xref: /freebsd/sys/kern/kern_mib.c (revision 134e17798c9af53632b372348ab828e75e65bf46)
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.  Truncate
242 		 * any page size greater than UINT32_MAX to zero.
243 		 */
244 		for (i = 0; i < MAXPAGESIZES; i++)
245 			pagesizes32[i] = (uint32_t)pagesizes[i];
246 
247 		len = sizeof(pagesizes32);
248 		if (len > req->oldlen)
249 			len = req->oldlen;
250 		error = SYSCTL_OUT(req, pagesizes32, len);
251 	} else
252 #endif
253 	{
254 		len = sizeof(pagesizes);
255 		if (len > req->oldlen)
256 			len = req->oldlen;
257 		error = SYSCTL_OUT(req, pagesizes, len);
258 	}
259 	return (error);
260 }
261 SYSCTL_PROC(_hw, OID_AUTO, pagesizes,
262     CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
263     sysctl_hw_pagesizes, "LU",
264     "Supported page sizes");
265 
266 int adaptive_machine_arch = 1;
267 SYSCTL_INT(_debug, OID_AUTO, adaptive_machine_arch, CTLFLAG_RW,
268     &adaptive_machine_arch, 1,
269     "Adapt reported machine architecture to the ABI of the binary");
270 
271 static const char *
272 proc_machine_arch(struct proc *p)
273 {
274 
275 	if (p->p_sysent->sv_machine_arch != NULL)
276 		return (p->p_sysent->sv_machine_arch(p));
277 #ifdef COMPAT_FREEBSD32
278 	if (SV_PROC_FLAG(p, SV_ILP32))
279 		return (MACHINE_ARCH32);
280 #endif
281 	return (MACHINE_ARCH);
282 }
283 
284 static int
285 sysctl_hw_machine_arch(SYSCTL_HANDLER_ARGS)
286 {
287 	const char *machine_arch;
288 
289 	if (adaptive_machine_arch)
290 		machine_arch = proc_machine_arch(curproc);
291 	else
292 		machine_arch = MACHINE_ARCH;
293 	return (SYSCTL_OUT(req, machine_arch, strlen(machine_arch) + 1));
294 }
295 SYSCTL_PROC(_hw, HW_MACHINE_ARCH, machine_arch, CTLTYPE_STRING | CTLFLAG_RD |
296     CTLFLAG_MPSAFE, NULL, 0, sysctl_hw_machine_arch, "A",
297     "System architecture");
298 
299 #ifndef MACHINE_ARCHES
300 #ifdef COMPAT_FREEBSD32
301 #define	MACHINE_ARCHES	MACHINE_ARCH " " MACHINE_ARCH32
302 #else
303 #define	MACHINE_ARCHES	MACHINE_ARCH
304 #endif
305 #endif
306 
307 SYSCTL_STRING(_kern, OID_AUTO, supported_archs, CTLFLAG_RD | CTLFLAG_MPSAFE,
308     MACHINE_ARCHES, 0, "Supported architectures for binaries");
309 
310 static int
311 sysctl_hostname(SYSCTL_HANDLER_ARGS)
312 {
313 	struct prison *pr, *cpr;
314 	size_t pr_offset;
315 	char tmpname[MAXHOSTNAMELEN];
316 	int descend, error, len;
317 
318 	/*
319 	 * This function can set: hostname domainname hostuuid.
320 	 * Keep that in mind when comments say "hostname".
321 	 */
322 	pr_offset = (size_t)arg1;
323 	len = arg2;
324 	KASSERT(len <= sizeof(tmpname),
325 	    ("length %d too long for %s", len, __func__));
326 
327 	pr = req->td->td_ucred->cr_prison;
328 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME) && req->newptr)
329 		return (EPERM);
330 	/*
331 	 * Make a local copy of hostname to get/set so we don't have to hold
332 	 * the jail mutex during the sysctl copyin/copyout activities.
333 	 */
334 	mtx_lock(&pr->pr_mtx);
335 	bcopy((char *)pr + pr_offset, tmpname, len);
336 	mtx_unlock(&pr->pr_mtx);
337 
338 	error = sysctl_handle_string(oidp, tmpname, len, req);
339 
340 	if (req->newptr != NULL && error == 0) {
341 		/*
342 		 * Copy the locally set hostname to all jails that share
343 		 * this host info.
