The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_mmap.c

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    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: releng/8.0/sys/vm/vm_mmap.c 197431 2009-09-23 13:49:41Z kib $");
   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/kernel.h>
   52 #include <sys/lock.h>
   53 #include <sys/mutex.h>
   54 #include <sys/sysproto.h>
   55 #include <sys/filedesc.h>
   56 #include <sys/priv.h>
   57 #include <sys/proc.h>
   58 #include <sys/resource.h>
   59 #include <sys/resourcevar.h>
   60 #include <sys/vnode.h>
   61 #include <sys/fcntl.h>
   62 #include <sys/file.h>
   63 #include <sys/mman.h>
   64 #include <sys/mount.h>
   65 #include <sys/conf.h>
   66 #include <sys/stat.h>
   67 #include <sys/sysent.h>
   68 #include <sys/vmmeter.h>
   69 #include <sys/sysctl.h>
   70 
   71 #include <security/mac/mac_framework.h>
   72 
   73 #include <vm/vm.h>
   74 #include <vm/vm_param.h>
   75 #include <vm/pmap.h>
   76 #include <vm/vm_map.h>
   77 #include <vm/vm_object.h>
   78 #include <vm/vm_page.h>
   79 #include <vm/vm_pager.h>
   80 #include <vm/vm_pageout.h>
   81 #include <vm/vm_extern.h>
   82 #include <vm/vm_page.h>
   83 #include <vm/vm_kern.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 max_proc_mmap;
   96 SYSCTL_INT(_vm, OID_AUTO, max_proc_mmap, CTLFLAG_RW, &max_proc_mmap, 0,
   97     "Maximum number of memory-mapped files per process");
   98 
   99 /*
  100  * Set the maximum number of vm_map_entry structures per process.  Roughly
  101  * speaking vm_map_entry structures are tiny, so allowing them to eat 1/100
  102  * of our KVM malloc space still results in generous limits.  We want a
  103  * default that is good enough to prevent the kernel running out of resources
  104  * if attacked from compromised user account but generous enough such that
  105  * multi-threaded processes are not unduly inconvenienced.
  106  */
  107 static void vmmapentry_rsrc_init(void *);
  108 SYSINIT(vmmersrc, SI_SUB_KVM_RSRC, SI_ORDER_FIRST, vmmapentry_rsrc_init,
  109     NULL);
  110 
  111 static void
  112 vmmapentry_rsrc_init(dummy)
  113         void *dummy;
  114 {
  115     max_proc_mmap = vm_kmem_size / sizeof(struct vm_map_entry);
  116     max_proc_mmap /= 100;
  117 }
  118 
  119 static int vm_mmap_vnode(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
  120     int *, struct vnode *, vm_ooffset_t *, vm_object_t *);
  121 static int vm_mmap_cdev(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
  122     int *, struct cdev *, vm_ooffset_t *, vm_object_t *);
  123 static int vm_mmap_shm(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
  124     int *, struct shmfd *, vm_ooffset_t, vm_object_t *);
  125 
  126 /*
  127  * MPSAFE
  128  */
  129 /* ARGSUSED */
  130 int
  131 sbrk(td, uap)
  132         struct thread *td;
  133         struct sbrk_args *uap;
  134 {
  135         /* Not yet implemented */
  136         return (EOPNOTSUPP);
  137 }
  138 
  139 #ifndef _SYS_SYSPROTO_H_
  140 struct sstk_args {
  141         int incr;
  142 };
  143 #endif
  144 
  145 /*
  146  * MPSAFE
  147  */
  148 /* ARGSUSED */
  149 int
  150 sstk(td, uap)
  151         struct thread *td;
  152         struct sstk_args *uap;
  153 {
  154         /* Not yet implemented */
  155         return (EOPNOTSUPP);
  156 }
  157 
  158 #if defined(COMPAT_43)
  159 #ifndef _SYS_SYSPROTO_H_
  160 struct getpagesize_args {
  161         int dummy;
  162 };
  163 #endif
  164 
  165 /* ARGSUSED */
  166 int
  167 ogetpagesize(td, uap)
  168         struct thread *td;
  169         struct getpagesize_args *uap;
  170 {
  171         /* MP SAFE */
  172         td->td_retval[0] = PAGE_SIZE;
  173         return (0);
  174 }
  175 #endif                          /* COMPAT_43 */
  176 
  177 
  178 /*
  179  * Memory Map (mmap) system call.  Note that the file offset
  180  * and address are allowed to be NOT page aligned, though if
  181  * the MAP_FIXED flag it set, both must have the same remainder
  182  * modulo the PAGE_SIZE (POSIX 1003.1b).  If the address is not
  183  * page-aligned, the actual mapping starts at trunc_page(addr)
  184  * and the return value is adjusted up by the page offset.
  185  *
  186  * Generally speaking, only character devices which are themselves
  187  * memory-based, such as a video framebuffer, can be mmap'd.  Otherwise
  188  * there would be no cache coherency between a descriptor and a VM mapping
  189  * both to the same character device.
  190  */
  191 #ifndef _SYS_SYSPROTO_H_
  192 struct mmap_args {
  193         void *addr;
  194         size_t len;
  195         int prot;
  196         int flags;
  197         int fd;
  198         long pad;
  199         off_t pos;
  200 };
  201 #endif
  202 
  203 /*
  204  * MPSAFE
  205  */
  206 int
  207 mmap(td, uap)
  208         struct thread *td;
  209         struct mmap_args *uap;
  210 {
  211 #ifdef HWPMC_HOOKS
  212         struct pmckern_map_in pkm;
  213 #endif
  214         struct file *fp;
  215         struct vnode *vp;
  216         vm_offset_t addr;
  217         vm_size_t size, pageoff;
  218         vm_prot_t prot, maxprot;
  219         void *handle;
  220         objtype_t handle_type;
  221         int flags, error;
  222         off_t pos;
  223         struct vmspace *vms = td->td_proc->p_vmspace;
  224 
  225         addr = (vm_offset_t) uap->addr;
  226         size = uap->len;
  227         prot = uap->prot & VM_PROT_ALL;
  228         flags = uap->flags;
  229         pos = uap->pos;
  230 
  231         fp = NULL;
  232         /* make sure mapping fits into numeric range etc */
  233         if ((uap->len == 0 && !SV_CURPROC_FLAG(SV_AOUT) &&
  234              curproc->p_osrel >= 800104) ||
  235             ((flags & MAP_ANON) && uap->fd != -1))
  236                 return (EINVAL);
  237 
  238         if (flags & MAP_STACK) {
  239                 if ((uap->fd != -1) ||
  240                     ((prot & (PROT_READ | PROT_WRITE)) != (PROT_READ | PROT_WRITE)))
  241                         return (EINVAL);
  242                 flags |= MAP_ANON;
  243                 pos = 0;
  244         }
  245 
  246         /*
  247          * Align the file position to a page boundary,
  248          * and save its page offset component.
