private unsafe void WriteSectionHeader32()
{
var hdr = new Elf32_Ehdr();
ObjectFile.CopyIdentTo(new Span <byte>(hdr.e_ident, EI_NIDENT));
_encoder.Encode(out hdr.e_type, (ushort)ObjectFile.FileType);
_encoder.Encode(out hdr.e_machine, ObjectFile.Arch.Value);
_encoder.Encode(out hdr.e_version, EV_CURRENT);
_encoder.Encode(out hdr.e_entry, (uint)ObjectFile.EntryPointAddress);
_encoder.Encode(out hdr.e_ehsize, Layout.SizeOfElfHeader);
_encoder.Encode(out hdr.e_flags, (uint)ObjectFile.Flags);
// program headers
_encoder.Encode(out hdr.e_phoff, (uint)Layout.OffsetOfProgramHeaderTable);
_encoder.Encode(out hdr.e_phentsize, Layout.SizeOfProgramHeaderEntry);
_encoder.Encode(out hdr.e_phnum, (ushort)ObjectFile.Segments.Count);
// entries for sections
_encoder.Encode(out hdr.e_shoff, (uint)Layout.OffsetOfSectionHeaderTable);
_encoder.Encode(out hdr.e_shentsize, Layout.SizeOfSectionHeaderEntry);
_encoder.Encode(out hdr.e_shnum, (ushort)ObjectFile.VisibleSectionCount);
_encoder.Encode(out hdr.e_shstrndx, (ushort)(ObjectFile.SectionHeaderStringTable?.SectionIndex ?? (ushort)0));
Write(hdr);
}
protected ELF32()
{
Header = new Elf32_Ehdr();
SectionHeader = null;
SectionName = null;
NameMaxLength = 0;
}
public ELF32(string filename, bool readSectionHeaders)
: this()
{
FileStream fs = File.Open(filename, FileMode.Open);
byte[] ehdrBytes = new byte[52];
fs.Read(ehdrBytes, 0, ehdrBytes.Length);
fs.Close();
if (!(ehdrBytes[(byte)EI.MagicNumber0] == 0x7F &&
ehdrBytes[(byte)EI.MagicNumber1] == 'E' &&
ehdrBytes[(byte)EI.MagicNumber2] == 'L' &&
ehdrBytes[(byte)EI.MagicNumber3] == 'F'))
{
throw new FormatException("It is not an ELF file.");
}
if (ehdrBytes[(byte)EI.FileClass] == (byte)EC.ELF64)
{
throw new FormatException("It is an ELF64 file.");
}
else if (ehdrBytes[(byte)EI.FileClass] != (byte)EC.ELF32)
{
throw new FormatException("It is an invalid ELF class.");
}
ValueRead read = new ValueRead(ehdrBytes[(byte)EI.DataEncoding]);
Header = new Elf32_Ehdr(ehdrBytes, read);
SectionHeader = new Elf32_Shdr[Header.e_shnum];
SectionName = new string[Header.e_shnum];
if (readSectionHeaders && SectionHeader.Length != 0)
{
fs = File.Open(filename, FileMode.Open);
byte[] shdrBytes = new byte[Header.e_shnum * Header.e_shentsize];
fs.Position = Header.e_shoff;
fs.Read(shdrBytes, 0, shdrBytes.Length);
fs.Close();
for (int i = 0; i < Header.e_shnum; i++)
{
SectionHeader[i] = new Elf32_Shdr(shdrBytes, (uint)(Header.e_shentsize * i), read);
SectionName[i] = "";
}
}
}
public override ProgramImage Load(Address addrLoad)
{
int i;
m_lImageSize = RawImage.Length;
m_pImage = RawImage;
pHeader = ReadElfHeaderStart();
arch = GetProcessorArchitecture();
platform = GetPlatform();
if (pHeader.e_ident != ELF_MAGIC)
throw new BadImageFormatException("Incorrect ELF header.");
if (pHeader.e_phoff != 0)
m_pPhdrs = LoadProgramHeaders(pHeader.e_phnum, pHeader.e_phoff);
if (pHeader.e_shoff != 0)
m_pShdrs = LoadSectionHeaders(pHeader.e_shnum, pHeader.e_shoff);
// Set up section header string table pointer
if (pHeader.e_shstrndx != 0)
stringTableOffset = m_pShdrs[pHeader.e_shstrndx].sh_offset;
i = 1; // counter - # sects. Start @ 1, total m_iNumSections
// Number of sections
m_iNumSections = pHeader.e_shnum;
