The use of ReadAtOffset is meant to allow concurrent access
to the zip archive once it has been loaded. There were places
where this was the case, and some places that did a seek + read
combination, which could lead to data races.
NOTE: On Windows, we are not using pread as the implementation of
ReadAtOffset, therefore the guarantees on Windows are weaker.
On Linux, pread allows the file descriptor to be read at a specific
offset without changing the read pointer. This allows inherited fd's
and duped fds to be read concurrently.
On Windows, we use the ReadFile API, which allows for an atomic seek +
read operation, but modifies the read pointer. This means that any mix
use of ReadAtOffset and Read will have races. Just using ReadAtOffset is
safe.
For the Windows case, this is fine as the libziparchive code now only
uses ReadAtOffset.
Bug: 62184114
Bug: 62101783
Test: make ziparchive-tests (existing tests pass)
Change-Id: Ia7f9a30af2216682cdd9d578d26e84bc46773bb9
Tests will often want to get the executable directory in order to
find test data.
Test: out/host/linux-x86/nativetest64/libbase_tests/libbase_tests
Change-Id: Ica9d211bcd039fcf83a22fd494816abd01b97aa3
adb already provides an implementation of dirname and basename that
take and produce std::strings, move it into libbase so it can be
used in the implementation of GetExecutableDirectory.
Test: out/host/linux-x86/nativetest64/adb_test/adb_test
Test: out/host/linux-x86/nativetest64/libbase_test/libbase_test
Test: adb shell /data/nativetest64/libbase_test/libbase_test64
Change-Id: Ideb1627607b14562121316d4ed27fa6fb0930684
We'd long had two copies of this stuff, so rather than rewrite both
Linux versions to use android::base::Readlink, let's kill the duplication
too...
Bug: http://b/30988271
Change-Id: I4de58a94a22a4b1faf969a6fc70ca1560a4d5121
I've been meaning to do this for a while, and it came up on the bug below
that there have been conflicts with similar-named files in <base/*.h>,
so let's rule out one possible explanation.
Bug: http://b/27804373
Change-Id: I69e5d52b6260c573c308513420aee0e281426bd4
Also use ReadFully to replace read, because read can
return reading bytes less than requested. And use
WriteFully to replace write.
Bug: 26962895
Change-Id: Iff0b2bc6d925619a537f7fef682c2a7ad89a2dc2
