usr.bin/ldd/ldd.c

   1 /*
   2  * Copyright (c) 1993 Paul Kranenburg
   3  * 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 Paul Kranenburg.
  16  * 4. The name of the author may not be used to endorse or promote products
  17  *    derived from this software without specific prior written permission
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD$");
  33
  34 #include <sys/wait.h>
  35
  36 #include <machine/elf.h>
  37
  38 #include <arpa/inet.h>
  39
  40 #include <dlfcn.h>
  41 #include <err.h>
  42 #include <errno.h>
  43 #include <fcntl.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48
  49 #include "extern.h"
  50
  51 /* We don't support a.out executables on arm64 and riscv */
  52 #if !defined(__aarch64__) && !defined(__riscv__)
  53 #include <a.out.h>
  54 #define AOUT_SUPPORTED
  55 #endif
  56
  57 /*
  58  * 32-bit ELF data structures can only be used if the system header[s] declare
  59  * them.  There is no official macro for determining whether they are declared,
  60  * so check for the existence of one of the 32-macros defined in elf(5).
  61  */
  62 #ifdef ELF32_R_TYPE
  63 #define ELF32_SUPPORTED
  64 #endif
  65
  66 #define LDD_SETENV(name, value, overwrite) do {         \
  67         setenv("LD_" name, value, overwrite);           \
  68         setenv("LD_32_" name, value, overwrite);        \
  69 } while (0)
  70
  71 #define LDD_UNSETENV(name) do {         \
  72         unsetenv("LD_" name);           \
  73         unsetenv("LD_32_" name);        \
  74 } while (0)
  75
  76 static int      is_executable(const char *fname, int fd, int *is_shlib,
  77                     int *type);
  78 static void     usage(void);
  79
  80 #define TYPE_UNKNOWN    0
  81 #define TYPE_AOUT       1
  82 #define TYPE_ELF        2       /* Architecture default */
  83 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
  84 #define TYPE_ELF32      3       /* Explicit 32 bits on architectures >32 bits */
  85
  86 #define _PATH_LDD32     "/usr/bin/ldd32"
  87
  88 static int
  89 execldd32(char *file, char *fmt1, char *fmt2, int aflag, int vflag)
  90 {
  91         char *argv[8];
  92         int i, rval, status;
  93
  94         LDD_UNSETENV("TRACE_LOADED_OBJECTS");
  95         rval = 0;
  96         i = 0;
  97         argv[i++] = strdup(_PATH_LDD32);
  98         if (aflag)
  99                 argv[i++] = strdup("-a");
 100         if (vflag)
 101                 argv[i++] = strdup("-v");
 102         if (fmt1 != NULL) {
 103                 argv[i++] = strdup("-f");
 104                 argv[i++] = strdup(fmt1);
 105         }
 106         if (fmt2 != NULL) {
 107                 argv[i++] = strdup("-f");
 108                 argv[i++] = strdup(fmt2);
 109         }
 110         argv[i++] = strdup(file);
 111         argv[i++] = NULL;
 112
 113         switch (fork()) {
 114         case -1:
 115                 err(1, "fork");
 116                 break;
 117         case 0:
 118                 execv(_PATH_LDD32, argv);
 119                 warn("%s", _PATH_LDD32);
 120                 _exit(127);
 121                 break;
 122         default:
 123                 if (wait(&status) < 0)
 124                         rval = 1;
 125                 else if (WIFSIGNALED(status))
 126                         rval = 1;
 127                 else if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
 128                         rval = 1;
 129                 break;
 130         }
 131         while (i--)
 132                 free(argv[i]);
 133         LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1);
 134         return (rval);
 135 }
 136 #endif
 137
 138 int
 139 main(int argc, char *argv[])
 140 {
 141         char *fmt1, *fmt2;
 142         int rval, c, aflag, vflag;
 143
 144         aflag = vflag = 0;
 145         fmt1 = fmt2 = NULL;
 146
 147         while ((c = getopt(argc, argv, "af:v")) != -1) {
 148                 switch (c) {
 149                 case 'a':
 150                         aflag++;
 151                         break;
 152                 case 'f':
 153                         if (fmt1 != NULL) {
 154                                 if (fmt2 != NULL)
 155                                         errx(1, "too many formats");
 156                                 fmt2 = optarg;
 157                         } else
 158                                 fmt1 = optarg;
 159                         break;
 160                 case 'v':
 161                         vflag++;
 162                         break;
 163                 default:
 164                         usage();
 165                         /* NOTREACHED */
 166                 }
 167         }
 168         argc -= optind;
 169         argv += optind;
 170
 171         if (vflag && fmt1 != NULL)
