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Initial commit. Holy hell this code is terrible.

This commit is contained in:
Jon Michael Aanes 2015-12-16 00:05:18 +01:00
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2 changed files with 270 additions and 0 deletions

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# Infernal Interpreter & Devious Stack Painter #################################
A very simple interpreter and stack tracer for the AMD x86_64 ABI written in
Python. Does not support all commands as of yet (or anytime).

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import re
import sys
REGISTERS=["%rip","%rbp","%rsp","","%rax","%rdi","%r8","%r9"]
OPTIONS = """register_node/.style={rectangle, draw=black!30,
fill=black!5, very thick, minimum size=0.5, minimum width=20mm},
text_node/.style={}"""
class Emulator:
def __init__ (self, source_text):
self.registers = {}
for reg_name in REGISTERS:
self.registers[reg_name] = 0
self.stack = [0,1,2,3,4,5,6,7]
self.code = []
self.codep = []
self.linesExec = []
self.labels = {}
self.changes = {}
self.status = {}
self.text = ""
self.x_coord = 0
self.last_sp = 0
self.max_stack_size = 0
index = 0
for line in iter(source_text.splitlines()):
index = self.processSourceLine(line, index)
def getReg (self, reg_name):
return self.registers[reg_name]
def setRegs (self, reg_dict):
for reg_name, reg_val in reg_dict.iteritems():
self.registers[reg_name] = reg_val
def getVal (self, valText):
if valText[0] == "$":
return int(valText[1:])
elif valText[0] == "%":
return self.getReg(valText)
else:
raise "NOT A VALUE! UGHGUIHGUE!"
def compareVal (self, valT1, valT2):
val1 = self.getVal(valT2)
val2 = self.getVal(valT1)
self.status = {"g":val1>val2}
def writeRegs (self, line_nr=None):
self.text += self.draw((self.x_coord+1)*2.5-0.5, line_nr)
self.text += "\n"
self.x_coord += 1
def changedRegisters (self, *args):
for reg, val in args:
self.changes[reg] = val
def iterate (self):
old_rip = self.registers['%rip']
self.last_sp = self.registers['%rsp']
#self.linesExec.append(old_rip)
if self.registers['%rip'] >= len(self.code):
return False
instruct = self.code[self.registers['%rip']]
opcode = instruct[0]
self.changes = {}
#print(opcode, instruct)
if opcode == "push" or opcode == "pushq":
self.registers['%rsp'] = self.registers['%rsp'] + 1
self.stack[self.registers['%rsp']] = self.getReg(instruct[1])
self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']),"insert"))
self.max_stack_size = max(self.registers['%rsp'], self.max_stack_size)
elif opcode == "popq":
self.registers[instruct[1]] = self.stack[self.registers['%rsp']]
self.registers['%rsp'] = self.registers['%rsp'] - 1
self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']+1),"remove"))
elif opcode == "movq" or opcode == "mov":
self.changedRegisters((instruct[2],"change"))
self.registers[instruct[2]] = self.getVal(instruct[1])
elif opcode == "cmpq":
self.compareVal(instruct[1],instruct[2])
elif opcode == "addq":
self.changedRegisters((instruct[2],"change"))
self.registers[instruct[2]] = self.getVal(instruct[2]) + self.getVal(instruct[1])
elif opcode == "subq":
self.changedRegisters((instruct[2],"change"))
self.registers[instruct[2]] = self.getVal(instruct[2]) - self.getVal(instruct[1])
elif opcode == "jg":
if self.status["g"]:
self.registers['%rip'] = self.labels[instruct[1]]
elif opcode == "jmp":
self.registers['%rip'] = self.labels[instruct[1]]
elif opcode == "call":
self.registers['%rsp'] = self.registers['%rsp'] + 1
self.stack[self.registers['%rsp']] = self.registers['%rip']+1
self.registers['%rip'] = self.labels[instruct[1]]
self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']),"insert"))
self.max_stack_size = max(self.registers['%rsp'], self.max_stack_size)
elif opcode == "leave":
self.registers["%rsp"] = self.registers["%rbp"]
self.registers["%rbp"] = self.stack[self.registers['%rsp']]
self.registers['%rsp'] = self.registers['%rsp'] - 1
self.changedRegisters(('%rbp',"change"))
self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']+1),"remove"))
elif opcode == "ret":
self.registers['%rip'] = self.stack[self.registers['%rsp']]
self.registers['%rsp'] = self.registers['%rsp'] - 1
