),
861 				    M_SYSCTLOID);
862 			free(__DECONST(char *, oidp->oid_name), M_SYSCTLOID);
863 			free(oidp, M_SYSCTLOID);
864 		}
865 	}
866 	return (0);
867 }
868 /*
869  * Create new sysctls at run time.
870  * clist may point to a valid context initialized with sysctl_ctx_init().
871  */
872 struct sysctl_oid *
873 sysctl_add_oid(struct sysctl_ctx_list *clist, struct sysctl_oid_list *parent,
874 	int number, const char *name, int kind, void *arg1, intmax_t arg2,
875 	int (*handler)(SYSCTL_HANDLER_ARGS), const char *fmt, const char *descr,
876 	const char *label)
877 {
878 	struct sysctl_oid *oidp;
879 	char *escaped;
880 
881 	/* You have to hook up somewhere.. */
882 	if (parent == NULL)
883 		return(NULL);
884 	escaped = sysctl_escape_name(name);
885 	/* Check if the node already exists, otherwise create it */
886 	SYSCTL_WLOCK();
887 	oidp = sysctl_find_oidname(escaped, parent);
888 	if (oidp != NULL) {
889 		free(escaped, M_SYSCTLOID);
890 		if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
891 			oidp->oid_refcnt++;
892 			/* Update the context */
893 			if (clist != NULL)
894 				sysctl_ctx_entry_add(clist, oidp);
895 			SYSCTL_WUNLOCK();
896 			return (oidp);
897 		} else {
898 			sysctl_warn_reuse(__func__, oidp);
899 			SYSCTL_WUNLOCK();
900 			return (NULL);
901 		}
902 	}
903 	oidp = malloc(sizeof(struct sysctl_oid), M_SYSCTLOID, M_WAITOK|M_ZERO);
904 	oidp->oid_parent = parent;
905 	RB_INIT(&oidp->oid_children);
906 	oidp->oid_number = number;
907 	oidp->oid_refcnt = 1;
908 	oidp->oid_name = escaped;
909 	oidp->oid_handler = handler;
910 	oidp->oid_kind = CTLFLAG_DYN | kind;
911 	oidp->oid_arg1 = arg1;
912 	oidp->oid_arg2 = arg2;
913 	oidp->oid_fmt = fmt;
914 	if (descr != NULL)
915 		oidp->oid_descr = strdup(descr, M_SYSCTLOID);
916 	if (label != NULL)
917 		oidp->oid_label = strdup(label, M_SYSCTLOID);
918 	/* Update the context, if used */
919 	if (clist != NULL)
920 		sysctl_ctx_entry_add(clist, oidp);
921 	/* Register this oid */
922 	sysctl_register_oid(oidp);
923 	SYSCTL_WUNLOCK();
924 	return (oidp);
925 }
926 
927 /*
928  * Rename an existing oid.
929  */
930 void
931 sysctl_rename_oid(struct sysctl_oid *oidp, const char *name)
932 {
933 	char *newname;
934 	char *oldname;
935 
936 	newname = strdup(name, M_SYSCTLOID);
937 	SYSCTL_WLOCK();
938 	oldname = __DECONST(char *, oidp->oid_name);
939 	oidp->oid_name = newname;
940 	SYSCTL_WUNLOCK();
941 	free(oldname, M_SYSCTLOID);
942 }
943 
944 /*
945  * Reparent an existing oid.
946  */
947 int
948 sysctl_move_oid(struct sysctl_oid *oid, struct sysctl_oid_list *parent)
949 {
950 	struct sysctl_oid *oidp;
951 
952 	SYSCTL_WLOCK();
953 	if (oid->oid_parent == parent) {
954 		SYSCTL_WUNLOCK();
955 		return (0);
956 	}
957 	oidp = sysctl_find_oidname(oid->oid_name, parent);
958 	if (oidp != NULL) {
959 		SYSCTL_WUNLOCK();
960 		return (EEXIST);
961 	}
962 	sysctl_unregister_oid(oid);
963 	oid->oid_parent = parent;
964 	oid->oid_number = OID_AUTO;
965 	sysctl_register_oid(oid);
966 	SYSCTL_WUNLOCK();
967 	return (0);
968 }
969 
970 /*
971  * Register the kernel's oids on startup.
972  */
973 SET_DECLARE(sysctl_set, struct sysctl_oid);
974 
975 static void
976 sysctl_register_all(void *arg)
977 {
978 	struct sysctl_oid **oidp;
979 
980 	sx_init(&sysctlmemlock, "sysctl mem");
981 	sx_init(&sysctlstringlock, "sysctl string handler");
982 	SYSCTL_INIT();
983 	SYSCTL_WLOCK();
984 	SET_FOREACH(oidp, sysctl_set)
985 		sysctl_register_oid(*oidp);
986 	SYSCTL_WUNLOCK();
987 }
988 SYSINIT(sysctl, SI_SUB_KMEM, SI_ORDER_FIRST, sysctl_register_all, NULL);
989 
990 #ifdef VIMAGE
991 static void
992 sysctl_setenv_vnet(void *arg __unused, const char *name)
993 {
994 	struct sysctl_oid *oidp;
995 	int oid[CTL_MAXNAME];
996 	int error, nlen;
997 
998 	SYSCTL_WLOCK();
999 	error = name2oid(name, oid, &nlen, &oidp);
1000 	if (error)
1001 		goto out;
1002 
1003 	if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE &&
1004 	    (oidp->oid_kind & CTLFLAG_VNET) != 0 &&
1005 	    (oidp->oid_kind & CTLFLAG_TUN) != 0 &&
1006 	    (oidp->oid_kind & CTLFLAG_NOFETCH) == 0) {
1007 		/* Update value from kernel environment */
1008 		sysctl_load_tunable_by_oid_locked(oidp);
1009 	}
1010 out:
1011 	SYSCTL_WUNLOCK();
1012 }
1013 
1014 static void
1015 sysctl_unsetenv_vnet(void *arg __unused, const char *name)
1016 {
1017 	struct sysctl_oid *oidp;
1018 	int oid[CTL_MAXNAME];
1019 	int error, nlen;
1020 
1021 	SYSCTL_WLOCK();
1022 	/*
1023 	 * The setenv / unsetenv event handlers are invoked by kern_setenv() /
1024 	 * kern_unsetenv() without exclusive locks. It is rare but still possible
1025 	 * that the invoke order of event handlers is different from that of
1026 	 * kern_setenv() and kern_unsetenv().
1027 	 * Re-check environment variable string to make sure it is unset.
1028 	 */
1029 	if (testenv(name))
1030 		goto out;
1031 	error = name2oid(name, oid, &nlen, &oidp);
1032 	if (error)
1033 		goto out;
1034 
1035 	if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE &&
1036 	    (oidp->oid_kind & CTLFLAG_VNET) != 0 &&
1037 	    (oidp->oid_kind & CTLFLAG_TUN) != 0 &&
1038 	    (oidp->oid_kind & CTLFLAG_NOFETCH) == 0) {
1039 		size_t size;
1040 
1041 		switch (oidp->oid_kind & CTLTYPE) {
1042 		case CTLTYPE_INT:
1043 		case CTLTYPE_UINT:
1044 			size = sizeof(int);
1045 			break;
1046 		case CTLTYPE_LONG:
1047 		case CTLTYPE_ULONG:
1048 			size = sizeof(long);
1049 			break;
1050 		case CTLTYPE_S8:
1051 		case CTLTYPE_U8:
1052 			size = sizeof(int8_t);
1053 			break;
1054 		case CTLTYPE_S16:
1055 		case CTLTYPE_U16:
1056 			size = sizeof(int16_t);
1057 			break;
1058 		case CTLTYPE_S32:
1059 		case CTLTYPE_U32:
1060 			size = sizeof(int32_t);
1061 			break;
1062 		case CTLTYPE_S64:
1063 		case CTLTYPE_U64:
1064 			size = sizeof(int64_t);
1065 			break;
1066 		case CTLTYPE_STRING:
1067 			MPASS(oidp->oid_arg2 > 0);
1068 			size = oidp->oid_arg2;
1069 			break;
1070 		default:
1071 			goto out;
1072 		}
1073 		vnet_restore_init(oidp->oid_arg1, size);
1074 	}
1075 out:
1076 	SYSCTL_WUNLOCK();
1077 }
1078 
1079 /*
1080  * Register the kernel's setenv / unsetenv events.
1081  */
1082 EVENTHANDLER_DEFINE(setenv, sysctl_setenv_vnet, NULL, EVENTHANDLER_PRI_ANY);
1083 EVENTHANDLER_DEFINE(unsetenv, sysctl_unsetenv_vnet, NULL, EVENTHANDLER_PRI_ANY);
1084 #endif
1085 
1086 /*
1087  * "Staff-functions"
1088  *
1089  * These functions implement a presently undocumented interface
1090  * used by the sysctl program to walk the tree, and get the type
1091  * so it can print the value.
1092  * This interface is under work and consideration, and should probably
1093  * be killed with a big axe by the first person who can find the time.
1094  * (be aware though, that the proper interface isn't as obvious as it
1095  * may seem, there are various conflicting requirements.
1096  *
1097  * {CTL_SYSCTL, CTL_SYSCTL_DEBUG}		printf the entire MIB-tree.
1098  * {CTL_SYSCTL, CTL_SYSCTL_NAME, ...}		return the name of the "..."
1099  *						OID.
1100  * {CTL_SYSCTL, CTL_SYSCTL_NEXT, ...}		return the next OID, honoring
1101  *						CTLFLAG_SKIP.
1102  * {CTL_SYSCTL, CTL_SYSCTL_NAME2OID}		return the OID of the name in
1103  *						"new"
1104  * {CTL_SYSCTL, CTL_SYSCTL_OIDFMT, ...}		return the kind & format info
1105  *						for the "..." OID.
1106  * {CTL_SYSCTL, CTL_SYSCTL_OIDDESCR, ...}	return the description of the
1107  *						"..." OID.
1108  * {CTL_SYSCTL, CTL_SYSCTL_OIDLABEL, ...}	return the aggregation label of
1109  *						the "..." OID.
1110  * {CTL_SYSCTL, CTL_SYSCTL_NEXTNOSKIP, ...}	return the next OID, ignoring
1111  *						CTLFLAG_SKIP.