// Allocate room for all the Elf sections (including the silly first one)
m_pSections = new SectionInfo[m_iNumSections];
// Set up the m_sh_link and m_sh_info arrays
m_sh_link = new int[m_iNumSections];
m_sh_info = new int[m_iNumSections];
// Number of elf sections
bool bGotCode = false; // True when have seen a code sect
Address arbitaryLoadAddr = Address.Ptr32(addrLoad.Linear);
var rdr = CreateImageReader(pHeader.e_shoff);
for (i = 0; i < m_iNumSections; i++)
{
var pShdr = m_pShdrs[i];
string pName = ReadAsciiString(m_pShdrs[pHeader.e_shstrndx].sh_offset + pShdr.sh_name);
var sect = new SectionInfo();
m_pSections[i] = sect;
m_pSections[i].pSectionName = pName;
var off = pShdr.sh_offset;
if (pShdr.sh_offset != 0)
sect.uHostAddr = off;
sect.uNativeAddr = pShdr.sh_addr;
sect.uSectionSize = pShdr.sh_size;
if (sect.uNativeAddr == 0 && pName.StartsWith(".rel"))
{
int align = pShdr.sh_addralign;
if (align > 1)
{
if ((arbitaryLoadAddr.Linear % align) != 0)
arbitaryLoadAddr += (int)(align - (arbitaryLoadAddr.Linear % align));
}
sect.uNativeAddr = arbitaryLoadAddr.Offset;
arbitaryLoadAddr += sect.uSectionSize;
}
sect.uType = pShdr.sh_type;
m_sh_link[i] = pShdr.sh_link;
m_sh_info[i] = pShdr.sh_info;
sect.uSectionEntrySize = pShdr.sh_entsize;
if (sect.uNativeAddr + sect.uSectionSize > next_extern)
first_extern = next_extern = sect.uNativeAddr + sect.uSectionSize;
if ((pShdr.sh_flags & SectionFlags.SHF_WRITE) == 0)
sect.IsReadOnly = true;
// Can't use the SHF_ALLOC bit to determine bss section; the bss section has SHF_ALLOC but also SHT_NOBITS.
// (But many other sections, such as .comment, also have SHT_NOBITS). So for now, just use the name
// if ((elfRead4(&pShdr.sh_flags) & SHF_ALLOC) == 0)
if (pName == ".bss")
sect.IsBss = true;
if ((pShdr.sh_flags & SectionFlags.SHF_EXECINSTR) != 0)
{
sect.IsCode = true;
bGotCode = true; // We've got to a code section
}
// Deciding what is data and what is not is actually quite tricky but important.
// For example, it's crucial to flag the .exception_ranges section as data, otherwise there is a "hole" in the
// allocation map, that means that there is more than one "delta" from a read-only section to a page, and in the
// end using -C results in a file that looks OK but when run just says "Killed".
// So we use the Elf designations; it seems that ALLOC.!EXEC -> data
// But we don't want sections before the .text section, like .interp, .hash, etc etc. Hence bGotCode.
// NOTE: this ASSUMES that sections appear in a sensible order in the input binary file:
// junk, code, rodata, data, bss
if (bGotCode &&
(pShdr.sh_flags & (SectionFlags.SHF_EXECINSTR | SectionFlags.SHF_ALLOC)) == SectionFlags.SHF_ALLOC &&
pShdr.sh_type != SectionType.SHT_NOBITS)
sect.bData = true;
sect.Dump();
Debug.WriteLine("");
} // for each section
// assign arbitary addresses to .rel.* sections too
for (i = 0; i < m_iNumSections; i++)
{
if (m_pSections[i].uNativeAddr == 0 && m_pSections[i].pSectionName.StartsWith(".rel"))
{
m_pSections[i].uNativeAddr = arbitaryLoadAddr.Offset;
arbitaryLoadAddr += m_pSections[i].uSectionSize;
}
}
// Add symbol info. Note that some symbols will be in the main table only, and others in the dynamic table only.
