[mkroot] Contribution

Tue Mar 6 05:50:04 PST 2018

2018-03-05 17:36 GMT+01:00 Rob Landley <rob at landley.net>:

> On 03/02/2018 04:56 AM, Ruhollah Majdoddin wrote:
> > Hello,
> > I have spent the past month over mkroot (and native build with QEMU),
>
> What do you think of it so far? (It's a newish project I haven't gotten
> too much
> feedback on yet...)
>
> I started in 2015 with Aboriginal Linux. I was searching for such a thing
to avoid Yocto for arm embedded devices.
I got a linux and compiled Lighttpd and White-Rabbit PTP natively. My chef
was satisfied.

Last month, in my new job, I tried it again. Your tutorial presentation was
very informative (I wish you could do more like that).
There was two issues.
1- The company runs a lot of software on their embedded device. So it
seemed that we needed a Linux-Distribution to manage package dependencies.
2- Mkroot still does not provide a native build system.

Therefore I tactically decided to use Debain Arm ports with QEMU.
I got a running Debian-Linux on QEMU, with that I used Gnu toolchaing to
compil the kernel from Boundary-Devices for the I.MX6 chip and run Debian
with it (I had to append the defconfig of mkroot when compiling the kernel,
to be able to run the image on the QEMU with Arm virt machine).
Finally I compiled and installed some modules from the company, I got the
system-image and installed it on the embedded device. But the chef and
other colleagues were not very excited (they feel comfortable with
Yocto/OE) and I got fired.
I can say that your presentation and mkroot, served as a guide and test
bench, to say the least.

> > now I have
> > free time for one or two months. Where can I contribute?
> > If toybox has more priority now (I see more activity there)  please tell
> me
> > where can I contribute there (I have browsed through the roadmap and
> other
> > documentation).
>
> Mkroot needs a lot of work. I haven't got the native toolchain working
> under it
> yet (partly for design reasons, there's no non-gpl make, and should ninja
> or
> cmake be in there too?), the old build control image infrastructure at
> https://landley.net/aboriginal/control-images needs to be redone in the
> new
> context, the old Linux From Scratch build image there needs to be recreated
> using current LFS... But I'm not sure any of that's a good starting place
> for a
> new developer?
>

> Reproducing the existing build with other toolchains might be nice too
> (android
> NDK, bootlin's toolchains, the crosstool images on kernel.org,
> https://ellcc.org
> and so on), but none of them provide native compilers, but they might
> start and
> it would be very nice to have an llvm build baseline.
>
This is interesting, it seems crosstool images are derived from bootlin.
Is Compert-C also an option? http://compcert.inria.fr/compcert-C.html
Although it is just a (formally verified) compiler, no assember and no
linker.

> For toybox I want to use mkroot as a way to run tests requiring root
> access and
> a known build environment, but again that's not necessarily a good starting
> point for new developers. (How you do proper "top" tests is a hard
> problem.)
> Fixing existing test failures might be, though? (Or at least diagnosing
> them, I
> haven't had time to even sort which test scripts pass and which fail, and
> which
> ones are actually providing reasonable test coverage and which aren't yet.
> It's
> on the todo list...)
>
This is also interesting. I think you mean the scripts under toybox/tests.

Something I've hit that might be worth a look is actually a qemu issue. I
> test
> new mkroot builds with something like:
>
> for i in $(./cross.sh); do (sleep 5; echo date; sleep 1; echo ifconfig;
> sleep 1;
> echo tail /dev/?da; sleep 1; echo exit; sleep 2) | ./run.sh qemu-$i |
> smokelog-$i.txt; done
>
> But when I do that, qemu often _hangs_ with current -git. Something about
> qemu's
> stdio console handling is wonky when dealing with pipes instead of pty
> instances, and I'm not sure what.
>

The Qemu problem is what I have been working on the last two days, my
laptop is not fast, it got 9 hours to build musl. Actually, I could not
reproduce the problem, it worked for me (but see below).

My system: x86_64 Sony Vaio Laptop
$ uname -a
Linux ruhollah 4.9.0-4-amd64 #1 SMP Debian 4.9.65-3+deb9u1 (2017-12-23)
x86_64 GNU/Linux

I cloned QEMU from git, compiled the Master branch with GCC (Does the
toolchain matter?)

~/qemu/build/x86_64-softmmu$ ./qemu-system-x86_64 --version
QEMU emulator version 2.11.50 (v2.11.0-1911-g136c67e078-dirty)

I built mkroot for x86_64 with GCC from debian,   and mkroot for armvl with
musl, and did similar tests with similar results.

~/mkroot/output/armv7l$ (sleep 7; echo ls; sleep 1; echo date; sleep 1;
echo tail '/dev/pts' ; sleep 1; echo ifconfig; sleep 1; echo exit; sleep 1)
|  ./qemu-armv7l.sh
.
.
.
This architecture does not have kernel memory protection.
random: fast init done
Type exit when done.
/ # ^[[50;5Rls
bin dev etc home init lib mnt proc root sbin sys tmp usr var
/ # ^[[50;5Rdate
Tue Mar  6 11:11:23 UTC 2018
/ # ^[[50;5Rtail /dev/pts
/ # ^[[50;5Rifconfig
eth0      Link encap:Ethernet  HWaddr 52:54:00:12:34:56  Driver virtio_net
          inet addr:10.0.2.15  Bcast:10.255.255.255  Mask:255.0.0.0
          inet6 addr: fec0::5054:ff:fe12:3456/64 Scope: Site
          inet6 addr: fe80::5054:ff:fe12:3456/64 Scope: Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:134 TX bytes:512

/ # ^[[50;5Rexit
reboot: Restarting system
~/mkroot/output/armv7l$ ;5R;5R;5R;5R;5R

As you see it does not hang, but there is always a "^[[50;5R" on the QEMU
prompt. Afterwards I got some ";5R" on the prompt and I have problems with
my bash settings (I‌ use Konsole): a long line does not  wrap and overruns
itself.

If I redirect the output of QEMU to a file,

~/mkroot/output/armv7l$./qemu-armv7l.sh > log.txt
^C
$vi log.txt

then I‌ see other characters at prompt. I‌f I do it with mkroot for x86_64
I get ^M (carriage return) on end of lines.
It seems to be a problem with stty (and $PS1 ?) settings. Any suggestions?

> Thanks for your interest,
>
> Rob
>
Many Thanks,
Ruhollah
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