1 /* 2 * Copyright (c) 2006 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 /* 35 * Copyright (c) 1982, 1986, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)kern_resource.c 8.5 (Berkeley) 1/21/94 68 * $FreeBSD: src/sys/kern/kern_resource.c,v 1.55.2.5 2001/11/03 01:41:08 ps Exp $ 69 * $DragonFly: src/sys/kern/kern_plimit.c,v 1.3 2008/05/08 01:26:00 dillon Exp $ 70 */ 71 72 #include <sys/resource.h> 73 #include <sys/spinlock.h> 74 #include <sys/proc.h> 75 #include <sys/priv.h> 76 #include <sys/file.h> 77 #include <sys/lockf.h> 78 #include <sys/kern_syscall.h> 79 80 #include <vm/vm_param.h> 81 #include <vm/vm.h> 82 #include <vm/vm_map.h> 83 84 #include <machine/pmap.h> 85 86 #include <sys/spinlock2.h> 87 88 static void plimit_copy(struct plimit *olimit, struct plimit *nlimit); 89 90 /* 91 * Initialize proc0's plimit structure. All later plimit structures 92 * are inherited through fork. 93 */ 94 void 95 plimit_init0(struct plimit *limit) 96 { 97 int i; 98 rlim_t lim; 99 100 for (i = 0; i < RLIM_NLIMITS; ++i) { 101 limit->pl_rlimit[i].rlim_cur = RLIM_INFINITY; 102 limit->pl_rlimit[i].rlim_max = RLIM_INFINITY; 103 } 104 limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur = maxfiles; 105 limit->pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles; 106 limit->pl_rlimit[RLIMIT_NPROC].rlim_cur = maxproc; 107 limit->pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc; 108 lim = ptoa((rlim_t)vmstats.v_free_count); 109 limit->pl_rlimit[RLIMIT_RSS].rlim_max = lim; 110 limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim; 111 limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3; 112 limit->p_cpulimit = RLIM_INFINITY; 113 limit->p_refcnt = 1; 114 spin_init(&limit->p_spin); 115 } 116 117 /* 118 * Return a plimit for use by a new forked process given the one 119 * contained in the parent process. 120 * 121 * MPSAFE 122 */ 123 struct plimit * 124 plimit_fork(struct proc *p1) 125 { 126 struct plimit *olimit = p1->p_limit; 127 struct plimit *nlimit = NULL; 128 struct plimit *rlimit; 129 130 /* 131 * If we are exclusive (but not threaded-exclusive), but have only 132 * one reference, we can convert the structure to copy-on-write 133 * again. 134 * 135 * If we were threaded but are no longer threaded we can do the same 136 * thing. 137 */ 138 if (olimit->p_exclusive == 1) { 139 KKASSERT(olimit->p_refcnt == 1); 140 olimit->p_exclusive = 0; 141 } else if (olimit->p_exclusive == 2 && p1->p_nthreads == 1) { 142 KKASSERT(olimit->p_refcnt == 1); 143 olimit->p_exclusive = 0; 144 } 145 146 /* 147 * Take a short-cut that requires limited spin locks. If we aren't 148 * exclusive we will not be threaded and we can just bump the ref 149 * count. If that is true and we also have only one ref then there 150 * can be no other accessors. 151 */ 152 if (olimit->p_exclusive == 0) { 153 if (olimit->p_refcnt == 1) { 154 ++olimit->p_refcnt; 155 } else { 156 spin_lock_wr(&olimit->p_spin); 157 ++olimit->p_refcnt; 158 spin_unlock_wr(&olimit->p_spin); 159 } 160 return(olimit); 161 } 162 163 /* 164 * Full-blown code-up. 165 */ 166 nlimit = NULL; 167 spin_lock_wr(&olimit->p_spin); 168 169 for (;;) { 170 if (olimit->p_exclusive == 0) { 171 ++olimit->p_refcnt; 172 rlimit = olimit; 173 break; 174 } 175 if (nlimit) { 176 plimit_copy(olimit, nlimit); 177 rlimit = nlimit; 178 nlimit = NULL; 179 break; 180 } 181 spin_unlock_wr(&olimit->p_spin); 182 nlimit = kmalloc(sizeof(*nlimit), M_SUBPROC, M_WAITOK); 183 spin_lock_wr(&olimit->p_spin); 184 } 185 spin_unlock_wr(&olimit->p_spin); 186 if (nlimit) 187 kfree(nlimit, M_SUBPROC); 188 return(rlimit); 189 } 190 191 /* 192 * This routine is called when a new LWP is created for a process. We 193 * must force exclusivity (=2) so p->p_limit remains stable. 194 * 195 * LWPs share the same process structure so this does not bump refcnt. 