xref: /freebsd/sys/kern/kern_mib.c (revision cd8537910406e68d4719136a5b0cf6d23bb1b23b)
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 __FBSDID("$FreeBSD$");
42 
43 #include "opt_posix.h"
44 #include "opt_config.h"
45 
46 #include <sys/param.h>
47 #include <sys/boot.h>
48 #include <sys/elf.h>
49 #include <sys/jail.h>
50 #include <sys/kernel.h>
51 #include <sys/limits.h>
52 #include <sys/lock.h>
53 #include <sys/mutex.h>
54 #include <sys/proc.h>
55 #include <sys/random.h>
56 #include <sys/sbuf.h>
57 #include <sys/smp.h>
58 #include <sys/sx.h>
59 #include <sys/sysent.h>
60 #include <sys/vmmeter.h>
61 #include <sys/sysctl.h>
62 #include <sys/systm.h>
63 #include <sys/unistd.h>
64 
65 SYSCTL_ROOT_NODE(0, sysctl, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
66     "Sysctl internal magic");
67 SYSCTL_ROOT_NODE(CTL_KERN, kern, CTLFLAG_RW | CTLFLAG_CAPRD | CTLFLAG_MPSAFE, 0,
68     "High kernel, proc, limits &c");
69 SYSCTL_ROOT_NODE(CTL_VM, vm, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
70     "Virtual memory");
71 SYSCTL_ROOT_NODE(CTL_VFS, vfs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
72     "File system");
73 SYSCTL_ROOT_NODE(CTL_NET, net, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
74     "Network, (see socket.h)");
75 SYSCTL_ROOT_NODE(CTL_DEBUG, debug, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
76     "Debugging");
77 SYSCTL_NODE(_debug, OID_AUTO,  sizeof,  CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
78     "Sizeof various things");
79 SYSCTL_ROOT_NODE(CTL_HW, hw, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
80     "hardware");
81 SYSCTL_ROOT_NODE(CTL_MACHDEP, machdep, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
82     "machine dependent");
83 SYSCTL_NODE(_machdep, OID_AUTO, mitigations, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
84     "Machine dependent platform mitigations.");
85 SYSCTL_ROOT_NODE(CTL_USER, user, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
86     "user-level");
87 SYSCTL_ROOT_NODE(CTL_P1003_1B, p1003_1b, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
88     "p1003_1b, (see p1003_1b.h)");
89 
90 SYSCTL_ROOT_NODE(OID_AUTO, compat, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
91     "Compatibility code");
92 SYSCTL_ROOT_NODE(OID_AUTO, security, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
93     "Security");
94 #ifdef REGRESSION
95 SYSCTL_ROOT_NODE(OID_AUTO, regression, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
96     "Regression test MIB");
97 #endif
98 
99 SYSCTL_STRING(_kern, OID_AUTO, ident, CTLFLAG_RD|CTLFLAG_MPSAFE,
100     kern_ident, 0, "Kernel identifier");
101 
102 SYSCTL_INT(_kern, KERN_OSREV, osrevision, CTLFLAG_RD|CTLFLAG_CAPRD,
103     SYSCTL_NULL_INT_PTR, BSD, "Operating system revision");
104 
105 SYSCTL_STRING(_kern, KERN_VERSION, version, CTLFLAG_RD|CTLFLAG_MPSAFE,
106     version, 0, "Kernel version");
107 
108 SYSCTL_STRING(_kern, OID_AUTO, compiler_version, CTLFLAG_RD|CTLFLAG_MPSAFE,
109     compiler_version, 0, "Version of compiler used to compile kernel");
110 
111 SYSCTL_STRING(_kern, KERN_OSTYPE, ostype, CTLFLAG_RD|CTLFLAG_MPSAFE|
112     CTLFLAG_CAPRD, ostype, 0, "Operating system type");
113 
114 SYSCTL_INT(_kern, KERN_MAXPROC, maxproc, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
115     &maxproc, 0, "Maximum number of processes");
116 
117 SYSCTL_INT(_kern, KERN_MAXPROCPERUID, maxprocperuid, CTLFLAG_RW,
