xref: /freebsd/sys/kern/kern_mib.c (revision 97759ccc715c4b365432c16d763c50eecfcb1100)
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  *	@(#)kern_sysctl.c	8.4 (Berkeley) 4/14/94
38  */
39 
40 #include <sys/cdefs.h>
41 #include "opt_posix.h"
42 #include "opt_config.h"
43 
44 #include <sys/param.h>
45 #include <sys/boot.h>
46 #include <sys/elf.h>
47 #include <sys/jail.h>
48 #include <sys/kernel.h>
49 #include <sys/limits.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/proc.h>
53 #include <sys/random.h>
54 #include <sys/sbuf.h>
55 #include <sys/smp.h>
56 #include <sys/sx.h>
57 #include <sys/sysent.h>
58 #include <sys/vmmeter.h>
59 #include <sys/sysctl.h>
60 #include <sys/systm.h>
61 #include <sys/unistd.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|CTLFLAG_MPSAFE,
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|CTLFLAG_MPSAFE,
104     version, 0, "Kernel version");
105 
106 SYSCTL_STRING(_kern, OID_AUTO, compiler_version, CTLFLAG_RD|CTLFLAG_MPSAFE,
107     compiler_version, 0, "Version of compiler used to compile kernel");
108 
109 SYSCTL_STRING(_kern, KERN_OSTYPE, ostype, CTLFLAG_RD|CTLFLAG_MPSAFE|
110     CTLFLAG_CAPRD, 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 | CTLFLAG_MPSAFE,
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 
186 	len = MIN(req->oldlen, sizeof(buf));
187 	read_random(buf, len);
188 	return (SYSCTL_OUT(req, buf, len));
189 }
190 
191 SYSCTL_PROC(_kern, KERN_ARND, arandom,
192     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD, NULL, 0,
193     sysctl_kern_arnd, "", "arc4rand");
194 
195 static int
196 sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
197 {
198 	u_long val, p;
199 
200 	p = SIZE_T_MAX >> PAGE_SHIFT;
201 	if (physmem < p)
202 		p = physmem;
203 	val = ctob(p);
204 	return (sysctl_handle_long(oidp, &val, 0, req));
205 }
206 SYSCTL_PROC(_hw, HW_PHYSMEM, physmem,
207     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
208     sysctl_hw_physmem, "LU",
209     "Amount of physical memory (in bytes)");
210 
211 static int
212 sysctl_hw_realmem(SYSCTL_HANDLER_ARGS)
213 {
214 	u_long val, p;
215 
216 	p = SIZE_T_MAX >> PAGE_SHIFT;
217 	if (realmem < p)
218 		p = realmem;
219 	val = ctob(p);
220 	return (sysctl_handle_long(oidp, &val, 0, req));
221 }
222 SYSCTL_PROC(_hw, HW_REALMEM, realmem,
223     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
224     sysctl_hw_realmem, "LU",
225     "Amount of memory (in bytes) reported by the firmware");
226 
227 static int
228 sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
229 {
230 	u_long val, p, p1;
231 
232 	p1 = physmem - vm_wire_count();
233 	p = SIZE_T_MAX >> PAGE_SHIFT;
234 	if (p1 < p)
235 		p = p1;
236 	val = ctob(p);
237 	return (sysctl_handle_long(oidp, &val, 0, req));
238 }
239 SYSCTL_PROC(_hw, HW_USERMEM, usermem,
240     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
241     sysctl_hw_usermem, "LU",
242     "Amount of memory (in bytes) which is not wired");
243 
244 SYSCTL_LONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &physmem, 0,
245     "Amount of physical memory (in pages)");
246 
247 u_long pagesizes[MAXPAGESIZES] = { PAGE_SIZE };
248 
249 static int
250 sysctl_hw_pagesizes(SYSCTL_HANDLER_ARGS)
251 {
252 	int error;
253 	size_t len;
254 #ifdef SCTL_MASK32
255 	int i;
256 	uint32_t pagesizes32[MAXPAGESIZES];
257 
258 	if (req->flags & SCTL_MASK32) {
259 		/*
260 		 * Recreate the "pagesizes" array with 32-bit elements.
