1 /* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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. 20 * 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 31 * SUCH DAMAGE. 32 */ 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 static char sccsid[] = "@(#)nlist.c 8.1 (Berkeley) 6/4/93"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/param.h> 39 #include <sys/mman.h> 40 #include <sys/stat.h> 41 #include <sys/file.h> 42 43 #include <errno.h> 44 #include <a.out.h> 45 #include <stdio.h> 46 #include <string.h> 47 #include <unistd.h> 48 49 #define _NLIST_DO_AOUT 50 #define _NLIST_DO_ELF 51 52 #ifdef _NLIST_DO_ELF 53 #include <elf.h> 54 #endif 55 56 int __fdnlist __P((int, struct nlist *)); 57 int __aout_fdnlist __P((int, struct nlist *)); 58 int __elf_fdnlist __P((int, struct nlist *)); 59 60 int 61 nlist(name, list) 62 const char *name; 63 struct nlist *list; 64 { 65 int fd, n; 66 67 fd = open(name, O_RDONLY, 0); 68 if (fd < 0) 69 return (-1); 70 n = __fdnlist(fd, list); 71 (void)close(fd); 72 return (n); 73 } 74 75 static struct nlist_handlers { 76 int (*fn) __P((int fd, struct nlist *list)); 77 } nlist_fn[] = { 78 #ifdef _NLIST_DO_AOUT 79 { __aout_fdnlist }, 80 #endif 81 #ifdef _NLIST_DO_ELF 82 { __elf_fdnlist }, 83 #endif 84 }; 85 86 int 87 __fdnlist(fd, list) 88 register int fd; 89 register struct nlist *list; 90 { 91 int n = -1, i; 92 93 for (i = 0; i < sizeof(nlist_fn) / sizeof(nlist_fn[0]); i++) { 94 n = (nlist_fn[i].fn)(fd, list); 95 if (n != -1) 96 break; 97 } 98 return (n); 99 } 100 101 #define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0) 102 103 #ifdef _NLIST_DO_AOUT 104 int 105 __aout_fdnlist(fd, list) 106 register int fd; 107 register struct nlist *list; 108 { 109 register struct nlist *p, *symtab; 110 register caddr_t strtab, a_out_mmap; 111 register off_t stroff, symoff; 112 register u_long symsize; 113 register int nent; 114 struct exec * exec; 115 struct stat st; 116 117 /* check that file is at least as large as struct exec! */ 118 if ((fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec))) 119 return (-1); 120 121 /* Check for files too large to mmap. */ 122 if (st.st_size > SIZE_T_MAX) { 123 errno = EFBIG; 124 return (-1); 125 } 126 127 /* 128 * Map the whole a.out file into our address space. 129 * We then find the string table withing this area. 130 * We do not just mmap the string table, as it probably 131 * does not start at a page boundary - we save ourselves a 132 * lot of nastiness by mmapping the whole file. 133 * 134 * This gives us an easy way to randomly access all the strings, 135 * without making the memory allocation permanent as with 136 * malloc/free (i.e., munmap will return it to the system). 137 */ 138 a_out_mmap = mmap(NULL, (size_t)st.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0); 139 if (a_out_mmap == MAP_FAILED) 140 return (-1); 141 142 exec = (struct exec *)a_out_mmap; 143 if (N_BADMAG(*exec)) { 144 munmap(a_out_mmap, (size_t)st.st_size); 145 return (-1); 146 } 147 148 symoff = N_SYMOFF(*exec); 149 symsize = exec->a_syms; 150 stroff = symoff + symsize; 151 152 /* find the string table in our mmapped area */ 153 strtab = a_out_mmap + stroff; 154 symtab = (struct nlist *)(a_out_mmap + symoff); 155 156 /* 157 * clean out any left-over information for all valid entries. 