xref: /freebsd/sys/vm/vm_mmap.c (revision 675be9115aae86ad6b3d877155d4fd7822892105)
1 /*-
2  * Copyright (c) 1988 University of Utah.
3  * Copyright (c) 1991, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * the Systems Programming Group of the University of Utah Computer
8  * Science Department.
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  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$
35  *
36  *	@(#)vm_mmap.c	8.4 (Berkeley) 1/12/94
37  */
38 
39 /*
40  * Mapped file (mmap) interface to VM
41  */
42 
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45 
46 #include "opt_compat.h"
47 #include "opt_hwpmc_hooks.h"
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/capability.h>
52 #include <sys/kernel.h>
53 #include <sys/lock.h>
54 #include <sys/mutex.h>
55 #include <sys/sysproto.h>
56 #include <sys/filedesc.h>
57 #include <sys/priv.h>
58 #include <sys/proc.h>
59 #include <sys/racct.h>
60 #include <sys/resource.h>
61 #include <sys/resourcevar.h>
62 #include <sys/vnode.h>
63 #include <sys/fcntl.h>
64 #include <sys/file.h>
65 #include <sys/mman.h>
66 #include <sys/mount.h>
67 #include <sys/conf.h>
68 #include <sys/stat.h>
69 #include <sys/sysent.h>
70 #include <sys/vmmeter.h>
71 
72 #include <security/mac/mac_framework.h>
73 
74 #include <vm/vm.h>
75 #include <vm/vm_param.h>
76 #include <vm/pmap.h>
77 #include <vm/vm_map.h>
78 #include <vm/vm_object.h>
79 #include <vm/vm_page.h>
80 #include <vm/vm_pager.h>
81 #include <vm/vm_pageout.h>
82 #include <vm/vm_extern.h>
83 #include <vm/vm_page.h>
84 
85 #ifdef HWPMC_HOOKS
86 #include <sys/pmckern.h>
87 #endif
88 
89 #ifndef _SYS_SYSPROTO_H_
90 struct sbrk_args {
91 	int incr;
92 };
93 #endif
94 
95 static int vm_mmap_vnode(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
96     int *, struct vnode *, vm_ooffset_t *, vm_object_t *);
97 static int vm_mmap_cdev(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
98     int *, struct cdev *, vm_ooffset_t *, vm_object_t *);
99 static int vm_mmap_shm(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
100     int *, struct shmfd *, vm_ooffset_t, vm_object_t *);
101 
102 /*
103  * MPSAFE
104  */
105 /* ARGSUSED */
106 int
107 sys_sbrk(td, uap)
108 	struct thread *td;
109 	struct sbrk_args *uap;
110 {
111 	/* Not yet implemented */
112 	return (EOPNOTSUPP);
113 }
114 
115 #ifndef _SYS_SYSPROTO_H_
116 struct sstk_args {
117 	int incr;
118 };
119 #endif
120 
121 /*
122  * MPSAFE
123  */
124 /* ARGSUSED */
125 int
126 sys_sstk(td, uap)
127 	struct thread *td;
128 	struct sstk_args *uap;
129 {
130 	/* Not yet implemented */
131 	return (EOPNOTSUPP);
132 }
133 
134 #if defined(COMPAT_43)
135 #ifndef _SYS_SYSPROTO_H_
136 struct getpagesize_args {
137 	int dummy;
138 };
139 #endif
140 
141 /* ARGSUSED */
142 int
143 ogetpagesize(td, uap)
144 	struct thread *td;
145 	struct getpagesize_args *uap;
146 {
147 	/* MP SAFE */
148 	td->td_retval[0] = PAGE_SIZE;
149 	return (0);
150 }
151 #endif				/* COMPAT_43 */
152 
153 
154 /*
155  * Memory Map (mmap) system call.  Note that the file offset
156  * and address are allowed to be NOT page aligned, though if
157  * the MAP_FIXED flag it set, both must have the same remainder
158  * modulo the PAGE_SIZE (POSIX 1003.1b).  If the address is not
159  * page-aligned, the actual mapping starts at trunc_page(addr)
160  * and the return value is adjusted up by the page offset.
161  *
162  * Generally speaking, only character devices which are themselves
163  * memory-based, such as a video framebuffer, can be mmap'd.  Otherwise
164  * there would be no cache coherency between a descriptor and a VM mapping
165  * both to the same character device.
166  */
167 #ifndef _SYS_SYSPROTO_H_
168 struct mmap_args {
169 	void *addr;
170 	size_t len;
171 	int prot;
172 	int flags;
173 	int fd;
174 	long pad;
175 	off_t pos;
176 };
177 #endif
178 
179 /*
180  * MPSAFE
181  */
182 int
183 sys_mmap(td, uap)
184 	struct thread *td;
185 	struct mmap_args *uap;
186 {
187 #ifdef HWPMC_HOOKS
188 	struct pmckern_map_in pkm;
189 #endif
190 	struct file *fp;
191 	struct vnode *vp;
192 	vm_offset_t addr;
193 	vm_size_t size, pageoff;
194 	vm_prot_t cap_maxprot, prot, maxprot;
195 	void *handle;
196 	objtype_t handle_type;
197 	int flags, error;
198 	off_t pos;
199 	struct vmspace *vms = td->td_proc->p_vmspace;
200 	cap_rights_t rights;
201 
202 	addr = (vm_offset_t) uap->addr;
203 	size = uap->len;
204 	prot = uap->prot & VM_PROT_ALL;
205 	flags = uap->flags;
206 	pos = uap->pos;
207 
208 	fp = NULL;
209 
210 	/* Make sure mapping fits into numeric range, etc. */
211 	if ((uap->len == 0 && !SV_CURPROC_FLAG(SV_AOUT) &&
212 	     curproc->p_osrel >= P_OSREL_MAP_ANON) ||
213 	    ((flags & MAP_ANON) && (uap->fd != -1 || pos != 0)))
214 		return (EINVAL);
215 
216 	if (flags & MAP_STACK) {
217 		if ((uap->fd != -1) ||
218 		    ((prot & (PROT_READ | PROT_WRITE)) != (PROT_READ | PROT_WRITE)))
219 			return (EINVAL);
220 		flags |= MAP_ANON;
221 		pos = 0;
222 	}
223 
224 	/*
225 	 * Align the file position to a page boundary,
226 	 * and save its page offset component.
227 	 */
228 	pageoff = (pos & PAGE_MASK);
229 	pos -= pageoff;
230 
231 	/* Adjust size for rounding (on both ends). */
232 	size += pageoff;			/* low end... */
233 	size = (vm_size_t) round_page(size);	/* hi end */
234 
235 	/*
236 	 * Check for illegal addresses.  Watch out for address wrap... Note
237 	 * that VM_*_ADDRESS are not constants due to casts (argh).