 172                 errx(1, "-v may not be used with -f");
 173
 174         if (argc <= 0) {
 175                 usage();
 176                 /* NOTREACHED */
 177         }
 178
 179 #ifdef __i386__
 180         if (vflag) {
 181                 for (c = 0; c < argc; c++)
 182                         dump_file(argv[c]);
 183                 exit(error_count == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 184         }
 185 #endif
 186
 187         rval = 0;
 188         for (; argc > 0; argc--, argv++) {
 189                 int fd, status, is_shlib, rv, type;
 190
 191                 if ((fd = open(*argv, O_RDONLY, 0)) < 0) {
 192                         warn("%s", *argv);
 193                         rval |= 1;
 194                         continue;
 195                 }
 196                 rv = is_executable(*argv, fd, &is_shlib, &type);
 197                 close(fd);
 198                 if (rv == 0) {
 199                         rval |= 1;
 200                         continue;
 201                 }
 202
 203                 switch (type) {
 204                 case TYPE_ELF:
 205                 case TYPE_AOUT:
 206                         break;
 207 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
 208                 case TYPE_ELF32:
 209                         rval |= execldd32(*argv, fmt1, fmt2, aflag, vflag);
 210                         continue;
 211 #endif
 212                 case TYPE_UNKNOWN:
 213                 default:
 214                         /*
 215                          * This shouldn't happen unless is_executable()
 216                          * is broken.
 217                          */
 218                         errx(EDOOFUS, "unknown executable type");
 219                 }
 220
 221                 /* ld.so magic */
 222                 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1);
 223                 if (fmt1 != NULL)
 224                         LDD_SETENV("TRACE_LOADED_OBJECTS_FMT1", fmt1, 1);
 225                 if (fmt2 != NULL)
 226                         LDD_SETENV("TRACE_LOADED_OBJECTS_FMT2", fmt2, 1);
 227
 228                 LDD_SETENV("TRACE_LOADED_OBJECTS_PROGNAME", *argv, 1);
 229                 if (aflag)
 230                         LDD_SETENV("TRACE_LOADED_OBJECTS_ALL", "1", 1);
 231                 else if (fmt1 == NULL && fmt2 == NULL)
 232                         /* Default formats */
 233                         printf("%s:\n", *argv);
 234                 fflush(stdout);
 235
 236                 switch (fork()) {
 237                 case -1:
 238                         err(1, "fork");
 239                         break;
 240                 default:
 241                         if (wait(&status) < 0) {
 242                                 warn("wait");
 243                                 rval |= 1;
 244                         } else if (WIFSIGNALED(status)) {
 245                                 fprintf(stderr, "%s: signal %d\n", *argv,
 246                                     WTERMSIG(status));
 247                                 rval |= 1;
 248                         } else if (WIFEXITED(status) &&
 249                             WEXITSTATUS(status) != 0) {
 250                                 fprintf(stderr, "%s: exit status %d\n", *argv,
 251                                     WEXITSTATUS(status));
 252                                 rval |= 1;
 253                         }
 254                         break;
 255                 case 0:
 256                         if (is_shlib == 0) {
 257                                 execl(*argv, *argv, (char *)NULL);
 258                                 warn("%s", *argv);
 259                         } else {
 260                                 dlopen(*argv, RTLD_TRACE);
 261                                 warnx("%s: %s", *argv, dlerror());
 262                         }
 263                         _exit(1);
 264                 }
 265         }
 266
 267         return rval;
 268 }
 269
 270 static void
 271 usage(void)
 272 {
 273
 274         fprintf(stderr, "usage: ldd [-a] [-v] [-f format] program ...\n");
 275         exit(1);
 276 }
 277
 278 static int
 279 is_executable(const char *fname, int fd, int *is_shlib, int *type)
 280 {
 281         union {
 282 #ifdef AOUT_SUPPORTED
 283                 struct exec aout;
 284 #endif
 285 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
 286                 Elf32_Ehdr elf32;
 287 #endif
 288                 Elf_Ehdr elf;
 289         } hdr;
 290         int n;
 291
 292         *is_shlib = 0;
 293         *type = TYPE_UNKNOWN;
 294
 295         if ((n = read(fd, &hdr, sizeof(hdr))) == -1) {
 296                 warn("%s: can't read program header", fname);
 297                 return (0);
 298         }
 299
 300 #ifdef AOUT_SUPPORTED
