sysdeps/mach/hurd/msync.c

   1 /* msync -- Synchronize mapped memory to external storage.  Mach version.
   2    Copyright (C) 2002-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sys/types.h>
  20 #include <sys/mman.h>
  21 #include <errno.h>
  22
  23 #include <hurd/hurd.h>
  24
  25 /* Synchronize the region starting at ADDR and extending LEN bytes with the
  26    file it maps.  Filesystem operations on a file being mapped are
  27    unpredictable before this is done.  */
  28
  29 int
  30 msync (void *addr, size_t length, int flags)
  31 {
  32   boolean_t should_flush = flags & MS_INVALIDATE ? 1 : 0;
  33   boolean_t should_iosync = flags & MS_ASYNC ? 0 : 1;
  34
  35   vm_address_t cur = (vm_address_t) addr;
  36   vm_address_t target = cur + length;
  37
  38   vm_size_t len;
  39   vm_prot_t prot;
  40   vm_prot_t max_prot;
  41   vm_inherit_t inherit;
  42   boolean_t shared;
  43   memory_object_name_t obj;
  44   vm_offset_t offset;
  45
  46   kern_return_t err;
  47
  48   if (flags & (MS_SYNC | MS_ASYNC) == (MS_SYNC | MS_ASYNC))
  49     return __hurd_fail (EINVAL);
  50
  51   while (cur < target)
  52     {
  53       vm_address_t begin = cur;
  54
  55       err = __vm_region (__mach_task_self (),
  56                          &begin, &len, &prot, &max_prot, &inherit,
  57                          &shared, &obj, &offset);
  58
  59       if (err != KERN_SUCCESS)
  60         return __hurd_fail (err);
  61
  62       if (begin > cur)
  63         /* We were given an address before the first region,
  64            or we found a hole.  */
  65         cur = begin;
  66
  67       if (cur >= target)
  68         /* We were given an ending address within a hole. */
  69         break;
  70
  71       if (MACH_PORT_VALID (obj))
  72         {
  73           vm_size_t sync_len;
  74
  75           if (begin + len > target)
  76             sync_len = target - begin;
  77           else
  78             sync_len = len;
  79
  80           err = __vm_object_sync (obj, cur - begin + offset, sync_len,
  81                                   should_flush, 1, should_iosync);
  82           __mach_port_deallocate (__mach_task_self (), obj);
  83
  84           if (err)
  85             return __hurd_fail (err);
  86
  87         }
  88
  89       cur = begin + len;
  90     }
  91
  92   return 0;
  93 }