kernel/syscall/rlimit.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  28 /*        All Rights Reserved   */
  29
  30
  31 #include <sys/param.h>
  32 #include <sys/types.h>
  33 #include <sys/inttypes.h>
  34 #include <sys/sysmacros.h>
  35 #include <sys/systm.h>
  36 #include <sys/tuneable.h>
  37 #include <sys/user.h>
  38 #include <sys/errno.h>
  39 #include <sys/vnode.h>
  40 #include <sys/file.h>
  41 #include <sys/proc.h>
  42 #include <sys/resource.h>
  43 #include <sys/ulimit.h>
  44 #include <sys/debug.h>
  45 #include <sys/rctl.h>
  46
  47 #include <vm/as.h>
  48
  49 /*
  50  * Perhaps ulimit could be moved into a user library, as calls to
  51  * getrlimit and setrlimit, were it not for binary compatibility
  52  * restrictions.
  53  */
  54 long
  55 ulimit(int cmd, long arg)
  56 {
  57         proc_t *p = curproc;
  58         long    retval;
  59
  60         switch (cmd) {
  61
  62         case UL_GFILLIM: /* Return current file size limit. */
  63         {
  64                 rlim64_t filesize;
  65
  66                 mutex_enter(&p->p_lock);
  67                 filesize = rctl_enforced_value(rctlproc_legacy[RLIMIT_FSIZE],
  68                     p->p_rctls, p);
  69                 mutex_exit(&p->p_lock);
  70
  71                 if (get_udatamodel() == DATAMODEL_ILP32) {
  72                         /*
  73                          * File size is returned in blocks for ulimit.
  74                          * This function is deprecated and therefore LFS API
  75                          * didn't define the behaviour of ulimit.
  76                          * Here we return maximum value of file size possible
  77                          * so that applications that do not check errors
  78                          * continue to work.
  79                          */
  80                         if (filesize > MAXOFF32_T)
  81                                 filesize = MAXOFF32_T;
  82                         retval = ((int)filesize >> SCTRSHFT);
  83                 } else
  84                         retval = filesize >> SCTRSHFT;
  85                 break;
  86         }
  87
  88         case UL_SFILLIM: /* Set new file size limit. */
  89         {
  90                 int error = 0;
  91                 rlim64_t lim = (rlim64_t)arg;
  92                 struct rlimit64 rl64;
  93                 rctl_alloc_gp_t *gp = rctl_rlimit_set_prealloc(1);
  94
  95                 if (lim >= (((rlim64_t)MAXOFFSET_T) >> SCTRSHFT))
  96                         lim = (rlim64_t)RLIM64_INFINITY;
  97                 else
  98                         lim <<= SCTRSHFT;
  99
 100                 rl64.rlim_max = rl64.rlim_cur = lim;
 101                 mutex_enter(&p->p_lock);
 102                 if (error = rctl_rlimit_set(rctlproc_legacy[RLIMIT_FSIZE], p,
 103                     &rl64, gp, RCTL_LOCAL_DENY | RCTL_LOCAL_SIGNAL, SIGXFSZ,
 104                     CRED())) {
 105                         mutex_exit(&p->p_lock);
 106                         rctl_prealloc_destroy(gp);
 107                         return (set_errno(error));
 108                 }
 109                 mutex_exit(&p->p_lock);
 110                 rctl_prealloc_destroy(gp);
 111                 retval = arg;
 112                 break;
 113         }
 114
 115         case UL_GMEMLIM: /* Return maximum possible break value. */
 116         {
 117                 struct seg *seg;
 118                 struct seg *nextseg;
 119                 struct as *as = p->p_as;
 120                 caddr_t brkend;
 121                 caddr_t brkbase;
 122                 size_t size;
 123                 rlim64_t size_ctl;
 124                 rlim64_t vmem_ctl;
 125
 126                 /*
 127                  * Find the segment with a virtual address
 128                  * greater than the end of the current break.
 129                  */
 130                 nextseg = NULL;
 131                 mutex_enter(&p->p_lock);
 132                 brkbase = (caddr_t)p->p_brkbase;
 133                 brkend = (caddr_t)p->p_brkbase + p->p_brksize;
 134                 mutex_exit(&p->p_lock);
 135
 136                 /*
 137                  * Since we can't return less than the current break,
 138                  * initialize the return value to the current break
 139                  */
 140                 retval = (long)brkend;
 141
 142                 AS_LOCK_ENTER(as, RW_READER);
 143                 for (seg = as_findseg(as, brkend, 0); seg != NULL;
 144                     seg = AS_SEGNEXT(as, seg)) {
 145                         if (seg->s_base >= brkend) {
 146                                 nextseg = seg;
 147                                 break;
 148                         }
 149                 }
 150
 151                 mutex_enter(&p->p_lock);
 152                 size_ctl = rctl_enforced_value(rctlproc_legacy[RLIMIT_DATA],
 153                     p->p_rctls, p);
 154                 vmem_ctl = rctl_enforced_value(rctlproc_legacy[RLIMIT_VMEM],
 155                     p->p_rctls, p);
 156                 mutex_exit(&p->p_lock);
 157
 158                 /*
 159                  * First, calculate the maximum break value based on
 160                  * the user's RLIMIT_DATA, but also taking into account
 161                  * that this value cannot be greater than as->a_userlimit.
