Instruction:
Can you tell what is the following Python 3 function doing
def concretize(self, symbolic, policy, maxcount=7):
        assert self.constraints == self.platform.constraints
        symbolic = self.migrate_expression(symbolic)

        vals = []
        if policy == 'MINMAX':
            vals = self._solver.minmax(self._constraints, symbolic)
        elif policy == 'MAX':
            vals = self._solver.max(self._constraints, symbolic)
        elif policy == 'MIN':
            vals = self._solver.min(self._constraints, symbolic)
        elif policy == 'SAMPLED':
            m, M = self._solver.minmax(self._constraints, symbolic)
            vals += [m, M]
            if M - m > 3:
                if self._solver.can_be_true(self._constraints, symbolic == (m + M) // 2):
                    vals.append((m + M) // 2)
            if M - m > 100:
                for i in (0, 1, 2, 5, 32, 64, 128, 320):
                    if self._solver.can_be_true(self._constraints, symbolic == m + i):
                        vals.append(m + i)
                    if maxcount <= len(vals):
                        break
            if M - m > 1000 and maxcount > len(vals):
                vals += self._solver.get_all_values(self._constraints, symbolic,
                                                    maxcnt=maxcount - len(vals), silent=True)
        elif policy == 'ONE':
            vals = [self._solver.get_value(self._constraints, symbolic)]
        else:
            assert policy == 'ALL'
            vals = solver.get_all_values(self._constraints, symbolic, maxcnt=maxcount, silent=True)

        return tuple(set(vals))

Response: This method concretizes a set of solutions for a given symbolic.


Instruction:
Can you create a Python 3 function that
solves a symbolic value into one solution.

Response:
def solve_one(self, expr, constrain=False):
        """
        Concretize a symbolic :class:`~manticore.core.smtlib.expression.Expression` into
        one solution.

        :param manticore.core.smtlib.Expression expr: Symbolic value to concretize
        :param bool constrain: If True, constrain expr to concretized value
        :return: Concrete value
        :rtype: int
        """
        expr = self.migrate_expression(expr)
        value = self._solver.get_value(self._constraints, expr)
        if constrain:
            self.constrain(expr == value)
        #Include forgiveness here
        if isinstance(value, bytearray):
            value = bytes(value)
        return value


Instruction:
Create a Python 3 function for
solving a symbolic value into a list of n possible values.

Response:
def solve_n(self, expr, nsolves):
        """
        Concretize a symbolic :class:`~manticore.core.smtlib.expression.Expression` into
        `nsolves` solutions.

        :param manticore.core.smtlib.Expression expr: Symbolic value to concretize
        :return: Concrete value
        :rtype: list[int]
        """
        expr = self.migrate_expression(expr)
        return self._solver.get_all_values(self._constraints, expr, nsolves, silent=True)


Instruction:
Can you tell what is the following Python 3 function doing
def solve_max(self, expr):
        if isinstance(expr, int):
            return expr
        expr = self.migrate_expression(expr)
        return self._solver.max(self._constraints, expr)

Response:
Solves a symbolic value into
        its maximum solution.


Instruction:
Implement a function in Python 3 to
solve a symbolic value into its minimum solution.

Response:
def solve_min(self, expr):
        """
        Solves a symbolic :class:`~manticore.core.smtlib.expression.Expression` into
        its minimum solution

        :param manticore.core.smtlib.Expression expr: Symbolic value to solve
        :return: Concrete value
        :rtype: list[int]
        """
        if isinstance(expr, int):
            return expr
        expr = self.migrate_expression(expr)
        return self._solver.min(self._constraints, expr)


Instruction:
Can you tell what is the following Python 3 function doing
def solve_minmax(self, expr):
        if isinstance(expr, int):
            return expr
        expr = self.migrate_expression(expr)
        return self._solver.minmax(self._constraints, expr)

Response:
Solves a symbolic value into
        its minimum and maximun solution. Only defined for bitvects.


Instruction:
Make a summary of the following Python 3 code
def solve_buffer(self, addr, nbytes, constrain=False):
        buffer = self.cpu.read_bytes(addr, nbytes)
        result = []
        with self._constraints as temp_cs:
            cs_to_use = self.constraints if constrain else temp_cs
            for c in buffer:
                result.append(self._solver.get_value(cs_to_use, c))
                cs_to_use.add(c == result[-1])
        return result

Response: Reads nbytes of symbolic data from memory at addr and concretizes it.


Instruction:
Write a Python 3 function that can
mark parts of a buffer as symbolic (demarked by the wildcard byte) :param str data: The string to symbolicate. If no wildcard bytes are provided, this is the identity function on the first argument. :param str label: The label to assign to the value :param str wildcard: The byte that is considered a wildcard :param bool string: Ensure bytes returned can not be NULL :param taint: Taint identifier of the symbolicated data :type taint: tuple or frozenset :return: If data does not contain any wildcard bytes, data itself. Otherwise, a list of values derived from data. Non-wildcard bytes are kept as is, wildcard bytes are replaced by Expression objects.

Response:
def symbolicate_buffer(self, data, label='INPUT', wildcard='+', string=False, taint=frozenset()):
        """Mark parts of a buffer as symbolic (demarked by the wildcard byte)

        :param str data: The string to symbolicate. If no wildcard bytes are provided,
                this is the identity function on the first argument.
        :param str label: The label to assign to the value
        :param str wildcard: The byte that is considered a wildcard
        :param bool string: Ensure bytes returned can not be NULL
        :param taint: Taint identifier of the symbolicated data
        :type taint: tuple or frozenset

        :return: If data does not contain any wildcard bytes, data itself. Otherwise,
            a list of values derived from data. Non-wildcard bytes are kept as
            is, wildcard bytes are replaced by Expression objects.
        """
        if wildcard in data:
            size = len(data)
            symb = self._constraints.new_array(name=label, index_max=size, taint=taint, avoid_collisions=True)
            self._input_symbols.append(symb)

            tmp = []
            for i in range(size):
                if data[i] == wildcard:
                    tmp.append(symb[i])
                else:
                    tmp.append(data[i])

            data = tmp

        if string:
            for b in data:
                if issymbolic(b):
                    self._constraints.add(b != 0)
                else:
                    assert b != 0
        return data


Instruction:
Given the following Python 3 function, write the documentation
def _create_emulated_mapping(self, uc, address):

        m = self._cpu.memory.map_containing(address)

        permissions = UC_PROT_NONE
        if 'r' in m.perms:
            permissions |= UC_PROT_READ
        if 'w' in m.perms:
            permissions |= UC_PROT_WRITE
        if 'x' in m.perms:
            permissions |= UC_PROT_EXEC

        uc.mem_map(m.start, len(m), permissions)

        self._should_be_mapped[m.start] = (len(m), permissions)

        return m

Response: Create a mapping in Unicorn and note that we ll need it if we retry.


Instruction:
Make a summary of the following Python 3 code
def _hook_xfer_mem(self, uc, access, address, size, value, data):
        assert access in (UC_MEM_WRITE, UC_MEM_READ, UC_MEM_FETCH)

        if access == UC_MEM_WRITE:
            self._cpu.write_int(address, value, size * 8)

        # If client code is attempting to read a value, we need to bring it
        # in from Manticore state. If we try to mem_write it here, Unicorn
        # will segfault. We add the value to a list of things that need to
        # be written, and ask to restart the emulation.
        elif access == UC_MEM_READ:
            value = self._cpu.read_bytes(address, size)

            if address in self._should_be_written:
                return True

            self._should_be_written[address] = value

            self._should_try_again = True
            return False

        return True

Response: Handle memory operations from unicorn.


Instruction:
Can you create a Python 3 function that
hooks for unmapped region mappings.

Response:
def _hook_unmapped(self, uc, access, address, size, value, data):
        """
        We hit an unmapped region; map it into unicorn.
        """

        try:
            m = self._create_emulated_mapping(uc, address)
        except MemoryException as e:
            self._to_raise = e
            self._should_try_again = False
            return False

        self._should_try_again = True
        return False


Instruction:
Given the following Python 3 function, write the documentation
def _interrupt(self, uc, number, data):

        from ..native.cpu.abstractcpu import Interruption  # prevent circular imports
        self._to_raise = Interruption(number)
        return True

Response: Handle software interrupt (SVC/INT)


Instruction:
Can you implement a function in Python 3 that
emulates a single instruction.

Response:
def emulate(self, instruction):
        """
        Emulate a single instruction.
        """

        # The emulation might restart if Unicorn needs to bring in a memory map
        # or bring a value from Manticore state.
        while True:

            self.reset()

            # Establish Manticore state, potentially from past emulation
            # attempts
            for base in self._should_be_mapped:
                size, perms = self._should_be_mapped[base]
                self._emu.mem_map(base, size, perms)

            for address, values in self._should_be_written.items():
                for offset, byte in enumerate(values, start=address):
                    if issymbolic(byte):
                        from ..native.cpu.abstractcpu import ConcretizeMemory
                        raise ConcretizeMemory(self._cpu.memory, offset, 8,
                                               "Concretizing for emulation")

                self._emu.mem_write(address, b''.join(values))

            # Try emulation
            self._should_try_again = False

            self._step(instruction)

            if not self._should_try_again:
                break


Instruction:
Here you have a function in Python 3, explain what it does
def _step(self, instruction):
        logger.debug("0x%x:\t%s\t%s"
                     % (instruction.address, instruction.mnemonic, instruction.op_str))

        registers = set(self._cpu.canonical_registers)

        # Refer to EFLAGS instead of individual flags for x86
        if self._cpu.arch == CS_ARCH_X86:
            # The last 8 canonical registers of x86 are individual flags; replace
            # with the eflags
            registers -= set(['CF', 'PF', 'AF', 'ZF', 'SF', 'IF', 'DF', 'OF'])
            registers.add('EFLAGS')

            # TODO(mark): Unicorn 1.0.1 does not support reading YMM registers,
            # and simply returns back zero. If a unicorn emulated instruction writes to an
            # XMM reg, we will read back the corresponding YMM register, resulting in an
            # incorrect zero value being actually written to the XMM register. This is
            # fixed in Unicorn PR #819, so when that is included in a release, delete
            # these two lines.
            registers -= set(['YMM0', 'YMM1', 'YMM2', 'YMM3', 'YMM4', 'YMM5', 'YMM6', 'YMM7',
                              'YMM8', 'YMM9', 'YMM10', 'YMM11', 'YMM12', 'YMM13', 'YMM14', 'YMM15'])
            registers |= set(['XMM0', 'XMM1', 'XMM2', 'XMM3', 'XMM4', 'XMM5', 'XMM6', 'XMM7',
                              'XMM8', 'XMM9', 'XMM10', 'XMM11', 'XMM12', 'XMM13', 'XMM14', 'XMM15'])

