xref: /freebsd/sys/vm/vm_mmap.c (revision f5f7c05209ca2c3748fd8b27c5e80ffad49120eb)
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/sysctl.h>
63 #include <sys/vnode.h>
64 #include <sys/fcntl.h>
65 #include <sys/file.h>
66 #include <sys/mman.h>
67 #include <sys/mount.h>
68 #include <sys/conf.h>
69 #include <sys/stat.h>
70 #include <sys/sysent.h>
71 #include <sys/vmmeter.h>
72 
73 #include <security/mac/mac_framework.h>
74 
75 #include <vm/vm.h>
76 #include <vm/vm_param.h>
77 #include <vm/pmap.h>
78 #include <vm/vm_map.h>
79 #include <vm/vm_object.h>
80 #include <vm/vm_page.h>
81 #include <vm/vm_pager.h>
82 #include <vm/vm_pageout.h>
83 #include <vm/vm_extern.h>
84 #include <vm/vm_page.h>
85 #include <vm/vnode_pager.h>
86 
87 #ifdef HWPMC_HOOKS
88 #include <sys/pmckern.h>
89 #endif
90 
91 int old_mlock = 0;
92 SYSCTL_INT(_vm, OID_AUTO, old_mlock, CTLFLAG_RW | CTLFLAG_TUN, &old_mlock, 0,
93     "Do not apply RLIMIT_MEMLOCK on mlockall");
94 TUNABLE_INT("vm.old_mlock", &old_mlock);
95 
96 #ifndef _SYS_SYSPROTO_H_
97 struct sbrk_args {
98 	int incr;
99 };
100 #endif
101 
102 static int vm_mmap_vnode(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
103     int *, struct vnode *, vm_ooffset_t *, vm_object_t *, boolean_t *);
104 static int vm_mmap_cdev(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
105     int *, struct cdev *, vm_ooffset_t *, vm_object_t *);
106 static int vm_mmap_shm(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
107     int *, struct shmfd *, vm_ooffset_t, vm_object_t *);
108 
109 /*
110  * MPSAFE
111  */
112 /* ARGSUSED */
113 int
114 sys_sbrk(td, uap)
115 	struct thread *td;
116 	struct sbrk_args *uap;
117 {
118 	/* Not yet implemented */
119 	return (EOPNOTSUPP);
120 }
121 
122 #ifndef _SYS_SYSPROTO_H_
123 struct sstk_args {
124 	int incr;
125 };
126 #endif
127 
128 /*
129  * MPSAFE
130  */
131 /* ARGSUSED */
132 int
133 sys_sstk(td, uap)
134 	struct thread *td;
135 	struct sstk_args *uap;
136 {
137 	/* Not yet implemented */
138 	return (EOPNOTSUPP);
139 }
140 
141 #if defined(COMPAT_43)
142 #ifndef _SYS_SYSPROTO_H_
143 struct getpagesize_args {
144 	int dummy;
145 };
146 #endif
147 
148 int
149 ogetpagesize(td, uap)
150 	struct thread *td;
151 	struct getpagesize_args *uap;
152 {
153 	/* MP SAFE */
154 	td->td_retval[0] = PAGE_SIZE;
155 	return (0);
156 }
157 #endif				/* COMPAT_43 */
158 
159 
160 /*
161  * Memory Map (mmap) system call.  Note that the file offset
162  * and address are allowed to be NOT page aligned, though if
163  * the MAP_FIXED flag it set, both must have the same remainder
164  * modulo the PAGE_SIZE (POSIX 1003.1b).  If the address is not
165  * page-aligned, the actual mapping starts at trunc_page(addr)
166  * and the return value is adjusted up by the page offset.
167  *
168  * Generally speaking, only character devices which are themselves
169  * memory-based, such as a video framebuffer, can be mmap'd.  Otherwise
170  * there would be no cache coherency between a descriptor and a VM mapping
171  * both to the same character device.
172  */
173 #ifndef _SYS_SYSPROTO_H_
174 struct mmap_args {
175 	void *addr;
176 	size_t len;
177 	int prot;
178 	int flags;
179 	int fd;
180 	long pad;
181 	off_t pos;
182 };
183 #endif
184 
185 /*
186  * MPSAFE
187  */
188 int
189 sys_mmap(td, uap)
190 	struct thread *td;
191 	struct mmap_args *uap;
192 {
193 #ifdef HWPMC_HOOKS
194 	struct pmckern_map_in pkm;
195 #endif
196 	struct file *fp;
197 	struct vnode *vp;
198 	vm_offset_t addr;
199 	vm_size_t size, pageoff;
200 	vm_prot_t cap_maxprot, prot, maxprot;
201 	void *handle;
202 	objtype_t handle_type;
203 	int flags, error;
204 	off_t pos;
205 	struct vmspace *vms = td->td_proc->p_vmspace;
206 	cap_rights_t rights;
207 
208 	addr = (vm_offset_t) uap->addr;
209 	size = uap->len;
210 	prot = uap->prot & VM_PROT_ALL;
211 	flags = uap->flags;
212 	pos = uap->pos;
213 
214 	fp = NULL;
215 
216 	/*
217 	 * Enforce the constraints.
218 	 * Mapping of length 0 is only allowed for old binaries.
219 	 * Anonymous mapping shall specify -1 as filedescriptor and
220 	 * zero position for new code. Be nice to ancient a.out
221 	 * binaries and correct pos for anonymous mapping, since old
222 	 * ld.so sometimes issues anonymous map requests with non-zero
223 	 * pos.
224 	 */
225 	if (!SV_CURPROC_FLAG(SV_AOUT)) {
226 		if ((uap->len == 0 && curproc->p_osrel >= P_OSREL_MAP_ANON) ||
227 		    ((flags & MAP_ANON) != 0 && (uap->fd != -1 || pos != 0)))
228 			return (EINVAL);
229 	} else {
230 		if ((flags & MAP_ANON) != 0)
231 			pos = 0;
232 	}
233 
234 	if (flags & MAP_STACK) {
235 		if ((uap->fd != -1) ||
236 		    ((prot & (PROT_READ | PROT_WRITE)) != (PROT_READ | PROT_WRITE)))
237 			return (EINVAL);
238 		flags |= MAP_ANON;
239 		pos = 0;
240 	}
241 
242 	/*
243 	 * Align the file position to a page boundary,
244 	 * and save its page offset component.
245 	 */
246 	pageoff = (pos & PAGE_MASK);
247 	pos -= pageoff;
248 
249 	/* Adjust size for rounding (on both ends). */
250 	size += pageoff;			/* low end... */
251 	size = (vm_size_t) round_page(size);	/* hi end */
252 
253 	/*
254 	 * Check for illegal addresses.  Watch out for address wrap... Note
255 	 * that VM_*_ADDRESS are not constants due to casts (argh).
256 	 */
257 	if (flags & MAP_FIXED) {
258 		/*
259 		 * The specified address must have the same remainder
260 		 * as the file offset taken modulo PAGE_SIZE, so it
261 		 * should be aligned after adjustment by pageoff.