1112  */
1113 
1114 #ifdef SYSCTL_DEBUG
1115 static void
1116 sysctl_sysctl_debug_dump_node(struct sysctl_oid_list *l, int i)
1117 {
1118 	int k;
1119 	struct sysctl_oid *oidp;
1120 
1121 	SYSCTL_ASSERT_LOCKED();
1122 	SYSCTL_FOREACH(oidp, l) {
1123 		for (k=0; k<i; k++)
1124 			printf(" ");
1125 
1126 		printf("%d %s ", oidp->oid_number, oidp->oid_name);
1127 
1128 		printf("%c%c",
1129 			oidp->oid_kind & CTLFLAG_RD ? 'R':' ',
1130 			oidp->oid_kind & CTLFLAG_WR ? 'W':' ');
1131 
1132 		if (oidp->oid_handler)
1133 			printf(" *Handler");
1134 
1135 		switch (oidp->oid_kind & CTLTYPE) {
1136 			case CTLTYPE_NODE:
1137 				printf(" Node\n");
1138 				if (!oidp->oid_handler) {
1139 					sysctl_sysctl_debug_dump_node(
1140 					    SYSCTL_CHILDREN(oidp), i + 2);
1141 				}
1142 				break;
1143 			case CTLTYPE_INT:    printf(" Int\n"); break;
1144 			case CTLTYPE_UINT:   printf(" u_int\n"); break;
1145 			case CTLTYPE_LONG:   printf(" Long\n"); break;
1146 			case CTLTYPE_ULONG:  printf(" u_long\n"); break;
1147 			case CTLTYPE_STRING: printf(" String\n"); break;
1148 			case CTLTYPE_S8:     printf(" int8_t\n"); break;
1149 			case CTLTYPE_S16:    printf(" int16_t\n"); break;
1150 			case CTLTYPE_S32:    printf(" int32_t\n"); break;
1151 			case CTLTYPE_S64:    printf(" int64_t\n"); break;
1152 			case CTLTYPE_U8:     printf(" uint8_t\n"); break;
1153 			case CTLTYPE_U16:    printf(" uint16_t\n"); break;
1154 			case CTLTYPE_U32:    printf(" uint32_t\n"); break;
1155 			case CTLTYPE_U64:    printf(" uint64_t\n"); break;
1156 			case CTLTYPE_OPAQUE: printf(" Opaque/struct\n"); break;
1157 			default:	     printf("\n");
1158 		}
1159 	}
1160 }
1161 
1162 static int
1163 sysctl_sysctl_debug(SYSCTL_HANDLER_ARGS)
1164 {
1165 	struct rm_priotracker tracker;
1166 	int error;
1167 
1168 	error = priv_check(req->td, PRIV_SYSCTL_DEBUG);
1169 	if (error)
1170 		return (error);
1171 	SYSCTL_RLOCK(&tracker);
1172 	sysctl_sysctl_debug_dump_node(&sysctl__children, 0);
1173 	SYSCTL_RUNLOCK(&tracker);
1174 	return (ENOENT);
1175 }
1176 
1177 SYSCTL_PROC(_sysctl, CTL_SYSCTL_DEBUG, debug, CTLTYPE_STRING | CTLFLAG_RD |
1178     CTLFLAG_MPSAFE, 0, 0, sysctl_sysctl_debug, "-", "");
1179 #endif
1180 
1181 static int
1182 sysctl_sysctl_name(SYSCTL_HANDLER_ARGS)
1183 {
1184 	int *name = (int *) arg1;
1185 	u_int namelen = arg2;
1186 	int error;
1187 	struct sysctl_oid *oid, key;
1188 	struct sysctl_oid_list *lsp = &sysctl__children, *lsp2;
1189 	struct rm_priotracker tracker;
1190 	char buf[10];
1191 
1192 	error = sysctl_wire_old_buffer(req, 0);
1193 	if (error)
1194 		return (error);
1195 
1196 	SYSCTL_RLOCK(&tracker);
1197 	while (namelen) {
1198 		if (!lsp) {
1199 			snprintf(buf,sizeof(buf),"%d",*name);
1200 			if (req->oldidx)
1201 				error = SYSCTL_OUT(req, ".", 1);
1202 			if (!error)
1203 				error = SYSCTL_OUT(req, buf, strlen(buf));
1204 			if (error)
1205 				goto out;
1206 			namelen--;
1207 			name++;
1208 			continue;
1209 		}
1210 		lsp2 = NULL;
1211 		key.oid_number = *name;
1212 		oid = RB_FIND(sysctl_oid_list, lsp, &key);
1213 		if (oid) {
1214 			if (req->oldidx)
1215 				error = SYSCTL_OUT(req, ".", 1);
1216 			if (!error)
1217 				error = SYSCTL_OUT(req, oid->oid_name,
1218 					strlen(oid->oid_name));
1219 			if (error)
1220 				goto out;
1221 
1222 			namelen--;
1223 			name++;
1224 
1225 			if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE &&
1226 				!oid->oid_handler)
1227 				lsp2 = SYSCTL_CHILDREN(oid);
1228 		}
1229 		lsp = lsp2;
1230 	}
1231 	error = SYSCTL_OUT(req, "", 1);
1232  out:
1233 	SYSCTL_RUNLOCK(&tracker);
1234 	return (error);
1235 }
1236 
1237 /*
1238  * XXXRW/JA: Shouldn't return name data for nodes that we don't permit in
1239  * capability mode.
1240  */
1241 static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NAME, name, CTLFLAG_RD |
1242     CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_name, "");
1243 
1244 enum sysctl_iter_action {
1245 	ITER_SIBLINGS,	/* Not matched, continue iterating siblings */
1246 	ITER_CHILDREN,	/* Node has children we need to iterate over them */
1247 	ITER_FOUND,	/* Matching node was found */
1248 };
1249 
1250 /*
1251  * Tries to find the next node for @name and @namelen.
1252  *
1253  * Returns next action to take.
1254  */
1255 static enum sysctl_iter_action
1256 sysctl_sysctl_next_node(struct sysctl_oid *oidp, int *name, unsigned int namelen,
1257     bool honor_skip)
1258 {
1259 
1260 	if ((oidp->oid_kind & CTLFLAG_DORMANT) != 0)
1261 		return (ITER_SIBLINGS);
1262 
1263 	if (honor_skip && (oidp->oid_kind & CTLFLAG_SKIP) != 0)
1264 		return (ITER_SIBLINGS);
1265 
1266 	if (namelen == 0) {
1267 		/*
1268 		 * We have reached a node with a full name match and are
1269 		 * looking for the next oid in its children.
1270 		 *
1271 		 * For CTL_SYSCTL_NEXTNOSKIP we are done.
1272 		 *
1273 		 * For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it
1274 		 * has a handler) and move on to the children.
1275 		 */
1276 		if (!honor_skip)
1277 			return (ITER_FOUND);
1278 		if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
1279 			return (ITER_FOUND);
1280 		/* If node does not have an iterator, treat it as leaf */
1281 		if (oidp->oid_handler)
1282 			return (ITER_FOUND);
1283 
1284 		/* Report oid as a node to iterate */
1285 		return (ITER_CHILDREN);
1286 	}
1287 
1288 	/*
1289 	 * No match yet. Continue seeking the given name.
1290 	 *
1291 	 * We are iterating in order by oid_number, so skip oids lower
1292 	 * than the one we are looking for.
1293 	 *
1294 	 * When the current oid_number is higher than the one we seek,
1295 	 * that means we have reached the next oid in the sequence and
1296 	 * should return it.
1297 	 *
1298 	 * If the oid_number matches the name at this level then we
1299 	 * have to find a node to continue searching at the next level.
1300 	 */
1301 	if (oidp->oid_number < *name)
1302 		return (ITER_SIBLINGS);
1303 	if (oidp->oid_number > *name) {
1304 		/*
1305 		 * We have reached the next oid.
1306 		 *
1307 		 * For CTL_SYSCTL_NEXTNOSKIP we are done.
1308 		 *
1309 		 * For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it
1310 		 * has a handler) and move on to the children.
1311 		 */
1312 		if (!honor_skip)
1313 			return (ITER_FOUND);
1314 		if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
1315 			return (ITER_FOUND);
1316 		/* If node does not have an iterator, treat it as leaf */
1317 		if (oidp->oid_handler)
1318 			return (ITER_FOUND);
1319 		return (ITER_CHILDREN);
1320 	}
1321 
1322 	/* match at a current level */
1323 	if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
1324 		return (ITER_SIBLINGS);
1325 	if (oidp->oid_handler)
1326 		return (ITER_SIBLINGS);
1327 
1328 	return (ITER_CHILDREN);
1329 }
1330 
1331 /*
1332  * Recursively walk the sysctl subtree at lsp until we find the given name.
1333  * Returns true and fills in next oid data in @next and @len if oid is found.
1334  */
1335 static bool
1336 sysctl_sysctl_next_action(struct sysctl_oid_list *lsp, int *name, u_int namelen,
1337     int *next, int *len, int level, bool honor_skip)
1338 {
1339 	struct sysctl_oid_list *next_lsp;
1340 	struct sysctl_oid *oidp = NULL, key;
1341 	bool success = false;
1342 	enum sysctl_iter_action action;
1343 
1344 	SYSCTL_ASSERT_LOCKED();
1345 	/*
1346 	 * Start the search at the requested oid.  But if not found, then scan
1347 	 * through all children.
1348 	 */
1349 	if (namelen > 0) {
1350 		key.oid_number = *name;
1351 		oidp = RB_FIND(sysctl_oid_list, lsp, &key);
1352 	}
1353 	if (!oidp)
1354 		oidp = RB_MIN(sysctl_oid_list, lsp);
1355 	for(; oidp != NULL; oidp = RB_NEXT(sysctl_oid_list, lsp, oidp)) {
1356 		action = sysctl_sysctl_next_node(oidp, name, namelen,
1357 		    honor_skip);
1358 		if (action == ITER_SIBLINGS)
1359 			continue;
1360 		if (action == ITER_FOUND) {
1361 			success = true;
1362 			break;
1363 		}
1364 		KASSERT((action== ITER_CHILDREN), ("ret(%d)!=ITER_CHILDREN", action));
1365 
1366 		next_lsp = SYSCTL_CHILDREN(oidp);
1367 		if (namelen == 0) {
1368 			success = sysctl_sysctl_next_action(next_lsp, NULL, 0,
1369 			    next + 1, len, level + 1, honor_skip);
1370 		} else {
1371 			success = sysctl_sysctl_next_action(next_lsp, name + 1,
1372 			    namelen - 1, next + 1, len, level + 1, honor_skip);
1373 			if (!success) {
1374 
1375 				/*
1376 				 * We maintain the invariant that current node oid
1377 				 * is >= the oid provided in @name.