196 */ 197 void 198 plimit_lwp_fork(struct proc *p) 199 { 200 struct plimit *olimit; 201 202 for (;;) { 203 olimit = p->p_limit; 204 if (olimit->p_exclusive == 2) { 205 KKASSERT(olimit->p_refcnt == 1); 206 break; 207 } 208 if (olimit->p_refcnt == 1) { 209 olimit->p_exclusive = 2; 210 break; 211 } 212 plimit_modify(p, -1, NULL); 213 } 214 } 215 216 /* 217 * This routine is called to fixup a proces's p_limit structure prior 218 * to it being modified. If index >= 0 the specified modification is also 219 * made. 220 * 221 * This routine must make the limit structure exclusive. A later fork 222 * will convert it back to copy-on-write if possible. 223 * 224 * We can count on p->p_limit being stable since if we had created any 225 * threads it will have already been made exclusive (=2). 226 * 227 * MPSAFE 228 */ 229 void 230 plimit_modify(struct proc *p, int index, struct rlimit *rlim) 231 { 232 struct plimit *olimit; 233 struct plimit *nlimit; 234 struct plimit *rlimit; 235 236 /* 237 * Shortcut. If we are not threaded we may be able to trivially 238 * set the structure to exclusive access without needing to acquire 239 * any spinlocks. The p_limit structure will be stable. 240 */ 241 olimit = p->p_limit; 242 if (p->p_nthreads == 1) { 243 if (olimit->p_exclusive == 0 && olimit->p_refcnt == 1) 244 olimit->p_exclusive = 1; 245 if (olimit->p_exclusive) { 246 if (index >= 0) 247 p->p_limit->pl_rlimit[index] = *rlim; 248 return; 249 } 250 } 251 252 /* 253 * Full-blown code-up. Make a copy if we aren't exclusive. If 254 * we have only one ref we can safely convert the structure to 255 * exclusive without copying. 256 */ 257 nlimit = NULL; 258 spin_lock_wr(&olimit->p_spin); 259 260 for (;;) { 261 if (olimit->p_refcnt == 1) { 262 if (olimit->p_exclusive == 0) 263 olimit->p_exclusive = 1; 264 rlimit = olimit; 265 break; 266 } 267 KKASSERT(olimit->p_exclusive == 0); 268 if (nlimit) { 269 plimit_copy(olimit, nlimit); 270 nlimit->p_exclusive = 1; 271 p->p_limit = nlimit; 272 rlimit = nlimit; 273 nlimit = NULL; 274 break; 275 } 276 spin_unlock_wr(&olimit->p_spin); 277 nlimit = kmalloc(sizeof(*nlimit), M_SUBPROC, M_WAITOK); 278 spin_lock_wr(&olimit->p_spin); 279 } 280 if (index >= 0) 281 rlimit->pl_rlimit[index] = *rlim; 282 spin_unlock_wr(&olimit->p_spin); 283 if (nlimit) 284 kfree(nlimit, M_SUBPROC); 285 } 286 287 /* 288 * Destroy a process's plimit structure. 289 * 290 * MPSAFE 291 */ 292 void 293 plimit_free(struct proc *p) 294 { 295 struct plimit *limit; 296 297 if ((limit = p->p_limit) != NULL) { 298 p->p_limit = NULL; 299 300 if (limit->p_refcnt == 1) { 301 limit->p_refcnt = -999; 302 kfree(limit, M_SUBPROC); 303 } else { 304 spin_lock_wr(&limit->p_spin); 305 if (--limit->p_refcnt == 0) { 306 spin_unlock_wr(&limit->p_spin); 307 kfree(limit, M_SUBPROC); 308 } else { 309 spin_unlock_wr(&limit->p_spin); 310 } 311 } 312 } 313 } 314 315 /* 316 * Modify a resource limit (from system call) 317 * 318 * MPSAFE 319 */ 320 int 321 kern_setrlimit(u_int which, struct rlimit *limp) 322 { 323 struct proc *p = curproc; 324 struct plimit *limit; 325 struct rlimit *alimp; 326 int error; 327 328 if (which >= RLIM_NLIMITS) 329 return (EINVAL); 330 331 /* 332 * We will be modifying a resource, make a copy if necessary. 333 */ 334 plimit_modify(p, -1, NULL); 335 limit = p->p_limit; 336 alimp = &limit->pl_rlimit[which]; 337 338 /* 339 * Preserve historical bugs by treating negative limits as unsigned. 