Merge pull request #861 from justincormack/go-runc-port

Portability fixes for containerd shim

cmd/containerd-shim/main_unix.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"os/signal"
 	"strings"
 
 	"golang.org/x/sys/unix"
@@ -17,9 +16,7 @@ import (
 	shimapi "github.com/containerd/containerd/api/services/shim"
 	"github.com/containerd/containerd/linux/shim"
 	"github.com/containerd/containerd/reaper"
-	"github.com/containerd/containerd/sys"
 	"github.com/containerd/containerd/version"
-	runc "github.com/containerd/go-runc"
 	"github.com/urfave/cli"
 )
 
@@ -81,21 +78,6 @@ func main() {
 	}
 }
 
-// setupSignals creates a new signal handler for all signals and sets the shim as a
-// sub-reaper so that the container processes are reparented
-func setupSignals() (chan os.Signal, error) {
-	signals := make(chan os.Signal, 2048)
-	signal.Notify(signals)
-	// make sure runc is setup to use the monitor
-	// for waiting on processes
-	runc.Monitor = reaper.Default
-	// set the shim as the subreaper for all orphaned processes created by the container
-	if err := sys.SetSubreaper(1); err != nil {
-		return nil, err
-	}
-	return signals, nil
-}
-
 // serve serves the grpc API over a unix socket at the provided path
 // this function does not block
 func serve(server *grpc.Server, path string) error {
@@ -131,8 +113,3 @@ func handleSignals(signals chan os.Signal, server *grpc.Server) error {
 	}
 	return nil
 }
-
-// setupRoot sets up the root as the shim is started in its own mount namespace
-func setupRoot() error {
-	return unix.Mount("", "/", "", unix.MS_SLAVE|unix.MS_REC, "")
-}

cmd/containerd-shim/shim_linux.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"os"
+	"os/signal"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/containerd/containerd/reaper"
+	"github.com/containerd/containerd/sys"
+	runc "github.com/containerd/go-runc"
+)
+
+// setupSignals creates a new signal handler for all signals and sets the shim as a
+// sub-reaper so that the container processes are reparented
+func setupSignals() (chan os.Signal, error) {
+	signals := make(chan os.Signal, 2048)
+	signal.Notify(signals)
+	// make sure runc is setup to use the monitor
+	// for waiting on processes
+	runc.Monitor = reaper.Default
+	// set the shim as the subreaper for all orphaned processes created by the container
+	if err := sys.SetSubreaper(1); err != nil {
+		return nil, err
+	}
+	return signals, nil
+}
+
+// setupRoot sets up the root as the shim is started in its own mount namespace
+func setupRoot() error {
+	return unix.Mount("", "/", "", unix.MS_SLAVE|unix.MS_REC, "")
+}

cmd/containerd-shim/shim_unix.go

@@ -0,0 +1,27 @@
+// +build !linux
+
+package main
+
+import (
+	"os"
+	"os/signal"
+
+	"github.com/containerd/containerd/reaper"
+	runc "github.com/containerd/go-runc"
+)
+
+// setupSignals creates a new signal handler for all signals and sets the shim as a
+// sub-reaper so that the container processes are reparented
+func setupSignals() (chan os.Signal, error) {
+	signals := make(chan os.Signal, 2048)
+	signal.Notify(signals)
+	// make sure runc is setup to use the monitor
+	// for waiting on processes
+	runc.Monitor = reaper.Default
+	return signals, nil
+}
+
+// setupRoot is a no op except on Linux
+func setupRoot() error {
+	return nil
+}

linux/shim/exec.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build !windows
 
 package shim
 

linux/shim/init.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build !windows
 
 package shim
 

linux/shim/io.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build !windows
 
 package shim
 

linux/shim/process.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build !windows
 
 package shim
 

linux/shim/service.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build !windows
 
