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 51 #ifdef _NLIST_DO_ELF 52 #include <elf.h> 53 #endif 54 55 int __fdnlist __P((int, struct nlist *)); 56 int __aout_fdnlist __P((int, struct nlist *)); 57 int __elf_fdnlist __P((int, struct nlist *)); 58 59 int 60 nlist(name, list) 61 const char *name; 62 struct nlist *list; 63 { 64 int fd, n; 65 66 fd = open(name, O_RDONLY, 0); 67 if (fd < 0) 68 return (-1); 69 n = __fdnlist(fd, list); 70 (void)close(fd); 71 return (n); 72 } 73 74 static struct nlist_handlers { 75 int (*fn) __P((int fd, struct nlist *list)); 76 } nlist_fn[] = { 77 #ifdef _NLIST_DO_AOUT 78 { __aout_fdnlist }, 79 #endif 80 #ifdef _NLIST_DO_ELF 81 { __elf_fdnlist }, 82 #endif 83 }; 84 85 int 86 __fdnlist(fd, list) 87 register int fd; 88 register struct nlist *list; 89 { 90 int n = -1, i; 91 92 for (i = 0; i < sizeof(nlist_fn) / sizeof(nlist_fn[0]); i++) { 93 n = (nlist_fn[i].fn)(fd, list); 94 if (n != -1) 95 break; 96 } 97 return (n); 98 } 99 100 #define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0) 101 102 #ifdef _NLIST_DO_AOUT 103 int 104 __aout_fdnlist(fd, list) 105 register int fd; 106 register struct nlist *list; 107 { 108 register struct nlist *p, *symtab; 109 register caddr_t strtab, a_out_mmap; 110 register off_t stroff, symoff; 111 register u_long symsize; 112 register int nent; 113 struct exec * exec; 114 struct stat st; 115 116 /* check that file is at least as large as struct exec! */ 117 if ((fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec))) 118 return (-1); 119 120 /* Check for files too large to mmap. */ 121 if (st.st_size > SIZE_T_MAX) { 122 errno = EFBIG; 123 return (-1); 124 } 125 126 /* 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. 132 * 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). 136 */ 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) 139 return (-1); 140 141 exec = (struct exec *)a_out_mmap; 142 if (N_BADMAG(*exec)) { 143 munmap(a_out_mmap, (size_t)st.st_size); 144 return (-1); 145 } 146 147 symoff = N_SYMOFF(*exec); 148 symsize = exec->a_syms; 149 stroff = symoff + symsize; 150 151 /* find the string table in our mmapped area */ 152 strtab = a_out_mmap + stroff; 153 symtab = (struct nlist *)(a_out_mmap + symoff); 154 155 /* 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. 161 * 162 * XXX clearing anything other than n_type and n_value violates 163 * the semantics given in the man page. 164 */ 165 nent = 0; 166 for (p = list; !ISLAST(p); ++p) { 167 p->n_type = 0; 168 p->n_other = 0; 169 p->n_desc = 0; 170 p->n_value = 0; 171 ++nent; 172 } 173 174 while (symsize > 0) { 175 register int soff; 176 177 symsize-= sizeof(struct nlist); 178 soff = symtab->n_un.n_strx; 179 180 181 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; 188 if (--nent <= 0) 189 break; 190 } 191 symtab++; 192 } 193 munmap(a_out_mmap, (size_t)st.st_size); 194 return (nent); 195 } 196 #endif 197 198 #ifdef _NLIST_DO_ELF 199 /* 200 * __elf_is_okay__ - Determine if ehdr really 201 * is ELF and valid for the target platform. 202 * 203 * WARNING: This is NOT a ELF ABI function and 204 * as such it's use should be restricted. 205 */ 206 int 207 __elf_is_okay__(ehdr) 208 register Elf32_Ehdr *ehdr; 209 { 210 register int retval = 0; 211 /* 212 * We need to check magic, class size, endianess, 213 * and version before we look at the rest of the 214 * Elf32_Ehdr structure. These few elements are 215 * represented in a machine independant fashion. 