118     &maxprocperuid, 0, "Maximum processes allowed per userid");
119 
120 SYSCTL_INT(_kern, OID_AUTO, maxusers, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
121     &maxusers, 0, "Hint for kernel tuning");
122 
123 SYSCTL_INT(_kern, KERN_ARGMAX, argmax, CTLFLAG_RD|CTLFLAG_CAPRD,
124     SYSCTL_NULL_INT_PTR, ARG_MAX, "Maximum bytes of argument to execve(2)");
125 
126 SYSCTL_INT(_kern, KERN_POSIX1, posix1version, CTLFLAG_RD|CTLFLAG_CAPRD,
127     SYSCTL_NULL_INT_PTR, _POSIX_VERSION, "Version of POSIX attempting to comply to");
128 
129 SYSCTL_INT(_kern, KERN_NGROUPS, ngroups, CTLFLAG_RDTUN |
130     CTLFLAG_NOFETCH | CTLFLAG_CAPRD, &ngroups_max, 0,
131     "Maximum number of supplemental groups a user can belong to");
132 
133 SYSCTL_INT(_kern, KERN_JOB_CONTROL, job_control, CTLFLAG_RD|CTLFLAG_CAPRD,
134     SYSCTL_NULL_INT_PTR, 1, "Whether job control is available");
135 
136 #ifdef _POSIX_SAVED_IDS
137 SYSCTL_INT(_kern, KERN_SAVED_IDS, saved_ids, CTLFLAG_RD|CTLFLAG_CAPRD,
138     SYSCTL_NULL_INT_PTR, 1, "Whether saved set-group/user ID is available");
139 #else
140 SYSCTL_INT(_kern, KERN_SAVED_IDS, saved_ids, CTLFLAG_RD|CTLFLAG_CAPRD,
141     SYSCTL_NULL_INT_PTR, 0, "Whether saved set-group/user ID is available");
142 #endif
143 
144 char kernelname[MAXPATHLEN] = PATH_KERNEL;	/* XXX bloat */
145 
146 SYSCTL_STRING(_kern, KERN_BOOTFILE, bootfile, CTLFLAG_RW | CTLFLAG_MPSAFE,
147     kernelname, sizeof kernelname, "Name of kernel file booted");
148 
149 #ifdef COMPAT_FREEBSD12
150 static int
151 sysctl_maxphys(SYSCTL_HANDLER_ARGS)
152 {
153 	u_long lvalue;
154 	int ivalue;
155 
156 	lvalue = maxphys;
157 	if (sizeof(int) == sizeof(u_long) || req->oldlen >= sizeof(u_long))
158 		return (sysctl_handle_long(oidp, &lvalue, 0, req));
159 	if (lvalue > INT_MAX)
160 		return (sysctl_handle_long(oidp, &lvalue, 0, req));
161 	ivalue = lvalue;
162 	return (sysctl_handle_int(oidp, &ivalue, 0, req));
163 }
164 SYSCTL_PROC(_kern, KERN_MAXPHYS, maxphys, CTLTYPE_LONG | CTLFLAG_RDTUN |
165     CTLFLAG_NOFETCH | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
166     NULL, 0, sysctl_maxphys, "UL", "Maximum block I/O access size");
167 #else
168 SYSCTL_ULONG(_kern, KERN_MAXPHYS, maxphys,
169     CTLFLAG_RDTUN | CTLFLAG_NOFETCH | CTLFLAG_CAPRD,
170     &maxphys, 0, "Maximum block I/O access size");
171 #endif
172 
173 SYSCTL_INT(_hw, HW_NCPU, ncpu, CTLFLAG_RD|CTLFLAG_CAPRD,
174     &mp_ncpus, 0, "Number of active CPUs");
175 
176 SYSCTL_INT(_hw, HW_BYTEORDER, byteorder, CTLFLAG_RD|CTLFLAG_CAPRD,
177     SYSCTL_NULL_INT_PTR, BYTE_ORDER, "System byte order");
178 
179 SYSCTL_INT(_hw, HW_PAGESIZE, pagesize, CTLFLAG_RD|CTLFLAG_CAPRD,
180     SYSCTL_NULL_INT_PTR, PAGE_SIZE, "System memory page size");
181 
182 static int
183 sysctl_kern_arnd(SYSCTL_HANDLER_ARGS)
184 {
185 	char buf[256];
186 	size_t len;
187 
188 	len = MIN(req->oldlen, sizeof(buf));
189 	read_random(buf, len);
190 	return (SYSCTL_OUT(req, buf, len));
191 }
192 
193 SYSCTL_PROC(_kern, KERN_ARND, arandom,
194     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD, NULL, 0,
195     sysctl_kern_arnd, "", "arc4rand");
196 
197 static int
198 sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
199 {
200 	u_long val, p;
201 
202 	p = SIZE_T_MAX >> PAGE_SHIFT;
203 	if (physmem < p)
204 		p = physmem;
205 	val = ctob(p);
206 	return (sysctl_handle_long(oidp, &val, 0, req));
207 }
