public void ReadSegmentHeaders()
{
byte[] segmentsData = new byte[header.ProgHeaderEntrySize * header.ProgHeaderNumEntries];
theStream.Position = header.ProgHeaderTableOffset;
int bytesRead = theStream.Read(segmentsData, 0, segmentsData.Length);
if (bytesRead == segmentsData.Length)
{
uint offset = 0;
while (offset < segmentsData.Length)
{
ELFSegmentHeader newHeader = new ELFSegmentHeader(segmentsData, ref offset);
ELFSegment newSegment = ELFSegment.GetSegment(newHeader);
newSegment.Read(theStream);
Segments.Add(newSegment);
}
//BasicConsole.WriteLine();
#region Segments Output
//for (int i = 0; i < Segments.Count; i++)
//{
// ELFSegment theSegment = (ELFSegment)Segments[i];
// ELFSegmentHeader theHeader = theSegment.Header;
// BasicConsole.WriteLine("ELF Segment: ");
// BasicConsole.Write(" - Type : ");
// BasicConsole.WriteLine((uint)theHeader.Type);
// BasicConsole.Write(" - File offset : ");
// BasicConsole.WriteLine(theHeader.FileOffset);
// BasicConsole.Write(" - Virtual address : ");
// BasicConsole.WriteLine((uint)theHeader.VAddr);
// BasicConsole.Write(" - Physical address : ");
// BasicConsole.WriteLine((uint)theHeader.PAddr);
// BasicConsole.Write(" - File size : ");
// BasicConsole.WriteLine(theHeader.FileSize);
// BasicConsole.Write(" - Memory size : ");
// BasicConsole.WriteLine(theHeader.MemSize);
// BasicConsole.Write(" - Flags : ");
// BasicConsole.WriteLine((uint)theHeader.Flags);
// BasicConsole.Write(" - Alignment : ");
// BasicConsole.WriteLine(theHeader.Align);
// Hardware.Processes.Thread.Sleep(500);
// TODO: Use system call not direct call
//}
#endregion
}
else
{
ExceptionMethods.Throw(new FOS_System.Exception("Failed to read segments table data from file!"));
}
}
public void Load(bool UserMode)
{
bool OK = true;
try
{
bool DynamicLinkingRequired = false;
ThreadStartMethod mainMethod = (ThreadStartMethod)Utilities.ObjectUtilities.GetObject(theFile.Header.EntryPoint);
theProcess = ProcessManager.CreateProcess(
mainMethod, theFile.TheFile.Name, UserMode);
uint threadStackVirtAddr = (uint)((Thread)theProcess.Threads[0]).State->ThreadStackTop - 4092;
uint threadStackPhysAddr = (uint)Hardware.VirtMemManager.GetPhysicalAddress(threadStackVirtAddr);
ProcessManager.CurrentProcess.TheMemoryLayout.AddDataPage(threadStackPhysAddr, threadStackVirtAddr);
// Load the ELF segments (i.e. the program code and data)
BaseAddress = theFile.BaseAddress;
LoadSegments(theFile, ref OK, ref DynamicLinkingRequired, BaseAddress);
//BasicConsole.WriteLine();
#region Relocations
// Useful articles / specifications on Relocations:
// - Useful / practical explanation of various relocation types: http://eli.thegreenplace.net/2011/08/25/load-time-relocation-of-shared-libraries/#id20
// - Orcale : ELF Specification copy: http://docs.oracle.com/cd/E23824_01/html/819-0690/chapter6-54839.html
if (DynamicLinkingRequired)
{
Console.Default.WriteLine("Dynamic Linking");
BasicConsole.WriteLine("Dynamic Linking");
ELFDynamicSection dynamicSection = theFile.DynamicSection;
ELFDynamicSymbolTableSection dynamicSymbolsSection = theFile.DynamicSymbolsSection;
ELFStringTable DynamicsStringTable = new ELFStringTable(
dynamicSection.StrTabDynamic.Val_Ptr, dynamicSection.StrTabSizeDynamic.Val_Ptr);
for (uint i = 0; i < dynamicSection.Dynamics.Count; i++)
