utils/ldd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * A small little ldd implementation for uClibc
   4  *
   5  * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
   6  *
   7  * Several functions in this file (specifically, elf_find_section_type(),
   8  * elf_find_phdr_type(), and elf_find_dynamic(), were stolen from elflib.c from
   9  * elfvector (http://www.BitWagon.com/elfvector.html) by John F. Reiser
  10  * <jreiser@BitWagon.com>, which is copyright 2000 BitWagon Software LLC
  11  * (GPL2).
  12  *
  13  * Licensed under GPLv2 or later
  14  */
  15
  16 #include "porting.h"
  17
  18 #if defined(__alpha__)
  19 #define MATCH_MACHINE(x) (x == EM_ALPHA)
  20 #define ELFCLASSM       ELFCLASS64
  21 #endif
  22
  23 #if defined(__arc__)
  24 #define MATCH_MACHINE(x) (x == EM_ARCOMPACT)
  25 #define ELFCLASSM      ELFCLASS32
  26 #endif
  27
  28 #if defined(__arm__) || defined(__thumb__)
  29 #define MATCH_MACHINE(x) (x == EM_ARM)
  30 #define ELFCLASSM       ELFCLASS32
  31 #endif
  32
  33 #if defined(__avr32__)
  34 #define MATCH_MACHINE(x) (x == EM_AVR32)
  35 #define ELFCLASSM      ELFCLASS32
  36 #endif
  37
  38 #if defined(__s390__)
  39 #define MATCH_MACHINE(x) (x == EM_S390)
  40 #define ELFCLASSM       ELFCLASS32
  41 #endif
  42
  43 #if defined(__hppa__)
  44 #define MATCH_MACHINE(x) (x == EM_PARISC)
  45 #if defined(__LP64__)
  46 #define ELFCLASSM               ELFCLASS64
  47 #else
  48 #define ELFCLASSM               ELFCLASS32
  49 #endif
  50 #endif
  51
  52 #if defined(__i386__)
  53 #ifndef EM_486
  54 #define MATCH_MACHINE(x) (x == EM_386)
  55 #else
  56 #define MATCH_MACHINE(x) (x == EM_386 || x == EM_486)
  57 #endif
  58 #define ELFCLASSM       ELFCLASS32
  59 #endif
  60
  61 #if defined(__ia64__)
  62 #define MATCH_MACHINE(x) (x == EM_IA_64)
  63 #define ELFCLASSM       ELFCLASS64
  64 #endif
  65
  66 #if defined(__mc68000__)
  67 #define MATCH_MACHINE(x) (x == EM_68K)
  68 #define ELFCLASSM       ELFCLASS32
  69 #endif
  70
  71 #if defined(__metag__)
  72 #define MATCH_MACHINE(x) (x == EM_METAG)
  73 #define ELFCLASSM       ELFCLASS32
  74 #endif
  75
  76 #if defined(__mips__)
  77 #define MATCH_MACHINE(x) (x == EM_MIPS || x == EM_MIPS_RS3_LE)
  78 #define ELFCLASSM       ELFCLASS32
  79 #endif
  80
  81 #if defined(__powerpc64__)
  82 #define MATCH_MACHINE(x) (x == EM_PPC64)
  83 #define ELFCLASSM       ELFCLASS64
  84 #elif defined(__powerpc__)
  85 #define MATCH_MACHINE(x) (x == EM_PPC)
  86 #define ELFCLASSM       ELFCLASS32
  87 #endif
  88
  89 #if defined(__sh__)
  90 #define MATCH_MACHINE(x) (x == EM_SH)
  91 #define ELFCLASSM       ELFCLASS32
  92 #endif
  93
  94 #if defined(__v850e__)
  95 #define MATCH_MACHINE(x) ((x) == EM_V850 || (x) == EM_CYGNUS_V850)
  96 #define ELFCLASSM       ELFCLASS32
  97 #endif
  98
  99 #if defined(__sparc__)
 100 #define MATCH_MACHINE(x) ((x) == EM_SPARC || (x) == EM_SPARC32PLUS)
 101 #define ELFCLASSM    ELFCLASS32
 102 #endif
 103
 104 #if defined(__cris__)
 105 #define MATCH_MACHINE(x) (x == EM_CRIS)
 106 #define ELFCLASSM       ELFCLASS32
 107 #endif
 108
 109 #if defined(__x86_64__)
 110 #define MATCH_MACHINE(x) (x == EM_X86_64)
 111 #define ELFCLASSM       ELFCLASS64
 112 #endif
 113
 114 #if defined(__microblaze__)
 115 #define MATCH_MACHINE(x) (x == EM_MICROBLAZE_OLD)
 116 #define ELFCLASSM       ELFCLASS32
 117 #endif
 118
 119 #if defined(__xtensa__)
 120 #define MATCH_MACHINE(x) (x == EM_XTENSA)
 121 #define ELFCLASSM       ELFCLASS32
 122 #endif
 123
 124 #ifndef MATCH_MACHINE