344 		 */
345 		sx_slock(&allprison_lock);
346 		while (!(pr->pr_flags & PR_HOST))
347 			pr = pr->pr_parent;
348 		mtx_lock(&pr->pr_mtx);
349 		bcopy(tmpname, (char *)pr + pr_offset, len);
350 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
351 			if (cpr->pr_flags & PR_HOST)
352 				descend = 0;
353 			else
354 				bcopy(tmpname, (char *)cpr + pr_offset, len);
355 		mtx_unlock(&pr->pr_mtx);
356 		sx_sunlock(&allprison_lock);
357 	}
358 	return (error);
359 }
360 
361 SYSCTL_PROC(_kern, KERN_HOSTNAME, hostname,
362     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
363     (void *)(offsetof(struct prison, pr_hostname)), MAXHOSTNAMELEN,
364     sysctl_hostname, "A", "Hostname");
365 SYSCTL_PROC(_kern, KERN_NISDOMAINNAME, domainname,
366     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
367     (void *)(offsetof(struct prison, pr_domainname)), MAXHOSTNAMELEN,
368     sysctl_hostname, "A", "Name of the current YP/NIS domain");
369 SYSCTL_PROC(_kern, KERN_HOSTUUID, hostuuid,
370     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_CAPRD | CTLFLAG_MPSAFE,
371     (void *)(offsetof(struct prison, pr_hostuuid)), HOSTUUIDLEN,
372     sysctl_hostname, "A", "Host UUID");
373 
374 static int	regression_securelevel_nonmonotonic = 0;
375 
376 #ifdef REGRESSION
377 SYSCTL_INT(_regression, OID_AUTO, securelevel_nonmonotonic, CTLFLAG_RW,
378     &regression_securelevel_nonmonotonic, 0, "securelevel may be lowered");
379 #endif
380 
381 static int
382 sysctl_kern_securelvl(SYSCTL_HANDLER_ARGS)
383 {
384 	struct prison *pr, *cpr;
385 	int descend, error, level;
386 
387 	pr = req->td->td_ucred->cr_prison;
388 
389 	/*
390 	 * Reading the securelevel is easy, since the current jail's level
391 	 * is known to be at least as secure as any higher levels.  Perform
392 	 * a lockless read since the securelevel is an integer.
393 	 */
394 	level = pr->pr_securelevel;
395 	error = sysctl_handle_int(oidp, &level, 0, req);
396 	if (error || !req->newptr)
397 		return (error);
398 	/* Permit update only if the new securelevel exceeds the old. */
399 	sx_slock(&allprison_lock);
400 	mtx_lock(&pr->pr_mtx);
401 	if (!regression_securelevel_nonmonotonic &&
402 	    level < pr->pr_securelevel) {
403 		mtx_unlock(&pr->pr_mtx);
404 		sx_sunlock(&allprison_lock);
405 		return (EPERM);
406 	}
407 	pr->pr_securelevel = level;
408 	/*
409 	 * Set all child jails to be at least this level, but do not lower
410 	 * them (even if regression_securelevel_nonmonotonic).
411 	 */
412 	FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend) {
413 		if (cpr->pr_securelevel < level)
414 			cpr->pr_securelevel = level;
415 	}
416 	mtx_unlock(&pr->pr_mtx);
417 	sx_sunlock(&allprison_lock);
418 	return (error);
419 }
420 
421 SYSCTL_PROC(_kern, KERN_SECURELVL, securelevel,
422     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE, 0, 0,
423     sysctl_kern_securelvl, "I",
424     "Current secure level");
425 
426 #ifdef INCLUDE_CONFIG_FILE
427 /* Actual kernel configuration options. */
428 extern char kernconfstring[];
429 
430 SYSCTL_STRING(_kern, OID_AUTO, conftxt, CTLFLAG_RD | CTLFLAG_MPSAFE,
431     kernconfstring, 0, "Kernel configuration file");
432 #endif
433 
434 static int
435 sysctl_hostid(SYSCTL_HANDLER_ARGS)
436 {
437 	struct prison *pr, *cpr;
438 	u_long tmpid;
439 	int descend, error;
440 
441 	/*
442 	 * Like sysctl_hostname, except it operates on a u_long
443 	 * instead of a string, and is used only for hostid.
