/// <summary>
/// Parse the section headers.
/// </summary>
private void ParseSectionHdrs()
{
UInt32 byteSize, wordSize, numBytesInSectionHdr;
UInt64 flags;
ELF_SectionHeader secHdr;
EndianBinaryReader ebr = new EndianBinaryReader(binFile, endian);
numBytesInSectionHdr = hdr.e_shentsize;
Debug.DebugMSG("Parsing ELF Sections Headers");
if (sectionCount == (UInt32) ELF_SectionIndex.SHN_UNDEF)
{
// Get the actual number of sections from the sh_size field of the
// 0th section header table entry
secHdr = ReadSectionHeader(0);
sectionCount = (UInt32) secHdr.sh_size;
headerRef["numSectionHdrs"] = (UInt32) secHdr.sh_size;
}
// Get Section Header String Table Section Header Index and Section Header String Table Section Address
if (hdr.e_shstrndx == (UInt16) ELF_SectionIndex.SHN_UNDEF)
{
headerRef["stringTableAddr"] = null;
headerRef["stringHeaderTableIndex"] = null;
secHdr = new ELF_SectionHeader();
}
else if (hdr.e_shstrndx == (UInt16) ELF_SectionIndex.SHN_XINDEX)
{
secHdr = ReadSectionHeader(0);
headerRef["stringHeaderTableIndex"] = (UInt32) secHdr.sh_link;
secHdr = ReadSectionHeader((UInt32) headerRef["stringHeaderTableIndex"]);
headerRef["stringTableAddr"] = (UInt64) secHdr.sh_addr;
}
else
{
headerRef["stringHeaderTableIndex"] = (UInt32) hdr.e_shstrndx;
secHdr = ReadSectionHeader((UInt32) headerRef["stringHeaderTableIndex"]);
headerRef["stringTableAddr"] = (UInt64) (secHdr.sh_offset);
}
Debug.DebugMSG("Section Header Table Index for Section Header String Table: " + (UInt32)headerRef["stringHeaderTableIndex"]);
Debug.DebugMSG("String Section Start Addr: 0x" + ((UInt64)headerRef["stringTableAddr"]).ToString("X8"));
// Verify that the section header string table section is flagged as a string section
flags = (UInt64) secHdr.sh_flags;
Debug.DebugMSG("secHdr.sh_flags = " + secHdr.sh_flags.ToString());
if ( ( flags & ((UInt64) ELF_SectionFlag.SHF_STRINGS) ) == 0 )
{
Debug.DebugMSG("WARNING: Section Header String Section is not flagged with SHF_STRINGS");
}
if (secHdr.sh_type != ELF_SectionType.SHT_STRTAB)
{
throw new Exception("Section Header String Section is not of type SHT_STRTAB.");
}
if ( hdr.e_phnum == 0x0)
{
throw new Exception("Load addresses cannot be calculated without program header.");
}
// Cycle through all sections, collecting info about each (name, type, etc.)
sectionRef = new Hashtable[sectionCount];
sections = new ObjectSection[sectionCount];
for (UInt32 secNum = 0; secNum < sectionCount; secNum++)
{
sectionRef[secNum] = new Hashtable();
sections[secNum] = new ObjectSection();
secHdr = ReadSectionHeader((UInt32) secNum);
ebr.BaseStream.Seek((Int64)(secHdr.sh_name + (UInt64)headerRef["stringTableAddr"]), SeekOrigin.Begin);
sectionRef[secNum]["name"] = ELF_getStringFromStringTable();
sectionRef[secNum]["type"] = (ELF_SectionType) secHdr.sh_type;
sectionRef[secNum]["phyAddr"] = (UInt64) secHdr.sh_addr;
sectionRef[secNum]["virAddr"] = (UInt64) secHdr.sh_addr;
sectionRef[secNum]["fileAddr"] = (UInt64) secHdr.sh_offset;
byteSize = (UInt32) secHdr.sh_size;
wordSize = (byteSize + 3) >> 2;
byteSize = wordSize << 2;
sectionRef[secNum]["byteSize"] = byteSize;
sectionRef[secNum]["wordSize"] = wordSize;
sectionRef[secNum]["flags"] = (UInt64) secHdr.sh_flags;
