• The KBOX3 project
KBOX3 development diary
For comments and general information on the previous version of
KBOX, KBOX2, please see here
Despite my previous pessimism, KBOX3 does work on (at least some)
64-bit Android devices. I guess that I've become so used to Google
repeatedly changing Android in ways that break KBOX, I was too quick to
jump to the assumption that they had done so again. However, it
turns out this time to be a "d'oh!" moment on my part.
In some shell scripts I had specified the interpreter like this:
when the usual formula is:
This was a hangover from the very early days of KBOX, when the reference
to the Android shell in
/system/bin was necessary. It has
not been necessary for several years, but I hadn't quite gotten out of the
habit of using it. Refering to the Android shell wasn't a problem on
32-bit devices, but on a 64-bit Android the stock shell is a 64-bit
binary, and everything in KBOX is 32-bit. So when we try to load the
libfakechroot.so library into the process, it fails because
the bit-widths don't match.
This problem only affects packages that use shell scripts, and I've been
through the whole distribution and (I hope) fixed all such scripts. I have
uploaded corrected versions of the broken packages to my downloads page.
However, it's possible that I have missed some scripts, so do please let
me know if you get errors about not being able to load a 32-bit library
into a 64-bit process, and I'll try to fix them.
As a side note, KBOX3 only works on 64-bit Android devices because
the platform provides some measure of 32-bit backward compatibility. Although
it would be possible, in principle, to rebuild the whole of
KBOX3 to be 64-bit-clean, I can see no benefit at all in doing so
KBOX3 does not currently work on any 64-bit Android device.
Yep, Google has found
another way to stop KBOX working, although I doubt it was intentional.
On a 64-bit device, even if the KBOX shell starts up, attempting to run
any program will result an error message of this form:
At present, this means that KBOX3 won't work on the HTC One M8S and M8,
the Nexus 9, and the Samsung Galaxy S6, and a few other devices.
However, it seems
likely that more vendors will move to a 64-bit version of Android 5
in future, and this could well spell the end for KBOX. On a side note,
I suspect that the move to 64-bit is to take advantage of the newer
ARMv8 architecture, not because any Android app is likely to need a
64-bit address space.
The odd thing is that
CANNOT LINK EXECUTABLE DEPENDENCIES:
"/data/data/jackpal.androidterm/kbox3/lib/libfakechroot.so" is 32-bit instead of 64-bit
libfakechroot.so is not loaded, the whole operating
basis of KBOX is undermined. This library is used to fake the Linux-like
filesystem on top of the Android filesystem that all KBOX executables
libfakechroot.so is indeed a
32-bit executable, as is everything else in KBOX3. I can't for
the life of me understand why Android thinks this library ought
to be 64-bit, when
it is being preloaded into a 32-bit application. Of course, there are
a great many things about Android that I don't understand. In principle,
I could build a 64-bit version of
I can't think of any reason for it to work with 32-bit code.
The truly bizarre thing, however, is that the KBOX shell starts up at
all, given this problem. It seems that it does start, and it finds files
where they should be, which means that
doing what it should. It's only when the shell tries to launch further
executables that Android starts complaining about the library bit-width.
I fear that the only solution is to rebuild the whole of KBOX as
64-bit. Since I've only recently recovered from the pain of rebuilding
it as position-independent to suit Android 5, that isn't a job I
intend to undertake for a long time, if ever.
At long last,
gcc is now available for KBOX3. The
package can be obtained from the Downloads page. This is an
early release and there could well still be problems. For
more information, see here.
A lot of folks who have tried KBOX3 have found that the shell won't even
start up, because of a reported missing
Support for the
dlopen() function (for dynamically loading
libraries) has been a serious nuisance throughout the whole of the KBOX
project. Support for this function seems to vary from device to device
in an unpredictable way. Unfortunately, I've never been able to reproduce
I've recently had a contribution of a modified version of
libfakechroot.so, which is known to make KBOX3 work on at least
one Android 5 device. I'm recommending that anybody who sees errors about
dlopen download and install fixed version 1 of
libfakechroot.so. Just copy this over the existing
libfakechroot.so version in the
I've called this 'fixed version 1' because I can't be sure that other modified
versions won't be needed for other systems, unfortunately.
