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/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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/* Based on the code from GNU libc, but hacked up by John Beppu and Erik Andersen */
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/* adapted by PaX Team for ET_DYN/PIE binaries */
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/*
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When we enter this piece of code, the program stack looks like this:
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argc argument counter (integer)
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argv[0] program name (pointer)
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argv[1...N] program args (pointers)
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argv[argc-1] end of args (integer)
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NULL
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env[0...N] environment variables (pointers)
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NULL
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*/
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#include
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.text
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.align 4
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.global _start
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.type _start,%function
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#if defined L_crt0 || defined L_Scrt0 || ! defined __UCLIBC_CTOR_DTOR__
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.type __uClibc_main,%function
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#else
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.weak _init
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.weak _fini
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.type __uClibc_start_main,%function
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#endif
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/* Stick in a dummy reference to main(), so that if an application
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* is linking when the main() function is in a static library (.a)
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* we can be sure that main() actually gets linked in */
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.type main,%function
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_start:
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/* locate the start of the environment variables */
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popl %ecx /* Store argc into %ecx */
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movl %esp,%ebx /* Store argv into ebx */
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movl %esp,%eax /* Store argv into eax as well*/
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movl %ecx,%edx /* Stick argc into %edx so we can do some math in a sec */
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leal 4(%eax,%edx,4),%eax
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/* [ register layout ]
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sizeof(char*) == 4
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%ecx = argc ; 0(esp)
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%ebx = argv ; 4(esp)
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%eax = env ; argv + (argc * 4) + 4
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*/
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/* Set up an invalid (NULL return address, NULL frame pointer)
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callers stack frame so anybody unrolling the stack knows where
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to stop */
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xorl %ebp,%ebp /* NULL */
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pushl %ebp /* callers %cs */
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pushl %ebp /* callers %eip (return address) */
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pushl %ebp /* callers %ebp (frame pointer) */
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movl %esp,%ebp /* mark callers stack frame as invalid */
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#if defined L_Scrt0 || defined L_Scrt1
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call .L0
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.L0:
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pop %edx
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addl $_GLOBAL_OFFSET_TABLE_+[.-.L0],%edx
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#endif
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#if (defined L_crt1 || defined L_Scrt1 || defined L_gcrt1 ) && defined __UCLIBC_CTOR_DTOR__
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/* Push .init and .fini arguments to __uClibc_start_main() on the stack */
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#ifdef L_Scrt1
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pushl _fini@GOT(%edx)
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pushl _init@GOT(%edx)
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#else
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pushl $_fini
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pushl $_init
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#endif
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/* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */
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pushl %eax /* Environment pointer */
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pushl %ebx /* Argument pointer */
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pushl %ecx /* And the argument count */
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/* Ok, now run uClibc's main() -- shouldn't return */
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#ifdef L_Scrt1
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call *__uClibc_start_main@GOT(%edx)
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#else
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call __uClibc_start_main
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#endif
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#else
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/* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */
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pushl %eax /* Environment pointer */
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pushl %ebx /* Argument pointer */
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pushl %ecx /* And the argument count */
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#ifdef L_Scrt0
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call *__uClibc_main@GOT(%edx)
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#else
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call __uClibc_main
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#endif
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#endif
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/* Crash if somehow `exit' returns anyways. */
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hlt
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.size _start,.-_start
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#if defined L_gcrt1 && defined __UCLIBC_PROFILING__
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# include "./gmon-start.S"
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#endif
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