Simplified approach: Store mode in pax extended header, apply best effort on Windows (ignore group/other bits, map owner read/write to deny/allow ACL entries). Detect sparse files on Windows via FSCTL_QUERY_ALLOCATED_RANGES :
| POSIX bits | Windows mapping | |------------|----------------| | 0400 (owner read) | FILE_GENERIC_READ for owner SID | | 0200 (owner write) | FILE_GENERIC_WRITE | | 0100 (owner exec) | Treat .exe/.com/.bat specially | | 0040 (group read) | Not directly mappable → set inherit flag |
bool IsSparseFile(HANDLE h) DWORD bytes; FILE_ATTRIBUTE_TAG_INFO tag = 0; DeviceIoControl(h, FSCTL_GET_NTFS_FILE_RECORD, ...); return (tag.FileAttributes & FILE_ATTRIBUTE_SPARSE_FILE) != 0;
:: List contents of a .tar.xz file tar -tf software.tar.xz