This reverts commits eb1b07469f and
d14dc3b87f, and fixes the bug where
we were calling mmap (which might cause errno to be set) before
__set_tls (which is required to implement errno).
Bug: 8557703
Change-Id: I2c36d00240c56e156e1bb430d8c22a73a068b70c
We notify debuggerd of problems by installing signal handlers. That's
fine except for when the signal is caused by us running off the end of
a thread's stack and into the guard page.
Bug: 8557703
Change-Id: I1ef65b4bb3bbca7e9a9743056177094921e60ed3
Kernel provides virtual DSO for stack unwinding/exception handlind info for
signal usage case. Stack unwinding routines use 'dl_iterate_phdr' function
for additional DWARF info gathering from DSOs. Patch enables virtual DSO
enumeration via dl_iterate_phdr function.
Signed-off-by: Sergey Melnikov <sergey.melnikov@intel.com>
Change-Id: Ic2882b28f40b456a088bc1e63c50cbfda7e4a102
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
This matches glibc and makes life easier for developers who want to
sometimes preload a library from init (which has no conditionals); they
can simply move/remove the library to disable.
Change-Id: I579b8633f958235af6e46bb53b378b9e363afb1f
* commit '98f7659d7e3a7d75c68a41299f6ee55d7d35c27b':
Don't fail to run DT_INIT and DT_INIT_ARRAY constructors if a shared library has DT_PREINIT_ARRAY constructors.
The GNU dynamic linker silently ignores a DT_PREINIT_ARRAY section
in a shared library. We had ineffectual code that tried to report
an error, which I tried to fix but got wrong --- my version still
wouldn't report the error to the caller, but would prevent us from
continuing to call constructors.
Bug: 8825226
Change-Id: I4fd8450ecc44d8767a1cb808aeecfbfbfc77c070
get_AT_SECURE() was getting called before linker_env_init() had
been called, and returning the default value ("true"). This was
causing us to reopen closed stdin, stdout, and stderr for ALL
processes, not just privileged (setuid) processes.
Calling path:
- __linker_init
- soinfo_link_image
- get_AT_SECURE
- __linker_init_post_relocation
- linker_env_init
This change restores the intended behavior of only re-opening
stdin, stdout, and stderr for privileged processes.
Change-Id: I8b085ea6597710ac4c1a3c93f1bf8b81eecb08c0
This adds __libc_fatal, cleans up the internal logging code a bit more,
and switches suitable callers over to __libc_fatal. In addition to logging,
__libc_fatal stashes the message somewhere that the debuggerd signal handler
can find it before calling abort.
In the debuggerd signal handler, we pass this address to debuggerd so that
it can come back with ptrace to read the message and present it to the user.
Bug: 8531731
Change-Id: I416ec1da38a8a1b0d0a582ccd7c8aaa681ed4a29
We only need one logging API, and I prefer the one that does no
allocation and is thus safe to use in any context.
Also use O_CLOEXEC when opening the /dev/log files.
Move everything logging-related into one header file.
Change-Id: Ic1e3ea8e9b910dc29df351bff6c0aa4db26fbb58
Still chipping away at the situation where every variable in the
linker was of type 'unsigned'. This patch switches counts over to
being size_t and adds an explicit type for init/fini function pointers
and arrays of function pointers.
Also improve logging from CallArray.
Also remove trailing "\n"s from log messages.
Change-Id: Ie036d2622caac50f4d29f0570888bb527661d77e
There's now only one place where we deal with this stuff, it only needs to
be parsed once by the dynamic linker (rather than by each recipient), and it's
now easier for us to get hold of auxv data early on.
Change-Id: I6314224257c736547aac2e2a650e66f2ea53bef5
Replace a kernel header file dependency with files from NetBSD.
They're more complete, and ELF is ELF, whether you're on Linux or a BSD.
Bug: 7973611
Change-Id: I83ee719e7efdf432ec2ddbe8be271d05b2f558d7
We had two copies of the backtrace code, and two copies of the
libcorkscrew /proc/pid/maps code. This patch gets us down to one.
We also had hacks so we could log in the malloc debugging code.
This patch pulls the non-allocating "printf" code out of the
dynamic linker so everyone can share.
This patch also makes the leak diagnostics easier to read, and
makes it possible to paste them directly into the 'stack' tool (by
using relative PCs).
