refactor(backend): rename OpenFlare directory to lowercase openflare

backend/openflare/plugins/agent/runtimeuser/runtimeuser.go

@@ -0,0 +1,195 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package runtimeuser defines the shared OS account used by the agent process
+// and OpenResty worker processes so file ownership stays aligned.
+package runtimeuser
+
+import (
+	"errors"
+	"fmt"
+	"log/slog"
+	"os"
+	"os/user"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	openrestyrender "Wavelet/openflare/share/render/openresty"
+)
+
+// Name is the dedicated service account shared by the agent and OpenResty workers.
+const Name = openrestyrender.OpenFlareRuntimeUser
+
+const (
+	// DefaultDirPerm is the normalized permission for runtime directories.
+	DefaultDirPerm = 0o755
+	// DefaultFilePerm is the normalized permission for runtime files.
+	DefaultFilePerm = 0o644
+)
+
+// Account holds the resolved UID/GID for Name on the current host.
+type Account struct {
+	Name string
+	UID  int
+	GID  int
+}
+
+// Lookup resolves the runtime account on the current host.
+func Lookup() (*Account, error) {
+	record, err := user.Lookup(Name)
+	if err != nil {
+		return nil, fmt.Errorf("lookup %s: %w", Name, err)
+	}
+	uid, err := strconv.Atoi(record.Uid)
+	if err != nil {
+		return nil, fmt.Errorf("parse uid for %s: %w", Name, err)
+	}
+	gid, err := strconv.Atoi(record.Gid)
+	if err != nil {
+		return nil, fmt.Errorf("parse gid for %s: %w", Name, err)
+	}
+	return &Account{Name: Name, UID: uid, GID: gid}, nil
+}
+
+// CurrentEUID returns the effective UID of the current process.
+func CurrentEUID() int {
+	return os.Geteuid()
+}
+
+// IsRuntimeUser reports whether the current process runs as Name.
+func IsRuntimeUser() bool {
+	account, err := Lookup()
+	if err != nil {
+		return false
+	}
+	return os.Geteuid() == account.UID
+}
+
+// EnsureProcessUser drops from root to Name when possible so the agent writes
+// files with the same ownership OpenResty workers read.
+func EnsureProcessUser() error {
+	account, err := Lookup()
+	if err != nil {
+		slog.Warn("runtime user unavailable, agent continues as current user", "user", Name, "euid", os.Geteuid(), "error", err)
+		return nil
+	}
+	if os.Geteuid() == account.UID {
+		slog.Info("agent running as runtime user", "user", Name, "uid", account.UID)
+		return nil
+	}
+	if os.Geteuid() != 0 {
+		slog.Warn("agent is not running as runtime user", "expected", Name, "euid", os.Geteuid())
+		return nil
+	}
+	if dropErr := dropToImpl(account); dropErr != nil {
+		return dropErr
+	}
+	slog.Info("agent dropped privileges to runtime user", "user", Name, "uid", account.UID)
+	return nil
+}
+
+// EnsurePathOwnership makes root and its ancestors traversable, assigns runtime
+// ownership when running as root, and normalizes directory/file modes.
+func EnsurePathOwnership(root string, dirPerm os.FileMode, filePerm os.FileMode) error {
+	root = filepath.Clean(strings.TrimSpace(root))
+	if root == "" || root == "." {
+		return nil
+	}
+	if err := ensureWorldTraversablePath(root); err != nil {
+		return err
+	}
+	if _, statErr := os.Stat(root); os.IsNotExist(statErr) {
+		return nil
+	}
+	account, lookupErr := Lookup()
+	if lookupErr != nil {
+		var unknown user.UnknownUserError
+		if errors.As(lookupErr, &unknown) {
+			return ensureModesOnly(root, dirPerm, filePerm)
+		}
+		return lookupErr
+	}
+	return applyOwnershipAndModes(root, account, dirPerm, filePerm)
+}
+
+var dropToImpl = func(account *Account) error {
+	return fmt.Errorf("drop to runtime user %s is not supported on this platform", account.Name)
+}
+
+func ensureWorldTraversablePath(targetDir string) error {
+	const maxDepth = 12
+	current := filepath.Clean(strings.TrimSpace(targetDir))
+	if current == "" || current == "." {
+		return nil
+	}
+	for range maxDepth {
+		if err := os.Chmod(current, DefaultDirPerm); err != nil { //nolint:gosec // parent dirs must be traversable by the runtime user
+			if os.IsNotExist(err) || os.IsPermission(err) {
+				break
+			}
+			return fmt.Errorf("chmod %s: %w", current, err)
+		}
+		parent := filepath.Dir(current)
+		if parent == current {
+			break
+		}
+		current = parent
+	}
+	return nil
+}
+
+func applyOwnershipAndModes(root string, account *Account, dirPerm os.FileMode, filePerm os.FileMode) error {
+	return filepath.WalkDir(root, func(path string, entry os.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		info, err := entry.Info()
+		if err != nil {
+			return err
+		}
+		if os.Geteuid() == 0 {
+			if chownErr := os.Chown(path, account.UID, account.GID); chownErr != nil && !os.IsNotExist(chownErr) { //nolint:gosec // path is under managed root walk
+				return fmt.Errorf("chown %s: %w", path, chownErr)
+			}
+		}
+		if entry.IsDir() {
+			if chmodErr := os.Chmod(path, dirPerm); chmodErr != nil && !os.IsNotExist(chmodErr) { //nolint:gosec // path is under managed root walk
+				return fmt.Errorf("chmod dir %s: %w", path, chmodErr)
+			}
+			return nil
+		}
+		if !info.Mode().IsRegular() {
+			return nil
+		}
+		if chmodErr := os.Chmod(path, filePerm); chmodErr != nil && !os.IsNotExist(chmodErr) { //nolint:gosec // path is under managed root walk
+			return fmt.Errorf("chmod file %s: %w", path, chmodErr)
+		}
+		return nil
+	})
+}
+
+func ensureModesOnly(root string, dirPerm os.FileMode, filePerm os.FileMode) error {
+	return filepath.WalkDir(root, func(path string, entry os.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		info, err := entry.Info()
+		if err != nil {
+			return err
+		}
+		if entry.IsDir() {
+			if chmodErr := os.Chmod(path, dirPerm); chmodErr != nil && !os.IsNotExist(chmodErr) { //nolint:gosec // path is under managed root walk
+				return fmt.Errorf("chmod dir %s: %w", path, chmodErr)
+			}
+			return nil
+		}
+		if !info.Mode().IsRegular() {
+			return nil
+		}
+		if chmodErr := os.Chmod(path, filePerm); chmodErr != nil && !os.IsNotExist(chmodErr) { //nolint:gosec // path is under managed root walk
+			return fmt.Errorf("chmod file %s: %w", path, chmodErr)
+		}
+		return nil
+	})
+}