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@codpoet.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
  36
  37 #if defined (__LIBDL_SHARED__)
  38
  39 /* When libdl is loaded as a shared library, we need to load in
  40  * and use a pile of symbols from ldso... */
  41
  42 extern char *_dl_find_hash(const char *, struct dyn_elf *, int)
  43         __attribute__ ((__weak__));
  44 extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **,
  45         struct elf_resolve *, char *, int) __attribute__ ((__weak__));
  46 extern struct elf_resolve * _dl_check_if_named_library_is_loaded(const char *, int)
  47         __attribute__ ((__weak__));
  48 extern int _dl_fixup(struct dyn_elf *rpnt, int lazy)
  49          __attribute__ ((__weak__));
  50 extern int _dl_errno __attribute__ ((__weak__));
  51 extern struct dyn_elf *_dl_symbol_tables __attribute__ ((__weak__));
  52 extern struct dyn_elf *_dl_handles __attribute__ ((__weak__));
  53 extern struct elf_resolve *_dl_loaded_modules __attribute__ ((__weak__));
  54 extern struct r_debug *_dl_debug_addr __attribute__ ((__weak__));
  55 extern unsigned long _dl_error_number __attribute__ ((__weak__));
  56 extern void *(*_dl_malloc_function)(size_t) __attribute__ ((__weak__));
  57 #ifdef USE_CACHE
  58 int _dl_map_cache(void) __attribute__ ((__weak__));
  59 int _dl_unmap_cache(void) __attribute__ ((__weak__));
  60 #endif
  61 #ifdef __mips__
  62 extern void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt)
  63         __attribute__ ((__weak__));
  64 #endif
  65 #ifdef __SUPPORT_LD_DEBUG__
  66 extern char *_dl_debug __attribute__ ((__weak__));
  67 #endif
  68
  69
  70 #else /* __LIBDL_SHARED__ */
  71
  72 /* When libdl is linked as a static library, we need to replace all
  73  * the symbols that otherwise would have been loaded in from ldso... */
  74
  75 #ifdef __SUPPORT_LD_DEBUG__
  76 char *_dl_debug  = 0;
  77 #endif
  78 char *_dl_library_path         = 0;                 /* Where we look for libraries */
  79 char *_dl_ldsopath             = 0;                 /* Location of the shared lib loader */
  80 int _dl_errno                  = 0;         /* We can't use the real errno in ldso */
  81 size_t _dl_pagesize            = PAGE_SIZE; /* Store the page size for use later */
  82 /* This global variable is also to communicate with debuggers such as gdb. */
  83 struct r_debug *_dl_debug_addr = NULL;
  84 #define _dl_malloc malloc
  85 #include "dl-progname.h"
  86 #include "../ldso/dl-hash.c"
  87 #define _dl_trace_loaded_objects    0
  88 #include "../ldso/dl-elf.c"
  89 #endif
  90
  91 static int do_dlclose(void *, int need_fini);
  92
  93
  94 static const char *dl_error_names[] = {
  95         "",
  96         "File not found",
  97         "Unable to open /dev/zero",
  98         "Not an ELF file",
  99 #if defined (__i386__)
 100         "Not i386 binary",
 101 #elif defined (__sparc__)
 102         "Not sparc binary",
 103 #elif defined (__mc68000__)
 104         "Not m68k binary",
 105 #else
 106         "Unrecognized binary type",
 107 #endif
 108         "Not an ELF shared library",
 109         "Unable to mmap file",
 110         "No dynamic section",
 111 #ifdef ELF_USES_RELOCA
 112         "Unable to process REL relocs",
 113 #else
 114         "Unable to process RELA relocs",
 115 #endif
 116         "Bad handle",
 117         "Unable to resolve symbol"
 118 };
 119
 120 void __attribute__ ((destructor)) dl_cleanup(void)
 121 {
 122         struct dyn_elf *d;
 123         for (d = _dl_handles; d; d = d->next_handle) {
 124                 do_dlclose(d, 1);
 125         }
 126 }
 127
 128 void *dlopen(const char *libname, int flag)
 129 {
 130         struct elf_resolve *tpnt, *tfrom, *tcurr;
 131         struct dyn_elf *dyn_chain, *rpnt = NULL, *dyn_ptr;
 132         struct dyn_elf *dpnt;
 133         static int dl_init = 0;
 134         ElfW(Addr) from;
 135         struct elf_resolve *tpnt1;
 136         void (*dl_brk) (void);
 137         int now_flag;
 138
 139         /* A bit of sanity checking... */
 140         if (!(flag & (RTLD_LAZY|RTLD_NOW))) {
 141                 _dl_error_number = LD_BAD_HANDLE;
 142                 return NULL;
 143         }
 144
 145         from = (ElfW(Addr)) __builtin_return_address(0);
 146
 147         /* Have the dynamic linker use the regular malloc function now */
 148         if (!dl_init) {
 149                 dl_init++;
 150 #if defined (__LIBDL_SHARED__)
 151                 _dl_malloc_function = malloc;
 152 #endif
 153         }
 154
 155         /* Cover the trivial case first */
 156         if (!libname)
 157                 return _dl_symbol_tables;
 158
 159         _dl_map_cache();
 160
 161         /*
 162          * Try and locate the module we were called from - we
 163          * need this so that we get the correct RPATH.  Note that
 164          * this is the current behavior under Solaris, but the
 165          * ABI+ specifies that we should only use the RPATH from
 166          * the application.  Thus this may go away at some time
 167          * in the future.
