static ElfReader.Elf64_Ehdr ReadHeader(lib.File s)
{
ElfReader.Elf64_Ehdr ret = new ElfReader.Elf64_Ehdr();
ret.e_ident_1 = ReadUInt64(s);
ret.e_ident_2 = ReadUInt64(s);
ret.e_type_machine = ReadUInt32(s);
ret.e_machine = ReadUInt32(s);
ret.e_entry = ReadUInt64(s);
ret.e_phoff = ReadUInt64(s);
ret.e_shoff = ReadUInt64(s);
ret.e_flags = ReadUInt32(s);
ret.e_ehsize_phentsize = ReadUInt32(s);
ret.e_phnum_shentsize = ReadUInt32(s);
ret.e_shnum_shstrndx = ReadUInt32(s);
/* magic should equal 0x7f, 'E', 'L', 'F'
* which is equal to 0x464c457f */
uint magic = (uint)(ret.e_ident_1 & 0xffffffff);
if (magic != 0x464c457f)
{
throw new Exception("Not a valid Elf magic number: " + magic.ToString());
}
/* EI_CLASS should equal ELFCLASS64 (= 2) */
ulong ei_class = (ret.e_ident_1 >> 32) & 0xff;
if (ei_class != 2)
{
throw new Exception("Invalid EI_CLASS: " + ei_class.ToString());
}
return(ret);
}
public static unsafe ulong LoadObject(Virtual_Regions vreg, VirtMem vmem, SymbolTable stab, lib.File s, string name, out ulong tls_size)
{
ElfReader.Elf64_Ehdr ehdr = ReadHeader(s);
/* Load up section headers */
ulong e_shentsize = ehdr.e_shentsize;
byte *shdrs = ReadStructure(s, ehdr.e_shoff, ehdr.e_shnum * e_shentsize);
/* Load up section string table */
ElfReader.Elf64_Shdr *shdr_shstr = (ElfReader.Elf64_Shdr *)(shdrs + ehdr.e_shstrndx * e_shentsize);
byte *sect_shstr = ReadStructure(s, shdr_shstr->sh_offset, shdr_shstr->sh_size);
/* Iterate through the sections marked SHF_ALLOC, allocating space as we go */
uint e_shnum = (uint)ehdr.e_shnum;
byte *sect_header = shdrs;
/* .to files are relocatable but have the entry point set anyway */
ulong text_section = 0;
ulong hdr_epoint = ehdr.e_entry;
ulong hash_section = 0;
ulong hash_len = 0;
ElfReader.Elf64_Shdr *sym_tab_hdr = null;
ElfReader.Elf64_Shdr *sym_tab_str_hdr = null;
/* Map sections to their load address */
Dictionary <uint, ulong> sect_map = new Dictionary <uint, ulong>();
ulong start = 0;
tls_size = Program.arch.tysos_tls_length;
for (uint i = 0; i < e_shnum; i++)
{
ElfReader.Elf64_Shdr *cur_shdr = (ElfReader.Elf64_Shdr *)sect_header;
// if this .symtab?
if (cur_shdr->sh_type == 0x2)
{
sym_tab_hdr = cur_shdr;
if (cur_shdr->sh_link != 0)
{
sym_tab_str_hdr = (ElfReader.Elf64_Shdr *)(shdrs + cur_shdr->sh_link * e_shentsize);
}
}
if ((cur_shdr->sh_flags & 0x2) == 0x2)
{
/* SHF_ALLOC */
if ((cur_shdr->sh_flags & (1 << 10)) != 0)
{
// TLS
tls_size += cur_shdr->sh_size;
continue;
}
// get its name
byte * name_addr = sect_shstr + cur_shdr->sh_name;
string sect_name = new string((sbyte *)name_addr);
/* Register with gc if writeable and not executable */
bool gc_data = false;
if (((cur_shdr->sh_flags & 0x1) != 0) && ((cur_shdr->sh_flags & 0x4) == 0))
{
gc_data = true;
}
// allocate space for it
ulong sect_addr = vreg.AllocRegion(cur_shdr->sh_size, 0x1000,
name + sect_name, 0,
Virtual_Regions.Region.RegionType.ModuleSection,
gc_data).start;
cur_shdr->sh_addr = sect_addr;
sect_map[i] = sect_addr;
if (sect_addr + cur_shdr->sh_size > 0x7effffffff)
{
throw new Exception("Object section allocated beyond limit of small code model");
}
// is this .text?
if (sect_name == ".text")
{
text_section = sect_addr;
}
// or .hash?