444 	 */
445 	pr = req->td->td_ucred->cr_prison;
446 	if (!(pr->pr_allow & PR_ALLOW_SET_HOSTNAME) && req->newptr)
447 		return (EPERM);
448 	tmpid = pr->pr_hostid;
449 	error = sysctl_handle_long(oidp, &tmpid, 0, req);
450 
451 	if (req->newptr != NULL && error == 0) {
452 		sx_slock(&allprison_lock);
453 		while (!(pr->pr_flags & PR_HOST))
454 			pr = pr->pr_parent;
455 		mtx_lock(&pr->pr_mtx);
456 		pr->pr_hostid = tmpid;
457 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
458 			if (cpr->pr_flags & PR_HOST)
459 				descend = 0;
460 			else
461 				cpr->pr_hostid = tmpid;
462 		mtx_unlock(&pr->pr_mtx);
463 		sx_sunlock(&allprison_lock);
464 	}
465 	return (error);
466 }
467 
468 SYSCTL_PROC(_kern, KERN_HOSTID, hostid,
469     CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
470     NULL, 0, sysctl_hostid, "LU", "Host ID");
471 
472 static struct mtx bootid_lk;
473 MTX_SYSINIT(bootid_lock, &bootid_lk, "bootid generator lock", MTX_DEF);
474 
475 static int
476 sysctl_bootid(SYSCTL_HANDLER_ARGS)
477 {
478 	static uint8_t boot_id[16];
479 	static bool initialized = false;
480 
481 	mtx_lock(&bootid_lk);
482 	if (!initialized) {
483 		if (!is_random_seeded()) {
484 			mtx_unlock(&bootid_lk);
485 			return (ENXIO);
486 		}
487 		arc4random_buf(boot_id, sizeof(boot_id));
488 		initialized = true;
489 	}
490 	mtx_unlock(&bootid_lk);
491 
492 	return (SYSCTL_OUT(req, boot_id, sizeof(boot_id)));
493 }
494 SYSCTL_PROC(_kern, OID_AUTO, boot_id,
495     CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD,
496     NULL, 0, sysctl_bootid, "", "Random boot ID");
497 
498 /*
499  * The osrelease string is copied from the global (osrelease in vers.c) into
500  * prison0 by a sysinit and is inherited by child jails if not changed at jail
501  * creation, so we always return the copy from the current prison data.
502  */
503 static int
504 sysctl_osrelease(SYSCTL_HANDLER_ARGS)
505 {
506 	struct prison *pr;
507 
508 	pr = req->td->td_ucred->cr_prison;
509 	return (SYSCTL_OUT(req, pr->pr_osrelease, strlen(pr->pr_osrelease) + 1));
510 
511 }
512 
513 SYSCTL_PROC(_kern, KERN_OSRELEASE, osrelease,
514     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
515     NULL, 0, sysctl_osrelease, "A", "Operating system release");
516 
517 /*
518  * The osreldate number is copied from the global (osreldate in vers.c) into
519  * prison0 by a sysinit and is inherited by child jails if not changed at jail
520  * creation, so we always return the value from the current prison data.
521  */
522 static int
523 sysctl_osreldate(SYSCTL_HANDLER_ARGS)
524 {
525 	struct prison *pr;
526 
527 	pr = req->td->td_ucred->cr_prison;
528 	return (SYSCTL_OUT(req, &pr->pr_osreldate, sizeof(pr->pr_osreldate)));
529 
530 }
531 
532 /*
533  * NOTICE: The *userland* release date is available in
534  * /usr/include/osreldate.h
535  */
536 SYSCTL_PROC(_kern, KERN_OSRELDATE, osreldate,
537     CTLTYPE_INT | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
538     NULL, 0, sysctl_osreldate, "I", "Kernel release date");
539 
540 /*
541  * The build-id is copied from the ELF section .note.gnu.build-id.  The linker
542  * script defines two variables to expose the beginning and end.  LLVM
543  * currently uses a SHA-1 hash, but other formats can be supported by checking
544  * the length of the section.
545  */
546 
547 extern char __build_id_start[];
548 extern char __build_id_end[];
549 
550 #define	BUILD_ID_HEADER_LEN	0x10
551 #define	BUILD_ID_HASH_MAXLEN	0x14
552 
553 static int
554 sysctl_build_id(SYSCTL_HANDLER_ARGS)
555 {
556 	uintptr_t sectionlen = (uintptr_t)(__build_id_end - __build_id_start);
557 	int hashlen;
558 	char buf[2*BUILD_ID_HASH_MAXLEN+1];
559 
560 	/*
561 	 * The ELF note section has a four byte length for the vendor name,
562 	 * four byte length for the value, and a four byte vendor specific
563 	 * type.  The name for the build id is "GNU\0".  We skip the first 16
564 	 * bytes to read the build hash.  We will return the remaining bytes up
565 	 * to 20 (SHA-1) hash size.  If the hash happens to be a custom number
566 	 * of bytes we will pad the value with zeros, as the section should be
567 	 * four byte aligned.
