- Show which executable is being linked, which linker config file is
being read, and which section in it is being used with, enabled on
$LD_DEBUG>=1.
- Show more info to follow the dlopen() process, enabled with "dlopen"
in the debug.ld.xxx property.
Test: Flash, boot, and look at logcat after "adb shell setprop debug.ld.all dlopen"
Bug: 120430775
Change-Id: I5441c8ced26ec0e2f04620c3d2a1ae860b792154
The *.mountpoint targets that installs /bionic/lib/lib*.so and
/bionic/bin/linker* are no longer needed.
Now, /system/lib/lib*.so and /system/bin/linker* are simply symlinks to
the corresponding files in the runtime apex. For example,
/system/lib/libc.so -> /apex/com.android.runtime/lib/bionic/libc.so
This is made possible because we now activate APEXes even before the
data partition is mounted. Before the data partition mounting, the
APEXes from the system partition are ativated. After the data partition
is mounted, updated APEXes in the partition (if any) are activated. As a
result, the symlink always points to the valid path regardless of
whether /data is mounted or not.
Bug: 125549215
Test: device boots
Change-Id: Ie7d83686abe00b3c436f9f9db75d4244200a0fc9
Make the num_free_blocks calculation clearer. There are
sizeof(page->bytes) bytes available for blocks, which is equal to
(kAllocateSize - 16). The previous calculation overestimates the amount
of space by 8 or 12 bytes, but that doesn't change the result because
both kAllocateSize and block_size_ are multiples of 16.
Bug: none
Test: boot device, bionic unit tests
Change-Id: Ia880cd5abc2a7bb4e9e6a8c0441d985f4df8fdc4
The tlsdesc_resolver_dynamic function is only defined on arm64, but the
code was taking its address on all targets. (Apparently the optimizer was
removing the entire deferred_tlsdesc_relocs loop?)
Bug: none
Test: bionic unit tests
Test: add -O0 to cc_defaults in linker/Android.bp, device boots
Change-Id: I899c78018cbe82aeaca7856c9f7b04300c1d3196
It's possible and sometimes beneficial for a library to have disjoint mappings
and for other libraries to be mapped into the gap between the mappings using
ANDROID_DLEXT_RESERVED_ADDRESS. See for example the proposal for partitioning
in lld [1].
Because the find_containing_library and do_dl_unwind_find_exidx functions use
a simple bounds check to figure out whether a pointer belongs to a library
they will, given a pointer into a library mapped into the gap of a library
with disjoint mappings, return a pointer to the soinfo for the outer library
instead of the inner one, because the outer library will appear before the
inner one in the solist.
From a user perspective this means that we won't be able to unwind the inner
library's frames on 32-bit ARM with libgcc, dladdr() will return information
for the outer library given a pointer to the inner one and dlopen() et al will
use the linker namespace of the outer library when called from the inner one
(although they will usually be the same).
To make this work correctly, make it so that once find_containing_library
sees a match for the bounds check, it examines the library's PT_LOADs to
make sure that there is a mapping for the given address. This is similar
to how libgcc and libunwind_llvm already handle finding the PT_GNU_EH_FRAME
on non-ARM32 platforms [2,3]. do_dl_unwind_find_exidx is reimplemented in
terms of find_containing_library.
[1] http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html
[2] e739ac0e25/libunwind/src/AddressSpace.hpp (L523)
[3] https://android.googlesource.com/toolchain/gcc/+/master/gcc-4.9/libgcc/unwind-dw2-fde-dip.c#294
Test: /data/nativetest{,64}/bionic-unit-tests/bionic-unit-tests on walleye-userdebug
Change-Id: I368fe6ad3c470b3dff80f7d9b04253566d63a7d2
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
Life is easier if we just keep test code in the same directory as the
stuff it's testing...
Test: tests still build and pass
Change-Id: I9b35d689098bdc28a71d69645b0ca9fdd6ea0108
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
Bug: http://b/116873221
The coverage library, which depends on libc, cannot link with libraries
since they opt of libc.