  249          */
  250         pageoff = (pos & PAGE_MASK);
  251         pos -= pageoff;
  252 
  253         /* Adjust size for rounding (on both ends). */
  254         size += pageoff;                        /* low end... */
  255         size = (vm_size_t) round_page(size);    /* hi end */
  256 
  257         /*
  258          * Check for illegal addresses.  Watch out for address wrap... Note
  259          * that VM_*_ADDRESS are not constants due to casts (argh).
  260          */
  261         if (flags & MAP_FIXED) {
  262                 /*
  263                  * The specified address must have the same remainder
  264                  * as the file offset taken modulo PAGE_SIZE, so it
  265                  * should be aligned after adjustment by pageoff.
  266                  */
  267                 addr -= pageoff;
  268                 if (addr & PAGE_MASK)
  269                         return (EINVAL);
  270                 /* Address range must be all in user VM space. */
  271                 if (addr < vm_map_min(&vms->vm_map) ||
  272                     addr + size > vm_map_max(&vms->vm_map))
  273                         return (EINVAL);
  274                 if (addr + size < addr)
  275                         return (EINVAL);
  276         } else {
  277         /*
  278          * XXX for non-fixed mappings where no hint is provided or
  279          * the hint would fall in the potential heap space,
  280          * place it after the end of the largest possible heap.
  281          *
  282          * There should really be a pmap call to determine a reasonable
  283          * location.
  284          */
  285                 PROC_LOCK(td->td_proc);
  286                 if (addr == 0 ||
  287                     (addr >= round_page((vm_offset_t)vms->vm_taddr) &&
  288                     addr < round_page((vm_offset_t)vms->vm_daddr +
  289                     lim_max(td->td_proc, RLIMIT_DATA))))
  290                         addr = round_page((vm_offset_t)vms->vm_daddr +
  291                             lim_max(td->td_proc, RLIMIT_DATA));
  292                 PROC_UNLOCK(td->td_proc);
  293         }
  294         if (flags & MAP_ANON) {
  295                 /*
  296                  * Mapping blank space is trivial.
  297                  */
  298                 handle = NULL;
  299                 handle_type = OBJT_DEFAULT;
  300                 maxprot = VM_PROT_ALL;
  301                 pos = 0;
  302         } else {
  303                 /*
  304                  * Mapping file, get fp for validation and
  305                  * don't let the descriptor disappear on us if we block.
  306                  */
  307                 if ((error = fget(td, uap->fd, &fp)) != 0)
  308                         goto done;
  309                 if (fp->f_type == DTYPE_SHM) {
  310                         handle = fp->f_data;
  311                         handle_type = OBJT_SWAP;
  312                         maxprot = VM_PROT_NONE;
  313 
  314                         /* FREAD should always be set. */
  315                         if (fp->f_flag & FREAD)
  316                                 maxprot |= VM_PROT_EXECUTE | VM_PROT_READ;
  317                         if (fp->f_flag & FWRITE)
  318                                 maxprot |= VM_PROT_WRITE;
  319                         goto map;
  320                 }
  321                 if (fp->f_type != DTYPE_VNODE) {
  322                         error = ENODEV;
  323                         goto done;
  324                 }
  325 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
  326     defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
  327                 /*
  328                  * POSIX shared-memory objects are defined to have
  329                  * kernel persistence, and are not defined to support
  330                  * read(2)/write(2) -- or even open(2).  Thus, we can
  331                  * use MAP_ASYNC to trade on-disk coherence for speed.
  332                  * The shm_open(3) library routine turns on the FPOSIXSHM
  333                  * flag to request this behavior.
  334                  */
  335                 if (fp->f_flag & FPOSIXSHM)
  336                         flags |= MAP_NOSYNC;
  337 #endif
  338                 vp = fp->f_vnode;
  339                 /*
  340                  * Ensure that file and memory protections are
  341                  * compatible.  Note that we only worry about
  342                  * writability if mapping is shared; in this case,
  343                  * current and max prot are dictated by the open file.
  344                  * XXX use the vnode instead?  Problem is: what
  345                  * credentials do we use for determination? What if
  346                  * proc does a setuid?
  347                  */
  348                 if (vp->v_mount != NULL && vp->v_mount->mnt_flag & MNT_NOEXEC)
  349                         maxprot = VM_PROT_NONE;
  350                 else
  351                         maxprot = VM_PROT_EXECUTE;
  352                 if (fp->f_flag & FREAD) {
  353                         maxprot |= VM_PROT_READ;
  354                 } else if (prot & PROT_READ) {
  355                         error = EACCES;
  356                         goto done;
  357                 }
  358                 /*
  359                  * If we are sharing potential changes (either via
  360                  * MAP_SHARED or via the implicit sharing of character
  361                  * device mappings), and we are trying to get write
  362                  * permission although we opened it without asking
  363                  * for it, bail out.
  364                  */
  365                 if ((flags & MAP_SHARED) != 0) {
  366                         if ((fp->f_flag & FWRITE) != 0) {
  367                                 maxprot |= VM_PROT_WRITE;
  368                         } else if ((prot & PROT_WRITE) != 0) {
  369                                 error = EACCES;
  370                                 goto done;
  371                         }
  372                 } else if (vp->v_type != VCHR || (fp->f_flag & FWRITE) != 0) {
  373                         maxprot |= VM_PROT_WRITE;
  374                 }
  375                 handle = (void *)vp;
  376                 handle_type = OBJT_VNODE;
  377         }
  378 map:
  379 
  380         /*
  381          * Do not allow more then a certain number of vm_map_entry structures
  382          * per process.  Scale with the number of rforks sharing the map
  383          * to make the limit reasonable for threads.
