platform_bionic/libc/arch-common/bionic/crtbegin_so.c
Ryan Prichard bcea0e2afd Call __emutls_unregister_key on dlclose
We want to delay the emutls pthread key deletion to keep
__thread/thread_local variables working as long as possible.

Currently, emutls has its own __attribute__((destructor)) function that
deletes its pthread key. That function runs even on process exit, and it
can run before other destructor functions and before C++ static object
destructors.

Move the destructor function to crtbegin_so.c, where an
__attribute__((destructor)) function is only called on dlclose. Use a
priority 0 destructor, which runs after every destructor with a default or
greater priority value.

__emutls_unregister_key will still run before destructor functions of
DT_NEEDED solibs. It also still leaks memory (both the emutls arrays and
each emutls object).

Bug: b/80453944
Test: manual
Change-Id: I6789bcf168415ab8badf2f64687c6a0136c5c917
2018-06-19 13:22:36 -07:00

78 lines
2.9 KiB
C

/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
extern void __cxa_finalize(void *);
extern void *__dso_handle;
__attribute__((destructor))
static void __on_dlclose(void) {
__cxa_finalize(&__dso_handle);
}
/* Define a weak stub function here that will be overridden if the solib uses
* emutls. The function needs to be a definition, not just a declaration,
* because gold has a bug where it outputs weak+hidden symbols into the .dynsym
* table. */
__attribute__((weak,visibility("hidden")))
void __emutls_unregister_key(void) {
}
/* Use a priority of 0 to run after any ordinary destructor function. The
* priority setting moves the function towards the front of the .fini_array
* section. */
__attribute__((destructor(0)))
static void __on_dlclose_late(void) {
__emutls_unregister_key();
}
/* CRT_LEGACY_WORKAROUND should only be defined when building
* this file as part of the platform's C library.
*
* The C library already defines a function named 'atexit()'
* for backwards compatibility with older NDK-generated binaries.
*
* For newer ones, 'atexit' is actually embedded in the C
* runtime objects that are linked into the final ELF
* binary (shared library or executable), and will call
* __cxa_atexit() in order to un-register any atexit()
* handler when a library is unloaded.
*
* This function must be global *and* hidden. Only the
* code inside the same ELF binary should be able to access it.
*/
#ifdef CRT_LEGACY_WORKAROUND
# include "__dso_handle.h"
#else
# include "__dso_handle_so.h"
# include "atexit.h"
#endif
#include "pthread_atfork.h"
#ifdef __i386__
# include "../../arch-x86/bionic/__stack_chk_fail_local.h"
#endif