1378 				 * As there are no usable children at this node,
1379 				 *  current node oid is strictly > than the requested
1380 				 *  oid.
1381 				 * Hence, reduce namelen to 0 to allow for picking first
1382 				 *  nodes/leafs in the next node in list.
1383 				 */
1384 				namelen = 0;
1385 			}
1386 		}
1387 		if (success)
1388 			break;
1389 	}
1390 
1391 	if (success) {
1392 		*next = oidp->oid_number;
1393 		if (level > *len)
1394 			*len = level;
1395 	}
1396 
1397 	return (success);
1398 }
1399 
1400 static int
1401 sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
1402 {
1403 	int *name = (int *) arg1;
1404 	u_int namelen = arg2;
1405 	int len, error;
1406 	bool success;
1407 	struct sysctl_oid_list *lsp = &sysctl__children;
1408 	struct rm_priotracker tracker;
1409 	int next[CTL_MAXNAME];
1410 
1411 	len = 0;
1412 	SYSCTL_RLOCK(&tracker);
1413 	success = sysctl_sysctl_next_action(lsp, name, namelen, next, &len, 1,
1414 	    oidp->oid_number == CTL_SYSCTL_NEXT);
1415 	SYSCTL_RUNLOCK(&tracker);
1416 	if (!success)
1417 		return (ENOENT);
1418 	error = SYSCTL_OUT(req, next, len * sizeof (int));
1419 	return (error);
1420 }
1421 
1422 /*
1423  * XXXRW/JA: Shouldn't return next data for nodes that we don't permit in
1424  * capability mode.
1425  */
1426 static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NEXT, next, CTLFLAG_RD |
1427     CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_next, "");
1428 
1429 static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NEXTNOSKIP, nextnoskip, CTLFLAG_RD |
1430     CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_next, "");
1431 
1432 static int
1433 name2oid(const char *name, int *oid, int *len, struct sysctl_oid **oidpp)
1434 {
1435 	struct sysctl_oid *oidp;
1436 	struct sysctl_oid_list *lsp = &sysctl__children;
1437 	const char *n;
1438 
1439 	SYSCTL_ASSERT_LOCKED();
1440 
1441 	for (*len = 0; *len < CTL_MAXNAME;) {
1442 		n = strchrnul(name, '.');
1443 		oidp = sysctl_find_oidnamelen(name, n - name, lsp);
1444 		if (oidp == NULL)
1445 			return (ENOENT);
1446 		*oid++ = oidp->oid_number;
1447 		(*len)++;
1448 
1449 		name = n;
1450 		if (*name == '.')
1451 			name++;
1452 		if (*name == '\0') {
1453 			if (oidpp)
1454 				*oidpp = oidp;
1455 			return (0);
1456 		}
1457 
1458 		if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
1459 			break;
1460 
1461 		if (oidp->oid_handler)
1462 			break;
1463 
1464 		lsp = SYSCTL_CHILDREN(oidp);
1465 	}
1466 	return (ENOENT);
1467 }
1468 
1469 static int
1470 sysctl_sysctl_name2oid(SYSCTL_HANDLER_ARGS)
1471 {
1472 	char *p;
1473 	int error, oid[CTL_MAXNAME], len = 0;
1474 	struct sysctl_oid *op = NULL;
1475 	struct rm_priotracker tracker;
1476 	char buf[32];
1477 
1478 	if (!req->newlen)
1479 		return (ENOENT);
1480 	if (req->newlen >= MAXPATHLEN)	/* XXX arbitrary, undocumented */
1481 		return (ENAMETOOLONG);
1482 
1483 	p = buf;
1484 	if (req->newlen >= sizeof(buf))
1485 		p = malloc(req->newlen+1, M_SYSCTL, M_WAITOK);
1486 
1487 	error = SYSCTL_IN(req, p, req->newlen);
1488 	if (error) {
1489 		if (p != buf)
1490 			free(p, M_SYSCTL);
1491 		return (error);
1492 	}
1493 
1494 	p [req->newlen] = '\0';
1495 
1496 	SYSCTL_RLOCK(&tracker);
1497 	error = name2oid(p, oid, &len, &op);
1498 	SYSCTL_RUNLOCK(&tracker);
1499 
1500 	if (p != buf)
1501 		free(p, M_SYSCTL);
1502 
1503 	if (error)
1504 		return (error);
1505 
1506 	error = SYSCTL_OUT(req, oid, len * sizeof *oid);
1507 	return (error);
1508 }
1509 
1510 /*
1511  * XXXRW/JA: Shouldn't return name2oid data for nodes that we don't permit in
1512  * capability mode.
1513  */
1514 SYSCTL_PROC(_sysctl, CTL_SYSCTL_NAME2OID, name2oid, CTLTYPE_INT | CTLFLAG_RW |
1515     CTLFLAG_ANYBODY | CTLFLAG_MPSAFE | CTLFLAG_CAPRW, 0, 0,
1516     sysctl_sysctl_name2oid, "I", "");
1517 
1518 static int
1519 sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
1520 {
1521 	struct sysctl_oid *oid;
1522 	struct rm_priotracker tracker;
1523 	int error;
1524 
1525 	error = sysctl_wire_old_buffer(req, 0);
1526 	if (error)
1527 		return (error);
1528 
1529 	SYSCTL_RLOCK(&tracker);
1530 	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
1531 	if (error)
1532 		goto out;
1533 
1534 	if (oid->oid_fmt == NULL) {
1535 		error = ENOENT;
1536 		goto out;
1537 	}
1538 	error = SYSCTL_OUT(req, &oid->oid_kind, sizeof(oid->oid_kind));
1539 	if (error)
1540 		goto out;
1541 	error = SYSCTL_OUT(req, oid->oid_fmt, strlen(oid->oid_fmt) + 1);
1542  out:
1543 	SYSCTL_RUNLOCK(&tracker);
1544 	return (error);
1545 }
1546 
1547 static SYSCTL_NODE(_sysctl, CTL_SYSCTL_OIDFMT, oidfmt, CTLFLAG_RD |
1548     CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_oidfmt, "");
1549 
1550 static int
1551 sysctl_sysctl_oiddescr(SYSCTL_HANDLER_ARGS)
1552 {
1553 	struct sysctl_oid *oid;
1554 	struct rm_priotracker tracker;
1555 	int error;
1556 
1557 	error = sysctl_wire_old_buffer(req, 0);
1558 	if (error)
1559 		return (error);
1560 
1561 	SYSCTL_RLOCK(&tracker);
1562 	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
1563 	if (error)
1564 		goto out;
1565 
1566 	if (oid->oid_descr == NULL) {
1567 		error = ENOENT;
1568 		goto out;
1569 	}
1570 	error = SYSCTL_OUT(req, oid->oid_descr, strlen(oid->oid_descr) + 1);
1571  out:
1572 	SYSCTL_RUNLOCK(&tracker);
1573 	return (error);
1574 }
1575 
1576 static SYSCTL_NODE(_sysctl, CTL_SYSCTL_OIDDESCR, oiddescr, CTLFLAG_RD |
1577     CTLFLAG_MPSAFE|CTLFLAG_CAPRD, sysctl_sysctl_oiddescr, "");
1578 
1579 static int
1580 sysctl_sysctl_oidlabel(SYSCTL_HANDLER_ARGS)
1581 {
1582 	struct sysctl_oid *oid;
1583 	struct rm_priotracker tracker;
1584 	int error;
1585 
1586 	error = sysctl_wire_old_buffer(req, 0);
1587 	if (error)
1588 		return (error);
1589 
1590 	SYSCTL_RLOCK(&tracker);
1591 	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
1592 	if (error)
1593 		goto out;
1594 
1595 	if (oid->oid_label == NULL) {
1596 		error = ENOENT;
1597 		goto out;
1598 	}
1599 	error = SYSCTL_OUT(req, oid->oid_label, strlen(oid->oid_label) + 1);
1600  out:
1601 	SYSCTL_RUNLOCK(&tracker);
1602 	return (error);
1603 }
1604 
1605 static SYSCTL_NODE(_sysctl, CTL_SYSCTL_OIDLABEL, oidlabel, CTLFLAG_RD |
1606     CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_oidlabel, "");
1607 
1608 /*
1609  * Default "handler" functions.
1610  */
1611 
1612 /*
1613  * Handle a bool.
1614  * Two cases:
1615  *     a variable:  point arg1 at it.
1616  *     a constant:  pass it in arg2.
1617  */
1618 
1619 int
1620 sysctl_handle_bool(SYSCTL_HANDLER_ARGS)
1621 {
1622 	uint8_t temp;
1623 	int error;
1624 
1625 	/*
1626 	 * Attempt to get a coherent snapshot by making a copy of the data.
1627 	 */
1628 	if (arg1)
1629 		temp = *(bool *)arg1 ? 1 : 0;
1630 	else
1631 		temp = arg2 ? 1 : 0;
1632 
1633 	error = SYSCTL_OUT(req, &temp, sizeof(temp));
1634 	if (error || !req->newptr)
1635 		return (error);
1636 
1637 	if (!arg1)
1638 		error = EPERM;
1639 	else {
1640 		error = SYSCTL_IN(req, &temp, sizeof(temp));
1641 		if (!error)
1642 			*(bool *)arg1 = temp ? 1 : 0;
1643 	}
1644 	return (error);
1645 }
1646 
1647 /*
1648  * Handle an int8_t, signed or unsigned.
1649  * Two cases:
1650  *     a variable:  point arg1 at it.
1651  *     a constant:  pass it in arg2.
1652  */
1653 
1654 int
1655 sysctl_handle_8(SYSCTL_HANDLER_ARGS)
1656 {
1657 	int8_t tmpout;
1658 	int error = 0;
1659 
1660 	/*
1661 	 * Attempt to get a coherent snapshot by making a copy of the data.
1662 	 */
1663 	if (arg1)
1664 		tmpout = *(int8_t *)arg1;
1665 	else
1666 		tmpout = arg2;
1667 	error = SYSCTL_OUT(req, &tmpout, sizeof(tmpout));
1668 
1669 	if (error || !req->newptr)
1670 		return (error);
1671 
1672 	if (!arg1)
1673 		error = EPERM;
1674 	else
1675 		error = SYSCTL_IN(req, arg1, sizeof(tmpout));
1676 	return (error);
1677 }
1678 
1679 /*
1680  * Handle an int16_t, signed or unsigned.
