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Quick&dirty verbose LuaJIT's bytecode version 1 disassembler
#!/usr/bin/env python3
import sys
import struct
import math
# Constants
# Internal (LEB128 buffer)
MAX_ULEB_SIZE = 256 # Maximum proto size here is 2^7^256
# Reference:
class ByteCode:
OP_VAR = 1
OP_STR = 2
OP_NUM = 3
OP_PRI = 4
OP_DST = 5
OP_LIT = 9 # Literal
OP_LITS = 10 # Signed literal
OP_FUNC = 11
OP_UV = 12
OP_JUMP = 13
OP_TAB = 14
OP_MNUM = 15 # Multiple nums
OP_NIL = 16 # Always nil
0x00: {"op": "ISLT", "A": OP_VAR, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {A}<{D}"},
0x01: {"op": "ISGE", "A": OP_VAR, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {A}>={D}"},
0x02: {"op": "ISLE", "A": OP_VAR, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {A}<={D}"},
0x03: {"op": "ISGT", "A": OP_VAR, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {A}>{D}"},
0x04: {"op": "ISEQV", "A": OP_VAR, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {A}={D}"},
0x05: {"op": "ISNEV", "A": OP_VAR, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {A}!={D}"},
0x06: {"op": "ISEQS", "A": OP_VAR, "B": None, "CD": OP_STR, "mode": AD_MODE, "desc": "JMP if {A}=(STR)D"}, # For STR constants?
0x07: {"op": "ISNES", "A": OP_VAR, "B": None, "CD": OP_STR, "mode": AD_MODE, "desc": "JMP if {A}!=(STR)D"},
0x08: {"op": "ISEQN", "A": OP_VAR, "B": None, "CD": OP_NUM, "mode": AD_MODE, "desc": "JMP if {A}=(NUM)D"}, # For NUM constants?
0x09: {"op": "ISNEN", "A": OP_VAR, "B": None, "CD": OP_NUM, "mode": AD_MODE, "desc": "JMP if {A}!=(NUM)D"},
0x0A: {"op": "ISEQP", "A": OP_VAR, "B": None, "CD": OP_PRI, "mode": AD_MODE, "desc": "JMP if {A}=D (primitive 0=nil,1=false,2=true)"},
0x0B: {"op": "ISNEP", "A": OP_VAR, "B": None, "CD": OP_PRI, "mode": AD_MODE, "desc": "JMP if {A}!=D (primitive 0=nil,1=false,2=true)"},
0x0C: {"op": "ISTC", "A": OP_DST, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "{A}<=copy={D} then JMP if {D}=true"},
0x0D: {"op": "ISFC", "A": OP_DST, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "{A}<=copy={D} then JMP if {D}=false"},
0x0E: {"op": "IST", "A": None, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {D}=true"},
0x0F: {"op": "ISF", "A": None, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "JMP if {D}=false"},
0x10: {"op": "MOV", "A": OP_DST, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "{A}<=copy={D}"},
0x11: {"op": "NOT", "A": OP_DST, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "{A} <= NOT {D}"},
0x12: {"op": "UNM", "A": OP_DST, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "{A} <= -{D} (unary minus)"},
0x13: {"op": "LEN", "A": OP_DST, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "{A} <= len({D})"},
0x14: {"op": "ADDVN", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= {B} + (NUM)C"},
0x15: {"op": "SUBVN", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= {B} - (NUM)C"},
0x16: {"op": "MULVN", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= {B} * (NUM)C"},
0x17: {"op": "DIVVN", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= {B} / (NUM)C"},
0x18: {"op": "MODVN", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= {B} % (NUM)C"},
0x19: {"op": "ADDNV", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= (NUM)C + {B}"},
0x1A: {"op": "SUBNV", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= (NUM)C - {B}"},
0x1B: {"op": "MULNV", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= (NUM)C * {B}"},
