xref: /dflybsd-src/sys/kern/kern_resource.c (revision 6693db176654a0f25095ec64d0a74d58dcf0e47e)
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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)kern_resource.c	8.5 (Berkeley) 1/21/94
39  * $FreeBSD: src/sys/kern/kern_resource.c,v 1.55.2.5 2001/11/03 01:41:08 ps Exp $
40  * $DragonFly: src/sys/kern/kern_resource.c,v 1.35 2008/05/27 05:25:34 dillon Exp $
41  */
42 
43 #include "opt_compat.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/sysproto.h>
48 #include <sys/file.h>
49 #include <sys/kern_syscall.h>
50 #include <sys/kernel.h>
51 #include <sys/resourcevar.h>
52 #include <sys/malloc.h>
53 #include <sys/proc.h>
54 #include <sys/priv.h>
55 #include <sys/time.h>
56 #include <sys/lockf.h>
57 
58 #include <vm/vm.h>
59 #include <vm/vm_param.h>
60 #include <sys/lock.h>
61 #include <vm/pmap.h>
62 #include <vm/vm_map.h>
63 
64 #include <sys/thread2.h>
65 #include <sys/spinlock2.h>
66 #include <sys/mplock2.h>
67 
68 static int donice (struct proc *chgp, int n);
69 
70 static MALLOC_DEFINE(M_UIDINFO, "uidinfo", "uidinfo structures");
71 #define	UIHASH(uid)	(&uihashtbl[(uid) & uihash])
72 static struct spinlock uihash_lock;
73 static LIST_HEAD(uihashhead, uidinfo) *uihashtbl;
74 static u_long uihash;		/* size of hash table - 1 */
75 
76 static struct uidinfo	*uicreate (uid_t uid);
77 static struct uidinfo	*uilookup (uid_t uid);
78 
79 /*
80  * Resource controls and accounting.
81  */
82 
83 struct getpriority_info {
84 	int low;
85 	int who;
86 };
87 
88 static int getpriority_callback(struct proc *p, void *data);
89 
90 /*
91  * MPALMOSTSAFE
92  */
93 int
94 sys_getpriority(struct getpriority_args *uap)
95 {
96 	struct getpriority_info info;
97 	struct proc *curp = curproc;
98 	struct proc *p;
99 	int low = PRIO_MAX + 1;
100 	int error;
101 
102 	get_mplock();
103 
104 	switch (uap->which) {
105 	case PRIO_PROCESS:
106 		if (uap->who == 0)
107 			p = curp;
108 		else
109 			p = pfind(uap->who);
110 		if (p == 0)
111 			break;
112 		if (!PRISON_CHECK(curp->p_ucred, p->p_ucred))
113 			break;
114 		low = p->p_nice;
115 		break;
116 
117 	case PRIO_PGRP:
118 	{
119 		struct pgrp *pg;
120 
121 		if (uap->who == 0)
122 			pg = curp->p_pgrp;
123 		else if ((pg = pgfind(uap->who)) == NULL)
124 			break;
125 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
126 			if ((PRISON_CHECK(curp->p_ucred, p->p_ucred) && p->p_nice < low))
127 				low = p->p_nice;
128 		}
129 		break;
130 	}
131 	case PRIO_USER:
132 		if (uap->who == 0)
133 			uap->who = curp->p_ucred->cr_uid;
134 		info.low = low;
135 		info.who = uap->who;
136 		allproc_scan(getpriority_callback, &info);
137 		low = info.low;
138 		break;
139 
140 	default:
141 		error = EINVAL;
142 		goto done;
143 	}
144 	if (low == PRIO_MAX + 1) {
145 		error = ESRCH;
146 		goto done;
147 	}
148 	uap->sysmsg_result = low;
149 	error = 0;
150 done:
151 	rel_mplock();
152 	return (error);
153 }
154 
155 /*
156  * Figure out the current lowest nice priority for processes owned
157  * by the specified user.
