ldso/libdl/libdl.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Program to load an ELF binary on a linux system, and run it
   4  * after resolving ELF shared library symbols
   5  *
   6  * Copyright (C) 2000-2006 by Erik Andersen <andersen@uclibc.org>
   7  * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
   8  *                              David Engel, Hongjiu Lu and Mitch D'Souza
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. The name of the above contributors may not be
  16  *    used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32
  33 #include <ldso.h>
  34 #include <stdio.h>
  35 #include <string.h> /* Needed for 'strstr' prototype' */
  36 #include <stdbool.h>
  37
  38
  39 #ifdef SHARED
  40
  41 /* When libdl is loaded as a shared library, we need to load in
  42  * and use a pile of symbols from ldso... */
  43
  44 extern char *_dl_find_hash(const char *, struct dyn_elf *, struct elf_resolve *, int);
  45 extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **,
  46         struct elf_resolve *, char *, int);
  47 extern int _dl_fixup(struct dyn_elf *rpnt, int lazy);
  48 extern void _dl_protect_relro(struct elf_resolve * tpnt);
  49 extern int _dl_errno;
  50 extern struct dyn_elf *_dl_symbol_tables;
  51 extern struct dyn_elf *_dl_handles;
  52 extern struct elf_resolve *_dl_loaded_modules;
  53 extern struct r_debug *_dl_debug_addr;
  54 extern unsigned long _dl_error_number;
  55 extern void *(*_dl_malloc_function)(size_t);
  56 extern void (*_dl_free_function) (void *p);
  57 extern void _dl_run_init_array(struct elf_resolve *);
  58 extern void _dl_run_fini_array(struct elf_resolve *);
  59 #ifdef __LDSO_CACHE_SUPPORT__
  60 int _dl_map_cache(void);
  61 int _dl_unmap_cache(void);
  62 #endif
  63 #ifdef __mips__
  64 extern void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt, int lazy);
  65 #endif
  66 #ifdef __SUPPORT_LD_DEBUG__
  67 extern char *_dl_debug;
  68 #endif
  69
  70
  71 #else /* SHARED */
  72
  73 #define _dl_malloc malloc
  74 #define _dl_free free
  75
  76 /* When libdl is linked as a static library, we need to replace all
  77  * the symbols that otherwise would have been loaded in from ldso... */
  78
  79 #ifdef __SUPPORT_LD_DEBUG__
  80 char *_dl_debug  = 0;
  81 char *_dl_debug_symbols   = 0;
  82 char *_dl_debug_move      = 0;
  83 char *_dl_debug_reloc     = 0;
  84 char *_dl_debug_detail    = 0;
  85 char *_dl_debug_nofixups  = 0;
  86 char *_dl_debug_bindings  = 0;
  87 int   _dl_debug_file      = 2;
  88 #endif
  89 const char *_dl_progname       = "";        /* Program name */
  90 void *(*_dl_malloc_function)(size_t);
  91 void (*_dl_free_function) (void *p);
  92 char *_dl_library_path         = 0;         /* Where we look for libraries */
  93 char *_dl_ldsopath             = 0;         /* Location of the shared lib loader */
  94 int _dl_errno                  = 0;         /* We can't use the real errno in ldso */
  95 size_t _dl_pagesize            = PAGE_SIZE; /* Store the page size for use later */
  96 /* This global variable is also to communicate with debuggers such as gdb. */
  97 struct r_debug *_dl_debug_addr = NULL;
  98
  99 #include "../ldso/dl-array.c"
 100 #include "../ldso/dl-debug.c"
 101 #include LDSO_ELFINTERP
 102 #include "../ldso/dl-hash.c"
 103 #define _dl_trace_loaded_objects    0
 104 #include "../ldso/dl-elf.c"
 105 #endif /* SHARED */
 106
 107 #ifdef __SUPPORT_LD_DEBUG__
 108 # define _dl_if_debug_print(fmt, args...) \
 109         do { \
 110         if (_dl_debug) \
 111                 fprintf(stderr, "%s():%i: " fmt, __FUNCTION__, __LINE__, ## args); \
 112         } while (0)
 113 #else
 114 # define _dl_if_debug_print(fmt, args...)
