xref: /freebsd/sys/kern/kern_mib.c (revision e9ac41698b2f322d55ccf9da50a3596edb2c1800)
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_posix.h"
40 #include "opt_config.h"
41 
42 #include <sys/param.h>
43 #include <sys/boot.h>
44 #include <sys/elf.h>
45 #include <sys/jail.h>
46 #include <sys/kernel.h>
47 #include <sys/limits.h>
48 #include <sys/lock.h>
49 #include <sys/mutex.h>
50 #include <sys/proc.h>
51 #include <sys/random.h>
52 #include <sys/sbuf.h>
53 #include <sys/smp.h>
54 #include <sys/sx.h>
55 #include <sys/sysent.h>
56 #include <sys/vmmeter.h>
57 #include <sys/sysctl.h>
58 #include <sys/systm.h>
59 #include <sys/unistd.h>
60 
61 #include <vm/vm_param.h>
62 
63 SYSCTL_ROOT_NODE(0, sysctl, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
64     "Sysctl internal magic");
65 SYSCTL_ROOT_NODE(CTL_KERN, kern, CTLFLAG_RW | CTLFLAG_CAPRD | CTLFLAG_MPSAFE, 0,
66     "High kernel, proc, limits &c");
67 SYSCTL_ROOT_NODE(CTL_VM, vm, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
68     "Virtual memory");
69 SYSCTL_ROOT_NODE(CTL_VFS, vfs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
70     "File system");
71 SYSCTL_ROOT_NODE(CTL_NET, net, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
72     "Network, (see socket.h)");
73 SYSCTL_ROOT_NODE(CTL_DEBUG, debug, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
74     "Debugging");
75 SYSCTL_NODE(_debug, OID_AUTO,  sizeof,  CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
76     "Sizeof various things");
77 SYSCTL_ROOT_NODE(CTL_HW, hw, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
78     "hardware");
79 SYSCTL_ROOT_NODE(CTL_MACHDEP, machdep, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
80     "machine dependent");
81 SYSCTL_NODE(_machdep, OID_AUTO, mitigations, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
82     "Machine dependent platform mitigations.");
83 SYSCTL_ROOT_NODE(CTL_USER, user, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
84     "user-level");
85 SYSCTL_ROOT_NODE(CTL_P1003_1B, p1003_1b, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
86     "p1003_1b, (see p1003_1b.h)");
87 
88 SYSCTL_ROOT_NODE(OID_AUTO, compat, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
89     "Compatibility code");
90 SYSCTL_ROOT_NODE(OID_AUTO, security, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
91     "Security");
92 #ifdef REGRESSION
93 SYSCTL_ROOT_NODE(OID_AUTO, regression, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
94     "Regression test MIB");
95 #endif
96 
97 SYSCTL_STRING(_kern, OID_AUTO, ident, CTLFLAG_RD,
98     kern_ident, 0, "Kernel identifier");
99 
100 SYSCTL_INT(_kern, KERN_OSREV, osrevision, CTLFLAG_RD | CTLFLAG_CAPRD,
101     SYSCTL_NULL_INT_PTR, BSD, "Operating system revision");
102 
103 SYSCTL_STRING(_kern, KERN_VERSION, version, CTLFLAG_RD,
104     version, 0, "Kernel version");
105 
106 SYSCTL_STRING(_kern, OID_AUTO, compiler_version, CTLFLAG_RD,
107     compiler_version, 0, "Version of compiler used to compile kernel");
108 
109 SYSCTL_STRING(_kern, KERN_OSTYPE, ostype, CTLFLAG_RD | CTLFLAG_CAPRD,
110     ostype, 0, "Operating system type");
111 
112 SYSCTL_INT(_kern, KERN_MAXPROC, maxproc, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
113     &maxproc, 0, "Maximum number of processes");
114 
115 SYSCTL_INT(_kern, KERN_MAXPROCPERUID, maxprocperuid, CTLFLAG_RW,
116     &maxprocperuid, 0, "Maximum processes allowed per userid");
117 
118 SYSCTL_INT(_kern, OID_AUTO, maxusers, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