158  */
159 static
160 int
161 getpriority_callback(struct proc *p, void *data)
162 {
163 	struct getpriority_info *info = data;
164 
165 	if (PRISON_CHECK(curproc->p_ucred, p->p_ucred) &&
166 	    p->p_ucred->cr_uid == info->who &&
167 	    p->p_nice < info->low) {
168 		info->low = p->p_nice;
169 	}
170 	return(0);
171 }
172 
173 struct setpriority_info {
174 	int prio;
175 	int who;
176 	int error;
177 	int found;
178 };
179 
180 static int setpriority_callback(struct proc *p, void *data);
181 
182 /*
183  * MPALMOSTSAFE
184  */
185 int
186 sys_setpriority(struct setpriority_args *uap)
187 {
188 	struct setpriority_info info;
189 	struct proc *curp = curproc;
190 	struct proc *p;
191 	int found = 0, error = 0;
192 
193 	get_mplock();
194 
195 	switch (uap->which) {
196 	case PRIO_PROCESS:
197 		if (uap->who == 0)
198 			p = curp;
199 		else
200 			p = pfind(uap->who);
201 		if (p == 0)
202 			break;
203 		if (!PRISON_CHECK(curp->p_ucred, p->p_ucred))
204 			break;
205 		error = donice(p, uap->prio);
206 		found++;
207 		break;
208 
209 	case PRIO_PGRP:
210 	{
211 		struct pgrp *pg;
212 
213 		if (uap->who == 0)
214 			pg = curp->p_pgrp;
215 		else if ((pg = pgfind(uap->who)) == NULL)
216 			break;
217 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
218 			if (PRISON_CHECK(curp->p_ucred, p->p_ucred)) {
219 				error = donice(p, uap->prio);
220 				found++;
221 			}
222 		}
223 		break;
224 	}
225 	case PRIO_USER:
226 		if (uap->who == 0)
227 			uap->who = curp->p_ucred->cr_uid;
228 		info.prio = uap->prio;
229 		info.who = uap->who;
230 		info.error = 0;
231 		info.found = 0;
232 		allproc_scan(setpriority_callback, &info);
233 		error = info.error;
234 		found = info.found;
235 		break;
236 
237 	default:
238 		error = EINVAL;
239 		found = 1;
240 		break;
241 	}
242 
243 	rel_mplock();
244 	if (found == 0)
245 		error = ESRCH;
246 	return (error);
247 }
248 
249 static
250 int
251 setpriority_callback(struct proc *p, void *data)
252 {
253 	struct setpriority_info *info = data;
254 	int error;
255 
256 	if (p->p_ucred->cr_uid == info->who &&
257 	    PRISON_CHECK(curproc->p_ucred, p->p_ucred)) {
258 		error = donice(p, info->prio);
259 		if (error)
260 			info->error = error;
261 		++info->found;
262 	}
263 	return(0);
264 }
265 
266 static int
267 donice(struct proc *chgp, int n)
268 {
269 	struct proc *curp = curproc;
270 	struct ucred *cr = curp->p_ucred;
271 	struct lwp *lp;
272 
273 	if (cr->cr_uid && cr->cr_ruid &&
274 	    cr->cr_uid != chgp->p_ucred->cr_uid &&
275 	    cr->cr_ruid != chgp->p_ucred->cr_uid)
276 		return (EPERM);
277 	if (n > PRIO_MAX)
278 		n = PRIO_MAX;
279 	if (n < PRIO_MIN)
280 		n = PRIO_MIN;
281 	if (n < chgp->p_nice && priv_check_cred(cr, PRIV_SCHED_SETPRIORITY, 0))
282 		return (EACCES);
283 	chgp->p_nice = n;
284 	FOREACH_LWP_IN_PROC(lp, chgp)
285 		chgp->p_usched->resetpriority(lp);
286 	return (0);
287 }
288 
289 /*
290  * MPALMOSTSAFE
291  */
292 int
293 sys_lwp_rtprio(struct lwp_rtprio_args *uap)
294 {
295 	struct proc *p = curproc;
296 	struct lwp *lp;
297 	struct rtprio rtp;
298 	struct ucred *cr = curthread->td_ucred;
299 	int error;
300 
301 	error = copyin(uap->rtp, &rtp, sizeof(struct rtprio));
302 	if (error)
303 		return error;
304 	if (uap->pid < 0)
305 		return EINVAL;
306 
307 	get_mplock();
308 	if (uap->pid == 0) {