        # XXX(yan): This concretizes the entire register state. This is overly
        # aggressive. Once capstone adds consistent support for accessing
        # referred registers, make this only concretize those registers being
        # read from.
        for reg in registers:
            val = self._cpu.read_register(reg)
            if issymbolic(val):
                from ..native.cpu.abstractcpu import ConcretizeRegister
                raise ConcretizeRegister(self._cpu, reg, "Concretizing for emulation.",
                                         policy='ONE')
            self._emu.reg_write(self._to_unicorn_id(reg), val)

        # Bring in the instruction itself
        instruction = self._cpu.decode_instruction(self._cpu.PC)
        text_bytes = self._cpu.read_bytes(self._cpu.PC, instruction.size)
        self._emu.mem_write(self._cpu.PC, b''.join(text_bytes))

        self._emu.hook_add(UC_HOOK_MEM_READ_UNMAPPED, self._hook_unmapped)
        self._emu.hook_add(UC_HOOK_MEM_WRITE_UNMAPPED, self._hook_unmapped)
        self._emu.hook_add(UC_HOOK_MEM_FETCH_UNMAPPED, self._hook_unmapped)
        self._emu.hook_add(UC_HOOK_MEM_READ, self._hook_xfer_mem)
        self._emu.hook_add(UC_HOOK_MEM_WRITE, self._hook_xfer_mem)
        self._emu.hook_add(UC_HOOK_INTR, self._interrupt)

        saved_PC = self._cpu.PC

        try:
            pc = self._cpu.PC
            if self._cpu.arch == CS_ARCH_ARM and self._uc_mode == UC_MODE_THUMB:
                pc |= 1
            self._emu.emu_start(pc, self._cpu.PC + instruction.size, count=1)
        except UcError as e:
            # We request re-execution by signaling error; if we we didn't set
            # _should_try_again, it was likely an actual error
            if not self._should_try_again:
                raise

        if self._should_try_again:
            return

        if logger.isEnabledFor(logging.DEBUG):
            logger.debug("=" * 10)
            for register in self._cpu.canonical_registers:
                logger.debug(
                    f"Register {register:3s}  "
                    f"Manticore: {self._cpu.read_register(register):08x}, "
                    f"Unicorn {self._emu.reg_read(self._to_unicorn_id(register)):08x}"
                )
            logger.debug(">" * 10)

        # Bring back Unicorn registers to Manticore
        for reg in registers:
            val = self._emu.reg_read(self._to_unicorn_id(reg))
            self._cpu.write_register(reg, val)

        # Unicorn hack. On single step, unicorn wont advance the PC register
        mu_pc = self.get_unicorn_pc()
        if saved_PC == mu_pc:
            self._cpu.PC = saved_PC + instruction.size

        # Raise the exception from a hook that Unicorn would have eaten
        if self._to_raise:
            raise self._to_raise

        return

Response: A single instruction at executing an unicorn internal state machine.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def rlp_encode(item):
    if item is None or item == 0:
        ret = b'\x80'
    elif isinstance(item, str):
        ret = rlp_encode(item.encode('utf8'))
    elif isinstance(item, (bytearray, bytes)):
        if len(item) == 1 and item[0] < 0x80:
            # For a single byte whose value is in the [0x00, 0x7f] range, that byte is its own RLP encoding.
            ret = item
        else:
            ret = encode_length(len(item), 0x80) + item
    elif isinstance(item, collections.abc.Sequence):
        output = b''.join(map(rlp_encode, item))
        ret = encode_length(len(output), 0xC0) + output
    elif isinstance(item, int):
        ret = rlp_encode(int_to_bytes(item))
    else:
        raise Exception("Cannot encode object of type %s" % type(item).__name__)
    return ret

Response: r Encode the object to be encoded in RLP.


Instruction:
Can you tell what is the following Python 3 function doing
def must_be_true(self, constraints, expression) -> bool:
        solutions = self.get_all_values(constraints, expression, maxcnt=2, silent=True)
        return solutions == [True]

Response: Check if expression is True and that it can not be False with current constraints


Instruction:
Can you tell what is the following Python 3 function doing
def max(self, constraints, X: BitVec, M=10000):
        assert isinstance(X, BitVec)
        return self.optimize(constraints, X, 'maximize', M)

Response: Iteratively finds the maximum value for a symbol within given constraints.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def minmax(self, constraints, x, iters=10000):
        if issymbolic(x):
            m = self.min(constraints, x, iters)
            M = self.max(constraints, x, iters)
            return m, M
        else:
            return x, x

Response: Returns the min and max possible values for x within given constraints


Instruction:
Given the following Python 3 function, write the documentation
def _solver_version(self) -> Version:
        self._reset()
        if self._received_version is None:
            self._send('(get-info :version)')
            self._received_version = self._recv()
        key, version = shlex.split(self._received_version[1:-1])
        return Version(*map(int, version.split('.')))

Response: Parse the version from z3


Instruction:
Implement a Python 3 function for
spawning z3 solver process

Response:
def _start_proc(self):
        """Spawns z3 solver process"""
        assert '_proc' not in dir(self) or self._proc is None
        try:
            self._proc = Popen(shlex.split(self._command), stdin=PIPE, stdout=PIPE, bufsize=0, universal_newlines=True)
        except OSError as e:
            print(e, "Probably too many cached expressions? visitors._cache...")
            # Z3 was removed from the system in the middle of operation
            raise Z3NotFoundError  # TODO(mark) don't catch this exception in two places

        # run solver specific initializations
        for cfg in self._init:
            self._send(cfg)


Instruction:
Can you tell what is the following Python 3 function doing
def _stop_proc(self):
        if self._proc is None:
            return
        if self._proc.returncode is None:
            try:
                self._send("(exit)")
            except (SolverError, IOError) as e:
                # z3 was too fast to close
                logger.debug(str(e))
            finally:
                try:
                    self._proc.stdin.close()
                except IOError as e:
                    logger.debug(str(e))
                try:
                    self._proc.stdout.close()
                except IOError as e:
                    logger.debug(str(e))
                self._proc.kill()
                # Wait for termination, to avoid zombies.
                self._proc.wait()

        self._proc: Popen = None

Response: Stops the z3 solver process by sending an exit command to it and then waiting till the process terminates.


Instruction:
Write a Python 3 script to
send a string to the solver.

Response:
def _send(self, cmd: str):
        """
        Send a string to the solver.

        :param cmd: a SMTLIBv2 command (ex. (check-sat))
        """
        logger.debug('>%s', cmd)
        try:
            self._proc.stdout.flush()
            self._proc.stdin.write(f'{cmd}\n')
        except IOError as e:
            raise SolverError(str(e))


Instruction:
Explain what the following Python 3 code does
def _recv(self) -> str:
        buf, left, right = self.__readline_and_count()
        bufl = [buf]

        while left != right:
            buf, l, r = self.__readline_and_count()
            bufl.append(buf)
            left += l
            right += r

        buf = ''.join(bufl).strip()

        logger.debug('<%s', buf)
        if '(error' in bufl[0]:
            raise Exception(f"Error in smtlib: {bufl[0]}")
        return buf

Response: Reads the response from the solver


Instruction:
Make a summary of the following Python 3 code
def _is_sat(self) -> bool:
        logger.debug("Solver.check() ")
        start = time.time()
        self._send('(check-sat)')
        status = self._recv()
        logger.debug("Check took %s seconds (%s)", time.time() - start, status)
        if status not in ('sat', 'unsat', 'unknown'):
            raise SolverError(status)
        if consider_unknown_as_unsat:
            if status == 'unknown':
                logger.info('Found an unknown core, probably a solver timeout')
                status = 'unsat'

        if status == 'unknown':
            raise SolverUnknown(status)

        return status == 'sat'

Response: Check the satisfiability of the current state of the current system.


Instruction:
How would you explain what the following Python 3 function does
def _assert(self, expression: Bool):
        assert isinstance(expression, Bool)
        smtlib = translate_to_smtlib(expression)
        self._send('(assert %s)' % smtlib)

Response: Auxiliary method to send an assert


Instruction:
Can you tell what is the following Python 3 function doing
def _getvalue(self, expression):
        if not issymbolic(expression):
            return expression
        assert isinstance(expression, Variable)

        if isinstance(expression, Array):
            result = bytearray()
            for c in expression:
                expression_str = translate_to_smtlib(c)
                self._send('(get-value (%s))' % expression_str)
                response = self._recv()
                result.append(int('0x{:s}'.format(response.split(expression_str)[1][3:-2]), 16))
            return bytes(result)
        else:
            self._send('(get-value (%s))' % expression.name)
            ret = self._recv()
            assert ret.startswith('((') and ret.endswith('))'), ret

            if isinstance(expression, Bool):
                return {'true': True, 'false': False}[ret[2:-2].split(' ')[1]]
            elif isinstance(expression, BitVec):
                pattern, base = self._get_value_fmt
                m = pattern.match(ret)
                expr, value = m.group('expr'), m.group('value')
                return int(value, base)

        raise NotImplementedError("_getvalue only implemented for Bool and BitVec")

Response: Ask the solver for one possible assignment for given expression.


Instruction:
Explain what the following Python 3 code does
def can_be_true(self, constraints, expression):
        if isinstance(expression, bool):
            if not expression:
                return expression
            else:
                # if True check if constraints are feasible
                self._reset(constraints)
                return self._is_sat()
        assert isinstance(expression, Bool)

        with constraints as temp_cs:
            temp_cs.add(expression)
            self._reset(temp_cs.to_string(related_to=expression))
            return self._is_sat()

Response: Check if two potentially symbolic values can be equal


Instruction:
Create a Python 3 function for
returning a list with all possible values for the symbol x

Response:
def get_all_values(self, constraints, expression, maxcnt=None, silent=False):
        """Returns a list with all the possible values for the symbol x"""
        if not isinstance(expression, Expression):
            return [expression]
        assert isinstance(constraints, ConstraintSet)
        assert isinstance(expression, Expression)
        expression = simplify(expression)
        if maxcnt is None:
            maxcnt = consts.maxsolutions

        with constraints as temp_cs:
            if isinstance(expression, Bool):
                var = temp_cs.new_bool()
            elif isinstance(expression, BitVec):
                var = temp_cs.new_bitvec(expression.size)
            elif isinstance(expression, Array):
                var = temp_cs.new_array(index_max=expression.index_max, value_bits=expression.value_bits, taint=expression.taint).array
            else:
                raise NotImplementedError(f"get_all_values only implemented for {type(expression)} expression type.")

            temp_cs.add(var == expression)
            self._reset(temp_cs.to_string(related_to=var))

            result = []

            while self._is_sat():
                value = self._getvalue(var)
                result.append(value)
                self._assert(var != value)

                if len(result) >= maxcnt:
                    if silent:
                        # do not throw an exception if set to silent
                        # Default is not silent, assume user knows
                        # what they are doing and will check the size
                        # of returned vals list (previous smtlib behavior)
                        break
                    else:
                        raise TooManySolutions(result)

            return result


Instruction:
Can you write a function in Python 3 where it
asks the solver for one possible result of given expression.

