This flag means "$ORIGIN processing required", and since we always
do that, we can claim support for it.
Change-Id: If60ef331963f6bc1e1818d7fa2ee57c1aa8fa343
To take advantage of file-backed huge pages for the text segments of key
shared libraries (go/android-hugepages), the dynamic linker must load
candidate ELF files at an appropriately aligned address and mark
executable segments with MADV_HUGEPAGE.
This patches uses segments' p_align values to determine when a file is
PMD aligned (2MB alignment), and performs load operations accordingly.
Bug: 158135888
Test: Verified PMD aligned libraries are backed with huge pages on
supporting kernel versions.
Change-Id: Ia2367fd5652f663d50103e18f7695c59dc31c7b9
This patch adds support to load BTI-enabled objects.
According to the ABI, BTI is recorded in the .note.gnu.property section.
The new parser evaluates the property section, if exists.
It searches for .note section with NT_GNU_PROPERTY_TYPE_0.
Once found it tries to find GNU_PROPERTY_AARCH64_FEATURE_1_AND.
The results are cached.
The main change in linker is when protection of loaded ranges gets
applied. When BTI is requested and the platform also supports it
the prot flags have to be amended with PROT_BTI for executable ranges.
Failing to add PROT_BTI flag would disable BTI protection.
Moreover, adding the new PROT flag for shared objects without BTI
compatibility would break applications.
Kernel does not add PROT_BTI to a loaded ELF which has interpreter.
Linker handles this case too.
Test: 1. Flame boots
2. Tested on FVP with BTI enabled
Change-Id: Iafdf223b74c6e75d9f17ca90500e6fe42c4c1218
Update a comment in android-changes-for-ndk-developers.md about the
removed debug.ld.greylist_disabled system property.
Update language to comply with Android's inclusive language guidance
#inclusivefixit
See https://source.android.com/setup/contribute/respectful-code for reference
Bug: http://b/162536543
Test: bionic-unit-tests
Change-Id: I760ee14bce14d9d799926c43d2c14fd8ffbc6968
The doc_link argument is really a URL fragment within the
android-changes-for-ndk-developers.md document, not a filename at the
root of the bionic repository.
Test: manual
Bug: none
Change-Id: I1b542e47aca132ce43ba1d50d83db1bf3c7b10c6
Symbol lookup is O(L) where L is the number of libraries to search (e.g.
in the global and local lookup groups). Factor out the per-DSO work into
soinfo_do_lookup_impl, and optimize for the situation where all the DSOs
are using DT_GNU_HASH (rather than SysV hashes).
To load a set of libraries, the loader first constructs an auxiliary list
of libraries (SymbolLookupList, containing SymbolLookupLib objects). The
SymbolLookupList is reused for each DSO in a load group. (-Bsymbolic is
accommodated by modifying the SymbolLookupLib at the front of the list.)
To search for a symbol, soinfo_do_lookup_impl has a small loop that first
scans a vector of GNU bloom filters looking for a possible match.
There was a slight improvement from templatizing soinfo_do_lookup_impl
and skipping the does-this-DSO-lack-GNU-hash check.
Rewrite the relocation processing loop to be faster. There are specialized
functions that handle the expected relocation types in normal relocation
sections and in PLT relocation sections.
This CL can reduce the initial link time of large programs by around
40-50% (e.g. audioserver, cameraserver, etc). On the linker relocation
benchmark (64-bit walleye), it reduces the time from 131.6ms to 71.9ms.
Bug: http://b/143577578 (incidentally fixed by this CL)
Test: bionic-unit-tests
Change-Id: If40a42fb6ff566570f7280b71d58f7fa290b9343
Validate the list of defined versions explicitly, during library
prelinking, rather than implicitly as part of constructing the
VersionTracker in soinfo::link_image.
Doing the validation upfront allows removing the symbol lookup failure
code paths, which only happen on a library with invalid version
information.