 package shim
 

vendor.conf

@@ -1,5 +1,5 @@
 github.com/coreos/go-systemd 48702e0da86bd25e76cfef347e2adeb434a0d0a6
-github.com/containerd/go-runc 5fe4d8cb7fdc0fae5f5a7f4f1d65a565032401b2
+github.com/containerd/go-runc 66d084de463f26efe84e6a5669e573fa6202e814
 github.com/containerd/console a3863895279f5104533fd999c1babf80faffd98c
 github.com/containerd/cgroups 7b2d1a0f50963678d5799e29d17a4d611f5a5dee
 github.com/docker/go-metrics 8fd5772bf1584597834c6f7961a530f06cbfbb87

vendor/github.com/containerd/go-runc/command_linux.go

@@ -0,0 +1,21 @@
+package runc
+
+import (
+	"context"
+	"os/exec"
+	"syscall"
+)
+
+func (r *Runc) command(context context.Context, args ...string) *exec.Cmd {
+	command := r.Command
+	if command == "" {
+		command = DefaultCommand
+	}
+	cmd := exec.CommandContext(context, command, append(r.args(), args...)...)
+	if r.PdeathSignal != 0 {
+		cmd.SysProcAttr = &syscall.SysProcAttr{
+			Pdeathsig: r.PdeathSignal,
+		}
+	}
+	return cmd
+}

vendor/github.com/containerd/go-runc/command_other.go

@@ -0,0 +1,16 @@
+// +build !linux
+
+package runc
+
+import (
+	"context"
+	"os/exec"
+)
+
+func (r *Runc) command(context context.Context, args ...string) *exec.Cmd {
+	command := r.Command
+	if command == "" {
+		command = DefaultCommand
+	}
+	return exec.CommandContext(context, command, append(r.args(), args...)...)
+}

vendor/github.com/containerd/go-runc/console.go

@@ -10,7 +10,7 @@ import (
 	"path/filepath"
 
 	"github.com/containerd/console"
-	"github.com/opencontainers/runc/libcontainer/utils"
+	"golang.org/x/sys/unix"
 )
 
 // NewConsoleSocket creates a new unix socket at the provided path to accept a
@@ -20,13 +20,16 @@ func NewConsoleSocket(path string) (*Socket, error) {
 	if err != nil {
 		return nil, err
 	}
-	l, err := net.Listen("unix", abs)
+	addr, err := net.ResolveUnixAddr("unix", abs)
+	if err != nil {
+		return nil, err
+	}
+	l, err := net.ListenUnix("unix", addr)
 	if err != nil {
 		return nil, err
 	}
 	return &Socket{
 		l:    l,
-		path: abs,
 	}, nil
 }
 
@@ -41,27 +44,73 @@ func NewTempConsoleSocket() (*Socket, error) {
 	if err != nil {
 		return nil, err
 	}
-	l, err := net.Listen("unix", abs)
+	addr, err := net.ResolveUnixAddr("unix", abs)
+	if err != nil {
+		return nil, err
+	}
+	l, err := net.ListenUnix("unix", addr)
 	if err != nil {
 		return nil, err
 	}
 	return &Socket{
 		l:     l,
 		rmdir: true,
-		path:  abs,
 	}, nil
 }
 
 // Socket is a unix socket that accepts the pty master created by runc
 type Socket struct {
-	path  string
 	rmdir bool
-	l     net.Listener
+	l     *net.UnixListener
 }
 