261 		 * Truncate any page size greater than UINT32_MAX to zero,
262 		 * which assumes that page sizes are powers of two.
263 		 */
264 		for (i = 0; i < MAXPAGESIZES; i++)
265 			pagesizes32[i] = (uint32_t)pagesizes[i];
266 
267 		len = sizeof(pagesizes32);
268 		if (len > req->oldlen && req->oldptr != NULL)
269 			len = req->oldlen;
270 		error = SYSCTL_OUT(req, pagesizes32, len);
271 	} else
272 #endif
273 	{
274 		len = sizeof(pagesizes);
275 		if (len > req->oldlen && req->oldptr != NULL)
276 			len = req->oldlen;
277 		error = SYSCTL_OUT(req, pagesizes, len);
278 	}
279 	return (error);
280 }
281 SYSCTL_PROC(_hw, OID_AUTO, pagesizes,
282     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
283     sysctl_hw_pagesizes, "S,pagesizes",
284     "Supported page sizes");
285 
286 int adaptive_machine_arch = 1;
287 SYSCTL_INT(_debug, OID_AUTO, adaptive_machine_arch, CTLFLAG_RW,
288     &adaptive_machine_arch, 1,
289     "Adapt reported machine architecture to the ABI of the binary");
290 
291 static const char *
292 proc_machine_arch(struct proc *p)
293 {
294 
295 	if (p->p_sysent->sv_machine_arch != NULL)
296 		return (p->p_sysent->sv_machine_arch(p));
297 #ifdef COMPAT_FREEBSD32
298 	if (SV_PROC_FLAG(p, SV_ILP32))
299 		return (MACHINE_ARCH32);
300 #endif
301 	return (MACHINE_ARCH);
302 }
303 
304 static int
305 sysctl_hw_machine_arch(SYSCTL_HANDLER_ARGS)
306 {
307 	const char *machine_arch;
308 
309 	if (adaptive_machine_arch)
310 		machine_arch = proc_machine_arch(curproc);
311 	else
312 		machine_arch = MACHINE_ARCH;
313 	return (SYSCTL_OUT(req, machine_arch, strlen(machine_arch) + 1));
314 }
315 SYSCTL_PROC(_hw, HW_MACHINE_ARCH, machine_arch, CTLTYPE_STRING | CTLFLAG_RD |
316     CTLFLAG_CAPRD | CTLFLAG_MPSAFE, NULL, 0, sysctl_hw_machine_arch, "A",
317     "System architecture");
318 
319 #ifdef COMPAT_FREEBSD32
320 #include <compat/freebsd32/freebsd32_util.h>
321 #endif
322 
323 static int
324 sysctl_kern_supported_archs(SYSCTL_HANDLER_ARGS)
325 {
326 	const char *supported_archs;
327 
328 	supported_archs =
329 #ifdef COMPAT_FREEBSD32
330 	    compat_freebsd_32bit ? MACHINE_ARCH " " MACHINE_ARCH32 :
331 #endif
332 	    MACHINE_ARCH;
333 	return (SYSCTL_OUT(req, supported_archs, strlen(supported_archs) + 1));
334 }
335 SYSCTL_PROC(_kern, OID_AUTO, supported_archs, CTLFLAG_RD | CTLFLAG_MPSAFE |
336     CTLFLAG_CAPRD | CTLTYPE_STRING, NULL, 0, sysctl_kern_supported_archs, "A",
337     "Supported architectures for binaries");
338 
339 static int
340 sysctl_hostname(SYSCTL_HANDLER_ARGS)
341 {
342 	struct prison *pr, *cpr;
343 	size_t pr_offset;
344 	char tmpname[MAXHOSTNAMELEN];
345 	int descend, error, len;
346 
347 	/*
348 	 * This function can set: hostname domainname hostuuid.
349 	 * Keep that in mind when comments say "hostname".