Response:
def get_value(self, constraints, expression):
        """
        Ask the solver for one possible result of given expression using given set of constraints.
        """
        if not issymbolic(expression):
            return expression
        assert isinstance(expression, (Bool, BitVec, Array))
        with constraints as temp_cs:
            if isinstance(expression, Bool):
                var = temp_cs.new_bool()
            elif isinstance(expression, BitVec):
                var = temp_cs.new_bitvec(expression.size)
            elif isinstance(expression, Array):
                var = []
                result = []
                for i in range(expression.index_max):
                    subvar = temp_cs.new_bitvec(expression.value_bits)
                    var.append(subvar)
                    temp_cs.add(subvar == simplify(expression[i]))

                self._reset(temp_cs)
                if not self._is_sat():
                    raise SolverError('Model is not available')

                for i in range(expression.index_max):
                    self._send('(get-value (%s))' % var[i].name)
                    ret = self._recv()
                    assert ret.startswith('((') and ret.endswith('))')
                    pattern, base = self._get_value_fmt
                    m = pattern.match(ret)
                    expr, value = m.group('expr'), m.group('value')
                    result.append(int(value, base))
                return bytes(result)

            temp_cs.add(var == expression)

            self._reset(temp_cs)

        if not self._is_sat():
            raise SolverError('Model is not available')

        self._send('(get-value (%s))' % var.name)
        ret = self._recv()
        if not (ret.startswith('((') and ret.endswith('))')):
            raise SolverError('SMTLIB error parsing response: %s' % ret)

        if isinstance(expression, Bool):
            return {'true': True, 'false': False}[ret[2:-2].split(' ')[1]]
        if isinstance(expression, BitVec):
            pattern, base = self._get_value_fmt
            m = pattern.match(ret)
            expr, value = m.group('expr'), m.group('value')
            return int(value, base)
        raise NotImplementedError("get_value only implemented for Bool and BitVec")


Instruction:
Explain what the following Python 3 code does
def summarized_name(self, name):
        components = name.split('.')
        prefix = '.'.join(c[0] for c in components[:-1])
        return f'{prefix}.{components[-1]}'

Response: Produce a summarized record name by splitting it into a prefix and suffix.


Instruction:
Can you generate the documentation for the following Python 3 function
def colored_level_name(self, levelname):
        if self.colors_disabled:
            return self.plain_levelname_format.format(levelname)
        else:
            return self.colored_levelname_format.format(self.color_map[levelname], levelname)

Response: Colors the logging level in the log record


Instruction:
Explain what the following Python 3 code does
def strlen(state, s):

    cpu = state.cpu

    if issymbolic(s):
        raise ConcretizeArgument(state.cpu, 1)

    zero_idx = _find_zero(cpu, state.constraints, s)

    ret = zero_idx

    for offset in range(zero_idx - 1, -1, -1):
        byt = cpu.read_int(s + offset, 8)
        if issymbolic(byt):
            ret = ITEBV(cpu.address_bit_size, byt == 0, offset, ret)

    return ret

Response: Walks from the end of string and returns the length of the string.


Instruction:
Explain what the following Python 3 code does
def all_events(cls):
        all_evts = set()
        for cls, evts in cls.__all_events__.items():
            all_evts.update(evts)
        return all_evts

Response: Return all events that all subclasses have so far registered to publish.


Instruction:
How would you implement a function in Python 3 that
returns the shared context.

Response:
def context(self):
        """ Convenient access to shared context """
        if self._context is not None:
            return self._context
        else:
            logger.warning("Using shared context without a lock")
            return self._executor._shared_context


Instruction:
Can you implement a function in Python 3 that
returns a pstats. Stats instance with profiling results if run was called with should_profile = True. Otherwise returns None.

Response:
def get_profiling_stats(self):
        """
        Returns a pstat.Stats instance with profiling results if `run` was called with `should_profile=True`.
        Otherwise, returns `None`.
        """
        profile_file_path = os.path.join(self.workspace, 'profiling.bin')
        try:
            return pstats.Stats(profile_file_path)
        except Exception as e:
            logger.debug(f'Failed to get profiling stats: {e}')
            return None


Instruction:
How would you explain what the following Python 3 function does
def run(self, procs=1, timeout=None, should_profile=False):
        assert not self.running, "Manticore is already running."
        self._start_run()

        self._last_run_stats['time_started'] = time.time()
        with self.shutdown_timeout(timeout):
            self._start_workers(procs, profiling=should_profile)

            self._join_workers()
        self._finish_run(profiling=should_profile)

Response:
Runs analysis.

        :param int procs: Number of parallel worker processes
        :param timeout: Analysis timeout, in seconds


Instruction:
Can you implement a function in Python 3 that
dispatches execution into one of Manticore s engines evm or native.

Response:
def main():
    """
    Dispatches execution into one of Manticore's engines: evm or native.
    """
    args = parse_arguments()

    if args.no_colors:
        log.disable_colors()

    sys.setrecursionlimit(consts.recursionlimit)

    ManticoreBase.verbosity(args.v)

    if args.argv[0].endswith('.sol'):
        ethereum_main(args, logger)
    else:
        install_helper.ensure_native_deps()
        native_main(args, logger)


Instruction:
Explain what the following Python 3 code does
def GetNBits(value, nbits):
    # NOP if sizes are the same
    if isinstance(value, int):
        return Operators.EXTRACT(value, 0, nbits)
    elif isinstance(value, BitVec):
        if value.size < nbits:
            return Operators.ZEXTEND(value, nbits)
        else:
            return Operators.EXTRACT(value, 0, nbits)

Response: Get the first nbits bits from value.


Instruction:
Explain what the following Python 3 code does
def SInt(value, width):
    return Operators.ITEBV(width, Bit(value, width - 1) == 1,
                           GetNBits(value, width) - 2**width,
                           GetNBits(value, width))

Response:
Convert a bitstring value of width bits to a signed integer
    representation.


Instruction:
Can you tell what is the following Python 3 function doing
def LSL_C(value, amount, width):
    assert amount > 0
    value = Operators.ZEXTEND(value, width * 2)
    shifted = value << amount
    result = GetNBits(shifted, width)
    carry = Bit(shifted, width)
    return (result, carry)

Response: This function performs the ARM LSL_C operation.


Instruction:
Given the following Python 3 function, write the documentation
def LSL(value, amount, width):
    if amount == 0:
        return value

    result, _ = LSL_C(value, amount, width)
    return result

Response: This function performs the ARM LSL operation.


Instruction:
How would you explain what the following Python 3 function does
def LSR(value, amount, width):
    if amount == 0:
        return value
    result, _ = LSR_C(value, amount, width)
    return result

Response: This function performs the ARM LSR ( logical shift right operation.


Instruction:
Here you have a function in Python 3, explain what it does
def ASR_C(value, amount, width):
    assert amount <= width
    assert amount > 0
    assert amount + width <= width * 2
    value = Operators.SEXTEND(value, width, width * 2)
    result = GetNBits(value >> amount, width)
    carry = Bit(value, amount - 1)
    return (result, carry)

Response: This function performs the ARM ASR_C operation.


Instruction:
Here you have a function in Python 3, explain what it does
def ROR_C(value, amount, width):
    assert amount <= width
    assert amount > 0
    m = amount % width
    right, _ = LSR_C(value, m, width)
    left, _ = LSL_C(value, width - m, width)
    result = left | right
    carry = Bit(result, width - 1)
    return (result, carry)

Response: The ARM ROR_C operation.


Instruction:
Make a summary of the following Python 3 code
def RRX_C(value, carry, width):
    carry_out = Bit(value, 0)
    result = (value >> 1) | (carry << (width - 1))
    return (result, carry_out)

Response: The ARM RRX C operation.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def RRX(value, carry, width):
    result, _ = RRX_C(value, carry, width)
    return result

Response: The ARM RRX operation.


Instruction:
Write a Python 3 script for
returning a shared context dictionary.

Response:
def locked_context(self, key=None, default=dict):
        """ Policy shared context dictionary """
        keys = ['policy']
        if key is not None:
            keys.append(key)
        with self._executor.locked_context('.'.join(keys), default) as policy_context:
            yield policy_context


Instruction:
Write a Python 3 script for
adding a callback to be called when a state is received.

Response:
def _add_state_callback(self, state_id, state):
        """ Save summarize(state) on policy shared context before
            the state is stored
        """
        summary = self.summarize(state)
        if summary is None:
            return
        with self.locked_context('summaries', dict) as ctx:
            ctx[state_id] = summary


Instruction:
Can you tell what is the following Python 3 function doing
def _visited_callback(self, state, pc, instr):
        with self.locked_context('visited', set) as ctx:
            ctx.add(pc)

Response: Called when a PC is visited.


Instruction:
Can you generate the documentation for the following Python 3 function
def _visited_callback(self, state, pc, instr):
        pc = state.platform.current.PC
        with self.locked_context('visited', dict) as ctx:
            ctx[pc] = ctx.get(pc, 0) + 1

Response: Set the visited set as the current PC.


Instruction:
Explain what the following Python 3 code does
def locked_context(self, key=None, default=dict):
        assert default in (list, dict, set)
        with self._lock:
            if key is None:
                yield self._shared_context
            else:
                sub_context = self._shared_context.get(key, None)
                if sub_context is None:
                    sub_context = default()
                yield sub_context
                self._shared_context[key] = sub_context

Response: A context is a shared memory object. All workers share this. A shared memory object. All workers share this. A shared memory object. All workers share this. A shared memory object. All workers share this. A shared memory object. All workers share this. A shared memory object.


Instruction:
Implement a function in Python 3 to
return the next available state with the max priority.

Response:
def get(self):
        """ Dequeue a state with the max priority """

        # A shutdown has been requested
        if self.is_shutdown():
            return None

        # if not more states in the queue, let's wait for some forks
        while len(self._states) == 0:
            # if no worker is running, bail out
            if self.running == 0:
                return None
            # if a shutdown has been requested, bail out
            if self.is_shutdown():
                return None
            # if there ares actually some workers running, wait for state forks
            logger.debug("Waiting for available states")
            self._lock.wait()

        state_id = self._policy.choice(list(self._states))
        if state_id is None:
            return None
        del self._states[self._states.index(state_id)]
        return state_id


Instruction:
Can you generate the documentation for the following Python 3 function
def fork(self, state, expression, policy='ALL', setstate=None):
        assert isinstance(expression, Expression)

        if setstate is None:
            setstate = lambda x, y: None

        # Find a set of solutions for expression
        solutions = state.concretize(expression, policy)

        if not solutions:
            raise ExecutorError("Forking on unfeasible constraint set")

        if len(solutions) == 1:
            setstate(state, solutions[0])
            return state

        logger.info("Forking. Policy: %s. Values: %s",
                    policy,
                    ', '.join(f'0x{sol:x}' for sol in solutions))

        self._publish('will_fork_state', state, expression, solutions, policy)

        # Build and enqueue a state for each solution
        children = []
        for new_value in solutions:
            with state as new_state:
                new_state.constrain(expression == new_value)

                # and set the PC of the new state to the concrete pc-dest
                #(or other register or memory address to concrete)
                setstate(new_state, new_value)

                self._publish('did_fork_state', new_state, expression, new_value, policy)

                # enqueue new_state
                state_id = self.enqueue(new_state)
                # maintain a list of children for logging purpose
                children.append(state_id)

        logger.info("Forking current state into states %r", children)
        return None

Response: Forks a state on a given expression.