This patch also fixes the stdio standard stream leak that was
causing a leak warning every time tf_daemon ran.
Bug: 7291287
Change-Id: I66e4083ac2c5606c8d2737cb45c8ac8a32c7cfe8
The linker is essentially a shared library, and incorporates
it's own copy of libc. Even though it's unnecessary, currently
/system/bin/linker is exporting various libc symbols (only to
apps which explicitly dlopen /system/bin/linker)
Add --exclude-libs,ALL, which tells the static linker to mark
all of the imported libc symbols as hidden. This reduces the
size of /system/bin/linker from 92K to 67K with no obvious
loss in functionality.
$ adb shell ls -l /system/bin/linker
-rwxrwxrwx root root 92260 2013-01-16 16:52 linker
$ adb shell ls -l /system/bin/linker
-rwxrwxrwx root root 67660 2013-01-16 16:49 linker
Documentation on exclude-libs can be found at
http://sourceware.org/binutils/docs-2.21/ld/Options.html
Change-Id: I4508287770e4b7a845def2e6b4af969f9c866c6a
The AT_RANDOM changes broke setuid / setgid executables
such as "ping". When the linker executes a setuid program,
it cleans the environment, removing any invalid environment
entries, and adding "NULL"s to the end of the environment
array for each removed variable. Later on, we try to determine
the location of the aux environment variable, and get tripped
up by these extra NULLs.
Reverting this patch will get setuid executables working again,
but getauxval() is still broken for setuid programs because of
this bug.
This reverts commit e3a49a8661.
Change-Id: I05c58a896b1fe32cfb5d95d43b096045cda0aa4a
Populate the stack canaries from the kernel supplied
AT_RANDOM value, which doesn't involve any system calls.
This is slightly faster (6 fewer syscalls) and avoids
unnecessarily reading /dev/urandom, which depletes entropy.
Bug: 7959813
Change-Id: If2b43100a2a9929666df3de56b6139fed969e0f1
When executing a setuid executable, filter out ANDROID_PROPERTY_WORKSPACE
from the environment. Some applications implicitly trust the property
space and don't realize that it's passed by an environment variable
which can be modified by the caller.
Change-Id: I3e3a98941f0a1f249a2ff983ecbcfe1278aa9159
This is primarily for MIPS exutables that do not have a
DT_MIPS_RLD_MAP entry.
Change-Id: I4c221d92debcfed961eeee2515123f3fb21ec8e6
Signed-off-by: Chris Dearman <chris@mips.com>
This patch replaces .S versions of x86 crtfiles with .c which are much
easier to support. Some of the files are matching .c version of Arm
crtfiles. x86 files required some cleanup anyway and this cleanup actually
led to matching Arm files.
I didn't change anything to share the same crt*.c between x86 and Arm. I
prefer to keep them separate for a while in case any change is required
for one of the arch, but it's good thing to do in the following patches.
Change-Id: Ibcf033f8d15aa5b10c05c879fd4b79a64dfc70f3
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
If you need to build your own linker to get debugging, the debugging
is never available when you need it.
Change-Id: I5ff7e55753459d49a2990f25d9aa155e0b8602e0
According ELF spec re. DT_SYMBOLIC:
This element's presence in a shared object library alters the dynamic
linker's symbol resolution algorithm for references within the library.
Instead of starting a symbol search with the executable file, the
dynamic linker starts from the shared object itself. If the shared
object fails to supply the referenced symbol, the dynamic linker then
searches the executable file and other shared objects as usual.
This change implements the last part.
Change-Id: Iae95d53d455313a4306f11733941bcd3596ac85f
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
NVIDIA binary blobs construct strings to pass to dlopen(3) that
contain '/' but require that we fall back to LD_LIBRARY_PATH.
Change-Id: Iad831899986baace6962f4b335eeb288250a1e22
We'll need a lot more refactoring of this code before we can reduce
the granularity, but this is a step forward.
Change-Id: I07061720e734b571a8399c1d5b4f2f35cd681307
Request memory from the system when needed instead of having a fixed
array for soinfo structs. Note that malloc() et al can't be used in
linker, so use mmap() instead.
Change-Id: I4b495995931d7752b0e8c944e64d1fe41b9f7144
Also ensure that dlopen(3) errors always include the name of the library we
failed to open.
