Resolves: #15465
The program name may be unavailable if the user application tampers
with argc and argv[]. Some parts of the dynamic linker caters for
this while others don't, so this patch consolidates the check and
fallback into a single macro and updates all users.
Commit glibc-2.14~10 disallowed rtld self loading to avoid a segfault
that used to happen when rtld was loading itself in normal mode.
Unfortunately, that commit disallowed all modes of self loading,
including those that used to work before. This change limits the check
for self loading to normal mode only, so that instruments like ldd could
handle rtld properly.
[BZ #13579] Do not free l_initfini and allow it to be reused
on subsequent dl_open calls for the same library. This fixes
the invalid memory access in do_lookup_x when the previously
free'd l_initfini was accessed through l_searchlist when a
library had been opened for the second time.
It may sometimes be desirable to make the dynamic linker only pick up
libraries from the library path and rpath and not look at the
ld.so.cache that ldconfig generates. An example of such a use case is
the glibc testsuite where the dynamic linker must not be influenced by
any external paths or caches.
This change adds a new option --inhibit-ldcache that when used, tells
the dynamic linker to not use ld.so.cache even if it is available.
* elf/rtld.c (dl_main): If DL_DEBUG_UNUSED is enabled, turn off
lazy binding.
* elf/dl-lookup (_dl_lookup_symbol_x): If DL_DEBUG_UNUSED, ignore
undefined symbol errors.
* elf/rtlc.c (dl_main): Skip VDSO when checking for unused
DT_NEEDED entries.
If a binary gets invoked by passing it as argument to ld.so the stack
still holds the auxiliary vector of ld.so when entering the _start
routine of the executable. So the invocation via ld.so is not fully
transparent to the executable. This causes problems if the executable
wants to scan the auxv itself.
Some symbols have to be identified process-wide by their name. This is
particularly important for some C++ features (e.g., class local static data
and static variables in inline functions). This cannot completely be
implemented with ELF functionality so far. The STB_GNU_UNIQUE binding
helps by ensuring the dynamic linker will always use the same definition for
all symbols with the same name and this binding.
* elf/dl-load.c (_dl_map_object_from_fd): Only call audit hooks
if we are not loading a new audit library.
* elf/dl-reloc (_dl_relocate_object): Third parameter is now a bitmask.
Only use profiling trampoline for auditing if we are not relocating
an audit library.
* elf/dl-open.c (dl_open_worker): Adjust _dl_relocate_object call.
* elf/rtld.c: Likewise.
* sysdeps/generic/ldsodefs.h: Adjust _dl_relocate_object prototype.
change related to AT_EXECFN. We cannot use that string.
* sysdeps/generic/ldsodefs.h (struct rtld_global_ro): Remove
_dl_execfn member.
* elf/dl-support.c: Remove _dl_execfn variable.
(_dl_aux_init): Remove handling of AT_EXECFN.
* elf/dl-sysdep.c (_dl_sysdep_start): Remove handling of AT_EXECFN.
* elf/rtld.c (process_envvars): Remove use of __ASSUME_AT_EXECFN.