Instruction:
How would you code a function in Python 3 to
create a new instance of a Linux state machine.

Response:
def linux(cls, path, argv=None, envp=None, entry_symbol=None, symbolic_files=None, concrete_start='', pure_symbolic=False, stdin_size=None, **kwargs):
        """
        Constructor for Linux binary analysis.

        :param str path: Path to binary to analyze
        :param argv: Arguments to provide to the binary
        :type argv: list[str]
        :param envp: Environment to provide to the binary
        :type envp: dict[str, str]
        :param entry_symbol: Entry symbol to resolve to start execution
        :type envp: str
        :param symbolic_files: Filenames to mark as having symbolic input
        :type symbolic_files: list[str]
        :param str concrete_start: Concrete stdin to use before symbolic input
        :param int stdin_size: symbolic stdin size to use
        :param kwargs: Forwarded to the Manticore constructor
        :return: Manticore instance, initialized with a Linux State
        :rtype: Manticore
        """
        if stdin_size is None:
            stdin_size = consts.stdin_size

        try:
            return cls(_make_linux(path, argv, envp, entry_symbol, symbolic_files, concrete_start, pure_symbolic, stdin_size), **kwargs)
        except elftools.common.exceptions.ELFError:
            raise Exception(f'Invalid binary: {path}')


Instruction:
Can you create a Python 3 function that
adds a callback to be invoked on executing a program counter. Pass None for pc to invoke callback on every instruction. Pass None for pc to invoke callback on every instruction.

Response:
def add_hook(self, pc, callback):
        """
        Add a callback to be invoked on executing a program counter. Pass `None`
        for pc to invoke callback on every instruction. `callback` should be a callable
        that takes one :class:`~manticore.core.state.State` argument.

        :param pc: Address of instruction to hook
        :type pc: int or None
        :param callable callback: Hook function
        """
        if not (isinstance(pc, int) or pc is None):
            raise TypeError(f"pc must be either an int or None, not {pc.__class__.__name__}")
        else:
            self._hooks.setdefault(pc, set()).add(callback)
            if self._hooks:
                self._executor.subscribe('will_execute_instruction', self._hook_callback)


Instruction:
How would you code a function in Python 3 to
invoke all registered generic hooks

Response:
def _hook_callback(self, state, pc, instruction):
        'Invoke all registered generic hooks'

        # Ignore symbolic pc.
        # TODO(yan): Should we ask the solver if any of the hooks are possible,
        # and execute those that are?

        if issymbolic(pc):
            return

        # Invoke all pc-specific hooks
        for cb in self._hooks.get(pc, []):
            cb(state)

        # Invoke all pc-agnostic hooks
        for cb in self._hooks.get(None, []):
            cb(state)


Instruction:
How would you implement a function in Python 3 that
gets a configuration variable group named name.

Response:
def get_group(name: str) -> _Group:
    """
    Get a configuration variable group named |name|
    """
    global _groups

    if name in _groups:
        return _groups[name]

    group = _Group(name)
    _groups[name] = group

    return group


Instruction:
Implement a function in Python 3 to
save current config state to a yml file stream identified by f

Response:
def save(f):
    """
    Save current config state to an yml file stream identified by |f|

    :param f: where to write the config file
    """
    global _groups

    c = {}
    for group_name, group in _groups.items():
        section = {var.name: var.value for var in group.updated_vars()}
        if not section:
            continue
        c[group_name] = section

    yaml.safe_dump(c, f, line_break=True)


Instruction:
Can you implement a function in Python 3 that
loads an yml - formatted configuration from file stream |f|

Response:
def parse_config(f):
    """
    Load an yml-formatted configuration from file stream |f|

    :param file f: Where to read the config.
    """

    try:
        c = yaml.safe_load(f)
        for section_name, section in c.items():
            group = get_group(section_name)

            for key, val in section.items():
                group.update(key)
                setattr(group, key, val)
    # Any exception here should trigger the warning; from not being able to parse yaml
    # to reading poorly formatted values
    except Exception:
        raise ConfigError("Failed reading config file. Do you have a local [.]manticore.yml file?")


Instruction:
Here you have a function in Python 3, explain what it does
def load_overrides(path=None):

    if path is not None:
        names = [path]
    else:
        possible_names = ['mcore.yml', 'manticore.yml']
        names = [os.path.join('.', ''.join(x)) for x in product(['', '.'], possible_names)]

    for name in names:
        try:
            with open(name, 'r') as yml_f:
                logger.info(f'Reading configuration from {name}')
                parse_config(yml_f)
            break
        except FileNotFoundError:
            pass
    else:
        if path is not None:
            raise FileNotFoundError(f"'{path}' not found for config overrides")

Response: Load config overrides from the yml file at path or from default paths.


Instruction:
How would you explain what the following Python 3 function does
def add_config_vars_to_argparse(args):
    global _groups
    for group_name, group in _groups.items():
        for key in group:
            obj = group._var_object(key)
            args.add_argument(f"--{group_name}.{key}", type=type(obj.default),
                              default=obj.default, help=obj.description)

Response: Adds all defined config vars into args.


Instruction:
Write a Python 3 script for
bringing in provided config values to the args parser, and import entries to the config from all arguments that were actually passed on the command line :param parser: The arg parser :param args: The value that parser.parse_args returned

Response:
def process_config_values(parser: argparse.ArgumentParser, args: argparse.Namespace):
    """
    Bring in provided config values to the args parser, and import entries to the config
    from all arguments that were actually passed on the command line

    :param parser: The arg parser
    :param args: The value that parser.parse_args returned
    """
    # First, load a local config file, if passed or look for one in pwd if it wasn't.
    load_overrides(args.config)

    # Get a list of defined config vals. If these are passed on the command line,
    # update them in their correct group, not in the cli group
    defined_vars = list(get_config_keys())

    command_line_args = vars(args)

    # Bring in the options keys into args
    config_cli_args = get_group('cli')

    # Place all command line args into the cli group (for saving in the workspace). If
    # the value is set on command line, then it takes precedence; otherwise we try to
    # read it from the config file's cli group.
    for k in command_line_args:
        default = parser.get_default(k)
        set_val = getattr(args, k)
        if default is not set_val:
            if k not in defined_vars:
                config_cli_args.update(k, value=set_val)
            else:
                # Update a var's native group
                group_name, key = k.split('.')
                group = get_group(group_name)
                setattr(group, key, set_val)
        else:
            if k in config_cli_args:
                setattr(args, k, getattr(config_cli_args, k))


Instruction:
Can you create a Python 3 function that
adds a variable to this value group optionally giving it a default value and a description.

Response:
def add(self, name: str, default=None, description: str=None):
        """
        Add a variable named |name| to this value group, optionally giving it a
        default value and a description.

        Variables must be added with this method before they can be set or read.
        Reading a variable replaces the variable that was defined previously, but
        updates the description if a new one is set.

        """
        if name in self._vars:
            raise ConfigError(f"{self.name}.{name} already defined.")

        if name == 'name':
            raise ConfigError("'name' is a reserved name for a group.")

        v = _Var(name, description=description, default=default)
        self._vars[name] = v


Instruction:
Make a summary of the following Python 3 code
def update(self, name: str, value=None, default=None, description: str=None):
        if name in self._vars:
            description = description or self._vars[name].description
            default = default or self._vars[name].default
        elif name == 'name':
            raise ConfigError("'name' is a reserved name for a group.")

        v = _Var(name, description=description, default=default, defined=False)
        v.value = value
        self._vars[name] = v

Response: Update the value of a key in the config.


Instruction:
Explain what the following Python 3 code does
def get_description(self, name: str) -> str:
        if name not in self._vars:
            raise ConfigError(f"{self.name}.{name} not defined.")

        return self._vars[name].description

Response: Return the description of the variable identified by name or a help string of variable identified by name.


Instruction:
Can you write a function in Python 3 where it
communicates with the child process without closing stdin.

Response:
def correspond(text):
    """Communicate with the child process without closing stdin."""
    subproc.stdin.write(text)
    subproc.stdin.flush()
    return drain()


Instruction:
How would you code a function in Python 3 to
return the function signature for the specified name and Solidity JSON metadata inputs array.

Response:
def function_signature_for_name_and_inputs(name: str, inputs: Sequence[Mapping[str, Any]]) -> str:
        """Returns the function signature for the specified name and Solidity JSON metadata inputs array.

        The ABI specification defines the function signature as the function name followed by the parenthesised list of
        parameter types separated by single commas and no spaces.
        See https://solidity.readthedocs.io/en/latest/abi-spec.html#function-selector
        """
        return name + SolidityMetadata.tuple_signature_for_components(inputs)


Instruction:
Can you generate a brief explanation for the following Python 3 code
def tuple_signature_for_components(components: Sequence[Mapping[str, Any]]) -> str:
        ts = []
        for c in components:
            t: str = c['type']
            if t.startswith('tuple'):
                assert len(t) == 5 or t[5] == '['
                t = SolidityMetadata.tuple_signature_for_components(c['components']) + t[5:]
            ts.append(t)
        return f'({",".join(ts)})'

Response: Equivalent to function_signature_for_name_and_inputs ( name and inputs components )


Instruction:
How would you explain what the following Python 3 function does
def get_constructor_arguments(self) -> str:
        item = self._constructor_abi_item
        return '()' if item is None else self.tuple_signature_for_components(item['inputs'])

Response: Returns the tuple type signature for the arguments of the contract constructor.


Instruction:
Make a summary of the following Python 3 code
def get_source_for(self, asm_offset, runtime=True):
        srcmap = self.get_srcmap(runtime)

        try:
            beg, size, _, _ = srcmap[asm_offset]
        except KeyError:
            #asm_offset pointing outside the known bytecode
            return ''

        output = ''
        nl = self.source_code[:beg].count('\n') + 1
        snippet = self.source_code[beg:beg + size]
        for l in snippet.split('\n'):
            output += '    %s  %s\n' % (nl, l)
            nl += 1
        return output

Response: Return the source code snippet related to an arbitrary offset.


Instruction:
Can you tell what is the following Python 3 function doing
def constructor_abi(self) -> Dict[str, Any]:
        item = self._constructor_abi_item
        if item:
            return dict(item)
        return {'inputs': [], 'payable': False, 'stateMutability': 'nonpayable', 'type': 'constructor'}

Response: Returns a copy of the Solidity JSON ABI item for the contract constructor.


Instruction:
Create a Python 3 function to
return a copy of the Solidity JSON ABI item for the normal contract function associated with the selector hsh.