1681  * Two cases:
1682  *     a variable:  point arg1 at it.
1683  *     a constant:  pass it in arg2.
1684  */
1685 
1686 int
1687 sysctl_handle_16(SYSCTL_HANDLER_ARGS)
1688 {
1689 	int16_t tmpout;
1690 	int error = 0;
1691 
1692 	/*
1693 	 * Attempt to get a coherent snapshot by making a copy of the data.
1694 	 */
1695 	if (arg1)
1696 		tmpout = *(int16_t *)arg1;
1697 	else
1698 		tmpout = arg2;
1699 	error = SYSCTL_OUT(req, &tmpout, sizeof(tmpout));
1700 
1701 	if (error || !req->newptr)
1702 		return (error);
1703 
1704 	if (!arg1)
1705 		error = EPERM;
1706 	else
1707 		error = SYSCTL_IN(req, arg1, sizeof(tmpout));
1708 	return (error);
1709 }
1710 
1711 /*
1712  * Handle an int32_t, signed or unsigned.
1713  * Two cases:
1714  *     a variable:  point arg1 at it.
1715  *     a constant:  pass it in arg2.
1716  */
1717 
1718 int
1719 sysctl_handle_32(SYSCTL_HANDLER_ARGS)
1720 {
1721 	int32_t tmpout;
1722 	int error = 0;
1723 
1724 	/*
1725 	 * Attempt to get a coherent snapshot by making a copy of the data.
1726 	 */
1727 	if (arg1)
1728 		tmpout = *(int32_t *)arg1;
1729 	else
1730 		tmpout = arg2;
1731 	error = SYSCTL_OUT(req, &tmpout, sizeof(tmpout));
1732 
1733 	if (error || !req->newptr)
1734 		return (error);
1735 
1736 	if (!arg1)
1737 		error = EPERM;
1738 	else
1739 		error = SYSCTL_IN(req, arg1, sizeof(tmpout));
1740 	return (error);
1741 }
1742 
1743 /*
1744  * Handle an int, signed or unsigned.
1745  * Two cases:
1746  *     a variable:  point arg1 at it.
1747  *     a constant:  pass it in arg2.
1748  */
1749 
1750 int
1751 sysctl_handle_int(SYSCTL_HANDLER_ARGS)
1752 {
1753 	int tmpout, error = 0;
1754 
1755 	/*
1756 	 * Attempt to get a coherent snapshot by making a copy of the data.
1757 	 */
1758 	if (arg1)
1759 		tmpout = *(int *)arg1;
1760 	else
1761 		tmpout = arg2;
1762 	error = SYSCTL_OUT(req, &tmpout, sizeof(int));
1763 
1764 	if (error || !req->newptr)
1765 		return (error);
1766 
1767 	if (!arg1)
1768 		error = EPERM;
1769 	else
1770 		error = SYSCTL_IN(req, arg1, sizeof(int));
1771 	return (error);
1772 }
1773 
1774 /*
1775  * Based on sysctl_handle_int() convert milliseconds into ticks.
1776  * Note: this is used by TCP.
1777  */
1778 
1779 int
1780 sysctl_msec_to_ticks(SYSCTL_HANDLER_ARGS)
1781 {
1782 	int error, s, tt;
1783 
1784 	tt = *(int *)arg1;
1785 	s = (int)((int64_t)tt * 1000 / hz);
1786 
1787 	error = sysctl_handle_int(oidp, &s, 0, req);
1788 	if (error || !req->newptr)
1789 		return (error);
1790 
1791 	tt = (int)((int64_t)s * hz / 1000);
1792 	if (tt < 1)
1793 		return (EINVAL);
1794 
1795 	*(int *)arg1 = tt;
1796 	return (0);
1797 }
1798 
1799 /*
1800  * Handle a long, signed or unsigned.
1801  * Two cases:
1802  *     a variable:  point arg1 at it.
1803  *     a constant:  pass it in arg2.
1804  */
1805 
1806 int
1807 sysctl_handle_long(SYSCTL_HANDLER_ARGS)
1808 {
1809 	int error = 0;
1810 	long tmplong;
1811 #ifdef SCTL_MASK32
1812 	int tmpint;
1813 #endif
1814 
1815 	/*
1816 	 * Attempt to get a coherent snapshot by making a copy of the data.
1817 	 */
1818 	if (arg1)
1819 		tmplong = *(long *)arg1;
1820 	else
1821 		tmplong = arg2;
1822 #ifdef SCTL_MASK32
1823 	if (req->flags & SCTL_MASK32) {
1824 		tmpint = tmplong;
1825 		error = SYSCTL_OUT(req, &tmpint, sizeof(int));
1826 	} else
1827 #endif
1828 		error = SYSCTL_OUT(req, &tmplong, sizeof(long));
1829 
1830 	if (error || !req->newptr)
1831 		return (error);
1832 
1833 	if (!arg1)
1834 		error = EPERM;
1835 #ifdef SCTL_MASK32
1836 	else if (req->flags & SCTL_MASK32) {
1837 		error = SYSCTL_IN(req, &tmpint, sizeof(int));
1838 		*(long *)arg1 = (long)tmpint;
1839 	}
1840 #endif
1841 	else
1842 		error = SYSCTL_IN(req, arg1, sizeof(long));
1843 	return (error);
1844 }
1845 
1846 /*
1847  * Handle a 64 bit int, signed or unsigned.
1848  * Two cases:
1849  *     a variable:  point arg1 at it.
1850  *     a constant:  pass it in arg2.
1851  */
1852 int
1853 sysctl_handle_64(SYSCTL_HANDLER_ARGS)
1854 {
1855 	int error = 0;
1856 	uint64_t tmpout;
1857 
1858 	/*
1859 	 * Attempt to get a coherent snapshot by making a copy of the data.
1860 	 */
1861 	if (arg1)
1862 		tmpout = *(uint64_t *)arg1;
1863 	else
1864 		tmpout = arg2;
1865 	error = SYSCTL_OUT(req, &tmpout, sizeof(uint64_t));
1866 
1867 	if (error || !req->newptr)
1868 		return (error);
1869 
1870 	if (!arg1)
1871 		error = EPERM;
1872 	else
1873 		error = SYSCTL_IN(req, arg1, sizeof(uint64_t));
1874 	return (error);
1875 }
1876 
1877 /*
1878  * Handle our generic '\0' terminated 'C' string.
1879  * Two cases:
1880  * 	a variable string:  point arg1 at it, arg2 is max length.
1881  * 	a constant string:  point arg1 at it, arg2 is zero.
1882  */
1883 
1884 int
1885 sysctl_handle_string(SYSCTL_HANDLER_ARGS)
1886 {
1887 	char *tmparg;
1888 	size_t outlen;
1889 	int error = 0, ro_string = 0;
1890 
1891 	/*
1892 	 * If the sysctl isn't writable and isn't a preallocated tunable that
1893 	 * can be modified by kenv(2), microoptimise and treat it as a
1894 	 * read-only string.
1895 	 * A zero-length buffer indicates a fixed size read-only
1896 	 * string.  In ddb, don't worry about trying to make a malloced
1897 	 * snapshot.
1898 	 */
1899 	if ((oidp->oid_kind & (CTLFLAG_WR | CTLFLAG_TUN)) == 0 ||
1900 	    arg2 == 0 || kdb_active) {
1901 		arg2 = strlen((char *)arg1) + 1;
1902 		ro_string = 1;
1903 	}
1904 
1905 	if (req->oldptr != NULL) {
1906 		if (ro_string) {
1907 			tmparg = arg1;
1908 			outlen = strlen(tmparg) + 1;
1909 		} else {
1910 			tmparg = malloc(arg2, M_SYSCTLTMP, M_WAITOK);
1911 			sx_slock(&sysctlstringlock);
1912 			memcpy(tmparg, arg1, arg2);
1913 			sx_sunlock(&sysctlstringlock);
1914 			outlen = strlen(tmparg) + 1;
1915 		}
1916 
1917 		error = SYSCTL_OUT(req, tmparg, outlen);
1918 
1919 		if (!ro_string)
1920 			free(tmparg, M_SYSCTLTMP);
1921 	} else {
1922 		if (!ro_string)
1923 			sx_slock(&sysctlstringlock);
1924 		outlen = strlen((char *)arg1) + 1;
1925 		if (!ro_string)
1926 			sx_sunlock(&sysctlstringlock);
1927 		error = SYSCTL_OUT(req, NULL, outlen);
1928 	}
1929 	if (error || !req->newptr)
1930 		return (error);
1931 
1932 	if (req->newlen - req->newidx >= arg2 ||
1933 	    req->newlen - req->newidx < 0) {
1934 		error = EINVAL;
1935 	} else if (req->newlen - req->newidx == 0) {
1936 		sx_xlock(&sysctlstringlock);
1937 		((char *)arg1)[0] = '\0';
1938 		sx_xunlock(&sysctlstringlock);
1939 	} else if (req->newfunc == sysctl_new_kernel) {
1940 		arg2 = req->newlen - req->newidx;
1941 		sx_xlock(&sysctlstringlock);
1942 		error = SYSCTL_IN(req, arg1, arg2);
1943 		if (error == 0) {
1944 			((char *)arg1)[arg2] = '\0';
1945 			req->newidx += arg2;
1946 		}
1947 		sx_xunlock(&sysctlstringlock);
1948 	} else {
1949 		arg2 = req->newlen - req->newidx;
1950 		tmparg = malloc(arg2, M_SYSCTLTMP, M_WAITOK);
1951 
1952 		error = SYSCTL_IN(req, tmparg, arg2);
1953 		if (error) {
1954 			free(tmparg, M_SYSCTLTMP);
1955 			return (error);
1956 		}
1957 
1958 		sx_xlock(&sysctlstringlock);
1959 		memcpy(arg1, tmparg, arg2);
1960 		((char *)arg1)[arg2] = '\0';
1961 		sx_xunlock(&sysctlstringlock);
1962 		free(tmparg, M_SYSCTLTMP);
1963 		req->newidx += arg2;
1964 	}
1965 	return (error);
1966 }
1967 
1968 /*
1969  * Handle any kind of opaque data.
1970  * arg1 points to it, arg2 is the size.
