import ctypes
import errno
import io
import threading
import socket
import traceback
from lldbsuite.support import seven
def checksum(message):
"""
Calculate the GDB server protocol checksum of the message.
The GDB server protocol uses a simple modulo 256 sum.
"""
check = 0
for c in message:
check += ord(c)
return check % 256
def frame_packet(message):
"""
Create a framed packet that's ready to send over the GDB connection
channel.
Framing includes surrounding the message between $ and #, and appending
a two character hex checksum.
"""
return "$%s#%02x" % (message, checksum(message))
def escape_binary(message):
"""
Escape the binary message using the process described in the GDB server
protocol documentation.
Most bytes are sent through as-is, but $, #, and { are escaped by writing
a { followed by the original byte mod 0x20.
"""
out = ""
for c in message:
d = ord(c)
if d in (0x23, 0x24, 0x7D):
out += chr(0x7D)
out += chr(d ^ 0x20)
else:
out += c
return out
def hex_encode_bytes(message):
"""
Encode the binary message by converting each byte into a two-character
hex string.
"""
out = ""
for c in message:
out += "%02x" % ord(c)
return out
def hex_decode_bytes(hex_bytes):
"""
Decode the hex string into a binary message by converting each two-character
hex string into a single output byte.
"""
out = ""
hex_len = len(hex_bytes)
i = 0
while i < hex_len - 1:
out += chr(int(hex_bytes[i : i + 2], 16))
i += 2
return out
class MockGDBServerResponder:
"""
A base class for handling client packets and issuing server responses for
GDB tests.
This handles many typical situations, while still allowing subclasses to
completely customize their responses.
Most subclasses will be interested in overriding the other() method, which
handles any packet not recognized in the common packet handling code.
"""
registerCount = 40
packetLog = None
class RESPONSE_DISCONNECT:
pass
def __init__(self):
self.packetLog = []
def respond(self, packet):
"""
Return the unframed packet data that the server should issue in response
to the given packet received from the client.
"""
self.packetLog.append(packet)
if packet is MockGDBServer.PACKET_INTERRUPT:
return self.interrupt()
if packet == "c":
return self.cont()
if packet.startswith("vCont;c"):
return self.vCont(packet)
if packet[0] == "A":
return self.A(packet)
if packet[0] == "D":
return self.D(packet)
if packet[0] == "g":
return self.readRegisters()
if packet[0] == "G":
# Gxxxxxxxxxxx
# Gxxxxxxxxxxx;thread:1234;
return self.writeRegisters(packet[1:].split(";")[0])
if packet[0] == "p":
regnum = packet[1:].split(";")[0]
return self.readRegister(int(regnum, 16))
if packet[0] == "P":
register, value = packet[1:].split("=")
return self.writeRegister(int(register, 16), value)
if packet[0] == "m":
addr, length = [int(x, 16) for x in packet[1:].split(",")]
return self.readMemory(addr, length)
if packet[0] == "M":
location, encoded_data = packet[1:].split(":")
addr, length = [int(x, 16) for x in location.split(",")]
return self.writeMemory(addr, encoded_data)
if packet[0:7] == "qSymbol":
return self.qSymbol(packet[8:])
if packet[0:10] == "qSupported":
return self.qSupported(packet[11:].split(";"))
if packet == "qfThreadInfo":
return self.qfThreadInfo()
if packet == "qsThreadInfo":
return self.qsThreadInfo()
if packet == "qC":
return self.qC()
if packet == "QEnableErrorStrings":
return self.QEnableErrorStrings()
if packet == "?":
return self.haltReason()
if packet == "s":
return self.haltReason()
if packet[0] == "H":
tid = packet[2:]
if "." in tid:
assert tid.startswith("p")
