* commit '1642edb5208fe02ef64d5734fffaf7c4a724fd2f':
bionic: store property names as variable-length strings
bionic: prevent root processes from calling __system_property_add
bionic: revert to a single (larger) property area
bionic: reimplement property area as hybrid trie/binary tree
bionic: add missing memory barriers to system properties
bionic: make property area expandable
Names are immutable, so the fixed-sized arrays can be replaced with
variable-length ones to save memory (especially on internal tree nodes).
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 492ce95d9f6149137cb5b63c55cf2b3cdbe51e5e)
Change-Id: Ib074192d1b71150233d78c58e9ffcf7ecf688b6b
If a root process other than init calls __system_property_add, which
it should never do, it will break the design assumption that there is
only one mutator.
Pass O_EXCL to open() in map_prop_region_rw to ensure that only one
process ever has the property pages open for write.
(cherry picked from commit fb9b7b436f3ef94385f1b0c55ab81f246f0d96b8)
Change-Id: I6df3afedbfb5d07891b095aa24b78278381a5aaf
d329697 is too complicated. Change the multiple property pages back to
a single 128K property area that's mapped in entirely at initialization
(the memory will not get allocated until the pages are touched).
d329697 has other changes useful for testing (moving property area
initialization inside bionic and adding __system_property_set_filename)
so undo the change manually rather than with git revert.
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 5f05348c18286a2cea46eae8acf94ed5b7932fac)
Change-Id: I690704552afc07a4dd410277893ca9c40bc13e5f
See the comments for an explanation of how properties are stored.
The trie structure is designed to scale better than the previous
array-based implementation. Searching an array with n properties
required average O(n) string compares of the entire key; searching the
trie requires average O(log n) string compares of each token (substrings
between '.' characters).
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 6ac8e6a46d71a51bec16938efa89f275fa89cf7d)
Change-Id: Icbe31908572f33b4d9b85d5b62ac837cbd0f85e0
1) Reading the value must finish before checking whether it's intact
2) Setting the serial's dirty bit must visible before modifying the
value
3) The modified value must be visible before clearing the serial's dirty
bit
4) New properties and their TOC entries must be visible before updating
the property count
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 5bfa3ee8b37ef162154559575193018a6235acba)
Change-Id: Id3fa45261fc2df2ae493ab5194bc2b6bff04e966
The property area is initially one 4K region, automatically expanding as
needed up to 64 regions.
To avoid duplicating code, __system_property_area_init() now allocates
and initializes the first region (previously it was allocated in init's
init_property_area() and initialized in bionic). For testing purposes,
__system_property_set_filename() may be used to override the file used
to map in regions.
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit d32969701be070c0161c2643ee3c3df16066bbb8)
Change-Id: I038d451fe8849b0c4863663eec6f57f6521bf4a7
Names are immutable, so the fixed-sized arrays can be replaced with
variable-length ones to save memory (especially on internal tree nodes).
Change-Id: Iee77874b4b55b0f9c5e531d1334be7f7f40086d2
Signed-off-by: Greg Hackmann <ghackmann@google.com>
If a root process other than init calls __system_property_add, which
it should never do, it will break the design assumption that there is
only one mutator.
Pass O_EXCL to open() in map_prop_region_rw to ensure that only one
process ever has the property pages open for write.
Change-Id: I6b7c118e5e2fd2b92a2b168b8454fe9707325462
d329697 is too complicated. Change the multiple property pages back to
a single 128K property area that's mapped in entirely at initialization
(the memory will not get allocated until the pages are touched).
d329697 has other changes useful for testing (moving property area
initialization inside bionic and adding __system_property_set_filename)
so undo the change manually rather than with git revert.
Change-Id: I0ecb27843404f93af5489f15bfe657d65175e4f0
Signed-off-by: Greg Hackmann <ghackmann@google.com>
See the comments for an explanation of how properties are stored.
The trie structure is designed to scale better than the previous
array-based implementation. Searching an array with n properties
required average O(n) string compares of the entire key; searching the
trie requires average O(log n) string compares of each token (substrings
between '.' characters).
Change-Id: I491305bc7aca59609abcd871a5f33d97f89ce714
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Avoid keeping unnecessary file descriptors around when they're not
needed. Libc doesn't log so much that opening / closing overhead
matters.
Change-Id: I590ec5c27562db9bac025f781c48ec9a7724ce77
1) Reading the value must finish before checking whether it's intact
2) Setting the serial's dirty bit must visible before modifying the
value
3) The modified value must be visible before clearing the serial's dirty
bit
4) New properties and their TOC entries must be visible before updating
the property count
Change-Id: I26c680ec025fdb72362d5f618ec0d2b93d381233
Signed-off-by: Greg Hackmann <ghackmann@google.com>
The property area is initially one 4K region, automatically expanding as
needed up to 64 regions.
To avoid duplicating code, __system_property_area_init() now allocates
and initializes the first region (previously it was allocated in init's
init_property_area() and initialized in bionic). For testing purposes,
__system_property_set_filename() may be used to override the file used
to map in regions.
Change-Id: Ibe00ef52464bfa590953c4699a6d98383b0142b1
Signed-off-by: Greg Hackmann <ghackmann@google.com>
find_nth() will be inefficient on a trie. Since find_nth() is only used
internally and only for enumerating properties, we can add a foreach()
function to do this directly.
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 577418403d68e663fb33c7b0c8a90d862d9c00cf)
Change-Id: Iaca97d1182ce2c28863ba85241cbb5cf6185eb2f
find_nth() will be inefficient on a trie. Since find_nth() is only used
internally and only for enumerating properties, we can add a foreach()
function to do this directly.
Change-Id: I66bde9926c193073d74b244cce9fffd52108fff8
Signed-off-by: Greg Hackmann <ghackmann@google.com>
In 829c089f83ddee37203b52bcb294867a9ae7bdbc, we disabled all
FORTIFY_SOURCE support when compiling under clang. At the time,
we didn't have proper test cases, and couldn't easily create targeted
clang tests.
This change re-enables FORTIFY_SOURCE support under clang for a
limited set of functions, where we have explicit unittests available.
The functions are:
* memcpy
* memmove
* strcpy
* strncpy
* strcat
* strncat
* memset
* strlen (with modifications)
* strchr (with modifications)
* strrchr (with modifications)
It may be possible, in the future, to enable other functions. However,
I need to write unittests first.
For strlen, strchr, and strrchr, clang unconditionally calls the
fortified version of the relevant function. If it doesn't know the
size of the buffer it's dealing with, it passes in ((size_t) -1),
which is the largest possible size_t.
I added two new clang specific unittest files, primarily copied
from fortify?_test.cpp.
I've also rebuild the entire system with these changes, and didn't
observe any obvious problems.
Change-Id: If12a15089bb0ffe93824b485290d05b14355fcaa
Define __errordecl and replace __attribute__((__error__("foo")))
with __errordecl. Make sure __errordecl is a no-op on clang, as it
generates a compile time warning.
Change-Id: Ifa1a2d3afd6881de9d479fc2adac6737871a2949
Move the implementation of writing to the system property area
from init to bionic, next to the reader implementation. This
will allow full property testing to be added to bionic tests.
Add new accessor and waiting functions to hide the implementation
from watchprops and various bionic users.
Also hide some of the implementation details of the property area
from init by moving them into _system_properties.h, and other details
from everybody by moving them into system_properties.h.
(cherry picked from commit dc1038b7900acb664e99643d2974e1a0f4703781)
Change-Id: I192d3825ee276c5047bc751039fe6cfe226a7cca