 115 #endif
 116
 117 static int do_dlclose(void *, int need_fini);
 118
 119
 120 static const char *dl_error_names[] = {
 121         "",
 122         "File not found",
 123         "Unable to open /dev/zero",
 124         "Not an ELF file",
 125 #if defined (__i386__)
 126         "Not i386 binary",
 127 #elif defined (__sparc__)
 128         "Not sparc binary",
 129 #elif defined (__mc68000__)
 130         "Not m68k binary",
 131 #else
 132         "Unrecognized binary type",
 133 #endif
 134         "Not an ELF shared library",
 135         "Unable to mmap file",
 136         "No dynamic section",
 137 #ifdef ELF_USES_RELOCA
 138         "Unable to process REL relocs",
 139 #else
 140         "Unable to process RELA relocs",
 141 #endif
 142         "Bad handle",
 143         "Unable to resolve symbol"
 144 };
 145
 146 void dl_cleanup(void) __attribute__ ((destructor));
 147 void dl_cleanup(void)
 148 {
 149         struct dyn_elf *d;
 150         for (d = _dl_handles; d; d = d->next_handle) {
 151                 do_dlclose(d, 1);
 152         }
 153 }
 154
 155 void *dlopen(const char *libname, int flag)
 156 {
 157         struct elf_resolve *tpnt, *tfrom;
 158         struct dyn_elf *dyn_chain, *rpnt = NULL, *dyn_ptr, *relro_ptr, *handle;
 159         ElfW(Addr) from;
 160         struct elf_resolve *tpnt1;
 161         void (*dl_brk) (void);
 162         int now_flag;
 163         struct init_fini_list *tmp, *runp, *runp2, *dep_list;
 164         unsigned int nlist, i;
 165         struct elf_resolve **init_fini_list;
 166         static bool _dl_init;
 167
 168         /* A bit of sanity checking... */
 169         if (!(flag & (RTLD_LAZY|RTLD_NOW))) {
 170                 _dl_error_number = LD_BAD_HANDLE;
 171                 return NULL;
 172         }
 173
 174         from = (ElfW(Addr)) __builtin_return_address(0);
 175
 176         if (!_dl_init) {
 177                 _dl_init = true;
 178                 _dl_malloc_function = malloc;
 179                 _dl_free_function = free;
 180         }
 181         /* Cover the trivial case first */
 182         if (!libname)
 183                 return _dl_symbol_tables;
 184
 185 #ifndef SHARED
 186 # ifdef __SUPPORT_LD_DEBUG__
 187         _dl_debug = getenv("LD_DEBUG");
 188         if (_dl_debug) {
 189                 if (_dl_strstr(_dl_debug, "all")) {
 190                         _dl_debug_detail = _dl_debug_move = _dl_debug_symbols
 191                                 = _dl_debug_reloc = _dl_debug_bindings = _dl_debug_nofixups = (void*)1;
 192                 } else {
 193                         _dl_debug_detail   = strstr(_dl_debug, "detail");
 194                         _dl_debug_move     = strstr(_dl_debug, "move");
 195                         _dl_debug_symbols  = strstr(_dl_debug, "sym");
 196                         _dl_debug_reloc    = strstr(_dl_debug, "reloc");
 197                         _dl_debug_nofixups = strstr(_dl_debug, "nofix");
 198                         _dl_debug_bindings = strstr(_dl_debug, "bind");
 199                 }
 200         }
 201 # endif
 202 #endif
 203
 204         _dl_map_cache();
 205
 206         /*
 207          * Try and locate the module we were called from - we
 208          * need this so that we get the correct RPATH/RUNPATH.  Note that
 209          * this is the current behavior under Solaris, but the
 210          * ABI+ specifies that we should only use the RPATH from
 211          * the application.  Thus this may go away at some time
 212          * in the future.
