103 lines
3.8 KiB
C
103 lines
3.8 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* libc_init_dynamic.c
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*
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* This source files provides two important functions for dynamic
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* executables:
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*
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* - a C runtime initializer (__libc_preinit), which is called by
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* the dynamic linker when libc.so is loaded. This happens before
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* any other initializer (e.g. static C++ constructors in other
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* shared libraries the program depends on).
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*
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* - a program launch function (__libc_init), which is called after
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* all dynamic linking has been performed. Technically, it is called
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* from arch-$ARCH/bionic/crtbegin_dynamic.S which is itself called
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* by the dynamic linker after all libraries have been loaded and
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* initialized.
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*/
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <elf.h>
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#include "atexit.h"
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#include "libc_init_common.h"
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#include <bionic_tls.h>
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/* We flag the __libc_preinit function as a constructor to ensure
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* that its address is listed in libc.so's .init_array section.
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* This ensures that the function is called by the dynamic linker
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* as soon as the shared library is loaded.
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*/
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void __attribute__((constructor)) __libc_prenit(void);
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void __libc_prenit(void)
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{
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/* Read the ELF data pointer from a special slot of the
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* TLS area, then call __libc_init_common with it.
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*
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* Note that:
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* - we clear the slot so no other initializer sees its value.
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* - __libc_init_common() will change the TLS area so the old one
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* won't be accessible anyway.
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*/
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void** tls_area = (void**)__get_tls();
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unsigned* elfdata = tls_area[TLS_SLOT_BIONIC_PREINIT];
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tls_area[TLS_SLOT_BIONIC_PREINIT] = NULL;
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__libc_init_common(elfdata);
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/* Setup malloc routines accordingly to the environment.
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* Requires system properties
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*/
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extern void malloc_debug_init(void);
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malloc_debug_init();
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}
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__noreturn void __libc_init(uintptr_t *elfdata,
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void (*onexit)(void),
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int (*slingshot)(int, char**, char**),
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structors_array_t const * const structors)
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{
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/* When we reach this point, all initializers have been already
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* run by the dynamic linker, so ignore 'structors'.
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*/
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int argc = (int)*elfdata;
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char** argv = (char**)(elfdata + 1);
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char** envp = argv + argc + 1;
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/* Several Linux ABIs don't pass the onexit pointer, and the ones that
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* do never use it. Therefore, we ignore it.
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*/
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exit(slingshot(argc, argv, envp));
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}
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