Helps on the walleye 64-bit linker relocation benchmark (146.2ms ->
131.6ms)
Bug: none
Test: bionic unit tests
Change-Id: Id17508aba3af2863909f0526897c4277419322b7
Anonymous namespace is not created separately. When a regular namespace
is created with ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS, that
namespace is used as the anonymous namespace.
Bug: 130388701
Test: CtsBionicTestCases
Change-Id: Ie449a59f303487a7a9ff6fff98e6148e9f968fd2
When relocating a DSO, it is not unusual to have consecutive
relocations using the same symbol. In this case, it is wasteful to
perform the same symbol lookup. This change implements an 1-entry
symbol cache so that symbol lookup results are reused in such scenario.
Test: On cuttlefish, enable STATS in linker_debug.h. Boot and see RELO
STATS in logcat showing cache hits. Hit rate seen is mostly
within 15% to 45%.
Change-Id: I84783d3b9a6ac9e39ed7fb45e58f6b3c012478d0
Ordinary executables have a PT_INTERP path of /system/bin/linker[64], but:
- executables using bootstrap Bionic use /system/bin/bootstrap/linker[64]
- ASAN executables use /system/bin/linker_asan[64]
gdb appears to use the PT_INTERP path for debugging the dynamic linker
before the linker has initialized the r_debug module list. If the linker's
l_name differs from PT_INTERP, then gdb assumes that the linker has been
unloaded and searches for a new solib using the linker's l_name path.
gdb may print a warning like:
warning: Temporarily disabling breakpoints for unloaded shared library "$OUT/symbols/system/bin/linker64"
If I'm currently debugging the linker when this happens, gdb apparently
doesn't load debug symbols for the linker. This can be worked around with
gdb's "sharedlibrary" command, but it's better to avoid it.
Previously, when PT_INTERP was the bootstrap linker, but l_name was
"/system/bin/linker[64]", gdb would find the default non-bootstrap linker
binary and (presumably) get confused about symbol addresses.
(Also, remove the "static std::string exe_path" variable because the
soinfo::realpath_ field is a std::string that already lasts until exit. We
already use it for link_map_head.l_name in notify_gdb_of_load.)
Bug: http://b/134183407
Test: manual
Change-Id: I9a95425a3a5e9fd01e9dd272273c6ed3667dbb9a
Introduce a new flag ANDROID_DLEXT_RESERVED_ADDRESS_RECURSIVE which
instructs the linker to use the reserved address space to load all of
the newly-loaded libraries required by a dlopen() call instead of only
the main library. They will be loaded consecutively into that region if
they fit. The RELRO sections of all the loaded libraries will also be
considered for reading/writing shared RELRO data.
This will allow the WebView implementation to potentially consist of
more than one .so file while still benefiting from the RELRO sharing
optimisation, which would otherwise only apply to the "root" .so file.
Test: bionic-unit-tests (existing and newly added)
Bug: 110790153
Change-Id: I61da775c29fd5017d9a1e2b6b3757c3d20a355b3
This is the second attempt to purge linker block allocators. Unlike the
previously reverted change which purge allocators whenever all objects
are freed, we only purge right before control leaves the linker. This
limits the performance impact to one munmap() call per dlopen(), in
most cases.
Bug: 112073665
Test: Boot and check memory usage with 'showmap'.
Test: Run camear cold start performance test.
Change-Id: I02c7c44935f768e065fbe7ff0389a84bd44713f0
The executable can be inside a zip file using the same syntax used for
shared objects: path.zip!/libentry.so.
The linker currently requires an absolute path. This restriction could be
loosened, but it didn't seem important? If it allowed non-absolute paths,
we'd need to decide how to handle:
- foo/bar (relative to CWD?)
- foo (search PATH / LD_LIBRARY_PATH, or also relative to CWD?)