  384          */
  385         if (max_proc_mmap &&
  386             vms->vm_map.nentries >= max_proc_mmap * vms->vm_refcnt) {
  387                 error = ENOMEM;
  388                 goto done;
  389         }
  390 
  391         td->td_fpop = fp;
  392         error = vm_mmap(&vms->vm_map, &addr, size, prot, maxprot,
  393             flags, handle_type, handle, pos);
  394         td->td_fpop = NULL;
  395 #ifdef HWPMC_HOOKS
  396         /* inform hwpmc(4) if an executable is being mapped */
  397         if (error == 0 && handle_type == OBJT_VNODE &&
  398             (prot & PROT_EXEC)) {
  399                 pkm.pm_file = handle;
  400                 pkm.pm_address = (uintptr_t) addr;
  401                 PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm);
  402         }
  403 #endif
  404         if (error == 0)
  405                 td->td_retval[0] = (register_t) (addr + pageoff);
  406 done:
  407         if (fp)
  408                 fdrop(fp, td);
  409 
  410         return (error);
  411 }
  412 
  413 int
  414 freebsd6_mmap(struct thread *td, struct freebsd6_mmap_args *uap)
  415 {
  416         struct mmap_args oargs;
  417 
  418         oargs.addr = uap->addr;
  419         oargs.len = uap->len;
  420         oargs.prot = uap->prot;
  421         oargs.flags = uap->flags;
  422         oargs.fd = uap->fd;
  423         oargs.pos = uap->pos;
  424         return (mmap(td, &oargs));
  425 }
  426 
  427 #ifdef COMPAT_43
  428 #ifndef _SYS_SYSPROTO_H_
  429 struct ommap_args {
  430         caddr_t addr;
  431         int len;
  432         int prot;
  433         int flags;
  434         int fd;
  435         long pos;
  436 };
  437 #endif
  438 int
  439 ommap(td, uap)
  440         struct thread *td;
  441         struct ommap_args *uap;
  442 {
  443         struct mmap_args nargs;
  444         static const char cvtbsdprot[8] = {
  445                 0,
  446                 PROT_EXEC,
  447                 PROT_WRITE,
  448                 PROT_EXEC | PROT_WRITE,
  449                 PROT_READ,
  450                 PROT_EXEC | PROT_READ,
  451                 PROT_WRITE | PROT_READ,
  452                 PROT_EXEC | PROT_WRITE | PROT_READ,
  453         };
  454 
  455 #define OMAP_ANON       0x0002
  456 #define OMAP_COPY       0x0020
  457 #define OMAP_SHARED     0x0010
  458 #define OMAP_FIXED      0x0100
  459 
  460         nargs.addr = uap->addr;
  461         nargs.len = uap->len;
  462         nargs.prot = cvtbsdprot[uap->prot & 0x7];
  463         nargs.flags = 0;
  464         if (uap->flags & OMAP_ANON)
  465                 nargs.flags |= MAP_ANON;
  466         if (uap->flags & OMAP_COPY)
  467                 nargs.flags |= MAP_COPY;
  468         if (uap->flags & OMAP_SHARED)
  469                 nargs.flags |= MAP_SHARED;
  470         else
  471                 nargs.flags |= MAP_PRIVATE;
  472         if (uap->flags & OMAP_FIXED)
  473                 nargs.flags |= MAP_FIXED;
  474         nargs.fd = uap->fd;
  475         nargs.pos = uap->pos;
  476         return (mmap(td, &nargs));
  477 }
  478 #endif                          /* COMPAT_43 */
  479 
  480 
  481 #ifndef _SYS_SYSPROTO_H_
  482 struct msync_args {
  483         void *addr;
  484         size_t len;
  485         int flags;
  486 };
  487 #endif
  488 /*
  489  * MPSAFE
  490  */
  491 int
  492 msync(td, uap)
  493         struct thread *td;
  494         struct msync_args *uap;
  495 {
  496         vm_offset_t addr;
  497         vm_size_t size, pageoff;
  498         int flags;
  499         vm_map_t map;
  500         int rv;
  501 
  502         addr = (vm_offset_t) uap->addr;
  503         size = uap->len;
  504         flags = uap->flags;
  505 
  506         pageoff = (addr & PAGE_MASK);
  507         addr -= pageoff;
  508         size += pageoff;
  509         size = (vm_size_t) round_page(size);
  510         if (addr + size < addr)
  511                 return (EINVAL);
  512 
  513         if ((flags & (MS_ASYNC|MS_INVALIDATE)) == (MS_ASYNC|MS_INVALIDATE))
  514                 return (EINVAL);
  515 
  516         map = &td->td_proc->p_vmspace->vm_map;
  517 
  518         /*
  519          * Clean the pages and interpret the return value.
  520          */
  521         rv = vm_map_sync(map, addr, addr + size, (flags & MS_ASYNC) == 0,
  522             (flags & MS_INVALIDATE) != 0);
  523         switch (rv) {
  524         case KERN_SUCCESS:
  525                 return (0);
  526         case KERN_INVALID_ADDRESS:
  527                 return (EINVAL);        /* Sun returns ENOMEM? */
  528         case KERN_INVALID_ARGUMENT:
  529                 return (EBUSY);
  530         default:
  531                 return (EINVAL);
  532         }
  533 }
  534 
  535 #ifndef _SYS_SYSPROTO_H_
  536 struct munmap_args {
  537         void *addr;
  538         size_t len;
  539 };
  540 #endif
  541 /*
  542  * MPSAFE
  543  */
  544 int
  545 munmap(td, uap)
  546         struct thread *td;
  547         struct munmap_args *uap;
  548 {
  549 #ifdef HWPMC_HOOKS
  550         struct pmckern_map_out pkm;
  551         vm_map_entry_t entry;
  552 #endif
  553         vm_offset_t addr;
  554         vm_size_t size, pageoff;
  555         vm_map_t map;
  556 
  557         addr = (vm_offset_t) uap->addr;
  558         size = uap->len;
  559         if (size == 0)
  560                 return (EINVAL);
  561 
  562         pageoff = (addr & PAGE_MASK);
  563         addr -= pageoff;
  564         size += pageoff;
  565         size = (vm_size_t) round_page(size);
  566         if (addr + size < addr)
  567                 return (EINVAL);
  568 
  569         /*
  570          * Check for illegal addresses.  Watch out for address wrap...
  571          */
  572         map = &td->td_proc->p_vmspace->vm_map;
  573         if (addr < vm_map_min(map) || addr + size > vm_map_max(map))
  574                 return (EINVAL);
  575         vm_map_lock(map);
  576 #ifdef HWPMC_HOOKS
  577         /*
  578          * Inform hwpmc if the address range being unmapped contains
  579          * an executable region.
