sys/kern/kern_resource.c

   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
  67 static int donice (struct proc *chgp, int n);
  68
  69 static MALLOC_DEFINE(M_UIDINFO, "uidinfo", "uidinfo structures");
  70 #define UIHASH(uid)     (&uihashtbl[(uid) & uihash])
  71 static struct spinlock uihash_lock;
  72 static LIST_HEAD(uihashhead, uidinfo) *uihashtbl;
  73 static u_long uihash;           /* size of hash table - 1 */
  74
  75 static struct uidinfo   *uicreate (uid_t uid);
  76 static struct uidinfo   *uilookup (uid_t uid);
  77
  78 /*
  79  * Resource controls and accounting.
  80  */
  81
  82 struct getpriority_info {
  83         int low;
  84         int who;
  85 };
  86
  87 static int getpriority_callback(struct proc *p, void *data);
  88
  89 int
  90 sys_getpriority(struct getpriority_args *uap)
  91 {
  92         struct getpriority_info info;
  93         struct proc *curp = curproc;
  94         struct proc *p;
  95         int low = PRIO_MAX + 1;
  96
  97         switch (uap->which) {
  98         case PRIO_PROCESS:
  99                 if (uap->who == 0)
 100                         p = curp;
 101                 else
 102                         p = pfind(uap->who);
 103                 if (p == 0)
 104                         break;
 105                 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred))
 106                         break;
 107                 low = p->p_nice;
 108                 break;
 109
 110         case PRIO_PGRP:
 111         {
 112                 struct pgrp *pg;
 113
 114                 if (uap->who == 0)
 115                         pg = curp->p_pgrp;
 116                 else if ((pg = pgfind(uap->who)) == NULL)
 117                         break;
 118                 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
 119                         if ((PRISON_CHECK(curp->p_ucred, p->p_ucred) && p->p_nice < low))
 120                                 low = p->p_nice;
 121                 }
 122                 break;
 123         }
 124         case PRIO_USER:
 125                 if (uap->who == 0)
 126                         uap->who = curp->p_ucred->cr_uid;
 127                 info.low = low;
 128                 info.who = uap->who;
 129                 allproc_scan(getpriority_callback, &info);
 130                 low = info.low;
 131                 break;
 132
 133         default:
 134                 return (EINVAL);
 135         }
 136         if (low == PRIO_MAX + 1)
 137                 return (ESRCH);
 138         uap->sysmsg_result = low;
 139         return (0);
 140 }
 141
 142 /*
 143  * Figure out the current lowest nice priority for processes owned
 144  * by the specified user.
 145  */
 146 static
 147 int
 148 getpriority_callback(struct proc *p, void *data)
 149 {
 150         struct getpriority_info *info = data;
 151
 152         if (PRISON_CHECK(curproc->p_ucred, p->p_ucred) &&
 153             p->p_ucred->cr_uid == info->who &&
 154             p->p_nice < info->low) {
 155                 info->low = p->p_nice;
 156         }
 157         return(0);
 158 }
 159
 160 struct setpriority_info {
 161         int prio;
 162         int who;
 163         int error;
 164         int found;
 165 };
 166
 167 static int setpriority_callback(struct proc *p, void *data);
 168
 169 int
 170 sys_setpriority(struct setpriority_args *uap)
 171 {
 172         struct setpriority_info info;
 173         struct proc *curp = curproc;
 174         struct proc *p;
 175         int found = 0, error = 0;
 176
 177         switch (uap->which) {
 178         case PRIO_PROCESS:
 179                 if (uap->who == 0)
 180                         p = curp;
 181                 else
 182                         p = pfind(uap->who);
 183                 if (p == 0)
 184                         break;
 185                 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred))
 186                         break;
 187                 error = donice(p, uap->prio);
 188                 found++;
 189                 break;
 190
 191         case PRIO_PGRP:
 192         {
 193                 struct pgrp *pg;
 194
 195                 if (uap->who == 0)
 196                         pg = curp->p_pgrp;
 197                 else if ((pg = pgfind(uap->who)) == NULL)
 198                         break;
 199                 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
 200                         if (PRISON_CHECK(curp->p_ucred, p->p_ucred)) {
