platform_bionic/libc/bionic/libc_init_dynamic.c
David 'Digit' Turner 03eabfe65e Fix the C library initialization to avoid calling static C++ constructors twice.
The problem was due to the fact that, in the case of dynamic executables,
the dynamic linker calls the DT_PREINIT_ARRAY, DT_INIT and DT_INIT_ARRAY
constructors when loading shared libraries and dynamic executables,
*before* calling the executable's entry point (i.e. arch-$ARCH/bionic/crtbegin_dynamic.c)
which in turns call __libc_init() in libc.so, as defined by bionic/libc_init_dynamic.c

The latter did call these constructors array again, mistakenly.

The patch also updates the documentation of many related functions.

Also adds a new section to linker/README.TXT explaining restrictions on
C library usage.

The patch has been tested on a Dream for stability issues with
proprietary blobs:

- H264 decoding works
- Camera + Video recording works
- GPS works
- Sensors work

The tests in system/extra/tests/bionic/libc/common/test_static_cpp_mutex.cpp has been
run and shows the static C++ constructor being called only once.
2009-06-02 23:27:44 +02:00

90 lines
3.4 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_static.c
*
* This function is called for dynamic executables after the dynamic
* linker has loaded and initialized all dependent shared libraries.
*
* It takes the raw data block set up by the ELF loader
* in the kernel and parses it.
*
* The arguments are:
* elfdata -- The ELF loader data block; usually from the stack.
* Basically a pointer to argc.
*
* onexit -- Function to call on exit, can be NULL.
*
* slingshot -- Address of the program's main function
*
* structors -- Table of constructor functions arrays that must
* be called before the slingshot.
*
* It is called from the assembly fragment found in
* arch-$ARCH/bionic/crtbegin_dynamic.S
*/
/*
* Several Linux ABIs don't pass the onexit pointer, and the ones that
* do never use it. Therefore, unless USE_ONEXIT is defined, we just
* ignore the onexit pointer.
*/
/* #define USE_ONEXIT */
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <elf.h>
#include "pthread_internal.h"
#include "atexit.h"
#include "libc_init_common.h"
extern void malloc_debug_init();
__noreturn void __libc_init(uintptr_t *elfdata,
void (*onexit)(void),
int (*slingshot)(int, char**, char**),
structors_array_t const * const structors)
{
/* NOTE: At this point, the dynamic linker has *already* called
* all initializers properly, so we ignore 'structors' to
* avoid calling them twice.
*/
/* NOTE2: Is it worthwhile to use malloc_debug_init() in the case of
* of the non-debug shared C library ?
*
* The implementation in bionic/malloc_leak.c contains a lot
* of code which will turn to be unused, and we add a dispatch
* overhead to malloc() et al. that proved to be significant
* in the past (e.g. making boot sequence 5% slower)
*/
__libc_init_common(elfdata, onexit, slingshot, NULL, malloc_debug_init);
}