if (sect_name == ".hash")
{
hash_section = sect_addr;
hash_len = cur_shdr->sh_size;
}
// copy the section to its destination
if (cur_shdr->sh_type == 0x1)
{
/* SHT_PROGBITS */
// Convert the VirtualRegion to a managed byte array
//byte[] sect_data = libsupcs.TysosArrayType.CreateByteArray((byte*)sect_addr, (int)cur_shdr->sh_size);
byte[] sect_data = libsupcs.Array.CreateSZArray <byte>((int)cur_shdr->sh_size, (void *)sect_addr);
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: begin loading section data");
// Read the section data into it
s.Seek((long)cur_shdr->sh_offset, System.IO.SeekOrigin.Begin);
s.Read(sect_data, 0, (int)cur_shdr->sh_size);
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: end loading section data");
}
else if (cur_shdr->sh_type == 0x8)
{
/* SHT_NOBITS */
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: begin clearing blank section");
libsupcs.MemoryOperations.MemSet((void *)sect_addr, 0, (int)cur_shdr->sh_size);
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: end clearing blank section");
}
}
sect_header += e_shentsize;
}
if (hash_section != 0 && hash_len != 0 && sym_tab_hdr != null && sym_tab_str_hdr != null)
{
// Load symbol table and hash table
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: begin loading symbol table");
var sym_data = ReadStructure(s, sym_tab_hdr->sh_offset, sym_tab_hdr->sh_size);
sym_tab_hdr->sh_addr = (ulong)sym_data;
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: end loading symbol table");
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: begin loading symbol string table");
var sym_str_data = ReadStructure(s, sym_tab_str_hdr->sh_offset, sym_tab_str_hdr->sh_size);
sym_tab_str_hdr->sh_addr = (ulong)sym_str_data;
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: end loading symbol string table");
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: begin loading hash symbol section");
var ht = new ElfReader.ElfHashTable(hash_section, (ulong)sym_data, sym_tab_hdr->sh_entsize,
(ulong)sym_str_data, sect_map, (int)sym_tab_hdr->sh_info, sym_tab_hdr->sh_size);
stab.symbol_providers.Add(ht);
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: end loading hash symbol section");
}
else
{
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: begin loading symbols");
/* Iterate through defined symbols, loading them into the symbol table */
sect_header = shdrs;
for (uint i = 0; i < e_shnum; i++)
{
ElfReader.Elf64_Shdr *cur_shdr = (ElfReader.Elf64_Shdr *)sect_header;
if (cur_shdr->sh_type == 0x2)
{
/* SHT_SYMTAB */
// Load up the section data
byte *shdr_data = ReadStructure(s, cur_shdr->sh_offset, cur_shdr->sh_size);
ulong offset = cur_shdr->sh_info * cur_shdr->sh_entsize;
cur_shdr->sh_addr = (ulong)shdr_data;
while (offset < cur_shdr->sh_size)
{
ElfReader.Elf64_Sym *cur_sym = (ElfReader.Elf64_Sym *)(shdr_data + offset);
bool is_vis = false;
bool is_weak = false;
uint st_bind = (cur_sym->st_info_other_shndx >> 4) & 0xf;
if (st_bind == 1)
{
// STB_GLOBAL
is_vis = true;
}
else if (st_bind == 2)
{
// STB_WEAK
is_vis = true;
is_weak = true;
}
if (is_vis)
{
/* Get the symbol's name */
// If the appropriate string table is not loaded, then load it
ElfReader.Elf64_Shdr *strtab = (ElfReader.Elf64_Shdr *)(shdrs + cur_shdr->sh_link * e_shentsize);
if (strtab->sh_addr == 0)
{
strtab->sh_addr = (ulong)ReadStructure(s, strtab->sh_offset, strtab->sh_size);
}
// Get the name
string sym_name = new string((sbyte *)(strtab->sh_addr + cur_sym->st_name));
uint st_shndx = (cur_sym->st_info_other_shndx >> 16) & 0xffff;
if (st_shndx != 0)
{
if (is_weak == false || stab.GetAddress(sym_name) == 0)
{
ulong sym_addr = ((ElfReader.Elf64_Shdr *)(shdrs + st_shndx * e_shentsize))->sh_addr +
cur_sym->st_value;
if (sym_name == "_start")
{
start = sym_addr;
}
else
{
stab.Add(sym_name, sym_addr, cur_sym->st_size);
}