{
ELFDynamicSection.Dynamic theDyn = dynamicSection[i];
//BasicConsole.WriteLine(" - Dynamic : ");
//BasicConsole.Write(" - Tag : ");
//BasicConsole.WriteLine((int)theDyn.Tag);
//BasicConsole.Write(" - Value or Pointer : ");
//BasicConsole.WriteLine(theDyn.Val_Ptr);
if (theDyn.Tag == ELFDynamicSection.DynamicTag.Needed)
{
BasicConsole.Write(" - Needed library name : ");
FOS_System.String libFullPath = DynamicsStringTable[theDyn.Val_Ptr];
Console.Default.WriteLine(libFullPath);
BasicConsole.WriteLine(libFullPath);
FOS_System.String libFileName = (FOS_System.String)libFullPath.Split('\\').Last();
libFileName = (FOS_System.String)libFileName.Split('/').Last();
FOS_System.String libTestPath = theFile.TheFile.Parent.GetFullPath() + libFileName;
File sharedObjectFile = File.Open(libTestPath);
if (sharedObjectFile == null)
{
Console.Default.WarningColour();
Console.Default.WriteLine("Failed to find needed library file!");
BasicConsole.WriteLine("Failed to find needed library file!");
Console.Default.DefaultColour();
OK = false;
}
else
{
Console.Default.WriteLine("Found library file. Loading library...");
BasicConsole.WriteLine("Found library file. Loading library...");
ELFSharedObject sharedObject = DynamicLinkerLoader.LoadLibrary_FromELFSO(sharedObjectFile, this);
SharedObjectDependencies.Add(sharedObject);
Console.Default.WriteLine("Library loaded.");
BasicConsole.WriteLine("Library loaded.");
}
}
}
Console.Default.WriteLine("Library Relocations");
BasicConsole.WriteLine("Library Relocations");
// Perform relocation / dynamic linking of all libraries
for (int i = 0; i < SharedObjectDependencies.Count; i++)
{
ELFSharedObject SO = (ELFSharedObject)SharedObjectDependencies[i];
//BasicConsole.WriteLine("Shared Object base address : " + (FOS_System.String)SO.BaseAddress);
//BasicConsole.WriteLine("Shared Object file base address : " + (FOS_System.String)SO.TheFile.BaseAddress);
List SOSections = SO.TheFile.Sections;
for (int j = 0; j < SOSections.Count; j++)
{
ELFSection SOSection = (ELFSection)SOSections[j];
if (SOSection is ELFRelocationTableSection)
{
//BasicConsole.WriteLine(" - Normal Relocation");
ELFRelocationTableSection relocTableSection = (ELFRelocationTableSection)SOSection;
ELFSymbolTableSection symbolTable = (ELFSymbolTableSection)SO.TheFile.Sections[relocTableSection.SymbolTableSectionIndex];
ELFStringTableSection symbolNamesTable = (ELFStringTableSection)SO.TheFile.Sections[symbolTable.StringsSectionIndex];
List Relocations = relocTableSection.Relocations;
for (int k = 0; k < Relocations.Count; k++)
{
// Reference: http://docs.oracle.com/cd/E19683-01/817-3677/chapter6-26/index.html
ELFRelocationTableSection.Relocation relocation = (ELFRelocationTableSection.Relocation)Relocations[k];
if (relocation.Type == ELFRelocationTableSection.RelocationType.R_386_NONE)
{
continue;
}
uint *resolvedRelLocation = (uint *)(SO.BaseAddress + (relocation.Offset - SO.TheFile.BaseAddress));
ELFSymbolTableSection.Symbol symbol = (ELFSymbolTableSection.Symbol)symbolTable[relocation.Symbol];
FOS_System.String symbolName = symbolNamesTable[symbol.NameIdx];
//BasicConsole.WriteLine("Relocation:");
////BasicConsole.WriteLine(" > Symbol index : " + (FOS_System.String)relocation.Symbol);
//BasicConsole.WriteLine(" > Type : " + (FOS_System.String)(uint)relocation.Type);