Response:
def get_abi(self, hsh: bytes) -> Dict[str, Any]:
        """Returns a copy of the Solidity JSON ABI item for the function associated with the selector ``hsh``.

        If no normal contract function has the specified selector, a dict describing the default or non-default
        fallback function is returned.

        The content of the returned dict is described at https://solidity.readthedocs.io/en/latest/abi-spec.html#json_
        """
        if not isinstance(hsh, (bytes, bytearray)):
            raise TypeError('The selector argument must be a concrete byte array')
        sig = self._function_signatures_by_selector.get(hsh)
        if sig is not None:
            return dict(self._function_abi_items_by_signature[sig])
        item = self._fallback_function_abi_item
        if item is not None:
            return dict(item)
        # An item describing the default fallback function.
        return {'payable': False, 'stateMutability': 'nonpayable', 'type': 'fallback'}


Instruction:
Can you create a Python 3 function that
returns the tuple type signature for the arguments of the normal contract function associated with the specified selector.

Response:
def get_func_argument_types(self, hsh: bytes):
        """Returns the tuple type signature for the arguments of the function associated with the selector ``hsh``.

        If no normal contract function has the specified selector,
        the empty tuple type signature ``'()'`` is returned.
        """
        if not isinstance(hsh, (bytes, bytearray)):
            raise TypeError('The selector argument must be a concrete byte array')
        sig = self._function_signatures_by_selector.get(hsh)
        return '()' if sig is None else sig[sig.find('('):]


Instruction:
Can you generate a brief explanation for the following Python 3 code
def get_func_return_types(self, hsh: bytes) -> str:
        if not isinstance(hsh, (bytes, bytearray)):
            raise TypeError('The selector argument must be a concrete byte array')
        abi = self.get_abi(hsh)
        outputs = abi.get('outputs')
        return '()' if outputs is None else SolidityMetadata.tuple_signature_for_components(outputs)

Response: Returns the tuple type signature for the output values of the normal contract function with the specified selector.


Instruction:
Can you tell what is the following Python 3 function doing
def get_func_name(self, hsh: bytes) -> str:
        if not isinstance(hsh, (bytes, bytearray)):
            raise TypeError('The selector argument must be a concrete byte array')
        sig = self._function_signatures_by_selector.get(hsh)
        return '{fallback}' if sig is None else sig[:sig.find('(')]

Response: Returns the name of the normal function with the selector hsh.


Instruction:
Here you have a function in Python 3, explain what it does
def get_func_signature(self, hsh: bytes) -> Optional[str]:
        if not isinstance(hsh, (bytes, bytearray)):
            raise TypeError('The selector argument must be a concrete byte array')
        return self._function_signatures_by_selector.get(hsh)

Response: Returns the signature of the normal function with the selector hsh or None if no such function exists.


Instruction:
Can you generate the documentation for the following Python 3 function
def convert_permissions(m_perms):
    permissions = UC_PROT_NONE
    if 'r' in m_perms:
        permissions |= UC_PROT_READ
    if 'w' in m_perms:
        permissions |= UC_PROT_WRITE
    if 'x' in m_perms:
        permissions |= UC_PROT_EXEC
    return permissions

Response: Converts a Manticore permission string into a Unicorn permission string.


Instruction:
Can you tell what is the following Python 3 function doing
def copy_memory(self, address, size):
        start_time = time.time()
        map_bytes = self._cpu._raw_read(address, size)
        self._emu.mem_write(address, map_bytes)
        if time.time() - start_time > 3:
            logger.info(f"Copying {hr_size(size)} map at {hex(address)} took {time.time() - start_time} seconds")

Response:
Copy the bytes from address to address + size into Unicorn
        Used primarily for copying memory maps


Instruction:
Make a summary of the following Python 3 code
def map_memory_callback(self, address, size, perms, name, offset, result):
        logger.info(' '.join(("Mapping Memory @",
                              hex(address) if type(address) is int else "0x??",
                              hr_size(size), "-",
                              perms, "-",
                              f"{name}:{hex(offset) if name else ''}", "->",
                              hex(result))))
        self._emu.mem_map(address, size, convert_permissions(perms))
        self.copy_memory(address, size)

Response: Catches did_map_memory and copies the mapping into Manticore


Instruction:
Make a summary of the following Python 3 code
def protect_memory_callback(self, start, size, perms):
        logger.info(f"Changing permissions on {hex(start)}:{hex(start + size)} to {perms}")
        self._emu.mem_protect(start, size, convert_permissions(perms))

Response: Set memory protections in Unicorn correctly


Instruction:
Can you generate the documentation for the following Python 3 function
def _hook_syscall(self, uc, data):
        logger.debug(f"Stopping emulation at {hex(uc.reg_read(self._to_unicorn_id('RIP')))} to perform syscall")
        self.sync_unicorn_to_manticore()
        from ..native.cpu.abstractcpu import Syscall
        self._to_raise = Syscall()
        uc.emu_stop()

Response: Hook that transfers control to Manticore so it can execute the syscall


Instruction:
Can you generate a brief explanation for the following Python 3 code
def _hook_write_mem(self, uc, access, address, size, value, data):
        self._mem_delta[address] = (value, size)
        return True

Response: Hook for writing memory to Unicorn.


Instruction:
Create a Python 3 function to
hook for unmapped memory.

Response:
def _hook_unmapped(self, uc, access, address, size, value, data):
        """
        We hit an unmapped region; map it into unicorn.
        """
        try:
            self.sync_unicorn_to_manticore()
            logger.warning(f"Encountered an operation on unmapped memory at {hex(address)}")
            m = self._cpu.memory.map_containing(address)
            self.copy_memory(m.start, m.end - m.start)
        except MemoryException as e:
            logger.error("Failed to map memory {}-{}, ({}): {}".format(hex(address), hex(address + size), access, e))
            self._to_raise = e
            self._should_try_again = False
            return False

        self._should_try_again = True
        return False


Instruction:
Given the following Python 3 function, write the documentation
def emulate(self, instruction):

        # The emulation might restart if Unicorn needs to bring in a memory map
        # or bring a value from Manticore state.
        while True:

            # Try emulation
            self._should_try_again = False
            self._to_raise = None

            self._step(instruction)

            if not self._should_try_again:
                break

Response: Wrapper that emulates the internal state of the internal state.


Instruction:
Can you generate the documentation for the following Python 3 function
def _step(self, instruction, chunksize=0):

        try:
            pc = self._cpu.PC
            m = self._cpu.memory.map_containing(pc)
            if self._stop_at:
                logger.info(f"Emulating from {hex(pc)} to  {hex(self._stop_at)}")
            self._emu.emu_start(pc, m.end if not self._stop_at else self._stop_at, count=chunksize)
        except UcError:
            # We request re-execution by signaling error; if we we didn't set
            # _should_try_again, it was likely an actual error
            if not self._should_try_again:
                raise

        if self._should_try_again:
            return

        # self.sync_unicorn_to_manticore()
        self._cpu.PC = self.get_unicorn_pc()
        if self._cpu.PC == self._stop_at:
            logger.info("Reached emulation target, switching to Manticore mode")
            self.sync_unicorn_to_manticore()
            self._stop_at = None

        # Raise the exception from a hook that Unicorn would have eaten
        if self._to_raise:
            from ..native.cpu.abstractcpu import Syscall
            if type(self._to_raise) is not Syscall:
                logger.info("Raising %s", self._to_raise)
            raise self._to_raise

        logger.info(f"Exiting Unicorn Mode at {hex(self._cpu.PC)}")
        return

Response:
Execute a chunk of instructions starting from instruction
           .


Instruction:
Can you write a function in Python 3 where it
copies registers and written memory back into Manticore

Response:
def sync_unicorn_to_manticore(self):
        """
        Copy registers and written memory back into Manticore
        """
        self.write_backs_disabled = True
        for reg in self.registers:
            val = self._emu.reg_read(self._to_unicorn_id(reg))
            self._cpu.write_register(reg, val)
        if len(self._mem_delta) > 0:
            logger.debug(f"Syncing {len(self._mem_delta)} writes back into Manticore")
        for location in self._mem_delta:
            value, size = self._mem_delta[location]
            self._cpu.write_int(location, value, size * 8)
        self.write_backs_disabled = False
        self._mem_delta = {}


Instruction:
Write a Python 3 script for
copying memory writes from Manticore back into Unicorn in real - time

Response:
def write_back_memory(self, where, expr, size):
        """ Copy memory writes from Manticore back into Unicorn in real-time """
        if self.write_backs_disabled:
            return
        if type(expr) is bytes:
            self._emu.mem_write(where, expr)
        else:
            if issymbolic(expr):
                data = [Operators.CHR(Operators.EXTRACT(expr, offset, 8)) for offset in range(0, size, 8)]
                concrete_data = []
                for c in data:
                    if issymbolic(c):
                        c = chr(solver.get_value(self._cpu.memory.constraints, c))
                    concrete_data.append(c)
                data = concrete_data
            else:
                data = [Operators.CHR(Operators.EXTRACT(expr, offset, 8)) for offset in range(0, size, 8)]
            logger.debug(f"Writing back {hr_size(size // 8)} to {hex(where)}: {data}")
            # TODO - the extra encoding is to handle null bytes output as strings when we concretize. That's probably a bug.
            self._emu.mem_write(where, b''.join(b.encode('utf-8') if type(b) is str else b for b in data))


Instruction:
Given the following Python 3 function, write the documentation
def write_back_register(self, reg, val):
        if self.write_backs_disabled:
            return
        if issymbolic(val):
            logger.warning("Skipping Symbolic write-back")
            return
        if reg in self.flag_registers:
            self._emu.reg_write(self._to_unicorn_id('EFLAGS'), self._cpu.read_register('EFLAGS'))
            return
        self._emu.reg_write(self._to_unicorn_id(reg), val)

Response: Write back a register.


Instruction:
Here you have a function in Python 3, explain what it does
def update_segment(self, selector, base, size, perms):
        logger.info("Updating selector %s to 0x%02x (%s bytes) (%s)", selector, base, size, perms)
        if selector == 99:
            self.set_fs(base)
        else:
            logger.error("No way to write segment: %d", selector)

Response: Update the internal state of the current segment.


Instruction:
How would you explain what the following Python 3 function does
def flip(constraint):
    '''
    flips a constraint (Equal)

    (Equal (BitVecITE Cond IfC ElseC) IfC)
        ->
    (Equal (BitVecITE Cond IfC ElseC) ElseC)
    '''
    equal = copy.copy(constraint)

    assert len(equal.operands) == 2
    # assume they are the equal -> ite form that we produce on standard branches
    ite, forcepc = equal.operands
    assert isinstance(ite, BitVecITE) and isinstance(forcepc, BitVecConstant)
    assert len(ite.operands) == 3
    cond, iifpc, eelsepc = ite.operands
    assert isinstance(iifpc, BitVecConstant) and isinstance(eelsepc, BitVecConstant)

    equal._operands= (equal.operands[0], eelsepc if forcepc.value == iifpc.value else iifpc)

    return equal

Response: Flips a constraint into a single node.