// So the best idea is to add symbols for all sections of the appropriate type
for (i = 1; i < m_iNumSections; ++i)
{
var uType = m_pSections[i].uType;
if (uType == SectionType.SHT_SYMTAB || uType == SectionType.SHT_DYNSYM)
AddSyms(i);
}
// Save the relocation to symbol table info
SectionInfo pRel = GetSectionInfoByName(".rela.text");
if (pRel != null)
{
m_bAddend = true; // Remember its a relA table
m_pReloc = (Elf32_Rel*)pRel.uHostAddr; // Save pointer to reloc table
}
else
{
m_bAddend = false;
pRel = GetSectionInfoByName(".rel.text");
if (pRel != null)
{
SetRelocInfo(pRel);
m_pReloc = (Elf32_Rel*)pRel.uHostAddr; // Save pointer to reloc table
}
}
// Find the PLT limits. Required for IsDynamicLinkedProc(), e.g.
SectionInfo pPlt = GetSectionInfoByName(".plt");
if (pPlt != null)
{
m_uPltMin = pPlt.uNativeAddr;
m_uPltMax = pPlt.uNativeAddr + pPlt.uSectionSize;
}
return new ProgramImage(addrLoad, new byte[arbitaryLoadAddr - addrLoad]);
}
/// <summary>
/// Reads the ELF header.
/// </summary>
/// <returns></returns>
private Elf32_Ehdr ReadElfHeaderStart()
{
var rdr = new ImageReader(RawImage, 0);
var h = new Elf32_Ehdr();
h.e_ident = rdr.ReadBeUInt32();
h.e_class = rdr.ReadByte();
h.endianness = rdr.ReadByte();
h.version = rdr.ReadByte();
h.osAbi = rdr.ReadByte();
rdr.Seek(8); // 8 bytes of padding.
// Now that we know the endianness, read the remaining fields in endian mode.
rdr = CreateImageReader(h.endianness, rdr.Offset);
h.e_type = rdr.ReadInt16();
h.e_machine = rdr.ReadInt16();
h.e_version = rdr.ReadInt32();
h.e_entry = rdr.ReadUInt32();
h.e_phoff = rdr.ReadUInt32();
h.e_shoff = rdr.ReadUInt32();
h.e_flags = rdr.ReadInt32();
h.e_ehsize = rdr.ReadInt16();
h.e_phentsize = rdr.ReadInt16();
h.e_phnum = rdr.ReadInt16();
h.e_shentsize = rdr.ReadInt16();
h.e_shnum = rdr.ReadInt16();
h.e_shstrndx = rdr.ReadInt16();
Dump("e_type: {0}", h.e_type);
Dump("e_machine: {0}", (MachineType) h.e_machine);
Dump("e_version: {0}", h.e_version);
Dump("e_entry: {0:X}", h.e_entry);
Dump("e_phoff: {0:X}", h.e_phoff);
Dump("e_shoff: {0:X}", h.e_shoff);
Dump("e_flags: {0:X}", h.e_flags);
Dump("e_ehsize: {0}", h.e_ehsize);
Dump("e_phentsize: {0}", h.e_phentsize);
Dump("e_phnum: {0}", h.e_phnum);
Dump("e_shentsize: {0}", h.e_shentsize);
Dump("e_shnum: {0}", h.e_shnum);
Dump("e_shstrndx: {0}", h.e_shstrndx);
return h;
}
private static void GetEmbeddedModule32(ModuleReader reader, byte[] ident)
{
// Read the endiannes.
bool big = ident[(int)ElfIdent.EI_DATA] == (int)ElfData.ELFDATA2MSB;
// Read the header.