Test: m NATIVE_COVERAGE=true COVERAGE_PATHS=bionic
Change-Id: Iaaca8bc30c8ba59e5d4f7092b1a0fce8e8c14c72
The change is a workaround of app compat issue until the app fixes the
issue.
Likely, the app does not only dlopen(), but open() the libicuuc.so
with the absolute path.
Note that platform uses the stub libandroidicu.so, not libicuuc directly.
This CL topic moves (not duplicates) libandroidicu from /system to
/apex. Even though /system/lib/libicuuc.so is kept in the default
namespace, but no one should be using it.
Some debug info after this CL:
$ adb shell cat /proc/<zygote pid>/maps | grep libicuuc
$ adb shell cat /proc/<app pid>/maps | grep libicuuc
Only /apex/com.android.runtime/lib64/libicuuc.so is found, not the
/system.
Bug: 124218500
Test: The app can be launched successfully
Test: CtsJniTestCases
Change-Id: I67a50f0ad934be567a63d4038215546c9b4e5f7e
Some of the greylist libraries can be in directories other than
/system/lib. For example, libnativehelper.so is moved from the directory
to /apex/com.android.runtime/lib.
Previous behavior for greylist libraries is to find the lib under
/system/lib while "within" the current namespace which is usually the
classloader-namespace. Since the libs no longer exist there, linker
fails to load it and no further attempt is made.
This change fixes the problem by loading the greylist libs "from" the
default namespace. Since there is a link from the default namespace to
the namespace where the moved libraries are intended to be loaded (e.g.,
the 'runtime' namespace for libnativehelper.so), the call is successful.
Bug: 124201397
Test: bionic-unit-tests
Change-Id: I11d15993d18896bdf663c408f9e40d8a607c9b80
When the linker is invoked on itself, (`linker64 /system/bin/linker64`),
the linker prints an error, because self-invocation isn't allowed. The
current method for detecting self-invocation fails because the second
linker instance can crash in a constructor function before reaching
__linker_init.
Fix the problem by moving the error check into a constructor function,
which finishes initializing libc sufficiently to call async_safe_fatal.
The only important thing missing is __libc_sysinfo on 32-bit x86. The aux
vector isn't readily accessible, so use the fallback int 0x80.
Bug: http://b/123637025
Test: bionic unit tests (32-bit x86)
Change-Id: I8be6369e8be3938906628ae1f82be13e6c510119
This reverts commit 1906e77665
and fixes dlopen(nullptr)
It's enabled for the following .so libraries
libicuuc.so
libicui18n.so
This CL does not move the .so files into a APEX.
Thus, no visible effect before moving .so files.
Bug: 121248172
Test: dlfcn#dlopen_from_nullptr
Test: Perform the following test after moving libicuuc to /apex
dlopen("/system/lib64/libicuuc.so") for targetSdkVersion < Q
Change-Id: Ia310ea566485fe00ca28e2203f4bffbd92243638
It's enabled for the following .so libraries
libicuuc.so
libicui18n.so
This CL does not move the .so files into a APEX.
Thus, no visible effect before moving .so files.
Bug: 121248172
Test: Perform the following test after moving libicuuc to /apex
dlopen("/system/lib64/libicuuc.so") for targetSdkVersion < Q
Change-Id: Ic00d281d59de924c01582c48d2a946e3f5f33a09
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 dynamic linker installed to /system partition is only for
bootstraping, i.e. to be used only by early processes. The existing path
/system/bin/linker[64] will be a symlink to the mount pointpoint
/bionic/bin/linker[64] which will be bind-mounted with either the
bootstrap linker or the default linker in the runtime APEX. Since the
path is taken by the symlink, bootstrap linker is moved to ./boostrap
subdirectory.