568 	 */
569 	if (sectionlen <= BUILD_ID_HEADER_LEN ||
570 	    sectionlen > (BUILD_ID_HEADER_LEN + BUILD_ID_HASH_MAXLEN)) {
571 		return (ENOENT);
572 	}
573 
574 	hashlen = sectionlen - BUILD_ID_HEADER_LEN;
575 	for (int i = 0; i < hashlen; i++) {
576 		uint8_t c = __build_id_start[i+BUILD_ID_HEADER_LEN];
577 		snprintf(&buf[2*i], 3, "%02x", c);
578 	}
579 
580 	return (SYSCTL_OUT(req, buf, strlen(buf) + 1));
581 }
582 
583 SYSCTL_PROC(_kern, OID_AUTO, build_id,
584     CTLTYPE_STRING | CTLFLAG_CAPRD | CTLFLAG_RD | CTLFLAG_MPSAFE,
585     NULL, 0, sysctl_build_id, "A", "Operating system build-id");
586 
587 SYSCTL_NODE(_kern, OID_AUTO, features, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
588     "Kernel Features");
589 
590 #ifdef COMPAT_FREEBSD4
591 FEATURE(compat_freebsd4, "Compatible with FreeBSD 4");
592 #endif
593 
594 #ifdef COMPAT_FREEBSD5
595 FEATURE(compat_freebsd5, "Compatible with FreeBSD 5");
596 #endif
597 
598 #ifdef COMPAT_FREEBSD6
599 FEATURE(compat_freebsd6, "Compatible with FreeBSD 6");
600 #endif
601 
602 #ifdef COMPAT_FREEBSD7
603 FEATURE(compat_freebsd7, "Compatible with FreeBSD 7");
604 #endif
605 
606 /*
607  * This is really cheating.  These actually live in the libc, something
608  * which I'm not quite sure is a good idea anyway, but in order for
609  * getnext and friends to actually work, we define dummies here.
610  *
611  * XXXRW: These probably should be CTLFLAG_CAPRD.
612  */
613 SYSCTL_STRING(_user, USER_CS_PATH, cs_path, CTLFLAG_RD,
614     "", 0, "PATH that finds all the standard utilities");
615 SYSCTL_INT(_user, USER_BC_BASE_MAX, bc_base_max, CTLFLAG_RD,
616     SYSCTL_NULL_INT_PTR, 0, "Max ibase/obase values in bc(1)");
617 SYSCTL_INT(_user, USER_BC_DIM_MAX, bc_dim_max, CTLFLAG_RD,
618     SYSCTL_NULL_INT_PTR, 0, "Max array size in bc(1)");
619 SYSCTL_INT(_user, USER_BC_SCALE_MAX, bc_scale_max, CTLFLAG_RD,
620     SYSCTL_NULL_INT_PTR, 0, "Max scale value in bc(1)");
621 SYSCTL_INT(_user, USER_BC_STRING_MAX, bc_string_max, CTLFLAG_RD,
622     SYSCTL_NULL_INT_PTR, 0, "Max string length in bc(1)");
623 SYSCTL_INT(_user, USER_COLL_WEIGHTS_MAX, coll_weights_max, CTLFLAG_RD,
624     SYSCTL_NULL_INT_PTR, 0, "Maximum number of weights assigned to an LC_COLLATE locale entry");
625 SYSCTL_INT(_user, USER_EXPR_NEST_MAX, expr_nest_max, CTLFLAG_RD,
626     SYSCTL_NULL_INT_PTR, 0, "");
627 SYSCTL_INT(_user, USER_LINE_MAX, line_max, CTLFLAG_RD,
628     SYSCTL_NULL_INT_PTR, 0, "Max length (bytes) of a text-processing utility's input line");
629 SYSCTL_INT(_user, USER_RE_DUP_MAX, re_dup_max, CTLFLAG_RD,
630     SYSCTL_NULL_INT_PTR, 0, "Maximum number of repeats of a regexp permitted");
631 SYSCTL_INT(_user, USER_POSIX2_VERSION, posix2_version, CTLFLAG_RD,
632     SYSCTL_NULL_INT_PTR, 0,
633     "The version of POSIX 1003.2 with which the system attempts to comply");
634 SYSCTL_INT(_user, USER_POSIX2_C_BIND, posix2_c_bind, CTLFLAG_RD,
635     SYSCTL_NULL_INT_PTR, 0, "Whether C development supports the C bindings option");
636 SYSCTL_INT(_user, USER_POSIX2_C_DEV, posix2_c_dev, CTLFLAG_RD,
637     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the C development utilities option");
638 SYSCTL_INT(_user, USER_POSIX2_CHAR_TERM, posix2_char_term, CTLFLAG_RD,