# TODO: do we want to do anything with PID?
tid = tid.split(".", 1)[1]
return self.selectThread(packet[1], int(tid, 16))
if packet[0:6] == "qXfer:":
obj, read, annex, location = packet[6:].split(":")
offset, length = [int(x, 16) for x in location.split(",")]
data, has_more = self.qXferRead(obj, annex, offset, length)
if data is not None:
return self._qXferResponse(data, has_more)
return ""
if packet.startswith("vAttach;"):
pid = packet.partition(";")[2]
return self.vAttach(int(pid, 16))
if packet[0] == "Z":
return self.setBreakpoint(packet)
if packet.startswith("qThreadStopInfo"):
threadnum = int(packet[15:], 16)
return self.threadStopInfo(threadnum)
if packet == "QThreadSuffixSupported":
return self.QThreadSuffixSupported()
if packet == "QListThreadsInStopReply":
return self.QListThreadsInStopReply()
if packet.startswith("qMemoryRegionInfo:"):
return self.qMemoryRegionInfo(int(packet.split(":")[1], 16))
if packet == "qQueryGDBServer":
return self.qQueryGDBServer()
if packet == "qHostInfo":
return self.qHostInfo()
if packet == "qGetWorkingDir":
return self.qGetWorkingDir()
if packet == "qOffsets":
return self.qOffsets()
if packet == "qProcessInfo":
return self.qProcessInfo()
if packet == "qsProcessInfo":
return self.qsProcessInfo()
if packet.startswith("qfProcessInfo"):
return self.qfProcessInfo(packet)
if packet.startswith("jGetLoadedDynamicLibrariesInfos"):
return self.jGetLoadedDynamicLibrariesInfos(packet)
if packet.startswith("qPathComplete:"):
return self.qPathComplete()
if packet.startswith("vFile:"):
return self.vFile(packet)
if packet.startswith("vRun;"):
return self.vRun(packet)
if packet.startswith("qLaunchGDBServer;"):
_, host = packet.partition(";")[2].split(":")
return self.qLaunchGDBServer(host)
if packet.startswith("qLaunchSuccess"):
return self.qLaunchSuccess()
if packet.startswith("QEnvironment:"):
return self.QEnvironment(packet)
if packet.startswith("QEnvironmentHexEncoded:"):
return self.QEnvironmentHexEncoded(packet)
if packet.startswith("qRegisterInfo"):
regnum = int(packet[len("qRegisterInfo") :], 16)
return self.qRegisterInfo(regnum)
if packet == "k":
return self.k()
return self.other(packet)
def qsProcessInfo(self):
return "E04"
def qfProcessInfo(self, packet):
return "E04"
def jGetLoadedDynamicLibrariesInfos(self, packet):
return ""
def qGetWorkingDir(self):
return "2f"
def qOffsets(self):
return ""
def qProcessInfo(self):
return ""
def qHostInfo(self):
return "ptrsize:8;endian:little;"
def qQueryGDBServer(self):
return "E04"
def interrupt(self):
raise self.UnexpectedPacketException()
def cont(self):
raise self.UnexpectedPacketException()
def vCont(self, packet):
raise self.UnexpectedPacketException()
def A(self, packet):
return ""
def D(self, packet):
return "OK"
def readRegisters(self):
return "00000000" * self.registerCount
def readRegister(self, register):
return "00000000"
def writeRegisters(self, registers_hex):
return "OK"
def writeRegister(self, register, value_hex):
return "OK"
def readMemory(self, addr, length):
return "00" * length
def writeMemory(self, addr, data_hex):
return "OK"
def qSymbol(self, symbol_args):
return "OK"
def qSupported(self, client_supported):
return "qXfer:features:read+;PacketSize=3fff;QStartNoAckMode+"
def qfThreadInfo(self):
return "l"
def qsThreadInfo(self):
return "l"
def qC(self):
return "QC0"
def QEnableErrorStrings(self):
return "OK"
def haltReason(self):
# SIGINT is 2, return type is 2 digit hex string
return "S02"
def qXferRead(self, obj, annex, offset, length):
return None, False
def _qXferResponse(self, data, has_more):
return "%s%s" % ("m" if has_more else "l", escape_binary(data))
def vAttach(self, pid):
raise self.UnexpectedPacketException()
def selectThread(self, op, thread_id):
return "OK"
def setBreakpoint(self, packet):
raise self.UnexpectedPacketException()
def threadStopInfo(self, threadnum):
return ""
def other(self, packet):
# empty string means unsupported
return ""
def QThreadSuffixSupported(self):
return ""
def QListThreadsInStopReply(self):
return ""
def qMemoryRegionInfo(self, addr):
return ""
def qPathComplete(self):
return ""
def vFile(self, packet):
return ""
def vRun(self, packet):
return ""
def qLaunchGDBServer(self, host):
raise self.UnexpectedPacketException()
def qLaunchSuccess(self):
return ""
def QEnvironment(self, packet):
return "OK"
def QEnvironmentHexEncoded(self, packet):
return "OK"
def qRegisterInfo(self, num):
return ""
def k(self):
return ["W01", self.RESPONSE_DISCONNECT]
"""
Raised when we receive a packet for which there is no default action.
