Enable checkpoint/restore in cases of UDS use.

Previously, processes which used file-system Unix Domain Sockets could not be
checkpoint-ed in runsc because the sockets were saved with their inode
numbers which do not necessarily remain the same upon restore. Now,
the sockets are also saved with their paths so that the new inodes
can be determined for the sockets based on these paths after restoring.
Tests for cases with UDS use are included. Test cleanup to come.

PiperOrigin-RevId: 208268781
Change-Id: Ieaa5d5d9a64914ca105cae199fd8492710b1d7ec

1 files changed, 83 insertions, 0 deletions

diff --git a/runsc/container/uds_test_app.go b/runsc/container/uds_test_app.go
new file mode 100644
index 000000000..bef98ac66
--- /dev/null
+++ b/runsc/container/uds_test_app.go
@@ -0,0 +1,83 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Binary uds-test-app opens a socket and reads a series of numbers
+// which are then written to an output file.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"strconv"
+	"time"
+)
+
+var (
+	fileName   = flag.String("file", "", "name of output file")
+	socketPath = flag.String("socket", "", "path to socket")
+)
+
+func server(listener net.Listener, f *os.File) {
+	buf := make([]byte, 16)
+
+	for {
+		c, err := listener.Accept()
+		if err != nil {
+			log.Fatal("error accepting connection:", err)
+		}
+		nr, err := c.Read(buf)
+		if err != nil {
+			log.Fatal("error reading from buf:", err)
+		}
+		data := buf[0:nr]
+		fmt.Fprintf(f, string(data)+"\n")
+	}
+}
+
+func main() {
+	flag.Parse()
+	if *fileName == "" || *socketPath == "" {
+		log.Fatalf("Flags cannot be empty, given: fileName=%s, socketPath=%s", *fileName, *socketPath)
+	}
+	outputFile, err := os.OpenFile(*fileName, os.O_WRONLY|os.O_CREATE, 0666)
+	if err != nil {
+		log.Fatal("error opening output file:", err)
+	}
+
+	socket := *socketPath
+	defer os.Remove(socket)
+
+	listener, err := net.Listen("unix", socket)
+	if err != nil {
+		log.Fatal("error listening on socket:", err)
+	}
+
+	go server(listener, outputFile)
+	for i := 0; ; i++ {
+
+		conn, err := net.Dial("unix", socket)
+		if err != nil {
+			log.Fatal("error dialing:", err)
+		}
+		if _, err := conn.Write([]byte(strconv.Itoa(i))); err != nil {
+			log.Fatal("error writing:", err)
+		}
+		conn.Close()
+		time.Sleep(100 * time.Millisecond)
+	}
+
+}