 213          */
 214         {
 215                 struct dyn_elf *dpnt;
 216                 tfrom = NULL;
 217                 for (dpnt = _dl_symbol_tables; dpnt; dpnt = dpnt->next) {
 218                         tpnt = dpnt->dyn;
 219                         if (DL_ADDR_IN_LOADADDR(from, tpnt, tfrom))
 220                                 tfrom = tpnt;
 221                 }
 222         }
 223         for (rpnt = _dl_symbol_tables; rpnt && rpnt->next; rpnt=rpnt->next);
 224
 225         relro_ptr = rpnt;
 226         now_flag = (flag & RTLD_NOW) ? RTLD_NOW : 0;
 227         if (getenv("LD_BIND_NOW"))
 228                 now_flag = RTLD_NOW;
 229
 230 #ifndef SHARED
 231         /* When statically linked, the _dl_library_path is not yet initialized */
 232         _dl_library_path = getenv("LD_LIBRARY_PATH");
 233 #endif
 234
 235         /* Try to load the specified library */
 236         _dl_if_debug_print("Trying to dlopen '%s', RTLD_GLOBAL:%d RTLD_NOW:%d\n",
 237                         (char*)libname, (flag & RTLD_GLOBAL ? 1:0), (now_flag & RTLD_NOW ? 1:0));
 238         tpnt = _dl_load_shared_library(0, &rpnt, tfrom, (char*)libname, 0);
 239
 240         if (tpnt == NULL) {
 241                 _dl_unmap_cache();
 242                 return NULL;
 243         }
 244         dyn_chain = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
 245         _dl_memset(dyn_chain, 0, sizeof(struct dyn_elf));
 246         dyn_chain->dyn = tpnt;
 247         tpnt->rtld_flags |= (flag & RTLD_GLOBAL);
 248
 249         dyn_chain->next_handle = _dl_handles;
 250         _dl_handles = dyn_ptr = dyn_chain;
 251
 252         if (tpnt->usage_count > 1) {
 253                 _dl_if_debug_print("Lib: %s already opened\n", libname);
 254                 /* see if there is a handle from a earlier dlopen */
 255                 for (handle = _dl_handles->next_handle; handle; handle = handle->next_handle) {
 256                         if (handle->dyn == tpnt) {
 257                                 dyn_chain->init_fini.init_fini = handle->init_fini.init_fini;
 258                                 dyn_chain->init_fini.nlist = handle->init_fini.nlist;
 259                                 for (i = 0; i < dyn_chain->init_fini.nlist; i++)
 260                                         dyn_chain->init_fini.init_fini[i]->rtld_flags |= (flag & RTLD_GLOBAL);
 261                                 dyn_chain->next = handle->next;
 262                                 break;
 263                         }
 264                 }
 265                 return dyn_chain;
 266         } else {
 267                 tpnt->init_flag |= DL_OPENED;
 268         }
 269
 270         _dl_if_debug_print("Looking for needed libraries\n");
 271         nlist = 0;
 272         runp = alloca(sizeof(*runp));
 273         runp->tpnt = tpnt;
 274         runp->next = NULL;
 275         dep_list = runp2 = runp;
 276         for (; runp; runp = runp->next)
 277         {
 278                 ElfW(Dyn) *dpnt;
 279                 char *lpntstr;
 280
 281                 nlist++;
 282                 runp->tpnt->init_fini = NULL; /* clear any previous dependcies */
 283                 for (dpnt = (ElfW(Dyn) *) runp->tpnt->dynamic_addr; dpnt->d_tag; dpnt++) {
 284                         if (dpnt->d_tag == DT_NEEDED) {
 285                                 lpntstr = (char*) (runp->tpnt->dynamic_info[DT_STRTAB] +
 286                                                 dpnt->d_un.d_val);
 287                                 _dl_if_debug_print("Trying to load '%s', needed by '%s'\n",
 288                                                 lpntstr, runp->tpnt->libname);
 289                                 tpnt1 = _dl_load_shared_library(0, &rpnt, runp->tpnt, lpntstr, 0);
 290                                 if (!tpnt1)
 291                                         goto oops;
 292
 293                                 tpnt1->rtld_flags |= (flag & RTLD_GLOBAL);
 294
 295                                 /* This list is for dlsym() and relocation */
 296                                 dyn_ptr->next = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
 297                                 _dl_memset (dyn_ptr->next, 0, sizeof (struct dyn_elf));
 298                                 dyn_ptr = dyn_ptr->next;
 299                                 dyn_ptr->dyn = tpnt1;
 300                                 /* Used to record RTLD_LOCAL scope */
 301                                 tmp = alloca(sizeof(struct init_fini_list));