309 		/* curproc already loaded on p */
310 	} else {
311 		p = pfind(uap->pid);
312 	}
313 
314 	if (p == NULL) {
315 		error = ESRCH;
316 		goto done;
317 	}
318 
319 	if (uap->tid < -1) {
320 		error = EINVAL;
321 		goto done;
322 	}
323 	if (uap->tid == -1) {
324 		/*
325 		 * sadly, tid can be 0 so we can't use 0 here
326 		 * like sys_rtprio()
327 		 */
328 		lp = curthread->td_lwp;
329 	} else {
330 		lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, uap->tid);
331 		if (lp == NULL) {
332 			error = ESRCH;
333 			goto done;
334 		}
335 	}
336 
337 	switch (uap->function) {
338 	case RTP_LOOKUP:
339 		error = copyout(&lp->lwp_rtprio, uap->rtp,
340 				sizeof(struct rtprio));
341 		break;
342 	case RTP_SET:
343 		if (cr->cr_uid && cr->cr_ruid &&
344 		    cr->cr_uid != p->p_ucred->cr_uid &&
345 		    cr->cr_ruid != p->p_ucred->cr_uid) {
346 			error = EPERM;
347 			break;
348 		}
349 		/* disallow setting rtprio in most cases if not superuser */
350 		if (priv_check_cred(cr, PRIV_SCHED_RTPRIO, 0)) {
351 			/* can't set someone else's */
352 			if (uap->pid) { /* XXX */
353 				error = EPERM;
354 				break;
355 			}
356 			/* can't set realtime priority */
357 /*
358  * Realtime priority has to be restricted for reasons which should be
359  * obvious. However, for idle priority, there is a potential for
360  * system deadlock if an idleprio process gains a lock on a resource
361  * that other processes need (and the idleprio process can't run
362  * due to a CPU-bound normal process). Fix me! XXX
363  */
364  			if (RTP_PRIO_IS_REALTIME(rtp.type)) {
365 				error = EPERM;
366 				break;
367 			}
368 		}
369 		switch (rtp.type) {
370 #ifdef RTP_PRIO_FIFO
371 		case RTP_PRIO_FIFO:
372 #endif
373 		case RTP_PRIO_REALTIME:
374 		case RTP_PRIO_NORMAL:
375 		case RTP_PRIO_IDLE:
376 			if (rtp.prio > RTP_PRIO_MAX)
377 				return EINVAL;
378 			lp->lwp_rtprio = rtp;
379 			error = 0;
380 			break;
381 		default:
382 			error = EINVAL;
383 			break;
384 		}
385 		break;
386 	default:
387 		error = EINVAL;
388 		break;
389 	}
390 
391 done:
392 	rel_mplock();
393 	return (error);
394 }
395 
396 /*
397  * Set realtime priority
398  *
399  * MPALMOSTSAFE
400  */
401 int
402 sys_rtprio(struct rtprio_args *uap)
403 {
404 	struct proc *curp = curproc;
405 	struct proc *p;
406 	struct lwp *lp;
407 	struct ucred *cr = curthread->td_ucred;
408 	struct rtprio rtp;
409 	int error;
410 
411 	error = copyin(uap->rtp, &rtp, sizeof(struct rtprio));
412 	if (error)
413 		return (error);
414 
415 	get_mplock();
416 	if (uap->pid == 0)
417 		p = curp;
418 	else
419 		p = pfind(uap->pid);
420 
421 	if (p == NULL) {
422 		error = ESRCH;
423 		goto done;
424 	}
425 
426 	/* XXX lwp */
427 	lp = FIRST_LWP_IN_PROC(p);
428 	switch (uap->function) {
429 	case RTP_LOOKUP:
430 		error = copyout(&lp->lwp_rtprio, uap->rtp,
431 				sizeof(struct rtprio));
432 		break;
433 	case RTP_SET:
434 		if (cr->cr_uid && cr->cr_ruid &&
435 		    cr->cr_uid != p->p_ucred->cr_uid &&
436 		    cr->cr_ruid != p->p_ucred->cr_uid) {
437 			error = EPERM;
438 			break;
439 		}
440 		/* disallow setting rtprio in most cases if not superuser */
441 		if (priv_check_cred(cr, PRIV_SCHED_RTPRIO, 0)) {
442 			/* can't set someone else's */
443 			if (uap->pid) {
444 				error = EPERM;
445 				break;
446 			}
