xref: /freebsd/sys/kern/kern_mib.c (revision 5e3190f700637fcfc1a52daeaa4a031fdd2557c7)
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 #ifndef MACHINE_ARCHES
320 #ifdef COMPAT_FREEBSD32
321 #define	MACHINE_ARCHES	MACHINE_ARCH " " MACHINE_ARCH32
322 #else
323 #define	MACHINE_ARCHES	MACHINE_ARCH
324 #endif
325 #endif
326 
327 SYSCTL_STRING(_kern, OID_AUTO, supported_archs, CTLFLAG_RD | CTLFLAG_MPSAFE,
328     MACHINE_ARCHES, 0, "Supported architectures for binaries");
329 
330 static int
331 sysctl_hostname(SYSCTL_HANDLER_ARGS)
332 {
333 	struct prison *pr, *cpr;
334 	size_t pr_offset;
335 	char tmpname[MAXHOSTNAMELEN];
336 	int descend, error, len;
337 
338 	/*
339 	 * This function can set: hostname domainname hostuuid.
340 	 * Keep that in mind when comments say "hostname".
341 	 */
342 	pr_offset = (size_t)arg1;
343 	len = arg2;
344 	KASSERT(len <= sizeof(tmpname),
345 	    ("length %d too long for %s", len, __func__));
346 
347 	/*
348 	 * Make a local copy of hostname to get/set so we don't have to hold
349 	 * the jail mutex during the sysctl copyin/copyout activities.
350 	 */
351 	pr = req->td->td_ucred->cr_prison;
352 	mtx_lock(&pr->pr_mtx);
353 	bcopy((char *)pr + pr_offset, tmpname, len);
354 	mtx_unlock(&pr->pr_mtx);
355 
356 	error = sysctl_handle_string(oidp, tmpname, len, req);
357 	if (error != 0 || req->newptr == NULL)
358 		return (error);
359 
360 	/*
361 	 * Copy the locally set hostname to all jails that share
362 	 * this host info.
363 	 */
364 	sx_slock(&allprison_lock);
365 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME))
366 		error = EPERM;
367 	else {
368 		while (!(pr->pr_flags & PR_HOST))
369 			pr = pr->pr_parent;
370 		mtx_lock(&pr->pr_mtx);
371 		bcopy(tmpname, (char *)pr + pr_offset, len);
372 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
373 			if (cpr->pr_flags & PR_HOST)
374 				descend = 0;
375 			else
376 				bcopy(tmpname, (char *)cpr + pr_offset, len);
377 		mtx_unlock(&pr->pr_mtx);
378 	}
379 	sx_sunlock(&allprison_lock);
380 	return (error);
381 }
382 
383 SYSCTL_PROC(_kern, KERN_HOSTNAME, hostname,
384     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
385     (void *)(offsetof(struct prison, pr_hostname)), MAXHOSTNAMELEN,
386     sysctl_hostname, "A", "Hostname");
387 SYSCTL_PROC(_kern, KERN_NISDOMAINNAME, domainname,
388     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
389     (void *)(offsetof(struct prison, pr_domainname)), MAXHOSTNAMELEN,
390     sysctl_hostname, "A", "Name of the current YP/NIS domain");
391 SYSCTL_PROC(_kern, KERN_HOSTUUID, hostuuid,
392     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
393     (void *)(offsetof(struct prison, pr_hostuuid)), HOSTUUIDLEN,
394     sysctl_hostname, "A", "Host UUID");
395 
396 static int	regression_securelevel_nonmonotonic = 0;
397 
398 #ifdef REGRESSION
399 SYSCTL_INT(_regression, OID_AUTO, securelevel_nonmonotonic, CTLFLAG_RW,
400     &regression_securelevel_nonmonotonic, 0, "securelevel may be lowered");
401 #endif
402 
403 static int
404 sysctl_kern_securelvl(SYSCTL_HANDLER_ARGS)
405 {
406 	struct prison *pr, *cpr;
407 	int descend, error, level;
408 
409 	pr = req->td->td_ucred->cr_prison;
410 
411 	/*
412 	 * Reading the securelevel is easy, since the current jail's level
413 	 * is known to be at least as secure as any higher levels.  Perform
414 	 * a lockless read since the securelevel is an integer.