 302                                 tmp->tpnt = tpnt1;
 303                                 tmp->next = runp->tpnt->init_fini;
 304                                 runp->tpnt->init_fini = tmp;
 305
 306                                 for (tmp=dep_list; tmp; tmp = tmp->next) {
 307                                         if (tpnt1 == tmp->tpnt) { /* if match => cirular dependency, drop it */
 308                                                 _dl_if_debug_print("Circular dependency, skipping '%s',\n",
 309                                                                    tmp->tpnt->libname);
 310                                                 tpnt1->usage_count--;
 311                                                 break;
 312                                         }
 313                                 }
 314                                 if (!tmp) { /* Don't add if circular dependency detected */
 315                                         runp2->next = alloca(sizeof(*runp));
 316                                         runp2 = runp2->next;
 317                                         runp2->tpnt = tpnt1;
 318                                         runp2->next = NULL;
 319                                 }
 320                         }
 321                 }
 322         }
 323         init_fini_list = malloc(nlist * sizeof(struct elf_resolve *));
 324         dyn_chain->init_fini.init_fini = init_fini_list;
 325         dyn_chain->init_fini.nlist = nlist;
 326         i = 0;
 327         for (runp2 = dep_list; runp2; runp2 = runp2->next) {
 328                 init_fini_list[i++] = runp2->tpnt;
 329                 for (runp = runp2->tpnt->init_fini; runp; runp = runp->next) {
 330                         if (!(runp->tpnt->rtld_flags & RTLD_GLOBAL)) {
 331                                 tmp = malloc(sizeof(struct init_fini_list));
 332                                 tmp->tpnt = runp->tpnt;
 333                                 tmp->next = runp2->tpnt->rtld_local;
 334                                 runp2->tpnt->rtld_local = tmp;
 335                         }
 336                 }
 337
 338         }
 339         /* Sort the INIT/FINI list in dependency order. */
 340         for (runp2 = dep_list; runp2; runp2 = runp2->next) {
 341                 unsigned int j, k;
 342                 for (j = 0; init_fini_list[j] != runp2->tpnt; ++j)
 343                         /* Empty */;
 344                 for (k = j + 1; k < nlist; ++k) {
 345                         struct init_fini_list *ele = init_fini_list[k]->init_fini;
 346
 347                         for (; ele; ele = ele->next) {
 348                                 if (ele->tpnt == runp2->tpnt) {
 349                                         struct elf_resolve *here = init_fini_list[k];
 350                                         _dl_if_debug_print("Move %s from pos %d to %d in INIT/FINI list.\n", here->libname, k, j);
 351                                         for (i = (k - j); i; --i)
 352                                                 init_fini_list[i+j] = init_fini_list[i+j-1];
 353                                         init_fini_list[j] = here;
 354                                         ++j;
 355                                         break;
 356                                 }
 357                         }
 358                 }
 359         }
 360 #ifdef __SUPPORT_LD_DEBUG__
 361         if (_dl_debug) {
 362                 fprintf(stderr, "\nINIT/FINI order and dependencies:\n");
 363                 for (i = 0; i < nlist; i++) {
 364                         fprintf(stderr, "lib: %s has deps:\n", init_fini_list[i]->libname);
 365                         runp = init_fini_list[i]->init_fini;
 366                         for (; runp; runp = runp->next)
 367                                 printf(" %s ", runp->tpnt->libname);
 368                         printf("\n");
 369                 }
 370         }
 371 #endif
 372
 373         _dl_if_debug_print("Beginning dlopen relocation fixups\n");
 374         /*
 375          * OK, now all of the kids are tucked into bed in their proper addresses.
 376          * Now we go through and look for REL and RELA records that indicate fixups
 377          * to the GOT tables.  We need to do this in reverse order so that COPY
 378          * directives work correctly */
 379 #ifdef __mips__
 380         /*
 381          * Relocation of the GOT entries for MIPS have to be done
 382          * after all the libraries have been loaded.