447 			/* can't set realtime priority */
448 /*
449  * Realtime priority has to be restricted for reasons which should be
450  * obvious. However, for idle priority, there is a potential for
451  * system deadlock if an idleprio process gains a lock on a resource
452  * that other processes need (and the idleprio process can't run
453  * due to a CPU-bound normal process). Fix me! XXX
454  */
455 			if (RTP_PRIO_IS_REALTIME(rtp.type)) {
456 				error = EPERM;
457 				break;
458 			}
459 		}
460 		switch (rtp.type) {
461 #ifdef RTP_PRIO_FIFO
462 		case RTP_PRIO_FIFO:
463 #endif
464 		case RTP_PRIO_REALTIME:
465 		case RTP_PRIO_NORMAL:
466 		case RTP_PRIO_IDLE:
467 			if (rtp.prio > RTP_PRIO_MAX) {
468 				error = EINVAL;
469 				break;
470 			}
471 			lp->lwp_rtprio = rtp;
472 			error = 0;
473 			break;
474 		default:
475 			error = EINVAL;
476 			break;
477 		}
478 		break;
479 	default:
480 		error = EINVAL;
481 		break;
482 	}
483 done:
484 	rel_mplock();
485 	return (error);
486 }
487 
488 /*
489  * MPSAFE
490  */
491 int
492 sys_setrlimit(struct __setrlimit_args *uap)
493 {
494 	struct rlimit alim;
495 	int error;
496 
497 	error = copyin(uap->rlp, &alim, sizeof(alim));
498 	if (error)
499 		return (error);
500 
501 	error = kern_setrlimit(uap->which, &alim);
502 
503 	return (error);
504 }
505 
506 /*
507  * MPSAFE
508  */
509 int
510 sys_getrlimit(struct __getrlimit_args *uap)
511 {
512 	struct rlimit lim;
513 	int error;
514 
515 	error = kern_getrlimit(uap->which, &lim);
516 
517 	if (error == 0)
518 		error = copyout(&lim, uap->rlp, sizeof(*uap->rlp));
519 	return error;
520 }
521 
522 /*
523  * Transform the running time and tick information in lwp lp's thread into user,
524  * system, and interrupt time usage.
525  *
526  * Since we are limited to statclock tick granularity this is a statisical
527  * calculation which will be correct over the long haul, but should not be
528  * expected to measure fine grained deltas.
529  *
530  * It is possible to catch a lwp in the midst of being created, so
531  * check whether lwp_thread is NULL or not.
532  */
533 void
534 calcru(struct lwp *lp, struct timeval *up, struct timeval *sp)
535 {
536 	struct thread *td;
537 
538 	/*
539 	 * Calculate at the statclock level.  YYY if the thread is owned by
540 	 * another cpu we need to forward the request to the other cpu, or
541 	 * have a token to interlock the information in order to avoid racing
542 	 * thread destruction.
543 	 */
544 	if ((td = lp->lwp_thread) != NULL) {
545 		crit_enter();
546 		up->tv_sec = td->td_uticks / 1000000;
547 		up->tv_usec = td->td_uticks % 1000000;
548 		sp->tv_sec = td->td_sticks / 1000000;
549 		sp->tv_usec = td->td_sticks % 1000000;
550 		crit_exit();
551 	}
552 }
553 
554 /*
555  * Aggregate resource statistics of all lwps of a process.
556  *
557  * proc.p_ru keeps track of all statistics directly related to a proc.  This
558  * consists of RSS usage and nswap information and aggregate numbers for all
559  * former lwps of this proc.
560  *
561  * proc.p_cru is the sum of all stats of reaped children.
562  *
563  * lwp.lwp_ru contains the stats directly related to one specific lwp, meaning
564  * packet, scheduler switch or page fault counts, etc.  This information gets
565  * added to lwp.lwp_proc.p_ru when the lwp exits.
