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package hst
import (
"crypto/rand"
"encoding/binary"
"encoding/hex"
"errors"
"fmt"
"time"
)
// An ID is a unique identifier held by a running hakurei container.
type ID [16]byte
// ErrIdentifierLength is returned when encountering a [hex] representation of [ID] with unexpected length.
var ErrIdentifierLength = errors.New("identifier string has unexpected length")
// IdentifierDecodeError is returned by [ID.UnmarshalText] to provide relevant error descriptions.
type IdentifierDecodeError struct{ Err error }
func (e IdentifierDecodeError) Unwrap() error { return e.Err }
func (e IdentifierDecodeError) Error() string {
var invalidByteError hex.InvalidByteError
switch {
case errors.As(e.Err, &invalidByteError):
return fmt.Sprintf("got invalid byte %#U in identifier", rune(invalidByteError))
case errors.Is(e.Err, hex.ErrLength):
return "odd length identifier hex string"
default:
return e.Err.Error()
}
}
// String returns the [hex] string representation of [ID].
func (a *ID) String() string { return hex.EncodeToString(a[:]) }
// CreationTime returns the point in time [ID] was created.
func (a *ID) CreationTime() time.Time {
return time.Unix(0, int64(binary.BigEndian.Uint64(a[:8]))).UTC()
}
// NewInstanceID creates a new unique [ID].
func NewInstanceID(id *ID) error { return newInstanceID(id, uint64(time.Now().UnixNano())) }
// newInstanceID creates a new unique [ID] with the specified timestamp.
func newInstanceID(id *ID, p uint64) error {
binary.BigEndian.PutUint64(id[:8], p)
_, err := rand.Read(id[8:])
return err
}
// MarshalText encodes the [hex] representation of [ID].
func (a *ID) MarshalText() (text []byte, err error) {
text = make([]byte, hex.EncodedLen(len(a)))
hex.Encode(text, a[:])
return
}
// UnmarshalText decodes a [hex] representation of [ID].
func (a *ID) UnmarshalText(text []byte) error {
dl := hex.DecodedLen(len(text))
if dl != len(a) {
return IdentifierDecodeError{ErrIdentifierLength}
}
_, err := hex.Decode(a[:], text)
if err == nil {
return nil
}
return IdentifierDecodeError{err}
}
// A State describes a running hakurei container.
type State struct {
// Unique instance id, created by [NewInstanceID].
ID ID `json:"instance"`
// Monitoring process pid. Runs as the priv user.
PID int `json:"pid"`
// Shim process pid. Runs as the target user.
ShimPID int `json:"shim_pid"`
// Configuration used to start the container.
Config *Config `json:"config"`
// Point in time the shim process was created.
Time time.Time `json:"time"`
}
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