Xavier is working on fixing random issues specific to Android since 2 years. He is almost done, the last step is just to add a build infra to get a buildbot.
https://github.com/python/cpython/pull/1629 https://bugs.python.org/issue30386 It's a set of scripts to cross compile Python from Linux to Android. >From the ones who missed it, Xavier is a core dev and will maintain this stuff ;-) Since these changes add a new directory without touching the rest of the code, I don't see a reason to not add it. Victor Le 10 déc. 2017 21:29, "Brett Cannon" <br...@python.org> a écrit : > While the note from a technical standpoint is interest, Xavier, I don't > quite see what needs to be done to support Android at this point. Are you > simply asking we add Android API 24 as an official platform? Or permission > to add your note to the Misc/ directory? Basically what are you wanting to > see happen? :) > > On Sun, 10 Dec 2017 at 06:19 Xavier de Gaye <xdeg...@gmail.com> wrote: > >> 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/ >> 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/ > victor.stinner%40gmail.com > >
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