rtld and libc use different storage, so the initial version would
incorrectly report the failure reason for fork().
There is still a small race condition inside ld.elf_so as it doesn't use
thread-safe errno internally, but that's a more contained internal
issue.
in a consistent state. This most importantly avoids races between dlopen
and friends and fork, potentially resulting in dead locks in the child
when it itself tries to acquire locks.
on a linker common page size boundary. However, if the common page size
used by the linker is less than the VM page size being used by the kernel,
this can end up in the middle of a VM page and when the region is write-
protected, this can cause objects in neighboring .data to get incorrectly
write-protected, resulting in a crash.
Avoid this situation by calculating the end of the RELRO region not by
rounding memsz up to the VM page size, but rather by adding vaddr + memsz
and then truncating to the VM page size.
Fixes PR toolchain/55043.
XXX pullup-9
Define Elf_Hash struct that contains ELF/SYSV and GNU hash checksum.
Implement _rtld_gnu_hash() for DT_GNU_HASH.
Adapt existing code to compute all Elf_Hash types, instead of only
the ELF/SYSV one.
Rename _rtld_elf_hash() to _rtld_sysv_hash() to match the GNU toolchain
terminology.
_rtld_gnu_hash() uses Dan Bernstein's string hash function posted eons ago
on comp.lang.c.
Early ELF binaries defined dlopen and friends in crt0.o by
using function pointers in the object handle passed from rtld.
This contract wastes space when many shared objects are allocated
and ties dynamic linker and rest of the system tightly together.
Fake the entry points in a static object and restrict them to the
platforms that had working ELF support at the time. Keep the magic and
version field used by modern crt0.o for all architectures. The checks
will be removed from crt0.o in a follow-up step.
- Move to a shared _rtld_call_ifunc for rel and rela architectures
- Architectures using rel format must patch IRELATIVE non-PLT
relocations like RELATIVE in additition to the later ifunc handling
- Consistently record the delta to the end of the relocation group for
non-PLT IRELATIVE relocations
Hidden ifunc is now supported on all ifunc platforms, even when using
-fno-plt. The combination of -fno-plt and relro is broken due to
incorrect GNU ld output though.
functions are used for destructors of thread_local objects.
If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.
Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.
This fixes the most of lockups i observed with Open vSwitch
on NetBSD/amd64. ("most of" because it still occasionally
locks up because of other problems. see PR/49816)
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.
Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions
Inspired by FreeBSD's r228435 by kib@freebsd.org.
rumpuser_dl_bootstrap, then return &_rtld_objself as the handle and do
not create a duplicate mapping.
The handle is mostly useless as _rtld_objself doesn't appear on
_rtld_objlist.
This fixes a problem on earm platforms where ld.elf_so (currently) has
an init_array section. Calling this caused binaries to segv.
- add function to add name aliases for shared libraries loaded
XXX[1]: we don't add a name during load time, only when DT_SONAME
is present.
- search already loaded objects in load_by_name for an already
loaded object that matches our name and return it.
- add missing initialization and cleanup for obj->names
XXX[2]: should we make them SIMPLEQ?
- Add XXX in rtld.c about getting the name of an object.
NB: This makes the jdk work again without resorting to a hack of putting
the build path of libjvm.so into the run path (which is a security
problem).
XXX: Pullup-6?
vector. This can normally be found via __ps_strings, but libc is
initialised too early when linked dynamically and doesn't have access to
it yet, so provide an alternative mechanism via ld.elf_so.
Bump libc minor.