 383          */
 384         _dl_perform_mips_global_got_relocations(tpnt, !now_flag);
 385 #endif
 386
 387         if (_dl_fixup(dyn_chain, now_flag))
 388                 goto oops;
 389
 390         if (relro_ptr) {
 391                 for (rpnt = relro_ptr->next; rpnt; rpnt = rpnt->next) {
 392                         if (rpnt->dyn->relro_size)
 393                                 _dl_protect_relro(rpnt->dyn);
 394                 }
 395         }
 396         /* TODO:  Should we set the protections of all pages back to R/O now ? */
 397
 398
 399         /* Notify the debugger we have added some objects. */
 400         if (_dl_debug_addr) {
 401                 dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
 402                 if (dl_brk != NULL) {
 403                         _dl_debug_addr->r_state = RT_ADD;
 404                         (*dl_brk) ();
 405
 406                         _dl_debug_addr->r_state = RT_CONSISTENT;
 407                         (*dl_brk) ();
 408                 }
 409         }
 410
 411         /* Run the ctors and setup the dtors */
 412         for (i = nlist; i; --i) {
 413                 tpnt = init_fini_list[i-1];
 414                 if (tpnt->init_flag & INIT_FUNCS_CALLED)
 415                         continue;
 416                 tpnt->init_flag |= INIT_FUNCS_CALLED;
 417
 418                 if (tpnt->dynamic_info[DT_INIT]) {
 419                         void (*dl_elf_func) (void);
 420                         dl_elf_func = (void (*)(void)) DL_RELOC_ADDR(tpnt->loadaddr, tpnt->dynamic_info[DT_INIT]);
 421                         if (dl_elf_func) {
 422                                 _dl_if_debug_print("running ctors for library %s at '%p'\n",
 423                                                 tpnt->libname, dl_elf_func);
 424                                 DL_CALL_FUNC_AT_ADDR (dl_elf_func, tpnt->loadaddr, (void(*)(void)));
 425                         }
 426                 }
 427
 428                 _dl_run_init_array(tpnt);
 429         }
 430
 431         _dl_unmap_cache();
 432         return (void *) dyn_chain;
 433
 434 oops:
 435         /* Something went wrong.  Clean up and return NULL. */
 436         _dl_unmap_cache();
 437         do_dlclose(dyn_chain, 0);
 438         return NULL;
 439 }
 440
 441 void *dlsym(void *vhandle, const char *name)
 442 {
 443         struct elf_resolve *tpnt, *tfrom;
 444         struct dyn_elf *handle;
 445         ElfW(Addr) from;
 446         struct dyn_elf *rpnt;
 447         void *ret;
 448         /* Nastiness to support underscore prefixes.  */
 449 #ifdef __UCLIBC_UNDERSCORES__
 450         char tmp_buf[80];
 451         char *name2 = tmp_buf;
 452         size_t nlen = strlen (name) + 1;
 453         if (nlen + 1 > sizeof (tmp_buf))
 454             name2 = malloc (nlen + 1);
 455         if (name2 == 0) {
 456             _dl_error_number = LD_ERROR_MMAP_FAILED;
 457             return 0;
 458         }
 459         name2[0] = '_';
 460         memcpy (name2 + 1, name, nlen);
 461 #else
 462         const char *name2 = name;
 463 #endif
 464         handle = (struct dyn_elf *) vhandle;
 465
 466         /* First of all verify that we have a real handle
 467            of some kind.  Return NULL if not a valid handle. */
 468
 469         if (handle == NULL)
 470                 handle = _dl_symbol_tables;
 471         else if (handle != RTLD_NEXT && handle != _dl_symbol_tables) {
 472                 for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle)
 473                         if (rpnt == handle)
 474                                 break;
 475                 if (!rpnt) {
 476                         _dl_error_number = LD_BAD_HANDLE;
 477                         ret = NULL;
 478                         goto out;
 479                 }
 480         } else if (handle == RTLD_NEXT) {
 481                 /*
 482                  * Try and locate the module we were called from - we
 483                  * need this so that we know where to start searching
 484                  * from.  We never pass RTLD_NEXT down into the actual
 485                  * dynamic loader itself, as it doesn't know
 486                  * how to properly treat it.
 487                  */
 488                 from = (ElfW(Addr)) __builtin_return_address(0);
 489
 490                 tfrom = NULL;
 491                 for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next) {
 492                         tpnt = rpnt->dyn;
 493                         if (DL_ADDR_IN_LOADADDR(from, tpnt, tfrom)) {
 494                                 tfrom = tpnt;
 495                                 handle = rpnt->next;
 496                         }
 497                 }
 498         }
 499         tpnt = NULL;
 500         if (handle == _dl_symbol_tables)
 501            tpnt = handle->dyn; /* Only search RTLD_GLOBAL objs if global object */
 502         ret = _dl_find_hash(name2, handle, tpnt, ELF_RTYPE_CLASS_DLSYM);
 503
 504         /*
 505          * Nothing found.