  580          */
  581         if (vm_map_lookup_entry(map, addr, &entry)) {
  582                 for (;
  583                      entry != &map->header && entry->start < addr + size;
  584                      entry = entry->next) {
  585                         if (vm_map_check_protection(map, entry->start,
  586                                 entry->end, VM_PROT_EXECUTE) == TRUE) {
  587                                 pkm.pm_address = (uintptr_t) addr;
  588                                 pkm.pm_size = (size_t) size;
  589                                 PMC_CALL_HOOK(td, PMC_FN_MUNMAP,
  590                                     (void *) &pkm);
  591                                 break;
  592                         }
  593                 }
  594         }
  595 #endif
  596         /* returns nothing but KERN_SUCCESS anyway */
  597         vm_map_delete(map, addr, addr + size);
  598         vm_map_unlock(map);
  599         return (0);
  600 }
  601 
  602 #ifndef _SYS_SYSPROTO_H_
  603 struct mprotect_args {
  604         const void *addr;
  605         size_t len;
  606         int prot;
  607 };
  608 #endif
  609 /*
  610  * MPSAFE
  611  */
  612 int
  613 mprotect(td, uap)
  614         struct thread *td;
  615         struct mprotect_args *uap;
  616 {
  617         vm_offset_t addr;
  618         vm_size_t size, pageoff;
  619         vm_prot_t prot;
  620 
  621         addr = (vm_offset_t) uap->addr;
  622         size = uap->len;
  623         prot = uap->prot & VM_PROT_ALL;
  624 
  625         pageoff = (addr & PAGE_MASK);
  626         addr -= pageoff;
  627         size += pageoff;
  628         size = (vm_size_t) round_page(size);
  629         if (addr + size < addr)
  630                 return (EINVAL);
  631 
  632         switch (vm_map_protect(&td->td_proc->p_vmspace->vm_map, addr,
  633             addr + size, prot, FALSE)) {
  634         case KERN_SUCCESS:
  635                 return (0);
  636         case KERN_PROTECTION_FAILURE:
  637                 return (EACCES);
  638         case KERN_RESOURCE_SHORTAGE:
  639                 return (ENOMEM);
  640         }
  641         return (EINVAL);
  642 }
  643 
  644 #ifndef _SYS_SYSPROTO_H_
  645 struct minherit_args {
  646         void *addr;
  647         size_t len;
  648         int inherit;
  649 };
  650 #endif
  651 /*
  652  * MPSAFE
  653  */
  654 int
  655 minherit(td, uap)
  656         struct thread *td;
  657         struct minherit_args *uap;
  658 {
  659         vm_offset_t addr;
  660         vm_size_t size, pageoff;
  661         vm_inherit_t inherit;
  662 
  663         addr = (vm_offset_t)uap->addr;
  664         size = uap->len;
  665         inherit = uap->inherit;
  666 
  667         pageoff = (addr & PAGE_MASK);
  668         addr -= pageoff;
  669         size += pageoff;
  670         size = (vm_size_t) round_page(size);
  671         if (addr + size < addr)
  672                 return (EINVAL);
  673 
  674         switch (vm_map_inherit(&td->td_proc->p_vmspace->vm_map, addr,
  675             addr + size, inherit)) {
  676         case KERN_SUCCESS:
  677                 return (0);
  678         case KERN_PROTECTION_FAILURE:
  679                 return (EACCES);
  680         }
  681         return (EINVAL);
  682 }
  683 
  684 #ifndef _SYS_SYSPROTO_H_
  685 struct madvise_args {
  686         void *addr;
  687         size_t len;
  688         int behav;
  689 };
  690 #endif
  691 
  692 /*
  693  * MPSAFE
  694  */
  695 /* ARGSUSED */
  696 int
  697 madvise(td, uap)
  698         struct thread *td;
  699         struct madvise_args *uap;
  700 {
  701         vm_offset_t start, end;
  702         vm_map_t map;
  703         struct proc *p;
  704         int error;
  705 
  706         /*
  707          * Check for our special case, advising the swap pager we are
  708          * "immortal."
  709          */
  710         if (uap->behav == MADV_PROTECT) {
  711                 error = priv_check(td, PRIV_VM_MADV_PROTECT);
  712                 if (error == 0) {
  713                         p = td->td_proc;
  714                         PROC_LOCK(p);
  715                         p->p_flag |= P_PROTECTED;
  716                         PROC_UNLOCK(p);
  717                 }
  718                 return (error);
  719         }
  720         /*
  721          * Check for illegal behavior
  722          */
  723         if (uap->behav < 0 || uap->behav > MADV_CORE)
  724                 return (EINVAL);
  725         /*
  726          * Check for illegal addresses.  Watch out for address wrap... Note
  727          * that VM_*_ADDRESS are not constants due to casts (argh).
  728          */
  729         map = &td->td_proc->p_vmspace->vm_map;
  730         if ((vm_offset_t)uap->addr < vm_map_min(map) ||
  731             (vm_offset_t)uap->addr + uap->len > vm_map_max(map))
  732                 return (EINVAL);
  733         if (((vm_offset_t) uap->addr + uap->len) < (vm_offset_t) uap->addr)
  734                 return (EINVAL);
  735 
  736         /*
  737          * Since this routine is only advisory, we default to conservative
  738          * behavior.
  739          */
  740         start = trunc_page((vm_offset_t) uap->addr);
  741         end = round_page((vm_offset_t) uap->addr + uap->len);
  742 
  743         if (vm_map_madvise(map, start, end, uap->behav))
  744                 return (EINVAL);
  745         return (0);
  746 }
  747 
  748 #ifndef _SYS_SYSPROTO_H_
  749 struct mincore_args {
  750         const void *addr;
  751         size_t len;
  752         char *vec;
  753 };
  754 #endif
  755 
  756 /*
  757  * MPSAFE
  758  */
  759 /* ARGSUSED */
  760 int
  761 mincore(td, uap)
  762         struct thread *td;
  763         struct mincore_args *uap;
  764 {
  765         vm_offset_t addr, first_addr;
  766         vm_offset_t end, cend;
  767         pmap_t pmap;
  768         vm_map_t map;
  769         char *vec;
  770         int error = 0;
  771         int vecindex, lastvecindex;
  772         vm_map_entry_t current;
  773         vm_map_entry_t entry;
  774         int mincoreinfo;
  775         unsigned int timestamp;
  776 
  777         /*
  778          * Make sure that the addresses presented are valid for user
  779          * mode.
