// FUNCTION: Loads a segment to RAM
// RETURNS: 0 if succesful
// -1 if not successful due to registers size
public int loadRAMfromDataArrayBytes(ref byte[] data, ref PHE headerTable)
{
// if data can't fit in RAM, complain and exit program
if (RAM.Length < headerTable.p_filesz)
{
Console.WriteLine("The RAM registers size is too small. Please re-run the program with a bigger RAM memmory size");
return(-1);
}
else if (RAM.Length < headerTable.p_vaddr)
{
Console.WriteLine("The start program offset is greater than the RAM size.The RAM registers size is too small. Please re-run the program with a bigger RAM memmory size.");
return(-1);
}
else if ((RAM.Length - headerTable.p_vaddr) < headerTable.p_filesz)
{
Console.WriteLine("The RAM registers size is too small. Please re-run the program with a bigger RAM memmory size");
return(-1);
}
else
{
uint i, n = 0;
for (i = headerTable.p_vaddr; n < headerTable.p_filesz; i++, n++)
{
RAM[i] = data[n];
}
return(0);
}
}
/// FUNCTION: Open ELF file, read elf header, read each program header entr (PHE) and store segment(s) to RAM
/// if succesful elf header read, then
/// - clear memory and registers
/// - set programCounter with elf header entry point
/// - load PHEs to RAM
/// RETURNS:
/// returns -1 if failed to load segments into ram
/// returns 0 if success
public int loadSegmentsIntoRAM(string fileName)
{
try
{
using (FileStream strm = new FileStream(fileName, FileMode.Open))
{
ELF elfHeader = new ELF();
byte[] data = new byte[Marshal.SizeOf(elfHeader)];
strm.Read(data, 0, data.Length); // Read ELF header data
elfHeader = ByteArrayToStructure <ELF>(data); // Convert to struct
debugLog.WriteLineToLog("IMPORTANT: Debug logging information for developers: " + DateTime.Now);
debugLog.WriteLineToLog("Loader: in loadSegmentsIntoRAM (): Opening " + fileName + "…");
debugLog.WriteLineToLog("Loader: in loadSegmentsIntoRAM (): Program entry address: " + elfHeader.e_entry);
debugLog.WriteLineToLog("Loader: in loadSegmentsIntoRAM (): Program header offset (location in file): " + elfHeader.e_phoff);
debugLog.WriteLineToLog("Loader: in loadSegmentsIntoRAM (): Size of Program header entry: " + elfHeader.e_phentsize);
debugLog.WriteLineToLog("Loader: in loadSegmentsIntoRAM (): Number of segments: " + elfHeader.e_phnum); //NumberelfHeader.e_entry.ToString("X4"));
// clear memory, registers, nzcv flags
memory.clearMemory();
registers.clearRegisters();
registers.clearNZCVFlags();
// update program counter r15
registers.updateProgramCounter(elfHeader.e_entry);
// update stack pointer r13
registers.updateStackPointer(0x7000);
// Read all program header entries and load segments to RAM
uint nextElfHeaderOffset = elfHeader.e_phoff;
int segmentNum = 0;
for (int i = 0; i < elfHeader.e_phnum; i++, segmentNum++) // Read all program headers
{
// Read a program header
PHE headerTable = new PHE();
data = new byte[elfHeader.e_phentsize];
strm.Seek(nextElfHeaderOffset, SeekOrigin.Begin); // move position to start of next program header entry
strm.Read(data, 0, (int)elfHeader.e_phentsize); // Read ELF header data
headerTable = ByteArrayToStructure <PHE>(data); // Convert to struct
// Load PHE to RAM
strm.Seek(headerTable.p_offset, SeekOrigin.Begin); // move position to start of segment
data = new byte[headerTable.p_filesz]; // resize data
strm.Read(data, 0, (int)headerTable.p_filesz); // Read segment to data
int succesfulLoad = memory.loadRAMfromDataArrayBytes(ref data, ref headerTable);
if (succesfulLoad == -1) // return if fail to load registers, mostlikely it doesn't fit in the RAM
{
return(-1);
}
debugLog.WriteLineToLog("Loader: Segment " + segmentNum +
" - vAddress = " + headerTable.p_vaddr +
", File Offset: " + headerTable.p_offset +
", Size: " + headerTable.p_filesz);
nextElfHeaderOffset += ((uint)elfHeader.e_phentsize);
}
uint cksum = memory.ComputeRAMChecksum(null);
debugLog.WriteLineToLog("\nCurrent RAM hex digest: " + cksum);
//Console.WriteLine("\nCurrent RAM hex digest: " + cksum);
}
}
catch (Exception e)
{
debugLog.WriteLineToLog("Loader: in loadSegmentsIntoRAM(): File cannot be opened: " + e.Message);
//Console.WriteLine("For help try: armmemory.exe --help");
MessageBox.Show(e.Message, "Error Openning Executable File",
MessageBoxButtons.OK, MessageBoxIcon.Error);
return(-1);
}
return(0);
}