Also fix a bug where we'd fall back to searching LD_LIBRARY_PATH and the
built-in paths for names that include slashes.
Bug: http://code.google.com/p/android/issues/detail?id=38479
Change-Id: Ib2c009ed083344a7a012749d58f8679db2f26c78
If an executable contain copy relocations, other references
to the symbol it points to should be preempted and made to
point to the copy instead.
Also, the linker should make sure the target area has
sufficient space to contain the copy. It also checks
whether the library that supplies the symbol is built
with -Bsymbolic, and errors out if this is the case.
Change-Id: If135c83590092741cfd8f82f54816f363a4a4a3b
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@gmail.com>
I still want to break linker_format out into its own library so we can reuse
it for malloc debugging and so forth. (There are many similar pieces of code
in bionic, but the linker's one seems to be the most complete/functional.)
Change-Id: If3721853d28937c8e821ca1d23cf200e228a409a
error: C99 designator 'name' outside aggregate initializer
G++ 4.7+ can't handle some of C99 designated initializers.
Most likely it's just not implemented yet. Other possible workarounds is
to compile this as C not C++ or define name as char* instead of char[SIZE].
Appeared after this change https://android-review.googlesource.com/#/c/44470
Change-Id: Ib28157848ce759b8bb5dbb2ac0d9a768fa4e5107
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
I gave up trying to use the usual thread-local buffer idiom; calls to
calloc(3) and free(3) from any of the "dl" functions -- which live in
the dynamic linker -- end up resolving to the dynamic linker's stubs.
I tried to work around that, but was just making things more complicated.
This alternative costs us a well-known TLS slot (instead of the
dynamically-allocated TLS slot we'd have used otherwise, so no difference
there), plus an extra buffer inside every pthread_internal_t.
Bug: 5404023
Change-Id: Ie9614edd05b6d1eeaf7bf9172792d616c6361767
Add unit tests for dlerror(3) in various situations. I think We're at least
as good as glibc now.
Also factor out the ScopedPthreadMutexLock and use it here too.
Bug: http://code.google.com/p/android/issues/detail?id=38398
Change-Id: I040938b4366ab836e3df46d1d8055b92f4ea6ed8
Now we use private variables in transform-o-to-executable to support
build executables against the NDK.
Bug: 7170098
Change-Id: I6e505b33001b76f4b11fcbbb1d35392c4ddf4c70
Our debugger signal catcher expects to receive three args, but if
somebody cleared SA_SIGINFO we only get one, and bad things happen
when we try to use the second one. Test to see if SA_SIGINFO is
still set before we try to use the argument.
(cherry-pick of f84bc8d6f6368f1c846124a8168761ee8cc589c0.)
Bug: 7272866
Change-Id: I69a65c25e833aea70acb78f9ba40ed93308583e6
Our debugger signal catcher expects to receive three args, but if
somebody cleared SA_SIGINFO we only get one, and bad things happen
when we try to use the second one. Test to see if SA_SIGINFO is
still set before we try to use the argument.
Bug: 7272866
Change-Id: If682a2262fe8a575f3802fb0c60a53eea3082456
Now we use private variables in transform-o-to-executable to support
build executables against the NDK.
Bug: 7170098
Change-Id: I6e505b33001b76f4b11fcbbb1d35392c4ddf4c70
Currently, linker doesn't update the map->l_addr for execution.
Which could break the Unwind_Backtrace with PT_GNU_EH_FRAME enabled
in new toolchain.
Change-Id: Ifbd853134da64a962f7e4c4105e56a3f20def1b2
Author: Fengwei Yin <fengwei.yin@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 57077
Lose the pid, only show the name of the function (not its whole signature),
and include the name of the library we failed to load. (I hadn't noticed
that the library name was missing before because in Java we add that into
the UnsatisfiedLinkError detail message.)
The new output looks like this:
Cannot load library: soinfo_relocate(linker.cpp:968): cannot locate symbol "__libc_malloc_default_dispatch" referenced by "libc_malloc_debug_leak.so"...
Change-Id: I3bb5c9780d9aaf3a9e4418ea55bc98122a81f80f
Per http://infocenter.arm.com/help/topic/com.arm.doc.ihi0044d/IHI0044D_aaelf.pdf
Section 4.7.1.10, ARM_R_COPY relocations are only suppose to reference shared
libraries, not the executable itself. When resolving an R_ARM_COPY symbol,
ensure we don't look in our own symbol.
