diff options
| -rw-r--r-- | pkg/sentry/fs/file.go | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go index 8c1307235..f64954457 100644 --- a/pkg/sentry/fs/file.go +++ b/pkg/sentry/fs/file.go @@ -545,12 +545,28 @@ type lockedWriter struct { // Write implements io.Writer.Write. func (w *lockedWriter) Write(buf []byte) (int, error) { - n, err := w.File.FileOperations.Write(w.Ctx, w.File, usermem.BytesIOSequence(buf), w.File.offset) - return int(n), err + return w.WriteAt(buf, w.File.offset) } // WriteAt implements io.Writer.WriteAt. func (w *lockedWriter) WriteAt(buf []byte, offset int64) (int, error) { - n, err := w.File.FileOperations.Write(w.Ctx, w.File, usermem.BytesIOSequence(buf), offset) - return int(n), err + var ( + written int + err error + ) + // The io.Writer contract requires that Write writes all available + // bytes and does not return short writes. This causes errors with + // io.Copy, since our own Write interface does not have this same + // contract. Enforce that here. + for written < len(buf) { + var n int64 + n, err = w.File.FileOperations.Write(w.Ctx, w.File, usermem.BytesIOSequence(buf[written:]), offset+int64(written)) + if n > 0 { + written += int(n) + } + if err != nil { + break + } + } + return written, err } |