  780          */
  781         first_addr = addr = trunc_page((vm_offset_t) uap->addr);
  782         end = addr + (vm_size_t)round_page(uap->len);
  783         map = &td->td_proc->p_vmspace->vm_map;
  784         if (end > vm_map_max(map) || end < addr)
  785                 return (ENOMEM);
  786 
  787         /*
  788          * Address of byte vector
  789          */
  790         vec = uap->vec;
  791 
  792         pmap = vmspace_pmap(td->td_proc->p_vmspace);
  793 
  794         vm_map_lock_read(map);
  795 RestartScan:
  796         timestamp = map->timestamp;
  797 
  798         if (!vm_map_lookup_entry(map, addr, &entry)) {
  799                 vm_map_unlock_read(map);
  800                 return (ENOMEM);
  801         }
  802 
  803         /*
  804          * Do this on a map entry basis so that if the pages are not
  805          * in the current processes address space, we can easily look
  806          * up the pages elsewhere.
  807          */
  808         lastvecindex = -1;
  809         for (current = entry;
  810             (current != &map->header) && (current->start < end);
  811             current = current->next) {
  812 
  813                 /*
  814                  * check for contiguity
  815                  */
  816                 if (current->end < end &&
  817                     (entry->next == &map->header ||
  818                      current->next->start > current->end)) {
  819                         vm_map_unlock_read(map);
  820                         return (ENOMEM);
  821                 }
  822 
  823                 /*
  824                  * ignore submaps (for now) or null objects
  825                  */
  826                 if ((current->eflags & MAP_ENTRY_IS_SUB_MAP) ||
  827                         current->object.vm_object == NULL)
  828                         continue;
  829 
  830                 /*
  831                  * limit this scan to the current map entry and the
  832                  * limits for the mincore call
  833                  */
  834                 if (addr < current->start)
  835                         addr = current->start;
  836                 cend = current->end;
  837                 if (cend > end)
  838                         cend = end;
  839 
  840                 /*
  841                  * scan this entry one page at a time
  842                  */
  843                 while (addr < cend) {
  844                         /*
  845                          * Check pmap first, it is likely faster, also
  846                          * it can provide info as to whether we are the
  847                          * one referencing or modifying the page.
  848                          */
  849                         mincoreinfo = pmap_mincore(pmap, addr);
  850                         if (!mincoreinfo) {
  851                                 vm_pindex_t pindex;
  852                                 vm_ooffset_t offset;
  853                                 vm_page_t m;
  854                                 /*
  855                                  * calculate the page index into the object
  856                                  */
  857                                 offset = current->offset + (addr - current->start);
  858                                 pindex = OFF_TO_IDX(offset);
  859                                 VM_OBJECT_LOCK(current->object.vm_object);
  860                                 m = vm_page_lookup(current->object.vm_object,
  861                                         pindex);
  862                                 /*
  863                                  * if the page is resident, then gather information about
  864                                  * it.
  865                                  */
  866                                 if (m != NULL && m->valid != 0) {
  867                                         mincoreinfo = MINCORE_INCORE;
  868                                         vm_page_lock_queues();
  869                                         if (m->dirty ||
  870                                                 pmap_is_modified(m))
  871                                                 mincoreinfo |= MINCORE_MODIFIED_OTHER;
  872                                         if ((m->flags & PG_REFERENCED) ||
  873                                                 pmap_ts_referenced(m)) {
  874                                                 vm_page_flag_set(m, PG_REFERENCED);
  875                                                 mincoreinfo |= MINCORE_REFERENCED_OTHER;
  876                                         }
  877                                         vm_page_unlock_queues();
  878                                 }
  879                                 VM_OBJECT_UNLOCK(current->object.vm_object);
  880                         }
  881 
  882                         /*
  883                          * subyte may page fault.  In case it needs to modify
  884                          * the map, we release the lock.
  885                          */
  886                         vm_map_unlock_read(map);
  887 
  888                         /*
  889                          * calculate index into user supplied byte vector
  890                          */
  891                         vecindex = OFF_TO_IDX(addr - first_addr);
  892 
  893                         /*
  894                          * If we have skipped map entries, we need to make sure that
  895                          * the byte vector is zeroed for those skipped entries.
  896                          */
  897                         while ((lastvecindex + 1) < vecindex) {
  898                                 error = subyte(vec + lastvecindex, 0);
  899                                 if (error) {
  900                                         error = EFAULT;
  901                                         goto done2;
  902                                 }
  903                                 ++lastvecindex;
  904                         }
  905 
  906                         /*
  907                          * Pass the page information to the user
  908                          */
  909                         error = subyte(vec + vecindex, mincoreinfo);
  910                         if (error) {
  911                                 error = EFAULT;
  912                                 goto done2;
  913                         }
  914 
  915                         /*
  916                          * If the map has changed, due to the subyte, the previous
  917                          * output may be invalid.
  918                          */
  919                         vm_map_lock_read(map);
  920                         if (timestamp != map->timestamp)
  921                                 goto RestartScan;
  922 
  923                         lastvecindex = vecindex;
  924                         addr += PAGE_SIZE;
  925                 }
  926         }
  927 
  928         /*
  929          * subyte may page fault.  In case it needs to modify
  930          * the map, we release the lock.
  931          */
  932         vm_map_unlock_read(map);
  933 
  934         /*
  935          * Zero the last entries in the byte vector.
  936          */
  937         vecindex = OFF_TO_IDX(end - first_addr);
  938         while ((lastvecindex + 1) < vecindex) {
  939                 error = subyte(vec + lastvecindex, 0);
  940                 if (error) {
  941                         error = EFAULT;
  942                         goto done2;
  943                 }
  944                 ++lastvecindex;
  945         }
  946 
  947         /*
  948          * If the map has changed, due to the subyte, the previous
  949          * output may be invalid.
