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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 $
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;
259 /* Make sure it's not too big to mmap */
260 if (shdr_size > SIZE_T_MAX) {
265 /* mmap section header table */
266 base = mmap(NULL, (size_t)shdr_size, PROT_READ, 0, fd,
267 (off_t)ehdr.e_shoff);
268 if (base == MAP_FAILED)
270 shdr = (Elf_Shdr *)base;
273 * Find the symbol table entry and it's corresponding
274 * string table entry. Version 1.1 of the ABI states
275 * that there is only one symbol table but that this
276 * could change in the future.
278 for (i = 0; i < ehdr.e_shnum; i++) {
279 if (shdr[i].sh_type == SHT_SYMTAB) {
280 symoff = shdr[i].sh_offset;
281 symsize = shdr[i].sh_size;
282 symstroff = shdr[shdr[i].sh_link].sh_offset;
283 symstrsize = shdr[shdr[i].sh_link].sh_size;
288 /* Check for files too large to mmap. */
289 if (symstrsize > SIZE_T_MAX) {
294 * Map string table into our address space. This gives us
295 * an easy way to randomly access all the strings, without
296 * making the memory allocation permanent as with malloc/free
297 * (i.e., munmap will return it to the system).
299 base = mmap(NULL, (size_t)symstrsize, PROT_READ, 0, fd,
301 if (base == MAP_FAILED)
303 strtab = (char *)base;
306 * clean out any left-over information for all valid entries.
307 * Type and value defined to be 0 if not found; historical
308 * versions cleared other and desc as well. Also figure out
309 * the largest string length so don't read any more of the
310 * string table than we have to.
312 * XXX clearing anything other than n_type and n_value violates
313 * the semantics given in the man page.
316 for (p = list; !ISLAST(p); ++p) {
324 /* Don't process any further if object is stripped. */
328 if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) {
333 while (symsize > 0 && nent > 0) {
334 cc = MIN(symsize, sizeof(sbuf));
335 if (_read(fd, sbuf, cc) != cc)
338 for (s = sbuf; cc > 0 && nent > 0; ++s, cc -= sizeof(*s)) {
340 struct nlist *p_local;
342 name = strtab + s->st_name;
345 for (p_local = list; !ISLAST(p_local); p_local++) {
346 if ((p_local->n_un.n_name[0] == '_' &&
347 strcmp(name, p_local->n_un.n_name+1) == 0)
348 || strcmp(name, p_local->n_un.n_name) == 0) {
349 elf_sym_to_nlist(p_local, s, shdr,
360 munmap(strtab, symstrsize);
362 munmap(shdr, shdr_size);
368 * Convert an Elf_Sym into an nlist structure. This fills in only the
369 * n_value and n_type members.
372 elf_sym_to_nlist(struct nlist *nl, Elf_Sym *s, Elf_Shdr *shdr, int shnum)
374 nl->n_value = s->st_value;
376 switch (s->st_shndx) {
382 nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ?
386 if (s->st_shndx >= shnum)
389 Elf_Shdr *sh = shdr + s->st_shndx;
391 nl->n_type = sh->sh_type == SHT_PROGBITS ?
392 (sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) :
393 (sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF);
398 if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
399 ELF_ST_BIND(s->st_info) == STB_WEAK)
402 #endif /* _NLIST_DO_ELF */