xref: /freebsd/sys/kern/kern_resource.c (revision ec65e4f8d0654361df5e97d4de3518edebf76b46)
1 /*-
2  * Copyright (c) 1982, 1986, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)kern_resource.c	8.5 (Berkeley) 1/21/94
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "opt_compat.h"
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/sysproto.h>
45 #include <sys/file.h>
46 #include <sys/kernel.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/mutex.h>
50 #include <sys/priv.h>
51 #include <sys/proc.h>
52 #include <sys/refcount.h>
53 #include <sys/racct.h>
54 #include <sys/resourcevar.h>
55 #include <sys/rwlock.h>
56 #include <sys/sched.h>
57 #include <sys/sx.h>
58 #include <sys/syscallsubr.h>
59 #include <sys/sysctl.h>
60 #include <sys/sysent.h>
61 #include <sys/time.h>
62 #include <sys/umtx.h>
63 
64 #include <vm/vm.h>
65 #include <vm/vm_param.h>
66 #include <vm/pmap.h>
67 #include <vm/vm_map.h>
68 
69 
70 static MALLOC_DEFINE(M_PLIMIT, "plimit", "plimit structures");
71 static MALLOC_DEFINE(M_UIDINFO, "uidinfo", "uidinfo structures");
72 #define	UIHASH(uid)	(&uihashtbl[(uid) & uihash])
73 static struct rwlock uihashtbl_lock;
74 static LIST_HEAD(uihashhead, uidinfo) *uihashtbl;
75 static u_long uihash;		/* size of hash table - 1 */
76 
77 static void	calcru1(struct proc *p, struct rusage_ext *ruxp,
78 		    struct timeval *up, struct timeval *sp);
79 static int	donice(struct thread *td, struct proc *chgp, int n);
80 static struct uidinfo *uilookup(uid_t uid);
81 static void	ruxagg_locked(struct rusage_ext *rux, struct thread *td);
82 
83 /*
84  * Resource controls and accounting.
85  */
86 #ifndef _SYS_SYSPROTO_H_
87 struct getpriority_args {
88 	int	which;
89 	int	who;
90 };
91 #endif
92 int
93 sys_getpriority(struct thread *td, register struct getpriority_args *uap)
94 {
95 	struct proc *p;
96 	struct pgrp *pg;
97 	int error, low;
98 
99 	error = 0;
100 	low = PRIO_MAX + 1;
101 	switch (uap->which) {
102 
103 	case PRIO_PROCESS:
104 		if (uap->who == 0)
105 			low = td->td_proc->p_nice;
106 		else {
107 			p = pfind(uap->who);
108 			if (p == NULL)
109 				break;
110 			if (p_cansee(td, p) == 0)
111 				low = p->p_nice;
112 			PROC_UNLOCK(p);
113 		}
114 		break;
115 
116 	case PRIO_PGRP:
117 		sx_slock(&proctree_lock);
118 		if (uap->who == 0) {
119 			pg = td->td_proc->p_pgrp;
120 			PGRP_LOCK(pg);
121 		} else {
122 			pg = pgfind(uap->who);
123 			if (pg == NULL) {
124 				sx_sunlock(&proctree_lock);
125 				break;
126 			}
127 		}
128 		sx_sunlock(&proctree_lock);
129 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
130 			PROC_LOCK(p);
131 			if (p->p_state == PRS_NORMAL &&
132 			    p_cansee(td, p) == 0) {
133 				if (p->p_nice < low)
134 					low = p->p_nice;
135 			}
136 			PROC_UNLOCK(p);
137 		}
138 		PGRP_UNLOCK(pg);
139 		break;
140 
141 	case PRIO_USER:
142 		if (uap->who == 0)
143 			uap->who = td->td_ucred->cr_uid;
144 		sx_slock(&allproc_lock);
145 		FOREACH_PROC_IN_SYSTEM(p) {
146 			PROC_LOCK(p);
147 			if (p->p_state == PRS_NORMAL &&
148 			    p_cansee(td, p) == 0 &&
149 			    p->p_ucred->cr_uid == uap->who) {
150 				if (p->p_nice < low)
151 					low = p->p_nice;
152 			}
153 			PROC_UNLOCK(p);
154 		}
155 		sx_sunlock(&allproc_lock);
156 		break;
157 
158 	default:
159 		error = EINVAL;
160 		break;
161 	}
162 	if (low == PRIO_MAX + 1 && error == 0)
163 		error = ESRCH;
164 	td->td_retval[0] = low;
165 	return (error);
166 }
167 
168 #ifndef _SYS_SYSPROTO_H_
169 struct setpriority_args {
170 	int	which;
171 	int	who;
172 	int	prio;
173 };
174 #endif
175 int
176 sys_setpriority(struct thread *td, struct setpriority_args *uap)
177 {
178 	struct proc *curp, *p;
179 	struct pgrp *pg;
180 	int found = 0, error = 0;
181 
182 	curp = td->td_proc;
183 	switch (uap->which) {
184 	case PRIO_PROCESS:
185 		if (uap->who == 0) {
186 			PROC_LOCK(curp);
187 			error = donice(td, curp, uap->prio);
188 			PROC_UNLOCK(curp);
189 		} else {
190 			p = pfind(uap->who);
191 			if (p == NULL)
192 				break;
193 			error = p_cansee(td, p);
194 			if (error == 0)
195 				error = donice(td, p, uap->prio);
196 			PROC_UNLOCK(p);
197 		}
198 		found++;
199 		break;
200 
201 	case PRIO_PGRP:
202 		sx_slock(&proctree_lock);
203 		if (uap->who == 0) {
204 			pg = curp->p_pgrp;
205 			PGRP_LOCK(pg);
206 		} else {
207 			pg = pgfind(uap->who);
208 			if (pg == NULL) {
209 				sx_sunlock(&proctree_lock);
210 				break;
211 			}
212 		}
213 		sx_sunlock(&proctree_lock);
214 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
215 			PROC_LOCK(p);
216 			if (p->p_state == PRS_NORMAL &&
217 			    p_cansee(td, p) == 0) {
218 				error = donice(td, p, uap->prio);
219 				found++;
220 			}
221 			PROC_UNLOCK(p);
222 		}
223 		PGRP_UNLOCK(pg);
224 		break;
225 
226 	case PRIO_USER:
227 		if (uap->who == 0)
228 			uap->who = td->td_ucred->cr_uid;
229 		sx_slock(&allproc_lock);
230 		FOREACH_PROC_IN_SYSTEM(p) {
231 			PROC_LOCK(p);
232 			if (p->p_state == PRS_NORMAL &&
233 			    p->p_ucred->cr_uid == uap->who &&
234 			    p_cansee(td, p) == 0) {
235 				error = donice(td, p, uap->prio);
236 				found++;
237 			}
238 			PROC_UNLOCK(p);
239 		}
240 		sx_sunlock(&allproc_lock);
241 		break;
242 
243 	default:
244 		error = EINVAL;
245 		break;
246 	}
247 	if (found == 0 && error == 0)
248 		error = ESRCH;
249 	return (error);
250 }
251 
252 /*
253  * Set "nice" for a (whole) process.