 301         if ((size_t)n >= sizeof(hdr.aout) && !N_BADMAG(hdr.aout)) {
 302                 /* a.out file */
 303                 if ((N_GETFLAG(hdr.aout) & EX_DPMASK) != EX_DYNAMIC
 304 #if 1 /* Compatibility */
 305                     || hdr.aout.a_entry < __LDPGSZ
 306 #endif
 307                         ) {
 308                         warnx("%s: not a dynamic executable", fname);
 309                         return (0);
 310                 }
 311                 *type = TYPE_AOUT;
 312                 return (1);
 313         }
 314 #endif
 315
 316 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
 317         if ((size_t)n >= sizeof(hdr.elf32) && IS_ELF(hdr.elf32) &&
 318             hdr.elf32.e_ident[EI_CLASS] == ELFCLASS32) {
 319                 /* Handle 32 bit ELF objects */
 320                 Elf32_Phdr phdr;
 321                 int dynamic, i;
 322
 323                 dynamic = 0;
 324                 *type = TYPE_ELF32;
 325
 326                 if (lseek(fd, hdr.elf32.e_phoff, SEEK_SET) == -1) {
 327                         warnx("%s: header too short", fname);
 328                         return (0);
 329                 }
 330                 for (i = 0; i < hdr.elf32.e_phnum; i++) {
 331                         if (read(fd, &phdr, hdr.elf32.e_phentsize) !=
 332                             sizeof(phdr)) {
 333                                 warnx("%s: can't read program header", fname);
 334                                 return (0);
 335                         }
 336                         if (phdr.p_type == PT_DYNAMIC) {
 337                                 dynamic = 1;
 338                                 break;
 339                         }
 340                 }
 341
 342                 if (!dynamic) {
 343                         warnx("%s: not a dynamic ELF executable", fname);
 344                         return (0);
 345                 }
 346                 if (hdr.elf32.e_type == ET_DYN) {
 347                         if (hdr.elf32.e_ident[EI_OSABI] == ELFOSABI_FREEBSD) {
 348                                 *is_shlib = 1;
 349                                 return (1);
 350                         }
 351                         warnx("%s: not a FreeBSD ELF shared object", fname);
 352                         return (0);
 353                 }
 354
 355                 return (1);
 356         }
 357 #endif
 358
 359         if ((size_t)n >= sizeof(hdr.elf) && IS_ELF(hdr.elf) &&
 360             hdr.elf.e_ident[EI_CLASS] == ELF_TARG_CLASS) {
 361                 /* Handle default ELF objects on this architecture */
 362                 Elf_Phdr phdr;
 363                 int dynamic, i;
 364
 365                 dynamic = 0;
 366                 *type = TYPE_ELF;
 367
 368                 if (lseek(fd, hdr.elf.e_phoff, SEEK_SET) == -1) {
 369                         warnx("%s: header too short", fname);
 370                         return (0);
 371                 }
 372                 for (i = 0; i < hdr.elf.e_phnum; i++) {
 373                         if (read(fd, &phdr, hdr.elf.e_phentsize)
 374                            != sizeof(phdr)) {
 375                                 warnx("%s: can't read program header", fname);
 376                                 return (0);
 377                         }
 378                         if (phdr.p_type == PT_DYNAMIC) {
 379                                 dynamic = 1;
 380                                 break;
 381                         }
 382                 }
 383
 384                 if (!dynamic) {
 385                         warnx("%s: not a dynamic ELF executable", fname);
 386                         return (0);
 387                 }
 388                 if (hdr.elf.e_type == ET_DYN) {
 389                         switch (hdr.elf.e_ident[EI_OSABI]) {
 390                         case ELFOSABI_FREEBSD:
 391                                 *is_shlib = 1;
 392                                 return (1);
 393 #ifdef __ARM_EABI__
 394                         case ELFOSABI_NONE:
 395                                 if (hdr.elf.e_machine != EM_ARM)
 396                                         break;
 397                                 if (EF_ARM_EABI_VERSION(hdr.elf.e_flags) <
 398                                     EF_ARM_EABI_FREEBSD_MIN)
 399                                         break;
 400                                 *is_shlib = 1;
 401                                 return (1);
 402 #endif
 403                         }
 404                         warnx("%s: not a FreeBSD ELF shared object", fname);
 405                         return (0);
 406                 }
 407
 408                 return (1);
 409         }
 410
 411         warnx("%s: not a dynamic executable", fname);
 412         return (0);
 413 }