Error: Invalid tar header. Maybe the tar is corrupted or it needs to be gunzipped?

[palavrov]

tar-stream/extract.js

Lines 180 to 181 in b737a8d

	self.emit('entry', header, self._stream, onunlock)
	self._parse(header.size, onstreamend)

If header.size is modified for some reason in entry event handler causes this error. For now quick fix is just to avoid modifying the header.size in the event handler but at least it needs to be documented or even better to make and use a copy of the size in local variable.

[PaulMcGuinness]

I'm getting this error on certain tar file that unpacks perfectly fine using other tools, any thoughts? (I've zipped it up to attach it here) - The tar's come from a vxWorks platform if that helps?

backup_dbsave_cfg1sw4_11.0.2.82_20150609084847.tar.zip

[palavrov]

@PaulMcGuinness, the issue I got was caused by me modifying tar-stream header.size variable. If your code is modifying this variable too could be a good reason for this error message.

[PaulMcGuinness]

No, not doing any modifications. Using the simple example code. It's definitely tar version related (as newer versions of the same platform's backup work fine)

[palavrov]

So ... I debugged a bit and got the problem - your tar file fails the proper header checks ( look here if you are curious

tar-stream/headers.js

Line 264 in e08fcd8

if (USTAR_MAGIC.compare(buf, MAGIC_OFFSET, MAGIC_OFFSET + 6) === 0) {

).

Solution is to:

1. Conform with the expected tar file format.
2. Pass to extract({allowUnknownFormat:true})
3. Do a PR here with a fix how to detect the header

I would suggest to go for 1

[PaulMcGuinness]

Many thanks for the solutions - I can't change the tar format, and (3) is outside my abilities, so I'll try (2) tomorrow :-)

[PaulMcGuinness]

Option (2) worked perfectly - Many thanks! :-)

[mafintosh]

If you wanna add a note about that to the readme send a PR 😊