Override the responder class to implement behavior suitable for the test at
hand.
"""
class UnexpectedPacketException(Exception):
pass
class ServerChannel:
"""
A wrapper class for TCP or pty-based server.
"""
def get_connect_address(self):
"""Get address for the client to connect to."""
def get_connect_url(self):
"""Get URL suitable for process connect command."""
def close_server(self):
"""Close all resources used by the server."""
def accept(self):
"""Accept a single client connection to the server."""
def close_connection(self):
"""Close all resources used by the accepted connection."""
def recv(self):
"""Receive a data packet from the connected client."""
def sendall(self, data):
"""Send the data to the connected client."""
class ServerSocket(ServerChannel):
def __init__(self, family, type, proto, addr):
self._server_socket = socket.socket(family, type, proto)
self._connection = None
self._server_socket.bind(addr)
self._server_socket.listen(1)
def close_server(self):
self._server_socket.close()
def accept(self):
assert self._connection is None
# accept() is stubborn and won't fail even when the socket is
# shutdown, so we'll use a timeout
self._server_socket.settimeout(30.0)
client, client_addr = self._server_socket.accept()
# The connected client inherits its timeout from self._socket,
# but we'll use a blocking socket for the client
client.settimeout(None)
self._connection = client
def close_connection(self):
assert self._connection is not None
self._connection.close()
self._connection = None
def recv(self):
assert self._connection is not None
return self._connection.recv(4096)
def sendall(self, data):
assert self._connection is not None
return self._connection.sendall(data)
class TCPServerSocket(ServerSocket):
def __init__(self):
family, type, proto, _, addr = socket.getaddrinfo(
"localhost", 0, proto=socket.IPPROTO_TCP
)[0]
super().__init__(family, type, proto, addr)
def get_connect_address(self):
return "[{}]:{}".format(*self._server_socket.getsockname())
def get_connect_url(self):
return "connect://" + self.get_connect_address()
class UnixServerSocket(ServerSocket):
def __init__(self, addr):
super().__init__(socket.AF_UNIX, socket.SOCK_STREAM, 0, addr)
def get_connect_address(self):
return self._server_socket.getsockname()
def get_connect_url(self):
return "unix-connect://" + self.get_connect_address()
class PtyServerSocket(ServerChannel):
def __init__(self):
import pty
import tty
primary, secondary = pty.openpty()
tty.setraw(primary)
self._primary = io.FileIO(primary, "r+b")
self._secondary = io.FileIO(secondary, "r+b")
def get_connect_address(self):
libc = ctypes.CDLL(None)
libc.ptsname.argtypes = (ctypes.c_int,)
libc.ptsname.restype = ctypes.c_char_p
return libc.ptsname(self._primary.fileno()).decode()
def get_connect_url(self):
return "serial://" + self.get_connect_address()
def close_server(self):
self._secondary.close()
self._primary.close()
def recv(self):
try:
return self._primary.read(4096)
except OSError as e:
# closing the pty results in EIO on Linux, convert it to EOF
if e.errno == errno.EIO:
return b""
raise
def sendall(self, data):
return self._primary.write(data)
class MockGDBServer:
"""
A simple TCP-based GDB server that can test client behavior by receiving
commands and issuing custom-tailored responses.
Responses are generated via the .responder property, which should be an
instance of a class based on MockGDBServerResponder.