208 SYSCTL_PROC(_hw, HW_PHYSMEM, physmem,
209     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
210     sysctl_hw_physmem, "LU",
211     "Amount of physical memory (in bytes)");
212 
213 static int
214 sysctl_hw_realmem(SYSCTL_HANDLER_ARGS)
215 {
216 	u_long val, p;
217 
218 	p = SIZE_T_MAX >> PAGE_SHIFT;
219 	if (realmem < p)
220 		p = realmem;
221 	val = ctob(p);
222 	return (sysctl_handle_long(oidp, &val, 0, req));
223 }
224 SYSCTL_PROC(_hw, HW_REALMEM, realmem,
225     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
226     sysctl_hw_realmem, "LU",
227     "Amount of memory (in bytes) reported by the firmware");
228 
229 static int
230 sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
231 {
232 	u_long val, p, p1;
233 
234 	p1 = physmem - vm_wire_count();
235 	p = SIZE_T_MAX >> PAGE_SHIFT;
236 	if (p1 < p)
237 		p = p1;
238 	val = ctob(p);
239 	return (sysctl_handle_long(oidp, &val, 0, req));
240 }
241 SYSCTL_PROC(_hw, HW_USERMEM, usermem,
242     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
243     sysctl_hw_usermem, "LU",
244     "Amount of memory (in bytes) which is not wired");
245 
246 SYSCTL_LONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &physmem, 0,
247     "Amount of physical memory (in pages)");
248 
249 u_long pagesizes[MAXPAGESIZES] = { PAGE_SIZE };
250 
251 static int
252 sysctl_hw_pagesizes(SYSCTL_HANDLER_ARGS)
253 {
254 	int error;
255 	size_t len;
256 #ifdef SCTL_MASK32
257 	int i;
258 	uint32_t pagesizes32[MAXPAGESIZES];
259 
260 	if (req->flags & SCTL_MASK32) {
261 		/*
262 		 * Recreate the "pagesizes" array with 32-bit elements.
263 		 * Truncate any page size greater than UINT32_MAX to zero,
264 		 * which assumes that page sizes are powers of two.
265 		 */
266 		for (i = 0; i < MAXPAGESIZES; i++)
267 			pagesizes32[i] = (uint32_t)pagesizes[i];
268 
269 		len = sizeof(pagesizes32);
270 		if (len > req->oldlen && req->oldptr != NULL)
271 			len = req->oldlen;
272 		error = SYSCTL_OUT(req, pagesizes32, len);
273 	} else
274 #endif
275 	{
276 		len = sizeof(pagesizes);
277 		if (len > req->oldlen && req->oldptr != NULL)
278 			len = req->oldlen;
279 		error = SYSCTL_OUT(req, pagesizes, len);
280 	}
281 	return (error);
282 }
283 SYSCTL_PROC(_hw, OID_AUTO, pagesizes,
284     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
285     sysctl_hw_pagesizes, "S,pagesizes",
286     "Supported page sizes");
287 
288 int adaptive_machine_arch = 1;
289 SYSCTL_INT(_debug, OID_AUTO, adaptive_machine_arch, CTLFLAG_RW,
290     &adaptive_machine_arch, 1,
291     "Adapt reported machine architecture to the ABI of the binary");
292 
293 static const char *
294 proc_machine_arch(struct proc *p)
295 {
296 
297 	if (p->p_sysent->sv_machine_arch != NULL)
298 		return (p->p_sysent->sv_machine_arch(p));
299 #ifdef COMPAT_FREEBSD32
300 	if (SV_PROC_FLAG(p, SV_ILP32))
301 		return (MACHINE_ARCH32);
302 #endif
303 	return (MACHINE_ARCH);
304 }
305 
306 static int
307 sysctl_hw_machine_arch(SYSCTL_HANDLER_ARGS)
308 {
309 	const char *machine_arch;
310 
311 	if (adaptive_machine_arch)
312 		machine_arch = proc_machine_arch(curproc);
313 	else
314 		machine_arch = MACHINE_ARCH;
315 	return (SYSCTL_OUT(req, machine_arch, strlen(machine_arch) + 1));
316 }
317 SYSCTL_PROC(_hw, HW_MACHINE_ARCH, machine_arch, CTLTYPE_STRING | CTLFLAG_RD |
318     CTLFLAG_MPSAFE, NULL, 0, sysctl_hw_machine_arch, "A",
319     "System architecture");