 506          */
 507         if (!ret)
 508                 _dl_error_number = LD_NO_SYMBOL;
 509 out:
 510 #ifdef __UCLIBC_UNDERSCORES__
 511         if (name2 != tmp_buf)
 512                 free (name2);
 513 #endif
 514         return ret;
 515 }
 516
 517 #if 0
 518 void *dlvsym(void *vhandle, const char *name, const char *version)
 519 {
 520         return dlsym(vhandle, name);
 521 }
 522 #endif
 523
 524 static int do_dlclose(void *vhandle, int need_fini)
 525 {
 526         struct dyn_elf *rpnt, *rpnt1, *rpnt1_tmp;
 527         struct init_fini_list *runp, *tmp;
 528         ElfW(Phdr) *ppnt;
 529         struct elf_resolve *tpnt, *run_tpnt;
 530         int (*dl_elf_fini) (void);
 531         void (*dl_brk) (void);
 532         struct dyn_elf *handle;
 533         unsigned int end;
 534         unsigned int i, j;
 535
 536         handle = (struct dyn_elf *) vhandle;
 537         if (handle == _dl_symbol_tables)
 538                 return 0;
 539         rpnt1 = NULL;
 540         for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle) {
 541                 if (rpnt == handle)
 542                         break;
 543                 rpnt1 = rpnt;
 544         }
 545
 546         if (!rpnt) {
 547                 _dl_error_number = LD_BAD_HANDLE;
 548                 return 1;
 549         }
 550         if (rpnt1)
 551                 rpnt1->next_handle = rpnt->next_handle;
 552         else
 553                 _dl_handles = rpnt->next_handle;
 554         _dl_if_debug_print("%s: usage count: %d\n",
 555                         handle->dyn->libname, handle->dyn->usage_count);
 556         if (handle->dyn->usage_count != 1) {
 557                 handle->dyn->usage_count--;
 558                 free(handle);
 559                 return 0;
 560         }
 561         /* OK, this is a valid handle - now close out the file */
 562         for (j = 0; j < handle->init_fini.nlist; ++j) {
 563                 tpnt = handle->init_fini.init_fini[j];
 564                 if (--tpnt->usage_count == 0) {
 565                         if ((tpnt->dynamic_info[DT_FINI]
 566                              || tpnt->dynamic_info[DT_FINI_ARRAY])
 567                             && need_fini &&
 568                             !(tpnt->init_flag & FINI_FUNCS_CALLED)) {
 569                                 tpnt->init_flag |= FINI_FUNCS_CALLED;
 570                                 _dl_run_fini_array(tpnt);
 571
 572                                 if (tpnt->dynamic_info[DT_FINI]) {
 573                                         dl_elf_fini = (int (*)(void)) DL_RELOC_ADDR(tpnt->loadaddr, tpnt->dynamic_info[DT_FINI]);
 574                                         _dl_if_debug_print("running dtors for library %s at '%p'\n",
 575                                                         tpnt->libname, dl_elf_fini);
 576                                         DL_CALL_FUNC_AT_ADDR (dl_elf_fini, tpnt->loadaddr, (int (*)(void)));
 577                                 }
 578                         }
 579
 580                         _dl_if_debug_print("unmapping: %s\n", tpnt->libname);
 581                         end = 0;
 582                         for (i = 0, ppnt = tpnt->ppnt;
 583                                         i < tpnt->n_phent; ppnt++, i++) {
 584                                 if (ppnt->p_type != PT_LOAD)
 585                                         continue;
 586                                 if (end < ppnt->p_vaddr + ppnt->p_memsz)
 587                                         end = ppnt->p_vaddr + ppnt->p_memsz;
 588                         }
 589                         DL_LIB_UNMAP (tpnt, end);
 590                         /* Free elements in RTLD_LOCAL scope list */
 591                         for (runp = tpnt->rtld_local; runp; runp = tmp) {
 592                                 tmp = runp->next;
 593                                 free(runp);
 594                         }
 595
 596                         /* Next, remove tpnt from the loaded_module list */
 597                         if (_dl_loaded_modules == tpnt) {
 598                                 _dl_loaded_modules = tpnt->next;
 599                                 if (_dl_loaded_modules)
 600                                         _dl_loaded_modules->prev = 0;
 601                         } else
 602                                 for (run_tpnt = _dl_loaded_modules; run_tpnt; run_tpnt = run_tpnt->next)
 603                                         if (run_tpnt->next == tpnt) {
