xref: /freebsd/sys/kern/kern_mib.c (revision e17f5b1d)
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 SYSCTL_INT(_kern, KERN_MAXPHYS, maxphys, CTLFLAG_RD | CTLFLAG_CAPRD,
150     SYSCTL_NULL_INT_PTR, MAXPHYS, "Maximum block I/O access size");
151 
152 SYSCTL_INT(_hw, HW_NCPU, ncpu, CTLFLAG_RD|CTLFLAG_CAPRD,
153     &mp_ncpus, 0, "Number of active CPUs");
154 
155 SYSCTL_INT(_hw, HW_BYTEORDER, byteorder, CTLFLAG_RD|CTLFLAG_CAPRD,
156     SYSCTL_NULL_INT_PTR, BYTE_ORDER, "System byte order");
157 
158 SYSCTL_INT(_hw, HW_PAGESIZE, pagesize, CTLFLAG_RD|CTLFLAG_CAPRD,
159     SYSCTL_NULL_INT_PTR, PAGE_SIZE, "System memory page size");
160 
161 static int
162 sysctl_kern_arnd(SYSCTL_HANDLER_ARGS)
163 {
164 	char buf[256];
165 	size_t len;
166 
167 	len = MIN(req->oldlen, sizeof(buf));
168 	read_random(buf, len);
169 	return (SYSCTL_OUT(req, buf, len));
170 }
171 
172 SYSCTL_PROC(_kern, KERN_ARND, arandom,
173     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD, NULL, 0,
174     sysctl_kern_arnd, "", "arc4rand");
175 
176 static int
177 sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
178 {
179 	u_long val, p;
180 
181 	p = SIZE_T_MAX >> PAGE_SHIFT;
182 	if (physmem < p)
183 		p = physmem;
184 	val = ctob(p);
185 	return (sysctl_handle_long(oidp, &val, 0, req));
186 }
187 SYSCTL_PROC(_hw, HW_PHYSMEM, physmem,
188     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
189     sysctl_hw_physmem, "LU",
190     "Amount of physical memory (in bytes)");
191 
192 static int
193 sysctl_hw_realmem(SYSCTL_HANDLER_ARGS)
194 {
195 	u_long val, p;
196 
197 	p = SIZE_T_MAX >> PAGE_SHIFT;
198 	if (realmem < p)
199 		p = realmem;
200 	val = ctob(p);
201 	return (sysctl_handle_long(oidp, &val, 0, req));
202 }
203 SYSCTL_PROC(_hw, HW_REALMEM, realmem,
204     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
205     sysctl_hw_realmem, "LU",
206     "Amount of memory (in bytes) reported by the firmware");
207 
208 static int
209 sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
210 {
211 	u_long val, p, p1;
212 
213 	p1 = physmem - vm_wire_count();
214 	p = SIZE_T_MAX >> PAGE_SHIFT;
215 	if (p1 < p)
216 		p = p1;
217 	val = ctob(p);
218 	return (sysctl_handle_long(oidp, &val, 0, req));
219 }
220 SYSCTL_PROC(_hw, HW_USERMEM, usermem,
221     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
222     sysctl_hw_usermem, "LU",
223     "Amount of memory (in bytes) which is not wired");
224 
225 SYSCTL_LONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &physmem, 0,
226     "Amount of physical memory (in pages)");
227 
228 u_long pagesizes[MAXPAGESIZES] = { PAGE_SIZE };
229 
230 static int
231 sysctl_hw_pagesizes(SYSCTL_HANDLER_ARGS)
232 {
233 	int error;
234 	size_t len;
235 #ifdef SCTL_MASK32
236 	int i;
237 	uint32_t pagesizes32[MAXPAGESIZES];
238 
239 	if (req->flags & SCTL_MASK32) {
240 		/*
241 		 * Recreate the "pagesizes" array with 32-bit elements.
242 		 * Truncate any page size greater than UINT32_MAX to zero,
243 		 * which assumes that page sizes are powers of two.
