1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1993 Paul Kranenburg 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Paul Kranenburg. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/param.h> 37 #include <sys/wait.h> 38 39 #include <machine/elf.h> 40 41 #include <arpa/inet.h> 42 43 #include <dlfcn.h> 44 #include <err.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <gelf.h> 48 #include <libelf.h> 49 #include <stdbool.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 55 /* 56 * 32-bit ELF data structures can only be used if the system header[s] declare 57 * them. There is no official macro for determining whether they are declared, 58 * so check for the existence of one of the 32-macros defined in elf(5). 59 */ 60 #ifdef ELF32_R_TYPE 61 #define ELF32_SUPPORTED 62 #endif 63 64 #define LDD_SETENV(name, value, overwrite) do { \ 65 setenv("LD_" name, value, overwrite); \ 66 setenv("LD_32_" name, value, overwrite); \ 67 } while (0) 68 69 #define LDD_UNSETENV(name) do { \ 70 unsetenv("LD_" name); \ 71 unsetenv("LD_32_" name); \ 72 } while (0) 73 74 static int is_executable(const char *fname, int fd, int *is_shlib, 75 int *type); 76 static void usage(void); 77 78 #define TYPE_UNKNOWN 0 79 #define TYPE_ELF 1 /* Architecture default */ 80 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 81 #define TYPE_ELF32 2 /* Explicit 32 bits on architectures >32 bits */ 82 83 #define _PATH_LDD32 "/usr/bin/ldd32" 84 85 static int 86 execldd32(char *file, char *fmt1, char *fmt2, int aflag) 87 { 88 char *argv[9]; 89 int i, rval, status; 90 91 LDD_UNSETENV("TRACE_LOADED_OBJECTS"); 92 rval = 0; 93 i = 0; 94 argv[i++] = strdup(_PATH_LDD32); 95 if (aflag) 96 argv[i++] = strdup("-a"); 97 if (fmt1 != NULL) { 98 argv[i++] = strdup("-f"); 99 argv[i++] = strdup(fmt1); 100 } 101 if (fmt2 != NULL) { 102 argv[i++] = strdup("-f"); 103 argv[i++] = strdup(fmt2); 104 } 105 argv[i++] = strdup(file); 106 argv[i++] = NULL; 107 108 switch (fork()) { 109 case -1: 110 err(1, "fork"); 111 break; 112 case 0: 113 execv(_PATH_LDD32, argv); 114 warn("%s", _PATH_LDD32); 115 _exit(127); 116 break; 117 default: 118 if (wait(&status) < 0) 119 rval = 1; 120 else if (WIFSIGNALED(status)) 121 rval = 1; 122 else if (WIFEXITED(status) && WEXITSTATUS(status) != 0) 123 rval = 1; 124 break; 125 } 126 while (i--) 127 free(argv[i]); 128 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 129 return (rval); 130 } 131 #endif 132 133 int 134 main(int argc, char *argv[]) 135 { 136 char *fmt1, *fmt2; 137 int rval, c, aflag; 138 139 aflag = 0; 140 fmt1 = fmt2 = NULL; 141 142 while ((c = getopt(argc, argv, "af:")) != -1) { 143 switch (c) { 144 case 'a': 145 aflag++; 146 break; 147 case 'f': 148 if (fmt1 != NULL) { 149 if (fmt2 != NULL) 150 errx(1, "too many formats"); 151 fmt2 = optarg; 152 } else 153 fmt1 = optarg; 154 break; 155 default: 156 usage(); 157 /* NOTREACHED */ 158 } 159 } 160 argc -= optind; 161 argv += optind; 162 163 if (argc <= 0) { 164 usage(); 165 /* NOTREACHED */ 166 } 167 168 rval = 0; 169 for (; argc > 0; argc--, argv++) { 170 int fd, status, is_shlib, rv, type; 171 172 if ((fd = open(*argv, O_RDONLY, 0)) < 0) { 173 warn("%s", *argv); 174 rval |= 1; 175 continue; 176 } 177 rv = is_executable(*argv, fd, &is_shlib, &type); 178 close(fd); 179 if (rv == 0) { 180 rval |= 1; 181 continue; 182 } 183 184 switch (type) { 185 case TYPE_ELF: 186 break; 187 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 188 case TYPE_ELF32: 189 rval |= execldd32(*argv, fmt1, fmt2, aflag); 190 continue; 191 #endif 192 case TYPE_UNKNOWN: 193 default: 194 /* 195 * This shouldn't happen unless is_executable() 196 * is broken. 