320 
321 #ifndef MACHINE_ARCHES
322 #ifdef COMPAT_FREEBSD32
323 #define	MACHINE_ARCHES	MACHINE_ARCH " " MACHINE_ARCH32
324 #else
325 #define	MACHINE_ARCHES	MACHINE_ARCH
326 #endif
327 #endif
328 
329 SYSCTL_STRING(_kern, OID_AUTO, supported_archs, CTLFLAG_RD | CTLFLAG_MPSAFE,
330     MACHINE_ARCHES, 0, "Supported architectures for binaries");
331 
332 static int
333 sysctl_hostname(SYSCTL_HANDLER_ARGS)
334 {
335 	struct prison *pr, *cpr;
336 	size_t pr_offset;
337 	char tmpname[MAXHOSTNAMELEN];
338 	int descend, error, len;
339 
340 	/*
341 	 * This function can set: hostname domainname hostuuid.
342 	 * Keep that in mind when comments say "hostname".
343 	 */
344 	pr_offset = (size_t)arg1;
345 	len = arg2;
346 	KASSERT(len <= sizeof(tmpname),
347 	    ("length %d too long for %s", len, __func__));
348 
349 	pr = req->td->td_ucred->cr_prison;
350 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME) && req->newptr)
351 		return (EPERM);
352 	/*
353 	 * Make a local copy of hostname to get/set so we don't have to hold
354 	 * the jail mutex during the sysctl copyin/copyout activities.
355 	 */
356 	mtx_lock(&pr->pr_mtx);
357 	bcopy((char *)pr + pr_offset, tmpname, len);
358 	mtx_unlock(&pr->pr_mtx);
359 
360 	error = sysctl_handle_string(oidp, tmpname, len, req);
361 
362 	if (req->newptr != NULL && error == 0) {
363 		/*
364 		 * Copy the locally set hostname to all jails that share
365 		 * this host info.
366 		 */
367 		sx_slock(&allprison_lock);
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 		sx_sunlock(&allprison_lock);
379 	}
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 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME) && req->newptr)
469 		return (EPERM);
470 	tmpid = pr->pr_hostid;
471 	error = sysctl_handle_long(oidp, &tmpid, 0, req);
472 
473 	if (req->newptr != NULL && error == 0) {
474 		sx_slock(&allprison_lock);
475 		while (!(pr->pr_flags & PR_HOST))
476 			pr = pr->pr_parent;
477 		mtx_lock(&pr->pr_mtx);
478 		pr->pr_hostid = tmpid;
479 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
480 			if (cpr->pr_flags & PR_HOST)
481 				descend = 0;
482 			else
483 				cpr->pr_hostid = tmpid;
484 		mtx_unlock(&pr->pr_mtx);
485 		sx_sunlock(&allprison_lock);
486 	}
487 	return (error);
488 }
489 
490 SYSCTL_PROC(_kern, KERN_HOSTID, hostid,
491     CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
492     NULL, 0, sysctl_hostid, "LU", "Host ID");
493 
494 static struct mtx bootid_lk;
495 MTX_SYSINIT(bootid_lock, &bootid_lk, "bootid generator lock", MTX_DEF);
496 
497 static int
498 sysctl_bootid(SYSCTL_HANDLER_ARGS)
499 {
500 	static uint8_t boot_id[16];
501 	static bool initialized = false;
502 
503 	mtx_lock(&bootid_lk);
504 	if (!initialized) {
505 		if (!is_random_seeded()) {
506 			mtx_unlock(&bootid_lk);
507 			return (ENXIO);
508 		}
509 		arc4random_buf(boot_id, sizeof(boot_id));
510 		initialized = true;
511 	}
512 	mtx_unlock(&bootid_lk);
513 
514 	return (SYSCTL_OUT(req, boot_id, sizeof(boot_id)));
515 }
516 SYSCTL_PROC(_kern, OID_AUTO, boot_id,
517     CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
518     NULL, 0, sysctl_bootid, "", "Random boot ID");
519 
520 /*
521  * The osrelease string is copied from the global (osrelease in vers.c) into
522  * prison0 by a sysinit and is inherited by child jails if not changed at jail
523  * creation, so we always return the copy from the current prison data.