 125 # ifdef __linux__
 126 #  include <asm/elf.h>
 127 # endif
 128 # ifdef ELF_ARCH
 129 #  define MATCH_MACHINE(x) (x == ELF_ARCH)
 130 # endif
 131 # ifdef ELF_CLASS
 132 #  define ELFCLASSM ELF_CLASS
 133 # endif
 134 #endif
 135 #ifndef MATCH_MACHINE
 136 # warning "You really should add a MATCH_MACHINE() macro for your architecture"
 137 #endif
 138
 139 #if UCLIBC_ENDIAN_HOST == UCLIBC_ENDIAN_LITTLE
 140 #define ELFDATAM        ELFDATA2LSB
 141 #elif UCLIBC_ENDIAN_HOST == UCLIBC_ENDIAN_BIG
 142 #define ELFDATAM        ELFDATA2MSB
 143 #endif
 144
 145 #define TRUSTED_LDSO    UCLIBC_RUNTIME_PREFIX "lib/" UCLIBC_LDSO
 146
 147 struct library {
 148         char *name;
 149         int resolved;
 150         char *path;
 151         struct library *next;
 152 };
 153 static struct library *lib_list = NULL;
 154 static char not_found[] = "not found";
 155 static char *interp_name = NULL;
 156 static char *interp_dir = NULL;
 157 static int byteswap;
 158 static int interpreter_already_found = 0;
 159
 160 static __inline__ uint32_t byteswap32_to_host(uint32_t value)
 161 {
 162         if (byteswap) {
 163                 return (bswap_32(value));
 164         } else {
 165                 return (value);
 166         }
 167 }
 168 static __inline__ uint64_t byteswap64_to_host(uint64_t value)
 169 {
 170         if (byteswap) {
 171                 return (bswap_64(value));
 172         } else {
 173                 return (value);
 174         }
 175 }
 176
 177 #if ELFCLASSM == ELFCLASS32
 178 # define byteswap_to_host(x) byteswap32_to_host(x)
 179 #else
 180 # define byteswap_to_host(x) byteswap64_to_host(x)
 181 #endif
 182
 183 static ElfW(Shdr) *elf_find_section_type(uint32_t key, ElfW(Ehdr) *ehdr)
 184 {
 185         int j;
 186         ElfW(Shdr) *shdr;
 187         shdr = (ElfW(Shdr) *) (ehdr->e_shoff + (char *)ehdr);
 188         for (j = ehdr->e_shnum; --j >= 0; ++shdr) {
 189                 if (key == byteswap32_to_host(shdr->sh_type)) {
 190                         return shdr;
 191                 }
 192         }
 193         return NULL;
 194 }
 195
 196 static ElfW(Phdr) *elf_find_phdr_type(uint32_t type, ElfW(Ehdr) *ehdr)
 197 {
 198         int j;
 199         ElfW(Phdr) *phdr = (ElfW(Phdr) *) (ehdr->e_phoff + (char *)ehdr);
 200         for (j = ehdr->e_phnum; --j >= 0; ++phdr) {
 201                 if (type == byteswap32_to_host(phdr->p_type)) {
 202                         return phdr;
 203                 }
 204         }
 205         return NULL;
 206 }
 207
 208 /* Returns value if return_val==1, ptr otherwise */
 209 static void *elf_find_dynamic(int64_t const key, ElfW(Dyn) *dynp,
 210                        ElfW(Ehdr) *ehdr, int return_val)
 211 {
 212         ElfW(Phdr) *pt_text = elf_find_phdr_type(PT_LOAD, ehdr);
 213         unsigned tx_reloc = byteswap_to_host(pt_text->p_vaddr) - byteswap_to_host(pt_text->p_offset);
 214         for (; DT_NULL != byteswap_to_host(dynp->d_tag); ++dynp) {
 215                 if (key == byteswap_to_host(dynp->d_tag)) {
 216                         if (return_val == 1)
 217                                 return (void *)byteswap_to_host(dynp->d_un.d_val);
 218                         else
 219                                 return (void *)(byteswap_to_host(dynp->d_un.d_val) - tx_reloc + (char *)ehdr);
 220                 }
 221         }
 222         return NULL;
 223 }
 224
 225 static char *elf_find_rpath(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic)
 226 {
 227         ElfW(Dyn) *dyns;
 228