262 		 */
263 		addr -= pageoff;
264 		if (addr & PAGE_MASK)
265 			return (EINVAL);
266 
267 		/* Address range must be all in user VM space. */
268 		if (addr < vm_map_min(&vms->vm_map) ||
269 		    addr + size > vm_map_max(&vms->vm_map))
270 			return (EINVAL);
271 		if (addr + size < addr)
272 			return (EINVAL);
273 	} else {
274 		/*
275 		 * XXX for non-fixed mappings where no hint is provided or
276 		 * the hint would fall in the potential heap space,
277 		 * place it after the end of the largest possible heap.
278 		 *
279 		 * There should really be a pmap call to determine a reasonable
280 		 * location.
281 		 */
282 		PROC_LOCK(td->td_proc);
283 		if (addr == 0 ||
284 		    (addr >= round_page((vm_offset_t)vms->vm_taddr) &&
285 		    addr < round_page((vm_offset_t)vms->vm_daddr +
286 		    lim_max(td->td_proc, RLIMIT_DATA))))
287 			addr = round_page((vm_offset_t)vms->vm_daddr +
288 			    lim_max(td->td_proc, RLIMIT_DATA));
289 		PROC_UNLOCK(td->td_proc);
290 	}
291 	if (flags & MAP_ANON) {
292 		/*
293 		 * Mapping blank space is trivial.
294 		 */
295 		handle = NULL;
296 		handle_type = OBJT_DEFAULT;
297 		maxprot = VM_PROT_ALL;
298 		cap_maxprot = VM_PROT_ALL;
299 	} else {
300 		/*
301 		 * Mapping file, get fp for validation and don't let the
302 		 * descriptor disappear on us if we block. Check capability
303 		 * rights, but also return the maximum rights to be combined
304 		 * with maxprot later.
305 		 */
306 		rights = CAP_MMAP;
307 		if (prot & PROT_READ)
308 			rights |= CAP_READ;
309 		if ((flags & MAP_SHARED) != 0) {
310 			if (prot & PROT_WRITE)
311 				rights |= CAP_WRITE;
312 		}
313 		if (prot & PROT_EXEC)
314 			rights |= CAP_MAPEXEC;
315 		if ((error = fget_mmap(td, uap->fd, rights, &cap_maxprot,
316 		    &fp)) != 0)
317 			goto done;
318 		if (fp->f_type == DTYPE_SHM) {
319 			handle = fp->f_data;
320 			handle_type = OBJT_SWAP;
321 			maxprot = VM_PROT_NONE;
322 
323 			/* FREAD should always be set. */
324 			if (fp->f_flag & FREAD)
325 				maxprot |= VM_PROT_EXECUTE | VM_PROT_READ;
326 			if (fp->f_flag & FWRITE)
327 				maxprot |= VM_PROT_WRITE;
328 			goto map;
329 		}
330 		if (fp->f_type != DTYPE_VNODE) {
331 			error = ENODEV;
332 			goto done;
333 		}
334 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
335     defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
336 		/*
337 		 * POSIX shared-memory objects are defined to have
338 		 * kernel persistence, and are not defined to support
339 		 * read(2)/write(2) -- or even open(2).  Thus, we can
340 		 * use MAP_ASYNC to trade on-disk coherence for speed.
341 		 * The shm_open(3) library routine turns on the FPOSIXSHM
342 		 * flag to request this behavior.
343 		 */
344 		if (fp->f_flag & FPOSIXSHM)
345 			flags |= MAP_NOSYNC;
346 #endif
347 		vp = fp->f_vnode;
348 		/*
349 		 * Ensure that file and memory protections are
350 		 * compatible.  Note that we only worry about
351 		 * writability if mapping is shared; in this case,
352 		 * current and max prot are dictated by the open file.
353 		 * XXX use the vnode instead?  Problem is: what
354 		 * credentials do we use for determination? What if
355 		 * proc does a setuid?
356 		 */
357 		if (vp->v_mount != NULL && vp->v_mount->mnt_flag & MNT_NOEXEC)
358 			maxprot = VM_PROT_NONE;
359 		else
360 			maxprot = VM_PROT_EXECUTE;
361 		if (fp->f_flag & FREAD) {
362 			maxprot |= VM_PROT_READ;
363 		} else if (prot & PROT_READ) {
364 			error = EACCES;
365 			goto done;
366 		}
367 		/*
368 		 * If we are sharing potential changes (either via
369 		 * MAP_SHARED or via the implicit sharing of character
370 		 * device mappings), and we are trying to get write
371 		 * permission although we opened it without asking
372 		 * for it, bail out.
373 		 */
374 		if ((flags & MAP_SHARED) != 0) {
375 			if ((fp->f_flag & FWRITE) != 0) {
376 				maxprot |= VM_PROT_WRITE;
377 			} else if ((prot & PROT_WRITE) != 0) {
378 				error = EACCES;
379 				goto done;
380 			}
381 		} else if (vp->v_type != VCHR || (fp->f_flag & FWRITE) != 0) {
382 			maxprot |= VM_PROT_WRITE;
383 			cap_maxprot |= VM_PROT_WRITE;
384 		}
385 		handle = (void *)vp;
386 		handle_type = OBJT_VNODE;
387 	}
388 map:
389 	td->td_fpop = fp;
390 	maxprot &= cap_maxprot;
391 	error = vm_mmap(&vms->vm_map, &addr, size, prot, maxprot,
392 	    flags, handle_type, handle, pos);
393 	td->td_fpop = NULL;
394 #ifdef HWPMC_HOOKS
395 	/* inform hwpmc(4) if an executable is being mapped */
396 	if (error == 0 && handle_type == OBJT_VNODE &&
397 	    (prot & PROT_EXEC)) {
398 		pkm.pm_file = handle;
399 		pkm.pm_address = (uintptr_t) addr;
400 		PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm);
401 	}
402 #endif
403 	if (error == 0)
404 		td->td_retval[0] = (register_t) (addr + pageoff);
405 done:
406 	if (fp)
407 		fdrop(fp, td);
408 
409 	return (error);
410 }
411 
412 int
413 freebsd6_mmap(struct thread *td, struct freebsd6_mmap_args *uap)
414 {
415 	struct mmap_args oargs;
416 
417 	oargs.addr = uap->addr;
418 	oargs.len = uap->len;
419 	oargs.prot = uap->prot;
420 	oargs.flags = uap->flags;
421 	oargs.fd = uap->fd;
422 	oargs.pos = uap->pos;
423 	return (sys_mmap(td, &oargs));
424 }
425 
426 #ifdef COMPAT_43
427 #ifndef _SYS_SYSPROTO_H_
428 struct ommap_args {
429 	caddr_t addr;
430 	int len;
431 	int prot;
432 	int flags;
433 	int fd;
434 	long pos;
435 };
436 #endif
437 int
438 ommap(td, uap)
439 	struct thread *td;
440 	struct ommap_args *uap;
441 {
442 	struct mmap_args nargs;
443 	static const char cvtbsdprot[8] = {
444 		0,
445 		PROT_EXEC,
446 		PROT_WRITE,
447 		PROT_EXEC | PROT_WRITE,
448 		PROT_READ,
449 		PROT_EXEC | PROT_READ,
450 		PROT_WRITE | PROT_READ,
451 		PROT_EXEC | PROT_WRITE | PROT_READ,
452 	};
453 
454 #define	OMAP_ANON	0x0002
455 #define	OMAP_COPY	0x0020
456 #define	OMAP_SHARED	0x0010
457 #define	OMAP_FIXED	0x0100
458 
459 	nargs.addr = uap->addr;
460 	nargs.len = uap->len;
461 	nargs.prot = cvtbsdprot[uap->prot & 0x7];
462 #ifdef COMPAT_FREEBSD32
