sys/vm/vm_unix.c

   1 /*
   2  * (MPSAFE)
   3  *
   4  * Copyright (c) 1988 University of Utah.
   5  * Copyright (c) 1991, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * the Systems Programming Group of the University of Utah Computer
  10  * Science Department.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  *
  40  * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
  41  *
  42  *      @(#)vm_unix.c   8.1 (Berkeley) 6/11/93
  43  * $FreeBSD: src/sys/vm/vm_unix.c,v 1.24.2.2 2002/07/02 20:06:19 dillon Exp $
  44  * $DragonFly: src/sys/vm/vm_unix.c,v 1.7 2006/11/07 17:51:24 dillon Exp $
  45  */
  46
  47 /*
  48  * Traditional sbrk/grow interface to VM
  49  */
  50 #include <sys/param.h>
  51 #include <sys/sysproto.h>
  52 #include <sys/proc.h>
  53 #include <sys/resourcevar.h>
  54
  55 #include <vm/vm.h>
  56 #include <vm/vm_param.h>
  57 #include <sys/lock.h>
  58 #include <vm/pmap.h>
  59 #include <vm/vm_map.h>
  60
  61 #include <sys/thread.h>
  62
  63 /*
  64  * sys_obreak backs the C library sbrk call
  65  *
  66  * obreak_args(char *nsize)
  67  *
  68  * No requirements.
  69  */
  70 int
  71 sys_obreak(struct obreak_args *uap)
  72 {
  73         struct proc *p = curproc;
  74         struct vmspace *vm = p->p_vmspace;
  75         vm_offset_t new, old, base;
  76         int rv;
  77         int error;
  78
  79         error = 0;
  80         lwkt_gettoken(&vm_token);
  81
  82         base = round_page((vm_offset_t) vm->vm_daddr);
  83         new = round_page((vm_offset_t)uap->nsize);
  84         old = base + ctob(vm->vm_dsize);
  85
  86         if (new > base) {
  87                 /*
  88                  * We check resource limits here, but alow processes to
  89                  * reduce their usage, even if they remain over the limit.
  90                  */
  91                 if (new > old &&
  92                     (new - base) > (vm_offset_t) p->p_rlimit[RLIMIT_DATA].rlim_cur) {
  93                         error = ENOMEM;
  94                         goto done;
  95                 }
  96                 if (new >= VM_MAX_USER_ADDRESS) {
  97                         error = ENOMEM;
  98                         goto done;
  99                 }
 100         } else if (new < base) {
 101                 /*
 102                  * This is simply an invalid value.  If someone wants to
 103                  * do fancy address space manipulations, mmap and munmap
 104                  * can do most of what the user would want.
 105                  */
 106                 error = EINVAL;
 107                 goto done;
 108         }
 109
 110         if (new > old) {
 111                 vm_size_t diff;
 112
 113                 diff = new - old;
 114                 if (vm->vm_map.size + diff > p->p_rlimit[RLIMIT_VMEM].rlim_cur) {
 115                         error = ENOMEM;
 116                         goto done;
 117                 }
 118                 rv = vm_map_find(&vm->vm_map, NULL, 0, &old,
 119                                  diff, PAGE_SIZE,
 120                                  FALSE, VM_MAPTYPE_NORMAL,
 121                                  VM_PROT_ALL, VM_PROT_ALL,
 122                                  0);
 123                 if (rv != KERN_SUCCESS) {
 124                         error = ENOMEM;
 125                         goto done;
 126                 }
 127                 vm->vm_dsize += btoc(diff);
 128         } else if (new < old) {
 129                 rv = vm_map_remove(&vm->vm_map, new, old);
 130                 if (rv != KERN_SUCCESS) {
 131                         error = ENOMEM;
 132                         goto done;
 133                 }
 134                 vm->vm_dsize -= btoc(old - new);
 135         }
 136 done:
 137         lwkt_reltoken(&vm_token);
 138         return (error);
 139 }