This partially addresses
http://code.google.com/p/android/issues/detail?id=28598 . After this
patch, the printfs generated by the test program are:
global = 0x42 (0x401c7000)
global = 0x42 (0x11000)
before, the output was:
global = 0x42 (0x40071000)
global = 0x0 (0x11000)
I'm still not very happy with this patch, but I think it's an improvement
over where we were at before.
This change was modeled after https://android-review.googlesource.com/38871
Change-Id: Id7ad921e58395e76a36875bcc742ec5eeba53f08
This header is used on bionic build and should be propagated into
sysroot on toolchain rebuild. Discussion re. this header is here:
http://gcc.gnu.org/ml/gcc-patches/2012-08/msg00936.html
It is available already in mips NDK platforms:
development/ndk/platforms/android-9/arch-mips/include/link.h
Change-Id: I39ff467cdac9f448e31c11ee3e14a6200e82ab57
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
This patch removes the DT_NEEDED hack which stores pointers
to soinfo structs in the .dynamic section of the library
being loaded.
Instead, it caches the soinfo struct pointers on the stack
during relocation time. After relocation time, i.e. when
calling constructors and destructors of the shared library
and its dependencies, uncached access is used instead,
doing lookups using the string table entries pointed to by
the DT_NEEDED entries.
By removing this hack, it is no longer needed to undo the
PT_GNURELRO protection, i.e., all non-writable mappings
can remain non-writable during their entire lifespan.
Even though, strictly speaking, the algorithmic complexity
has increased somewhat, the real-world adverse effect
is negligible on the systems I have tested.
Change-Id: I2361502560b96b5878f7f94a8e8a215350d70d64
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@gmail.com>
This should help prevent broken builds next time I'm messing with
assembler/compiler/linker flags...
Change-Id: I30f15a3ce3c3f3c60cad7bc59aaba9f42d792224
The linker only needs to mark the text segment as
writable iff the file has text relocations. Unnecessarily
calling mprotect when it isn't necessary is slow, and some
security enhanced kernels don't like it. Pages which are
simultaneously writable and executable are considered a no-no.
The vast majority of executables / shared libraries on Android
do NOT have text relocations.
Change-Id: Ic38ce30a99b7e33ecf21efd9c108547a58eafa35
Otherwise gdb will print a spurious warning each time gdb is used:
warning: .dynamic section for "/system/bin/linker" is not at the expected
address (wrong library or version mismatch?)
BUG:6946614
Change-Id: Ib21b8db0615751189c1601140deb43bc089289b6
Remove the hand-collated ones, and switch to a script that pulls the
copyright headers out of every file and collects the unique ones.
Change-Id: Ied3b98b3f56241df97166c410ff81de4e0157c9d
Also make the errors more readable, since none of us seemed to know
what they actually meant. The new style is still as verbose as the
old, but that's probably necessary in the absence of chained exceptions
in C. Here's what you'd see if you try to boot after removing
libsurfaceflinger.so:
32267 32267 E AndroidRuntime: java.lang.UnsatisfiedLinkError: Cannot load library: (linker.c:1629, pid 32259) soinfo_link_image: could not load library "libsystem_server.so" needed by "libandroid_servers.so"; caused by (linker.c:1629, pid 32259) soinfo_link_image: could not load library "libsurfaceflinger.so" needed by "libsystem_server.so"; caused by (linker.c:709, pid 32259) load_library: library "libsurfaceflinger.so" not found
This patch also fixes almost all of the compiler warnings.
Change-Id: I64bb59aed6d4e039c15ea45be2367f319ef879f8
Given that _elf_lookup (and thus, _do_lookup) cannot possibly return an
undefined symbol (due to the check for SHN_UNDEF in _elf_lookup), there's
no need for spurious checks for SHN_UNDEF on its return value.
Conflicts:
linker/linker.c
Change-Id: Ic73cf439924b45f72d4d9ba3f64a888c96cbbd9b
GDB needs the runtime linker's base address in order to
locate the latter's ".text" and ".plt" sections, for the
purpose of detecting solib trampolines. It also can
potentially use this to calculate the relocated address
of rtld_db_dlactivity.
