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(__sparc__)
  95 #define MATCH_MACHINE(x) ((x) == EM_SPARC || (x) == EM_SPARC32PLUS)
  96 #define ELFCLASSM    ELFCLASS32
  97 #endif
  98
  99 #if defined(__cris__)
 100 #define MATCH_MACHINE(x) (x == EM_CRIS)
 101 #define ELFCLASSM       ELFCLASS32
 102 #endif
 103
 104 #if defined(__x86_64__)
 105 #define MATCH_MACHINE(x) (x == EM_X86_64)
 106 #define ELFCLASSM       ELFCLASS64
 107 #endif
 108
 109 #if defined(__microblaze__)
 110 #define MATCH_MACHINE(x) (x == EM_MICROBLAZE_OLD)
 111 #define ELFCLASSM       ELFCLASS32
 112 #endif
 113
 114 #if defined(__xtensa__)
 115 #define MATCH_MACHINE(x) (x == EM_XTENSA)
 116 #define ELFCLASSM       ELFCLASS32
 117 #endif
 118
 119 #ifndef MATCH_MACHINE
 120 # ifdef __linux__
 121 #  include <asm/elf.h>
 122 # endif
 123 # ifdef ELF_ARCH
 124 #  define MATCH_MACHINE(x) (x == ELF_ARCH)
 125 # endif
 126 # ifdef ELF_CLASS
 127 #  define ELFCLASSM ELF_CLASS
 128 # endif
 129 #endif
 130 #ifndef MATCH_MACHINE
 131 # warning "You really should add a MATCH_MACHINE() macro for your architecture"
 132 #endif
 133
 134 #if UCLIBC_ENDIAN_HOST == UCLIBC_ENDIAN_LITTLE
 135 #define ELFDATAM        ELFDATA2LSB
 136 #elif UCLIBC_ENDIAN_HOST == UCLIBC_ENDIAN_BIG
 137 #define ELFDATAM        ELFDATA2MSB
 138 #endif
 139
 140 #define TRUSTED_LDSO    UCLIBC_RUNTIME_PREFIX "lib/" UCLIBC_LDSO
 141
 142 struct library {
 143         char *name;
 144         int resolved;
 145         char *path;
 146         struct library *next;
 147 };
 148 static struct library *lib_list = NULL;
 149 static char not_found[] = "not found";
 150 static char *interp_name = NULL;
 151 static char *interp_dir = NULL;
 152 static int byteswap;
 153 static int interpreter_already_found = 0;
 154
 155 static __inline__ uint32_t byteswap32_to_host(uint32_t value)
 156 {
 157         if (byteswap) {
 158                 return (bswap_32(value));
 159         } else {
 160                 return (value);
 161         }
 162 }
 163 static __inline__ uint64_t byteswap64_to_host(uint64_t value)
 164 {
 165         if (byteswap) {
 166                 return (bswap_64(value));
 167         } else {
 168                 return (value);
 169         }
 170 }
 171
 172 #if __WORDSIZE == 64
 173 # define byteswap_to_host(x) byteswap64_to_host(x)
 174 #else
 175 # define byteswap_to_host(x) byteswap32_to_host(x)
 176 #endif
 177
 178 static ElfW(Shdr) *elf_find_section_type(uint32_t key, ElfW(Ehdr) *ehdr)
 179 {
 180         int j;
 181         ElfW(Shdr) *shdr;
 182         shdr = (ElfW(Shdr) *) (ehdr->e_shoff + (char *)ehdr);
 183         for (j = ehdr->e_shnum; --j >= 0; ++shdr) {
 184                 if (key == byteswap32_to_host(shdr->sh_type)) {
 185                         return shdr;
 186                 }
 187         }
 188         return NULL;
 189 }
 190
 191 static ElfW(Phdr) *elf_find_phdr_type(uint32_t type, ElfW(Ehdr) *ehdr)
 192 {
 193         int j;
 194         ElfW(Phdr) *phdr = (ElfW(Phdr) *) (ehdr->e_phoff + (char *)ehdr);
 195         for (j = ehdr->e_phnum; --j >= 0; ++phdr) {
 196                 if (type == byteswap32_to_host(phdr->p_type)) {
 197                         return phdr;
 198                 }
 199         }
 200         return NULL;
 201 }
 202
 203 /* Returns value if return_val==1, ptr otherwise */
 204 static void *elf_find_dynamic(int64_t const key, ElfW(Dyn) *dynp,
 205                        ElfW(Ehdr) *ehdr, int return_val)
 206 {
 207         ElfW(Phdr) *pt_text = elf_find_phdr_type(PT_LOAD, ehdr);
 208         unsigned tx_reloc = byteswap_to_host(pt_text->p_vaddr) - byteswap_to_host(pt_text->p_offset);
 209         for (; DT_NULL != byteswap_to_host(dynp->d_tag); ++dynp) {
 210                 if (key == byteswap_to_host(dynp->d_tag)) {
 211                         if (return_val == 1)