 201                                 error = donice(p, uap->prio);
 202                                 found++;
 203                         }
 204                 }
 205                 break;
 206         }
 207         case PRIO_USER:
 208                 if (uap->who == 0)
 209                         uap->who = curp->p_ucred->cr_uid;
 210                 info.prio = uap->prio;
 211                 info.who = uap->who;
 212                 info.error = 0;
 213                 info.found = 0;
 214                 allproc_scan(setpriority_callback, &info);
 215                 error = info.error;
 216                 found = info.found;
 217                 break;
 218
 219         default:
 220                 return (EINVAL);
 221         }
 222         if (found == 0)
 223                 return (ESRCH);
 224         return (error);
 225 }
 226
 227 static
 228 int
 229 setpriority_callback(struct proc *p, void *data)
 230 {
 231         struct setpriority_info *info = data;
 232         int error;
 233
 234         if (p->p_ucred->cr_uid == info->who &&
 235             PRISON_CHECK(curproc->p_ucred, p->p_ucred)) {
 236                 error = donice(p, info->prio);
 237                 if (error)
 238                         info->error = error;
 239                 ++info->found;
 240         }
 241         return(0);
 242 }
 243
 244 static int
 245 donice(struct proc *chgp, int n)
 246 {
 247         struct proc *curp = curproc;
 248         struct ucred *cr = curp->p_ucred;
 249         struct lwp *lp;
 250
 251         if (cr->cr_uid && cr->cr_ruid &&
 252             cr->cr_uid != chgp->p_ucred->cr_uid &&
 253             cr->cr_ruid != chgp->p_ucred->cr_uid)
 254                 return (EPERM);
 255         if (n > PRIO_MAX)
 256                 n = PRIO_MAX;
 257         if (n < PRIO_MIN)
 258                 n = PRIO_MIN;
 259         if (n < chgp->p_nice && priv_check_cred(cr, PRIV_SCHED_SETPRIORITY, 0))
 260                 return (EACCES);
 261         chgp->p_nice = n;
 262         FOREACH_LWP_IN_PROC(lp, chgp)
 263                 chgp->p_usched->resetpriority(lp);
 264         return (0);
 265 }
 266
 267 int
 268 sys_lwp_rtprio(struct lwp_rtprio_args *uap)
 269 {
 270         struct proc *p = curproc;
 271         struct lwp *lp;
 272         struct rtprio rtp;
 273         struct ucred *cr = p->p_ucred;
 274         int error;
 275
 276         error = copyin(uap->rtp, &rtp, sizeof(struct rtprio));
 277         if (error)
 278                 return error;
 279
 280         if (uap->pid < 0) {
 281                 return EINVAL;
 282         } else if (uap->pid == 0) {
 283                 /* curproc already loaded on p */
 284         } else {
 285                 p = pfind(uap->pid);
 286         }
 287
 288         if (p == 0) {
 289                 return ESRCH;
 290         }
 291
 292         if (uap->tid < -1) {
 293                 return EINVAL;
 294         } else if (uap->tid == -1) {
 295                 /*
 296                  * sadly, tid can be 0 so we can't use 0 here
 297                  * like sys_rtprio()
 298                  */
 299                 lp = curthread->td_lwp;
 300         } else {
 301                 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, uap->tid);
 302                 if (lp == NULL)
 303                         return ESRCH;
 304         }
 305
 306         switch (uap->function) {
 307         case RTP_LOOKUP:
 308                 return (copyout(&lp->lwp_rtprio, uap->rtp,
 309                                 sizeof(struct rtprio)));
 310         case RTP_SET:
 311                 if (cr->cr_uid && cr->cr_ruid &&
 312                     cr->cr_uid != p->p_ucred->cr_uid &&
 313                     cr->cr_ruid != p->p_ucred->cr_uid) {
 314                         return EPERM;
 315                 }
 316                 /* disallow setting rtprio in most cases if not superuser */
 317                 if (priv_check_cred(cr, PRIV_SCHED_RTPRIO, 0)) {
 318                         /* can't set someone else's */
 319                         if (uap->pid) { /* XXX */
 320                                 return EPERM;
 321                         }
 322                         /* can't set realtime priority */
 323 /*
 324  * Realtime priority has to be restricted for reasons which should be
 325  * obvious. However, for idle priority, there is a potential for
 326  * system deadlock if an idleprio process gains a lock on a resource
