1255033Semaste/* $NetBSD: symtab.c,v 1.2 2013/08/29 15:01:57 christos Exp $ */ 2254661Semaste 3254661Semaste/*- 4254661Semaste * Copyright (c) 2012 The NetBSD Foundation, Inc. 5254661Semaste * All rights reserved. 6254661Semaste * 7254661Semaste * This code is derived from software contributed to The NetBSD Foundation 8254661Semaste * by Christos Zoulas. 9254661Semaste * 10254661Semaste * Redistribution and use in source and binary forms, with or without 11254661Semaste * modification, are permitted provided that the following conditions 12254661Semaste * are met: 13254661Semaste * 1. Redistributions of source code must retain the above copyright 14254661Semaste * notice, this list of conditions and the following disclaimer. 15254661Semaste * 2. Redistributions in binary form must reproduce the above copyright 16254661Semaste * notice, this list of conditions and the following disclaimer in the 17254661Semaste * documentation and/or other materials provided with the distribution. 18254661Semaste * 19254661Semaste * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20254661Semaste * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21254661Semaste * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22254661Semaste * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23254661Semaste * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24254661Semaste * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25254661Semaste * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26254661Semaste * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27254661Semaste * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28254661Semaste * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29254661Semaste * POSSIBILITY OF SUCH DAMAGE. 30254661Semaste */ 31254661Semaste#include <sys/cdefs.h> 32255033Semaste__RCSID("$NetBSD: symtab.c,v 1.2 2013/08/29 15:01:57 christos Exp $"); 33254661Semaste 34254661Semaste#include <stdlib.h> 35254661Semaste#include <stdio.h> 36255033Semaste#include <string.h> 37254689Semaste#include <stdint.h> 38254661Semaste#include <err.h> 39254661Semaste#include <dlfcn.h> 40254661Semaste 41254661Semaste#include <libelf.h> 42254661Semaste#include <gelf.h> 43254661Semaste#ifndef ELF_ST_BIND 44254661Semaste#define ELF_ST_BIND(x) ((x) >> 4) 45254661Semaste#endif 46254661Semaste#ifndef ELF_ST_TYPE 47254661Semaste#define ELF_ST_TYPE(x) (((unsigned int)x) & 0xf) 48254661Semaste#endif 49254661Semaste 50254661Semaste 51254661Semaste#include "symtab.h" 52254661Semaste 53254661Semastestruct symbol { 54254661Semaste char *st_name; 55254661Semaste uintptr_t st_value; 56254661Semaste uintptr_t st_info; 57254661Semaste}; 58254661Semaste 59254661Semastestruct symtab { 60254661Semaste size_t nsymbols; 61254661Semaste struct symbol *symbols; 62254661Semaste}; 63254661Semaste 64254661Semastestatic int 65254661Semasteaddress_compare(const void *a, const void *b) 66254661Semaste{ 67254661Semaste const struct symbol *sa = a; 68254661Semaste const struct symbol *sb = b; 69254661Semaste return (int)(intmax_t)(sa->st_value - sb->st_value); 70254661Semaste} 71254661Semaste 72254661Semastevoid 73254661Semastesymtab_destroy(symtab_t *s) 74254661Semaste{ 75254661Semaste if (s == NULL) 76254661Semaste return; 77254661Semaste for (size_t i = 0; i < s->nsymbols; i++) 78254661Semaste free(s->symbols[i].st_name); 79254661Semaste free(s->symbols); 80254661Semaste free(s); 81254661Semaste} 82254661Semaste 83254661Semastesymtab_t * 84254661Semastesymtab_create(int fd, int bind, int type) 85254661Semaste{ 86254661Semaste Elf *elf; 87254661Semaste symtab_t *st; 88254661Semaste Elf_Scn *scn = NULL; 89254661Semaste 