238 	 */
239 	if (flags & MAP_FIXED) {
240 		/*
241 		 * The specified address must have the same remainder
242 		 * as the file offset taken modulo PAGE_SIZE, so it
243 		 * should be aligned after adjustment by pageoff.
244 		 */
245 		addr -= pageoff;
246 		if (addr & PAGE_MASK)
247 			return (EINVAL);
248 
249 		/* Address range must be all in user VM space. */
250 		if (addr < vm_map_min(&vms->vm_map) ||
251 		    addr + size > vm_map_max(&vms->vm_map))
252 			return (EINVAL);
253 		if (addr + size < addr)
254 			return (EINVAL);
255 	} else {
256 		/*
257 		 * XXX for non-fixed mappings where no hint is provided or
258 		 * the hint would fall in the potential heap space,
259 		 * place it after the end of the largest possible heap.
260 		 *
261 		 * There should really be a pmap call to determine a reasonable
262 		 * location.
263 		 */
264 		PROC_LOCK(td->td_proc);
265 		if (addr == 0 ||
266 		    (addr >= round_page((vm_offset_t)vms->vm_taddr) &&
267 		    addr < round_page((vm_offset_t)vms->vm_daddr +
268 		    lim_max(td->td_proc, RLIMIT_DATA))))
269 			addr = round_page((vm_offset_t)vms->vm_daddr +
270 			    lim_max(td->td_proc, RLIMIT_DATA));
271 		PROC_UNLOCK(td->td_proc);
272 	}
273 	if (flags & MAP_ANON) {
274 		/*
275 		 * Mapping blank space is trivial.
276 		 */
277 		handle = NULL;
278 		handle_type = OBJT_DEFAULT;
279 		maxprot = VM_PROT_ALL;
280 		cap_maxprot = VM_PROT_ALL;
281 	} else {
282 		/*
283 		 * Mapping file, get fp for validation and don't let the
284 		 * descriptor disappear on us if we block. Check capability
285 		 * rights, but also return the maximum rights to be combined
286 		 * with maxprot later.
287 		 */
288 		rights = CAP_MMAP;
289 		if (prot & PROT_READ)
290 			rights |= CAP_READ;
291 		if ((flags & MAP_SHARED) != 0) {
292 			if (prot & PROT_WRITE)
293 				rights |= CAP_WRITE;
294 		}
295 		if (prot & PROT_EXEC)
296 			rights |= CAP_MAPEXEC;
297 		if ((error = fget_mmap(td, uap->fd, rights, &cap_maxprot,
298 		    &fp)) != 0)
299 			goto done;
300 		if (fp->f_type == DTYPE_SHM) {
301 			handle = fp->f_data;
302 			handle_type = OBJT_SWAP;
303 			maxprot = VM_PROT_NONE;
304 
305 			/* FREAD should always be set. */
306 			if (fp->f_flag & FREAD)
307 				maxprot |= VM_PROT_EXECUTE | VM_PROT_READ;
308 			if (fp->f_flag & FWRITE)
309 				maxprot |= VM_PROT_WRITE;
310 			goto map;
311 		}
312 		if (fp->f_type != DTYPE_VNODE) {
313 			error = ENODEV;
314 			goto done;
315 		}
316 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
317     defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
318 		/*
319 		 * POSIX shared-memory objects are defined to have
320 		 * kernel persistence, and are not defined to support
321 		 * read(2)/write(2) -- or even open(2).  Thus, we can
322 		 * use MAP_ASYNC to trade on-disk coherence for speed.
323 		 * The shm_open(3) library routine turns on the FPOSIXSHM
324 		 * flag to request this behavior.
325 		 */
326 		if (fp->f_flag & FPOSIXSHM)
327 			flags |= MAP_NOSYNC;
328 #endif
329 		vp = fp->f_vnode;
330 		/*
331 		 * Ensure that file and memory protections are
332 		 * compatible.  Note that we only worry about
333 		 * writability if mapping is shared; in this case,
334 		 * current and max prot are dictated by the open file.
335 		 * XXX use the vnode instead?  Problem is: what
336 		 * credentials do we use for determination? What if
337 		 * proc does a setuid?
338 		 */
339 		if (vp->v_mount != NULL && vp->v_mount->mnt_flag & MNT_NOEXEC)
340 			maxprot = VM_PROT_NONE;
341 		else
342 			maxprot = VM_PROT_EXECUTE;
343 		if (fp->f_flag & FREAD) {
344 			maxprot |= VM_PROT_READ;
345 		} else if (prot & PROT_READ) {
346 			error = EACCES;
347 			goto done;
348 		}
349 		/*
350 		 * If we are sharing potential changes (either via
351 		 * MAP_SHARED or via the implicit sharing of character
352 		 * device mappings), and we are trying to get write
353 		 * permission although we opened it without asking
354 		 * for it, bail out.
355 		 */
356 		if ((flags & MAP_SHARED) != 0) {
357 			if ((fp->f_flag & FWRITE) != 0) {
358 				maxprot |= VM_PROT_WRITE;
359 			} else if ((prot & PROT_WRITE) != 0) {
360 				error = EACCES;
361 				goto done;
362 			}
363 		} else if (vp->v_type != VCHR || (fp->f_flag & FWRITE) != 0) {
364 			maxprot |= VM_PROT_WRITE;
365 			cap_maxprot |= VM_PROT_WRITE;
366 		}
367 		handle = (void *)vp;
368 		handle_type = OBJT_VNODE;
369 	}
370 map:
371 	td->td_fpop = fp;
