2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)nlist.c 8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
36 #include "namespace.h"
37 #include <sys/param.h>
41 #include <arpa/inet.h>
48 #include "un-namespace.h"
50 #define _NLIST_DO_AOUT
54 #include <machine/elf.h>
55 #include <elf-hints.h>
58 int __fdnlist(int, struct nlist *);
59 int __aout_fdnlist(int, struct nlist *);
60 int __elf_fdnlist(int, struct nlist *);
69 fd = _open(name, O_RDONLY | O_CLOEXEC, 0);
72 n = __fdnlist(fd, list);
77 static struct nlist_handlers {
78 int (*fn)(int fd, struct nlist *list);
95 for (i = 0; i < sizeof(nlist_fn) / sizeof(nlist_fn[0]); i++) {
96 n = (nlist_fn[i].fn)(fd, list);
103 #define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
105 #ifdef _NLIST_DO_AOUT
107 __aout_fdnlist(fd, list)
111 struct nlist *p, *symtab;
112 caddr_t strtab, a_out_mmap;
113 off_t stroff, symoff;
119 /* check that file is at least as large as struct exec! */
120 if ((_fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec)))
123 /* Check for files too large to mmap. */
124 if (st.st_size > SIZE_T_MAX) {
130 * Map the whole a.out file into our address space.
131 * We then find the string table withing this area.
132 * We do not just mmap the string table, as it probably
133 * does not start at a page boundary - we save ourselves a
134 * lot of nastiness by mmapping the whole file.
136 * This gives us an easy way to randomly access all the strings,
137 * without making the memory allocation permanent as with
138 * malloc/free (i.e., munmap will return it to the system).
140 a_out_mmap = mmap(NULL, (size_t)st.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0);
141 if (a_out_mmap == MAP_FAILED)
144 exec = (struct exec *)a_out_mmap;
145 if (N_BADMAG(*exec)) {
146 munmap(a_out_mmap, (size_t)st.st_size);
150 symoff = N_SYMOFF(*exec);
151 symsize = exec->a_syms;
152 stroff = symoff + symsize;
154 /* find the string table in our mmapped area */
155 strtab = a_out_mmap + stroff;
156 symtab = (struct nlist *)(a_out_mmap + symoff);
159 * clean out any left-over information for all valid entries.
160 * Type and value defined to be 0 if not found; historical
161 * versions cleared other and desc as well. Also figure out
162 * the largest string length so don't read any more of the
163 * string table than we have to.
165 * XXX clearing anything other than n_type and n_value violates
166 * the semantics given in the man page.
169 for (p = list; !ISLAST(p); ++p) {
177 while (symsize > 0) {
180 symsize-= sizeof(struct nlist);
181 soff = symtab->n_un.n_strx;
184 if (soff != 0 && (symtab->n_type & N_STAB) == 0)
185 for (p = list; !ISLAST(p); p++)
186 if (!strcmp(&strtab[soff], p->n_un.n_name)) {
187 p->n_value = symtab->n_value;
188 p->n_type = symtab->n_type;
189 p->n_desc = symtab->n_desc;
190 p->n_other = symtab->n_other;
196 munmap(a_out_mmap, (size_t)st.st_size);
202 static void elf_sym_to_nlist(struct nlist *, Elf_Sym *, Elf_Shdr *, int);
205 * __elf_is_okay__ - Determine if ehdr really
206 * is ELF and valid for the target platform.
208 * WARNING: This is NOT an ELF ABI function and
209 * as such its use should be restricted.
212 __elf_is_okay__(Elf_Ehdr *ehdr)
216 * We need to check magic, class size, endianess,
217 * and version before we look at the rest of the
218 * Elf_Ehdr structure. These few elements are
219 * represented in a machine independant fashion.
