/// <summary>
/// take a hash of the current full contents of the block, including unreadable areas
/// but not uncommitted areas
/// </summary>
/// <exception cref="InvalidOperationException">
/// <see cref="MemoryBlock.Active"/> is <see langword="false"/> or failed to make memory read-only
/// </exception>
public byte[] FullHash()
{
if (!Active)
{
throw new InvalidOperationException("Not active");
}
// temporarily switch the committed parts to `R` so we can read them
if (CommittedSize > 0)
{
_pal.Protect(Start, CommittedSize, Protection.R);
}
var ret = WaterboxUtils.Hash(GetStream(Start, CommittedSize, false));
ProtectAll();
return(ret);
}
/// <summary>restore all recorded protections</summary>
private void ProtectAll()
{
if (CommittedSize == 0)
{
return;
}
int ps = 0;
int pageLimit = (int)(CommittedSize >> WaterboxUtils.PageShift);
for (int i = 0; i < pageLimit; i++)
{
if (i == pageLimit - 1 || _pageData[i] != _pageData[i + 1] || _dirtydata[i] != _dirtydata[i + 1])
{
ulong zstart = GetStartAddr(ps);
ulong zend = GetStartAddr(i + 1);
var prot = _pageData[i];
// adjust frontend notion of prot to the PAL layer's expectation
if (prot == Protection.RW_Stack)
{
if (!_sealed)
{
// don't activate this protection yet
prot = Protection.RW;
}
else
{
var didChange = (_dirtydata[i] & WriteDetectionStatus.DidChange) != 0;
if (didChange)
{
// don't needlessly retrigger
prot = Protection.RW;
}
}
}
else if (prot == Protection.RW_Invisible)
{
// this never matters to the backend
prot = Protection.RW;
}
else if (_sealed && prot == Protection.RW)
{
var didChange = (_dirtydata[i] & WriteDetectionStatus.DidChange) != 0;
if (!didChange)
{
// set to trigger if we have not before
prot = Protection.R;
}
}
_pal.Protect(zstart, zend - zstart, prot);
ps = i + 1;
}
}
}
/// <summary>set r/w/x protection on a portion of memory. rounded to encompassing pages</summary>
/// <exception cref="InvalidOperationException">failed to protect memory</exception>
public void Protect(ulong start, ulong length, Protection prot)
{
if (length == 0)
{
return;
}
// Note: asking for prot.none on memory that was not previously committed, commits it
var computedStart = WaterboxUtils.AlignDown(start);
var computedEnd = WaterboxUtils.AlignUp(start + length);
var computedLength = computedEnd - computedStart;
_pal.Protect(computedStart, computedLength, prot);
}
/// <summary>restore all recorded protections</summary>
private void ProtectAll()
{
if (CommittedSize == 0)
{
return;
}
int ps = 0;
int pageLimit = (int)(CommittedSize >> WaterboxUtils.PageShift);
for (int i = 0; i < pageLimit; i++)
{
if (i == pageLimit - 1 || _pageData[i] != _pageData[i + 1])
{
ulong zstart = GetStartAddr(ps);
ulong zend = GetStartAddr(i + 1);
var prot = _pageData[i];
_pal.Protect(zstart, zend - zstart, prot);
ps = i + 1;
}
}
}