[CRIU] [PATCH] Query Dirty Tracking support via RPC

[Adrian Reber]

From: Adrian Reber <areber at redhat.com>

There are still systems which do not support dirty memory tracking.
This offers an interface to query the dirty memory tracking
availability via RPC. This is in preparation of a p.haul change
which will use this RPC interface to automatically detect if
pre-dumps should be executed or not.

Signed-off-by: Adrian Reber <areber at redhat.com>
---
 cr-service.c       | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 protobuf/rpc.proto |  2 ++
 2 files changed, 49 insertions(+)

diff --git a/cr-service.c b/cr-service.c
index 938ea9e..53ea6e2 100644
--- a/cr-service.c
+++ b/cr-service.c
@@ -32,6 +32,7 @@
 #include "security.h"
 #include "sockets.h"
 #include "irmap.h"
+#include "kerndat.h"
 
 #include "setproctitle.h"
 
@@ -723,10 +724,53 @@ static int chk_keepopen_req(CriuReq *msg)
 	else if (msg->type == CRIU_REQ_TYPE__CPUINFO_DUMP ||
 		 msg->type == CRIU_REQ_TYPE__CPUINFO_CHECK)
 		return 0;
+	else if (msg->type == CRIU_REQ_TYPE__DIRTY_TRACKING)
+		return 0;
 
 	return -1;
 }
 
+static int handle_dirty_tracking(int sk, CriuReq *msg)
+{
+	CriuResp resp = CRIU_RESP__INIT;
+	bool success = false;
+	int pid, status;
+
+	pid = fork();
+	if (pid < 0) {
+		pr_perror("Can't fork");
+		goto out;
+	}
+
+	if (pid == 0) {
+		int ret = 1;
+
+		if (setup_opts_from_req(sk, msg->opts))
+			goto cout;
+
+		setproctitle("dirty-tracking --rpc -D %s",
+			     images_dir);
+
+		kerndat_get_dirty_track();
+
+		if (kdat.has_dirty_track)
+			ret = 0;
+cout:
+		exit(ret);
+	}
+
+	wait(&status);
+	if (!WIFEXITED(status) || WEXITSTATUS(status))
+		goto out;
+
+	success = true;
+out:
+	resp.type = msg->type;
+	resp.success = success;
+
+	return send_criu_msg(sk, &resp);
+}
+
 static int handle_cpuinfo(int sk, CriuReq *msg)
 {
 	CriuResp resp = CRIU_RESP__INIT;
@@ -804,6 +848,9 @@ more:
 	case CRIU_REQ_TYPE__CPUINFO_CHECK:
 		ret = handle_cpuinfo(sk, msg);
 		break;
+	case CRIU_REQ_TYPE__DIRTY_TRACKING:
+		ret = handle_dirty_tracking(sk, msg);
+		break;
 
 	default:
 		send_criu_err(sk, "Invalid req");
diff --git a/protobuf/rpc.proto b/protobuf/rpc.proto
index 466780e..1f0e66e 100644
--- a/protobuf/rpc.proto
+++ b/protobuf/rpc.proto
@@ -115,6 +115,8 @@ enum criu_req_type {
 
 	CPUINFO_DUMP	= 7;
 	CPUINFO_CHECK	= 8;
+
+	DIRTY_TRACKING	= 9;
 }
 
 /*
-- 
2.4.3