Bug: http://code.google.com/p/android/issues/detail?id=34856
Change-Id: I63d3e7ae4e20a684ceb25967f2241e7d58dd685d
Signed-off-by: Ryan V. Bissell <ryan@bissell.org>
Since linker is built with -fvisibility=hidden rtld_db_dlactivity()
if hidden from gdb. Unhide it otherwise gdb may not know linker
activity and rescan solib
Change-Id: Ia8cd8d9738c6ea5696ba2ef0ebf2cf783f9ca70a
Use the functions in linker_phdr.c to load the PT_LOAD segments
in memory, and toggle their mapping's writable protection bit
as needed. In particular:
- when loading a library, load the segments then unprotected
them to allow relocations to work.
- when relocating the linker of the executable, unprotect
the segments loaded by the kernel to make relocations work
too.
- after all relocations are done, re-protect the segments,
and apply GNU RELRO protection if needed.
- just before calling the destructors, undo the GNU RELRO
protection.
Change-Id: I50e709f03958204b8d6140c0f51ebe24fe089a1b
This moves the code that determines where the .dynamic and .ARM.exidx
sections are to a single place in soinfo_link_image().
Change-Id: I98adcb440577bed86442349f03f3c629c945efec
This patch changes the definition of the 'load_offset' field
in struct soinfo. The field is renamed because it is not the
basic load bias to add to every p_vaddr value read from the ELF
file to get the corresponding memory address.
This also slightly simplifies the relocation code.
+ Fix for proper load_bias computation for relocatable executables.
Change-Id: I72502c75a70751cba324deee7d313ae61f96609e
This patch changes the load_library() function in the
dynamic linker to avoid reserving a huge read-only
address-space range just to read the ELF header and
program header (which are typically very small and easily
fit in the first page).
Instead, we use the functions in linker_phdr.c to only
load the data that we need in a temporary mmap-allocated
page of memory, which we release when the function exits.
This avoids issues when loading very large libraries, or
simply debug versions that only need to load a tiny percentage
of their overall file content in RAM.
Change-Id: Id3a189fad2119a870a1b3d43dd81380c54ea6044
This patch introduces two new source files containing a set of functions
to manage the program header table in an ELF binary, including the ability
to load PT_LOAD segments, and apply PT_GNU_RELRO protection.
Note: the files are not used currently, this will appear in a series
of future patches that will gradually modify linker.c to use
the phdr_table_xxx functions properly.
Change-Id: Ia3d4c1ff5fc3e265d8258b64b492f4e643f51bdc
With -fstack-protector, x86 -m32 needs __stack_chk_fail_local
defined in crtbegin_*.o.
Include __stack_chk_fail_local.S in begin.S otherwise linker
(which is built w/o crt*) may not link.
Change-Id: Id242fcf3eff157264afe3b04f27288ab7991220a
This patch adds a trivial implementation of snprintf() that calls
our internal vsnprintf().
Inspection of the generated machine code showed that the linker
contained a full implementation of stdio's vfprintf. It was pulled
in because the pthread implementation uses snprintf() somewhere.
ProTip: It's possible to see why specific objects files are included
in a final binary by adding the following to your Android.mk, then
looking at the content of /tmp/MAP.TXT:
LOCAL_LDFLAGS += -Wl,-Map=/tmp/MAP.TXT
Change-Id: I325e71b0cad1d01116a2e00c09e30a80cb716aa3
This patch adds to make the linker a little bit easier to understand
by making all functions that acts on a sofino object with a soinfo_
prefix.
This is to more easily distinguish functions that operate on global
state, and those that operate on individual libraries.
This should be purely stylistic, i.e. no feature/behaviour change.
Change-Id: Ie510d13d743aa4317644caefa9910b8af7e84f44
Before changing mmap() permission to PROT_NONE in alloc_mem_region(),
such libraries once worked with a bug that uses mmap'ed region outside of
memory region allocated by alloc_mem_region(). This possibly incurs
SIGSEGV because it can overwrite memory region of previously loaded
library, but it sometimes worked, depending on loading order.
After PROT_NONE, this caused SIGSEGV earlier during calculation of
si->phdr in load_library(), but this was fixed by:
75917c84d1 Use mmap to read an ...
Now the behaviour is the same as before applying PROT_NONE in
alloc_mem_region().
This CL fixed the original issue, supporting shared libraries that have
non-zero p_vaddr in first (= with lowest p_vaddr) PT_LOAD segment.