350 	 */
351 	pr_offset = (size_t)arg1;
352 	len = arg2;
353 	KASSERT(len <= sizeof(tmpname),
354 	    ("length %d too long for %s", len, __func__));
355 
356 	/*
357 	 * Make a local copy of hostname to get/set so we don't have to hold
358 	 * the jail mutex during the sysctl copyin/copyout activities.
359 	 */
360 	pr = req->td->td_ucred->cr_prison;
361 	mtx_lock(&pr->pr_mtx);
362 	bcopy((char *)pr + pr_offset, tmpname, len);
363 	mtx_unlock(&pr->pr_mtx);
364 
365 	error = sysctl_handle_string(oidp, tmpname, len, req);
366 	if (error != 0 || req->newptr == NULL)
367 		return (error);
368 
369 	/*
370 	 * Copy the locally set hostname to all jails that share
371 	 * this host info.
372 	 */
373 	sx_slock(&allprison_lock);
374 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME))
375 		error = EPERM;
376 	else {
377 		while (!(pr->pr_flags & PR_HOST))
378 			pr = pr->pr_parent;
379 		mtx_lock(&pr->pr_mtx);
380 		bcopy(tmpname, (char *)pr + pr_offset, len);
381 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
382 			if (cpr->pr_flags & PR_HOST)
383 				descend = 0;
384 			else
385 				bcopy(tmpname, (char *)cpr + pr_offset, len);
386 		mtx_unlock(&pr->pr_mtx);
387 	}
388 	sx_sunlock(&allprison_lock);
389 	return (error);
390 }
391 
392 SYSCTL_PROC(_kern, KERN_HOSTNAME, hostname,
393     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
394     (void *)(offsetof(struct prison, pr_hostname)), MAXHOSTNAMELEN,
395     sysctl_hostname, "A", "Hostname");
396 SYSCTL_PROC(_kern, KERN_NISDOMAINNAME, domainname,
397     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
398     (void *)(offsetof(struct prison, pr_domainname)), MAXHOSTNAMELEN,
399     sysctl_hostname, "A", "Name of the current YP/NIS domain");
400 SYSCTL_PROC(_kern, KERN_HOSTUUID, hostuuid,
401     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
402     (void *)(offsetof(struct prison, pr_hostuuid)), HOSTUUIDLEN,
403     sysctl_hostname, "A", "Host UUID");
404 
405 static int	regression_securelevel_nonmonotonic = 0;
406 
407 #ifdef REGRESSION
408 SYSCTL_INT(_regression, OID_AUTO, securelevel_nonmonotonic, CTLFLAG_RW,
409     &regression_securelevel_nonmonotonic, 0, "securelevel may be lowered");
410 #endif
411 
412 static int
413 sysctl_kern_securelvl(SYSCTL_HANDLER_ARGS)
414 {
415 	struct prison *pr, *cpr;
416 	int descend, error, level;
417 
418 	pr = req->td->td_ucred->cr_prison;
419 
420 	/*
421 	 * Reading the securelevel is easy, since the current jail's level
422 	 * is known to be at least as secure as any higher levels.  Perform
423 	 * a lockless read since the securelevel is an integer.
424 	 */
425 	level = pr->pr_securelevel;
426 	error = sysctl_handle_int(oidp, &level, 0, req);
427 	if (error || !req->newptr)
428 		return (error);
429 	/* Permit update only if the new securelevel exceeds the old. */
430 	sx_slock(&allprison_lock);
431 	mtx_lock(&pr->pr_mtx);
432 	if (!regression_securelevel_nonmonotonic &&
433 	    level < pr->pr_securelevel) {
434 		mtx_unlock(&pr->pr_mtx);
435 		sx_sunlock(&allprison_lock);
436 		return (EPERM);
437 	}
438 	pr->pr_securelevel = level;
439 	/*
440 	 * Set all child jails to be at least this level, but do not lower
441 	 * them (even if regression_securelevel_nonmonotonic).