0x1C: {"op": "DIVNV", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= (NUM)C / {B}"},
0x1D: {"op": "MODNV", "A": OP_DST, "B": OP_VAR, "CD": OP_NUM, "mode": BC_MODE, "desc": "{A} <= (NUM)C % {B}"},
0x1E: {"op": "ADDVV", "A": OP_DST, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{A} <= {B} + {C}"},
0x1F: {"op": "SUBVV", "A": OP_DST, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{A} <= {B} - {C}"},
0x20: {"op": "MULVV", "A": OP_DST, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{A} <= {B} * {C}"},
0x21: {"op": "DIVVV", "A": OP_DST, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{A} <= {B} / {C}"},
0x22: {"op": "MODVV", "A": OP_DST, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{A} <= {B} % {C}"},
0x23: {"op": "POW", "A": OP_DST, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{A} <= {B} ^ {C}"},
0x24: {"op": "CAT", "A": OP_DST, "B": OP_RBASE, "CD": OP_RBASE, "mode": BC_MODE, "desc": "{A} <= {B} ~ {B+1} ~ ... ~ {C}"},
0x25: {"op": "KSTR", "A": OP_DST, "B": None, "CD": OP_STR, "mode": AD_MODE, "desc": "{A} <= (STR)D"},
0x26: {"op": "KCDATA", "A": OP_DST, "B": None, "CD": OP_CDATA, "mode": AD_MODE, "desc": "{A} <= (CDATA)D"},
0x27: {"op": "KSHORT", "A": OP_DST, "B": None, "CD": OP_LITS, "mode": AD_MODE, "desc": "{A} <= D (16-bit signed int)"},
0x28: {"op": "KNUM", "A": OP_DST, "B": None, "CD": OP_NUM, "mode": AD_MODE, "desc": "{A} <= (NUM)D"},
0x29: {"op": "KPRI", "A": OP_DST, "B": None, "CD": OP_PRI, "mode": AD_MODE, "desc": "{A} <= D (primitive 0=nil,1=false,2=true)"},
0x2A: {"op": "KNIL", "A": OP_BASE, "B": None, "CD": OP_BASE, "mode": AD_MODE, "desc": "{A} <= nil, {A+1} <= nil, ..., {D} <= nil"},
0x2B: {"op": "UGET", "A": OP_DST, "B": None, "CD": OP_UV, "mode": AD_MODE, "desc": "{A} <= uv(D)"},
0x2C: {"op": "USETV", "A": OP_UV, "B": None, "CD": OP_VAR, "mode": AD_MODE, "desc": "uv(A) <= {D}"},
0x2D: {"op": "USETS", "A": OP_UV, "B": None, "CD": OP_STR, "mode": AD_MODE, "desc": "uv(A) <= (STR)D"},
0x2E: {"op": "USETN", "A": OP_UV, "B": None, "CD": OP_NUM, "mode": AD_MODE, "desc": "uv(A) <= (NUM)D"},
0x2F: {"op": "USETP", "A": OP_UV, "B": None, "CD": OP_PRI, "mode": AD_MODE, "desc": "uv(A) <= D (primitive 0=nil,1=false,2=true)"},
0x30: {"op": "UCLO", "A": OP_RBASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Closes uv for slots >= A and JMP => D"},
0x31: {"op": "FNEW", "A": OP_DST, "B": None, "CD": OP_FUNC, "mode": AD_MODE, "desc": "{A} <= closure(proto(D))"},
0x32: {"op": "TNEW", "A": OP_DST, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "{A}<=[new_tab[D&0x07FF] new_hash[(D&0xF800)>>11]]"},
0x33: {"op": "TDUP", "A": OP_DST, "B": None, "CD": OP_TAB, "mode": AD_MODE, "desc": "{A} <= (TAB)D"},
0x34: {"op": "GGET", "A": OP_DST, "B": None, "CD": OP_STR, "mode": AD_MODE, "desc": "{A} <= _G[(STR)D] (see getfenv(1))"},
0x35: {"op": "GSET", "A": OP_VAR, "B": None, "CD": OP_STR, "mode": AD_MODE, "desc": "_G[(STR)D] <= {A} (see getfenv(1))"},
0x36: {"op": "TGETV", "A": OP_DST, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{A} <= {B}[{C}]"},
0x37: {"op": "TGETS", "A": OP_DST, "B": OP_VAR, "CD": OP_STR, "mode": BC_MODE, "desc": "{A} <= {B}[(STR)C]"},
0x38: {"op": "TGETB", "A": OP_DST, "B": OP_VAR, "CD": OP_LIT, "mode": BC_MODE, "desc": "{A} <= {B}[C]"},
0x39: {"op": "TSETV", "A": OP_VAR, "B": OP_VAR, "CD": OP_VAR, "mode": BC_MODE, "desc": "{B}[{C}] <= {A}"},
0x3A: {"op": "TSETS", "A": OP_VAR, "B": OP_VAR, "CD": OP_STR, "mode": BC_MODE, "desc": "{B}[(STR)C] <= {A}"},
