07f1ded139
This hasn't built in over one release cycle and no one even noticed. art does this the right way and other projects should do the same. Change-Id: I7d1fb84c4080e008f329ee73e209ce85a36e6d55
115 lines
4.4 KiB
C++
115 lines
4.4 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.
|
|
*/
|
|
/*
|
|
* libc_init_dynamic.c
|
|
*
|
|
* This source files provides two important functions for dynamic
|
|
* executables:
|
|
*
|
|
* - a C runtime initializer (__libc_preinit), which is called by
|
|
* the dynamic linker when libc.so is loaded. This happens before
|
|
* any other initializer (e.g. static C++ constructors in other
|
|
* shared libraries the program depends on).
|
|
*
|
|
* - a program launch function (__libc_init), which is called after
|
|
* all dynamic linking has been performed. Technically, it is called
|
|
* from arch-$ARCH/bionic/crtbegin_dynamic.S which is itself called
|
|
* by the dynamic linker after all libraries have been loaded and
|
|
* initialized.
|
|
*/
|
|
|
|
#include <stddef.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <stdint.h>
|
|
#include <elf.h>
|
|
#include "atexit.h"
|
|
#include "libc_init_common.h"
|
|
|
|
#include "private/bionic_tls.h"
|
|
#include "private/KernelArgumentBlock.h"
|
|
|
|
extern "C" {
|
|
extern void malloc_debug_init(void);
|
|
extern void malloc_debug_fini(void);
|
|
extern void netdClientInit(void);
|
|
};
|
|
|
|
// We flag the __libc_preinit function as a constructor to ensure
|
|
// that its address is listed in libc.so's .init_array section.
|
|
// This ensures that the function is called by the dynamic linker
|
|
// as soon as the shared library is loaded.
|
|
__attribute__((constructor)) static void __libc_preinit() {
|
|
// Read the kernel argument block pointer from TLS.
|
|
void** tls = __get_tls();
|
|
KernelArgumentBlock** args_slot = &reinterpret_cast<KernelArgumentBlock**>(tls)[TLS_SLOT_BIONIC_PREINIT];
|
|
KernelArgumentBlock* args = *args_slot;
|
|
|
|
// Clear the slot so no other initializer sees its value.
|
|
// __libc_init_common() will change the TLS area so the old one won't be accessible anyway.
|
|
*args_slot = NULL;
|
|
|
|
__libc_init_common(*args);
|
|
|
|
// Hooks for various libraries to let them know that we're starting up.
|
|
malloc_debug_init();
|
|
netdClientInit();
|
|
}
|
|
|
|
__LIBC_HIDDEN__ void __libc_postfini() {
|
|
// A hook for the debug malloc library to let it know that we're shutting down.
|
|
malloc_debug_fini();
|
|
}
|
|
|
|
// This function is called from the executable's _start entry point
|
|
// (see arch-$ARCH/bionic/crtbegin_dynamic.S), which is itself
|
|
// called by the dynamic linker after it has loaded all shared
|
|
// libraries the executable depends on.
|
|
//
|
|
// Note that the dynamic linker has also run all constructors in the
|
|
// executable at this point.
|
|
__noreturn void __libc_init(void* raw_args,
|
|
void (*onexit)(void),
|
|
int (*slingshot)(int, char**, char**),
|
|
structors_array_t const * const structors) {
|
|
|
|
KernelArgumentBlock args(raw_args);
|
|
|
|
// Several Linux ABIs don't pass the onexit pointer, and the ones that
|
|
// do never use it. Therefore, we ignore it.
|
|
|
|
// 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) {
|
|
__cxa_atexit(__libc_fini,structors->fini_array,NULL);
|
|
}
|
|
|
|
exit(slingshot(args.argc, args.argv, args.envp));
|
|
}
|