134 lines
4.3 KiB
C
134 lines
4.3 KiB
C
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/*
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* Copyright (C) 2014 Google, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program 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
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* GNU General Public License for more details.
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*/
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#ifndef ELFPARSING_H
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#define ELFPARSING_H
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#include "elf.h"
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#include "common.h"
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struct parsed_elf {
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Elf64_Ehdr ehdr;
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Elf64_Phdr *phdr;
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Elf64_Shdr *shdr;
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/*
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* The relocs array contains pointers to arrays of relocation
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* structures. Each index into the relocs array corresponds to its
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* corresponding section index. i.e. if a section i is of type SHT_REL
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* or SHT_RELA then the corresponding index into the relocs array will
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* contain the associated relocations. Otherwise thee entry will be
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* NULL.
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*/
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Elf64_Rela **relocs;
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/*
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* Similarly to the relocs array the strtabs array consists of an
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* array of pointers where each entry represents a potential struct
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* buffer pointer. Only setions of type SHT_STRTAB will have a non-NULL
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* entry.
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*/
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struct buffer **strtabs;
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/* Parsed symbols. */
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Elf64_Sym *syms;
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};
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#define ELF_PARSE_PHDR (1 << 0)
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#define ELF_PARSE_SHDR (1 << 1)
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#define ELF_PARSE_RELOC (1 << 2)
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#define ELF_PARSE_STRTAB (1 << 3)
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#define ELF_PARSE_SYMTAB (1 << 4)
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#define ELF_PARSE_ALL (-1)
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/*
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* Parse an ELF file contained within provide struct buffer. The ELF header
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* is always parsed while the flags value containing the ELF_PARSE_* values
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* determine if other parts of the ELF file will be parsed as well.
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* Returns 0 on success, < 0 error.
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*/
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int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags);
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/*
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* Clean up memory associated with parsed_elf.
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*/
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void parsed_elf_destroy(struct parsed_elf *pelf);
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int
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elf_headers(const struct buffer *pinput,
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Elf64_Ehdr *ehdr,
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Elf64_Phdr **pphdr,
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Elf64_Shdr **pshdr);
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/* ELF writing support. */
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struct elf_writer;
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/*
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* Initialize a 64-bit ELF header provided the inputs. While the structure
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* is a 64-bit header one can specify a 32-bit machine. The 64-bit version
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* is just used as a common structure. If one wants to specify the entry
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* point, for example, the caller can set it after filling in the common
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* bits. The machine, nbits, and endian values should be from the ELF
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* definitions (e.g. EM_386, ELFCLASS32, and ELFDATA2LSB) found in elf.h
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* with no endian conversion required.
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*/
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void elf_init_eheader(Elf64_Ehdr *ehdr, int machine, int nbits, int endian);
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/*
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* Initialize a new ELF writer. Default machine type, endianness, etc is
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* copied from the passed in Elf64_Ehdr. Returns NULL on failure, valid
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* pointer on success.
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*/
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struct elf_writer *elf_writer_init(const Elf64_Ehdr *ehdr);
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/*
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* Clean up any internal state represented by ew. Aftewards the elf_writer
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* is invalid.
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* It is safe to call elf_writer_destroy with ew as NULL. It returns without
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* performing any action.
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*/
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void elf_writer_destroy(struct elf_writer *ew);
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/*
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* Add a section to the ELF file. Section type, flags, and memsize are
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* maintained from the passed in Elf64_Shdr. The buffer represents the
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* content of the section while the name is the name of section itself.
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* Returns < 0 on error, 0 on success.
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*/
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int elf_writer_add_section(struct elf_writer *ew, const Elf64_Shdr *shdr,
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struct buffer *contents, const char *name);
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/* Add an absolute symbol to the ELF file returning < 0 on error, index of
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* symbol otherwise. */
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int elf_writer_add_symbol(struct elf_writer *ew, const char *name,
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const char *section_name,
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Elf64_Addr value, Elf64_Word size,
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int binding, int type);
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/* Add an absolute relocation referencing the provided symbol name. Returns < 0
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* on error, 0 on success. */
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int elf_writer_add_rel(struct elf_writer *ew, const char *sym, Elf64_Addr addr);
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/*
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* Serialize the ELF file to the output buffer. Return < 0 on error,
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* 0 on success.
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*/
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int elf_writer_serialize(struct elf_writer *ew, struct buffer *out);
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/*
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* Calculate the loadable program's file size footprint. Returns < 0 on error,
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* 0 on success.
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*/
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int elf_program_file_size(const struct buffer *input, size_t *file_size);
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#endif /* ELFPARSING_H */
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