Bug: 120266448
Test: m linker; the linker is found under /system/bin/bootstrap/
Change-Id: I163e0c8a1738b94565a6b60f48e65841ba058a91
This change adds following files and symlinks:
Files:
/bionic/lib[64]/lib{c|dl|m}.so
/bionic/bin/linker[64]
Symlinks:
/system/lib[64]/lib{c|dl|m}.so -> /bionic/lib[64]/lib{c|dl|m}.so
/system/bin/linker[64] -> /bionic/bin/linker[64]
/system/bin/linker_asan[64] -> /bionic/bin/linker[64]
The files serve as mount points for either the bootstrap Bionic or the
default Bionic from the runtime APEX. init does the bind-mounting during
booting.
The symlinks are there to not change the ordinary paths to the bionic
files; there are many places that the paths are implied or hard-coded,
e.g., dlopen("/system/lib/libc.so") or DT_INTERP pointing to
/system/bin/linker in the vendor prebuilts.
Bug: 120266448
Test: m blueline, cf_x86, aosp_arm
The aforementioned files and symlinks are found
Change-Id: I97e38c29409ac0610dde285db8df6e94a7930094
Each TLSDESC relocation relocates a 2-word descriptor in the GOT that
contains:
- the address of a TLS resolver function
- an argument to pass (indirectly) to the resolver function
(Specifically, the address of the 2-word descriptor is passed to the
resolver.)
The loader resolves R_GENERIC_TLSDESC relocations using one of three
resolver functions that it defines:
- tlsdesc_resolver_static
- tlsdesc_resolver_dynamic
- tlsdesc_resolver_unresolved_weak
The resolver functions are written in assembly because they have a
restrictive calling convention. They're only allowed to modify x0 and
(apparently) the condition codes.
For a relocation to memory in static TLS (i.e. the executable or an solib
loaded initially), the loader uses a simple resolver function,
tlsdesc_resolver_static, that returns the static offset it receives from
the loader.
For relocations to dynamic TLS memory (i.e. memory in a dlopen'ed solib),
the loader uses tlsdesc_resolver_dynamic, which allocates TLS memory on
demand. It inlines the fast path of __tls_get_addr, then falls back to
__tls_get_addr when it needs to allocate memory. The loader handles these
dynamic TLS relocations in two passes:
- In the first pass, it allocates a table of TlsDynamicResolverArg
objects, one per dynamic TLSDESC relocation.
- In the second pass, once the table is finalized, it writes the
addresses of the TlsDynamicResolverArg objects into the TLSDESC
relocations.
tlsdesc_resolver_unresolved_weak returns a negated thread pointer so that
taking the address of an unresolved weak TLS symbols produces NULL.
The loader handles R_GENERIC_TLSDESC in a target-independent way, but
only for arm64, because Bionic has only implemented the resolver functions
for arm64.
Bug: http://b/78026329
Test: bionic unit tests
Test: check that backtrace works inside a resolver function and inside
__tls_get_addr called from a resolver
(gdbclient.py, b __tls_get_addr, bt)
Merged-In: I752e59ff986292449892c449dad2546e6f0ff7b6
Change-Id: I752e59ff986292449892c449dad2546e6f0ff7b6
Initialize a thread's DTV to an empty zeroed DTV. Allocate the DTV and
any ELF module's TLS segment on-demand in __tls_get_addr. Use a generation
counter, incremented in the linker, to signal when threads should
update/reallocate their DTV objects.
A generation count of 0 always indicates the constant zero DTV.
Once a DTV is allocated, it isn't freed until the thread exits, because
a signal handler could interrupt the fast path of __tls_get_addr between
accessing the DTV slot and reading a field of the DTV. Bionic keeps a
linked list of DTV objects so it can free them at thread-exit.
Dynamic TLS memory is allocated using a BionicAllocator instance in
libc_shared_globals. For async-signal safety, access to the
linker/libc-shared state is protected by first blocking signals, then by
acquiring the reader-writer lock, TlsModules::rwlock. A write lock is
needed to allocate or free memory.