119     &maxusers, 0, "Hint for kernel tuning");
120 
121 SYSCTL_INT(_kern, KERN_ARGMAX, argmax, CTLFLAG_RD|CTLFLAG_CAPRD,
122     SYSCTL_NULL_INT_PTR, ARG_MAX, "Maximum bytes of argument to execve(2)");
123 
124 SYSCTL_INT(_kern, KERN_POSIX1, posix1version, CTLFLAG_RD|CTLFLAG_CAPRD,
125     SYSCTL_NULL_INT_PTR, _POSIX_VERSION, "Version of POSIX attempting to comply to");
126 
127 SYSCTL_INT(_kern, KERN_NGROUPS, ngroups, CTLFLAG_RDTUN |
128     CTLFLAG_NOFETCH | CTLFLAG_CAPRD, &ngroups_max, 0,
129     "Maximum number of supplemental groups a user can belong to");
130 
131 SYSCTL_INT(_kern, KERN_JOB_CONTROL, job_control, CTLFLAG_RD|CTLFLAG_CAPRD,
132     SYSCTL_NULL_INT_PTR, 1, "Whether job control is available");
133 
134 #ifdef _POSIX_SAVED_IDS
135 SYSCTL_INT(_kern, KERN_SAVED_IDS, saved_ids, CTLFLAG_RD|CTLFLAG_CAPRD,
136     SYSCTL_NULL_INT_PTR, 1, "Whether saved set-group/user ID is available");
137 #else
138 SYSCTL_INT(_kern, KERN_SAVED_IDS, saved_ids, CTLFLAG_RD|CTLFLAG_CAPRD,
139     SYSCTL_NULL_INT_PTR, 0, "Whether saved set-group/user ID is available");
140 #endif
141 
142 char kernelname[MAXPATHLEN] = PATH_KERNEL;	/* XXX bloat */
143 
144 SYSCTL_STRING(_kern, KERN_BOOTFILE, bootfile, CTLFLAG_RW,
145     kernelname, sizeof kernelname, "Name of kernel file booted");
146 
147 #ifdef COMPAT_FREEBSD12
148 static int
149 sysctl_maxphys(SYSCTL_HANDLER_ARGS)
150 {
151 	u_long lvalue;
152 	int ivalue;
153 
154 	lvalue = maxphys;
155 	if (sizeof(int) == sizeof(u_long) || req->oldlen >= sizeof(u_long))
156 		return (sysctl_handle_long(oidp, &lvalue, 0, req));
157 	if (lvalue > INT_MAX)
158 		return (sysctl_handle_long(oidp, &lvalue, 0, req));
159 	ivalue = lvalue;
160 	return (sysctl_handle_int(oidp, &ivalue, 0, req));
161 }
162 SYSCTL_PROC(_kern, KERN_MAXPHYS, maxphys, CTLTYPE_LONG | CTLFLAG_RDTUN |
163     CTLFLAG_NOFETCH | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
164     NULL, 0, sysctl_maxphys, "UL", "Maximum block I/O access size");
165 #else
166 SYSCTL_ULONG(_kern, KERN_MAXPHYS, maxphys,
167     CTLFLAG_RDTUN | CTLFLAG_NOFETCH | CTLFLAG_CAPRD,
168     &maxphys, 0, "Maximum block I/O access size");
169 #endif
170 
171 SYSCTL_INT(_hw, HW_NCPU, ncpu, CTLFLAG_RD|CTLFLAG_CAPRD,
172     &mp_ncpus, 0, "Number of active CPUs");
173 
174 SYSCTL_INT(_hw, HW_BYTEORDER, byteorder, CTLFLAG_RD|CTLFLAG_CAPRD,
175     SYSCTL_NULL_INT_PTR, BYTE_ORDER, "System byte order");
176 
177 SYSCTL_INT(_hw, HW_PAGESIZE, pagesize, CTLFLAG_RD|CTLFLAG_CAPRD,
178     SYSCTL_NULL_INT_PTR, PAGE_SIZE, "System memory page size");
179 
180 static int
181 sysctl_kern_arnd(SYSCTL_HANDLER_ARGS)
182 {
183 	char buf[256];
184 	size_t len;
185 	int error;
186 
187 	len = MIN(req->oldlen, sizeof(buf));
188 	read_random(buf, len);
189 
190 	error = SYSCTL_OUT(req, buf, len);
191 	explicit_bzero(buf, len);
192 	return (error);
193 }
194 
195 SYSCTL_PROC(_kern, KERN_ARND, arandom,
196     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD, NULL, 0,
197     sysctl_kern_arnd, "", "arc4rand");
198 
199 static int
200 sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
201 {
202 	u_long val, p;
203 
204 	p = SIZE_T_MAX >> PAGE_SHIFT;
205 	if (physmem < p)
206 		p = physmem;
207 	val = ctob(p);
208 	return (sysctl_handle_long(oidp, &val, 0, req));
209 }
210 SYSCTL_PROC(_hw, HW_PHYSMEM, physmem,
211     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
212     sysctl_hw_physmem, "LU",
213     "Amount of physical memory (in bytes)");