 212                                 return (void *)byteswap_to_host(dynp->d_un.d_val);
 213                         else
 214                                 return (void *)(byteswap_to_host(dynp->d_un.d_val) - tx_reloc + (char *)ehdr);
 215                 }
 216         }
 217         return NULL;
 218 }
 219
 220 static char *elf_find_rpath(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic)
 221 {
 222         ElfW(Dyn) *dyns;
 223
 224         for (dyns = dynamic; byteswap_to_host(dyns->d_tag) != DT_NULL; ++dyns) {
 225                 if (DT_RPATH == byteswap_to_host(dyns->d_tag)) {
 226                         char *strtab;
 227                         strtab = (char *)elf_find_dynamic(DT_STRTAB, dynamic, ehdr, 0);
 228                         return ((char *)strtab + byteswap_to_host(dyns->d_un.d_val));
 229                 }
 230         }
 231         return NULL;
 232 }
 233
 234 static int check_elf_header(ElfW(Ehdr) *const ehdr)
 235 {
 236         if (!ehdr || *(uint32_t*)ehdr != ELFMAG_U32
 237          /* Use __WORDSIZE, not ELFCLASSM which depends on the host */
 238          || ehdr->e_ident[EI_CLASS] != (__WORDSIZE >> 5)
 239          || ehdr->e_ident[EI_VERSION] != EV_CURRENT
 240         ) {
 241                 return 1;
 242         }
 243
 244         /* Check if the target endianness matches the host's endianness */
 245         byteswap = !(ehdr->e_ident[5] == ELFDATAM);
 246
 247         /* Be very lazy, and only byteswap the stuff we use */
 248         if (byteswap) {
 249                 ehdr->e_type = bswap_16(ehdr->e_type);
 250                 ehdr->e_phoff = byteswap_to_host(ehdr->e_phoff);
 251                 ehdr->e_shoff = byteswap_to_host(ehdr->e_shoff);
 252                 ehdr->e_phnum = bswap_16(ehdr->e_phnum);
 253                 ehdr->e_shnum = bswap_16(ehdr->e_shnum);
 254         }
 255
 256         return 0;
 257 }
 258
 259 #ifdef __LDSO_CACHE_SUPPORT__
 260 static caddr_t cache_addr = NULL;
 261 static size_t cache_size = 0;
 262
 263 static int map_cache(void)
 264 {
 265         int fd;
 266         struct stat st;
 267         header_t *header;
 268         libentry_t *libent;
 269         int i, strtabsize;
 270
 271         if (cache_addr == (caddr_t) - 1)
 272                 return -1;
 273         else if (cache_addr != NULL)
 274                 return 0;
 275
 276         if (stat(LDSO_CACHE, &st) || (fd = open(LDSO_CACHE, O_RDONLY)) < 0) {
 277                 fprintf(stderr, "ldd: can't open cache '%s'\n", LDSO_CACHE);
 278                 cache_addr = (caddr_t) - 1;     /* so we won't try again */
 279                 return -1;
 280         }
 281
 282         cache_size = st.st_size;
 283         cache_addr = mmap(0, cache_size, PROT_READ, MAP_SHARED, fd, 0);
 284         close(fd);
 285         if (cache_addr == MAP_FAILED) {
 286                 fprintf(stderr, "ldd: can't map cache '%s'\n", LDSO_CACHE);
 287                 return -1;
 288         }
 289
 290         header = (header_t *) cache_addr;
 291
 292         if (cache_size < sizeof(header_t)
 293             || memcmp(header->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN)
 294             || memcmp(header->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN)
 295             || cache_size < (sizeof(header_t) + header->nlibs * sizeof(libentry_t))
 296             || cache_addr[cache_size - 1] != '\0')
 297         {
 298                 fprintf(stderr, "ldd: cache '%s' is corrupt\n", LDSO_CACHE);
 299                 goto fail;
 300         }
 301
 302         strtabsize = cache_size - sizeof(header_t) - header->nlibs * sizeof(libentry_t);
 303         libent = (libentry_t *) & header[1];
 304
 305         for (i = 0; i < header->nlibs; i++) {
 306                 if (libent[i].sooffset >= strtabsize || libent[i].liboffset >= strtabsize) {