0x3B: {"op": "TSETB", "A": OP_VAR, "B": OP_VAR, "CD": OP_LIT, "mode": BC_MODE, "desc": "{B}[C] <= {A}"},
0x3C: {"op": "TSETM", "A": OP_BASE, "B": None, "CD": OP_MNUM, "mode": AD_MODE, "desc": "{A-1}[(NUM)D],{A-1}[D+1],...<= {A}, {A+1}, ..."},
0x3D: {"op": "CALLM", "A": OP_BASE, "B": OP_LIT, "CD": OP_LIT, "mode": BC_MODE, "desc": "{A},...,{A+B-2}<={A}({A+1},...,{A+C+MULTRES})"},
0x3E: {"op": "CALL", "A": OP_BASE, "B": OP_LIT, "CD": OP_LIT, "mode": BC_MODE, "desc": "{A},...,{A+B-2} <= {A}({A+1},...,{A+C-1})"},
0x3F: {"op": "CALLMT", "A": OP_BASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "Tailcall: {A}({A+1},...,{A+D+MULTRES})"},
0x40: {"op": "CALLT", "A": OP_BASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "Tailcall: {A}({A+1},...,{A+D-1})"},
0x41: {"op": "ITERC", "A": OP_BASE, "B": OP_LIT, "CD": OP_LIT, "mode": BC_MODE, "desc": "Iterator: {A},{A+1},{A+2}<={A-3},{A-2},{A-1};{A},...,{A+B-2} <= {A}({A+1},{A+2})"},
0x42: {"op": "ITERN", "A": OP_BASE, "B": OP_LIT, "CD": OP_LIT, "mode": BC_MODE, "desc": "Specialized ITERC, if iterator function {A-3} is next()"},
0x43: {"op": "VARG", "A": OP_BASE, "B": OP_LIT, "CD": OP_LIT, "mode": BC_MODE, "desc": "Vararg: {A},...{A+B-2} <= ..."},
0x44: {"op": "ISNEXT", "A": OP_BASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Verify ITERN specialization and jump"},
0x45: {"op": "RETM", "A": OP_BASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "return {A},...,{A+D+MULTRES-1}"},
0x46: {"op": "RET", "A": OP_RBASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "return {A},...,{A+D-2}"},
0x47: {"op": "RET0", "A": OP_RBASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "return"},
0x48: {"op": "RET1", "A": OP_RBASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "return {A}"},
0x49: {"op": "FORI", "A": OP_BASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Numeric for loop init"},
0x4A: {"op": "JFORI", "A": OP_BASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Numeric for loop init JIT-compiled"},
0x4B: {"op": "FORL", "A": OP_BASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Numeric for loop"},
0x4C: {"op": "IFORL", "A": OP_BASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Numeric for loop force interpreter"},
0x4D: {"op": "JFORL", "A": OP_BASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "Numeric for loop JIT-compiled"},
0x4E: {"op": "ITERL", "A": OP_BASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Iterator for loop"},
0x4F: {"op": "IITERL", "A": OP_BASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Iterator for loop force interpreter"},
0x50: {"op": "JITERL", "A": OP_BASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "Iterator for loop JIT-compiled"},
0x51: {"op": "LOOP", "A": OP_RBASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Generic loop"},
0x52: {"op": "ILOOP", "A": OP_RBASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Generic loop, force interpreter"},
0x53: {"op": "JLOOP", "A": OP_RBASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "Generic loop,JIT-Compiled"},
0x54: {"op": "JMP", "A": OP_RBASE, "B": None, "CD": OP_JUMP, "mode": AD_MODE, "desc": "Jump"},
0x55: {"op": "FUNCF", "A": OP_RBASE, "B": None, "CD": OP_NIL, "mode": AD_MODE, "desc": "Fixed-arg Lua function"},
0x56: {"op": "IFUNCF", "A": OP_RBASE, "B": None, "CD": OP_NIL, "mode": AD_MODE, "desc": "Fixed-arg Lua function, force interpreter"},
0x57: {"op": "JFUNCF", "A": OP_RBASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "Fixed-arg Lua function JIT-Compiled"},