In pthread_exit, unconditionally block signals before freeing dynamic
TLS memory or freeing the shadow call stack.
ndk_cruft.cpp: Avoid including pthread_internal.h inside an extern "C".
(The header now includes a C++ template that doesn't compile inside
extern "C".)
Bug: http://b/78026329
Bug: http://b/123094171
Test: bionic unit tests
Change-Id: I3c9b12921c9e68b33dcc1d1dd276bff364eff5d7
Generalize the omitted symbol and missing-TLS-segment behaviors to all TLS
relocations.
R_GENERIC_TLS_DTPMOD is a module ID, which starts at 1 for the executable.
R_GENERIC_TLS_DTPREL is an offset from the start of a module to a specific
TLS symbol.
binutils currently disagrees with Bionic about the values of
R_AARCH64_TLS_DTPMOD64 and R_AARCH64_TLS_DTPREL64, so disable
DTPMOD/DTPREL for now on arm64.
Bug: http://b/78026329
Test: bionic unit tests (Tests for dynamic TLS will be added later)
Change-Id: I05c28d6a1036bdd6127f605036679b7475689445
These dynamic table entries are used for lazy relocation of TLSDESC
relocations. Bionic relocates everything eagerly and can ignore these
entries.
Bug: http://b/78026329
Test: bionic unit tests
Test: manual
Change-Id: I788c4a95041fae66de2fbeab3babe0205631999c
Rename LinkerMemoryAllocator -> BionicAllocator
Rename LinkerSmallObjectAllocator -> BionicSmallObjectAllocator
libc and the linker need to share an instance of the allocator for
allocating and freeing dynamic ELF TLS memory (DTVs and segments). The
linker also continues to use this allocator.
Bug: http://b/78026329
Test: /data/nativetest/bionic-unit-tests-static
Test: /data/nativetest64/bionic-unit-tests-static
Test: /data/nativetest/linker-unit-tests/linker-unit-tests32
Test: /data/nativetest64/linker-unit-tests/linker-unit-tests64
Change-Id: I2da037006ddf8041a75f3eba2071a8fcdcc223ce
The <async_safe/log.h> include in linker_allocator.h was made
unnecessary when the STL dependency was removed.
Replace the linker_*.h header includes with private/bionic_*.h
includes.
This change prepares LinkerMemoryAllocator for use in libc allocating
dynamic ELF TLS memory.
Bug: http://b/78026329
Test: bionic unit tests
Change-Id: I6ad62bd513e71dd3f91a4b724a92b19a1eb6c3b4
Suppress the SELinux denial log spam by not calling realpath(3) when the
path does not exist or is not accessible for read, and then not auditing
access(2) failure.
Bug: 120996057
Test: copy ping to /data/local/tmp, run it, verify no errors
Test: run bionic-unit-tests, the tests pass
Change-Id: Ie6058bfc9524a9b5c50fc7183fdddea6a8fb9200
In addition to ORIGIN, LIB is now expanded to either lib or lib64
depending on the ABI in the DT_RUNPATH.
Test: To be added (can't be added to AOSP directly since there are
internal tests that have to be updated as well)
Change-Id: I34a8316f1765a27c731bc270ee25c0ce287d7eed
Given that the block allocator does not free allocated memory unless
all objects are freed, we can allocate a large chunk of memory at a
time. This gives us:
1. Higher space efficiency, especially when the objects being
allocated has a large size.
2. Much less mmap()/prctl() calls.
3. Much less vm_area_struct objects.
While this increases the size of virtual memory allocated, the number
of dirty pages would be unchanged or less.
Test result on a Go device:
- Zygote starts 24ms faster on average.
- Kernel vm_area_struct usage 138KB less, across the entire system.
Bug: 112073665
Test: Boot and check the result from 'showmap'.
Change-Id: Iece631a5081151dd1e5bf25dbddac9b264bcdcff
If all allocated memory from a block allocator is freed, it is a good
opportunity to purge all the pages allocated to reduce lingering dirty
pages.
