309 lines
9.7 KiB
C
309 lines
9.7 KiB
C
/**
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* \addtogroup loader
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* @{
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*/
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/**
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* \defgroup elfloader The Contiki ELF loader
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*
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* The Contiki ELF loader links, relocates, and loads ELF
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* (Executable Linkable Format) object files into a running Contiki
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* system.
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*
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* ELF is a standard format for relocatable object code and executable
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* files. ELF is the standard program format for Linux, Solaris, and
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* other operating systems.
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*
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* An ELF file contains either a standalone executable program or a
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* program module. The file contains both the program code, the
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* program data, as well as information about how to link, relocate,
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* and load the program into a running system.
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*
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* The ELF file is composed of a set of sections. The sections contain
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* program code, data, or relocation information, but can also contain
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* debugging information.
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*
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* To link and relocate an ELF file, the Contiki ELF loader first
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* parses the ELF file structure to find the appropriate ELF
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* sections. It then allocates memory for the program code and data in
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* ROM and RAM, respectively. After allocating memory, the Contiki ELF
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* loader starts relocating the code found in the ELF file.
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*
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* @{
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*/
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/**
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* \file
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* Header file for the Contiki ELF loader.
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* \author
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* Adam Dunkels <adam@sics.se>
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* Simon Berg <ksb@users.sourceforge.net>
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*
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*/
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/*
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* Copyright (c) 2005, Swedish Institute of Computer Science
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* Copyright (c) 2007, Simon Berg
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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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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT 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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* This file is part of the Contiki operating system.
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*
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*/
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#ifndef ELFLOADER_H_
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#define ELFLOADER_H_
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#include "cfs/cfs.h"
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/**
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* Return value from elfloader_load() indicating that loading worked.
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*/
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#define ELFLOADER_OK 0
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/**
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* Return value from elfloader_load() indicating that the ELF file had
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* a bad header.
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*/
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#define ELFLOADER_BAD_ELF_HEADER 1
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/**
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* Return value from elfloader_load() indicating that no symbol table
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* could be find in the ELF file.
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*/
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#define ELFLOADER_NO_SYMTAB 2
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/**
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* Return value from elfloader_load() indicating that no string table
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* could be find in the ELF file.
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*/
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#define ELFLOADER_NO_STRTAB 3
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/**
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* Return value from elfloader_load() indicating that the size of the
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* .text segment was zero.
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*/
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#define ELFLOADER_NO_TEXT 4
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/**
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* Return value from elfloader_load() indicating that a symbol
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* specific symbol could not be found.
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*
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* If this value is returned from elfloader_load(), the symbol has
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* been copied into the elfloader_unknown[] array.
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*/
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#define ELFLOADER_SYMBOL_NOT_FOUND 5
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/**
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* Return value from elfloader_load() indicating that one of the
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* required segments (.data, .bss, or .text) could not be found.
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*/
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#define ELFLOADER_SEGMENT_NOT_FOUND 6
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/**
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* Return value from elfloader_load() indicating that no starting
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* point could be found in the loaded module.
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*/
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#define ELFLOADER_NO_STARTPOINT 7
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/**
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* Return value from elfloader_load() indicating that the ELF file contained
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* a relocation type that the implementation can't handle.
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*/
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#define ELFLOADER_UNHANDLED_RELOC 8
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/**
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* Return value from elfloader_load() indicating that the offset for
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* a relative addressing mode was too big.
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*/
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#define ELFLOADER_OUTOF_RANGE 9
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/**
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* Return value from elfloader_load() indicating that the relocations
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* where not sorted by offset
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*/
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#define ELFLOADER_RELOC_NOT_SORTED 10
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/**
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* Return value from elfloader_load() indicating that reading from the
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* ELF file failed in some way.
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*/
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#define ELFLOADER_INPUT_ERROR 11
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/**
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* Return value from elfloader_load() indicating that writing to a segment
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* failed.
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*/
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#define ELFLOADER_OUTPUT_ERROR 12
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#define ELFLOADER_SEG_TEXT 1
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#define ELFLOADER_SEG_RODATA 2
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#define ELFLOADER_SEG_DATA 3
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#define ELFLOADER_SEG_BSS 4
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/**
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* elfloader output object
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*
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* This object defines methods (callbacks) for writing the segments to memory.
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* It can be extended by the user to include any necessary state.