0x58: {"op": "FUNCV", "A": OP_RBASE, "B": None, "CD": OP_NIL, "mode": AD_MODE, "desc": "Vararg Lua function"},
0x59: {"op": "IFUNCV", "A": OP_RBASE, "B": None, "CD": OP_NIL, "mode": AD_MODE, "desc": "Vararg Lua function, force interpreter"},
0x5A: {"op": "JFUNCV", "A": OP_RBASE, "B": None, "CD": OP_LIT, "mode": AD_MODE, "desc": "Vararg Lua function, JIT-compiled"},
0x5B: {"op": "FUNCC", "A": OP_RBASE, "B": None, "CD": OP_NIL, "mode": AD_MODE, "desc": "Pseudo-header for C functions"},
0x5C: {"op": "FUNCCW", "A": OP_RBASE, "B": None, "CD": OP_NIL, "mode": AD_MODE, "desc": "Pseudo-header for wrapped C functions"},
0x5D: {"op": "FUNC", "A": OP_RBASE, "B": None, "CD": OP_NIL, "mode": AD_MODE, "desc": "Pseudo-header for fast functions"},
def listBC(bytecode, kgc=None, knum=None, upvalues=None):
outStr = "N\tOP\tA\tB/D\tC\tComment\n"
i = 1
for ins in bytecode:
if len(ins) != 4:
# An instruction is always a 32-bit word
# If the OPCODE >= 5D, we have a fast function pseudo-header
op = {"op": "FUNC", "A": ByteCode.OP_RBASE, "B": None, "CD": ByteCode.OP_NIL, "mode": ByteCode.AD_MODE, "desc": "Pseudo-header for fast functions"}
if ins[0] in ByteCode.OPCODE_TABLE.keys():
op = ByteCode.OPCODE_TABLE[ins[0]]
outStr += "%03d\t%s\t" % (i,op['op'])
outStr += "%d\t" % ins[1]
if op['mode'] == ByteCode.BC_MODE:
outStr += "%d\t%d\t; %s\n" % (ins[3], ins[2], op["desc"])
outStr += "0x%02x%02x\t\t; %s\n" % (ins[3], ins[2], op['desc'])
# FIXME ugly part
if op["A"] == ByteCode.OP_PRI:
pri = "true"
if ins[1] == 0:
pri = "nil"
elif ins[1] == 1:
pri = "false"
outStr += "\t(PRI)A= %s\n" % pri
if op["B"] == ByteCode.OP_PRI:
pri = "true"
if ins[3] == 0:
pri = "nil"
elif ins[3] == 1:
pri = "false"
outStr += "\t(PRI)B= %s\n" % pri
if op["CD"] == ByteCode.OP_PRI:
j = 2
pri = "true"
if ins[j] == 0:
pri = "nil"
elif ins[j] == 1:
pri = "false"
outStr += "\t(PRI)C/D= %s\n" % pri
if op["CD"] == ByteCode.OP_JUMP:
outStr += "\tJMP => %d\n" % (i + 1 + struct.unpack("H", bytes([ins[2],ins[3]]))[0] - 0x8000)
if kgc is not None:
# TODO cover other kgc types (tab)
if op["A"] == ByteCode.OP_STR:
outStr += "\t(STR)A= \"%s\"\n" % kgc[ins[1]].getValue()
if op['B'] == ByteCode.OP_STR:
outStr += "\t(STR)B= \"%s\"\n" % kgc[ins[3]].getValue()
if op['CD'] == ByteCode.OP_STR and op["mode"] == ByteCode.BC_MODE:
outStr += "\t(STR)C= \"%s\"\n" % kgc[ins[2]].getValue()
elif op['CD'] == ByteCode.OP_STR:
outStr += "\t(STR)D= \"%s\"\n" % kgc[struct.unpack("<H", ins[2:4])[0]].getValue()
if knum is not None:
if op["A"] == ByteCode.OP_NUM:
if type(knum[ins[1]]) == int:
outStr += "\t(NUM)A= %d\n" % knum[ins[1]]
elif type(knum[ins[1]]) == float:
outStr += "\t(NUM)A= %f\n" % knum[ins[1]]
if op['B'] == ByteCode.OP_NUM:
if type(knum[ins[3]]) == int:
outStr += "\t(NUM)B= %d\n" % knum[ins[3]]
elif type(knum[ins[3]]) == float:
outStr += "\t(NUM)B= %f\n" % knum[ins[3]]
if op['CD'] == ByteCode.OP_NUM and op["mode"] == ByteCode.BC_MODE:
if type(knum[ins[2]]) == int:
outStr += "\t(NUM)C= %d\n" % knum[ins[2]]
elif type(knum[ins[2]]) == float:
outStr += "\t(NUM)C= %f\n" % knum[ins[2]]
elif op['CD'] == ByteCode.OP_NUM:
val = knum[struct.unpack("<H", ins[2:4])[0]]
if type(val) == int:
outStr += "\t(NUM)D= %d\n" % val
elif type(val) == float:
outStr += "\t(NUM)D= %f\n" % val
i += 1
return outStr
def read_uleb128(buff):
# Adapted from l. 136
result = buff[0]
i = 1
if result >= 0x80:
shift = 0
result &= 0x7F
while True:
shift += 7
