Reset master to testing content

internal/tentacle/local.go

@@ -0,0 +1,68 @@
+package tentacle
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// LoadLocalSpecs reads an explicit development launch list, not a manifest or
+// installation catalog. It does not execute code or discover directories.
+func LoadLocalSpecs(path string) ([]Spec, error) {
+	file, err := os.OpenFile(path, os.O_RDONLY|syscall.O_NONBLOCK, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+	info, err := file.Stat()
+	if err != nil {
+		return nil, err
+	}
+	if !info.Mode().IsRegular() {
+		return nil, fmt.Errorf("local tentacle list must be a regular file")
+	}
+	data, err := io.ReadAll(io.LimitReader(file, MaxFrameBytes+1))
+	if err != nil {
+		return nil, err
+	}
+	if len(data) > MaxFrameBytes {
+		return nil, ErrLimit
+	}
+	if err := validate_json(data); err != nil {
+		return nil, err
+	}
+	var specs []Spec
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(&specs); err != nil {
+		return nil, err
+	}
+	if len(specs) > DefaultLimits().Processes {
+		return nil, ErrLimit
+	}
+	seen := make(map[string]bool)
+	for _, spec := range specs {
+		if err := validate_spec(spec); err != nil {
+			return nil, err
+		}
+		if seen[spec.ID] {
+			return nil, fmt.Errorf("duplicate local tentacle ID")
+		}
+		seen[spec.ID] = true
+	}
+	return specs, nil
+}
+
+// DelegatedParent reads an explicitly configured optional cgroup parent.
+// It does not inspect init-system naming conventions or move the reader.
+func DelegatedParent() (string, error) {
+	parent := os.Getenv("CTHULHU_TENTACLE_CGROUP_PARENT")
+	if !filepath.IsAbs(parent) || filepath.Clean(parent) != parent {
+		return "", fmt.Errorf("%w: configure CTHULHU_TENTACLE_CGROUP_PARENT with an absolute delegated cgroup v2 directory", ErrContainment)
+	}
+	return parent, nil
+}