diff -r 1af5c1be89f8 -r 92d87f2e53c2 tools/elf4rom/libs/libelf-0.8.10/lib/checksum.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tools/elf4rom/libs/libelf-0.8.10/lib/checksum.c Fri Jan 15 09:07:44 2010 +0000 @@ -0,0 +1,178 @@ +/* +checksum.c - implementation of the elf{32,64}_checksum(3) functions. +Copyright (C) 1995 - 2001 Michael Riepe + +This library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public +License as published by the Free Software Foundation; either +version 2 of the License, or (at your option) any later version. + +This library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with this library; if not, write to the Free Software +Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA +*/ + +#include + +#ifndef lint +static const char rcsid[] = "@(#) $Id: checksum.c,v 1.6 2005/05/21 15:39:20 michael Exp $"; +#endif /* lint */ + +/* + * Compatibility note: + * + * The algorithm used in {elf32,elf64,gelf}_checksum() does not seem to + * be documented. I hope I got it right. My implementation does the + * following: + * + * - skip sections that do not have the SHF_ALLOC flag set + * - skip sections of type SHT_NULL, SHT_NOBITS, SHT_DYNSYM and + * SHT_DYNAMIC + * - add all data bytes from the remaining sections, modulo 2**32 + * - add upper and lower half of the result + * - subtract 0xffff if the result is > 0xffff + * - if any error occurs, return 0L + */ + +static int +skip_section(Elf_Scn *scn, unsigned cls) { + if (cls == ELFCLASS32) { + Elf32_Shdr *shdr = &scn->s_shdr32; + + if (!(shdr->sh_flags & SHF_ALLOC)) { + return 1; + } + switch (shdr->sh_type) { + case SHT_NULL: + case SHT_NOBITS: + /* Solaris seems to ignore these, too */ + case SHT_DYNSYM: + case SHT_DYNAMIC: + return 1; + } + } +#if __LIBELF64 + else if (cls == ELFCLASS64) { + Elf64_Shdr *shdr = &scn->s_shdr64; + + if (!(shdr->sh_flags & SHF_ALLOC)) { + return 1; + } + switch (shdr->sh_type) { + case SHT_NULL: + case SHT_NOBITS: + /* Solaris seems to ignore these, too */ + case SHT_DYNSYM: + case SHT_DYNAMIC: + return 1; + } + } +#endif /* __LIBELF64 */ + else { + seterr(ERROR_UNIMPLEMENTED); + } + return 0; +} + +static long +add_bytes(unsigned char *ptr, size_t len) { + long csum = 0; + + while (len--) { + csum += *ptr++; + } + return csum; +} + +static long +_elf_csum(Elf *elf) { + long csum = 0; + Elf_Data *data; + Elf_Scn *scn; + + if (!elf->e_ehdr && !_elf_cook(elf)) { + /* propagate errors from _elf_cook */ + return 0L; + } + seterr(0); + for (scn = elf->e_scn_1; scn; scn = scn->s_link) { + if (scn->s_index == SHN_UNDEF || skip_section(scn, elf->e_class)) { + continue; + } + data = NULL; + while ((data = elf_getdata(scn, data))) { + if (data->d_size) { + if (data->d_buf == NULL) { + seterr(ERROR_NULLBUF); + return 0L; + } + csum += add_bytes(data->d_buf, data->d_size); + } + } + } + if (_elf_errno) { + return 0L; + } + csum = (csum & 0xffff) + ((csum >> 16) & 0xffff); + if (csum > 0xffff) { + csum -= 0xffff; + } + return csum; +} + +long +elf32_checksum(Elf *elf) { + if (elf) { + if (elf->e_kind != ELF_K_ELF) { + seterr(ERROR_NOTELF); + } + else if (elf->e_class != ELFCLASS32) { + seterr(ERROR_CLASSMISMATCH); + } + else { + return _elf_csum(elf); + } + } + return 0L; +} + +#if __LIBELF64 + +long +elf64_checksum(Elf *elf) { + if (elf) { + if (elf->e_kind != ELF_K_ELF) { + seterr(ERROR_NOTELF); + } + else if (elf->e_class != ELFCLASS64) { + seterr(ERROR_CLASSMISMATCH); + } + else { + return _elf_csum(elf); + } + } + return 0L; +} + +long +gelf_checksum(Elf *elf) { + if (elf) { + if (elf->e_kind != ELF_K_ELF) { + seterr(ERROR_NOTELF); + } + else if (!valid_class(elf->e_class)) { + seterr(ERROR_UNKNOWN_CLASS); + } + else { + return _elf_csum(elf); + } + } + return 0L; +} + +#endif /* __LIBELF64 */