158 * Type and value defined to be 0 if not found; historical 159 * versions cleared other and desc as well. Also figure out 160 * the largest string length so don't read any more of the 161 * string table than we have to. 162 * 163 * XXX clearing anything other than n_type and n_value violates 164 * the semantics given in the man page. 165 */ 166 nent = 0; 167 for (p = list; !ISLAST(p); ++p) { 168 p->n_type = 0; 169 p->n_other = 0; 170 p->n_desc = 0; 171 p->n_value = 0; 172 ++nent; 173 } 174 175 while (symsize > 0) { 176 register int soff; 177 178 symsize-= sizeof(struct nlist); 179 soff = symtab->n_un.n_strx; 180 181 182 if (soff != 0 && (symtab->n_type & N_STAB) == 0) 183 for (p = list; !ISLAST(p); p++) 184 if (!strcmp(&strtab[soff], p->n_un.n_name)) { 185 p->n_value = symtab->n_value; 186 p->n_type = symtab->n_type; 187 p->n_desc = symtab->n_desc; 188 p->n_other = symtab->n_other; 189 if (--nent <= 0) 190 break; 191 } 192 symtab++; 193 } 194 munmap(a_out_mmap, (size_t)st.st_size); 195 return (nent); 196 } 197 #endif 198 199 #ifdef _NLIST_DO_ELF 200 201 #if ELF_TARG_CLASS == ELFCLASS32 202 203 #define Elf(x) Elf32_##x 204 #define ELF(x) ELF32_##x 205 206 #else 207 208 #define Elf(x) Elf64_##x 209 #define ELF(x) ELF64_##x 210 211 #endif 212 213 /* 214 * __elf_is_okay__ - Determine if ehdr really 215 * is ELF and valid for the target platform. 216 * 217 * WARNING: This is NOT a ELF ABI function and 218 * as such it's use should be restricted. 219 */ 220 int 221 __elf_is_okay__(ehdr) 222 register Elf(Ehdr) *ehdr; 223 { 224 register int retval = 0; 225 /* 226 * We need to check magic, class size, endianess, 227 * and version before we look at the rest of the 228 * Elf(Ehdr) structure. These few elements are 229 * represented in a machine independant fashion. 230 */ 231 if (IS_ELF(*ehdr) && 232 ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS && 233 ehdr->e_ident[EI_DATA] == ELF_TARG_DATA && 234 ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) { 235 236 /* Now check the machine dependant header */ 237 if (ehdr->e_machine == ELF_TARG_MACH && 238 ehdr->e_version == ELF_TARG_VER) 239 retval = 1; 240 } 241 return retval; 242 } 243 244 int 245 __elf_fdnlist(fd, list) 246 register int fd; 247 register struct nlist *list; 248 { 249 register struct nlist *p; 250 register caddr_t strtab; 251 register Elf_Off symoff = 0, symstroff = 0; 252 register Elf_Word symsize = 0, symstrsize = 0; 253 register Elf_Sword nent, cc, i; 254 Elf_Sym sbuf[1024]; 255 Elf_Sym *s; 256 Elf_Ehdr ehdr; 257 Elf_Shdr *shdr = NULL; 258 Elf_Word shdr_size; 259 struct stat st; 260 261 /* Make sure obj is OK */ 262 if (lseek(fd, (off_t)0, SEEK_SET) == -1 || 263 read(fd, &ehdr, sizeof(Elf_Ehdr)) != sizeof(Elf_Ehdr) || 264 !