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Well described here: [[Self_dump]].
Well described here: [[Self_dump]].
== Protocol Buffers ==
== CRIU request ==
criu_req is used to wrap requests to provide compatibility with an older versions of rpc.
There are three types of structures for now:
Any request must be wrapped into criu_req to send to criu.
=== Dump request ===
criu_dump_req is used to store dump options from client.
<pre>
message criu_req {
required criu_req_type type = 1;
optional criu_dump_req dump = 2;
}
</pre>
There is only 1 request/response type for now.
<pre>enum criu_req_type {
EMPTY = 0;
DUMP = 1;
}
</pre>
=== CRIU dump request ===
criu_dump_req is used to store dump options.
<pre>message criu_dump_req {
<pre>message criu_dump_req {
optional int32 pid = 1;
required int32 images_dir_fd = 1;
optional bool leave_running = 2;
optional int32 pid = 2;
optional bool ext_unix_sk = 3;
optional bool tcp_established = 4;
optional bool leave_running = 3;
optional bool evasive_devices = 5;
optional bool ext_unix_sk = 4;
optional bool shell_job = 6;
optional bool tcp_established = 5;
optional bool file_locks = 7;
optional bool evasive_devices = 6;
optional bool shell_job = 7;
optional bool file_locks = 8;
optional int32 log_level = 9 [default = 2];
optional int32 log_level = 9 [default = 2];
}</pre>
}</pre>
For other options description, please run "criu -h".
For other options description, please run "criu -h".
=== Dump response ===
== CRIU response ==
criu_resp is a wrapper for responses. It consists of success bool field, response type field and response, that depends on sent request type.
<pre>message criu_resp {
required criu_req_type type = 1;
required bool success = 2;
optional criu_dump_resp dump = 3;
}
</pre>
=== CRIU dump response ===
criu_dump_resp is used to store response from CRIU.
criu_dump_resp is used to store response from CRIU.
<pre>
<pre>
message criu_dump_resp {
message criu_dump_resp {
optional bool restored = 1;
optional bool restored = 2;
}
}
</pre>
</pre>
Field "restored" is set to "true" if process was restored.
Field "restored" is set to "true" if process was restored.
== Server ==
== Server ==
On a server side, CRIU creates SOCK_SEQPACKET Unix socket and listens for connections on it. After receiving criu_msg, CRIU processes it and do what is requested and sends response back.
On a server side, CRIU creates SOCK_SEQPACKET Unix socket and listens for connections on it. After receiving criu_req, CRIU processes it, do what is requested and sends response back.
To launch service server run:
To launch service server run:
== Client ==
== Client ==
Client, in its turn, must connect to service socket, send criu_msg with request in it, and wait for a criu_msg with response.
Client, in its turn, must connect to service socket, send criu_msg with request in it, and wait for a criu_resp with response.
You can find examples of client programs in C and Python in test/rpc/.
You can find examples of client programs in C and Python in test/rpc/.