result |= ((buff[i] & 0x7F) << shift)
i += 1
if buff[i-1] < 0x80:
return [result, i]
def read_uleb128_33(buff):
# Adapted from l. 154
# FIXME not tested yet
result = buff[0] >> 1
i = 1
if result >= 0x40:
shift = -1
result &= 0x3F
while True:
ch = buff[i]
shift += 7
result |= (ch & 0x7F) << shift
i += 1
if buff[i-1] < 0x80:
return [result, i]
return [result, i]
def hexd(string):
Helper function to hexdump bytecode
out_val = ''
for ch in string:
out_val += hex(ch) + " "
return out_val
class Kgc:
Class to contain KGC values (a type and a value)
# From:
# KGC types
KGC_I64 = 2
KGC_U64 = 3
# ktabk types
def __init__(self, type_kgc, value):
self.type_kgc = type_kgc
self.value = value
def getType(self):
return self.type_kgc
def getKtabTypeAsStr(ktype):
if ktype >= Kgc.KTAB_STR:
return "KTAB_STR"
if ktype == Kgc.KTAB_NIL:
return "KTAB_NIL"
if ktype == Kgc.KTAB_FALSE:
return "KTAB_FALSE"
if ktype == Kgc.KTAB_TRUE:
return "KTAB_TRUE"
if ktype == Kgc.KTAB_NUM:
return "KTAB_NUM"
if ktype == Kgc.KTAB_INT:
return "KTAB_INT"
return "Unknown"
def getValue(self):
return self.value
def toStr(self):
outStr = "Type: "
if self.type_kgc == Kgc.KGC_CHILD:
outStr += "KGC_CHILD\t"
elif self.type_kgc == Kgc.KGC_TAB:
outStr += "KGC_TAB\t"
outStr += "karray length: %d\t khash length: %d\n" % (len(self.value["karray"]), len(self.value["khash"]))
for el in self.value["karray"]:
outStr += "\t\ttype: %s\tvalue: " % Kgc.getKtabTypeAsStr(el["type"])
if el["value"] is None:
outStr += "None\n"
elif el["value"] is False:
outStr += "false\n"
elif el["type"] == Kgc.KTAB_TRUE:
outStr += "true\n"
elif el["type"] == Kgc.KTAB_NUM:
outStr += "lo: %d, hi: %d" % (el["value"][0],el["value"][1])
elif el["type"] >= Kgc.KTAB_STR:
outStr += "%s\n" % el["value"].decode('ascii')
elif el["type"] == Kgc.KTAB_INT:
outStr += "%d\n" % el["value"]
outStr += "Should not happen DUH!\n"
# TODO ugly
for el in self.value["khash"]:
outStr += "\t\tkey:" + el["key"].decode('ascii') + "\ttype: %s\tvalue: " % Kgc.getKtabTypeAsStr(el["type"])
if el["value"] is None:
outStr += "None\n"
elif el["value"] is False:
outStr += "false\n"
elif el["type"] == Kgc.KTAB_TRUE:
outStr += "true\n"
elif el["type"] == Kgc.KTAB_NUM:
outStr += "%f" % el['value']
elif el["type"] >= Kgc.KTAB_STR:
outStr += "%s\n" % el["value"].decode('ascii')
elif el["type"] == Kgc.KTAB_INT:
outStr += "%d\n" % el["value"]
outStr += "Should not happen DUH!\n"
elif self.type_kgc >= Kgc.KGC_STR:
outStr += "KGC_STR\t"
outStr += self.value.decode('ascii')
else: # TODO add the other types here if relevant
outStr += "%d Not supported yet\n" % self.type_kgc
return outStr
class GCProto:
# From:
# GCProto flags
PROTO_CHILD = 0x01 # Indicates if there are child prototypes
PROTO_VARARG = 0x02 # Vararg function
PROTO_FFI = 0x04 # Uses BC_KCDATA for FFI datatypes
PROTO_NOJIT = 0x08 # JIT disabled for this function
PROTO_ILOOP = 0x10 # Patched bytecode with ILOOP, etc...
def __init__(self, f_strip = True):
self.flags = 0x00 # Proto's flags
self.numparams = 0 # Number of parameters
self.framesize = 0 # Fixed frame size
self.numuv = 0 # Number of upvalues
self.numkgc = 0 # Number of collectable constants
self.numkn = 0 # Number of lua_number constants
self.numbc = 0 # Number of bytecode instructions
self.debuglen = 0 # Length of the debugpart in the header
self.debug_firstline = None # First line of the function definition
self.debug_numline = None # Number of lines for the function definition
self.bcins = [] # Bytecode instructions?