 327  * that other processes need (and the idleprio process can't run
 328  * due to a CPU-bound normal process). Fix me! XXX
 329  */
 330                         if (RTP_PRIO_IS_REALTIME(rtp.type)) {
 331                                 return EPERM;
 332                         }
 333                 }
 334                 switch (rtp.type) {
 335 #ifdef RTP_PRIO_FIFO
 336                 case RTP_PRIO_FIFO:
 337 #endif
 338                 case RTP_PRIO_REALTIME:
 339                 case RTP_PRIO_NORMAL:
 340                 case RTP_PRIO_IDLE:
 341                         if (rtp.prio > RTP_PRIO_MAX)
 342                                 return EINVAL;
 343                         lp->lwp_rtprio = rtp;
 344                         return 0;
 345                 default:
 346                         return EINVAL;
 347                 }
 348         default:
 349                 return EINVAL;
 350         }
 351         panic("can't get here");
 352 }
 353
 354 /*
 355  * Set realtime priority
 356  */
 357 /* ARGSUSED */
 358 int
 359 sys_rtprio(struct rtprio_args *uap)
 360 {
 361         struct proc *curp = curproc;
 362         struct proc *p;
 363         struct lwp *lp;
 364         struct ucred *cr = curp->p_ucred;
 365         struct rtprio rtp;
 366         int error;
 367
 368         error = copyin(uap->rtp, &rtp, sizeof(struct rtprio));
 369         if (error)
 370                 return (error);
 371
 372         if (uap->pid == 0)
 373                 p = curp;
 374         else
 375                 p = pfind(uap->pid);
 376
 377         if (p == 0)
 378                 return (ESRCH);
 379
 380         /* XXX lwp */
 381         lp = FIRST_LWP_IN_PROC(p);
 382         switch (uap->function) {
 383         case RTP_LOOKUP:
 384                 return (copyout(&lp->lwp_rtprio, uap->rtp, sizeof(struct rtprio)));
 385         case RTP_SET:
 386                 if (cr->cr_uid && cr->cr_ruid &&
 387                     cr->cr_uid != p->p_ucred->cr_uid &&
 388                     cr->cr_ruid != p->p_ucred->cr_uid)
 389                         return (EPERM);
 390                 /* disallow setting rtprio in most cases if not superuser */
 391                 if (priv_check_cred(cr, PRIV_SCHED_RTPRIO, 0)) {
 392                         /* can't set someone else's */
 393                         if (uap->pid)
 394                                 return (EPERM);
 395                         /* can't set realtime priority */
 396 /*
 397  * Realtime priority has to be restricted for reasons which should be
 398  * obvious. However, for idle priority, there is a potential for
 399  * system deadlock if an idleprio process gains a lock on a resource
 400  * that other processes need (and the idleprio process can't run
 401  * due to a CPU-bound normal process). Fix me! XXX
 402  */
 403                         if (RTP_PRIO_IS_REALTIME(rtp.type))
 404                                 return (EPERM);
 405                 }
 406                 switch (rtp.type) {
 407 #ifdef RTP_PRIO_FIFO
 408                 case RTP_PRIO_FIFO:
 409 #endif
 410                 case RTP_PRIO_REALTIME:
 411                 case RTP_PRIO_NORMAL:
 412                 case RTP_PRIO_IDLE:
 413                         if (rtp.prio > RTP_PRIO_MAX)
 414                                 return (EINVAL);
 415                         lp->lwp_rtprio = rtp;
 416                         return (0);
 417                 default:
 418                         return (EINVAL);
 419                 }
 420
 421         default:
 422                 return (EINVAL);
 423         }
 424 }
 425
 426 int
 427 sys_setrlimit(struct __setrlimit_args *uap)
 428 {
 429         struct rlimit alim;
 430         int error;
 431
 432         error = copyin(uap->rlp, &alim, sizeof(alim));
 433         if (error)
 434                 return (error);
 435
 436         error = kern_setrlimit(uap->which, &alim);
 437
 438         return (error);
 439 }
 440
 441 int
 442 sys_getrlimit(struct __getrlimit_args *uap)
 443 {
 444         struct rlimit lim;
 445         int error;
 446
 447         error = kern_getrlimit(uap->which, &lim);
 448
 449         if (error == 0)
 450                 error = copyout(&lim, uap->rlp, sizeof(*uap->rlp));
 451         return error;
 452 }
 453
 454 /*
 455  * Transform the running time and tick information in lwp lp's thread into user,
 456  * system, and interrupt time usage.
