Add support for setting user

client/client_test.go

@@ -36,6 +36,7 @@ func TestClientIntegration(t *testing.T) {
 		testBuildHTTPSource,
 		testBuildPushAndValidate,
 		testResolveAndHosts,
+		testUser,
 	})
 }
 
@@ -200,6 +201,59 @@ func testResolveAndHosts(t *testing.T, sb integration.Sandbox) {
 
 }
 
+func testUser(t *testing.T, sb integration.Sandbox) {
+	requiresLinux(t)
+	t.Parallel()
+	c, err := New(sb.Address())
+	require.NoError(t, err)
+	defer c.Close()
+
+	st := llb.Image("busybox:latest").Run(llb.Shlex(`sh -c "mkdir -m 0777 /wd"`))
+
+	run := func(user, cmd string) {
+		st = st.Run(llb.Shlex(cmd), llb.Dir("/wd"), llb.User(user))
+	}
+
+	run("daemon", `sh -c "id -nu > user"`)
+	run("daemon:daemon", `sh -c "id -ng > group"`)
+	run("daemon:nogroup", `sh -c "id -ng > nogroup"`)
+	run("1:1", `sh -c "id -g > userone"`)
+
+	st = st.Run(llb.Shlex("cp -a /wd/. /out/"))
+	out := st.AddMount("/out", llb.Scratch())
+
+	def, err := out.Marshal()
+	require.NoError(t, err)
+
+	destDir, err := ioutil.TempDir("", "buildkit")
+	require.NoError(t, err)
+	defer os.RemoveAll(destDir)
+
+	err = c.Solve(context.TODO(), def, SolveOpt{
+		Exporter: ExporterLocal,
+		ExporterAttrs: map[string]string{
+			"output": destDir,
+		},
+	}, nil)
+	require.NoError(t, err)
+
+	dt, err := ioutil.ReadFile(filepath.Join(destDir, "user"))
+	require.NoError(t, err)
+	require.Contains(t, string(dt), "daemon")
+
+	dt, err = ioutil.ReadFile(filepath.Join(destDir, "group"))
+	require.NoError(t, err)
+	require.Contains(t, string(dt), "daemon")
+
+	dt, err = ioutil.ReadFile(filepath.Join(destDir, "nogroup"))
+	require.NoError(t, err)
+	require.Contains(t, string(dt), "nogroup")
+
+	dt, err = ioutil.ReadFile(filepath.Join(destDir, "userone"))
+	require.NoError(t, err)
+	require.Contains(t, string(dt), "1")
+}
+
 func testBuildPushAndValidate(t *testing.T, sb integration.Sandbox) {
 	requiresLinux(t)
 	t.Parallel()

client/llb/exec.go

@@ -12,6 +12,7 @@ type Meta struct {
 	Args []string
 	Env  EnvList
 	Cwd  string
+	User string
 }
 
 func NewExecOp(root Output, meta Meta, readOnly bool, md OpMetadata) *ExecOp {
@@ -110,6 +111,7 @@ func (e *ExecOp) Marshal() ([]byte, *OpMetadata, error) {
 			Args: e.meta.Args,
 			Env:  e.meta.Env.ToArray(),
 			Cwd:  e.meta.Cwd,
+			User: e.meta.User,
 		},
 	}
 
@@ -271,6 +273,12 @@ func AddEnvf(key, value string, v ...interface{}) RunOption {
 	})
 }
 
+func User(str string) RunOption {
+	return runOptionFunc(func(ei *ExecInfo) {
+		ei.State = ei.State.User(str)
+	})
+}
+
 func Dir(str string) RunOption {
 	return Dirf(str)
 }

client/llb/meta.go

@@ -12,6 +12,7 @@ var (
 	keyArgs = contextKeyT("llb.exec.args")
 	keyDir  = contextKeyT("llb.exec.dir")
 	keyEnv  = contextKeyT("llb.exec.env")
+	keyUser = contextKeyT("llb.exec.user")
 )
 
 func addEnv(key, value string) StateOption {
@@ -42,6 +43,12 @@ func dirf(str string, v ...interface{}) StateOption {
 	}
 }
 
+func user(str string) StateOption {
+	return func(s State) State {
+		return s.WithValue(keyUser, str)
+	}
+}
+
 func reset(s_ State) StateOption {
 	return func(s State) State {
 		s = NewState(s.Output())
@@ -74,6 +81,14 @@ func getArgs(s State) []string {
 	return nil
 }
 