340 */ 341 if (limp->rlim_cur < 0) 342 limp->rlim_cur = RLIM_INFINITY; 343 if (limp->rlim_max < 0) 344 limp->rlim_max = RLIM_INFINITY; 345 346 spin_lock_rd(&limit->p_spin); 347 if (limp->rlim_cur > alimp->rlim_max || 348 limp->rlim_max > alimp->rlim_max) { 349 spin_unlock_rd(&limit->p_spin); 350 if ((error = priv_check_cred(p->p_ucred, PRIV_ROOT, PRISON_ROOT))) 351 return (error); 352 } else { 353 spin_unlock_rd(&limit->p_spin); 354 } 355 if (limp->rlim_cur > limp->rlim_max) 356 limp->rlim_cur = limp->rlim_max; 357 358 switch (which) { 359 case RLIMIT_CPU: 360 spin_lock_wr(&limit->p_spin); 361 if (limp->rlim_cur > RLIM_INFINITY / (rlim_t)1000000) 362 limit->p_cpulimit = RLIM_INFINITY; 363 else 364 limit->p_cpulimit = (rlim_t)1000000 * limp->rlim_cur; 365 spin_unlock_wr(&limit->p_spin); 366 break; 367 case RLIMIT_DATA: 368 if (limp->rlim_cur > maxdsiz) 369 limp->rlim_cur = maxdsiz; 370 if (limp->rlim_max > maxdsiz) 371 limp->rlim_max = maxdsiz; 372 break; 373 374 case RLIMIT_STACK: 375 if (limp->rlim_cur > maxssiz) 376 limp->rlim_cur = maxssiz; 377 if (limp->rlim_max > maxssiz) 378 limp->rlim_max = maxssiz; 379 /* 380 * Stack is allocated to the max at exec time with only 381 * "rlim_cur" bytes accessible. If stack limit is going 382 * up make more accessible, if going down make inaccessible. 383 */ 384 spin_lock_rd(&limit->p_spin); 385 if (limp->rlim_cur != alimp->rlim_cur) { 386 vm_offset_t addr; 387 vm_size_t size; 388 vm_prot_t prot; 389 390 if (limp->rlim_cur > alimp->rlim_cur) { 391 prot = VM_PROT_ALL; 392 size = limp->rlim_cur - alimp->rlim_cur; 393 addr = USRSTACK - limp->rlim_cur; 394 } else { 395 prot = VM_PROT_NONE; 396 size = alimp->rlim_cur - limp->rlim_cur; 397 addr = USRSTACK - alimp->rlim_cur; 398 } 399 spin_unlock_rd(&limit->p_spin); 400 addr = trunc_page(addr); 401 size = round_page(size); 402 (void) vm_map_protect(&p->p_vmspace->vm_map, 403 addr, addr+size, prot, FALSE); 404 } else { 405 spin_unlock_rd(&limit->p_spin); 406 } 407 break; 408 409 case RLIMIT_NOFILE: 410 if (limp->rlim_cur > maxfilesperproc) 411 limp->rlim_cur = maxfilesperproc; 412 if (limp->rlim_max > maxfilesperproc) 413 limp->rlim_max = maxfilesperproc; 414 break; 415 416 case RLIMIT_NPROC: 417 if (limp->rlim_cur > maxprocperuid) 418 limp->rlim_cur = maxprocperuid; 419 if (limp->rlim_max > maxprocperuid) 420 limp->rlim_max = maxprocperuid; 421 if (limp->rlim_cur < 1) 422 limp->rlim_cur = 1; 423 if (limp->rlim_max < 1) 424 limp->rlim_max = 1; 425 break; 426 case RLIMIT_POSIXLOCKS: 427 if (limp->rlim_cur > maxposixlocksperuid) 428 limp->rlim_cur = maxposixlocksperuid; 429 if (limp->rlim_max > maxposixlocksperuid) 430 limp->rlim_max = maxposixlocksperuid; 431 break; 432 } 433 spin_lock_wr(&limit->p_spin); 434 *alimp = *limp; 435 spin_unlock_wr(&limit->p_spin); 436 return (0); 437 } 438 439 /* 440 * The rlimit indexed by which is returned in the second argument. 441 * 442 * MPSAFE 443 */ 444 int 445 kern_getrlimit(u_int which, struct rlimit *limp) 446 { 447 struct proc *p = curproc; 448 struct plimit *limit; 449 450 if (which >= RLIM_NLIMITS) 451 return (EINVAL); 452 453 limit = p->p_limit; 454 spin_lock_rd(&limit->p_spin); 455 *limp = p->p_rlimit[which]; 456 spin_unlock_rd(&limit->p_spin); 457 return (0); 458 } 459 460 /* 461 * Determine if the cpu limit has been reached and return an operations 462 * code for the caller to perform. 463 * 464 * MPSAFE 465 */ 466 int 467 plimit_testcpulimit(struct plimit *limit, u_int64_t ttime) 468 { 469 struct rlimit *rlim; 470 int mode; 471 472 mode = PLIMIT_TESTCPU_OK; 473 if (limit->p_cpulimit != RLIM_INFINITY) { 474 spin_lock_rd(&limit->p_spin); 475 if (ttime > limit->p_cpulimit) { 476 rlim = &limit->pl_rlimit[RLIMIT_CPU]; 477 if (ttime / (rlim_t)1000000 >= rlim->rlim_max + 5) { 478 mode = PLIMIT_TESTCPU_KILL; 479 } else { 480 mode = PLIMIT_TESTCPU_XCPU; 481 } 482 } 483 spin_unlock_rd(&limit->p_spin); 484 } 485 return(mode); 486 } 487 488 /* 489 * Helper routine to copy olimit to nlimit and initialize nlimit for 490 * use. nlimit's reference count will be set to 1 and its exclusive bit 491 * will be cleared. 492 * 493 * MPSAFE 494 */ 495 static 496 void 497 plimit_copy(struct plimit *olimit, struct plimit *nlimit) 498 { 499 *nlimit = *olimit; 500 501 spin_init(&nlimit->p_spin); 502 nlimit->p_refcnt = 1; 503 nlimit->p_exclusive = 0; 504 } 505 506