- foo.zip!/bar (normalize_path() requires an absolute path)
The linker adjusts the argc/argv passed to main() and to constructor
functions to hide the initial linker argument, but doesn't adjust the auxv
vector or files like /proc/self/{exe,cmdline,auxv,stat}. Those files will
report that the kernel loaded the linker as an executable.
I think the linker_logger.cpp change guarding against (g_argv == NULL)
isn't actually necessary, but it seemed like a good idea given that I'm
delaying initialization of g_argv until after C++ constructors have run.
Bug: http://b/112050209
Test: bionic unit tests
Change-Id: I846faf98b16fd34218946f6167e8b451897debe5
* Initialize the exe's l_ld correctly, and initialize its l_addr field
earlier.
* Copy the phdr/phnum fields from the linker's temporary soinfo to its
final soinfo. This change ensures that dl_iterate_phdr shows the phdr
table for the linker.
* Change init_linker_info_for_gdb a little: use an soinfo's fields to
init the soinfo::link_map_head field, then reuse the new
init_link_map_head function to handle the linker and the executable.
Test: manual
Test: bionic-unit-tests
Bug: https://issuetracker.google.com/112627083
Bug: http://b/110967431
Change-Id: I40fad2c4d48f409347aaa1ccb98d96db89da1dfe
We've been using #pragma once for new internal files, but let's be more bold.
Bug: N/A
Test: builds
Change-Id: I7e2ee2730043bd884f9571cdbd8b524043030c07
This commit allows users to create a link without soname filters between
two linker namespaces.
The motivation is to establish one-way shared library isolation. For
example, assume that there are two linker namespaces `default` and
`vndk`. We would like to limit the shared libraries that can be used by
the `default` namespace. In the meanwhile, we would like to allow the
`vndk` namespace to use shared libs from the `default` namespace if the
soname cannot be find in the search path or loaded sonames of the `vndk`
namespace.
shared_libs = %VNDK_CORE_LIBRARIES%
shared_libs += %VNDK_SAMEPROCESS_LIBRARIES%
vndk <-------------------------------------------- default
\_______________________________________________/^
allow_all_shared_libs = true
android_link_namespaces_all_libs() is added to libdl, but it is
versioned as LIBC_PRIVATE. android_link_namespaces_all_libs() is only
for unit tests.
Bug: 69824336
Test: adb shell /data/nativetest/linker-unit-tests/linker-unit-tests32
Test: adb shell /data/nativetest64/linker-unit-tests/linker-unit-tests64
Test: adb shell /data/nativetest/bionic-unit-tests/bionic-unit-tests
Test: adb shell /data/nativetest64/bionic-unit-tests/bionic-unit-tests
Test: Update /system/etc/ld.config*.txt and check whether the vndk
linker namespace of the vendor process can access the shared libs from
the default linker namespace.
Change-Id: I2879f0c5f5af60c7e56f8f743ebd2872e552286b
Introduce new flag to mark soinfo as TLS_NODELETE when
there are thread_local dtors associated with dso_handle
belonging to it.
Test: bionic-unit-tests --gtest_filter=dl*
Test: bionic-unit-tests-glibc --gtest_filter=dl*
Bug: https://github.com/android-ndk/ndk/issues/360
Change-Id: I724ef89fc899788f95c47e6372c38b3313f18fed
This change also replaces elf-hash with gnu-hash.
Test: make
Test: bionic-unit-tests --gtest_filter=dl*:Dl*
Change-Id: Ibc4026f7abc7e8002f69c33eebaf6a193f1d22eb
greylist is needed only for application namepaces. Since we started using
linker-namesapces for vendors and other platform apps linker should not
enable greylist workaround by default.
Bug: http://b/37731053
Bug: https://issuetracker.google.com/38146125
Test: sailfish builds and boots
Test: bionic-unit-tests and linker-unit-tests pass
Change-Id: Iee83db6fb1ae754f5ade18491321d9bca3b5ead4
(cherry picked from commit e8ffe56a9c)
This library is used by a number of different libraries in the system.
