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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * $FreeBSD: src/lib/libc/gen/nlist.c,v 1.12.2.1 2001/07/11 23:59:09 obrien Exp $
34 * $DragonFly: src/lib/libc/gen/nlist.c,v 1.6 2005/04/26 08:21:34 joerg Exp $
36 * @(#)nlist.c 8.1 (Berkeley) 6/4/93
39 #include "namespace.h"
40 #include <sys/param.h>
50 #include "un-namespace.h"
52 #define _NLIST_DO_AOUT
56 #include <machine/elf.h>
57 #include <elf-hints.h>
60 int __fdnlist(int, struct nlist
*);
61 int __aout_fdnlist(int, struct nlist
*);
62 int __elf_fdnlist(int, struct nlist
*);
65 nlist(const char *name
, struct nlist
*list
)
69 fd
= _open(name
, O_RDONLY
, 0);
72 n
= __fdnlist(fd
, list
);
77 static struct nlist_handlers
{
78 int (*fn
)(int fd
, struct nlist
*list
);
89 __fdnlist(int fd
, struct nlist
*list
)
94 for (i
= 0; i
< sizeof(nlist_fn
) / sizeof(nlist_fn
[0]); i
++) {
95 n
= (nlist_fn
[i
].fn
)(fd
, list
);
102 #define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
104 #ifdef _NLIST_DO_AOUT
106 __aout_fdnlist(int fd
, struct nlist
*list
)
108 struct nlist
*p
, *symtab
;
109 caddr_t strtab
, a_out_mmap
;
110 off_t stroff
, symoff
;
116 /* check that file is at least as large as struct exec! */
117 if ((_fstat(fd
, &st
) < 0) || (st
.st_size
< sizeof(struct exec
)))
120 /* Check for files too large to mmap. */
121 if (st
.st_size
> SIZE_T_MAX
) {
127 * Map the whole a.out file into our address space.
128 * We then find the string table withing this area.
129 * We do not just mmap the string table, as it probably
130 * does not start at a page boundary - we save ourselves a
131 * lot of nastiness by mmapping the whole file.
133 * This gives us an easy way to randomly access all the strings,
134 * without making the memory allocation permanent as with
135 * malloc/free (i.e., munmap will return it to the system).
137 a_out_mmap
= mmap(NULL
, (size_t)st
.st_size
, PROT_READ
, MAP_PRIVATE
, fd
, (off_t
)0);
138 if (a_out_mmap
== MAP_FAILED
)
141 exec
= (struct exec
*)a_out_mmap
;
142 if (N_BADMAG(*exec
)) {
143 munmap(a_out_mmap
, (size_t)st
.st_size
);
147 symoff
= N_SYMOFF(*exec
);
148 symsize
= exec
->a_syms
;
149 stroff
= symoff
+ symsize
;
151 /* find the string table in our mmapped area */
152 strtab
= a_out_mmap
+ stroff
;
153 symtab
= (struct nlist
*)(a_out_mmap
+ symoff
);
156 * clean out any left-over information for all valid entries.
157 * Type and value defined to be 0 if not found; historical
158 * versions cleared other and desc as well. Also figure out
159 * the largest string length so don't read any more of the
160 * string table than we have to.
162 * XXX clearing anything other than n_type and n_value violates
163 * the semantics given in the man page.
166 for (p
= list
; !ISLAST(p
); ++p
) {
174 while (symsize
> 0) {
177 symsize
-= sizeof(struct nlist
);
178 soff
= symtab
->n_un
.n_strx
;
181 if (soff
!= 0 && (symtab
->n_type
& N_STAB
) == 0)
182 for (p
= list
; !ISLAST(p
); p
++)
183 if (!strcmp(&strtab
[soff
], p
->n_un
.n_name
)) {
184 p
->n_value
= symtab
->n_value
;
185 p
->n_type
= symtab
->n_type
;
186 p
->n_desc
= symtab
->n_desc
;
187 p
->n_other
= symtab
->n_other
;
193 munmap(a_out_mmap
, (size_t)st
.st_size
);
199 static void elf_sym_to_nlist(struct nlist
*, Elf_Sym
*, Elf_Shdr
*, int);
202 * __elf_is_okay__ - Determine if ehdr really
203 * is ELF and valid for the target platform.
205 * WARNING: This is NOT a ELF ABI function and
206 * as such it's use should be restricted.
209 __elf_is_okay__(Elf_Ehdr
*ehdr
)
213 * We need to check magic, class size, endianess,
214 * and version before we look at the rest of the
215 * Elf_Ehdr structure. These few elements are
216 * represented in a machine independant fashion.
219 ehdr
->e_ident
[EI_CLASS
] == ELF_TARG_CLASS
&&
220 ehdr
->e_ident
[EI_DATA
] == ELF_TARG_DATA
&&
221 ehdr
->e_ident
[EI_VERSION
] == ELF_TARG_VER
) {
223 /* Now check the machine dependant header */
224 if (ehdr
->e_machine
== ELF_TARG_MACH
&&
225 ehdr
->e_version
== ELF_TARG_VER
)
232 __elf_fdnlist(int fd
, struct nlist
*list
)
235 Elf_Off symoff
= 0, symstroff
= 0;
236 Elf_Word symsize
= 0, symstrsize
= 0;
244 Elf_Shdr
*shdr
= NULL
;
249 /* Make sure obj is OK */
250 if (lseek(fd
, (off_t
)0, SEEK_SET
) == -1 ||
251 _read(fd
, &ehdr
, sizeof(Elf_Ehdr
)) != sizeof(Elf_Ehdr
) ||
252 !__elf_is_okay__(&ehdr
) ||
256 /* calculate section header table size */
257 shdr_size
= ehdr
.e_shentsize
* ehdr
.e_shnum
;
260 /* Make sure it's not too big to mmap */
261 if (shdr_size
> SIZE_T_MAX
) {
267 /* mmap section header table */
268 base
= mmap(NULL
, (size_t)shdr_size
, PROT_READ
, 0, 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
;
291 /* Check for files too large to mmap. */
292 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
)) {
345 struct nlist
*p_local
;
347 name
= strtab
+ s
->st_name
;
350 for (p_local
= list
; !ISLAST(p_local
); p_local
++) {
351 if ((p_local
->n_un
.n_name
[0] == '_' &&
352 strcmp(name
, p_local
->n_un
.n_name
+1) == 0)
353 || strcmp(name
, p_local
->n_un
.n_name
) == 0) {
354 elf_sym_to_nlist(p_local
, 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(struct nlist
*nl
, Elf_Sym
*s
, Elf_Shdr
*shdr
, int shnum
)
379 nl
->n_value
= s
->st_value
;
381 switch (s
->st_shndx
) {
387 nl
->n_type
= ELF_ST_TYPE(s
->st_info
) == STT_FILE
?
391 if (s
->st_shndx
>= shnum
)
394 Elf_Shdr
*sh
= shdr
+ s
->st_shndx
;
396 nl
->n_type
= sh
->sh_type
== SHT_PROGBITS
?
397 (sh
->sh_flags
& SHF_WRITE
? N_DATA
: N_TEXT
) :
398 (sh
->sh_type
== SHT_NOBITS
? N_BSS
: N_UNDF
);
403 if (ELF_ST_BIND(s
->st_info
) == STB_GLOBAL
||
404 ELF_ST_BIND(s
->st_info
) == STB_WEAK
)
407 #endif /* _NLIST_DO_ELF */