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 /* There is no a.out support on arm64 */
52 #define _NLIST_DO_AOUT
57 #include <machine/elf.h>
58 #include <elf-hints.h>
61 int __fdnlist(int, struct nlist *);
62 int __aout_fdnlist(int, struct nlist *);
63 int __elf_fdnlist(int, struct nlist *);
64 int __elf_is_okay__(Elf_Ehdr *);
67 nlist(const char *name, struct nlist *list)
71 fd = _open(name, O_RDONLY | O_CLOEXEC, 0);
74 n = __fdnlist(fd, list);
79 static struct nlist_handlers {
80 int (*fn)(int fd, struct nlist *list);
91 __fdnlist(int fd, struct nlist *list)
96 for (i = 0; i < sizeof(nlist_fn) / sizeof(nlist_fn[0]); i++) {
97 n = (nlist_fn[i].fn)(fd, list);
104 #define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
106 #ifdef _NLIST_DO_AOUT
108 __aout_fdnlist(int fd, struct nlist *list)
110 struct nlist *p, *symtab;
111 caddr_t strtab, a_out_mmap;
112 off_t stroff, symoff;
118 /* check that file is at least as large as struct exec! */
119 if ((_fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec)))
122 /* Check for files too large to mmap. */
123 if (st.st_size > SIZE_T_MAX) {
129 * Map the whole a.out file into our address space.
130 * We then find the string table withing this area.
131 * We do not just mmap the string table, as it probably
132 * does not start at a page boundary - we save ourselves a
133 * lot of nastiness by mmapping the whole file.
135 * This gives us an easy way to randomly access all the strings,
136 * without making the memory allocation permanent as with
137 * malloc/free (i.e., munmap will return it to the system).
139 a_out_mmap = mmap(NULL, (size_t)st.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0);
140 if (a_out_mmap == MAP_FAILED)
143 exec = (struct exec *)a_out_mmap;
144 if (N_BADMAG(*exec)) {
145 munmap(a_out_mmap, (size_t)st.st_size);
149 symoff = N_SYMOFF(*exec);
150 symsize = exec->a_syms;
151 stroff = symoff + symsize;
153 /* find the string table in our mmapped area */
154 strtab = a_out_mmap + stroff;
155 symtab = (struct nlist *)(a_out_mmap + symoff);
158 * clean out any left-over information for all valid entries.
159 * Type and value defined to be 0 if not found; historical
160 * versions cleared other and desc as well. Also figure out
161 * the largest string length so don't read any more of the
162 * string table than we have to.
164 * XXX clearing anything other than n_type and n_value violates
165 * the semantics given in the man page.
168 for (p = list; !ISLAST(p); ++p) {
176 while (symsize > 0) {
179 symsize-= sizeof(struct nlist);
180 soff = symtab->n_un.n_strx;
183 if (soff != 0 && (symtab->n_type & N_STAB) == 0)
184 for (p = list; !ISLAST(p); p++)
185 if (!strcmp(&strtab[soff], p->n_un.n_name)) {
186 p->n_value = symtab->n_value;
187 p->n_type = symtab->n_type;
188 p->n_desc = symtab->n_desc;
189 p->n_other = symtab->n_other;
195 munmap(a_out_mmap, (size_t)st.st_size);
201 static void elf_sym_to_nlist(struct nlist *, Elf_Sym *, Elf_Shdr *, int);
204 * __elf_is_okay__ - Determine if ehdr really
205 * is ELF and valid for the target platform.
207 * WARNING: This is NOT an ELF ABI function and
208 * as such its use should be restricted.
211 __elf_is_okay__(Elf_Ehdr *ehdr)
215 * We need to check magic, class size, endianess,
216 * and version before we look at the rest of the
217 * Elf_Ehdr structure. These few elements are
218 * represented in a machine independant fashion.
