2 * Copyright (c) 2006 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
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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 $
72 #include <sys/resource.h>
73 #include <sys/spinlock.h>
77 #include <sys/lockf.h>
78 #include <sys/kern_syscall.h>
80 #include <vm/vm_param.h>
82 #include <vm/vm_map.h>
84 #include <machine/pmap.h>
86 #include <sys/spinlock2.h>
88 static void plimit_copy(struct plimit *olimit, struct plimit *nlimit);
91 * Initialize proc0's plimit structure. All later plimit structures
92 * are inherited through fork.
95 plimit_init0(struct plimit *limit)
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;
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;
114 spin_init(&limit->p_spin);
118 * Return a plimit for use by a new forked process given the one
119 * contained in the parent process.
124 plimit_fork(struct proc *p1)
126 struct plimit *olimit = p1->p_limit;
127 struct plimit *nlimit = NULL;
128 struct plimit *rlimit;
131 * If we are exclusive (but not threaded-exclusive), but have only
132 * one reference, we can convert the structure to copy-on-write
135 * If we were threaded but are no longer threaded we can do the same
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;
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.
152 if (olimit->p_exclusive == 0) {
153 if (olimit->p_refcnt == 1) {
156 spin_lock(&olimit->p_spin);
158 spin_unlock(&olimit->p_spin);
164 * Full-blown code-up.
167 spin_lock(&olimit->p_spin);
170 if (olimit->p_exclusive == 0) {
176 plimit_copy(olimit, nlimit);
181 spin_unlock(&olimit->p_spin);
182 nlimit = kmalloc(sizeof(*nlimit), M_SUBPROC, M_WAITOK);
183 spin_lock(&olimit->p_spin);
185 spin_unlock(&olimit->p_spin);
187 kfree(nlimit, M_SUBPROC);
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.
195 * LWPs share the same process structure so this does not bump refcnt.
198 plimit_lwp_fork(struct proc *p)
200 struct plimit *olimit;
204 if (olimit->p_exclusive == 2) {
205 KKASSERT(olimit->p_refcnt == 1);
208 if (olimit->p_refcnt == 1) {
209 olimit->p_exclusive = 2;
212 plimit_modify(p, -1, NULL);
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
221 * This routine must make the limit structure exclusive. A later fork
222 * will convert it back to copy-on-write if possible.
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).
230 plimit_modify(struct proc *p, int index, struct rlimit *rlim)
232 struct plimit *olimit;
233 struct plimit *nlimit;
234 struct plimit *rlimit;
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.
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) {
247 p->p_limit->pl_rlimit[index] = *rlim;
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.
258 spin_lock(&olimit->p_spin);
261 if (olimit->p_refcnt == 1) {
262 if (olimit->p_exclusive == 0)
263 olimit->p_exclusive = 1;
267 KKASSERT(olimit->p_exclusive == 0);
269 plimit_copy(olimit, nlimit);
270 nlimit->p_exclusive = 1;
276 spin_unlock(&olimit->p_spin);
277 nlimit = kmalloc(sizeof(*nlimit), M_SUBPROC, M_WAITOK);
278 spin_lock(&olimit->p_spin);
281 rlimit->pl_rlimit[index] = *rlim;
282 spin_unlock(&olimit->p_spin);
284 kfree(nlimit, M_SUBPROC);
288 * Destroy a process's plimit structure.
293 plimit_free(struct proc *p)
295 struct plimit *limit;
297 if ((limit = p->p_limit) != NULL) {
300 if (limit->p_refcnt == 1) {
301 limit->p_refcnt = -999;
302 kfree(limit, M_SUBPROC);
304 spin_lock(&limit->p_spin);
305 if (--limit->p_refcnt == 0) {
306 spin_unlock(&limit->p_spin);
307 kfree(limit, M_SUBPROC);
309 spin_unlock(&limit->p_spin);
316 * Modify a resource limit (from system call)
321 kern_setrlimit(u_int which, struct rlimit *limp)
323 struct proc *p = curproc;
324 struct plimit *limit;
325 struct rlimit *alimp;
328 if (which >= RLIM_NLIMITS)
332 * We will be modifying a resource, make a copy if necessary.
334 plimit_modify(p, -1, NULL);
336 alimp = &limit->pl_rlimit[which];
339 * Preserve historical bugs by treating negative limits as unsigned.
