Ejemplo n.º 1
0
__ptr_t
__mmap (__ptr_t addr, size_t len, int prot, int flags, int fd, off_t offset)
{
  error_t err;
  vm_prot_t vmprot;
  memory_object_t memobj;
  vm_address_t mapaddr;

  mapaddr = (vm_address_t) addr;

  /* ADDR and OFFSET must be page-aligned.  */
  if ((mapaddr & (__vm_page_size - 1)) || (offset & (__vm_page_size - 1)))
    return (__ptr_t) (long int) __hurd_fail (EINVAL);

  if ((flags & (MAP_TYPE|MAP_INHERIT)) == MAP_ANON
      && prot == (PROT_READ|PROT_WRITE)) /* cf VM_PROT_DEFAULT */
    {
      /* vm_allocate has (a little) less overhead in the kernel too.  */
      err = __vm_allocate (__mach_task_self (), &mapaddr, len, mapaddr == 0);

      if (err == KERN_NO_SPACE)
	{
	  if (flags & MAP_FIXED)
	    {
	      /* XXX this is not atomic as it is in unix! */
	      /* The region is already allocated; deallocate it first.  */
	      err = __vm_deallocate (__mach_task_self (), mapaddr, len);
	      if (!err)
		err = __vm_allocate (__mach_task_self (), &mapaddr, len, 0);
	    }
	  else if (mapaddr != 0)
	    err = __vm_allocate (__mach_task_self (), &mapaddr, len, 1);
	}

      return err ? (__ptr_t) (long int) __hurd_fail (err) : (__ptr_t) mapaddr;
    }

  vmprot = VM_PROT_NONE;
  if (prot & PROT_READ)
    vmprot |= VM_PROT_READ;
  if (prot & PROT_WRITE)
    vmprot |= VM_PROT_WRITE;
  if (prot & PROT_EXEC)
    vmprot |= VM_PROT_EXECUTE;

  switch (flags & MAP_TYPE)
    {
    default:
      return (__ptr_t) (long int) __hurd_fail (EINVAL);

    case MAP_ANON:
      memobj = MACH_PORT_NULL;
      break;

    case MAP_FILE:
    case 0:			/* Allow, e.g., just MAP_SHARED.  */
      {
	mach_port_t robj, wobj;
	if (err = HURD_DPORT_USE (fd, __io_map (port, &robj, &wobj)))
	  {
	    if (err == MIG_BAD_ID || err == EOPNOTSUPP || err == ENOSYS)
	      err = ENODEV;	/* File descriptor doesn't support mmap.  */
	    return (__ptr_t) (long int) __hurd_dfail (fd, err);
	  }
	switch (prot & (PROT_READ|PROT_WRITE))
	  {
	  /* Although it apparently doesn't make sense to map a file with
	     protection set to PROT_NONE, it is actually sometimes done.
	     In particular, that's how localedef reserves some space for
	     the locale archive file, the rationale being that some
	     implementations take into account whether the mapping is
	     anonymous or not when selecting addresses.  */
	  case PROT_NONE:
	  case PROT_READ:
	    memobj = robj;
	    if (wobj != MACH_PORT_NULL)
	      __mach_port_deallocate (__mach_task_self (), wobj);
	    break;
	  case PROT_WRITE:
	    memobj = wobj;
	    if (robj != MACH_PORT_NULL)
	      __mach_port_deallocate (__mach_task_self (), robj);
	    break;
	  case PROT_READ|PROT_WRITE:
	    if (robj == wobj)
	      {
		memobj = wobj;
		/* Remove extra reference.  */
		__mach_port_deallocate (__mach_task_self (), memobj);
	      }
	    else if (wobj == MACH_PORT_NULL && /* Not writable by mapping.  */
		     !(flags & MAP_SHARED))
	      /* The file can only be mapped for reading.  Since we are
		 making a private mapping, we will never try to write the
		 object anyway, so we don't care.  */
	      memobj = robj;
	    else
	      {
		__mach_port_deallocate (__mach_task_self (), wobj);
		return (__ptr_t) (long int) __hurd_fail (EACCES);
	      }
	    break;
	  default:
	    __builtin_unreachable ();
	  }
	break;
	/* XXX handle MAP_NOEXTEND */
      }
    }

  /* XXX handle MAP_INHERIT */

  err = __vm_map (__mach_task_self (),
		  &mapaddr, (vm_size_t) len, (vm_address_t) 0,
		  mapaddr == 0,
		  memobj, (vm_offset_t) offset,
		  ! (flags & MAP_SHARED),
		  vmprot, VM_PROT_ALL,
		  (flags & MAP_SHARED) ? VM_INHERIT_SHARE : VM_INHERIT_COPY);

  if (err == KERN_NO_SPACE)
    {
      if (flags & MAP_FIXED)
	{
	  /* XXX this is not atomic as it is in unix! */
	  /* The region is already allocated; deallocate it first.  */
	  err = __vm_deallocate (__mach_task_self (), mapaddr, len);
	  if (! err)
	    err = __vm_map (__mach_task_self (),
			    &mapaddr, (vm_size_t) len, (vm_address_t) 0,
			    0, memobj, (vm_offset_t) offset,
			    ! (flags & MAP_SHARED),
			    vmprot, VM_PROT_ALL,
			    (flags & MAP_SHARED) ? VM_INHERIT_SHARE
			    : VM_INHERIT_COPY);
	}
      else if (mapaddr != 0)
	err = __vm_map (__mach_task_self (),
			&mapaddr, (vm_size_t) len, (vm_address_t) 0,
			1, memobj, (vm_offset_t) offset,
			! (flags & MAP_SHARED),
			vmprot, VM_PROT_ALL,
			(flags & MAP_SHARED) ? VM_INHERIT_SHARE
			: VM_INHERIT_COPY);
    }

