Add workspace filesystem helpers

2026-07-08 02:23:20 +00:00
parent a024492dbf
commit 93653cccb8
5 changed files with 468 additions and 0 deletions
--- a/internal/core/workspace/files.go
+++ b/internal/core/workspace/files.go
@@ -0,0 +1,114 @@
+package workspace
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+func SafePath(root string, name string) (string, error) {
+	root = strings.TrimSpace(root)
+	if root == "" {
+		return "", fmt.Errorf("workspace root must not be empty")
+	}
+	name = strings.TrimSpace(name)
+	if name == "" {
+		return "", fmt.Errorf("workspace artifact name must not be empty")
+	}
+	if strings.Contains(name, `\`) {
+		return "", fmt.Errorf("workspace artifact name %q must use slash-separated relative paths", name)
+	}
+	if path.IsAbs(name) || filepath.IsAbs(name) {
+		return "", fmt.Errorf("workspace artifact name %q must be relative", name)
+	}
+	if name == "." || strings.Contains(name, "..") {
+		return "", fmt.Errorf("workspace artifact name %q must not contain ..", name)
+	}
+	cleaned := path.Clean(name)
+	if cleaned != name {
+		return "", fmt.Errorf("workspace artifact name %q must be clean", name)
+	}
+
+	absRoot, err := filepath.Abs(root)
+	if err != nil {
+		return "", fmt.Errorf("resolve workspace root %q: %w", root, err)
+	}
+	target, err := filepath.Abs(filepath.Join(absRoot, filepath.FromSlash(cleaned)))
+	if err != nil {
+		return "", fmt.Errorf("resolve workspace artifact %q: %w", name, err)
+	}
+	rel, err := filepath.Rel(absRoot, target)
+	if err != nil {
+		return "", fmt.Errorf("resolve workspace artifact %q: %w", name, err)
+	}
+	if rel == "." || rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) {
+		return "", fmt.Errorf("workspace artifact name %q resolves outside workspace root", name)
+	}
+	return target, nil
+}
+
+func WriteJSON(root string, name string, payload any) error {
+	target, err := SafePath(root, name)
+	if err != nil {
+		return err
+	}
+	data, err := json.MarshalIndent(payload, "", "  ")
+	if err != nil {
+		return fmt.Errorf("marshal workspace artifact %q: %w", name, err)
+	}
+	data = append(data, '\n')
+	if err := writeFileAtomic(target, data, 0o644); err != nil {
+		return fmt.Errorf("write workspace artifact %q: %w", name, err)
+	}
+	return nil
+}
+
+func WriteBytes(root string, name string, data []byte) error {
+	target, err := SafePath(root, name)
+	if err != nil {
+		return err
+	}
+	if err := writeFileAtomic(target, data, 0o644); err != nil {
+		return fmt.Errorf("write workspace artifact %q: %w", name, err)
+	}
+	return nil
+}
+
+func writeFileAtomic(target string, data []byte, perm os.FileMode) error {
+	dir := filepath.Dir(target)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return err
+	}
+
+	temp, err := os.CreateTemp(dir, "."+filepath.Base(target)+".tmp-*")
+	if err != nil {
+		return err
+	}
+	tempPath := temp.Name()
+	removeTemp := true
+	defer func() {
+		if removeTemp {
+			_ = os.Remove(tempPath)
+		}
+	}()
+
+	if _, err := temp.Write(data); err != nil {
+		_ = temp.Close()
+		return err
+	}
+	if err := temp.Chmod(perm); err != nil {
+		_ = temp.Close()
+		return err
+	}
+	if err := temp.Close(); err != nil {
+		return err
+	}
+	if err := os.Rename(tempPath, target); err != nil {
+		return err
+	}
+	removeTemp = false
+	return nil
+}