forked from KolibriOS/kolibrios
974 lines
29 KiB
C
974 lines
29 KiB
C
/* simple-object-elf.c -- routines to manipulate ELF object files.
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Copyright 2010 Free Software Foundation, Inc.
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Written by Ian Lance Taylor, Google.
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any
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later version.
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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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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, 51 Franklin Street - Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "config.h"
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#include "libiberty.h"
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#include "simple-object.h"
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#include <errno.h>
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#include <stddef.h>
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifdef HAVE_STDINT_H
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#include <stdint.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#ifdef HAVE_INTTYPES_H
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#include <inttypes.h>
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#endif
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#include "simple-object-common.h"
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/* ELF structures and constants. */
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/* 32-bit ELF file header. */
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typedef struct {
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unsigned char e_ident[16]; /* ELF "magic number" */
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unsigned char e_type[2]; /* Identifies object file type */
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unsigned char e_machine[2]; /* Specifies required architecture */
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unsigned char e_version[4]; /* Identifies object file version */
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unsigned char e_entry[4]; /* Entry point virtual address */
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unsigned char e_phoff[4]; /* Program header table file offset */
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unsigned char e_shoff[4]; /* Section header table file offset */
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unsigned char e_flags[4]; /* Processor-specific flags */
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unsigned char e_ehsize[2]; /* ELF header size in bytes */
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unsigned char e_phentsize[2]; /* Program header table entry size */
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unsigned char e_phnum[2]; /* Program header table entry count */
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unsigned char e_shentsize[2]; /* Section header table entry size */
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unsigned char e_shnum[2]; /* Section header table entry count */
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unsigned char e_shstrndx[2]; /* Section header string table index */
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} Elf32_External_Ehdr;
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/* 64-bit ELF file header. */
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typedef struct {
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unsigned char e_ident[16]; /* ELF "magic number" */
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unsigned char e_type[2]; /* Identifies object file type */
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unsigned char e_machine[2]; /* Specifies required architecture */
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unsigned char e_version[4]; /* Identifies object file version */
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unsigned char e_entry[8]; /* Entry point virtual address */
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unsigned char e_phoff[8]; /* Program header table file offset */
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unsigned char e_shoff[8]; /* Section header table file offset */
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unsigned char e_flags[4]; /* Processor-specific flags */
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unsigned char e_ehsize[2]; /* ELF header size in bytes */
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unsigned char e_phentsize[2]; /* Program header table entry size */
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unsigned char e_phnum[2]; /* Program header table entry count */
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unsigned char e_shentsize[2]; /* Section header table entry size */
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unsigned char e_shnum[2]; /* Section header table entry count */
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unsigned char e_shstrndx[2]; /* Section header string table index */
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} Elf64_External_Ehdr;
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/* Indexes and values in e_ident field of Ehdr. */
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#define EI_MAG0 0 /* File identification byte 0 index */
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#define ELFMAG0 0x7F /* Magic number byte 0 */
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#define EI_MAG1 1 /* File identification byte 1 index */
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#define ELFMAG1 'E' /* Magic number byte 1 */
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#define EI_MAG2 2 /* File identification byte 2 index */
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#define ELFMAG2 'L' /* Magic number byte 2 */
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#define EI_MAG3 3 /* File identification byte 3 index */
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#define ELFMAG3 'F' /* Magic number byte 3 */
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#define EI_CLASS 4 /* File class */
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#define ELFCLASSNONE 0 /* Invalid class */
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#define ELFCLASS32 1 /* 32-bit objects */
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#define ELFCLASS64 2 /* 64-bit objects */
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#define EI_DATA 5 /* Data encoding */
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#define ELFDATANONE 0 /* Invalid data encoding */
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#define ELFDATA2LSB 1 /* 2's complement, little endian */
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#define ELFDATA2MSB 2 /* 2's complement, big endian */
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#define EI_VERSION 6 /* File version */
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#define EV_CURRENT 1 /* Current version */
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#define EI_OSABI 7 /* Operating System/ABI indication */
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/* Values for e_type field of Ehdr. */
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#define ET_REL 1 /* Relocatable file */
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/* Values for e_machine field of Ehdr. */
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#define EM_SPARC 2 /* SUN SPARC */
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#define EM_SPARC32PLUS 18 /* Sun's "v8plus" */
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/* Special section index values. */
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#define SHN_LORESERVE 0xFF00 /* Begin range of reserved indices */
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#define SHN_XINDEX 0xFFFF /* Section index is held elsewhere */
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/* 32-bit ELF program header. */
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typedef struct {
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unsigned char p_type[4]; /* Identifies program segment type */
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unsigned char p_offset[4]; /* Segment file offset */
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unsigned char p_vaddr[4]; /* Segment virtual address */
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unsigned char p_paddr[4]; /* Segment physical address */
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unsigned char p_filesz[4]; /* Segment size in file */
