xref: /src/lib/libc/gen/nlist_elf32.c

/*	$NetBSD: nlist_elf32.c,v 1.2 1996/09/30 23:51:05 cgd Exp $	*/

/*
 * Copyright (c) 1996 Christopher G. Demetriou.  All rights reserved.
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)nlist.c	8.1 (Berkeley) 6/4/93";
#else
static char rcsid[] = "$NetBSD: nlist_elf32.c,v 1.2 1996/09/30 23:51:05 cgd Exp $";
#endif
#endif /* LIBC_SCCS and not lint */

/* If not included by nlist_elf64.c, ELFSIZE won't be defined. */
#ifndef ELFSIZE
#define	ELFSIZE		32
#endif

#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/file.h>

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <a.out.h>			/* for 'struct nlist' declaration */

#include "nlist_private.h"
#if defined(NLIST_ELF32) || defined(NLIST_ELF64)
#include <sys/exec_elf.h>
#endif

#if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \
    (defined(NLIST_ELF64) && (ELFSIZE == 64))

#define	CONCAT(x,y)	__CONCAT(x,y)
#define	ELFNAME(x)	CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
#define	ELFNAME2(x,y)	CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
#define	ELFNAMEEND(x)	CONCAT(x,CONCAT(_elf,ELFSIZE))
#define	ELFDEFNNAME(x)	CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))

int
ELFNAMEEND(__fdnlist)(fd, list)
	register int fd;
	register struct nlist *list;
{
	register struct nlist *p;
	register caddr_t strtab;
	register Elf32_Word symsize, symstrsize;
	register Elf32_Off symoff = 0, symstroff;
	register long nent, cc, i;
	Elf_Sym sbuf[1024];
	Elf_Sym *s;
	Elf_Ehdr ehdr;
	Elf_Shdr *shdr = NULL;
	Elf_Word shdr_size;
	struct stat st;

	/* Make sure obj is OK */
	if (lseek(fd, (off_t)0, SEEK_SET) == -1 ||
	    read(fd, &ehdr, sizeof(Elf_Ehdr)) != sizeof(Elf_Ehdr) ||
	    fstat(fd, &st) < 0)
		return (-1);

	if (bcmp(ehdr.e_ident, Elf_e_ident, Elf_e_siz))
		return (-1);

	switch (ehdr.e_machine) {
	ELFDEFNNAME(MACHDEP_ID_CASES)

	default:
		return (-1);
	}

	/* calculate section header table size */
	shdr_size = ehdr.e_shentsize * ehdr.e_shnum;

	/* Make sure it's not too big to mmap */
	if (shdr_size > SIZE_T_MAX) {
		errno = EFBIG;
		return (-1);
	}

	/* mmap section header table */
	shdr = (Elf_Shdr *)mmap(NULL, (size_t)shdr_size,
	    PROT_READ, 0, fd, ehdr.e_shoff);
	if (shdr == (Elf_Shdr *)-1)
		return (-1);

	/*
	 * Find the symbol table entry and it's corresponding
	 * string table entry.  Version 1.1 of the ABI states
	 * that there is only one symbol table but that this
	 * could change in the future.
	 */
	for (i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type == Elf_sht_symtab) {
			symoff = shdr[i].sh_offset;
			symsize = shdr[i].sh_size;
			symstroff = shdr[shdr[i].sh_link].sh_offset;
			symstrsize = shdr[shdr[i].sh_link].sh_size;
			break;
		}
	}

	/* Flush the section header table */
	munmap((caddr_t)shdr, shdr_size);

	/* Check for files too large to mmap. */
	/* XXX is this really possible? */
	if (symstrsize > SIZE_T_MAX) {
		errno = EFBIG;
		return (-1);
	}
	/*
	 * Map string table into our address space.  This gives us
	 * an easy way to randomly access all the strings, without
	 * making the memory allocation permanent as with malloc/free
	 * (i.e., munmap will return it to the system).
	 */
	strtab = mmap(NULL, (size_t)symstrsize, PROT_READ, 0, fd, symstroff);
	if (strtab == (char *)-1)
		return (-1);
	/*
	 * clean out any left-over information for all valid entries.
	 * Type and value defined to be 0 if not found; historical
	 * versions cleared other and desc as well.  Also figure out
	 * the largest string length so don't read any more of the
	 * string table than we have to.
	 *
	 * XXX clearing anything other than n_type and n_value violates
	 * the semantics given in the man page.
	 */
	nent = 0;
	for (p = list; !ISLAST(p); ++p) {
		p->n_type = 0;
		p->n_other = 0;
		p->n_desc = 0;
		p->n_value = 0;
		++nent;
	}

	/* Don't process any further if object is stripped. */
	/* ELFism - dunno if stripped by looking at header */
	if (symoff == 0)
		goto done;

	if (lseek(fd, symoff, SEEK_SET) == -1) {
		nent = -1;
		goto done;
	}

	while (symsize > 0) {
		cc = MIN(symsize, sizeof(sbuf));
		if (read(fd, sbuf, cc) != cc)
			break;
		symsize -= cc;
		for (s = sbuf; cc > 0; ++s, cc -= sizeof(*s)) {
			register int soff = s->st_name;

			if (soff == 0)
				continue;

			for (p = list; !ISLAST(p); p++) {
				char *nlistname;

				nlistname = p->n_un.n_name;
				if (*nlistname == '_')
					nlistname++;

				if (!strcmp(&strtab[soff], nlistname)) {
					p->n_value = s->st_value;

					switch(ELF_SYM_TYPE(s->st_info)) {
					case Elf_estt_notype:
						p->n_type = N_UNDF;
						break;
					case Elf_estt_object:
						p->n_type = N_DATA;
						break;
					case Elf_estt_func:
						p->n_type = N_TEXT;
						break;
					case Elf_estt_file:
						p->n_type = N_FN;
						break;
					}
					if (ELF_SYM_BIND(s->st_info) !=
					    Elf_estb_local)
						p->n_type |= N_EXT;
					p->n_desc = 0;
					p->n_other = 0;
					if (--nent <= 0)
						break;
				}
			}
		}
	}
done:
	munmap(strtab, symstrsize);

	return (nent);
}

#endif