244 		 */
245 		for (i = 0; i < MAXPAGESIZES; i++)
246 			pagesizes32[i] = (uint32_t)pagesizes[i];
247 
248 		len = sizeof(pagesizes32);
249 		if (len > req->oldlen)
250 			len = req->oldlen;
251 		error = SYSCTL_OUT(req, pagesizes32, len);
252 	} else
253 #endif
254 	{
255 		len = sizeof(pagesizes);
256 		if (len > req->oldlen)
257 			len = req->oldlen;
258 		error = SYSCTL_OUT(req, pagesizes, len);
259 	}
260 	return (error);
261 }
262 SYSCTL_PROC(_hw, OID_AUTO, pagesizes,
263     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
264     sysctl_hw_pagesizes, "LU",
265     "Supported page sizes");
266 
267 int adaptive_machine_arch = 1;
268 SYSCTL_INT(_debug, OID_AUTO, adaptive_machine_arch, CTLFLAG_RW,
269     &adaptive_machine_arch, 1,
270     "Adapt reported machine architecture to the ABI of the binary");
271 
272 static const char *
273 proc_machine_arch(struct proc *p)
274 {
275 
276 	if (p->p_sysent->sv_machine_arch != NULL)
277 		return (p->p_sysent->sv_machine_arch(p));
278 #ifdef COMPAT_FREEBSD32
279 	if (SV_PROC_FLAG(p, SV_ILP32))
280 		return (MACHINE_ARCH32);
281 #endif
282 	return (MACHINE_ARCH);
283 }
284 
285 static int
286 sysctl_hw_machine_arch(SYSCTL_HANDLER_ARGS)
287 {
288 	const char *machine_arch;
289 
290 	if (adaptive_machine_arch)
291 		machine_arch = proc_machine_arch(curproc);
292 	else
293 		machine_arch = MACHINE_ARCH;
294 	return (SYSCTL_OUT(req, machine_arch, strlen(machine_arch) + 1));
295 }
296 SYSCTL_PROC(_hw, HW_MACHINE_ARCH, machine_arch, CTLTYPE_STRING | CTLFLAG_RD |
297     CTLFLAG_MPSAFE, NULL, 0, sysctl_hw_machine_arch, "A",
298     "System architecture");
299 
300 #ifndef MACHINE_ARCHES
301 #ifdef COMPAT_FREEBSD32
302 #define	MACHINE_ARCHES	MACHINE_ARCH " " MACHINE_ARCH32
303 #else
304 #define	MACHINE_ARCHES	MACHINE_ARCH
305 #endif
306 #endif
307 
308 SYSCTL_STRING(_kern, OID_AUTO, supported_archs, CTLFLAG_RD | CTLFLAG_MPSAFE,
309     MACHINE_ARCHES, 0, "Supported architectures for binaries");
310 
311 static int
312 sysctl_hostname(SYSCTL_HANDLER_ARGS)
313 {
314 	struct prison *pr, *cpr;
315 	size_t pr_offset;
316 	char tmpname[MAXHOSTNAMELEN];
317 	int descend, error, len;
318 
319 	/*
320 	 * This function can set: hostname domainname hostuuid.
321 	 * Keep that in mind when comments say "hostname".
322 	 */
323 	pr_offset = (size_t)arg1;
324 	len = arg2;
325 	KASSERT(len <= sizeof(tmpname),
326 	    ("length %d too long for %s", len, __func__));
327 
328 	pr = req->td->td_ucred->cr_prison;
329 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME) && req->newptr)
330 		return (EPERM);
331 	/*
332 	 * Make a local copy of hostname to get/set so we don't have to hold
333 	 * the jail mutex during the sysctl copyin/copyout activities.
334 	 */
335 	mtx_lock(&pr->pr_mtx);
336 	bcopy((char *)pr + pr_offset, tmpname, len);
337 	mtx_unlock(&pr->pr_mtx);
338 
339 	error = sysctl_handle_string(oidp, tmpname, len, req);
340 
341 	if (req->newptr != NULL && error == 0) {
342 		/*
343 		 * Copy the locally set hostname to all jails that share
344 		 * this host info.