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unsigned char p_memsz[4]; /* Segment size in memory */
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unsigned char p_flags[4]; /* Segment flags */
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unsigned char p_align[4]; /* Segment alignment, file & memory */
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} Elf32_External_Phdr;
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/* 64-bit ELF program header. */
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typedef struct {
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unsigned char p_type[4]; /* Identifies program segment type */
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unsigned char p_flags[4]; /* Segment flags */
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unsigned char p_offset[8]; /* Segment file offset */
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unsigned char p_vaddr[8]; /* Segment virtual address */
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unsigned char p_paddr[8]; /* Segment physical address */
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unsigned char p_filesz[8]; /* Segment size in file */
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unsigned char p_memsz[8]; /* Segment size in memory */
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unsigned char p_align[8]; /* Segment alignment, file & memory */
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} Elf64_External_Phdr;
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/* 32-bit ELF section header */
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typedef struct {
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unsigned char sh_name[4]; /* Section name, index in string tbl */
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unsigned char sh_type[4]; /* Type of section */
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unsigned char sh_flags[4]; /* Miscellaneous section attributes */
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unsigned char sh_addr[4]; /* Section virtual addr at execution */
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unsigned char sh_offset[4]; /* Section file offset */
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unsigned char sh_size[4]; /* Size of section in bytes */
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unsigned char sh_link[4]; /* Index of another section */
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unsigned char sh_info[4]; /* Additional section information */
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unsigned char sh_addralign[4]; /* Section alignment */
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unsigned char sh_entsize[4]; /* Entry size if section holds table */
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} Elf32_External_Shdr;
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/* 64-bit ELF section header. */
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typedef struct {
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unsigned char sh_name[4]; /* Section name, index in string tbl */
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unsigned char sh_type[4]; /* Type of section */
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unsigned char sh_flags[8]; /* Miscellaneous section attributes */
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unsigned char sh_addr[8]; /* Section virtual addr at execution */
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unsigned char sh_offset[8]; /* Section file offset */
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unsigned char sh_size[8]; /* Size of section in bytes */
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unsigned char sh_link[4]; /* Index of another section */
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unsigned char sh_info[4]; /* Additional section information */
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unsigned char sh_addralign[8]; /* Section alignment */
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unsigned char sh_entsize[8]; /* Entry size if section holds table */
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} Elf64_External_Shdr;
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/* Values for sh_type field. */
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#define SHT_PROGBITS 1 /* Program data */
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#define SHT_STRTAB 3 /* A string table */
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/* Functions to fetch and store different ELF types, depending on the
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endianness and size. */
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struct elf_type_functions
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{
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unsigned short (*fetch_Elf_Half) (const unsigned char *);
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unsigned int (*fetch_Elf_Word) (const unsigned char *);
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ulong_type (*fetch_Elf_Addr) (const unsigned char *);
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void (*set_Elf_Half) (unsigned char *, unsigned short);
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void (*set_Elf_Word) (unsigned char *, unsigned int);
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void (*set_Elf_Addr) (unsigned char *, ulong_type);
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};
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static const struct elf_type_functions elf_big_32_functions =
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{
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simple_object_fetch_big_16,
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simple_object_fetch_big_32,
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simple_object_fetch_big_32_ulong,
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simple_object_set_big_16,
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simple_object_set_big_32,
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simple_object_set_big_32_ulong
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};
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static const struct elf_type_functions elf_little_32_functions =
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{
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simple_object_fetch_little_16,
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simple_object_fetch_little_32,
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simple_object_fetch_little_32_ulong,
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simple_object_set_little_16,
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simple_object_set_little_32,
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simple_object_set_little_32_ulong
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};
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#ifdef UNSIGNED_64BIT_TYPE
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static const struct elf_type_functions elf_big_64_functions =
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{
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simple_object_fetch_big_16,
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simple_object_fetch_big_32,
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simple_object_fetch_big_64,
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simple_object_set_big_16,
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simple_object_set_big_32,
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simple_object_set_big_64
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};
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static const struct elf_type_functions elf_little_64_functions =
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{
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simple_object_fetch_little_16,
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simple_object_fetch_little_32,
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simple_object_fetch_little_64,
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simple_object_set_little_16,
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simple_object_set_little_32,
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simple_object_set_little_64
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};
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#endif
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/* Hideous macro to fetch the value of a field from an external ELF
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struct of some sort. TYPEFUNCS is the set of type functions.