 457  *
 458  * Since we are limited to statclock tick granularity this is a statisical
 459  * calculation which will be correct over the long haul, but should not be
 460  * expected to measure fine grained deltas.
 461  *
 462  * It is possible to catch a lwp in the midst of being created, so
 463  * check whether lwp_thread is NULL or not.
 464  */
 465 void
 466 calcru(struct lwp *lp, struct timeval *up, struct timeval *sp)
 467 {
 468         struct thread *td;
 469
 470         /*
 471          * Calculate at the statclock level.  YYY if the thread is owned by
 472          * another cpu we need to forward the request to the other cpu, or
 473          * have a token to interlock the information in order to avoid racing
 474          * thread destruction.
 475          */
 476         if ((td = lp->lwp_thread) != NULL) {
 477                 crit_enter();
 478                 up->tv_sec = td->td_uticks / 1000000;
 479                 up->tv_usec = td->td_uticks % 1000000;
 480                 sp->tv_sec = td->td_sticks / 1000000;
 481                 sp->tv_usec = td->td_sticks % 1000000;
 482                 crit_exit();
 483         }
 484 }
 485
 486 /*
 487  * Aggregate resource statistics of all lwps of a process.
 488  *
 489  * proc.p_ru keeps track of all statistics directly related to a proc.  This
 490  * consists of RSS usage and nswap information and aggregate numbers for all
 491  * former lwps of this proc.
 492  *
 493  * proc.p_cru is the sum of all stats of reaped children.
 494  *
 495  * lwp.lwp_ru contains the stats directly related to one specific lwp, meaning
 496  * packet, scheduler switch or page fault counts, etc.  This information gets
 497  * added to lwp.lwp_proc.p_ru when the lwp exits.
 498  */
 499 void
 500 calcru_proc(struct proc *p, struct rusage *ru)
 501 {
 502         struct timeval upt, spt;
 503         long *rip1, *rip2;
 504         struct lwp *lp;
 505
 506         *ru = p->p_ru;
 507
 508         FOREACH_LWP_IN_PROC(lp, p) {
 509                 calcru(lp, &upt, &spt);
 510                 timevaladd(&ru->ru_utime, &upt);
 511                 timevaladd(&ru->ru_stime, &spt);
 512                 for (rip1 = &ru->ru_first, rip2 = &lp->lwp_ru.ru_first;
 513                      rip1 <= &ru->ru_last;
 514                      rip1++, rip2++)
 515                         *rip1 += *rip2;
 516         }
 517 }
 518
 519
 520 /* ARGSUSED */
 521 int
 522 sys_getrusage(struct getrusage_args *uap)
 523 {
 524         struct rusage ru;
 525         struct rusage *rup;
 526
 527         switch (uap->who) {
 528
 529         case RUSAGE_SELF:
 530                 rup = &ru;
 531                 calcru_proc(curproc, rup);
 532                 break;
 533
 534         case RUSAGE_CHILDREN:
 535                 rup = &curproc->p_cru;
 536                 break;
 537
 538         default:
 539                 return (EINVAL);
 540         }
 541         return (copyout((caddr_t)rup, (caddr_t)uap->rusage,
 542             sizeof (struct rusage)));
 543 }
 544
 545 void
 546 ruadd(struct rusage *ru, struct rusage *ru2)
 547 {
 548         long *ip, *ip2;
 549         int i;
 550
 551         timevaladd(&ru->ru_utime, &ru2->ru_utime);
 552         timevaladd(&ru->ru_stime, &ru2->ru_stime);
 553         if (ru->ru_maxrss < ru2->ru_maxrss)
 554                 ru->ru_maxrss = ru2->ru_maxrss;
 555         ip = &ru->ru_first; ip2 = &ru2->ru_first;
 556         for (i = &ru->ru_last - &ru->ru_first; i >= 0; i--)
 557                 *ip++ += *ip2++;
 558 }
 559
 560 /*
 561  * Find the uidinfo structure for a uid.  This structure is used to
 562  * track the total resource consumption (process count, socket buffer
 563  * size, etc.) for the uid and impose limits.