 168          */
 169         tfrom = NULL;
 170         for (dpnt = _dl_symbol_tables; dpnt; dpnt = dpnt->next) {
 171                 tpnt = dpnt->dyn;
 172                 if (tpnt->loadaddr < from
 173                                 && (tfrom == NULL || tfrom->loadaddr < tpnt->loadaddr))
 174                         tfrom = tpnt;
 175         }
 176         for(rpnt = _dl_symbol_tables; rpnt->next; rpnt=rpnt->next);
 177         /* Try to load the specified library */
 178 #ifdef __SUPPORT_LD_DEBUG__
 179         if(_dl_debug)
 180                 fprintf(stderr, "Trying to dlopen '%s'\n", (char*)libname);
 181 #endif
 182         if (!(tpnt = _dl_check_if_named_library_is_loaded((char *)libname, 0)))
 183                 tpnt = _dl_load_shared_library(0, &rpnt, tfrom, (char*)libname, 0);
 184         if (tpnt == NULL) {
 185                 _dl_unmap_cache();
 186                 return NULL;
 187         }
 188
 189         dyn_chain = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
 190         _dl_memset(dyn_chain, 0, sizeof(struct dyn_elf));
 191         dyn_chain->dyn = tpnt;
 192         tpnt->rtld_flags |= RTLD_GLOBAL;
 193
 194         dyn_chain->next_handle = _dl_handles;
 195         _dl_handles = dyn_ptr = dyn_chain;
 196
 197 #ifdef __SUPPORT_LD_DEBUG__
 198         if(_dl_debug)
 199                 fprintf(stderr, "Looking for needed libraries\n");
 200 #endif
 201
 202         for (tcurr = tpnt; tcurr; tcurr = tcurr->next)
 203         {
 204                 Elf32_Dyn *dpnt;
 205                 char *lpntstr;
 206                 for (dpnt = (Elf32_Dyn *) tcurr->dynamic_addr; dpnt->d_tag; dpnt++) {
 207                         if (dpnt->d_tag == DT_NEEDED) {
 208
 209                                 char *name;
 210                                 lpntstr = (char*) (tcurr->loadaddr + tcurr->dynamic_info[DT_STRTAB] +
 211                                                 dpnt->d_un.d_val);
 212                                 name = _dl_get_last_path_component(lpntstr);
 213                                 tpnt1 = _dl_check_if_named_library_is_loaded(name, 0);
 214 #ifdef __SUPPORT_LD_DEBUG__
 215                                 if(_dl_debug)
 216                                         fprintf(stderr, "Trying to load '%s', needed by '%s'\n",
 217                                                         lpntstr, tcurr->libname);
 218 #endif
 219                                 dyn_ptr->next = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
 220                                 _dl_memset (dyn_ptr->next, 0, sizeof (struct dyn_elf));
 221                                 dyn_ptr = dyn_ptr->next;
 222                                 dyn_ptr->dyn = tpnt1;
 223                                 tpnt->rtld_flags |= RTLD_GLOBAL;
 224                                 if (!tpnt1) {
 225                                         tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, 0);
 226                                         if (!tpnt1)
 227                                                 goto oops;
 228                                         dyn_ptr->dyn = tpnt1;
 229                                 } else {
 230                                         tpnt1->usage_count++;
 231                                 }
 232                         }
 233                 }
 234         }
 235
 236         if (dyn_chain->dyn->init_flag & INIT_FUNCS_CALLED) {
 237                 /* If the init and fini stuff has already been run, that means
 238                  * the dlopen'd library has already been loaded, and nothing
 239                  * further needs to be done. */
 240                 return (void *) dyn_chain;
 241         }
 242 #ifdef __mips__
 243         /*
 244          * Relocation of the GOT entries for MIPS have to be done
 245          * after all the libraries have been loaded.