 604                                                 _dl_if_debug_print("removing loaded_modules: %s\n", tpnt->libname);
 605                                                 run_tpnt->next = run_tpnt->next->next;
 606                                                 if (run_tpnt->next)
 607                                                         run_tpnt->next->prev = run_tpnt;
 608                                                 break;
 609                                         }
 610
 611                         /* Next, remove tpnt from the global symbol table list */
 612                         if (_dl_symbol_tables) {
 613                                 if (_dl_symbol_tables->dyn == tpnt) {
 614                                         _dl_symbol_tables = _dl_symbol_tables->next;
 615                                         if (_dl_symbol_tables)
 616                                                 _dl_symbol_tables->prev = 0;
 617                                 } else
 618                                         for (rpnt1 = _dl_symbol_tables; rpnt1->next; rpnt1 = rpnt1->next) {
 619                                                 if (rpnt1->next->dyn == tpnt) {
 620                                                         _dl_if_debug_print("removing symbol_tables: %s\n", tpnt->libname);
 621                                                         rpnt1_tmp = rpnt1->next->next;
 622                                                         free(rpnt1->next);
 623                                                         rpnt1->next = rpnt1_tmp;
 624                                                         if (rpnt1->next)
 625                                                                 rpnt1->next->prev = rpnt1;
 626                                                         break;
 627                                                 }
 628                                         }
 629                         }
 630                         free(tpnt->libname);
 631                         free(tpnt);
 632                 }
 633         }
 634         free(handle->init_fini.init_fini);
 635         free(handle);
 636
 637
 638         if (_dl_debug_addr) {
 639                 dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
 640                 if (dl_brk != NULL) {
 641                         _dl_debug_addr->r_state = RT_DELETE;
 642                         (*dl_brk) ();
 643
 644                         _dl_debug_addr->r_state = RT_CONSISTENT;
 645                         (*dl_brk) ();
 646                 }
 647         }
 648
 649         return 0;
 650 }
 651
 652 int dlclose(void *vhandle)
 653 {
 654         return do_dlclose(vhandle, 1);
 655 }
 656
 657 char *dlerror(void)
 658 {
 659         const char *retval;
 660
 661         if (!_dl_error_number)
 662                 return NULL;
 663         retval = dl_error_names[_dl_error_number];
 664         _dl_error_number = 0;
 665         return (char *)retval;
 666 }
 667
 668 /*
 669  * Dump information to stderr about the current loaded modules
 670  */
 671 #ifdef __USE_GNU
 672 static char *type[] = { "Lib", "Exe", "Int", "Mod" };
 673
 674 int dlinfo(void)
 675 {
 676         struct elf_resolve *tpnt;
 677         struct dyn_elf *rpnt, *hpnt;
 678
 679         fprintf(stderr, "List of loaded modules\n");
 680         /* First start with a complete list of all of the loaded files. */
 681         for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 682                 fprintf(stderr, "\t%p %p %p %s %d %s\n",
 683                         DL_LOADADDR_BASE(tpnt->loadaddr), tpnt, tpnt->symbol_scope,
 684                         type[tpnt->libtype],
 685                         tpnt->usage_count, tpnt->libname);
 686         }
 687
 688         /* Next dump the module list for the application itself */
 689         fprintf(stderr, "\nModules for application (%p):\n", _dl_symbol_tables);
 690         for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next)
 691                 fprintf(stderr, "\t%p %s\n", rpnt->dyn, rpnt->dyn->libname);
 692
 693         for (hpnt = _dl_handles; hpnt; hpnt = hpnt->next_handle) {
 694                 fprintf(stderr, "Modules for handle %p\n", hpnt);
 695                 for (rpnt = hpnt; rpnt; rpnt = rpnt->next)
 696                         fprintf(stderr, "\t%p %s\n", rpnt->dyn, rpnt->dyn->libname);
 697         }
 698         return 0;
 699 }
 700
 701 int dladdr(const void *__address, Dl_info * __info)