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BUFFER points to the external data. STRUCTTYPE is the appropriate
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struct type. FIELD is a field within the struct. TYPE is the type
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of the field in the struct: Elf_Half, Elf_Word, or Elf_Addr. */
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#define ELF_FETCH_STRUCT_FIELD(TYPEFUNCS, STRUCTTYPE, FIELD, BUFFER, TYPE) \
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((TYPEFUNCS)->fetch_ ## TYPE ((BUFFER) + offsetof (STRUCTTYPE, FIELD)))
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/* Even more hideous macro to fetch the value of FIELD from BUFFER.
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SIZE is 32 or 64. STRUCTTYPE is the name of the struct from
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elf/external.h: Ehdr, Shdr, etc. FIELD is the name of a field in
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the struct. TYPE is the type of the field in the struct: Elf_Half,
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Elf_Word, or Elf_Addr. */
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#define ELF_FETCH_SIZED_FIELD(TYPEFUNCS, SIZE, STRUCTTYPE, BUFFER, \
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FIELD, TYPE) \
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ELF_FETCH_STRUCT_FIELD (TYPEFUNCS, \
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Elf ## SIZE ## _External_ ## STRUCTTYPE, \
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FIELD, BUFFER, TYPE)
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/* Like ELF_FETCH_SIZED_FIELD but taking an ELFCLASS value. */
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#define ELF_FETCH_FIELD(TYPEFUNCS, CLASS, STRUCTTYPE, BUFFER, \
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FIELD, TYPE) \
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((CLASS) == ELFCLASS32 \
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? ELF_FETCH_SIZED_FIELD (TYPEFUNCS, 32, STRUCTTYPE, BUFFER, FIELD, \
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TYPE) \
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: ELF_FETCH_SIZED_FIELD (TYPEFUNCS, 64, STRUCTTYPE, BUFFER, FIELD, \
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TYPE))
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/* Hideous macro to set the value of a field in an external ELF
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structure to VAL. TYPEFUNCS is the set of type functions. BUFFER
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points to the external data. STRUCTTYPE is the appropriate
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structure type. FIELD is a field within the struct. TYPE is the
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type of the field in the struct: Elf_Half, Elf_Word, or
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Elf_Addr. */
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#define ELF_SET_STRUCT_FIELD(TYPEFUNCS, STRUCTTYPE, FIELD, BUFFER, TYPE, VAL) \
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(TYPEFUNCS)->set_ ## TYPE ((BUFFER) + offsetof (STRUCTTYPE, FIELD), (VAL))
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/* Even more hideous macro to set the value of FIELD in BUFFER to VAL.
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SIZE is 32 or 64. STRUCTTYPE is the name of the struct from
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elf/external.h: Ehdr, Shdr, etc. FIELD is the name of a field in
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the struct. TYPE is the type of the field in the struct: Elf_Half,
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Elf_Word, or Elf_Addr. */
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#define ELF_SET_SIZED_FIELD(TYPEFUNCS, SIZE, STRUCTTYPE, BUFFER, FIELD, \
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TYPE, VAL) \
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ELF_SET_STRUCT_FIELD (TYPEFUNCS, \
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Elf ## SIZE ## _External_ ## STRUCTTYPE, \
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FIELD, BUFFER, TYPE, VAL)
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/* Like ELF_SET_SIZED_FIELD but taking an ELFCLASS value. */
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#define ELF_SET_FIELD(TYPEFUNCS, CLASS, STRUCTTYPE, BUFFER, FIELD, \
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TYPE, VAL) \
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((CLASS) == ELFCLASS32 \
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? ELF_SET_SIZED_FIELD (TYPEFUNCS, 32, STRUCTTYPE, BUFFER, FIELD, \
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TYPE, VAL) \
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: ELF_SET_SIZED_FIELD (TYPEFUNCS, 64, STRUCTTYPE, BUFFER, FIELD, \
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TYPE, VAL))
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/* Private data for an simple_object_read. */
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struct simple_object_elf_read
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{
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/* Type functions. */
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const struct elf_type_functions* type_functions;
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/* Elf data. */
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unsigned char ei_data;
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/* Elf class. */
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unsigned char ei_class;
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/* ELF OS ABI. */
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unsigned char ei_osabi;
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/* Elf machine number. */
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unsigned short machine;
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/* Processor specific flags. */
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unsigned int flags;
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/* File offset of section headers. */
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ulong_type shoff;
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/* Number of sections. */
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unsigned int shnum;
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/* Index of string table section header. */
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unsigned int shstrndx;
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};
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/* Private data for an simple_object_attributes. */
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struct simple_object_elf_attributes
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{
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/* Type functions. */
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const struct elf_type_functions* type_functions;
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/* Elf data. */
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unsigned char ei_data;
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/* Elf class. */
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unsigned char ei_class;
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/* ELF OS ABI. */
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unsigned char ei_osabi;
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/* Elf machine number. */
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unsigned short machine;
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/* Processor specific flags. */
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unsigned int flags;
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};