 229         for (dyns = dynamic; byteswap_to_host(dyns->d_tag) != DT_NULL; ++dyns) {
 230                 if (DT_RPATH == byteswap_to_host(dyns->d_tag)) {
 231                         char *strtab;
 232                         strtab = (char *)elf_find_dynamic(DT_STRTAB, dynamic, ehdr, 0);
 233                         return ((char *)strtab + byteswap_to_host(dyns->d_un.d_val));
 234                 }
 235         }
 236         return NULL;
 237 }
 238
 239 static int check_elf_header(ElfW(Ehdr) *const ehdr)
 240 {
 241         if (!ehdr || *(uint32_t*)ehdr != ELFMAG_U32
 242          || ehdr->e_ident[EI_CLASS] != ELFCLASSM
 243          || ehdr->e_ident[EI_VERSION] != EV_CURRENT
 244         ) {
 245                 return 1;
 246         }
 247
 248         /* Check if the target endianness matches the host's endianness */
 249         byteswap = !(ehdr->e_ident[5] == ELFDATAM);
 250
 251         /* Be very lazy, and only byteswap the stuff we use */
 252         if (byteswap) {
 253                 ehdr->e_type = bswap_16(ehdr->e_type);
 254                 ehdr->e_phoff = byteswap_to_host(ehdr->e_phoff);
 255                 ehdr->e_shoff = byteswap_to_host(ehdr->e_shoff);
 256                 ehdr->e_phnum = bswap_16(ehdr->e_phnum);
 257                 ehdr->e_shnum = bswap_16(ehdr->e_shnum);
 258         }
 259
 260         return 0;
 261 }
 262
 263 #ifdef __LDSO_CACHE_SUPPORT__
 264 static caddr_t cache_addr = NULL;
 265 static size_t cache_size = 0;
 266
 267 static int map_cache(void)
 268 {
 269         int fd;
 270         struct stat st;
 271         header_t *header;
 272         libentry_t *libent;
 273         int i, strtabsize;
 274
 275         if (cache_addr == (caddr_t) - 1)
 276                 return -1;
 277         else if (cache_addr != NULL)
 278                 return 0;
 279
 280         if (stat(LDSO_CACHE, &st) || (fd = open(LDSO_CACHE, O_RDONLY)) < 0) {
 281                 fprintf(stderr, "ldd: can't open cache '%s'\n", LDSO_CACHE);
 282                 cache_addr = (caddr_t) - 1;     /* so we won't try again */
 283                 return -1;
 284         }
 285
 286         cache_size = st.st_size;
 287         cache_addr = mmap(0, cache_size, PROT_READ, MAP_SHARED, fd, 0);
 288         close(fd);
 289         if (cache_addr == MAP_FAILED) {
 290                 fprintf(stderr, "ldd: can't map cache '%s'\n", LDSO_CACHE);
 291                 return -1;
 292         }
 293
 294         header = (header_t *) cache_addr;
 295
 296         if (cache_size < sizeof(header_t)
 297             || memcmp(header->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN)
 298             || memcmp(header->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN)
 299             || cache_size < (sizeof(header_t) + header->nlibs * sizeof(libentry_t))
 300             || cache_addr[cache_size - 1] != '\0')
 301         {
 302                 fprintf(stderr, "ldd: cache '%s' is corrupt\n", LDSO_CACHE);
 303                 goto fail;
 304         }
 305
 306         strtabsize = cache_size - sizeof(header_t) - header->nlibs * sizeof(libentry_t);
 307         libent = (libentry_t *) & header[1];
 308
 309         for (i = 0; i < header->nlibs; i++) {
 310                 if (libent[i].sooffset >= strtabsize || libent[i].liboffset >= strtabsize) {
 311                         fprintf(stderr, "ldd: cache '%s' is corrupt\n", LDSO_CACHE);
 312                         goto fail;
 313                 }
 314         }
 315
 316         return 0;
 317
 318 fail:
 319         munmap(cache_addr, cache_size);