345 		 */
346 		sx_slock(&allprison_lock);
347 		while (!(pr->pr_flags & PR_HOST))
348 			pr = pr->pr_parent;
349 		mtx_lock(&pr->pr_mtx);
350 		bcopy(tmpname, (char *)pr + pr_offset, len);
351 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
352 			if (cpr->pr_flags & PR_HOST)
353 				descend = 0;
354 			else
355 				bcopy(tmpname, (char *)cpr + pr_offset, len);
356 		mtx_unlock(&pr->pr_mtx);
357 		sx_sunlock(&allprison_lock);
358 	}
359 	return (error);
360 }
361 
362 SYSCTL_PROC(_kern, KERN_HOSTNAME, hostname,
363     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
364     (void *)(offsetof(struct prison, pr_hostname)), MAXHOSTNAMELEN,
365     sysctl_hostname, "A", "Hostname");
366 SYSCTL_PROC(_kern, KERN_NISDOMAINNAME, domainname,
367     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
368     (void *)(offsetof(struct prison, pr_domainname)), MAXHOSTNAMELEN,
369     sysctl_hostname, "A", "Name of the current YP/NIS domain");
370 SYSCTL_PROC(_kern, KERN_HOSTUUID, hostuuid,
371     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
372     (void *)(offsetof(struct prison, pr_hostuuid)), HOSTUUIDLEN,
373     sysctl_hostname, "A", "Host UUID");
374 
375 static int	regression_securelevel_nonmonotonic = 0;
376 
377 #ifdef REGRESSION
378 SYSCTL_INT(_regression, OID_AUTO, securelevel_nonmonotonic, CTLFLAG_RW,
379     &regression_securelevel_nonmonotonic, 0, "securelevel may be lowered");
380 #endif
381 
382 static int
383 sysctl_kern_securelvl(SYSCTL_HANDLER_ARGS)
384 {
385 	struct prison *pr, *cpr;
386 	int descend, error, level;
387 
388 	pr = req->td->td_ucred->cr_prison;
389 
390 	/*
391 	 * Reading the securelevel is easy, since the current jail's level
392 	 * is known to be at least as secure as any higher levels.  Perform
393 	 * a lockless read since the securelevel is an integer.
394 	 */
395 	level = pr->pr_securelevel;
396 	error = sysctl_handle_int(oidp, &level, 0, req);
397 	if (error || !req->newptr)
398 		return (error);
399 	/* Permit update only if the new securelevel exceeds the old. */
400 	sx_slock(&allprison_lock);
401 	mtx_lock(&pr->pr_mtx);
402 	if (!regression_securelevel_nonmonotonic &&
403 	    level < pr->pr_securelevel) {
404 		mtx_unlock(&pr->pr_mtx);
405 		sx_sunlock(&allprison_lock);
406 		return (EPERM);
407 	}
408 	pr->pr_securelevel = level;
409 	/*
410 	 * Set all child jails to be at least this level, but do not lower
411 	 * them (even if regression_securelevel_nonmonotonic).
412 	 */
413 	FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend) {
414 		if (cpr->pr_securelevel < level)
415 			cpr->pr_securelevel = level;
416 	}
417 	mtx_unlock(&pr->pr_mtx);
418 	sx_sunlock(&allprison_lock);
419 	return (error);
420 }
421 
422 SYSCTL_PROC(_kern, KERN_SECURELVL, securelevel,
423     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE, 0, 0,
424     sysctl_kern_securelvl, "I",
425     "Current secure level");
426 
427 #ifdef INCLUDE_CONFIG_FILE
428 /* Actual kernel configuration options. */
429 extern char kernconfstring[];
430 
431 SYSCTL_STRING(_kern, OID_AUTO, conftxt, CTLFLAG_RD | CTLFLAG_MPSAFE,
432     kernconfstring, 0, "Kernel configuration file");
433 #endif
434 
435 static int
436 sysctl_hostid(SYSCTL_HANDLER_ARGS)
437 {
438 	struct prison *pr, *cpr;
439 	u_long tmpid;
440 	int descend, error;
441 
442 	/*
443 	 * Like sysctl_hostname, except it operates on a u_long
444 	 * instead of a string, and is used only for hostid.