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/* See if we have an ELF file. */
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static void *
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simple_object_elf_match (unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN],
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int descriptor, off_t offset,
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const char *segment_name ATTRIBUTE_UNUSED,
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const char **errmsg, int *err)
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{
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unsigned char ei_data;
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unsigned char ei_class;
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const struct elf_type_functions *type_functions;
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unsigned char ehdr[sizeof (Elf64_External_Ehdr)];
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struct simple_object_elf_read *eor;
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if (header[EI_MAG0] != ELFMAG0
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|| header[EI_MAG1] != ELFMAG1
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|| header[EI_MAG2] != ELFMAG2
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|| header[EI_MAG3] != ELFMAG3
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|| header[EI_VERSION] != EV_CURRENT)
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{
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*errmsg = NULL;
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*err = 0;
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return NULL;
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}
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ei_data = header[EI_DATA];
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if (ei_data != ELFDATA2LSB && ei_data != ELFDATA2MSB)
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{
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*errmsg = "unknown ELF endianness";
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*err = 0;
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return NULL;
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}
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ei_class = header[EI_CLASS];
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switch (ei_class)
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{
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case ELFCLASS32:
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type_functions = (ei_data == ELFDATA2LSB
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? &elf_little_32_functions
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: &elf_big_32_functions);
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break;
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case ELFCLASS64:
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#ifndef UNSIGNED_64BIT_TYPE
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*errmsg = "64-bit ELF objects not supported";
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*err = 0;
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return NULL;
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#else
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type_functions = (ei_data == ELFDATA2LSB
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? &elf_little_64_functions
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: &elf_big_64_functions);
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break;
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#endif
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default:
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*errmsg = "unrecognized ELF size";
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*err = 0;
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return NULL;
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}
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if (!simple_object_internal_read (descriptor, offset, ehdr, sizeof ehdr,
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errmsg, err))
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return NULL;
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eor = XNEW (struct simple_object_elf_read);
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eor->type_functions = type_functions;
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eor->ei_data = ei_data;
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eor->ei_class = ei_class;
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eor->ei_osabi = header[EI_OSABI];
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eor->machine = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr,
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e_machine, Elf_Half);
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eor->flags = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr,
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e_flags, Elf_Word);
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eor->shoff = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr,
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e_shoff, Elf_Addr);
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eor->shnum = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr,
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e_shnum, Elf_Half);
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eor->shstrndx = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr,
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e_shstrndx, Elf_Half);
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if ((eor->shnum == 0 || eor->shstrndx == SHN_XINDEX)
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&& eor->shoff != 0)
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{
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unsigned char shdr[sizeof (Elf64_External_Shdr)];
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/* Object file has more than 0xffff sections. */
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if (!simple_object_internal_read (descriptor, offset + eor->shoff, shdr,
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(ei_class == ELFCLASS32
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? sizeof (Elf32_External_Shdr)
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: sizeof (Elf64_External_Shdr)),
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errmsg, err))
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{
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XDELETE (eor);
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return NULL;
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}
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if (eor->shnum == 0)
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eor->shnum = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
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shdr, sh_size, Elf_Addr);
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if (eor->shstrndx == SHN_XINDEX)
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{
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eor->shstrndx = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
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shdr, sh_link, Elf_Word);
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/* Versions of the GNU binutils between 2.12 and 2.18 did
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not handle objects with more than SHN_LORESERVE sections
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correctly. All large section indexes were offset by
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0x100. There is more information at
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http://sourceware.org/bugzilla/show_bug.cgi?id-5900 .