//BasicConsole.WriteLine(" > Offset : " + (FOS_System.String)(uint)relocation.Offset);
//BasicConsole.WriteLine(((FOS_System.String)" > Resolved location address: ") + (uint)resolvedRelLocation);
////BasicConsole.WriteLine(((FOS_System.String)" > Resolved location start value: ") + *resolvedRelLocation);
//BasicConsole.Write(" > Symbol name : ");
//BasicConsole.WriteLine(symbolName);
uint newValue = 0;
switch (relocation.Type)
{
case ELFRelocationTableSection.RelocationType.R_386_32:
newValue = GetSymbolAddress(symbol, symbolName) + *resolvedRelLocation;
break;
case ELFRelocationTableSection.RelocationType.R_386_PC32:
newValue = GetSymbolAddress(symbol, symbolName) + *resolvedRelLocation - (uint)resolvedRelLocation;
break;
case ELFRelocationTableSection.RelocationType.R_386_RELATIVE:
newValue = SO.BaseAddress + *resolvedRelLocation;
break;
//TODO: Support more relocation types
default:
Console.Default.WarningColour();
Console.Default.Write("WARNING: Unrecognised relocation type! (");
Console.Default.Write_AsDecimal((uint)relocation.Type);
Console.Default.WriteLine(")");
Console.Default.DefaultColour();
BasicConsole.Write("WARNING: Unrecognised relocation type! (");
BasicConsole.Write((uint)relocation.Type);
BasicConsole.WriteLine(")");
break;
}
*resolvedRelLocation = newValue;
//BasicConsole.WriteLine(" > New value: " + (FOS_System.String)(newValue));
//BasicConsole.WriteLine(" > Resolved location end value: " + (FOS_System.String)(*resolvedRelLocation));
}
}
else if (SOSection is ELFRelocationAddendTableSection)
{
//BasicConsole.WriteLine(" - Addend Relocation");
ELFRelocationAddendTableSection relocTableSection = (ELFRelocationAddendTableSection)SOSection;
ELFSymbolTableSection symbolTable = (ELFSymbolTableSection)SO.TheFile.Sections[relocTableSection.SymbolTableSectionIndex];
ELFStringTableSection symbolNamesTable = (ELFStringTableSection)SO.TheFile.Sections[symbolTable.StringsSectionIndex];
List Relocations = relocTableSection.Relocations;
for (int k = 0; k < Relocations.Count; k++)
{
ELFRelocationAddendTableSection.RelocationAddend relocation = (ELFRelocationAddendTableSection.RelocationAddend)Relocations[k];
if (relocation.Type == ELFRelocationTableSection.RelocationType.R_386_NONE)
{
continue;
}
ELFSymbolTableSection.Symbol symbol = (ELFSymbolTableSection.Symbol)symbolTable[relocation.Symbol];
FOS_System.String symbolName = symbolNamesTable[symbol.NameIdx];
uint *resolvedRelLocation = (uint *)(SO.BaseAddress + (relocation.Offset - SO.TheFile.BaseAddress));
//BasicConsole.WriteLine("Relocation:");
////BasicConsole.WriteLine(" > Symbol index : " + (FOS_System.String)relocation.Symbol);
//BasicConsole.WriteLine(" > Type : " + (FOS_System.String)(uint)relocation.Type);
//BasicConsole.WriteLine(" > Offset : " + (FOS_System.String)(uint)relocation.Offset);
//BasicConsole.WriteLine(((FOS_System.String)" > Resolved location address: ") + (uint)resolvedRelLocation);
////BasicConsole.WriteLine(((FOS_System.String)" > Resolved location start value: ") + *resolvedRelLocation);
//BasicConsole.Write(" > Symbol name : ");
//BasicConsole.WriteLine(symbolName);
uint newValue = 0;
switch (relocation.Type)
{
//TODO: Support more relocation types
default:
Console.Default.WarningColour();