self.uvdata = [] # upvalue list
self.kgc = [] # Split constant array
self.knum = [] # Lua number constants
self.debug = [] # Debug bytes
self.f_strip = f_strip # If the GCDump Strip flag is set (debug)
def parseKtabk(self, buff):
Parses a ktabk entry
tot_bytes_read = 0
uleb_buff_size = min([len(buff), MAX_ULEB_SIZE])
ktabktype, bytes_read = read_uleb128(buff[:uleb_buff_size])
tot_bytes_read += bytes_read
return_value = None
if ktabktype >= Kgc.KTAB_STR:
str_len = ktabktype - Kgc.KTAB_STR
ktabk_string = buff[tot_bytes_read:tot_bytes_read+str_len]
tot_bytes_read += str_len
return_value = ktabk_string
elif ktabktype == Kgc.KTAB_INT:
uleb_buff_size = min([len(buff[tot_bytes_read:]), MAX_ULEB_SIZE])
return_value, bytes_read = read_uleb128(buff[tot_bytes_read:tot_bytes_read+uleb_buff_size])
tot_bytes_read += bytes_read
elif ktabktype == Kgc.KTAB_NUM:
uleb_buff_size = min([len(buff[tot_bytes_read:]), MAX_ULEB_SIZE])
lo, bytes_read = read_uleb128(buff[tot_bytes_read:tot_bytes_read+uleb_buff_size])
tot_bytes_read += bytes_read
uleb_buff_size = min([len(buff[tot_bytes_read:]), MAX_ULEB_SIZE])
hi, bytes_read = read_uleb128(buff[tot_bytes_read:tot_bytes_read+uleb_buff_size])
tot_bytes_read += bytes_read
return_value = [lo, hi]
else: # Boolean or nil
if ktabktype == Kgc.KTAB_TRUE:
return_value = True
elif ktabktype == Kgc.KTAB_FALSE:
return_value = False
return_value = None
return [ktabktype, return_value, tot_bytes_read]
def parseFromBuff(self, buff):
Parses buffer to identify proto header and body
# A proto header has at least 7 bytes, so there is an error if it is less
if len(buff) < 7:
# The first header elements are quite simple
self.flags = buff[0]
self.numparams = buff[1]
self.framesize = buff[2]
self.numuv = buff[3]
# LEB128 needs some precautions (in case they are multibyte)
uleb_buff_size = min([len(buff)-4, MAX_ULEB_SIZE])
self.numkgc, bytes_read = read_uleb128(buff[4:4+uleb_buff_size])
off = 4 + bytes_read
uleb_buff_size = min([len(buff)-off, MAX_ULEB_SIZE])
self.numkn, bytes_read = read_uleb128(buff[off:off+uleb_buff_size])
off += bytes_read
uleb_buff_size = min([len(buff)-off, MAX_ULEB_SIZE])
self.numbc, bytes_read = read_uleb128(buff[off:off+uleb_buff_size])
# See line 357
# The following code is about debug bytes retrieval
# I don't interpret them at the moment, this is just to let the pointer increment and skip this part is it exists
if not self.f_strip:
off += bytes_read
uleb_buff_size = min([len(buff)-off, MAX_ULEB_SIZE])
self.debuglen, bytes_read = read_uleb128(buff[off:uleb_buff_size])
if self.debuglen > 0:
off += bytes_read
uleb_buff_size = min([len(buff)-off,MAX_ULEB_SIZE])
self.debug_firstline, bytes_read = read_uleb128(buff[off:uleb_buff_size])
off += bytes_read
uleb_buff_size = min([len(buff)-off, MAX_ULEB_SIZE])
self.debug_numline, bytes_read = read_uleb128(buff[off:uleb_buff_size])
# This is the end of the header
# The first thing after is the bytecode listing
# Each instruction has a size of a 32-bit word
# We don't disassemble the bytecode yet, maybe a bit later
off += bytes_read
base = off
while off < base + self.numbc * 4:
off += 4
# End of the bytecode listing
# Listing of Upvalue refs (see lua doc about that)
# Each upvalue is a 16-bit word
base = off
while off < base + self.numuv*2:
self.uvdata.append(struct.unpack("<H", buff[off:off+2])[0]) # TODO verify endianness
off += 2
base = off
# End of the upvalue listing
# Now we have to handle constants
# We will create KGCs based on their type here
# First, we get kgc's type
# Check at line 244
for i in range(0, self.numkgc):
if len(buff[base:]) == 0:
uleb_buff_size = min([len(buff[base:]), MAX_ULEB_SIZE])
kgc_type, bytes_read = read_uleb128(buff[base:base+uleb_buff_size])
base += bytes_read
kgc_var = None
# If the type is >= than KGC_STR, then it is a string and its length is the type minus KGC_STR
if kgc_type >= Kgc.KGC_STR:
kgc_len = kgc_type - Kgc.KGC_STR
