5e6220d9d0
longer includes machine/elf.h. * consumers of elf.h now use the minimalist elf header possible. This change is motivated by Binutils 2.11.0 and too much clashing over our base elf headers and the Binutils elf headers.
392 lines
10 KiB
C
392 lines
10 KiB
C
/*
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* Copyright (c) 1997 Christopher G. Demetriou. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Christopher G. Demetriou
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* for the NetBSD Project.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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__RCSID("$NetBSD: exec_elf32.c,v 1.4 1997/08/12 06:07:24 mikel Exp $");
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#endif
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static const char rcsid[] =
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"$FreeBSD$";
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#endif
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#ifndef ELFSIZE
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#define ELFSIZE 32
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#endif
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "extern.h"
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#if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \
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(defined(NLIST_ELF64) && (ELFSIZE == 64))
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#include <machine/elf.h>
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#define CONCAT(x,y) __CONCAT(x,y)
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#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
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#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
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#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE))
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#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
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struct listelem {
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struct listelem *next;
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void *mem;
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off_t file;
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size_t size;
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};
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static ssize_t
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xreadatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
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{
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ssize_t rv;
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if (lseek(fd, off, SEEK_SET) != off) {
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perror(fn);
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return -1;
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}
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if ((rv = read(fd, buf, size)) != size) {
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fprintf(stderr, "%s: read error: %s\n", fn,
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rv == -1 ? strerror(errno) : "short read");
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return -1;
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}
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return size;
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}
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static ssize_t
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xwriteatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
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{
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ssize_t rv;
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if (lseek(fd, off, SEEK_SET) != off) {
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perror(fn);
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return -1;
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}
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if ((rv = write(fd, buf, size)) != size) {
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fprintf(stderr, "%s: write error: %s\n", fn,
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rv == -1 ? strerror(errno) : "short write");
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return -1;
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}
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return size;
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}
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static void *
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xmalloc(size_t size, const char *fn, const char *use)
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{
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void *rv;
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rv = malloc(size);
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if (rv == NULL)
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fprintf(stderr, "%s: out of memory (allocating for %s)\n",
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fn, use);
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return (rv);
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}
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int
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ELFNAMEEND(check)(int fd, const char *fn)
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{
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Elf_Ehdr eh;
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struct stat sb;
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/*
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* Check the header to maek sure it's an ELF file (of the
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* appropriate size).
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*/
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if (fstat(fd, &sb) == -1)
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return 0;
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if (sb.st_size < sizeof eh)
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return 0;
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if (read(fd, &eh, sizeof eh) != sizeof eh)
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return 0;
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if (IS_ELF(eh) == 0)
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return 0;
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switch (eh.e_machine) {
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case EM_386: break;
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case EM_ALPHA: break;
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/* ELFDEFNNAME(MACHDEP_ID_CASES) */
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default:
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return 0;
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}
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return 1;
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}
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int
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ELFNAMEEND(hide)(int fd, const char *fn)
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{
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Elf_Ehdr ehdr;
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Elf_Shdr *shdrp = NULL, *symtabshdr, *strtabshdr;
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Elf_Sym *symtabp = NULL;
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char *strtabp = NULL;
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Elf_Word *symfwmap = NULL, *symrvmap = NULL, nsyms, nlocalsyms, ewi;
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struct listelem *relalist = NULL, *rellist = NULL, *tmpl;
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ssize_t shdrsize;
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int rv, i, weird;
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rv = 0;
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if (xreadatoff(fd, &ehdr, 0, sizeof ehdr, fn) != sizeof ehdr)
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goto bad;
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shdrsize = ehdr.e_shnum * ehdr.e_shentsize;
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if ((shdrp = xmalloc(shdrsize, fn, "section header table")) == NULL)
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goto bad;
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if (xreadatoff(fd, shdrp, ehdr.e_shoff, shdrsize, fn) != shdrsize)
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goto bad;
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symtabshdr = strtabshdr = NULL;
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weird = 0;
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for (i = 0; i < ehdr.e_shnum; i++) {
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switch (shdrp[i].sh_type) {
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case SHT_SYMTAB:
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if (symtabshdr != NULL)
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weird = 1;
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symtabshdr = &shdrp[i];
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strtabshdr = &shdrp[shdrp[i].sh_link];
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break;
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case SHT_RELA:
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tmpl = xmalloc(sizeof *tmpl, fn, "rela list element");
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if (tmpl == NULL)
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goto bad;
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tmpl->mem = NULL;
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tmpl->file = shdrp[i].sh_offset;
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tmpl->size = shdrp[i].sh_size;
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tmpl->next = relalist;
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relalist = tmpl;
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break;
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case SHT_REL:
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tmpl = xmalloc(sizeof *tmpl, fn, "rel list element");
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if (tmpl == NULL)
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goto bad;
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tmpl->mem = NULL;
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tmpl->file = shdrp[i].sh_offset;
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tmpl->size = shdrp[i].sh_size;
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tmpl->next = rellist;
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rellist = tmpl;
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break;
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}
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}
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if (symtabshdr == NULL)
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goto out;
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if (strtabshdr == NULL)
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weird = 1;
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if (weird) {
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fprintf(stderr, "%s: weird executable (unsupported)\n", fn);
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goto bad;
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}