1971  */
1972 
1973 int
1974 sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
1975 {
1976 	int error, tries;
1977 	u_int generation;
1978 	struct sysctl_req req2;
1979 
1980 	/*
1981 	 * Attempt to get a coherent snapshot, by using the thread
1982 	 * pre-emption counter updated from within mi_switch() to
1983 	 * determine if we were pre-empted during a bcopy() or
1984 	 * copyout(). Make 3 attempts at doing this before giving up.
1985 	 * If we encounter an error, stop immediately.
1986 	 */
1987 	tries = 0;
1988 	req2 = *req;
1989 retry:
1990 	generation = curthread->td_generation;
1991 	error = SYSCTL_OUT(req, arg1, arg2);
1992 	if (error)
1993 		return (error);
1994 	tries++;
1995 	if (generation != curthread->td_generation && tries < 3) {
1996 		*req = req2;
1997 		goto retry;
1998 	}
1999 
2000 	error = SYSCTL_IN(req, arg1, arg2);
2001 
2002 	return (error);
2003 }
2004 
2005 /*
2006  * Based on sysctl_handle_64() convert microseconds to a sbintime.
2007  */
2008 int
2009 sysctl_usec_to_sbintime(SYSCTL_HANDLER_ARGS)
2010 {
2011 	int error;
2012 	int64_t usec;
2013 
2014 	usec = sbttous(*(sbintime_t *)arg1);
2015 
2016 	error = sysctl_handle_64(oidp, &usec, 0, req);
2017 	if (error || !req->newptr)
2018 		return (error);
2019 
2020 	*(sbintime_t *)arg1 = ustosbt(usec);
2021 
2022 	return (0);
2023 }
2024 
2025 /*
2026  * Based on sysctl_handle_64() convert milliseconds to a sbintime.
2027  */
2028 int
2029 sysctl_msec_to_sbintime(SYSCTL_HANDLER_ARGS)
2030 {
2031 	int error;
2032 	int64_t msec;
2033 
2034 	msec = sbttoms(*(sbintime_t *)arg1);
2035 
2036 	error = sysctl_handle_64(oidp, &msec, 0, req);
2037 	if (error || !req->newptr)
2038 		return (error);
2039 
2040 	*(sbintime_t *)arg1 = mstosbt(msec);
2041 
2042 	return (0);
2043 }
2044 
2045 /*
2046  * Convert seconds to a struct timeval.  Intended for use with
2047  * intervals and thus does not permit negative seconds.
2048  */
2049 int
2050 sysctl_sec_to_timeval(SYSCTL_HANDLER_ARGS)
2051 {
2052 	struct timeval *tv;
2053 	int error, secs;
2054 
2055 	tv = arg1;
2056 	secs = tv->tv_sec;
2057 
2058 	error = sysctl_handle_int(oidp, &secs, 0, req);
2059 	if (error || req->newptr == NULL)
2060 		return (error);
2061 
2062 	if (secs < 0)
2063 		return (EINVAL);
2064 	tv->tv_sec = secs;
2065 
2066 	return (0);
2067 }
2068 
2069 /*
2070  * Transfer functions to/from kernel space.
2071  * XXX: rather untested at this point
2072  */
2073 static int
2074 sysctl_old_kernel(struct sysctl_req *req, const void *p, size_t l)
2075 {
2076 	size_t i = 0;
2077 
2078 	if (req->oldptr) {
2079 		i = l;
2080 		if (req->oldlen <= req->oldidx)
2081 			i = 0;
2082 		else
2083 			if (i > req->oldlen - req->oldidx)
2084 				i = req->oldlen - req->oldidx;
2085 		if (i > 0)
2086 			bcopy(p, (char *)req->oldptr + req->oldidx, i);
2087 	}
2088 	req->oldidx += l;
2089 	if (req->oldptr && i != l)
2090 		return (ENOMEM);
2091 	return (0);
2092 }
2093 
2094 static int
2095 sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l)
2096 {
2097 	if (!req->newptr)
2098 		return (0);
2099 	if (req->newlen - req->newidx < l)
2100 		return (EINVAL);
2101 	bcopy((const char *)req->newptr + req->newidx, p, l);
2102 	req->newidx += l;
2103 	return (0);
2104 }
2105 
2106 int
2107 kernel_sysctl(struct thread *td, int *name, u_int namelen, void *old,
2108     size_t *oldlenp, void *new, size_t newlen, size_t *retval, int flags)
2109 {
2110 	int error = 0;
2111 	struct sysctl_req req;
2112 
2113 	bzero(&req, sizeof req);
2114 
2115 	req.td = td;
2116 	req.flags = flags;
2117 
2118 	if (oldlenp) {
2119 		req.oldlen = *oldlenp;
2120 	}
2121 	req.validlen = req.oldlen;
2122 
2123 	if (old) {
2124 		req.oldptr= old;
2125 	}
2126 
2127 	if (new != NULL) {
2128 		req.newlen = newlen;
2129 		req.newptr = new;
2130 	}
2131 
2132 	req.oldfunc = sysctl_old_kernel;
2133 	req.newfunc = sysctl_new_kernel;
2134 	req.lock = REQ_UNWIRED;
2135 
2136 	error = sysctl_root(0, name, namelen, &req);
2137 
2138 	if (req.lock == REQ_WIRED && req.validlen > 0)
2139 		vsunlock(req.oldptr, req.validlen);
2140 
2141 	if (error && error != ENOMEM)
2142 		return (error);
2143 
2144 	if (retval) {
2145 		if (req.oldptr && req.oldidx > req.validlen)
2146 			*retval = req.validlen;
2147 		else
2148 			*retval = req.oldidx;
2149 	}
2150 	return (error);
2151 }
2152 
2153 int
2154 kernel_sysctlbyname(struct thread *td, char *name, void *old, size_t *oldlenp,
2155     void *new, size_t newlen, size_t *retval, int flags)
2156 {
2157         int oid[CTL_MAXNAME];
2158         size_t oidlen, plen;
2159 	int error;
2160 
2161 	oid[0] = CTL_SYSCTL;
2162 	oid[1] = CTL_SYSCTL_NAME2OID;
2163 	oidlen = sizeof(oid);
2164 
2165 	error = kernel_sysctl(td, oid, 2, oid, &oidlen,
2166 	    (void *)name, strlen(name), &plen, flags);
2167 	if (error)
2168 		return (error);
2169 
2170 	error = kernel_sysctl(td, oid, plen / sizeof(int), old, oldlenp,
2171 	    new, newlen, retval, flags);
2172 	return (error);
2173 }
2174 
2175 /*
2176  * Transfer function to/from user space.
2177  */
2178 static int
2179 sysctl_old_user(struct sysctl_req *req, const void *p, size_t l)
2180 {
2181 	size_t i, len, origidx;
2182 	int error;
2183 
2184 	origidx = req->oldidx;
2185 	req->oldidx += l;
2186 	if (req->oldptr == NULL)
2187 		return (0);
2188 	/*
2189 	 * If we have not wired the user supplied buffer and we are currently
2190 	 * holding locks, drop a witness warning, as it's possible that
2191 	 * write operations to the user page can sleep.
2192 	 */
2193 	if (req->lock != REQ_WIRED)
2194 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
2195 		    "sysctl_old_user()");
2196 	i = l;
2197 	len = req->validlen;
2198 	if (len <= origidx)
2199 		i = 0;
2200 	else {
2201 		if (i > len - origidx)
2202 			i = len - origidx;
2203 		if (req->lock == REQ_WIRED) {
2204 			error = copyout_nofault(p, (char *)req->oldptr +
2205 			    origidx, i);
2206 		} else
2207 			error = copyout(p, (char *)req->oldptr + origidx, i);
2208 		if (error != 0)
2209 			return (error);
2210 	}
2211 	if (i < l)
2212 		return (ENOMEM);
2213 	return (0);
2214 }
2215 
2216 static int
2217 sysctl_new_user(struct sysctl_req *req, void *p, size_t l)
2218 {
2219 	int error;
2220 
2221 	if (!req->newptr)
2222 		return (0);
2223 	if (req->newlen - req->newidx < l)
2224 		return (EINVAL);
2225 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
2226 	    "sysctl_new_user()");
2227 	error = copyin((const char *)req->newptr + req->newidx, p, l);
2228 	req->newidx += l;
2229 	return (error);
2230 }
2231 
2232 /*
2233  * Wire the user space destination buffer.  If set to a value greater than
2234  * zero, the len parameter limits the maximum amount of wired memory.
2235  */
2236 int
2237 sysctl_wire_old_buffer(struct sysctl_req *req, size_t len)
2238 {
2239 	int ret;
2240 	size_t wiredlen;
2241 
2242 	wiredlen = (len > 0 && len < req->oldlen) ? len : req->oldlen;
2243 	ret = 0;
2244 	if (req->lock != REQ_WIRED && req->oldptr &&
2245 	    req->oldfunc == sysctl_old_user) {
2246 		if (wiredlen != 0) {
2247 			ret = vslock(req->oldptr, wiredlen);
2248 			if (ret != 0) {
2249 				if (ret != ENOMEM)
2250 					return (ret);
2251 				wiredlen = 0;
2252 			}
2253 		}
2254 		req->lock = REQ_WIRED;
2255 		req->validlen = wiredlen;
2256 	}
2257 	return (0);
2258 }
2259 
2260 int
2261 sysctl_find_oid(int *name, u_int namelen, struct sysctl_oid **noid,
2262     int *nindx, struct sysctl_req *req)
2263 {
2264 	struct sysctl_oid_list *lsp;
2265 	struct sysctl_oid *oid;
2266 	struct sysctl_oid key;
2267 	int indx;
2268 
2269 	SYSCTL_ASSERT_LOCKED();
2270 	lsp = &sysctl__children;
2271 	indx = 0;
2272 	while (indx < CTL_MAXNAME) {
2273 		key.oid_number = name[indx];
2274 		oid = RB_FIND(sysctl_oid_list, lsp, &key);
2275 		if (oid == NULL)
2276 			return (ENOENT);
2277 
2278 		indx++;
2279 		if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
2280 			if (oid->oid_handler != NULL || indx == namelen) {
2281 				*noid = oid;
2282 				if (nindx != NULL)
2283 					*nindx = indx;
2284 				KASSERT((oid->oid_kind & CTLFLAG_DYING) == 0,
2285 				    ("%s found DYING node %p", __func__, oid));
2286 				return (0);
2287 			}
2288 			lsp = SYSCTL_CHILDREN(oid);
2289 		} else if (indx == namelen) {
2290 			if ((oid->oid_kind & CTLFLAG_DORMANT) != 0)
2291 				return (ENOENT);
2292 			*noid = oid;
2293 			if (nindx != NULL)
2294 				*nindx = indx;
2295 			KASSERT((oid->oid_kind & CTLFLAG_DYING) == 0,
2296 			    ("%s found DYING node %p", __func__, oid));
2297 			return (0);
2298 		} else {
2299 			return (ENOTDIR);
2300 		}
2301 	}
2302 	return (ENOENT);
2303 }
2304 
2305 /*
2306  * Traverse our tree, and find the right node, execute whatever it points
2307  * to, and return the resulting error code.