Console.Default.Write("WARNING: Unrecognised relocation type! (");
Console.Default.Write_AsDecimal((uint)relocation.Type);
Console.Default.WriteLine(")");
Console.Default.DefaultColour();
BasicConsole.Write("WARNING: Unrecognised relocation type! (");
BasicConsole.Write((uint)relocation.Type);
BasicConsole.WriteLine(")");
break;
}
*resolvedRelLocation = newValue;
//BasicConsole.WriteLine(" > New value: " + (FOS_System.String)(newValue));
//BasicConsole.WriteLine(" > Resolved location end value: " + (FOS_System.String)(*resolvedRelLocation));
}
}
}
}
Console.Default.WriteLine("Executable Relocations");
BasicConsole.WriteLine("Executable Relocations");
//BasicConsole.WriteLine("Executable base address : " + (FOS_System.String)BaseAddress);
//BasicConsole.WriteLine("Executable file base address : " + (FOS_System.String)theFile.BaseAddress);
// Perform dynamic linking of executable
List ExeSections = theFile.Sections;
for (int j = 0; j < ExeSections.Count; j++)
{
ELFSection ExeSection = (ELFSection)ExeSections[j];
if (ExeSection is ELFRelocationTableSection)
{
//BasicConsole.WriteLine(" - Normal Relocations");
ELFRelocationTableSection relocTableSection = (ELFRelocationTableSection)ExeSection;
ELFSymbolTableSection symbolTable = (ELFSymbolTableSection)theFile.Sections[relocTableSection.SymbolTableSectionIndex];
ELFStringTableSection symbolNamesTable = (ELFStringTableSection)theFile.Sections[symbolTable.StringsSectionIndex];
List Relocations = relocTableSection.Relocations;
for (int k = 0; k < Relocations.Count; k++)
{
ELFRelocationTableSection.Relocation relocation = (ELFRelocationTableSection.Relocation)Relocations[k];
if (relocation.Type == ELFRelocationTableSection.RelocationType.R_386_NONE)
{
continue;
}
uint *resolvedRelLocation = (uint *)(BaseAddress + (relocation.Offset - theFile.BaseAddress));
ELFSymbolTableSection.Symbol symbol = (ELFSymbolTableSection.Symbol)symbolTable[relocation.Symbol];
FOS_System.String symbolName = symbolNamesTable[symbol.NameIdx];
//BasicConsole.WriteLine("Relocation:");
////BasicConsole.WriteLine(" > Symbol index : " + (FOS_System.String)relocation.Symbol);
//BasicConsole.WriteLine(" > Type : " + (FOS_System.String)(uint)relocation.Type);
//BasicConsole.WriteLine(" > Offset : " + (FOS_System.String)(uint)relocation.Offset);
//BasicConsole.WriteLine(((FOS_System.String)" > Resolved location address: ") + (uint)resolvedRelLocation);
////BasicConsole.WriteLine(((FOS_System.String)" > Resolved location start value: ") + *resolvedRelLocation);
//BasicConsole.Write(" > Symbol name : ");
//BasicConsole.WriteLine(symbolName);
bool setFromNewValue = true;
uint newValue = 0;
switch (relocation.Type)
{
//TODO: Support more relocation types
case ELFRelocationTableSection.RelocationType.R_386_JMP_SLOT:
newValue = GetSymbolAddress(symbol, symbolName);
break;
case ELFRelocationTableSection.RelocationType.R_386_COPY:
// Created by the link-editor for dynamic executables to preserve a read-only text segment.
// Its offset member refers to a location in a writable segment. The symbol table index
// specifies a symbol that should exist both in the current object file and in a shared object.
// During execution, the runtime linker copies data associated with the shared object's symbol
// to the location specified by the offset.