 162                  * We also take care to make sure that we don't overflow
 163                  * in the calculation.
 164                  */
 165                 /*
 166                  * Since we are casting the RLIMIT_DATA value to a
 167                  * ulong (a 32-bit value in the 32-bit kernel) we have
 168                  * to pass this assertion.
 169                  */
 170                 ASSERT32((size_t)size_ctl <= UINT32_MAX);
 171
 172                 size = (size_t)size_ctl;
 173                 if (as->a_userlimit - brkbase > size)
 174                         retval = MAX((size_t)retval, (size_t)(brkbase + size));
 175                                         /* don't return less than current */
 176                 else
 177                         retval = (long)as->a_userlimit;
 178
 179                 /*
 180                  * The max break cannot extend into the next segment
 181                  */
 182                 if (nextseg != NULL)
 183                         retval = MIN((uintptr_t)retval,
 184                             (uintptr_t)nextseg->s_base);
 185
 186                 /*
 187                  * Handle the case where there is an limit on RLIMIT_VMEM
 188                  */
 189                 if (vmem_ctl < UINT64_MAX) {
 190                         /* calculate brkend based on the end of page */
 191                         caddr_t brkendpg = (caddr_t)roundup((uintptr_t)brkend,
 192                             PAGESIZE);
 193                         /*
 194                          * Large Files: The following assertion has to pass
 195                          * through to ensure the correctness of the cast.
 196                          */
 197                         ASSERT32(vmem_ctl <= UINT32_MAX);
 198
 199                         size = (size_t)(vmem_ctl & PAGEMASK);
 200
 201                         if (as->a_size < size)
 202                                 size -= as->a_size;
 203                         else
 204                                 size = 0;
 205                         /*
 206                          * Take care to not overflow the calculation
 207                          */
 208                         if (as->a_userlimit - brkendpg > size)
 209                                 retval = MIN((size_t)retval,
 210                                     (size_t)(brkendpg + size));
 211                 }
 212
 213                 AS_LOCK_EXIT(as);
 214
 215                 /* truncate to same boundary as sbrk */
 216
 217                 switch (get_udatamodel()) {
 218                 default:
 219                 case DATAMODEL_ILP32:
 220                         retval = retval & ~(8-1);
 221                         break;
 222                 case DATAMODEL_LP64:
 223                         retval = retval & ~(16-1);
 224                         break;
 225                 }
 226                 break;
 227         }
 228
 229         case UL_GDESLIM: /* Return approximate number of open files */
 230         {
 231                 rlim64_t fdno_ctl;
 232
 233                 mutex_enter(&curproc->p_lock);
 234                 fdno_ctl = rctl_enforced_value(rctlproc_legacy[RLIMIT_NOFILE],
 235                     curproc->p_rctls, curproc);
 236                 ASSERT(fdno_ctl <= INT_MAX);
 237                 retval = (rlim_t)fdno_ctl;
 238                 mutex_exit(&curproc->p_lock);
 239                 break;
 240         }
 241
 242         default:
 243                 return (set_errno(EINVAL));
 244
 245         }
 246         return (retval);
 247 }
 248
 249 #ifdef _SYSCALL32_IMPL
 250
 251 int
 252 ulimit32(int cmd, int arg)
 253 {
 254         return ((int)ulimit(cmd, (long)arg));
 255 }
 256
 257 #endif  /* _SYSCALL32_IMPL */
 258
 259 #if defined(_ILP32) || defined(_SYSCALL32_IMPL)
 260
 261 /*
 262  * Large Files: getrlimit returns RLIM_SAVED_CUR or RLIM_SAVED_MAX when
 263  * rlim_cur or rlim_max is not representable in 32-bit rlim_t. These
 264  * values are just tokens which will be used in setrlimit to set the
 265  * correct limits. The current limits are saved in the saved_rlimit members
 266  * in user structures when the token is returned. setrlimit restores
 267  * the limit values to these saved values when the token is passed.
