commit	e131f6cf33c4d99522e762d6365a3f2b75037875	[log] [tgz]
author	Joachim Sauer <jsauer@google.com>	Fri Sep 30 16:36:51 2016 +0100
committer	Joachim Sauer <jsauer@google.com>	Fri Sep 30 16:49:38 2016 +0100
tree	4055c506a6554aff30d253b76a9cebbf68872bb8
parent	b81ade620359582c509229a56f17cc1feeb0dd9e [diff]

Update timezone data to 2016g.

The 2016g release of the tz code and data is available. It reflects the
following changes, which were either circulated on the tz mailing list
or are relatively minor technical or administrative changes:

  Changes to future time stamps

    Turkey switched from EET/EEST (+02/+03) to permanent +03,
    effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
    than an invented abbreviation for the new time.

    New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
    (Thanks to Tim Parenti.)

  Changes to past time stamps

    For America/Los_Angeles, spring-forward transition times have been
    corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
    1950-1966.

    For zones using Soviet time on 1919-07-01, transitions to UT-based
    time were at 00:00 UT, not at 02:00 local time.  The affected
    zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
    Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)

  Changes to past and future time zone abbreviations

    The Factory zone now uses the time zone abbreviation -00 instead
    of a long English-language string, as -00 is now the normal way to
    represent an undefined time zone.

    Several zones in Antarctica and the former Soviet Union, along
    with zones intended for ships at sea that cannot use POSIX TZ
    strings, now use numeric time zone abbreviations instead of
    invented or obsolete alphanumeric abbreviations.  The affected
    zones are Antarctica/Casey, Antarctica/Davis,
    Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
    Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
    Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
    Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
    Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
    Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
    Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
    Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
    Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
    Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
    Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
    Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
    Europe/Minsk, Europe/Samara, Europe/Volgograd, and
    Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
    was replaced by +05, whereas MSK and MSD were kept as they are not
    our invention and are widely used.

  Changes to zone names

    Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
    (Thanks to David Massoud.)

Test: Ran CTS modules CtsLibcoreTestCases and CtsBionicTestCases.
Bug: 31848040
Change-Id: I1e652ce2e428d44ba143e4ca9630fd2dc46087e4

libc/zoneinfo/tzdata[diff]

1 file changed

tree: 4055c506a6554aff30d253b76a9cebbf68872bb8

README.md

Working on bionic

What are the big pieces of bionic?

libc/ --- libc.so, libc.a

The C library. Stuff like fopen(3) and kill(2).

libm/ --- libm.so, libm.a

The math library. Traditionally Unix systems kept stuff like sin(3) and cos(3) in a separate library to save space in the days before shared libraries.

libdl/ --- libdl.so

The dynamic linker interface library. This is actually just a bunch of stubs that the dynamic linker replaces with pointers to its own implementation at runtime. This is where stuff like dlopen(3) lives.

libstdc++/ --- libstdc++.so

The C++ ABI support functions. The C++ compiler doesn't know how to implement thread-safe static initialization and the like, so it just calls functions that are supplied by the system. Stuff like __cxa_guard_acquire and __cxa_pure_virtual live here.

linker/ --- /system/bin/linker and /system/bin/linker64

The dynamic linker. When you run a dynamically-linked executable, its ELF file has a DT_INTERP entry that says "use the following program to start me". On Android, that's either linker or linker64 (depending on whether it's a 32-bit or 64-bit executable). It's responsible for loading the ELF executable into memory and resolving references to symbols (so that when your code tries to jump to fopen(3), say, it lands in the right place).

tests/ --- unit tests

The tests/ directory contains unit tests. Roughly arranged as one file per publicly-exported header file.

benchmarks/ --- benchmarks

The benchmarks/ directory contains benchmarks.

What's in libc/?

Adding system calls

Adding a system call usually involves:

Add entries to SYSCALLS.TXT. See SYSCALLS.TXT itself for documentation on the format.
Run the gensyscalls.py script.
Add constants (and perhaps types) to the appropriate header file. Note that you should check to see whether the constants are already in kernel uapi header files, in which case you just need to make sure that the appropriate POSIX header file in libc/include/ includes the relevant file or files.
Add function declarations to the appropriate header file.
Add the function name to the correct section in libc/libc.map.txt and run ./libc/tools/genversion-scripts.py.
Add at least basic tests. Even a test that deliberately supplies an invalid argument helps check that we're generating the right symbol and have the right declaration in the header file, and that you correctly updated the maps in step 5. (You can use strace(1) to confirm that the correct system call is being made.)