 564  */
 565 void
 566 uihashinit(void)
 567 {
 568         spin_init(&uihash_lock);
 569         uihashtbl = hashinit(maxproc / 16, M_UIDINFO, &uihash);
 570 }
 571
 572 static struct uidinfo *
 573 uilookup(uid_t uid)
 574 {
 575         struct  uihashhead *uipp;
 576         struct  uidinfo *uip;
 577
 578         uipp = UIHASH(uid);
 579         LIST_FOREACH(uip, uipp, ui_hash) {
 580                 if (uip->ui_uid == uid)
 581                         break;
 582         }
 583         return (uip);
 584 }
 585
 586 static struct uidinfo *
 587 uicreate(uid_t uid)
 588 {
 589         struct  uidinfo *uip, *tmp;
 590         /*
 591          * Allocate space and check for a race
 592          */
 593         MALLOC(uip, struct uidinfo *, sizeof(*uip), M_UIDINFO, M_WAITOK);
 594         /*
 595          * Initialize structure and enter it into the hash table
 596          */
 597         spin_init(&uip->ui_lock);
 598         uip->ui_uid = uid;
 599         uip->ui_proccnt = 0;
 600         uip->ui_sbsize = 0;
 601         uip->ui_ref = 1;        /* we're returning a ref */
 602         uip->ui_posixlocks = 0;
 603         varsymset_init(&uip->ui_varsymset, NULL);
 604
 605         /*
 606          * Somebody may have already created the uidinfo for this
 607          * uid. If so, return that instead.
 608          */
 609         spin_lock_wr(&uihash_lock);
 610         tmp = uilookup(uid);
 611         if (tmp != NULL) {
 612                 varsymset_clean(&uip->ui_varsymset);
 613                 spin_uninit(&uip->ui_lock);
 614                 FREE(uip, M_UIDINFO);
 615                 uip = tmp;
 616         } else {
 617                 LIST_INSERT_HEAD(UIHASH(uid), uip, ui_hash);
 618         }
 619         spin_unlock_wr(&uihash_lock);
 620
 621         return (uip);
 622 }
 623
 624 struct uidinfo *
 625 uifind(uid_t uid)
 626 {
 627         struct  uidinfo *uip;
 628
 629         spin_lock_rd(&uihash_lock);
 630         uip = uilookup(uid);
 631         if (uip == NULL) {
 632                 spin_unlock_rd(&uihash_lock);
 633                 uip = uicreate(uid);
 634         } else {
 635                 uihold(uip);
 636                 spin_unlock_rd(&uihash_lock);
 637         }
 638         return (uip);
 639 }
 640
 641 static __inline void
 642 uifree(struct uidinfo *uip)
 643 {
 644         spin_lock_wr(&uihash_lock);
 645
 646         /*
 647          * Note that we're taking a read lock even though we
 648          * modify the structure because we know nobody can find
 649          * it now that we've locked uihash_lock. If somebody
 650          * can get to it through a stored pointer, the reference
 651          * count will not be 0 and in that case we don't modify
 652          * the struct.
