pycriu: Fix self-dump failure with explicit PID

When `opts.pid` is explicitly set to `os.getpid()`, `pycriu` fails to
daemonize the `criu` process. This causes `criu` to run as a child of
the dumped process, leading to the error "The criu itself is within
dumped tree".

This can be fixed by modifying `_send_req_and_recv_resp` to check if the
target PID matches the current process PID. If so, it enables daemon
mode, ensuring `criu` is detached and the dump succeeds.

Signed-off-by: unichronic <ishuvam.pal@gmail.com>

Author: unichronic

lib/pycriu/criu.py

@@ -242,7 +242,7 @@ def _send_req_and_recv_resp(self, req):
         # 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'):
+        if req.type == rpc.DUMP and (not req.opts.HasField('pid') or req.opts.pid == os.getpid()):
             daemon = True
 
         try: