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) 2000-2004 by Erik Andersen <andersen@codepoet.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 #define _GNU_SOURCE
  34 #include <ldso.h>
  35 #include <stdio.h>
  36
  37
  38 #if defined (__LIBDL_SHARED__)
  39
  40 /* When libdl is loaded as a shared library, we need to load in
  41  * and use a pile of symbols from ldso... */
  42
  43 extern char *_dl_find_hash(const char *, struct dyn_elf *, struct elf_resolve *, int)
  44         __attribute__ ((__weak__));
  45 extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **,
  46         struct elf_resolve *, char *, int) __attribute__ ((__weak__));
  47 extern struct elf_resolve * _dl_check_if_named_library_is_loaded(const char *, int)
  48         __attribute__ ((__weak__));
  49 extern int _dl_fixup(struct dyn_elf *rpnt, int lazy)
  50          __attribute__ ((__weak__));
  51 extern void _dl_protect_relro(struct elf_resolve * tpnt)
  52         __attribute__ ((__weak__));
  53 extern int _dl_errno __attribute__ ((__weak__));
  54 extern struct dyn_elf *_dl_symbol_tables __attribute__ ((__weak__));
  55 extern struct dyn_elf *_dl_handles __attribute__ ((__weak__));
  56 extern struct elf_resolve *_dl_loaded_modules __attribute__ ((__weak__));
  57 extern struct r_debug *_dl_debug_addr __attribute__ ((__weak__));
  58 extern unsigned long _dl_error_number __attribute__ ((__weak__));
  59 extern void *(*_dl_malloc_function)(size_t) __attribute__ ((__weak__));
  60 #ifdef __LDSO_CACHE_SUPPORT__
  61 int _dl_map_cache(void) __attribute__ ((__weak__));
  62 int _dl_unmap_cache(void) __attribute__ ((__weak__));
  63 #endif
  64 #ifdef __mips__
  65 extern void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt, int lazy)
  66         __attribute__ ((__weak__));
  67 #endif
  68 #ifdef __SUPPORT_LD_DEBUG__
  69 extern char *_dl_debug __attribute__ ((__weak__));
  70 #endif
  71
  72
  73 #else /* __LIBDL_SHARED__ */
  74
  75 /* When libdl is linked as a static library, we need to replace all
  76  * the symbols that otherwise would have been loaded in from ldso... */
  77
  78 #ifdef __SUPPORT_LD_DEBUG__
  79 char *_dl_debug  = 0;
  80 #endif
  81 char *_dl_library_path         = 0;                 /* Where we look for libraries */
  82 char *_dl_ldsopath             = 0;                 /* Location of the shared lib loader */
  83 int _dl_errno                  = 0;         /* We can't use the real errno in ldso */
  84 size_t _dl_pagesize            = PAGE_SIZE; /* Store the page size for use later */
  85 /* This global variable is also to communicate with debuggers such as gdb. */
  86 struct r_debug *_dl_debug_addr = NULL;
  87 #define _dl_malloc malloc
  88 #include "dl-progname.h"
  89 #include "../ldso/dl-hash.c"
  90 #define _dl_trace_loaded_objects    0
  91 #include "../ldso/dl-elf.c"
  92 #endif
  93
  94 static int do_dlclose(void *, int need_fini);
  95
  96
  97 static const char *dl_error_names[] = {
  98         "",
  99         "File not found",
 100         "Unable to open /dev/zero",
 101         "Not an ELF file",
 102 #if defined (__i386__)
 103         "Not i386 binary",
 104 #elif defined (__sparc__)
 105         "Not sparc binary",
 106 #elif defined (__mc68000__)
 107         "Not m68k binary",
 108 #else
 109         "Unrecognized binary type",
 110 #endif
 111         "Not an ELF shared library",
 112         "Unable to mmap file",
 113         "No dynamic section",
 114 #ifdef ELF_USES_RELOCA
 115         "Unable to process REL relocs",
 116 #else
 117         "Unable to process RELA relocs",
 118 #endif
 119         "Bad handle",
 120         "Unable to resolve symbol"
 121 };
 122
 123 void __attribute__ ((destructor)) dl_cleanup(void)
 124 {
 125         struct dyn_elf *d;
 126         for (d = _dl_handles; d; d = d->next_handle) {
 127                 do_dlclose(d, 1);
 128         }
 129 }
 130
 131 void *dlopen(const char *libname, int flag)
 132 {
 133         struct elf_resolve *tpnt, *tfrom, *tcurr;
 134         struct dyn_elf *dyn_chain, *rpnt = NULL, *dyn_ptr, *relro_ptr;
 135         struct dyn_elf *dpnt;
 136         ElfW(Addr) from;
 137         struct elf_resolve *tpnt1;
 138         void (*dl_brk) (void);
 139         int now_flag;
 140         struct init_fini_list *tmp, *runp;
 141         int nlist, i;
 142         struct elf_resolve **init_fini_list;
 143
 144         /* A bit of sanity checking... */
 145         if (!(flag & (RTLD_LAZY|RTLD_NOW))) {
 146                 _dl_error_number = LD_BAD_HANDLE;
 147                 return NULL;
 148         }
 149
 150         from = (ElfW(Addr)) __builtin_return_address(0);
 151
 152         /* Cover the trivial case first */
 153         if (!libname)
 154                 return _dl_symbol_tables;
 155
 156         _dl_map_cache();
 157
 158         /*
 159          * Try and locate the module we were called from - we
 160          * need this so that we get the correct RPATH.  Note that
 161          * this is the current behavior under Solaris, but the
 162          * ABI+ specifies that we should only use the RPATH from
 163          * the application.  Thus this may go away at some time
 164          * in the future.
 165          */
 166         tfrom = NULL;
 167         for (dpnt = _dl_symbol_tables; dpnt; dpnt = dpnt->next) {
 168                 tpnt = dpnt->dyn;
 169                 if (tpnt->loadaddr < from
 170                                 && (tfrom == NULL || tfrom->loadaddr < tpnt->loadaddr))
 171                         tfrom = tpnt;
 172         }
 173         for(rpnt = _dl_symbol_tables; rpnt->next; rpnt=rpnt->next);
 174
 175         relro_ptr = rpnt;
 176         /* Try to load the specified library */
 177 #ifdef __SUPPORT_LD_DEBUG__
 178         if(_dl_debug)
 179                 fprintf(stderr, "Trying to dlopen '%s'\n", (char*)libname);
 180 #endif
 181         tpnt = _dl_check_if_named_library_is_loaded((char *)libname, 0);
 182         if (!(tpnt))
 183                 tpnt = _dl_load_shared_library(0, &rpnt, tfrom, (char*)libname, 0);
 184         else
 185                 tpnt->usage_count++;
 186         if (tpnt == NULL) {
 187                 _dl_unmap_cache();
 188                 return NULL;
 189         }
 190
 191         dyn_chain = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
 192         _dl_memset(dyn_chain, 0, sizeof(struct dyn_elf));
 193         dyn_chain->dyn = tpnt;
 194         tpnt->rtld_flags |= (flag & RTLD_GLOBAL);
 195
 196         dyn_chain->next_handle = _dl_handles;
 197         _dl_handles = dyn_ptr = dyn_chain;
 198
 199 #ifdef __SUPPORT_LD_DEBUG__
 200         if(_dl_debug)
 201                 fprintf(stderr, "Looking for needed libraries\n");
 202 #endif
 203         nlist = 0;
 204         for (tcurr = tpnt; tcurr; tcurr = tcurr->next)
 205         {
 206                 Elf32_Dyn *dpnt;
 207                 char *lpntstr;
 208
 209                 nlist++;
 210                 tcurr->init_fini = NULL; /* clear any previous dependcies */
 211                 for (dpnt = (Elf32_Dyn *) tcurr->dynamic_addr; dpnt->d_tag; dpnt++) {
 212                         if (dpnt->d_tag == DT_NEEDED) {
 213                                 char *name;
 214
 215                                 lpntstr = (char*) (tcurr->dynamic_info[DT_STRTAB] +
 216                                                 dpnt->d_un.d_val);
 217                                 name = _dl_get_last_path_component(lpntstr);
 218                                 tpnt1 = _dl_check_if_named_library_is_loaded(name, 0);
 219 #ifdef __SUPPORT_LD_DEBUG__
 220                                 if(_dl_debug)
 221                                         fprintf(stderr, "Trying to load '%s', needed by '%s'\n",
 222                                                         lpntstr, tcurr->libname);
 223 #endif
 224                                 if (tpnt1) {
 225                                         tpnt1->usage_count++;
 226                                 } else {
 227                                         tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, 0);
 228                                         if (!tpnt1)
 229                                                 goto oops;
 230                                 }
 231                                 tpnt1->rtld_flags |= (flag & RTLD_GLOBAL);
 232                                 dyn_ptr->next = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
 233                                 _dl_memset (dyn_ptr->next, 0, sizeof (struct dyn_elf));
 234                                 dyn_ptr = dyn_ptr->next;
 235                                 dyn_ptr->dyn = tpnt1;
 236
 237                                 tmp = alloca(sizeof(struct init_fini_list)); /* Allocates on stack, no need to free this memory */
 238                                 tmp->tpnt = tpnt1;
 239                                 tmp->next = tcurr->init_fini;
 240                                 tcurr->init_fini = tmp;
 241                         }
 242                 }
 243         }
 244         init_fini_list = malloc(nlist * sizeof(struct elf_resolve *));
 245         dyn_chain->init_fini.init_fini = init_fini_list;
 246         dyn_chain->init_fini.nlist = nlist;
 247         i = 0;
 248         for (tcurr = tpnt; tcurr; tcurr = tcurr->next) {
 249                 init_fini_list[i++] = tcurr;
 250                 for(runp = tcurr->init_fini; runp; runp = runp->next){
 251                         if (!(runp->tpnt->rtld_flags & RTLD_GLOBAL)) {
 252                                 tmp = malloc(sizeof(struct init_fini_list));
 253                                 tmp->tpnt = runp->tpnt;
 254                                 tmp->next = tcurr->rtld_local;
 255                                 tcurr->rtld_local = tmp;
 256                         }
 257                 }
 258
 259         }
 260         /* Sort the INIT/FINI list in dependency order. */
 261         for (tcurr = tpnt; tcurr; tcurr = tcurr->next) {
 262                 int j, k;
 263                 for (j = 0; init_fini_list[j] != tcurr; ++j)
 264                         /* Empty */;
 265                 for (k = j + 1; k < nlist; ++k) {
 266                         struct init_fini_list *runp = init_fini_list[k]->init_fini;
 267
 268                         for (; runp; runp = runp->next) {
 269                                 if (runp->tpnt == tcurr) {
 270                                         struct elf_resolve *here = init_fini_list[k];
 271 #ifdef __SUPPORT_LD_DEBUG__
 272                                         if(_dl_debug)
 273                                                 fprintf(stderr, "Move %s from pos %d to %d in INIT/FINI list.\n", here->libname, k, j);
 274 #endif
 275                                         for (i = (k - j); i; --i)
 276                                                 init_fini_list[i+j] = init_fini_list[i+j-1];
 277                                         init_fini_list[j] = here;
 278                                         ++j;
 279                                         break;
 280                                 }
 281                         }
 282                 }
 283         }
 284 #ifdef __SUPPORT_LD_DEBUG__
 285         if(_dl_debug) {
 286                 fprintf(stderr, "\nINIT/FINI order and dependencies:\n");
 287                 for (i=0;i < nlist;i++) {
 288                         fprintf(stderr, "lib: %s has deps:\n", init_fini_list[i]->libname);
 289                         runp = init_fini_list[i]->init_fini;
 290                         for ( ;runp; runp = runp->next)
 291                                 printf(" %s ", runp->tpnt->libname);
 292                         printf("\n");
 293                 }
 294         }
 295 #endif
 296
 297         if (dyn_chain->dyn->init_flag & INIT_FUNCS_CALLED) {
 298                 /* If the init and fini stuff has already been run, that means
 299                  * the dlopen'd library has already been loaded, and nothing
 300                  * further needs to be done. */
 301                 return (void *) dyn_chain;
 302         }
 303
 304 #ifdef __SUPPORT_LD_DEBUG__
 305         if(_dl_debug)
 306                 fprintf(stderr, "Beginning dlopen relocation fixups\n");
 307 #endif
 308         /*
 309          * OK, now all of the kids are tucked into bed in their proper addresses.
 310          * Now we go through and look for REL and RELA records that indicate fixups
 311          * to the GOT tables.  We need to do this in reverse order so that COPY
 312          * directives work correctly */
 313         now_flag = (flag & RTLD_NOW) ? RTLD_NOW : 0;
 314         if (getenv("LD_BIND_NOW"))
 315                 now_flag = RTLD_NOW;
 316
 317 #ifdef __mips__
 318         /*
 319          * Relocation of the GOT entries for MIPS have to be done
 320          * after all the libraries have been loaded.
 321          */
 322         _dl_perform_mips_global_got_relocations(tpnt, !now_flag);
 323 #endif
 324
 325         if (_dl_fixup(dyn_chain, now_flag))
 326                 goto oops;
 327
 328         for (rpnt = relro_ptr->next; rpnt; rpnt = rpnt->next) {
 329                 if (rpnt->dyn->relro_size)
 330                         _dl_protect_relro(rpnt->dyn);
 331         }
 332         /* TODO:  Should we set the protections of all pages back to R/O now ? */
 333
 334
 335         /* Notify the debugger we have added some objects. */
 336         if (_dl_debug_addr) {
 337                 dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
 338                 if (dl_brk != NULL) {
 339                         _dl_debug_addr->r_state = RT_ADD;
 340                         (*dl_brk) ();
 341
 342                         _dl_debug_addr->r_state = RT_CONSISTENT;
 343                         (*dl_brk) ();
 344                 }
 345         }
 346
 347 #if defined (__LIBDL_SHARED__)
 348         /* Run the ctors and setup the dtors */
 349         for (i = nlist; i; --i) {
 350                 tpnt = init_fini_list[i-1];
 351                 if (tpnt->init_flag & INIT_FUNCS_CALLED)
 352                         continue;
 353                 tpnt->init_flag |= INIT_FUNCS_CALLED;
 354
 355                 if (tpnt->dynamic_info[DT_INIT]) {
 356                         void (*dl_elf_func) (void);
 357                         dl_elf_func = (void (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_INIT]);
 358                         if (dl_elf_func && *dl_elf_func != NULL) {
 359 #ifdef __SUPPORT_LD_DEBUG__
 360                                 if(_dl_debug)
 361                                         fprintf(stderr, "running ctors for library %s at '%x'\n", tpnt->libname, (unsigned)dl_elf_func);
 362 #endif
 363                                 (*dl_elf_func) ();
 364                         }
 365                 }
 366         }
 367 #endif
 368         _dl_unmap_cache();
 369         return (void *) dyn_chain;
 370
 371 oops:
 372         /* Something went wrong.  Clean up and return NULL. */
 373         _dl_unmap_cache();
 374         do_dlclose(dyn_chain, 0);
 375         return NULL;
 376 }
 377
 378 void *dlsym(void *vhandle, const char *name)
 379 {
 380         struct elf_resolve *tpnt, *tfrom;
 381         struct dyn_elf *handle;
 382         ElfW(Addr) from;
 383         struct dyn_elf *rpnt;
 384         void *ret;
 385
 386         handle = (struct dyn_elf *) vhandle;
 387
 388         /* First of all verify that we have a real handle
 389            of some kind.  Return NULL if not a valid handle. */
 390
 391         if (handle == NULL)
 392                 handle = _dl_symbol_tables;
 393         else if (handle != RTLD_NEXT && handle != _dl_symbol_tables) {
 394                 for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle)
 395                         if (rpnt == handle)
 396                                 break;
 397                 if (!rpnt) {
 398                         _dl_error_number = LD_BAD_HANDLE;
 399                         return NULL;
 400                 }
 401         } else if (handle == RTLD_NEXT) {
 402                 /*
 403                  * Try and locate the module we were called from - we
 404                  * need this so that we know where to start searching
 405                  * from.  We never pass RTLD_NEXT down into the actual
 406                  * dynamic loader itself, as it doesn't know
 407                  * how to properly treat it.
 408                  */
 409                 from = (ElfW(Addr)) __builtin_return_address(0);
 410
 411                 tfrom = NULL;
 412                 for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next) {
 413                         tpnt = rpnt->dyn;
 414                         if (tpnt->loadaddr < from
 415                                         && (tfrom == NULL || tfrom->loadaddr < tpnt->loadaddr)) {
 416                                 tfrom = tpnt;
 417                                 handle = rpnt->next;
 418                         }
 419                 }
 420         }
 421
 422         ret = _dl_find_hash((char*)name, handle, NULL, 0);
 423
 424         /*
 425          * Nothing found.
 426          */
 427         if (!ret)
 428                 _dl_error_number = LD_NO_SYMBOL;
 429         return ret;
 430 }
 431
 432 static int do_dlclose(void *vhandle, int need_fini)
 433 {
 434         struct dyn_elf *rpnt, *rpnt1;
 435         struct init_fini_list *runp, *tmp;
 436         ElfW(Phdr) *ppnt;
 437         struct elf_resolve *tpnt;
 438         int (*dl_elf_fini) (void);
 439         void (*dl_brk) (void);
 440         struct dyn_elf *handle;
 441         unsigned int end;
 442         int i = 0;
 443
 444         handle = (struct dyn_elf *) vhandle;
 445         rpnt1 = NULL;
 446         for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle) {
 447                 if (rpnt == handle)
 448                         break;
 449                 rpnt1 = rpnt;
 450         }
 451
 452         if (!rpnt) {
 453                 _dl_error_number = LD_BAD_HANDLE;
 454                 return 1;
 455         }
 456         if (rpnt1)
 457                 rpnt1->next_handle = rpnt->next_handle;
 458         else
 459                 _dl_handles = rpnt->next_handle;
 460         if (need_fini) {
 461                 for (i = 0; i < handle->init_fini.nlist; ++i) {
 462                         tpnt = handle->init_fini.init_fini[i];
 463                         if (tpnt->dynamic_info[DT_FINI] && tpnt->usage_count == 1 &&
 464                             !(tpnt->init_flag & FINI_FUNCS_CALLED)) {
 465                                 tpnt->init_flag |= FINI_FUNCS_CALLED;
 466                                 dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]);
 467 #ifdef __SUPPORT_LD_DEBUG__
 468                                 if(_dl_debug)
 469                                         fprintf(stderr, "running dtors for library %s at '%x'\n", tpnt->libname, (unsigned)dl_elf_fini);
 470 #endif
 471                                 (*dl_elf_fini) ();
 472                         }
 473                 }
 474         }
 475         if (handle->dyn->usage_count == 1)
 476                 free(handle->init_fini.init_fini);
 477         /* OK, this is a valid handle - now close out the file */
 478         for (rpnt = handle; rpnt; rpnt = rpnt->next) {
 479                 tpnt = rpnt->dyn;
 480                 if (--tpnt->usage_count == 0) {
 481                         end = 0;
 482                         for (i = 0, ppnt = tpnt->ppnt;
 483                                         i < tpnt->n_phent; ppnt++, i++) {
 484                                 if (ppnt->p_type != PT_LOAD)
 485                                         continue;
 486                                 if (end < ppnt->p_vaddr + ppnt->p_memsz)
 487                                         end = ppnt->p_vaddr + ppnt->p_memsz;
 488                         }
 489                         _dl_munmap((void*)tpnt->loadaddr, end);