Instruction:
Write a Python 3 function that can
generate permutations of lst where permutations are mutated by func. Used for flipping constraints.

Response:
def perm(lst, func):
    ''' Produce permutations of `lst`, where permutations are mutated by `func`. Used for flipping constraints. highly
    possible that returned constraints can be unsat this does it blindly, without any attention to the constraints
    themselves

    Considering lst as a list of constraints, e.g.

      [ C1, C2, C3 ]

    we'd like to consider scenarios of all possible permutations of flipped constraints, excluding the original list.
    So we'd like to generate:

      [ func(C1),      C2 ,       C3 ],
      [      C1 , func(C2),       C3 ],
      [ func(C1), func(C2),       C3 ],
      [      C1 ,      C2 ,  func(C3)],
      .. etc

    This is effectively treating the list of constraints as a bitmask of width len(lst) and counting up, skipping the
    0th element (unmodified array).

    The code below yields lists of constraints permuted as above by treating list indeces as bitmasks from 1 to
     2**len(lst) and applying func to all the set bit offsets.

    '''
    for i in range(1, 2**len(lst)):
        yield [func(item) if (1<<j)&i else item for (j, item) in enumerate(lst)]


Instruction:
How would you explain what the following Python 3 function does
def input_from_cons(constupl, datas):
    ' solve bytes in |datas| based on '
    def make_chr(c):
        try:
            return chr(c)
        except Exception:
            return c
    newset = constraints_to_constraintset(constupl)

    ret = ''
    for data in datas:
        for c in data:
            ret += make_chr(solver.get_value(newset, c))
    return ret

Response: solve bytes in |datas| based on '


Instruction:
Write a Python 3 function for
executing a symbolic run that follows a concrete run ; return constraints generated and the stdin data produced

Response:
def symbolic_run_get_cons(trace):
    '''
    Execute a symbolic run that follows a concrete run; return constraints generated
    and the stdin data produced
    '''

    m2 = Manticore.linux(prog, workspace_url='mem:')
    f = Follower(trace)
    m2.verbosity(VERBOSITY)
    m2.register_plugin(f)

    def on_term_testcase(mcore, state, stateid, err):
        with m2.locked_context() as ctx:
            readdata = []
            for name, fd, data in state.platform.syscall_trace:
                if name in ('_receive', '_read') and fd == 0:
                    readdata.append(data)
            ctx['readdata'] = readdata
            ctx['constraints'] = list(state.constraints.constraints)

    m2.subscribe('will_terminate_state', on_term_testcase)

    m2.run()

    constraints = m2.context['constraints']
    datas = m2.context['readdata']

    return constraints, datas


Instruction:
Implement a function in Python 3 to
move the file to the specified offset according to whence.

Response:
def seek(self, offset, whence=os.SEEK_SET):
        """
        Repositions the file C{offset} according to C{whence}.
        Returns the resulting offset or -1 in case of error.
        :rtype: int
        :return: the file offset.
        """
        assert isinstance(offset, int)
        assert whence in (os.SEEK_SET, os.SEEK_CUR, os.SEEK_END)

        new_position = 0
        if whence == os.SEEK_SET:
            new_position = offset
        elif whence == os.SEEK_CUR:
            new_position = self.pos + offset
        elif whence == os.SEEK_END:
            new_position = self.max_size + offset

        if new_position < 0:
            return -1

        self.pos = new_position

        return self.pos


Instruction:
Implement a Python 3 function for
reading up to count bytes from the file.

Response:
def read(self, count):
        """
        Reads up to C{count} bytes from the file.
        :rtype: list
        :return: the list of symbolic bytes read
        """
        if self.pos > self.max_size:
            return []
        else:
            size = min(count, self.max_size - self.pos)
            ret = [self.array[i] for i in range(self.pos, self.pos + size)]
            self.pos += size
            return ret


Instruction:
Given the following Python 3 function, write the documentation
def write(self, data):
        size = min(len(data), self.max_size - self.pos)
        for i in range(self.pos, self.pos + size):
            self.array[i] = data[i - self.pos]

Response: Writes the symbolic bytes in data onto the file.


Instruction:
Write a Python 3 script to
create a new Linux object with an empty CPU and standard file set.

Response:
def empty_platform(cls, arch):
        """
        Create a platform without an ELF loaded.

        :param str arch: The architecture of the new platform
        :rtype: Linux
        """
        platform = cls(None)
        platform._init_cpu(arch)
        platform._init_std_fds()
        return platform


Instruction:
How would you code a function in Python 3 to
load and establish program state.

Response:
def _execve(self, program, argv, envp):
        """
        Load `program` and establish program state, such as stack and arguments.

        :param program str: The ELF binary to load
        :param argv list: argv array
        :param envp list: envp array
        """
        argv = [] if argv is None else argv
        envp = [] if envp is None else envp

        logger.debug(f"Loading {program} as a {self.arch} elf")

        self.load(program, envp)
        self._arch_specific_init()

        self._stack_top = self.current.STACK
        self.setup_stack([program] + argv, envp)

        nprocs = len(self.procs)
        nfiles = len(self.files)
        assert nprocs > 0
        self.running = list(range(nprocs))

        # Each process can wait for one timeout
        self.timers = [None] * nprocs
        # each fd has a waitlist
        self.rwait = [set() for _ in range(nfiles)]
        self.twait = [set() for _ in range(nfiles)]

        # Install event forwarders
        for proc in self.procs:
            self.forward_events_from(proc)


Instruction:
How would you code a function in Python 3 to
initialize the ARM kernel helpers for the current ARM kernel.

Response:
def _init_arm_kernel_helpers(self):
        """
        ARM kernel helpers

        https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt
        """

        page_data = bytearray(b'\xf1\xde\xfd\xe7' * 1024)

        # Extracted from a RPi2
        preamble = binascii.unhexlify(
            'ff0300ea' +
            '650400ea' +
            'f0ff9fe5' +
            '430400ea' +
            '220400ea' +
            '810400ea' +
            '000400ea' +
            '870400ea'
        )

        # XXX(yan): The following implementations of cmpxchg and cmpxchg64 were
        # handwritten to not use any exclusive instructions (e.g. ldrexd) or
        # locking. For actual implementations, refer to
        # arch/arm64/kernel/kuser32.S in the Linux source code.
        __kuser_cmpxchg64 = binascii.unhexlify(
            '30002de9' +  # push    {r4, r5}
            '08c09de5' +  # ldr     ip, [sp, #8]
            '30009ce8' +  # ldm     ip, {r4, r5}
            '010055e1' +  # cmp     r5, r1
            '00005401' +  # cmpeq   r4, r0
            '0100a013' +  # movne   r0, #1
            '0000a003' +  # moveq   r0, #0
            '0c008c08' +  # stmeq   ip, {r2, r3}
            '3000bde8' +  # pop     {r4, r5}
            '1eff2fe1'   # bx      lr
        )

        __kuser_dmb = binascii.unhexlify(
            '5bf07ff5' +  # dmb ish
            '1eff2fe1'   # bx lr
        )

        __kuser_cmpxchg = binascii.unhexlify(
            '003092e5' +  # ldr     r3, [r2]
            '000053e1' +  # cmp     r3, r0
            '0000a003' +  # moveq   r0, #0
            '00108205' +  # streq   r1, [r2]
            '0100a013' +  # movne   r0, #1
            '1eff2fe1'   # bx      lr
        )

        # Map a TLS segment
        self._arm_tls_memory = self.current.memory.mmap(None, 4, 'rw ')

        __kuser_get_tls = binascii.unhexlify(
            '04009FE5' +  # ldr r0, [pc, #4]
            '010090e8' +  # ldm r0, {r0}
            '1eff2fe1'   # bx lr
        ) + struct.pack('<I', self._arm_tls_memory)

        tls_area = b'\x00' * 12

        version = struct.pack('<I', 5)

        def update(address, code):
            page_data[address:address + len(code)] = code

        # Offsets from Documentation/arm/kernel_user_helpers.txt in Linux
        update(0x000, preamble)
        update(0xf60, __kuser_cmpxchg64)
        update(0xfa0, __kuser_dmb)
        update(0xfc0, __kuser_cmpxchg)
        update(0xfe0, __kuser_get_tls)
        update(0xff0, tls_area)
        update(0xffc, version)

        self.current.memory.mmap(0xffff0000, len(page_data), 'r x', page_data)


Instruction:
Here you have a function in Python 3, explain what it does
def setup_stack(self, argv, envp):
        cpu = self.current

        # In case setup_stack() is called again, we make sure we're growing the
        # stack from the original top
        cpu.STACK = self._stack_top

        auxv = self.auxv
        logger.debug("Setting argv, envp and auxv.")
        logger.debug(f"\tArguments: {argv!r}")
        if envp:
            logger.debug("\tEnvironment:")
            for e in envp:
                logger.debug(f"\t\t{e!r}")

        logger.debug("\tAuxv:")
        for name, val in auxv.items():
            logger.debug(f"\t\t{name}: 0x{val:x}")

        # We save the argument and environment pointers
        argvlst = []
        envplst = []

        # end envp marker empty string
        for evar in envp:
            cpu.push_bytes('\x00')
            envplst.append(cpu.push_bytes(evar))

        for arg in argv:
            cpu.push_bytes('\x00')
            argvlst.append(cpu.push_bytes(arg))

        # Put all auxv strings into the string stack area.
        # And replace the value be its pointer

        for name, value in auxv.items():
            if hasattr(value, '__len__'):
                cpu.push_bytes(value)
                auxv[name] = cpu.STACK

        # The "secure execution" mode of secure_getenv() is controlled by the
        # AT_SECURE flag contained in the auxiliary vector passed from the
        # kernel to user space.
        auxvnames = {
            'AT_IGNORE': 1,  # Entry should be ignored
            'AT_EXECFD': 2,  # File descriptor of program
            'AT_PHDR': 3,  # Program headers for program
            'AT_PHENT': 4,  # Size of program header entry
            'AT_PHNUM': 5,  # Number of program headers
            'AT_PAGESZ': 6,  # System page size
            'AT_BASE': 7,  # Base address of interpreter
            'AT_FLAGS': 8,  # Flags
            'AT_ENTRY': 9,  # Entry point of program
            'AT_NOTELF': 10,  # Program is not ELF
            'AT_UID': 11,  # Real uid
            'AT_EUID': 12,  # Effective uid
            'AT_GID': 13,  # Real gid
            'AT_EGID': 14,  # Effective gid
            'AT_CLKTCK': 17,  # Frequency of times()
            'AT_PLATFORM': 15,  # String identifying platform.
            'AT_HWCAP': 16,  # Machine-dependent hints about processor capabilities.
            'AT_FPUCW': 18,  # Used FPU control word.
            'AT_SECURE': 23,  # Boolean, was exec setuid-like?
            'AT_BASE_PLATFORM': 24,  # String identifying real platforms.
            'AT_RANDOM': 25,  # Address of 16 random bytes.
            'AT_EXECFN': 31,  # Filename of executable.
            'AT_SYSINFO': 32,  # Pointer to the global system page used for system calls and other nice things.
            'AT_SYSINFO_EHDR': 33,  # Pointer to the global system page used for system calls and other nice things.
        }
        # AT_NULL
        cpu.push_int(0)
        cpu.push_int(0)
        for name, val in auxv.items():
            cpu.push_int(val)
            cpu.push_int(auxvnames[name])

        # NULL ENVP
        cpu.push_int(0)
        for var in reversed(envplst):              # ENVP n
            cpu.push_int(var)
        envp = cpu.STACK

        # NULL ARGV
        cpu.push_int(0)
        for arg in reversed(argvlst):              # Argv n
            cpu.push_int(arg)
        argv = cpu.STACK

        # ARGC
        cpu.push_int(len(argvlst))

Response: This function is called by the parser to set up the stack.