+func getUser(s State) string {
+	v := s.Value(keyUser)
+	if v != nil {
+		return v.(string)
+	}
+	return ""
+}
+
 func args(args ...string) StateOption {
 	return func(s State) State {
 		return s.WithValue(keyArgs, args)

client/llb/state.go

@@ -129,6 +129,7 @@ func (s State) Run(ro ...RunOption) ExecState {
 		Args: getArgs(ei.State),
 		Cwd:  getDir(ei.State),
 		Env:  getEnv(ei.State),
+		User: getUser(ei.State),
 	}
 
 	exec := NewExecOp(s.Output(), meta, ei.ReadonlyRootFS, ei.Metadata())
@@ -173,6 +174,10 @@ func (s State) Reset(s2 State) State {
 	return reset(s2)(s)
 }
 
+func (s State) User(v string) State {
+	return user(v)(s)
+}
+
 func (s State) With(so ...StateOption) State {
 	for _, o := range so {
 		s = o(s)

executor/containerdexecutor/executor.go

@@ -7,10 +7,12 @@ import (
 
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/cio"
+	containerdoci "github.com/containerd/containerd/oci"
 	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/executor"
 	"github.com/moby/buildkit/executor/oci"
 	"github.com/moby/buildkit/identity"
+	"github.com/moby/buildkit/snapshot"
 	"github.com/pkg/errors"
 	"golang.org/x/net/context"
 )
@@ -40,16 +42,31 @@ func (w containerdExecutor) Exec(ctx context.Context, meta executor.Meta, root c
 		return err
 	}
 
-	spec, cleanup, err := oci.GenerateSpec(ctx, meta, mounts, id, resolvConf, hostsFile)
+	rootMounts, err := root.Mount(ctx, false)
 	if err != nil {
 		return err
 	}
-	defer cleanup()
 
-	rootMounts, err := root.Mount(ctx, false)
+	uid, gid, err := oci.ParseUser(meta.User)
+	if err != nil {
+		lm := snapshot.LocalMounter(rootMounts)
+		rootfsPath, err := lm.Mount()
+		if err != nil {
+			return err
+		}
+		uid, gid, err = oci.GetUser(ctx, rootfsPath, meta.User)
+		if err != nil {
+			lm.Unmount()
+			return err
+		}
+		lm.Unmount()
+	}
+
+	spec, cleanup, err := oci.GenerateSpec(ctx, meta, mounts, id, resolvConf, hostsFile, containerdoci.WithUIDGID(uid, gid))
 	if err != nil {
 		return err
 	}
+	defer cleanup()
 
 	container, err := w.client.NewContainer(ctx, id,
 		containerd.WithSpec(spec),

executor/oci/spec_unix.go

@@ -21,21 +21,24 @@ import (
 // Ideally we don't have to import whole containerd just for the default spec
 
 // GenerateSpec generates spec using containerd functionality.
-func GenerateSpec(ctx context.Context, meta executor.Meta, mounts []executor.Mount, id string, resolvConf, hostsFile string) (*specs.Spec, func(), error) {
+func GenerateSpec(ctx context.Context, meta executor.Meta, mounts []executor.Mount, id, resolvConf, hostsFile string, opts ...oci.SpecOpts) (*specs.Spec, func(), error) {
 	c := &containers.Container{
 		ID: id,
 	}
 	_, ok := namespaces.Namespace(ctx)
 	if !ok {
 		ctx = namespaces.WithNamespace(ctx, "buildkit")
 	}
-	// Note that containerd.GenerateSpec is namespaced so as to make
-	// specs.Linux.CgroupsPath namespaced
-	s, err := oci.GenerateSpec(ctx, nil, c,
+
+	opts = append(opts,
 		oci.WithHostNamespace(specs.NetworkNamespace),
 		withROBind(resolvConf, "/etc/resolv.conf"),
 		withROBind(hostsFile, "/etc/hosts"),
 	)
+
+	// Note that containerd.GenerateSpec is namespaced so as to make
+	// specs.Linux.CgroupsPath namespaced
+	s, err := oci.GenerateSpec(ctx, nil, c, opts...)
 	if err != nil {
 		return nil, nil, err
 	}