254  */
255 static int
256 donice(struct thread *td, struct proc *p, int n)
257 {
258 	int error;
259 
260 	PROC_LOCK_ASSERT(p, MA_OWNED);
261 	if ((error = p_cansched(td, p)))
262 		return (error);
263 	if (n > PRIO_MAX)
264 		n = PRIO_MAX;
265 	if (n < PRIO_MIN)
266 		n = PRIO_MIN;
267 	if (n < p->p_nice && priv_check(td, PRIV_SCHED_SETPRIORITY) != 0)
268 		return (EACCES);
269 	sched_nice(p, n);
270 	return (0);
271 }
272 
273 static int unprivileged_idprio;
274 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_idprio, CTLFLAG_RW,
275     &unprivileged_idprio, 0, "Allow non-root users to set an idle priority");
276 
277 /*
278  * Set realtime priority for LWP.
279  */
280 #ifndef _SYS_SYSPROTO_H_
281 struct rtprio_thread_args {
282 	int		function;
283 	lwpid_t		lwpid;
284 	struct rtprio	*rtp;
285 };
286 #endif
287 int
288 sys_rtprio_thread(struct thread *td, struct rtprio_thread_args *uap)
289 {
290 	struct proc *p;
291 	struct rtprio rtp;
292 	struct thread *td1;
293 	int cierror, error;
294 
295 	/* Perform copyin before acquiring locks if needed. */
296 	if (uap->function == RTP_SET)
297 		cierror = copyin(uap->rtp, &rtp, sizeof(struct rtprio));
298 	else
299 		cierror = 0;
300 
301 	if (uap->lwpid == 0 || uap->lwpid == td->td_tid) {
302 		p = td->td_proc;
303 		td1 = td;
304 		PROC_LOCK(p);
305 	} else {
306 		/* Only look up thread in current process */
307 		td1 = tdfind(uap->lwpid, curproc->p_pid);
308 		if (td1 == NULL)
309 			return (ESRCH);
310 		p = td1->td_proc;
311 	}
312 
313 	switch (uap->function) {
314 	case RTP_LOOKUP:
315 		if ((error = p_cansee(td, p)))
316 			break;
317 		pri_to_rtp(td1, &rtp);
318 		PROC_UNLOCK(p);
319 		return (copyout(&rtp, uap->rtp, sizeof(struct rtprio)));
320 	case RTP_SET:
321 		if ((error = p_cansched(td, p)) || (error = cierror))
322 			break;
323 
324 		/* Disallow setting rtprio in most cases if not superuser. */
325 
326 		/*
327 		 * Realtime priority has to be restricted for reasons which
328 		 * should be obvious.  However, for idleprio processes, there is
329 		 * a potential for system deadlock if an idleprio process gains
330 		 * a lock on a resource that other processes need (and the
331 		 * idleprio process can't run due to a CPU-bound normal
332 		 * process).  Fix me!  XXX
333 		 *
334 		 * This problem is not only related to idleprio process.
335 		 * A user level program can obtain a file lock and hold it
336 		 * indefinitely.  Additionally, without idleprio processes it is
337 		 * still conceivable that a program with low priority will never
338 		 * get to run.  In short, allowing this feature might make it
339 		 * easier to lock a resource indefinitely, but it is not the
340 		 * only thing that makes it possible.
341 		 */
342 		if (RTP_PRIO_BASE(rtp.type) == RTP_PRIO_REALTIME ||
343 		    (RTP_PRIO_BASE(rtp.type) == RTP_PRIO_IDLE &&
344 		    unprivileged_idprio == 0)) {
345 			error = priv_check(td, PRIV_SCHED_RTPRIO);
346 			if (error)
347 				break;
348 		}
349 		error = rtp_to_pri(&rtp, td1);
350 		break;
351 	default:
352 		error = EINVAL;
353 		break;
354 	}
355 	PROC_UNLOCK(p);
356 	return (error);
357 }
358 
359 /*
360  * Set realtime priority.
361  */
362 #ifndef _SYS_SYSPROTO_H_
363 struct rtprio_args {
364 	int		function;
365 	pid_t		pid;
366 	struct rtprio	*rtp;
367 };
368 #endif
369 int
370 sys_rtprio(struct thread *td, register struct rtprio_args *uap)
371 {
372 	struct proc *p;
373 	struct thread *tdp;
374 	struct rtprio rtp;
375 	int cierror, error;
376 
377 	/* Perform copyin before acquiring locks if needed. */
378 	if (uap->function == RTP_SET)
379 		cierror = copyin(uap->rtp, &rtp, sizeof(struct rtprio));
380 	else
381 		cierror = 0;
382 
383 	if (uap->pid == 0) {
384 		p = td->td_proc;
385 		PROC_LOCK(p);
386 	} else {
387 		p = pfind(uap->pid);
388 		if (p == NULL)
389 			return (ESRCH);
390 	}
391 
392 	switch (uap->function) {
393 	case RTP_LOOKUP:
394 		if ((error = p_cansee(td, p)))
395 			break;
396 		/*
397 		 * Return OUR priority if no pid specified,
398 		 * or if one is, report the highest priority
399 		 * in the process.  There isn't much more you can do as
400 		 * there is only room to return a single priority.
401 		 * Note: specifying our own pid is not the same
402 		 * as leaving it zero.