 320         cache_addr = (caddr_t) - 1;
 321         return -1;
 322 }
 323
 324 static int unmap_cache(void)
 325 {
 326         if (cache_addr == NULL || cache_addr == (caddr_t) - 1)
 327                 return -1;
 328
 329 #if 1
 330         munmap(cache_addr, cache_size);
 331         cache_addr = NULL;
 332 #endif
 333
 334         return 0;
 335 }
 336 #else
 337 static __inline__ void map_cache(void)
 338 {
 339 }
 340 static __inline__ void unmap_cache(void)
 341 {
 342 }
 343 #endif
 344
 345 /* This function's behavior must exactly match that
 346  * in uClibc/ldso/ldso/dl-elf.c */
 347 static void search_for_named_library(char *name, char *result,
 348                                      const char *path_list)
 349 {
 350         int i, count = 1;
 351         char *path, *path_n;
 352         struct stat filestat;
 353
 354         /* We need a writable copy of this string */
 355         path = strdup(path_list);
 356         if (!path) {
 357                 fprintf(stderr, "%s: Out of memory!\n", __func__);
 358                 exit(EXIT_FAILURE);
 359         }
 360         /* Eliminate all double //s */
 361         path_n = path;
 362         while ((path_n = strstr(path_n, "//"))) {
 363                 i = strlen(path_n);
 364                 memmove(path_n, path_n + 1, i - 1);
 365                 *(path_n + i - 1) = '\0';
 366         }
 367
 368         /* Replace colons with zeros in path_list and count them */
 369         for (i = strlen(path); i > 0; i--) {
 370                 if (path[i] == ':') {
 371                         path[i] = 0;
 372                         count++;
 373                 }
 374         }
 375         path_n = path;
 376         for (i = 0; i < count; i++) {
 377                 strcpy(result, path_n);
 378                 strcat(result, "/");
 379                 strcat(result, name);
 380                 if (stat(result, &filestat) == 0 && filestat.st_mode & S_IRUSR) {
 381                         free(path);
 382                         return;
 383                 }
 384                 path_n += (strlen(path_n) + 1);
 385         }
 386         free(path);
 387         *result = '\0';
 388 }
 389
 390 static void locate_library_file(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic,
 391                                 int is_suid, struct library *lib)
 392 {
 393         char *buf;
 394         char *path;
 395         struct stat filestat;
 396
 397         /* If this is a fully resolved name, our job is easy */
 398         if (stat(lib->name, &filestat) == 0) {
 399                 lib->path = strdup(lib->name);
 400                 return;
 401         }
 402
 403         /* We need some elbow room here.  Make some room... */
 404         buf = malloc(1024);
 405         if (!buf) {
 406                 fprintf(stderr, "%s: Out of memory!\n", __func__);
 407                 exit(EXIT_FAILURE);
 408         }
 409
 410         /* This function must match the behavior of _dl_load_shared_library
 411          * in readelflib1.c or things won't work out as expected... */
 412
 413         /* The ABI specifies that RPATH is searched first, so do that now.  */
 414         path = elf_find_rpath(ehdr, dynamic);
 415         if (path) {
 416                 search_for_named_library(lib->name, buf, path);
 417                 if (*buf != '\0') {
 418                         lib->path = buf;
 419                         return;
 420                 }
 421         }
 422
 423         /* Next check LD_{ELF_}LIBRARY_PATH if specified and allowed.