flags = (UInt64) sectionRef[secNum]["flags"];
// FIXME: Check to see if section should be copied to target
sectionRef[secNum]["copyToTarget"] = false;
if ( ( ((UInt64) sectionRef[secNum]["phyAddr"]) != 0 ) &&
( ((UInt32) sectionRef[secNum]["byteSize"]) != 0 ) &&
( ELF_SectionType.SHT_NULL != (ELF_SectionType)sectionRef[secNum]["type"] ) &&
( ELF_SectionType.SHT_NOBITS != (ELF_SectionType)sectionRef[secNum]["type"] ) &&
( ELF_SectionType.SHT_SYMTAB != (ELF_SectionType)sectionRef[secNum]["type"] ) &&
( ELF_SectionType.SHT_DYNSYM != (ELF_SectionType)sectionRef[secNum]["type"] ) &&
( ELF_SectionType.SHT_STRTAB != (ELF_SectionType)sectionRef[secNum]["type"] ) )
{
if ( ( ELF_SectionType.SHT_PROGBITS == (ELF_SectionType)sectionRef[secNum]["type"] ) &&
( (flags | ((UInt64) ELF_SectionFlag.SHF_ALLOC)) != 0x0 ) )
{
headerRef["numTargetSections"] = ((UInt32)headerRef["numTargetSections"]) + 1;
sectionRef[secNum]["copyToTarget"] = true;
}
}
// If we think this section should be copied to target, make sure it is
// in a loadable ELF program segment. If it is, then update physical
// and virtual addresses. If not, then mark it as such.
if ((Boolean) sectionRef[secNum]["copyToTarget"])
{
Boolean segmentFoundForSection = false;
for (UInt32 segmentNum = 0; segmentNum < (UInt32)hdr.e_phnum; segmentNum++)
{
ELF_SegmentHeader segmentHdr = ReadSegmentHeader((UInt32) segmentNum);
// If the segment is of load type, check to see if the current section resides in it
if (segmentHdr.p_type == ELF_SegmentType.PT_LOAD)
{
// Check if data is in the file, and if so then check if the section
// is within this current segment
if ( ( segmentHdr.p_filesz != 0 ) &&
( segmentHdr.p_vaddr <= (UInt64) secHdr.sh_addr) &&
( (segmentHdr.p_vaddr + segmentHdr.p_filesz) > (UInt64) secHdr.sh_addr) &&
( segmentHdr.p_offset <= (UInt64) secHdr.sh_offset) &&
( (segmentHdr.p_offset + segmentHdr.p_filesz) > (UInt64) secHdr.sh_offset) )
{
sectionRef[secNum]["phyAddr"] = (UInt64) segmentHdr.p_paddr + ( secHdr.sh_addr - segmentHdr.p_vaddr);
segmentFoundForSection = true;
}
}
}
if (!segmentFoundForSection)
{
// This section is not actually in a loadable ELF program segment, indicate that
sectionRef[secNum]["copyToTarget"] = false;
}
}
sections[secNum].name = (String) sectionRef[secNum]["name"];
sections[secNum].size = (UInt32) sectionRef[secNum]["byteSize"];
sections[secNum].runAddr = (UInt64) sectionRef[secNum]["virAddr"];
sections[secNum].loadAddr = (UInt64) sectionRef[secNum]["phyAddr"];
sections[secNum].isLoadable = (Boolean) sectionRef[secNum]["copyToTarget"];
if (sections[secNum].isLoadable)
{
loadableSectionCount++;
}
sections[secNum].binFileAddr = (UInt64) sectionRef[secNum]["fileAddr"];
Debug.DebugMSG("ObjectSection sections[" + secNum + "] = \n{");
Debug.DebugMSG("\tname = " + sections[secNum].name + ",");
Debug.DebugMSG("\tsize = " + sections[secNum].size.ToString("X8") + ",");
Debug.DebugMSG("\trunAddr = " + sections[secNum].runAddr.ToString("X8") + ",");
Debug.DebugMSG("\tloadAddr = " + sections[secNum].loadAddr.ToString("X8") + ",");
Debug.DebugMSG("\tisLoadable = " + sections[secNum].isLoadable + ",");
Debug.DebugMSG("\tbinFileAddr = " + sections[secNum].binFileAddr.ToString("X8"));
Debug.DebugMSG("}");