  950          */
  951         vm_map_lock_read(map);
  952         if (timestamp != map->timestamp)
  953                 goto RestartScan;
  954         vm_map_unlock_read(map);
  955 done2:
  956         return (error);
  957 }
  958 
  959 #ifndef _SYS_SYSPROTO_H_
  960 struct mlock_args {
  961         const void *addr;
  962         size_t len;
  963 };
  964 #endif
  965 /*
  966  * MPSAFE
  967  */
  968 int
  969 mlock(td, uap)
  970         struct thread *td;
  971         struct mlock_args *uap;
  972 {
  973         struct proc *proc;
  974         vm_offset_t addr, end, last, start;
  975         vm_size_t npages, size;
  976         int error;
  977 
  978         error = priv_check(td, PRIV_VM_MLOCK);
  979         if (error)
  980                 return (error);
  981         addr = (vm_offset_t)uap->addr;
  982         size = uap->len;
  983         last = addr + size;
  984         start = trunc_page(addr);
  985         end = round_page(last);
  986         if (last < addr || end < addr)
  987                 return (EINVAL);
  988         npages = atop(end - start);
  989         if (npages > vm_page_max_wired)
  990                 return (ENOMEM);
  991         proc = td->td_proc;
  992         PROC_LOCK(proc);
  993         if (ptoa(npages +
  994             pmap_wired_count(vm_map_pmap(&proc->p_vmspace->vm_map))) >
  995             lim_cur(proc, RLIMIT_MEMLOCK)) {
  996                 PROC_UNLOCK(proc);
  997                 return (ENOMEM);
  998         }
  999         PROC_UNLOCK(proc);
 1000         if (npages + cnt.v_wire_count > vm_page_max_wired)
 1001                 return (EAGAIN);
 1002         error = vm_map_wire(&proc->p_vmspace->vm_map, start, end,
 1003             VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
 1004         return (error == KERN_SUCCESS ? 0 : ENOMEM);
 1005 }
 1006 
 1007 #ifndef _SYS_SYSPROTO_H_
 1008 struct mlockall_args {
 1009         int     how;
 1010 };
 1011 #endif
 1012 
 1013 /*
 1014  * MPSAFE
 1015  */
 1016 int
 1017 mlockall(td, uap)
 1018         struct thread *td;
 1019         struct mlockall_args *uap;
 1020 {
 1021         vm_map_t map;
 1022         int error;
 1023 
 1024         map = &td->td_proc->p_vmspace->vm_map;
 1025         error = 0;
 1026 
 1027         if ((uap->how == 0) || ((uap->how & ~(MCL_CURRENT|MCL_FUTURE)) != 0))
 1028                 return (EINVAL);
 1029 
 1030 #if 0
 1031         /*
 1032          * If wiring all pages in the process would cause it to exceed
 1033          * a hard resource limit, return ENOMEM.
 1034          */
 1035         PROC_LOCK(td->td_proc);
 1036         if (map->size - ptoa(pmap_wired_count(vm_map_pmap(map)) >
 1037                 lim_cur(td->td_proc, RLIMIT_MEMLOCK))) {
 1038                 PROC_UNLOCK(td->td_proc);
 1039                 return (ENOMEM);
 1040         }
 1041         PROC_UNLOCK(td->td_proc);
 1042 #else
 1043         error = priv_check(td, PRIV_VM_MLOCK);
 1044         if (error)
 1045                 return (error);
 1046 #endif
 1047 
 1048         if (uap->how & MCL_FUTURE) {
 1049                 vm_map_lock(map);
 1050                 vm_map_modflags(map, MAP_WIREFUTURE, 0);
 1051                 vm_map_unlock(map);
 1052                 error = 0;
 1053         }
 1054 
 1055         if (uap->how & MCL_CURRENT) {
 1056                 /*
 1057                  * P1003.1-2001 mandates that all currently mapped pages
 1058                  * will be memory resident and locked (wired) upon return
 1059                  * from mlockall(). vm_map_wire() will wire pages, by
 1060                  * calling vm_fault_wire() for each page in the region.
 1061                  */
 1062                 error = vm_map_wire(map, vm_map_min(map), vm_map_max(map),
 1063                     VM_MAP_WIRE_USER|VM_MAP_WIRE_HOLESOK);
 1064                 error = (error == KERN_SUCCESS ? 0 : EAGAIN);
 1065         }
 1066 
 1067         return (error);
 1068 }
 1069 
 1070 #ifndef _SYS_SYSPROTO_H_
 1071 struct munlockall_args {
 1072         register_t dummy;
 1073 };
 1074 #endif
 1075 
 1076 /*
 1077  * MPSAFE
 1078  */
 1079 int
 1080 munlockall(td, uap)
 1081         struct thread *td;
 1082         struct munlockall_args *uap;
 1083 {
 1084         vm_map_t map;
 1085         int error;
 1086 
 1087         map = &td->td_proc->p_vmspace->vm_map;
 1088         error = priv_check(td, PRIV_VM_MUNLOCK);
 1089         if (error)
 1090                 return (error);
 1091 
 1092         /* Clear the MAP_WIREFUTURE flag from this vm_map. */
 1093         vm_map_lock(map);
 1094         vm_map_modflags(map, 0, MAP_WIREFUTURE);
 1095         vm_map_unlock(map);
 1096 
 1097         /* Forcibly unwire all pages. */
 1098         error = vm_map_unwire(map, vm_map_min(map), vm_map_max(map),
 1099             VM_MAP_WIRE_USER|VM_MAP_WIRE_HOLESOK);
 1100 
 1101         return (error);
 1102 }
 1103 
 1104 #ifndef _SYS_SYSPROTO_H_
 1105 struct munlock_args {
 1106         const void *addr;
 1107         size_t len;
 1108 };
 1109 #endif
 1110 /*
 1111  * MPSAFE
 1112  */
 1113 int
 1114 munlock(td, uap)
 1115         struct thread *td;
 1116         struct munlock_args *uap;
 1117 {
 1118         vm_offset_t addr, end, last, start;
 1119         vm_size_t size;
 1120         int error;
 1121 
 1122         error = priv_check(td, PRIV_VM_MUNLOCK);
 1123         if (error)
 1124                 return (error);
 1125         addr = (vm_offset_t)uap->addr;
 1126         size = uap->len;
 1127         last = addr + size;
 1128         start = trunc_page(addr);
 1129         end = round_page(last);
 1130         if (last < addr || end < addr)
 1131                 return (EINVAL);
 1132         error = vm_map_unwire(&td->td_proc->p_vmspace->vm_map, start, end,
 1133             VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
 1134         return (error == KERN_SUCCESS ? 0 : ENOMEM);
 1135 }
 1136 
 1137 /*
 1138  * vm_mmap_vnode()
 1139  *
 1140  * MPSAFE
 1141  *
 1142  * Helper function for vm_mmap.  Perform sanity check specific for mmap
 1143  * operations on vnodes.