463 #if defined(__amd64__) || defined(__ia64__)
464 	if (i386_read_exec && SV_PROC_FLAG(td->td_proc, SV_ILP32) &&
465 	    nargs.prot != 0)
466 		nargs.prot |= PROT_EXEC;
467 #endif
468 #endif
469 	nargs.flags = 0;
470 	if (uap->flags & OMAP_ANON)
471 		nargs.flags |= MAP_ANON;
472 	if (uap->flags & OMAP_COPY)
473 		nargs.flags |= MAP_COPY;
474 	if (uap->flags & OMAP_SHARED)
475 		nargs.flags |= MAP_SHARED;
476 	else
477 		nargs.flags |= MAP_PRIVATE;
478 	if (uap->flags & OMAP_FIXED)
479 		nargs.flags |= MAP_FIXED;
480 	nargs.fd = uap->fd;
481 	nargs.pos = uap->pos;
482 	return (sys_mmap(td, &nargs));
483 }
484 #endif				/* COMPAT_43 */
485 
486 
487 #ifndef _SYS_SYSPROTO_H_
488 struct msync_args {
489 	void *addr;
490 	size_t len;
491 	int flags;
492 };
493 #endif
494 /*
495  * MPSAFE
496  */
497 int
498 sys_msync(td, uap)
499 	struct thread *td;
500 	struct msync_args *uap;
501 {
502 	vm_offset_t addr;
503 	vm_size_t size, pageoff;
504 	int flags;
505 	vm_map_t map;
506 	int rv;
507 
508 	addr = (vm_offset_t) uap->addr;
509 	size = uap->len;
510 	flags = uap->flags;
511 
512 	pageoff = (addr & PAGE_MASK);
513 	addr -= pageoff;
514 	size += pageoff;
515 	size = (vm_size_t) round_page(size);
516 	if (addr + size < addr)
517 		return (EINVAL);
518 
519 	if ((flags & (MS_ASYNC|MS_INVALIDATE)) == (MS_ASYNC|MS_INVALIDATE))
520 		return (EINVAL);
521 
522 	map = &td->td_proc->p_vmspace->vm_map;
523 
524 	/*
525 	 * Clean the pages and interpret the return value.
526 	 */
527 	rv = vm_map_sync(map, addr, addr + size, (flags & MS_ASYNC) == 0,
528 	    (flags & MS_INVALIDATE) != 0);
529 	switch (rv) {
530 	case KERN_SUCCESS:
531 		return (0);
532 	case KERN_INVALID_ADDRESS:
533 		return (EINVAL);	/* Sun returns ENOMEM? */
534 	case KERN_INVALID_ARGUMENT:
535 		return (EBUSY);
536 	case KERN_FAILURE:
537 		return (EIO);
538 	default:
539 		return (EINVAL);
540 	}
541 }
542 
543 #ifndef _SYS_SYSPROTO_H_
544 struct munmap_args {
545 	void *addr;
546 	size_t len;
547 };
548 #endif
549 /*
550  * MPSAFE
551  */
552 int
553 sys_munmap(td, uap)
554 	struct thread *td;
555 	struct munmap_args *uap;
556 {
557 #ifdef HWPMC_HOOKS
558 	struct pmckern_map_out pkm;
559 	vm_map_entry_t entry;
560 #endif
561 	vm_offset_t addr;
562 	vm_size_t size, pageoff;
563 	vm_map_t map;
564 
565 	addr = (vm_offset_t) uap->addr;
566 	size = uap->len;
567 	if (size == 0)
568 		return (EINVAL);
569 
570 	pageoff = (addr & PAGE_MASK);
571 	addr -= pageoff;
572 	size += pageoff;
573 	size = (vm_size_t) round_page(size);
574 	if (addr + size < addr)
575 		return (EINVAL);
576 
577 	/*
578 	 * Check for illegal addresses.  Watch out for address wrap...
579 	 */
580 	map = &td->td_proc->p_vmspace->vm_map;
581 	if (addr < vm_map_min(map) || addr + size > vm_map_max(map))
582 		return (EINVAL);
583 	vm_map_lock(map);
584 #ifdef HWPMC_HOOKS
585 	/*
586 	 * Inform hwpmc if the address range being unmapped contains
587 	 * an executable region.
588 	 */
589 	pkm.pm_address = (uintptr_t) NULL;
590 	if (vm_map_lookup_entry(map, addr, &entry)) {
591 		for (;
592 		     entry != &map->header && entry->start < addr + size;
593 		     entry = entry->next) {
594 			if (vm_map_check_protection(map, entry->start,
595 				entry->end, VM_PROT_EXECUTE) == TRUE) {
596 				pkm.pm_address = (uintptr_t) addr;
597 				pkm.pm_size = (size_t) size;
598 				break;
599 			}
600 		}
601 	}
602 #endif
603 	vm_map_delete(map, addr, addr + size);
604 
605 #ifdef HWPMC_HOOKS
606 	/* downgrade the lock to prevent a LOR with the pmc-sx lock */
607 	vm_map_lock_downgrade(map);
608 	if (pkm.pm_address != (uintptr_t) NULL)
609 		PMC_CALL_HOOK(td, PMC_FN_MUNMAP, (void *) &pkm);
610 	vm_map_unlock_read(map);
611 #else
612 	vm_map_unlock(map);
613 #endif
614 	/* vm_map_delete returns nothing but KERN_SUCCESS anyway */
615 	return (0);
616 }
617 
618 #ifndef _SYS_SYSPROTO_H_
619 struct mprotect_args {
620 	const void *addr;
621 	size_t len;
622 	int prot;
623 };
624 #endif
625 /*
626  * MPSAFE
627  */
628 int
629 sys_mprotect(td, uap)
630 	struct thread *td;
631 	struct mprotect_args *uap;
632 {
633 	vm_offset_t addr;
634 	vm_size_t size, pageoff;
635 	vm_prot_t prot;
636 
637 	addr = (vm_offset_t) uap->addr;
638 	size = uap->len;
639 	prot = uap->prot & VM_PROT_ALL;
640 
641 	pageoff = (addr & PAGE_MASK);
642 	addr -= pageoff;
643 	size += pageoff;
644 	size = (vm_size_t) round_page(size);
645 	if (addr + size < addr)
646 		return (EINVAL);
647 
648 	switch (vm_map_protect(&td->td_proc->p_vmspace->vm_map, addr,
649 	    addr + size, prot, FALSE)) {
650 	case KERN_SUCCESS:
651 		return (0);
652 	case KERN_PROTECTION_FAILURE:
653 		return (EACCES);
654 	case KERN_RESOURCE_SHORTAGE:
655 		return (ENOMEM);
656 	}
657 	return (EINVAL);
658 }
659 
660 #ifndef _SYS_SYSPROTO_H_
661 struct minherit_args {
662 	void *addr;
663 	size_t len;
664 	int inherit;
665 };
666 #endif
667 /*
668  * MPSAFE
669  */
670 int
671 sys_minherit(td, uap)
672 	struct thread *td;
673 	struct minherit_args *uap;
674 {
675 	vm_offset_t addr;
676 	vm_size_t size, pageoff;
677 	vm_inherit_t inherit;
678 
679 	addr = (vm_offset_t)uap->addr;
680 	size = uap->len;
681 	inherit = uap->inherit;
682 
683 	pageoff = (addr & PAGE_MASK);
684 	addr -= pageoff;
685 	size += pageoff;
686 	size = (vm_size_t) round_page(size);
687 	if (addr + size < addr)
688 		return (EINVAL);
689 
690 	switch (vm_map_inherit(&td->td_proc->p_vmspace->vm_map, addr,
691 	    addr + size, inherit)) {
692 	case KERN_SUCCESS:
693 		return (0);
694 	case KERN_PROTECTION_FAILURE:
695 		return (EACCES);
696 	}
697 	return (EINVAL);
698 }
699 
700 #ifndef _SYS_SYSPROTO_H_
701 struct madvise_args {
702 	void *addr;
703 	size_t len;
704 	int behav;
705 };
706 #endif
707 
708 /*
709  * MPSAFE
710  */
711 int
712 sys_madvise(td, uap)
713 	struct thread *td;
714 	struct madvise_args *uap;
715 {
716 	vm_offset_t start, end;
717 	vm_map_t map;
718 	struct proc *p;
719 	int error;
720 
721 	/*
722 	 * Check for our special case, advising the swap pager we are
723 	 * "immortal."
