split ffmpeg install helpers

internal/service/ffmpeg_install_archive.go

@@ -0,0 +1,202 @@
+package service
+
+import (
+	"archive/zip"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"go.uber.org/zap"
+)
+
+const (
+	maxFFmpegZipEntryBytes = int64(2 << 30)
+	maxFFmpegZipTotalBytes = int64(4 << 30)
+)
+
+// unzip 解压 ZIP 文件。
+func unzip(log *zap.Logger, zipPath, destDir string) error {
+	if err := os.MkdirAll(destDir, 0o750); err != nil {
+		return err
+	}
+	destRoot, err := filepath.Abs(destDir)
+	if err != nil {
+		return err
+	}
+	reader, err := zip.OpenReader(zipPath)
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+	var totalWritten int64
+	for _, file := range reader.File {
+		if file.UncompressedSize64 > uint64(maxFFmpegZipEntryBytes) {
+			return fmt.Errorf("zip entry too large: %s", file.Name)
+		}
+		target, err := safeZipTarget(destRoot, file.Name)
+		if err != nil {
+			return err
+		}
+		info := file.FileInfo()
+		if info.Mode()&os.ModeSymlink != 0 {
+			log.Warn("跳过 ZIP 符号链接", zap.String("name", file.Name))
+			continue
+		}
+		if info.IsDir() {
+			if err := os.MkdirAll(target, 0o750); err != nil {
+				return err
+			}
+			continue
+		}
+		if err := os.MkdirAll(filepath.Dir(target), 0o750); err != nil {
+			return err
+		}
+		src, err := file.Open()
+		if err != nil {
+			return err
+		}
+		mode := info.Mode().Perm()
+		if mode == 0 {
+			mode = 0o644
+		}
+		dst, err := os.OpenFile(target, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, mode) // #nosec G304 -- target is constrained by safeZipTarget to the extraction directory.
+		if err != nil {
+			_ = src.Close()
+			return err
+		}
+		written, err := io.Copy(dst, io.LimitReader(src, maxFFmpegZipEntryBytes+1))
+		totalWritten += written
+		if err != nil {
+			_ = dst.Close()
+			_ = src.Close()
+			return err
+		}
+		if written > maxFFmpegZipEntryBytes || totalWritten > maxFFmpegZipTotalBytes {
+			_ = dst.Close()
+			_ = src.Close()
+			return fmt.Errorf("zip content too large: %s", file.Name)
+		}
+		if err := dst.Close(); err != nil {
+			_ = src.Close()
+			return err
+		}
+		if err := src.Close(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func safeZipTarget(destRoot, name string) (string, error) {
+	trimmed := strings.TrimSpace(name)
+	if strings.HasPrefix(trimmed, "/") || strings.HasPrefix(trimmed, "\\") || filepath.IsAbs(trimmed) {
+		return "", fmt.Errorf("unsafe zip path: %s", name)
+	}
+	cleanName := filepath.Clean(strings.ReplaceAll(trimmed, "\\", "/"))
+	if cleanName == "." || strings.HasPrefix(cleanName, "..") || filepath.IsAbs(cleanName) {
+		return "", fmt.Errorf("unsafe zip path: %s", name)
+	}
+	target := filepath.Join(destRoot, cleanName)
+	targetAbs, err := filepath.Abs(target)
+	if err != nil {
+		return "", err
+	}
+	rel, err := filepath.Rel(destRoot, targetAbs)
+	if err != nil || rel == "." || strings.HasPrefix(rel, "..") || filepath.IsAbs(rel) {
+		return "", fmt.Errorf("unsafe zip path: %s", name)
+	}
+	return targetAbs, nil
+}
+
+func findFFmpegPackageRoot(root string) (string, error) {
+	var ffmpegPath string
+	var ffprobePath string
+
+	err := filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			return nil
+		}
+
+		switch strings.ToLower(d.Name()) {
+		case "ffmpeg.exe":
+			ffmpegPath = path
+		case "ffprobe.exe":
+			ffprobePath = path
+		}
+		return nil
+	})
+	if err != nil {
+		return "", fmt.Errorf("扫描解压目录失败: %w", err)
+	}
+	if ffmpegPath == "" || ffprobePath == "" {
+		return "", fmt.Errorf("解压后未找到 ffmpeg/ffprobe 可执行文件")
+	}
+
+	return filepath.Dir(filepath.Dir(ffmpegPath)), nil
+}
+
+func copyDirContents(srcDir, dstDir string) error {
+	entries, err := os.ReadDir(srcDir)
+	if err != nil {
+		return err
+	}
+
+	for _, entry := range entries {
+		srcPath := filepath.Join(srcDir, entry.Name())
+		dstPath := filepath.Join(dstDir, entry.Name())
+		if err := copyTree(srcPath, dstPath); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func copyTree(srcPath, dstPath string) error {
+	info, err := os.Stat(srcPath)
+	if err != nil {
+		return err
+	}
+
+	if info.IsDir() {
+		if err := os.MkdirAll(dstPath, info.Mode()); err != nil {
+			return err
+		}
+		entries, err := os.ReadDir(srcPath)
+		if err != nil {
+			return err
+		}
+		for _, entry := range entries {
+			if err := copyTree(filepath.Join(srcPath, entry.Name()), filepath.Join(dstPath, entry.Name())); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	in, err := os.Open(srcPath) // #nosec G304 -- srcPath is produced by walking the validated extracted ffmpeg package tree.
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	if err := os.MkdirAll(filepath.Dir(dstPath), 0o750); err != nil {
+		return err
+	}
+
+	out, err := os.Create(dstPath) // #nosec G304 -- dstPath is generated under the configured ffmpeg install directory.
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	if _, err := io.Copy(out, in); err != nil {
+		return err
+	}
+
+	return out.Close()
+}