214 
215 static int
216 sysctl_hw_realmem(SYSCTL_HANDLER_ARGS)
217 {
218 	u_long val, p;
219 
220 	p = SIZE_T_MAX >> PAGE_SHIFT;
221 	if (realmem < p)
222 		p = realmem;
223 	val = ctob(p);
224 	return (sysctl_handle_long(oidp, &val, 0, req));
225 }
226 SYSCTL_PROC(_hw, HW_REALMEM, realmem,
227     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
228     sysctl_hw_realmem, "LU",
229     "Amount of memory (in bytes) reported by the firmware");
230 
231 static int
232 sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
233 {
234 	u_long val, p, p1;
235 
236 	p1 = physmem - vm_wire_count();
237 	p = SIZE_T_MAX >> PAGE_SHIFT;
238 	if (p1 < p)
239 		p = p1;
240 	val = ctob(p);
241 	return (sysctl_handle_long(oidp, &val, 0, req));
242 }
243 SYSCTL_PROC(_hw, HW_USERMEM, usermem,
244     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
245     sysctl_hw_usermem, "LU",
246     "Amount of memory (in bytes) which is not wired");
247 
248 SYSCTL_LONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &physmem, 0,
249     "Amount of physical memory (in pages)");
250 
251 #if VM_NRESERVLEVEL > 0
252 _Static_assert(MAXPAGESIZES > VM_NRESERVLEVEL, "MAXPAGESIZES is too small");
253 #endif
254 
255 u_long __read_mostly pagesizes[MAXPAGESIZES] = { PAGE_SIZE };
256 
257 static int
258 sysctl_hw_pagesizes(SYSCTL_HANDLER_ARGS)
259 {
260 	int error;
261 	size_t len;
262 #ifdef SCTL_MASK32
263 	int i;
264 	uint32_t pagesizes32[MAXPAGESIZES];
265 
266 	if (req->flags & SCTL_MASK32) {
267 		/*
268 		 * Recreate the "pagesizes" array with 32-bit elements.
269 		 * Truncate any page size greater than UINT32_MAX to zero,
270 		 * which assumes that page sizes are powers of two.
271 		 */
272 		for (i = 0; i < MAXPAGESIZES; i++)
273 			pagesizes32[i] = (uint32_t)pagesizes[i];
274 
275 		len = sizeof(pagesizes32);
276 		if (len > req->oldlen && req->oldptr != NULL)
277 			len = req->oldlen;
278 		error = SYSCTL_OUT(req, pagesizes32, len);
279 	} else
280 #endif
281 	{
282 		len = sizeof(pagesizes);
283 		if (len > req->oldlen && req->oldptr != NULL)
284 			len = req->oldlen;
285 		error = SYSCTL_OUT(req, pagesizes, len);
286 	}
287 	return (error);
288 }
289 SYSCTL_PROC(_hw, OID_AUTO, pagesizes,
290     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
291     sysctl_hw_pagesizes, "S,pagesizes",
292     "Supported page sizes");
293 
294 int adaptive_machine_arch = 1;
295 SYSCTL_INT(_debug, OID_AUTO, adaptive_machine_arch, CTLFLAG_RW,
296     &adaptive_machine_arch, 1,
297     "Adapt reported machine architecture to the ABI of the binary");
298 
299 static const char *
300 proc_machine_arch(struct proc *p)
301 {
302 
303 	if (p->p_sysent->sv_machine_arch != NULL)
304 		return (p->p_sysent->sv_machine_arch(p));
305 #ifdef COMPAT_FREEBSD32
306 	if (SV_PROC_FLAG(p, SV_ILP32))
307 		return (MACHINE_ARCH32);
308 #endif
309 	return (MACHINE_ARCH);
310 }
311 
312 static int
313 sysctl_hw_machine_arch(SYSCTL_HANDLER_ARGS)
314 {
315 	const char *machine_arch;
316 
317 	if (adaptive_machine_arch)
318 		machine_arch = proc_machine_arch(curproc);
319 	else
320 		machine_arch = MACHINE_ARCH;
321 	return (SYSCTL_OUT(req, machine_arch, strlen(machine_arch) + 1));
322 }
323 SYSCTL_PROC(_hw, HW_MACHINE_ARCH, machine_arch, CTLTYPE_STRING | CTLFLAG_RD |
324     CTLFLAG_CAPRD | CTLFLAG_MPSAFE, NULL, 0, sysctl_hw_machine_arch, "A",
325     "System architecture");
326 
327 #ifdef COMPAT_FREEBSD32
328 #include <compat/freebsd32/freebsd32_util.h>
329 #endif
