60 lines
2.4 KiB
C++
60 lines
2.4 KiB
C++
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/*
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* Copyright (C) 2017 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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#include "private/KernelArgumentBlock.h"
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extern const char linker_code_start;
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extern const char original_start;
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extern const char linker_entry;
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/*
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* This is the entry point for the linker wrapper, which finds
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* the real linker, then bootstraps into it.
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*/
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extern "C" ElfW(Addr) __linker_init(void* raw_args) {
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KernelArgumentBlock args(raw_args);
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static uintptr_t linker_offset = reinterpret_cast<uintptr_t>(&linker_code_start);
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static uintptr_t linktime_addr = reinterpret_cast<uintptr_t>(&linktime_addr);
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ElfW(Addr) my_addr = reinterpret_cast<uintptr_t>(&linktime_addr) - linktime_addr;
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// Set AT_ENTRY to the proper entry point
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for (ElfW(auxv_t)* v = args.auxv; v->a_type != AT_NULL; ++v) {
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if (v->a_type == AT_BASE) {
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v->a_un.a_val = my_addr + linker_offset;
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}
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if (v->a_type == AT_ENTRY) {
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v->a_un.a_val = my_addr + reinterpret_cast<uintptr_t>(&original_start);
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}
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}
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// Return address of linker entry point -- may need to ensure that raw_args
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// was saved.
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return my_addr + linker_offset + reinterpret_cast<uintptr_t>(&linker_entry);
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}
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