 1144  */
 1145 int
 1146 vm_mmap_vnode(struct thread *td, vm_size_t objsize,
 1147     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
 1148     struct vnode *vp, vm_ooffset_t *foffp, vm_object_t *objp)
 1149 {
 1150         struct vattr va;
 1151         vm_object_t obj;
 1152         vm_offset_t foff;
 1153         struct mount *mp;
 1154         struct ucred *cred;
 1155         int error, flags;
 1156         int vfslocked;
 1157 
 1158         mp = vp->v_mount;
 1159         cred = td->td_ucred;
 1160         vfslocked = VFS_LOCK_GIANT(mp);
 1161         if ((error = vget(vp, LK_SHARED, td)) != 0) {
 1162                 VFS_UNLOCK_GIANT(vfslocked);
 1163                 return (error);
 1164         }
 1165         foff = *foffp;
 1166         flags = *flagsp;
 1167         obj = vp->v_object;
 1168         if (vp->v_type == VREG) {
 1169                 /*
 1170                  * Get the proper underlying object
 1171                  */
 1172                 if (obj == NULL) {
 1173                         error = EINVAL;
 1174                         goto done;
 1175                 }
 1176                 if (obj->handle != vp) {
 1177                         vput(vp);
 1178                         vp = (struct vnode*)obj->handle;
 1179                         vget(vp, LK_SHARED, td);
 1180                 }
 1181         } else if (vp->v_type == VCHR) {
 1182                 error = vm_mmap_cdev(td, objsize, prot, maxprotp, flagsp,
 1183                     vp->v_rdev, foffp, objp);
 1184                 if (error == 0)
 1185                         goto mark_atime;
 1186                 goto done;
 1187         } else {
 1188                 error = EINVAL;
 1189                 goto done;
 1190         }
 1191         if ((error = VOP_GETATTR(vp, &va, cred)))
 1192                 goto done;
 1193 #ifdef MAC
 1194         error = mac_vnode_check_mmap(cred, vp, prot, flags);
 1195         if (error != 0)
 1196                 goto done;
 1197 #endif
 1198         if ((flags & MAP_SHARED) != 0) {
 1199                 if ((va.va_flags & (SF_SNAPSHOT|IMMUTABLE|APPEND)) != 0) {
 1200                         if (prot & PROT_WRITE) {
 1201                                 error = EPERM;
 1202                                 goto done;
 1203                         }
 1204                         *maxprotp &= ~VM_PROT_WRITE;
 1205                 }
 1206         }
 1207         /*
 1208          * If it is a regular file without any references
 1209          * we do not need to sync it.
 1210          * Adjust object size to be the size of actual file.
 1211          */
 1212         objsize = round_page(va.va_size);
 1213         if (va.va_nlink == 0)
 1214                 flags |= MAP_NOSYNC;
 1215         obj = vm_pager_allocate(OBJT_VNODE, vp, objsize, prot, foff, td->td_ucred);
 1216         if (obj == NULL) {
 1217                 error = ENOMEM;
 1218                 goto done;
 1219         }
 1220         *objp = obj;
 1221         *flagsp = flags;
 1222 
 1223 mark_atime:
 1224         vfs_mark_atime(vp, cred);
 1225 
 1226 done:
 1227         vput(vp);
 1228         VFS_UNLOCK_GIANT(vfslocked);
 1229         return (error);
 1230 }
 1231 
 1232 /*
 1233  * vm_mmap_cdev()
 1234  *
 1235  * MPSAFE
 1236  *
 1237  * Helper function for vm_mmap.  Perform sanity check specific for mmap
 1238  * operations on cdevs.
 1239  */
 1240 int
 1241 vm_mmap_cdev(struct thread *td, vm_size_t objsize,
 1242     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
 1243     struct cdev *cdev, vm_ooffset_t *foff, vm_object_t *objp)
 1244 {
 1245         vm_object_t obj;
 1246         struct cdevsw *dsw;
 1247         int error, flags;
 1248 
 1249         flags = *flagsp;
 1250 
 1251         dsw = dev_refthread(cdev);
 1252         if (dsw == NULL)
 1253                 return (ENXIO);
 1254         if (dsw->d_flags & D_MMAP_ANON) {
 1255                 dev_relthread(cdev);
 1256                 *maxprotp = VM_PROT_ALL;
 1257                 *flagsp |= MAP_ANON;
 1258                 return (0);
 1259         }
 1260         /*
 1261          * cdevs do not provide private mappings of any kind.
 1262          */
 1263         if ((*maxprotp & VM_PROT_WRITE) == 0 &&
 1264             (prot & PROT_WRITE) != 0) {
 1265                 dev_relthread(cdev);
 1266                 return (EACCES);
 1267         }
 1268         if (flags & (MAP_PRIVATE|MAP_COPY)) {
 1269                 dev_relthread(cdev);
 1270                 return (EINVAL);
 1271         }
 1272         /*
 1273          * Force device mappings to be shared.
 1274          */
 1275         flags |= MAP_SHARED;
 1276 #ifdef MAC_XXX
 1277         error = mac_cdev_check_mmap(td->td_ucred, cdev, prot);
 1278         if (error != 0) {
 1279                 dev_relthread(cdev);
 1280                 return (error);
 1281         }
 1282 #endif
 1283         /*
 1284          * First, try d_mmap_single().  If that is not implemented
 1285          * (returns ENODEV), fall back to using the device pager.
 1286          * Note that d_mmap_single() must return a reference to the
 1287          * object (it needs to bump the reference count of the object
 1288          * it returns somehow).
 1289          *
 1290          * XXX assumes VM_PROT_* == PROT_*
 1291          */
 1292         error = dsw->d_mmap_single(cdev, foff, objsize, objp, (int)prot);
 1293         dev_relthread(cdev);
 1294         if (error != ENODEV)
 1295                 return (error);
 1296         obj = vm_pager_allocate(OBJT_DEVICE, cdev, objsize, prot, *foff,
 1297             td->td_ucred);
 1298         if (obj == NULL)
 1299                 return (EINVAL);
 1300         *objp = obj;
 1301         *flagsp = flags;
 1302         return (0);
 1303 }
 1304 
 1305 /*
 1306  * vm_mmap_shm()
 1307  *
 1308  * MPSAFE
 1309  *
 1310  * Helper function for vm_mmap.  Perform sanity check specific for mmap
 1311  * operations on shm file descriptors.
