205 lines
5.8 KiB
C
205 lines
5.8 KiB
C
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/*-
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* Copyright (c) 2006,2008 Joseph Koshy
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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#include <sys/cdefs.h>
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#include <assert.h>
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#include <gelf.h>
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#include <libelf.h>
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#include <stdlib.h>
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#include "_libelf.h"
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ELFTC_VCSID("$Id: libelf_ehdr.c 2225 2011-11-26 18:55:54Z jkoshy $");
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/*
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* Retrieve counts for sections, phdrs and the section string table index
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* from section header #0 of the ELF object.
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*/
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static int
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_libelf_load_extended(Elf *e, int ec, uint64_t shoff, uint16_t phnum,
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uint16_t strndx)
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{
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Elf_Scn *scn;
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size_t fsz;
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int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
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uint32_t shtype;
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assert(STAILQ_EMPTY(&e->e_u.e_elf.e_scn));
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fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, 1);
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assert(fsz > 0);
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if (e->e_rawsize < shoff + fsz) { /* raw file too small */
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LIBELF_SET_ERROR(HEADER, 0);
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return (0);
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}
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if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL)
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return (0);
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xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
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(*xlator)((char *) &scn->s_shdr, sizeof(scn->s_shdr),
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e->e_rawfile + shoff, (size_t) 1,
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e->e_byteorder != LIBELF_PRIVATE(byteorder));
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#define GET_SHDR_MEMBER(M) ((ec == ELFCLASS32) ? scn->s_shdr.s_shdr32.M : \
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scn->s_shdr.s_shdr64.M)
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if ((shtype = GET_SHDR_MEMBER(sh_type)) != SHT_NULL) {
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LIBELF_SET_ERROR(SECTION, 0);
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return (0);
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}
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e->e_u.e_elf.e_nscn = GET_SHDR_MEMBER(sh_size);
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e->e_u.e_elf.e_nphdr = (phnum != PN_XNUM) ? phnum :
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GET_SHDR_MEMBER(sh_info);
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e->e_u.e_elf.e_strndx = (strndx != SHN_XINDEX) ? strndx :
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GET_SHDR_MEMBER(sh_link);
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#undef GET_SHDR_MEMBER
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return (1);
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}
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#define EHDR_INIT(E,SZ) do { \
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Elf##SZ##_Ehdr *eh = (E); \
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eh->e_ident[EI_MAG0] = ELFMAG0; \
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eh->e_ident[EI_MAG1] = ELFMAG1; \
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eh->e_ident[EI_MAG2] = ELFMAG2; \
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eh->e_ident[EI_MAG3] = ELFMAG3; \
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eh->e_ident[EI_CLASS] = ELFCLASS##SZ; \
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eh->e_ident[EI_DATA] = ELFDATANONE; \
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eh->e_ident[EI_VERSION] = LIBELF_PRIVATE(version); \
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eh->e_machine = EM_NONE; \
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eh->e_type = ELF_K_NONE; \
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eh->e_version = LIBELF_PRIVATE(version); \
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} while (0)
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void *
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_libelf_ehdr(Elf *e, int ec, int allocate)
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{
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void *ehdr;
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size_t fsz, msz;
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uint16_t phnum, shnum, strndx;
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uint64_t shoff;
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int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
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assert(ec == ELFCLASS32 || ec == ELFCLASS64);
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if (e == NULL || e->e_kind != ELF_K_ELF) {
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LIBELF_SET_ERROR(ARGUMENT, 0);
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return (NULL);
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}
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if (e->e_class != ELFCLASSNONE && e->e_class != ec) {
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LIBELF_SET_ERROR(CLASS, 0);
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return (NULL);
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}
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if (e->e_version != EV_CURRENT) {
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LIBELF_SET_ERROR(VERSION, 0);
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return (NULL);
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}
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if (e->e_class == ELFCLASSNONE)
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e->e_class = ec;
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if (ec == ELFCLASS32)
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ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr32;
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else
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ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr64;
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if (ehdr != NULL) /* already have a translated ehdr */
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return (ehdr);
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fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1);
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assert(fsz > 0);
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if (e->e_cmd != ELF_C_WRITE && e->e_rawsize < fsz) {
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LIBELF_SET_ERROR(HEADER, 0);
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return (NULL);
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}
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msz = _libelf_msize(ELF_T_EHDR, ec, EV_CURRENT);
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assert(msz > 0);
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if ((ehdr = calloc((size_t) 1, msz)) == NULL) {
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LIBELF_SET_ERROR(RESOURCE, 0);
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return (NULL);
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}
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if (ec == ELFCLASS32) {
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e->e_u.e_elf.e_ehdr.e_ehdr32 = ehdr;
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EHDR_INIT(ehdr,32);
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} else {
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e->e_u.e_elf.e_ehdr.e_ehdr64 = ehdr;
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EHDR_INIT(ehdr,64);
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}
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if (allocate)
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e->e_flags |= ELF_F_DIRTY;
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if (e->e_cmd == ELF_C_WRITE)
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return (ehdr);
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xlator = _libelf_get_translator(ELF_T_EHDR, ELF_TOMEMORY, ec);
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(*xlator)(ehdr, msz, e->e_rawfile, (size_t) 1,
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e->e_byteorder != LIBELF_PRIVATE(byteorder));
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/*
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* If extended numbering is being used, read the correct
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* number of sections and program header entries.
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*/
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if (ec == ELFCLASS32) {
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phnum = ((Elf32_Ehdr *) ehdr)->e_phnum;
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shnum = ((Elf32_Ehdr *) ehdr)->e_shnum;
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shoff = ((Elf32_Ehdr *) ehdr)->e_shoff;
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strndx = ((Elf32_Ehdr *) ehdr)->e_shstrndx;
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} else {
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phnum = ((Elf64_Ehdr *) ehdr)->e_phnum;
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shnum = ((Elf64_Ehdr *) ehdr)->e_shnum;
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shoff = ((Elf64_Ehdr *) ehdr)->e_shoff;
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strndx = ((Elf64_Ehdr *) ehdr)->e_shstrndx;
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}
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if (shnum >= SHN_LORESERVE ||
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(shoff == 0LL && (shnum != 0 || phnum == PN_XNUM ||
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strndx == SHN_XINDEX))) {
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LIBELF_SET_ERROR(HEADER, 0);
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return (NULL);
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}
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if (shnum != 0 || shoff == 0LL) { /* not using extended numbering */
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e->e_u.e_elf.e_nphdr = phnum;
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e->e_u.e_elf.e_nscn = shnum;
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e->e_u.e_elf.e_strndx = strndx;
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} else if (_libelf_load_extended(e, ec, shoff, phnum, strndx) == 0)
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return (NULL);
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return (ehdr);
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}
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