Pass NOTIFY_SOCKET and LISTEN_FDS env to OCI RUntime if set

In order to have sd_notify from systemd to work in containers
we need to pass down the NOTIFY_SOCKET environment variable to
the container.

LISTEN_FDS, tells the application inside of the container to use
socket activation and grab the FDS that are leaked into the container.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

Closes: #271
Approved by: umohnani8

libpod/oci.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/containerd/cgroups"
+	"github.com/coreos/go-systemd/activation"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -210,6 +211,14 @@ func (r *OCIRuntime) createContainer(ctr *Container, cgroupParent string) (err e
 	// 0, 1 and 2 are stdin, stdout and stderr
 	cmd.Env = append(r.conmonEnv, fmt.Sprintf("_OCI_SYNCPIPE=%d", 3))
 	cmd.Env = append(cmd.Env, fmt.Sprintf("_OCI_STARTPIPE=%d", 4))
+	if notify, ok := os.LookupEnv("NOTIFY_SOCKET"); ok {
+		cmd.Env = append(cmd.Env, fmt.Sprintf("NOTIFY_SOCKET=%s", notify))
+	}
+	if listenfds, ok := os.LookupEnv("LISTEN_FDS"); ok {
+		cmd.Env = append(cmd.Env, fmt.Sprintf("LISTEN_FDS=%s", listenfds))
+		fds := activation.Files(false)
+		cmd.ExtraFiles = append(cmd.ExtraFiles, fds...)
+	}
 
 	err = cmd.Start()
 	if err != nil {

test/e2e/run_test.go

@@ -185,6 +185,17 @@ var _ = Describe("Podman run", func() {
 		Expect(session.OutputToString()).To(ContainSubstring("15"))
 	})
 
+	It("podman run notify_socket", func() {
+		sock := "/run/sock"
+		os.Setenv("NOTIFY_SOCKET", sock)
+		session := podmanTest.Podman([]string{"run", "--rm", ALPINE, "printenv", "NOTIFY_SOCKET"})
+		session.Wait(10)
+		Expect(session.ExitCode()).To(Equal(0))
+		match, _ := session.GrepString(sock)
+		Expect(match).Should(BeTrue())
+		os.Unsetenv("NOTIFY_SOCKET")
+	})
+
 	It("podman run log-opt", func() {
 		log := filepath.Join(podmanTest.TempDir, "/container.log")
 		session := podmanTest.Podman([]string{"run", "--rm", "--log-opt", fmt.Sprintf("path=%s", log), ALPINE, "ls"})

vendor/github.com/coreos/go-systemd/activation/files.go

@@ -0,0 +1,52 @@
+// Copyright 2015 CoreOS, 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.
+
+// Package activation implements primitives for systemd socket activation.
+package activation
+
+import (
+	"os"
+	"strconv"
+	"syscall"
+)
+
+// based on: https://gist.github.com/alberts/4640792
+const (
+	listenFdsStart = 3
+)
+
+func Files(unsetEnv bool) []*os.File {
+	if unsetEnv {
+		defer os.Unsetenv("LISTEN_PID")
+		defer os.Unsetenv("LISTEN_FDS")
+	}
+
+	pid, err := strconv.Atoi(os.Getenv("LISTEN_PID"))
+	if err != nil || pid != os.Getpid() {
+		return nil
+	}
+
+	nfds, err := strconv.Atoi(os.Getenv("LISTEN_FDS"))
+	if err != nil || nfds == 0 {
+		return nil
+	}
+
+	files := make([]*os.File, 0, nfds)
+	for fd := listenFdsStart; fd < listenFdsStart+nfds; fd++ {
+		syscall.CloseOnExec(fd)
+		files = append(files, os.NewFile(uintptr(fd), "LISTEN_FD_"+strconv.Itoa(fd)))
+	}
+
+	return files
+}

vendor/github.com/coreos/go-systemd/activation/listeners.go

@@ -0,0 +1,60 @@
+// Copyright 2015 CoreOS, 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.
+
+package activation
+
+import (
+	"crypto/tls"
+	"net"
+)
+
+// Listeners returns a slice containing a net.Listener for each matching socket type
+// passed to this process.
+//
+// The order of the file descriptors is preserved in the returned slice.
+// Nil values are used to fill any gaps. For example if systemd were to return file descriptors
+// corresponding with "udp, tcp, tcp", then the slice would contain {nil, net.Listener, net.Listener}
+func Listeners(unsetEnv bool) ([]net.Listener, error) {
+	files := Files(unsetEnv)
+	listeners := make([]net.Listener, len(files))
+
+	for i, f := range files {
+		if pc, err := net.FileListener(f); err == nil {
+			listeners[i] = pc
+		}
+	}
+	return listeners, nil
+}
+
+// TLSListeners returns a slice containing a net.listener for each matching TCP socket type
+// passed to this process.
+// It uses default Listeners func and forces TCP sockets handlers to use TLS based on tlsConfig.
+func TLSListeners(unsetEnv bool, tlsConfig *tls.Config) ([]net.Listener, error) {
+	listeners, err := Listeners(unsetEnv)
+
+	if listeners == nil || err != nil {
+		return nil, err
+	}
+
+	if tlsConfig != nil && err == nil {
+		for i, l := range listeners {
+			// Activate TLS only for TCP sockets
+			if l.Addr().Network() == "tcp" {
+				listeners[i] = tls.NewListener(l, tlsConfig)
+			}
+		}
+	}
+
+	return listeners, err
+}

vendor/github.com/coreos/go-systemd/activation/packetconns.go

@@ -0,0 +1,37 @@
+// Copyright 2015 CoreOS, 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.
+
+package activation
+
+import (
+	"net"
+)
+
+// PacketConns returns a slice containing a net.PacketConn for each matching socket type
+// passed to this process.
+//
+// The order of the file descriptors is preserved in the returned slice.
+// Nil values are used to fill any gaps. For example if systemd were to return file descriptors
+// corresponding with "udp, tcp, udp", then the slice would contain {net.PacketConn, nil, net.PacketConn}
+func PacketConns(unsetEnv bool) ([]net.PacketConn, error) {
+	files := Files(unsetEnv)
+	conns := make([]net.PacketConn, len(files))
+
+	for i, f := range files {
+		if pc, err := net.FilePacketConn(f); err == nil {
+			conns[i] = pc
+		}
+	}
+	return conns, nil
+}