 268  * Consider the following common scenario of the apps:
 269  *
 270  *              limit = getrlimit();
 271  *              savedlimit = limit;
 272  *              limit = limit1;
 273  *              setrlimit(limit)
 274  *              // execute all processes in the new rlimit state.
 275  *              setrlimit(savedlimit) // restore the old values.
 276  *
 277  * Most apps don't check error returns from getrlimit or setrlimit
 278  * and this is why we return tokens when the correct value
 279  * cannot be represented in rlim_t. For more discussion refer to
 280  * the LFS API document.
 281  *
 282  * In the 64-bit kernel, all existing resource limits are treated in this
 283  * manner.  In the 32-bit kernel, CPU time is treated equivalently to the
 284  * file size limit above; the VM-related limits are not.  The macro,
 285  * RLIM_SAVED(x), returns true if the resource limit should be handled in
 286  * this way on the current kernel.
 287  */
 288 int
 289 getrlimit32(int resource, struct rlimit32 *rlp)
 290 {
 291         struct rlimit32 rlim32;
 292         struct rlimit64 rlim64;
 293         struct proc *p = curproc;
 294         struct user *up = PTOU(p);
 295         int savecur = 0;
 296         int savemax = 0;
 297
 298         if (resource < 0 || resource >= RLIM_NLIMITS)
 299                 return (set_errno(EINVAL));
 300
 301         mutex_enter(&p->p_lock);
 302         (void) rctl_rlimit_get(rctlproc_legacy[resource], p, &rlim64);
 303         mutex_exit(&p->p_lock);
 304
 305         if (rlim64.rlim_max > (rlim64_t)UINT32_MAX) {
 306
 307                 if (rlim64.rlim_max == RLIM64_INFINITY)
 308                         rlim32.rlim_max = RLIM32_INFINITY;
 309                 else {
 310                         savemax = 1;
 311                         rlim32.rlim_max = RLIM32_SAVED_MAX;
 312                         /*CONSTCOND*/
 313                         ASSERT(RLIM_SAVED(resource));
 314                 }
 315
 316                 if (rlim64.rlim_cur == RLIM64_INFINITY)
 317                         rlim32.rlim_cur = RLIM32_INFINITY;
 318                 else if (rlim64.rlim_cur == rlim64.rlim_max) {
 319                         savecur = 1;
 320                         rlim32.rlim_cur = RLIM32_SAVED_MAX;
 321                         /*CONSTCOND*/
 322                         ASSERT(RLIM_SAVED(resource));
 323                 } else if (rlim64.rlim_cur > (rlim64_t)UINT32_MAX) {
 324                         savecur = 1;
 325                         rlim32.rlim_cur = RLIM32_SAVED_CUR;
 326                         /*CONSTCOND*/
 327                         ASSERT(RLIM_SAVED(resource));
 328                 } else
 329                         rlim32.rlim_cur = rlim64.rlim_cur;
 330
 331                 /*
 332                  * save the current limits in user structure.
 333                  */
 334                 /*CONSTCOND*/
 335                 if (RLIM_SAVED(resource)) {
 336                         mutex_enter(&p->p_lock);
 337                         if (savemax)
 338                                 up->u_saved_rlimit[resource].rlim_max =
 339                                     rlim64.rlim_max;
 340                         if (savecur)
 341                                 up->u_saved_rlimit[resource].rlim_cur =
 342                                     rlim64.rlim_cur;
 343                         mutex_exit(&p->p_lock);
 344                 }
 345         } else {
 346                 ASSERT(rlim64.rlim_cur <= (rlim64_t)UINT32_MAX);
 347                 rlim32.rlim_max = rlim64.rlim_max;
 348                 rlim32.rlim_cur = rlim64.rlim_cur;
 349         }
 350
 351         if (copyout(&rlim32, rlp, sizeof (rlim32)))
 352                 return (set_errno(EFAULT));
 353
 354         return (0);
 355 }
 356
 357 /*
 358  * See comments above getrlimit32(). When the tokens are passed in the
 359  * rlimit structure the values are considered equal to the values
 360  * stored in saved_rlimit members of user structure.
 361  * When the user passes RLIM_INFINITY to set the resource limit to
 362  * unlimited internally understand this value as RLIM64_INFINITY and
 363  * let rlimit() do the job.