415 	 */
416 	level = pr->pr_securelevel;
417 	error = sysctl_handle_int(oidp, &level, 0, req);
418 	if (error || !req->newptr)
419 		return (error);
420 	/* Permit update only if the new securelevel exceeds the old. */
421 	sx_slock(&allprison_lock);
422 	mtx_lock(&pr->pr_mtx);
423 	if (!regression_securelevel_nonmonotonic &&
424 	    level < pr->pr_securelevel) {
425 		mtx_unlock(&pr->pr_mtx);
426 		sx_sunlock(&allprison_lock);
427 		return (EPERM);
428 	}
429 	pr->pr_securelevel = level;
430 	/*
431 	 * Set all child jails to be at least this level, but do not lower
432 	 * them (even if regression_securelevel_nonmonotonic).
433 	 */
434 	FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend) {
435 		if (cpr->pr_securelevel < level)
436 			cpr->pr_securelevel = level;
437 	}
438 	mtx_unlock(&pr->pr_mtx);
439 	sx_sunlock(&allprison_lock);
440 	return (error);
441 }
442 
443 SYSCTL_PROC(_kern, KERN_SECURELVL, securelevel,
444     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE, 0, 0,
445     sysctl_kern_securelvl, "I",
446     "Current secure level");
447 
448 #ifdef INCLUDE_CONFIG_FILE
449 /* Actual kernel configuration options. */
450 extern char kernconfstring[];
451 
452 SYSCTL_STRING(_kern, OID_AUTO, conftxt, CTLFLAG_RD | CTLFLAG_MPSAFE,
453     kernconfstring, 0, "Kernel configuration file");
454 #endif
455 
456 static int
457 sysctl_hostid(SYSCTL_HANDLER_ARGS)
458 {
459 	struct prison *pr, *cpr;
460 	u_long tmpid;
461 	int descend, error;
462 
463 	/*
464 	 * Like sysctl_hostname, except it operates on a u_long
465 	 * instead of a string, and is used only for hostid.
466 	 */
467 	pr = req->td->td_ucred->cr_prison;
468 	mtx_lock(&pr->pr_mtx);
469 	tmpid = pr->pr_hostid;
470 	mtx_unlock(&pr->pr_mtx);
471 
472 	error = sysctl_handle_long(oidp, &tmpid, 0, req);
473 	if (error != 0 || req->newptr == NULL)
474 		return (error);
475 
476 	sx_slock(&allprison_lock);
477 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME))
478 		error = EPERM;
479 	else {
480 		while (!(pr->pr_flags & PR_HOST))
481 			pr = pr->pr_parent;
482 		mtx_lock(&pr->pr_mtx);
483 		pr->pr_hostid = tmpid;
484 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
485 			if (cpr->pr_flags & PR_HOST)
486 				descend = 0;
487 			else
488 				cpr->pr_hostid = tmpid;
489 		mtx_unlock(&pr->pr_mtx);
490 	}
491 	sx_sunlock(&allprison_lock);
492 	return (error);
493 }
494 
495 SYSCTL_PROC(_kern, KERN_HOSTID, hostid,
496     CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
497     NULL, 0, sysctl_hostid, "LU", "Host ID");
498 
499 static struct mtx bootid_lk;
500 MTX_SYSINIT(bootid_lock, &bootid_lk, "bootid generator lock", MTX_DEF);
501 
502 static int
503 sysctl_bootid(SYSCTL_HANDLER_ARGS)
504 {
505 	static uint8_t boot_id[16];
506 	static bool initialized = false;
507 
508 	mtx_lock(&bootid_lk);
509 	if (!initialized) {
510 		if (!is_random_seeded()) {
511 			mtx_unlock(&bootid_lk);
512 			return (ENXIO);
513 		}
514 		arc4random_buf(boot_id, sizeof(boot_id));
515 		initialized = true;
516 	}
517 	mtx_unlock(&bootid_lk);
518 
519 	return (SYSCTL_OUT(req, boot_id, sizeof(boot_id)));
520 }
521 SYSCTL_PROC(_kern, OID_AUTO, boot_id,
522     CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
523     NULL, 0, sysctl_bootid, "", "Random boot ID");
524 
525 /*
526  * The osrelease string is copied from the global (osrelease in vers.c) into
527  * prison0 by a sysinit and is inherited by child jails if not changed at jail
528  * creation, so we always return the copy from the current prison data.
