[SOLVED] .deb Built with dpkg .vs .deb Build with ar

[Deluge]

I was experimenting a little with .deb packages and wanted to see if I could manually build a package with tar, gzip, and ar. Well.... it didn't install. So I created a package with dpkg to compare it with.

Command using dpkg:

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$ fakeroot dpkg -b blarg blarg_0.1_all.deb

Commands using tar, gzip, and ar:

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$ tar -cf data.tar ./usr
$ gzip data.tar
$ tar -cf control.tar ./control
$ gzip control.tar
$ ar rcs blarg_0.1_all.deb data.tar.gz control.tar.gz debian-binary

So now I have two .deb packages called blarg_0.1_all.deb. They both have identical content, but the one built with ar does not install. I read that a .deb is an ar package. But dpkg must do something more. Does anyone want to let me in on the secret?

Here are the contents of the two packages:

dpkg:

• control.tar.gz
  • ./control
• data.tar.gz
  • ./usr/bin/blarg
• debian-binary

ar:

• control.tar.gz
  • ./control
• data.tar.gz
  • ./usr/bin/blarg
• debian-binary

Here is the error that comes up when I try to install the ar package:

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dpkg-deb: file `blarg_0.1_all.deb' is not a debian binary archive (try dpkg-split?)
dpkg: error processing blarg_0.1_all.deb (--install):
 subprocess dpkg-deb --control returned error exit status 2
Errors were encountered while processing:
 blarg_0.1_all.deb

Edit: I just found this article, it looks like it is not possible to create a working deb this way: http://wilmer.gaast.net/blog/archives/3 ... t-....html

[mzilikazi]

Edit: I just found this article, it looks like it is not possible to create a working deb this way

Or is it?

[bugsbunny]

I suspect the problem traces it's roots into the dawn of (Debian) time and the creation of the deb format. The problem is that the deb format uses the bsd version of ar, which is incompatible with gnu ar for some reason. I do wonder why the bsd version of ar isn't included in bsdutils though.

[Deluge]

Or is it?

I read through that article, but it still didn't work. I didn't realize that, as bugsbunny was saying, there are two different versions of ar. I am going to seek out the BSD version. Thanks bugs.

[mzilikazi]

I didn't realize that, as bugsbunny was saying, there are two different versions of ar. I am going to seek out the BSD version. Thanks bugs.

That is an interesting point. To what end may I ask are you building .debs this way? Just a learning experience?

[Deluge]

It's mostly just learning experience, but I would also like to experiment building debs on a win32 platform.

BTW, does anyone know where I can find the BSD binutils/ar packages?

[AdrianTM]

Interesting idea, I wonder if it's not a permission issue too.

[Deluge]

I found what I was doing wrong. It turns out that you don't need a BSD version of ar.

Just use these commands to create a valid deb:

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tar -czf control.tar.gz ./control
tar -czf data.tar.gz ./build
ar rcv blarg_0.1_all.deb debian-binary control.tar.gz data.tar.gz

(which is almost identical to what I was doing)

The only way I can reproduce the error is if I change the order of files in the ar command:

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ar rcv blarg_0.1_all.deb data.tar.gz control.tar.gz debian-binary

So it appears that "debian-binary" has to be listed before the gzipped files or else the resulting deb will not be valid.

You can do it the way I originally posted as well, just put debian-binary first in the ar line:

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tar -cf data.tar ./usr
gzip data.tar
tar -cf control.tar ./control
gzip control.tar
ar rcs blarg_0.1_all.deb debian-binary data.tar.gz control.tar.gz

[bugsbunny]

See this link, and then see the related bug report (linked to from the post)
Re: [CMake] Producing deb package with 'ar'

Bottom line - the differences are subtle. The debs may sometimes work, but sometimes they may not.

[Deluge]

Thanks for letting me know about that, I would have never known anything was wrong with the debs. If I get the bsd variant I should be able to build packages without any problems, correct?

I found a wikipedia article that talks about the differences as well: http://en.wikipedia.org/wiki/Ar_%28Unix%29#BSD_variant

Edit: I still cant find the bsd variant .

[bugsbunny]

I played with all this a long time back (which is why I knew about the difference). I also looked for the bsd variant, but couldn't find anything practical.

[Deluge]

I think I found the source here: http://people.freebsd.org/~kaiw/distfiles/. But I don't know how to compile it .

Edit: Actually, I think that is the source for bsdar. I don't know if it is the same thing as ar.

[Deluge]

I think I did it (who knows if it will work right after I messed with the source). I now have what appears to be a bsd variant ar executable:

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$ ./ar --version
BSD ar 1.0.2 - libarchive 2.6.2

[Deluge]

It works, but I won't be able to do any experimenting on Win32. I am unable to compile it for that platform .

[debpat]

I think I did it (who knows if it will work right after I messed with the source). I now have what appears to be a bsd variant ar executable:

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$ ./ar --version
BSD ar 1.0.2 - libarchive 2.6.2

I'm trying to convert some debs from gzip to lzma... is your BSD AR "debianization" source code available?
thanks

[stevepusser]

I think I did it (who knows if it will work right after I messed with the source). I now have what appears to be a bsd variant ar executable:

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$ ./ar --version
BSD ar 1.0.2 - libarchive 2.6.2

I'm trying to convert some debs from gzip to lzma... is your BSD AR "debianization" source code available?
thanks

Interesting...I know how to compile and create lzma debs the standard way, by adding the option to do so to dh_builddeb in the debian/rules file, but not how to do it manually.

[debpat]

never mind,
the BSD ar is not the way to go...

instead I took a look at "dpkg-deb"; everything is there... I used ubuntu sources..
/dpkg-1.14.16.6ubuntu4.1/dpkg-deb/extract.c & build.c show how the debian files are created

dpkg-deb allows to unassemble a deb/udeb file (a 2 step process) and reassemble it choosing the compression I need...

tested; everything works great

thanks
Patrick

[Deluge]

I did a better job of porting the source over to Linux this time. It was mostly just adding some defines:

Linux x86 binaries: https://sourceforge.net/projects/deluge ... ties/bsdar
Source code: https://sourceforge.net/projects/deluge ... inux/bsdar

If someone compiles it for 64 bit please send me a copy of the binary.