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 fb9b7b436f)
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 5f05348c18)
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 6ac8e6a46d)
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 5bfa3ee8b3)
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 d32969701b)
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>
Deliberately put items several levels deep in the trie hierarchy to test
the trie traversal
Change-Id: Id3cbd2e7d3500216b1ac8025eac70c0939622903
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>
Text relocations unnecessarily mark pages as dirty, preventing them
from being swapped out, wasting memory. Also, text relocations
prevent the code from running on certain hardened systems.
Print a message in logcat and stderr when we see a text relocation,
to encourage developers to fix their code.
Change-Id: I6051a7463911e090ae5727a355397d539669d5b9
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 577418403d)
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>