 424          * Since this app doesn't actually run an executable I will skip
 425          * the suid check, and just use LD_{ELF_}LIBRARY_PATH if set */
 426         if (is_suid == 1)
 427                 path = NULL;
 428         else
 429                 path = getenv("LD_LIBRARY_PATH");
 430         if (path) {
 431                 search_for_named_library(lib->name, buf, path);
 432                 if (*buf != '\0') {
 433                         lib->path = buf;
 434                         return;
 435                 }
 436         }
 437 #ifdef __LDSO_CACHE_SUPPORT__
 438         if (cache_addr != NULL && cache_addr != (caddr_t) - 1) {
 439                 int i;
 440                 header_t *header = (header_t *) cache_addr;
 441                 libentry_t *libent = (libentry_t *) & header[1];
 442                 char *strs = (char *)&libent[header->nlibs];
 443
 444                 for (i = 0; i < header->nlibs; i++) {
 445                         if ((libent[i].flags == LIB_ELF ||
 446                              libent[i].flags == LIB_ELF_LIBC0 ||
 447                              libent[i].flags == LIB_ELF_LIBC5) &&
 448                             strcmp(lib->name, strs + libent[i].sooffset) == 0)
 449                         {
 450                                 lib->path = strdup(strs + libent[i].liboffset);
 451                                 return;
 452                         }
 453                 }
 454         }
 455 #endif
 456
 457         /* Next look for libraries wherever the shared library
 458          * loader was installed -- this is usually where we
 459          * should find things... */
 460         if (interp_dir) {
 461                 search_for_named_library(lib->name, buf, interp_dir);
 462                 if (*buf != '\0') {
 463                         lib->path = buf;
 464                         return;
 465                 }
 466         }
 467
 468         /* Lastly, search the standard list of paths for the library.
 469            This list must exactly match the list in uClibc/ldso/ldso/dl-elf.c */
 470         path = UCLIBC_RUNTIME_PREFIX "lib:" UCLIBC_RUNTIME_PREFIX "usr/lib"
 471 #ifndef __LDSO_CACHE_SUPPORT__
 472             ":" UCLIBC_RUNTIME_PREFIX "usr/X11R6/lib"
 473 #endif
 474             ;
 475         search_for_named_library(lib->name, buf, path);
 476         if (*buf != '\0') {
 477                 lib->path = buf;
 478         } else {
 479                 free(buf);
 480                 lib->path = not_found;
 481         }
 482 }
 483
 484 static int add_library(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic, int is_setuid, char *s)
 485 {
 486         char *tmp, *tmp1, *tmp2;
 487         struct library *cur, *newlib = lib_list;
 488
 489         if (!s || !strlen(s))
 490                 return 1;
 491
 492         tmp = s;
 493         while (*tmp) {
 494                 if (*tmp == '/')
 495                         s = tmp + 1;
 496                 tmp++;
 497         }
 498
 499         /* We add ldso elsewhere */
 500         if (interpreter_already_found && (tmp = strrchr(interp_name, '/')) != NULL) {
 501                 int len = strlen(interp_dir);
 502                 if (strcmp(s, interp_name + 1 + len) == 0)
 503                         return 1;
 504         }
 505
 506         for (cur = lib_list; cur; cur = cur->next) {
 507                 /* Check if this library is already in the list */
 508                 tmp1 = tmp2 = cur->name;
 509                 while (*tmp1) {
 510                         if (*tmp1 == '/')
 511                                 tmp2 = tmp1 + 1;
 512                         tmp1++;
 513                 }
 514                 if (strcmp(tmp2, s) == 0) {
 515                         /*printf("find_elf_interpreter is skipping '%s' (already in list)\n", cur->name); */
 516                         return 0;
 517                 }
 518         }
 519
 520         /* Ok, this lib needs to be added to the list */
 521         newlib = malloc(sizeof(struct library));
 522         if (!newlib)
 523                 return 1;
 524         newlib->name = malloc(strlen(s) + 1);
 525         strcpy(newlib->name, s);
 526         newlib->resolved = 0;
 527         newlib->path = NULL;
 528         newlib->next = NULL;
 529
 530         /* Now try and locate where this library might be living... */
 531         locate_library_file(ehdr, dynamic, is_setuid, newlib);
 532
 533         /*printf("add_library is adding '%s' to '%s'\n", newlib->name, newlib->path); */
 534         if (!lib_list) {
 535                 lib_list = newlib;
 536         } else {