 // Path returns the path to the unix socket on disk
 func (c *Socket) Path() string {
-	return c.path
+	return c.l.Addr().String()
+}
+
+// recvFd waits for a file descriptor to be sent over the given AF_UNIX
+// socket. The file name of the remote file descriptor will be recreated
+// locally (it is sent as non-auxiliary data in the same payload).
+func recvFd(socket *net.UnixConn) (*os.File, error) {
+	const MaxNameLen = 4096
+	var oobSpace = unix.CmsgSpace(4)
+
+	name := make([]byte, MaxNameLen)
+	oob := make([]byte, oobSpace)
+
+	n, oobn, _, _, err := socket.ReadMsgUnix(name, oob)
+	if err != nil {
+		return nil, err
+	}
+
+	if n >= MaxNameLen || oobn != oobSpace {
+		return nil, fmt.Errorf("recvfd: incorrect number of bytes read (n=%d oobn=%d)", n, oobn)
+	}
+
+	// Truncate.
+	name = name[:n]
+	oob = oob[:oobn]
+
+	scms, err := unix.ParseSocketControlMessage(oob)
+	if err != nil {
+		return nil, err
+	}
+	if len(scms) != 1 {
+		return nil, fmt.Errorf("recvfd: number of SCMs is not 1: %d", len(scms))
+	}
+	scm := scms[0]
+
+	fds, err := unix.ParseUnixRights(&scm)
+	if err != nil {
+		return nil, err
+	}
+	if len(fds) != 1 {
+		return nil, fmt.Errorf("recvfd: number of fds is not 1: %d", len(fds))
+	}
+	fd := uintptr(fds[0])
+
+	return os.NewFile(fd, string(name)), nil
 }
 
 // ReceiveMaster blocks until the socket receives the pty master
@@ -71,15 +120,11 @@ func (c *Socket) ReceiveMaster() (console.Console, error) {
 		return nil, err
 	}
 	defer conn.Close()
-	unix, ok := conn.(*net.UnixConn)
+	uc, ok := conn.(*net.UnixConn)
 	if !ok {
 		return nil, fmt.Errorf("received connection which was not a unix socket")
 	}
-	sock, err := unix.File()
+	f, err := recvFd(uc)
-	if err != nil {
-		return nil, err
-	}
-	f, err := utils.RecvFd(sock)
 	if err != nil {
 		return nil, err
 	}
@@ -90,7 +135,7 @@ func (c *Socket) ReceiveMaster() (console.Console, error) {
 func (c *Socket) Close() error {
 	err := c.l.Close()
 	if c.rmdir {
-		if rerr := os.RemoveAll(filepath.Dir(c.path)); err == nil {
+		if rerr := os.RemoveAll(filepath.Dir(c.Path())); err == nil {
 			err = rerr
 		}
 	}

vendor/github.com/containerd/go-runc/runc.go

@@ -523,20 +523,6 @@ func (r *Runc) args() (out []string) {
 	return out
 }
 
-func (r *Runc) command(context context.Context, args ...string) *exec.Cmd {
-	command := r.Command
-	if command == "" {
-		command = DefaultCommand
-	}
-	cmd := exec.CommandContext(context, command, append(r.args(), args...)...)
-	if r.PdeathSignal != 0 {
-		cmd.SysProcAttr = &syscall.SysProcAttr{
-			Pdeathsig: r.PdeathSignal,
-		}
-	}
-	return cmd
-}
-
 // runOrError will run the provided command.  If an error is
 // encountered and neither Stdout or Stderr was set the error and the
 // stderr of the command will be returned in the format of <error>:

vendor/github.com/opencontainers/runc/libcontainer/utils/cmsg.go

@@ -1,95 +0,0 @@
-// +build linux
-
-package utils
-
-/*
- * Copyright 2016, 2017 SUSE LLC
- *
- * 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.
- */
-
-import (
-	"fmt"
-	"os"
-
-	"golang.org/x/sys/unix"
-)
-
-// MaxSendfdLen is the maximum length of the name of a file descriptor being
-// sent using SendFd. The name of the file handle returned by RecvFd will never
-// be larger than this value.
-const MaxNameLen = 4096
-
-// oobSpace is the size of the oob slice required to store a single FD. Note
-// that unix.UnixRights appears to make the assumption that fd is always int32,
-// so sizeof(fd) = 4.
-var oobSpace = unix.CmsgSpace(4)
-
-// RecvFd waits for a file descriptor to be sent over the given AF_UNIX
-// socket. The file name of the remote file descriptor will be recreated
-// locally (it is sent as non-auxiliary data in the same payload).
-func RecvFd(socket *os.File) (*os.File, error) {
-	// For some reason, unix.Recvmsg uses the length rather than the capacity
-	// when passing the msg_controllen and other attributes to recvmsg.  So we
-	// have to actually set the length.
-	name := make([]byte, MaxNameLen)
-	oob := make([]byte, oobSpace)
-
-	sockfd := socket.Fd()
-	n, oobn, _, _, err := unix.Recvmsg(int(sockfd), name, oob, 0)
-	if err != nil {
-		return nil, err
-	}
-
-	if n >= MaxNameLen || oobn != oobSpace {
-		return nil, fmt.Errorf("recvfd: incorrect number of bytes read (n=%d oobn=%d)", n, oobn)
-	}
-
-	// Truncate.
-	name = name[:n]
-	oob = oob[:oobn]
-
-	scms, err := unix.ParseSocketControlMessage(oob)
-	if err != nil {
-		return nil, err
-	}
-	if len(scms) != 1 {
-		return nil, fmt.Errorf("recvfd: number of SCMs is not 1: %d", len(scms))
-	}
-	scm := scms[0]
-
-	fds, err := unix.ParseUnixRights(&scm)
-	if err != nil {
-		return nil, err
-	}
-	if len(fds) != 1 {
-		return nil, fmt.Errorf("recvfd: number of fds is not 1: %d", len(fds))
-	}
-	fd := uintptr(fds[0])
-
-	return os.NewFile(fd, string(name)), nil
-}
-
-// SendFd sends a file descriptor over the given AF_UNIX socket. In
-// addition, the file.Name() of the given file will also be sent as
-// non-auxiliary data in the same payload (allowing to send contextual
-// information for a file descriptor).
-func SendFd(socket, file *os.File) error {
-	name := []byte(file.Name())
-	if len(name) >= MaxNameLen {
-		return fmt.Errorf("sendfd: filename too long: %s", file.Name())
-	}
-	oob := unix.UnixRights(int(file.Fd()))
-
-	return unix.Sendmsg(int(socket.Fd()), name, oob, nil, 0)
-}