372 	maxprot &= cap_maxprot;
373 	error = vm_mmap(&vms->vm_map, &addr, size, prot, maxprot,
374 	    flags, handle_type, handle, pos);
375 	td->td_fpop = NULL;
376 #ifdef HWPMC_HOOKS
377 	/* inform hwpmc(4) if an executable is being mapped */
378 	if (error == 0 && handle_type == OBJT_VNODE &&
379 	    (prot & PROT_EXEC)) {
380 		pkm.pm_file = handle;
381 		pkm.pm_address = (uintptr_t) addr;
382 		PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm);
383 	}
384 #endif
385 	if (error == 0)
386 		td->td_retval[0] = (register_t) (addr + pageoff);
387 done:
388 	if (fp)
389 		fdrop(fp, td);
390 
391 	return (error);
392 }
393 
394 int
395 freebsd6_mmap(struct thread *td, struct freebsd6_mmap_args *uap)
396 {
397 	struct mmap_args oargs;
398 
399 	oargs.addr = uap->addr;
400 	oargs.len = uap->len;
401 	oargs.prot = uap->prot;
402 	oargs.flags = uap->flags;
403 	oargs.fd = uap->fd;
404 	oargs.pos = uap->pos;
405 	return (sys_mmap(td, &oargs));
406 }
407 
408 #ifdef COMPAT_43
409 #ifndef _SYS_SYSPROTO_H_
410 struct ommap_args {
411 	caddr_t addr;
412 	int len;
413 	int prot;
414 	int flags;
415 	int fd;
416 	long pos;
417 };
418 #endif
419 int
420 ommap(td, uap)
421 	struct thread *td;
422 	struct ommap_args *uap;
423 {
424 	struct mmap_args nargs;
425 	static const char cvtbsdprot[8] = {
426 		0,
427 		PROT_EXEC,
428 		PROT_WRITE,
429 		PROT_EXEC | PROT_WRITE,
430 		PROT_READ,
431 		PROT_EXEC | PROT_READ,
432 		PROT_WRITE | PROT_READ,
433 		PROT_EXEC | PROT_WRITE | PROT_READ,
434 	};
435 
436 #define	OMAP_ANON	0x0002
437 #define	OMAP_COPY	0x0020
438 #define	OMAP_SHARED	0x0010
439 #define	OMAP_FIXED	0x0100
440 
441 	nargs.addr = uap->addr;
442 	nargs.len = uap->len;
443 	nargs.prot = cvtbsdprot[uap->prot & 0x7];
444 	nargs.flags = 0;
445 	if (uap->flags & OMAP_ANON)
446 		nargs.flags |= MAP_ANON;
447 	if (uap->flags & OMAP_COPY)
448 		nargs.flags |= MAP_COPY;
449 	if (uap->flags & OMAP_SHARED)
450 		nargs.flags |= MAP_SHARED;
451 	else
452 		nargs.flags |= MAP_PRIVATE;
453 	if (uap->flags & OMAP_FIXED)
454 		nargs.flags |= MAP_FIXED;
455 	nargs.fd = uap->fd;
456 	nargs.pos = uap->pos;
457 	return (sys_mmap(td, &nargs));
458 }
459 #endif				/* COMPAT_43 */
460 
461 
462 #ifndef _SYS_SYSPROTO_H_
463 struct msync_args {
464 	void *addr;
465 	size_t len;
466 	int flags;
467 };
468 #endif
469 /*
470  * MPSAFE
471  */
472 int
473 sys_msync(td, uap)
474 	struct thread *td;
475 	struct msync_args *uap;
476 {
477 	vm_offset_t addr;
478 	vm_size_t size, pageoff;
479 	int flags;
480 	vm_map_t map;
481 	int rv;
482 
483 	addr = (vm_offset_t) uap->addr;
484 	size = uap->len;
485 	flags = uap->flags;
486 
487 	pageoff = (addr & PAGE_MASK);
488 	addr -= pageoff;
489 	size += pageoff;
490 	size = (vm_size_t) round_page(size);
491 	if (addr + size < addr)
492 		return (EINVAL);
493 
494 	if ((flags & (MS_ASYNC|MS_INVALIDATE)) == (MS_ASYNC|MS_INVALIDATE))
495 		return (EINVAL);
496 
497 	map = &td->td_proc->p_vmspace->vm_map;
498 
499 	/*
500 	 * Clean the pages and interpret the return value.
501 	 */
502 	rv = vm_map_sync(map, addr, addr + size, (flags & MS_ASYNC) == 0,
503 	    (flags & MS_INVALIDATE) != 0);
504 	switch (rv) {
505 	case KERN_SUCCESS:
506 		return (0);
507 	case KERN_INVALID_ADDRESS:
508 		return (EINVAL);	/* Sun returns ENOMEM? */
509 	case KERN_INVALID_ARGUMENT:
510 		return (EBUSY);
511 	default:
512 		return (EINVAL);
513 	}
514 }
515 
516 #ifndef _SYS_SYSPROTO_H_
517 struct munmap_args {
518 	void *addr;
519 	size_t len;
520 };
521 #endif
522 /*
523  * MPSAFE
524  */
525 int
526 sys_munmap(td, uap)
527 	struct thread *td;
528 	struct munmap_args *uap;
529 {
530 #ifdef HWPMC_HOOKS
531 	struct pmckern_map_out pkm;
532 	vm_map_entry_t entry;
533 #endif
534 	vm_offset_t addr;
535 	vm_size_t size, pageoff;
536 	vm_map_t map;
537 
538 	addr = (vm_offset_t) uap->addr;
539 	size = uap->len;
540 	if (size == 0)
541 		return (EINVAL);
542 
543 	pageoff = (addr & PAGE_MASK);
544 	addr -= pageoff;
545 	size += pageoff;
546 	size = (vm_size_t) round_page(size);
547 	if (addr + size < addr)
548 		return (EINVAL);
549 
550 	/*
551 	 * Check for illegal addresses.  Watch out for address wrap...
552 	 */
553 	map = &td->td_proc->p_vmspace->vm_map;
554 	if (addr < vm_map_min(map) || addr + size > vm_map_max(map))
555 		return (EINVAL);
556 	vm_map_lock(map);
557 #ifdef HWPMC_HOOKS
558 	/*
559 	 * Inform hwpmc if the address range being unmapped contains
560 	 * an executable region.