"""
responder = None
_socket = None
_thread = None
_receivedData = None
_receivedDataOffset = None
_shouldSendAck = True
def __init__(self, socket):
self._socket = socket
self.responder = MockGDBServerResponder()
def start(self):
# Start a thread that waits for a client connection.
self._thread = threading.Thread(target=self.run)
self._thread.start()
def stop(self):
self._thread.join()
self._thread = None
def get_connect_address(self):
return self._socket.get_connect_address()
def get_connect_url(self):
return self._socket.get_connect_url()
def run(self):
# For testing purposes, we only need to worry about one client
# connecting just one time.
try:
self._socket.accept()
except:
traceback.print_exc()
return
self._shouldSendAck = True
self._receivedData = ""
self._receivedDataOffset = 0
data = None
try:
while True:
data = seven.bitcast_to_string(self._socket.recv())
if data is None or len(data) == 0:
break
self._receive(data)
except self.TerminateConnectionException:
pass
except Exception as e:
print(
"An exception happened when receiving the response from the gdb server. Closing the client..."
)
traceback.print_exc()
finally:
self._socket.close_connection()
self._socket.close_server()
def _receive(self, data):
"""
Collects data, parses and responds to as many packets as exist.
Any leftover data is kept for parsing the next time around.
"""
self._receivedData += data
packet = self._parsePacket()
while packet is not None:
self._handlePacket(packet)
packet = self._parsePacket()
def _parsePacket(self):
"""
Reads bytes from self._receivedData, returning:
- a packet's contents if a valid packet is found
- the PACKET_ACK unique object if we got an ack
- None if we only have a partial packet
Raises an InvalidPacketException if unexpected data is received
or if checksums fail.
Once a complete packet is found at the front of self._receivedData,
its data is removed form self._receivedData.
"""
data = self._receivedData
i = self._receivedDataOffset
data_len = len(data)
if data_len == 0:
return None
if i == 0:
# If we're looking at the start of the received data, that means
# we're looking for the start of a new packet, denoted by a $.
# It's also possible we'll see an ACK here, denoted by a +
if data[0] == "+":
self._receivedData = data[1:]
return self.PACKET_ACK
if ord(data[0]) == 3:
self._receivedData = data[1:]
return self.PACKET_INTERRUPT
if data[0] == "$":
i += 1
else:
raise self.InvalidPacketException(
"Unexpected leading byte: %s" % data[0]
)
# If we're looking beyond the start of the received data, then we're
# looking for the end of the packet content, denoted by a #.
# Note that we pick up searching from where we left off last time
while i < data_len and data[i] != "#":
i += 1
# If there isn't enough data left for a checksum, just remember where
# we left off so we can pick up there the next time around
if i > data_len - 3:
self._receivedDataOffset = i
return None
# If we have enough data remaining for the checksum, extract it and
# compare to the packet contents
packet = data[1:i]
i += 1
try:
check = int(data[i : i + 2], 16)
except ValueError:
raise self.InvalidPacketException("Checksum is not valid hex")
i += 2
if check != checksum(packet):
raise self.InvalidPacketException(
"Checksum %02x does not match content %02x" % (check, checksum(packet))
)
# remove parsed bytes from _receivedData and reset offset so parsing
# can start on the next packet the next time around
self._receivedData = data[i:]
self._receivedDataOffset = 0
return packet
def _sendPacket(self, packet):
self._socket.sendall(seven.bitcast_to_bytes(frame_packet(packet)))
def _handlePacket(self, packet):
if packet is self.PACKET_ACK:
# Ignore ACKs from the client. For the future, we can consider
# adding validation code to make sure the client only sends ACKs
# when it's supposed to.
return
response = ""
# We'll handle the ack stuff here since it's not something any of the
# tests will be concerned about, and it'll get turned off quickly anyway.
if self._shouldSendAck:
self._socket.sendall(seven.bitcast_to_bytes("+"))
if packet == "QStartNoAckMode":
self._shouldSendAck = False
response = "OK"
elif self.responder is not None:
# Delegate everything else to our responder
response = self.responder.respond(packet)
if not isinstance(response, list):
response = [response]
for part in response:
if part is MockGDBServerResponder.RESPONSE_DISCONNECT:
raise self.TerminateConnectionException()
self._sendPacket(part)
PACKET_ACK = object()
PACKET_INTERRUPT = object()
class TerminateConnectionException(Exception):
pass
class InvalidPacketException(Exception):
pass
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