On a more positive note, I've had a new build of GCC from Cyd Haselton which
should restore C compiler support to KBOX3, much missed until now. I was
unable to build GCC on my desktop workstation in a way that worked on
Android 5 (because of the position-independent binary requirements, among
other things). The trick — which I confess I would not have thought
of myself — was to build GCC on the device under Android 4.4,
which did not have these restrictions. I'm still working on getting this
new build packaged up for distribution, but it's looking promising so far.
I've released a first attempt at some utilities to support building
Java applications directly on the Android device. For more
information, see here.
I've built gnuchess for KBOX3, which was straightforward. I was hoping
to build the ncurses interface 'cboard' but, alas, the source is full of
wide-character functions that have no implementation in Android Bionic.
These problems might be surmountable, if there's enough demand for this
to make it worth the effort.
Python 3 is now working on KBOX3. The problem, as so often that case with
Android 5, was figuring out how to specify all the necessary compiler/linker
switches in the rather complicated build system. Python modules are built
as shared objects — it should be possible, in principle to link them
statically to the main executable, but that didn't work for me at all — and the linker needs these binaries' dependencies
explicitly, even though they are specified on the
main executable. Since the Python build system does not do this without a good
deal of fiddling, I assume that's not something that is necessary with
I managed to build the latest (at this time) version of Perl — 5.20.2.
I made use of Alex Suylok's cross-compiler patch for Perl, because
building Perl is a real bear otherwise. I can't begin to understand why
building Perl needs to be quite the nightmare that it is, but there are
many things I don't understand, so nobody should be surprised by that.
For KBOX2 I unpacked the Perl binaries from Google's Android Scripting
tools, but these don't work on Android 5, so I had to build from scratch.
I've only run simple tests, and I have no idea how this build of Perl
will perform with anything that involves dynamic loading (but I can guess
it won't be an unmitigated success.) Still, for routine stuff it seems
I've managed to port Git (code repository management utility) to KBOX3.
The problem, as it so often is, was figuring out to get the appropriate
compiler switches and library references into Git's complicated
configuration system. I've only tested with basic pull and push operations,
which seem to work fine, including with
I have not included any CA certificates in the package, so operations
that work over SSL need to have
in the environment. Since a growing number of utilities need CA
certificates, perhaps a better approach would be provide them in a
separate package, and build these utilities so they look in the appropriate
Work on support for Android 5 has started at last. Because the differences
are so substantial, I've decided to start a whole new project — KBOX3 — and retire KBOX2. Supporting one Linux distribution single-handed in
my spare time is difficult enough; two would be a nightmare. I
don't know to what extent KBOX3 will work with Android versions
prior to 5, but I'm not aiming to support them, nor old hardware. KBOX2
will remain available, in its current form, for the forseeable future.
Porting Linux applications to run under Android 5 is no easier
than porting them to Android 3-4 was. KBOX3 takes the same basic
approach, of providing a virtual filesystem that looks like a
normal root filesystem. However, there are now even more restrictions
on access to system files and devices, along with the absurd and
demoralizing requirement to build everything in position-independent code.
At the time of writing, even Google's own builds of scripting languages
like Perl and Lua remain disfunctional on Android 5, and there's no
indication that this will change any time soon.
The situation has been worsened by the fact that later versions of
the Google Android NDK — which are required for Android 5 — have even
more bits missing than previous versions. In some cases, where the problems
are justing missing header files, I've been able to fix the problems just
by copying in the missing bits from a previous release. However, a number
of standard C library calls that were just useless stubs in the old versions
of Android Bionic are now missing altogether. In a sense that's a good thing — it's surely better that something fail to build, than that it builds and
then fails in use. But despite the missing code, most of the packages I
built for KBOX2 did seem to work, and considerable changes are sometimes
required to replace the functionality that has been removed, even with
A particularly irritating finding with Android 5 is that there are some
functions defined in the NDK that don't exist in the actual on-device
Bionic implementation. Some packages that rely on auto-configuration to
probe the compiler to find what it offers can fail, because
the generated code contains referencs to missing functions.
All in all, a horrible job made more horrible. Still, the packages
that I started KBOX to use — Busybox, Dropbear, and Vim — are
all working, as are about 80% of the other stuff from KBOX2. The
big, complex packages like Perl and gcc are currently not available
and, as they were contributed by other people — all of whom are
volunteers as I am — I don't know when that situation will change.