561 	 */
562 	pkm.pm_address = (uintptr_t) NULL;
563 	if (vm_map_lookup_entry(map, addr, &entry)) {
564 		for (;
565 		     entry != &map->header && entry->start < addr + size;
566 		     entry = entry->next) {
567 			if (vm_map_check_protection(map, entry->start,
568 				entry->end, VM_PROT_EXECUTE) == TRUE) {
569 				pkm.pm_address = (uintptr_t) addr;
570 				pkm.pm_size = (size_t) size;
571 				break;
572 			}
573 		}
574 	}
575 #endif
576 	vm_map_delete(map, addr, addr + size);
577 
578 #ifdef HWPMC_HOOKS
579 	/* downgrade the lock to prevent a LOR with the pmc-sx lock */
580 	vm_map_lock_downgrade(map);
581 	if (pkm.pm_address != (uintptr_t) NULL)
582 		PMC_CALL_HOOK(td, PMC_FN_MUNMAP, (void *) &pkm);
583 	vm_map_unlock_read(map);
584 #else
585 	vm_map_unlock(map);
586 #endif
587 	/* vm_map_delete returns nothing but KERN_SUCCESS anyway */
588 	return (0);
589 }
590 
591 #ifndef _SYS_SYSPROTO_H_
592 struct mprotect_args {
593 	const void *addr;
594 	size_t len;
595 	int prot;
596 };
597 #endif
598 /*
599  * MPSAFE
600  */
601 int
602 sys_mprotect(td, uap)
603 	struct thread *td;
604 	struct mprotect_args *uap;
605 {
606 	vm_offset_t addr;
607 	vm_size_t size, pageoff;
608 	vm_prot_t prot;
609 
610 	addr = (vm_offset_t) uap->addr;
611 	size = uap->len;
612 	prot = uap->prot & VM_PROT_ALL;
613 
614 	pageoff = (addr & PAGE_MASK);
615 	addr -= pageoff;
616 	size += pageoff;
617 	size = (vm_size_t) round_page(size);
618 	if (addr + size < addr)
619 		return (EINVAL);
620 
621 	switch (vm_map_protect(&td->td_proc->p_vmspace->vm_map, addr,
622 	    addr + size, prot, FALSE)) {
623 	case KERN_SUCCESS:
624 		return (0);
625 	case KERN_PROTECTION_FAILURE:
626 		return (EACCES);
627 	case KERN_RESOURCE_SHORTAGE:
628 		return (ENOMEM);
629 	}
630 	return (EINVAL);
631 }
632 
633 #ifndef _SYS_SYSPROTO_H_
634 struct minherit_args {
635 	void *addr;
636 	size_t len;
637 	int inherit;
638 };
639 #endif
640 /*
641  * MPSAFE
642  */
643 int
644 sys_minherit(td, uap)
645 	struct thread *td;
646 	struct minherit_args *uap;
647 {
648 	vm_offset_t addr;
649 	vm_size_t size, pageoff;
650 	vm_inherit_t inherit;
651 
652 	addr = (vm_offset_t)uap->addr;
653 	size = uap->len;
654 	inherit = uap->inherit;
655 
656 	pageoff = (addr & PAGE_MASK);
657 	addr -= pageoff;
658 	size += pageoff;
659 	size = (vm_size_t) round_page(size);
660 	if (addr + size < addr)
661 		return (EINVAL);
662 
663 	switch (vm_map_inherit(&td->td_proc->p_vmspace->vm_map, addr,
664 	    addr + size, inherit)) {
665 	case KERN_SUCCESS:
666 		return (0);
667 	case KERN_PROTECTION_FAILURE:
668 		return (EACCES);
669 	}
670 	return (EINVAL);
671 }
672 
673 #ifndef _SYS_SYSPROTO_H_
674 struct madvise_args {
675 	void *addr;
676 	size_t len;
677 	int behav;
678 };
679 #endif
680 
681 /*
682  * MPSAFE
683  */
684 /* ARGSUSED */
685 int
686 sys_madvise(td, uap)
687 	struct thread *td;
688 	struct madvise_args *uap;
689 {
690 	vm_offset_t start, end;
691 	vm_map_t map;
692 	struct proc *p;
693 	int error;
694 
695 	/*
696 	 * Check for our special case, advising the swap pager we are
697 	 * "immortal."
698 	 */
699 	if (uap->behav == MADV_PROTECT) {
700 		error = priv_check(td, PRIV_VM_MADV_PROTECT);
701 		if (error == 0) {
702 			p = td->td_proc;
703 			PROC_LOCK(p);
704 			p->p_flag |= P_PROTECTED;
705 			PROC_UNLOCK(p);
706 		}
707 		return (error);
708 	}
709 	/*
710 	 * Check for illegal behavior
711 	 */
712 	if (uap->behav < 0 || uap->behav > MADV_CORE)
713 		return (EINVAL);
714 	/*
715 	 * Check for illegal addresses.  Watch out for address wrap... Note
716 	 * that VM_*_ADDRESS are not constants due to casts (argh).
717 	 */
718 	map = &td->td_proc->p_vmspace->vm_map;
719 	if ((vm_offset_t)uap->addr < vm_map_min(map) ||
720 	    (vm_offset_t)uap->addr + uap->len > vm_map_max(map))
721 		return (EINVAL);
722 	if (((vm_offset_t) uap->addr + uap->len) < (vm_offset_t) uap->addr)
723 		return (EINVAL);
724 
725 	/*
726 	 * Since this routine is only advisory, we default to conservative
727 	 * behavior.
728 	 */
729 	start = trunc_page((vm_offset_t) uap->addr);
730 	end = round_page((vm_offset_t) uap->addr + uap->len);
731 
732 	if (vm_map_madvise(map, start, end, uap->behav))
733 		return (EINVAL);
734 	return (0);
735 }
736 
737 #ifndef _SYS_SYSPROTO_H_
738 struct mincore_args {
739 	const void *addr;
740 	size_t len;
741 	char *vec;
742 };
743 #endif
744 
745 /*
746  * MPSAFE
747  */
748 /* ARGSUSED */
749 int
750 sys_mincore(td, uap)
751 	struct thread *td;
752 	struct mincore_args *uap;
753 {
754 	vm_offset_t addr, first_addr;
755 	vm_offset_t end, cend;
756 	pmap_t pmap;
757 	vm_map_t map;
758 	char *vec;
759 	int error = 0;
760 	int vecindex, lastvecindex;
761 	vm_map_entry_t current;
762 	vm_map_entry_t entry;
763 	vm_object_t object;
764 	vm_paddr_t locked_pa;
765 	vm_page_t m;
766 	vm_pindex_t pindex;
767 	int mincoreinfo;
768 	unsigned int timestamp;
769 	boolean_t locked;
770 
771 	/*
772 	 * Make sure that the addresses presented are valid for user
773 	 * mode.
774 	 */
775 	first_addr = addr = trunc_page((vm_offset_t) uap->addr);
776 	end = addr + (vm_size_t)round_page(uap->len);
777 	map = &td->td_proc->p_vmspace->vm_map;
778 	if (end > vm_map_max(map) || end < addr)
779 		return (ENOMEM);
780 
781 	/*
782 	 * Address of byte vector
783 	 */
784 	vec = uap->vec;
785 
786 	pmap = vmspace_pmap(td->td_proc->p_vmspace);
787 
788 	vm_map_lock_read(map);
789 RestartScan:
790 	timestamp = map->timestamp;
791 
792 	if (!vm_map_lookup_entry(map, addr, &entry)) {
793 		vm_map_unlock_read(map);
794 		return (ENOMEM);
795 	}
796 
797 	/*
798 	 * Do this on a map entry basis so that if the pages are not
799 	 * in the current processes address space, we can easily look
800 	 * up the pages elsewhere.
801 	 */
802 	lastvecindex = -1;
803 	for (current = entry;
804 	    (current != &map->header) && (current->start < end);
805 	    current = current->next) {
806 
807 		/*
808 		 * check for contiguity
809 		 */
810 		if (current->end < end &&
811 		    (entry->next == &map->header ||
812 		     current->next->start > current->end)) {
813 			vm_map_unlock_read(map);
814 			return (ENOMEM);
815 		}
816 
817 		/*
818 		 * ignore submaps (for now) or null objects
819 		 */
820 		if ((current->eflags & MAP_ENTRY_IS_SUB_MAP) ||
821 			current->object.vm_object == NULL)
822 			continue;
823 
824 		/*
825 		 * limit this scan to the current map entry and the
826 		 * limits for the mincore call
827 		 */
828 		if (addr < current->start)
829 			addr = current->start;
830 		cend = current->end;
831 		if (cend > end)
832 			cend = end;
833 
834 		/*
835 		 * scan this entry one page at a time
836 		 */
837 		while (addr < cend) {
838 			/*
839 			 * Check pmap first, it is likely faster, also
840 			 * it can provide info as to whether we are the
841 			 * one referencing or modifying the page.