 537                 for (cur = lib_list; cur->next; cur = cur->next) ;      /* nothing */
 538                 cur->next = newlib;
 539         }
 540         return 0;
 541 }
 542
 543 static void find_needed_libraries(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic, int is_setuid)
 544 {
 545         ElfW(Dyn) *dyns;
 546
 547         for (dyns = dynamic; byteswap_to_host(dyns->d_tag) != DT_NULL; ++dyns) {
 548                 if (DT_NEEDED == byteswap_to_host(dyns->d_tag)) {
 549                         char *strtab;
 550                         strtab = (char *)elf_find_dynamic(DT_STRTAB, dynamic, ehdr, 0);
 551                         add_library(ehdr, dynamic, is_setuid, (char *)strtab + byteswap_to_host(dyns->d_un.d_val));
 552                 }
 553         }
 554 }
 555
 556 #ifdef __LDSO_LDD_SUPPORT__
 557 static struct library *find_elf_interpreter(ElfW(Ehdr) *ehdr)
 558 {
 559         ElfW(Phdr) *phdr;
 560
 561         if (interpreter_already_found == 1)
 562                 return NULL;
 563         phdr = elf_find_phdr_type(PT_INTERP, ehdr);
 564         if (phdr) {
 565                 struct library *cur, *newlib = NULL;
 566                 char *s = (char *)ehdr + byteswap_to_host(phdr->p_offset);
 567
 568                 char *tmp, *tmp1;
 569                 interp_name = strdup(s);
 570                 interp_dir = strdup(s);
 571                 tmp = strrchr(interp_dir, '/');
 572                 if (tmp)
 573                         *tmp = '\0';
 574                 else {
 575                         free(interp_dir);
 576                         interp_dir = interp_name;
 577                 }
 578                 tmp1 = tmp = s;
 579                 while (*tmp) {
 580                         if (*tmp == '/')
 581                                 tmp1 = tmp + 1;
 582                         tmp++;
 583                 }
 584                 for (cur = lib_list; cur; cur = cur->next) {
 585                         /* Check if this library is already in the list */
 586                         if (strcmp(cur->name, tmp1) == 0) {
 587                                 /*printf("find_elf_interpreter is replacing '%s' (already in list)\n", cur->name); */
 588                                 newlib = cur;
 589                                 free(newlib->name);
 590                                 if (newlib->path != not_found) {
 591                                         free(newlib->path);
 592                                 }
 593                                 newlib->name = NULL;
 594                                 newlib->path = NULL;
 595                                 break;
 596                         }
 597                 }
 598                 if (newlib == NULL)
 599                         newlib = malloc(sizeof(struct library));
 600                 if (!newlib)
 601                         return NULL;
 602                 newlib->name = malloc(strlen(s) + 1);
 603                 strcpy(newlib->name, s);
 604                 newlib->path = strdup(newlib->name);
 605                 newlib->resolved = 1;
 606                 newlib->next = NULL;
 607
 608 #if 0
 609                 /*printf("find_elf_interpreter is adding '%s' to '%s'\n", newlib->name, newlib->path); */
 610                 if (!lib_list) {
 611                         lib_list = newlib;
 612                 } else {
 613                         for (cur = lib_list; cur->next; cur = cur->next) ;      /* nothing */
 614                         cur->next = newlib;
 615                 }
 616 #endif
 617                 interpreter_already_found = 1;
 618                 return newlib;
 619         }
 620         return NULL;
 621 }
 622 #endif /* __LDSO_LDD_SUPPORT__ */
 623
 624 /* map the .so, and locate interesting pieces */
 625 /*
 626 #warning "There may be two warnings here about vfork() clobbering, ignore them"
 627 */
 628 static int find_dependencies(char *filename)
 629 {
 630         int is_suid = 0;
 631         FILE *thefile;
 632         struct stat statbuf;
 633         ElfW(Ehdr) *ehdr = NULL;
 634         ElfW(Shdr) *dynsec = NULL;
 635         ElfW(Dyn) *dynamic = NULL;
 636 #ifdef __LDSO_LDD_SUPPORT__
 637         struct library *interp;
 638 #endif
 639
 640         if (filename == not_found)
 641                 return 0;
 642
 643         if (!filename) {
 644                 fprintf(stderr, "No filename specified.\n");
 645                 return -1;
 646         }
 647         if (!(thefile = fopen(filename, "r"))) {
 648                 perror(filename);
 649                 return -1;
 650         }
