# Same as libcriu for C.
import socket
import errno
import fcntl
import os
import struct
import pycriu.rpc_pb2 as rpc
class _criu_comm:
"""
Base class for communication classes.
"""
COMM_SK = 0
COMM_FD = 1
COMM_BIN = 2
comm_type = None
comm = None
sk = None
def connect(self, daemon):
"""
Connect to criu and return socket object.
daemon -- is for whether or not criu should daemonize if executing criu from binary(comm_bin).
"""
pass
def disconnect(self):
"""
Disconnect from criu.
"""
pass
class _criu_comm_sk(_criu_comm):
"""
Communication class for unix socket.
"""
def __init__(self, sk_path):
self.comm_type = self.COMM_SK
self.comm = sk_path
def connect(self, daemon):
self.sk = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
self.sk.connect(self.comm)
return self.sk
def disconnect(self):
self.sk.close()
class _criu_comm_fd(_criu_comm):
"""
Communication class for file descriptor.
"""
def __init__(self, fd):
self.comm_type = self.COMM_FD
self.comm = fd
def connect(self, daemon):
self.sk = socket.fromfd(self.comm, socket.AF_UNIX,
socket.SOCK_SEQPACKET)
return self.sk
def disconnect(self):
self.sk.close()
class _criu_comm_bin(_criu_comm):
"""
Communication class for binary.
"""
def __init__(self, bin_path):
self.comm_type = self.COMM_BIN
self.comm = bin_path
self.swrk = None
self.daemon = None
def connect(self, daemon):
# Kind of the same thing we do in libcriu
css = socket.socketpair(socket.AF_UNIX, socket.SOCK_SEQPACKET)
flags = fcntl.fcntl(css[1], fcntl.F_GETFD)
fcntl.fcntl(css[1], fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC)
flags = fcntl.fcntl(css[0], fcntl.F_GETFD)
fcntl.fcntl(css[0], fcntl.F_SETFD, flags & ~fcntl.FD_CLOEXEC)
self.daemon = daemon
p = os.fork()
if p == 0:
def exec_criu():
os.close(0)
os.close(1)
os.close(2)
css[0].send(struct.pack('i', os.getpid()))
os.execv(self.comm,
[self.comm, 'swrk',
"%d" % css[0].fileno()])
os._exit(1)
if daemon:
# Python has no daemon(3) alternative,
# so we need to mimic it ourself.
p = os.fork()
if p == 0:
os.setsid()
exec_criu()
else:
os._exit(0)
else:
exec_criu()
else:
if daemon:
os.waitpid(p, 0)
css[0].close()
self.swrk = struct.unpack('i', css[1].recv(4))[0]
self.sk = css[1]
return self.sk
def disconnect(self):
self.sk.close()
if not self.daemon:
os.waitpid(self.swrk, 0)
class CRIUException(Exception):
"""
Exception class for handling and storing criu errors.
"""
typ = None
_str = None
def __str__(self):
return self._str
class CRIUExceptionInternal(CRIUException):
"""
Exception class for handling and storing internal errors.
"""
def __init__(self, typ, s):
self.typ = typ
self._str = "%s failed with internal error: %s" % (
rpc.criu_req_type.Name(self.typ), s)
class CRIUExceptionExternal(CRIUException):
"""
Exception class for handling and storing criu RPC errors.
"""
def __init__(self, req_typ, resp_typ, errno):
self.typ = req_typ
self.resp_typ = resp_typ
self.errno = errno
self._str = self._gen_error_str()
def _gen_error_str(self):
s = "%s failed: " % (rpc.criu_req_type.Name(self.typ), )
if self.typ != self.resp_typ:
s += "Unexpected response type %d: " % (self.resp_typ, )
s += "Error(%d): " % (self.errno, )
if self.errno == errno.EBADRQC:
s += "Bad options"
if self.typ == rpc.DUMP:
if self.errno == errno.ESRCH:
s += "No process with such pid"
if self.typ == rpc.RESTORE:
if self.errno == errno.EEXIST:
s += "Process with requested pid already exists"
s += "Unknown"
return s
class criu:
"""
Call criu through RPC.
"""
opts = None #CRIU options in pb format
_comm = None #Communication method
def __init__(self):
self.use_binary('criu')
self.opts = rpc.criu_opts()
self.sk = None
def use_sk(self, sk_name):
"""
Access criu using unix socket which that belongs to criu service daemon.
"""
self._comm = _criu_comm_sk(sk_name)
def use_fd(self, fd):
"""
Access criu using provided fd.
"""
self._comm = _criu_comm_fd(fd)
def use_binary(self, bin_name):
"""
Access criu by execing it using provided path to criu binary.
"""
self._comm = _criu_comm_bin(bin_name)
def _send_req_and_recv_resp(self, req):
"""
As simple as send request and receive response.
"""
# In case of self-dump we need to spawn criu swrk detached
# from our current process, as criu has a hard time separating
# process resources from its own if criu is located in a same
# process tree it is trying to dump.
daemon = False
if req.type == rpc.DUMP and not req.opts.HasField('pid'):
daemon = True
try:
if not self.sk:
s = self._comm.connect(daemon)
else:
s = self.sk
if req.keep_open:
self.sk = s
s.send(req.SerializeToString())
buf = s.recv(len(s.recv(1, socket.MSG_TRUNC | socket.MSG_PEEK)))
if not req.keep_open:
self._comm.disconnect()
resp = rpc.criu_resp()
resp.ParseFromString(buf)
except Exception as e:
raise CRIUExceptionInternal(req.type, str(e))
return resp
def check(self):
"""
Checks whether the kernel support is up-to-date.
"""
req = rpc.criu_req()
req.type = rpc.CHECK
resp = self._send_req_and_recv_resp(req)
if not resp.success:
raise CRIUExceptionExternal(req.type, resp.type, resp.cr_errno)
def dump(self):
"""
Checkpoint a process/tree identified by opts.pid.
"""
req = rpc.criu_req()
req.type = rpc.DUMP
req.opts.MergeFrom(self.opts)
resp = self._send_req_and_recv_resp(req)
if not resp.success:
raise CRIUExceptionExternal(req.type, resp.type, resp.cr_errno)
return resp.dump
def pre_dump(self):
"""
Checkpoint a process/tree identified by opts.pid.
"""
req = rpc.criu_req()
req.type = rpc.PRE_DUMP
req.opts.MergeFrom(self.opts)
resp = self._send_req_and_recv_resp(req)
if not resp.success:
raise CRIUExceptionExternal(req.type, resp.type, resp.cr_errno)
return resp.dump
def restore(self):
"""
Restore a process/tree.
"""
req = rpc.criu_req()
req.type = rpc.RESTORE
req.opts.MergeFrom(self.opts)
resp = self._send_req_and_recv_resp(req)
if not resp.success:
raise CRIUExceptionExternal(req.type, resp.type, resp.cr_errno)
return resp.restore
def page_server_chld(self):
req = rpc.criu_req()
req.type = rpc.PAGE_SERVER_CHLD
req.opts.MergeFrom(self.opts)
req.keep_open = True
resp = self._send_req_and_recv_resp(req)
if not resp.success:
raise CRIUExceptionExternal(req.type, resp.type, resp.cr_errno)
return resp.ps
def wait_pid(self, pid):
req = rpc.criu_req()
req.type = rpc.WAIT_PID
req.pid = pid
resp = self._send_req_and_recv_resp(req)
if not resp.success:
raise CRIUExceptionExternal(req.type, resp.type, resp.cr_errno)
return resp.status