724 	 */
725 	if (uap->behav == MADV_PROTECT) {
726 		error = priv_check(td, PRIV_VM_MADV_PROTECT);
727 		if (error == 0) {
728 			p = td->td_proc;
729 			PROC_LOCK(p);
730 			p->p_flag |= P_PROTECTED;
731 			PROC_UNLOCK(p);
732 		}
733 		return (error);
734 	}
735 	/*
736 	 * Check for illegal behavior
737 	 */
738 	if (uap->behav < 0 || uap->behav > MADV_CORE)
739 		return (EINVAL);
740 	/*
741 	 * Check for illegal addresses.  Watch out for address wrap... Note
742 	 * that VM_*_ADDRESS are not constants due to casts (argh).
743 	 */
744 	map = &td->td_proc->p_vmspace->vm_map;
745 	if ((vm_offset_t)uap->addr < vm_map_min(map) ||
746 	    (vm_offset_t)uap->addr + uap->len > vm_map_max(map))
747 		return (EINVAL);
748 	if (((vm_offset_t) uap->addr + uap->len) < (vm_offset_t) uap->addr)
749 		return (EINVAL);
750 
751 	/*
752 	 * Since this routine is only advisory, we default to conservative
753 	 * behavior.
754 	 */
755 	start = trunc_page((vm_offset_t) uap->addr);
756 	end = round_page((vm_offset_t) uap->addr + uap->len);
757 
758 	if (vm_map_madvise(map, start, end, uap->behav))
759 		return (EINVAL);
760 	return (0);
761 }
762 
763 #ifndef _SYS_SYSPROTO_H_
764 struct mincore_args {
765 	const void *addr;
766 	size_t len;
767 	char *vec;
768 };
769 #endif
770 
771 /*
772  * MPSAFE
773  */
774 int
775 sys_mincore(td, uap)
776 	struct thread *td;
777 	struct mincore_args *uap;
778 {
779 	vm_offset_t addr, first_addr;
780 	vm_offset_t end, cend;
781 	pmap_t pmap;
782 	vm_map_t map;
783 	char *vec;
784 	int error = 0;
785 	int vecindex, lastvecindex;
786 	vm_map_entry_t current;
787 	vm_map_entry_t entry;
788 	vm_object_t object;
789 	vm_paddr_t locked_pa;
790 	vm_page_t m;
791 	vm_pindex_t pindex;
792 	int mincoreinfo;
793 	unsigned int timestamp;
794 	boolean_t locked;
795 
796 	/*
797 	 * Make sure that the addresses presented are valid for user
798 	 * mode.
799 	 */
800 	first_addr = addr = trunc_page((vm_offset_t) uap->addr);
801 	end = addr + (vm_size_t)round_page(uap->len);
802 	map = &td->td_proc->p_vmspace->vm_map;
803 	if (end > vm_map_max(map) || end < addr)
804 		return (ENOMEM);
805 
806 	/*
807 	 * Address of byte vector
808 	 */
809 	vec = uap->vec;
810 
811 	pmap = vmspace_pmap(td->td_proc->p_vmspace);
812 
813 	vm_map_lock_read(map);
814 RestartScan:
815 	timestamp = map->timestamp;
816 
817 	if (!vm_map_lookup_entry(map, addr, &entry)) {
818 		vm_map_unlock_read(map);
819 		return (ENOMEM);
820 	}
821 
822 	/*
823 	 * Do this on a map entry basis so that if the pages are not
824 	 * in the current processes address space, we can easily look
825 	 * up the pages elsewhere.
826 	 */
827 	lastvecindex = -1;
828 	for (current = entry;
829 	    (current != &map->header) && (current->start < end);
830 	    current = current->next) {
831 
832 		/*
833 		 * check for contiguity
834 		 */
835 		if (current->end < end &&
836 		    (entry->next == &map->header ||
837 		     current->next->start > current->end)) {
838 			vm_map_unlock_read(map);
839 			return (ENOMEM);
840 		}
841 
842 		/*
843 		 * ignore submaps (for now) or null objects
844 		 */
845 		if ((current->eflags & MAP_ENTRY_IS_SUB_MAP) ||
846 			current->object.vm_object == NULL)
847 			continue;
848 
849 		/*
850 		 * limit this scan to the current map entry and the
851 		 * limits for the mincore call
852 		 */
853 		if (addr < current->start)
854 			addr = current->start;
855 		cend = current->end;
856 		if (cend > end)
857 			cend = end;
858 
859 		/*
860 		 * scan this entry one page at a time
861 		 */
862 		while (addr < cend) {
863 			/*
864 			 * Check pmap first, it is likely faster, also
865 			 * it can provide info as to whether we are the
866 			 * one referencing or modifying the page.
867 			 */
868 			object = NULL;
869 			locked_pa = 0;
870 		retry:
871 			m = NULL;
872 			mincoreinfo = pmap_mincore(pmap, addr, &locked_pa);
873 			if (locked_pa != 0) {
874 				/*
875 				 * The page is mapped by this process but not
876 				 * both accessed and modified.  It is also
877 				 * managed.  Acquire the object lock so that
878 				 * other mappings might be examined.