216 */ 217 if (IS_ELF(*ehdr) && 218 ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS && 219 ehdr->e_ident[EI_DATA] == ELF_TARG_DATA && 220 ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) { 221 222 /* Now check the machine dependant header */ 223 if (ehdr->e_machine == ELF_TARG_MACH && 224 ehdr->e_version == ELF_TARG_VER) 225 retval = 1; 226 } 227 return retval; 228 } 229 230 int 231 __elf_fdnlist(fd, list) 232 register int fd; 233 register struct nlist *list; 234 { 235 register struct nlist *p; 236 register caddr_t strtab; 237 register Elf32_Off symoff = 0, symstroff = 0; 238 register Elf32_Word symsize = 0, symstrsize = 0; 239 register Elf32_Sword nent, cc, i; 240 Elf32_Sym sbuf[1024]; 241 Elf32_Sym *s; 242 Elf32_Ehdr ehdr; 243 Elf32_Shdr *shdr = NULL; 244 Elf32_Word shdr_size; 245 struct stat st; 246 247 /* Make sure obj is OK */ 248 if (lseek(fd, (off_t)0, SEEK_SET) == -1 || 249 read(fd, &ehdr, sizeof(Elf32_Ehdr)) != sizeof(Elf32_Ehdr) || 250 !__elf_is_okay__(&ehdr) || 251 fstat(fd, &st) < 0) 252 return (-1); 253 254 /* calculate section header table size */ 255 shdr_size = ehdr.e_shentsize * ehdr.e_shnum; 256 257 /* Make sure it's not too big to mmap */ 258 if (shdr_size > SIZE_T_MAX) { 259 errno = EFBIG; 260 return (-1); 261 } 262 263 /* mmap section header table */ 264 shdr = (Elf32_Shdr *)mmap(NULL, (size_t)shdr_size, 265 PROT_READ, 0, fd, (off_t) ehdr.e_shoff); 266 if (shdr == (Elf32_Shdr *)-1) 267 return (-1); 268 269 /* 270 * Find the symbol table entry and it's corresponding 271 * string table entry. Version 1.1 of the ABI states 272 * that there is only one symbol table but that this 273 * could change in the future. 274 */ 275 for (i = 0; i < ehdr.e_shnum; i++) { 276 if (shdr[i].sh_type == SHT_SYMTAB) { 277 symoff = shdr[i].sh_offset; 278 symsize = shdr[i].sh_size; 279 symstroff = shdr[shdr[i].sh_link].sh_offset; 280 symstrsize = shdr[shdr[i].sh_link].sh_size; 281 break; 282 } 283 } 284 285 /* Flush the section header table */ 286 munmap((caddr_t)shdr, shdr_size); 287 288 /* Check for files too large to mmap. */ 289 if (symstrsize > SIZE_T_MAX) { 290 errno = EFBIG; 291 return (-1); 292 } 293 /* 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). 298 */ 299 strtab = mmap(NULL, (size_t)symstrsize, PROT_READ, 0, fd, 300 (off_t) symstroff); 301 if (strtab == (char *)-1) 302 return (-1); 303 304 /* 305 * clean out any left-over information for all valid entries. 306 * Type and value defined to be 0 if not found; historical 307 * versions cleared other and desc as well. Also figure out 308 * the largest string length so don't read any more of the 309 * string table than we have to. 310 * 311 * XXX clearing anything other than n_type and n_value violates 312 * the semantics given in the man page. 313 */ 314 nent = 0; 315 for (p = list; !ISLAST(p); ++p) { 316 p->n_type = 0; 317 p->n_other = 0; 318 p->n_desc = 0; 319 p->n_value = 0; 320 ++nent; 321 } 322 323 /* Don't process any further if object is stripped. */ 324 /* ELFism - dunno if stripped by looking at header */ 325 if (symoff == 0) 326 goto done; 327 328 if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) { 329 nent = -1; 330 goto done; 331 } 332 333 while (symsize > 0) { 334 cc = MIN(symsize, sizeof(sbuf)); 335 if (read(fd, sbuf, cc) != cc) 336 break; 337 symsize -= cc; 338 for (s = sbuf; cc > 0; ++s, cc -= sizeof(*s)) { 339 register int soff = s->st_name; 340 341 if (soff == 0) 342 continue; 343 for (p = list; !ISLAST(p); p++) { 344 if ((p->n_un.n_name[0] == '_' && 345 !strcmp(&strtab[soff], p->n_un.n_name+1)) 346 || !strcmp(&strtab[soff], p->n_un.n_name)) { 347 p->n_value = s->st_value; 348 349 /* XXX - type conversion */ 350 /* is pretty rude. */ 351 switch(ELF32_ST_TYPE(s->st_info)) { 352 case STT_NOTYPE: 353 p->n_type = N_UNDF; 354 break; 355 case STT_OBJECT: 356 p->n_type = N_DATA; 357 break; 358 case STT_FUNC: 359 p->n_type = N_TEXT; 360 break; 361 case STT_FILE: 362 p->n_type = N_FN; 363 break; 364 } 365 if (ELF32_ST_BIND(s->st_info) == 366 STB_LOCAL) 367 p->n_type = N_EXT; 368 p->n_desc = 0; 369 p->n_other = 0; 370 if (--nent <= 0) 371 break; 372 } 373 } 374 } 375 } 376 done: 377 munmap(strtab, symstrsize); 378 379 return (nent); 380 } 381 #endif /* _NLIST_DO_ELF */ 382