Add API for communicating with Docker volume plugins

Docker provides extensibility through a plugin system, of which
several types are available. This provides an initial library API
for communicating with one type of plugins, volume plugins.
Volume plugins allow for an external service to create and manage
a volume on Podman's behalf.

This does not integrate the plugin system into Libpod or Podman
yet; that will come in subsequent pull requests.

Signed-off-by: Matthew Heon <mheon@redhat.com>

3 files changed, 208 insertions, 0 deletions

diff --git a/vendor/github.com/coreos/go-systemd/activation/files.go b/vendor/github.com/coreos/go-systemd/activation/files.go
new file mode 100644
index 000000000..29dd18def
--- /dev/null
+++ b/vendor/github.com/coreos/go-systemd/activation/files.go
@@ -0,0 +1,67 @@
+// 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"
+	"strings"
+	"syscall"
+)
+
+const (
+	// listenFdsStart corresponds to `SD_LISTEN_FDS_START`.
+	listenFdsStart = 3
+)
+
+// Files returns a slice containing a `os.File` object for each
+// file descriptor passed to this process via systemd fd-passing protocol.
+//
+// The order of the file descriptors is preserved in the returned slice.
+// `unsetEnv` is typically set to `true` in order to avoid clashes in
+// fd usage and to avoid leaking environment flags to child processes.
+func Files(unsetEnv bool) []*os.File {
+	if unsetEnv {
+		defer os.Unsetenv("LISTEN_PID")
+		defer os.Unsetenv("LISTEN_FDS")
+		defer os.Unsetenv("LISTEN_FDNAMES")
+	}
+
+	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
+	}
+
+	names := strings.Split(os.Getenv("LISTEN_FDNAMES"), ":")
+
+	files := make([]*os.File, 0, nfds)
+	for fd := listenFdsStart; fd < listenFdsStart+nfds; fd++ {
+		syscall.CloseOnExec(fd)
+		name := "LISTEN_FD_" + strconv.Itoa(fd)
+		offset := fd - listenFdsStart
+		if offset < len(names) && len(names[offset]) > 0 {
+			name = names[offset]
+		}
+		files = append(files, os.NewFile(uintptr(fd), name))
+	}
+
+	return files
+}
diff --git a/vendor/github.com/coreos/go-systemd/activation/listeners.go b/vendor/github.com/coreos/go-systemd/activation/listeners.go
new file mode 100644
index 000000000..bb5cc2311
--- /dev/null
+++ b/vendor/github.com/coreos/go-systemd/activation/listeners.go
@@ -0,0 +1,103 @@
+// 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() ([]net.Listener, error) {
+	files := Files(true)
+	listeners := make([]net.Listener, len(files))
+
+	for i, f := range files {
+		if pc, err := net.FileListener(f); err == nil {
+			listeners[i] = pc
+			f.Close()
+		}
+	}
+	return listeners, nil
+}
+
+// ListenersWithNames maps a listener name to a set of net.Listener instances.
+func ListenersWithNames() (map[string][]net.Listener, error) {
+	files := Files(true)
+	listeners := map[string][]net.Listener{}
+
+	for _, f := range files {
+		if pc, err := net.FileListener(f); err == nil {
+			current, ok := listeners[f.Name()]
+			if !ok {
+				listeners[f.Name()] = []net.Listener{pc}
+			} else {
+				listeners[f.Name()] = append(current, pc)
+			}
+			f.Close()
+		}
+	}
+	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(tlsConfig *tls.Config) ([]net.Listener, error) {
+	listeners, err := Listeners()
+
+	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
+}
+
+// TLSListenersWithNames maps a listener name to a net.Listener with
+// the associated TLS configuration.
+func TLSListenersWithNames(tlsConfig *tls.Config) (map[string][]net.Listener, error) {
+	listeners, err := ListenersWithNames()
+
+	if listeners == nil || err != nil {
+		return nil, err
+	}
+
+	if tlsConfig != nil && err == nil {
+		for _, ll := range listeners {
+			// Activate TLS only for TCP sockets
+			for i, l := range ll {
+				if l.Addr().Network() == "tcp" {
+					ll[i] = tls.NewListener(l, tlsConfig)
+				}
+			}
+		}
+	}
+
+	return listeners, err
+}
diff --git a/vendor/github.com/coreos/go-systemd/activation/packetconns.go b/vendor/github.com/coreos/go-systemd/activation/packetconns.go
new file mode 100644
index 000000000..a97206785
--- /dev/null
+++ b/vendor/github.com/coreos/go-systemd/activation/packetconns.go
@@ -0,0 +1,38 @@
+// 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() ([]net.PacketConn, error) {
+	files := Files(true)
+	conns := make([]net.PacketConn, len(files))
+
+	for i, f := range files {
+		if pc, err := net.FilePacketConn(f); err == nil {
+			conns[i] = pc
+			f.Close()
+		}
+	}
+	return conns, nil
+}