2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/cdefs.h>
33 __SCCSID("@(#)nlist.c 8.1 (Berkeley) 6/4/93");
34 __FBSDID("$FreeBSD$");
36 #include "namespace.h"
37 #include <sys/param.h>
41 #include <arpa/inet.h>
48 #include "un-namespace.h"
53 #include <machine/elf.h>
54 #include <elf-hints.h>
57 int __fdnlist(int, struct nlist *);
58 int __elf_fdnlist(int, struct nlist *);
59 int __elf_is_okay__(Elf_Ehdr *);
62 nlist(const char *name, struct nlist *list)
66 fd = _open(name, O_RDONLY | O_CLOEXEC, 0);
69 n = __fdnlist(fd, list);
74 static struct nlist_handlers {
75 int (*fn)(int fd, struct nlist *list);
83 __fdnlist(int fd, struct nlist *list)
88 for (i = 0; i < nitems(nlist_fn); i++) {
89 n = (nlist_fn[i].fn)(fd, list);
96 #define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
99 static void elf_sym_to_nlist(struct nlist *, Elf_Sym *, Elf_Shdr *, int);
102 * __elf_is_okay__ - Determine if ehdr really
103 * is ELF and valid for the target platform.
105 * WARNING: This is NOT an ELF ABI function and
106 * as such its use should be restricted.
109 __elf_is_okay__(Elf_Ehdr *ehdr)
113 * We need to check magic, class size, endianess,
114 * and version before we look at the rest of the
115 * Elf_Ehdr structure. These few elements are
116 * represented in a machine independant fashion.
119 ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS &&
120 ehdr->e_ident[EI_DATA] == ELF_TARG_DATA &&
121 ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) {
123 /* Now check the machine dependant header */
124 if (ehdr->e_machine == ELF_TARG_MACH &&
125 ehdr->e_version == ELF_TARG_VER)
132 __elf_fdnlist(int fd, struct nlist *list)
135 Elf_Off symoff = 0, symstroff = 0;
136 Elf_Size symsize = 0, symstrsize = 0;
144 Elf_Shdr *shdr = NULL;
149 /* Make sure obj is OK */
150 if (lseek(fd, (off_t)0, SEEK_SET) == -1 ||
151 _read(fd, &ehdr, sizeof(Elf_Ehdr)) != sizeof(Elf_Ehdr) ||
152 !__elf_is_okay__(&ehdr) ||
156 /* calculate section header table size */
157 shdr_size = ehdr.e_shentsize * ehdr.e_shnum;
159 /* Make sure it's not too big to mmap */
160 if (shdr_size > SIZE_T_MAX) {
165 /* mmap section header table */
166 base = mmap(NULL, (size_t)shdr_size, PROT_READ, MAP_PRIVATE, fd,
167 (off_t)ehdr.e_shoff);
168 if (base == MAP_FAILED)
170 shdr = (Elf_Shdr *)base;
173 * Find the symbol table entry and it's corresponding
174 * string table entry. Version 1.1 of the ABI states
175 * that there is only one symbol table but that this
176 * could change in the future.
178 for (i = 0; i < ehdr.e_shnum; i++) {
179 if (shdr[i].sh_type == SHT_SYMTAB) {
180 symoff = shdr[i].sh_offset;
181 symsize = shdr[i].sh_size;
182 symstroff = shdr[shdr[i].sh_link].sh_offset;
183 symstrsize = shdr[shdr[i].sh_link].sh_size;
188 /* Check for files too large to mmap. */
189 if (symstrsize > SIZE_T_MAX) {
194 * Map string table into our address space. This gives us
195 * an easy way to randomly access all the strings, without
196 * making the memory allocation permanent as with malloc/free
197 * (i.e., munmap will return it to the system).
199 base = mmap(NULL, (size_t)symstrsize, PROT_READ, MAP_PRIVATE, fd,
201 if (base == MAP_FAILED)
203 strtab = (char *)base;
206 * clean out any left-over information for all valid entries.
207 * Type and value defined to be 0 if not found; historical
208 * versions cleared other and desc as well. Also figure out
209 * the largest string length so don't read any more of the
210 * string table than we have to.
212 * XXX clearing anything other than n_type and n_value violates
213 * the semantics given in the man page.
216 for (p = list; !ISLAST(p); ++p) {
224 /* Don't process any further if object is stripped. */
228 if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) {
233 while (symsize > 0 && nent > 0) {
234 cc = MIN(symsize, sizeof(sbuf));
235 if (_read(fd, sbuf, cc) != cc)
238 for (s = sbuf; cc > 0 && nent > 0; ++s, cc -= sizeof(*s)) {
242 name = strtab + s->st_name;
245 for (p = list; !ISLAST(p); p++) {
246 if ((p->n_un.n_name[0] == '_' &&
247 strcmp(name, p->n_un.n_name+1) == 0)
248 || strcmp(name, p->n_un.n_name) == 0) {
249 elf_sym_to_nlist(p, s, shdr,
260 munmap(strtab, symstrsize);
262 munmap(shdr, shdr_size);
268 * Convert an Elf_Sym into an nlist structure. This fills in only the
269 * n_value and n_type members.
272 elf_sym_to_nlist(struct nlist *nl, Elf_Sym *s, Elf_Shdr *shdr, int shnum)
274 nl->n_value = s->st_value;
276 switch (s->st_shndx) {
282 nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ?
286 if (s->st_shndx >= shnum)
289 Elf_Shdr *sh = shdr + s->st_shndx;
291 nl->n_type = sh->sh_type == SHT_PROGBITS ?
292 (sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) :
293 (sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF);
298 if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
299 ELF_ST_BIND(s->st_info) == STB_WEAK)
302 #endif /* _NLIST_DO_ELF */