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|
Fortunately these object files are easy to detect, as the
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GNU binutils always put the section header string table
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near the end of the list of sections. Thus if the
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section header string table index is larger than the
|
|
number of sections, then we know we have to subtract
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0x100 to get the real section index. */
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if (eor->shstrndx >= eor->shnum
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&& eor->shstrndx >= SHN_LORESERVE + 0x100)
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eor->shstrndx -= 0x100;
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}
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}
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|
|
if (eor->shstrndx >= eor->shnum)
|
|
{
|
|
*errmsg = "invalid ELF shstrndx >= shnum";
|
|
*err = 0;
|
|
XDELETE (eor);
|
|
return NULL;
|
|
}
|
|
|
|
return (void *) eor;
|
|
}
|
|
|
|
/* Find all sections in an ELF file. */
|
|
|
|
static const char *
|
|
simple_object_elf_find_sections (simple_object_read *sobj,
|
|
int (*pfn) (void *, const char *,
|
|
off_t offset, off_t length),
|
|
void *data,
|
|
int *err)
|
|
{
|
|
struct simple_object_elf_read *eor =
|
|
(struct simple_object_elf_read *) sobj->data;
|
|
const struct elf_type_functions *type_functions = eor->type_functions;
|
|
unsigned char ei_class = eor->ei_class;
|
|
size_t shdr_size;
|
|
unsigned int shnum;
|
|
unsigned char *shdrs;
|
|
const char *errmsg;
|
|
unsigned char *shstrhdr;
|
|
size_t name_size;
|
|
off_t shstroff;
|
|
unsigned char *names;
|
|
unsigned int i;
|
|
|
|
shdr_size = (ei_class == ELFCLASS32
|
|
? sizeof (Elf32_External_Shdr)
|
|
: sizeof (Elf64_External_Shdr));
|
|
|
|
/* Read the section headers. We skip section 0, which is not a
|
|
useful section. */
|
|
|
|
shnum = eor->shnum;
|
|
shdrs = XNEWVEC (unsigned char, shdr_size * (shnum - 1));
|
|
|
|
if (!simple_object_internal_read (sobj->descriptor,
|
|
sobj->offset + eor->shoff + shdr_size,
|
|
shdrs,
|
|
shdr_size * (shnum - 1),
|
|
&errmsg, err))
|
|
{
|
|
XDELETEVEC (shdrs);
|
|
return errmsg;
|
|
}
|
|
|
|
/* Read the section names. */
|
|
|
|
shstrhdr = shdrs + (eor->shstrndx - 1) * shdr_size;
|
|
name_size = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
|
|
shstrhdr, sh_size, Elf_Addr);
|
|
shstroff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
|
|
shstrhdr, sh_offset, Elf_Addr);
|
|
names = XNEWVEC (unsigned char, name_size);
|
|
if (!simple_object_internal_read (sobj->descriptor,
|
|
sobj->offset + shstroff,
|
|
names, name_size, &errmsg, err))
|
|
{
|
|
XDELETEVEC (names);
|
|
XDELETEVEC (shdrs);
|
|
return errmsg;
|
|
}
|
|
|
|
for (i = 1; i < shnum; ++i)
|
|
{
|
|
unsigned char *shdr;
|
|
unsigned int sh_name;
|
|
const char *name;
|
|
off_t offset;
|
|
off_t length;
|
|
|
|
shdr = shdrs + (i - 1) * shdr_size;
|
|
sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
|
|
shdr, sh_name, Elf_Word);
|
|
if (sh_name >= name_size)
|
|
{
|
|
*err = 0;
|
|
XDELETEVEC (names);
|
|
XDELETEVEC (shdrs);
|
|
return "ELF section name out of range";
|
|
}
|
|
|
|
name = (const char *) names + sh_name;
|
|
offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
|
|
shdr, sh_offset, Elf_Addr);
|
|
length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
|
|
shdr, sh_size, Elf_Addr);
|
|
|
|
if (!(*pfn) (data, name, offset, length))
|
|
break;
|
|
}
|
|
|
|
XDELETEVEC (names);
|
|
XDELETEVEC (shdrs);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Fetch the attributes for an simple_object_read. */