 307                         fprintf(stderr, "ldd: cache '%s' is corrupt\n", LDSO_CACHE);
 308                         goto fail;
 309                 }
 310         }
 311
 312         return 0;
 313
 314 fail:
 315         munmap(cache_addr, cache_size);
 316         cache_addr = (caddr_t) - 1;
 317         return -1;
 318 }
 319
 320 static int unmap_cache(void)
 321 {
 322         if (cache_addr == NULL || cache_addr == (caddr_t) - 1)
 323                 return -1;
 324
 325 #if 1
 326         munmap(cache_addr, cache_size);
 327         cache_addr = NULL;
 328 #endif
 329
 330         return 0;
 331 }
 332 #else
 333 static __inline__ void map_cache(void)
 334 {
 335 }
 336 static __inline__ void unmap_cache(void)
 337 {
 338 }
 339 #endif
 340
 341 /* This function's behavior must exactly match that
 342  * in uClibc/ldso/ldso/dl-elf.c */
 343 static void search_for_named_library(char *name, char *result,
 344                                      const char *path_list)
 345 {
 346         int i, count = 1;
 347         char *path, *path_n;
 348         struct stat filestat;
 349
 350         /* We need a writable copy of this string */
 351         path = strdup(path_list);
 352         if (!path) {
 353                 fprintf(stderr, "%s: Out of memory!\n", __func__);
 354                 exit(EXIT_FAILURE);
 355         }
 356         /* Eliminate all double //s */
 357         path_n = path;
 358         while ((path_n = strstr(path_n, "//"))) {
 359                 i = strlen(path_n);
 360                 memmove(path_n, path_n + 1, i - 1);
 361                 *(path_n + i - 1) = '\0';
 362         }
 363
 364         /* Replace colons with zeros in path_list and count them */
 365         for (i = strlen(path); i > 0; i--) {
 366                 if (path[i] == ':') {
 367                         path[i] = 0;
 368                         count++;
 369                 }
 370         }
 371         path_n = path;
 372         for (i = 0; i < count; i++) {
 373                 strcpy(result, path_n);
 374                 strcat(result, "/");
 375                 strcat(result, name);
 376                 if (stat(result, &filestat) == 0 && filestat.st_mode & S_IRUSR) {
 377                         free(path);
 378                         return;
 379                 }
 380                 path_n += (strlen(path_n) + 1);
 381         }
 382         free(path);
 383         *result = '\0';
 384 }
 385
 386 static void locate_library_file(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic,
 387                                 int is_suid, struct library *lib)
 388 {
 389         char *buf;
 390         char *path;
 391         struct stat filestat;
 392
 393         /* If this is a fully resolved name, our job is easy */
 394         if (stat(lib->name, &filestat) == 0) {
 395                 lib->path = strdup(lib->name);
 396                 return;
 397         }
 398
 399         /* We need some elbow room here.  Make some room... */
 400         buf = malloc(1024);
 401         if (!buf) {
 402                 fprintf(stderr, "%s: Out of memory!\n", __func__);
 403                 exit(EXIT_FAILURE);
 404         }
 405
 406         /* This function must match the behavior of _dl_load_shared_library
 407          * in readelflib1.c or things won't work out as expected... */
 408
 409         /* The ABI specifies that RPATH is searched first, so do that now.  */
 410         path = elf_find_rpath(ehdr, dynamic);
 411         if (path) {
 412                 search_for_named_library(lib->name, buf, path);
 413                 if (*buf != '\0') {
 414                         lib->path = buf;
 415                         return;
 416                 }
 417         }
 418
 419         /* Next check LD_{ELF_}LIBRARY_PATH if specified and allowed.