529  */
530 static int
531 sysctl_osrelease(SYSCTL_HANDLER_ARGS)
532 {
533 	struct prison *pr;
534 
535 	pr = req->td->td_ucred->cr_prison;
536 	return (SYSCTL_OUT(req, pr->pr_osrelease, strlen(pr->pr_osrelease) + 1));
537 
538 }
539 
540 SYSCTL_PROC(_kern, KERN_OSRELEASE, osrelease,
541     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
542     NULL, 0, sysctl_osrelease, "A", "Operating system release");
543 
544 /*
545  * The osreldate number is copied from the global (osreldate in vers.c) into
546  * prison0 by a sysinit and is inherited by child jails if not changed at jail
547  * creation, so we always return the value from the current prison data.
548  */
549 static int
550 sysctl_osreldate(SYSCTL_HANDLER_ARGS)
551 {
552 	struct prison *pr;
553 
554 	pr = req->td->td_ucred->cr_prison;
555 	return (SYSCTL_OUT(req, &pr->pr_osreldate, sizeof(pr->pr_osreldate)));
556 
557 }
558 
559 /*
560  * NOTICE: The *userland* release date is available in
561  * /usr/include/osreldate.h
562  */
563 SYSCTL_PROC(_kern, KERN_OSRELDATE, osreldate,
564     CTLTYPE_INT | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
565     NULL, 0, sysctl_osreldate, "I", "Kernel release date");
566 
567 /*
568  * The build-id is copied from the ELF section .note.gnu.build-id.  The linker
569  * script defines two variables to expose the beginning and end.  LLVM
570  * currently uses a SHA-1 hash, but other formats can be supported by checking
571  * the length of the section.
572  */
573 
574 extern char __build_id_start[];
575 extern char __build_id_end[];
576 
577 #define	BUILD_ID_HEADER_LEN	0x10
578 #define	BUILD_ID_HASH_MAXLEN	0x14
579 
580 static int
581 sysctl_build_id(SYSCTL_HANDLER_ARGS)
582 {
583 	uintptr_t sectionlen = (uintptr_t)(__build_id_end - __build_id_start);
584 	int hashlen;
585 	char buf[2*BUILD_ID_HASH_MAXLEN+1];
586 
587 	/*
588 	 * The ELF note section has a four byte length for the vendor name,
589 	 * four byte length for the value, and a four byte vendor specific
590 	 * type.  The name for the build id is "GNU\0".  We skip the first 16
591 	 * bytes to read the build hash.  We will return the remaining bytes up
592 	 * to 20 (SHA-1) hash size.  If the hash happens to be a custom number
593 	 * of bytes we will pad the value with zeros, as the section should be
594 	 * four byte aligned.
