feat: init firecracker

internal/firecracker/paths.go

@@ -0,0 +1,45 @@
+package firecracker
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+)
+
+const defaultSocketName = "api.socket"
+
+type machinePaths struct {
+	BaseDir        string
+	JailerBaseDir  string
+	ChrootRootDir  string
+	SocketName     string
+	SocketPath     string
+	FirecrackerBin string
+}
+
+func buildMachinePaths(rootDir string, id MachineID, firecrackerBinaryPath string) (machinePaths, error) {
+	rootDir = strings.TrimSpace(rootDir)
+	if rootDir == "" {
+		return machinePaths{}, fmt.Errorf("root dir is required")
+	}
+	if strings.TrimSpace(string(id)) == "" {
+		return machinePaths{}, fmt.Errorf("machine id is required")
+	}
+	binName := filepath.Base(strings.TrimSpace(firecrackerBinaryPath))
+	if binName == "." || binName == string(filepath.Separator) || binName == "" {
+		return machinePaths{}, fmt.Errorf("firecracker binary path is required")
+	}
+
+	baseDir := filepath.Join(rootDir, "machines", string(id))
+	jailerBaseDir := filepath.Join(baseDir, "jailer")
+	chrootRootDir := filepath.Join(jailerBaseDir, binName, string(id), "root")
+
+	return machinePaths{
+		BaseDir:        baseDir,
+		JailerBaseDir:  jailerBaseDir,
+		ChrootRootDir:  chrootRootDir,
+		SocketName:     defaultSocketName,
+		SocketPath:     filepath.Join(chrootRootDir, defaultSocketName),
+		FirecrackerBin: binName,
+	}, nil
+}