 420          * Since this app doesn't actually run an executable I will skip
 421          * the suid check, and just use LD_{ELF_}LIBRARY_PATH if set */
 422         if (is_suid == 1)
 423                 path = NULL;
 424         else
 425                 path = getenv("LD_LIBRARY_PATH");
 426         if (path) {
 427                 search_for_named_library(lib->name, buf, path);
 428                 if (*buf != '\0') {
 429                         lib->path = buf;
 430                         return;
 431                 }
 432         }
 433 #ifdef __LDSO_CACHE_SUPPORT__
 434         if (cache_addr != NULL && cache_addr != (caddr_t) - 1) {
 435                 int i;
 436                 header_t *header = (header_t *) cache_addr;
 437                 libentry_t *libent = (libentry_t *) & header[1];
 438                 char *strs = (char *)&libent[header->nlibs];
 439
 440                 for (i = 0; i < header->nlibs; i++) {
 441                         if ((libent[i].flags == LIB_ELF ||
 442                              libent[i].flags == LIB_ELF_LIBC0 ||
 443                              libent[i].flags == LIB_ELF_LIBC5) &&
 444                             strcmp(lib->name, strs + libent[i].sooffset) == 0)
 445                         {
 446                                 lib->path = strdup(strs + libent[i].liboffset);
 447                                 return;
 448                         }
 449                 }
 450         }
 451 #endif
 452
 453         /* Next look for libraries wherever the shared library
 454          * loader was installed -- this is usually where we
 455          * should find things... */
 456         if (interp_dir) {
 457                 search_for_named_library(lib->name, buf, interp_dir);
 458                 if (*buf != '\0') {
 459                         lib->path = buf;
 460                         return;
 461                 }
 462         }
 463
 464         /* Lastly, search the standard list of paths for the library.