}
}
}
offset += cur_shdr->sh_entsize;
}
}
sect_header += e_shentsize;
}
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: end loading symbols");
}
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: begin fixing relocations");
/* Iterate through relocations, fixing them up as we go */
sect_header = shdrs;
for (uint i = 0; i < e_shnum; i++)
{
ElfReader.Elf64_Shdr *cur_shdr = (ElfReader.Elf64_Shdr *)sect_header;
if (cur_shdr->sh_type == 0x9)
{
throw new NotImplementedException("rel sections not supported");
}
if (cur_shdr->sh_type == 0x4)
{
/* SHT_RELA */
ElfReader.Elf64_Shdr *cur_symtab = (ElfReader.Elf64_Shdr *)(shdrs + cur_shdr->sh_link * e_shentsize);
ElfReader.Elf64_Shdr *rela_sect = (ElfReader.Elf64_Shdr *)(shdrs + cur_shdr->sh_info * e_shentsize);
/* Buffer loaded symbols */
ulong[] sym_buf = new ulong[cur_symtab->sh_size / cur_symtab->sh_entsize];
/* Load section */
byte *shdr_data = ReadStructure(s, cur_shdr->sh_offset, cur_shdr->sh_size);
cur_shdr->sh_addr = (ulong)shdr_data;
ulong offset = 0;
while (offset < cur_shdr->sh_size)
{
ElfReader.Elf64_Rela *cur_rela = (ElfReader.Elf64_Rela *)(shdr_data + offset);
ulong r_offset = rela_sect->sh_addr + cur_rela->r_offset;
ulong r_sym = cur_rela->r_info >> 32;
ulong r_type = cur_rela->r_info & 0xffffffff;
long r_addend = cur_rela->r_addend;
ElfReader.Elf64_Sym *rela_sym = (ElfReader.Elf64_Sym *)(cur_symtab->sh_addr + r_sym * cur_symtab->sh_entsize);
uint st_bind = (rela_sym->st_info_other_shndx >> 4) & 0xf;
ulong S = 0;
/* Can use direct relocation via the symbol table if:
* - not weak
* - is defined
*/
if ((st_bind == 0 || st_bind == 1) &&
rela_sym->st_shndx != 0)
{
/* STB_LOCAL symbols have not been loaded into the symbol table
* We need to use the value stored in the symbol table */
uint st_shndx = (rela_sym->st_info_other_shndx >> 16) & 0xffff;
S = ((ElfReader.Elf64_Shdr *)(shdrs + e_shentsize * st_shndx))->sh_addr +
rela_sym->st_value;
}
else
{
/* Get the symbol address from the symbol table if not already loaded */
if (sym_buf[r_sym] == 0)
{
ElfReader.Elf64_Shdr *link_sect = (ElfReader.Elf64_Shdr *)(shdrs + cur_symtab->sh_link * e_shentsize);
string sym_name = new string((sbyte *)(link_sect->sh_addr + rela_sym->st_name));
S = stab.GetAddress(sym_name);
if (S == 0)
{
throw new Exception("undefined reference to " + sym_name);
}
sym_buf[r_sym] = S;
}
else
{
S = sym_buf[r_sym];
}
}
/* Perform the relocation */
switch (r_type)
{
case 1:
// R_X86_64_64: S + A
{
ulong c = S;
if (r_addend > 0)
{
c += (ulong)r_addend;
}
else
{
c -= (ulong)(-r_addend);
}
*(ulong *)r_offset = c;
}
break;
case 2:
// R_X86_64_PC32: S + A - P
{
if (S > (ulong)long.MaxValue)
{
throw new Exception("S too large");
}
if (r_offset > (ulong)long.MaxValue)
{
throw new Exception("P too large");
}
long c = (long)S + r_addend - (long)r_offset;
if (c < int.MinValue || c > int.MaxValue)
{
throw new Exception("Relocation truncated to fit");
}
*(int *)r_offset = (int)c;
}
break;
case 10:
// R_X86_64_32: S + A
{
if (S > (ulong)long.MaxValue)
{
throw new Exception("S too large");
}
long c = (long)S + r_addend;
if (c < 0 || c > uint.MaxValue)
{
throw new Exception("Relocation truncated to fit");
}
*(uint *)r_offset = (uint)c;
}
break;
case 11:
// R_X86_64_32S: S + A
{
if (S > (ulong)long.MaxValue)
{
throw new Exception("S too large");
}
long c = (long)S + r_addend;
if (c < int.MinValue || c > int.MaxValue)
{
throw new Exception("Relocation truncated to fit");
}
*(int *)r_offset = (int)c;
}
break;
default:
throw new Exception("Unsupported relocation type: " +
r_type.ToString());
}
offset += cur_shdr->sh_entsize;
}
}
sect_header += e_shentsize;
}
System.Diagnostics.Debugger.Log(0, null, "ElfFileReader.LoadObject: end fixing relocations");
if (start == 0)
{
// assume .to file - use entry point in header
start = text_section + hdr_epoint;
}
return(start);
}
