Presumably "bt" was "binary tree", but "trie_node" is a bit more
specific and removes the guesswork.
Test: treehugger
Change-Id: Ib5fb2dcbcf261ce516728099d484ed9cd6c069bd
This works (by reading /etc/localtime) on NetBSD, but not on Android
since we have no such file. Fix that by using our equivalent system
property instead.
Also s/time zone/timezone/ in documentation and comments. We've always
been inconsistent about this (as is upstream in code comments and
documentation) but it seems especially odd now we expose a _type_ that
spells it "timezone" to talk of "time zone" even as we're describing
that type and its associated functions.
Bug: https://github.com/chronotope/chrono/issues/499
Test: treehugger
Change-Id: I142995a3ab4deff1073a0aa9e63ce8eac850b93d
"nonplat" was renamed to "vendor" in Android Pie, but was retained
here for Treble compatibility.
We're now outside of the compatbility window for these devices so
it can safely be removed.
Test: build boot cuttlefish device. adb remount, modify
/system/etc/selinux/plat_sepolicy_and_mapping.sha256 to force
on-device policy compilation. reboot. Verify that device boots
without new selinux denials.
Change-Id: I663a524670120ee19dfe785aa5f89b3981bdd378
Revert submission 1403568-sysprop_trace
Reason for revert: makes property get/set non-reentrant
Reverted Changes:
I6f85f3f52:Add systrace tag for system property
Id2b93acb2:Adding system property tracing
Id78992d23:Add systrace tag for system property
I1ba9fc7bd:Add systrace tag for system property
Bug: 193050299
Test: build and boot a device
Change-Id: Ic7a83fb01a39113d408ed0c95d27f694d5a2649c
This log message exists to provide more context (the property name) to
SELinux denials for the same access check. The SELinux log severity
is 'W' since SELinux denials do not necessarily point to user-visible
errors, therefore this message should be 'W' as well.
Bug: 181269159
Test: build
Change-Id: Ie25091d96214a175b7ca39d5615f9a09b789d1e3
Android S devices must support eBPF.
Test: builds, atest, TreeHugger
Bug: 167500195
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I84a8d00f786fca8113dd3d555af279a1029f66f2
This benchmarks mapping property prefixes to property contexts with
two algorithms: the 'Legacy' method used before Android P and the
'Trie' used afterwards (the code in this directory).
It uses input mappings from both Oreo and the latest in AOSP ('S').
Note that there is nearly a 10x increase in the number of mappings in
S as there was in Oreo, which was predicted when the trie was
designed.
Results on cuttlefish:
-----------------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------------
LegacyLookupOreo 683576 ns 673538 ns 1060
LegacyLookupS 5683109 ns 5596982 ns 124
TrieLookupOreo 299851 ns 295696 ns 2378
TrieLookupS 584831 ns 576801 ns 1204
The results show that the legacy look up uses 8.3x more CPU time to
handle the number of mappings added through S, whereas the Trie lookup
uses less than 2x more CPU time, showing that the trie scales better
with added mappings.
Test: run this benchmark
Change-Id: I35c3aa4429f049e327a891f9cbe1901d8855d7ba
Introducing a new systrace tag, TRACE_TAG_SYSPROP, for use with
system property.
For property set, the tracing is added in __system_property_set() instead of
__system_property_update() / __system_property_add() so we can record
control properties like ctl.*, sys.powerctl.*, etc.., which won't be
updated via the latter two functions.
Bug: 147275573
Test: atest CtsBionicTestCases
Test: adb shell perfetto -o /data/misc/perfetto-traces/test_trace -t 10s bionic
Test: adb shell perfetto -o /data/misc/perfetto-traces/test_trace -t 10s sysprop
Test: adb shell /data/benchmarktest64/bionic-benchmarks/bionic-benchmarks \
--benchmark_filter=BM_property --bionic_cpu=4, then compares the results
of property benchmarks before and after the change, didn't see
significant difference.
Change-Id: Id2b93acb2ce02b308c0e4889f836159151af3b46
Merged-In: Id2b93acb2ce02b308c0e4889f836159151af3b46
(cherry picked from commit 26970c3493)
1) "fix the system properties design" is written for the old protocol,
so we've already changed the design. There are no other further
planned changes.
2) "don't drag in all the macros, just the types." is not likely to
happen or be particularly impactful.
3) "Find a location suitable for these functions ..." is refering to
legacy code. More likely that this code will be removed before we
find a serious reason to fix this TODO.
4) "(73062966) We still don't have a good way ..." is stale; we fixed
this bug and added the appropriate mechanism.
Test: n/a
Change-Id: I23991692cdeb81ad00844a6a1680900ff384208b
Right now, when we read a system property, we first (assuming we've
already looked up the property's prop_info) read the property's serial
number; if we find that the low bit (the dirty bit) in the serial
number is set, we futex-wait for that serial number to become
non-dirty. By doing so, we spare readers from seeing partially-updated
property values if they race with the property service's non-atomic
memcpy to the property value slot. (The futex-wait here isn't
essential to the algorithm: spinning while dirty would suffice,
although it'd be somewhat less efficient.)
The problem with this approach is that readers can wait on the
property service process, potentially causing delays due to scheduling
variance. Property reads are not guaranteed to complete in finite time
right now.