  if (memobj != MACH_PORT_NULL)
    __mach_port_deallocate (__mach_task_self (), memobj);

  if (err)
    return (__ptr_t) (long int) __hurd_fail (err);

  return (__ptr_t) mapaddr;
}
Ejemplo n.º 2
0
__ptr_t
__mmap (__ptr_t addr, size_t len, int prot, int flags, int fd, off_t offset)
{
  error_t err;
  vm_prot_t vmprot;
  memory_object_t memobj;
  vm_address_t mapaddr;
  vm_size_t pageoff;

  mapaddr = (vm_address_t) addr;

  if ((flags & (MAP_TYPE|MAP_INHERIT)) == MAP_ANON
      && prot == (PROT_READ|PROT_WRITE)) /* cf VM_PROT_DEFAULT */
    {
      /* vm_allocate has (a little) less overhead in the kernel too.  */
      err = __vm_allocate (__mach_task_self (), &mapaddr, len,
			   !(flags & MAP_FIXED));

      if (err == KERN_NO_SPACE && (flags & MAP_FIXED))
	{
	  /* XXX this is not atomic as it is in unix! */
	  /* The region is already allocated; deallocate it first.  */
	  err = __vm_deallocate (__mach_task_self (), mapaddr, len);
	  if (!err)
	    err = __vm_allocate (__mach_task_self (), &mapaddr, len, 0);
	}

      return err ? (__ptr_t) (long int) __hurd_fail (err) : (__ptr_t) mapaddr;
    }

  pageoff = offset & (vm_page_size - 1);
  offset &= ~(vm_page_size - 1);

  if (flags & MAP_FIXED)
    {
      /* A specific address is requested.  It need not be page-aligned;
	 it just needs to be congruent with the object offset.  */
      if ((mapaddr & (vm_page_size - 1)) != pageoff)
	return (__ptr_t) (long int) __hurd_fail (EINVAL);
      else
	/* We will add back PAGEOFF after mapping.  */
	mapaddr -= pageoff;
    }

  vmprot = VM_PROT_NONE;
  if (prot & PROT_READ)
    vmprot |= VM_PROT_READ;
  if (prot & PROT_WRITE)
    vmprot |= VM_PROT_WRITE;
  if (prot & PROT_EXEC)
    vmprot |= VM_PROT_EXECUTE;

  switch (flags & MAP_TYPE)
    {
    default:
      return (__ptr_t) (long int) __hurd_fail (EINVAL);

    case MAP_ANON:
      memobj = MACH_PORT_NULL;
      break;

    case MAP_FILE:
    case 0:			/* Allow, e.g., just MAP_SHARED.  */
      {
	mach_port_t robj, wobj;
	if (err = HURD_DPORT_USE (fd, __io_map (port, &robj, &wobj)))
	  return (__ptr_t) (long int) __hurd_dfail (fd, err);
	switch (prot & (PROT_READ|PROT_WRITE))
	  {
	  case PROT_READ:
	    memobj = robj;
	    if (wobj != MACH_PORT_NULL)
	      __mach_port_deallocate (__mach_task_self (), wobj);
	    break;
	  case PROT_WRITE:
	    memobj = wobj;
	    if (robj != MACH_PORT_NULL)
	      __mach_port_deallocate (__mach_task_self (), robj);
	    break;
	  case PROT_READ|PROT_WRITE:
	    if (robj == wobj)
	      {
		memobj = wobj;
		/* Remove extra reference.  */
		__mach_port_deallocate (__mach_task_self (), memobj);
	      }
	    else if (wobj == MACH_PORT_NULL && /* Not writable by mapping.  */
		     !(flags & MAP_SHARED))
	      /* The file can only be mapped for reading.  Since we are
		 making a private mapping, we will never try to write the
		 object anyway, so we don't care.  */
	      memobj = robj;
	    else
	      {
		__mach_port_deallocate (__mach_task_self (), wobj);
		return (__ptr_t) (long int) __hurd_fail (EACCES);
	      }
	    break;
	  }
	break;
	/* XXX handle MAP_NOEXTEND */
      }
    }

  /* XXX handle MAP_INHERIT */

  err = __vm_map (__mach_task_self (),
		  &mapaddr, (vm_size_t) len, (vm_address_t) 0,
		  ! (flags & MAP_FIXED),
		  memobj, (vm_offset_t) offset,
		  ! (flags & MAP_SHARED),
		  vmprot, VM_PROT_ALL,
		  (flags & MAP_SHARED) ? VM_INHERIT_SHARE : VM_INHERIT_COPY);

  if (err == KERN_NO_SPACE && (flags & MAP_FIXED))
    {
      /* XXX this is not atomic as it is in unix! */
      /* The region is already allocated; deallocate it first.  */
      err = __vm_deallocate (__mach_task_self (), mapaddr, len);
      if (! err)
	err = __vm_map (__mach_task_self (),
			&mapaddr, (vm_size_t) len, (vm_address_t) 0,
			0, memobj, (vm_offset_t) offset,
			! (flags & MAP_SHARED),
			vmprot, VM_PROT_ALL,
			(flags & MAP_SHARED) ? VM_INHERIT_SHARE
			: VM_INHERIT_COPY);
    }

  if (memobj != MACH_PORT_NULL)
    __mach_port_deallocate (__mach_task_self (), memobj);

  if (err)
    return (__ptr_t) (long int) __hurd_fail (err);

  /* Adjust the mapping address for the offset-within-page.  */
  mapaddr += pageoff;

  return (__ptr_t) mapaddr;
}