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*/
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struct elfloader_output {
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const struct elfloader_output_ops *ops;
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};
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/**
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* \brief Allocate a new segment
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* \param output The output object
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* \param type Type of segment
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* \param size Size of segment in bytes
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* \return A pointer to the start of the segment.
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*
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* The returned address doesn't need to correspond to any real memory,
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* since it's only used for calculating the relocations.
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*/
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void *elfloader_allocate_segment(struct elfloader_output *output,
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unsigned int type, int size);
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/**
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* \brief Start writing to a new segment
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* \param output The output object
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* \param type Type of segment
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* \param addr Address of segment from elfloader_allocate_segment
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* \param size Size of segment in bytes
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* \return Returns ELFLOADER_OK if successful, otherwise an error code
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*
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*/
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int elfloader_start_segment(struct elfloader_output *output,
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unsigned int type, void *addr, int size);
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/**
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* \brief Mark end of segment
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* \param output The output object
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* \return Zero if successful
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*/
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int elfloader_end_segment(struct elfloader_output *output);
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/**
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* \brief Write data to a segment
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* \param output The output object
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* \param buf Data to be written
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* \param len Length of data
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* \return The number of bytes actually written, or negative if failed.
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*/
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int elfloader_write_segment(struct elfloader_output *output, const char *buf,
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unsigned int len);
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/**
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* \brief Get the current offset in the file where the next data will
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* be written.
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* \param output The output object
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* \return The current offset.
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*/
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unsigned int elfloader_segment_offset(struct elfloader_output *output);
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#define elfloader_output_alloc_segment(output, type, size) \
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((output)->ops->allocate_segment(output, type, size))
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#define elfloader_output_start_segment(output, type, addr, size) \
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((output)->ops->start_segment(output, type, addr, size))
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#define elfloader_output_end_segment(output) \
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((output)->ops->end_segment(output))
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#define elfloader_output_write_segment(output, buf, len) \
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((output)->ops->write_segment(output, buf, len))
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#define elfloader_output_segment_offset(output) \
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((output)->ops->segment_offset(output))
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struct elfloader_output_ops {
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void * (*allocate_segment)(struct elfloader_output *output,
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unsigned int type, int size);
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int (*start_segment)(struct elfloader_output *output,
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unsigned int type, void *addr, int size);
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int (*end_segment)(struct elfloader_output *output);
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int (*write_segment)(struct elfloader_output *output, const char *buf,
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unsigned int len);
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unsigned int (*segment_offset)(struct elfloader_output *output);
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};
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/**
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* elfloader initialization function.
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*
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* This function should be called at boot up to initilize the elfloader.
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*/
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void elfloader_init(void);
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/**
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* \brief Load and relocate an ELF file.
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* \param input_fd Input object defining how to read from the ELF file
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* \param output Output object defining how to create and write to seegments.
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* \return ELFLOADER_OK if loading and relocation worked.
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* Otherwise an error value.
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*
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* If the function is able to load the ELF file, a pointer
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* to the process structure in the model is stored in the
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* elfloader_loaded_process variable.
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*
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*/
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int elfloader_load(int input_fd, struct elfloader_output *output);
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/**
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* A pointer to the processes loaded with elfloader_load().
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*/
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extern struct process **elfloader_autostart_processes;
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/**
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* If elfloader_load() could not find a specific symbol, it is copied
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* into this array.
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*/
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extern char elfloader_unknown[30];
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#ifdef ELFLOADER_CONF_DATAMEMORY_SIZE
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#define ELFLOADER_DATAMEMORY_SIZE ELFLOADER_CONF_DATAMEMORY_SIZE
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#else
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#define ELFLOADER_DATAMEMORY_SIZE 0x100
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#endif
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#ifdef ELFLOADER_CONF_TEXTMEMORY_SIZE
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#define ELFLOADER_TEXTMEMORY_SIZE ELFLOADER_CONF_TEXTMEMORY_SIZE
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#else
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#define ELFLOADER_TEXTMEMORY_SIZE 0x100
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#endif
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typedef unsigned long elf32_word;
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typedef signed long elf32_sword;
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typedef unsigned short elf32_half;
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typedef unsigned long elf32_off;
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typedef unsigned long elf32_addr;
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struct elf32_rela {
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elf32_addr r_offset; /* Location to be relocated. */
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elf32_word r_info; /* Relocation type and symbol index. */
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elf32_sword r_addend; /* Addend. */
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};
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#endif /* ELFLOADER_H_ */
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/** @} */
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/** @} */
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