2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
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13 * 3. All advertising materials mentioning features or use of this software
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15 * This product includes software developed by the University of
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17 * 4. Neither the name of the University nor the names of its contributors
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33 * $FreeBSD: src/lib/libc/gen/nlist.c,v 1.12.2.1 2001/07/11 23:59:09 obrien Exp $
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static char sccsid[] = "@(#)nlist.c 8.1 (Berkeley) 6/4/93";
38 #endif /* LIBC_SCCS and not lint */
40 #include <sys/param.h>
51 #define _NLIST_DO_AOUT
55 #include <machine/elf.h>
56 #include <elf-hints.h>
59 int __fdnlist __P((int, struct nlist *));
60 int __aout_fdnlist __P((int, struct nlist *));
61 int __elf_fdnlist __P((int, struct nlist *));
70 fd = _open(name, O_RDONLY, 0);
73 n = __fdnlist(fd, list);
78 static struct nlist_handlers {
79 int (*fn) __P((int fd, struct nlist *list));
92 register 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(fd, list)
110 register struct nlist *list;
112 register struct nlist *p, *symtab;
113 register caddr_t strtab, a_out_mmap;
114 register off_t stroff, symoff;
115 register u_long symsize;
120 /* check that file is at least as large as struct exec! */
121 if ((fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec)))
124 /* Check for files too large to mmap. */
125 if (st.st_size > SIZE_T_MAX) {
131 * Map the whole a.out file into our address space.
132 * We then find the string table withing this area.
133 * We do not just mmap the string table, as it probably
134 * does not start at a page boundary - we save ourselves a
135 * lot of nastiness by mmapping the whole file.
137 * This gives us an easy way to randomly access all the strings,
138 * without making the memory allocation permanent as with
139 * malloc/free (i.e., munmap will return it to the system).
141 a_out_mmap = mmap(NULL, (size_t)st.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0);
142 if (a_out_mmap == MAP_FAILED)
145 exec = (struct exec *)a_out_mmap;
146 if (N_BADMAG(*exec)) {
147 munmap(a_out_mmap, (size_t)st.st_size);
151 symoff = N_SYMOFF(*exec);
152 symsize = exec->a_syms;
153 stroff = symoff + symsize;
155 /* find the string table in our mmapped area */
156 strtab = a_out_mmap + stroff;
157 symtab = (struct nlist *)(a_out_mmap + symoff);
160 * clean out any left-over information for all valid entries.
161 * Type and value defined to be 0 if not found; historical
162 * versions cleared other and desc as well. Also figure out
163 * the largest string length so don't read any more of the
164 * string table than we have to.
166 * XXX clearing anything other than n_type and n_value violates
167 * the semantics given in the man page.
170 for (p = list; !ISLAST(p); ++p) {
178 while (symsize > 0) {
181 symsize-= sizeof(struct nlist);
182 soff = symtab->n_un.n_strx;
185 if (soff != 0 && (symtab->n_type & N_STAB) == 0)
186 for (p = list; !ISLAST(p); p++)
187 if (!strcmp(&strtab[soff], p->n_un.n_name)) {
188 p->n_value = symtab->n_value;
189 p->n_type = symtab->n_type;
190 p->n_desc = symtab->n_desc;
191 p->n_other = symtab->n_other;
197 munmap(a_out_mmap, (size_t)st.st_size);
203 static void elf_sym_to_nlist __P((struct nlist *, Elf_Sym *, Elf_Shdr *, int));
206 * __elf_is_okay__ - Determine if ehdr really
207 * is ELF and valid for the target platform.
209 * WARNING: This is NOT a ELF ABI function and
210 * as such it's use should be restricted.
213 __elf_is_okay__(ehdr)
214 register Elf_Ehdr *ehdr;
216 register int retval = 0;
218 * We need to check magic, class size, endianess,
219 * and version before we look at the rest of the
220 * Elf_Ehdr structure. These few elements are
221 * represented in a machine independant fashion.