445 	 */
446 	pr = req->td->td_ucred->cr_prison;
447 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME) && req->newptr)
448 		return (EPERM);
449 	tmpid = pr->pr_hostid;
450 	error = sysctl_handle_long(oidp, &tmpid, 0, req);
451 
452 	if (req->newptr != NULL && error == 0) {
453 		sx_slock(&allprison_lock);
454 		while (!(pr->pr_flags & PR_HOST))
455 			pr = pr->pr_parent;
456 		mtx_lock(&pr->pr_mtx);
457 		pr->pr_hostid = tmpid;
458 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
459 			if (cpr->pr_flags & PR_HOST)
460 				descend = 0;
461 			else
462 				cpr->pr_hostid = tmpid;
463 		mtx_unlock(&pr->pr_mtx);
464 		sx_sunlock(&allprison_lock);
465 	}
466 	return (error);
467 }
468 
469 SYSCTL_PROC(_kern, KERN_HOSTID, hostid,
470     CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
471     NULL, 0, sysctl_hostid, "LU", "Host ID");
472 
473 static struct mtx bootid_lk;
474 MTX_SYSINIT(bootid_lock, &bootid_lk, "bootid generator lock", MTX_DEF);
475 
476 static int
477 sysctl_bootid(SYSCTL_HANDLER_ARGS)
478 {
479 	static uint8_t boot_id[16];
480 	static bool initialized = false;
481 
482 	mtx_lock(&bootid_lk);
483 	if (!initialized) {
484 		if (!is_random_seeded()) {
485 			mtx_unlock(&bootid_lk);
486 			return (ENXIO);
487 		}
488 		arc4random_buf(boot_id, sizeof(boot_id));
489 		initialized = true;
490 	}
491 	mtx_unlock(&bootid_lk);
492 
493 	return (SYSCTL_OUT(req, boot_id, sizeof(boot_id)));
494 }
495 SYSCTL_PROC(_kern, OID_AUTO, boot_id,
496     CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
497     NULL, 0, sysctl_bootid, "", "Random boot ID");
498 
499 /*
500  * The osrelease string is copied from the global (osrelease in vers.c) into
501  * prison0 by a sysinit and is inherited by child jails if not changed at jail
502  * creation, so we always return the copy from the current prison data.
503  */
504 static int
505 sysctl_osrelease(SYSCTL_HANDLER_ARGS)
506 {
507 	struct prison *pr;
508 
509 	pr = req->td->td_ucred->cr_prison;
510 	return (SYSCTL_OUT(req, pr->pr_osrelease, strlen(pr->pr_osrelease) + 1));
511 
512 }
513 
514 SYSCTL_PROC(_kern, KERN_OSRELEASE, osrelease,
515     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
516     NULL, 0, sysctl_osrelease, "A", "Operating system release");
517 
518 /*
519  * The osreldate number is copied from the global (osreldate in vers.c) into
520  * prison0 by a sysinit and is inherited by child jails if not changed at jail
521  * creation, so we always return the value from the current prison data.
522  */
523 static int
524 sysctl_osreldate(SYSCTL_HANDLER_ARGS)
525 {
526 	struct prison *pr;
527 
528 	pr = req->td->td_ucred->cr_prison;
529 	return (SYSCTL_OUT(req, &pr->pr_osreldate, sizeof(pr->pr_osreldate)));
530 
531 }
532 
533 /*
534  * NOTICE: The *userland* release date is available in
535  * /usr/include/osreldate.h
536  */
537 SYSCTL_PROC(_kern, KERN_OSRELDATE, osreldate,
538     CTLTYPE_INT | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
539     NULL, 0, sysctl_osreldate, "I", "Kernel release date");
540 
541 /*
542  * The build-id is copied from the ELF section .note.gnu.build-id.  The linker
543  * script defines two variables to expose the beginning and end.  LLVM
544  * currently uses a SHA-1 hash, but other formats can be supported by checking
545  * the length of the section.
546  */
547 
548 extern char __build_id_start[];
549 extern char __build_id_end[];
550 
551 #define	BUILD_ID_HEADER_LEN	0x10
552 #define	BUILD_ID_HASH_MAXLEN	0x14
553 
554 static int
555 sysctl_build_id(SYSCTL_HANDLER_ARGS)
556 {
557 	uintptr_t sectionlen = (uintptr_t)(__build_id_end - __build_id_start);
558 	int hashlen;
559 	char buf[2*BUILD_ID_HASH_MAXLEN+1];
560 
561 	/*
562 	 * The ELF note section has a four byte length for the vendor name,
563 	 * four byte length for the value, and a four byte vendor specific
564 	 * type.  The name for the build id is "GNU\0".  We skip the first 16
565 	 * bytes to read the build hash.  We will return the remaining bytes up
566 	 * to 20 (SHA-1) hash size.  If the hash happens to be a custom number
567 	 * of bytes we will pad the value with zeros, as the section should be
568 	 * four byte aligned.