403 		 */
404 		if (uap->pid == 0) {
405 			pri_to_rtp(td, &rtp);
406 		} else {
407 			struct rtprio rtp2;
408 
409 			rtp.type = RTP_PRIO_IDLE;
410 			rtp.prio = RTP_PRIO_MAX;
411 			FOREACH_THREAD_IN_PROC(p, tdp) {
412 				pri_to_rtp(tdp, &rtp2);
413 				if (rtp2.type <  rtp.type ||
414 				    (rtp2.type == rtp.type &&
415 				    rtp2.prio < rtp.prio)) {
416 					rtp.type = rtp2.type;
417 					rtp.prio = rtp2.prio;
418 				}
419 			}
420 		}
421 		PROC_UNLOCK(p);
422 		return (copyout(&rtp, uap->rtp, sizeof(struct rtprio)));
423 	case RTP_SET:
424 		if ((error = p_cansched(td, p)) || (error = cierror))
425 			break;
426 
427 		/*
428 		 * Disallow setting rtprio in most cases if not superuser.
429 		 * See the comment in sys_rtprio_thread about idprio
430 		 * threads holding a lock.
431 		 */
432 		if (RTP_PRIO_BASE(rtp.type) == RTP_PRIO_REALTIME ||
433 		    (RTP_PRIO_BASE(rtp.type) == RTP_PRIO_IDLE &&
434 		    !unprivileged_idprio)) {
435 			error = priv_check(td, PRIV_SCHED_RTPRIO);
436 			if (error)
437 				break;
438 		}
439 
440 		/*
441 		 * If we are setting our own priority, set just our
442 		 * thread but if we are doing another process,
443 		 * do all the threads on that process. If we
444 		 * specify our own pid we do the latter.
445 		 */
446 		if (uap->pid == 0) {
447 			error = rtp_to_pri(&rtp, td);
448 		} else {
449 			FOREACH_THREAD_IN_PROC(p, td) {
450 				if ((error = rtp_to_pri(&rtp, td)) != 0)
451 					break;
452 			}
453 		}
454 		break;
455 	default:
456 		error = EINVAL;
457 		break;
458 	}
459 	PROC_UNLOCK(p);
460 	return (error);
461 }
462 
463 int
464 rtp_to_pri(struct rtprio *rtp, struct thread *td)
465 {
466 	u_char  newpri, oldclass, oldpri;
467 
468 	switch (RTP_PRIO_BASE(rtp->type)) {
469 	case RTP_PRIO_REALTIME:
470 		if (rtp->prio > RTP_PRIO_MAX)
471 			return (EINVAL);
472 		newpri = PRI_MIN_REALTIME + rtp->prio;
473 		break;
474 	case RTP_PRIO_NORMAL:
475 		if (rtp->prio > (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE))
476 			return (EINVAL);
477 		newpri = PRI_MIN_TIMESHARE + rtp->prio;
478 		break;
479 	case RTP_PRIO_IDLE:
480 		if (rtp->prio > RTP_PRIO_MAX)
481 			return (EINVAL);
482 		newpri = PRI_MIN_IDLE + rtp->prio;
483 		break;
484 	default:
485 		return (EINVAL);
486 	}
487 
488 	thread_lock(td);
489 	oldclass = td->td_pri_class;
490 	sched_class(td, rtp->type);	/* XXX fix */
491 	oldpri = td->td_user_pri;
492 	sched_user_prio(td, newpri);
493 	if (td->td_user_pri != oldpri && (oldclass != RTP_PRIO_NORMAL ||
494 	    td->td_pri_class != RTP_PRIO_NORMAL))
495 		sched_prio(td, td->td_user_pri);
496 	if (TD_ON_UPILOCK(td) && oldpri != newpri) {
497 		critical_enter();
498 		thread_unlock(td);
499 		umtx_pi_adjust(td, oldpri);
500 		critical_exit();
501 	} else
502 		thread_unlock(td);
503 	return (0);
504 }
505 
506 void
507 pri_to_rtp(struct thread *td, struct rtprio *rtp)
508 {
509 
510 	thread_lock(td);
511 	switch (PRI_BASE(td->td_pri_class)) {
512 	case PRI_REALTIME:
513 		rtp->prio = td->td_base_user_pri - PRI_MIN_REALTIME;
514 		break;
515 	case PRI_TIMESHARE:
516 		rtp->prio = td->td_base_user_pri - PRI_MIN_TIMESHARE;
517 		break;
518 	case PRI_IDLE:
519 		rtp->prio = td->td_base_user_pri - PRI_MIN_IDLE;
520 		break;
521 	default:
522 		break;
523 	}
524 	rtp->type = td->td_pri_class;
525 	thread_unlock(td);
526 }
527 
528 #if defined(COMPAT_43)
529 #ifndef _SYS_SYSPROTO_H_
530 struct osetrlimit_args {
531 	u_int	which;
532 	struct	orlimit *rlp;
533 };
534 #endif
535 int
536 osetrlimit(struct thread *td, register struct osetrlimit_args *uap)
537 {
538 	struct orlimit olim;
539 	struct rlimit lim;
540 	int error;
541 
542 	if ((error = copyin(uap->rlp, &olim, sizeof(struct orlimit))))
543 		return (error);
544 	lim.rlim_cur = olim.rlim_cur;
545 	lim.rlim_max = olim.rlim_max;
546 	error = kern_setrlimit(td, uap->which, &lim);
547 	return (error);
548 }
549 
550 #ifndef _SYS_SYSPROTO_H_
551 struct ogetrlimit_args {
552 	u_int	which;
553 	struct	orlimit *rlp;
554 };
555 #endif
556 int
557 ogetrlimit(struct thread *td, register struct ogetrlimit_args *uap)
558 {
559 	struct orlimit olim;
560 	struct rlimit rl;
561 	int error;
562 
563 	if (uap->which >= RLIM_NLIMITS)
564 		return (EINVAL);
565 	lim_rlimit(td, uap->which, &rl);
566 
567 	/*
568 	 * XXX would be more correct to convert only RLIM_INFINITY to the
569 	 * old RLIM_INFINITY and fail with EOVERFLOW for other larger
570 	 * values.  Most 64->32 and 32->16 conversions, including not
571 	 * unimportant ones of uids are even more broken than what we
572 	 * do here (they blindly truncate).  We don't do this correctly
573 	 * here since we have little experience with EOVERFLOW yet.
574 	 * Elsewhere, getuid() can't fail...