This change makes property reads wait-free and ensures that they
complete in finite time in all cases. In the new approach, we prevent
value tearing by backing up each property we're about to modify and
directing readers to the backup copy if they try to read a property
with the dirty bit set.
(The wait freedom is limited to the case of readers racing against
*one* property update. A writer can still delay readers by rapidly
updating a property --- but after this change, readers can't hang due
to PID 1 scheduling delays.)
I considered adding explicit atomic access to short property values,
but between binary compatibility with the existing property database
and the need to carefully handle transitions of property values
between "short" (compatible with atomics) and "long" (incompatible
with atomics) length domains, I figured the complexity wasn't worth it
and that making property reads wait-free would be adequate.
Test: boots
Bug: 143561649
Change-Id: Ifd3108aedba5a4b157b66af6ca0a4ed084bd5982
Enable native bridge support for bionic libraries.
Makes it possible to use them in binaries for translated
architectures.
Bug: http://b/77159578
Test: make
Change-Id: Iccd4ad7aecfa5260cc15f09ca975d2e18987278a
The log priorities and ids are in an NDK header, available to everyone.
Move CHECK into its own header for now. This would be better if it was
more like the <android-base/logging.h> CHECK family, but I don't have an
easy way to do that without lots of copy & paste, so punting for now.
Bug: https://issuetracker.google.com/issues/119713191
Test: boots
Change-Id: I4566be8a0a024fede0e2d257c98b908ec67af2a8
Use <android-base/macros.h> instead where possible, and move the bionic
macros out of the way of the libbase ones. Yes, there are folks who manage
to end up with both included at once (thanks OpenGL!), and cleaning that
up doesn't seem nearly as practical as just making this change.
Bug: N/A
Test: builds
Change-Id: I23fc544f39d5addf81dc61471771a5438778895b
We've copied & pasted these to too many places. And if we're going to
have another go at upstreaming these, that's probably yet another reason
to have the *values* in just one place. (Even if upstream wants different
names, we'll likely keep the legacy names around for a while for source
compatibility.)
Bug: http://b/111903542
Test: ran tests
Change-Id: I8ccc557453d69530e5b74f865cbe0b458c84e3ba
With the goal of disallowing exit time destructors, SystemProperties's
non-trivial destructor needs to be removed. This means replacing the
union hack with yet another hack as we don't want to allocate anything
despite relying on some polymorphism.
Bug: 73485611
Test: boot bullhead
Change-Id: I64223714c9b26c9724bfb8f3e2b0168e47b56bc8
We've been using #pragma once for new internal files, but let's be more bold.
Bug: N/A
Test: builds
Change-Id: I7e2ee2730043bd884f9571cdbd8b524043030c07
There were a bunch more unreasonable/incorrect ones, but these ones
seemed legit. Nothing very interesting, though.
Bug: N/A
Test: ran tests, benchmarks
Change-Id: If66971194d4a7b4bf6d0251bedb88e8cdc88a76f
Reinitializing system properties can result in crashes later in the
program, and is generally not recommended or even supported. This
change moves the actual logic for system properties into a class that
can be tested in isolation, without reinitializing the actual system
property area used in libc.
Bug: 62197783
Test: boot devices, ensure properties work
Test: system property unit tests and benchmarks
Change-Id: I9ae6e1b56c62f51a4d3fdb5b62b8926cef545649
This needs more work before it can be enabled.
Bug: 36001741
Test: boot, check that we're using old style properties
Change-Id: I7032f4b4224758b187cf4e8a53fd8845466a5d4a
This adds support for reading a serialized
/dev/__properties__/property_info file, which contains a
serialized trie that maps property names to the SELinux context to
which they belong.
Performance wise on walleye, this change reduces the start up cost in
libc from ~3000us to ~430us. On a benchmark that calls
__system_property_find() for each property set on the system, it
reduces the time per iteration from ~650us to ~292us.
Bug: 36001741
Test: Boot bullhead, walleye, run unit tests
Test: Benchmark initialization and lookup performance
Change-Id: I0887a3a7da88eb51b6d1bd494fa5bce593423599
Previously, the functionality for mapping properties to contexts were
broken into a set of classes, each statically defined in
system_properties.cpp to prevent using new/malloc. This is a mistake
however, since system property initialization happens before static
initialization, so it is possible for the Constructors of these
classes to clobber the initialized data.
This change fixes that by placing them in a Union and having that
Union have a no-op constructor. The individual classes will be
initialized via placement new before they are used as is typically
done with classes in a union.
Test: boot bullhead
Change-Id: Ideb9d6ad8b6fc768811d8615d005cd4b8d134bce
pa_size should be static to prop_area, so make it so.
__system_property_area__ was reused for various purposes, but
realistically is a deprecated symbol and this finally separates us
from it.
Bug: 36001741
Test: boot bullhead, system property unit tests
Change-Id: I39663cc3b613093fa4c728b21d8ba58754f8e105
system_properties.cpp is a little bit unmanageable in its current
form, and is overdue for a refactoring into more clearly defined
components.
Of particular interest, is creating of a Contexts interface that
handles mapping of system property name -> SEContext and its
associated prop_area, and creating two classes that implement the
current and legacy functionality. This is needed as there will likely
be a third even newer way to do this mapping.
Bug: 36001741
Test: boot bullhead, system property unit tests
Change-Id: Ie75ec6fea1a95f90813918f54669d533e51327c6