524  */
525 static int
526 sysctl_osrelease(SYSCTL_HANDLER_ARGS)
527 {
528 	struct prison *pr;
529 
530 	pr = req->td->td_ucred->cr_prison;
531 	return (SYSCTL_OUT(req, pr->pr_osrelease, strlen(pr->pr_osrelease) + 1));
532 
533 }
534 
535 SYSCTL_PROC(_kern, KERN_OSRELEASE, osrelease,
536     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
537     NULL, 0, sysctl_osrelease, "A", "Operating system release");
538 
539 /*
540  * The osreldate number is copied from the global (osreldate in vers.c) into
541  * prison0 by a sysinit and is inherited by child jails if not changed at jail
542  * creation, so we always return the value from the current prison data.
543  */
544 static int
545 sysctl_osreldate(SYSCTL_HANDLER_ARGS)
546 {
547 	struct prison *pr;
548 
549 	pr = req->td->td_ucred->cr_prison;
550 	return (SYSCTL_OUT(req, &pr->pr_osreldate, sizeof(pr->pr_osreldate)));
551 
552 }
553 
554 /*
555  * NOTICE: The *userland* release date is available in
556  * /usr/include/osreldate.h
557  */
558 SYSCTL_PROC(_kern, KERN_OSRELDATE, osreldate,
559     CTLTYPE_INT | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
560     NULL, 0, sysctl_osreldate, "I", "Kernel release date");
561 
562 /*
563  * The build-id is copied from the ELF section .note.gnu.build-id.  The linker
564  * script defines two variables to expose the beginning and end.  LLVM
565  * currently uses a SHA-1 hash, but other formats can be supported by checking
566  * the length of the section.
567  */
568 
569 extern char __build_id_start[];
570 extern char __build_id_end[];
571 
572 #define	BUILD_ID_HEADER_LEN	0x10
573 #define	BUILD_ID_HASH_MAXLEN	0x14
574 
575 static int
576 sysctl_build_id(SYSCTL_HANDLER_ARGS)
577 {
578 	uintptr_t sectionlen = (uintptr_t)(__build_id_end - __build_id_start);
579 	int hashlen;
580 	char buf[2*BUILD_ID_HASH_MAXLEN+1];
581 
582 	/*
583 	 * The ELF note section has a four byte length for the vendor name,
584 	 * four byte length for the value, and a four byte vendor specific
585 	 * type.  The name for the build id is "GNU\0".  We skip the first 16
586 	 * bytes to read the build hash.  We will return the remaining bytes up
587 	 * to 20 (SHA-1) hash size.  If the hash happens to be a custom number
588 	 * of bytes we will pad the value with zeros, as the section should be
589 	 * four byte aligned.