|
|
|
|
static void *
|
|
simple_object_elf_fetch_attributes (simple_object_read *sobj,
|
|
const char **errmsg ATTRIBUTE_UNUSED,
|
|
int *err ATTRIBUTE_UNUSED)
|
|
{
|
|
struct simple_object_elf_read *eor =
|
|
(struct simple_object_elf_read *) sobj->data;
|
|
struct simple_object_elf_attributes *ret;
|
|
|
|
ret = XNEW (struct simple_object_elf_attributes);
|
|
ret->type_functions = eor->type_functions;
|
|
ret->ei_data = eor->ei_data;
|
|
ret->ei_class = eor->ei_class;
|
|
ret->ei_osabi = eor->ei_osabi;
|
|
ret->machine = eor->machine;
|
|
ret->flags = eor->flags;
|
|
return ret;
|
|
}
|
|
|
|
/* Release the privata data for an simple_object_read. */
|
|
|
|
static void
|
|
simple_object_elf_release_read (void *data)
|
|
{
|
|
XDELETE (data);
|
|
}
|
|
|
|
/* Compare two attributes structures. */
|
|
|
|
static const char *
|
|
simple_object_elf_attributes_merge (void *todata, void *fromdata, int *err)
|
|
{
|
|
struct simple_object_elf_attributes *to =
|
|
(struct simple_object_elf_attributes *) todata;
|
|
struct simple_object_elf_attributes *from =
|
|
(struct simple_object_elf_attributes *) fromdata;
|
|
|
|
if (to->ei_data != from->ei_data || to->ei_class != from->ei_class)
|
|
{
|
|
*err = 0;
|
|
return "ELF object format mismatch";
|
|
}
|
|
|
|
if (to->machine != from->machine)
|
|
{
|
|
int ok;
|
|
|
|
/* EM_SPARC and EM_SPARC32PLUS are compatible and force an
|
|
output of EM_SPARC32PLUS. */
|
|
ok = 0;
|
|
switch (to->machine)
|
|
{
|
|
case EM_SPARC:
|
|
if (from->machine == EM_SPARC32PLUS)
|
|
{
|
|
to->machine = from->machine;
|
|
ok = 1;
|
|
}
|
|
break;
|
|
|
|
case EM_SPARC32PLUS:
|
|
if (from->machine == EM_SPARC)
|
|
ok = 1;
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (!ok)
|
|
{
|
|
*err = 0;
|
|
return "ELF machine number mismatch";
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Release the private data for an attributes structure. */
|
|
|
|
static void
|
|
simple_object_elf_release_attributes (void *data)
|
|
{
|
|
XDELETE (data);
|
|
}
|
|
|
|
/* Prepare to write out a file. */
|
|
|
|
static void *
|
|
simple_object_elf_start_write (void *attributes_data,
|
|
const char **errmsg ATTRIBUTE_UNUSED,
|
|
int *err ATTRIBUTE_UNUSED)
|
|
{
|
|
struct simple_object_elf_attributes *attrs =
|
|
(struct simple_object_elf_attributes *) attributes_data;
|
|
struct simple_object_elf_attributes *ret;
|
|
|
|
/* We're just going to record the attributes, but we need to make a
|
|
copy because the user may delete them. */
|
|
ret = XNEW (struct simple_object_elf_attributes);
|
|
*ret = *attrs;
|
|
return ret;
|
|
}
|
|
|
|
/* Write out an ELF ehdr. */
|
|
|
|
static int
|
|
simple_object_elf_write_ehdr (simple_object_write *sobj, int descriptor,
|
|
const char **errmsg, int *err)
|
|
{
|
|
struct simple_object_elf_attributes *attrs =
|
|
(struct simple_object_elf_attributes *) sobj->data;
|
|
const struct elf_type_functions* fns;
|
|
unsigned char cl;
|
|
size_t ehdr_size;
|
|
unsigned char buf[sizeof (Elf64_External_Ehdr)];
|
|
simple_object_write_section *section;
|
|
unsigned int shnum;
|
|
unsigned int shstrndx;
|
|
|
|
fns = attrs->type_functions;
|
|
cl = attrs->ei_class;
|
|
|
|
shnum = 0;
|
|
for (section = sobj->sections; section != NULL; section = section->next)
|
|
++shnum;
|
|
if (shnum > 0)
|
|
{
|
|
/* Add a section header for the dummy section and one for
|
|
.shstrtab. */
|
|
shnum += 2;
|
|
}
|
|
|
|
ehdr_size = (cl == ELFCLASS32
|
|
? sizeof (Elf32_External_Ehdr)
|
|
: sizeof (Elf64_External_Ehdr));
|
|
memset (buf, 0, sizeof (Elf64_External_Ehdr));
|
|
|
|
buf[EI_MAG0] = ELFMAG0;
|
|
buf[EI_MAG1] = ELFMAG1;
|
|
buf[EI_MAG2] = ELFMAG2;
|
|
buf[EI_MAG3] = ELFMAG3;
|
|
buf[EI_CLASS] = cl;
|
|
buf[EI_DATA] = attrs->ei_data;
|
|