569 	 */
570 	if (sectionlen <= BUILD_ID_HEADER_LEN ||
571 	    sectionlen > (BUILD_ID_HEADER_LEN + BUILD_ID_HASH_MAXLEN)) {
572 		return (ENOENT);
573 	}
574 
575 	hashlen = sectionlen - BUILD_ID_HEADER_LEN;
576 	for (int i = 0; i < hashlen; i++) {
577 		uint8_t c = __build_id_start[i+BUILD_ID_HEADER_LEN];
578 		snprintf(&buf[2*i], 3, "%02x", c);
579 	}
580 
581 	return (SYSCTL_OUT(req, buf, strlen(buf) + 1));
582 }
583 
584 SYSCTL_PROC(_kern, OID_AUTO, build_id,
585     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
586     NULL, 0, sysctl_build_id, "A", "Operating system build-id");
587 
588 SYSCTL_NODE(_kern, OID_AUTO, features, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
589     "Kernel Features");
590 
591 #ifdef COMPAT_FREEBSD4
592 FEATURE(compat_freebsd4, "Compatible with FreeBSD 4");
593 #endif
594 
595 #ifdef COMPAT_FREEBSD5
596 FEATURE(compat_freebsd5, "Compatible with FreeBSD 5");
597 #endif
598 
599 #ifdef COMPAT_FREEBSD6
600 FEATURE(compat_freebsd6, "Compatible with FreeBSD 6");
601 #endif
602 
603 #ifdef COMPAT_FREEBSD7
604 FEATURE(compat_freebsd7, "Compatible with FreeBSD 7");
605 #endif
606 
607 /*
608  * This is really cheating.  These actually live in the libc, something
609  * which I'm not quite sure is a good idea anyway, but in order for
610  * getnext and friends to actually work, we define dummies here.
611  *
612  * XXXRW: These probably should be CTLFLAG_CAPRD.
613  */
614 SYSCTL_STRING(_user, USER_CS_PATH, cs_path, CTLFLAG_RD,
615     "", 0, "PATH that finds all the standard utilities");
616 SYSCTL_INT(_user, USER_BC_BASE_MAX, bc_base_max, CTLFLAG_RD,
617     SYSCTL_NULL_INT_PTR, 0, "Max ibase/obase values in bc(1)");
618 SYSCTL_INT(_user, USER_BC_DIM_MAX, bc_dim_max, CTLFLAG_RD,
619     SYSCTL_NULL_INT_PTR, 0, "Max array size in bc(1)");
620 SYSCTL_INT(_user, USER_BC_SCALE_MAX, bc_scale_max, CTLFLAG_RD,
621     SYSCTL_NULL_INT_PTR, 0, "Max scale value in bc(1)");
622 SYSCTL_INT(_user, USER_BC_STRING_MAX, bc_string_max, CTLFLAG_RD,
623     SYSCTL_NULL_INT_PTR, 0, "Max string length in bc(1)");
624 SYSCTL_INT(_user, USER_COLL_WEIGHTS_MAX, coll_weights_max, CTLFLAG_RD,
625     SYSCTL_NULL_INT_PTR, 0, "Maximum number of weights assigned to an LC_COLLATE locale entry");
626 SYSCTL_INT(_user, USER_EXPR_NEST_MAX, expr_nest_max, CTLFLAG_RD,
627     SYSCTL_NULL_INT_PTR, 0, "");
628 SYSCTL_INT(_user, USER_LINE_MAX, line_max, CTLFLAG_RD,
629     SYSCTL_NULL_INT_PTR, 0, "Max length (bytes) of a text-processing utility's input line");
630 SYSCTL_INT(_user, USER_RE_DUP_MAX, re_dup_max, CTLFLAG_RD,
631     SYSCTL_NULL_INT_PTR, 0, "Maximum number of repeats of a regexp permitted");
632 SYSCTL_INT(_user, USER_POSIX2_VERSION, posix2_version, CTLFLAG_RD,
633     SYSCTL_NULL_INT_PTR, 0,
634     "The version of POSIX 1003.2 with which the system attempts to comply");
635 SYSCTL_INT(_user, USER_POSIX2_C_BIND, posix2_c_bind, CTLFLAG_RD,
636     SYSCTL_NULL_INT_PTR, 0, "Whether C development supports the C bindings option");
637 SYSCTL_INT(_user, USER_POSIX2_C_DEV, posix2_c_dev, CTLFLAG_RD,
638     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the C development utilities option");
639 SYSCTL_INT(_user, USER_POSIX2_CHAR_TERM, posix2_char_term, CTLFLAG_RD,