575 	 */
576 	olim.rlim_cur = rl.rlim_cur > 0x7fffffff ? 0x7fffffff : rl.rlim_cur;
577 	olim.rlim_max = rl.rlim_max > 0x7fffffff ? 0x7fffffff : rl.rlim_max;
578 	error = copyout(&olim, uap->rlp, sizeof(olim));
579 	return (error);
580 }
581 #endif /* COMPAT_43 */
582 
583 #ifndef _SYS_SYSPROTO_H_
584 struct __setrlimit_args {
585 	u_int	which;
586 	struct	rlimit *rlp;
587 };
588 #endif
589 int
590 sys_setrlimit(struct thread *td, register struct __setrlimit_args *uap)
591 {
592 	struct rlimit alim;
593 	int error;
594 
595 	if ((error = copyin(uap->rlp, &alim, sizeof(struct rlimit))))
596 		return (error);
597 	error = kern_setrlimit(td, uap->which, &alim);
598 	return (error);
599 }
600 
601 static void
602 lim_cb(void *arg)
603 {
604 	struct rlimit rlim;
605 	struct thread *td;
606 	struct proc *p;
607 
608 	p = arg;
609 	PROC_LOCK_ASSERT(p, MA_OWNED);
610 	/*
611 	 * Check if the process exceeds its cpu resource allocation.  If
612 	 * it reaches the max, arrange to kill the process in ast().
613 	 */
614 	if (p->p_cpulimit == RLIM_INFINITY)
615 		return;
616 	PROC_STATLOCK(p);
617 	FOREACH_THREAD_IN_PROC(p, td) {
618 		ruxagg(p, td);
619 	}
620 	PROC_STATUNLOCK(p);
621 	if (p->p_rux.rux_runtime > p->p_cpulimit * cpu_tickrate()) {
622 		lim_rlimit_proc(p, RLIMIT_CPU, &rlim);
623 		if (p->p_rux.rux_runtime >= rlim.rlim_max * cpu_tickrate()) {
624 			killproc(p, "exceeded maximum CPU limit");
625 		} else {
626 			if (p->p_cpulimit < rlim.rlim_max)
627 				p->p_cpulimit += 5;
628 			kern_psignal(p, SIGXCPU);
629 		}
630 	}
631 	if ((p->p_flag & P_WEXIT) == 0)
632 		callout_reset_sbt(&p->p_limco, SBT_1S, 0,
633 		    lim_cb, p, C_PREL(1));
634 }
635 
636 int
637 kern_setrlimit(struct thread *td, u_int which, struct rlimit *limp)
638 {
639 
640 	return (kern_proc_setrlimit(td, td->td_proc, which, limp));
641 }
642 
643 int
644 kern_proc_setrlimit(struct thread *td, struct proc *p, u_int which,
645     struct rlimit *limp)
646 {
647 	struct plimit *newlim, *oldlim;
648 	register struct rlimit *alimp;
649 	struct rlimit oldssiz;
650 	int error;
651 
652 	if (which >= RLIM_NLIMITS)
653 		return (EINVAL);
654 
655 	/*
656 	 * Preserve historical bugs by treating negative limits as unsigned.
657 	 */
658 	if (limp->rlim_cur < 0)
659 		limp->rlim_cur = RLIM_INFINITY;
660 	if (limp->rlim_max < 0)
661 		limp->rlim_max = RLIM_INFINITY;
662 
663 	oldssiz.rlim_cur = 0;
664 	newlim = lim_alloc();
665 	PROC_LOCK(p);
666 	oldlim = p->p_limit;
667 	alimp = &oldlim->pl_rlimit[which];
668 	if (limp->rlim_cur > alimp->rlim_max ||
669 	    limp->rlim_max > alimp->rlim_max)
670 		if ((error = priv_check(td, PRIV_PROC_SETRLIMIT))) {
671 			PROC_UNLOCK(p);
672 			lim_free(newlim);
673 			return (error);
674 		}
675 	if (limp->rlim_cur > limp->rlim_max)
676 		limp->rlim_cur = limp->rlim_max;
677 	lim_copy(newlim, oldlim);
678 	alimp = &newlim->pl_rlimit[which];
679 
680 	switch (which) {
681 
682 	case RLIMIT_CPU:
683 		if (limp->rlim_cur != RLIM_INFINITY &&
684 		    p->p_cpulimit == RLIM_INFINITY)
685 			callout_reset_sbt(&p->p_limco, SBT_1S, 0,
686 			    lim_cb, p, C_PREL(1));
687 		p->p_cpulimit = limp->rlim_cur;
688 		break;
689 	case RLIMIT_DATA:
690 		if (limp->rlim_cur > maxdsiz)
691 			limp->rlim_cur = maxdsiz;
692 		if (limp->rlim_max > maxdsiz)
693 			limp->rlim_max = maxdsiz;
694 		break;
695 
696 	case RLIMIT_STACK:
697 		if (limp->rlim_cur > maxssiz)
698 			limp->rlim_cur = maxssiz;
699 		if (limp->rlim_max > maxssiz)
700 			limp->rlim_max = maxssiz;
701 		oldssiz = *alimp;
702 		if (p->p_sysent->sv_fixlimit != NULL)
703 			p->p_sysent->sv_fixlimit(&oldssiz,
704 			    RLIMIT_STACK);
705 		break;
706 
707 	case RLIMIT_NOFILE:
708 		if (limp->rlim_cur > maxfilesperproc)
709 			limp->rlim_cur = maxfilesperproc;
710 		if (limp->rlim_max > maxfilesperproc)
711 			limp->rlim_max = maxfilesperproc;
712 		break;
713 
714 	case RLIMIT_NPROC:
715 		if (limp->rlim_cur > maxprocperuid)
716 			limp->rlim_cur = maxprocperuid;
717 		if (limp->rlim_max > maxprocperuid)
718 			limp->rlim_max = maxprocperuid;
719 		if (limp->rlim_cur < 1)
720 			limp->rlim_cur = 1;
721 		if (limp->rlim_max < 1)
722 			limp->rlim_max = 1;
723 		break;
724 	}
725 	if (p->p_sysent->sv_fixlimit != NULL)
726 		p->p_sysent->sv_fixlimit(limp, which);
727 	*alimp = *limp;
728 	p->p_limit = newlim;
729 	PROC_UPDATE_COW(p);
730 	PROC_UNLOCK(p);
731 	lim_free(oldlim);
732 
733 	if (which == RLIMIT_STACK &&
734 	    /*
735 	     * Skip calls from exec_new_vmspace(), done when stack is
736 	     * not mapped yet.
737 	     */
738 	    (td != curthread || (p->p_flag & P_INEXEC) == 0)) {
739 		/*
740 		 * Stack is allocated to the max at exec time with only
741 		 * "rlim_cur" bytes accessible.  If stack limit is going
742 		 * up make more accessible, if going down make inaccessible.