Make it easy for platform libraries to use this library and create
an actual exported include file.
Change the names of the functions to reflect the new name of the library.
Run clang_format on the async_safe_log.cpp file since the formatting is
all over the place.
Bug: 31919199
Test: Compiled for angler/bullhead, and booted.
Test: Ran bionic unit tests.
Test: Ran the malloc debug tests.
Change-Id: I8071bf690c17b0ea3bc8dc5749cdd5b6ad58478a
Depending on how ld.config.txt is configured, there can be multiple
built-in namespaces created by the linker from the beginning of a
process. android_get_exported_namespace is a platform only API for
getting a handle (android_namespace_t*) to one of the built-in namespaces
with given name. The returned namespace can then be given to
android_dlopen_ext in order to explicitly specify the target namespace
where the library is searched and loaded from.
Note that this function only returns 'exported' namespaces created via
ld.config.txt file. In order to export a namespace, the visible property
should be set to true:
namespace.<name>.visible = true
Namespaces are hidden by default. Hidden namespaces and namespaces
that are created programmatically, notably 'classloader-namespace',
aren't returned by this function.
Bug: 36851137
Test: confirmed that namespaces created with ld.config.txt is retrieved.
Test: linker-unit-tests passes
Merged-in: I714b510fa24f77e42c3dfc4c827b3befa8bb2951
Change-Id: I0d05fa7e0e116009edf8ea362ab46774bc617cbf
(cherry picked from commit d7c4832e6a)
This commit updates interface of libdl.c.
1. android_init_namespaces is replaces with android_init_anonymous_namespace
2. added 2 arguments to android_create_namespace to specify linked namespace
and the list of shared libraries sonames.
3. symbol lookup does not get past boundary libraries (added check and test for it).
Bug: http://b/26833548
Bug: http://b/21879602
Test: bionic-unit-tests --gtest_filter=dl*:Dl*
Change-Id: I32921da487a02e5bd0d2fc528904d1228394bfb9
Do not hijack libdl.so methods but make libdl proxy calls to
loader instead. This will be replaces by calls to libc.so
once loader functionality is migrated.
Also add a lock to dl_unwind_find_exidx function call.
Test: bionic-unit-tests --gtest_filter=dl*:Dl*
Bug: http://b/27106625
Change-Id: Ic33a7109a86f4262798d63a35f4c61d15b0068bb
Do not hijack libdl.so methods but make libdl proxy calls to
loader instead. This will be replaces by calls to libc.so
once loader functionality is migrated.
Also add a lock to dl_unwind_find_exidx function call.
Test: bionic-unit-tests --gtest_filter=dl*:Dl*
Bug: http://b/27106625
Change-Id: I9e666e771e4bbca52151cfa7fc4c8677e1480818
DF_1_PIE is set in PIE code built with gcc 6.x. The flag is purely
informational and the linker doesn't need to do anything about it,
so Bionic handles it correctly - no need to warn.
Change-Id: If99c1742fe22f8842a84818909ed961716ef5ca5
Signed-off-by: Bernhard Rosenkränzer <Bernhard.Rosenkranzer@linaro.org>
Move soinfo and globals out of linker.cpp to
separate files.
Breaking up huge linker.cpp into smaller peaces
in order to make it easier to extract part of the
code that belongs to libdl.so and remove parts of
the code that do not belong to linker
(refactoring part 2 of many)
Change-Id: I868417f4b8d2b84d0e8265e354bc7977161497e2
Breaking up huge linker.cpp into smaller peaces
in order to make it easier to extract part of the
code that belongs to libdl.so and remove parts of
the code that do not belong to linker
(refactoring part 1 of many)
Change-Id: I57ac36677a815800dc127c8c45c3ea806c37e247
Test: bionic-unit-tests --gtest_filter=dl*:Dl*
The glibc implementation of the loader passes argc/argv/envp
to all elf constructors. This change makes bionic linker
behave in the same way.