442 	 */
443 	FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend) {
444 		if (cpr->pr_securelevel < level)
445 			cpr->pr_securelevel = level;
446 	}
447 	mtx_unlock(&pr->pr_mtx);
448 	sx_sunlock(&allprison_lock);
449 	return (error);
450 }
451 
452 SYSCTL_PROC(_kern, KERN_SECURELVL, securelevel,
453     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE, 0, 0,
454     sysctl_kern_securelvl, "I",
455     "Current secure level");
456 
457 #ifdef INCLUDE_CONFIG_FILE
458 /* Actual kernel configuration options. */
459 extern char kernconfstring[];
460 
461 SYSCTL_STRING(_kern, OID_AUTO, conftxt, CTLFLAG_RD | CTLFLAG_MPSAFE,
462     kernconfstring, 0, "Kernel configuration file");
463 #endif
464 
465 static int
466 sysctl_hostid(SYSCTL_HANDLER_ARGS)
467 {
468 	struct prison *pr, *cpr;
469 	u_long tmpid;
470 	int descend, error;
471 
472 	/*
473 	 * Like sysctl_hostname, except it operates on a u_long
474 	 * instead of a string, and is used only for hostid.
475 	 */
476 	pr = req->td->td_ucred->cr_prison;
477 	mtx_lock(&pr->pr_mtx);
478 	tmpid = pr->pr_hostid;
479 	mtx_unlock(&pr->pr_mtx);
480 
481 	error = sysctl_handle_long(oidp, &tmpid, 0, req);
482 	if (error != 0 || req->newptr == NULL)
483 		return (error);
484 
485 	sx_slock(&allprison_lock);
486 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME))
487 		error = EPERM;
488 	else {
489 		while (!(pr->pr_flags & PR_HOST))
490 			pr = pr->pr_parent;
491 		mtx_lock(&pr->pr_mtx);
492 		pr->pr_hostid = tmpid;
493 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
494 			if (cpr->pr_flags & PR_HOST)
495 				descend = 0;
496 			else
497 				cpr->pr_hostid = tmpid;
498 		mtx_unlock(&pr->pr_mtx);
499 	}
500 	sx_sunlock(&allprison_lock);
501 	return (error);
502 }
503 
504 SYSCTL_PROC(_kern, KERN_HOSTID, hostid,
505     CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
506     NULL, 0, sysctl_hostid, "LU", "Host ID");
507 
508 static struct mtx bootid_lk;
509 MTX_SYSINIT(bootid_lock, &bootid_lk, "bootid generator lock", MTX_DEF);
510 
511 static int
512 sysctl_bootid(SYSCTL_HANDLER_ARGS)
513 {
514 	static uint8_t boot_id[16];
515 	static bool initialized = false;
516 
517 	mtx_lock(&bootid_lk);
518 	if (!initialized) {
519 		if (!is_random_seeded()) {
520 			mtx_unlock(&bootid_lk);
521 			return (ENXIO);
522 		}
523 		arc4random_buf(boot_id, sizeof(boot_id));
524 		initialized = true;
525 	}
526 	mtx_unlock(&bootid_lk);
527 
528 	return (SYSCTL_OUT(req, boot_id, sizeof(boot_id)));
529 }
530 SYSCTL_PROC(_kern, OID_AUTO, boot_id,
531     CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
532     NULL, 0, sysctl_bootid, "", "Random boot ID");
533 
534 /*
535  * The osrelease string is copied from the global (osrelease in vers.c) into
536  * prison0 by a sysinit and is inherited by child jails if not changed at jail
537  * creation, so we always return the copy from the current prison data.
538  */
539 static int
540 sysctl_osrelease(SYSCTL_HANDLER_ARGS)
541 {
542 	struct prison *pr;
543 
544 	pr = req->td->td_ucred->cr_prison;
545 	return (SYSCTL_OUT(req, pr->pr_osrelease, strlen(pr->pr_osrelease) + 1));
546 
547 }
548 
549 SYSCTL_PROC(_kern, KERN_OSRELEASE, osrelease,
550     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
551     NULL, 0, sysctl_osrelease, "A", "Operating system release");
552 
553 /*
554  * The osreldate number is copied from the global (osreldate in vers.c) into
555  * prison0 by a sysinit and is inherited by child jails if not changed at jail
556  * creation, so we always return the value from the current prison data.