640     SYSCTL_NULL_INT_PTR, 0, "");
641 SYSCTL_INT(_user, USER_POSIX2_FORT_DEV, posix2_fort_dev, CTLFLAG_RD,
642     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN development utilities");
643 SYSCTL_INT(_user, USER_POSIX2_FORT_RUN, posix2_fort_run, CTLFLAG_RD,
644     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN runtime utilities");
645 SYSCTL_INT(_user, USER_POSIX2_LOCALEDEF, posix2_localedef, CTLFLAG_RD,
646     SYSCTL_NULL_INT_PTR, 0, "Whether system supports creation of locales");
647 SYSCTL_INT(_user, USER_POSIX2_SW_DEV, posix2_sw_dev, CTLFLAG_RD,
648     SYSCTL_NULL_INT_PTR, 0, "Whether system supports software development utilities");
649 SYSCTL_INT(_user, USER_POSIX2_UPE, posix2_upe, CTLFLAG_RD,
650     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the user portability utilities");
651 SYSCTL_INT(_user, USER_STREAM_MAX, stream_max, CTLFLAG_RD,
652     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of streams a process may have open at one time");
653 SYSCTL_INT(_user, USER_TZNAME_MAX, tzname_max, CTLFLAG_RD,
654     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of types supported for timezone names");
655 
656 #include <sys/vnode.h>
657 SYSCTL_INT(_debug_sizeof, OID_AUTO, vnode, CTLFLAG_RD,
658     SYSCTL_NULL_INT_PTR, sizeof(struct vnode), "sizeof(struct vnode)");
659 
660 SYSCTL_INT(_debug_sizeof, OID_AUTO, proc, CTLFLAG_RD,
661     SYSCTL_NULL_INT_PTR, sizeof(struct proc), "sizeof(struct proc)");
662 
663 static int
664 sysctl_kern_pid_max(SYSCTL_HANDLER_ARGS)
665 {
666 	int error, pm;
667 
668 	pm = pid_max;
669 	error = sysctl_handle_int(oidp, &pm, 0, req);
670 	if (error || !req->newptr)
671 		return (error);
672 	sx_xlock(&proctree_lock);
673 	sx_xlock(&allproc_lock);
674 
675 	/*
676 	 * Only permit the values less then PID_MAX.
677 	 * As a safety measure, do not allow to limit the pid_max too much.
678 	 */
679 	if (pm < 300 || pm > PID_MAX)
680 		error = EINVAL;
681 	else
682 		pid_max = pm;
683 	sx_xunlock(&allproc_lock);
684 	sx_xunlock(&proctree_lock);
685 	return (error);
686 }
687 SYSCTL_PROC(_kern, OID_AUTO, pid_max, CTLTYPE_INT |
688     CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
689     0, 0, sysctl_kern_pid_max, "I", "Maximum allowed pid");
690 
691 #include <sys/bio.h>
692 #include <sys/buf.h>
693 SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
694     SYSCTL_NULL_INT_PTR, sizeof(struct bio), "sizeof(struct bio)");
695 SYSCTL_INT(_debug_sizeof, OID_AUTO, buf, CTLFLAG_RD,
696     SYSCTL_NULL_INT_PTR, sizeof(struct buf), "sizeof(struct buf)");
697 
698 #include <sys/user.h>
699 SYSCTL_INT(_debug_sizeof, OID_AUTO, kinfo_proc, CTLFLAG_RD,
700     SYSCTL_NULL_INT_PTR, sizeof(struct kinfo_proc), "sizeof(struct kinfo_proc)");
701 
702 /* Used by kernel debuggers. */
703 const int pcb_size = sizeof(struct pcb);
704 SYSCTL_INT(_debug_sizeof, OID_AUTO, pcb, CTLFLAG_RD,
705     SYSCTL_NULL_INT_PTR, sizeof(struct pcb), "sizeof(struct pcb)");
706 
707 /* XXX compatibility, remove for 6.0 */
708 #include <sys/imgact.h>
709 #include <sys/imgact_elf.h>
710 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
711     &__elfN(fallback_brand), sizeof(__elfN(fallback_brand)),
712     "compatibility for kern.fallback_elf_brand");
713