330 
331 static int
332 sysctl_kern_supported_archs(SYSCTL_HANDLER_ARGS)
333 {
334 	const char *supported_archs;
335 
336 	supported_archs =
337 #ifdef COMPAT_FREEBSD32
338 	    compat_freebsd_32bit ? MACHINE_ARCH " " MACHINE_ARCH32 :
339 #endif
340 	    MACHINE_ARCH;
341 	return (SYSCTL_OUT(req, supported_archs, strlen(supported_archs) + 1));
342 }
343 SYSCTL_PROC(_kern, OID_AUTO, supported_archs, CTLFLAG_RD | CTLFLAG_MPSAFE |
344     CTLFLAG_CAPRD | CTLTYPE_STRING, NULL, 0, sysctl_kern_supported_archs, "A",
345     "Supported architectures for binaries");
346 
347 static int
348 sysctl_hostname(SYSCTL_HANDLER_ARGS)
349 {
350 	struct prison *pr, *cpr;
351 	size_t pr_offset;
352 	char tmpname[MAXHOSTNAMELEN];
353 	int descend, error, len;
354 
355 	/*
356 	 * This function can set: hostname domainname hostuuid.
357 	 * Keep that in mind when comments say "hostname".
358 	 */
359 	pr_offset = (size_t)arg1;
360 	len = arg2;
361 	KASSERT(len <= sizeof(tmpname),
362 	    ("length %d too long for %s", len, __func__));
363 
364 	/*
365 	 * Make a local copy of hostname to get/set so we don't have to hold
366 	 * the jail mutex during the sysctl copyin/copyout activities.
367 	 */
368 	pr = req->td->td_ucred->cr_prison;
369 	mtx_lock(&pr->pr_mtx);
370 	bcopy((char *)pr + pr_offset, tmpname, len);
371 	mtx_unlock(&pr->pr_mtx);
372 
373 	error = sysctl_handle_string(oidp, tmpname, len, req);
374 	if (error != 0 || req->newptr == NULL)
375 		return (error);
376 
377 	/*
378 	 * Copy the locally set hostname to all jails that share
379 	 * this host info.
380 	 */
381 	sx_slock(&allprison_lock);
382 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME))
383 		error = EPERM;
384 	else {
385 		while (!(pr->pr_flags & PR_HOST))
386 			pr = pr->pr_parent;
387 		mtx_lock(&pr->pr_mtx);
388 		bcopy(tmpname, (char *)pr + pr_offset, len);
389 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
390 			if (cpr->pr_flags & PR_HOST)
391 				descend = 0;
392 			else
393 				bcopy(tmpname, (char *)cpr + pr_offset, len);
394 		mtx_unlock(&pr->pr_mtx);
395 	}
396 	sx_sunlock(&allprison_lock);
397 	return (error);
398 }
399 
400 SYSCTL_PROC(_kern, KERN_HOSTNAME, hostname,
401     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
402     (void *)(offsetof(struct prison, pr_hostname)), MAXHOSTNAMELEN,
403     sysctl_hostname, "A", "Hostname");
404 SYSCTL_PROC(_kern, KERN_NISDOMAINNAME, domainname,
405     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
406     (void *)(offsetof(struct prison, pr_domainname)), MAXHOSTNAMELEN,
407     sysctl_hostname, "A", "Name of the current YP/NIS domain");
408 SYSCTL_PROC(_kern, KERN_HOSTUUID, hostuuid,
409     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
410     (void *)(offsetof(struct prison, pr_hostuuid)), HOSTUUIDLEN,
411     sysctl_hostname, "A", "Host UUID");
412 
413 static int	regression_securelevel_nonmonotonic = 0;
414 
415 #ifdef REGRESSION
416 SYSCTL_INT(_regression, OID_AUTO, securelevel_nonmonotonic, CTLFLAG_RW,
417     &regression_securelevel_nonmonotonic, 0, "securelevel may be lowered");
418 #endif
419 
420 static int
421 sysctl_kern_securelvl(SYSCTL_HANDLER_ARGS)
422 {
423 	struct prison *pr, *cpr;
424 	int descend, error, level;
425 
426 	pr = req->td->td_ucred->cr_prison;
427 
428 	/*
429 	 * Reading the securelevel is easy, since the current jail's level
430 	 * is known to be at least as secure as any higher levels.  Perform
431 	 * a lockless read since the securelevel is an integer.