Elf32_Ehdr header = new Elf32_Ehdr();
header.Read(reader, big);
// Reject files without section names.
if (header.e_shstrndex == (int)ElfSectionNumber.SHN_UNDEF)
{
throw new ModuleException("Unsupported elfs without section names");
}
// Read the "section names" section.
reader.SetPosition((uint)(header.e_shoff + header.e_shstrndex * header.e_shentsize));
Elf32_Shdr namesHeader = new Elf32_Shdr();
namesHeader.Read(reader, big);
// Reject files without real section names.
if (namesHeader.sh_size == 0)
{
throw new ModuleException("This elf doesn't have section names.");
}
// Read the name table.
byte[] nameTable;
reader.SetPosition(namesHeader.sh_offset);
reader.Read(out nameTable, (int)namesHeader.sh_size);
// Move to the section header table.
reader.SetPosition(header.e_shoff);
// Read the section until hit '.cbm'.
Elf32_Shdr sectionHeader = new Elf32_Shdr();
bool found = false;
StringBuilder builder = new StringBuilder();
for (int i = 0; i < header.e_shnum; ++i)
{
// Read the section header.
sectionHeader.Read(reader, big);
// Check the section name.
if (sectionHeader.sh_name >= nameTable.Length)
{
throw new ModuleException("Invalid section name.");
}
// Build the section name.
builder.Length = 0;
int pos = (int)sectionHeader.sh_name;
while (nameTable[pos] != 0)
{
builder.Append((char)nameTable[pos++]);
}
string sectionName = builder.ToString();
// Compare the section name.
if (sectionName == ".cbm")
{
found = true;
break;
}
// Skip the extra data.
reader.Skip(header.e_shentsize - Elf32_Shdr.Size);
}
// Make sure the section was found.
if (!found)
{
throw new ModuleException("The elf doesn't have a chela module.");
}
// Make sure the section type is PROGBITS.
if (sectionHeader.sh_type != (int)ElfSectionType.SHT_PROGBITS)
{
throw new ModuleException("The elf section that can have the module is not supported.");
}
// Move to the section offset.
reader.SetPosition(sectionHeader.sh_offset);
}
public RPX(string filename)
{
FileStream fs = File.Open(filename, FileMode.Open);
byte[] ehdrBytes = new byte[52];
fs.Read(ehdrBytes, 0, ehdrBytes.Length);
fs.Close();
if (!(ehdrBytes[0] == 0x7F &&
ehdrBytes[1] == 'E' &&
ehdrBytes[2] == 'L' &&
ehdrBytes[3] == 'F'))
{
throw new FormatException("It is not an ELF file.");
}
if (ehdrBytes[4] != 1 ||
ehdrBytes[6] != 1)
{
throw new FormatException("It is not an ELF32 file.");
}
Header = new Elf32_Ehdr(ehdrBytes);
if (Header.e_ident[5] != 2 ||
Header.e_ident[7] != 0xCA ||
Header.e_ident[8] != 0xFE ||
Header.e_type != 0xFE01)
{
throw new FormatException("It is not an RPL/RPX file.");
}
if (Header.e_shnum == 0)
{
throw new FormatException("This RPL/RPX file has 0 sections.");
}
fs = File.Open(filename, FileMode.Open);
byte[] shdrBytes = new byte[Header.e_shnum * Header.e_shentsize];
fs.Position = Header.e_shoff;
fs.Read(shdrBytes, 0, shdrBytes.Length);
fs.Close();
SectionHeader = new Elf32_Shdr[Header.e_shnum];
int sectionCRCsIndex = 0;
for (int i = 0; i < Header.e_shnum; i++)
{
SectionHeader[i] = new Elf32_Shdr(shdrBytes, Header.e_shentsize * i);
if ((SectionHeader[i].sh_type & 0x80000003) == 0x80000003)//Section Header Type RPL CRCS
{
sectionCRCsIndex = i;
}
}
if (sectionCRCsIndex == 0)
{
throw new FormatException("Does not contain CRCs section.");
}
fs = File.Open(filename, FileMode.Open);
byte[] sectionStrBytes = new byte[SectionHeader[Header.e_shstrndx].sh_size];
fs.Position = SectionHeader[Header.e_shstrndx].sh_offset;