Instruction:
Write a Python 3 function that can
load and prepares an ELF program in memory and prepares the initial CPU state.

Response:
def load(self, filename, env):
        """
        Loads and an ELF program in memory and prepares the initial CPU state.
        Creates the stack and loads the environment variables and the arguments in it.

        :param filename: pathname of the file to be executed. (used for auxv)
        :param list env: A list of env variables. (used for extracting vars that control ld behavior)
        :raises error:
            - 'Not matching cpu': if the program is compiled for a different architecture
            - 'Not matching memory': if the program is compiled for a different address size
        :todo: define va_randomize and read_implies_exec personality
        """
        # load elf See binfmt_elf.c
        # read the ELF object file
        cpu = self.current
        elf = self.elf
        arch = self.arch
        env = dict(var.split('=') for var in env if '=' in var)
        addressbitsize = {'x86': 32, 'x64': 64, 'ARM': 32}[elf.get_machine_arch()]
        logger.debug("Loading %s as a %s elf", filename, arch)

        assert elf.header.e_type in ['ET_DYN', 'ET_EXEC', 'ET_CORE']

        # Get interpreter elf
        interpreter = None
        for elf_segment in elf.iter_segments():
            if elf_segment.header.p_type != 'PT_INTERP':
                continue
            interpreter_filename = elf_segment.data()[:-1]
            logger.info(f'Interpreter filename: {interpreter_filename}')
            if os.path.exists(interpreter_filename.decode('utf-8')):
                interpreter = ELFFile(open(interpreter_filename, 'rb'))
            elif 'LD_LIBRARY_PATH' in env:
                for mpath in env['LD_LIBRARY_PATH'].split(":"):
                    interpreter_path_filename = os.path.join(mpath, os.path.basename(interpreter_filename))
                    logger.info(f"looking for interpreter {interpreter_path_filename}")
                    if os.path.exists(interpreter_path_filename):
                        interpreter = ELFFile(open(interpreter_path_filename, 'rb'))
                        break
            break
        if interpreter is not None:
            assert interpreter.get_machine_arch() == elf.get_machine_arch()
            assert interpreter.header.e_type in ['ET_DYN', 'ET_EXEC']

        # Stack Executability
        executable_stack = False
        for elf_segment in elf.iter_segments():
            if elf_segment.header.p_type != 'PT_GNU_STACK':
                continue
            if elf_segment.header.p_flags & 0x01:
                executable_stack = True
            else:
                executable_stack = False
            break

        base = 0
        elf_bss = 0
        end_code = 0
        end_data = 0
        elf_brk = 0
        self.load_addr = 0

        for elf_segment in elf.iter_segments():
            if elf_segment.header.p_type != 'PT_LOAD':
                continue

            align = 0x1000  # elf_segment.header.p_align

            ELF_PAGEOFFSET = elf_segment.header.p_vaddr & (align - 1)

            flags = elf_segment.header.p_flags
            memsz = elf_segment.header.p_memsz + ELF_PAGEOFFSET
            offset = elf_segment.header.p_offset - ELF_PAGEOFFSET
            filesz = elf_segment.header.p_filesz + ELF_PAGEOFFSET
            vaddr = elf_segment.header.p_vaddr - ELF_PAGEOFFSET
            memsz = cpu.memory._ceil(memsz)
            if base == 0 and elf.header.e_type == 'ET_DYN':
                assert vaddr == 0
                if addressbitsize == 32:
                    base = 0x56555000
                else:
                    base = 0x555555554000

            perms = perms_from_elf(flags)
            hint = base + vaddr
            if hint == 0:
                hint = None

            logger.debug(f"Loading elf offset: {offset:08x} addr:{base + vaddr:08x} {base + vaddr + memsz:08x} {perms}")
            base = cpu.memory.mmapFile(hint, memsz, perms, elf_segment.stream.name, offset) - vaddr

            if self.load_addr == 0:
                self.load_addr = base + vaddr

            k = base + vaddr + filesz
            if k > elf_bss:
                elf_bss = k
            if (flags & 4) and end_code < k:  # PF_X
                end_code = k
            if end_data < k:
                end_data = k
            k = base + vaddr + memsz
            if k > elf_brk:
                elf_brk = k

        elf_entry = elf.header.e_entry
        if elf.header.e_type == 'ET_DYN':
            elf_entry += self.load_addr
        entry = elf_entry
        real_elf_brk = elf_brk

        # We need to explicitly clear bss, as fractional pages will have data from the file
        bytes_to_clear = elf_brk - elf_bss
        if bytes_to_clear > 0:
            logger.debug(f"Zeroing main elf fractional pages. From bss({elf_bss:x}) to brk({elf_brk:x}), {bytes_to_clear} bytes.")
            cpu.write_bytes(elf_bss, '\x00' * bytes_to_clear, force=True)

        stack_size = 0x21000

        if addressbitsize == 32:
            stack_top = 0xc0000000
        else:
            stack_top = 0x800000000000
        stack_base = stack_top - stack_size
        stack = cpu.memory.mmap(stack_base, stack_size, 'rwx', name='stack') + stack_size
        assert stack_top == stack

        reserved = cpu.memory.mmap(base + vaddr + memsz, 0x1000000, '   ')
        interpreter_base = 0
        if interpreter is not None:
            base = 0
            elf_bss = 0
            end_code = 0
            end_data = 0
            elf_brk = 0
            entry = interpreter.header.e_entry
            for elf_segment in interpreter.iter_segments():
                if elf_segment.header.p_type != 'PT_LOAD':
                    continue
                align = 0x1000  # elf_segment.header.p_align
                vaddr = elf_segment.header.p_vaddr
                filesz = elf_segment.header.p_filesz
                flags = elf_segment.header.p_flags
                offset = elf_segment.header.p_offset
                memsz = elf_segment.header.p_memsz

                ELF_PAGEOFFSET = (vaddr & (align - 1))
                memsz = memsz + ELF_PAGEOFFSET
                offset = offset - ELF_PAGEOFFSET
                filesz = filesz + ELF_PAGEOFFSET
                vaddr = vaddr - ELF_PAGEOFFSET
                memsz = cpu.memory._ceil(memsz)

                if base == 0 and interpreter.header.e_type == 'ET_DYN':
                    assert vaddr == 0
                    total_size = self._interp_total_size(interpreter)
                    base = stack_base - total_size

                if base == 0:
                    assert vaddr == 0
                perms = perms_from_elf(flags)
                hint = base + vaddr
                if hint == 0:
                    hint = None

                base = cpu.memory.mmapFile(hint, memsz, perms, elf_segment.stream.name, offset)
                base -= vaddr
                logger.debug(
                    f"Loading interpreter offset: {offset:08x} "
                    f"addr:{base + vaddr:08x} "
                    f"{base + vaddr + memsz:08x} "
                    f"{(flags & 1 and 'r' or ' ')}"
                    f"{(flags & 2 and 'w' or ' ')}"
                    f"{(flags & 4 and 'x' or ' ')}"
                )

                k = base + vaddr + filesz
                if k > elf_bss:
                    elf_bss = k
                if (flags & 4) and end_code < k:  # PF_X
                    end_code = k
                if end_data < k:
                    end_data = k
                k = base + vaddr + memsz
                if k > elf_brk:
                    elf_brk = k

            if interpreter.header.e_type == 'ET_DYN':
                entry += base
            interpreter_base = base

            bytes_to_clear = elf_brk - elf_bss
            if bytes_to_clear > 0:
                logger.debug(f"Zeroing interpreter elf fractional pages. From bss({elf_bss:x}) to brk({elf_brk:x}), {bytes_to_clear} bytes.")
                cpu.write_bytes(elf_bss, '\x00' * bytes_to_clear, force=True)

        # free reserved brk space
        cpu.memory.munmap(reserved, 0x1000000)

        # load vdso
        #vdso_addr = load_vdso(addressbitsize)

        cpu.STACK = stack
        cpu.PC = entry

        logger.debug(f"Entry point: {entry:016x}")
        logger.debug(f"Stack start: {stack:016x}")
        logger.debug(f"Brk: {real_elf_brk:016x}")
        logger.debug(f"Mappings:")
        for m in str(cpu.memory).split('\n'):
            logger.debug(f"  {m}")
        self.base = base
        self.elf_bss = elf_bss
        self.end_code = end_code
        self.end_data = end_data
        self.elf_brk = real_elf_brk
        self.brk = real_elf_brk

        at_random = cpu.push_bytes('A' * 16)
        at_execfn = cpu.push_bytes(f'{filename}\x00')

        self.auxv = {
            'AT_PHDR': self.load_addr + elf.header.e_phoff,  # Program headers for program
            'AT_PHENT': elf.header.e_phentsize,       # Size of program header entry
            'AT_PHNUM': elf.header.e_phnum,           # Number of program headers
            'AT_PAGESZ': cpu.memory.page_size,         # System page size
            'AT_BASE': interpreter_base,             # Base address of interpreter
            'AT_FLAGS': elf.header.e_flags,           # Flags
            'AT_ENTRY': elf_entry,                    # Entry point of program
            'AT_UID': 1000,                         # Real uid
            'AT_EUID': 1000,                         # Effective uid
            'AT_GID': 1000,                         # Real gid
            'AT_EGID': 1000,                         # Effective gid
            'AT_CLKTCK': 100,                          # Frequency of times()
            'AT_HWCAP': 0,                            # Machine-dependent hints about processor capabilities.
            'AT_RANDOM': at_random,                    # Address of 16 random bytes.
            'AT_EXECFN': at_execfn,                    # Filename of executable.
        }


Instruction:
Implement a Python 3 function for
adding a file descriptor to the current file descriptor list. Returns the index of the file descriptor in the file descr.

Response:
def _open(self, f):
        """
        Adds a file descriptor to the current file descriptor list

        :rtype: int
        :param f: the file descriptor to add.
        :return: the index of the file descriptor in the file descr. list
        """
        if None in self.files:
            fd = self.files.index(None)
            self.files[fd] = f
        else:
            fd = len(self.files)
            self.files.append(f)
        return fd


Instruction:
How would you code a function in Python 3 to
close a file descriptor.