432 	 */
433 	level = pr->pr_securelevel;
434 	error = sysctl_handle_int(oidp, &level, 0, req);
435 	if (error || !req->newptr)
436 		return (error);
437 	/* Permit update only if the new securelevel exceeds the old. */
438 	sx_slock(&allprison_lock);
439 	mtx_lock(&pr->pr_mtx);
440 	if (!regression_securelevel_nonmonotonic &&
441 	    level < pr->pr_securelevel) {
442 		mtx_unlock(&pr->pr_mtx);
443 		sx_sunlock(&allprison_lock);
444 		return (EPERM);
445 	}
446 	pr->pr_securelevel = level;
447 	/*
448 	 * Set all child jails to be at least this level, but do not lower
449 	 * them (even if regression_securelevel_nonmonotonic).
450 	 */
451 	FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend) {
452 		if (cpr->pr_securelevel < level)
453 			cpr->pr_securelevel = level;
454 	}
455 	mtx_unlock(&pr->pr_mtx);
456 	sx_sunlock(&allprison_lock);
457 	return (error);
458 }
459 
460 SYSCTL_PROC(_kern, KERN_SECURELVL, securelevel,
461     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE, 0, 0,
462     sysctl_kern_securelvl, "I",
463     "Current secure level");
464 
465 #ifdef INCLUDE_CONFIG_FILE
466 /* Actual kernel configuration options. */
467 extern char kernconfstring[];
468 
469 SYSCTL_STRING(_kern, OID_AUTO, conftxt, CTLFLAG_RD,
470     kernconfstring, 0, "Kernel configuration file");
471 #endif
472 
473 static int
474 sysctl_hostid(SYSCTL_HANDLER_ARGS)
475 {
476 	struct prison *pr, *cpr;
477 	u_long tmpid;
478 	int descend, error;
479 
480 	/*
481 	 * Like sysctl_hostname, except it operates on a u_long
482 	 * instead of a string, and is used only for hostid.
483 	 */
484 	pr = req->td->td_ucred->cr_prison;
485 	mtx_lock(&pr->pr_mtx);
486 	tmpid = pr->pr_hostid;
487 	mtx_unlock(&pr->pr_mtx);
488 
489 	error = sysctl_handle_long(oidp, &tmpid, 0, req);
490 	if (error != 0 || req->newptr == NULL)
491 		return (error);
492 
493 	sx_slock(&allprison_lock);
494 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME))
495 		error = EPERM;
496 	else {
497 		while (!(pr->pr_flags & PR_HOST))
498 			pr = pr->pr_parent;
499 		mtx_lock(&pr->pr_mtx);
500 		pr->pr_hostid = tmpid;
501 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
502 			if (cpr->pr_flags & PR_HOST)
503 				descend = 0;
504 			else
505 				cpr->pr_hostid = tmpid;
506 		mtx_unlock(&pr->pr_mtx);
507 	}
508 	sx_sunlock(&allprison_lock);
509 	return (error);
510 }
511 
512 SYSCTL_PROC(_kern, KERN_HOSTID, hostid,
513     CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
514     NULL, 0, sysctl_hostid, "LU", "Host ID");
515 
516 static struct mtx bootid_lk;
517 MTX_SYSINIT(bootid_lock, &bootid_lk, "bootid generator lock", MTX_DEF);
518 
519 static int
520 sysctl_bootid(SYSCTL_HANDLER_ARGS)
521 {
522 	static uint8_t boot_id[16];
523 	static bool initialized = false;
524 
525 	mtx_lock(&bootid_lk);
526 	if (!initialized) {
527 		if (!is_random_seeded()) {
528 			mtx_unlock(&bootid_lk);
529 			return (ENXIO);
530 		}
531 		arc4random_buf(boot_id, sizeof(boot_id));
532 		initialized = true;
533 	}
534 	mtx_unlock(&bootid_lk);
535 
536 	return (SYSCTL_OUT(req, boot_id, sizeof(boot_id)));
537 }
538 SYSCTL_PROC(_kern, OID_AUTO, boot_id,
539     CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
540     NULL, 0, sysctl_bootid, "", "Random boot ID");
541 
542 /*
543  * The osrelease string is copied from the global (osrelease in vers.c) into
544  * prison0 by a sysinit and is inherited by child jails if not changed at jail
545  * creation, so we always return the copy from the current prison data.