// See Copy Relocations:
// http://docs.oracle.com/cd/E19683-01/817-3677/6mj8mbtbs/index.html#chapter4-84604
setFromNewValue = false;
uint symbolAddress = 0;
uint symbolSize = 0;
if (GetSymbolAddressAndSize(symbol, symbolName, ref symbolAddress, ref symbolSize))
{
byte *symbolValuePtr = (byte *)symbolAddress;
//BasicConsole.Write(" > Symbol size : ");
//BasicConsole.WriteLine(symbolSize);
for (int i = 0; i < symbolSize; i++)
{
resolvedRelLocation[i] = symbolValuePtr[i];
}
}
else
{
BasicConsole.WriteLine("Failed to get symbol address and size for R_386_COPY relocation!");
}
break;
default:
Console.Default.WarningColour();
Console.Default.Write("WARNING: Unrecognised relocation type! (");
Console.Default.Write_AsDecimal((uint)relocation.Type);
Console.Default.WriteLine(")");
Console.Default.DefaultColour();
BasicConsole.Write("WARNING: Unrecognised relocation type! (");
BasicConsole.Write((uint)relocation.Type);
BasicConsole.WriteLine(")");
break;
}
if (setFromNewValue)
{
*resolvedRelLocation = newValue;
//BasicConsole.WriteLine(" > New value: " + (FOS_System.String)(newValue));
//BasicConsole.WriteLine(" > Resolved location end value: " + (FOS_System.String)(*resolvedRelLocation));
}
}
}
else if (ExeSection is ELFRelocationAddendTableSection)
{
//BasicConsole.WriteLine(" - Addend Relocations");
ELFRelocationAddendTableSection relocTableSection = (ELFRelocationAddendTableSection)ExeSection;
ELFSymbolTableSection symbolTable = (ELFSymbolTableSection)theFile.Sections[relocTableSection.SymbolTableSectionIndex];
ELFStringTableSection symbolNamesTable = (ELFStringTableSection)theFile.Sections[symbolTable.StringsSectionIndex];
List Relocations = relocTableSection.Relocations;
for (int k = 0; k < Relocations.Count; k++)
{
ELFRelocationAddendTableSection.RelocationAddend relocation = (ELFRelocationAddendTableSection.RelocationAddend)Relocations[k];
if (relocation.Type == ELFRelocationTableSection.RelocationType.R_386_NONE)
{
continue;
}
uint *resolvedRelLocation = (uint *)(BaseAddress + (relocation.Offset - theFile.BaseAddress));
ELFSymbolTableSection.Symbol symbol = (ELFSymbolTableSection.Symbol)symbolTable[relocation.Symbol];
FOS_System.String symbolName = symbolNamesTable[symbol.NameIdx];
//BasicConsole.WriteLine("Relocation:");
////BasicConsole.WriteLine(" > Symbol index : " + (FOS_System.String)relocation.Symbol);
//BasicConsole.WriteLine(" > Type : " + (FOS_System.String)(uint)relocation.Type);
//BasicConsole.WriteLine(" > Offset : " + (FOS_System.String)(uint)relocation.Offset);
//BasicConsole.WriteLine(((FOS_System.String)" > Resolved location address: ") + (uint)resolvedRelLocation);
////BasicConsole.WriteLine(((FOS_System.String)" > Resolved location start value: ") + *resolvedRelLocation);
//BasicConsole.Write(" > Symbol name : ");
//BasicConsole.WriteLine(symbolName);
uint newValue = 0;
switch (relocation.Type)
{
//TODO: Support more relocation types
default:
Console.Default.WarningColour();
Console.Default.Write("WARNING: Unrecognised relocation type! (");
Console.Default.Write_AsDecimal((uint)relocation.Type);
Console.Default.WriteLine(")");
Console.Default.DefaultColour();
BasicConsole.Write("WARNING: Unrecognised relocation type! (");
BasicConsole.Write((uint)relocation.Type);
BasicConsole.WriteLine(")");
break;
}
*resolvedRelLocation = newValue;
//BasicConsole.WriteLine(" > New value: " + (FOS_System.String)(newValue));
//BasicConsole.WriteLine(" > Resolved location end value: " + (FOS_System.String)(*resolvedRelLocation));
}
}
}
// TODO: Call Init functions of libraries
}
// Unmap processes' memory from current processes' memory