 1312  */
 1313 int
 1314 vm_mmap_shm(struct thread *td, vm_size_t objsize,
 1315     vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp,
 1316     struct shmfd *shmfd, vm_ooffset_t foff, vm_object_t *objp)
 1317 {
 1318         int error;
 1319 
 1320         if ((*maxprotp & VM_PROT_WRITE) == 0 &&
 1321             (prot & PROT_WRITE) != 0)
 1322                 return (EACCES);
 1323 #ifdef MAC
 1324         error = mac_posixshm_check_mmap(td->td_ucred, shmfd, prot, *flagsp);
 1325         if (error != 0)
 1326                 return (error);
 1327 #endif
 1328         error = shm_mmap(shmfd, objsize, foff, objp);
 1329         if (error)
 1330                 return (error);
 1331         return (0);
 1332 }
 1333 
 1334 /*
 1335  * vm_mmap()
 1336  *
 1337  * MPSAFE
 1338  *
 1339  * Internal version of mmap.  Currently used by mmap, exec, and sys5
 1340  * shared memory.  Handle is either a vnode pointer or NULL for MAP_ANON.
 1341  */
 1342 int
 1343 vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot,
 1344         vm_prot_t maxprot, int flags,
 1345         objtype_t handle_type, void *handle,
 1346         vm_ooffset_t foff)
 1347 {
 1348         boolean_t fitit;
 1349         vm_object_t object = NULL;
 1350         int rv = KERN_SUCCESS;
 1351         int docow, error;
 1352         struct thread *td = curthread;
 1353 
 1354         if (size == 0)
 1355                 return (0);
 1356 
 1357         size = round_page(size);
 1358 
 1359         PROC_LOCK(td->td_proc);
 1360         if (td->td_proc->p_vmspace->vm_map.size + size >
 1361             lim_cur(td->td_proc, RLIMIT_VMEM)) {
 1362                 PROC_UNLOCK(td->td_proc);
 1363                 return(ENOMEM);
 1364         }
 1365         PROC_UNLOCK(td->td_proc);
 1366 
 1367         /*
 1368          * We currently can only deal with page aligned file offsets.
 1369          * The check is here rather than in the syscall because the
 1370          * kernel calls this function internally for other mmaping
 1371          * operations (such as in exec) and non-aligned offsets will
 1372          * cause pmap inconsistencies...so we want to be sure to
 1373          * disallow this in all cases.
 1374          */
 1375         if (foff & PAGE_MASK)
 1376                 return (EINVAL);
 1377 
 1378         if ((flags & MAP_FIXED) == 0) {
 1379                 fitit = TRUE;
 1380                 *addr = round_page(*addr);
 1381         } else {
 1382                 if (*addr != trunc_page(*addr))
 1383                         return (EINVAL);
 1384                 fitit = FALSE;
 1385         }
 1386         /*
 1387          * Lookup/allocate object.
 1388          */
 1389         switch (handle_type) {
 1390         case OBJT_DEVICE:
 1391                 error = vm_mmap_cdev(td, size, prot, &maxprot, &flags,
 1392                     handle, &foff, &object);
 1393                 break;
 1394         case OBJT_VNODE:
 1395                 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags,
 1396                     handle, &foff, &object);
 1397                 break;
 1398         case OBJT_SWAP:
 1399                 error = vm_mmap_shm(td, size, prot, &maxprot, &flags,
 1400                     handle, foff, &object);
 1401                 break;
 1402         case OBJT_DEFAULT:
 1403                 if (handle == NULL) {
 1404                         error = 0;
 1405                         break;
 1406                 }
 1407                 /* FALLTHROUGH */
 1408         default:
 1409                 error = EINVAL;
 1410                 break;
 1411         }
 1412         if (error)
 1413                 return (error);
 1414         if (flags & MAP_ANON) {
 1415                 object = NULL;
 1416                 docow = 0;
 1417                 /*
 1418                  * Unnamed anonymous regions always start at 0.
 1419                  */
 1420                 if (handle == 0)
 1421                         foff = 0;
 1422         } else {
 1423                 docow = MAP_PREFAULT_PARTIAL;
 1424         }
 1425 
 1426         if ((flags & (MAP_ANON|MAP_SHARED)) == 0)
 1427                 docow |= MAP_COPY_ON_WRITE;
 1428         if (flags & MAP_NOSYNC)
 1429                 docow |= MAP_DISABLE_SYNCER;
 1430         if (flags & MAP_NOCORE)
 1431                 docow |= MAP_DISABLE_COREDUMP;
 1432 
 1433         if (flags & MAP_STACK)
 1434                 rv = vm_map_stack(map, *addr, size, prot, maxprot,
 1435                     docow | MAP_STACK_GROWS_DOWN);
 1436         else if (fitit)
 1437                 rv = vm_map_find(map, object, foff, addr, size,
 1438                     object != NULL && object->type == OBJT_DEVICE ?
 1439                     VMFS_ALIGNED_SPACE : VMFS_ANY_SPACE, prot, maxprot, docow);
 1440         else
 1441                 rv = vm_map_fixed(map, object, foff, *addr, size,
 1442                                  prot, maxprot, docow);
 1443 
 1444         if (rv != KERN_SUCCESS) {
 1445                 /*
 1446                  * Lose the object reference. Will destroy the
 1447                  * object if it's an unnamed anonymous mapping
 1448                  * or named anonymous without other references.
 1449                  */
 1450                 vm_object_deallocate(object);
 1451         } else if (flags & MAP_SHARED) {
 1452                 /*
 1453                  * Shared memory is also shared with children.
 1454                  */
 1455                 rv = vm_map_inherit(map, *addr, *addr + size, VM_INHERIT_SHARE);
 1456                 if (rv != KERN_SUCCESS)
 1457                         (void) vm_map_remove(map, *addr, *addr + size);
 1458         }
 1459 
 1460         /*
 1461          * If the process has requested that all future mappings
 1462          * be wired, then heed this.
 1463          */
 1464         if ((rv == KERN_SUCCESS) && (map->flags & MAP_WIREFUTURE))
 1465                 vm_map_wire(map, *addr, *addr + size,
 1466                     VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES);
 1467 
 1468         switch (rv) {
 1469         case KERN_SUCCESS:
 1470                 return (0);
 1471         case KERN_INVALID_ADDRESS:
 1472         case KERN_NO_SPACE:
 1473                 return (ENOMEM);
 1474         case KERN_PROTECTION_FAILURE:
 1475                 return (EACCES);
 1476         default:
 1477                 return (EINVAL);
 1478         }
 1479 }

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