For this to move forward more rapidly it would really help if there were a utility VM appliance available with a ready-installed support an SDK. Or at least that would lower impedance to joining the development effort. Does any such beast by chance exist?
S Steve Holden On Tue, Jan 23, 2018 at 5:17 PM, Victor Stinner <victor.stin...@gmail.com> wrote: > Ok, I created https://bugs.python.org/issue32637 > "Android: set sys.platform and os.name to android" > > Victor > > 2018-01-23 18:01 GMT+01:00 Brett Cannon <br...@python.org>: > > > > > > On Mon, 22 Jan 2018 at 09:29 Victor Stinner <victor.stin...@gmail.com> > > wrote: > >> > >> Hi, > >> > >> I'm still talking with Paul Peny (pmpp on IRC) who is trying to build > >> the master branch of Python on Android, using cross-compilation or > >> directly on an Android device. I started to took notes since Android > >> is a complex platforms and it's not easy for me to remember > >> everything. > >> > >> http://vstinner.readthedocs.io/python_android.html > >> > >> Paul would like to support Android 4.4 Kitkat (API 19) just because > >> it's possible to find cheap devices running Android, but usually only > >> with old Android versions. Technically, it doesn't see difficult to > >> support API 19+ (instead of 21+), a few tiny patches are needed. But I > >> don't want to have a "full support" of API 19+, only basic support > >> like "make sure that the compilation doesn't fail", not "all tests > >> must pass". > >> > >> It seems like sys.platform == 'android' would be more appropriate > >> since Android is not Linux: different libc, different filesystems, > >> etc. > > > > > > I've had a similar thought myself. > > > > -Brett > > > >> > >> > >> While Xavier promotes cross-compilation, Paul would like to build > >> Python directly on Android to get pip and wheels. > >> > >> Honestly, I have no strong opinion, since I don't know well Android. > >> I'm trying to help everybody working on the Android support. IMHO it's > >> fine to support multiple ways to build Python for Android. It's not > >> like there is very obvious option which has no drawback... Cross > >> compilation is complex, getting a C compiler on Android also seems to > >> be complex. From my point of view, compared to a common Fedora Linux, > >> Android doesn't seem easy to use to develop on CPython... > >> > >> Victor > >> > >> 2017-12-10 15:19 GMT+01:00 Xavier de Gaye <xdeg...@gmail.com>: > >> > The following note is a proposal to add the support of the Android > >> > platform. > >> > > >> > The note is easier to read with clickable links at > >> > https://github.com/xdegaye/cagibi/blob/master/doc/android_support.rst > >> > > >> > Motivations > >> > =========== > >> > > >> > * Android is ubiquitous. > >> > * This would be the first platform supported by Python that is > >> > cross-compiled, > >> > thanks to many contributors. > >> > * Although the Android operating system is linux, it is different from > >> > most > >> > linux platforms, for example it does not use GNU libc and runs > SELinux > >> > in > >> > enforcing mode. Therefore supporting this platform would make Python > >> > more > >> > robust and also would allow testing it on arm 64-bit processors. > >> > * Python running on Android is also a handheld calculator, a successor > >> > of > >> > the > >> > slide rule and the `HP 41`_. > >> > > >> > Current status > >> > ============== > >> > > >> > * The Python test suite succeeds when run on Android emulators using > >> > buildbot > >> > strenuous settings with the following architectures on API 24: x86, > >> > x86_64, > >> > armv7 and arm64. > >> > * The `Android build system`_ is described in another section. > >> > * The `buildmaster-config PR 26`_ proposes to update ``master.cfg`` to > >> > enable > >> > buildbots to run a given Android API and architecture on the > >> > emulators. > >> > * The Android emulator is actually ``qemu``, so the test suites for > x86 > >> > and > >> > x86_64 last about the same time as the test suite run natively when > >> > the > >> > processor of the build system is of the x86 family. The test suites > >> > for > >> > the > >> > arm architectures last much longer: about 8 hours for arm64 and 10 > >> > hours > >> > for > >> > armv7 on a four years old laptop. > >> > * The changes that have been made to achieve this status are listed in > >> > `bpo-26865`_, the Android meta-issue. > >> > * Given the cpu resources required to run the test suite on the arm > >> > emulators, > >> > it may be difficult to find a contributed buildbot worker. So it > >> > remains > >> > to > >> > find the hardware to run these buildbots. > >> > > >> > Proposal > >> > ======== > >> > > >> > Support the Android platform on API 24 [1]_ for the x86_64, armv7 and > >> > arm64 > >> > architectures built with NDK 14b. > >> > > >> > *API 24* > >> > * API 21 is the first version to provide usable support for wide > >> > characters > >> > and where SELinux is run in enforcing mode. > >> > > >> > * API 22 introduces an annoying bug on the linker that prints > >> > something > >> > like > >> > this when python is started:: > >> > > >> > ``WARNING: linker: libpython3.6m.so.1.0: unused DT entry: type > >> > 0x6ffffffe arg 0x14554``. > >> > > >> > The `termux`_ Android terminal emulator describes this problem at > >> > the > >> > end > >> > of its `termux-packages`_ gitlab page and has implemented a > >> > ``termux-elf-cleaner`` tool to strip the