842 			 */
843 			object = NULL;
844 			locked_pa = 0;
845 		retry:
846 			m = NULL;
847 			mincoreinfo = pmap_mincore(pmap, addr, &locked_pa);
848 			if (locked_pa != 0) {
849 				/*
850 				 * The page is mapped by this process but not
851 				 * both accessed and modified.  It is also
852 				 * managed.  Acquire the object lock so that
853 				 * other mappings might be examined.
854 				 */
855 				m = PHYS_TO_VM_PAGE(locked_pa);
856 				if (m->object != object) {
857 					if (object != NULL)
858 						VM_OBJECT_UNLOCK(object);
859 					object = m->object;
860 					locked = VM_OBJECT_TRYLOCK(object);
861 					vm_page_unlock(m);
862 					if (!locked) {
863 						VM_OBJECT_LOCK(object);
864 						vm_page_lock(m);
865 						goto retry;
866 					}
867 				} else
868 					vm_page_unlock(m);
869 				KASSERT(m->valid == VM_PAGE_BITS_ALL,
870 				    ("mincore: page %p is mapped but invalid",
871 				    m));
872 			} else if (mincoreinfo == 0) {
873 				/*
874 				 * The page is not mapped by this process.  If
875 				 * the object implements managed pages, then
876 				 * determine if the page is resident so that
877 				 * the mappings might be examined.
878 				 */
879 				if (current->object.vm_object != object) {
880 					if (object != NULL)
881 						VM_OBJECT_UNLOCK(object);
882 					object = current->object.vm_object;
883 					VM_OBJECT_LOCK(object);
884 				}
885 				if (object->type == OBJT_DEFAULT ||
886 				    object->type == OBJT_SWAP ||
887 				    object->type == OBJT_VNODE) {
888 					pindex = OFF_TO_IDX(current->offset +
889 					    (addr - current->start));
890 					m = vm_page_lookup(object, pindex);
891 					if (m != NULL && m->valid == 0)
892 						m = NULL;
893 					if (m != NULL)
894 						mincoreinfo = MINCORE_INCORE;
895 				}
896 			}
897 			if (m != NULL) {
898 				/* Examine other mappings to the page. */
899 				if (m->dirty == 0 && pmap_is_modified(m))
900 					vm_page_dirty(m);
901 				if (m->dirty != 0)
902 					mincoreinfo |= MINCORE_MODIFIED_OTHER;
903 				/*
904 				 * The first test for PGA_REFERENCED is an
905 				 * optimization.  The second test is
906 				 * required because a concurrent pmap
907 				 * operation could clear the last reference
908 				 * and set PGA_REFERENCED before the call to
909 				 * pmap_is_referenced().
910 				 */
911 				if ((m->aflags & PGA_REFERENCED) != 0 ||
912 				    pmap_is_referenced(m) ||
913 				    (m->aflags & PGA_REFERENCED) != 0)
914 					mincoreinfo |= MINCORE_REFERENCED_OTHER;
915 			}
916 			if (object != NULL)
917 				VM_OBJECT_UNLOCK(object);
918 
919 			/*
920 			 * subyte may page fault.  In case it needs to modify
921 			 * the map, we release the lock.
922 			 */
923 			vm_map_unlock_read(map);
924 
925 			/*
926 			 * calculate index into user supplied byte vector
927 			 */
928 			vecindex = OFF_TO_IDX(addr - first_addr);
929 
930 			/*
931 			 * If we have skipped map entries, we need to make sure that
932 			 * the byte vector is zeroed for those skipped entries.
933 			 */
934 			while ((lastvecindex + 1) < vecindex) {
935 				error = subyte(vec + lastvecindex, 0);
936 				if (error) {
937 					error = EFAULT;
938 					goto done2;
939 				}
940 				++lastvecindex;
941 			}
942 
943 			/*
944 			 * Pass the page information to the user
945 			 */
946 			error = subyte(vec + vecindex, mincoreinfo);
947 			if (error) {
948 				error = EFAULT;
949 				goto done2;
950 			}
951 
952 			/*
953 			 * If the map has changed, due to the subyte, the previous
954 			 * output may be invalid.
955 			 */
956 			vm_map_lock_read(map);
957 			if (timestamp != map->timestamp)
958 				goto RestartScan;
959 
960 			lastvecindex = vecindex;
961 			addr += PAGE_SIZE;
962 		}
963 	}
964 
965 	/*
966 	 * subyte may page fault.  In case it needs to modify
967 	 * the map, we release the lock.
968 	 */
969 	vm_map_unlock_read(map);
970 
971 	/*
972 	 * Zero the last entries in the byte vector.
973 	 */
974 	vecindex = OFF_TO_IDX(end - first_addr);
975 	while ((lastvecindex + 1) < vecindex) {
976 		error = subyte(vec + lastvecindex, 0);
977 		if (error) {
978 			error = EFAULT;
979 			goto done2;
980 		}
981 		++lastvecindex;
982 	}
983 
984 	/*
985 	 * If the map has changed, due to the subyte, the previous
986 	 * output may be invalid.