743 		 */
744 		if (limp->rlim_cur != oldssiz.rlim_cur) {
745 			vm_offset_t addr;
746 			vm_size_t size;
747 			vm_prot_t prot;
748 
749 			if (limp->rlim_cur > oldssiz.rlim_cur) {
750 				prot = p->p_sysent->sv_stackprot;
751 				size = limp->rlim_cur - oldssiz.rlim_cur;
752 				addr = p->p_sysent->sv_usrstack -
753 				    limp->rlim_cur;
754 			} else {
755 				prot = VM_PROT_NONE;
756 				size = oldssiz.rlim_cur - limp->rlim_cur;
757 				addr = p->p_sysent->sv_usrstack -
758 				    oldssiz.rlim_cur;
759 			}
760 			addr = trunc_page(addr);
761 			size = round_page(size);
762 			(void)vm_map_protect(&p->p_vmspace->vm_map,
763 			    addr, addr + size, prot, FALSE);
764 		}
765 	}
766 
767 	return (0);
768 }
769 
770 #ifndef _SYS_SYSPROTO_H_
771 struct __getrlimit_args {
772 	u_int	which;
773 	struct	rlimit *rlp;
774 };
775 #endif
776 /* ARGSUSED */
777 int
778 sys_getrlimit(struct thread *td, register struct __getrlimit_args *uap)
779 {
780 	struct rlimit rlim;
781 	int error;
782 
783 	if (uap->which >= RLIM_NLIMITS)
784 		return (EINVAL);
785 	lim_rlimit(td, uap->which, &rlim);
786 	error = copyout(&rlim, uap->rlp, sizeof(struct rlimit));
787 	return (error);
788 }
789 
790 /*
791  * Transform the running time and tick information for children of proc p
792  * into user and system time usage.
793  */
794 void
795 calccru(struct proc *p, struct timeval *up, struct timeval *sp)
796 {
797 
798 	PROC_LOCK_ASSERT(p, MA_OWNED);
799 	calcru1(p, &p->p_crux, up, sp);
800 }
801 
802 /*
803  * Transform the running time and tick information in proc p into user
804  * and system time usage.  If appropriate, include the current time slice
805  * on this CPU.
806  */
807 void
808 calcru(struct proc *p, struct timeval *up, struct timeval *sp)
809 {
810 	struct thread *td;
811 	uint64_t runtime, u;
812 
813 	PROC_LOCK_ASSERT(p, MA_OWNED);
814 	PROC_STATLOCK_ASSERT(p, MA_OWNED);
815 	/*
816 	 * If we are getting stats for the current process, then add in the
817 	 * stats that this thread has accumulated in its current time slice.
818 	 * We reset the thread and CPU state as if we had performed a context
819 	 * switch right here.
820 	 */
821 	td = curthread;
822 	if (td->td_proc == p) {
823 		u = cpu_ticks();
824 		runtime = u - PCPU_GET(switchtime);
825 		td->td_runtime += runtime;
826 		td->td_incruntime += runtime;
827 		PCPU_SET(switchtime, u);
828 	}
829 	/* Make sure the per-thread stats are current. */
830 	FOREACH_THREAD_IN_PROC(p, td) {
831 		if (td->td_incruntime == 0)
832 			continue;
833 		ruxagg(p, td);
834 	}
835 	calcru1(p, &p->p_rux, up, sp);
836 }
837 
838 /* Collect resource usage for a single thread. */
839 void
840 rufetchtd(struct thread *td, struct rusage *ru)
841 {
842 	struct proc *p;
843 	uint64_t runtime, u;
844 
845 	p = td->td_proc;
846 	PROC_STATLOCK_ASSERT(p, MA_OWNED);
847 	THREAD_LOCK_ASSERT(td, MA_OWNED);
848 	/*
849 	 * If we are getting stats for the current thread, then add in the
850 	 * stats that this thread has accumulated in its current time slice.
851 	 * We reset the thread and CPU state as if we had performed a context
852 	 * switch right here.
853 	 */
854 	if (td == curthread) {
855 		u = cpu_ticks();
856 		runtime = u - PCPU_GET(switchtime);
857 		td->td_runtime += runtime;
858 		td->td_incruntime += runtime;
859 		PCPU_SET(switchtime, u);
860 	}
861 	ruxagg(p, td);
862 	*ru = td->td_ru;
863 	calcru1(p, &td->td_rux, &ru->ru_utime, &ru->ru_stime);
864 }
865 
866 static void
867 calcru1(struct proc *p, struct rusage_ext *ruxp, struct timeval *up,
868     struct timeval *sp)
869 {
870 	/* {user, system, interrupt, total} {ticks, usec}: */
871 	uint64_t ut, uu, st, su, it, tt, tu;
872 
873 	ut = ruxp->rux_uticks;
874 	st = ruxp->rux_sticks;
875 	it = ruxp->rux_iticks;
876 	tt = ut + st + it;
877 	if (tt == 0) {
878 		/* Avoid divide by zero */
879 		st = 1;
880 		tt = 1;
881 	}
882 	tu = cputick2usec(ruxp->rux_runtime);
883 	if ((int64_t)tu < 0) {
884 		/* XXX: this should be an assert /phk */
885 		printf("calcru: negative runtime of %jd usec for pid %d (%s)\n",
886 		    (intmax_t)tu, p->p_pid, p->p_comm);
887 		tu = ruxp->rux_tu;
888 	}
889 
890 	if (tu >= ruxp->rux_tu) {
891 		/*
892 		 * The normal case, time increased.
893 		 * Enforce monotonicity of bucketed numbers.
894 		 */
895 		uu = (tu * ut) / tt;
896 		if (uu < ruxp->rux_uu)
897 			uu = ruxp->rux_uu;
898 		su = (tu * st) / tt;
899 		if (su < ruxp->rux_su)
900 			su = ruxp->rux_su;
901 	} else if (tu + 3 > ruxp->rux_tu || 101 * tu > 100 * ruxp->rux_tu) {
902 		/*
903 		 * When we calibrate the cputicker, it is not uncommon to
904 		 * see the presumably fixed frequency increase slightly over
905 		 * time as a result of thermal stabilization and NTP
906 		 * discipline (of the reference clock).  We therefore ignore
907 		 * a bit of backwards slop because we  expect to catch up
908 		 * shortly.  We use a 3 microsecond limit to catch low
909 		 * counts and a 1% limit for high counts.
910 		 */
911 		uu = ruxp->rux_uu;
912 		su = ruxp->rux_su;
913 		tu = ruxp->rux_tu;
914 	} else { /* tu < ruxp->rux_tu */
915 		/*
916 		 * What happened here was likely that a laptop, which ran at
917 		 * a reduced clock frequency at boot, kicked into high gear.