useless entries from the > >> > ELF > >> > header of executables. > >> > > >> > * API 24 is the first version where the `adb`_ shell is run on the > >> > emulator > >> > as a ``shell`` user instead of the ``root`` user previously, and > the > >> > first > >> > version that supports arm64. > >> > > >> > *x86_64* > >> > It seems that no handheld device exists using that architecture. It > is > >> > supported because the x86_64 Android emulator runs fast and > therefore > >> > is a > >> > good candidate as a buildbot worker. > >> > > >> > *NDK 14b* > >> > This release of the NDK is the first one to use `Unified headers`_ > >> > fixing > >> > numerous problems that had been fixed by updating the Python > configure > >> > script > >> > until now (those changes have been reverted by now). > >> > > >> > Android idiosyncrasies > >> > ====================== > >> > > >> > * The default shell is ``/system/bin/sh``. > >> > * The file system layout is not a traditional unix layout, there is no > >> > ``/tmp`` for example. Most directories have user restricted access, > >> > ``/sdcard`` is mounted as ``noexec`` for example. > >> > * The (java) applications are allocated a unix user id and a > >> > subdirectory on > >> > ``/data/data``. > >> > * SELinux is run in enforcing mode. > >> > * Shared memory and semaphores are not supported. > >> > * The default encoding is UTF-8. > >> > > >> > Android build system > >> > ==================== > >> > > >> > The Android build system is implemented at `bpo-30386`_ with `PR > 1629`_ > >> > and > >> > is documented by its `README`_. It provides the following features: > >> > > >> > * To build a distribution for a device or an emulator with a given API > >> > level > >> > and a given architecture. > >> > * To start the emulator and > >> > + install the distribution > >> > + start a remote interactive shell > >> > + or run remotely a python command > >> > + or run remotely the buildbottest > >> > * Run gdb on the python process that is running on the emulator with > >> > python > >> > pretty-printing. > >> > > >> > The build system adds the ``Android/`` directory and the > >> > ``configure-android`` > >> > script to the root of the Python source directory on the master branch > >> > without > >> > modifying any other file. The build system can be installed, upgraded > >> > (i.e. > >> > the > >> > SDK and NDK) and run remotely, through ssh for example. > >> > > >> > The following external libraries, when they are configured in the > build > >> > system, > >> > are downloaded from the internet and cross-compiled (only once, on the > >> > first > >> > run of the build system) before the cross-compilation of the extension > >> > modules: > >> > > >> > * ``ncurses`` > >> > * ``readline`` > >> > * ``sqlite`` > >> > * ``libffi`` > >> > * ``openssl``, the cross-compilation of openssl fails on x86_64 and > >> > arm64 > >> > and > >> > this step is skipped on those architectures. > >> > > >> > The following extension modules are disabled by adding them to the > >> > ``*disabled*`` section of ``Modules/Setup``: > >> > > >> > * ``_uuid``, Android has no uuid/uuid.h header. > >> > * ``grp`` some grp.h functions are not declared. > >> > * ``_crypt``, Android does not have crypt.h. > >> > * ``_ctypes`` on x86_64 where all long double tests fail > (`bpo-32202`_) > >> > and > >> > on > >> > arm64 (see `bpo-32203`_). > >> > > >> > .. [1] On Wikipedia `Android version history`_ lists the > correspondence > >> > between > >> > API level, commercial name and version for each release. It also > >> > provides > >> > information on the global Android version distribution, see the two > >> > charts > >> > on top. > >> > > >> > .. _`README`: > >> > https://github.com/xdegaye/cpython/blob/bpo-30386/Android/README.rst > >> > .. _`bpo-26865`: https://bugs.python.org/issue26865 > >> > .. _`bpo-30386`: https://bugs.python.org/issue30386 > >> > .. _`bpo-32202`: https://bugs.python.org/issue32202 > >> > .. _`bpo-32203`: https://bugs.python.org/issue32203 > >> > .. _`PR 1629`: https://github.com/python/cpython/pull/1629 > >> > .. _`buildmaster-config PR 26`: > >> > https://github.com/python/buildmaster-config/pull/26 > >> > .. _`Android version history`: > >> > https://en.wikipedia.org/wiki/Android_version_history > >> > .. _`termux`: https://termux.com/ > >> > .. _`termux-packages`: https://gitlab.com/jbwhips883/termux-packages > >> > .. _`adb`: https://developer.android.com/studio/command-line/adb.html > >> > .. _`Unified headers`: > >> > > >> > https://android.googlesource.com/platform/ndk.git/+/ndk- > r14-release/docs/UnifiedHeaders.md > >> > .. _`HP 41`: https://en.wikipedia.org/wiki/HP-41C > >> > .. vim:filetype=rst:tw=78:ts=8:sts=2:sw=2:et: > >> > _______________________________________________ > >> > Python-Dev mailing list > >> > Python-Dev@python.org > >> > https://mail.python.org/mailman/listinfo/python-dev > >> > Unsubscribe: > >> > > >> > https://mail.python.org/mailman/options/python-dev/ > victor.stinner%40gmail.com > >> _______________________________________________ > >> Python-Dev mailing list > >> Python-Dev@python.org > >> https://mail.python.org/mailman/listinfo/python-dev > >> Unsubscribe: > >> https://mail.python.org/mailman/options/python-dev/brett%40python.org > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: https://mail.python.org/mailman/options/python-dev/ > steve%40holdenweb.com >
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