 246          */
 247         _dl_perform_mips_global_got_relocations(tpnt);
 248 #endif
 249
 250 #ifdef __SUPPORT_LD_DEBUG__
 251         if(_dl_debug)
 252                 fprintf(stderr, "Beginning dlopen relocation fixups\n");
 253 #endif
 254         /*
 255          * OK, now all of the kids are tucked into bed in their proper addresses.
 256          * Now we go through and look for REL and RELA records that indicate fixups
 257          * to the GOT tables.  We need to do this in reverse order so that COPY
 258          * directives work correctly */
 259         now_flag = (flag & RTLD_NOW) ? RTLD_NOW : 0;
 260         if (getenv("LD_BIND_NOW"))
 261                 now_flag = RTLD_NOW;
 262         if (_dl_fixup(dyn_chain, now_flag))
 263                 goto oops;
 264
 265         /* TODO:  Should we set the protections of all pages back to R/O now ? */
 266
 267
 268         /* Notify the debugger we have added some objects. */
 269         if (_dl_debug_addr) {
 270                 dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
 271                 if (dl_brk != NULL) {
 272                         _dl_debug_addr->r_state = RT_ADD;
 273                         (*dl_brk) ();
 274
 275                         _dl_debug_addr->r_state = RT_CONSISTENT;
 276                         (*dl_brk) ();
 277                 }
 278         }
 279
 280 #if defined (__LIBDL_SHARED__)
 281         /* Find the last library so we can run things in the right order */
 282         for (tpnt = dyn_chain->dyn; tpnt->next!=NULL; tpnt = tpnt->next)
 283                 ;
 284
 285         /* Run the ctors and set up the dtors */
 286         for (; tpnt != dyn_chain->dyn->prev; tpnt=tpnt->prev)
 287         {
 288                 /* Apparently crt1 for the application is responsible for handling this.
 289                  * We only need to run the init/fini for shared libraries
 290                  */
 291                 if (tpnt->libtype == program_interpreter)
 292                         continue;
 293                 if (tpnt->libtype == elf_executable)
 294                         continue;
 295                 if (tpnt->init_flag & INIT_FUNCS_CALLED)
 296                         continue;
 297                 tpnt->init_flag |= INIT_FUNCS_CALLED;
 298
 299                 if (tpnt->dynamic_info[DT_INIT]) {
 300                         void (*dl_elf_func) (void);
 301                         dl_elf_func = (void (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_INIT]);
 302                         if (dl_elf_func && *dl_elf_func != NULL) {
 303 #ifdef __SUPPORT_LD_DEBUG__
 304                                 if(_dl_debug)
 305                                         fprintf(stderr, "running ctors for library %s at '%x'\n", tpnt->libname, dl_elf_func);
 306 #endif
 307                                 (*dl_elf_func) ();
 308                         }
 309                 }
 310         }
 311 #endif
 312         return (void *) dyn_chain;
 313
 314 oops:
 315         /* Something went wrong.  Clean up and return NULL. */
 316         _dl_unmap_cache();
 317         do_dlclose(dyn_chain, 0);
 318         return NULL;
 319 }
 320
 321 void *dlsym(void *vhandle, const char *name)
 322 {
 323         struct elf_resolve *tpnt, *tfrom;
 324         struct dyn_elf *handle;
 325         ElfW(Addr) from;
 326         struct dyn_elf *rpnt;
 327         void *ret;
 328
 329         handle = (struct dyn_elf *) vhandle;
 330
 331         /* First of all verify that we have a real handle
 332            of some kind.  Return NULL if not a valid handle. */
 333
 334         if (handle == NULL)
 335                 handle = _dl_symbol_tables;
 336         else if (handle != RTLD_NEXT && handle != _dl_symbol_tables) {
 337                 for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle)
 338                         if (rpnt == handle)
 339                                 break;
 340                 if (!rpnt) {
 341                         _dl_error_number = LD_BAD_HANDLE;
 342                         return NULL;
 343                 }
 344         } else if (handle == RTLD_NEXT) {
 345                 /*
 346                  * Try and locate the module we were called from - we
 347                  * need this so that we know where to start searching
 348                  * from.  We never pass RTLD_NEXT down into the actual
 349                  * dynamic loader itself, as it doesn't know
 350                  * how to properly treat it.