557  */
558 static int
559 sysctl_osreldate(SYSCTL_HANDLER_ARGS)
560 {
561 	struct prison *pr;
562 
563 	pr = req->td->td_ucred->cr_prison;
564 	return (SYSCTL_OUT(req, &pr->pr_osreldate, sizeof(pr->pr_osreldate)));
565 
566 }
567 
568 /*
569  * NOTICE: The *userland* release date is available in
570  * /usr/include/osreldate.h
571  */
572 SYSCTL_PROC(_kern, KERN_OSRELDATE, osreldate,
573     CTLTYPE_INT | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
574     NULL, 0, sysctl_osreldate, "I", "Kernel release date");
575 
576 /*
577  * The build-id is copied from the ELF section .note.gnu.build-id.  The linker
578  * script defines two variables to expose the beginning and end.  LLVM
579  * currently uses a SHA-1 hash, but other formats can be supported by checking
580  * the length of the section.
581  */
582 
583 extern char __build_id_start[];
584 extern char __build_id_end[];
585 
586 #define	BUILD_ID_HEADER_LEN	0x10
587 #define	BUILD_ID_HASH_MAXLEN	0x14
588 
589 static int
590 sysctl_build_id(SYSCTL_HANDLER_ARGS)
591 {
592 	uintptr_t sectionlen = (uintptr_t)(__build_id_end - __build_id_start);
593 	int hashlen;
594 	char buf[2*BUILD_ID_HASH_MAXLEN+1];
595 
596 	/*
597 	 * The ELF note section has a four byte length for the vendor name,
598 	 * four byte length for the value, and a four byte vendor specific
599 	 * type.  The name for the build id is "GNU\0".  We skip the first 16
600 	 * bytes to read the build hash.  We will return the remaining bytes up
601 	 * to 20 (SHA-1) hash size.  If the hash happens to be a custom number
602 	 * of bytes we will pad the value with zeros, as the section should be
603 	 * four byte aligned.
604 	 */
605 	if (sectionlen <= BUILD_ID_HEADER_LEN ||
606 	    sectionlen > (BUILD_ID_HEADER_LEN + BUILD_ID_HASH_MAXLEN)) {
607 		return (ENOENT);
608 	}
609 
610 	hashlen = sectionlen - BUILD_ID_HEADER_LEN;
611 	for (int i = 0; i < hashlen; i++) {
612 		uint8_t c = __build_id_start[i+BUILD_ID_HEADER_LEN];
613 		snprintf(&buf[2*i], 3, "%02x", c);
614 	}
615 
616 	return (SYSCTL_OUT(req, buf, strlen(buf) + 1));
617 }
618 
619 SYSCTL_PROC(_kern, OID_AUTO, build_id,
620     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
621     NULL, 0, sysctl_build_id, "A", "Operating system build-id");
622 
623 SYSCTL_NODE(_kern, OID_AUTO, features, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
624     "Kernel Features");
625 
626 #ifdef COMPAT_FREEBSD4
627 FEATURE(compat_freebsd4, "Compatible with FreeBSD 4");
628 #endif
629 
630 #ifdef COMPAT_FREEBSD5
631 FEATURE(compat_freebsd5, "Compatible with FreeBSD 5");
632 #endif
633 
634 #ifdef COMPAT_FREEBSD6
635 FEATURE(compat_freebsd6, "Compatible with FreeBSD 6");
636 #endif
637 
638 #ifdef COMPAT_FREEBSD7
639 FEATURE(compat_freebsd7, "Compatible with FreeBSD 7");
640 #endif
641 
642 #ifdef COMPAT_FREEBSD8
643 FEATURE(compat_freebsd8, "Compatible with FreeBSD 8");
644 #endif
645 
646 #ifdef COMPAT_FREEBSD9
647 FEATURE(compat_freebsd9, "Compatible with FreeBSD 9");
648 #endif
649 
650 #ifdef COMPAT_FREEBSD10
651 FEATURE(compat_freebsd10, "Compatible with FreeBSD 10");
652 #endif
653 
654 #ifdef COMPAT_FREEBSD11
655 FEATURE(compat_freebsd11, "Compatible with FreeBSD 11");
656 #endif
657 
658 #ifdef COMPAT_FREEBSD12
659 FEATURE(compat_freebsd12, "Compatible with FreeBSD 12");
660 #endif
661 
662 #ifdef COMPAT_FREEBSD13
663 FEATURE(compat_freebsd13, "Compatible with FreeBSD 13");
664 #endif
665 
666 #ifdef COMPAT_FREEBSD14
667 FEATURE(compat_freebsd14, "Compatible with FreeBSD 14");
668 #endif
669 
670 /*
671  * This is really cheating.  These actually live in the libc, something
672  * which I'm not quite sure is a good idea anyway, but in order for
673  * getnext and friends to actually work, we define dummies here.