buf[EI_VERSION] = EV_CURRENT;
|
|
buf[EI_OSABI] = attrs->ei_osabi;
|
|
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_type, Elf_Half, ET_REL);
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_machine, Elf_Half, attrs->machine);
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_version, Elf_Word, EV_CURRENT);
|
|
/* e_entry left as zero. */
|
|
/* e_phoff left as zero. */
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shoff, Elf_Addr, ehdr_size);
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_flags, Elf_Word, attrs->flags);
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_ehsize, Elf_Half, ehdr_size);
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_phentsize, Elf_Half,
|
|
(cl == ELFCLASS32
|
|
? sizeof (Elf32_External_Phdr)
|
|
: sizeof (Elf64_External_Phdr)));
|
|
/* e_phnum left as zero. */
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shentsize, Elf_Half,
|
|
(cl == ELFCLASS32
|
|
? sizeof (Elf32_External_Shdr)
|
|
: sizeof (Elf64_External_Shdr)));
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shnum, Elf_Half,
|
|
shnum >= SHN_LORESERVE ? 0 : shnum);
|
|
if (shnum == 0)
|
|
shstrndx = 0;
|
|
else
|
|
{
|
|
shstrndx = shnum - 1;
|
|
if (shstrndx >= SHN_LORESERVE)
|
|
shstrndx = SHN_XINDEX;
|
|
}
|
|
ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shstrndx, Elf_Half, shstrndx);
|
|
|
|
return simple_object_internal_write (descriptor, 0, buf, ehdr_size,
|
|
errmsg, err);
|
|
}
|
|
|
|
/* Write out an ELF shdr. */
|
|
|
|
static int
|
|
simple_object_elf_write_shdr (simple_object_write *sobj, int descriptor,
|
|
off_t offset, unsigned int sh_name,
|
|
unsigned int sh_type, unsigned int sh_flags,
|
|
unsigned int sh_offset, unsigned int sh_size,
|
|
unsigned int sh_link, unsigned int sh_addralign,
|
|
const char **errmsg, int *err)
|
|
{
|
|
struct simple_object_elf_attributes *attrs =
|
|
(struct simple_object_elf_attributes *) sobj->data;
|
|
const struct elf_type_functions* fns;
|
|
unsigned char cl;
|
|
size_t shdr_size;
|
|
unsigned char buf[sizeof (Elf64_External_Shdr)];
|
|
|
|
fns = attrs->type_functions;
|
|
cl = attrs->ei_class;
|
|
|
|
shdr_size = (cl == ELFCLASS32
|
|
? sizeof (Elf32_External_Shdr)
|
|
: sizeof (Elf64_External_Shdr));
|
|
memset (buf, 0, sizeof (Elf64_External_Shdr));
|
|
|
|
ELF_SET_FIELD (fns, cl, Shdr, buf, sh_name, Elf_Word, sh_name);
|
|
ELF_SET_FIELD (fns, cl, Shdr, buf, sh_type, Elf_Word, sh_type);
|
|
ELF_SET_FIELD (fns, cl, Shdr, buf, sh_flags, Elf_Addr, sh_flags);
|
|
ELF_SET_FIELD (fns, cl, Shdr, buf, sh_offset, Elf_Addr, sh_offset);
|
|
ELF_SET_FIELD (fns, cl, Shdr, buf, sh_size, Elf_Addr, sh_size);
|
|
ELF_SET_FIELD (fns, cl, Shdr, buf, sh_link, Elf_Word, sh_link);
|
|
/* sh_info left as zero. */
|
|
ELF_SET_FIELD (fns, cl, Shdr, buf, sh_addralign, Elf_Addr, sh_addralign);
|
|
/* sh_entsize left as zero. */
|
|
|
|
return simple_object_internal_write (descriptor, offset, buf, shdr_size,
|
|
errmsg, err);
|
|
}
|
|
|
|
/* Write out a complete ELF file.
|
|
Ehdr
|
|
initial dummy Shdr
|
|
user-created Shdrs
|
|
.shstrtab Shdr
|
|
user-created section data
|
|
.shstrtab data */
|
|
|
|
static const char *
|
|
simple_object_elf_write_to_file (simple_object_write *sobj, int descriptor,
|
|
int *err)
|
|
{
|
|
struct simple_object_elf_attributes *attrs =
|
|
(struct simple_object_elf_attributes *) sobj->data;
|
|
unsigned char cl;
|
|
size_t ehdr_size;
|
|
size_t shdr_size;
|
|
const char *errmsg;
|
|
simple_object_write_section *section;
|
|
unsigned int shnum;
|
|
size_t shdr_offset;
|
|
size_t sh_offset;
|
|
unsigned int first_sh_size;
|
|
unsigned int first_sh_link;
|
|
size_t sh_name;
|
|
unsigned char zero;
|
|
|
|
if (!simple_object_elf_write_ehdr (sobj, descriptor, &errmsg, err))
|
|
return errmsg;
|
|
|
|
cl = attrs->ei_class;