987 	 */
988 	vm_map_lock_read(map);
989 	if (timestamp != map->timestamp)
990 		goto RestartScan;
991 	vm_map_unlock_read(map);
992 done2:
993 	return (error);
994 }
995 
996 #ifndef _SYS_SYSPROTO_H_
997 struct mlock_args {
998 	const void *addr;
999 	size_t len;
1000 };
1001 #endif
1002 /*
1003  * MPSAFE
1004  */
1005 int
1006 sys_mlock(td, uap)
1007 	struct thread *td;
1008 	struct mlock_args *uap;
1009 {
1010 	struct proc *proc;
1011 	vm_offset_t addr, end, last, start;
1012 	vm_size_t npages, size;
1013 	unsigned long nsize;
1014 	int error;
1015 
1016 	error = priv_check(td, PRIV_VM_MLOCK);
1017 	if (error)
1018 		return (error);
1019 	addr = (vm_offset_t)uap->addr;
1020 	size = uap->len;
1021 	last = addr + size;
1022 	start = trunc_page(addr);
1023 	end = round_page(last);
1024 	if (last < addr || end < addr)
1025 		return (EINVAL);
1026 	npages = atop(end - start);
1027 	if (npages > vm_page_max_wired)
1028 		return (ENOMEM);
1029 	proc = td->td_proc;
1030 	PROC_LOCK(proc);
1031 	nsize = ptoa(npages +
1032 	    pmap_wired_count(vm_map_pmap(&proc->p_vmspace->vm_map)));
1033 	if (nsize > lim_cur(proc, RLIMIT_MEMLOCK)) {
1034 		PROC_UNLOCK(proc);
1035 		return (ENOMEM);
1036 	}
1037 	PROC_UNLOCK(proc);
1038 	if (npages + cnt.v_wire_count > vm_page_max_wired)
1039 		return (EAGAIN);
1040 #ifdef RACCT
1041 	PROC_LOCK(proc);
1042 	error = racct_set(proc, RACCT_MEMLOCK, nsize);
1043 	PROC_UNLOCK(proc);
1044 	if (error != 0)
1045 		return (ENOMEM);
1046 #endif
1047 	error = vm_map_wire(&proc->p_vmspace->vm_map, start, end,
1048 	    VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
1049 #ifdef RACCT
1050 	if (error != KERN_SUCCESS) {
1051 		PROC_LOCK(proc);
1052 		racct_set(proc, RACCT_MEMLOCK,
1053 		    ptoa(pmap_wired_count(vm_map_pmap(&proc->p_vmspace->vm_map))));
1054 		PROC_UNLOCK(proc);
1055 	}
1056 #endif
1057 	return (error == KERN_SUCCESS ? 0 : ENOMEM);
1058 }
1059 
1060 #ifndef _SYS_SYSPROTO_H_
1061 struct mlockall_args {
1062 	int	how;
1063 };
1064 #endif
1065 
1066 /*
1067  * MPSAFE
1068  */
1069 int
1070 sys_mlockall(td, uap)
1071 	struct thread *td;
1072 	struct mlockall_args *uap;
1073 {
1074 	vm_map_t map;
1075 	int error;
1076 
1077 	map = &td->td_proc->p_vmspace->vm_map;
1078 	error = 0;
1079 
1080 	if ((uap->how == 0) || ((uap->how & ~(MCL_CURRENT|MCL_FUTURE)) != 0))
1081 		return (EINVAL);
1082 
1083 #if 0
1084 	/*
1085 	 * If wiring all pages in the process would cause it to exceed
1086 	 * a hard resource limit, return ENOMEM.
1087 	 */
1088 	PROC_LOCK(td->td_proc);
1089 	if (map->size > lim_cur(td->td_proc, RLIMIT_MEMLOCK)) {
1090 		PROC_UNLOCK(td->td_proc);
1091 		return (ENOMEM);
1092 	}
1093 	PROC_UNLOCK(td->td_proc);
1094 #else
1095 	error = priv_check(td, PRIV_VM_MLOCK);
1096 	if (error)
1097 		return (error);
1098 #endif
1099 #ifdef RACCT
1100 	PROC_LOCK(td->td_proc);
1101 	error = racct_set(td->td_proc, RACCT_MEMLOCK, map->size);
1102 	PROC_UNLOCK(td->td_proc);
1103 	if (error != 0)
1104 		return (ENOMEM);
1105 #endif
1106 
1107 	if (uap->how & MCL_FUTURE) {
1108 		vm_map_lock(map);
1109 		vm_map_modflags(map, MAP_WIREFUTURE, 0);
1110 		vm_map_unlock(map);
1111 		error = 0;
1112 	}
1113 
1114 	if (uap->how & MCL_CURRENT) {
1115 		/*
1116 		 * P1003.1-2001 mandates that all currently mapped pages
1117 		 * will be memory resident and locked (wired) upon return
1118 		 * from mlockall(). vm_map_wire() will wire pages, by
1119 		 * calling vm_fault_wire() for each page in the region.
1120 		 */
1121 		error = vm_map_wire(map, vm_map_min(map), vm_map_max(map),
1122 		    VM_MAP_WIRE_USER|VM_MAP_WIRE_HOLESOK);
1123 		error = (error == KERN_SUCCESS ? 0 : EAGAIN);
1124 	}
1125 #ifdef RACCT
1126 	if (error != KERN_SUCCESS) {
1127 		PROC_LOCK(td->td_proc);
1128 		racct_set(td->td_proc, RACCT_MEMLOCK,
1129 		    ptoa(pmap_wired_count(vm_map_pmap(&td->td_proc->p_vmspace->vm_map))));
1130 		PROC_UNLOCK(td->td_proc);
1131 	}
1132 #endif
1133 
1134 	return (error);
1135 }
1136 
1137 #ifndef _SYS_SYSPROTO_H_
1138 struct munlockall_args {
1139 	register_t dummy;
1140 };
1141 #endif
1142 
1143 /*
1144  * MPSAFE
1145  */
1146 int
1147 sys_munlockall(td, uap)
1148 	struct thread *td;
1149 	struct munlockall_args *uap;
1150 {
1151 	vm_map_t map;
1152 	int error;
1153 
1154 	map = &td->td_proc->p_vmspace->vm_map;
1155 	error = priv_check(td, PRIV_VM_MUNLOCK);
1156 	if (error)
1157 		return (error);
1158 
1159 	/* Clear the MAP_WIREFUTURE flag from this vm_map. */
1160 	vm_map_lock(map);
1161 	vm_map_modflags(map, 0, MAP_WIREFUTURE);
1162 	vm_map_unlock(map);
1163 
1164 	/* Forcibly unwire all pages. */
1165 	error = vm_map_unwire(map, vm_map_min(map), vm_map_max(map),
1166 	    VM_MAP_WIRE_USER|VM_MAP_WIRE_HOLESOK);
1167 #ifdef RACCT
1168 	if (error == KERN_SUCCESS) {
1169 		PROC_LOCK(td->td_proc);
1170 		racct_set(td->td_proc, RACCT_MEMLOCK, 0);
1171 		PROC_UNLOCK(td->td_proc);
1172 	}
1173 #endif
1174 
1175 	return (error);
1176 }
1177 
1178 #ifndef _SYS_SYSPROTO_H_
1179 struct munlock_args {
1180 	const void *addr;
1181 	size_t len;
1182 };
1183 #endif
1184 /*
1185  * MPSAFE
1186  */
1187 int
1188 sys_munlock(td, uap)
1189 	struct thread *td;
1190 	struct munlock_args *uap;
1191 {
1192 	vm_offset_t addr, end, last, start;
1193 	vm_size_t size;
1194 	int error;
1195 
1196 	error = priv_check(td, PRIV_VM_MUNLOCK);
1197 	if (error)
1198 		return (error);
1199 	addr = (vm_offset_t)uap->addr;
1200 	size = uap->len;
1201 	last = addr + size;
1202 	start = trunc_page(addr);
1203 	end = round_page(last);
1204 	if (last < addr || end < addr)
1205 		return (EINVAL);
1206 	error = vm_map_unwire(&td->td_proc->p_vmspace->vm_map, start, end,
1207 	    VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
1208 #ifdef RACCT
1209 	if (error == KERN_SUCCESS) {
1210 		PROC_LOCK(td->td_proc);
1211 		racct_sub(td->td_proc, RACCT_MEMLOCK, ptoa(end - start));
1212 		PROC_UNLOCK(td->td_proc);
1213 	}
1214 #endif
1215 	return (error == KERN_SUCCESS ? 0 : ENOMEM);
1216 }
1217 
1218 /*
1219  * vm_mmap_vnode()
1220  *
1221  * MPSAFE
1222  *
1223  * Helper function for vm_mmap.  Perform sanity check specific for mmap
1224  * operations on vnodes.