90254661Semaste if (elf_version(EV_CURRENT) == EV_NONE) { 91254661Semaste warnx("Elf Library is out of date."); 92254661Semaste return NULL; 93254661Semaste } 94254661Semaste 95254661Semaste elf = elf_begin(fd, ELF_C_READ, NULL); 96254661Semaste if (elf == NULL) { 97254661Semaste warnx("Error opening elf file: %s", elf_errmsg(elf_errno())); 98254661Semaste return NULL; 99254661Semaste } 100254661Semaste st = calloc(1, sizeof(*st)); 101254661Semaste if (st == NULL) { 102254661Semaste warnx("Error allocating symbol table"); 103254661Semaste elf_end(elf); 104254661Semaste return NULL; 105254661Semaste } 106254661Semaste 107254661Semaste while ((scn = elf_nextscn(elf, scn)) != NULL) { 108254661Semaste GElf_Shdr shdr; 109254661Semaste Elf_Data *edata; 110254661Semaste size_t ns; 111254661Semaste struct symbol *s; 112254661Semaste 113254661Semaste gelf_getshdr(scn, &shdr); 114254661Semaste if(shdr.sh_type != SHT_SYMTAB) 115254661Semaste continue; 116254661Semaste 117254661Semaste edata = elf_getdata(scn, NULL); 118254661Semaste ns = shdr.sh_size / shdr.sh_entsize; 119254661Semaste s = calloc(ns, sizeof(*s)); 120254661Semaste if (s == NULL) { 121254661Semaste warn("Cannot allocate %zu symbols", ns); 122254661Semaste goto out; 123254661Semaste } 124254661Semaste st->symbols = s; 125254661Semaste 126254661Semaste for (size_t i = 0; i < ns; i++) { 127254661Semaste GElf_Sym sym; 128254661Semaste gelf_getsym(edata, (int)i, &sym); 129254661Semaste 130254661Semaste if (bind != -1 && 131254661Semaste (unsigned)bind != ELF_ST_BIND(sym.st_info)) 132254661Semaste continue; 133254661Semaste 134254661Semaste if (type != -1 && 135254661Semaste (unsigned)type != ELF_ST_TYPE(sym.st_info)) 136254661Semaste continue; 137254661Semaste 138254661Semaste s->st_value = sym.st_value; 139254661Semaste s->st_info = sym.st_info; 140254661Semaste s->st_name = strdup( 141254661Semaste elf_strptr(elf, shdr.sh_link, sym.st_name)); 142254661Semaste if (s->st_name == NULL) 143254661Semaste goto out; 144254661Semaste s++; 145254661Semaste } 146254661Semaste st->nsymbols = s - st->symbols; 147254661Semaste if (st->nsymbols == 0) { 148254661Semaste warnx("No symbols found"); 149254661Semaste goto out; 150254661Semaste } 151254661Semaste qsort(st->symbols, st->nsymbols, sizeof(*st->symbols), 152254661Semaste address_compare); 153254661Semaste elf_end(elf); 154254661Semaste return st; 155254661Semaste } 156254661Semasteout: 157254661Semaste symtab_destroy(st); 158254661Semaste elf_end(elf); 159254661Semaste return NULL; 160254661Semaste} 161254661Semaste 162254661Semaste 163254661Semasteint 164254661Semastesymtab_find(const symtab_t *st, const void *p, Dl_info *dli) 165254661Semaste{ 166254661Semaste struct symbol *s = st->symbols; 167254661Semaste size_t ns = st->nsymbols; 168254661Semaste size_t hi = ns; 169254661Semaste size_t lo = 0; 170254661Semaste size_t mid = ns / 2; 171254661Semaste uintptr_t dd, sd, me = (uintptr_t)p; 172254661Semaste 173254661Semaste for (;;) { 174254661Semaste if (s[mid].st_value < me) 175254661Semaste lo = mid; 176254661Semaste else if (s[mid].st_value > me) 177254661Semaste hi = mid; 178254661Semaste else 179254661Semaste break; 180254661Semaste if (hi - lo == 1) { 181254661Semaste mid = lo; 182254661Semaste break; 183254661Semaste } 184254661Semaste mid = (hi + lo) / 2; 185254661Semaste } 186254661Semaste dd = me - (uintptr_t)dli->dli_saddr; 187254661Semaste sd = me - s[mid].st_value; 188254661Semaste if (dd > sd) { 189254661Semaste dli->dli_saddr = (void *)s[mid].st_value; 190254661Semaste dli->dli_sname = s[mid].st_name; 191254661Semaste } 192254661Semaste return 1; 193254661Semaste} 194