2308  */
2309 
2310 static int
2311 sysctl_root(SYSCTL_HANDLER_ARGS)
2312 {
2313 	struct sysctl_oid *oid;
2314 	struct rm_priotracker tracker;
2315 	int error, indx, lvl;
2316 
2317 	SYSCTL_RLOCK(&tracker);
2318 
2319 	error = sysctl_find_oid(arg1, arg2, &oid, &indx, req);
2320 	if (error)
2321 		goto out;
2322 
2323 	if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
2324 		/*
2325 		 * You can't call a sysctl when it's a node, but has
2326 		 * no handler.  Inform the user that it's a node.
2327 		 * The indx may or may not be the same as namelen.
2328 		 */
2329 		if (oid->oid_handler == NULL) {
2330 			error = EISDIR;
2331 			goto out;
2332 		}
2333 	}
2334 
2335 	/* Is this sysctl writable? */
2336 	if (req->newptr && !(oid->oid_kind & CTLFLAG_WR)) {
2337 		error = EPERM;
2338 		goto out;
2339 	}
2340 
2341 	KASSERT(req->td != NULL, ("sysctl_root(): req->td == NULL"));
2342 
2343 #ifdef CAPABILITY_MODE
2344 	/*
2345 	 * If the process is in capability mode, then don't permit reading or
2346 	 * writing unless specifically granted for the node.
2347 	 */
2348 	if (IN_CAPABILITY_MODE(req->td)) {
2349 		if ((req->oldptr && !(oid->oid_kind & CTLFLAG_CAPRD)) ||
2350 		    (req->newptr && !(oid->oid_kind & CTLFLAG_CAPWR))) {
2351 			error = EPERM;
2352 			goto out;
2353 		}
2354 	}
2355 #endif
2356 
2357 	/* Is this sysctl sensitive to securelevels? */
2358 	if (req->newptr && (oid->oid_kind & CTLFLAG_SECURE)) {
2359 		lvl = (oid->oid_kind & CTLMASK_SECURE) >> CTLSHIFT_SECURE;
2360 		error = securelevel_gt(req->td->td_ucred, lvl);
2361 		if (error)
2362 			goto out;
2363 	}
2364 
2365 	/* Is this sysctl writable by only privileged users? */
2366 	if (req->newptr && !(oid->oid_kind & CTLFLAG_ANYBODY)) {
2367 		int priv;
2368 
2369 		if (oid->oid_kind & CTLFLAG_PRISON)
2370 			priv = PRIV_SYSCTL_WRITEJAIL;
2371 #ifdef VIMAGE
2372 		else if ((oid->oid_kind & CTLFLAG_VNET) &&
2373 		     prison_owns_vnet(req->td->td_ucred))
2374 			priv = PRIV_SYSCTL_WRITEJAIL;
2375 #endif
2376 		else
2377 			priv = PRIV_SYSCTL_WRITE;
2378 		error = priv_check(req->td, priv);
2379 		if (error)
2380 			goto out;
2381 	}
2382 
2383 	if (!oid->oid_handler) {
2384 		error = EINVAL;
2385 		goto out;
2386 	}
2387 
2388 	if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
2389 		arg1 = (int *)arg1 + indx;
2390 		arg2 -= indx;
2391 	} else {
2392 		arg1 = oid->oid_arg1;
2393 		arg2 = oid->oid_arg2;
2394 	}
2395 #ifdef MAC
2396 	error = mac_system_check_sysctl(req->td->td_ucred, oid, arg1, arg2,
2397 	    req);
2398 	if (error != 0)
2399 		goto out;
2400 #endif
2401 #ifdef VIMAGE
2402 	if ((oid->oid_kind & CTLFLAG_VNET) && arg1 != NULL)
2403 		arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
2404 #endif
2405 	error = sysctl_root_handler_locked(oid, arg1, arg2, req, &tracker);
2406 
2407 out:
2408 	SYSCTL_RUNLOCK(&tracker);
2409 	return (error);
2410 }
2411 
2412 #ifndef _SYS_SYSPROTO_H_
2413 struct __sysctl_args {
2414 	int	*name;
2415 	u_int	namelen;
2416 	void	*old;
2417 	size_t	*oldlenp;
2418 	void	*new;
2419 	size_t	newlen;
2420 };
2421 #endif
2422 int
2423 sys___sysctl(struct thread *td, struct __sysctl_args *uap)
2424 {
2425 	int error, i, name[CTL_MAXNAME];
2426 	size_t j;
2427 
2428 	if (uap->namelen > CTL_MAXNAME || uap->namelen < 2)
2429 		return (EINVAL);
2430 
2431  	error = copyin(uap->name, &name, uap->namelen * sizeof(int));
2432  	if (error)
2433 		return (error);
2434 
2435 	error = userland_sysctl(td, name, uap->namelen,
2436 		uap->old, uap->oldlenp, 0,
2437 		uap->new, uap->newlen, &j, 0);
2438 	if (error && error != ENOMEM)
2439 		return (error);
2440 	if (uap->oldlenp) {
2441 		i = copyout(&j, uap->oldlenp, sizeof(j));
2442 		if (i)
2443 			return (i);
2444 	}
2445 	return (error);
2446 }
2447 
2448 int
2449 kern___sysctlbyname(struct thread *td, const char *oname, size_t namelen,
2450     void *old, size_t *oldlenp, void *new, size_t newlen, size_t *retval,
2451     int flags, bool inkernel)
2452 {
2453 	int oid[CTL_MAXNAME];
2454 	char namebuf[16];
2455 	char *name;
2456 	size_t oidlen;
2457 	int error;
2458 
2459 	if (namelen > MAXPATHLEN || namelen == 0)
2460 		return (EINVAL);
2461 	name = namebuf;
2462 	if (namelen > sizeof(namebuf))
2463 		name = malloc(namelen, M_SYSCTL, M_WAITOK);
2464 	error = copyin(oname, name, namelen);
2465 	if (error != 0)
2466 		goto out;
2467 
2468 	oid[0] = CTL_SYSCTL;
2469 	oid[1] = CTL_SYSCTL_NAME2OID;
2470 	oidlen = sizeof(oid);
2471 	error = kernel_sysctl(td, oid, 2, oid, &oidlen, (void *)name, namelen,
2472 	    retval, flags);
2473 	if (error != 0)
2474 		goto out;
2475 	error = userland_sysctl(td, oid, *retval / sizeof(int), old, oldlenp,
2476 	    inkernel, new, newlen, retval, flags);
2477 
2478 out:
2479 	if (namelen > sizeof(namebuf))
2480 		free(name, M_SYSCTL);
2481 	return (error);
2482 }
2483 
2484 #ifndef	_SYS_SYSPROTO_H_
2485 struct __sysctlbyname_args {
2486 	const char	*name;
2487 	size_t	namelen;
2488 	void	*old;
2489 	size_t	*oldlenp;
2490 	void	*new;
2491 	size_t	newlen;
2492 };
2493 #endif
2494 int
2495 sys___sysctlbyname(struct thread *td, struct __sysctlbyname_args *uap)
2496 {
2497 	size_t rv;
2498 	int error;
2499 
2500 	error = kern___sysctlbyname(td, uap->name, uap->namelen, uap->old,
2501 	    uap->oldlenp, uap->new, uap->newlen, &rv, 0, 0);
2502 	if (error != 0)
2503 		return (error);
2504 	if (uap->oldlenp != NULL)
2505 		error = copyout(&rv, uap->oldlenp, sizeof(rv));
2506 
2507 	return (error);
2508 }
2509 
2510 /*
2511  * This is used from various compatibility syscalls too.  That's why name
2512  * must be in kernel space.
2513  */
2514 int
2515 userland_sysctl(struct thread *td, int *name, u_int namelen, void *old,
2516     size_t *oldlenp, int inkernel, const void *new, size_t newlen,
2517     size_t *retval, int flags)
2518 {
2519 	int error = 0, memlocked;
2520 	struct sysctl_req req;
2521 
2522 	bzero(&req, sizeof req);
2523 
2524 	req.td = td;
2525 	req.flags = flags;
2526 
2527 	if (oldlenp) {
2528 		if (inkernel) {
2529 			req.oldlen = *oldlenp;
2530 		} else {
2531 			error = copyin(oldlenp, &req.oldlen, sizeof(*oldlenp));
2532 			if (error)
2533 				return (error);
2534 		}
2535 	}
2536 	req.validlen = req.oldlen;
2537 	req.oldptr = old;
2538 
2539 	if (new != NULL) {
2540 		req.newlen = newlen;
2541 		req.newptr = new;
2542 	}
2543 
2544 	req.oldfunc = sysctl_old_user;
2545 	req.newfunc = sysctl_new_user;
2546 	req.lock = REQ_UNWIRED;
2547 
2548 #ifdef KTRACE
2549 	if (KTRPOINT(curthread, KTR_SYSCTL))
2550 		ktrsysctl(name, namelen);
2551 #endif
2552 	memlocked = 0;
2553 	if (req.oldptr && req.oldlen > 4 * PAGE_SIZE) {
2554 		memlocked = 1;
2555 		sx_xlock(&sysctlmemlock);
2556 	}
2557 	CURVNET_SET(TD_TO_VNET(td));
2558 
2559 	for (;;) {
2560 		req.oldidx = 0;
2561 		req.newidx = 0;
2562 		error = sysctl_root(0, name, namelen, &req);
2563 		if (error != EAGAIN)
2564 			break;
2565 		kern_yield(PRI_USER);
2566 	}
2567 
2568 	CURVNET_RESTORE();
2569 
2570 	if (req.lock == REQ_WIRED && req.validlen > 0)
2571 		vsunlock(req.oldptr, req.validlen);
2572 	if (memlocked)
2573 		sx_xunlock(&sysctlmemlock);
2574 
2575 	if (error && error != ENOMEM)
2576 		return (error);
2577 
2578 	if (retval) {
2579 		if (req.oldptr && req.oldidx > req.validlen)
2580 			*retval = req.validlen;
2581 		else
2582 			*retval = req.oldidx;
2583 	}
2584 	return (error);
2585 }
2586 
2587 /*
2588  * Drain into a sysctl struct.  The user buffer should be wired if a page
2589  * fault would cause issue.