674  *
675  * XXXRW: These probably should be CTLFLAG_CAPRD.
676  */
677 SYSCTL_STRING(_user, USER_CS_PATH, cs_path, CTLFLAG_RD,
678     "", 0, "PATH that finds all the standard utilities");
679 SYSCTL_INT(_user, USER_BC_BASE_MAX, bc_base_max, CTLFLAG_RD,
680     SYSCTL_NULL_INT_PTR, 0, "Max ibase/obase values in bc(1)");
681 SYSCTL_INT(_user, USER_BC_DIM_MAX, bc_dim_max, CTLFLAG_RD,
682     SYSCTL_NULL_INT_PTR, 0, "Max array size in bc(1)");
683 SYSCTL_INT(_user, USER_BC_SCALE_MAX, bc_scale_max, CTLFLAG_RD,
684     SYSCTL_NULL_INT_PTR, 0, "Max scale value in bc(1)");
685 SYSCTL_INT(_user, USER_BC_STRING_MAX, bc_string_max, CTLFLAG_RD,
686     SYSCTL_NULL_INT_PTR, 0, "Max string length in bc(1)");
687 SYSCTL_INT(_user, USER_COLL_WEIGHTS_MAX, coll_weights_max, CTLFLAG_RD,
688     SYSCTL_NULL_INT_PTR, 0, "Maximum number of weights assigned to an LC_COLLATE locale entry");
689 SYSCTL_INT(_user, USER_EXPR_NEST_MAX, expr_nest_max, CTLFLAG_RD,
690     SYSCTL_NULL_INT_PTR, 0, "");
691 SYSCTL_INT(_user, USER_LINE_MAX, line_max, CTLFLAG_RD,
692     SYSCTL_NULL_INT_PTR, 0, "Max length (bytes) of a text-processing utility's input line");
693 SYSCTL_INT(_user, USER_RE_DUP_MAX, re_dup_max, CTLFLAG_RD,
694     SYSCTL_NULL_INT_PTR, 0, "Maximum number of repeats of a regexp permitted");
695 SYSCTL_INT(_user, USER_POSIX2_VERSION, posix2_version, CTLFLAG_RD,
696     SYSCTL_NULL_INT_PTR, 0,
697     "The version of POSIX 1003.2 with which the system attempts to comply");
698 SYSCTL_INT(_user, USER_POSIX2_C_BIND, posix2_c_bind, CTLFLAG_RD,
699     SYSCTL_NULL_INT_PTR, 0, "Whether C development supports the C bindings option");
700 SYSCTL_INT(_user, USER_POSIX2_C_DEV, posix2_c_dev, CTLFLAG_RD,
701     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the C development utilities option");
702 SYSCTL_INT(_user, USER_POSIX2_CHAR_TERM, posix2_char_term, CTLFLAG_RD,
703     SYSCTL_NULL_INT_PTR, 0, "");
704 SYSCTL_INT(_user, USER_POSIX2_FORT_DEV, posix2_fort_dev, CTLFLAG_RD,
705     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN development utilities");
706 SYSCTL_INT(_user, USER_POSIX2_FORT_RUN, posix2_fort_run, CTLFLAG_RD,
707     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN runtime utilities");
708 SYSCTL_INT(_user, USER_POSIX2_LOCALEDEF, posix2_localedef, CTLFLAG_RD,
709     SYSCTL_NULL_INT_PTR, 0, "Whether system supports creation of locales");
710 SYSCTL_INT(_user, USER_POSIX2_SW_DEV, posix2_sw_dev, CTLFLAG_RD,
711     SYSCTL_NULL_INT_PTR, 0, "Whether system supports software development utilities");
712 SYSCTL_INT(_user, USER_POSIX2_UPE, posix2_upe, CTLFLAG_RD,
713     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the user portability utilities");