1225  */
1226 int
1227 vm_mmap_vnode(struct thread *td, vm_size_t objsize,
1228     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
1229     struct vnode *vp, vm_ooffset_t *foffp, vm_object_t *objp)
1230 {
1231 	struct vattr va;
1232 	vm_object_t obj;
1233 	vm_offset_t foff;
1234 	struct mount *mp;
1235 	struct ucred *cred;
1236 	int error, flags;
1237 	int vfslocked;
1238 
1239 	mp = vp->v_mount;
1240 	cred = td->td_ucred;
1241 	vfslocked = VFS_LOCK_GIANT(mp);
1242 	if ((error = vget(vp, LK_SHARED, td)) != 0) {
1243 		VFS_UNLOCK_GIANT(vfslocked);
1244 		return (error);
1245 	}
1246 	foff = *foffp;
1247 	flags = *flagsp;
1248 	obj = vp->v_object;
1249 	if (vp->v_type == VREG) {
1250 		/*
1251 		 * Get the proper underlying object
1252 		 */
1253 		if (obj == NULL) {
1254 			error = EINVAL;
1255 			goto done;
1256 		}
1257 		if (obj->handle != vp) {
1258 			vput(vp);
1259 			vp = (struct vnode*)obj->handle;
1260 			vget(vp, LK_SHARED, td);
1261 		}
1262 	} else if (vp->v_type == VCHR) {
1263 		error = vm_mmap_cdev(td, objsize, prot, maxprotp, flagsp,
1264 		    vp->v_rdev, foffp, objp);
1265 		if (error == 0)
1266 			goto mark_atime;
1267 		goto done;
1268 	} else {
1269 		error = EINVAL;
1270 		goto done;
1271 	}
1272 	if ((error = VOP_GETATTR(vp, &va, cred)))
1273 		goto done;
1274 #ifdef MAC
1275 	error = mac_vnode_check_mmap(cred, vp, prot, flags);
1276 	if (error != 0)
1277 		goto done;
1278 #endif
1279 	if ((flags & MAP_SHARED) != 0) {
1280 		if ((va.va_flags & (SF_SNAPSHOT|IMMUTABLE|APPEND)) != 0) {
1281 			if (prot & PROT_WRITE) {
1282 				error = EPERM;
1283 				goto done;
1284 			}
1285 			*maxprotp &= ~VM_PROT_WRITE;
1286 		}
1287 	}
1288 	/*
1289 	 * If it is a regular file without any references
1290 	 * we do not need to sync it.
1291 	 * Adjust object size to be the size of actual file.
1292 	 */
1293 	objsize = round_page(va.va_size);
1294 	if (va.va_nlink == 0)
1295 		flags |= MAP_NOSYNC;
1296 	obj = vm_pager_allocate(OBJT_VNODE, vp, objsize, prot, foff, td->td_ucred);
1297 	if (obj == NULL) {
1298 		error = ENOMEM;
1299 		goto done;
1300 	}
1301 	*objp = obj;
1302 	*flagsp = flags;
1303 
1304 mark_atime:
1305 	vfs_mark_atime(vp, cred);
1306 
1307 done:
1308 	vput(vp);
1309 	VFS_UNLOCK_GIANT(vfslocked);
1310 	return (error);
1311 }
1312 
1313 /*
1314  * vm_mmap_cdev()
1315  *
1316  * MPSAFE
1317  *
1318  * Helper function for vm_mmap.  Perform sanity check specific for mmap
1319  * operations on cdevs.
1320  */
1321 int
1322 vm_mmap_cdev(struct thread *td, vm_size_t objsize,
1323     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
1324     struct cdev *cdev, vm_ooffset_t *foff, vm_object_t *objp)
1325 {
1326 	vm_object_t obj;
1327 	struct cdevsw *dsw;
1328 	int error, flags, ref;
1329 
1330 	flags = *flagsp;
1331 
1332 	dsw = dev_refthread(cdev, &ref);
1333 	if (dsw == NULL)
1334 		return (ENXIO);
1335 	if (dsw->d_flags & D_MMAP_ANON) {
1336 		dev_relthread(cdev, ref);
1337 		*maxprotp = VM_PROT_ALL;
1338 		*flagsp |= MAP_ANON;
1339 		return (0);
1340 	}
1341 	/*
1342 	 * cdevs do not provide private mappings of any kind.
1343 	 */
1344 	if ((*maxprotp & VM_PROT_WRITE) == 0 &&
1345 	    (prot & PROT_WRITE) != 0) {
1346 		dev_relthread(cdev, ref);
1347 		return (EACCES);
1348 	}
1349 	if (flags & (MAP_PRIVATE|MAP_COPY)) {
1350 		dev_relthread(cdev, ref);
1351 		return (EINVAL);
1352 	}
1353 	/*
1354 	 * Force device mappings to be shared.
1355 	 */
1356 	flags |= MAP_SHARED;
1357 #ifdef MAC_XXX
1358 	error = mac_cdev_check_mmap(td->td_ucred, cdev, prot);
1359 	if (error != 0) {
1360 		dev_relthread(cdev, ref);
1361 		return (error);
1362 	}
1363 #endif
1364 	/*
1365 	 * First, try d_mmap_single().  If that is not implemented
1366 	 * (returns ENODEV), fall back to using the device pager.
1367 	 * Note that d_mmap_single() must return a reference to the
1368 	 * object (it needs to bump the reference count of the object
1369 	 * it returns somehow).
1370 	 *
1371 	 * XXX assumes VM_PROT_* == PROT_*
1372 	 */
1373 	error = dsw->d_mmap_single(cdev, foff, objsize, objp, (int)prot);
1374 	dev_relthread(cdev, ref);
1375 	if (error != ENODEV)
1376 		return (error);
1377 	obj = vm_pager_allocate(OBJT_DEVICE, cdev, objsize, prot, *foff,
1378 	    td->td_ucred);
1379 	if (obj == NULL)
1380 		return (EINVAL);
1381 	*objp = obj;
1382 	*flagsp = flags;
1383 	return (0);
1384 }
1385 
1386 /*
1387  * vm_mmap_shm()
1388  *
1389  * MPSAFE
1390  *
1391  * Helper function for vm_mmap.  Perform sanity check specific for mmap
1392  * operations on shm file descriptors.
