In old tar formats directories are specified by appending a slash to
their names.
Directories may have sizes, but they do not have data blocks. Keep this
in mind and avoid skipping data blocks when encountering directories.
The size_t data type on 32 bit systems is smaller than int64_t. Check
the int64_t value before casting to size_t. If the value is too large
then stop operation instead of continuing operation with truncated
value.
GNU.sparse.numbytes and GNU.sparse.offset both have to be set before
gnu_add_sparse_entry can be called.
The GNU.sparse.numbytes parser checks for tar->sparse_numbytes.
This has to be tar->sparse_offset instead to work just like the
GNU.sparse.offset parser.
The variable last_digit_limit is negative since INT64_MIN itself is
negative as well. This means that the last digit after "limit" always
leads to maxval.
Turning last_digit_limit positive in itself is not sufficient because
it would lead to a signed integer overflow during shift operation.
If limit is reached and the last digit is last_digit_limit, the number
is at least maxval. The already existing if condition for even larger
(or smaller) values can be reused to prevent the last shift.
In my humble opinion it might make sense to reduce duplicated code and
keep it separated in a utility source file for shared use.
Samanta Navarro