714 SYSCTL_INT(_user, USER_STREAM_MAX, stream_max, CTLFLAG_RD,
715     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of streams a process may have open at one time");
716 SYSCTL_INT(_user, USER_TZNAME_MAX, tzname_max, CTLFLAG_RD,
717     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of types supported for timezone names");
718 
719 static char localbase[MAXPATHLEN] = "";
720 
721 SYSCTL_STRING(_user, USER_LOCALBASE, localbase, CTLFLAG_RWTUN,
722     localbase, sizeof(localbase), "Prefix used to install and locate add-on packages");
723 
724 #include <sys/vnode.h>
725 SYSCTL_INT(_debug_sizeof, OID_AUTO, vnode, CTLFLAG_RD,
726     SYSCTL_NULL_INT_PTR, sizeof(struct vnode), "sizeof(struct vnode)");
727 
728 SYSCTL_INT(_debug_sizeof, OID_AUTO, proc, CTLFLAG_RD,
729     SYSCTL_NULL_INT_PTR, sizeof(struct proc), "sizeof(struct proc)");
730 
731 static int
732 sysctl_kern_pid_max(SYSCTL_HANDLER_ARGS)
733 {
734 	int error, pm;
735 
736 	pm = pid_max;
737 	error = sysctl_handle_int(oidp, &pm, 0, req);
738 	if (error || !req->newptr)
739 		return (error);
740 	sx_xlock(&proctree_lock);
741 	sx_xlock(&allproc_lock);
742 
743 	/*
744 	 * Only permit the values less then PID_MAX.
745 	 * As a safety measure, do not allow to limit the pid_max too much.
746 	 */
747 	if (pm < 300 || pm > PID_MAX)
748 		error = EINVAL;
749 	else
750 		pid_max = pm;
751 	sx_xunlock(&allproc_lock);
752 	sx_xunlock(&proctree_lock);
753 	return (error);
754 }
755 SYSCTL_PROC(_kern, OID_AUTO, pid_max, CTLTYPE_INT |
756     CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
757     0, 0, sysctl_kern_pid_max, "I", "Maximum allowed pid");
758 
759 #include <sys/bio.h>
760 #include <sys/buf.h>
761 SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
762     SYSCTL_NULL_INT_PTR, sizeof(struct bio), "sizeof(struct bio)");
763 SYSCTL_INT(_debug_sizeof, OID_AUTO, buf, CTLFLAG_RD,
764     SYSCTL_NULL_INT_PTR, sizeof(struct buf), "sizeof(struct buf)");
765 
766 #include <sys/user.h>
767 SYSCTL_INT(_debug_sizeof, OID_AUTO, kinfo_proc, CTLFLAG_RD,
768     SYSCTL_NULL_INT_PTR, sizeof(struct kinfo_proc), "sizeof(struct kinfo_proc)");
769 
770 /* Used by kernel debuggers. */
771 const int pcb_size = sizeof(struct pcb);
772 SYSCTL_INT(_debug_sizeof, OID_AUTO, pcb, CTLFLAG_RD,
773     SYSCTL_NULL_INT_PTR, sizeof(struct pcb), "sizeof(struct pcb)");
774 
775 /* XXX compatibility, remove for 6.0 */
776 #include <sys/imgact.h>
777 #include <sys/imgact_elf.h>
778 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
779     &__elfN(fallback_brand), sizeof(__elfN(fallback_brand)),
780     "compatibility for kern.fallback_elf_brand");
781