341 if (limp->rlim_cur < 0)
342 limp->rlim_cur = RLIM_INFINITY;
343 if (limp->rlim_max < 0)
344 limp->rlim_max = RLIM_INFINITY;
346 spin_lock(&limit->p_spin);
347 if (limp->rlim_cur > alimp->rlim_max ||
348 limp->rlim_max > alimp->rlim_max) {
349 spin_unlock(&limit->p_spin);
350 error = priv_check_cred(p->p_ucred, PRIV_PROC_SETRLIMIT, 0);
354 spin_unlock(&limit->p_spin);
356 if (limp->rlim_cur > limp->rlim_max)
357 limp->rlim_cur = limp->rlim_max;
361 spin_lock(&limit->p_spin);
362 if (limp->rlim_cur > RLIM_INFINITY / (rlim_t)1000000)
363 limit->p_cpulimit = RLIM_INFINITY;
365 limit->p_cpulimit = (rlim_t)1000000 * limp->rlim_cur;
366 spin_unlock(&limit->p_spin);
369 if (limp->rlim_cur > maxdsiz)
370 limp->rlim_cur = maxdsiz;
371 if (limp->rlim_max > maxdsiz)
372 limp->rlim_max = maxdsiz;
376 if (limp->rlim_cur > maxssiz)
377 limp->rlim_cur = maxssiz;
378 if (limp->rlim_max > maxssiz)
379 limp->rlim_max = maxssiz;
381 * Stack is allocated to the max at exec time with only
382 * "rlim_cur" bytes accessible. If stack limit is going
383 * up make more accessible, if going down make inaccessible.
385 spin_lock(&limit->p_spin);
386 if (limp->rlim_cur != alimp->rlim_cur) {
391 if (limp->rlim_cur > alimp->rlim_cur) {
393 size = limp->rlim_cur - alimp->rlim_cur;
394 addr = USRSTACK - limp->rlim_cur;
397 size = alimp->rlim_cur - limp->rlim_cur;
398 addr = USRSTACK - alimp->rlim_cur;
400 spin_unlock(&limit->p_spin);
401 addr = trunc_page(addr);
402 size = round_page(size);
403 vm_map_protect(&p->p_vmspace->vm_map,
404 addr, addr+size, prot, FALSE);
406 spin_unlock(&limit->p_spin);
411 if (limp->rlim_cur > maxfilesperproc)
412 limp->rlim_cur = maxfilesperproc;
413 if (limp->rlim_max > maxfilesperproc)
414 limp->rlim_max = maxfilesperproc;
418 if (limp->rlim_cur > maxprocperuid)
419 limp->rlim_cur = maxprocperuid;
420 if (limp->rlim_max > maxprocperuid)
421 limp->rlim_max = maxprocperuid;
422 if (limp->rlim_cur < 1)
424 if (limp->rlim_max < 1)
427 case RLIMIT_POSIXLOCKS:
428 if (limp->rlim_cur > maxposixlocksperuid)
429 limp->rlim_cur = maxposixlocksperuid;
430 if (limp->rlim_max > maxposixlocksperuid)
431 limp->rlim_max = maxposixlocksperuid;
434 spin_lock(&limit->p_spin);
436 spin_unlock(&limit->p_spin);
441 * The rlimit indexed by which is returned in the second argument.
446 kern_getrlimit(u_int which, struct rlimit *limp)
448 struct proc *p = curproc;
449 struct plimit *limit;
451 if (which >= RLIM_NLIMITS)
455 spin_lock(&limit->p_spin);
456 *limp = p->p_rlimit[which];
457 spin_unlock(&limit->p_spin);
462 * Determine if the cpu limit has been reached and return an operations
463 * code for the caller to perform.
468 plimit_testcpulimit(struct plimit *limit, u_int64_t ttime)
474 * Initial tests without the spinlock. This is the fast path.
475 * Any 32/64 bit glitches will fall through and retest with
478 if (limit->p_cpulimit == RLIM_INFINITY)
479 return(PLIMIT_TESTCPU_OK);
480 if (ttime <= limit->p_cpulimit)
481 return(PLIMIT_TESTCPU_OK);
483 spin_lock(&limit->p_spin);
484 if (ttime > limit->p_cpulimit) {
485 rlim = &limit->pl_rlimit[RLIMIT_CPU];
486 if (ttime / (rlim_t)1000000 >= rlim->rlim_max + 5)
487 mode = PLIMIT_TESTCPU_KILL;
489 mode = PLIMIT_TESTCPU_XCPU;
491 mode = PLIMIT_TESTCPU_OK;
493 spin_unlock(&limit->p_spin);
498 * Helper routine to copy olimit to nlimit and initialize nlimit for
499 * use. nlimit's reference count will be set to 1 and its exclusive bit
506 plimit_copy(struct plimit *olimit, struct plimit *nlimit)
510 spin_init(&nlimit->p_spin);
511 nlimit->p_refcnt = 1;
512 nlimit->p_exclusive = 0;