 651         if (fstat(fileno(thefile), &statbuf) < 0) {
 652                 perror(filename);
 653                 fclose(thefile);
 654                 return -1;
 655         }
 656
 657         if ((size_t) statbuf.st_size < sizeof(ElfW(Ehdr)))
 658                 goto foo;
 659
 660         if (!S_ISREG(statbuf.st_mode))
 661                 goto foo;
 662
 663         /* mmap the file to make reading stuff from it effortless */
 664         ehdr = mmap(0, statbuf.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fileno(thefile), 0);
 665         if (ehdr == MAP_FAILED) {
 666                 fclose(thefile);
 667                 fprintf(stderr, "mmap(%s) failed: %s\n", filename, strerror(errno));
 668                 return -1;
 669         }
 670
 671 foo:
 672         fclose(thefile);
 673
 674         /* Check if this looks like a legit ELF file */
 675         if (check_elf_header(ehdr)) {
 676                 fprintf(stderr, "%s: not an ELF file.\n", filename);
 677                 return -1;
 678         }
 679         /* Check if this is the right kind of ELF file */
 680         if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
 681                 fprintf(stderr, "%s: not a dynamic executable\n", filename);
 682                 return -1;
 683         }
 684         if (ehdr->e_type == ET_EXEC || ehdr->e_type == ET_DYN) {
 685                 if (statbuf.st_mode & S_ISUID)
 686                         is_suid = 1;
 687                 if ((statbuf.st_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
 688                         is_suid = 1;
 689                 /* FIXME */
 690                 if (is_suid)
 691                         fprintf(stderr, "%s: is setuid\n", filename);
 692         }
 693
 694         interpreter_already_found = 0;
 695 #ifdef __LDSO_LDD_SUPPORT__
 696         interp = find_elf_interpreter(ehdr);
 697
 698         if (interp
 699             && (ehdr->e_type == ET_EXEC || ehdr->e_type == ET_DYN)
 700             && ehdr->e_ident[EI_CLASS] == ELFCLASSM
 701             && ehdr->e_ident[EI_DATA] == ELFDATAM
 702             && ehdr->e_ident[EI_VERSION] == EV_CURRENT
 703             && MATCH_MACHINE(ehdr->e_machine))
 704         {
 705                 struct stat st;
 706                 if (stat(interp->path, &st) == 0 && S_ISREG(st.st_mode)) {
 707                         pid_t pid;
 708                         int status;
 709                         static const char *const environment[] = {
 710                                 "PATH=/usr/bin:/bin:/usr/sbin:/sbin",
 711                                 "SHELL=/bin/sh",
 712                                 "LD_TRACE_LOADED_OBJECTS=1",
 713                                 NULL
 714                         };
 715 # ifdef __LDSO_STANDALONE_SUPPORT__
 716                         char * lib_path = getenv("LD_LIBRARY_PATH");
 717
 718                         /* The 'extended' environment inclusing the LD_LIBRARY_PATH */
 719                         static char *ext_environment[ARRAY_SIZE(environment) + 1];
 720                         char **envp = (char **) environment;
 721
 722                         if (lib_path) {
 723                                 /*
 724                                  * If the LD_LIBRARY_PATH is set, it needs to include it
 725                                  * into the environment for the new process to be spawned
 726                                  */
 727                                 char ** eenvp = (char **) ext_environment;
 728
 729                                 /* Copy the N-1 environment's entries */
 730                                 while (*envp)
 731                                         *eenvp++=*envp++;
 732
 733                                 /* Make room for LD_LIBRARY_PATH */
 734                                 *eenvp = (char *) malloc(sizeof("LD_LIBRARY_PATH=")
 735                                                                           + strlen(lib_path));
 736                                 strcpy(*eenvp, "LD_LIBRARY_PATH=");
 737                                 strcat(*eenvp, lib_path);
 738                                 lib_path = *eenvp;
 739                                 /* ext_environment[size] is already NULL */
 740
 741                                 /* Use the extended environment */
 742                                 envp = ext_environment;
 743                         }
 744                         if ((pid = vfork()) == 0) {
 745                                 /*
 746                                  * Force to use the standard dynamic linker in stand-alone mode.