Bug: http://b/30145768
Change-Id: I1c65c42aa5305a5b133c64b5748205bbde869e0e
Test: run bionic-unit-tests --gtest_filter=dl*:Dl*
This change implements the following property:
Any 2**N aligned memory region on size 2**N contains no more than one DSO.
The value N can be configured, with 16 or 18 looking like a good choice.
Additionally, DSOs are loaded at random page-aligned address inside these large
regions.
This change has dual purpose:
1. Larger values of N allow a lot more compact CFI shadow implementation.
See change I14dfea630de468eb5620e7f55f92b1397ba06217.
For example, CFI shadow for the system_server process has the following size (RSS, KB):
152 for N = 12, 32 for N = 16, 16 for N = 18.
2. Extra randomization is good for security.
This change does not result in extra RAM usage, because everything is still page-aligned.
It does result in a bit more VM fragmentation because of the gaps between shared libraries.
As it turns out, this fragmentation is barely noticeable because the kernel creates new mapping
at the highest possible address, and we do enough small mappings to almost completely fill the
gaps (ex. in the Zygote the gaps are filled with .ttf file mappings and thread stacks).
I've measured VM fragmentation as the sum of all VM gaps (unmapped regions) that are larger
than 1MB according to /proc/$PID/maps. On aosp_angler-userdebug, the numbers are (in GB):
| N = 12 | N = 18
system_server | 521.9 | 521.1
zygote64 | 522.1 | 521.3
zygote32 | 2.55 | 2.55
mediaserver | 4.00 | 4.00
Change-Id: Ia6df840dd409c82837efd1f263be420d9723c84a
This patch lets developers tune logging of dlopen/dlerror with
setting system property.
Note that for security purposes this option is disabled on user build
for non-debuggable apps.
For starters there are 3 debug options:
dlerror - enables logging of all dlerrors
dlopen - traces dlopen calls
To enable system-wide logging (works only for userdebug/eng builds)
use debug.ld.all property.
To enable logging for particular app use debug.ld.app.<appname> property.
Example: Running "adb shell setprop debug.ld.all dlerror,dlopen" will log all
dlerror message as well as trace all calls to dlopen.
Bug: http://b/29458203
Change-Id: I2392c80a795509e16fe5689d0500d18b99772a64
This change enables apps to share libraries opened
with RTLD_GLOBAL between different classloader namespaces.
The new parameter to create_namespace allows native_loader
to instruct the linker to share libraries belonging to
global group from a specified namespace instead of
using the caller_ns.
Bug: http://b/28560538
Bug: https://code.google.com/p/android/issues/detail?id=208458
Change-Id: I5d0c62730bbed19cdeb16c7559c74aa262a2475f
They are intended for platform use only and we shouldn't have them
in the public header file.
Bug: http://b/28174921
Change-Id: Ib9b3d0fa9442cfa2e784a693ad567d1444d774e5
linker didn't remove link to the soinfo from shared
namespaces on soinfo_unload, because it didn't keep
record of all namespaces the library is added to.
This change adds test for this and also fixes the
problem by introducing list of secondary namespaces
to soinfo, which is used to remove soinfo in
soinfo::remove_all_links().
Bug: http://b/28115950
Change-Id: Ifbf6e54f92fa6e88f86b6a8dd6dc22d4553afd22
Handle no longer is a pointer to soinfo of
a corresponding library. This is done to
prevent access to linker internal fields.
Bug: http://b/25593965
Change-Id: I62bff0d0e5b2dc842e6bf0babb30fcc4c000be24
This patch uses __kernel_vsyscall instead of "int 0x80"
as the syscall entry point. AT_SYSINFO points to
an adapter to mask the arch specific difference and gives a
performance boost on i386 architecture.
Change-ID: Ib340c604d02c6c25714a95793737e3cfdc3fc5d7
Signed-off-by: Mingwei Shi <mingwei.shi@intel.com>