546  */
547 static int
548 sysctl_osrelease(SYSCTL_HANDLER_ARGS)
549 {
550 	struct prison *pr;
551 
552 	pr = req->td->td_ucred->cr_prison;
553 	return (SYSCTL_OUT(req, pr->pr_osrelease, strlen(pr->pr_osrelease) + 1));
554 
555 }
556 
557 SYSCTL_PROC(_kern, KERN_OSRELEASE, osrelease,
558     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
559     NULL, 0, sysctl_osrelease, "A", "Operating system release");
560 
561 /*
562  * The osreldate number is copied from the global (osreldate in vers.c) into
563  * prison0 by a sysinit and is inherited by child jails if not changed at jail
564  * creation, so we always return the value from the current prison data.
565  */
566 static int
567 sysctl_osreldate(SYSCTL_HANDLER_ARGS)
568 {
569 	struct prison *pr;
570 
571 	pr = req->td->td_ucred->cr_prison;
572 	return (SYSCTL_OUT(req, &pr->pr_osreldate, sizeof(pr->pr_osreldate)));
573 
574 }
575 
576 /*
577  * NOTICE: The *userland* release date is available in
578  * /usr/include/osreldate.h
579  */
580 SYSCTL_PROC(_kern, KERN_OSRELDATE, osreldate,
581     CTLTYPE_INT | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
582     NULL, 0, sysctl_osreldate, "I", "Kernel release date");
583 
584 /*
585  * The build-id is copied from the ELF section .note.gnu.build-id.  The linker
586  * script defines two variables to expose the beginning and end.  LLVM
587  * currently uses a SHA-1 hash, but other formats can be supported by checking
588  * the length of the section.
589  */
590 
591 extern char __build_id_start[];
592 extern char __build_id_end[];
593 
594 #define	BUILD_ID_HEADER_LEN	0x10
595 #define	BUILD_ID_HASH_MAXLEN	0x14
596 
597 static int
598 sysctl_build_id(SYSCTL_HANDLER_ARGS)
599 {
600 	uintptr_t sectionlen = (uintptr_t)(__build_id_end - __build_id_start);
601 	int hashlen;
602 	char buf[2*BUILD_ID_HASH_MAXLEN+1];
603 
604 	/*
605 	 * The ELF note section has a four byte length for the vendor name,
606 	 * four byte length for the value, and a four byte vendor specific
607 	 * type.  The name for the build id is "GNU\0".  We skip the first 16
608 	 * bytes to read the build hash.  We will return the remaining bytes up
609 	 * to 20 (SHA-1) hash size.  If the hash happens to be a custom number
610 	 * of bytes we will pad the value with zeros, as the section should be
611 	 * four byte aligned.
612 	 */
613 	if (sectionlen <= BUILD_ID_HEADER_LEN ||
614 	    sectionlen > (BUILD_ID_HEADER_LEN + BUILD_ID_HASH_MAXLEN)) {
615 		return (ENOENT);
616 	}
617 
618 	hashlen = sectionlen - BUILD_ID_HEADER_LEN;
619 	for (int i = 0; i < hashlen; i++) {
620 		uint8_t c = __build_id_start[i+BUILD_ID_HEADER_LEN];
621 		snprintf(&buf[2*i], 3, "%02x", c);
622 	}
623 
624 	return (SYSCTL_OUT(req, buf, strlen(buf) + 1));
625 }
626 
627 SYSCTL_PROC(_kern, OID_AUTO, build_id,
628     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
629     NULL, 0, sysctl_build_id, "A", "Operating system build-id");
630 
631 SYSCTL_NODE(_kern, OID_AUTO, features, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
632     "Kernel Features");
633 
634 #ifdef COMPAT_FREEBSD4
635 FEATURE(compat_freebsd4, "Compatible with FreeBSD 4");
636 #endif
637 
638 #ifdef COMPAT_FREEBSD5
639 FEATURE(compat_freebsd5, "Compatible with FreeBSD 5");
640 #endif
641 
642 #ifdef COMPAT_FREEBSD6