__elf_is_okay__(&ehdr) || 265 fstat(fd, &st) < 0) 266 return (-1); 267 268 /* calculate section header table size */ 269 shdr_size = ehdr.e_shentsize * ehdr.e_shnum; 270 271 /* Make sure it's not too big to mmap */ 272 if (shdr_size > SIZE_T_MAX) { 273 errno = EFBIG; 274 return (-1); 275 } 276 277 /* mmap section header table */ 278 shdr = (Elf_Shdr *)mmap(NULL, (size_t)shdr_size, 279 PROT_READ, 0, fd, (off_t) ehdr.e_shoff); 280 if (shdr == (Elf_Shdr *)-1) 281 return (-1); 282 283 /* 284 * Find the symbol table entry and it's corresponding 285 * string table entry. Version 1.1 of the ABI states 286 * that there is only one symbol table but that this 287 * could change in the future. 288 */ 289 for (i = 0; i < ehdr.e_shnum; i++) { 290 if (shdr[i].sh_type == SHT_SYMTAB) { 291 symoff = shdr[i].sh_offset; 292 symsize = shdr[i].sh_size; 293 symstroff = shdr[shdr[i].sh_link].sh_offset; 294 symstrsize = shdr[shdr[i].sh_link].sh_size; 295 break; 296 } 297 } 298 299 /* Flush the section header table */ 300 munmap((caddr_t)shdr, shdr_size); 301 302 /* Check for files too large to mmap. */ 303 if (symstrsize > SIZE_T_MAX) { 304 errno = EFBIG; 305 return (-1); 306 } 307 /* 308 * Map string table into our address space. This gives us 309 * an easy way to randomly access all the strings, without 310 * making the memory allocation permanent as with malloc/free 311 * (i.e., munmap will return it to the system). 312 */ 313 strtab = mmap(NULL, (size_t)symstrsize, PROT_READ, 0, fd, 314 (off_t) symstroff); 315 if (strtab == (char *)-1) 316 return (-1); 317 318 /* 319 * clean out any left-over information for all valid entries. 320 * Type and value defined to be 0 if not found; historical 321 * versions cleared other and desc as well. Also figure out 322 * the largest string length so don't read any more of the 323 * string table than we have to. 324 * 325 * XXX clearing anything other than n_type and n_value violates 326 * the semantics given in the man page. 327 */ 328 nent = 0; 329 for (p = list; !ISLAST(p); ++p) { 330 p->n_type = 0; 331 p->n_other = 0; 332 p->n_desc = 0; 333 p->n_value = 0; 334 ++nent; 335 } 336 337 /* Don't process any further if object is stripped. */ 338 /* ELFism - dunno if stripped by looking at header */ 339 if (symoff == 0) 340 goto done; 341 342 if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) { 343 nent = -1; 344 goto done; 345 } 346 347 while (symsize > 0) { 348 cc = MIN(symsize, sizeof(sbuf)); 349 if (read(fd, sbuf, cc) != cc) 350 break; 351 symsize -= cc; 352 for (s = sbuf; cc > 0; ++s, cc -= sizeof(*s)) { 353 register int soff = s->st_name; 354 355 if (soff == 0) 356 continue; 357 for (p = list; !ISLAST(p); p++) { 358 if ((p->n_un.n_name[0] == '_' && 359 !strcmp(&strtab[soff], p->n_un.n_name+1)) 360 || !strcmp(&strtab[soff], p->n_un.n_name)) { 361 p->n_value = s->st_value; 362 363 /* XXX - type conversion */ 364 /* is pretty rude. */ 365 switch(ELF(ST_TYPE)(s->st_info)) { 366 case STT_NOTYPE: 367 p->n_type = N_UNDF; 368 break; 369 case STT_OBJECT: 370 p->n_type = N_DATA; 371 break; 372 case STT_FUNC: 373 p->n_type = N_TEXT; 374 break; 375 case STT_FILE: 376 p->n_type = N_FN; 377 break; 378 } 379 if (ELF(ST_BIND)(s->st_info) == 380 STB_LOCAL) 381 p->n_type = N_EXT; 382 p->n_desc = 0; 383 p->n_other = 0; 384 if (--nent <= 0) 385 break; 386 } 387 } 388 } 389 } 390 done: 391 munmap(strtab, symstrsize); 392 393 return (nent); 394 } 395 #endif /* _NLIST_DO_ELF */ 396