 702 {
 703         struct elf_resolve *pelf;
 704         struct elf_resolve *rpnt;
 705
 706         _dl_map_cache();
 707
 708         /*
 709          * Try and locate the module address is in
 710          */
 711         pelf = NULL;
 712
 713         _dl_if_debug_print("__address: %p  __info: %p\n", __address, __info);
 714
 715         __address = DL_LOOKUP_ADDRESS (__address);
 716
 717         for (rpnt = _dl_loaded_modules; rpnt; rpnt = rpnt->next) {
 718                 struct elf_resolve *tpnt;
 719
 720                 tpnt = rpnt;
 721
 722                 _dl_if_debug_print("Module \"%s\" at %p\n",
 723                                    tpnt->libname, DL_LOADADDR_BASE(tpnt->loadaddr));
 724
 725                 if (DL_ADDR_IN_LOADADDR((ElfW(Addr)) __address, tpnt, pelf))
 726                         pelf = tpnt;
 727         }
 728
 729         if (!pelf) {
 730                 return 0;
 731         }
 732
 733         /*
 734          * Try and locate the symbol of address
 735          */
 736
 737         {
 738                 char *strtab;
 739                 ElfW(Sym) *symtab;
 740                 unsigned int hn, si, sn, sf;
 741                 ElfW(Addr) sa = 0;
 742
 743                 /* Set the info for the object the address lies in */
 744                 __info->dli_fname = pelf->libname;
 745                 __info->dli_fbase = (void *)pelf->mapaddr;
 746
 747                 symtab = (ElfW(Sym) *) (pelf->dynamic_info[DT_SYMTAB]);
 748                 strtab = (char *) (pelf->dynamic_info[DT_STRTAB]);
 749
 750                 sf = sn = 0;
 751
 752 #ifdef __LDSO_GNU_HASH_SUPPORT__
 753                 if (pelf->l_gnu_bitmask) {
 754                         for (hn = 0; hn < pelf->nbucket; hn++) {
 755                                 si = pelf->l_gnu_buckets[hn];
 756                                 if (!si)
 757                                         continue;
 758
 759                                 const Elf32_Word *hasharr = &pelf->l_gnu_chain_zero[si];
 760                                 do {
 761                                         ElfW(Addr) symbol_addr;
 762
 763                                         symbol_addr = (ElfW(Addr)) DL_RELOC_ADDR(pelf->loadaddr, symtab[si].st_value);
 764                                         if (symbol_addr <= (ElfW(Addr))__address && (!sf || sa < symbol_addr)) {
 765                                                 sa = symbol_addr;
 766                                                 sn = si;
 767                                                 sf = 1;
 768                                         }
 769                                         _dl_if_debug_print("Symbol \"%s\" at %p\n", strtab + symtab[si].st_name, symbol_addr);
 770                                         ++si;
 771                                 } while ((*hasharr++ & 1u) == 0);
 772                         }
 773                 } else
 774 #endif
 775                 for (hn = 0; hn < pelf->nbucket; hn++) {
 776                         for (si = pelf->elf_buckets[hn]; si; si = pelf->chains[si]) {
 777                                 ElfW(Addr) symbol_addr;
 778
 779                                 symbol_addr = (ElfW(Addr)) DL_RELOC_ADDR(pelf->loadaddr, symtab[si].st_value);
 780                                 if (symbol_addr <= (ElfW(Addr))__address && (!sf || sa < symbol_addr)) {
 781                                         sa = symbol_addr;
 782                                         sn = si;
 783                                         sf = 1;
 784                                 }
 785
 786                                 _dl_if_debug_print("Symbol \"%s\" at %p\n",
 787                                                    strtab + symtab[si].st_name, symbol_addr);
 788                         }
 789                 }
 790
 791                 if (sf) {
 792                         /* A nearest symbol has been found; fill the entries */
 793                         __info->dli_sname = strtab + symtab[sn].st_name;
 794                         __info->dli_saddr = (void *)sa;
 795                 } else {
 796                         /* No symbol found, fill entries with NULL value,
 797                         only the containing object will be returned. */
 798                         __info->dli_sname = NULL;
 799                         __info->dli_saddr = NULL;
 800                 }
 801                 return 1;
 802         }
 803 }
 804 #endif