879 				 */
880 				m = PHYS_TO_VM_PAGE(locked_pa);
881 				if (m->object != object) {
882 					if (object != NULL)
883 						VM_OBJECT_UNLOCK(object);
884 					object = m->object;
885 					locked = VM_OBJECT_TRYLOCK(object);
886 					vm_page_unlock(m);
887 					if (!locked) {
888 						VM_OBJECT_LOCK(object);
889 						vm_page_lock(m);
890 						goto retry;
891 					}
892 				} else
893 					vm_page_unlock(m);
894 				KASSERT(m->valid == VM_PAGE_BITS_ALL,
895 				    ("mincore: page %p is mapped but invalid",
896 				    m));
897 			} else if (mincoreinfo == 0) {
898 				/*
899 				 * The page is not mapped by this process.  If
900 				 * the object implements managed pages, then
901 				 * determine if the page is resident so that
902 				 * the mappings might be examined.
903 				 */
904 				if (current->object.vm_object != object) {
905 					if (object != NULL)
906 						VM_OBJECT_UNLOCK(object);
907 					object = current->object.vm_object;
908 					VM_OBJECT_LOCK(object);
909 				}
910 				if (object->type == OBJT_DEFAULT ||
911 				    object->type == OBJT_SWAP ||
912 				    object->type == OBJT_VNODE) {
913 					pindex = OFF_TO_IDX(current->offset +
914 					    (addr - current->start));
915 					m = vm_page_lookup(object, pindex);
916 					if (m == NULL &&
917 					    vm_page_is_cached(object, pindex))
918 						mincoreinfo = MINCORE_INCORE;
919 					if (m != NULL && m->valid == 0)
920 						m = NULL;
921 					if (m != NULL)
922 						mincoreinfo = MINCORE_INCORE;
923 				}
924 			}
925 			if (m != NULL) {
926 				/* Examine other mappings to the page. */
927 				if (m->dirty == 0 && pmap_is_modified(m))
928 					vm_page_dirty(m);
929 				if (m->dirty != 0)
930 					mincoreinfo |= MINCORE_MODIFIED_OTHER;
931 				/*
932 				 * The first test for PGA_REFERENCED is an
933 				 * optimization.  The second test is
934 				 * required because a concurrent pmap
935 				 * operation could clear the last reference
936 				 * and set PGA_REFERENCED before the call to
937 				 * pmap_is_referenced().
938 				 */
939 				if ((m->aflags & PGA_REFERENCED) != 0 ||
940 				    pmap_is_referenced(m) ||
941 				    (m->aflags & PGA_REFERENCED) != 0)
942 					mincoreinfo |= MINCORE_REFERENCED_OTHER;
943 			}
944 			if (object != NULL)
945 				VM_OBJECT_UNLOCK(object);
946 
947 			/*
948 			 * subyte may page fault.  In case it needs to modify
949 			 * the map, we release the lock.
950 			 */
951 			vm_map_unlock_read(map);
952 
953 			/*
954 			 * calculate index into user supplied byte vector
955 			 */
956 			vecindex = OFF_TO_IDX(addr - first_addr);
957 
958 			/*
959 			 * If we have skipped map entries, we need to make sure that
960 			 * the byte vector is zeroed for those skipped entries.
961 			 */
962 			while ((lastvecindex + 1) < vecindex) {
963 				error = subyte(vec + lastvecindex, 0);
964 				if (error) {
965 					error = EFAULT;
966 					goto done2;
967 				}
968 				++lastvecindex;
969 			}
970 
971 			/*
972 			 * Pass the page information to the user
973 			 */
974 			error = subyte(vec + vecindex, mincoreinfo);
975 			if (error) {
976 				error = EFAULT;
977 				goto done2;
978 			}
979 
980 			/*
981 			 * If the map has changed, due to the subyte, the previous
982 			 * output may be invalid.
983 			 */
984 			vm_map_lock_read(map);
985 			if (timestamp != map->timestamp)
986 				goto RestartScan;
987 
988 			lastvecindex = vecindex;
989 			addr += PAGE_SIZE;
990 		}
991 	}
992 
993 	/*
994 	 * subyte may page fault.  In case it needs to modify
995 	 * the map, we release the lock.
996 	 */
997 	vm_map_unlock_read(map);
998 
999 	/*
1000 	 * Zero the last entries in the byte vector.
1001 	 */
1002 	vecindex = OFF_TO_IDX(end - first_addr);
1003 	while ((lastvecindex + 1) < vecindex) {
1004 		error = subyte(vec + lastvecindex, 0);
1005 		if (error) {
1006 			error = EFAULT;
1007 			goto done2;
1008 		}
1009 		++lastvecindex;
1010 	}
1011 
1012 	/*
1013 	 * If the map has changed, due to the subyte, the previous
1014 	 * output may be invalid.
1015 	 */
1016 	vm_map_lock_read(map);
1017 	if (timestamp != map->timestamp)
1018 		goto RestartScan;
1019 	vm_map_unlock_read(map);
1020 done2:
1021 	return (error);
1022 }
1023 
1024 #ifndef _SYS_SYSPROTO_H_
1025 struct mlock_args {
1026 	const void *addr;
1027 	size_t len;
1028 };
1029 #endif
1030 /*
1031  * MPSAFE
1032  */
1033 int
1034 sys_mlock(td, uap)
1035 	struct thread *td;
1036 	struct mlock_args *uap;
1037 {
1038 	struct proc *proc;
1039 	vm_offset_t addr, end, last, start;
1040 	vm_size_t npages, size;
1041 	vm_map_t map;
1042 	unsigned long nsize;
1043 	int error;
1044 
1045 	error = priv_check(td, PRIV_VM_MLOCK);
1046 	if (error)
1047 		return (error);
1048 	addr = (vm_offset_t)uap->addr;
1049 	size = uap->len;
1050 	last = addr + size;
1051 	start = trunc_page(addr);
1052 	end = round_page(last);
1053 	if (last < addr || end < addr)
1054 		return (EINVAL);
1055 	npages = atop(end - start);
1056 	if (npages > vm_page_max_wired)
1057 		return (ENOMEM);
1058 	proc = td->td_proc;
1059 	map = &proc->p_vmspace->vm_map;
1060 	PROC_LOCK(proc);
1061 	nsize = ptoa(npages + pmap_wired_count(map->pmap));
1062 	if (nsize > lim_cur(proc, RLIMIT_MEMLOCK)) {
1063 		PROC_UNLOCK(proc);
1064 		return (ENOMEM);
1065 	}
1066 	PROC_UNLOCK(proc);
1067 	if (npages + cnt.v_wire_count > vm_page_max_wired)
1068 		return (EAGAIN);
1069 #ifdef RACCT
1070 	PROC_LOCK(proc);
1071 	error = racct_set(proc, RACCT_MEMLOCK, nsize);
1072 	PROC_UNLOCK(proc);
1073 	if (error != 0)
1074 		return (ENOMEM);
1075 #endif
1076 	error = vm_map_wire(map, start, end,
1077 	    VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
1078 #ifdef RACCT
1079 	if (error != KERN_SUCCESS) {
1080 		PROC_LOCK(proc);
1081 		racct_set(proc, RACCT_MEMLOCK,
1082 		    ptoa(pmap_wired_count(map->pmap)));
1083 		PROC_UNLOCK(proc);
1084 	}
1085 #endif
1086 	return (error == KERN_SUCCESS ? 0 : ENOMEM);
1087 }
1088 
1089 #ifndef _SYS_SYSPROTO_H_
1090 struct mlockall_args {
1091 	int	how;
1092 };
1093 #endif
1094 
1095 /*
1096  * MPSAFE
1097  */
1098 int
1099 sys_mlockall(td, uap)
1100 	struct thread *td;
1101 	struct mlockall_args *uap;
1102 {
1103 	vm_map_t map;
1104 	int error;
1105 
1106 	map = &td->td_proc->p_vmspace->vm_map;
1107 	error = priv_check(td, PRIV_VM_MLOCK);
1108 	if (error)
1109 		return (error);
1110 
1111 	if ((uap->how == 0) || ((uap->how & ~(MCL_CURRENT|MCL_FUTURE)) != 0))
1112 		return (EINVAL);
1113 
1114 	/*
1115 	 * If wiring all pages in the process would cause it to exceed
1116 	 * a hard resource limit, return ENOMEM.