2590  */
2591 static int
2592 sbuf_sysctl_drain(void *arg, const char *data, int len)
2593 {
2594 	struct sysctl_req *req = arg;
2595 	int error;
2596 
2597 	error = SYSCTL_OUT(req, data, len);
2598 	KASSERT(error >= 0, ("Got unexpected negative value %d", error));
2599 	return (error == 0 ? len : -error);
2600 }
2601 
2602 struct sbuf *
2603 sbuf_new_for_sysctl(struct sbuf *s, char *buf, int length,
2604     struct sysctl_req *req)
2605 {
2606 
2607 	/* Supply a default buffer size if none given. */
2608 	if (buf == NULL && length == 0)
2609 		length = 64;
2610 	s = sbuf_new(s, buf, length, SBUF_FIXEDLEN | SBUF_INCLUDENUL);
2611 	sbuf_set_drain(s, sbuf_sysctl_drain, req);
2612 	return (s);
2613 }
2614 
2615 #ifdef DDB
2616 
2617 /* The current OID the debugger is working with */
2618 static struct sysctl_oid *g_ddb_oid;
2619 
2620 /* The current flags specified by the user */
2621 static int g_ddb_sysctl_flags;
2622 
2623 /* Check to see if the last sysctl printed */
2624 static int g_ddb_sysctl_printed;
2625 
2626 static const int ctl_sign[CTLTYPE+1] = {
2627 	[CTLTYPE_INT] = 1,
2628 	[CTLTYPE_LONG] = 1,
2629 	[CTLTYPE_S8] = 1,
2630 	[CTLTYPE_S16] = 1,
2631 	[CTLTYPE_S32] = 1,
2632 	[CTLTYPE_S64] = 1,
2633 };
2634 
2635 static const int ctl_size[CTLTYPE+1] = {
2636 	[CTLTYPE_INT] = sizeof(int),
2637 	[CTLTYPE_UINT] = sizeof(u_int),
2638 	[CTLTYPE_LONG] = sizeof(long),
2639 	[CTLTYPE_ULONG] = sizeof(u_long),
2640 	[CTLTYPE_S8] = sizeof(int8_t),
2641 	[CTLTYPE_S16] = sizeof(int16_t),
2642 	[CTLTYPE_S32] = sizeof(int32_t),
2643 	[CTLTYPE_S64] = sizeof(int64_t),
2644 	[CTLTYPE_U8] = sizeof(uint8_t),
2645 	[CTLTYPE_U16] = sizeof(uint16_t),
2646 	[CTLTYPE_U32] = sizeof(uint32_t),
2647 	[CTLTYPE_U64] = sizeof(uint64_t),
2648 };
2649 
2650 #define DB_SYSCTL_NAME_ONLY	0x001	/* Compare with -N */
2651 #define DB_SYSCTL_VALUE_ONLY	0x002	/* Compare with -n */
2652 #define DB_SYSCTL_OPAQUE	0x004	/* Compare with -o */
2653 #define DB_SYSCTL_HEX		0x008	/* Compare with -x */
2654 
2655 #define DB_SYSCTL_SAFE_ONLY	0x100	/* Only simple types */
2656 
2657 static const char db_sysctl_modifs[] = {
2658 	'N', 'n', 'o', 'x',
2659 };
2660 
2661 static const int db_sysctl_modif_values[] = {
2662 	DB_SYSCTL_NAME_ONLY, DB_SYSCTL_VALUE_ONLY,
2663 	DB_SYSCTL_OPAQUE, DB_SYSCTL_HEX,
2664 };
2665 
2666 /* Handlers considered safe to print while recursing */
2667 static int (* const db_safe_handlers[])(SYSCTL_HANDLER_ARGS) = {
2668 	sysctl_handle_bool,
2669 	sysctl_handle_8,
2670 	sysctl_handle_16,
2671 	sysctl_handle_32,
2672 	sysctl_handle_64,
2673 	sysctl_handle_int,
2674 	sysctl_handle_long,
2675 	sysctl_handle_string,
2676 	sysctl_handle_opaque,
2677 };
2678 
2679 /*
2680  * Use in place of sysctl_old_kernel to print sysctl values.
2681  *
2682  * Compare to the output handling in show_var from sbin/sysctl/sysctl.c
2683  */
2684 static int
2685 sysctl_old_ddb(struct sysctl_req *req, const void *ptr, size_t len)
2686 {
2687 	const u_char *val, *p;
2688 	const char *sep1;
2689 	size_t intlen, slen;
2690 	uintmax_t umv;
2691 	intmax_t mv;
2692 	int sign, ctltype, hexlen, xflag, error;
2693 
2694 	/* Suppress false-positive GCC uninitialized variable warnings */
2695 	mv = 0;
2696 	umv = 0;
2697 
2698 	slen = len;
2699 	val = p = ptr;
2700 
2701 	if (ptr == NULL) {
2702 		error = 0;
2703 		goto out;
2704 	}
2705 
2706 	/* We are going to print */
2707 	g_ddb_sysctl_printed = 1;
2708 
2709 	xflag = g_ddb_sysctl_flags & DB_SYSCTL_HEX;
2710 
2711 	ctltype = (g_ddb_oid->oid_kind & CTLTYPE);
2712 	sign = ctl_sign[ctltype];
2713 	intlen = ctl_size[ctltype];
2714 
2715 	switch (ctltype) {
2716 	case CTLTYPE_NODE:
2717 	case CTLTYPE_STRING:
2718 		db_printf("%.*s", (int) len, (const char *) p);
2719 		error = 0;
2720 		goto out;
2721 
2722 	case CTLTYPE_INT:
2723 	case CTLTYPE_UINT:
2724 	case CTLTYPE_LONG:
2725 	case CTLTYPE_ULONG:
2726 	case CTLTYPE_S8:
2727 	case CTLTYPE_S16:
2728 	case CTLTYPE_S32:
2729 	case CTLTYPE_S64:
2730 	case CTLTYPE_U8:
2731 	case CTLTYPE_U16:
2732 	case CTLTYPE_U32:
2733 	case CTLTYPE_U64:
2734 		hexlen = 2 + (intlen * CHAR_BIT + 3) / 4;
2735 		sep1 = "";
2736 		while (len >= intlen) {
2737 			switch (ctltype) {
2738 			case CTLTYPE_INT:
2739 			case CTLTYPE_UINT:
2740 				umv = *(const u_int *)p;
2741 				mv = *(const int *)p;
2742 				break;
2743 			case CTLTYPE_LONG:
2744 			case CTLTYPE_ULONG:
2745 				umv = *(const u_long *)p;
2746 				mv = *(const long *)p;
2747 				break;
2748 			case CTLTYPE_S8:
2749 			case CTLTYPE_U8:
2750 				umv = *(const uint8_t *)p;
2751 				mv = *(const int8_t *)p;
2752 				break;
2753 			case CTLTYPE_S16:
2754 			case CTLTYPE_U16:
2755 				umv = *(const uint16_t *)p;
2756 				mv = *(const int16_t *)p;
2757 				break;
2758 			case CTLTYPE_S32:
2759 			case CTLTYPE_U32:
2760 				umv = *(const uint32_t *)p;
2761 				mv = *(const int32_t *)p;
2762 				break;
2763 			case CTLTYPE_S64:
2764 			case CTLTYPE_U64:
2765 				umv = *(const uint64_t *)p;
2766 				mv = *(const int64_t *)p;
2767 				break;
2768 			}
2769 
2770 			db_printf("%s", sep1);
2771 			if (xflag)
2772 				db_printf("%#0*jx", hexlen, umv);
2773 			else if (!sign)
2774 				db_printf("%ju", umv);
2775 			else if (g_ddb_oid->oid_fmt[1] == 'K') {
2776 				/* Kelvins are currently unsupported. */
2777 				error = EOPNOTSUPP;
2778 				goto out;
2779 			} else
2780 				db_printf("%jd", mv);
2781 
2782 			sep1 = " ";
2783 			len -= intlen;
2784 			p += intlen;
2785 		}
2786 		error = 0;
2787 		goto out;
2788 
2789 	case CTLTYPE_OPAQUE:
2790 		/* TODO: Support struct functions. */
2791 
2792 		/* FALLTHROUGH */
2793 	default:
2794 		db_printf("Format:%s Length:%zu Dump:0x",
2795 		    g_ddb_oid->oid_fmt, len);
2796 		while (len-- && (xflag || p < val + 16))
2797 			db_printf("%02x", *p++);
2798 		if (!xflag && len > 16)
2799 			db_printf("...");
2800 		error = 0;
2801 		goto out;
2802 	}
2803 
2804 out:
2805 	req->oldidx += slen;
2806 	return (error);
2807 }
2808 
2809 /*
2810  * Avoid setting new sysctl values from the debugger
2811  */
2812 static int
2813 sysctl_new_ddb(struct sysctl_req *req, void *p, size_t l)
2814 {
2815 
2816 	if (!req->newptr)
2817 		return (0);
2818 
2819 	/* Changing sysctls from the debugger is currently unsupported */
2820 	return (EPERM);
2821 }
2822 
2823 /*
2824  * Run a sysctl handler with the DDB oldfunc and newfunc attached.
2825  * Instead of copying any output to a buffer we'll dump it right to
2826  * the console.
