platform_bionic/libc/bionic/libc_init_static.cpp
Christopher Ferris 93ea09f65c Add directives to force stop unwinding.
On aarch64/x86/x86_64 add a macro that inserts a cfi directive that will
stop unwinding.

For arm, clang doesn't allow emitting .cantunwind, so add a comment and
leave it the same as it current is.

Add this macro to __libc_init and __start_thread.

Also, remove duplicate compilation of libc_init_static.cpp that already
includes the static library that includes that file.

Bug: 15469122

Test: Did unwinds using new unwinder tool (unwind) and debuggerd -b
Test: and verified new unwinder works on aarch64/x86/x86_64.
Test: Verified that it works on old unwinder for aarch64/x86, but
Test: x86_64 doesn't work properly, but as well as before.
Change-Id: I77302e8f6c7ba1549d98a4a164106ee82c9ecadc
2017-10-05 15:18:47 -07:00

118 lines
4.1 KiB
C++

/*
* Copyright (C) 2008 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.
*/
#include <android/api-level.h>
#include <elf.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/auxv.h>
#include <sys/mman.h>
#include "libc_init_common.h"
#include "pthread_internal.h"
#include "private/bionic_globals.h"
#include "private/bionic_macros.h"
#include "private/bionic_page.h"
#include "private/bionic_tls.h"
#include "private/KernelArgumentBlock.h"
extern "C" int __cxa_atexit(void (*)(void *), void *, void *);
static void call_array(void(**list)()) {
// First element is -1, list is null-terminated
while (*++list) {
(*list)();
}
}
static void apply_gnu_relro() {
ElfW(Phdr)* phdr_start = reinterpret_cast<ElfW(Phdr)*>(getauxval(AT_PHDR));
unsigned long int phdr_ct = getauxval(AT_PHNUM);
for (ElfW(Phdr)* phdr = phdr_start; phdr < (phdr_start + phdr_ct); phdr++) {
if (phdr->p_type != PT_GNU_RELRO) {
continue;
}
ElfW(Addr) seg_page_start = PAGE_START(phdr->p_vaddr);
ElfW(Addr) seg_page_end = PAGE_END(phdr->p_vaddr + phdr->p_memsz);
// Check return value here? What do we do if we fail?
mprotect(reinterpret_cast<void*>(seg_page_start), seg_page_end - seg_page_start, PROT_READ);
}
}
// The program startup function __libc_init() defined here is
// used for static executables only (i.e. those that don't depend
// on shared libraries). It is called from arch-$ARCH/bionic/crtbegin_static.S
// which is directly invoked by the kernel when the program is launched.
//
// The 'structors' parameter contains pointers to various initializer
// arrays that must be run before the program's 'main' routine is launched.
__noreturn void __libc_init(void* raw_args,
void (*onexit)(void) __unused,
int (*slingshot)(int, char**, char**),
structors_array_t const * const structors) {
BIONIC_STOP_UNWIND;
KernelArgumentBlock args(raw_args);
__libc_init_main_thread(args);
// Initializing the globals requires TLS to be available for errno.
__init_thread_stack_guard(__get_thread());
__libc_init_globals(args);
__libc_init_AT_SECURE(args);
__libc_init_common(args);
apply_gnu_relro();
// Several Linux ABIs don't pass the onexit pointer, and the ones that
// do never use it. Therefore, we ignore it.
call_array(structors->preinit_array);
call_array(structors->init_array);
// The executable may have its own destructors listed in its .fini_array
// so we need to ensure that these are called when the program exits
// normally.
if (structors->fini_array != NULL) {
__cxa_atexit(__libc_fini,structors->fini_array,NULL);
}
exit(slingshot(args.argc, args.argv, args.envp));
}
uint32_t bionic_get_application_target_sdk_version() {
return __ANDROID_API__;
}