1117 	 */
1118 	if (!old_mlock && uap->how & MCL_CURRENT) {
1119 		PROC_LOCK(td->td_proc);
1120 		if (map->size > lim_cur(td->td_proc, RLIMIT_MEMLOCK)) {
1121 			PROC_UNLOCK(td->td_proc);
1122 			return (ENOMEM);
1123 		}
1124 		PROC_UNLOCK(td->td_proc);
1125 	}
1126 #ifdef RACCT
1127 	PROC_LOCK(td->td_proc);
1128 	error = racct_set(td->td_proc, RACCT_MEMLOCK, map->size);
1129 	PROC_UNLOCK(td->td_proc);
1130 	if (error != 0)
1131 		return (ENOMEM);
1132 #endif
1133 
1134 	if (uap->how & MCL_FUTURE) {
1135 		vm_map_lock(map);
1136 		vm_map_modflags(map, MAP_WIREFUTURE, 0);
1137 		vm_map_unlock(map);
1138 		error = 0;
1139 	}
1140 
1141 	if (uap->how & MCL_CURRENT) {
1142 		/*
1143 		 * P1003.1-2001 mandates that all currently mapped pages
1144 		 * will be memory resident and locked (wired) upon return
1145 		 * from mlockall(). vm_map_wire() will wire pages, by
1146 		 * calling vm_fault_wire() for each page in the region.
1147 		 */
1148 		error = vm_map_wire(map, vm_map_min(map), vm_map_max(map),
1149 		    VM_MAP_WIRE_USER|VM_MAP_WIRE_HOLESOK);
1150 		error = (error == KERN_SUCCESS ? 0 : EAGAIN);
1151 	}
1152 #ifdef RACCT
1153 	if (error != KERN_SUCCESS) {
1154 		PROC_LOCK(td->td_proc);
1155 		racct_set(td->td_proc, RACCT_MEMLOCK,
1156 		    ptoa(pmap_wired_count(map->pmap)));
1157 		PROC_UNLOCK(td->td_proc);
1158 	}
1159 #endif
1160 
1161 	return (error);
1162 }
1163 
1164 #ifndef _SYS_SYSPROTO_H_
1165 struct munlockall_args {
1166 	register_t dummy;
1167 };
1168 #endif
1169 
1170 /*
1171  * MPSAFE
1172  */
1173 int
1174 sys_munlockall(td, uap)
1175 	struct thread *td;
1176 	struct munlockall_args *uap;
1177 {
1178 	vm_map_t map;
1179 	int error;
1180 
1181 	map = &td->td_proc->p_vmspace->vm_map;
1182 	error = priv_check(td, PRIV_VM_MUNLOCK);
1183 	if (error)
1184 		return (error);
1185 
1186 	/* Clear the MAP_WIREFUTURE flag from this vm_map. */
1187 	vm_map_lock(map);
1188 	vm_map_modflags(map, 0, MAP_WIREFUTURE);
1189 	vm_map_unlock(map);
1190 
1191 	/* Forcibly unwire all pages. */
1192 	error = vm_map_unwire(map, vm_map_min(map), vm_map_max(map),
1193 	    VM_MAP_WIRE_USER|VM_MAP_WIRE_HOLESOK);
1194 #ifdef RACCT
1195 	if (error == KERN_SUCCESS) {
1196 		PROC_LOCK(td->td_proc);
1197 		racct_set(td->td_proc, RACCT_MEMLOCK, 0);
1198 		PROC_UNLOCK(td->td_proc);
1199 	}
1200 #endif
1201 
1202 	return (error);
1203 }
1204 
1205 #ifndef _SYS_SYSPROTO_H_
1206 struct munlock_args {
1207 	const void *addr;
1208 	size_t len;
1209 };
1210 #endif
1211 /*
1212  * MPSAFE
1213  */
1214 int
1215 sys_munlock(td, uap)
1216 	struct thread *td;
1217 	struct munlock_args *uap;
1218 {
1219 	vm_offset_t addr, end, last, start;
1220 	vm_size_t size;
1221 	int error;
1222 
1223 	error = priv_check(td, PRIV_VM_MUNLOCK);
1224 	if (error)
1225 		return (error);
1226 	addr = (vm_offset_t)uap->addr;
1227 	size = uap->len;
1228 	last = addr + size;
1229 	start = trunc_page(addr);
1230 	end = round_page(last);
1231 	if (last < addr || end < addr)
1232 		return (EINVAL);
1233 	error = vm_map_unwire(&td->td_proc->p_vmspace->vm_map, start, end,
1234 	    VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
1235 #ifdef RACCT
1236 	if (error == KERN_SUCCESS) {
1237 		PROC_LOCK(td->td_proc);
1238 		racct_sub(td->td_proc, RACCT_MEMLOCK, ptoa(end - start));
1239 		PROC_UNLOCK(td->td_proc);
1240 	}
1241 #endif
1242 	return (error == KERN_SUCCESS ? 0 : ENOMEM);
1243 }
1244 
1245 /*
1246  * vm_mmap_vnode()
1247  *
1248  * Helper function for vm_mmap.  Perform sanity check specific for mmap
1249  * operations on vnodes.
1250  *
1251  * For VCHR vnodes, the vnode lock is held over the call to
1252  * vm_mmap_cdev() to keep vp->v_rdev valid.
