Age | Commit message (Collapse) | Author |
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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
Merged-In: Ic7a83fb01a39113d408ed0c95d27f694d5a2649c
(cherry picked from commit 61a5a8380d6417e9b85bb2f6a4a694ef4222031f)
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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
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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 26970c34937e2339876d6ba335a56769d6f0d75e)
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This reverts commit de39d9242ae38733c33173957386db0b8060e52a.
Reason for revert: This revert is not needed
Change-Id: I34af8e5d75c724f6c4066fafbfc6bc7d58377601
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This reverts commit 0cf90556de2bde53a1957c5946036b2fe2e4e429.
Reason for revert: Device boot failures - 144355953
Change-Id: Icd4fc8c7a1d06d688a6d37e6f1c1aa45563f711b
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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
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Fixes -Wzero-as-null-pointer-constant warning.
Test: m
Bug: 68236239
Change-Id: I5b4123bc6709641315120a191e36cc57541349b2
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Bug: b/79117743
Test: /data/nativetest64/bionic-unit-tests/bionic-unit-tests
Change-Id: Idd5aa4d195abc13c06d3e5b57aef69a68c2a9a9d
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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
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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
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This reverts commit e149f3c1d7b6848af6a27e4089d5f0c915e1437d.
Reason for revert: This is ready to be enabled now.
Bug: 36001741
Change-Id: I418d3a498ff0712ce9a1857924c6d0039026a664
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This needs more work before it can be enabled.
Bug: 36001741
Test: boot, check that we're using old style properties
Change-Id: I7032f4b4224758b187cf4e8a53fd8845466a5d4a
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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
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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
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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
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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
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