221 ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS &&
222 ehdr->e_ident[EI_DATA] == ELF_TARG_DATA &&
223 ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) {
225 /* Now check the machine dependant header */
226 if (ehdr->e_machine == ELF_TARG_MACH &&
227 ehdr->e_version == ELF_TARG_VER)
234 __elf_fdnlist(int fd, struct nlist *list)
237 Elf_Off symoff = 0, symstroff = 0;
238 Elf_Size symsize = 0, symstrsize = 0;
246 Elf_Shdr *shdr = NULL;
251 /* Make sure obj is OK */
252 if (lseek(fd, (off_t)0, SEEK_SET) == -1 ||
253 _read(fd, &ehdr, sizeof(Elf_Ehdr)) != sizeof(Elf_Ehdr) ||
254 !__elf_is_okay__(&ehdr) ||
258 /* calculate section header table size */
259 shdr_size = ehdr.e_shentsize * ehdr.e_shnum;
261 /* Make sure it's not too big to mmap */
262 if (shdr_size > SIZE_T_MAX) {
267 /* mmap section header table */
268 base = mmap(NULL, (size_t)shdr_size, PROT_READ, MAP_PRIVATE, fd,
269 (off_t)ehdr.e_shoff);
270 if (base == MAP_FAILED)
272 shdr = (Elf_Shdr *)base;
275 * Find the symbol table entry and it's corresponding
276 * string table entry. Version 1.1 of the ABI states
277 * that there is only one symbol table but that this
278 * could change in the future.
280 for (i = 0; i < ehdr.e_shnum; i++) {
281 if (shdr[i].sh_type == SHT_SYMTAB) {
282 symoff = shdr[i].sh_offset;
283 symsize = shdr[i].sh_size;
284 symstroff = shdr[shdr[i].sh_link].sh_offset;
285 symstrsize = shdr[shdr[i].sh_link].sh_size;
290 /* Check for files too large to mmap. */
291 if (symstrsize > SIZE_T_MAX) {
296 * Map string table into our address space. This gives us
297 * an easy way to randomly access all the strings, without
298 * making the memory allocation permanent as with malloc/free
299 * (i.e., munmap will return it to the system).
301 base = mmap(NULL, (size_t)symstrsize, PROT_READ, MAP_PRIVATE, fd,
303 if (base == MAP_FAILED)
305 strtab = (char *)base;
308 * clean out any left-over information for all valid entries.
309 * Type and value defined to be 0 if not found; historical
310 * versions cleared other and desc as well. Also figure out
311 * the largest string length so don't read any more of the
312 * string table than we have to.
314 * XXX clearing anything other than n_type and n_value violates
315 * the semantics given in the man page.
318 for (p = list; !ISLAST(p); ++p) {
326 /* Don't process any further if object is stripped. */
330 if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) {
335 while (symsize > 0 && nent > 0) {
336 cc = MIN(symsize, sizeof(sbuf));
337 if (_read(fd, sbuf, cc) != cc)
340 for (s = sbuf; cc > 0 && nent > 0; ++s, cc -= sizeof(*s)) {
344 name = strtab + s->st_name;
347 for (p = list; !ISLAST(p); p++) {
348 if ((p->n_un.n_name[0] == '_' &&
349 strcmp(name, p->n_un.n_name+1) == 0)
350 || strcmp(name, p->n_un.n_name) == 0) {
351 elf_sym_to_nlist(p, s, shdr,
362 munmap(strtab, symstrsize);
364 munmap(shdr, shdr_size);
370 * Convert an Elf_Sym into an nlist structure. This fills in only the
371 * n_value and n_type members.
374 elf_sym_to_nlist(struct nlist *nl, Elf_Sym *s, Elf_Shdr *shdr, int shnum)
376 nl->n_value = s->st_value;
378 switch (s->st_shndx) {
384 nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ?
388 if (s->st_shndx >= shnum)
391 Elf_Shdr *sh = shdr + s->st_shndx;
393 nl->n_type = sh->sh_type == SHT_PROGBITS ?
394 (sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) :
395 (sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF);
400 if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
401 ELF_ST_BIND(s->st_info) == STB_WEAK)
404 #endif /* _NLIST_DO_ELF */