mirror of https://github.com/k3s-io/k3s
75 lines
1.9 KiB
Go
75 lines
1.9 KiB
Go
// +build linux
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package fs2
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import (
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stdErrors "errors"
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"os"
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"strings"
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"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
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"github.com/opencontainers/runc/libcontainer/configs"
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"github.com/pkg/errors"
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"golang.org/x/sys/unix"
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)
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func setFreezer(dirPath string, state configs.FreezerState) error {
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if err := supportsFreezer(dirPath); err != nil {
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// We can ignore this request as long as the user didn't ask us to
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// freeze the container (since without the freezer cgroup, that's a
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// no-op).
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if state == configs.Undefined || state == configs.Thawed {
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return nil
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}
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return errors.Wrap(err, "freezer not supported")
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}
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var stateStr string
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switch state {
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case configs.Undefined:
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return nil
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case configs.Frozen:
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stateStr = "1"
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case configs.Thawed:
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stateStr = "0"
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default:
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return errors.Errorf("invalid freezer state %q requested", state)
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}
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if err := fscommon.WriteFile(dirPath, "cgroup.freeze", stateStr); err != nil {
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return err
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}
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// Confirm that the cgroup did actually change states.
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if actualState, err := getFreezer(dirPath); err != nil {
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return err
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} else if actualState != state {
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return errors.Errorf(`expected "cgroup.freeze" to be in state %q but was in %q`, state, actualState)
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}
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return nil
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}
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func supportsFreezer(dirPath string) error {
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_, err := fscommon.ReadFile(dirPath, "cgroup.freeze")
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return err
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}
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func getFreezer(dirPath string) (configs.FreezerState, error) {
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state, err := fscommon.ReadFile(dirPath, "cgroup.freeze")
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if err != nil {
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// If the kernel is too old, then we just treat the freezer as being in
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// an "undefined" state.
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if os.IsNotExist(err) || stdErrors.Is(err, unix.ENODEV) {
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err = nil
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}
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return configs.Undefined, err
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}
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switch strings.TrimSpace(state) {
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case "0":
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return configs.Thawed, nil
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case "1":
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return configs.Frozen, nil
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default:
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return configs.Undefined, errors.Errorf(`unknown "cgroup.freeze" state: %q`, state)
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}
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}
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