private IEnumerable <ELFProgramSegment> ReadSegments()
{
Header.IsProgramHeaderCountReasonable.CheckThrowing();
IsHeaderProgramHeaderOffsetValid.CheckThrowing();
IsHeaderProgramHeaderEntrySizeValid.CheckThrowing();
// Calculate the loadBias. It is usually just the base address except for some executable modules.
ulong loadBias = _position;
if (loadBias > 0)
{
for (uint i = 0; i < Header.ProgramHeaderCount; i++)
{
ulong programHeaderOffset = _position + Header.ProgramHeaderOffset + i * Header.ProgramHeaderEntrySize;
ELFProgramHeader header = DataSourceReader.Read <ELFProgramHeader>(programHeaderOffset);
if (header.Type == ELFProgramHeaderType.Load && header.FileOffset == 0)
{
loadBias -= header.VirtualAddress;
}
}
}
// Build the program segments
List <ELFProgramSegment> segments = new List <ELFProgramSegment>();
for (uint i = 0; i < Header.ProgramHeaderCount; i++)
{
ulong programHeaderOffset = _position + Header.ProgramHeaderOffset + i * Header.ProgramHeaderEntrySize;
segments.Add(new ELFProgramSegment(DataSourceReader, loadBias, programHeaderOffset, _isDataSourceVirtualAddressSpace));
}
return(segments);
}
public uint Read(ulong position, byte[] buffer, uint bufferOffset, uint count)
{
uint bytesRead = 0;
while (bytesRead != count)
{
int i = 0;
for (; i < _segments.Length; i++)
{
ELFProgramHeader header = _segments[i].Header;
ulong upperAddress = header.VirtualAddress + header.VirtualSize;
if (header.VirtualAddress <= position && position < upperAddress)
{
uint bytesToReadRange = (uint)Math.Min(count - bytesRead, upperAddress - position);
ulong segmentOffset = position - header.VirtualAddress;
uint bytesReadRange = _segments[i].Contents.Read(segmentOffset, buffer, bufferOffset, bytesToReadRange);
if (bytesReadRange == 0)
{
goto done;
}
position += bytesReadRange;
bufferOffset += bytesReadRange;
bytesRead += bytesReadRange;
break;
}
}
if (i == _segments.Length)
{
break;
}
}
done:
if (bytesRead == 0)
{
throw new InvalidVirtualAddressException(string.Format("Virtual address range is not mapped {0:X16} {1}", position, count));
}
// Zero the rest of the buffer if read less than requested
Array.Clear(buffer, (int)bufferOffset, (int)(count - bytesRead));
return(bytesRead);
}
public uint Read(ulong position, byte[] buffer, uint bufferOffset, uint count)
{
for (int i = 0; i < _segments.Length; i++)
{
ELFProgramHeader header = _segments[i].Header;
// FileSize == 0 means the segment isn't backed by any data
if (header.FileSize > 0 && header.VirtualAddress <= position && position + count <= header.VirtualAddress + header.VirtualSize)
{
ulong segmentOffset = position - header.VirtualAddress;
uint fileBytes = (uint)Math.Min(count, header.FileSize);
uint bytesRead = _segments[i].Contents.Read(segmentOffset, buffer, bufferOffset, fileBytes);
//zero the rest of the buffer if it is in the virtual address space but not the physical address space
if (bytesRead == fileBytes && fileBytes != count)
{
Array.Clear(buffer, (int)(bufferOffset + fileBytes), (int)(count - fileBytes));
bytesRead = count;
}
return(bytesRead);
}
}
throw new InvalidVirtualAddressException(string.Format("Virtual address range is not mapped {0:X16} {1}", position, count));
}