 351                  */
 352                 from = (ElfW(Addr)) __builtin_return_address(0);
 353
 354                 tfrom = NULL;
 355                 for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next) {
 356                         tpnt = rpnt->dyn;
 357                         if (tpnt->loadaddr < from
 358                                         && (tfrom == NULL || tfrom->loadaddr < tpnt->loadaddr)) {
 359                                 tfrom = tpnt;
 360                                 handle = rpnt->next;
 361                         }
 362                 }
 363         }
 364
 365         ret = _dl_find_hash((char*)name, handle, 0);
 366
 367         /*
 368          * Nothing found.
 369          */
 370         if (!ret)
 371                 _dl_error_number = LD_NO_SYMBOL;
 372         return ret;
 373 }
 374
 375 static int do_dlclose(void *vhandle, int need_fini)
 376 {
 377         struct dyn_elf *rpnt, *rpnt1;
 378         ElfW(Phdr) *ppnt;
 379         struct elf_resolve *tpnt;
 380         int (*dl_elf_fini) (void);
 381         void (*dl_brk) (void);
 382         struct dyn_elf *handle;
 383         unsigned int end;
 384         int i = 0;
 385
 386         handle = (struct dyn_elf *) vhandle;
 387         rpnt1 = NULL;
 388         for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle) {
 389                 if (rpnt == handle)
 390                         break;
 391                 rpnt1 = rpnt;
 392         }
 393
 394         if (!rpnt) {
 395                 _dl_error_number = LD_BAD_HANDLE;
 396                 return 1;
 397         }
 398         if (rpnt1)
 399                 rpnt1->next_handle = rpnt->next_handle;
 400         else
 401                 _dl_handles = rpnt->next_handle;
 402         /* OK, this is a valid handle - now close out the file */
 403         for (rpnt = handle; rpnt; rpnt = rpnt->next) {
 404                 tpnt = rpnt->dyn;
 405                 if (--tpnt->usage_count == 0) {
 406                         if (need_fini && tpnt->dynamic_info[DT_FINI]) {
 407                                 dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]);
 408                                 (*dl_elf_fini) ();
 409                         }
 410
 411                         end = 0;
 412                         for (i = 0, ppnt = tpnt->ppnt;
 413                                         i < tpnt->n_phent; ppnt++, i++) {
 414                                 if (ppnt->p_type != PT_LOAD)
 415                                         continue;
 416                                 if (end < ppnt->p_vaddr + ppnt->p_memsz)
 417                                         end = ppnt->p_vaddr + ppnt->p_memsz;
 418                         }
 419                         _dl_munmap((void*)tpnt->loadaddr, end);
 420                         /* Next, remove tpnt from the loaded_module list */
 421                         if (_dl_loaded_modules == tpnt) {
 422                                 _dl_loaded_modules = tpnt->next;
 423                                 if (_dl_loaded_modules)
 424                                         _dl_loaded_modules->prev = 0;
 425                         } else
 426                                 for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next)
 427                                         if (tpnt->next == rpnt->dyn) {
 428                                                 tpnt->next = tpnt->next->next;
 429                                                 if (tpnt->next)
 430                                                         tpnt->next->prev = tpnt;
 431                                                 break;
 432                                         }
 433
 434                         /* Next, remove tpnt from the global symbol table list */
 435                         if (_dl_symbol_tables->dyn == rpnt->dyn) {
 436                                 _dl_symbol_tables = rpnt->next;
 437                                 if (_dl_symbol_tables)
 438                                         _dl_symbol_tables->prev = 0;
 439                         } else
 440                                 for (rpnt1 = _dl_symbol_tables; rpnt1->next; rpnt1 = rpnt1->next) {
 441                                         if (rpnt1->next->dyn == rpnt->dyn) {
 442                                                 free(rpnt1->next);
 443                                                 rpnt1->next = rpnt1->next->next;
 444                                                 if (rpnt1->next)
 445                                                         rpnt1->next->prev = rpnt1;
 446                                                 break;
 447                                         }
 448                                 }
 449                         free(rpnt->dyn->libname);
 450                         free(rpnt->dyn);
 451                 }
 452                 free(rpnt);
 453         }
 454
 455
 456         if (_dl_debug_addr) {
 457                 dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
 458                 if (dl_brk != NULL) {