 490                         /* Free elements in RTLD_LOCAL scope list */
 491                         for (runp = tpnt->rtld_local; runp; runp = tmp) {
 492                                 tmp = runp->next;
 493                                 free(runp);
 494                         }
 495                         /* Next, remove tpnt from the loaded_module list */
 496                         if (_dl_loaded_modules == tpnt) {
 497                                 _dl_loaded_modules = tpnt->next;
 498                                 if (_dl_loaded_modules)
 499                                         _dl_loaded_modules->prev = 0;
 500                         } else
 501                                 for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next)
 502                                         if (tpnt->next == rpnt->dyn) {
 503                                                 tpnt->next = tpnt->next->next;
 504                                                 if (tpnt->next)
 505                                                         tpnt->next->prev = tpnt;
 506                                                 break;
 507                                         }
 508
 509                         /* Next, remove tpnt from the global symbol table list */
 510                         if (_dl_symbol_tables->dyn == rpnt->dyn) {
 511                                 _dl_symbol_tables = rpnt->next;
 512                                 if (_dl_symbol_tables)
 513                                         _dl_symbol_tables->prev = 0;
 514                         } else
 515                                 for (rpnt1 = _dl_symbol_tables; rpnt1->next; rpnt1 = rpnt1->next) {
 516                                         if (rpnt1->next->dyn == rpnt->dyn) {
 517                                                 free(rpnt1->next);
 518                                                 rpnt1->next = rpnt1->next->next;
 519                                                 if (rpnt1->next)
 520                                                         rpnt1->next->prev = rpnt1;
 521                                                 break;
 522                                         }
 523                                 }
 524                         free(rpnt->dyn->libname);
 525                         free(rpnt->dyn);
 526                 }
 527                 free(rpnt);
 528         }
 529
 530
 531         if (_dl_debug_addr) {
 532                 dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
 533                 if (dl_brk != NULL) {
 534                         _dl_debug_addr->r_state = RT_DELETE;
 535                         (*dl_brk) ();
 536
 537                         _dl_debug_addr->r_state = RT_CONSISTENT;
 538                         (*dl_brk) ();
 539                 }
 540         }
 541
 542         return 0;
 543 }
 544
 545 int dlclose(void *vhandle)
 546 {
 547         return do_dlclose(vhandle, 1);
 548 }
 549
 550 char *dlerror(void)
 551 {
 552         const char *retval;
 553
 554         if (!_dl_error_number)
 555                 return NULL;
 556         retval = dl_error_names[_dl_error_number];
 557         _dl_error_number = 0;
 558         return (char *)retval;
 559 }
 560
 561 /*
 562  * Dump information to stderrr about the current loaded modules
 563  */
 564 static char *type[] = { "Lib", "Exe", "Int", "Mod" };
 565
 566 int dlinfo(void)
 567 {
 568         struct elf_resolve *tpnt;
 569         struct dyn_elf *rpnt, *hpnt;
 570
 571         fprintf(stderr, "List of loaded modules\n");
 572         /* First start with a complete list of all of the loaded files. */
 573         for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 574                 fprintf(stderr, "\t%x %x %x %s %d %s\n",
 575                                 (unsigned) tpnt->loadaddr, (unsigned) tpnt,