590 	 */
591 	if (sectionlen <= BUILD_ID_HEADER_LEN ||
592 	    sectionlen > (BUILD_ID_HEADER_LEN + BUILD_ID_HASH_MAXLEN)) {
593 		return (ENOENT);
594 	}
595 
596 	hashlen = sectionlen - BUILD_ID_HEADER_LEN;
597 	for (int i = 0; i < hashlen; i++) {
598 		uint8_t c = __build_id_start[i+BUILD_ID_HEADER_LEN];
599 		snprintf(&buf[2*i], 3, "%02x", c);
600 	}
601 
602 	return (SYSCTL_OUT(req, buf, strlen(buf) + 1));
603 }
604 
605 SYSCTL_PROC(_kern, OID_AUTO, build_id,
606     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
607     NULL, 0, sysctl_build_id, "A", "Operating system build-id");
608 
609 SYSCTL_NODE(_kern, OID_AUTO, features, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
610     "Kernel Features");
611 
612 #ifdef COMPAT_FREEBSD4
613 FEATURE(compat_freebsd4, "Compatible with FreeBSD 4");
614 #endif
615 
616 #ifdef COMPAT_FREEBSD5
617 FEATURE(compat_freebsd5, "Compatible with FreeBSD 5");
618 #endif
619 
620 #ifdef COMPAT_FREEBSD6
621 FEATURE(compat_freebsd6, "Compatible with FreeBSD 6");
622 #endif
623 
624 #ifdef COMPAT_FREEBSD7
625 FEATURE(compat_freebsd7, "Compatible with FreeBSD 7");
626 #endif
627 
628 /*
629  * This is really cheating.  These actually live in the libc, something
630  * which I'm not quite sure is a good idea anyway, but in order for
631  * getnext and friends to actually work, we define dummies here.
632  *
633  * XXXRW: These probably should be CTLFLAG_CAPRD.
634  */
635 SYSCTL_STRING(_user, USER_CS_PATH, cs_path, CTLFLAG_RD,
636     "", 0, "PATH that finds all the standard utilities");
637 SYSCTL_INT(_user, USER_BC_BASE_MAX, bc_base_max, CTLFLAG_RD,
638     SYSCTL_NULL_INT_PTR, 0, "Max ibase/obase values in bc(1)");
639 SYSCTL_INT(_user, USER_BC_DIM_MAX, bc_dim_max, CTLFLAG_RD,
640     SYSCTL_NULL_INT_PTR, 0, "Max array size in bc(1)");
641 SYSCTL_INT(_user, USER_BC_SCALE_MAX, bc_scale_max, CTLFLAG_RD,
642     SYSCTL_NULL_INT_PTR, 0, "Max scale value in bc(1)");
643 SYSCTL_INT(_user, USER_BC_STRING_MAX, bc_string_max, CTLFLAG_RD,
644     SYSCTL_NULL_INT_PTR, 0, "Max string length in bc(1)");
645 SYSCTL_INT(_user, USER_COLL_WEIGHTS_MAX, coll_weights_max, CTLFLAG_RD,
646     SYSCTL_NULL_INT_PTR, 0, "Maximum number of weights assigned to an LC_COLLATE locale entry");
647 SYSCTL_INT(_user, USER_EXPR_NEST_MAX, expr_nest_max, CTLFLAG_RD,
648     SYSCTL_NULL_INT_PTR, 0, "");
649 SYSCTL_INT(_user, USER_LINE_MAX, line_max, CTLFLAG_RD,
650     SYSCTL_NULL_INT_PTR, 0, "Max length (bytes) of a text-processing utility's input line");
651 SYSCTL_INT(_user, USER_RE_DUP_MAX, re_dup_max, CTLFLAG_RD,
652     SYSCTL_NULL_INT_PTR, 0, "Maximum number of repeats of a regexp permitted");
653 SYSCTL_INT(_user, USER_POSIX2_VERSION, posix2_version, CTLFLAG_RD,
654     SYSCTL_NULL_INT_PTR, 0,
655     "The version of POSIX 1003.2 with which the system attempts to comply");
656 SYSCTL_INT(_user, USER_POSIX2_C_BIND, posix2_c_bind, CTLFLAG_RD,
657     SYSCTL_NULL_INT_PTR, 0, "Whether C development supports the C bindings option");
658 SYSCTL_INT(_user, USER_POSIX2_C_DEV, posix2_c_dev, CTLFLAG_RD,
659     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the C development utilities option");
660 SYSCTL_INT(_user, USER_POSIX2_CHAR_TERM, posix2_char_term, CTLFLAG_RD,
661     SYSCTL_NULL_INT_PTR, 0, "");
662 SYSCTL_INT(_user, USER_POSIX2_FORT_DEV, posix2_fort_dev, CTLFLAG_RD,