for (int i = 0; i < SharedObjectDependencies.Count; i++)
{
ELFSharedObject SO = (ELFSharedObject)SharedObjectDependencies[i];
uint FileBaseAddress = SO.TheFile.BaseAddress;
uint MemBaseAddress = SO.BaseAddress;
List SOSegments = SO.TheFile.Segments;
for (int j = 0; j < SOSegments.Count; j++)
{
ELFSegment SOSegment = (ELFSegment)SOSegments[j];
ProcessManager.CurrentProcess.TheMemoryLayout.RemovePage(
(MemBaseAddress + ((uint)SOSegment.Header.VAddr - FileBaseAddress)) & 0xFFFFF000);
}
}
{
uint FileBaseAddress = theFile.BaseAddress;
uint MemBaseAddress = BaseAddress;
List ExeSegments = theFile.Segments;
for (int j = 0; j < ExeSegments.Count; j++)
{
ELFSegment ExeSegment = (ELFSegment)ExeSegments[j];
ProcessManager.CurrentProcess.TheMemoryLayout.RemovePage(
(MemBaseAddress + ((uint)ExeSegment.Header.VAddr - FileBaseAddress)) & 0xFFFFF000);
}
}
#endregion
ProcessManager.CurrentProcess.TheMemoryLayout.RemovePage(threadStackVirtAddr);
}
finally
{
if (!OK)
{
theProcess = null;
}
}
}
public void LoadSegments(ELFFile fileToLoadFrom, ref bool OK, ref bool DynamicLinkingRequired, uint memBaseAddress)
{
uint fileBaseAddress = fileToLoadFrom.BaseAddress;
List Segments = fileToLoadFrom.Segments;
for (int i = 0; i < Segments.Count; i++)
{
ELFSegment segment = (ELFSegment)Segments[i];
if (segment.Header.Type == ELFSegmentType.Interp ||
segment.Header.Type == ELFSegmentType.Dynamic)
{
DynamicLinkingRequired = true;
}
else if (segment.Header.Type == ELFSegmentType.Load)
{
int bytesRead = segment.Read(fileToLoadFrom.TheStream);
if (bytesRead != segment.Header.FileSize)
{
OK = false;
ExceptionMethods.Throw(new FOS_System.Exception("Error loading ELF segments! Failed to load correct segment bytes from file."));
}
byte *destMemPtr = (segment.Header.VAddr - fileBaseAddress) + memBaseAddress;
byte *pageAlignedDestMemPtr = (byte *)((uint)destMemPtr & 0xFFFFF000);
Console.Default.Write(" Loading segment from ");
Console.Default.Write_AsDecimal((uint)segment.Header.VAddr);
Console.Default.Write(" to ");
Console.Default.WriteLine_AsDecimal((uint)destMemPtr);
BasicConsole.Write(" Loading segment from ");
BasicConsole.Write((uint)segment.Header.VAddr);
BasicConsole.Write(" to ");
BasicConsole.WriteLine((uint)destMemPtr);
Hardware.Processes.Thread.Sleep(1000);
uint copyOffset = (uint)(destMemPtr - pageAlignedDestMemPtr);
uint copyFromOffset = 0;
bool executable = (segment.Header.Flags & ELFFlags.Executable) != 0;
for (uint pageOffset = 0; pageOffset < segment.Header.MemSize; pageOffset += 4096)
{
uint physPageAddr = Hardware.VirtMemManager.FindFreePhysPage();
uint virtPageAddr = (uint)pageAlignedDestMemPtr + pageOffset;
Hardware.VirtMemManager.Map(
physPageAddr,
virtPageAddr,
4096,
theProcess.UserMode ? Hardware.VirtMem.VirtMemImpl.PageFlags.None : Hardware.VirtMem.VirtMemImpl.PageFlags.KernelOnly);
ProcessManager.CurrentProcess.TheMemoryLayout.AddDataPage(physPageAddr, virtPageAddr);
if (executable)
{
theProcess.TheMemoryLayout.AddCodePage(physPageAddr, virtPageAddr);
}
else
{
theProcess.TheMemoryLayout.AddDataPage(physPageAddr, virtPageAddr);
}
uint copySize = FOS_System.Math.Min((uint)bytesRead, 4096 - copyOffset);
if (copySize > 0)
{
Utilities.MemoryUtils.MemCpy_32(
(byte *)(virtPageAddr + copyOffset),
((byte *)Utilities.ObjectUtilities.GetHandle(segment.Data)) + FOS_System.Array.FieldsBytesSize + pageOffset - copyFromOffset,
copySize);
bytesRead -= (int)copySize;
}
for (uint j = copySize + copyOffset; j < 4096; j++)
{
*(byte *)(virtPageAddr + j) = 0;
}
if (copyOffset > 0)
{
copyFromOffset += copyOffset;
copyOffset = 0;
}
}
}
}
}
