From: Mitch Tishmack <mitch.tishmack@gmail.com>
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Subject: [alpine-devel] Questions regarding a ghc port to alpine linux
Message-Id: <BEF5DC25-C7A1-40D2-AD39-B3279FBEF08A@gmail.com>
Date: Wed, 17 Jun 2015 23:41:33 -0500
To: alpine-devel@lists.alpinelinux.org
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Hi,

Recently a reddit haskell user cross compiled ghc in gentoo linux using =
musl libc, which convinced me to get a port of ghc functional for alpine =
linux. I did a quick query on irc and was directed to this mailing list =
to ask my questions and get a better review on the process.

My preliminary port is here under bootstrap and alpine directories.
https://github.com/mitchty/alpine-linux-ghc-bootstrap

Note, ghc itself needs to self host to build its own source. So this is =
a little more difficult to do than it normally might need be. The =
bootstrap directory contains the docker file used to generate the ghc =
cross compiler for use with the alpine docker image to generate a native =
compiler from within alpine linux.

The alpine directory right now only contains a docker file that can get =
you to generating an apk that one could use to build another apk that =
depends on ghc itself. Note, ghc requires itself to build itself from =
source. So I=E2=80=99m not entirely sure how one submits an APKBUILD in =
this circumstance, the wiki is mostly focused on non self hosting =
binaries.

This produces a functional, for some definition of the term, ghc =
compiler though I will admit I=E2=80=99m not 100% satisfied with how it =
is currently built. But it seems to function for the moment and could =
use more testing outside of my own use and abuse as well as use a bit =
better review of how I went about it to fix any glaring or obvious =
errors in approach.

Just to address a few things quick from a quick initial review from irc:
- I=E2=80=99m not a huge fan of disabling position independent code to =
build ghc, but I cannot get ghc to build reliably without it on alpine =
linux. It builds fine on non hardened gentoo linux which leads me to =
think its some side effect of PaX or grsecurity. I can build *really* =
simple programs without disabling PIE code by disabling pax via paxctl =
-cm /path/to/ghc/binary. But that apparently is the wrong tool to use so =
input here is appreciated. A note, if one does not force code compiled =
to have -nopie, the following happens: =
https://gist.github.com/mitchty/29125de21ade1a04364f=20
- I used docker for this port mostly due to wanting to try it out and it =
was nice not to have to wait 3 hours for ghc to compile its first stages =
with caching, I=E2=80=99m not wedded to the tool its more a convenience =
really since compile times for things can be rather long even on a fast =
system.
- I=E2=80=99ve talked a bit with the ghc developers regarding the -nopie =
component and either this is something new that ghc itself needs to =
detect in how linking on musl libc works, or I=E2=80=99m compiling this =
wrong in some fashion, or my understanding of how alpine is hardened is =
wrong. My knowledge of the grsecurity patches and PaX in general is low =
so I=E2=80=99m fully willing to accept that I did this preliminary port =
wrong or don=E2=80=99t understand huge portions of how alpine linux is =
built. I=E2=80=99ve mostly been a user really.

Any help or guidance on what I messed up or did wrong would be helpful. =
I=E2=80=99m just looking to get a working port of ghc onto alpine linux =
so input appreciated.

Apologies for the giant wall of text as well, thank you all for your =
time!

cheers,
mitch=


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