224 ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS &&
225 ehdr->e_ident[EI_DATA] == ELF_TARG_DATA &&
226 ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) {
228 /* Now check the machine dependant header */
229 if (ehdr->e_machine == ELF_TARG_MACH &&
230 ehdr->e_version == ELF_TARG_VER)
237 __elf_fdnlist(fd, list)
239 register struct nlist *list;
241 register struct nlist *p;
242 register Elf_Off symoff = 0, symstroff = 0;
243 register Elf_Word symsize = 0, symstrsize = 0;
244 register Elf_Sword cc, i;
251 Elf_Shdr *shdr = NULL;
257 /* Make sure obj is OK */
258 if (lseek(fd, (off_t)0, SEEK_SET) == -1 ||
259 _read(fd, &ehdr, sizeof(Elf_Ehdr)) != sizeof(Elf_Ehdr) ||
260 !__elf_is_okay__(&ehdr) ||
264 /* calculate section header table size */
265 shdr_size = ehdr.e_shentsize * ehdr.e_shnum;
267 /* Make sure it's not too big to mmap */
268 if (shdr_size > SIZE_T_MAX) {
273 /* mmap section header table */
274 base = mmap(NULL, (size_t)shdr_size, PROT_READ, 0, fd,
275 (off_t)ehdr.e_shoff);
276 if (base == MAP_FAILED)
278 shdr = (Elf_Shdr *)base;
281 * Find the symbol table entry and it's corresponding
282 * string table entry. Version 1.1 of the ABI states
283 * that there is only one symbol table but that this
284 * could change in the future.
286 for (i = 0; i < ehdr.e_shnum; i++) {
287 if (shdr[i].sh_type == SHT_SYMTAB) {
288 symoff = shdr[i].sh_offset;
289 symsize = shdr[i].sh_size;
290 symstroff = shdr[shdr[i].sh_link].sh_offset;
291 symstrsize = shdr[shdr[i].sh_link].sh_size;
296 /* Check for files too large to mmap. */
297 if (symstrsize > SIZE_T_MAX) {
302 * Map string table into our address space. This gives us
303 * an easy way to randomly access all the strings, without
304 * making the memory allocation permanent as with malloc/free
305 * (i.e., munmap will return it to the system).
307 base = mmap(NULL, (size_t)symstrsize, PROT_READ, 0, fd,
309 if (base == MAP_FAILED)
311 strtab = (char *)base;
314 * clean out any left-over information for all valid entries.
315 * Type and value defined to be 0 if not found; historical
316 * versions cleared other and desc as well. Also figure out
317 * the largest string length so don't read any more of the
318 * string table than we have to.
320 * XXX clearing anything other than n_type and n_value violates
321 * the semantics given in the man page.
324 for (p = list; !ISLAST(p); ++p) {
332 /* Don't process any further if object is stripped. */
336 if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) {
341 while (symsize > 0 && nent > 0) {
342 cc = MIN(symsize, sizeof(sbuf));
343 if (_read(fd, sbuf, cc) != cc)
346 for (s = sbuf; cc > 0 && nent > 0; ++s, cc -= sizeof(*s)) {
350 name = strtab + s->st_name;
353 for (p = list; !ISLAST(p); p++) {
354 if ((p->n_un.n_name[0] == '_' &&
355 strcmp(name, p->n_un.n_name+1) == 0)
356 || strcmp(name, p->n_un.n_name) == 0) {
357 elf_sym_to_nlist(p, s, shdr,
368 munmap(strtab, symstrsize);
370 munmap(shdr, shdr_size);
376 * Convert an Elf_Sym into an nlist structure. This fills in only the
377 * n_value and n_type members.
380 elf_sym_to_nlist(nl, s, shdr, shnum)
386 nl->n_value = s->st_value;
388 switch (s->st_shndx) {
394 nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ?
398 if (s->st_shndx >= shnum)
401 Elf_Shdr *sh = shdr + s->st_shndx;
403 nl->n_type = sh->sh_type == SHT_PROGBITS ?
404 (sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) :
405 (sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF);
410 if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
411 ELF_ST_BIND(s->st_info) == STB_WEAK)
414 #endif /* _NLIST_DO_ELF */