vendor/github.com/opencontainers/runc/libcontainer/utils/utils.go

@@ -1,126 +0,0 @@
-package utils
-
-import (
-	"crypto/rand"
-	"encoding/hex"
-	"encoding/json"
-	"io"
-	"os"
-	"path/filepath"
-	"strings"
-	"syscall"
-	"unsafe"
-)
-
-const (
-	exitSignalOffset = 128
-)
-
-// GenerateRandomName returns a new name joined with a prefix.  This size
-// specified is used to truncate the randomly generated value
-func GenerateRandomName(prefix string, size int) (string, error) {
-	id := make([]byte, 32)
-	if _, err := io.ReadFull(rand.Reader, id); err != nil {
-		return "", err
-	}
-	if size > 64 {
-		size = 64
-	}
-	return prefix + hex.EncodeToString(id)[:size], nil
-}
-
-// ResolveRootfs ensures that the current working directory is
-// not a symlink and returns the absolute path to the rootfs
-func ResolveRootfs(uncleanRootfs string) (string, error) {
-	rootfs, err := filepath.Abs(uncleanRootfs)
-	if err != nil {
-		return "", err
-	}
-	return filepath.EvalSymlinks(rootfs)
-}
-
-// ExitStatus returns the correct exit status for a process based on if it
-// was signaled or exited cleanly
-func ExitStatus(status syscall.WaitStatus) int {
-	if status.Signaled() {
-		return exitSignalOffset + int(status.Signal())
-	}
-	return status.ExitStatus()
-}
-
-// WriteJSON writes the provided struct v to w using standard json marshaling
-func WriteJSON(w io.Writer, v interface{}) error {
-	data, err := json.Marshal(v)
-	if err != nil {
-		return err
-	}
-	_, err = w.Write(data)
-	return err
-}
-
-// CleanPath makes a path safe for use with filepath.Join. This is done by not
-// only cleaning the path, but also (if the path is relative) adding a leading
-// '/' and cleaning it (then removing the leading '/'). This ensures that a
-// path resulting from prepending another path will always resolve to lexically
-// be a subdirectory of the prefixed path. This is all done lexically, so paths
-// that include symlinks won't be safe as a result of using CleanPath.
-func CleanPath(path string) string {
-	// Deal with empty strings nicely.
-	if path == "" {
-		return ""
-	}
-
-	// Ensure that all paths are cleaned (especially problematic ones like
-	// "/../../../../../" which can cause lots of issues).
-	path = filepath.Clean(path)
-
-	// If the path isn't absolute, we need to do more processing to fix paths
-	// such as "../../../../<etc>/some/path". We also shouldn't convert absolute
-	// paths to relative ones.
-	if !filepath.IsAbs(path) {
-		path = filepath.Clean(string(os.PathSeparator) + path)
-		// This can't fail, as (by definition) all paths are relative to root.
-		path, _ = filepath.Rel(string(os.PathSeparator), path)
-	}
-
-	// Clean the path again for good measure.
-	return filepath.Clean(path)
-}
-
-// SearchLabels searches a list of key-value pairs for the provided key and
-// returns the corresponding value. The pairs must be separated with '='.
-func SearchLabels(labels []string, query string) string {
-	for _, l := range labels {
-		parts := strings.SplitN(l, "=", 2)
-		if len(parts) < 2 {
-			continue
-		}
-		if parts[0] == query {
-			return parts[1]
-		}
-	}
-	return ""
-}
-
-// Annotations returns the bundle path and user defined annotations from the
-// libcontainer state.  We need to remove the bundle because that is a label
-// added by libcontainer.
-func Annotations(labels []string) (bundle string, userAnnotations map[string]string) {
-	userAnnotations = make(map[string]string)
-	for _, l := range labels {
-		parts := strings.SplitN(l, "=", 2)
-		if len(parts) < 2 {
-			continue
-		}
-		if parts[0] == "bundle" {
-			bundle = parts[1]
-		} else {
-			userAnnotations[parts[0]] = parts[1]
-		}
-	}
-	return
-}
-
-func GetIntSize() int {
-	return int(unsafe.Sizeof(1))
-}

vendor/github.com/opencontainers/runc/libcontainer/utils/utils_unix.go

@@ -1,43 +0,0 @@
-// +build !windows
-
-package utils
-
-import (
-	"io/ioutil"
-	"os"
-	"strconv"
-	"syscall"
-)
-
-func CloseExecFrom(minFd int) error {
-	fdList, err := ioutil.ReadDir("/proc/self/fd")
-	if err != nil {
-		return err
-	}
-	for _, fi := range fdList {
-		fd, err := strconv.Atoi(fi.Name())
-		if err != nil {
-			// ignore non-numeric file names
-			continue
-		}
-
-		if fd < minFd {
-			// ignore descriptors lower than our specified minimum
-			continue
-		}
-
-		// intentionally ignore errors from syscall.CloseOnExec
-		syscall.CloseOnExec(fd)
-		// the cases where this might fail are basically file descriptors that have already been closed (including and especially the one that was created when ioutil.ReadDir did the "opendir" syscall)
-	}
-	return nil
-}
-
-// NewSockPair returns a new unix socket pair
-func NewSockPair(name string) (parent *os.File, child *os.File, err error) {
-	fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM|syscall.SOCK_CLOEXEC, 0)
-	if err != nil {
-		return nil, nil, err
-	}
-	return os.NewFile(uintptr(fds[1]), name+"-p"), os.NewFile(uintptr(fds[0]), name+"-c"), nil
-}