918 		 * The wisdom of spamming this message in that case is
919 		 * dubious, but it might also be indicative of something
920 		 * serious, so lets keep it and hope laptops can be made
921 		 * more truthful about their CPU speed via ACPI.
922 		 */
923 		printf("calcru: runtime went backwards from %ju usec "
924 		    "to %ju usec for pid %d (%s)\n",
925 		    (uintmax_t)ruxp->rux_tu, (uintmax_t)tu,
926 		    p->p_pid, p->p_comm);
927 		uu = (tu * ut) / tt;
928 		su = (tu * st) / tt;
929 	}
930 
931 	ruxp->rux_uu = uu;
932 	ruxp->rux_su = su;
933 	ruxp->rux_tu = tu;
934 
935 	up->tv_sec = uu / 1000000;
936 	up->tv_usec = uu % 1000000;
937 	sp->tv_sec = su / 1000000;
938 	sp->tv_usec = su % 1000000;
939 }
940 
941 #ifndef _SYS_SYSPROTO_H_
942 struct getrusage_args {
943 	int	who;
944 	struct	rusage *rusage;
945 };
946 #endif
947 int
948 sys_getrusage(register struct thread *td, register struct getrusage_args *uap)
949 {
950 	struct rusage ru;
951 	int error;
952 
953 	error = kern_getrusage(td, uap->who, &ru);
954 	if (error == 0)
955 		error = copyout(&ru, uap->rusage, sizeof(struct rusage));
956 	return (error);
957 }
958 
959 int
960 kern_getrusage(struct thread *td, int who, struct rusage *rup)
961 {
962 	struct proc *p;
963 	int error;
964 
965 	error = 0;
966 	p = td->td_proc;
967 	PROC_LOCK(p);
968 	switch (who) {
969 	case RUSAGE_SELF:
970 		rufetchcalc(p, rup, &rup->ru_utime,
971 		    &rup->ru_stime);
972 		break;
973 
974 	case RUSAGE_CHILDREN:
975 		*rup = p->p_stats->p_cru;
976 		calccru(p, &rup->ru_utime, &rup->ru_stime);
977 		break;
978 
979 	case RUSAGE_THREAD:
980 		PROC_STATLOCK(p);
981 		thread_lock(td);
982 		rufetchtd(td, rup);
983 		thread_unlock(td);
984 		PROC_STATUNLOCK(p);
985 		break;
986 
987 	default:
988 		error = EINVAL;
989 	}
990 	PROC_UNLOCK(p);
991 	return (error);
992 }
993 
994 void
995 rucollect(struct rusage *ru, struct rusage *ru2)
996 {
997 	long *ip, *ip2;
998 	int i;
999 
1000 	if (ru->ru_maxrss < ru2->ru_maxrss)
1001 		ru->ru_maxrss = ru2->ru_maxrss;
1002 	ip = &ru->ru_first;
1003 	ip2 = &ru2->ru_first;
1004 	for (i = &ru->ru_last - &ru->ru_first; i >= 0; i--)
1005 		*ip++ += *ip2++;
1006 }
1007 
1008 void
1009 ruadd(struct rusage *ru, struct rusage_ext *rux, struct rusage *ru2,
1010     struct rusage_ext *rux2)
1011 {
1012 
1013 	rux->rux_runtime += rux2->rux_runtime;
1014 	rux->rux_uticks += rux2->rux_uticks;
1015 	rux->rux_sticks += rux2->rux_sticks;
1016 	rux->rux_iticks += rux2->rux_iticks;
1017 	rux->rux_uu += rux2->rux_uu;
1018 	rux->rux_su += rux2->rux_su;
1019 	rux->rux_tu += rux2->rux_tu;
1020 	rucollect(ru, ru2);
1021 }
1022 
1023 /*
1024  * Aggregate tick counts into the proc's rusage_ext.
1025  */
1026 static void
1027 ruxagg_locked(struct rusage_ext *rux, struct thread *td)
1028 {
1029 
1030 	THREAD_LOCK_ASSERT(td, MA_OWNED);
1031 	PROC_STATLOCK_ASSERT(td->td_proc, MA_OWNED);
1032 	rux->rux_runtime += td->td_incruntime;
1033 	rux->rux_uticks += td->td_uticks;
1034 	rux->rux_sticks += td->td_sticks;
1035 	rux->rux_iticks += td->td_iticks;
1036 }
1037 
1038 void
1039 ruxagg(struct proc *p, struct thread *td)
1040 {
1041 
1042 	thread_lock(td);
1043 	ruxagg_locked(&p->p_rux, td);
1044 	ruxagg_locked(&td->td_rux, td);
1045 	td->td_incruntime = 0;
1046 	td->td_uticks = 0;
1047 	td->td_iticks = 0;
1048 	td->td_sticks = 0;
1049 	thread_unlock(td);
1050 }
1051 
1052 /*
1053  * Update the rusage_ext structure and fetch a valid aggregate rusage
1054  * for proc p if storage for one is supplied.
1055  */
1056 void
1057 rufetch(struct proc *p, struct rusage *ru)
1058 {
1059 	struct thread *td;
1060 
1061 	PROC_STATLOCK_ASSERT(p, MA_OWNED);
1062 
1063 	*ru = p->p_ru;
1064 	if (p->p_numthreads > 0)  {
1065 		FOREACH_THREAD_IN_PROC(p, td) {
1066 			ruxagg(p, td);
1067 			rucollect(ru, &td->td_ru);
1068 		}
1069 	}
1070 }
1071 
1072 /*
1073  * Atomically perform a rufetch and a calcru together.
1074  * Consumers, can safely assume the calcru is executed only once
1075  * rufetch is completed.
1076  */
1077 void
1078 rufetchcalc(struct proc *p, struct rusage *ru, struct timeval *up,
1079     struct timeval *sp)
1080 {
1081 
1082 	PROC_STATLOCK(p);
1083 	rufetch(p, ru);
1084 	calcru(p, up, sp);
1085 	PROC_STATUNLOCK(p);
1086 }
1087 
1088 /*
1089  * Allocate a new resource limits structure and initialize its
1090  * reference count and mutex pointer.