kgc_string = buff[base:base+kgc_len]
base += kgc_len
kgc_var = Kgc(kgc_type, kgc_string)
elif kgc_type == Kgc.KGC_TAB:
# Here we read a karray
uleb_buff_size = min([len(buff[base:]), MAX_ULEB_SIZE])
narray, bytes_read = read_uleb128(buff[base:base+uleb_buff_size])
base += bytes_read
uleb_buff_size = min([len(buff[base:]), MAX_ULEB_SIZE])
nhash, bytes_read = read_uleb128(buff[base:base+uleb_buff_size])
base += bytes_read
ktab = {}
karray = []
khash = []
for i in range(0, narray):
val_type, value, bytes_read = self.parseKtabk(buff[base:])
karray.append({"type": val_type, "value": value})
base += bytes_read
for i in range(0, nhash):
key_type, key, bytes_read = self.parseKtabk(buff[base:])
base += bytes_read
# No null index. This should not happen on a well-formed BCDump
if key_type == Kgc.KTAB_NIL or key_type == Kgc.KTAB_FALSE or key_type == Kgc.KTAB_TRUE:
key = "null_key"
val_type, value, bytes_read = self.parseKtabk(buff[base:])
base += bytes_read
khash.append({"type": val_type, "key": key, "value": value})
ktab = {"karray": karray, "khash": khash}
kgc_var = Kgc(kgc_type, ktab)
elif kgc_type != Kgc.KGC_CHILD:
# TODO As this is only possible if FFI is activated, I didn't implemented it yet
print("Warn! Something is not implemented here, could crash or yield incorrect results")
kgc_var = Kgc(kgc_type, "")
# Here we assume that kgc_type == Kgc.KGC_CHILD
# TODO I'm not sure, but it seems this type is dedicated to embed protos as constants
#print("Warn! Something is not implemented here, could crash or yield incorrect results")
kgc_var = Kgc(kgc_type, "")
# NOTE the 2 last cases will break the lexer if they happen, in case of crash, add the right parsing. My guess is that these are not common
# Pfiou! End of kgc parsing
# Let's do knum parsing
for i in range(0, self.numkn):
isnum = buff[base] & 1
lo, bytes_read = read_uleb128_33(buff[base:])
base += bytes_read
if isnum != 0:
hi, bytes_read = read_uleb128(buff[base:])
base += bytes_read
self.knum.append(struct.unpack('d', struct.pack('I',lo)+struct.pack('I',hi))[0])
self.kgc = list(reversed(self.kgc))
self.knum = list(reversed(self.knum))
def toString(self):
Dumps a proto object to string
outStr = "---- Proto ----\n"
outStr += "Flags: "
if self.flags & GCProto.PROTO_CHILD != 0:
outStr += "PROTO_CHILD "
if self.flags & GCProto.PROTO_VARARG != 0:
outStr += "PROTO_VARARG "
if self.flags & GCProto.PROTO_FFI != 0:
outStr += "PROTO_FFI "
if self.flags & GCProto.PROTO_NOJIT != 0:
outStr += "PROTO_NOJIT "
if self.flags & GCProto.PROTO_ILOOP != 0:
outStr += "PROTO_ILOOP "
outStr += "\n"
outStr += "Number of parameters: %d\n" % self.numparams
outStr += "Frame size: %d\n" % self.framesize
outStr += "Number of upvalues: %d\n" % self.numuv
outStr += "Number of collectable constants: %d\n" % self.numkgc
outStr += "Number of numeric constants: %d\n" % self.numkn
outStr += "Number of bytecode instructions: %d\n" % self.numbc
if self.debuglen > 0:
outStr += "Debug firstline-numline: %d-%d\n" % (self.debug_firstline, self.debug.numline)
if self.numbc > 0:
outStr += "Bytecode dump: \n"
outStr += ByteCode.listBC(self.bcins, self.kgc, self.knum)
#for i in range(0, self.numbc):
# outStr += ("%03d\t" % (i+1)) + hexd(self.bcins[i]) + "\n"
if self.numuv > 0:
outStr += "UVData dump: \n"
for i in range(0, self.numuv):
outStr += ("%03d\t" % (i+1)) + "0x %04x" % self.uvdata[i] + "\n"
outStr += "KGC Vars: \n"
for i in range(0, len(self.kgc)):
if self.kgc[i] is not None:
outStr += "%03d\t%s\n" % (i, self.kgc[i].toStr())
if self.numkn > 0:
outStr += "KNum Vars: \n"
for i in range(0, self.numkn):
if type(self.knum[i]) is float :
outStr += "%03d\t%f\n" % (i, self.knum[i])
elif type(self.knum[i]) is int:
outStr += "%03d\t%d\n" % (i, self.knum[i])
return outStr
class BCDump:
Represents the full bytecode dump (whole file)
# From:
# Doc:
# Header Flags
F_BE = 0x01
F_STRIP = 0x02 # Debug flag (roughly)
F_FFI = 0x04 # Does the dump depend on FFI?
