607888ce29
The OCI image specification includes a `StopSignal` field in the image configuration, denoting the system call signal to be sent to the container to exit. This commit adds a new `WithImageStopSignal` container option that can be used for storing the `StopSignal` field as a label on the container. This commit also adjusts `ctr run` to call `WithImageStopSignal` and `ctr tasks kill` to send the signal stored in that label by default. Signed-off-by: Samuel Karp <skarp@amazon.com>
106 lines
2.8 KiB
Go
106 lines
2.8 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package containerd
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import (
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"context"
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"encoding/json"
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"fmt"
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"strconv"
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"strings"
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"syscall"
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"github.com/containerd/containerd/content"
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"github.com/containerd/containerd/images"
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"github.com/opencontainers/image-spec/specs-go/v1"
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)
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// StopSignalLabel is a well-known containerd label for storing the stop
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// signal specified in the OCI image config
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const StopSignalLabel = "io.containerd.image.config.stop-signal"
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// GetStopSignal retrieves the container stop signal, specified by the
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// well-known containerd label (StopSignalLabel)
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func GetStopSignal(ctx context.Context, container Container, defaultSignal syscall.Signal) (syscall.Signal, error) {
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labels, err := container.Labels(ctx)
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if err != nil {
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return -1, err
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}
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if stopSignal, ok := labels[StopSignalLabel]; ok {
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return ParseSignal(stopSignal)
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}
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return defaultSignal, nil
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}
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// GetOCIStopSignal retrieves the stop signal specified in the OCI image config
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func GetOCIStopSignal(ctx context.Context, image Image, defaultSignal string) (string, error) {
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_, err := ParseSignal(defaultSignal)
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if err != nil {
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return "", err
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}
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ic, err := image.Config(ctx)
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if err != nil {
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return "", err
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}
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var (
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ociimage v1.Image
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config v1.ImageConfig
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)
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switch ic.MediaType {
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case v1.MediaTypeImageConfig, images.MediaTypeDockerSchema2Config:
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p, err := content.ReadBlob(ctx, image.ContentStore(), ic)
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if err != nil {
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return "", err
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}
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if err := json.Unmarshal(p, &ociimage); err != nil {
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return "", err
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}
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config = ociimage.Config
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default:
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return "", fmt.Errorf("unknown image config media type %s", ic.MediaType)
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}
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if config.StopSignal == "" {
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return defaultSignal, nil
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}
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return config.StopSignal, nil
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}
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// ParseSignal parses a given string into a syscall.Signal
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// it checks that the signal exists in the platform-appropriate signalMap
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func ParseSignal(rawSignal string) (syscall.Signal, error) {
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s, err := strconv.Atoi(rawSignal)
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if err == nil {
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sig := syscall.Signal(s)
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for _, msig := range signalMap {
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if sig == msig {
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return sig, nil
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}
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}
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return -1, fmt.Errorf("unknown signal %q", rawSignal)
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}
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signal, ok := signalMap[strings.TrimPrefix(strings.ToUpper(rawSignal), "SIG")]
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if !ok {
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return -1, fmt.Errorf("unknown signal %q", rawSignal)
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}
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return signal, nil
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}
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