1091  */
1092 struct plimit *
1093 lim_alloc()
1094 {
1095 	struct plimit *limp;
1096 
1097 	limp = malloc(sizeof(struct plimit), M_PLIMIT, M_WAITOK);
1098 	refcount_init(&limp->pl_refcnt, 1);
1099 	return (limp);
1100 }
1101 
1102 struct plimit *
1103 lim_hold(struct plimit *limp)
1104 {
1105 
1106 	refcount_acquire(&limp->pl_refcnt);
1107 	return (limp);
1108 }
1109 
1110 void
1111 lim_fork(struct proc *p1, struct proc *p2)
1112 {
1113 
1114 	PROC_LOCK_ASSERT(p1, MA_OWNED);
1115 	PROC_LOCK_ASSERT(p2, MA_OWNED);
1116 
1117 	p2->p_limit = lim_hold(p1->p_limit);
1118 	callout_init_mtx(&p2->p_limco, &p2->p_mtx, 0);
1119 	if (p1->p_cpulimit != RLIM_INFINITY)
1120 		callout_reset_sbt(&p2->p_limco, SBT_1S, 0,
1121 		    lim_cb, p2, C_PREL(1));
1122 }
1123 
1124 void
1125 lim_free(struct plimit *limp)
1126 {
1127 
1128 	if (refcount_release(&limp->pl_refcnt))
1129 		free((void *)limp, M_PLIMIT);
1130 }
1131 
1132 /*
1133  * Make a copy of the plimit structure.
1134  * We share these structures copy-on-write after fork.
1135  */
1136 void
1137 lim_copy(struct plimit *dst, struct plimit *src)
1138 {
1139 
1140 	KASSERT(dst->pl_refcnt <= 1, ("lim_copy to shared limit"));
1141 	bcopy(src->pl_rlimit, dst->pl_rlimit, sizeof(src->pl_rlimit));
1142 }
1143 
1144 /*
1145  * Return the hard limit for a particular system resource.  The
1146  * which parameter specifies the index into the rlimit array.
1147  */
1148 rlim_t
1149 lim_max(struct thread *td, int which)
1150 {
1151 	struct rlimit rl;
1152 
1153 	lim_rlimit(td, which, &rl);
1154 	return (rl.rlim_max);
1155 }
1156 
1157 rlim_t
1158 lim_max_proc(struct proc *p, int which)
1159 {
1160 	struct rlimit rl;
1161 
1162 	lim_rlimit_proc(p, which, &rl);
1163 	return (rl.rlim_max);
1164 }
1165 
1166 /*
1167  * Return the current (soft) limit for a particular system resource.
1168  * The which parameter which specifies the index into the rlimit array
1169  */
1170 rlim_t
1171 lim_cur(struct thread *td, int which)
1172 {
1173 	struct rlimit rl;
1174 
1175 	lim_rlimit(td, which, &rl);
1176 	return (rl.rlim_cur);
1177 }
1178 
1179 rlim_t
1180 lim_cur_proc(struct proc *p, int which)
1181 {
1182 	struct rlimit rl;
1183 
1184 	lim_rlimit_proc(p, which, &rl);
1185 	return (rl.rlim_cur);
1186 }
1187 
1188 /*
1189  * Return a copy of the entire rlimit structure for the system limit
1190  * specified by 'which' in the rlimit structure pointed to by 'rlp'.
1191  */
1192 void
1193 lim_rlimit(struct thread *td, int which, struct rlimit *rlp)
1194 {
1195 	struct proc *p = td->td_proc;
1196 
1197 	MPASS(td == curthread);
1198 	KASSERT(which >= 0 && which < RLIM_NLIMITS,
1199 	    ("request for invalid resource limit"));
1200 	*rlp = td->td_limit->pl_rlimit[which];
1201 	if (p->p_sysent->sv_fixlimit != NULL)
1202 		p->p_sysent->sv_fixlimit(rlp, which);
1203 }
1204 
1205 void
1206 lim_rlimit_proc(struct proc *p, int which, struct rlimit *rlp)
1207 {
1208 
1209 	PROC_LOCK_ASSERT(p, MA_OWNED);
1210 	KASSERT(which >= 0 && which < RLIM_NLIMITS,
1211 	    ("request for invalid resource limit"));
1212 	*rlp = p->p_limit->pl_rlimit[which];
1213 	if (p->p_sysent->sv_fixlimit != NULL)
1214 		p->p_sysent->sv_fixlimit(rlp, which);
1215 }
1216 
1217 void
1218 uihashinit()
1219 {
1220 
1221 	uihashtbl = hashinit(maxproc / 16, M_UIDINFO, &uihash);
1222 	rw_init(&uihashtbl_lock, "uidinfo hash");
1223 }
1224 
1225 /*
1226  * Look up a uidinfo struct for the parameter uid.
1227  * uihashtbl_lock must be locked.
1228  * Increase refcount on uidinfo struct returned.
1229  */
1230 static struct uidinfo *
1231 uilookup(uid_t uid)
1232 {
1233 	struct uihashhead *uipp;
1234 	struct uidinfo *uip;
1235 
1236 	rw_assert(&uihashtbl_lock, RA_LOCKED);
1237 	uipp = UIHASH(uid);
1238 	LIST_FOREACH(uip, uipp, ui_hash)
1239 		if (uip->ui_uid == uid) {
1240 			uihold(uip);
1241 			break;
1242 		}
1243 
1244 	return (uip);
1245 }
1246 
1247 /*
1248  * Find or allocate a struct uidinfo for a particular uid.
1249  * Returns with uidinfo struct referenced.
1250  * uifree() should be called on a struct uidinfo when released.
1251  */
1252 struct uidinfo *
1253 uifind(uid_t uid)
1254 {
1255 	struct uidinfo *new_uip, *uip;
1256 
1257 	rw_rlock(&uihashtbl_lock);
1258 	uip = uilookup(uid);
1259 	rw_runlock(&uihashtbl_lock);
1260 	if (uip != NULL)
1261 		return (uip);
1262 
1263 	new_uip = malloc(sizeof(*new_uip), M_UIDINFO, M_WAITOK | M_ZERO);
1264 	racct_create(&new_uip->ui_racct);
1265 	refcount_init(&new_uip->ui_ref, 1);
1266 	new_uip->ui_uid = uid;
1267 	mtx_init(&new_uip->ui_vmsize_mtx, "ui_vmsize", NULL, MTX_DEF);
1268 
1269 	rw_wlock(&uihashtbl_lock);
1270 	/*
1271 	 * There's a chance someone created our uidinfo while we
1272 	 * were in malloc and not holding the lock, so we have to
1273 	 * make sure we don't insert a duplicate uidinfo.
