by marco.hennings@freiheit.com:

What steps will reproduce the problem?

1. write a new tarfile
2. add a header for a link or symlink with more than 100 characters

What is the expected output?

A pax header should be written and no error should occur

What do you see instead?

The pax header is written but it still causes an error that the header was too long.


The reason lies within the following code fragment:

    if len(hdr.Name) > fileNameSize || len(hdr.Linkname) > fileNameSize {
        var err error
        prefix, suffix, err = tw.splitUSTARLongName(hdr.Name)
        // Either we were unable to pack the long name into ustar format
        // or the link name is too long; use PAX headers.
        if err == errNameTooLong || len(hdr.Linkname) > fileNameSize {
            if err := tw.writePAXHeader(hdr); err != nil {
                return err
            } 
        } else if err != nil {
            return err
        }
    }
     [... ]
    tw.cStringw(s.next(100), hdr.Linkname, "linkname")  // linkname (157:257)

In the last line you see that the linkname is added even if it was written in the pax
header.


To solve this I have implemented missing parts of the pax header support. Attached you
find a patch. I will provide a mercurial contribution soon.

Attachments:

1. fix-tar-pax-support.patch (13859 bytes)