639     SYSCTL_NULL_INT_PTR, 0, "");
640 SYSCTL_INT(_user, USER_POSIX2_FORT_DEV, posix2_fort_dev, CTLFLAG_RD,
641     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN development utilities");
642 SYSCTL_INT(_user, USER_POSIX2_FORT_RUN, posix2_fort_run, CTLFLAG_RD,
643     SYSCTL_NULL_INT_PTR, 0, "Whether system supports FORTRAN runtime utilities");
644 SYSCTL_INT(_user, USER_POSIX2_LOCALEDEF, posix2_localedef, CTLFLAG_RD,
645     SYSCTL_NULL_INT_PTR, 0, "Whether system supports creation of locales");
646 SYSCTL_INT(_user, USER_POSIX2_SW_DEV, posix2_sw_dev, CTLFLAG_RD,
647     SYSCTL_NULL_INT_PTR, 0, "Whether system supports software development utilities");
648 SYSCTL_INT(_user, USER_POSIX2_UPE, posix2_upe, CTLFLAG_RD,
649     SYSCTL_NULL_INT_PTR, 0, "Whether system supports the user portability utilities");
650 SYSCTL_INT(_user, USER_STREAM_MAX, stream_max, CTLFLAG_RD,
651     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of streams a process may have open at one time");
652 SYSCTL_INT(_user, USER_TZNAME_MAX, tzname_max, CTLFLAG_RD,
653     SYSCTL_NULL_INT_PTR, 0, "Min Maximum number of types supported for timezone names");
654 
655 #include <sys/vnode.h>
656 SYSCTL_INT(_debug_sizeof, OID_AUTO, vnode, CTLFLAG_RD,
657     SYSCTL_NULL_INT_PTR, sizeof(struct vnode), "sizeof(struct vnode)");
658 
659 SYSCTL_INT(_debug_sizeof, OID_AUTO, proc, CTLFLAG_RD,
660     SYSCTL_NULL_INT_PTR, sizeof(struct proc), "sizeof(struct proc)");
661 
662 static int
663 sysctl_kern_pid_max(SYSCTL_HANDLER_ARGS)
664 {
665 	int error, pm;
666 
667 	pm = pid_max;
668 	error = sysctl_handle_int(oidp, &pm, 0, req);
669 	if (error || !req->newptr)
670 		return (error);
671 	sx_xlock(&proctree_lock);
672 	sx_xlock(&allproc_lock);
673 
674 	/*
675 	 * Only permit the values less then PID_MAX.
676 	 * As a safety measure, do not allow to limit the pid_max too much.
677 	 */
678 	if (pm < 300 || pm > PID_MAX)
679 		error = EINVAL;
680 	else
681 		pid_max = pm;
682 	sx_xunlock(&allproc_lock);
683 	sx_xunlock(&proctree_lock);
684 	return (error);
685 }
686 SYSCTL_PROC(_kern, OID_AUTO, pid_max, CTLTYPE_INT |
687     CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
688     0, 0, sysctl_kern_pid_max, "I", "Maximum allowed pid");
689 
690 #include <sys/bio.h>
691 #include <sys/buf.h>
692 SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
693     SYSCTL_NULL_INT_PTR, sizeof(struct bio), "sizeof(struct bio)");
694 SYSCTL_INT(_debug_sizeof, OID_AUTO, buf, CTLFLAG_RD,
695     SYSCTL_NULL_INT_PTR, sizeof(struct buf), "sizeof(struct buf)");
696 
697 #include <sys/user.h>
698 SYSCTL_INT(_debug_sizeof, OID_AUTO, kinfo_proc, CTLFLAG_RD,
699     SYSCTL_NULL_INT_PTR, sizeof(struct kinfo_proc), "sizeof(struct kinfo_proc)");
700 
701 /* Used by kernel debuggers. */
702 const int pcb_size = sizeof(struct pcb);
703 SYSCTL_INT(_debug_sizeof, OID_AUTO, pcb, CTLFLAG_RD,
704     SYSCTL_NULL_INT_PTR, sizeof(struct pcb), "sizeof(struct pcb)");
705 
706 /* XXX compatibility, remove for 6.0 */
707 #include <sys/imgact.h>
708 #include <sys/imgact_elf.h>
709 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
710     &__elfN(fallback_brand), sizeof(__elfN(fallback_brand)),
711     "compatibility for kern.fallback_elf_brand");
712