star-1.5a64 aborts on reading archives with _small_ garbage tails

Hi,

> This is not a bug but intended behavior on a missusage.
> A valid TAR archive is always a multiple of 512 bytes.

I plead guilty and promise to better disguise my misbehavior
in future. 


Nevertheless, please consider wether it is possible to make
sure that all uncomplained input is processed by the unpacker
before star aborts. (Of course, the unpacker should not unpack
obviously damaged data blocks.)

At restore time, any effort of the backup tool is welcome.
The mental state of the user is not the most stable one
in these moments.


My test in detail :

Although the complaint is only about my surplus bytes,
sometimes there remained some smaller files and a part of
a large file unrestored.
But not always. Often the restore is complete despite
the error message. Out of 9 tries, two delivered a damaged
restore and 7 were flawless. All 9 aborted, of course.

From the error message (of the FIFO ?) i understand that
all but my final 123 bytes were accepted on read.
Under some circumstances a tail of accepted data seems
not to be processed by the unpacker. (With star -t
these circumstances seem to be the normal case.)

A valid backup file is created :

  $ star -c /dvdbuffer >/tmp/test.star
  star: 10004 blocks + 0 bytes (total of 102440960 bytes = 100040.00k).

I spoil a copy by appending 123 bytes :

  $ cp /tmp/test.star /tmp/test_spoiled.star
  $ dd if=/dev/zero bs=1 count=123 >>/tmp/test_spoiled.star

I restore that copy

  $ star -x </tmp/test_spoiled.star
  star: WARNING: skipping leading '/' on filenames.
  star: Error reading '-' size (123) too small.
  star: 10004 blocks + 0 bytes (total of 102440960 bytes = 100040.00k).

Try #2 and #9 out of 9 did not restore properly :

  $ diff -q -r /dvdbuffer dvdbuffer
  Only in /dvdbuffer: split_dir
  Files /dvdbuffer/test/ext2_loop_fs and dvdbuffer/test/ext2_loop_fs differ
  Only in /dvdbuffer: xdir

The file ext2_loop_fs has 102400000 bytes in original
and 102018048 in the second damaged try (381952 missing).

With seven other tries the restore was ok.

  $ diff -q -r /dvdbuffer dvdbuffer
  $


Have a nice day :)

Thomas