sys/vm/vm_unix.c

   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  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
  39  *
  40  *      @(#)vm_unix.c   8.1 (Berkeley) 6/11/93
  41  * $FreeBSD: src/sys/vm/vm_unix.c,v 1.24.2.2 2002/07/02 20:06:19 dillon Exp $
  42  * $DragonFly: src/sys/vm/vm_unix.c,v 1.7 2006/11/07 17:51:24 dillon Exp $
  43  */
  44
  45 /*
  46  * Traditional sbrk/grow interface to VM
  47  */
  48 #include <sys/param.h>
  49 #include <sys/sysproto.h>
  50 #include <sys/proc.h>
  51 #include <sys/resourcevar.h>
  52
  53 #include <vm/vm.h>
  54 #include <vm/vm_param.h>
  55 #include <sys/lock.h>
  56 #include <vm/pmap.h>
  57 #include <vm/vm_map.h>
  58
  59 #include <sys/mplock2.h>
  60
  61 /*
  62  * obreak_args(char *nsize)
  63  *
  64  * MPALMOSTSAFE
  65  */
  66 int
  67 sys_obreak(struct obreak_args *uap)
  68 {
  69         struct proc *p = curproc;
  70         struct vmspace *vm = p->p_vmspace;
  71         vm_offset_t new, old, base;
  72         int rv;
  73         int error;
  74
  75         error = 0;
  76         get_mplock();
  77
  78         base = round_page((vm_offset_t) vm->vm_daddr);
  79         new = round_page((vm_offset_t)uap->nsize);
  80         old = base + ctob(vm->vm_dsize);
  81
  82         if (new > base) {
  83                 /*
  84                  * We check resource limits here, but alow processes to
  85                  * reduce their usage, even if they remain over the limit.
  86                  */
  87                 if (new > old &&
  88                     (new - base) > (vm_offset_t) p->p_rlimit[RLIMIT_DATA].rlim_cur) {
  89                         error = ENOMEM;
  90                         goto done;
  91                 }
  92                 if (new >= VM_MAX_USER_ADDRESS) {
  93                         error = ENOMEM;
  94                         goto done;
  95                 }
  96         } else if (new < base) {
  97                 /*
  98                  * This is simply an invalid value.  If someone wants to
  99                  * do fancy address space manipulations, mmap and munmap
 100                  * can do most of what the user would want.
 101                  */
 102                 error = EINVAL;
 103                 goto done;
 104         }
 105
 106         if (new > old) {
 107                 vm_size_t diff;
 108
 109                 diff = new - old;
 110                 if (vm->vm_map.size + diff > p->p_rlimit[RLIMIT_VMEM].rlim_cur) {
 111                         error = ENOMEM;
 112                         goto done;
 113                 }
 114                 rv = vm_map_find(&vm->vm_map, NULL, 0,
 115                                  &old, diff,
 116                                  FALSE,
 117                                  VM_MAPTYPE_NORMAL,
 118                                  VM_PROT_ALL, VM_PROT_ALL,
 119                                  0);
 120                 if (rv != KERN_SUCCESS) {
 121                         error = ENOMEM;
 122                         goto done;
 123                 }
 124                 vm->vm_dsize += btoc(diff);
 125         } else if (new < old) {
 126                 rv = vm_map_remove(&vm->vm_map, new, old);
 127                 if (rv != KERN_SUCCESS) {
 128                         error = ENOMEM;
 129                         goto done;
 130                 }
 131                 vm->vm_dsize -= btoc(old - new);
 132         }
 133 done:
 134         rel_mplock();
 135         return (error);
 136 }