 465            This list must exactly match the list in uClibc/ldso/ldso/dl-elf.c */
 466         path = UCLIBC_RUNTIME_PREFIX "lib:" UCLIBC_RUNTIME_PREFIX "usr/lib"
 467 #ifndef __LDSO_CACHE_SUPPORT__
 468             ":" UCLIBC_RUNTIME_PREFIX "usr/X11R6/lib"
 469 #endif
 470             ;
 471         search_for_named_library(lib->name, buf, path);
 472         if (*buf != '\0') {
 473                 lib->path = buf;
 474         } else {
 475                 free(buf);
 476                 lib->path = not_found;
 477         }
 478 }
 479
 480 static int add_library(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic, int is_setuid, char *s)
 481 {
 482         char *tmp, *tmp1, *tmp2;
 483         struct library *cur, *newlib = lib_list;
 484
 485         if (!s || !strlen(s))
 486                 return 1;
 487
 488         tmp = s;
 489         while (*tmp) {
 490                 if (*tmp == '/')
 491                         s = tmp + 1;
 492                 tmp++;
 493         }
 494
 495         /* We add ldso elsewhere */
 496         if (interpreter_already_found && (tmp = strrchr(interp_name, '/')) != NULL) {
 497                 int len = strlen(interp_dir);
 498                 if (strcmp(s, interp_name + 1 + len) == 0)
 499                         return 1;
 500         }
 501
 502         for (cur = lib_list; cur; cur = cur->next) {
 503                 /* Check if this library is already in the list */
 504                 tmp1 = tmp2 = cur->name;
 505                 if (!cur->name)
 506                         continue;
 507                 while (*tmp1) {
 508                         if (*tmp1 == '/')
 509                                 tmp2 = tmp1 + 1;
 510                         tmp1++;
 511                 }
 512                 if (strcmp(tmp2, s) == 0) {
 513                         /*printf("find_elf_interpreter is skipping '%s' (already in list)\n", cur->name); */
 514                         return 0;
 515                 }
 516         }
 517
 518         /* Ok, this lib needs to be added to the list */
 519         newlib = malloc(sizeof(struct library));
 520         if (!newlib)
 521                 return 1;
 522         newlib->name = malloc(strlen(s) + 1);
 523         strcpy(newlib->name, s);
 524         newlib->resolved = 0;
 525         newlib->path = NULL;
 526         newlib->next = NULL;
 527
 528         /* Now try and locate where this library might be living... */
 529         locate_library_file(ehdr, dynamic, is_setuid, newlib);
 530
 531         /*printf("add_library is adding '%s' to '%s'\n", newlib->name, newlib->path); */
 532         if (!lib_list) {
 533                 lib_list = newlib;
 534         } else {
 535                 for (cur = lib_list; cur->next; cur = cur->next) ;      /* nothing */
 536                 cur->next = newlib;
 537         }
 538         return 0;
 539 }
 540
 541 static void find_needed_libraries(ElfW(Ehdr) *ehdr, ElfW(Dyn) *dynamic, int is_setuid)
 542 {
 543         ElfW(Dyn) *dyns;
 544
 545         for (dyns = dynamic; byteswap_to_host(dyns->d_tag) != DT_NULL; ++dyns) {
 546                 if (DT_NEEDED == byteswap_to_host(dyns->d_tag)) {
 547                         char *strtab;
 548                         strtab = (char *)elf_find_dynamic(DT_STRTAB, dynamic, ehdr, 0);
 549                         add_library(ehdr, dynamic, is_setuid, (char *)strtab + byteswap_to_host(dyns->d_un.d_val));
 550                 }
 551         }
 552 }
 553
 554 #ifdef __LDSO_LDD_SUPPORT__
 555 static struct library *find_elf_interpreter(ElfW(Ehdr) *ehdr)
 556 {
 557         ElfW(Phdr) *phdr;
 558
 559         if (interpreter_already_found == 1)
 560                 return NULL;
 561         phdr = elf_find_phdr_type(PT_INTERP, ehdr);
 562         if (phdr) {
 563                 struct library *cur, *newlib = NULL;
 564                 char *s = (char *)ehdr + byteswap_to_host(phdr->p_offset);
 565
 566                 char *tmp, *tmp1;
 567                 interp_name = strdup(s);
 568                 interp_dir = strdup(s);
 569                 tmp = strrchr(interp_dir, '/');
 570                 if (tmp)
 571                         *tmp = '\0';
 572                 else {
 573                         free(interp_dir);
 574                         interp_dir = interp_name;
 575                 }
 576                 tmp1 = tmp = s;
 577                 while (*tmp) {
 578                         if (*tmp == '/')
 579                                 tmp1 = tmp + 1;
 580                         tmp++;
 581                 }
 582                 for (cur = lib_list; cur; cur = cur->next) {
 583                         /* Check if this library is already in the list */
 584                         if (!tmp1 || !cur->name)
 585                                 return NULL;
 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 }