643 FEATURE(compat_freebsd6, "Compatible with FreeBSD 6");
644 #endif
645 
646 #ifdef COMPAT_FREEBSD7
647 FEATURE(compat_freebsd7, "Compatible with FreeBSD 7");
648 #endif
649 
650 #ifdef COMPAT_FREEBSD8
651 FEATURE(compat_freebsd8, "Compatible with FreeBSD 8");
652 #endif
653 
654 #ifdef COMPAT_FREEBSD9
655 FEATURE(compat_freebsd9, "Compatible with FreeBSD 9");
656 #endif
657 
658 #ifdef COMPAT_FREEBSD10
659 FEATURE(compat_freebsd10, "Compatible with FreeBSD 10");
660 #endif
661 
662 #ifdef COMPAT_FREEBSD11
663 FEATURE(compat_freebsd11, "Compatible with FreeBSD 11");
664 #endif
665 
666 #ifdef COMPAT_FREEBSD12
667 FEATURE(compat_freebsd12, "Compatible with FreeBSD 12");
668 #endif
669 
670 #ifdef COMPAT_FREEBSD13
671 FEATURE(compat_freebsd13, "Compatible with FreeBSD 13");
672 #endif
673 
674 #ifdef COMPAT_FREEBSD14
675 FEATURE(compat_freebsd14, "Compatible with FreeBSD 14");
676 #endif
677 
678 /*
679  * This is really cheating.  These actually live in the libc, something
680  * which I'm not quite sure is a good idea anyway, but in order for
681  * getnext and friends to actually work, we define dummies here.
682  *
683  * XXXRW: These probably should be CTLFLAG_CAPRD.
684  */
685 SYSCTL_STRING(_user, USER_CS_PATH, cs_path, CTLFLAG_RD,
686     "", 0, "PATH that finds all the standard utilities");
687 SYSCTL_INT(_user, USER_BC_BASE_MAX, bc_base_max, CTLFLAG_RD,
688     SYSCTL_NULL_INT_PTR, 0, "Max ibase/obase values in bc(1)");
689 SYSCTL_INT(_user, USER_BC_DIM_MAX, bc_dim_max, CTLFLAG_RD,
690     SYSCTL_NULL_INT_PTR, 0, "Max array size in bc(1)");
691 SYSCTL_INT(_user, USER_BC_SCALE_MAX, bc_scale_max, CTLFLAG_RD,
692     SYSCTL_NULL_INT_PTR, 0, "Max scale value in bc(1)");
693 SYSCTL_INT(_user, USER_BC_STRING_MAX, bc_string_max, CTLFLAG_RD,
694     SYSCTL_NULL_INT_PTR, 0, "Max string length in bc(1)");
695 SYSCTL_INT(_user, USER_COLL_WEIGHTS_MAX, coll_weights_max, CTLFLAG_RD,
696     SYSCTL_NULL_INT_PTR, 0, "Maximum number of weights assigned to an LC_COLLATE locale entry");
697 SYSCTL_INT(_user, USER_EXPR_NEST_MAX, expr_nest_max, CTLFLAG_RD,
698     SYSCTL_NULL_INT_PTR, 0, "");
699 SYSCTL_INT(_user, USER_LINE_MAX, line_max, CTLFLAG_RD,
700     SYSCTL_NULL_INT_PTR, 0, "Max length (bytes) of a text-processing utility's input line");
701 SYSCTL_INT(_user, USER_RE_DUP_MAX, re_dup_max, CTLFLAG_RD,
702     SYSCTL_NULL_INT_PTR, 0, "Maximum number of repeats of a regexp permitted");
703 SYSCTL_INT(_user, USER_POSIX2_VERSION, posix2_version, CTLFLAG_RD,
704     SYSCTL_NULL_INT_PTR, 0,
705     "The version of POSIX 1003.2 with which the system attempts to comply");
706 SYSCTL_INT(_user, USER_POSIX2_C_BIND, posix2_c_bind, CTLFLAG_RD,
707     SYSCTL_NULL_INT_PTR, 0, "Whether C development supports the C bindings option");
708 SYSCTL_INT(_user, USER_POSIX2_C_DEV, posix2_c_dev, CTLFLAG_RD,
709     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the C development utilities option");
710 SYSCTL_INT(_user, USER_POSIX2_CHAR_TERM, posix2_char_term, CTLFLAG_RD,
711     SYSCTL_NULL_INT_PTR, 0, "");
712 SYSCTL_INT(_user, USER_POSIX2_FORT_DEV, posix2_fort_dev, CTLFLAG_RD,
713     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN development utilities");
714 SYSCTL_INT(_user, USER_POSIX2_FORT_RUN, posix2_fort_run, CTLFLAG_RD,
715     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN runtime utilities");
