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gerrit.omnirom.org / android_bionic / a05c2a2a705c8298154db6665cbbb4dbe3cdbbd5
commita05c2a2a705c8298154db6665cbbb4dbe3cdbbd5[log] [tgz]
authorElliott Hughes <enh@google.com>Wed Oct 22 12:31:02 2014 -0700
committerElliott Hughes <enh@google.com>Wed Oct 22 12:31:02 2014 -0700
tree5eb9df957ea13349671e060523fdf772c159c8cb
parent098cf45f4e853f3c85c14af0e475bfae0839f027 [diff]
Update bionic to tzdata2014i.

From the release notes:

   Changes affecting future time stamps

     Pacific/Fiji will observe DST from 2014-11-02 02:00 to
     2015-01-18 03:00.  (Thanks to Ken Rylander for the heads-up.)
     Guess that future years will use a similar pattern.

     A new Zone Pacific/Bougainville, for the part of Papua New
     Guinea that plans to switch from UTC+10 to UTC+11 on
     2014-12-28 at 02:00.  (Thanks to Kiley Walbom for the
     heads-up.)

   Changes affecting time zone abbreviations

     Since Belarus is not changing its clocks even though Moscow
     is, the time zone abbreviation in Europe/Minsk is changing
     from FET to its more-traditional value MSK on 2014-10-26 at
     01:00.  (Thanks to Alexander Bokovoy for the heads-up about
     Belarus.)

     The new abbreviation IDT stands for the pre-1976 use of UT+8
     in Indochina, to distinguish it better from ICT (UT+7).

   Changes affecting past time stamps

     Many time stamps have been corrected for Asia/Ho_Chi_Minh
     before 1976 (thanks to Trần Ngọc Quân for an indirect pointer
     to Trần Tiến Bình's authoritative book).  Asia/Ho_Chi_Minh has
     been added to zone1970.tab, to give tzselect users in Vietnam
     two choices, since north and south Vietnam disagreed after our
     1970 cutoff.

     Asia/Phnom_Penh and Asia/Vientiane have been turned into
     links, as they differed from existing zones only for older
     time stamps.  As usual, these changes affect pre-1970 time
     stamps only.  Their old contents have been moved to the
     'backzone' file.

Bug: 18085936
Change-Id: I89c065b4788b10ed7530cc4e8cfbc1b65c05c1b7
1 file changed
tree: 5eb9df957ea13349671e060523fdf772c159c8cb
  1. benchmarks/
  2. libc/
  3. libdl/
  4. libm/
  5. libstdc++/
  6. linker/
  7. tests/
  8. .gitignore
  9. ABI-bugs.txt
  10. Android.mk
  11. CleanSpec.mk
  12. README.md
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:

  1. Add entries to SYSCALLS.TXT. See SYSCALLS.TXT itself for documentation on the format.
  2. Run the gensyscalls.py script.
  3. 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.
  4. Add function declarations to the appropriate header file.
  5. 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 strace(1) can confirm that the correct system call is being made.)

Updating kernel header files

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

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

Updating tzdata

This is fully automated:

  1. Run update-tzdata.py.

Running the tests

The tests are all built from the tests/ directory.

Device tests

$ mma
$ 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/nativetest/bionic-unit-tests/bionic-unit-tests64
$ adb shell \
    /data/nativetest/bionic-unit-tests-static/bionic-unit-tests-static64

Host tests

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

$ mma
# 64-bit tests for 64-bit targets, 32-bit otherwise.
$ mm bionic-unit-tests-run-on-host
# Only exists for 64-bit targets.
$ mm bionic-unit-tests-run-on-host32

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.

$ mma
$ bionic-unit-tests-glibc32 # already in your path
$ bionic-unit-tests-glibc64

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.