193 lines
4.6 KiB
C
193 lines
4.6 KiB
C
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/* $NetBSD: symtab.c,v 1.1 2012/05/26 22:02:29 christos Exp $ */
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/*-
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* Copyright (c) 2012 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Christos Zoulas.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: symtab.c,v 1.1 2012/05/26 22:02:29 christos Exp $");
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <err.h>
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#include <dlfcn.h>
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#include <libelf.h>
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#include <gelf.h>
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#ifndef ELF_ST_BIND
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#define ELF_ST_BIND(x) ((x) >> 4)
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#endif
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#ifndef ELF_ST_TYPE
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#define ELF_ST_TYPE(x) (((unsigned int)x) & 0xf)
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#endif
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#include "symtab.h"
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struct symbol {
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char *st_name;
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uintptr_t st_value;
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uintptr_t st_info;
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};
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struct symtab {
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size_t nsymbols;
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struct symbol *symbols;
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};
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static int
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address_compare(const void *a, const void *b)
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{
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const struct symbol *sa = a;
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const struct symbol *sb = b;
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return (int)(intmax_t)(sa->st_value - sb->st_value);
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}
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void
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symtab_destroy(symtab_t *s)
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{
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if (s == NULL)
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return;
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for (size_t i = 0; i < s->nsymbols; i++)
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free(s->symbols[i].st_name);
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free(s->symbols);
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free(s);
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}
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symtab_t *
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symtab_create(int fd, int bind, int type)
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{
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Elf *elf;
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symtab_t *st;
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Elf_Scn *scn = NULL;
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if (elf_version(EV_CURRENT) == EV_NONE) {
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warnx("Elf Library is out of date.");
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return NULL;
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}
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elf = elf_begin(fd, ELF_C_READ, NULL);
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if (elf == NULL) {
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warnx("Error opening elf file: %s", elf_errmsg(elf_errno()));
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return NULL;
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}
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st = calloc(1, sizeof(*st));
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if (st == NULL) {
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warnx("Error allocating symbol table");
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elf_end(elf);
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return NULL;
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}
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while ((scn = elf_nextscn(elf, scn)) != NULL) {
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GElf_Shdr shdr;
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Elf_Data *edata;
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size_t ns;
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struct symbol *s;
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gelf_getshdr(scn, &shdr);
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if(shdr.sh_type != SHT_SYMTAB)
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continue;
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edata = elf_getdata(scn, NULL);
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ns = shdr.sh_size / shdr.sh_entsize;
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s = calloc(ns, sizeof(*s));
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if (s == NULL) {
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warn("Cannot allocate %zu symbols", ns);
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goto out;
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}
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st->symbols = s;
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for (size_t i = 0; i < ns; i++) {
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GElf_Sym sym;
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gelf_getsym(edata, (int)i, &sym);
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if (bind != -1 &&
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(unsigned)bind != ELF_ST_BIND(sym.st_info))
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continue;
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if (type != -1 &&
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(unsigned)type != ELF_ST_TYPE(sym.st_info))
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continue;
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s->st_value = sym.st_value;
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s->st_info = sym.st_info;
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s->st_name = strdup(
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elf_strptr(elf, shdr.sh_link, sym.st_name));
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if (s->st_name == NULL)
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goto out;
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s++;
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}
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st->nsymbols = s - st->symbols;
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if (st->nsymbols == 0) {
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warnx("No symbols found");
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goto out;
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}
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qsort(st->symbols, st->nsymbols, sizeof(*st->symbols),
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address_compare);
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elf_end(elf);
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return st;
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}
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out:
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symtab_destroy(st);
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elf_end(elf);
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return NULL;
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}
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int
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symtab_find(const symtab_t *st, const void *p, Dl_info *dli)
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{
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struct symbol *s = st->symbols;
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size_t ns = st->nsymbols;
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size_t hi = ns;
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size_t lo = 0;
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size_t mid = ns / 2;
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uintptr_t dd, sd, me = (uintptr_t)p;
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for (;;) {
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if (s[mid].st_value < me)
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lo = mid;
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else if (s[mid].st_value > me)
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hi = mid;
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else
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break;
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if (hi - lo == 1) {
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mid = lo;
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break;
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}
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mid = (hi + lo) / 2;
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}
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dd = me - (uintptr_t)dli->dli_saddr;
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sd = me - s[mid].st_value;
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if (dd > sd) {
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dli->dli_saddr = (void *)s[mid].st_value;
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dli->dli_sname = s[mid].st_name;
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}
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return 1;
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}
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