[Slackbuilds-users] Problems with libev source

B Watson yalhcru at gmail.com
Sun Dec 24 20:46:38 UTC 2017

On 12/24/17, Daniel Prosser <dpross1100 at msn.com> wrote:

> tar: This does not look like a tar archive
> tar: Skipping to next header
> tar: Exiting with failure status due to previous errors
> So something has happened with the libev source code.

Actually, something happened to wget, last time it got updated in
Slackware. Try adding this line to /etc/wgetrc:

compression = none

...I've been trying to talk Pat into disabling wget's compression support
by default (because it's buggy, according to the wget devs themselves).

Background: Slackware 14.2's original wget didn't support compression
at all.  The latest version in patches/ is wget-1.19.2, which does support
compression, has compression enabled by default, and has a bug that causes
the problem you're having. It'll sometimes decompress a .tar.gz file
(so you end up with filename foo.tar.gz, but it's really not gzipped
any more), and in this case it gzipped the already-gzipped file:

$ wget http://dist.schmorp.de/libev/Attic/libev-4.24.tar.gz
--2017-12-24 15:32:35--  http://dist.schmorp.de/libev/Attic/libev-4.24.tar.gz
Resolving dist.schmorp.de...
Connecting to dist.schmorp.de||:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/gzip]
Saving to: ‘libev-4.24.tar.gz’

libev-4.24.tar.gz         [   <=>                    ] 512.00K
785KB/s    in 0.7s

2017-12-24 15:32:35 (785 KB/s) - ‘libev-4.24.tar.gz’ saved [524290]

$ file libev-4.24.tar.gz
libev-4.24.tar.gz: gzip compressed data, from Unix
$ md5sum libev-4.24.tar.gz
d9522a4603360ea0abde29b099470702  libev-4.24.tar.gz
$ gunzip libev-4.24.tar.gz
$ file libev-4.24.tar
libev-4.24.tar: gzip compressed data, last modified: Wed Dec 28
04:23:01 2016, max compression, from Unix
$ md5sum libev-4.24.tar
94459a5a22db041dec6f98424d6efe54  libev-4.24.tar
$ grep MD5SUM= libev.info

The file's md5sum matches after it's been gunzipped.

Turning off compression (via wgetrc or --compression none on the wget
command line) makes the problem go away, and makes wget-1.19.2 behave
the same as Slack 14.2's original wget, which had no compression support.

> I am going to email the libev author as well.

When you do, forward him a copy of this email... he might be tempted
to "fix" it by changing the script to deal with the double-gzipped
tarball, but that'll break it for anyone not using the latest wget from
patches/. Hopefully the problem will get fixed in Pat's next wget patch,
which would mean he'd have to fix his script again...

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