 364  */
 365 int
 366 setrlimit32(int resource, struct rlimit32 *rlp)
 367 {
 368         struct rlimit32 rlim32;
 369         struct rlimit64 rlim64;
 370         struct rlimit64 saved_rlim;
 371         int     error;
 372         struct proc *p = ttoproc(curthread);
 373         struct user *up = PTOU(p);
 374         rctl_alloc_gp_t *gp;
 375
 376         if (resource < 0 || resource >= RLIM_NLIMITS)
 377                 return (set_errno(EINVAL));
 378         if (copyin(rlp, &rlim32, sizeof (rlim32)))
 379                 return (set_errno(EFAULT));
 380
 381         gp = rctl_rlimit_set_prealloc(1);
 382
 383         /*
 384          * Disallow resource limit tunnelling
 385          */
 386         /*CONSTCOND*/
 387         if (RLIM_SAVED(resource)) {
 388                 mutex_enter(&p->p_lock);
 389                 saved_rlim = up->u_saved_rlimit[resource];
 390                 mutex_exit(&p->p_lock);
 391         } else {
 392                 saved_rlim.rlim_max = (rlim64_t)rlim32.rlim_max;
 393                 saved_rlim.rlim_cur = (rlim64_t)rlim32.rlim_cur;
 394         }
 395
 396         switch (rlim32.rlim_cur) {
 397         case RLIM32_INFINITY:
 398                 rlim64.rlim_cur = RLIM64_INFINITY;
 399                 break;
 400         case RLIM32_SAVED_CUR:
 401                 rlim64.rlim_cur = saved_rlim.rlim_cur;
 402                 break;
 403         case RLIM32_SAVED_MAX:
 404                 rlim64.rlim_cur = saved_rlim.rlim_max;
 405                 break;
 406         default:
 407                 rlim64.rlim_cur = (rlim64_t)rlim32.rlim_cur;
 408                 break;
 409         }
 410
 411         switch (rlim32.rlim_max) {
 412         case RLIM32_INFINITY:
 413                 rlim64.rlim_max = RLIM64_INFINITY;
 414                 break;
 415         case RLIM32_SAVED_MAX:
 416                 rlim64.rlim_max = saved_rlim.rlim_max;
 417                 break;
 418         case RLIM32_SAVED_CUR:
 419                 rlim64.rlim_max = saved_rlim.rlim_cur;
 420                 break;
 421         default:
 422                 rlim64.rlim_max = (rlim64_t)rlim32.rlim_max;
 423                 break;
 424         }
 425
 426         mutex_enter(&p->p_lock);
 427         if (error = rctl_rlimit_set(rctlproc_legacy[resource], p, &rlim64, gp,
 428             rctlproc_flags[resource], rctlproc_signals[resource], CRED())) {
 429                 mutex_exit(&p->p_lock);
 430                 rctl_prealloc_destroy(gp);
 431                 return (set_errno(error));
 432         }
 433         mutex_exit(&p->p_lock);
 434         rctl_prealloc_destroy(gp);
 435
 436         return (0);
 437 }
 438
 439 #endif  /* _ILP32 && _SYSCALL32_IMPL */
 440
 441 int
 442 getrlimit64(int resource, struct rlimit64 *rlp)
 443 {
 444         struct rlimit64 rlim64;
 445         struct proc *p = ttoproc(curthread);
 446
 447         if (resource < 0 || resource >= RLIM_NLIMITS)
 448                 return (set_errno(EINVAL));
 449
 450         mutex_enter(&p->p_lock);
 451         (void) rctl_rlimit_get(rctlproc_legacy[resource], p, &rlim64);
 452         mutex_exit(&p->p_lock);
 453
 454         if (copyout(&rlim64, rlp, sizeof (rlim64)))
 455                 return (set_errno(EFAULT));
 456         return (0);
 457 }
 458
 459 int
 460 setrlimit64(int resource, struct rlimit64 *rlp)
 461 {
 462         struct rlimit64 rlim64;
 463         struct proc *p = ttoproc(curthread);
 464         int     error;
 465         rctl_alloc_gp_t *gp;
 466
 467         if (resource < 0 || resource >= RLIM_NLIMITS)
 468                 return (set_errno(EINVAL));
 469         if (copyin(rlp, &rlim64, sizeof (rlim64)))
 470                 return (set_errno(EFAULT));
 471
 472         gp = rctl_rlimit_set_prealloc(1);
 473
 474         mutex_enter(&p->p_lock);
 475         if (error = rctl_rlimit_set(rctlproc_legacy[resource], p, &rlim64, gp,
 476             rctlproc_flags[resource], rctlproc_signals[resource], CRED())) {
 477                 mutex_exit(&p->p_lock);
 478                 rctl_prealloc_destroy(gp);
 479                 return (set_errno(error));
 480         }
 481         mutex_exit(&p->p_lock);
 482         rctl_prealloc_destroy(gp);
 483         return (0);
 484
 485 }