executor/oci/user.go

@@ -0,0 +1,86 @@
+package oci
+
+import (
+	"context"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/containerd/containerd/fs"
+	"github.com/opencontainers/runc/libcontainer/user"
+)
+
+func GetUser(ctx context.Context, root, username string) (uint32, uint32, error) {
+	// fast path from uid/gid
+	if uid, gid, err := ParseUser(username); err == nil {
+		return uid, gid, nil
+	}
+
+	passwdPath, err := user.GetPasswdPath()
+	if err != nil {
+		return 0, 0, err
+	}
+	groupPath, err := user.GetGroupPath()
+	if err != nil {
+		return 0, 0, err
+	}
+	passwdFile, err := openUserFile(root, passwdPath)
+	if err == nil {
+		defer passwdFile.Close()
+	}
+	groupFile, err := openUserFile(root, groupPath)
+	if err == nil {
+		defer groupFile.Close()
+	}
+
+	execUser, err := user.GetExecUser(username, nil, passwdFile, groupFile)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	return uint32(execUser.Uid), uint32(execUser.Gid), nil
+}
+
+func ParseUser(str string) (uid uint32, gid uint32, err error) {
+	if str == "" {
+		return 0, 0, nil
+	}
+	parts := strings.SplitN(str, ":", 2)
+	for i, v := range parts {
+		switch i {
+		case 0:
+			uid, err = parseUID(v)
+			if err != nil {
+				return 0, 0, err
+			}
+			if len(parts) == 1 {
+				gid = uid
+			}
+		case 1:
+			gid, err = parseUID(v)
+			if err != nil {
+				return 0, 0, err
+			}
+		}
+	}
+	return
+}
+
+func openUserFile(root, p string) (*os.File, error) {
+	p, err := fs.RootPath(root, p)
+	if err != nil {
+		return nil, err
+	}
+	return os.Open(p)
+}
+
+func parseUID(str string) (uint32, error) {
+	if str == "root" {
+		return 0, nil
+	}
+	uid, err := strconv.ParseUint(str, 10, 32)
+	if err != nil {
+		return 0, err
+	}
+	return uint32(uid), nil
+}

executor/runcexecutor/executor.go

@@ -9,6 +9,7 @@ import (
 	"syscall"
 
 	"github.com/containerd/containerd/mount"
+	containerdoci "github.com/containerd/containerd/oci"
 	runc "github.com/containerd/go-runc"
 	"github.com/docker/docker/pkg/symlink"
 	"github.com/moby/buildkit/cache"
@@ -82,21 +83,27 @@ func (w *runcExecutor) Exec(ctx context.Context, meta executor.Meta, root cache.
 	if err := os.Mkdir(rootFSPath, 0700); err != nil {
 		return err
 	}
+	if err := mount.All(rootMount, rootFSPath); err != nil {
+		return err
+	}
+	defer mount.Unmount(rootFSPath, 0)
+
+	uid, gid, err := oci.GetUser(ctx, rootFSPath, meta.User)
+	if err != nil {
+		return err
+	}
+
 	f, err := os.Create(filepath.Join(bundle, "config.json"))
 	if err != nil {
 		return err
 	}
 	defer f.Close()
-	spec, cleanup, err := oci.GenerateSpec(ctx, meta, mounts, id, resolvConf, hostsFile)
+	spec, cleanup, err := oci.GenerateSpec(ctx, meta, mounts, id, resolvConf, hostsFile, containerdoci.WithUIDGID(uid, gid))
 	if err != nil {
 		return err
 	}
 	defer cleanup()
 
-	if err := mount.All(rootMount, rootFSPath); err != nil {
-		return err
-	}
-	defer mount.Unmount(rootFSPath, 0)
 	spec.Root.Path = rootFSPath
 	if _, ok := root.(cache.ImmutableRef); ok { // TODO: pass in with mount, not ref type
 		spec.Root.Readonly = true

frontend/dockerfile/dockerfile2llb/convert.go

@@ -477,6 +477,7 @@ func dispatchExpose(d *dispatchState, c *instructions.ExposeCommand, shlex *Shel
 	return commitToHistory(&d.image, fmt.Sprintf("EXPOSE %v", ps), false, nil)
 }
 func dispatchUser(d *dispatchState, c *instructions.UserCommand, commit bool) error {
+	d.state = d.state.User(c.User)
 	d.image.Config.User = c.User
 	if commit {
 		return commitToHistory(&d.image, fmt.Sprintf("USER %v", c.User), false, nil)