663     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN development utilities");
664 SYSCTL_INT(_user, USER_POSIX2_FORT_RUN, posix2_fort_run, CTLFLAG_RD,
665     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN runtime utilities");
666 SYSCTL_INT(_user, USER_POSIX2_LOCALEDEF, posix2_localedef, CTLFLAG_RD,
667     SYSCTL_NULL_INT_PTR, 0, "Whether system supports creation of locales");
668 SYSCTL_INT(_user, USER_POSIX2_SW_DEV, posix2_sw_dev, CTLFLAG_RD,
669     SYSCTL_NULL_INT_PTR, 0, "Whether system supports software development utilities");
670 SYSCTL_INT(_user, USER_POSIX2_UPE, posix2_upe, CTLFLAG_RD,
671     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the user portability utilities");
672 SYSCTL_INT(_user, USER_STREAM_MAX, stream_max, CTLFLAG_RD,
673     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of streams a process may have open at one time");
674 SYSCTL_INT(_user, USER_TZNAME_MAX, tzname_max, CTLFLAG_RD,
675     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of types supported for timezone names");
676 
677 static char localbase[MAXPATHLEN] = "";
678 
679 SYSCTL_STRING(_user, USER_LOCALBASE, localbase, CTLFLAG_RWTUN,
680     localbase, sizeof(localbase), "Prefix used to install and locate add-on packages");
681 
682 #include <sys/vnode.h>
683 SYSCTL_INT(_debug_sizeof, OID_AUTO, vnode, CTLFLAG_RD,
684     SYSCTL_NULL_INT_PTR, sizeof(struct vnode), "sizeof(struct vnode)");
685 
686 SYSCTL_INT(_debug_sizeof, OID_AUTO, proc, CTLFLAG_RD,
687     SYSCTL_NULL_INT_PTR, sizeof(struct proc), "sizeof(struct proc)");
688 
689 static int
690 sysctl_kern_pid_max(SYSCTL_HANDLER_ARGS)
691 {
692 	int error, pm;
693 
694 	pm = pid_max;
695 	error = sysctl_handle_int(oidp, &pm, 0, req);
696 	if (error || !req->newptr)
697 		return (error);
698 	sx_xlock(&proctree_lock);
699 	sx_xlock(&allproc_lock);
700 
701 	/*
702 	 * Only permit the values less then PID_MAX.
703 	 * As a safety measure, do not allow to limit the pid_max too much.
704 	 */
705 	if (pm < 300 || pm > PID_MAX)
706 		error = EINVAL;
707 	else
708 		pid_max = pm;
709 	sx_xunlock(&allproc_lock);
710 	sx_xunlock(&proctree_lock);
711 	return (error);
712 }
713 SYSCTL_PROC(_kern, OID_AUTO, pid_max, CTLTYPE_INT |
714     CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
715     0, 0, sysctl_kern_pid_max, "I", "Maximum allowed pid");
716 
717 #include <sys/bio.h>
718 #include <sys/buf.h>
719 SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
720     SYSCTL_NULL_INT_PTR, sizeof(struct bio), "sizeof(struct bio)");
721 SYSCTL_INT(_debug_sizeof, OID_AUTO, buf, CTLFLAG_RD,
722     SYSCTL_NULL_INT_PTR, sizeof(struct buf), "sizeof(struct buf)");
723 
724 #include <sys/user.h>
725 SYSCTL_INT(_debug_sizeof, OID_AUTO, kinfo_proc, CTLFLAG_RD,
726     SYSCTL_NULL_INT_PTR, sizeof(struct kinfo_proc), "sizeof(struct kinfo_proc)");
727 
728 /* Used by kernel debuggers. */
729 const int pcb_size = sizeof(struct pcb);
730 SYSCTL_INT(_debug_sizeof, OID_AUTO, pcb, CTLFLAG_RD,
731     SYSCTL_NULL_INT_PTR, sizeof(struct pcb), "sizeof(struct pcb)");
732 
733 /* XXX compatibility, remove for 6.0 */
734 #include <sys/imgact.h>
735 #include <sys/imgact_elf.h>
736 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
737     &__elfN(fallback_brand), sizeof(__elfN(fallback_brand)),
738     "compatibility for kern.fallback_elf_brand");
739