1274 	 */
1275 	if ((uip = uilookup(uid)) == NULL) {
1276 		LIST_INSERT_HEAD(UIHASH(uid), new_uip, ui_hash);
1277 		rw_wunlock(&uihashtbl_lock);
1278 		uip = new_uip;
1279 	} else {
1280 		rw_wunlock(&uihashtbl_lock);
1281 		racct_destroy(&new_uip->ui_racct);
1282 		mtx_destroy(&new_uip->ui_vmsize_mtx);
1283 		free(new_uip, M_UIDINFO);
1284 	}
1285 	return (uip);
1286 }
1287 
1288 /*
1289  * Place another refcount on a uidinfo struct.
1290  */
1291 void
1292 uihold(struct uidinfo *uip)
1293 {
1294 
1295 	refcount_acquire(&uip->ui_ref);
1296 }
1297 
1298 /*-
1299  * Since uidinfo structs have a long lifetime, we use an
1300  * opportunistic refcounting scheme to avoid locking the lookup hash
1301  * for each release.
1302  *
1303  * If the refcount hits 0, we need to free the structure,
1304  * which means we need to lock the hash.
1305  * Optimal case:
1306  *   After locking the struct and lowering the refcount, if we find
1307  *   that we don't need to free, simply unlock and return.
1308  * Suboptimal case:
1309  *   If refcount lowering results in need to free, bump the count
1310  *   back up, lose the lock and acquire the locks in the proper
1311  *   order to try again.
1312  */
1313 void
1314 uifree(struct uidinfo *uip)
1315 {
1316 	int old;
1317 
1318 	/* Prepare for optimal case. */
1319 	old = uip->ui_ref;
1320 	if (old > 1 && atomic_cmpset_int(&uip->ui_ref, old, old - 1))
1321 		return;
1322 
1323 	/* Prepare for suboptimal case. */
1324 	rw_wlock(&uihashtbl_lock);
1325 	if (refcount_release(&uip->ui_ref) == 0) {
1326 		rw_wunlock(&uihashtbl_lock);
1327 		return;
1328 	}
1329 
1330 	racct_destroy(&uip->ui_racct);
1331 	LIST_REMOVE(uip, ui_hash);
1332 	rw_wunlock(&uihashtbl_lock);
1333 
1334 	if (uip->ui_sbsize != 0)
1335 		printf("freeing uidinfo: uid = %d, sbsize = %ld\n",
1336 		    uip->ui_uid, uip->ui_sbsize);
1337 	if (uip->ui_proccnt != 0)
1338 		printf("freeing uidinfo: uid = %d, proccnt = %ld\n",
1339 		    uip->ui_uid, uip->ui_proccnt);
1340 	if (uip->ui_vmsize != 0)
1341 		printf("freeing uidinfo: uid = %d, swapuse = %lld\n",
1342 		    uip->ui_uid, (unsigned long long)uip->ui_vmsize);
1343 	mtx_destroy(&uip->ui_vmsize_mtx);
1344 	free(uip, M_UIDINFO);
1345 }
1346 
1347 #ifdef RACCT
1348 void
1349 ui_racct_foreach(void (*callback)(struct racct *racct,
1350     void *arg2, void *arg3), void (*pre)(void), void (*post)(void),
1351     void *arg2, void *arg3)
1352 {
1353 	struct uidinfo *uip;
1354 	struct uihashhead *uih;
1355 
1356 	rw_rlock(&uihashtbl_lock);
1357 	if (pre != NULL)
1358 		(pre)();
1359 	for (uih = &uihashtbl[uihash]; uih >= uihashtbl; uih--) {
1360 		LIST_FOREACH(uip, uih, ui_hash) {
1361 			(callback)(uip->ui_racct, arg2, arg3);
1362 		}
1363 	}
1364 	if (post != NULL)
1365 		(post)();
1366 	rw_runlock(&uihashtbl_lock);
1367 }
1368 #endif
1369 
1370 static inline int
1371 chglimit(struct uidinfo *uip, long *limit, int diff, rlim_t max, const char *name)
1372 {
1373 
1374 	/* Don't allow them to exceed max, but allow subtraction. */
1375 	if (diff > 0 && max != 0) {
1376 		if (atomic_fetchadd_long(limit, (long)diff) + diff > max) {
1377 			atomic_subtract_long(limit, (long)diff);
1378 			return (0);
1379 		}
1380 	} else {
1381 		atomic_add_long(limit, (long)diff);
1382 		if (*limit < 0)
1383 			printf("negative %s for uid = %d\n", name, uip->ui_uid);
1384 	}
1385 	return (1);
1386 }
1387 
1388 /*
1389  * Change the count associated with number of processes
1390  * a given user is using.  When 'max' is 0, don't enforce a limit
1391  */
1392 int
1393 chgproccnt(struct uidinfo *uip, int diff, rlim_t max)
1394 {
1395 
1396 	return (chglimit(uip, &uip->ui_proccnt, diff, max, "proccnt"));
1397 }
1398 
1399 /*
1400  * Change the total socket buffer size a user has used.
1401  */
1402 int
1403 chgsbsize(struct uidinfo *uip, u_int *hiwat, u_int to, rlim_t max)
1404 {
1405 	int diff, rv;
1406 
1407 	diff = to - *hiwat;
1408 	if (diff > 0 && max == 0) {
1409 		rv = 0;
1410 	} else {
1411 		rv = chglimit(uip, &uip->ui_sbsize, diff, max, "sbsize");
1412 		if (rv != 0)
1413 			*hiwat = to;
1414 	}
1415 	return (rv);
1416 }
1417 
1418 /*
1419  * Change the count associated with number of pseudo-terminals
1420  * a given user is using.  When 'max' is 0, don't enforce a limit
1421  */
1422 int
1423 chgptscnt(struct uidinfo *uip, int diff, rlim_t max)
1424 {
1425 
1426 	return (chglimit(uip, &uip->ui_ptscnt, diff, max, "ptscnt"));
1427 }
1428 
1429 int
1430 chgkqcnt(struct uidinfo *uip, int diff, rlim_t max)
1431 {
1432 
1433 	return (chglimit(uip, &uip->ui_kqcnt, diff, max, "kqcnt"));
1434 }
1435 
1436 int
1437 chgumtxcnt(struct uidinfo *uip, int diff, rlim_t max)
1438 {
1439 
1440 	return (chglimit(uip, &uip->ui_umtxcnt, diff, max, "umtxcnt"));
1441 }
1442