sysdeps/mach/hurd/msync.c

   1 /* msync -- Synchronize mapped memory to external storage.  Mach version.
   2    Copyright (C) 2002-2021 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <sys/types.h>
  20 #include <sys/mman.h>
  21 #include <errno.h>
  22 #include <sysdep-cancel.h>
  23
  24 #include <hurd/hurd.h>
  25
  26 /* Synchronize the region starting at ADDR and extending LEN bytes with the
  27    file it maps.  Filesystem operations on a file being mapped are
  28    unpredictable before this is done.  */
  29
  30 int
  31 msync (void *addr, size_t length, int flags)
  32 {
  33   boolean_t should_flush = flags & MS_INVALIDATE ? 1 : 0;
  34   boolean_t should_iosync = flags & MS_ASYNC ? 0 : 1;
  35
  36   vm_address_t cur = (vm_address_t) addr;
  37   vm_address_t target = cur + length;
  38
  39   vm_size_t len;
  40   vm_prot_t prot;
  41   vm_prot_t max_prot;
  42   vm_inherit_t inherit;
  43   boolean_t shared;
  44   memory_object_name_t obj;
  45   vm_offset_t offset;
  46
  47   kern_return_t err;
  48   int cancel_oldtype;
  49
  50   if (flags & (MS_SYNC | MS_ASYNC) == (MS_SYNC | MS_ASYNC))
  51     return __hurd_fail (EINVAL);
  52
  53   while (cur < target)
  54     {
  55       vm_address_t begin = cur;
  56
  57       err = __vm_region (__mach_task_self (),
  58                          &begin, &len, &prot, &max_prot, &inherit,
  59                          &shared, &obj, &offset);
  60
  61       if (err != KERN_SUCCESS)
  62         return __hurd_fail (err);
  63
  64       if (begin > cur)
  65         /* We were given an address before the first region,
  66            or we found a hole.  */
  67         cur = begin;
  68
  69       if (cur >= target)
  70         /* We were given an ending address within a hole. */
  71         break;
  72
  73       if (MACH_PORT_VALID (obj))
  74         {
  75           vm_size_t sync_len;
  76
  77           if (begin + len > target)
  78             sync_len = target - begin;
  79           else
  80             sync_len = len;
  81
  82           cancel_oldtype = LIBC_CANCEL_ASYNC();
  83           err = __vm_object_sync (obj, cur - begin + offset, sync_len,
  84                                   should_flush, 1, should_iosync);
  85           LIBC_CANCEL_RESET (cancel_oldtype);
  86           __mach_port_deallocate (__mach_task_self (), obj);
  87
  88           if (err)
  89             return __hurd_fail (err);
  90
  91         }
  92
  93       cur = begin + len;
  94     }
  95
  96   return 0;
  97 }