595 	 */
596 	if (sectionlen <= BUILD_ID_HEADER_LEN ||
597 	    sectionlen > (BUILD_ID_HEADER_LEN + BUILD_ID_HASH_MAXLEN)) {
598 		return (ENOENT);
599 	}
600 
601 	hashlen = sectionlen - BUILD_ID_HEADER_LEN;
602 	for (int i = 0; i < hashlen; i++) {
603 		uint8_t c = __build_id_start[i+BUILD_ID_HEADER_LEN];
604 		snprintf(&buf[2*i], 3, "%02x", c);
605 	}
606 
607 	return (SYSCTL_OUT(req, buf, strlen(buf) + 1));
608 }
609 
610 SYSCTL_PROC(_kern, OID_AUTO, build_id,
611     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
612     NULL, 0, sysctl_build_id, "A", "Operating system build-id");
613 
614 SYSCTL_NODE(_kern, OID_AUTO, features, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
615     "Kernel Features");
616 
617 #ifdef COMPAT_FREEBSD4
618 FEATURE(compat_freebsd4, "Compatible with FreeBSD 4");
619 #endif
620 
621 #ifdef COMPAT_FREEBSD5
622 FEATURE(compat_freebsd5, "Compatible with FreeBSD 5");
623 #endif
624 
625 #ifdef COMPAT_FREEBSD6
626 FEATURE(compat_freebsd6, "Compatible with FreeBSD 6");
627 #endif
628 
629 #ifdef COMPAT_FREEBSD7
630 FEATURE(compat_freebsd7, "Compatible with FreeBSD 7");
631 #endif
632 
633 /*
634  * This is really cheating.  These actually live in the libc, something
635  * which I'm not quite sure is a good idea anyway, but in order for
636  * getnext and friends to actually work, we define dummies here.
637  *
638  * XXXRW: These probably should be CTLFLAG_CAPRD.
639  */
640 SYSCTL_STRING(_user, USER_CS_PATH, cs_path, CTLFLAG_RD,
641     "", 0, "PATH that finds all the standard utilities");
642 SYSCTL_INT(_user, USER_BC_BASE_MAX, bc_base_max, CTLFLAG_RD,
643     SYSCTL_NULL_INT_PTR, 0, "Max ibase/obase values in bc(1)");
644 SYSCTL_INT(_user, USER_BC_DIM_MAX, bc_dim_max, CTLFLAG_RD,
645     SYSCTL_NULL_INT_PTR, 0, "Max array size in bc(1)");
646 SYSCTL_INT(_user, USER_BC_SCALE_MAX, bc_scale_max, CTLFLAG_RD,
647     SYSCTL_NULL_INT_PTR, 0, "Max scale value in bc(1)");
648 SYSCTL_INT(_user, USER_BC_STRING_MAX, bc_string_max, CTLFLAG_RD,
649     SYSCTL_NULL_INT_PTR, 0, "Max string length in bc(1)");
650 SYSCTL_INT(_user, USER_COLL_WEIGHTS_MAX, coll_weights_max, CTLFLAG_RD,
651     SYSCTL_NULL_INT_PTR, 0, "Maximum number of weights assigned to an LC_COLLATE locale entry");
652 SYSCTL_INT(_user, USER_EXPR_NEST_MAX, expr_nest_max, CTLFLAG_RD,
653     SYSCTL_NULL_INT_PTR, 0, "");
654 SYSCTL_INT(_user, USER_LINE_MAX, line_max, CTLFLAG_RD,
655     SYSCTL_NULL_INT_PTR, 0, "Max length (bytes) of a text-processing utility's input line");
656 SYSCTL_INT(_user, USER_RE_DUP_MAX, re_dup_max, CTLFLAG_RD,
657     SYSCTL_NULL_INT_PTR, 0, "Maximum number of repeats of a regexp permitted");
658 SYSCTL_INT(_user, USER_POSIX2_VERSION, posix2_version, CTLFLAG_RD,
659     SYSCTL_NULL_INT_PTR, 0,
660     "The version of POSIX 1003.2 with which the system attempts to comply");
661 SYSCTL_INT(_user, USER_POSIX2_C_BIND, posix2_c_bind, CTLFLAG_RD,
662     SYSCTL_NULL_INT_PTR, 0, "Whether C development supports the C bindings option");
663 SYSCTL_INT(_user, USER_POSIX2_C_DEV, posix2_c_dev, CTLFLAG_RD,
664     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the C development utilities option");
665 SYSCTL_INT(_user, USER_POSIX2_CHAR_TERM, posix2_char_term, CTLFLAG_RD,
666     SYSCTL_NULL_INT_PTR, 0, "");
667 SYSCTL_INT(_user, USER_POSIX2_FORT_DEV, posix2_fort_dev, CTLFLAG_RD,