 653          */
 654         spin_lock_rd(&uip->ui_lock);
 655         if (uip->ui_ref != 0) {
 656                 /*
 657                  * Someone found the uid and got a ref when we
 658                  * unlocked. No need to free any more.
 659                  */
 660                 spin_unlock_rd(&uip->ui_lock);
 661                 return;
 662         }
 663         if (uip->ui_sbsize != 0)
 664                 /* XXX no %qd in kernel.  Truncate. */
 665                 kprintf("freeing uidinfo: uid = %d, sbsize = %ld\n",
 666                     uip->ui_uid, (long)uip->ui_sbsize);
 667         if (uip->ui_proccnt != 0)
 668                 kprintf("freeing uidinfo: uid = %d, proccnt = %ld\n",
 669                     uip->ui_uid, uip->ui_proccnt);
 670
 671         LIST_REMOVE(uip, ui_hash);
 672         spin_unlock_wr(&uihash_lock);
 673         varsymset_clean(&uip->ui_varsymset);
 674         lockuninit(&uip->ui_varsymset.vx_lock);
 675         spin_unlock_rd(&uip->ui_lock);
 676         spin_uninit(&uip->ui_lock);
 677         FREE(uip, M_UIDINFO);
 678 }
 679
 680 void
 681 uihold(struct uidinfo *uip)
 682 {
 683         atomic_add_int(&uip->ui_ref, 1);
 684         KKASSERT(uip->ui_ref > 0);
 685 }
 686
 687 void
 688 uidrop(struct uidinfo *uip)
 689 {
 690         if (atomic_fetchadd_int(&uip->ui_ref, -1) == 1) {
 691                 uifree(uip);
 692         } else {
 693                 KKASSERT(uip->ui_ref > 0);
 694         }
 695 }
 696
 697 void
 698 uireplace(struct uidinfo **puip, struct uidinfo *nuip)
 699 {
 700         uidrop(*puip);
 701         *puip = nuip;
 702 }
 703
 704 /*
 705  * Change the count associated with number of processes
 706  * a given user is using.  When 'max' is 0, don't enforce a limit
 707  */
 708 int
 709 chgproccnt(struct uidinfo *uip, int diff, int max)
 710 {
 711         int ret;
 712         spin_lock_wr(&uip->ui_lock);
 713         /* don't allow them to exceed max, but allow subtraction */
 714         if (diff > 0 && uip->ui_proccnt + diff > max && max != 0) {
 715                 ret = 0;
 716         } else {
 717                 uip->ui_proccnt += diff;
 718                 if (uip->ui_proccnt < 0)
 719                         kprintf("negative proccnt for uid = %d\n", uip->ui_uid);
 720                 ret = 1;
 721         }
 722         spin_unlock_wr(&uip->ui_lock);
 723         return ret;
 724 }
 725
 726 /*
 727  * Change the total socket buffer size a user has used.
 728  */
 729 int
 730 chgsbsize(struct uidinfo *uip, u_long *hiwat, u_long to, rlim_t max)
 731 {
 732         rlim_t new;
 733
 734         spin_lock_wr(&uip->ui_lock);
 735         new = uip->ui_sbsize + to - *hiwat;
 736         KKASSERT(new >= 0);
 737
 738         /*
 739          * If we are trying to increase the socket buffer size
 740          * Scale down the hi water mark when we exceed the user's
 741          * allowed socket buffer space.
 742          *
 743          * We can't scale down too much or we will blow up atomic packet
 744          * operations.
 745          */
 746         if (to > *hiwat && to > MCLBYTES && new > max) {
 747                 to = to * max / new;
 748                 if (to < MCLBYTES)
 749                         to = MCLBYTES;
 750         }
 751         uip->ui_sbsize = new;
 752         *hiwat = to;
 753         spin_unlock_wr(&uip->ui_lock);
 754         return (1);
 755 }
 756