 747                                  * It will fails at runtime if support is not actually available
 748                                  */
 749                                 execle(TRUSTED_LDSO, TRUSTED_LDSO, filename, NULL, envp);
 750                                 _exit(0xdead);
 751                         }
 752 # else
 753                         if ((pid = vfork()) == 0) {
 754                                 /* Cool, it looks like we should be able to actually
 755                                  * run this puppy.  Do so now... */
 756                                 execle(filename, filename, NULL, environment);
 757                                 _exit(0xdead);
 758                         }
 759 # endif
 760                         /* Wait till it returns */
 761                         waitpid(pid, &status, 0);
 762
 763 # ifdef __LDSO_STANDALONE_SUPPORT__
 764                         /* Do not leak */
 765                         free(lib_path);
 766 # endif
 767
 768                         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 769                                 return 1;
 770                         }
 771
 772                         /* If the exec failed, we fall through to trying to find
 773                          * all the needed libraries ourselves by rummaging about
 774                          * in the ELF headers... */
 775                 }
 776         }
 777 #endif
 778
 779         dynsec = elf_find_section_type(SHT_DYNAMIC, ehdr);
 780         if (dynsec) {
 781                 dynamic = (ElfW(Dyn) *) (byteswap_to_host(dynsec->sh_offset) + (char *)ehdr);
 782                 find_needed_libraries(ehdr, dynamic, is_suid);
 783         }
 784
 785         return 0;
 786 }
 787
 788 int main(int argc, char **argv)
 789 {
 790         int multi = 0;
 791         int got_em_all = 1;
 792         char *filename = NULL;
 793         struct library *cur;
 794
 795         if (argc < 2) {
 796                 fprintf(stderr, "ldd: missing file arguments\n"
 797                                 "Try `ldd --help' for more information.\n");
 798                 exit(EXIT_FAILURE);
 799         }
 800         if (argc > 2)
 801                 multi++;
 802
 803         while (--argc > 0) {
 804                 ++argv;
 805
 806                 if (strcmp(*argv, "--") == 0) {
 807                         /* Ignore "--" */
 808                         continue;
 809                 }
 810
 811                 if (strcmp(*argv, "--help") == 0 || strcmp(*argv, "-h") == 0) {
 812                         fprintf(stderr, "Usage: ldd [OPTION]... FILE...\n"
 813                                         "\t--help\t\tprint this help and exit\n");
 814                         exit(EXIT_SUCCESS);
 815                 }
 816
 817                 filename = *argv;
 818                 if (!filename) {
 819                         fprintf(stderr, "No filename specified.\n");
 820                         exit(EXIT_FAILURE);
 821                 }
 822
 823                 if (multi) {
 824                         printf("%s:\n", *argv);
 825                 }
 826
 827                 map_cache();
 828
 829                 if (find_dependencies(filename) != 0)
 830                         continue;
 831
 832                 while (got_em_all) {
 833                         got_em_all = 0;
 834                         /* Keep walking the list till everybody is resolved */
 835                         for (cur = lib_list; cur; cur = cur->next) {
 836                                 if (cur->resolved == 0 && cur->path) {
 837                                         got_em_all = 1;
 838                                         printf("checking sub-depends for '%s'\n", cur->path);
 839                                         find_dependencies(cur->path);
 840                                         cur->resolved = 1;
 841                                 }
 842                         }
 843                 }
 844
 845                 unmap_cache();
 846
 847                 /* Print the list */
 848                 got_em_all = 0;
 849                 for (cur = lib_list; cur; cur = cur->next) {
 850                         got_em_all = 1;
 851                         printf("\t%s => %s (0x00000000)\n", cur->name, cur->path);
 852                 }
 853                 if (interp_name && interpreter_already_found == 1)
 854                         printf("\t%s => %s (0x00000000)\n", interp_name, interp_name);
 855                 else
 856                         printf("\tnot a dynamic executable\n");
 857
 858                 for (cur = lib_list; cur; cur = cur->next) {
 859                         free(cur->name);
 860                         cur->name = NULL;
 861                         if (cur->path && cur->path != not_found) {
 862                                 free(cur->path);
 863                                 cur->path = NULL;
 864                         }
 865                 }
 866                 lib_list = NULL;
 867         }
 868
 869         return 0;
 870 }