566  */
567 void
568 calcru_proc(struct proc *p, struct rusage *ru)
569 {
570 	struct timeval upt, spt;
571 	long *rip1, *rip2;
572 	struct lwp *lp;
573 
574 	*ru = p->p_ru;
575 
576 	FOREACH_LWP_IN_PROC(lp, p) {
577 		calcru(lp, &upt, &spt);
578 		timevaladd(&ru->ru_utime, &upt);
579 		timevaladd(&ru->ru_stime, &spt);
580 		for (rip1 = &ru->ru_first, rip2 = &lp->lwp_ru.ru_first;
581 		     rip1 <= &ru->ru_last;
582 		     rip1++, rip2++)
583 			*rip1 += *rip2;
584 	}
585 }
586 
587 
588 /*
589  * MPALMOSTSAFE
590  */
591 int
592 sys_getrusage(struct getrusage_args *uap)
593 {
594 	struct rusage ru;
595 	struct rusage *rup;
596 	int error;
597 
598 	get_mplock();
599 
600 	switch (uap->who) {
601 	case RUSAGE_SELF:
602 		rup = &ru;
603 		calcru_proc(curproc, rup);
604 		error = 0;
605 		break;
606 	case RUSAGE_CHILDREN:
607 		rup = &curproc->p_cru;
608 		error = 0;
609 		break;
610 	default:
611 		error = EINVAL;
612 		break;
613 	}
614 	if (error == 0)
615 		error = copyout(rup, uap->rusage, sizeof(struct rusage));
616 	rel_mplock();
617 	return (error);
618 }
619 
620 void
621 ruadd(struct rusage *ru, struct rusage *ru2)
622 {
623 	long *ip, *ip2;
624 	int i;
625 
626 	timevaladd(&ru->ru_utime, &ru2->ru_utime);
627 	timevaladd(&ru->ru_stime, &ru2->ru_stime);
628 	if (ru->ru_maxrss < ru2->ru_maxrss)
629 		ru->ru_maxrss = ru2->ru_maxrss;
630 	ip = &ru->ru_first; ip2 = &ru2->ru_first;
631 	for (i = &ru->ru_last - &ru->ru_first; i >= 0; i--)
632 		*ip++ += *ip2++;
633 }
634 
635 /*
636  * Find the uidinfo structure for a uid.  This structure is used to
637  * track the total resource consumption (process count, socket buffer
638  * size, etc.) for the uid and impose limits.
639  */
640 void
641 uihashinit(void)
642 {
643 	spin_init(&uihash_lock);
644 	uihashtbl = hashinit(maxproc / 16, M_UIDINFO, &uihash);
645 }
646 
647 /*
648  * NOTE: Must be called with uihash_lock held
649  *
650  * MPSAFE
651  */
652 static struct uidinfo *
653 uilookup(uid_t uid)
654 {
655 	struct	uihashhead *uipp;
656 	struct	uidinfo *uip;
657 
658 	uipp = UIHASH(uid);
659 	LIST_FOREACH(uip, uipp, ui_hash) {
660 		if (uip->ui_uid == uid)
661 			break;
662 	}
663 	return (uip);
664 }
665 
666 /*
667  * MPSAFE
668  */
669 static struct uidinfo *
670 uicreate(uid_t uid)
671 {
672 	struct	uidinfo *uip, *tmp;
673 	/*
674 	 * Allocate space and check for a race
675 	 */
676 	MALLOC(uip, struct uidinfo *, sizeof(*uip), M_UIDINFO, M_WAITOK);
677 	/*
678 	 * Initialize structure and enter it into the hash table
679 	 */
680 	spin_init(&uip->ui_lock);
681 	uip->ui_uid = uid;
682 	uip->ui_proccnt = 0;
683 	uip->ui_sbsize = 0;
684 	uip->ui_ref = 1;	/* we're returning a ref */
685 	uip->ui_posixlocks = 0;
686 	varsymset_init(&uip->ui_varsymset, NULL);
687 
688 	/*
689 	 * Somebody may have already created the uidinfo for this
690 	 * uid. If so, return that instead.
691 	 */
692 	spin_lock_wr(&uihash_lock);
693 	tmp = uilookup(uid);
694 	if (tmp != NULL) {
695 		varsymset_clean(&uip->ui_varsymset);
696 		spin_uninit(&uip->ui_lock);
697 		FREE(uip, M_UIDINFO);
698 		uip = tmp;
699 	} else {
700 		LIST_INSERT_HEAD(UIHASH(uid), uip, ui_hash);
701 	}
702 	spin_unlock_wr(&uihash_lock);
703 
704 	return (uip);
705 }
706 
707 /*
708  * MPSAFE
709  */
710 struct uidinfo *
711 uifind(uid_t uid)
712 {
713 	struct	uidinfo *uip;
714 
715 	spin_lock_rd(&uihash_lock);
716 	uip = uilookup(uid);
717 	if (uip == NULL) {
718 		spin_unlock_rd(&uihash_lock);
719 		uip = uicreate(uid);
720 	} else {
721 		uihold(uip);
722 		spin_unlock_rd(&uihash_lock);
723 	}
724 	return (uip);
725 }
726 
727 /*
728  * MPSAFE
729  */
730 static __inline void
731 uifree(struct uidinfo *uip)
732 {
733 	spin_lock_wr(&uihash_lock);
734 
735 	/*
736 	 * Note that we're taking a read lock even though we
737 	 * modify the structure because we know nobody can find
738 	 * it now that we've locked uihash_lock. If somebody
739 	 * can get to it through a stored pointer, the reference
740 	 * count will not be 0 and in that case we don't modify
741 	 * the struct.