 576                                 (unsigned) tpnt->symbol_scope,
 577                                 type[tpnt->libtype],
 578                                 tpnt->usage_count, tpnt->libname);
 579         }
 580
 581         /* Next dump the module list for the application itself */
 582         fprintf(stderr, "\nModules for application (%x):\n",
 583                         (unsigned) _dl_symbol_tables);
 584         for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next)
 585                 fprintf(stderr, "\t%x %s\n", (unsigned) rpnt->dyn, rpnt->dyn->libname);
 586
 587         for (hpnt = _dl_handles; hpnt; hpnt = hpnt->next_handle) {
 588                 fprintf(stderr, "Modules for handle %x\n", (unsigned) hpnt);
 589                 for (rpnt = hpnt; rpnt; rpnt = rpnt->next)
 590                         fprintf(stderr, "\t%x %s\n", (unsigned) rpnt->dyn,
 591                                         rpnt->dyn->libname);
 592         }
 593         return 0;
 594 }
 595
 596 int dladdr(const void *__address, Dl_info * __info)
 597 {
 598         struct elf_resolve *pelf;
 599         struct elf_resolve *rpnt;
 600
 601         _dl_map_cache();
 602
 603         /*
 604          * Try and locate the module address is in
 605          */
 606         pelf = NULL;
 607
 608 #if 0
 609         fprintf(stderr, "dladdr( %x, %x )\n", __address, __info);
 610 #endif
 611
 612         for (rpnt = _dl_loaded_modules; rpnt; rpnt = rpnt->next) {
 613                 struct elf_resolve *tpnt;
 614
 615                 tpnt = rpnt;
 616 #if 0
 617                 fprintf(stderr, "Module \"%s\" at %x\n",
 618                                 tpnt->libname, tpnt->loadaddr);
 619 #endif
 620                 if (tpnt->loadaddr < (ElfW(Addr)) __address
 621                                 && (pelf == NULL || pelf->loadaddr < tpnt->loadaddr)) {
 622                         pelf = tpnt;
 623                 }
 624         }
 625
 626         if (!pelf) {
 627                 return 0;
 628         }
 629
 630         /*
 631          * Try and locate the symbol of address
 632          */
 633
 634         {
 635                 char *strtab;
 636                 Elf32_Sym *symtab;
 637                 int hn, si;
 638                 int sf;
 639                 int sn = 0;
 640                 ElfW(Addr) sa;
 641
 642                 sa = 0;
 643                 symtab = (Elf32_Sym *) (pelf->dynamic_info[DT_SYMTAB]);
 644                 strtab = (char *) (pelf->dynamic_info[DT_STRTAB]);
 645
 646                 sf = 0;
 647                 for (hn = 0; hn < pelf->nbucket; hn++) {
 648                         for (si = pelf->elf_buckets[hn]; si; si = pelf->chains[si]) {
 649                                 ElfW(Addr) symbol_addr;
 650
 651                                 symbol_addr = pelf->loadaddr + symtab[si].st_value;
 652                                 if (symbol_addr <= (ElfW(Addr))__address && (!sf || sa < symbol_addr)) {
 653                                         sa = symbol_addr;
 654                                         sn = si;
 655                                         sf = 1;
 656                                 }
 657 #if 0
 658                                 fprintf(stderr, "Symbol \"%s\" at %x\n",
 659                                                 strtab + symtab[si].st_name, symbol_addr);
 660 #endif
 661                         }
 662                 }
 663
 664                 if (sf) {
 665                         __info->dli_fname = pelf->libname;
 666                         __info->dli_fbase = (void *)pelf->loadaddr;
 667                         __info->dli_sname = strtab + symtab[sn].st_name;
 668                         __info->dli_saddr = (void *)sa;
 669                 }
 670                 return 1;
 671         }
 672 }