668     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN development utilities");
669 SYSCTL_INT(_user, USER_POSIX2_FORT_RUN, posix2_fort_run, CTLFLAG_RD,
670     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN runtime utilities");
671 SYSCTL_INT(_user, USER_POSIX2_LOCALEDEF, posix2_localedef, CTLFLAG_RD,
672     SYSCTL_NULL_INT_PTR, 0, "Whether system supports creation of locales");
673 SYSCTL_INT(_user, USER_POSIX2_SW_DEV, posix2_sw_dev, CTLFLAG_RD,
674     SYSCTL_NULL_INT_PTR, 0, "Whether system supports software development utilities");
675 SYSCTL_INT(_user, USER_POSIX2_UPE, posix2_upe, CTLFLAG_RD,
676     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the user portability utilities");
677 SYSCTL_INT(_user, USER_STREAM_MAX, stream_max, CTLFLAG_RD,
678     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of streams a process may have open at one time");
679 SYSCTL_INT(_user, USER_TZNAME_MAX, tzname_max, CTLFLAG_RD,
680     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of types supported for timezone names");
681 
682 static char localbase[MAXPATHLEN] = "";
683 
684 SYSCTL_STRING(_user, USER_LOCALBASE, localbase, CTLFLAG_RWTUN,
685     localbase, sizeof(localbase), "Prefix used to install and locate add-on packages");
686 
687 #include <sys/vnode.h>
688 SYSCTL_INT(_debug_sizeof, OID_AUTO, vnode, CTLFLAG_RD,
689     SYSCTL_NULL_INT_PTR, sizeof(struct vnode), "sizeof(struct vnode)");
690 
691 SYSCTL_INT(_debug_sizeof, OID_AUTO, proc, CTLFLAG_RD,
692     SYSCTL_NULL_INT_PTR, sizeof(struct proc), "sizeof(struct proc)");
693 
694 static int
695 sysctl_kern_pid_max(SYSCTL_HANDLER_ARGS)
696 {
697 	int error, pm;
698 
699 	pm = pid_max;
700 	error = sysctl_handle_int(oidp, &pm, 0, req);
701 	if (error || !req->newptr)
702 		return (error);
703 	sx_xlock(&proctree_lock);
704 	sx_xlock(&allproc_lock);
705 
706 	/*
707 	 * Only permit the values less then PID_MAX.
708 	 * As a safety measure, do not allow to limit the pid_max too much.
709 	 */
710 	if (pm < 300 || pm > PID_MAX)
711 		error = EINVAL;
712 	else
713 		pid_max = pm;
714 	sx_xunlock(&allproc_lock);
715 	sx_xunlock(&proctree_lock);
716 	return (error);
717 }
718 SYSCTL_PROC(_kern, OID_AUTO, pid_max, CTLTYPE_INT |
719     CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
720     0, 0, sysctl_kern_pid_max, "I", "Maximum allowed pid");
721 
722 #include <sys/bio.h>
723 #include <sys/buf.h>
724 SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
725     SYSCTL_NULL_INT_PTR, sizeof(struct bio), "sizeof(struct bio)");
726 SYSCTL_INT(_debug_sizeof, OID_AUTO, buf, CTLFLAG_RD,
727     SYSCTL_NULL_INT_PTR, sizeof(struct buf), "sizeof(struct buf)");
728 
729 #include <sys/user.h>
730 SYSCTL_INT(_debug_sizeof, OID_AUTO, kinfo_proc, CTLFLAG_RD,
731     SYSCTL_NULL_INT_PTR, sizeof(struct kinfo_proc), "sizeof(struct kinfo_proc)");
732 
733 /* Used by kernel debuggers. */
734 const int pcb_size = sizeof(struct pcb);
735 SYSCTL_INT(_debug_sizeof, OID_AUTO, pcb, CTLFLAG_RD,
736     SYSCTL_NULL_INT_PTR, sizeof(struct pcb), "sizeof(struct pcb)");
737 
738 /* XXX compatibility, remove for 6.0 */
739 #include <sys/imgact.h>
740 #include <sys/imgact_elf.h>
741 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
742     &__elfN(fallback_brand), sizeof(__elfN(fallback_brand)),
743     "compatibility for kern.fallback_elf_brand");
744