42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
/*
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* Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* This software is provided 'as is' and without any warranty, express or
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* implied. In no event shall the authors be liable for any damages arising
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* from the use of this software.
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*/
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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/* We need to make sure that the C compiler doesn't push any
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* additional data to the stack frame. Otherwise, assumptions
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* made by the architecture-specific implementation of the
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* FETCH_LINKPTR() macro about the location of the linkptr,
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* relative to the stack pointer, will not hold.
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*
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* Hence, we compile this function with -fomit-frame-pointer
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* and use the register storage-class specifier for all local
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* vars. Note that the latter is just a "suggestion" (see C99).
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*/
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__attribute__ ((visibility ("hidden")))
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__attribute__ ((optimize ("omit-frame-pointer")))
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void
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libucontext_trampoline(void)
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{
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register libucontext_ucontext_t *uc_link = NULL;
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FETCH_LINKPTR(uc_link);
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if (uc_link == NULL)
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exit(0);
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libucontext_setcontext(uc_link);
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}
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