FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_unix.c

     /*-
      * Copyright (c) 1988 University of Utah.
      * Copyright (c) 1991, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * the Systems Programming Group of the University of Utah Computer
      * Science Department.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
     *
     *      @(#)vm_unix.c   8.1 (Berkeley) 6/11/93
     */
    
    /*
     * Traditional sbrk/grow interface to VM
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/8.0/sys/vm/vm_unix.c 190949 2009-04-11 22:34:08Z alc $");
    
    #include <sys/param.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/proc.h>
    #include <sys/resourcevar.h>
    #include <sys/sysproto.h>
    #include <sys/systm.h>
    
    #include <vm/vm.h>
    #include <vm/vm_param.h>
    #include <vm/pmap.h>
    #include <vm/vm_map.h>
    
    #ifndef _SYS_SYSPROTO_H_
    struct obreak_args {
            char *nsize;
    };
    #endif
    
    /*
     * MPSAFE
     */
    /* ARGSUSED */
    int
    obreak(td, uap)
            struct thread *td;
            struct obreak_args *uap;
    {
            struct vmspace *vm = td->td_proc->p_vmspace;
            vm_offset_t new, old, base;
            rlim_t datalim, vmemlim;
            int rv;
            int error = 0;
            boolean_t do_map_wirefuture;
    
            PROC_LOCK(td->td_proc);
            datalim = lim_cur(td->td_proc, RLIMIT_DATA);
            vmemlim = lim_cur(td->td_proc, RLIMIT_VMEM);
            PROC_UNLOCK(td->td_proc);
    
            do_map_wirefuture = FALSE;
            new = round_page((vm_offset_t)uap->nsize);
            vm_map_lock(&vm->vm_map);
    
            base = round_page((vm_offset_t) vm->vm_daddr);
            old = base + ctob(vm->vm_dsize);
            if (new > base) {
                    /*
                     * Check the resource limit, but allow a process to reduce
                     * its usage, even if it remains over the limit.
                     */
                    if (new - base > datalim && new > old) {
                            error = ENOMEM;
                            goto done;
                   }
                   if (new > vm_map_max(&vm->vm_map)) {
                           error = ENOMEM;
                           goto done;
                   }
           } else if (new < base) {
                   /*
                    * This is simply an invalid value.  If someone wants to
                    * do fancy address space manipulations, mmap and munmap
                    * can do most of what the user would want.
                    */
                   error = EINVAL;
                   goto done;
           }
           if (new > old) {
                   if (vm->vm_map.size + (new - old) > vmemlim) {
                           error = ENOMEM;
                           goto done;
                   }
                   rv = vm_map_insert(&vm->vm_map, NULL, 0, old, new,
                       VM_PROT_RW, VM_PROT_ALL, 0);
                   if (rv != KERN_SUCCESS) {
                           error = ENOMEM;
                           goto done;
                   }
                   vm->vm_dsize += btoc(new - old);
                   /*
                    * Handle the MAP_WIREFUTURE case for legacy applications,
                    * by marking the newly mapped range of pages as wired.
                    * We are not required to perform a corresponding
                    * vm_map_unwire() before vm_map_delete() below, as
                    * it will forcibly unwire the pages in the range.
                    *
                    * XXX If the pages cannot be wired, no error is returned.
                    */
                   if ((vm->vm_map.flags & MAP_WIREFUTURE) == MAP_WIREFUTURE) {
                           if (bootverbose)
                                   printf("obreak: MAP_WIREFUTURE set\n");
                           do_map_wirefuture = TRUE;
                   }
           } else if (new < old) {
                   rv = vm_map_delete(&vm->vm_map, new, old);
                   if (rv != KERN_SUCCESS) {
                           error = ENOMEM;
                           goto done;
                   }
                   vm->vm_dsize -= btoc(old - new);
           }
   done:
           vm_map_unlock(&vm->vm_map);
   
           if (do_map_wirefuture)
                   (void) vm_map_wire(&vm->vm_map, old, new,
                       VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES);
   
           return (error);
   }
   
   #ifndef _SYS_SYSPROTO_H_
   struct ovadvise_args {
           int anom;
   };
   #endif
   
   /*
    * MPSAFE
    */
   /* ARGSUSED */
   int
   ovadvise(td, uap)
           struct thread *td;
           struct ovadvise_args *uap;
   {
           /* START_GIANT_OPTIONAL */
           /* END_GIANT_OPTIONAL */
           return (EINVAL);
   }

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