| /*- | |
| * Copyright (c) 2006 Joseph Koshy | |
| * All rights reserved. | |
| * | |
| * Redistribution and use in source and binary forms, with or without | |
| * modification, are permitted provided that the following conditions | |
| * are met: | |
| * 1. Redistributions of source code must retain the above copyright | |
| * notice, this list of conditions and the following disclaimer. | |
| * 2. Redistributions in binary form must reproduce the above copyright | |
| * notice, this list of conditions and the following disclaimer in the | |
| * documentation and/or other materials provided with the distribution. | |
| * | |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| * SUCH DAMAGE. | |
| */ | |
| #include <assert.h> | |
| #include <errno.h> | |
| #include <stddef.h> | |
| #include <stdlib.h> | |
| #include "gelf.h" | |
| #include "libelf.h" | |
| #include "_libelf.h" | |
| /* | |
| * Load an ELF section table and create a list of Elf_Scn structures. | |
| */ | |
| static int | |
| _libelf_load_scn(Elf *e, void *ehdr) | |
| { | |
| int ec, swapbytes; | |
| size_t fsz, i, shnum; | |
| uint64_t shoff; | |
| char *src; | |
| Elf32_Ehdr *eh32; | |
| Elf64_Ehdr *eh64; | |
| Elf_Scn *scn; | |
| void (*xlator)(char *_d, char *_s, size_t _c, int _swap); | |
| assert(e != NULL); | |
| assert(ehdr != NULL); | |
| assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0); | |
| #define CHECK_EHDR(E,EH) do { \ | |
| if (fsz != (EH)->e_shentsize || \ | |
| shoff + fsz * shnum > e->e_rawsize) { \ | |
| LIBELF_SET_ERROR(HEADER, 0); \ | |
| return (0); \ | |
| } \ | |
| } while (0) | |
| ec = e->e_class; | |
| fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); | |
| assert(fsz > 0); | |
| shnum = e->e_u.e_elf.e_nscn; | |
| if (ec == ELFCLASS32) { | |
| eh32 = (Elf32_Ehdr *) ehdr; | |
| shoff = (uint64_t) eh32->e_shoff; | |
| CHECK_EHDR(e, eh32); | |
| } else { | |
| eh64 = (Elf64_Ehdr *) ehdr; | |
| shoff = eh64->e_shoff; | |
| CHECK_EHDR(e, eh64); | |
| } | |
| xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); | |
| swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder); | |
| src = e->e_rawfile + shoff; | |
| /* | |
| * If the file is using extended numbering then section #0 | |
| * would have already been read in. | |
| */ | |
| i = 0; | |
| if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { | |
| assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) == | |
| STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next)); | |
| i = 1; | |
| src += fsz; | |
| } | |
| for (; i < shnum; i++, src += fsz) { | |
| if ((scn = _libelf_allocate_scn(e, i)) == NULL) | |
| return (0); | |
| (*xlator)((char *) &scn->s_shdr, src, (size_t) 1, swapbytes); | |
| if (ec == ELFCLASS32) { | |
| scn->s_offset = scn->s_rawoff = | |
| scn->s_shdr.s_shdr32.sh_offset; | |
| scn->s_size = scn->s_shdr.s_shdr32.sh_size; | |
| } else { | |
| scn->s_offset = scn->s_rawoff = | |
| scn->s_shdr.s_shdr64.sh_offset; | |
| scn->s_size = scn->s_shdr.s_shdr64.sh_size; | |
| } | |
| } | |
| e->e_flags |= LIBELF_F_SHDRS_LOADED; | |
| return (1); | |
| } | |
| Elf_Scn * | |
| elf_getscn(Elf *e, size_t index) | |
| { | |
| int ec; | |
| void *ehdr; | |
| Elf_Scn *s; | |
| if (e == NULL || e->e_kind != ELF_K_ELF || | |
| ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) { | |
| LIBELF_SET_ERROR(ARGUMENT, 0); | |
| return (NULL); | |
| } | |
| if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) | |
| return (NULL); | |
| if (e->e_cmd != ELF_C_WRITE && | |
| (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && | |
| _libelf_load_scn(e, ehdr) == 0) | |
| return (NULL); | |
| STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) | |
| if (s->s_ndx == index) | |
| return (s); | |
| LIBELF_SET_ERROR(ARGUMENT, 0); | |
| return (NULL); | |
| } | |
| size_t | |
| elf_ndxscn(Elf_Scn *s) | |
| { | |
| if (s == NULL) { | |
| LIBELF_SET_ERROR(ARGUMENT, 0); | |
| return (SHN_UNDEF); | |
| } | |
| return (s->s_ndx); | |
| } | |
| Elf_Scn * | |
| elf_newscn(Elf *e) | |
| { | |
| int ec; | |
| void *ehdr; | |
| Elf_Scn *scn; | |
| if (e == NULL || e->e_kind != ELF_K_ELF) { | |
| LIBELF_SET_ERROR(ARGUMENT, 0); | |
| return (NULL); | |
| } | |
| if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { | |
| LIBELF_SET_ERROR(CLASS, 0); | |
| return (NULL); | |
| } | |
| if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) | |
| return (NULL); | |
| /* | |
| * The application may be asking for a new section descriptor | |
| * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We | |
| * need to bring in the existing section information before | |
| * appending a new one to the list. | |
| * | |
| * Per the ELF(3) API, an application is allowed to open a | |
| * file using ELF_C_READ, mess with its internal structure and | |
| * use elf_update(...,ELF_C_NULL) to compute its new layout. | |
| */ | |
| if (e->e_cmd != ELF_C_WRITE && | |
| (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && | |
| _libelf_load_scn(e, ehdr) == 0) | |
| return (NULL); | |
| if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { | |
| assert(e->e_u.e_elf.e_nscn == 0); | |
| if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) == | |
| NULL) | |
| return (NULL); | |
| e->e_u.e_elf.e_nscn++; | |
| } | |
| assert(e->e_u.e_elf.e_nscn > 0); | |
| if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL) | |
| return (NULL); | |
| e->e_u.e_elf.e_nscn++; | |
| (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY); | |
| return (scn); | |
| } | |
| Elf_Scn * | |
| elf_nextscn(Elf *e, Elf_Scn *s) | |
| { | |
| if (e == NULL || (e->e_kind != ELF_K_ELF) || | |
| (s && s->s_elf != e)) { | |
| LIBELF_SET_ERROR(ARGUMENT, 0); | |
| return (NULL); | |
| } | |
| return (s == NULL ? elf_getscn(e, (size_t) 1) : | |
| STAILQ_NEXT(s, s_next)); | |
| } |