716 SYSCTL_INT(_user, USER_POSIX2_LOCALEDEF, posix2_localedef, CTLFLAG_RD,
717     SYSCTL_NULL_INT_PTR, 0, "Whether system supports creation of locales");
718 SYSCTL_INT(_user, USER_POSIX2_SW_DEV, posix2_sw_dev, CTLFLAG_RD,
719     SYSCTL_NULL_INT_PTR, 0, "Whether system supports software development utilities");
720 SYSCTL_INT(_user, USER_POSIX2_UPE, posix2_upe, CTLFLAG_RD,
721     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the user portability utilities");
722 SYSCTL_INT(_user, USER_STREAM_MAX, stream_max, CTLFLAG_RD,
723     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of streams a process may have open at one time");
724 SYSCTL_INT(_user, USER_TZNAME_MAX, tzname_max, CTLFLAG_RD,
725     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of types supported for timezone names");
726 
727 static char localbase[MAXPATHLEN] = "";
728 
729 SYSCTL_STRING(_user, USER_LOCALBASE, localbase, CTLFLAG_RWTUN,
730     localbase, sizeof(localbase), "Prefix used to install and locate add-on packages");
731 
732 #include <sys/vnode.h>
733 SYSCTL_INT(_debug_sizeof, OID_AUTO, vnode, CTLFLAG_RD,
734     SYSCTL_NULL_INT_PTR, sizeof(struct vnode), "sizeof(struct vnode)");
735 
736 SYSCTL_INT(_debug_sizeof, OID_AUTO, proc, CTLFLAG_RD,
737     SYSCTL_NULL_INT_PTR, sizeof(struct proc), "sizeof(struct proc)");
738 
739 static int
740 sysctl_kern_pid_max(SYSCTL_HANDLER_ARGS)
741 {
742 	int error, pm;
743 
744 	pm = pid_max;
745 	error = sysctl_handle_int(oidp, &pm, 0, req);
746 	if (error || !req->newptr)
747 		return (error);
748 	sx_xlock(&proctree_lock);
749 	sx_xlock(&allproc_lock);
750 
751 	/*
752 	 * Only permit the values less then PID_MAX.
753 	 * As a safety measure, do not allow to limit the pid_max too much.
754 	 */
755 	if (pm < 300 || pm > PID_MAX)
756 		error = EINVAL;
757 	else
758 		pid_max = pm;
759 	sx_xunlock(&allproc_lock);
760 	sx_xunlock(&proctree_lock);
761 	return (error);
762 }
763 SYSCTL_PROC(_kern, OID_AUTO, pid_max, CTLTYPE_INT |
764     CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
765     0, 0, sysctl_kern_pid_max, "I", "Maximum allowed pid");
766 
767 SYSCTL_INT(_kern, OID_AUTO, pid_max_limit, CTLFLAG_RD,
768     SYSCTL_NULL_INT_PTR, PID_MAX,
769     "Maximum allowed pid (kern.pid_max) top limit");
770 
771 #include <sys/bio.h>
772 #include <sys/buf.h>
773 SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
774     SYSCTL_NULL_INT_PTR, sizeof(struct bio), "sizeof(struct bio)");
775 SYSCTL_INT(_debug_sizeof, OID_AUTO, buf, CTLFLAG_RD,
776     SYSCTL_NULL_INT_PTR, sizeof(struct buf), "sizeof(struct buf)");
777 
778 #include <sys/user.h>
779 SYSCTL_INT(_debug_sizeof, OID_AUTO, kinfo_proc, CTLFLAG_RD,
780     SYSCTL_NULL_INT_PTR, sizeof(struct kinfo_proc), "sizeof(struct kinfo_proc)");
781 
782 /* Used by kernel debuggers. */
783 const int pcb_size = sizeof(struct pcb);
784 SYSCTL_INT(_debug_sizeof, OID_AUTO, pcb, CTLFLAG_RD,
785     SYSCTL_NULL_INT_PTR, sizeof(struct pcb), "sizeof(struct pcb)");
786 
787 /* XXX compatibility, remove for 6.0 */
788 #include <sys/imgact.h>
789 #include <sys/imgact_elf.h>
790 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
791     &__elfN(fallback_brand), sizeof(__elfN(fallback_brand)),
792     "compatibility for kern.fallback_elf_brand");
793