2827  */
2828 static int
2829 db_sysctl(struct sysctl_oid *oidp, int *name, u_int namelen,
2830     void *old, size_t *oldlenp, size_t *retval, int flags)
2831 {
2832 	struct sysctl_req req;
2833 	int error;
2834 
2835 	/* Setup the request */
2836 	bzero(&req, sizeof req);
2837 	req.td = kdb_thread;
2838 	req.oldfunc = sysctl_old_ddb;
2839 	req.newfunc = sysctl_new_ddb;
2840 	req.lock = REQ_UNWIRED;
2841 	if (oldlenp) {
2842 		req.oldlen = *oldlenp;
2843 	}
2844 	req.validlen = req.oldlen;
2845 	if (old) {
2846 		req.oldptr = old;
2847 	}
2848 
2849 	/* Setup our globals for sysctl_old_ddb */
2850 	g_ddb_oid = oidp;
2851 	g_ddb_sysctl_flags = flags;
2852 	g_ddb_sysctl_printed = 0;
2853 
2854 	error = sysctl_root(0, name, namelen, &req);
2855 
2856 	/* Reset globals */
2857 	g_ddb_oid = NULL;
2858 	g_ddb_sysctl_flags = 0;
2859 
2860 	if (retval) {
2861 		if (req.oldptr && req.oldidx > req.validlen)
2862 			*retval = req.validlen;
2863 		else
2864 			*retval = req.oldidx;
2865 	}
2866 	return (error);
2867 }
2868 
2869 /*
2870  * Show a sysctl's name
2871  */
2872 static void
2873 db_show_oid_name(int *oid, size_t nlen)
2874 {
2875 	struct sysctl_oid *oidp;
2876 	int qoid[CTL_MAXNAME + 2];
2877 	int error;
2878 
2879 	qoid[0] = CTL_SYSCTL;
2880 	qoid[1] = CTL_SYSCTL_NAME;
2881 	memcpy(qoid + 2, oid, nlen * sizeof(int));
2882 
2883 	error = sysctl_find_oid(qoid, nlen + 2, &oidp, NULL, NULL);
2884 	if (error)
2885 		db_error("sysctl name oid");
2886 
2887 	error = db_sysctl(oidp, qoid, nlen + 2, NULL, NULL, NULL, 0);
2888 	if (error)
2889 		db_error("sysctl name");
2890 }
2891 
2892 /*
2893  * Check to see if an OID is safe to print from ddb.
2894  */
2895 static bool
2896 db_oid_safe(const struct sysctl_oid *oidp)
2897 {
2898 	for (unsigned int i = 0; i < nitems(db_safe_handlers); ++i) {
2899 		if (oidp->oid_handler == db_safe_handlers[i])
2900 			return (true);
2901 	}
2902 
2903 	return (false);
2904 }
2905 
2906 /*
2907  * Show a sysctl at a specific OID
2908  * Compare to the input handling in show_var from sbin/sysctl/sysctl.c
2909  */
2910 static int
2911 db_show_oid(struct sysctl_oid *oidp, int *oid, size_t nlen, int flags)
2912 {
2913 	int error, xflag, oflag, Nflag, nflag;
2914 	size_t len;
2915 
2916 	xflag = flags & DB_SYSCTL_HEX;
2917 	oflag = flags & DB_SYSCTL_OPAQUE;
2918 	nflag = flags & DB_SYSCTL_VALUE_ONLY;
2919 	Nflag = flags & DB_SYSCTL_NAME_ONLY;
2920 
2921 	if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_OPAQUE &&
2922 	    (!xflag && !oflag))
2923 		return (0);
2924 
2925 	if (Nflag) {
2926 		db_show_oid_name(oid, nlen);
2927 		error = 0;
2928 		goto out;
2929 	}
2930 
2931 	if (!nflag) {
2932 		db_show_oid_name(oid, nlen);
2933 		db_printf(": ");
2934 	}
2935 
2936 	if ((flags & DB_SYSCTL_SAFE_ONLY) && !db_oid_safe(oidp)) {
2937 		db_printf("Skipping, unsafe to print while recursing.");
2938 		error = 0;
2939 		goto out;
2940 	}
2941 
2942 	/* Try once, and ask about the size */
2943 	len = 0;
2944 	error = db_sysctl(oidp, oid, nlen,
2945 	    NULL, NULL, &len, flags);
2946 	if (error)
2947 		goto out;
2948 
2949 	if (!g_ddb_sysctl_printed)
2950 		/* Lie about the size */
2951 		error = db_sysctl(oidp, oid, nlen,
2952 		    (void *) 1, &len, NULL, flags);
2953 
2954 out:
2955 	db_printf("\n");
2956 	return (error);
2957 }
2958 
2959 /*
2960  * Show all sysctls under a specific OID
2961  * Compare to sysctl_all from sbin/sysctl/sysctl.c
2962  */
2963 static int
2964 db_show_sysctl_all(int *oid, size_t len, int flags)
2965 {
2966 	struct sysctl_oid *oidp;
2967 	int qoid[CTL_MAXNAME + 2], next[CTL_MAXNAME];
2968 	size_t nlen;
2969 
2970 	qoid[0] = CTL_SYSCTL;
2971 	qoid[1] = CTL_SYSCTL_NEXT;
2972 	if (len) {
2973 		nlen = len;
2974 		memcpy(&qoid[2], oid, nlen * sizeof(int));
2975 	} else {
2976 		nlen = 1;
2977 		qoid[2] = CTL_KERN;
2978 	}
2979 	for (;;) {
2980 		int error;
2981 		size_t nextsize = sizeof(next);
2982 
2983 		error = kernel_sysctl(kdb_thread, qoid, nlen + 2,
2984 		    next, &nextsize, NULL, 0, &nlen, 0);
2985 		if (error != 0) {
2986 			if (error == ENOENT)
2987 				return (0);
2988 			else
2989 				db_error("sysctl(next)");
2990 		}
2991 
2992 		nlen /= sizeof(int);
2993 
2994 		if (nlen < (unsigned int)len)
2995 			return (0);
2996 
2997 		if (memcmp(&oid[0], &next[0], len * sizeof(int)) != 0)
2998 			return (0);
2999 
3000 		/* Find the OID in question */
3001 		error = sysctl_find_oid(next, nlen, &oidp, NULL, NULL);
3002 		if (error)
3003 			return (error);
3004 
3005 		(void)db_show_oid(oidp, next, nlen, flags | DB_SYSCTL_SAFE_ONLY);
3006 
3007 		if (db_pager_quit)
3008 			return (0);
3009 
3010 		memcpy(&qoid[2 + len], &next[len], (nlen - len) * sizeof(int));
3011 	}
3012 }
3013 
3014 /*
3015  * Show a sysctl by its user facing string
3016  */
3017 static int
3018 db_sysctlbyname(const char *name, int flags)
3019 {
3020 	struct sysctl_oid *oidp;
3021 	int oid[CTL_MAXNAME];
3022 	int error, nlen;
3023 
3024 	error = name2oid(name, oid, &nlen, &oidp);
3025 	if (error) {
3026 		return (error);
3027 	}
3028 
3029 	if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
3030 		db_show_sysctl_all(oid, nlen, flags);
3031 	} else {
3032 		error = db_show_oid(oidp, oid, nlen, flags);
3033 	}
3034 
3035 	return (error);
3036 }
3037 
3038 static void
3039 db_sysctl_cmd_usage(void)
3040 {
3041 	db_printf(
3042 	    " sysctl [/Nnox] <sysctl>					    \n"
3043 	    "								    \n"
3044 	    " <sysctl> The name of the sysctl to show.			    \n"
3045 	    "								    \n"
3046 	    " Show a sysctl by hooking into SYSCTL_IN and SYSCTL_OUT.	    \n"
3047 	    " This will work for most sysctls, but should not be used	    \n"
3048 	    " with sysctls that are known to malloc.			    \n"
3049 	    "								    \n"
3050 	    " While recursing any \"unsafe\" sysctls will be skipped.	    \n"
3051 	    " Call sysctl directly on the sysctl to try printing the	    \n"
3052 	    " skipped sysctl. This is unsafe and may make the ddb	    \n"
3053 	    " session unusable.						    \n"
3054 	    "								    \n"
3055 	    " Arguments:						    \n"
3056 	    "	/N	Display only the name of the sysctl.		    \n"
3057 	    "	/n	Display only the value of the sysctl.		    \n"
3058 	    "	/o	Display opaque values.				    \n"
3059 	    "	/x	Display the sysctl in hex.			    \n"
3060 	    "								    \n"
3061 	    "For example:						    \n"
3062 	    "sysctl vm.v_free_min					    \n"
3063 	    "vn.v_free_min: 12669					    \n"
3064 	    );
3065 }
3066 
3067 /*
3068  * Show a specific sysctl similar to sysctl (8).
3069  */
3070 DB_COMMAND_FLAGS(sysctl, db_sysctl_cmd, CS_OWN)
3071 {
3072 	char name[TOK_STRING_SIZE];
3073 	int error, i, t, flags;
3074 
3075 	/* Parse the modifiers */
3076 	t = db_read_token();
3077 	if (t == tSLASH || t == tMINUS) {
3078 		t = db_read_token();
3079 		if (t != tIDENT) {
3080 			db_printf("Bad modifier\n");
3081 			error = EINVAL;
3082 			goto out;
3083 		}
3084 		db_strcpy(modif, db_tok_string);
3085 	}
3086 	else {
3087 		db_unread_token(t);
3088 		modif[0] = '\0';
3089 	}
3090 
3091 	flags = 0;
3092 	for (i = 0; i < nitems(db_sysctl_modifs); i++) {
3093 		if (strchr(modif, db_sysctl_modifs[i])) {
3094 			flags |= db_sysctl_modif_values[i];
3095 		}
3096 	}
3097 
3098 	/* Parse the sysctl names */
3099 	t = db_read_token();
3100 	if (t != tIDENT) {
3101 		db_printf("Need sysctl name\n");
3102 		error = EINVAL;
3103 		goto out;
3104 	}
3105 
3106 	/* Copy the name into a temporary buffer */
3107 	db_strcpy(name, db_tok_string);
3108 
3109 	/* Ensure there is no trailing cruft */
3110 	t = db_read_token();
3111 	if (t != tEOL) {
3112 		db_printf("Unexpected sysctl argument\n");
3113 		error = EINVAL;
3114 		goto out;
3115 	}
3116 
3117 	error = db_sysctlbyname(name, flags);
3118 	if (error == ENOENT) {
3119 		db_printf("unknown oid: '%s'\n", db_tok_string);
3120 		goto out;
3121 	} else if (error) {
3122 		db_printf("%s: error: %d\n", db_tok_string, error);
3123 		goto out;
3124 	}
3125 
3126 out:
3127 	/* Ensure we eat all of our text */
3128 	db_flush_lex();
3129 
3130 	if (error == EINVAL) {
3131 		db_sysctl_cmd_usage();
3132 	}
3133 }
3134 
3135 #endif /* DDB */
3136