|
|
if (cl == ELFCLASS32)
|
|
{
|
|
ehdr_size = sizeof (Elf32_External_Ehdr);
|
|
shdr_size = sizeof (Elf32_External_Shdr);
|
|
}
|
|
else
|
|
{
|
|
ehdr_size = sizeof (Elf64_External_Ehdr);
|
|
shdr_size = sizeof (Elf64_External_Shdr);
|
|
}
|
|
|
|
shnum = 0;
|
|
for (section = sobj->sections; section != NULL; section = section->next)
|
|
++shnum;
|
|
if (shnum == 0)
|
|
return NULL;
|
|
|
|
/* Add initial dummy Shdr and .shstrtab. */
|
|
shnum += 2;
|
|
|
|
shdr_offset = ehdr_size;
|
|
sh_offset = shdr_offset + shnum * shdr_size;
|
|
|
|
if (shnum < SHN_LORESERVE)
|
|
first_sh_size = 0;
|
|
else
|
|
first_sh_size = shnum;
|
|
if (shnum - 1 < SHN_LORESERVE)
|
|
first_sh_link = 0;
|
|
else
|
|
first_sh_link = shnum - 1;
|
|
if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset,
|
|
0, 0, 0, 0, first_sh_size, first_sh_link,
|
|
0, &errmsg, err))
|
|
return errmsg;
|
|
|
|
shdr_offset += shdr_size;
|
|
|
|
sh_name = 1;
|
|
for (section = sobj->sections; section != NULL; section = section->next)
|
|
{
|
|
size_t mask;
|
|
size_t new_sh_offset;
|
|
size_t sh_size;
|
|
struct simple_object_write_section_buffer *buffer;
|
|
|
|
mask = (1U << section->align) - 1;
|
|
new_sh_offset = sh_offset + mask;
|
|
new_sh_offset &= ~ mask;
|
|
while (new_sh_offset > sh_offset)
|
|
{
|
|
unsigned char zeroes[16];
|
|
size_t write;
|
|
|
|
memset (zeroes, 0, sizeof zeroes);
|
|
write = new_sh_offset - sh_offset;
|
|
if (write > sizeof zeroes)
|
|
write = sizeof zeroes;
|
|
if (!simple_object_internal_write (descriptor, sh_offset, zeroes,
|
|
write, &errmsg, err))
|
|
return errmsg;
|
|
sh_offset += write;
|
|
}
|
|
|
|
sh_size = 0;
|
|
for (buffer = section->buffers; buffer != NULL; buffer = buffer->next)
|
|
{
|
|
if (!simple_object_internal_write (descriptor, sh_offset + sh_size,
|
|
((const unsigned char *)
|
|
buffer->buffer),
|
|
buffer->size, &errmsg, err))
|
|
return errmsg;
|
|
sh_size += buffer->size;
|
|
}
|
|
|
|
if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset,
|
|
sh_name, SHT_PROGBITS, 0, sh_offset,
|
|
sh_size, 0, 1U << section->align,
|
|
&errmsg, err))
|
|
return errmsg;
|
|
|
|
shdr_offset += shdr_size;
|
|
sh_name += strlen (section->name) + 1;
|
|
sh_offset += sh_size;
|
|
}
|
|
|
|
if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset,
|
|
sh_name, SHT_STRTAB, 0, sh_offset,
|
|
sh_name + strlen (".shstrtab") + 1, 0,
|
|
1, &errmsg, err))
|
|
return errmsg;
|
|
|
|
/* .shstrtab has a leading zero byte. */
|
|
zero = 0;
|
|
if (!simple_object_internal_write (descriptor, sh_offset, &zero, 1,
|
|
&errmsg, err))
|
|
return errmsg;
|
|
++sh_offset;
|
|
|
|
for (section = sobj->sections; section != NULL; section = section->next)
|
|
{
|
|
size_t len;
|
|
|
|
len = strlen (section->name) + 1;
|
|
if (!simple_object_internal_write (descriptor, sh_offset,
|
|
(const unsigned char *) section->name,
|
|
len, &errmsg, err))
|
|
return errmsg;
|
|
sh_offset += len;
|
|
}
|
|
|
|
if (!simple_object_internal_write (descriptor, sh_offset,
|
|
(const unsigned char *) ".shstrtab",
|
|
strlen (".shstrtab") + 1, &errmsg, err))
|
|
return errmsg;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Release the private data for an simple_object_write structure. */
|
|
|
|
static void
|
|
simple_object_elf_release_write (void *data)
|
|
{
|
|
XDELETE (data);
|
|
}
|
|
|
|
/* The ELF functions. */
|
|
|
|
const struct simple_object_functions simple_object_elf_functions =
|
|
{
|
|
simple_object_elf_match,
|
|
simple_object_elf_find_sections,
|
|
simple_object_elf_fetch_attributes,
|
|
simple_object_elf_release_read,
|
|
simple_object_elf_attributes_merge,
|
|
simple_object_elf_release_attributes,
|
|
simple_object_elf_start_write,
|
|
simple_object_elf_write_to_file,
|
|
simple_object_elf_release_write
|
|
};
|