742 	 */
743 	spin_lock_rd(&uip->ui_lock);
744 	if (uip->ui_ref != 0) {
745 		/*
746 		 * Someone found the uid and got a ref when we
747 		 * unlocked. No need to free any more.
748 		 */
749 		spin_unlock_rd(&uip->ui_lock);
750 		return;
751 	}
752 	if (uip->ui_sbsize != 0)
753 		/* XXX no %qd in kernel.  Truncate. */
754 		kprintf("freeing uidinfo: uid = %d, sbsize = %ld\n",
755 		    uip->ui_uid, (long)uip->ui_sbsize);
756 	if (uip->ui_proccnt != 0)
757 		kprintf("freeing uidinfo: uid = %d, proccnt = %ld\n",
758 		    uip->ui_uid, uip->ui_proccnt);
759 
760 	LIST_REMOVE(uip, ui_hash);
761 	spin_unlock_wr(&uihash_lock);
762 	varsymset_clean(&uip->ui_varsymset);
763 	lockuninit(&uip->ui_varsymset.vx_lock);
764 	spin_unlock_rd(&uip->ui_lock);
765 	spin_uninit(&uip->ui_lock);
766 	FREE(uip, M_UIDINFO);
767 }
768 
769 /*
770  * MPSAFE
771  */
772 void
773 uihold(struct uidinfo *uip)
774 {
775 	atomic_add_int(&uip->ui_ref, 1);
776 	KKASSERT(uip->ui_ref >= 0);
777 }
778 
779 /*
780  * MPSAFE
781  */
782 void
783 uidrop(struct uidinfo *uip)
784 {
785 	KKASSERT(uip->ui_ref > 0);
786 	if (atomic_fetchadd_int(&uip->ui_ref, -1) == 1) {
787 		uifree(uip);
788 	}
789 }
790 
791 void
792 uireplace(struct uidinfo **puip, struct uidinfo *nuip)
793 {
794 	uidrop(*puip);
795 	*puip = nuip;
796 }
797 
798 /*
799  * Change the count associated with number of processes
800  * a given user is using.  When 'max' is 0, don't enforce a limit
801  */
802 int
803 chgproccnt(struct uidinfo *uip, int diff, int max)
804 {
805 	int ret;
806 	spin_lock_wr(&uip->ui_lock);
807 	/* don't allow them to exceed max, but allow subtraction */
808 	if (diff > 0 && uip->ui_proccnt + diff > max && max != 0) {
809 		ret = 0;
810 	} else {
811 		uip->ui_proccnt += diff;
812 		if (uip->ui_proccnt < 0)
813 			kprintf("negative proccnt for uid = %d\n", uip->ui_uid);
814 		ret = 1;
815 	}
816 	spin_unlock_wr(&uip->ui_lock);
817 	return ret;
818 }
819 
820 /*
821  * Change the total socket buffer size a user has used.
822  */
823 int
824 chgsbsize(struct uidinfo *uip, u_long *hiwat, u_long to, rlim_t max)
825 {
826 	rlim_t new;
827 
828 	spin_lock_wr(&uip->ui_lock);
829 	new = uip->ui_sbsize + to - *hiwat;
830 	KKASSERT(new >= 0);
831 
832 	/*
833 	 * If we are trying to increase the socket buffer size
834 	 * Scale down the hi water mark when we exceed the user's
835 	 * allowed socket buffer space.
836 	 *
837 	 * We can't scale down too much or we will blow up atomic packet
838 	 * operations.
839 	 */
840 	if (to > *hiwat && to > MCLBYTES && new > max) {
841 		to = to * max / new;
842 		if (to < MCLBYTES)
843 			to = MCLBYTES;
844 	}
845 	uip->ui_sbsize = new;
846 	*hiwat = to;
847 	spin_unlock_wr(&uip->ui_lock);
848 	return (1);
849 }
850 
851