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/*
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* load up everything we need
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*/
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/* symbol table */
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if ((symtabp = xmalloc(symtabshdr->sh_size, fn, "symbol table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, symtabp, symtabshdr->sh_offset, symtabshdr->sh_size,
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fn) != symtabshdr->sh_size)
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goto bad;
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/* string table */
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if ((strtabp = xmalloc(strtabshdr->sh_size, fn, "string table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, strtabp, strtabshdr->sh_offset, strtabshdr->sh_size,
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fn) != strtabshdr->sh_size)
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goto bad;
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/* any rela tables */
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for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
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if ((tmpl->mem = xmalloc(tmpl->size, fn, "rela table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
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tmpl->size)
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goto bad;
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}
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/* any rel tables */
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for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
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if ((tmpl->mem = xmalloc(tmpl->size, fn, "rel table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
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tmpl->size)
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goto bad;
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}
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/* Prepare data structures for symbol movement. */
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nsyms = symtabshdr->sh_size / symtabshdr->sh_entsize;
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nlocalsyms = symtabshdr->sh_info;
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if ((symfwmap = xmalloc(nsyms * sizeof (Elf_Word), fn,
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"symbol forward mapping table")) == NULL)
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goto bad;
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if ((symrvmap = xmalloc(nsyms * sizeof (Elf_Word), fn,
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"symbol reverse mapping table")) == NULL)
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goto bad;
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/* init location -> symbol # table */
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for (ewi = 0; ewi < nsyms; ewi++)
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symrvmap[ewi] = ewi;
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/* move symbols, making them local */
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for (ewi = nlocalsyms; ewi < nsyms; ewi++) {
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Elf_Sym *sp, symswap;
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Elf_Word mapswap;
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sp = &symtabp[ewi];
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/* if it's on our keep list, don't move it */
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if (in_keep_list(strtabp + sp->st_name))
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continue;
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/* if it's an undefined symbol, keep it */
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if (sp->st_shndx == SHN_UNDEF)
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continue;
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/* adjust the symbol so that it's local */
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sp->st_info =
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ELF_ST_INFO(STB_LOCAL, sp->st_info);
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/* (STB_LOCAL << 4) | ELF_SYM_TYPE(sp->st_info); *//* XXX */
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/*
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* move the symbol to its new location
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*/
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/* note that symbols in those locations have been swapped */
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mapswap = symrvmap[ewi];
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symrvmap[ewi] = symrvmap[nlocalsyms];
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symrvmap[nlocalsyms] = mapswap;
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/* and swap the symbols */
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symswap = *sp;
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*sp = symtabp[nlocalsyms];
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symtabp[nlocalsyms] = symswap;
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nlocalsyms++; /* note new local sym */
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}
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symtabshdr->sh_info = nlocalsyms;
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/* set up symbol # -> location mapping table */
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for (ewi = 0; ewi < nsyms; ewi++)
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symfwmap[symrvmap[ewi]] = ewi;
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/* any rela tables */
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for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
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Elf_Rela *relap = tmpl->mem;
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for (ewi = 0; ewi < tmpl->size / sizeof(*relap); ewi++) {
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relap[ewi].r_info =
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#if (ELFSIZE == 32) /* XXX */
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symfwmap[ELF_R_SYM(relap[ewi].r_info)] << 8 |
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ELF_R_TYPE(relap[ewi].r_info);
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#elif (ELFSIZE == 64) /* XXX */
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symfwmap[ELF_R_SYM(relap[ewi].r_info)] << 32 |
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ELF_R_TYPE(relap[ewi].r_info);
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#endif /* XXX */
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}
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}
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/* any rel tables */
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for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
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Elf_Rel *relp = tmpl->mem;
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for (ewi = 0; ewi < tmpl->size / sizeof *relp; ewi++) {
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relp[ewi].r_info =
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#if (ELFSIZE == 32) /* XXX */
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symfwmap[ELF_R_SYM(relp[ewi].r_info)] << 8 |
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ELF_R_TYPE(relp[ewi].r_info);
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#elif (ELFSIZE == 64) /* XXX */
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symfwmap[ELF_R_SYM(relp[ewi].r_info)] << 32 |
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ELF_R_TYPE(relp[ewi].r_info);
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#endif /* XXX */
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}
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}
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/*
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* write new tables to the file
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*/
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if (xwriteatoff(fd, shdrp, ehdr.e_shoff, shdrsize, fn) != shdrsize)
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goto bad;
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if (xwriteatoff(fd, symtabp, symtabshdr->sh_offset,
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symtabshdr->sh_size, fn) != symtabshdr->sh_size)
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goto bad;
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for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
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if (xwriteatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
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tmpl->size)
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goto bad;
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}
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for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
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if (xwriteatoff(fd, tmpl->mem, tmpl->file, tmpl->size, fn) !=
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tmpl->size)
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goto bad;
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}
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out:
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if (shdrp != NULL)
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free(shdrp);
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if (symtabp != NULL)
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free(symtabp);
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if (strtabp != NULL)
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free(strtabp);
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if (symfwmap != NULL)
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free(symfwmap);
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if (symrvmap != NULL)
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free(symrvmap);
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while ((tmpl = relalist) != NULL) {
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relalist = tmpl->next;
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if (tmpl->mem != NULL)
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free(tmpl->mem);
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free(tmpl);
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}
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while ((tmpl = rellist) != NULL) {
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rellist = tmpl->next;
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if (tmpl->mem != NULL)
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free(tmpl->mem);
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free(tmpl);
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}
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return (rv);
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bad:
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rv = 1;
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goto out;
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}
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#endif /* include this size of ELF */
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