Response:
def _close(self, fd):
        """
        Removes a file descriptor from the file descriptor list
        :rtype: int
        :param fd: the file descriptor to close.
        :return: C{0} on success.
        """
        try:
            self.files[fd].close()
            self._closed_files.append(self.files[fd])  # Keep track for SymbolicFile testcase generation
            self.files[fd] = None
        except IndexError:
            raise FdError(f"Bad file descriptor ({fd})")


Instruction:
Given the following Python 3 function, write the documentation
def _is_fd_open(self, fd):
        return fd >= 0 and fd < len(self.files) and self.files[fd] is not None

Response: Determines if the file descriptor is open.


Instruction:
Explain what the following Python 3 code does
def sys_chdir(self, path):
        path_str = self.current.read_string(path)
        logger.debug(f"chdir({path_str})")
        try:
            os.chdir(path_str)
            return 0
        except OSError as e:
            return e.errno

Response: Change current working directory


Instruction:
Given the following Python 3 function, write the documentation
def sys_getcwd(self, buf, size):

        try:
            current_dir = os.getcwd()
            length = len(current_dir) + 1

            if size > 0 and size < length:
                logger.info("GETCWD: size is greater than 0, but is smaller than the length"
                            "of the path + 1. Returning ERANGE")
                return -errno.ERANGE

            if not self.current.memory.access_ok(slice(buf, buf + length), 'w'):
                logger.info("GETCWD: buf within invalid memory. Returning EFAULT")
                return -errno.EFAULT

            self.current.write_string(buf, current_dir)
            logger.debug(f"getcwd(0x{buf:08x}, {size}) -> <{current_dir}> (Size {length})")
            return length

        except OSError as e:
            return -e.errno

Response: Get the current working directory and return the size of the array.


Instruction:
Write a Python 3 function that can
write - send bytes through a file descriptor The write system call writes up to count bytes from the buffer pointed to by buf to the file descriptor fd. If count is zero, write returns 0 and optionally sets *tx_bytes to zero. :param fd a valid file descriptor :param buf a memory buffer :param count number of bytes to send :return: 0 Success EBADF fd is not a valid file descriptor or is not open. EFAULT buf or tx_bytes points to an invalid address.

Response:
def sys_write(self, fd, buf, count):
        """ write - send bytes through a file descriptor
          The write system call writes up to count bytes from the buffer pointed
          to by buf to the file descriptor fd. If count is zero, write returns 0
          and optionally sets *tx_bytes to zero.

          :param fd            a valid file descriptor
          :param buf           a memory buffer
          :param count         number of bytes to send
          :return: 0          Success
                    EBADF      fd is not a valid file descriptor or is not open.
                    EFAULT     buf or tx_bytes points to an invalid address.
        """
        data: bytes = bytes()
        cpu = self.current
        if count != 0:
            try:
                write_fd = self._get_fd(fd)
            except FdError as e:
                logger.error(f"WRITE: Not valid file descriptor ({fd}). Returning -{e.err}")
                return -e.err

            # TODO check count bytes from buf
            if buf not in cpu.memory or buf + count not in cpu.memory:
                logger.debug("WRITE: buf points to invalid address. Returning EFAULT")
                return -errno.EFAULT

            if fd > 2 and write_fd.is_full():
                cpu.PC -= cpu.instruction.size
                self.wait([], [fd], None)
                raise RestartSyscall()

            data: MixedSymbolicBuffer = cpu.read_bytes(buf, count)
            data: bytes = self._transform_write_data(data)
            write_fd.write(data)

            for line in data.split(b'\n'):
                line = line.decode('latin-1')  # latin-1 encoding will happily decode any byte (0x00-0xff)
                logger.debug(f"WRITE({fd}, 0x{buf:08x}, {count}) -> <{repr(line):48s}>")
            self.syscall_trace.append(("_write", fd, data))
            self.signal_transmit(fd)

        return len(data)


Instruction:
Here you have a function in Python 3, explain what it does
def sys_access(self, buf, mode):
        filename = b''
        for i in range(0, 255):
            c = Operators.CHR(self.current.read_int(buf + i, 8))
            if c == b'\x00':
                break
            filename += c

        if os.access(filename, mode):
            return 0
        else:
            return -1

Response: Checks real user s permissions for a file.


Instruction:
Given the following Python 3 function, write the documentation
def sys_newuname(self, old_utsname):
        from datetime import datetime

        def pad(s):
            return s + '\x00' * (65 - len(s))

        now = datetime(2017, 8, 0o1).strftime("%a %b %d %H:%M:%S ART %Y")
        info = (('sysname', 'Linux'),
                ('nodename', 'ubuntu'),
                ('release', '4.4.0-77-generic'),
                ('version', '#98 SMP ' + now),
                ('machine', self._uname_machine),
                ('domainname', ''))

        uname_buf = ''.join(pad(pair[1]) for pair in info)
        self.current.write_bytes(old_utsname, uname_buf)
        return 0

Response: Writes system information in the variable old_utsname.


Instruction:
Write a Python 3 function that can
change data segment size (moves the C{brk} to the new address) :rtype: int :param brk: the new address for C{brk}. :return: the value of the new C{brk}. :raises error: - "Error in brk!" if there is any error allocating the memory

Response:
def sys_brk(self, brk):
        """
        Changes data segment size (moves the C{brk} to the new address)
        :rtype: int
        :param brk: the new address for C{brk}.
        :return: the value of the new C{brk}.
        :raises error:
                    - "Error in brk!" if there is any error allocating the memory
        """
        if brk != 0 and brk > self.elf_brk:
            mem = self.current.memory
            size = brk - self.brk
            if brk > mem._ceil(self.brk):
                perms = mem.perms(self.brk - 1)
                addr = mem.mmap(mem._ceil(self.brk), size, perms)
                if not mem._ceil(self.brk) == addr:
                    logger.error(f"Error in brk: ceil: {hex(mem._ceil(self.brk))} brk: {hex(brk)} self.brk: {hex(self.brk)} addr: {hex(addr)}")
                    return self.brk
            self.brk += size
        return self.brk


Instruction:
Make a summary of the following Python 3 code
def sys_arch_prctl(self, code, addr):
        ARCH_SET_GS = 0x1001
        ARCH_SET_FS = 0x1002
        ARCH_GET_FS = 0x1003
        ARCH_GET_GS = 0x1004
        if code not in {ARCH_SET_GS, ARCH_SET_FS, ARCH_GET_FS, ARCH_GET_GS}:
            logger.debug("code not in expected options ARCH_GET/SET_FS/GS")
            return -errno.EINVAL
        if code != ARCH_SET_FS:
            raise NotImplementedError("Manticore supports only arch_prctl with code=ARCH_SET_FS (0x1002) for now")
        self.current.FS = 0x63
        self.current.set_descriptor(self.current.FS, addr, 0x4000, 'rw')
        return 0

Response: Sets the architecture - specific thread state.


Instruction:
Here you have a function in Python 3, explain what it does
def sys_open(self, buf, flags, mode):
        filename = self.current.read_string(buf)
        try:
            f = self._sys_open_get_file(filename, flags)
            logger.debug(f"Opening file {filename} for real fd {f.fileno()}")
        except IOError as e:
            logger.warning(f"Could not open file {filename}. Reason: {e!s}")
            return -e.errno if e.errno is not None else -errno.EINVAL

        return self._open(f)

Response: Open a file and return its handle.


Instruction:
Here you have a function in Python 3, explain what it does
def sys_openat(self, dirfd, buf, flags, mode):

        filename = self.current.read_string(buf)
        dirfd = ctypes.c_int32(dirfd).value

        if os.path.isabs(filename) or dirfd == self.FCNTL_FDCWD:
            return self.sys_open(buf, flags, mode)

        try:
            dir_entry = self._get_fd(dirfd)
        except FdError as e:
            logger.info("openat: Not valid file descriptor. Returning EBADF")
            return -e.err

        if not isinstance(dir_entry, Directory):
            logger.info("openat: Not directory descriptor. Returning ENOTDIR")
            return -errno.ENOTDIR

        dir_path = dir_entry.name

        filename = os.path.join(dir_path, filename)
        try:
            f = self._sys_open_get_file(filename, flags)
            logger.debug(f"Opening file {filename} for real fd {f.fileno()}")
        except IOError as e:
            logger.info(f"Could not open file {filename}. Reason: {e!s}")
            return -e.errno if e.errno is not None else -errno.EINVAL

        return self._open(f)

Response: Openat SystemCall - Similar to sys. open but uses the same arguments as sys. open but uses the same arguments as sys. open but uses the same arguments as sys. open but uses the same arguments as sys. open.


Instruction:
Write a Python 3 function that can
rename filename oldnamep to newnamep.

Response:
def sys_rename(self, oldnamep, newnamep):
        """
        Rename filename `oldnamep` to `newnamep`.

        :param int oldnamep: pointer to oldname
        :param int newnamep: pointer to newname
        """
        oldname = self.current.read_string(oldnamep)
        newname = self.current.read_string(newnamep)

        ret = 0
        try:
            os.rename(oldname, newname)
        except OSError as e:
            ret = -e.errno

        return ret


Instruction:
Create a Python 3 function for
synchronizing a file s in - core state with that on disk.

Response:
def sys_fsync(self, fd):
        """
        Synchronize a file's in-core state with that on disk.
        """

        ret = 0
        try:
            self.files[fd].sync()
        except IndexError:
            ret = -errno.EBADF
        except FdError:
            ret = -errno.EINVAL

        return ret


Instruction:
Can you generate a brief explanation for the following Python 3 code
def sys_dup(self, fd):

        if not self._is_fd_open(fd):
            logger.info("DUP: Passed fd is not open. Returning EBADF")
            return -errno.EBADF

        newfd = self._dup(fd)
        return newfd

Response: Duplicate an open file descriptor.


Instruction:
How would you implement a function in Python 3 that
duplicates a file descriptor to a newfd.

Response:
def sys_dup2(self, fd, newfd):
        """
        Duplicates an open fd to newfd. If newfd is open, it is first closed
        :rtype: int
        :param fd: the open file descriptor to duplicate.
        :param newfd: the file descriptor to alias the file described by fd.
        :return: newfd.
        """
        try:
            file = self._get_fd(fd)
        except FdError as e:
            logger.info("DUP2: Passed fd is not open. Returning EBADF")
            return -e.err

        soft_max, hard_max = self._rlimits[self.RLIMIT_NOFILE]
        if newfd >= soft_max:
            logger.info("DUP2: newfd is above max descriptor table size")
            return -errno.EBADF

        if self._is_fd_open(newfd):
            self._close(newfd)

        if newfd >= len(self.files):
            self.files.extend([None] * (newfd + 1 - len(self.files)))

        self.files[newfd] = self.files[fd]

        logger.debug('sys_dup2(%d,%d) -> %d', fd, newfd, newfd)
        return newfd