197 */ 198 errx(EDOOFUS, "unknown executable type"); 199 } 200 201 /* ld.so magic */ 202 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 203 if (fmt1 != NULL) 204 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT1", fmt1, 1); 205 if (fmt2 != NULL) 206 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT2", fmt2, 1); 207 208 LDD_SETENV("TRACE_LOADED_OBJECTS_PROGNAME", *argv, 1); 209 if (aflag) 210 LDD_SETENV("TRACE_LOADED_OBJECTS_ALL", "1", 1); 211 else if (fmt1 == NULL && fmt2 == NULL) 212 /* Default formats */ 213 printf("%s:\n", *argv); 214 fflush(stdout); 215 216 switch (fork()) { 217 case -1: 218 err(1, "fork"); 219 break; 220 default: 221 if (wait(&status) < 0) { 222 warn("wait"); 223 rval |= 1; 224 } else if (WIFSIGNALED(status)) { 225 fprintf(stderr, "%s: signal %d\n", *argv, 226 WTERMSIG(status)); 227 rval |= 1; 228 } else if (WIFEXITED(status) && 229 WEXITSTATUS(status) != 0) { 230 fprintf(stderr, "%s: exit status %d\n", *argv, 231 WEXITSTATUS(status)); 232 rval |= 1; 233 } 234 break; 235 case 0: 236 if (is_shlib == 0) { 237 execl(*argv, *argv, (char *)NULL); 238 warn("%s", *argv); 239 } else { 240 dlopen(*argv, RTLD_TRACE); 241 warnx("%s: %s", *argv, dlerror()); 242 } 243 _exit(1); 244 } 245 } 246 247 return rval; 248 } 249 250 static void 251 usage(void) 252 { 253 254 fprintf(stderr, "usage: ldd [-a] [-f format] program ...\n"); 255 exit(1); 256 } 257 258 static bool 259 has_freebsd_abi_tag(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, 260 size_t len) 261 { 262 Elf_Data dst, src; 263 const Elf_Note *note; 264 char *buf; 265 const char *name; 266 void *copy; 267 size_t namesz, descsz; 268 bool has_abi_tag; 269 270 buf = elf_rawfile(elf, NULL); 271 if (buf == NULL) { 272 warnx("%s: %s", fname, elf_errmsg(0)); 273 return (false); 274 } 275 276 memset(&src, 0, sizeof(src)); 277 src.d_buf = buf + offset; 278 src.d_size = len; 279 src.d_type = ELF_T_NOTE; 280 src.d_version = EV_CURRENT; 281 282 memset(&dst, 0, sizeof(dst)); 283 dst.d_buf = copy = malloc(len); 284 dst.d_size = len; 285 dst.d_type = ELF_T_NOTE; 286 dst.d_version = EV_CURRENT; 287 288 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 289 warnx("%s: failed to parse notes: %s", fname, elf_errmsg(0)); 290 free(copy); 291 return (false); 292 } 293 294 buf = copy; 295 has_abi_tag = false; 296 for (;;) { 297 if (len < sizeof(*note)) 298 break; 299 300 note = (const void *)buf; 301 buf += sizeof(*note); 302 len -= sizeof(*note); 303 304 namesz = roundup2(note->n_namesz, sizeof(uint32_t)); 305 descsz = roundup2(note->n_descsz, sizeof(uint32_t)); 306 if (len < namesz + descsz) 307 break; 308 309 name = buf; 310 if (note->n_namesz == sizeof(ELF_NOTE_FREEBSD) && 311 strncmp(name, ELF_NOTE_FREEBSD, note->n_namesz) == 0 && 312 note->n_type == NT_FREEBSD_ABI_TAG && 313 note->n_descsz == sizeof(uint32_t)) { 314 has_abi_tag = true; 315 break; 316 } 317 318 buf += namesz + descsz; 319 len -= namesz + descsz; 320 } 321 322 free(copy); 323 return (has_abi_tag); 324 } 325 326 static bool 327 is_pie(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, size_t len) 328 { 329 Elf_Data dst, src; 330 char *buf; 331 void *copy; 332 const GElf_Dyn *dyn; 333 size_t dynsize; 334 u_int count, i; 335 bool pie; 336 337 buf = elf_rawfile(elf, NULL); 338 if (buf == NULL) { 339 warnx("%s: %s", fname, elf_errmsg(0)); 340 return (false); 341 } 342 343 dynsize = gelf_fsize(elf, ELF_T_DYN, 1, EV_CURRENT); 344 if (dynsize == 0) { 345 warnx("%s: %s", fname, elf_errmsg(0)); 346 return (false); 347 } 348 count = len / dynsize; 349 350 memset(&src, 0, sizeof(src)); 351 src.d_buf = buf + offset; 352 src.d_size = len; 353 src.d_type = ELF_T_DYN; 354 src.d_version = EV_CURRENT; 355 356 memset(&dst, 0, sizeof(dst)); 357 dst.d_buf = copy = malloc(count * sizeof(*dyn)); 358 dst.d_size = count * sizeof(*dyn); 359 dst.d_type = ELF_T_DYN; 360 dst.d_version = EV_CURRENT; 361 362 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 363 warnx("%s: failed to parse .dynamic: %s", fname, elf_errmsg(0)); 364 free(copy); 365 return (false); 366 } 367 368 dyn = copy; 369 pie = false; 370 for (i = 0; i < count; i++) { 371 if (dyn[i].d_tag != DT_FLAGS_1) 372 continue; 373 374 pie = (dyn[i].d_un.d_val & DF_1_PIE) != 0; 375 break; 376 } 377 378 free(copy); 379 return (pie); 380 } 381 382 static int 383 is_executable(const char *fname, int fd, int *is_shlib, int *type) 384 { 385 Elf *elf; 386 GElf_Ehdr ehdr; 387 GElf_Phdr phdr; 388 bool dynamic, freebsd, pie; 389 int i; 390 391 *is_shlib = 0; 392 *type = TYPE_UNKNOWN; 393 dynamic = false; 394 freebsd = false; 395 pie = false; 396 397 if (elf_version(EV_CURRENT) == EV_NONE) { 398 warnx("unsupported libelf"); 399 return (0); 400 } 401 elf = elf_begin(fd, ELF_C_READ, NULL); 402 if (elf == NULL) { 403 warnx("%s: %s", fname, elf_errmsg(0)); 404 return (0); 405 } 406 if (elf_kind(elf) != ELF_K_ELF) { 407 elf_end(elf); 408 warnx("%s: not a dynamic ELF executable", fname); 409 return (0); 410 } 411 if (gelf_getehdr(elf, &ehdr) == NULL) { 412 warnx("%s: %s", fname, elf_errmsg(0)); 413 elf_end(elf); 414 return (0); 415 } 416 417 *type = TYPE_ELF; 418 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 419 if (gelf_getclass(elf) == ELFCLASS32) { 420 *type = TYPE_ELF32; 421 } 422 #endif 423 424 freebsd = ehdr.e_ident[EI_OSABI] == ELFOSABI_FREEBSD; 425 for (i = 0; i < ehdr.e_phnum; i++) { 426 if (gelf_getphdr(elf, i, &phdr) == NULL) { 427 warnx("%s: %s", fname, elf_errmsg(0)); 428 elf_end(elf); 429 return (0); 430 } 431 switch (phdr.p_type) { 432 case PT_NOTE: 433 if (ehdr.e_ident[EI_OSABI] == ELFOSABI_NONE && !freebsd) 434 freebsd = has_freebsd_abi_tag(fname, elf, &ehdr, 435 phdr.p_offset, phdr.p_filesz); 436 break; 437 case PT_DYNAMIC: 438 dynamic = true; 439 if (ehdr.e_type == ET_DYN) 440 pie = is_pie(fname, elf, &ehdr, phdr.p_offset, 441 phdr.p_filesz); 442 break; 443 } 444 } 445 446 if (!dynamic) { 447 elf_end(elf); 448 warnx("%s: not a dynamic ELF executable", fname); 449 return (0); 450 } 451 452 if (ehdr.e_type == ET_DYN && !pie) { 453 *is_shlib = 1; 454 455 if (!freebsd) { 456 elf_end(elf); 457 warnx("%s: not a FreeBSD ELF shared object", fname); 458 return (0); 459 } 460 } 461 462 elf_end(elf); 463 return (1); 464 } 465