bionic/libc/private/bionic_preinit.h
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

77 lines
2.9 KiB
C

/*
* Copyright (C) 2009 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.
*/
#ifndef _BIONIC_PREINIT_H
#define _BIONIC_PREINIT_H
#include "pthread_internal.h"
#include "bionic_tls.h"
#include <asm/page.h>
/* this function is used to perform a minimal initialization of the
* the C library. This must be performed before any other call to
* other functions, in either the dynamic linker's startup code
* or libc_init_static.c
*
* 'main_thread' and 'tls_area' must be persistent variables,
* which means they must be either global, or allocated in the
* main thread's stack frame and never, ever, freed before
* program exit.
*
* VERY IMPORTANT NOTE:
*
* THIS IMPLEMENTATION SHOULD NOT USE GLOBAL VARIABLES.
*
* The reason is the dynamic linker's tricky usage of C library
* functions and later renaming of their symbols. See the
* "C Library Usage Restriction" section in bionic/linker/README.TXT
* for details.
*/
extern unsigned __get_sp(void);
extern pid_t gettid(void);
static __inline__ void
__libc_preinit( pthread_internal_t* main_thread,
void* tls_area[BIONIC_TLS_SLOTS] )
{
pthread_attr_t thread_attr;
/* Setup the main thread's information */
unsigned stacktop = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE;
unsigned stacksize = 128 * 1024;
unsigned stackbottom = stacktop - stacksize;
pthread_attr_init(&thread_attr);
pthread_attr_setstack(&thread_attr, (void*)stackbottom, stacksize);
_init_thread(main_thread, gettid(), &thread_attr, (void*)stackbottom);
__init_tls(tls_area, main_thread);
}
#endif /* _BIONIC_INIT_H */