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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2007 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <libelf.h>
#include <gelf.h>
#include <errno.h>
/*
* symdef is a very simplified version of nm. It is used by upgrade and
* create_ramdisk in situations where we can't guarantee that nm will be around.
*
* Two arguments are expected: a binary and a symbol name. If the symbol is
* found in the name table of the binary, 0 is returned. If it is not found,
* 1 is returned. If an error occurs, a message is printed to stderr and -1
* is returned.
*/
static void
usage(void)
{
(void) fprintf(stderr, "USAGE: symdef file_name symbol\n");
}
int
main(int argc, char *argv[])
{
int fd = 0;
int rv = 1;
uint_t cnt, symcnt;
Elf *elfp = NULL;
Elf_Scn *scn = NULL;
size_t shstrndx;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
GElf_Sym sym;
Elf32_Word shndx;
Elf_Data *symdata, *shndxdata;
if (argc != 3) {
usage();
return (-1);
}
fd = open(argv[1], O_RDONLY);
if (fd == -1) {
(void) fprintf(stderr, "%s\n", strerror(errno));
rv = -1;
goto done;
}
if (elf_version(EV_CURRENT) == EV_NONE) {
(void) fprintf(stderr, "Elf library version out of date\n");
rv = -1;
goto done;
}
elfp = elf_begin(fd, ELF_C_READ, NULL);
if ((elfp == NULL) || (elf_kind(elfp) != ELF_K_ELF) ||
((gelf_getehdr(elfp, &ehdr)) == NULL) ||
(elf_getshstrndx(elfp, &shstrndx) == 0))
goto done;
while ((scn = elf_nextscn(elfp, scn)) != NULL) {
if ((gelf_getshdr(scn, &shdr) == NULL) ||
((shdr.sh_type != SHT_SYMTAB) &&
(shdr.sh_type != SHT_DYNSYM)) ||
((symdata = elf_getdata(scn, NULL)) == NULL))
continue;
symcnt = shdr.sh_size / shdr.sh_entsize;
shndxdata = NULL;
for (cnt = 0; cnt < symcnt; cnt++) {
if ((gelf_getsymshndx(symdata, shndxdata, cnt,
&sym, &shndx) != NULL) &&
(strcmp(argv[2], elf_strptr(elfp, shdr.sh_link,
sym.st_name)) == 0)) {
rv = 0;
goto done;
}
}
}
done:
if (elfp)
(void) elf_end(elfp);
if (fd != -1)
(void) close(fd);
return (rv);
}
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