Updating kernel header files

As mentioned above, this is currently a two-step process:

Use generate_uapi_headers.sh to go from a Linux source tree to appropriate contents for external/kernel-headers/.
Run update_all.py to scrub those headers and import them into bionic.

Updating tzdata

This is fully automated (and these days handled by the libcore team, because they own icu, and that needs to be updated in sync with bionic):

Run update-tzdata.py in external/icu/tools/.

Verifying changes

If you make a change that is likely to have a wide effect on the tree (such as a libc header change), you should run make checkbuild. A regular make will not build the entire tree; just the minimum number of projects that are required for the device. Tests, additional developer tools, and various other modules will not be built. Note that make checkbuild will not be complete either, as make tests covers a few additional modules, but generally speaking make checkbuild is enough.

Running the tests

The tests are all built from the tests/ directory.

Device tests

$ mma
$ adb remount
$ adb sync
$ adb shell /data/nativetest/bionic-unit-tests/bionic-unit-tests32
$ adb shell \
    /data/nativetest/bionic-unit-tests-static/bionic-unit-tests-static32
# Only for 64-bit targets
$ adb shell /data/nativetest64/bionic-unit-tests/bionic-unit-tests64
$ adb shell \
    /data/nativetest64/bionic-unit-tests-static/bionic-unit-tests-static64

Note that we use our own custom gtest runner that offers a superset of the options documented at https://github.com/google/googletest/blob/master/googletest/docs/AdvancedGuide.md#running-test-programs-advanced-options, in particular for test isolation and parallelism (both on by default).

Host tests

The host tests require that you have lunched either an x86 or x86_64 target.

$ ./tests/run-on-host.sh 32
$ ./tests/run-on-host.sh 64   # For x86_64-bit *targets* only.

You can supply gtest flags as extra arguments to this script.

Against glibc

As a way to check that our tests do in fact test the correct behavior (and not just the behavior we think is correct), it is possible to run the tests against the host's glibc.

$ ./tests/run-on-host.sh glibc

Gathering test coverage

For either host or target coverage, you must first:

$ export NATIVE_COVERAGE=true
- Note that the build system is ignorant to this flag being toggled, i.e. if you change this flag, you will have to manually rebuild bionic.
Set bionic_coverage=true in libc/Android.mk and libm/Android.mk.

Coverage from device tests

$ mma
$ adb sync
$ adb shell \
    GCOV_PREFIX=/data/local/tmp/gcov \
    GCOV_PREFIX_STRIP=`echo $ANDROID_BUILD_TOP | grep -o / | wc -l` \
    /data/nativetest/bionic-unit-tests/bionic-unit-tests32
$ acov

acov will pull all coverage information from the device, push it to the right directories, run lcov, and open the coverage report in your browser.

Coverage from host tests

First, build and run the host tests as usual (see above).

$ croot
$ lcov -c -d $ANDROID_PRODUCT_OUT -o coverage.info
$ genhtml -o covreport coverage.info # or lcov --list coverage.info

The coverage report is now available at covreport/index.html.

Attaching GDB to the tests

Bionic's test runner will run each test in its own process by default to prevent tests failures from impacting other tests. This also has the added benefit of running them in parallel, so they are much faster.

However, this also makes it difficult to run the tests under GDB. To prevent each test from being forked, run the tests with the flag --no-isolate.

32-bit ABI bugs

This probably belongs in the NDK documentation rather than here, but these are the known ABI bugs in the 32-bit ABI:

time_t is 32-bit. http://b/5819737. In the 64-bit ABI, time_t is 64-bit.
off_t is 32-bit. There is off64_t, and in newer releases there is almost-complete support for _FILE_OFFSET_BITS. Unfortunately our stdio implementation uses 32-bit offsets and -- worse -- function pointers to functions that use 32-bit offsets, so there's no good way to implement the last few pieces http://b/24807045. In the 64-bit ABI, off_t is off64_t.
sigset_t is too small on ARM and x86 (but correct on MIPS), so support for real-time signals is broken. http://b/5828899 In the 64-bit ABI, sigset_t is the correct size for every architecture.