Bug: 6561258
Change-Id: Ib6176dd3e44c4d99a340eb1cbd16fb037586b0bc
Also, fixes SIGSEV during calculation of si->phdr in load_library(),
which is caused by accessing PHDR area, which is not guaranteed to be
loaded.
Note that this usually does not happen because program header area is
covered by immediately following PT_LOAD entry. But it does not hold
always.
Bug: 6561258
Change-Id: Ie376253c773b5420279ca89044e81b1aad5a5736
Previously, the linker always loaded itself into the same
location in memory, which inhibited the effectiveness of Android's
ASLR implementation. Modify the linker code so it can be relocatable
and link itself at runtime.
Change-Id: Ia80273d7a00ff648b4da545f4b69debee6343968
Use LOCAL_NO_CRT to prevent linking against crtbegin.o, rather than
messing with build rules. This also prevents linking against crtend.o,
which isn't needed for the linker.
Change-Id: I0c5b9999be7e8676560fe145c1c033ffce8db4d1
The computation of si->base assumed that the first entry in the
program header table is a PT_PHDR. This results in the dynamic
linker crashing with a SIGSEGV/MAPERR when trying to load some
of the NDK unit test programs, which happen to have an EXIDX
header first, followed byu a PHDR one.
This patch fixes the computation by parsing the program header
table, looking explicitely for the PHDR entry. This fixes the
load of the NDK unit test programs, and doesn't affect system
libraries.
Change-Id: Id18ea6037dbe950b5abbbce816c2960321f0b81d
Modify the dynamic linker so that executables can be loaded
at locations other than 0x00000000.
Modify crtbegin* so that non-PIC compilant "thumb interwork
veneers" are not created by the linker.
Bug: 5323301
Change-Id: Iece0272e2b708c79034f302c20160e1fe9029588
The ARM static linker wasn't properly handling __exidx_start
and __exidx_end symbols. Now that the static linker has been fixed,
we don't need the dynamic linker to work around this problem.
Change-Id: I041b94903609fafab33663a7d441a5e70b7ffcdd
Since e19d702b8e, dlsym and friends use recursive mutexes that
require the current thread id, which is not available before the libc
constructor. This prevents us from using dlsym() in .preinit_array.
This change moves TLS initialization from libc constructor to the earliest
possible point - immediately after linker itself is relocated. As a result,
pthread_internal_t for the initial thread is available from the start.
As a bonus, values stored in TLS in .preinit_array are not lost when libc is
initialized.
Change-Id: Iee5a710ee000173bff63e924adeb4a4c600c1e2d
This reverts commit 61ff83475c.
This code is harmless, and only applies to the linker, so
there's no harm in keeping it in the tree a little bit longer.
Let's roll this back while we try to figure out the root cause
of bug 6314858.
Bug: 6314858
Change-Id: I9f5ed81d23a7abe273baf792aa8a0a2839ef094c
The ARM static linker wasn't properly handling __exidx_start
and __exidx_end symbols. Now that the static linker has been fixed,
we don't need the dynamic linker to work around this problem.
Change-Id: Ic567122b6c7746cc016795e2befba2c6bd7c0478
Compile the linker with -fvisibility=hidden. This reduces the number
of symbols that show up in the .dynsym section of the linker.
These symbols are never exported to other applications.
In particular, this fixes a problem with setting -DLINKER_DEBUG=1
introduced in 468319ce4f.
Because the symbols "debug_verbosity" and "format_log" have not been
resolved before the linker links itself, any attempt to call
PRINT / INFO / TRACE / WARN / ERROR will result in a segfault.
This change allows the static linker to produce a relative reference
to these symbols rather than relying on relocation.
This also has a nice side effect of making the linker slightly smaller
and slightly more optimized.