 459                         _dl_debug_addr->r_state = RT_DELETE;
 460                         (*dl_brk) ();
 461
 462                         _dl_debug_addr->r_state = RT_CONSISTENT;
 463                         (*dl_brk) ();
 464                 }
 465         }
 466
 467         return 0;
 468 }
 469
 470 int dlclose(void *vhandle)
 471 {
 472         return do_dlclose(vhandle, 1);
 473 }
 474
 475 const char *dlerror(void)
 476 {
 477         const char *retval;
 478
 479         if (!_dl_error_number)
 480                 return NULL;
 481         retval = dl_error_names[_dl_error_number];
 482         _dl_error_number = 0;
 483         return retval;
 484 }
 485
 486 /*
 487  * Dump information to stderrr about the current loaded modules
 488  */
 489 static char *type[] = { "Lib", "Exe", "Int", "Mod" };
 490
 491 void dlinfo(void)
 492 {
 493         struct elf_resolve *tpnt;
 494         struct dyn_elf *rpnt, *hpnt;
 495
 496         fprintf(stderr, "List of loaded modules\n");
 497         /* First start with a complete list of all of the loaded files. */
 498         for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 499                 fprintf(stderr, "\t%x %x %x %s %d %s\n",
 500                                 (unsigned) tpnt->loadaddr, (unsigned) tpnt,
 501                                 (unsigned) tpnt->symbol_scope,
 502                                 type[tpnt->libtype],
 503                                 tpnt->usage_count, tpnt->libname);
 504         }
 505
 506         /* Next dump the module list for the application itself */
 507         fprintf(stderr, "\nModules for application (%x):\n",
 508                         (unsigned) _dl_symbol_tables);
 509         for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next)
 510                 fprintf(stderr, "\t%x %s\n", (unsigned) rpnt->dyn, rpnt->dyn->libname);
 511
 512         for (hpnt = _dl_handles; hpnt; hpnt = hpnt->next_handle) {
 513                 fprintf(stderr, "Modules for handle %x\n", (unsigned) hpnt);
 514                 for (rpnt = hpnt; rpnt; rpnt = rpnt->next)
 515                         fprintf(stderr, "\t%x %s\n", (unsigned) rpnt->dyn,
 516                                         rpnt->dyn->libname);
 517         }
 518 }
 519
 520 int dladdr(void *__address, Dl_info * __dlip)
 521 {
 522         struct elf_resolve *pelf;
 523         struct elf_resolve *rpnt;
 524
 525         _dl_map_cache();
 526
 527         /*
 528          * Try and locate the module address is in
 529          */
 530         pelf = NULL;
 531
 532 #if 0
 533         fprintf(stderr, "dladdr( %x, %x )\n", __address, __dlip);
 534 #endif
 535
 536         for (rpnt = _dl_loaded_modules; rpnt; rpnt = rpnt->next) {
 537                 struct elf_resolve *tpnt;
 538
 539                 tpnt = rpnt;
 540 #if 0
 541                 fprintf(stderr, "Module \"%s\" at %x\n",
 542                                 tpnt->libname, tpnt->loadaddr);
 543 #endif
 544                 if (tpnt->loadaddr < (ElfW(Addr)) __address
 545                                 && (pelf == NULL || pelf->loadaddr < tpnt->loadaddr)) {
 546                         pelf = tpnt;
 547                 }
 548         }
 549
 550         if (!pelf) {
 551                 return 0;
 552         }
 553
 554         /*
 555          * Try and locate the symbol of address
 556          */
 557
 558         {
 559                 char *strtab;
 560                 Elf32_Sym *symtab;
 561                 int hn, si;
 562                 int sf;
 563                 int sn = 0;
 564                 ElfW(Addr) sa;
 565
 566                 sa = 0;
 567                 symtab = (Elf32_Sym *) (pelf->dynamic_info[DT_SYMTAB] + pelf->loadaddr);
 568                 strtab = (char *) (pelf->dynamic_info[DT_STRTAB] + pelf->loadaddr);
 569
 570                 sf = 0;
 571                 for (hn = 0; hn < pelf->nbucket; hn++) {
 572                         for (si = pelf->elf_buckets[hn]; si; si = pelf->chains[si]) {
 573                                 ElfW(Addr) symbol_addr;
 574
 575                                 symbol_addr = pelf->loadaddr + symtab[si].st_value;
 576                                 if (symbol_addr <= (ElfW(Addr))__address && (!sf || sa < symbol_addr)) {
 577                                         sa = symbol_addr;
 578                                         sn = si;
 579                                         sf = 1;
 580                                 }
 581 #if 0
 582                                 fprintf(stderr, "Symbol \"%s\" at %x\n",
 583                                                 strtab + symtab[si].st_name, symbol_addr);
 584 #endif
 585                         }
 586                 }
 587
 588                 if (sf) {
 589                         __dlip->dli_fname = pelf->libname;
 590                         __dlip->dli_fbase = (void *)pelf->loadaddr;
 591                         __dlip->dli_sname = strtab + symtab[sn].st_name;
 592                         __dlip->dli_saddr = (void *)sa;
 593                 }
 594                 return 1;
 595         }
 596 }