1253  */
1254 int
1255 vm_mmap_vnode(struct thread *td, vm_size_t objsize,
1256     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
1257     struct vnode *vp, vm_ooffset_t *foffp, vm_object_t *objp,
1258     boolean_t *writecounted)
1259 {
1260 	struct vattr va;
1261 	vm_object_t obj;
1262 	vm_offset_t foff;
1263 	struct mount *mp;
1264 	struct ucred *cred;
1265 	int error, flags, locktype;
1266 
1267 	mp = vp->v_mount;
1268 	cred = td->td_ucred;
1269 	if ((*maxprotp & VM_PROT_WRITE) && (*flagsp & MAP_SHARED))
1270 		locktype = LK_EXCLUSIVE;
1271 	else
1272 		locktype = LK_SHARED;
1273 	if ((error = vget(vp, locktype, td)) != 0)
1274 		return (error);
1275 	foff = *foffp;
1276 	flags = *flagsp;
1277 	obj = vp->v_object;
1278 	if (vp->v_type == VREG) {
1279 		/*
1280 		 * Get the proper underlying object
1281 		 */
1282 		if (obj == NULL) {
1283 			error = EINVAL;
1284 			goto done;
1285 		}
1286 		if (obj->handle != vp) {
1287 			vput(vp);
1288 			vp = (struct vnode *)obj->handle;
1289 			/*
1290 			 * Bypass filesystems obey the mpsafety of the
1291 			 * underlying fs.
1292 			 */
1293 			error = vget(vp, locktype, td);
1294 			if (error != 0)
1295 				return (error);
1296 		}
1297 		if (locktype == LK_EXCLUSIVE) {
1298 			*writecounted = TRUE;
1299 			vnode_pager_update_writecount(obj, 0, objsize);
1300 		}
1301 	} else if (vp->v_type == VCHR) {
1302 		error = vm_mmap_cdev(td, objsize, prot, maxprotp, flagsp,
1303 		    vp->v_rdev, foffp, objp);
1304 		if (error == 0)
1305 			goto mark_atime;
1306 		goto done;
1307 	} else {
1308 		error = EINVAL;
1309 		goto done;
1310 	}
1311 	if ((error = VOP_GETATTR(vp, &va, cred)))
1312 		goto done;
1313 #ifdef MAC
1314 	error = mac_vnode_check_mmap(cred, vp, prot, flags);
1315 	if (error != 0)
1316 		goto done;
1317 #endif
1318 	if ((flags & MAP_SHARED) != 0) {
1319 		if ((va.va_flags & (SF_SNAPSHOT|IMMUTABLE|APPEND)) != 0) {
1320 			if (prot & PROT_WRITE) {
1321 				error = EPERM;
1322 				goto done;
1323 			}
1324 			*maxprotp &= ~VM_PROT_WRITE;
1325 		}
1326 	}
1327 	/*
1328 	 * If it is a regular file without any references
1329 	 * we do not need to sync it.
1330 	 * Adjust object size to be the size of actual file.
1331 	 */
1332 	objsize = round_page(va.va_size);
1333 	if (va.va_nlink == 0)
1334 		flags |= MAP_NOSYNC;
1335 	obj = vm_pager_allocate(OBJT_VNODE, vp, objsize, prot, foff, cred);
1336 	if (obj == NULL) {
1337 		error = ENOMEM;
1338 		goto done;
1339 	}
1340 	*objp = obj;
1341 	*flagsp = flags;
1342 
1343 mark_atime:
1344 	vfs_mark_atime(vp, cred);
1345 
1346 done:
1347 	vput(vp);
1348 	return (error);
1349 }
1350 
1351 /*
1352  * vm_mmap_cdev()
1353  *
1354  * MPSAFE
1355  *
1356  * Helper function for vm_mmap.  Perform sanity check specific for mmap
1357  * operations on cdevs.
1358  */
1359 int
1360 vm_mmap_cdev(struct thread *td, vm_size_t objsize,
1361     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
1362     struct cdev *cdev, vm_ooffset_t *foff, vm_object_t *objp)
1363 {
1364 	vm_object_t obj;
1365 	struct cdevsw *dsw;
1366 	int error, flags, ref;
1367 
1368 	flags = *flagsp;
1369 
1370 	dsw = dev_refthread(cdev, &ref);
1371 	if (dsw == NULL)
1372 		return (ENXIO);
1373 	if (dsw->d_flags & D_MMAP_ANON) {
1374 		dev_relthread(cdev, ref);
1375 		*maxprotp = VM_PROT_ALL;
1376 		*flagsp |= MAP_ANON;
1377 		return (0);
1378 	}
1379 	/*
1380 	 * cdevs do not provide private mappings of any kind.
1381 	 */
1382 	if ((*maxprotp & VM_PROT_WRITE) == 0 &&
1383 	    (prot & PROT_WRITE) != 0) {
1384 		dev_relthread(cdev, ref);
1385 		return (EACCES);
1386 	}
1387 	if (flags & (MAP_PRIVATE|MAP_COPY)) {
1388 		dev_relthread(cdev, ref);
1389 		return (EINVAL);
1390 	}
1391 	/*
1392 	 * Force device mappings to be shared.
1393 	 */
1394 	flags |= MAP_SHARED;
1395 #ifdef MAC_XXX
1396 	error = mac_cdev_check_mmap(td->td_ucred, cdev, prot);
1397 	if (error != 0) {
1398 		dev_relthread(cdev, ref);
1399 		return (error);
1400 	}
1401 #endif
1402 	/*
1403 	 * First, try d_mmap_single().  If that is not implemented
1404 	 * (returns ENODEV), fall back to using the device pager.
1405 	 * Note that d_mmap_single() must return a reference to the
1406 	 * object (it needs to bump the reference count of the object
1407 	 * it returns somehow).
1408 	 *
1409 	 * XXX assumes VM_PROT_* == PROT_*
1410 	 */
1411 	error = dsw->d_mmap_single(cdev, foff, objsize, objp, (int)prot);
1412 	dev_relthread(cdev, ref);
1413 	if (error != ENODEV)
1414 		return (error);
1415 	obj = vm_pager_allocate(OBJT_DEVICE, cdev, objsize, prot, *foff,
1416 	    td->td_ucred);
1417 	if (obj == NULL)
1418 		return (EINVAL);
1419 	*objp = obj;
1420 	*flagsp = flags;
1421 	return (0);
1422 }
1423 
1424 /*
1425  * vm_mmap_shm()
1426  *
1427  * MPSAFE
1428  *
1429  * Helper function for vm_mmap.  Perform sanity check specific for mmap
1430  * operations on shm file descriptors.
1431  */
1432 int
1433 vm_mmap_shm(struct thread *td, vm_size_t objsize,
1434     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
1435     struct shmfd *shmfd, vm_ooffset_t foff, vm_object_t *objp)
1436 {
1437 	int error;
1438 
1439 	if ((*flagsp & MAP_SHARED) != 0 &&
1440 	    (*maxprotp & VM_PROT_WRITE) == 0 &&
1441 	    (prot & PROT_WRITE) != 0)
1442 		return (EACCES);
1443 #ifdef MAC
1444 	error = mac_posixshm_check_mmap(td->td_ucred, shmfd, prot, *flagsp);
1445 	if (error != 0)
1446 		return (error);
1447 #endif
1448 	error = shm_mmap(shmfd, objsize, foff, objp);
1449 	if (error)
1450 		return (error);
1451 	return (0);
1452 }
1453 
1454 /*
1455  * vm_mmap()
1456  *
1457  * MPSAFE
1458  *
1459  * Internal version of mmap.  Currently used by mmap, exec, and sys5
1460  * shared memory.  Handle is either a vnode pointer or NULL for MAP_ANON.
