[Haskell-cafe] Haskell on OpenWRT

Sun Apr 10 19:57:23 UTC 2016

Thanks!  I'll take a look at building a cross-compiler, since it worked 
out for you.  I'd been a little afraid to try.  (I previously had a bad 
experience building ghc as a cross-compiler, but that was with Android 
as the target and Mac OS X as the host.  The issues I encountered were 
mostly when it tried to link ELF binaries with the Mach-O linker, or 
vice versa.  But with both host and target being Linux, the linker 
issues can probably be swept under the rug.)

The C cross compiler shouldn't be a problem, since OpenWRT's "buildroot" 
builds a cross-compiler automatically.  (Though if for any reason that 
turns out to be a problem, thanks for the tip about crosstool-ng.)  
Ideally, I'd love to integrate ghc into OpenWRT's buildroot so that 
packages written in Haskell could be built as easily and in the same way 
as packages written in C.  But I still have a lot to learn before I 
attempt that.

My boot device is an SD card, so space for static binaries shouldn't be 
a problem.  I already have several gigabytes, which should be more than 
enough, and if for some reason I needed more space, I could swap in a 
larger SD card, or add more space via USB or mSATA.

I was aware of Marios Titas's "GHC + musl = easier static linking", but 
wasn't really thrilled at the idea of needing an install of Gentoo-musl 
to host it.  (But I can certainly try that if I have to.)  Or I could 
just use my OpenWRT box to host the GHC-musl, but I'm running into 
issues with getting gcc to run on the target, which I'm currently 
following up with the OpenWRT community.

Thanks for the ideas!  I'm sure that one way or another I'll be able to 
get it working.

--Patrick

On 4/10/16 8:40 AM, Tomas Carnecky wrote:
> I was able to compile Haskell for a mips-linux-musl target 
> (https://onion.io/omega). Most problems were due to the different 
> architecture (MIPS) than musl. Once you have a C cross-compiler (I 
> used http://crosstool-ng.org/ to built the cross-compiler toolchain), 
> compiling GHC as a cross compiler for that target and then a Haskell 
> application shouldn't be a problem.
>
> If you have enough disk space on the target, I would suggest that you 
> compile your Haskell application into a static binary.
>
> On Sat, Apr 9, 2016 at 10:47 AM Lana Black <lanablack at amok.cc> wrote:
>
>     You will probably have better luck using ghc with musl‎.
>
>     Check out this thread:
>     ‎https://mail.haskell.org/pipermail/haskell-cafe/2015-May/119843.html
>
>       Original Message
>     From: Patrick Pelletier
>     Sent: Saturday, April 9, 2016 7:54 AM
>     To: haskell-cafe
>     Subject: [Haskell-cafe] Haskell on OpenWRT
>
>     Has anyone had any success running Haskell programs on OpenWRT?
>
>     Specifically, I'm running OpenWRT on x86_64, so processor architecture
>     shouldn't be an issue. However, by default OpenWRT uses musl as its C
>     library, so binaries from a "normal" Linux system wouldn't be
>     compatible
>     with OpenWRT.
>
>     I attempted to get around this problem by building an OpenWRT
>     image with
>     glibc as the C library. In theory, that ought to solve the problem. In
>     practice, my program (a simple hello-world type program, which
>     runs fine
>     on Ubuntu) hung, printing nothing, using nearly all of one core,
>     and was
>     unkillable by any signal other than SIGKILL. If left alone to run, it
>     eventually used all available memory and then died.
>
>     I took a look at ldd, to see if there were any clues there. On my
>     Ubuntu 12.04 machine, where I compiled the program (using ghc
>     7.4.1), I get:
>
>     ppelletier at patrick64:~/programming/haskell$ ldd contact
>     linux-vdso.so.1 => (0x00007fff36f50000)
>     libgmp.so.10 => /usr/lib/x86_64-linux-gnu/libgmp.so.10
>     (0x00007f8d49cf8000)
>     libffi.so.6 => /usr/lib/x86_64-linux-gnu/libffi.so.6
>     (0x00007f8d49af0000)
>     libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f8d497f3000)
>     librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f8d495eb000)
>     libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f8d493e7000)
>     libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f8d49028000)
>     libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
>     (0x00007f8d48e0b000)
>     /lib64/ld-linux-x86-64.so.2 (0x00007f8d49f8d000)
>
>     On my OpenWRT (trunk) box, I get:
>
>     root at OpenWrt:~# ldd /tmp/contact
>     linux-vdso.so.1 (0x00007ffd2afcc000)
>     libgmp.so.10 => /usr/lib/libgmp.so.10 (0x00007f27a057a000)
>     libffi.so.6 => /usr/lib/libffi.so.6 (0x00007f27a0373000)
>     libm.so.6 => /lib/libm.so.6 (0x00007f27a0080000)
>     librt.so.1 => /lib/librt.so.1 (0x00007f279fe79000)
>     libdl.so.2 => /lib/libdl.so.2 (0x00007f279fc76000)
>     libc.so.6 => /lib/libc.so.6 (0x00007f279f906000)
>     libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x00007f279f6f4000)
>     libpthread.so.0 => /lib/libpthread.so.0 (0x00007f279f4d9000)
>     /lib64/ld-linux-x86-64.so.2 (0x00007f27a07dc000)
>
>     This is almost the same, except it has "libgcc_s.so.1", while on the
>     Ubuntu box it does not.
>
>     I'd welcome any ideas on how to solve (or at least diagnose) this
>     problem. I'd also be interested in any thoughts on the broader
>     question
>     of running Haskell programs on OpenWRT.
>
>     Thanks,
>
>     --Patrick
>
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