1393  */
1394 int
1395 vm_mmap_shm(struct thread *td, vm_size_t objsize,
1396     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
1397     struct shmfd *shmfd, vm_ooffset_t foff, vm_object_t *objp)
1398 {
1399 	int error;
1400 
1401 	if ((*flagsp & MAP_SHARED) != 0 &&
1402 	    (*maxprotp & VM_PROT_WRITE) == 0 &&
1403 	    (prot & PROT_WRITE) != 0)
1404 		return (EACCES);
1405 #ifdef MAC
1406 	error = mac_posixshm_check_mmap(td->td_ucred, shmfd, prot, *flagsp);
1407 	if (error != 0)
1408 		return (error);
1409 #endif
1410 	error = shm_mmap(shmfd, objsize, foff, objp);
1411 	if (error)
1412 		return (error);
1413 	return (0);
1414 }
1415 
1416 /*
1417  * vm_mmap()
1418  *
1419  * MPSAFE
1420  *
1421  * Internal version of mmap.  Currently used by mmap, exec, and sys5
1422  * shared memory.  Handle is either a vnode pointer or NULL for MAP_ANON.
1423  */
1424 int
1425 vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot,
1426 	vm_prot_t maxprot, int flags,
1427 	objtype_t handle_type, void *handle,
1428 	vm_ooffset_t foff)
1429 {
1430 	boolean_t fitit;
1431 	vm_object_t object = NULL;
1432 	int rv = KERN_SUCCESS;
1433 	int docow, error;
1434 	struct thread *td = curthread;
1435 
1436 	if (size == 0)
1437 		return (0);
1438 
1439 	size = round_page(size);
1440 
1441 	PROC_LOCK(td->td_proc);
1442 	if (td->td_proc->p_vmspace->vm_map.size + size >
1443 	    lim_cur(td->td_proc, RLIMIT_VMEM)) {
1444 		PROC_UNLOCK(td->td_proc);
1445 		return (ENOMEM);
1446 	}
1447 	if (racct_set(td->td_proc, RACCT_VMEM,
1448 	    td->td_proc->p_vmspace->vm_map.size + size)) {
1449 		PROC_UNLOCK(td->td_proc);
1450 		return (ENOMEM);
1451 	}
1452 	PROC_UNLOCK(td->td_proc);
1453 
1454 	/*
1455 	 * We currently can only deal with page aligned file offsets.
1456 	 * The check is here rather than in the syscall because the
1457 	 * kernel calls this function internally for other mmaping
1458 	 * operations (such as in exec) and non-aligned offsets will
1459 	 * cause pmap inconsistencies...so we want to be sure to
1460 	 * disallow this in all cases.
1461 	 */
1462 	if (foff & PAGE_MASK)
1463 		return (EINVAL);
1464 
1465 	if ((flags & MAP_FIXED) == 0) {
1466 		fitit = TRUE;
1467 		*addr = round_page(*addr);
1468 	} else {
1469 		if (*addr != trunc_page(*addr))
1470 			return (EINVAL);
1471 		fitit = FALSE;
1472 	}
1473 	/*
1474 	 * Lookup/allocate object.
1475 	 */
1476 	switch (handle_type) {
1477 	case OBJT_DEVICE:
1478 		error = vm_mmap_cdev(td, size, prot, &maxprot, &flags,
1479 		    handle, &foff, &object);
1480 		break;
1481 	case OBJT_VNODE:
1482 		error = vm_mmap_vnode(td, size, prot, &maxprot, &flags,
1483 		    handle, &foff, &object);
1484 		break;
1485 	case OBJT_SWAP:
1486 		error = vm_mmap_shm(td, size, prot, &maxprot, &flags,
1487 		    handle, foff, &object);
1488 		break;
1489 	case OBJT_DEFAULT:
1490 		if (handle == NULL) {
1491 			error = 0;
1492 			break;
1493 		}
1494 		/* FALLTHROUGH */
1495 	default:
1496 		error = EINVAL;
1497 		break;
1498 	}
1499 	if (error)
1500 		return (error);
1501 	if (flags & MAP_ANON) {
1502 		object = NULL;
1503 		docow = 0;
1504 		/*
1505 		 * Unnamed anonymous regions always start at 0.
1506 		 */
1507 		if (handle == 0)
1508 			foff = 0;
1509 	} else if (flags & MAP_PREFAULT_READ)
1510 		docow = MAP_PREFAULT;
1511 	else
1512 		docow = MAP_PREFAULT_PARTIAL;
1513 
1514 	if ((flags & (MAP_ANON|MAP_SHARED)) == 0)
1515 		docow |= MAP_COPY_ON_WRITE;
1516 	if (flags & MAP_NOSYNC)
1517 		docow |= MAP_DISABLE_SYNCER;
1518 	if (flags & MAP_NOCORE)
1519 		docow |= MAP_DISABLE_COREDUMP;
1520 
1521 	if (flags & MAP_STACK)
1522 		rv = vm_map_stack(map, *addr, size, prot, maxprot,
1523 		    docow | MAP_STACK_GROWS_DOWN);
1524 	else if (fitit)
1525 		rv = vm_map_find(map, object, foff, addr, size,
1526 		    object != NULL && object->type == OBJT_DEVICE ?
1527 		    VMFS_ALIGNED_SPACE : VMFS_ANY_SPACE, prot, maxprot, docow);
1528 	else
1529 		rv = vm_map_fixed(map, object, foff, *addr, size,
1530 				 prot, maxprot, docow);
1531 
1532 	if (rv != KERN_SUCCESS) {
1533 		/*
1534 		 * Lose the object reference. Will destroy the
1535 		 * object if it's an unnamed anonymous mapping
1536 		 * or named anonymous without other references.
1537 		 */
1538 		vm_object_deallocate(object);
1539 	} else if (flags & MAP_SHARED) {
1540 		/*
1541 		 * Shared memory is also shared with children.
1542 		 */
1543 		rv = vm_map_inherit(map, *addr, *addr + size, VM_INHERIT_SHARE);
1544 		if (rv != KERN_SUCCESS)
1545 			(void) vm_map_remove(map, *addr, *addr + size);
1546 	}
1547 
1548 	/*
1549 	 * If the process has requested that all future mappings
1550 	 * be wired, then heed this.
1551 	 */
1552 	if ((rv == KERN_SUCCESS) && (map->flags & MAP_WIREFUTURE))
1553 		vm_map_wire(map, *addr, *addr + size,
1554 		    VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES);
1555 
1556 	return (vm_mmap_to_errno(rv));
1557 }
1558 
1559 int
1560 vm_mmap_to_errno(int rv)
1561 {
1562 
1563 	switch (rv) {
1564 	case KERN_SUCCESS:
1565 		return (0);
1566 	case KERN_INVALID_ADDRESS:
1567 	case KERN_NO_SPACE:
1568 		return (ENOMEM);
1569 	case KERN_PROTECTION_FAILURE:
1570 		return (EACCES);
1571 	default:
1572 		return (EINVAL);
1573 	}
1574 }
1575