Add ArgsEscaped support for CRI

This commit adds supports for the ArgsEscaped
value for the image got from the dockerfile.
It is used to evaluate and process the image
entrypoint/cmd and container entrypoint/cmd
options got from the podspec.

Signed-off-by: Kirtana Ashok <Kirtana.Ashok@microsoft.com>

pkg/cri/opts/spec_nonwindows.go

@@ -0,0 +1,36 @@
+//go:build !windows
+
+/*
+   Copyright The containerd Authors.
+
+   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 opts
+
+import (
+	"context"
+
+	"github.com/containerd/containerd/containers"
+	"github.com/containerd/containerd/errdefs"
+	"github.com/containerd/containerd/oci"
+	imagespec "github.com/opencontainers/image-spec/specs-go/v1"
+	runtimespec "github.com/opencontainers/runtime-spec/specs-go"
+	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"
+)
+
+func WithProcessCommandLineOrArgsForWindows(config *runtime.ContainerConfig, image *imagespec.ImageConfig) oci.SpecOpts {
+	return func(ctx context.Context, client oci.Client, c *containers.Container, s *runtimespec.Spec) (err error) {
+		return errdefs.ErrNotImplemented
+	}
+}

pkg/cri/opts/spec_windows.go

@@ -0,0 +1,121 @@
+//go:build windows
+
+/*
+   Copyright The containerd Authors.
+
+   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 opts
+
+import (
+	"context"
+	"errors"
+	"strings"
+
+	"github.com/containerd/containerd/containers"
+	"github.com/containerd/containerd/oci"
+	imagespec "github.com/opencontainers/image-spec/specs-go/v1"
+	runtimespec "github.com/opencontainers/runtime-spec/specs-go"
+	"golang.org/x/sys/windows"
+	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"
+)
+
+func escapeAndCombineArgsWindows(args []string) string {
+	escaped := make([]string, len(args))
+	for i, a := range args {
+		escaped[i] = windows.EscapeArg(a)
+	}
+	return strings.Join(escaped, " ")
+}
+
+// WithProcessCommandLineOrArgsForWindows sets the process command line or process args on the spec based on the image
+// and runtime config
+// If image.ArgsEscaped field is set, this function sets the process command line and if not, it sets the
+// process args field
+func WithProcessCommandLineOrArgsForWindows(config *runtime.ContainerConfig, image *imagespec.ImageConfig) oci.SpecOpts {
+	if image.ArgsEscaped {
+		return func(ctx context.Context, client oci.Client, c *containers.Container, s *runtimespec.Spec) (err error) {
+			// firstArgFromImg is a flag that is returned to indicate that the first arg in the slice comes from either the
+			// image Entrypoint or Cmd. If the first arg instead comes from the container config (e.g. overriding the image values),
+			// it should be false. This is done to support the non-OCI ArgsEscaped field that Docker used to determine how the image
+			// entrypoint and cmd should be interpreted.
+			//
+			args, firstArgFromImg, err := getArgs(image.Entrypoint, image.Cmd, config.GetCommand(), config.GetArgs())
+			if err != nil {
+				return err
+			}
+
+			var cmdLine string
+			if image.ArgsEscaped && firstArgFromImg {
+				cmdLine = args[0]
+				if len(args) > 1 {
+					cmdLine += " " + escapeAndCombineArgsWindows(args[1:])
+				}
+			} else {
+				cmdLine = escapeAndCombineArgsWindows(args)
+			}
+
+			return oci.WithProcessCommandLine(cmdLine)(ctx, client, c, s)
+		}
+	}
+	// if ArgsEscaped is not set
+	return func(ctx context.Context, client oci.Client, c *containers.Container, s *runtimespec.Spec) (err error) {
+		args, _, err := getArgs(image.Entrypoint, image.Cmd, config.GetCommand(), config.GetArgs())
+		if err != nil {
+			return err
+		}
+		return oci.WithProcessArgs(args...)(ctx, client, c, s)
+	}
+}
+
+// getArgs is used to evaluate the overall args for the container by taking into account the image command and entrypoints
+// along with the container command and entrypoints specified through the podspec if any
+func getArgs(imgEntrypoint []string, imgCmd []string, ctrEntrypoint []string, ctrCmd []string) ([]string, bool, error) {
+	//nolint:dupword
+	// firstArgFromImg is a flag that is returned to indicate that the first arg in the slice comes from either the image
+	// Entrypoint or Cmd. If the first arg instead comes from the container config (e.g. overriding the image values),
+	// it should be false.
+	// Essentially this means firstArgFromImg should be true iff:
+	// Ctr entrypoint	ctr cmd		image entrypoint	image cmd	firstArgFromImg
+	// --------------------------------------------------------------------------------
+	//	nil				 nil			exists			 nil		  true
+	//  nil				 nil		    nil				 exists		  true
+
+	// This is needed to support the non-OCI ArgsEscaped field used by Docker. ArgsEscaped is used for
+	// Windows images to indicate that the command has already been escaped and should be
+	// used directly as the command line.
+	var firstArgFromImg bool
+	entrypoint, cmd := ctrEntrypoint, ctrCmd
+	// The following logic is migrated from https://github.com/moby/moby/blob/master/daemon/commit.go
+	// TODO(random-liu): Clearly define the commands overwrite behavior.
+	if len(entrypoint) == 0 {
+		// Copy array to avoid data race.
+		if len(cmd) == 0 {
+			cmd = append([]string{}, imgCmd...)
+			if len(imgCmd) > 0 {
+				firstArgFromImg = true
+			}
+		}
+		if entrypoint == nil {
+			entrypoint = append([]string{}, imgEntrypoint...)
+			if len(imgEntrypoint) > 0 || len(ctrCmd) == 0 {
+				firstArgFromImg = true
+			}
+		}
+	}
+	if len(entrypoint) == 0 && len(cmd) == 0 {
+		return nil, false, errors.New("no command specified")
+	}
+	return append(entrypoint, cmd...), firstArgFromImg, nil
+}

pkg/cri/opts/spec_windows_opts.go

@@ -24,12 +24,11 @@ import (
 	"sort"
 	"strings"
 
-	runtimespec "github.com/opencontainers/runtime-spec/specs-go"
-	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"
-
 	"github.com/containerd/containerd/containers"
 	"github.com/containerd/containerd/oci"
 	osinterface "github.com/containerd/containerd/pkg/os"
+	runtimespec "github.com/opencontainers/runtime-spec/specs-go"
+	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"
 )
 
 // namedPipePath returns true if the given path is to a named pipe.