Files
trivy/pkg/module/memfs.go
2024-05-27 02:53:19 +00:00

72 lines
2.2 KiB
Go

package module
import (
"io"
"io/fs"
"path/filepath"
"time"
"golang.org/x/xerrors"
"github.com/aquasecurity/trivy/pkg/mapfs"
xio "github.com/aquasecurity/trivy/pkg/x/io"
)
// memFS is a wrapper of mapfs.FS and can change its underlying file system
// at runtime. This implements fs.FS.
type memFS struct {
current *mapfs.FS
}
// Open implements fs.FS.
func (m *memFS) Open(name string) (fs.File, error) {
if m.current != nil {
return m.current.Open(name)
}
// memFS is always a directory.
if name == "." {
return &emptyDir{}, nil
}
return nil, fs.ErrNotExist
}
// initialize changes the underlying memory file system with the given file path and contents.
//
// Note: it is always to safe swap the underlying FS with this API since this is called only at the beginning of
// Analyze interface call, which is not concurrently called per module instance.
func (m *memFS) initialize(filePath string, content xio.ReadSeekerAt) error {
mfs := mapfs.New()
if err := mfs.MkdirAll(filepath.Dir(filePath), fs.ModePerm); err != nil {
return xerrors.Errorf("mapfs mkdir error: %w", err)
}
b, err := io.ReadAll(content)
if err != nil {
return xerrors.Errorf("read error: %w", err)
}
err = mfs.WriteVirtualFile(filePath, b, fs.ModePerm)
if err != nil {
return xerrors.Errorf("mapfs write error: %w", err)
}
m.current = mfs
return nil
}
type emptyDir struct{}
func (emptyDir) Close() (err error) { return }
func (emptyDir) Stat() (fs.FileInfo, error) { return fakeRootDirInfo{}, nil }
func (emptyDir) Read([]byte) (int, error) {
return 0, &fs.PathError{Op: "read", Path: "/", Err: fs.ErrInvalid}
}
type fakeRootDirInfo struct{}
func (fakeRootDirInfo) Name() string { return "/" }
func (fakeRootDirInfo) Size() int64 { return 0 }
func (fakeRootDirInfo) Mode() fs.FileMode { return fs.ModeDir | 0o500 }
func (fakeRootDirInfo) ModTime() time.Time { return time.Unix(0, 0) }
func (fakeRootDirInfo) IsDir() bool { return true }
func (fakeRootDirInfo) Sys() any { return nil }
func (emptyDir) ReadDir(int) (dirents []fs.DirEntry, err error) { return }