Memory saving varies with the platform and what processes are running.
Measuring right after boot, this saves ~1.8MB on cuttelfish and ~1.3MB
on a 32-bit ARM device.
Bug: 112073665
Test: Boot and check memory usage with 'showmap'.
Change-Id: I53769e0ec9699f0b3645cdf281a2c0bbffb98676
The field was pointing into an element of an std::vector, but the address
of a vector element is invalidated when the vector is resized.
This bug was caught by the new elftls.shared_ie and
elftls_dl.dlopen_shared_var_ie tests.
Bug: http://b/78026329
Test: bionic unit tests
Change-Id: I7232f6d703a9e339fe8966a95b7a68bae2c9c420
* changes:
Handle R_GENERIC_TLS_TPREL relocations
Avoid a dlopen abort on an invalid TLS alignment
Initialize static TLS memory using module list
Record TLS modules and layout static TLS memory
StaticTlsLayout: add exe/tcb and solib layout
Avoids some unnecessary work during dlopen/dlclose/dlsym for most
cases.
Bug: 122471935
Test: fewer page faults during app startup
Change-Id: Ie886e1e671066af3c6f3a895f9a8126f209d6660
This relocation is used for static TLS's initial-exec (IE) accesses.
A TLS symbol's value is its offset from the start of the ELF module's
TLS segment. It doesn't make sense to add the load_bias to this value,
so skip the call to soinfo::resolve_symbol_address.
Allow TLS relocations to refer to an unresolved weak symbol. In that case,
sym will be non-zero, but lsi will be nullptr. The dynamic linker resolves
the TPREL relocation to 0, making &missing_weak_symbol equal the thread
pointer.
Recognize Gold-style relocations to STB_LOCAL TLS symbols/sections and
issue an error.
Remove the "case R_AARCH64_TLS_TPREL64", because the R_GENERIC_TLS_TPREL
case handles it.
Remove the no-op R_AARCH64_TLSDESC handler. It's better to issue an error.
dlopen_library_with_ELF_TLS now fails with a consistent error about an
unimplemented dynamic TLS relocation.
Bug: http://b/78026329
Test: bionic unit tests (elftls tests are added in a later CL)
Change-Id: Ia08e1b5c8098117e12143d3b4ebb4dfaa5ca46ec
If the alignment of a TLS segment in a shared object is invalid, return
an error through dlerror() rather than aborting the process.
Bug: http://b/78026329
Test: bionic unit tests
Change-Id: I60e589ddd8ca897f485d55af089f08bd3ff5b1fa
It can happen e.g. if android_dlopen_ext is called with an absolute path to
a file that is not accessible in the current namespace. The first
load_library call in find_library_internal will then open the file and
assign its fd to the task and return false. Then linked namespaces are
searched, and load_library gets called again and opens the same file and
overwrites the fd in the task without closing it first. (In one of the later
calls the namespace config might very well allow the file to be loaded and
the android_dlopen_ext call eventually returns successfully, and the process
continues with the leaked fd.)
The code could perhaps be changed to avoid opening the file repeatedly in
these cases, but the LoadTask class should arguably keep its state clean
anyway.
Bug: 113373927
Test: Flash and boot device with (and without) http://r.android.com/812674,
which moves libart.so to the runtime namespace and thus makes it load
/system/framework/*/boot*.oat files across the namespace boundary from
runtime to default.
Change-Id: Iae91b7c743c5f3f973506153ba52898ae72e6fee
Replace reserve_tcb with reserve_exe_segment_and_tcb, which lays out both
the TCB and the executable's TLS segment, accounting for the difference in
layout between variant 1 and variant 2 targets.
The function isn't actually called with a non-null TlsSegment* yet.
Bug: http://b/78026329
Test: bionic unit tests
Change-Id: Ibd6238577423a7d0451f36da7e64912046959796