1461  */
1462 int
1463 vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot,
1464 	vm_prot_t maxprot, int flags,
1465 	objtype_t handle_type, void *handle,
1466 	vm_ooffset_t foff)
1467 {
1468 	boolean_t fitit;
1469 	vm_object_t object = NULL;
1470 	struct thread *td = curthread;
1471 	int docow, error, rv;
1472 	boolean_t writecounted;
1473 
1474 	if (size == 0)
1475 		return (0);
1476 
1477 	size = round_page(size);
1478 
1479 	if (map == &td->td_proc->p_vmspace->vm_map) {
1480 		PROC_LOCK(td->td_proc);
1481 		if (map->size + size > lim_cur(td->td_proc, RLIMIT_VMEM)) {
1482 			PROC_UNLOCK(td->td_proc);
1483 			return (ENOMEM);
1484 		}
1485 		if (racct_set(td->td_proc, RACCT_VMEM, map->size + size)) {
1486 			PROC_UNLOCK(td->td_proc);
1487 			return (ENOMEM);
1488 		}
1489 		if (!old_mlock && map->flags & MAP_WIREFUTURE) {
1490 			if (ptoa(pmap_wired_count(map->pmap)) + size >
1491 			    lim_cur(td->td_proc, RLIMIT_MEMLOCK)) {
1492 				racct_set_force(td->td_proc, RACCT_VMEM,
1493 				    map->size);
1494 				PROC_UNLOCK(td->td_proc);
1495 				return (ENOMEM);
1496 			}
1497 			error = racct_set(td->td_proc, RACCT_MEMLOCK,
1498 			    ptoa(pmap_wired_count(map->pmap)) + size);
1499 			if (error != 0) {
1500 				racct_set_force(td->td_proc, RACCT_VMEM,
1501 				    map->size);
1502 				PROC_UNLOCK(td->td_proc);
1503 				return (error);
1504 			}
1505 		}
1506 		PROC_UNLOCK(td->td_proc);
1507 	}
1508 
1509 	/*
1510 	 * We currently can only deal with page aligned file offsets.
1511 	 * The check is here rather than in the syscall because the
1512 	 * kernel calls this function internally for other mmaping
1513 	 * operations (such as in exec) and non-aligned offsets will
1514 	 * cause pmap inconsistencies...so we want to be sure to
1515 	 * disallow this in all cases.
1516 	 */
1517 	if (foff & PAGE_MASK)
1518 		return (EINVAL);
1519 
1520 	if ((flags & MAP_FIXED) == 0) {
1521 		fitit = TRUE;
1522 		*addr = round_page(*addr);
1523 	} else {
1524 		if (*addr != trunc_page(*addr))
1525 			return (EINVAL);
1526 		fitit = FALSE;
1527 	}
1528 	writecounted = FALSE;
1529 
1530 	/*
1531 	 * Lookup/allocate object.
1532 	 */
1533 	switch (handle_type) {
1534 	case OBJT_DEVICE:
1535 		error = vm_mmap_cdev(td, size, prot, &maxprot, &flags,
1536 		    handle, &foff, &object);
1537 		break;
1538 	case OBJT_VNODE:
1539 		error = vm_mmap_vnode(td, size, prot, &maxprot, &flags,
1540 		    handle, &foff, &object, &writecounted);
1541 		break;
1542 	case OBJT_SWAP:
1543 		error = vm_mmap_shm(td, size, prot, &maxprot, &flags,
1544 		    handle, foff, &object);
1545 		break;
1546 	case OBJT_DEFAULT:
1547 		if (handle == NULL) {
1548 			error = 0;
1549 			break;
1550 		}
1551 		/* FALLTHROUGH */
1552 	default:
1553 		error = EINVAL;
1554 		break;
1555 	}
1556 	if (error)
1557 		return (error);
1558 	if (flags & MAP_ANON) {
1559 		object = NULL;
1560 		docow = 0;
1561 		/*
1562 		 * Unnamed anonymous regions always start at 0.
1563 		 */
1564 		if (handle == 0)
1565 			foff = 0;
1566 	} else if (flags & MAP_PREFAULT_READ)
1567 		docow = MAP_PREFAULT;
1568 	else
1569 		docow = MAP_PREFAULT_PARTIAL;
1570 
1571 	if ((flags & (MAP_ANON|MAP_SHARED)) == 0)
1572 		docow |= MAP_COPY_ON_WRITE;
1573 	if (flags & MAP_NOSYNC)
1574 		docow |= MAP_DISABLE_SYNCER;
1575 	if (flags & MAP_NOCORE)
1576 		docow |= MAP_DISABLE_COREDUMP;
1577 	/* Shared memory is also shared with children. */
1578 	if (flags & MAP_SHARED)
1579 		docow |= MAP_INHERIT_SHARE;
1580 	if (writecounted)
1581 		docow |= MAP_VN_WRITECOUNT;
1582 
1583 	if (flags & MAP_STACK)
1584 		rv = vm_map_stack(map, *addr, size, prot, maxprot,
1585 		    docow | MAP_STACK_GROWS_DOWN);
1586 	else if (fitit)
1587 		rv = vm_map_find(map, object, foff, addr, size,
1588 		    object != NULL && object->type == OBJT_DEVICE ?
1589 		    VMFS_ALIGNED_SPACE : VMFS_ANY_SPACE, prot, maxprot, docow);
1590 	else
1591 		rv = vm_map_fixed(map, object, foff, *addr, size,
1592 				 prot, maxprot, docow);
1593 
1594 	if (rv == KERN_SUCCESS) {
1595 		/*
1596 		 * If the process has requested that all future mappings
1597 		 * be wired, then heed this.
1598 		 */
1599 		if (map->flags & MAP_WIREFUTURE) {
1600 			vm_map_wire(map, *addr, *addr + size,
1601 			    VM_MAP_WIRE_USER | ((flags & MAP_STACK) ?
1602 			    VM_MAP_WIRE_HOLESOK : VM_MAP_WIRE_NOHOLES));
1603 		}
1604 	} else {
1605 		/*
1606 		 * If this mapping was accounted for in the vnode's
1607 		 * writecount, then undo that now.
1608 		 */
1609 		if (writecounted)
1610 			vnode_pager_release_writecount(object, 0, size);
1611 		/*
1612 		 * Lose the object reference.  Will destroy the
1613 		 * object if it's an unnamed anonymous mapping
1614 		 * or named anonymous without other references.
1615 		 */
1616 		vm_object_deallocate(object);
1617 	}
1618 	return (vm_mmap_to_errno(rv));
1619 }
1620 
1621 /*
1622  * Translate a Mach VM return code to zero on success or the appropriate errno
1623  * on failure.
1624  */
1625 int
1626 vm_mmap_to_errno(int rv)
1627 {
1628 
1629 	switch (rv) {
1630 	case KERN_SUCCESS:
1631 		return (0);
1632 	case KERN_INVALID_ADDRESS:
1633 	case KERN_NO_SPACE:
1634 		return (ENOMEM);
1635 	case KERN_PROTECTION_FAILURE:
1636 		return (EACCES);
1637 	default:
1638 		return (EINVAL);
1639 	}
1640 }
1641