222 ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS &&
223 ehdr->e_ident[EI_DATA] == ELF_TARG_DATA &&
224 ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) {
226 /* Now check the machine dependant header */
227 if (ehdr->e_machine == ELF_TARG_MACH &&
228 ehdr->e_version == ELF_TARG_VER)
235 __elf_fdnlist(fd, list)
240 Elf_Off symoff = 0, symstroff = 0;
241 Elf_Size symsize = 0, symstrsize = 0;
249 Elf_Shdr *shdr = NULL;
254 /* Make sure obj is OK */
255 if (lseek(fd, (off_t)0, SEEK_SET) == -1 ||
256 _read(fd, &ehdr, sizeof(Elf_Ehdr)) != sizeof(Elf_Ehdr) ||
257 !__elf_is_okay__(&ehdr) ||
261 /* calculate section header table size */
262 shdr_size = ehdr.e_shentsize * ehdr.e_shnum;
264 /* Make sure it's not too big to mmap */
265 if (shdr_size > SIZE_T_MAX) {
270 /* mmap section header table */
271 base = mmap(NULL, (size_t)shdr_size, PROT_READ, 0, fd,
272 (off_t)ehdr.e_shoff);
273 if (base == MAP_FAILED)
275 shdr = (Elf_Shdr *)base;
278 * Find the symbol table entry and it's corresponding
279 * string table entry. Version 1.1 of the ABI states
280 * that there is only one symbol table but that this
281 * could change in the future.
283 for (i = 0; i < ehdr.e_shnum; i++) {
284 if (shdr[i].sh_type == SHT_SYMTAB) {
285 symoff = shdr[i].sh_offset;
286 symsize = shdr[i].sh_size;
287 symstroff = shdr[shdr[i].sh_link].sh_offset;
288 symstrsize = shdr[shdr[i].sh_link].sh_size;
293 /* Check for files too large to mmap. */
294 if (symstrsize > SIZE_T_MAX) {
299 * Map string table into our address space. This gives us
300 * an easy way to randomly access all the strings, without
301 * making the memory allocation permanent as with malloc/free
302 * (i.e., munmap will return it to the system).
304 base = mmap(NULL, (size_t)symstrsize, PROT_READ, 0, fd,
306 if (base == MAP_FAILED)
308 strtab = (char *)base;
311 * clean out any left-over information for all valid entries.
312 * Type and value defined to be 0 if not found; historical
313 * versions cleared other and desc as well. Also figure out
314 * the largest string length so don't read any more of the
315 * string table than we have to.
317 * XXX clearing anything other than n_type and n_value violates
318 * the semantics given in the man page.
321 for (p = list; !ISLAST(p); ++p) {
329 /* Don't process any further if object is stripped. */
333 if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) {
338 while (symsize > 0 && nent > 0) {
339 cc = MIN(symsize, sizeof(sbuf));
340 if (_read(fd, sbuf, cc) != cc)
343 for (s = sbuf; cc > 0 && nent > 0; ++s, cc -= sizeof(*s)) {
347 name = strtab + s->st_name;
350 for (p = list; !ISLAST(p); p++) {
351 if ((p->n_un.n_name[0] == '_' &&
352 strcmp(name, p->n_un.n_name+1) == 0)
353 || strcmp(name, p->n_un.n_name) == 0) {
354 elf_sym_to_nlist(p, s, shdr,
365 munmap(strtab, symstrsize);
367 munmap(shdr, shdr_size);
373 * Convert an Elf_Sym into an nlist structure. This fills in only the
374 * n_value and n_type members.
377 elf_sym_to_nlist(nl, s, shdr, shnum)
383 nl->n_value = s->st_value;
385 switch (s->st_shndx) {
391 nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ?
395 if (s->st_shndx >= shnum)
398 Elf_Shdr *sh = shdr + s->st_shndx;
400 nl->n_type = sh->sh_type == SHT_PROGBITS ?
401 (sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) :
402 (sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF);
407 if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
408 ELF_ST_BIND(s->st_info) == STB_WEAK)
411 #endif /* _NLIST_DO_ELF */