fs.Read(sectionStrBytes, 0, sectionStrBytes.Length);
byte[] sectionCRCsBytes = new byte[SectionHeader[sectionCRCsIndex].sh_size];
fs.Position = SectionHeader[sectionCRCsIndex].sh_offset;
fs.Read(sectionCRCsBytes, 0, sectionCRCsBytes.Length);
fs.Close();
if ((SectionHeader[Header.e_shstrndx].sh_flags & 0x08000000) == 0x08000000)//Section Header Flag RPL ZLIB
{
sectionStrBytes = Decompress(sectionStrBytes);
}
foreach (byte b in sectionStrBytes)
{
if (b > 127)
{
throw new FormatException("Section Strings are not ASCII.");
}
}
SectionName = new string[Header.e_shnum];
CRC = new uint[Header.e_shnum];
long sum = 0;
for (int i = 0; i < Header.e_shnum; i++)
{
uint stringLength = 0;
while (sectionStrBytes[SectionHeader[i].sh_name + stringLength] != 0)
{
stringLength++;
}
SectionName[i] = Encoding.ASCII.GetString(sectionStrBytes, (int)SectionHeader[i].sh_name, (int)stringLength);
CRC[i] = ReadUInt32Reverse(sectionCRCsBytes, i * 4);
sum += CRC[i];//Add all the CRCs
if (SectionHeader[i].sh_offset != 0)
{
if (SectionName[i] == ".text")
{
TextSectionIndex = i;//Always 2
}
else if (SectionName[i] == ".rodata")
{
RodataSectionIndex = i;//Always 3
}
}
}
sum -= (long)CRC[TextSectionIndex] + CRC[RodataSectionIndex] + CRC[CRC.Length - 1]; //Subtract ".text" CRC, ".rodata" CRC and "RPL Info" CRC
CRCsSum = (uint)(sum >> 4); //Discard the least significant 4 bits
FileName = filename;
}
private static void GetEmbeddedModule32(ModuleReader reader, byte[] ident)
{
// Read the endiannes.
bool big = ident[(int)ElfIdent.EI_DATA] == (int)ElfData.ELFDATA2MSB;
// Read the header.
Elf32_Ehdr header = new Elf32_Ehdr();
header.Read(reader, big);
// Reject files without section names.
if(header.e_shstrndex == (int)ElfSectionNumber.SHN_UNDEF)
throw new ModuleException("Unsupported elfs without section names");
// Read the "section names" section.
reader.SetPosition((uint) (header.e_shoff + header.e_shstrndex*header.e_shentsize));
Elf32_Shdr namesHeader = new Elf32_Shdr();
namesHeader.Read(reader, big);
// Reject files without real section names.
if(namesHeader.sh_size == 0)
throw new ModuleException("This elf doesn't have section names.");
// Read the name table.
byte[] nameTable;
reader.SetPosition(namesHeader.sh_offset);
reader.Read(out nameTable, (int)namesHeader.sh_size);
// Move to the section header table.
reader.SetPosition(header.e_shoff);
// Read the section until hit '.cbm'.
Elf32_Shdr sectionHeader = new Elf32_Shdr();
bool found = false;
StringBuilder builder = new StringBuilder();
for(int i = 0; i < header.e_shnum; ++i)
{
// Read the section header.
sectionHeader.Read(reader, big);
// Check the section name.
if(sectionHeader.sh_name >= nameTable.Length)
throw new ModuleException("Invalid section name.");
// Build the section name.
builder.Length = 0;
int pos = (int)sectionHeader.sh_name;
while(nameTable[pos] != 0)
builder.Append((char)nameTable[pos++]);
string sectionName = builder.ToString();
// Compare the section name.
if(sectionName == ".cbm")
{
found = true;
break;
}
// Skip the extra data.
reader.Skip(header.e_shentsize - Elf32_Shdr.Size);
}
// Make sure the section was found.
if(!found)
throw new ModuleException("The elf doesn't have a chela module.");
// Make sure the section type is PROGBITS.
if(sectionHeader.sh_type != (int)ElfSectionType.SHT_PROGBITS)
throw new ModuleException("The elf section that can have the module is not supported.");
// Move to the section offset.
reader.SetPosition(sectionHeader.sh_offset);
}