self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']+1),"remove"))
if self.registers['%rip'] == old_rip:
self.registers['%rip'] += 1
else:
self.changedRegisters(('%rip',"change"))
self.writeRegs(old_rip)
def processSourceLine(self, line_text, index):
tokens = re.findall(r'[\w%:$#]+', line_text)
if len(tokens) <= 0:
return index
if tokens[0][-1] == ':':
self.labels[tokens[0][:-1]] = index
tokens = tokens[1:]
for i in range(len(tokens)):
if tokens[i][0] == "#":
tokens = tokens[:i]
break
self.code.append(tokens)
self.codep.append(line_text)
return index + 1
REG_STATUS_TO_COLOR = {"insert":"green","change":"yellow","remove":"red"}
def getRegColor (self, reg_name):
if reg_name in self.changes:
return self.REG_STATUS_TO_COLOR[self.changes[reg_name]]
else:
return "black"
def getLineSignature (self, line_nr):
return [ "\\"+token if token[0]=="$" or token[0]=="%" else token for token in self.code[line_nr] ]
def draw (self, x, line_nr=None):
x = str(x)
text = ""
pos = 0
for reg_name in REGISTERS:
reg_dect = "register_node, fill=" + self.getRegColor(reg_name)+"!10"
if reg_name != "":
text += "\t\\node["+reg_dect+"]("+reg_name[1:]+") at ("+x+", "+str(pos)+"){"+str(self.registers[reg_name])+"};\n"
pos -= 0.5
pos -= 1
base_sp = max(self.last_sp,self.registers['%rsp'])
if self.last_sp - 1 == self.registers['%rsp']:
pos += 0.5
for index in range(base_sp, -1,-1):
mem_name = "m"+str(index)
reg_dect = "register_node, fill=" + self.getRegColor(mem_name)+"!10"
text += "\t\\node["+reg_dect+"]("+mem_name+") at ("+x+", "+str(pos)+"){"+str(self.stack[index])+"};\n"
pos -= 0.5
if line_nr != None:
pos = 2
signature = self.getLineSignature(line_nr)
try:
for i in range(3):
text += "\t\\node[text_node]() at ("+str(float(x)-1.25)+", "+str(pos)+"){"+signature[i]+"};\n"
pos -= 0.5
except:
pass
#for line_nr in self.linesExec:
# text += "\t\\node[text_node]() at ("+x+", "+str(pos)+"){"+self.codep[line_nr]+"};\n"
self.linesExec = []
return text
def drawNames (self, x, stack_size=8):
x = str(x)
text = ""
pos = 0
for reg_name in REGISTERS:
text += "\t\\node[text_node]("+reg_name[1:]+") at ("+x+", "+str(pos)+"){"+reg_name[1:]+"};\n"
pos -= 0.5
text += "\t\\node[text_node]() at ("+x+", "+str(pos-0.5)+"){TOS+1};\n"
text += "\t\\node[text_node]() at ("+x+", "+str(pos-1)+"){TOS};\n"
pos -= 1.5
for index in range(1,stack_size+1):
mem_name = "m"+str(index)
text += "\t\\node[text_node]() at ("+x+", "+str(pos)+"){TOS-"+str(index)+"};\n"
pos -= 0.5
return text
fib_prog = """
fib: push %rbp # push previous base pointer
movq %rsp,%rbp # setup new base pointer
if: cmpq $1, %rdi # if (a-1) > 0: goto long
jg long
quick: movq %rdi, %rax
jmp return
long: pushq %rdi # Push a onto the stack
subq $1, %rdi
call fib # Call fib(a-1)
pushq %rax # Push fib(a-1) onto the stack
subq $1, %rdi
call fib # Call fib(a-2)
popq %rdi # pop fib(a-1) into rdi
addq %rdi, %rax # rax = fib(a-1)+fib(a-2)
popq %rdi # Garentee that a lies in rdi.
return: leave # Clean up (stack pointers?)
ret # return m (rax)
"""
fib_iter_prog = """
fib: push %rbp # push previous base pointer
movq %rsp,%rbp # setup new base pointer
if: cmpq $1, %rdi # if (a-1) > 0: goto loops
jg loops
quick: movq %rdi, %rax
jmp return
loops: movq %rdi, %r8 # i (r8) = a
movq $1, %rdi # minus_one (rdi) = 1
movq $0, %rax # minus_two (rax) = 0
loopb: movq %rdi, %9 # r = minus_one
addq %rax, %rdi # minus_one += minus_two
movq %9, %rax # minus_two = r
subq $1, %r8 # i--
cmpq $0, %r8 # if a > 0
jg loopb
return: leave # Clean up
ret # return m (rax)
"""
if __name__ == "__main__":
try:
a = int(sys.argv[1])
except:
a = 2
new_em = Emulator(fib_iter_prog)
new_em.stack = ["junk...","calling eip"]
for i in range(100):
new_em.stack.append(0)
new_em.setRegs({'%rip':0,'%rbp':'old bp','%rsp':1,'%rdi':a})
print("Running for fib("+str(a)+")")
new_em.writeRegs()
while True:
if new_em.iterate() == False:
break
new_em.text += new_em.drawNames(0, new_em.max_stack_size)
print("fib("+str(a)+") = "+str(new_em.registers["%rax"]))
with open("tikz.tex","w") as f:
f.write("\\documentclass{standalone}\n\n\usepackage{tikz}\\begin{document}\n")
f.write("\\begin{tikzpicture}["+OPTIONS+"]\n")
f.write(new_em.text)
f.write("\\end{tikzpicture}\n\\end{document}")