1  /* msync -- Synchronize mapped memory to external storage.  Mach version.
       2     Copyright (C) 2002-2023 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    while (cur < target)
      51      {
      52        vm_address_t begin = cur;
      53  
      54        err = __vm_region (__mach_task_self (),
      55  			 &begin, &len, &prot, &max_prot, &inherit,
      56  			 &shared, &obj, &offset);
      57  
      58        if (err != KERN_SUCCESS)
      59  	return __hurd_fail (err);
      60  
      61        if (begin > cur)
      62  	/* We were given an address before the first region,
      63  	   or we found a hole.  */
      64  	cur = begin;
      65  
      66        if (cur >= target)
      67  	/* We were given an ending address within a hole. */
      68  	break;
      69  
      70        if (MACH_PORT_VALID (obj))
      71  	{
      72  	  vm_size_t sync_len;
      73  
      74  	  if (begin + len > target)
      75  	    sync_len = target - begin;
      76  	  else
      77  	    sync_len = len;
      78  
      79  	  cancel_oldtype = LIBC_CANCEL_ASYNC();
      80  	  err = __vm_object_sync (obj, cur - begin + offset, sync_len,
      81  				  should_flush, 1, should_iosync);
      82  	  LIBC_CANCEL_RESET (cancel_oldtype);
      83  	  __mach_port_deallocate (__mach_task_self (), obj);
      84  
      85  	  if (err)
      86  	    return __hurd_fail (err);
      87  
      88  	}
      89  
      90        cur = begin + len;
      91      }
      92  
      93    return 0;
      94  }