Runsc checkpoint works.

This is the first iteration of checkpoint that actually saves to a file.
Tests for checkpoint are included.

Ran into an issue when private unix sockets are enabled. An error message
was added for this case and the mutex state was set.

PiperOrigin-RevId: 200269470
Change-Id: I28d29a9f92c44bf73dc4a4b12ae0509ee4070e93

2 files changed, 12 insertions, 2 deletions

diff --git a/pkg/sentry/fs/gofer/session.go b/pkg/sentry/fs/gofer/session.go
index 1076e3e55..baf00d8e7 100644
--- a/pkg/sentry/fs/gofer/session.go
+++ b/pkg/sentry/fs/gofer/session.go
@@ -28,8 +28,9 @@ import (
 )
 
 type endpointMap struct {
-	mu sync.RWMutex
-	m  map[device.MultiDeviceKey]unix.BoundEndpoint
+	mu sync.RWMutex `state:"nosave"`
+	// TODO: Make map with private unix sockets savable.
+	m map[device.MultiDeviceKey]unix.BoundEndpoint
 }
 
 // add adds the endpoint to the map.
diff --git a/pkg/sentry/fs/gofer/session_state.go b/pkg/sentry/fs/gofer/session_state.go
index 4d993a219..0154810c8 100644
--- a/pkg/sentry/fs/gofer/session_state.go
+++ b/pkg/sentry/fs/gofer/session_state.go
@@ -22,6 +22,15 @@ import (
 	"gvisor.googlesource.com/gvisor/pkg/unet"
 )
 
+// beforeSave is invoked by stateify.
+//
+// TODO: Make map with private unix sockets savable.
+func (e *endpointMap) beforeSave() {
+	if len(e.m) != 0 {
+		panic("EndpointMap with existing private unix sockets cannot be saved")
+	}
+}
+
 // afterLoad is invoked by stateify.
 func (s *session) afterLoad() {
 	// The restore environment contains the 9p connection of this mount.