def __init__(self):
# Creates a new empty BCDump object
self.protos = [] # List of the protos (function blocks)
self.version = None # Bytecode version (1 in most of the cases)
self.flags = 0x00 # Dump flags = None # Dump name
self.cleanEnd = False # Did the lexer do the job properly?
self.f_strip = True # Shortcut to self.flags & F_STRIP
def getVersion(self):
Returns the version number
return self.version
def getFlags(self):
Returns the flags
return self.flags
def flagsToStr(self):
Returns the flags as string listing for human reading
str_flag = ""
if self.flags & BCDump.F_BE != 0:
str_flag += 'F_BE '
if self.flags & BCDump.F_STRIP != 0:
str_flag += 'F_STRIP '
if self.flags & BCDump.F_FFI != 0:
str_flag += 'F_FFI '
return str_flag
def getName(self):
Returns th dump's name
def getProtos(self):
Returns the list of protos
return self.protos
def isEndClean(self):
Returns if the lexer ended successfully
return self.cleanEnd
def parseFile(self, bin_file):
Parses an input file as a BC Dump
# First check the magic bytes and return if wrong format
first_bytes =
if first_bytes != b'\x1bLJ':
print("Not a luaJIT file (wrong magic bytes)!")
# Get basic information from dump header
self.version = struct.unpack("B",[0]
self.flags = struct.unpack("B",[0]
buff = b''
nameLength = 0
# If debug symbols are in file, we have a name
if self.flags & BCDump.F_STRIP == 0:
self.f_strip = False
buff =
tmp = read_uleb128(buff)
nameLength = tmp[0]
i = tmp[1]
name = ''
if nameLength >= len(buff[i:]):
name = buff[i:] +[i:]))
buff = b'' = name.decode('ascii') # Which encoding is really used? This is not specified
else: = buff[i:nameLength+1].decode('ascii') # Same as above
buff = buff[nameLength+1:]
# We finished reading the header, let's get all the protos
still_has_proto = True
proto_number = 0
buff =
while still_has_proto:
if len(buff) < MAX_ULEB_SIZE:
buff = buff +
# The first part of a proto is its length
tmp, bytes_read = read_uleb128(buff)
# If we reach the end of the file before being able to retrieve the announced number of protos
if len(buff) == 0 or tmp == 0:
still_has_proto = False
proto_size = tmp
bytes_offset = bytes_read
proto_number += 1
# Retrieval of proto bytes
if proto_size > len(buff[bytes_offset:]):
proto = buff[bytes_offset:] +[bytes_offset:]))
buff = b''
proto = buff[bytes_offset:bytes_offset+proto_size]
buff = buff[proto_size+bytes_offset:]
# Initialize the proto object
obj_proto = GCProto(self.f_strip)
# If we only have a null byte left, the job is finished
if buff == b'\x00':
self.cleanEnd = True
if len(sys.argv) != 2:
print("Usage: %s <lua_file>" % sys.argv[0])
bin_file = open(sys.argv[1], "rb")
bcdump = BCDump()
if bcdump.getVersion() is None:
print("Bytecode version: %d" % bcdump.getVersion())
print("Flags: %s" % bcdump.flagsToStr())
if bcdump.getName() is not None:
print("File has a name: %s" % bcdump.getName())
i = 1
for proto in bcdump.getProtos():
print("------------ Proto %d -------------" % i)
i += 1
if bcdump.isEndClean():
print("Clean end")

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@anzteam anzteam commented Mar 1, 2021

Could you provide me your email to discuss about LuaJIT Decompile & Compile?

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