The following symbols no longer in the .dynsym section of the linker
after this change:
-addr_to_name
-call_constructors_recursi
-calloc
-debugger_init
-debugger_signal_handler
-debug_verbosity
-dladdr
-dlclose
-dlerror
-dl_lock
-dlopen
-dlsym
-dl_unwind_find_exidx
-find_containing_library
-find_containing_symbol
-find_library
-format_buffer
-free
-libdl_info
-linker_env_get
-linker_env_init
-linker_env_secure
-linker_env_unset
-linker_get_error
-__linker_init
-lookup
-lookup_in_library
-malloc
-notify_gdb_of_libraries
-notify_gdb_of_load
-notify_gdb_of_unload
-realloc
-rtld_db_dlactivity
-unload_library
-vsnprintf
Bug: 5827809
Change-Id: I5e8cd7dcf48c1d6831a970a67f63f24916c5e437
When the dynamic linker loads a shared library into memory, it
initially allocates a chunk of memory. The memory is then carved
into smaller chunks for each LOAD region, and appropriate memory
protections applied.
Modify the initial memory allocation so that the pages are mapped
as PROT_NONE, rather than PROT_READ / PROT_EXEC. This ensures that
gaps between LOAD regions are not inadvertantly readable / executable.
(Long term, we should munmap() these gaps entirely)
Change-Id: If128a203ccc6fe12dcbbd2bfe0cf13a2045675af
If we catch a fatal signal that won't automatically re-throw when
the thread resumes, re-throw it manually. (Common examples are
SIGPIPE and the SIGFPE from integer division by zero.)
Change-Id: I329e6d4db907047c555957b42cbd09c50fc808e7
This adds the thread id and name to the "Fatal signal" logging,
making it easier to track down where in process it actually crashed.
Change-Id: I17a365042b2f10b161debe98bc2e7070af055dfb
Add support for PT_GNU_RELRO. This allows the static linker to
indicate that certain regions of memory should be marked as
"read-only" after dynamic linking is complete.
See:
* http://www.akkadia.org/drepper/nonselsec.pdf (section 6)
* http://tk-blog.blogspot.com/2009/02/relro-not-so-well-known-memory.html
Note that this change has no effect on Android right now, because
we don't compile our code with relro enabled.
Change-Id: I6541f8775367e8558b4388f7d105b1ae6e8f046b
That is to fix the bug:
dlxxx functions can't be called recursively.
For example, if we use dlopen() to use open one library whose constructor
also calls dlopen() in order to open another library, then the thread is
dead-blocked.
By changing the dl_lock from a non-recursive lock to a recursive lock, we can
prevent the thread from dead-blocked by recursive dlxxx calls in the same
thread context.
Change-Id: I1018b41c82f4641cc009c0a2eda31f5a47a534f9
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
We don't have a toolchain anymore, we don't have working original
kernel headers, and nobody is maintaining this so there is really
no point in keeping this here. Details of the patch:
- removed code paths from Android.mk files related to the SuperH
architecture ("sh")
- removed libc/arch-sh, linker/arch-sh, libc/kernel/arch-sh
- simplified libc/SYSCALLS.TXT
- simplified the scripts in libc/tools/ and libc/kernel/tools
Change-Id: I26b0e1422bdc347489e4573e2fbec0e402f75560
Signed-off-by: David 'Digit' Turner <digit@android.com>
The flag to avoid calling ELF constructors recursively (in the case
of recursive .so dependencies) was being set after the dangerous
recursive constructor call had already been made.
This fixes the libc's debug malloc implementation.
Change-Id: I5e601f0ea19ab1df81b8b1ad4df25c3eab0ccda4
Write a message to the log file if the signal handler is not able
to connect to debuggerd. This is especially handy if the failure
was caused by running out of file descriptors, since there's some
chance that the lack of fds relates to the crash.
Sample:
F libc : Fatal signal 11 (SIGSEGV) at 0xdeadbaad (code=1)
F libc : Unable to open connection to debuggerd: Too many open files
Bug 5926330
Change-Id: I0ff210d82ab1db39b08f328bae5e08f67a69e5d7
The Linux kernel provides an AT_SECURE auxv flag to inform userspace
whether or not a security transition has occurred. This is more reliable
than directly checking the uid/gid against the euid/egid, because it covers
not only setuid/setgid but also file capabilities, SELinux, and AppArmor
security transitions. It is also a more efficient test since it does
not require any additional system calls.
Change-Id: I9752a4f6da452273258d2876d13b05e402fb0409
This change makes linker handling of .preinit_array compliant with the
System V ABI:
"These [pre-initialization] functions are executed after the dynamic linker has
built the process image and performed relocations but before any shared object
initialization functions."
http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#init_fini
Change-Id: Iebfee22bb1ebe1d7c7e69cb4686e4ebae0dfc4bb