}
// Fill in the loadableSections array
loadableSections = new ObjectSection[loadableSectionCount];
for (UInt32 secNum = 0,loadableSecNum=0; secNum < sectionCount; secNum++)
{
if (sections[secNum].isLoadable)
{
loadableSections[loadableSecNum] = sections[secNum];
loadableSecNum++;
}
}
// Finally, sort the loadable sections array by load address
Array.Sort<ObjectSection>(loadableSections);
Debug.DebugMSG("Parse Section Headers Done");
}
/// <summary>
/// Read the section header from the section header table
/// </summary>
private ELF_SectionHeader ReadSectionHeader(UInt32 index)
{
EndianBinaryReader ebr = new EndianBinaryReader(binFile, endian);
ELF_SectionHeader sectionHeader = new ELF_SectionHeader();
// Seek to the start of the section header in section header table
binFile.Seek((Int64)(hdr.e_shentsize * index + hdr.e_shoff), SeekOrigin.Begin);
//Debug.DebugMSG( "Header for Section["+index+"] = \n{");
sectionHeader.sh_name = ebr.ReadUInt32();
sectionHeader.sh_type = (ELF_SectionType) ebr.ReadUInt32();
//Debug.DebugMSG( " Section Name Index : " + sectionHeader.sh_name);
//Debug.DebugMSG( " Section Type : " + sectionHeader.sh_type);
if (ELF_FileClass.ELFCLASS_32 == hdr.e_ident.fileClass)
{
sectionHeader.sh_flags = (UInt64) ebr.ReadUInt32();
sectionHeader.sh_addr = (UInt64) ebr.ReadUInt32();
sectionHeader.sh_offset = (UInt64) ebr.ReadUInt32();
sectionHeader.sh_size = (UInt64) ebr.ReadUInt32();
//Debug.DebugMSG( " Section Flags : 0x" + sectionHeader.sh_flags.ToString("X8"));
//Debug.DebugMSG( " Section Address : 0x" + sectionHeader.sh_addr.ToString("X8"));
//Debug.DebugMSG( " Section Offset : 0x" + sectionHeader.sh_offset.ToString("X8"));
//Debug.DebugMSG( " Section Size : 0x" + sectionHeader.sh_size.ToString("X8"));
}
else
{
sectionHeader.sh_flags = ebr.ReadUInt64();
sectionHeader.sh_addr = ebr.ReadUInt64();
sectionHeader.sh_offset = ebr.ReadUInt64();
sectionHeader.sh_size = ebr.ReadUInt64();
//Debug.DebugMSG( " Section Flags : 0x" + sectionHeader.sh_flags.ToString("X16"));
//Debug.DebugMSG( " Section Address : 0x" + sectionHeader.sh_addr.ToString("X16"));
//Debug.DebugMSG( " Section Offset : 0x" + sectionHeader.sh_offset.ToString("X16"));
//Debug.DebugMSG( " Section Size : 0x" + sectionHeader.sh_size.ToString("X16"));
}
sectionHeader.sh_link = ebr.ReadUInt32();
sectionHeader.sh_info = ebr.ReadUInt32();
//Debug.DebugMSG( " Section Link Index : 0x" + sectionHeader.sh_flags.ToString("X8"));
//Debug.DebugMSG( " Section Info Field : 0x" + sectionHeader.sh_addr.ToString("X8"));
if (ELF_FileClass.ELFCLASS_32 == hdr.e_ident.fileClass)
{
sectionHeader.sh_addralign = (UInt64) ebr.ReadUInt32();
sectionHeader.sh_entsize = (UInt64) ebr.ReadUInt32();
//Debug.DebugMSG( " Section Addr Aligmnent : 0x" + sectionHeader.sh_addralign.ToString("X8"));
//Debug.DebugMSG( " Section Entry Size : 0x" + sectionHeader.sh_entsize.ToString("X8"));
}
else
{
sectionHeader.sh_addralign = ebr.ReadUInt64();
sectionHeader.sh_entsize = ebr.ReadUInt64();
//Debug.DebugMSG( " Section Addr Aligmnent : 0x" + sectionHeader.sh_addralign.ToString("X16"));
//Debug.DebugMSG( " Section Entry Size : 0x" + sectionHeader.sh_entsize.ToString("X16"));
}
//Debug.DebugMSG("}");
return sectionHeader;
}